Knoxville, TN, United States
Knoxville, TN, United States

The University of Tennessee is a public sun-grant and land-grant university headquartered in Knoxville, Tennessee, United States. Founded in 1794, two years before Tennessee entered the Union as the 16th state, it is the flagship institution of the statewide University of Tennessee system with nine undergraduate colleges and eleven graduate colleges and hosts almost 28,000 students from all 50 states and more than 100 foreign countries. In its 2014 ranking of universities, U.S. News & World Report ranked UT 106th among all national universities and 46th among public institutions of higher learning. Seven alumni have been selected as Rhodes Scholars; James M. Buchanan, M.S. '41, received the 1986 Nobel Prize in Economics. UT's ties to nearby Oak Ridge National Laboratory, established under UT President Andrew Holt and continued under the UT-Battelle partnership, allow for considerable research opportunities for faculty and students.Also affiliated with the university are the Howard H. Baker, Jr. Center for Public Policy, the University of Tennessee Anthropological Research Facility, and the University of Tennessee Arboretum, which occupies 250 acres of nearby Oak Ridge and features hundreds of species of plants indigenous to the region. The University is a direct partner of the University of Tennessee Medical Center, which is one of two Level I trauma centers in East Tennessee. As a teaching hospital, it has aggressive medical research programs.The University of Tennessee is the only university in the nation to have three presidential papers editing projects and holds collections of the papers of all three U.S. presidents from Tennessee—Andrew Jackson, James K. Polk, and Andrew Johnson. UT is one of the oldest public universities in the United States and the oldest secular institution west of the Eastern Continental Divide. Wikipedia.

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Choi S.,University of Tennessee at Knoxville
Journal of Aging and Health | Year: 2017

Objective: This study examined out-of-pocket premium burden of mid-life Asian Americans by comparing six sub-groups of Asians after controlling for geographic clustering at the county and state levels. Method: The 2007-2011 National Health Interview Survey was linked to community-level data and analyzed for 4,628 Asians (ages 50-64), including 697 Asian Indians, 1,125 Chinese, 1,393 Filipinos, 434 Japanese, 524 Koreans, and 455 Vietnamese. Non-Hispanic Whites were included as a comparison group (n = 48,135). Three-level multilevel modeling (state > county > individual) was conducted. Results: Koreans and Vietnamese were found as vulnerable sub-groups considering their lower private health insurance rates and higher uninsured rates. Among those with private insurance, Asians, specifically Filipinos, paid significantly less than non-Hispanic Whites. Moderate but significant variations in the county- and state-level variance in out-of-pocket premiums were found, especially among mid-life Asians. Discussion: This study demonstrates the importance of examining within-group heterogeneity and geographic variations in understanding premium burden among mid-life Asians. © SAGE Publications.

Li Y.,University of Tennessee at Knoxville | Gao W.,University of Tennessee at Knoxville
IEEE Transactions on Mobile Computing | Year: 2017

Mobile Cloud Computing (MCC) is of particular importance to address the conflict between the increasing complexity of user applications and the limited lifespan of mobile device's battery, by offloading the computational workloads from local devices to the remote cloud. Current offloading schemes either require the programmer's annotations, which restricts its wide application; or transmits too much unnecessary data, resulting bandwidth, and energy waste. In this paper, we propose a novel method-level offloading methodology to offload local computational workload with as least data transmission as possible. Our basic idea is to identify the contexts which are necessary to the method execution by parsing application binaries in advance and applying this parsing result to selectively migrate heap data while allowing successful method execution remotely. To further improve the efficiency of such offline parsing of application binaries, our scheme also conducts one-time parsing to all the mobile OS libraries and reuses these parsing results for different user applications. We have implemented our design over the Dalvik Virtual Machine of Android OS. Our experiments and evaluation against applications downloaded from Google Play show that our approach can save data transmission significantly comparing to existing schemes. © 2016 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.

Osborne D.R.,University of Tennessee at Knoxville
Clinical Nuclear Medicine | Year: 2017

ABSTRACT: The usage of PET/CT to monitor patients with hepatocellular carcinoma following Y radioembolization has increased; however, image quality is often poor because of low count efficiency and respiratory motion. Motion can be corrected using gating techniques but at the expense of additional image noise. Amplitude-based gating has been shown to improve quantification in FDG PET, but few have used this technique in Y liver imaging. The patients shown in this work indicate that amplitude-based gating can be used in Y PET/CT liver imaging to provide motion-corrected images with higher estimates of activity concentration that may improve posttherapy dosimetry. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.

Skutnik S.E.,University of Tennessee at Knoxville
Annals of Nuclear Energy | Year: 2017

154Eu is a nuclide of considerable importance to both non-destructive measurements of used nuclear fuel assembly burnup as well as for calculating the radiation source term for used fuel storage and transportation. However, recent evidence from code validation studies of spent fuel benchmarks have revealed evidence of a systemic bias in predicted 154Eu inventories when using ENDF/B-VII.0 and ENDF/B-VII.1 nuclear data libraries, wherein 154Eu is consistently over-predicted on the order of 10% or more. Further, this bias is found to correlate with sample burnup, resulting in a larger departure from experimental measurements for higher sample burnups. In this paper, the bias in 154Eu is characterized across eleven spent fuel destructive assay benchmarks from five different assemblies. Based on these studies, possible amendments to the ENDF/B-VII.0 and VII.1 evaluations of the 154Eun,γ155Eu are explored. By amending the location of the first resolved resonance for the 154Eu radiative capture cross-section (centered at 0.195 eV in ENDF/B-VII.0 and VII.1) to 0.188 eV and adjusting the neutron capture width proportional to 1/E, the amended cross-section evaluation was found to reduce the bias in predicted 154Eu inventories by approximately 5–7%. While the amended capture cross-section still results in a residual over-prediction of 154Eu (ranging from 2% to 9%), the effect is substantially attenuated compared with the nominal ENDF/B-VII.0 and VII.1 evaluations. © 2016 The Author

Examination of the lectotype male of Dixa modesta Johannsen revealed this species has a confused taxonomic history. It was discovered that Dixa modesta and Dixa similis Johannsen are based on the same nominal species, the former having priority. As a result, Dixa similis falls into synonymy with Dixa modesta (syn. nov.). The species long considered to correspond to the latter (since 1966 if not earlier), i.e., Dixa modesta sensu Peters, comprises three distinct sibling species based on a combination of morphological and molecular evidence. Adults of each sibling are described herein (D. elkmontensis sp. nov., D. ubiquita sp. nov., D. vockerothi sp. nov.), and the D. ubiquita species group is proposed to include them. Morphological diagnoses and a dichotomous key are provided to separate adult males of the D. ubiquita group from those of all other Nearctic species and each other, respectively. Molecular diagnoses are provided to allow identification of any life stage of these three siblings. Updated life history and distributional data are also reported for each sibling. Copyright © 2017 Magnolia Press.

Lindley L.C.,University of Tennessee at Knoxville
Journal of Palliative Medicine | Year: 2017

Background: Over 42,000 children die each year in the United States, including many with multiple complex chronic conditions (MCCCs), but little is known about whether the presence of MCCCs influences families to utilize pediatric hospice care. Objective: The study objective was to examine the relationship between MCCCs and pediatric hospice utilization among Medicaid beneficiaries. Methods: A retrospective, longitudinal cohort design was conducted with 2007-2010 California Medicaid data to examine the relationship between MCCCs (i.e., two or more MCCCs) and pediatric hospice utilization (i.e., hospice enrollment, hospice length of stay). Multivariate logistic regression with year fixed effects examined the effect of MCCCs on hospice enrollment, and negative binomial model with year fixed effects explored the relationship between MCCCs and hospice length of stay. Results: More than 10% of children enrolled in hospice care with an average length of stay of approximately three days. In the study sample, 48.6% of the children had MCCCs. MCCCs were not significantly related to hospice enrollment. However, children with MCCCs (incidence rate ratios = 4.25, p < 0.01) were associated with an increase in the number of days in hospice care. Conclusions: This study demonstrated that children with MCCCs have limited hospice care utilization at end of life. Future research is needed to explore barriers to hospice care for children with MCCCs. © Copyright 2017, Mary Ann Liebert, Inc. 2017.

Swaggerty E.A.,East Carolina University | Broemmel A.D.,University of Tennessee at Knoxville
Internet and Higher Education | Year: 2017

This study examined Master's in Reading Education students' learning experiences and preferences in an online two-course sequence designed to foster social learning and the application of knowledge through teacher action research. Interviews, discussion forum posts, and end-of-year course effectiveness surveys served as data sources. When sharing course aspects that facilitated learning, students most frequently referred to (a) synchronous and asynchronous interactions and collaboration with classmates and the instructor and (b) authentic assignments that built on one another, aiding the successful completion of action research projects that were relevant to their current interests and teaching contexts. The strength in online course effectiveness was in communication and collaboration, shared feelings of membership in the online learning community, and the authenticity of assignments and course activities. © 2016

Methods of measuring differentiation in archaeological assemblages have long been based on attribute-level analyses of assemblages. This paper considers a method of comparing assemblages as probability distributions via the Hellinger distance, as calculated through a Dirichlet-categorical model of inference using Monte Carlo methods of approximation. This method has application within practice-theory traditions of archaeology, an approach which seeks to measure and associate different factors that comprise the habitus of society. It is implemented here focusing on the question of regional food consumption habits in Republican Italy in the last two centuries BCE, toward informing a perspective on mass social change. © 2017 Elsevier Ltd

Mannik J.,University of Tennessee at Knoxville | Bailey M.W.,University of Tennessee at Knoxville | O'Neill J.C.,University of Tennessee at Knoxville
PLoS Genetics | Year: 2017

Coordination between cell division and chromosome replication is essential for a cell to produce viable progeny. In the commonly accepted view, Escherichia coli realize this coordination via the accurate positioning of its cell division apparatus relative to the nucleoids. However, E. coli lacking proper positioning of its cell division planes can still successfully propagate. Here, we characterize how these cells partition their chromosomes into daughters during such asymmetric divisions. Using quantitative time-lapse imaging, we show that DNA translocase, FtsK, can pump as much as 80% (3.7 Mb) of the chromosome between daughters at an average rate of 1700±800 bp/s. Pauses in DNA translocation are rare, and in no occasions did we observe reversals at experimental time scales of a few minutes. The majority of DNA movement occurs at the latest stages of cell division when the cell division protein ZipA has already dissociated from the septum, and the septum has closed to a narrow channel with a diameter much smaller than the resolution limit of the microscope (~250 nm). Our data suggest that the narrow constriction is necessary for effective translocation of DNA by FtsK. © 2017 Männik et al.

Lieberthal R.D.,University of Tennessee at Knoxville
Journal of Ambulatory Care Management | Year: 2017

To explore the cost for individual practices to become more patient-centered, we inventoried and calculated the cost of costly activities involved in implementing the Patient-Centered Medical Home (PCMH) as defined by the National Committee for Quality Assurance. There were 3 key findings. The cost of each PCMH-related clinical activity can be classified in 1 of 3 major categories. Cost offsets can be used to defray part of the cost recognition. The cost of PCMH transformation varied by practice with no clear level or pattern of costs. Our study suggests that small- and medium-sized practices may experience difficulty with the financial burden of PCMH recognition. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved

Fernandez P.,University of Tennessee at Knoxville
Library Hi Tech News | Year: 2017

Purpose: This column takes a big picture look at some of the technology-related trends in education to identify potential opportunities for libraries. Design/methodology/approach: In particular, it is inspired by the 2016 NMC Horizon Report, which attempts to identify and describe emerging technologies likely to have an impact on learning, teaching and creative inquiry in education. Findings: Although this report was created in the context of higher education, it impacts all libraries that support lifelong learning. In fact, some of the concepts considered in the report, such as digital literacy and makerspaces, are already well integrated into the operations of many libraries. Originality/value: This column’s focus will be on the concepts of personalized learning, competing models of education and the blending of informal and formal learning, and it will examine how libraries can use related technologies to position themselves to best assist their patrons in the future. © 2017, © Emerald Publishing Limited.

Barron M.,University of Tennessee at Knoxville
Southeastern Geographer | Year: 2017

Anniston, Alabama is home to an ongoing struggle for Environmental Justice (EJ) as residents remain embroiled in a remediation process to clean up PCB pollution left by The Monsanto Company. This paper engages with literature in Black Geographies, public memory, and environmental justice to argue that remedial processes neglect senses of place that are valued by impacted communities. In West Anniston, the predominantly black neighborhood that bore the brunt of the pollution, the remediation’s failure to restore a sense of place contributes to an ongoing erasure of black life from the landscape. As a result, the remediation transforms from a relatively benign project to one that facilitates a violence of forgetting. This paper examines how black life is remembered, commemorated, and valued by residents who participate in the remedial process. © 2017, University of North Carolina Press. All rights reserved.

Li H.,University of Tennessee at Knoxville
2016 IEEE 55th Conference on Decision and Control, CDC 2016 | Year: 2016

Communication is of key importance for networked control in cyber physical systems (CPSs). Motivated by the second law of thermodynamics, Shannon entropy is used to characterize the disorderliness of the physical dynamics in CPSs; thus communication provides negative entropy, namely information, to compensate the generation of entropy. Under mild conditions, it is shown that the entropy reduction in the physical dynamics is upper bounded by the information provided by the communication system. Hence, similarly to the Carnot heat engine efficiency, the information efficiency in CPS is defined to characterize the information utilization. Both upper and lower bounds are obtained for the information efficiency under various scenarios. The discussion on generic CPSs is then applied in concrete examples of Szilard engine and scalar linear dynamics. Numerical results for the maximal information efficiency, obtained from numerical optimizations, are provided. © 2016 IEEE.

Akerman J.,University of Tennessee at Knoxville
Journal of Architectural Education | Year: 2017

Academically driven design-build is an alternative—and even subversive—way to build, incorporating social needs, political will, and a novice yet ideological workforce. The ramifications of Modernism and the opportunities and liabilities of the postindustrial context have created ideal conditions for academically driven design-build efforts to thrive. Today’s design-build agent selectively engages high-and low-tech means in the service of a bigger agenda, understanding architecture as a social production as much as a technological one. For the case study presented here, issues of social justice and community-oriented design become key motivations for the production of architecture through a messy but rich partnership of students, faculty, community leaders, city officials, and construction professionals. © 2017, Routledge. All rights reserved.

Sharma A.,University of Tennessee at Knoxville
The Journal of bone and joint surgery. American volume | Year: 2017

BACKGROUND: Patellofemoral complications are a major cause of revision surgery following total knee arthroplasty (TKA). High forces occurring at the patellofemoral articulation coupled with a small patellofemoral contact area pose substantial design challenges. In this study, the three-dimensional (3D) in vivo mechanics of domed and anatomically shaped patellar components were compared with those of native patellae.METHODS: Ten normal knees, 10 treated with an LCS-PS (low contact stress-posterior stabilized) TKA (anatomically shaped patellar component), and 10 treated with a PFC Sigma RP-PS (press-fit condylar Sigma rotating platform-posterior stabilized) TKA (domed patellar component) were analyzed under fluoroscopic surveillance while the patient performed a weight-bearing deep knee bend from full knee extension to maximum knee flexion. Relevant bone geometries were segmented out from computed tomography (CT) scans, and computer-assisted-design (CAD) models of the implanted components were obtained from the manufacturer. Three-dimensional patellofemoral kinematics were obtained using a 3D-to-2D registration process. Contact mechanics were calculated using a distance map between the articulating patellar and femoral surfaces.RESULTS: Both patellar component designs exhibited good rotational kinematics and tracked well within the femoral trochlea when compared with the normal patella. The contact areas in the TKA groups peaked at 60° of knee flexion (mean and standard deviation, 201 ± 63.4 mm for the LCS-PS group and 218 ± 95.4 mm for the Sigma RP-PS group), and the areas were substantially smaller than those previously reported for the normal patella. Contact points in the TKA groups stayed close to the center of the patellar components.CONCLUSIONS: Both designs performed satisfactorily, although patellofemoral contact areas were reduced in comparison with those in the native patella.LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

News Article | April 23, 2017

In the 25 years since it rose on a once-neglected riverfront, the Tennessee Aquarium has become emblematic of Chattanooga’s astounding renaissance. When it was conceived in the 1980s, the Aquarium seemed like a textbook improbability for a community still haunted by its ignoble designation in 1969 as America’s most-polluted city. The grand opening of the River Journey building on May 1, 1992, was only possible thanks to a bedrock of private support and a communitywide commitment to returning to our river. The initial $45 million investment in bringing an Aquarium to Chattanooga has paid dividends on a massive scale. According to a recent economic impact study conducted by the University of Tennessee at Knoxville’s Center for Sustainable Business and Development, more than $3.293 billion has flowed into Hamilton County in the last 25 years thanks to the Aquarium. That figure represents spending by guests who reported their primary reason for coming to Chattanooga was to visit the Aquarium. “The economic power of the Aquarium is undeniable and the entire Chattanooga community has benefitted tremendously from its presence on the waterfront,” says John Phillips, one of the Aquarium’s founding board members. “For 25 years, the Aquarium has inspired a love of nature in millions of people.” In the beginning, many visitors came for the day, but as the destination has grown, the largest percentage of visitors now spend two or more nights. Research shows the average family visiting the Aquarium today spends $717 on their multi-day trip to Chattanooga compared to day-trip spending of $169. Since the Aquarium’s arrival on the waterfront, more than $5 billion in private funds have been invested in the downtown area including the addition of 11 hotels. The Aquarium’s presence supports 1,297 jobs throughout Hamilton County, and tax revenue generated by visitors to the Aquarium has tremendously boosted the local economy. According to the impact study, between 1992 and 2016, Aquarium guests paid more than $189 million in state and local taxes, which helped pay for essential civic services, from public schools and road construction to police and fire service. A private, non-profit organization since its inception, the Aquarium has achieved remarkable success without drawing on city or county tax dollars. The Aquarium consistently has received top ratings in customer satisfaction on TripAdvisor, where it is ranked as the No. 1 attraction for visitors to Chattanooga and in the Top 5 for aquariums worldwide. A broad base of contributors have helped the Aquarium to remain vibrant and innovative through the introduction new exhibits, investment in conservation programs and major additions such as the Ocean Journey building and the IMAX 3D Theater. By visiting the Tennessee Aquarium, more than 23 million people — including 2.5 million school children — have been introduced to the wonders of the aquatic world and been empowered to make informed decisions about water and wildlife. Before opening, attendance was projected to reach a first-year high of 650,000 visitors. “That we’ve managed to consistently exceeded that initial expectation by such a wide margin for so many years is remarkable,” says Keith Sanford, the Aquarium’s President and CEO. In 2016 alone, more than 745,000 guests came to Chattanooga to marvel at feisty otters, giant catfish, playful penguins, mesmerizing jellyfish and more. “That popularity reflects our long-standing commitment to offering a memorable, compelling experience that continues to improve,” Sandford says. The Aquarium continues to give back to the local community as well by providing more than $2.2 million each year in free student admissions, educational programs and transportation costs. Through its Community Outreach Program and partnership with the Chattanooga 2.0 movement, the Aquarium is taking an active role in promoting early childhood education and improving access to economically disadvantaged families in the region. “There will always be a need for the Aquarium to focus on the environmental, economic and educational well-being of our community,” said Sanford. “Gifts today, or planned future gifts, will help ensure generations to come will enjoy the Aquarium, and a vibrant Chattanooga, as much as we do today.”

News Article | April 17, 2017

The only known vehicle to have been signed twice by a U.S. president will be the highlight of a Barrett Jackson auction in West Palm Beach ​The prestigious auction company Barrett Jackson announced this week that a white 2009 King Ranch F-150 4X4 pickup autographed twice by President George W. Bush would be auctioned on Saturday April 8 at approximately 3:30pm at the South Florida Fairgrounds. The event will be broadcast nationwide on the Velocity channel. Since the announcement was made public, the auction has generated tremendous interest on social media. The truck was purchased by Allan Jones, the founder and CEO of Check Into Cash in 2013 at that year's Palm Beach Barrett Jackson auction. Prior to the auction, Bush kept the truck at his Prairie Chapel Ranch in Crawford, TX after he left the White House in 2009. It still has the original license plates. "We originally bought the President's truck to benefit the National Guard Youth Foundation and always intended to resell it for charity," said Jones. "I never imagined the F-150 would become such a collectible because the President autographed it not just once - but twice!" Jones explained that after he purchased the truck in 2013, the Bush signature was accidentally washed off during routine maintenance. When he realized what had happened, Jones asked the President if he would sign it again so that truck could be resold for charity. "President Bush graciously agreed to help us and the rest is history," Jones said. "He autographed the F-150 in the exact same location on the right airbag panel. Once word got out, everyone wanted to know when the auction was taking place." Jones, a regular on Fox News, also gained national attention for rescuing Hardwick Clothes - America's oldest tailor-made clothing manufacturer - from bankruptcy in 2014. He is well-known for donating to youth sports. The businessman donated wrestling buildings to two high schools in his hometown of Cleveland, TN, and donated the Allan Jones Aquatic Center to the University of Tennessee at Knoxville in 2008. Jones also received national attention in 2011 when he partnered with Randy Boyd (formerly Tennessee's Economic & Community Development Commissioner and a leading candidate for governor) on the Tennessee Achieves program to ensure every graduating high school senior in Bradley County, TN, could attend college free of charge. The landmark program was such a success that it was later renamed "Tennessee Promise" and adopted statewide by Gov. Bill Haslam. Most recently, Jones was given the 2017 Distinguished Service Award by the Tennessee Interscholastic Athletic Administrator's Association for his philanthropy to local schools. Jones has designated that all the proceeds from the April 8 sale of the truck will go to the Community Foundation of Cleveland and Bradley County, TN [a community based 501 (C) (3) qualified charity] for the further designated purpose of supporting one of the nation's top youth wrestling clubs (the Higher Calling Wrestling Club, Inc. in Tennessee) and the Dan Gable Museum in Waterloo, IA that benefits youth wrestling - named after the most dominant wrestler in history. "Dan Gable is a wrestling legend whose name is famous all over the world," said Jones. "He had a high school and college record of 180-1 and as an Olympic competitor in the Munich Games of 1972, he brought home the Gold Medal and was un-scored upon. As a college coach, he was a two-time NCAA champion and brought Iowa 15 NCAA titles - nine in a row from 1978 to 1986 - and 21 Big Ten team titles, not to mention Coach of the Year three times. It is our pleasure to honor this legend and help continue the fine work that he does." Gable noted even before the 2017 auction, the Bush truck had raised hundreds of thousands of dollars for veterans and Wounded Warrior programs. "Now, thanks to Janie and Allan Jones and the new purchaser, this special truck will help countless young boys and girls participating in many wrestling programs," said Gable. "It will also benefit the Dan Gable Museum's expansion of its Teaching Center, Wrestling Room, Theater and Museum." Gable added: "The monies from this auction will benefit thousands of youth wrestlers in the next few years as well as the museum. This is history." See or click for more on the West Palm Beach auction.

News Article | April 17, 2017

Only known vehicle to have been signed twice by a U.S. president will be the highlight of a Barrett Jackson auction in West Palm Beach. ​​​​​​The prestigious auction company Barrett Jackson announced this week that a white 2009 King Ranch F-150 4X4 pickup autographed twice by President George W. Bush would be auctioned on Saturday April 8 at approximately 3:30pm at the South Florida Fairgrounds. The event will be broadcast nationwide on the Velocity channel. Since the announcement was made public, the auction has generated tremendous interest on social media.  The truck was purchased by Allan Jones, the founder and CEO of Check Into Cash in 2013 at that year’s Palm Beach Barrett Jackson auction. Prior to the auction, Bush kept the truck at his Prairie Chapel Ranch in Crawford, TX after he left the White House in 2009. It still has the original license plates. “We originally bought the President’s truck to benefit the National Guard Youth Foundation and always intended to resell it for charity,” said Jones. “I never imagined the F-150 would become such a collectible because the President autographed it not just once – but twice!” Jones explained that after he purchased the truck in 2013, the Bush signature was accidentally washed off during routine maintenance. When he realized what had happened, Jones asked the President if he would sign it again so that truck could be resold for charity. “President Bush graciously agreed to help us and the rest is history,” Jones said. “He autographed the F-150 in the exact same location on the right airbag panel. Once word got out, everyone wanted to know when the auction was taking place.” Jones, a regular on Fox News, also gained national attention for rescuing Hardwick Clothes – America’s oldest tailor-made clothing manufacturer – from bankruptcy in 2014. He is well-known for donating to youth sports. The businessman donated wrestling buildings to two high schools in his hometown of Cleveland, TN, and donated the Allan Jones Aquatic Center to the University of Tennessee at Knoxville in 2008. Jones also received national attention in 2011 when he partnered with Randy Boyd (formerly Tennessee’s Economic & Community Development Commissioner and a leading candidate for governor) on the Tennessee Achieves program to ensure every graduating high school senior in Bradley County, TN, could attend college free of charge. The landmark program was such a success that it was later renamed “Tennessee Promise” and adopted statewide by Gov. Bill Haslam. Most recently, Jones was given the 2017 Distinguished Service Award by the Tennessee Interscholastic Athletic Administrator’s Association for his philanthropy to local schools. Jones has designated that all the proceeds from the April 8 sale of the truck will go to the Community Foundation of Cleveland and Bradley County, TN [a community based 501 (C) (3) qualified charity] for the further designated purpose of supporting one of the nation’s top youth wrestling clubs (the Higher Calling Wrestling Club, Inc. in Tennessee) and the Dan Gable Museum in Waterloo, IA that benefits youth wrestling - named after the most dominant wrestler in history. “Dan Gable is a wrestling legend whose name is famous all over the world,” said Jones. “He had a high school and college record of 181-1 and as an Olympic competitor in the Munich Games of 1972, he brought home the Gold Medal and was undefeated and un-scored upon.  As a college wrestler at Iowa State University, he was a two-time NCAA champion/three-time finalist and as a coach brought Iowa 15 NCAA titles – nine in a row from 1978 to 1986 - and 21 straight Big Ten team titles, not to mention Coach of the Year three times.  It is our pleasure to honor this legend and help continue the fine work that he does.” Gable noted even before the 2017 auction, the Bush truck had raised hundreds of thousands of dollars for veterans and Wounded Warrior programs. “Now, thanks to Janie and Allan Jones and the new purchaser, this special truck will help countless young boys and girls participating in many wrestling programs,” said Gable. “It will also benefit the Dan Gable Museum’s expansion of its Teaching Center, Wrestling Room, Theater and Museum.” Gable added: “The monies from this auction will benefit thousands of youth wrestlers in the next few years as well as the museum. This is history.” See or click for more on the West Palm Beach auction.

Kalupahana N.S.,University of Tennessee at Knoxville | Kalupahana N.S.,University of Peradeniya | Moustaid-Moussa N.,University of Tennessee at Knoxville
Critical Reviews in Biochemistry and Molecular Biology | Year: 2012

The renin-angiotensin system (RAS) is classically known for its role in regulation of blood pressure, fluid and electrolyte balance. In this system, angiotensinogen (Agt), the obligate precursor of all bioactive angiotensin peptides, undergoes two enzymatic cleavages by renin and angiotensin converting enzyme (ACE) to produce angiotensin I (Ang I) and angiotensin II (Ang II), respectively. The contemporary view of RAS has become more complex with the discovery of additional angiotensin degradation pathways such as ACE2. All components of the RAS are expressed in and have independent regulation of adipose tissue. This local adipose RAS exerts important auto/paracrine functions in modulating lipogenesis, lipolysis, adipogenesis as well as systemic and adipose tissue inflammation. Mice with adipose-specific Agt overproduction have a 30% increase in plasma Agt levels and develop hypertension and insulin resistance, while mice with adipose-specific Agt knockout have a 25% reduction in Agt plasma levels, demonstrating endocrine actions of adipose RAS. Emerging evidence also points towards a role of RAS in regulation of energy balance. Because adipose RAS is overactivated in many obesity conditions, it is considered a potential candidate linking obesity to hypertension, insulin resistance and other metabolic derangements. © 2012 Informa Healthcare USA, Inc.

Hagen G.,Oak Ridge National Laboratory | Papenbrock T.,Oak Ridge National Laboratory | Papenbrock T.,University of Tennessee at Knoxville | Hjorth-Jensen M.,University of Oslo
Physical Review Letters | Year: 2010

We perform coupled-cluster calculations of the energies and lifetimes of single-particle states around the doubly magic nucleus O16 based on chiral nucleon-nucleon interactions at next-to-next-to-next-to-leading order. To incorporate effects from the scattering continuum, we employ a Gamow-Hartree-Fock basis. Our calculations for the Jπ=1/2+ proton halo state in F17 and the 1/2+ state in O17 agree well with experiment, while the calculated spin-orbit splitting between 5/2+ and 3/2+ states is too small due to the lack of three-nucleon forces. Continuum effects yield a significant amount of additional binding energy for the 1/2+ and 3/2+ states in O17 and F17. © 2010 The American Physical Society.

Hagen G.,Oak Ridge National Laboratory | Hagen G.,University of Tennessee at Knoxville | Papenbrock T.,Oak Ridge National Laboratory | Papenbrock T.,University of Tennessee at Knoxville | And 3 more authors.
Reports on Progress in Physics | Year: 2014

In the past decade, coupled-cluster theory has seen a renaissance in nuclear physics, with computations of neutron-rich and medium-mass nuclei. The method is efficient for nuclei with product-state references, and it describes many aspects of weakly bound and unbound nuclei. This report reviews the technical and conceptual developments of this method in nuclear physics, and the results of coupled-cluster calculations for nucleonic matter, and for exotic isotopes of helium, oxygen, calcium, and some of their neighbors. © 2014 IOP Publishing Ltd.

Alsup J.,University of Michigan-Flint | Papantonopoulos E.,National Technical University of Athens | Siopsis G.,University of Tennessee at Knoxville
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We discuss a novel mechanism to set up a gravity dual of FFLO states in strongly coupled superconductors. The gravitational theory utilizes two U(1) gauge fields and a scalar field coupled to a charged AdS black hole. The first gauge field couples with the scalar sourcing a charge condensate below a critical temperature, and the second gauge field provides a coupling to spin in the boundary theory. The scalar is neutral under the second gauge field. By turning on an interaction between the Einstein tensor and the scalar, it is shown that, in the low temperature limit, an inhomogeneous solution possesses a higher critical temperature than the homogeneous case, giving rise to FFLO states. © 2013 Elsevier B.V.

Gerhold R.W.,University of Tennessee at Knoxville
Zoonoses and Public Health | Year: 2013

Free-roaming cat populations have been identified as a significant public health threat and are a source for several zoonotic diseases including rabies, toxoplasmosis, cutaneous larval migrans because of various nematode parasites, plague, tularemia and murine typhus. Several of these diseases are reported to cause mortality in humans and can cause other important health issues including abortion, blindness, pruritic skin rashes and other various symptoms. A recent case of rabies in a young girl from California that likely was transmitted by a free-roaming cat underscores that free-roaming cats can be a source of zoonotic diseases. Increased attention has been placed on trap-neuter-release (TNR) programmes as a viable tool to manage cat populations. However, some studies have shown that TNR leads to increased immigration of unneutered cats into neutered populations as well as increased kitten survival in neutered groups. These compensatory mechanisms in neutered groups leading to increased kitten survival and immigration would confound rabies vaccination campaigns and produce naïve populations of cats that can serve as source of zoonotic disease agents owing to lack of immunity. This manuscript is a review of the various diseases of free-roaming cats and the public health implications associated with the cat populations. © 2012 Blackwell Verlag GmbH.

Brandvain Y.,University of California at Davis | Van Cleve J.,Santa Fe Institute | Ubeda F.,University of Tennessee at Knoxville | Wilkins J.F.,Santa Fe Institute
Trends in Genetics | Year: 2011

Genomic imprinting is the differential expression of an allele based on the parent of origin. Recent transcriptome-wide evaluations of the number of imprinted genes reveal complex patterns of imprinted expression among developmental stages and cell types. Such data demand a comprehensive evolutionary framework in which to understand the effect of natural selection on imprinted gene expression. We present such a framework for how asymmetries in demographic parameters and fitness effects can lead to the evolution of genomic imprinting and place recent theoretical advances in this framework. This represents a modern interpretation of the kinship theory, is well suited to studying populations with complex social interactions, and provides predictions which can be tested with forthcoming transcriptomic data. To understand the intricate phenotypic patterns that are emerging from the recent deluge of data, future investigations of genomic imprinting will require integrating evolutionary theory, transcriptomic data, developmental and functional genetics, and natural history. © 2011 Elsevier Ltd.

Aivazian G.,University of Washington | Gong Z.,University of Hong Kong | Jones A.M.,University of Washington | Chu R.-L.,University of Texas at Dallas | And 8 more authors.
Nature Physics | Year: 2015

Local energy extrema of the bands in momentum space, or valleys, can endow electrons in solids with pseudospin in addition to real spin. In transition metal dichalcogenides this valley pseudospin, like real spin, is associated with a magnetic moment that underlies the valley-dependent circular dichroism that allows optical generation of valley polarization, intervalley quantum coherence and the valley Hall effect. However, magnetic manipulation of valley pseudospin via this magnetic moment, analogous to what is possible with real spin, has not been shown before. Here we report observation of the valley Zeeman splitting and magnetic tuning of polarization and coherence of the excitonic valley pseudospin, by performing polarization-resolved magneto-photoluminescence on monolayer WSe2. Our measurements reveal both the atomic orbital and lattice contributions to the valley orbital magnetic moment; demonstrate the deviation of the band edges in the valleys from an exact massive Dirac fermion model; and reveal a striking difference between the magnetic responses of neutral and charged valley excitons that is explained by renormalization of the excitonic spectrum due to strong exchange interactions. © 2015 Macmillan Publishers Limited.

Graf Estes K.,University of California at Davis | Hay J.F.,University of Tennessee at Knoxville
Child Development | Year: 2015

The present experiments tested bilingual infants' developmental narrowing for the interpretation of sounds that form words. These studies addressed how language specialization proceeds when the environment provides varied and divergent input. Experiment 1 (N = 32) demonstrated that bilingual 14- and 19-month-olds learned a pair of object labels consisting of the same syllable produced with distinct pitch contours (rising and falling). Infants' native languages did not use pitch contour to differentiate words. In Experiment 2 (N = 16), 22-month-old bilinguals failed to learn the labels. These results conflict with the developmental trajectory of monolinguals, who fail to learn pitch contour contrasts as labels at 17-19 months (Hay, Graf Estes, Wang, & Saffran, 2015). Bilingual infants exhibited a prolonged period of flexibility in their interpretation of potential word forms. © 2015 The Society for Research in Child Development, Inc.

Hacquard S.,Max Planck Institute for Plant Breeding Research | Schadt C.W.,Oak Ridge National Laboratory | Schadt C.W.,University of Tennessee at Knoxville
New Phytologist | Year: 2015

Interactions between trees and microorganisms are tremendously complex and the multispecies networks resulting from these associations have consequences for plant growth and productivity. However, a more holistic view is needed to better understand trees as ecosystems and superorganisms, where many interacting species contribute to the overall stability of the system. While much progress has been made on microbial communities associated with individual tree niches and the molecular interactions between model symbiotic partners, there is still a lack of knowledge of the multi-component interactions necessary for holistic ecosystem-level understanding. We review recent studies in Populus to emphasize the importance of such holistic efforts across the leaf, stem and rooting zones, and discuss prospects for future research in these important ecosystems. © 2014 New Phytologist Trust.

Bachman J.L.,Marywood University | Bachman J.L.,University of Tennessee at Knoxville | Raynor H.A.,University of Tennessee at Knoxville
Obesity | Year: 2012

Eating frequency has been inversely related to BMI but the impact of eating frequency on weight loss is unclear. This randomized controlled trial pilot study examined the effect of eating frequency on hunger, energy intake, and weight loss during a 6-month behavioral weight loss intervention. Participants (age: 51.0 ± 9.9 years, BMI: 35.5 ± 4.8 kg/m 2, 57.8% female, 94.1% white) were randomized to one of two eating frequency prescriptions: Three meal (n = 25): three eating bouts/day; or grazing (n = 26): eat at least 100 kcals every 2-3 h. Both groups attended 20 sessions and had identical dietary (1,200-1,500 kcals/day, 30% kcals from fat) and physical activity goals (200 min/week). Assessments were conducted at 0, 3, and 6 months. Using intent-to-treat analyses, grazing reported a greater eating frequency than three meal at 6 months (5.8 ± 1.1 eating bouts/day vs. 3.2 ± 0.6 eating bouts/day, P < 0.001). Grazing reported a significant reduction in hunger from 0 to 6 months (56.3 ± 15.7 mm vs. 47.9 ± 18.5 mm, P < 0.05). Energy intake and BMI were significantly (P < 0.001) reduced from 0 to 6 months (energy intake: 2,198 ± 692 kcals/day vs. 1,266 ± 353 kcals/day; BMI: 35.5 ± 4.8 kg/m 2 vs. 30.6 ± 4.9 kg/m 2). There were no significant differences in energy intake or BMI between the groups. While eating more frequently reduced hunger, it may not be related to greater reductions in energy intake or BMI during a behavioral weight loss intervention.

Kalupahana N.S.,University of Tennessee at Knoxville | Kalupahana N.S.,University of Peradeniya | Moustaid-Moussa N.,University of Tennessee at Knoxville
Obesity Reviews | Year: 2012

The renin-angiotensin system (RAS) is classically known for its role in regulation of blood pressure, fluid and electrolyte balance. Recently, several local RASs in organs such as brain, heart, pancreas and adipose tissue have also been identified. Evidence from clinical trials suggests that in addition to anti-hypertensive effects, pharmacological inhibition of RAS also provides protection against the development of type-2 diabetes. Moreover, animal models with targeted inactivation of RAS genes exhibit improved insulin sensitivity and are protected from high-fat diet-induced obesity and insulin resistance. Because there is evidence for RAS overactivation in obesity, it is possible that RAS is a link between obesity and insulin resistance. This review summarizes the evidence and mechanistic insights on the associations between RAS, obesity and insulin resistance, with special emphasis on the role of adipose tissue RAS in the pathogenesis of metabolic derangements in obesity. © 2011 The Authors. obesity reviews © 2011 International Association for the Study of Obesity.

Pruitt J.N.,University of Tennessee at Knoxville | Pruitt J.N.,University of California at Davis | Riechert S.E.,University of Tennessee at Knoxville
Proceedings of the Royal Society B: Biological Sciences | Year: 2011

How task specialization, individual task performance and within-group behavioural variation affects fitness is a longstanding and unresolved problem in our understanding of animal societies. In the temperate social spider, Anelosimus studiosus, colony members exhibit a behavioural polymorphism; females either exhibit an aggressive 'asocial' or docile 'social' phenotype. We assessed individual prey-capture success for both phenotypes, and the role of phenotypic composition on group-level prey-capture success for three prey size classes. We then estimated the effect of group phenotypic composition on fitness in a common garden, as inferred from individual egg-case masses. On average, asocial females were more successful than social females at capturing large prey, and colony-level prey-capture success was positively associated with the frequency of the asocial phenotype. Asocial colony members were also more likely to engage in prey-capture behaviour in group-foraging situations. Interestingly, our fitness estimates indicate females of both phenotypes experience increased fitness when occupying colonies containing unlike individuals. These results imply a reciprocal fitness benefit of within-colony behavioural variation, and perhaps division of labour in a spider society. © 2010 The Royal Society.

Kalupahana N.S.,University of Tennessee | Kalupahana N.S.,University of Peradeniya | Moustaid-Moussa N.,University of Tennessee | Moustaid-Moussa N.,University of Tennessee at Knoxville | Claycombe K.J.,U.S. Department of Agriculture
Molecular Aspects of Medicine | Year: 2012

Obesity is a major public health problem in the United States and worldwide. Further, obesity is causally linked to the pathogenesis of insulin resistance, metabolic syndrome and type-2 diabetes (T2D). A chronic low-grade inflammation occurring in adipose tissue is at least in part responsible for the obesity-induced insulin resistance. This adipose tissue inflammation is characterized by changes in immune cell populations giving rise to altered adipo/cytokine profiles, which in turn induces skeletal muscle and hepatic insulin resistance. Detailed molecular mechanisms of insulin resistance, adipose tissue inflammation and the implications of these findings on therapeutic strategies are discussed in this review. © 2012 Elsevier Inc. All rights reserved.

Lu X.,University of Tennessee at Knoxville | Sun K.,Tsinghua University | Guerrero J.M.,University of Aalborg | Vasquez J.C.,University of Aalborg | Huang L.,Tsinghua University
IEEE Transactions on Industrial Electronics | Year: 2014

This paper presents the coordinated control of distributed energy storage systems in dc microgrids. In order to balance the state-of-charge (SoC) of each energy storage unit (ESU), an SoC-based adaptive droop control method is proposed. In this decentralized control method, the droop coefficient is inversely proportional to the $n$th order of SoC. By using a SoC-based droop method, the ESUs with higher SoC deliver more power, whereas the ones with lower SoC deliver less power. Therefore, the energy stored in the ESU with higher SoC decreases faster than that with lower SoC. The SoC difference between each ESU gradually becomes smaller, and finally, the load power is equally shared between the distributed ESUs. Meanwhile, the load sharing speed can be adjusted by changing the exponent of SoC in the adaptive droop control. The model of the SoC-based adaptive droop control system is established, and the system stability is thereby analyzed by using this model. Simulation and experimental results from a 2 $\times$ 2.2 kW parallel converter system are presented in order to validate the proposed approach. © 1982-2012 IEEE.

Murcia C.,University of Florida | Aronson J.,CNRS Center of Evolutionary and Functional Ecology | Aronson J.,Missouri Botanical Garden | Kattan G.H.,Pontifical Xavierian University | And 4 more authors.
Trends in Ecology and Evolution | Year: 2014

The 'novel ecosystem' concept has captured the attention of scientists, managers, and science journalists, and more recently of policymakers, before it has been subjected to the scrutiny and empirical validation inherent to science. Lack of rigorous scrutiny can lead to undesirable outcomes in ecosystem management, environmental law, and policy. Contrary to the contentions of its proponents, no explicit, irreversible ecological thresholds allow distinctions between 'novel ecosystems' and 'hybrid' or 'historic' ones. Further, there is no clear message as to what practitioners should do with a 'novel ecosystem'. In addition, ecosystems of many types are being conserved, or restored to trajectories within historical ranges of variation, despite severe degradation that could have led to their being pronounced 'novel'. © 2014 Elsevier Ltd.

Paluch M.,University of Silesia | Paluch M.,University of Tennessee at Knoxville | Wojnarowska Z.,University of Silesia | Hensel-Bielowka S.,University of Silesia
Physical Review Letters | Year: 2013

In this Letter, we investigate the time evolution of the conductivity relaxation process in a prototypical ionic glass former, [Ca(NO 3)2]0.4[KNO3]0.6 (CKN), undergoing physical aging. It is demonstrated that the heterogeneous nature of molecular dynamics is manifested by an increase in the slope of the high frequency wing of the conductivity relaxation peak as the sample is annealed below the glass transition temperature. This finding is also confirmed for other ionic glass formers. Additionally, we analyze the kinetics of the change in the ionic conductivity in glassy CKN to probe its structural relaxation. © 2013 American Physical Society.

Gao W.,University of Tennessee at Knoxville | Cao G.,Pennsylvania State University | La Porta T.,Pennsylvania State University | Han J.,University of Illinois at Urbana - Champaign
IEEE Transactions on Mobile Computing | Year: 2013

Unpredictable node mobility, low node density, and lack of global information make it challenging to achieve effective data forwarding in Delay-Tolerant Networks (DTNs). Most of the current data forwarding schemes choose the nodes with the best cumulative capability of contacting others as relays to carry and forward data, but these nodes may not be the best relay choices within a short time period due to the heterogeneity of transient node contact characteristics. In this paper, we propose a novel approach to improve the performance of data forwarding with a short time constraint in DTNs by exploiting the transient social contact patterns. These patterns represent the transient characteristics of contact distribution, network connectivity and social community structure in DTNs, and we provide analytical formulations on these patterns based on experimental studies of realistic DTN traces. We then propose appropriate forwarding metrics based on these patterns to improve the effectiveness of data forwarding. When applied to various data forwarding strategies, our proposed forwarding metrics achieve much better performance compared to existing schemes with similar forwarding cost. © 2002-2012 IEEE.

Dai P.,University of Tennessee at Knoxville | Dai P.,CAS Institute of Physics | Hu J.,CAS Institute of Physics | Hu J.,Purdue University | And 2 more authors.
Nature Physics | Year: 2012

High-temperature superconductivity in the iron-based materials emerges from, or sometimes coexists with, their metallic or insulating parent compound states. This is surprising, as these undoped states exhibit dramatically different antiferromagnetic spin arrangements and Néel temperatures. Although there is a general consensus that magnetic interactions are important for superconductivity, much remains unknown concerning the microscopic origin of the magnetic states. In this review, we summarize the progress in this area, focusing on recent experimental and theoretical results, and their microscopic implications. We conclude that the parent compounds are in a state that is more complex than that implied by a simple Fermi surface nesting scenario, and a dual description including both itinerant and localized degrees of freedom is needed to properly describe these fascinating materials. © 2012 Macmillan Publishers Limited.

Zhang Y.,University of Science and Technology Beijing | Zuo T.T.,University of Science and Technology Beijing | Tang Z.,University of Tennessee at Knoxville | Gao M.C.,U.S. National Energy Technology Laboratory | And 4 more authors.
Progress in Materials Science | Year: 2014

This paper reviews the recent research and development of high-entropy alloys (HEAs). HEAs are loosely defined as solid solution alloys that contain more than five principal elements in equal or near equal atomic percent (at.%). The concept of high entropy introduces a new path of developing advanced materials with unique properties, which cannot be achieved by the conventional micro-alloying approach based on only one dominant element. Up to date, many HEAs with promising properties have been reported, e.g., high wear-resistant HEAs, Co1.5CrFeNi1.5Ti and Al0.2Co 1.5CrFeNi1.5Ti alloys; high-strength body-centered-cubic (BCC) AlCoCrFeNi HEAs at room temperature, and NbMoTaV HEA at elevated temperatures. Furthermore, the general corrosion resistance of the Cu 0.5NiAlCoCrFeSi HEA is much better than that of the conventional 304-stainless steel. This paper first reviews HEA formation in relation to thermodynamics, kinetics, and processing. Physical, magnetic, chemical, and mechanical properties are then discussed. Great details are provided on the plastic deformation, fracture, and magnetization from the perspectives of crackling noise and Barkhausen noise measurements, and the analysis of serrations on stress-strain curves at specific strain rates or testing temperatures, as well as the serrations of the magnetization hysteresis loops. The comparison between conventional and high-entropy bulk metallic glasses is analyzed from the viewpoints of eutectic composition, dense atomic packing, and entropy of mixing. Glass forming ability and plastic properties of high-entropy bulk metallic glasses are also discussed. Modeling techniques applicable to HEAs are introduced and discussed, such as ab initio molecular dynamics simulations and CALPHAD modeling. Finally, future developments and potential new research directions for HEAs are proposed.

Giraud T.,University Paris - Sud | Gladieux P.,University Paris - Sud | Gavrilets S.,University of Tennessee at Knoxville
Trends in Ecology and Evolution | Year: 2010

Emerging diseases represent a growing worldwide problem accompanying global environmental changes. There is tremendous interest in identifying the factors controlling the appearance and spread of these diseases. Here, we discuss emerging fungal plant diseases, and argue that they often result from host shift speciation (a particular case of ecological speciation). We consider the factors controlling local adaptation and ecological speciation, and show that certain life-history traits of many fungal plant pathogens are conducive for rapid ecological speciation, thus favoring the emergence of novel pathogen species adapted to new hosts. We argue that placing the problem of emerging fungal diseases of plants within the context of ecological speciation can significantly improve our understanding of the biological mechanisms governing the emergence of such diseases. © 2010 Elsevier Ltd.

Xiao D.,Oak Ridge National Laboratory | Liu G.-B.,University of Hong Kong | Feng W.,Oak Ridge National Laboratory | Feng W.,University of Tennessee at Knoxville | And 3 more authors.
Physical Review Letters | Year: 2012

We show that inversion symmetry breaking together with spin-orbit coupling leads to coupled spin and valley physics in monolayers of MoS 2 and other group-VI dichalcogenides, making possible controls of spin and valley in these 2D materials. The spin-valley coupling at the valence-band edges suppresses spin and valley relaxation, as flip of each index alone is forbidden by the valley-contrasting spin splitting. Valley Hall and spin Hall effects coexist in both electron-doped and hole-doped systems. Optical interband transitions have frequency-dependent polarization selection rules which allow selective photoexcitation of carriers with various combination of valley and spin indices. Photoinduced spin Hall and valley Hall effects can generate long lived spin and valley accumulations on sample boundaries. The physics discussed here provides a route towards the integration of valleytronics and spintronics in multivalley materials with strong spin-orbit coupling and inversion symmetry breaking. © 2012 American Physical Society.

Buchan A.,University of Tennessee at Knoxville | LeCleir G.R.,University of Tennessee at Knoxville | Gulvik C.A.,Georgia Institute of Technology | Gonzalez J.M.,University of La Laguna
Nature reviews. Microbiology | Year: 2014

Marine phytoplankton blooms are annual spring events that sustain active and diverse bloom-associated bacterial populations. Blooms vary considerably in terms of eukaryotic species composition and environmental conditions, but a limited number of heterotrophic bacterial lineages - primarily members of the Flavobacteriia, Alphaproteobacteria and Gammaproteobacteria - dominate these communities. In this Review, we discuss the central role that these bacteria have in transforming phytoplankton-derived organic matter and thus in biogeochemical nutrient cycling. On the basis of selected field and laboratory-based studies of flavobacteria and roseobacters, distinct metabolic strategies are emerging for these archetypal phytoplankton-associated taxa, which provide insights into the underlying mechanisms that dictate their behaviours during blooms.

Gritti F.,University of Tennessee at Knoxville | Horvath K.,University of Pannonia | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2012

The mass transfer kinetics of a few compounds (uracil, 112Da), insulin (5.5kDa), lysozyme (13.4kDa), and bovine serum albumin (BSA, 67kDa) in columns packed with several types of spherical particles was investigated under non-retained conditions, in order to eliminate the poorly known contribution of surface diffusion to overall sample diffusivity across the porous particles in RPLC. Diffusivity across particles is then minimum. Based on the porosity of the particles accessible to analytes, it was accurately estimated from the elution times, the internal obstruction factor (using Pismen correlation), and the hindrance diffusion factor (using Renkin correlation). The columns used were packed with fully porous particles 2.5μm Luna-C18 100Å, core-shell particles 2.6μm Kinetex-C18 100Å, 3.6μm Aeris Widepore-C18 200Å, and prototype 2.7μm core-shell particles (made of two concentric porous shells with 100 and 300Å average pore size, respectively), and with 3.3μm non-porous silica particles. The results demonstrate that the porous particle structure and the solid-liquid mass transfer resistance have practically no effect on the column efficiency for small molecules. For them, the column performance depends principally on eddy dispersion (packing homogeneity), to a lesser degree on longitudinal diffusion (effective sample diffusivity along the packed bed), and only slightly on the solid-liquid mass transfer resistance (sample diffusivity across the particle). In contrast, for proteins, this third HETP contribution, hence the porous particle structure, together with eddy dispersion govern the kinetic performance of columns. Mass transfer kinetics of proteins was observed to be fastest for columns packed with core-shell particles having either a large core-to-particle ratio or having a second, external, shell made of a thin porous layer with large mesopores (200-300Å) and a high porosity (≃0.5-0.7). The structure of this external shell seems to speed up the penetration of proteins into the particles. A stochastic model of the penetration of bulky proteins driven by a concentration gradient across an infinitely thin membrane of known porosity and pore size is suggested to explain this mechanism. Yet, under retained conditions, surface diffusion speeds up the mass transfer into the mesopores and levels the kinetic performance of particles built with either one or two porous shells. © 2012 Elsevier B.V.

Klemes J.J.,University of Pannonia | Varbanov P.S.,University of Pannonia | Huisingh D.,University of Tennessee at Knoxville
Journal of Cleaner Production | Year: 2012

There is a growing understanding that environmental challenges, which mankind is facing cannot be solved by technological or societal sciences alone. An integrated, multi-disciplinary approach is needed, which combines the strengths of new advances in Cleaner Production technologies and political implementation of the policies and programs that are designed to help to ensure sustainable societal development based upon healthy eco-systems. With this aim in mind the organisers of the 14th International Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction - PRES'11 - and the Editor & Publishers of the Journal of Cleaner Production joined efforts in developing this Special Issue. The main topics include environmental impact assessments, footprint assessment tools, new developments in biofuels and hydrogen production and sustainable consumption. A major section is also devoted to the increasingly important area of CO 2 minimisation. The final part addresses recent advances in electrical vehicles. Key conclusions and future trends include: Cleaner production is a more and more important part of the planning, design, operation and management in all industrial sectors. To assess and evaluate progress towards more sustainable systems, it is essential that proper monitoring of the environmental and social impacts is done on a regular basis and that the results are used to help focusing societal attention on ways to make further improvements towards sustainable societal lifestyles. Key CO 2-related aspects are avoidance, reuse, mitigation and minimisation. The preferred option of cleaner production is prevention or minimisation by better product design, process optimisation, monitoring, training and management combined with improved governmental policies that are uniformly enforced for all industrial and business facilities. An inter-linked research field, which is receiving increasing attention is energy storage related to electrical cars. They have the potential to merge several interesting options related to smart grids by using networks of car batteries for low, extra investment, electricity storage. It is anticipated that they, as well as various other opportunities, for cleaner transport will receive more attention in the coming decade. Copyright © 2012 Published by Elsevier Ltd. All rights reserved.

Moon H.S.,University of Tennessee at Knoxville | Li Y.,University of Connecticut | Stewart Jr. C.N.,University of Tennessee at Knoxville
Trends in Biotechnology | Year: 2010

Gene flow from transgenic plants is an environmental and regulatory concern. While biocontainment might be achieved using male sterility or transgenic mitigation tools, we believe that perhaps the optimal solution might be simply to remove transgenes from pollen. Male sterility might not be ideal for many pollinators, and might not be implementable using standardized genes. Transgenic mitigation might not be useful to control conspecific gene flow (e.g. crop to crop), and relies on competition and not biocontainment per se. Site-specific recombination systems could allow highly efficient excision of transgenes in pollen to eliminate, or at least minimize, unwanted transgene movement via pollen dispersal. There are other potential biotechnologies, such as zinc finger nucleases, that could be also used for transgene excision. © 2009 Elsevier Ltd. All rights reserved.

Wang Y.,RF Micro Devices | Liu Q.,Beijing Institute of Technology | Fathy A.E.,University of Tennessee at Knoxville
IEEE Transactions on Geoscience and Remote Sensing | Year: 2013

In this paper, we discuss using field-programmable gate arrays (FPGAs) to process either time- or frequency-domain signals in human sensing radar applications. One example will be given for a continuous-wave (CW) Doppler radar and another for an ultrawideband (UWB) pulse-Doppler (PD) radar. The example for the CW Doppler radar utilizes a novel superheterodyne receiver to suppress low-frequency noise and includes a digital downconverter module implemented in an FPGA. Meanwhile, the UWB PD radar employs a carrier-based transceiver and a novel equivalent time sampling scheme based on FPGA for narrow pulse digitization. Highly integrated compact data acquisition hardware has been implemented and exploited in both radar prototypes. Typically, the CW Doppler radar is a low-cost option for single human activity monitoring, vital sign detection, etc., where target range information is not required. Meanwhile, the UWB PD radar is more advanced in through-wall sensing, multiple-object detection, real-time target tracking, and so on, where a high-resolution range profile is acquired together with a micro-Doppler signature. Design challenges, performance comparison, pros, and cons will be discussed in detail. © 2012 IEEE.

Lewis J.A.,University of Tennessee at Knoxville | Neville H.A.,University of Illinois at Urbana - Champaign
Journal of Counseling Psychology | Year: 2015

The purpose of this study was to develop a measure of gendered racial microaggressions (i.e., subtle and everyday verbal, behavioral, and environmental expressions of oppression based on the intersection of one's race and gender) experienced by Black women by applying an intersectionality framework to Essed's (1991) theory of gendered racism and Sue, Capodilupo, et al.'s (2007) model of racial microaggressions. The Gendered Racial Microaggressions Scale (GRMS), was developed to assess both frequency and stress appraisal of microaggressions, in 2 separate studies. After the initial pool of GRMS items was developed, we received input from a community-based focus group of Black women and an expert panel. In Study 1, an exploratory factor analysis using a sample of 259 Black women resulted in a multidimensional scale with 4 factors as follows: (a) Assumptions of Beauty and Sexual Objectification, (b) Silenced and Marginalized, (c) Strong Black Woman Stereotype, and (d) Angry Black Woman Stereotype. In Study 2, results of confirmatory factor analyses using an independent sample of 210 Black women suggested that the 4-factor model was a good fit of the data for both the frequency and stress appraisal scales. Supporting construct validity, the GRMS was positively related to the Racial and Ethnic Microaggressions Scale (Nadal, 2011) and the Schedule of Sexist Events (Klonoff & Landrine, 1995). In addition, the GRMS was significantly related to psychological distress, such that greater perceived gendered racial microaggressions were related to greater levels of reported psychological distress. Implications for future research and practice are discussed. © 2015 American Psychological Association.

University of Tennessee at Knoxville and University of Connecticut | Date: 2013-09-10

An implantable bio-sensing platform architecture that enables the wireless selection, calibration and reading of multiple sensors, as well as checking the power levels of the solar powering source energizing various electronic and optoelectronic devices and circuits embedded in the platform. It also permits checking the operation of the potentiostats interfacing with each amperometric analyte sensor. The platform is flexible to include FET based sensors for protein sensing as well as other applications including pH sensing. In addition, other physiological sensors can be integrated in the platform.

The 27-year-old traditional breeding program, which has attempted to infuse blight resistance from the Chinese chestnut tree into American chestnuts, is receiving a boost from tree molecular geneticists at Penn State and five other universities working collaboratively in a bid to improve the process. While traditional breeding has been taking place, so have parallel lines of research into genetic modification and also bio-control of the fungus that causes the blight. "Teams of researchers are now at a crossroads where all three methodologies may be combined to provide a more robust product," said Sara Fitzsimmons, a research technologist who is also director of restoration for The American Chestnut Foundation, the group leading the chestnut-restoration effort. "By merging successes in genetic modification, hypovirulence and traditional breeding, restoration of a disease-resistant American chestnut tree is closer." The chestnut blight—which wiped out the American chestnut species across its 180-million-acre range in the first half of the 20th century—is caused by a fungus inadvertently introduced from Asia. Some view the loss of the chestnuts, which produced untold tons of food for wildlife and food and lumber for humans, as one of the worst U.S. ecological disasters. "We didn't account in our time estimates for how long it would take after we got nuts with blight resistance to plant out orchards and select progeny with the strongest resistance and eliminate material susceptible to the blight," said Fitzsimmons. "When we plant these trees with nuts generated by our latest generation of backcrossed trees, only 1 percent have the resistance that we are looking for. So you can imagine, if we're planting 27,000 trees, only about 270 have the combination of blight resistance and American chestnut characteristics we need." The chestnut orchard in The Arboretum at Penn State and the Chestnut Foundation's Meadowview Research Farms in Virginia contains the latest generation of traditionally bred plant material with the most chestnut blight resistance and American character. At the Penn State orchard last spring, Fitzsimmons and her colleagues conducted controlled pollination of selected trees. The tactic underlines challenges faced by researchers trying to bring back the American chestnut. "Because we still haven't finished planting out the orchard and we still haven't finished selecting and culling highly blight-susceptible trees we planted a few years ago, the blight-susceptible trees are pollinating trees that are selected and resistant," she explained. "So, when we collect nuts in this orchard, they have a wide variety of resistance and very few have full resistance, because there is so much pollen at this location." Fitzsimmons and other researchers bagged flowers on selected trees to keep unwanted pollen away and introduced pollen from trees known to have a high level of blight resistance. Blight resistance is measured after the fungus that causes the disease is applied to wounds made in the young chestnuts' trunks or branches. "When we were collecting open-pollination nuts, we were hoping that they wouldn't have this much susceptibility in the progeny, but because there is so much susceptibility in the pollen cloud, we were not able to get rid of it," Fitzsimmons explained. "So this year, we took the best of the best, and we performed controlled pollination. Controlled pollination, however, yields about 50 percent or fewer nuts than open pollination does. "These control-pollinated nuts will be a true test of levels of resistance possible in this population." The American Chestnut Foundation started its cross-breeding program in 1989, and Penn State got involved in 1997. The first orchard was planted by Professor Emeritus of Forest Genetics Henry Gerhold on State Game Land 176, not far from the University Park campus, as part of Christmas tree improvement research he was conducting. Kim Steiner, professor of forest biology and now arboretum director—and also the senior science adviser to The American Chestnut Foundation—then conducted silvicultural trials with chestnuts at the University's Stone Valley Recreation Area, starting in 1997. The chestnut orchard in The Arboretum at Penn State was started in 2002. In 2004, Professor of Molecular Genetics John Carlson started to examine the underlying molecular components of blight resistance. In a project funded by the National Science Foundation from 2006 to 2009, his laboratory identified several potential blight-resistance genes by painstakingly comparing genes expressed in cankers of susceptible American and resistant Chinese chestnut plants. With funding from The Forest Health Initiative, Carlson since 2009 has led a project to sequence and characterize the entire genome of one of the blight-resistant donor Chinese chestnut trees in the chestnut foundation's breeding program, with an eye toward identifying all of the resistance genes. Carlson, director of Penn State's Schatz Center for Tree Molecular Genetics, is now collaborating with tree geneticists and researchers at the University of Kentucky, Clemson University, Virginia Tech, the University of Tennessee at Knoxville, the State University of New York at Syracuse and the foundation to unravel the mystery of blight resistance. The group also is testing a genome-sequence-based system to accelerate the selection of blight-resistant plants that now are genetically American, using nuts harvested this fall from the trees that underwent controlled pollination in the Penn State orchard. Developing blight resistance in American chestnut is complex and challenging, concedes Carlson, who also has applied molecular-genetics techniques to modify poplar trees for bioprocessing and biofuels. "Our aspirations are to move the resistance genes from Chinese chestnuts into American chestnuts and find out which combinations of genes would give the best resistance," he said. "That has proven to be extremely complicated because more than a few genes are involved, and we haven't yet pinned down which ones are the most important. Genetic engineering groups have been testing about a dozen blight-resistance genes that have been identified. We have to test them in combination because we know that blight resistance is not a single-gene trait, so we have to test multiple combinations of genes, which is very difficult to do and takes time." If biotechnology researchers do develop a genetically modified, blight-free American chestnut, current federal regulations would limit distribution of the plants, Fitzsimmons noted. An estimated five years will be required to have the product deregulated by governmental agencies before it is available for widespread distribution and planting. "We expect to have research plantings of GMO backcross trees within the next two years," she said. "While GMO cannot be allowed to open pollinate under current regulations, GMO American chestnuts appear to offer an excellent chance of creating a blight-resistant American chestnut." The Chestnut Foundation also is planning to soon deploy a biocontrol, developed by pathologists from West Virginia University and the University of Maryland, to weaken the fungus that causes chestnut blight. The biocontrol involves infecting the fungus that causes chestnut blight with a virus that makes the fungus sick and reduces its virulence. "We are now focusing on the three Bs in concert to restore the American chestnut—breeding, biocontrols and biotechnology," Fitzsimmons said. "This gives us a bigger suite of tools to fight off this fungus and blight." But even if all of these initiatives to restore the American chestnut come off without a hitch, it may take a century or more to see chestnuts again across their former range, from Maine to Florida, she concedes. Based on research she is conducting in Maine and Vermont on naturally regenerating sites, it looks like it takes at least 20 years for a plot of chestnuts just to become established beneath a forest canopy. "Tree breeding, especially hardwoods, takes extraordinary patience because results often aren't seen over a lifetime—we knew that," she said. "To see a naturally regenerating American chestnut population regaining its reproductive niche in the ecological landscape will take a long time—50 years at least after we plant nuts from truly blight-resistant trees." No matter how long it takes, the chestnut reintroduction effort is monumental, Steiner stressed, because it is likely the most complex and long-term attempt to rescue a plant species ever pursued. Breeding trees to develop blight resistance is difficult enough, but in this particular case the rescue requires transferring genes from one species to another while still maintaining the genetic diversity of the original species. "A 'horticultural' solution—where a successful product is commonly a single, clonally propagated genotype—is not sufficient because we are attempting to restore a species to the wild where it must survive, reproduce and eventually evolve on its own," Steiner said. "A remarkable feature of this project is that it is being performed by a small non-profit with the help of thousands of volunteers. Fortunately, the work of the foundation has catalyzed millions of dollars in research by collaborators such as John Carlson, and this has greatly assisted progress." Explore further: Using DNA 'fingerprinting' to understand ancestry and immunity of trees

Veiga-Parga T.,University of Tennessee at Knoxville | Suryawanshi A.,Emory Vaccine Center and Yerkes Primate Research Center | Rouse B.T.,University of Tennessee at Knoxville
PLoS Pathogens | Year: 2011

Ocular herpes simplex virus infection can cause a blinding CD4 + T cell orchestrated immuno-inflammatory lesion in the cornea called Stromal Keratitis (SK). A key to controlling the severity of SK lesions is to suppress the activity of T cells that orchestrate lesions and enhance the representation of regulatory cells that inhibit effector cell function. In this report we show that a single administration of TCDD (2, 3, 7, 8- Tetrachlorodibenzo-p-dioxin), a non-physiological ligand for the AhR receptor, was an effective means of reducing the severity of SK lesions. It acted by causing apoptosis of Foxp3 - CD4 + T cells but had no effect on Foxp3 + CD4 + Tregs. TCDD also decreased the proliferation of Foxp3 - CD4 + T cells. The consequence was an increase in the ratio of Tregs to T effectors which likely accounted for the reduced inflammatory responses. In addition, in vitro studies revealed that TCDD addition to anti-CD3/CD28 stimulated naïve CD4 + T cells caused a significant induction of Tregs, but inhibited the differentiation of Th1 and Th17 cells. Since a single TCDD administration given after the disease process had been initiated generated long lasting anti-inflammatory effects, the approach holds promise as a therapeutic means of controlling virus induced inflammatory lesions. © 2011 Veiga-Parga, et al.

Jiang W.,University of Pennsylvania | Jiang W.,University of Tennessee at Knoxville | Boder E.T.,University of Tennessee at Knoxville
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010

Class II major histocompatibility complex (MHC-II) proteins govern stimulation of adaptive immunity by presenting antigenic peptides to CD4+ T lymphocytes. Many allelic variants of MHC-II exist with implications in peptide presentation and immunity; thus, high-throughput experimental tools for rapid and quantitative analysis of peptide binding to MHC-II are needed. Here, we present an expression system wherein peptide and MHC-II are codisplayed on the surface of yeast in an intracellular association-dependent manner and assayed by flow cytometry. Accordingly, the relative binding of different peptides and/or MHC-II variants can be assayed by genetically manipulating either partner, enabling the application of directed evolution approaches for high-throughput characterization or engineering. We demonstrate the application of this tool to map the side-chain preference for peptides binding to HLA-DR1 and to evolve novel HLA-DR1 mutants with altered peptide-binding specificity.

Gardner R.M.,Dominion | Liu Y.,University of Tennessee at Knoxville
IEEE Transactions on Smart Grid | Year: 2012

Using data from high-resolution wide-area GPS-synchronized measurements to detect and analyze disturbances within a synchronous electrical interconnection is not trivial. Deterministic methods often fall prey to the non-stationary noisy nature of this type of data. This paper dwells on the location of noteworthy events within blue-sky ambient data taken from particularly noisy environments. The statistical processing used to detect and analyze power system events is congealed into a concise and tunable algorithm that is applicable to a multitude of data types. The data analyzed herein is drawn from FNET, a wide-area measurement system deployed worldwide at standard end-user distribution voltages. © 2011 IEEE.

Ishikawa R.,Oak Ridge National Laboratory | Lupini A.R.,Oak Ridge National Laboratory | Findlay S.D.,Monash University | Taniguchi T.,Japan National Institute of Materials Science | Pennycook S.J.,University of Tennessee at Knoxville
Nano Letters | Year: 2014

Materials properties, such as optical and electronic response, can be greatly enhanced by isolated single dopants. Determining the full three-dimensional single-dopant defect structure and spatial distribution is therefore critical to understanding and adequately tuning functional properties. Combining quantitative Z-contrast scanning transmission electron microscopy images with image simulations, we show the direct determination of the atomic-scale depth location of an optically active, single atom Ce dopant embedded within wurtzite-type AlN. The method represents a powerful new tool for reconstructing three-dimensional information from a single, two-dimensional image. © 2014 American Chemical Society.

Jiang D.,UTRC - United Technologies Research Center | Wang F.,University of Tennessee at Knoxville
IEEE Transactions on Power Electronics | Year: 2014

Current ripple is generated by pulse width modulation (PWM) switching in multiphase voltage source converters (VSCs). This letter introduces a general and fast current ripple prediction method for multiphase VSCs with arbitrary phase numbers. An equivalent converter-load model is derived for the n-phase converter system. By combining the common-mode voltage of both converter terminal and load, the equivalent circuit for each phase can be modeled. The voltage dropping on the ac inductor can be calculated for the 2n + 2 zones in each switching cycle based on the equivalent circuit for each phase. Then the current ripple can be reconstructed based on the linear di/dt model in each zone. Simulation examples of five-and six-phase converters prove that the current prediction method is accurate. With this real-time prediction method, the current ripple can be controlled in application. An application example of five-phase variable switching frequency PWM is introduced to control the peak current ripple and reduce the switching losses. © 2013 IEEE.

Xu Z.,University of Tennessee at Knoxville | Li M.,Magna E Car Systems | Wang F.,University of Tennessee at Knoxville | Liang Z.,Oak Ridge National Laboratory
IEEE Transactions on Power Electronics | Year: 2013

In order to satisfy the high-density requirement and harsh thermal conditions while reducing cost in future electric and hybrid electric vehicles (HEV), a systematic study of a 1200-V trench-gate field-stop Si insulated gate bipolar transistor (IGBT) operating up to 200°C is performed to determine its feasibility, issues, and application guideline. The device forward conduction characteristics, leakage current, and switching performance are evaluated at various temperatures. Based on the device characterization, the impact of the increased junction temperature on a traction drive converter loss and thermal management is analyzed. It is shown that by extending the device junction temperature to 200°C, the additional 65°C coolant loop can be eliminated without compromising power density and thermal management design. Furthermore, the possible failure mechanisms including latching, short circuit fault, and avalanche capability are tested at elevated temperatures. The criteria considering thermal stability, thermal management, short circuit capability, and avalanche capability are given at 200°Cto ensure the safe and reliable operation of Si IGBTs. © 1986-2012 IEEE.

Jiang D.,UTRC - United Technologies Research Center | Wang F.F.,University of Tennessee at Knoxville
IEEE Transactions on Power Electronics | Year: 2013

Compared with the widely used constant switching frequency pulse-width-modulation (PWM) method, variable switching frequency PWM can benefit more because of the extra freedom. Based on the analytical expression of current ripple of three-phase converters, variable switching frequency control methods are proposed to satisfy different ripple requirements. Switching cycle Ts is updated in DSP in every interruption period based on the ripple requirement. Two methods are discussed in this paper. The first method is designed to arrange the current ripple peak value within a certain value and can reduce the equivalent switching frequency and electromagnetic interference (EMI) noise; the second method is designed to keep ripple current RMS value constant and reduce the EMI noise. Simulation and experimental results show that variable switching frequency control could improve the performance of EMI and efficiency without impairing the power quality. © 1986-2012 IEEE.

Shu T.,Oakland University | Li H.,University of Tennessee at Knoxville
IEEE Journal on Selected Areas in Communications | Year: 2014

In this paper, we study the quality-of-service (QoS) support for realtime traffic in cognitive radio (CR) networks when spectrum availability and quality is not known a priori. A resource-constrained CR relies on sequential channel sensing and probing to resolve spectrum uncertainty and search for good transmission opportunities in real time. We are interested in maximizing the effective throughput the CR can achieve with a desired confidence (success probability) under a spectrum access delay constraint. This quantity can be interpreted as the QoS-compliant (e.g., min-rate and delay) capacity of the CR link under the uncertain spectrum environment. The optimization is formulated as a finite-horizon optimal stopping problem under the objective of maximizing a given percentile of the rate of return at the stopping time. This formulation cannot be directly solved by classical optimal stopping theory, because the latter only supports a mean-reward objective function. A novel transformation is developed to convert the problem into solving a series of sub problems, each of which optimizes a transformed mean-reward of the original problem and therefore can be solved using classical optimal stopping method. We prove the monotonicity of the sub problems, based on which we develop a fast algorithm to efficiently find the unique solution to the original problem. To account for different MAC mechanisms used in practice, our analysis considers both non-recall and recall channel decision strategies. Extensive simulations are performed to verify the effectiveness and significance of the optimization. We show that significant gains (e.g., over 30%) on the QoS-compliant capacity can be achieved by the proposed algorithm when compared with the counterparts. © 1983-2012 IEEE.

Sundqvist M.K.,Swedish University of Agricultural Sciences | Sanders N.J.,University of Tennessee at Knoxville | Sanders N.J.,Rocky Mountain Biological Laboratory | Sanders N.J.,Copenhagen University | Wardle D.A.,Swedish University of Agricultural Sciences
Annual Review of Ecology, Evolution, and Systematics | Year: 2013

Community structure and ecosystem processes often vary along elevational gradients. Their responses to elevation are commonly driven by changes in temperature, and many community- and ecosystem-level variables therefore frequently respond similarly to elevation across contrasting gradients. There are also many exceptions, sometimes because other factors such as precipitation can also vary with elevation. Given this complexity, our capacity to predict when and why the same variable responds differently among disparate elevational gradients is often limited. Furthermore, there is utility in using elevational gradients for understanding community and ecosystem responses to global climate change at much larger spatial and temporal scales than is possible through conventional ecological experiments. However, future studies that integrate elevational gradient approaches with experimental manipulations will provide powerful information that can improve predictions of climate change impacts within and across ecosystems. © Copyright ©2013 by Annual Reviews. All rights reserved.

Mei J.,Nanjing Southeast University | Xiao B.,University of Tennessee at Knoxville | Shen K.,Harbin Institute of Technology | Tolbert L.M.,University of Tennessee at Knoxville | Zheng J.Y.,Nanjing Southeast University
IEEE Transactions on Power Electronics | Year: 2013

This paper proposed an improved phase disposition pulse width modulation (PDPWM) for a modular multilevel inverter which is used for Photovoltaic grid connection. This new modulation method is based on selective virtual loop mapping, to achieve dynamic capacitor voltage balance without the help of an extra compensation signal. The concept of virtual submodule (VSM) is first established, and by changing the loop mapping relationships between the VSMs and the real submodules, the voltages of the upper/lower arm's capacitors can be well balanced. This method does not requiring sorting voltages from highest to lowest, and just identifies the MIN and MAX capacitor voltage's index which makes it suitable for a modular multilevel converter with a large number of submodules in one arm. Compared to carrier phase-shifted PWM (CPSPWM), this method is more easily to be realized in field-programmable gate array and has much stronger dynamic regulation ability, and is conducive to the control of circulating current. Its feasibility and validity have been verified by simulations and experiments. © 1986-2012 IEEE.

Dong S.,Nanjing Southeast University | Liu J.-M.,Nanjing University | Dagotto E.,University of Tennessee at Knoxville | Dagotto E.,Oak Ridge National Laboratory
Physical Review Letters | Year: 2014

The iron selenides are important because of their superconducting properties. Here, an unexpected phenomenon is predicted to occur in an iron-selenide compound with a quasi-one-dimensional ladder geometry: BaFe2Se3 should be a magnetic ferrielectric system, driven by its magnetic block order via exchange striction. A robust performance (high TC and large polarization) is expected. Different from most multiferroics, BaFe2Se3 is ferrielectric, with a polarization that mostly cancels between ladders. However, its strong magnetostriction still produces a net polarization that is large (∼0.1μC/cm2) as compared with most magnetic multiferroics. Its fully ferroelectric state, with energy only slightly higher than the ferrielectric, has a giant improper polarization ∼2-3μC/cm2. © 2014 American Physical Society.

Voy B.H.,University of Tennessee at Knoxville
Journal of Nutrition | Year: 2011

Genetic variation in a population creates an impressive spectrum of phenotypic diversity, particularly when changes in diet or the environment are imposed on the population. Genome-wide association studies have become a powerful tool for linking sequence variants with overlying systems level phenotypes, but they do not provide insight into the mechanisms through which genetic variation drives phenotypic variation. Systems genetics is an emerging discipline that provides a means to fill this knowledge gap by assembling the hierarchy of interactions among genes, proteins, and other intermediate phenotypes that manifest as phenotypic variation. When applied to nutrition, systems genetics enables the identification of pathways through which nutrients influence health and the determination of the mechanisms that cause individuals to differ in their response to diet. © 2011 American Society for Nutrition.

Hedberg T.,University of Tennessee at Knoxville
Environmental Values | Year: 2016

In Animal Ethics in Context, Clare Palmer tries to harmonise two competing approaches to animal ethics. One focuses on the morally relevant capacities that animals possess. The other is the Laissez-Faire Intuition (LFI): the claim that we have duties to assist domesticated animals but should (at least generally) leave wild animals alone. In this paper, I critique the arguments that Palmer offers in favour of the No-Contact LFI–the view that we have (prima facie) duties not to harm wild animals but no duties to assist them. I argue that Palmer’s endorsement of the No-Contact LFI is unwarranted. Her arguments actually provide strong reasons to endorse what I call the Gradient View–a position that posits weak presumptive duties to assist wild animals that become stronger as our relations with the animals grow stronger. © 2016 The White Horse Press.

Gavrilets S.,University of Tennessee at Knoxville
Proceedings of the National Academy of Sciences of the United States of America | Year: 2012

A crucial step in recent theories of human origins is the emergence of strong pair-bonding between males and females accompanied by a dramatic reduction in the male-to-male conflict over mating and an increased investment in offspring. How such a transition from promiscuity to pair-bonding could be achieved is puzzling. Many species would, indeed, be much better off evolutionarily if the effort spent on male competition over mating was redirected to increasing female fertility or survivorship of offspring. Males, however, are locked in a "social dilemma," where shifting one's effort from "appropriation" to "production" would give an advantage to free-riding competitors and therefore, should not happen. Here, I first consider simple models for four prominent scenarios of the human transition to pair-bonding: communal care, mate guarding, food for mating, and mate provisioning. I show that the transition is not feasible under biologically relevant conditions in any of these models. Then, I show that the transition can happen if one accounts for male heterogeneity, assortative pair formation, and evolution of female choice and faithfulness. This process is started when low-ranked males begin using an alternative strategy of female provisioning. At the end, except for the top-ranked individuals, males invest exclusively in provisioning females who have evolved very high fidelity to their mates. My results point to the crucial importance of female choice and emphasize the need for incorporating between-individual variation in theoretical and empirical studies of social dilemmas and behaviors.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2014

The mechanism of mass transfer was studied on a cellulose-based chiral stationary phase (CSP, Lux Cellulose-1) using aqueous mixtures of acetonitrile (50/50-90/10, v/v) or methanol (90/10 and 100/0, v/v) as the mobile phase. An experimental protocol validated in RPLC and HILIC chromatography and recently extended to chiral RPLC was applied. The five mass-transfer contributions (longitudinal diffusion, short-range and long-range eddy dispersion, solid-liquid mass transfer resistances due to finite intra-particle diffusivity and slow adsorption-desorption) to the reduced height equivalent to a theoretical plate (HETP) were measured. The experimental results show that the adsorption rate constants kads of trans-stilbene enantiomers onto the CSP are three times larger with acetonitrile than with methanol as the organic modifier. This is correlated to the decrease of enantioselectivity from 1.4 (in methanol) to only 1.1 (in acetonitrile). The amount of solvent needed to achieve a separation factor of exactly 2.0 was determined. This showed that analysis cost could be reduced seven times by selecting pure methanol as the eluent for a 5cm long column rather than an acetonitrile-water mixture for a longer (20-45cm) column. © 2013 Elsevier B.V.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2014

A rapid and simple validated experimental protocol is proposed for the accurate determination of the true intrinsic column efficiency and for that of the variance of the extra-column volume of the instrument used, the latter being obtained without requiring the removal of the chromatographic column from the HPLC system. This protocol was applied to 2.1mm×100mm columns packed with sub-3 (2.7μm Halo Peptide ES-C18) and sub-2μm (1.6μm prototype) core-shell particles. It was validated by observing the linear behavior of the plot of the apparent column plate height versus the reciprocal of (1+k')2 for at least three homologous compounds, with a linear regression coefficient R2 larger than 0.999. Irrespective of the contribution of the several, different instruments used to the total band broadening, the same column HETP value was obtained within 5%. This new protocol outperform the classical one in which the chromatographic column is replaced with a zero dead volume (ZDV) union connector to measure the extra-column volume variance, which is subtracted from the variance measured with the column to measure the intrinsic HETP. This protocol fails because it significantly underestimates the system volume variance. © 2013 Elsevier B.V.

Dagotto E.,University of Tennessee at Knoxville | Dagotto E.,Oak Ridge National Laboratory
Reviews of Modern Physics | Year: 2013

The iron-based superconductors that contain FeAs layers as the fundamental building block in the crystal structures have been rationalized in the past using ideas based on the Fermi surface nesting of hole and electron pockets when in the presence of weak Hubbard U interactions. This approach seemed appropriate considering the small values of the magnetic moments in the parent compounds and the clear evidence based on photoemission experiments of the required electron and hole pockets. However, recent results in the context of alkali metal iron selenides, with generic chemical composition A xFe2-ySe2 (A=alkali metal element), have challenged those previous ideas since at particular compositions y the low-temperature ground states are insulating and display antiferromagnetic order with large iron magnetic moments. Moreover, angle-resolved photoemission studies have revealed the absence of hole pockets at the Fermi level in these materials. The present status of this exciting area of research, with the potential to alter conceptually our understanding of the iron-based superconductors, is here reviewed, covering both experimental and theoretical investigations. Other recent related developments are also briefly reviewed, such as the study of selenide two-leg ladders and the discovery of superconductivity in a single layer of FeSe. The conceptual issues considered established for the alkali metal iron selenides, as well as several issues that still require further work, are discussed. © 2013 American Physical Society.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2014

The mechanism of mass transfer in chiral chromatography was investigated using an experimental protocol already applied in RPLC and HILIC chromatography. The different contributions to the reduced height equivalent to a theoretical plate (HETP) include the longitudinal diffusion HETP term, the solid-liquid mass transfer resistance HETP term, the short-range eddy dispersion HETP term, and the long-range eddy dispersion HETP term. Their accurate measurement permits the determination of the adsorption rate constant kads of trans-stilbene enantiomers on a column packed with Lux 5μm Cellulose-1 particles. The experimental results demonstrate that the number of adsorption-desorption steps per unit time of chiral compounds on polysaccharide-based chiral stationary phases is four orders of magnitude smaller than that of achiral compounds. © 2014 Elsevier B.V.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2014

The intrinsic heights equivalent to a theoretical plate (HETPs) of 31 narrow-bore and wide-bore columns packed with four different brands of core-shell particles were accurately measured on an optimized vHPLC instrument (1290 Infinity system) that has an extra-column volume variance of 13.6±0.3μL2. These results were derived from the slopes of the linear plots of the apparent plate heights of each column versus the reciprocal of (1+k')2 for seven homologous compounds with a linear regression coefficient larger than 0.999. The results show that the kinetic performance of narrow-bore columns packed with core-shell particles increases almost linearly with decreasing particle diameter. The optimum reduced plate heights increase slightly from 1.6 to 1.9 with decreasing particle sizes from 4.6 to 1.3μm. This confirms that wide-bore columns provide better efficiencies than narrow-bore columns. © 2014 Elsevier B.V.

Gilleaudeau G.J.,University of Tennessee at Knoxville | Kah L.C.,University of Tennessee at Knoxville
Chemical Geology | Year: 2013

Molybdenum is a bioessential micronutrient whose abundance in the global oceans may have played a primary role in evolution of the Earth's nitrogen cycle and, ultimately, in the timing of the ecologic expansion of early eukaryotes. Because molybdenum (Mo) is delivered to the ocean under conditions of oxic weathering and is removed in suboxic and euxinic environments, the concentration of Mo in the oceans reflects a complex function of global redox and the hydrologic conditions that influence the areal extent of euxinic sedimentation. Recent compilations of Mo within euxinic shales (. Scott et al., 2008; Och and Shields-Zhou, 2012; Sahoo et al., 2012) indicate that the oceanic reservoir of Mo did not rise substantially above crustal values until the Great Oxidation Event (~. 2.3. Ga), and a modern Mo cycle did not develop until the contraction of ocean euxinia in the latest Proterozoic.At present, a paucity of data from euxinic shales of the late Mesoproterozoic (1.3 to 1.0. Ga) limits our ability to relate marine redox evolution to biological innovation during a critical interval of eukaryotic development. Here we present data from marine shales of the 1.1. Ga Atar and El Mreiti groups, Mauritania, which were deposited during sea level highstand when shallow, epeiric seas covered much of the West African craton. Epicratonic strata of the El Mreiti Group were deposited under fluctuating redox conditions near a shallow chemocline (as evidenced by iron speciation), and record generally low Mo concentrations (<. 15. ppm) and Mo/TOC ratios (<. 2. ppm/wt.%), along with a weak covariance between Mo and TOC. By contrast, craton margin strata of the coeval Atar Group were deposited under relatively persistent euxinic conditions, yet record Mo concentrations largely <. 1. ppm and show no covariance between Mo and TOC. Combined, data suggest that Mo sourced from terrestrial weathering was preferentially sequestered in proximal regions of the epeiric sea, and that onshore sequestration led directly to critically low Mo concentrations in offshore waters. We suggest that a Mesoproterozoic expansion of nearshore euxinia (at least in pore waters) within epeiric seas led directly to a critical depletion of the global oceanic Mo reservoir. This hypothesis is supported by a series of first-order sensitivity tests that estimate the extent to which expansion of epeiric seas would have drawn down oceanic Mo concentrations. Ultimately, this study suggests that substantial lateral redox heterogeneity may have limited the availability of bioessential trace metals in the Mesoproterozoic oceans, despite evidence for increased biospheric oxygenation. Extreme Mo limitation in open oceans environments would have had profound effects on the global nitrogen cycle and may help explain observed onshore-offshore patterns in early eukaryotes. © 2013 Elsevier B.V.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2013

Kinetic Poppe plots for small retained compounds were calculated in HPLC (using pure acetonitrile) and SFC (using pure carbon dioxide) for columns having twenty one different lengths (between 3cm and 30m), operated under strict adiabatic conditions (no heat exchange was allowed between the column and the external environment), with a constant pressure drop of 200bar. The outlet pressures were set at 1 and 160bar in HPLC and SFC, respectively. The eluent inlet temperature was set at 312K. The hold-up time t0 and the apparent column efficiency 〈N〉 were calculated by taking into account the longitudinal variations of the eluent pressure, its temperature, density, viscosity, heat capacity, thermal expansion coefficient, equilibrium constant, and diffusion coefficient along the column length. Three different classes of stationary phase were considered: fully porous particles and core-shell particles of different diameter and structure, and silica monolithic columns of the second generation. The reduced plate heights of these stationary phases were taken from experimental data obtained with liquid eluents (acetonitrile/water mixtures). The columns were assumed to be radially homogeneous. The Henry's constant of the compound was fixed at Ka=2.0 at the column inlet. The results demonstrate the potential advantage of using sub-3μm core-shell particles for fast analysis in both LC and SFC, regardless of the intra-particle diffusivity through the stationary phase. In RPLC conditions, the contribution of surface diffusion to intra-particle diffusivity is important and the 4.6 μm core-shell particles can perform as well as sub-2 μm fully porous particles and silica monolithic columns of the second generation. In the absence of surface diffusion or for localized adsorption onto the stationary phase, sub-2 μm particles and silica monolithic column of the second generation outperform the 4.6 μm core-shell particles because the solid-liquid mass transfer resistance controls the column efficiency at high speeds. Eventually, for the same stationary phase and speed of analysis, SFC methods using pure CO2 may provide at least a twice column efficiency than LC methods using pure acetonitrile. For a constant pressure drop and resolution power, SFC methods may generate four times faster analyses than LC methods. Ultimately, a standard commercial 4.6mm × 50mm long column packed with 2.6μm core-shell particles, operated with an inlet flow rate of 25mL/min in fast SFC (200bar back pressure, 40°C) may provide a hold-up time of about 1s requiring data acquisition at a frequency of 400Hz, with a variance of 0.35μL2. This performance will require the use of new, ultra-low dispersion SFC system. © 2013 Elsevier B.V.

Zhu C.,University of Tennessee at Knoxville | Lu Z.P.,University of Science and Technology Beijing | Nieh T.G.,University of Tennessee at Knoxville
Acta Materialia | Year: 2013

Instrumented nanoindentation was conducted on a FeCoCrMnNi high-entropy alloy with a single face-centered cubic structure to characterize the nature of incipient plasticity. Experiments were carried out over loading rates of 25-2500 μN s-1 and at temperatures ranging from 22 to 150 °C. The maximum shear stress required to initiate plasticity was found to be within 1/15 to 1/10 of the shear modulus and relatively insensitive to grain orientation. However, it was strongly dependent upon the temperature, indicating a thermally activated process. Using a statistical model developed previously, both the activation volume and activation energy were evaluated and further compared with existing dislocation nucleation models. A mechanism consisting of a heterogeneous dislocation nucleation process with vacancy-like defects (∼3 atoms) as the rate-limiting nuclei appeared to be dominant. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Nolt J.,University of Tennessee at Knoxville
Climatic Change | Year: 2015

Climate change will cause large numbers of casualties, perhaps extending over thousands of years. Casualties have a clear moral significance that economic and other technical measures of harm tend to mask. They are, moreover, universally understood, whereas other measures of harm are not. Therefore, the harms of climate change should regularly be expressed in terms of casualties by such agencies such as IPCC’s Working Group III, in addition to whatever other measures are used. Casualty estimates should, furthermore, be used to derive estimates of casualties per emission source up to a given date. Such estimates would have wide margins of error, but they would add substantially to humanity’s grasp of the moral costs of particular greenhouse gas emissions. © 2014, Springer Science+Business Media Dordrecht.

Glisson C.,University of Tennessee at Knoxville | Hemmelgarn A.,University of Tennessee at Knoxville | Green P.,University of Tennessee at Knoxville | Williams N.J.,University of Tennessee at Knoxville
Journal of the American Academy of Child and Adolescent Psychiatry | Year: 2013

Objectives: The primary objective of the study was to assess whether the Availability, Responsiveness and Continuity (ARC) organizational intervention improved youth outcomes in community based mental health programs. The second objective was to assess whether programs with more improved organizational social contexts following the 18-month ARC intervention had better youth outcomes than programs with less improved social contexts. Method: Eighteen community mental health programs that serve youth between the ages of 5 and 18 were randomly assigned to ARC or control conditions. Clinicians (n = 154) in the participating programs completed the Organizational Social Context (OSC) measure at baseline and following the 18-month ARC organizational intervention. Caregivers of 393 youth who were served by the 18 programs (9 in ARC and 9 in control) completed the Shortform Assessment for Children (SAC) once a month for six months beginning at intake. Results: Hierarchical linear models (HLM) analyses indicated that youth outcomes were significantly better in the programs that completed the 18 month ARC intervention. HLM analyses also showed that youth outcomes were best in the programs with the most improved organizational social contexts following the 18 month ARC intervention. Conclusions: Youth outcomes in community mental health programs can be improved with the ARC organizational intervention and outcomes are best in programs that make the most improvements in organizational social context. The relationships linking ARC, organizational social context, and youth outcomes suggest that service improvement efforts will be more successful if those efforts include strategies to improve the organizational social contexts in which the services are embedded. © 2013 American Academy of Child and Adolescent Psychiatry.

Sharma M.,University of Tennessee at Knoxville
Applied Geography | Year: 2013

This study contributes to the literature on applied urban geography by examining spatial patterns and processes of changing racial/ethnic diversity within the intra-urban context of Knoxville metropolitan statistical area. Knoxville embraces a diverse economic set up with opportunities in high-tech research and development, manufacturing, tertiary/service-sectors, construction, as well as entertainment industry. This serves well for its continued population growth, including minorities during 1990-2009. This paper explores how the neighborhood-level socioeconomic, demographic, and built-environment characteristics relate to tract-level racial/ethnic diversity, measured by multi-group diversity score and its components. Tools such as isarithmic surface density maps, correlations, principal components and regression analyses are used to examine processes of change. Results indicate that diversity in 1990 associates with negative change whereas diversity in 2000 associates with positive change. Though overall diversity sprawls and increases during 1990-2009, diversity among non-White declines during 2000-2009 and shows spatial confinement. Regressions suggest complicated mosaics of changing neighborhoods, providing evidence of invasion-succession, filtering and resurgence of ethnic-enclaves in specific neighborhoods. Concerning the six counties of the MSA, Knox is the most diverse whereas Union the least, though the share of Hispanics tops in Loudon and Asians in Knox. In terms of strategic planning, findings from this research can be used in creating equitable and sustainable urban communities that can improve the overall well-being of people by reducing racial/ethnic and socio-economic disparities that might occur as undesirable consequences of fast increasing diversity. © 2013 The Author.

Twenty-five historical type collections of North American Russula species described by W.A. Murrill were sequenced and analyzed for placement in a phylogenetic and taxonomic framework. Molecular data was successfully obtained from sixteen type specimens (66%), of which eight species have never before been placed in an infrageneric classification system. Classifications and synonymization of taxa proposed by Rolf Singer and others are evaluated. Russula albimarginata and R. emeticiformis are suggested as synonyms of R. vinacea, a widespread and common species in the eastern United States. Four taxa of unknown classification (R. albimarginata, R. pinophila, R. subcremeiceps, R. subrubescens) have been classified to subsection level, and an alternative classification is proposed for R. westii. A morphological comparison of a collection from British Columbia (Canada) with 99% sequence similarity to R. levyana in the Internal Transcribed Spacer 1 (ITS1) region indicates that this region alone may be inadequate for species barcoding in Russula. © 2014. Mycotaxon, Ltd.

Floden A.,University of Tennessee at Knoxville
Annales Botanici Fennici | Year: 2014

Heteropolygonatum urceolatum J.M.H. Shaw (Asparagaceae), is transferred to Polygonatum based on morphological and cytological evidence. Polygonatum mengtzense F.T. Wang and T. Tang is reinstated to specific status and its description amended based on examination of ample living and herbarium material. Chromosome counts and karyotypes are presented for both species that provide evidence that the two are most closely related to the Himalayan P. punctatum. Data on their distribution and habitat are provided. A key morphological trait of Heteropolygonatum, terminal inflorescences, is discussed in relation to the generic value of this character and shown not to be diagnostic. © 2014 Finnish Zoological and Botanical Publishing Board.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2014

Highlights: Whether columns packed with core-shell particles may outperform those packed with fully porous particles for chiral separations is controversial. The potential advantages of such columns are investigated from a theoretical viewpoint. The height equivalent to a theoretical plate (HETP) associated to the slow adsorption-desorption process typical of chiral chromatography was derived from the Laplace transform of the general rate model of chromatography for core-shell particles. The relationship between the resolution factor and the core-to-particle diameter ratio is predicted at constant selectivity. The calculations are based on a complete set of actual kinetic parameters (longitudinal diffusion, eddy dispersion, intra-particle diffusivity, and adsorption-desorption constant) measured for a reference column packed with Lux Cellulose-1 fully porous particles. If we compare columns packed with the best procedure available in either case, the results demonstrate that those packed with core-shell particles may outperform to a degree those packed with fully porous particles. The minimum reduced HETP could decrease from 2.0 to 1.7. The maximum relative gain in resolution is about 10%, which is not negligible for critical enantioselective-separations. This gain is observed only if the packing uniformity of the core-shell particles is achieved. © 2014 Elsevier B.V.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2014

Severe distortions of the axial concentration profiles of modifiers in steep RPLC gradients were recently observed. These distortions are directly explained by the results of measurements of the excess adsorption isotherms of the strongest mobile phase component, the concentration of which is made to increase linearly with time at the column inlet. A front shock or a discontinuity of the organic modifier concentration may arise and grow along the column. The position where it forms is determined by the reciprocal of the second derivative of the excess adsorption isotherm with respect to the concentration of the strongest mobile phase component. It forms when two characteristic lines intersect for the first time. Gradient profiles are continuous and diffuse as long as characteristic lines do not intersect but diverge from each other. However, acetonitrile-water gradients are systematically distorted and deviate significantly from assumed ideal, linear, non-retained gradients. This challenges the validity of classical theories of gradient chromatography regarding the prediction of retention times, peak widths, and band compression factors when steep gradients are applied. © 2014 Elsevier B.V.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2014

In a previous report, it was reported that columns packed with fully porous 1.9μm Titan-C18 particles provided a minimum reduced plate height as small as 1.7 for the most retained compound (n-octanophenone) under RPLC conditions. These particles are characterized by a relatively narrow size distribution with a relative standard deviation (RSD) of only 10%. A column packed with classical 5μm Symmetry-C18 particles, used as a reference RPLC column, generated a minimum reduced plate height of 2.1 for the same retained compound. This work demonstrates that this was due to an unusually low intra-particle diffusivity across these particles, which leads to a small longitudinal diffusion coefficient along the column. The demonstration is based on the combination of accurate measurements of the height equivalent to a theoretical plate (HETP), inverse size exclusion chromatography (ISEC), peak parking (PP), and minor disturbance method (MDM) experiments.The experimental results show that the reduced eddy dispersion HETP term (A=0.8 for a reduced velocity of 5), the internal particle porosity (εp=0.35), and the enrichment of acetonitrile in the pore volume (75% acetonitrile in the bulk, 85% inside the mesoporous volume) are identical on both the Titan-C18 and Symmetry-C18 columns. The difference between the internal structures of these two brands of RPLC-C18 fully porous particles lies in the values of the internal obstruction factor γp, which is 0.42 for the Symmetry-C18 but only 0.26 for the Titan-C18 particles. This is in part related to the diffusion hindrance due to the small average pore size of the Titan-C18 particles, around 59Å versus 77Å for Symmetry-C18 particles. A simple model of constriction along diffusion paths having the shape of a truncated cone suggests that the width of the pore size distribution (RSD of 30% and 20% for Titan-C18 and Symmetry-C18 particles) is mostly responsible for the difference in their obstruction factors. © 2014 Elsevier B.V.

Scheitlin K.,University of Tennessee at Knoxville
Earth Interactions | Year: 2013

This study analyzes the influence of the Atlantic Ocean and Chesapeake Bay on the diurnal temperature range (DTR) reported by nearby weather stations. Coastal locations reported the smallest DTRs and DTR fluctuations, and DTR increased with distance from the ocean. Month of the year and airmass type also proved to be significant predictors of DTR. All locations showed a bimodal annual DTR pattern with peaks during the transitional seasons and experienced the greatest DTR during dry and/or warm air masses. Proximity to the ocean had the largest (smallest) influence on DTR during dry (moist) air masses with extreme (moderate) temperatures. Seasonally, the proximity to the ocean had the strongest impact on DTR during early-middle spring. A multiple regression model using distance from water, month, and airmass type explains over 30% of DTR variability in the area (p 0.01). Airmass type has the largest influence on DTR, and changes in both air mass and month impacted the DTR of continental locations more than coastal locations. Land use, cloud cover, and wind speed/direction are additional variables that could account for differences not explained by the model. ©2013.

Juslin N.,University of Tennessee at Knoxville | Wirth B.D.,University of Tennessee at Knoxville
Journal of Nuclear Materials | Year: 2013

Nanometer-sized bubbles in tungsten containing various concentrations of helium and/or hydrogen gas were studied using molecular dynamics simulations. Bubbles of different sizes and compositions were relaxed and evolved at temperatures from 300 K to 2100 K. Helium atoms are evenly distributed inside the bubble at all temperatures, while the hydrogen tends to diffuse to the bubble periphery. In all cases a large amount of hydrogen is bound within the first 1-2 layers of the tungsten matrix surrounding the bubble, though clear dependencies on temperature and bubble composition were found. © 2013 Elsevier B.V. All rights reserved.

Perez-Garcia M.A.,University of Salamanca | Silk J.,University of Oxford | Stone J.R.,University of Oxford | Stone J.R.,University of Tennessee at Knoxville
Physical Review Letters | Year: 2010

We show that self-annihilating weakly interacting massive particle (WIMP) dark matter accreted onto neutron stars may provide a mechanism to seed compact objects with long-lived lumps of strange quark matter, or strangelets, for WIMP masses above a few GeV. This effect may trigger a conversion of most of the star into a strange star. We use an energy estimate for the long-lived strangelet based on the Fermi-gas model combined with the MIT bag model to set a new limit on the possible values of the WIMP mass that can be especially relevant for subdominant species of massive neutralinos. © 2010 The American Physical Society.

Salafranca J.,University of Tennessee at Knoxville | Salafranca J.,Oak Ridge National Laboratory | Okamoto S.,Oak Ridge National Laboratory
Physical Review Letters | Year: 2010

The proximity effect in a model manganite-cuprate system is investigated theoretically. We consider a situation in which spin-polarized electrons in manganite layers antiferromagnetically couple with electrons in cuprate layers as observed experimentally. The effect of the interfacial magnetic coupling is found to be much stronger than the injection of spin-polarized electrons into the cuprate region. As a result, the superconducting transition temperature depends on the thickness of the cuprate layer significantly. Since the magnetic coupling creates negative polarization, an applied magnetic field and the negative polarization compete, resulting in the inverse spin-switch behavior where the superconducting transition temperature is increased by applying a magnetic field. © 2010 The American Physical Society.

Fitzpatrick B.M.,University of Tennessee at Knoxville
Ecology and Evolution | Year: 2013

Understanding factors regulating hybrid fitness and gene exchange is a major research challenge for evolutionary biology. Genomic cline analysis has been used to evaluate alternative patterns of introgression, but only two models have been used widely and the approach has generally lacked a hypothesis testing framework for distinguishing effects of selection and drift. I propose two alternative cline models, implement multivariate outlier detection to identify markers associated with hybrid fitness, and simulate hybrid zone dynamics to evaluate the signatures of different modes of selection. Analysis of simulated data shows that previous approaches are prone to false positives (multinomial regression) or relatively insensitive to outlier loci affected by selection (Barton's concordance). The new, theory-based logit-logistic cline model is generally best at detecting loci affecting hybrid fitness. Although some generalizations can be made about different modes of selection, there is no one-to-one correspondence between pattern and process. These new methods will enhance our ability to extract important information about the genetics of reproductive isolation and hybrid fitness. However, much remains to be done to relate statistical patterns to particular evolutionary processes. The methods described here are implemented in a freely available package "HIest" for the R statistical software (CRAN; © 2013 The Authors. Ecology and Evolution.

Simberloff D.,University of Tennessee at Knoxville | Vitule J.R.S.,Federal University of Paraná
Oikos | Year: 2014

Calls for the end of invasion biology are misguided. There is no evidence that modern invasion biology has progressed slowly in its short life. Although some aspects of biological invasions fit comfortably in the framework of ecological succession, many others do not. Some native species, particularly in the wake of various anthropogenic impacts, behave like invasive non-native species, but the probability and degree of harmful impact are greater for non-native than for native species. Neither native nor non-native species suffer lack of attention and research by virtue of the fact that invasion biology focuses on the latter. Basing management solely on current observed impact is highly risky because impacts may be subtle but nonetheless important, and impacts often change, as they are contingent on the physical or biotic environment. The known harmful impacts of many non-native species suggest that recent introductions warrant attention even if impacts are not evident. Neither is the focus of modern invasion biology on non-native species motivated by xenophobia. Rather, it reflects the recognition of their likelihood of harmful impact. A related call for the end of traditional restoration ecology shares many features with calls to terminate invasion biology, not least because management of invasive non-native species is a key component of restoration ecology. Such species are a dominant element in generating the 'novel ecosystems' that are said to render traditional restoration ecology obsolete. The argument that both invasion management and traditional restoration are largely futile endeavors is contradicted by substantial and growing successes in both fields. © 2013 The Authors.

The niche is one of the most important concepts in ecology. However, there has been a persistent controversy on how to define, measure, and predict the ecological niche of an organism. Here I argue that these problems arise in part because the niche is defined by the set of all possible environments, many of which do not exist in nature. A complete description of the niche would require knowledge of a large number of environments that do not exist in nature. Given this, I propose that ecologists should not focus on the niche itself but instead on determining if a particular environment is a part of the niche. I then demonstrate that such an analysis has a natural interpretation as an estimate of the probability that an environment is suitable and that either experimental investigations or analyses of presence data can estimate this quantity. Depending on the way that resources interact to shape environmental requirements, the probability that an environment is a part of the niche behaves like published descriptions of causal inferences and distribution models. However, in some cases the probability that an environment is suitable can be strongly influenced by unmeasured aspects of the environment. When this is true, experimental and distribution models have complimentary strengths and weaknesses. © 2009 Oikos.

Moghani M.M.,University of Tennessee at Knoxville | Khomami B.,University of Tennessee at Knoxville
Soft Matter | Year: 2013

Experimental studies on nano- and micrometer sized Janus particles (JPs) have demonstrated a plethora of simple and complex self-assembled structures. In this study, molecular dynamics simulations that include long range Coulombic interaction have been utilized to elucidate the underlying physics of self-assembly of nano-scale spherical bipolar JPs as a function of surface charge density, salt concentration and particle size. Specifically, two distinct sub-structures at low JP concentration, namely, strings and rings have been identified. As the concentration of JPs is increased these sub-structures join and/or hierarchically assemble into larger porous clusters. Moreover, it has been demonstrated that surface charge defects lead to precipitous loss of directional self-assembly. Finally, a direct connection between the ionic cloud around a single JP and the self-assembled structure morphology has been demonstrated. Overall, the results of this study should pave the way for future coordinated experimental/computational studies towards development of a mechanistic understanding of morphology development in this class of material. © 2013 The Royal Society of Chemistry.

Lelu M.,University of Tennessee at Knoxville
Proceedings. Biological sciences / The Royal Society | Year: 2013

Parasites with complex life cycles are expected to manipulate the behaviour of their intermediate hosts (IHs), which increase their predation rate and facilitate the transmission to definitive hosts (DHs). This ability, however, is a double-edged sword when the parasite can also be transmitted vertically in the IH. In this situation, as the manipulation of the IH behaviour increases the IH death rate, it conflicts with vertical transmission, which requires healthy and reproducing IHs. The protozoan Toxoplasma gondii, a widespread pathogen, combines both trophic and vertical transmission strategies. Is parasite manipulation of host behaviour still adaptive in this situation? We model the evolution of the IH manipulation by T. gondii to study the conflict between these two routes of transmission under different epidemiological situations. Model outputs show that manipulation is particularly advantageous for virulent strains and in epidemic situations, and that different levels of manipulation may evolve depending on the sex of the IH and the transmission routes considered. These results may help to understand the variability of strain characteristics encountered for T. gondii and may extend to other trophically transmitted parasites.

Sanders N.J.,University of Tennessee at Knoxville
Molecular Ecology | Year: 2010

What allows some species to successfully colonize a novel environment while others fail? Numerous studies in invasion biology have sought to answer this question, but those studies have tended to focus on traits of species or individuals (e.g. body size, seed size, seed number), and these traits have largely been found to be weak predictors of invasion success. However, characteristics of colonizing populations (e.g. genetic diversity, density, age structure) might also be important for successful establishment, as the authors of a study published in this issue of Molecular Ecology show (Crawford & Whitney 2010). By experimentally manipulating the density and genetic diversity of colonizing populations of Arabidopsis thaliana, the authors found that genetic diversity, but not population density, increased colonization success. Importantly, the effects of genetic diversity on colonization success were both additive and non-additive, suggesting that traits associated with particular genotypes and complimentarity among genotypes contribute to colonization success. This research highlights the importance of considering within-species variation and characteristics of entire populations in predicting colonization success. © 2010 Blackwell Publishing Ltd.

Zuo L.,University of Tennessee at Knoxville | Islam S.K.,University of Tennessee at Knoxville
IEEE Transactions on Circuits and Systems I: Regular Papers | Year: 2013

This paper presents two low-voltage bulk-driven amplifier input stages with enhanced transconductance. The idea is to introduce auxiliary differential pairs into a conventional bulk-driven stage to boost its transconductance. A low-voltage cascode biasing circuitry based on EKV models is also employed to ensure proper operation of the proposed input stages. An operational amplifier is then implemented with the proposed input stages and biasing circuits as its core building blocks and including a modified low-voltage class AB output amplifier to guarantee rail-to-rail output voltage range. The overall amplifier was implemented in a 0.35 μ m n-well CMOS process using 1-V power supply. The measurement results show significant improvement in the performance of the operational amplifier compared to prior arts. © 2004-2012 IEEE.

Mazur P.,University of Tennessee at Knoxville
Cryobiology | Year: 2010

Thermodynamics and physical chemistry have played powerful roles the past 45 years in interpreting cryobiological problems and in predicting cryobiological outcomes. The author has been guided by a few core principles in using these concepts and tools and this paper discusses these core principles. They are (1) the importance of chemical potentials and of the difference between the chemical potentials of water and solutes inside the cell and outside in determining the direction and rate of fluxes of water and solutes. (2) The influence of the curvature of an ice crystal on its chemical potential and on the ability of ice to pass through pores in cell membranes, on the nucleation temperature of supercooled water, and on the recrystallization of ice. (3) The use of Le Chatalier's Principle in qualitatively predicting the direction of a reaction in response to variables like pressure. (4) The fact that the energy differences between State A and State B are independent of the path taken to go from A to B. (5) The importance of being aware of the assumptions underlying thermodynamic models of cryobiological events. And (6), the difficulties in obtaining experimental verification of thermodynamic and physical-chemical models. © 2009 Elsevier Inc. All rights reserved.

Wang Y.,University of Tennessee at Knoxville | Choo H.,University of Tennessee at Knoxville
Acta Materialia | Year: 2014

The influence of changes in crystallographic texture on the Hall-Petch (H-P) relationship for an Mg alloy was investigated. First, the texture variations were facilitated by changing the uniaxial tensile loading orientation with respect to the normal direction of the rolled Mg plate. With a strong plane texture of the as-received material, the initial dominant deformation mechanisms were systematically varied from the basal slip and prismatic slip to extension twinning, as well as combinations thereof. Second, different grain sizes were produced for each loading orientation through isochronal annealing at various temperatures up to 773 K while closely monitoring grain size and texture distributions. The experimental results are presented for the grain growth kinetics during annealing, changes in yielding behavior as a function of grain size and initial texture, and H-P relationship as a function of the texture. Moreover, the effects of changes in texture and dominant deformation mechanism on H-P parameters - namely, friction stress, σo, and strength coefficient, kσ- are discussed. Finally, H-P relationships for each individual deformation mode including basal, prismatic and pyramidal slips as well as extension twin are identified.

Li H.,University of Tennessee at Knoxville | Han Z.,University of Houston
IEEE Transactions on Wireless Communications | Year: 2011

The main challenge to cognitive radio is the emergence of primary users, which can be considered as the service interruptions in a queuing system. The service interruption can incur significant delays for secondary users' data packets which are considered as secondary customers. Therefore, a secondary customer needs to decide whether to join the queue or leave for other means of transmission. It is shown that the individually optimal strategy for joining the queue is characterized by a threshold of queue length. When the current queue length is above this threshold, the secondary customer should leave; otherwise it should join the queue. The socially optimal threshold of queue length is also obtained and is numerically shown to be smaller than the individually optimal one, which implies that the individually optimal strategy does not yield the socially optimal one. To bridge the gap between the individually and socially optimal strategies, a pricing mechanism is proposed to toll the service of each secondary customer, thus equalizing the two optimal strategies. When the channel statistics are unknown, an online learning procedure, based on the Kiefer-Wolfowitz algorithm, is proposed. The proposed algorithms are then demonstrated using numerical simulations. © 2011 IEEE.

Vogt F.,University of Tennessee at Knoxville
Journal of Chemometrics | Year: 2014

Assessing current trends in chemometric publications reveals that most projects utilize known methodologies and fall into the category "application." There seems to be worrying little of true innovation unless one counts "fashions" assimilated from other fields. The field may have reached a crossroad: One path leads to chemometrics becoming a fully mature but stagnant tool for analytical chemists; the other path, that is, maintaining chemometrics as an active and widely recognized research field, requires opening new research areas for chemometricians. It is argued that hard modeling as opposed to the ubiquitous soft modeling may become such a new direction. Hard modeling would focus on investigating chemical mechanisms that give raise to measured data as opposed to empirically analyzing data.Furthermore, chemometricians in academia are responsible for preparing the next generation of chemometricians. Despite the need for chemometricians in the workforce, the number of young chemometricians is low and will remain low unless changes in chemistry curricula happen. This remains a challenge because there are fundamental issues that need to be overcome. © 2014 John Wiley & Sons, Ltd.

Crosnoe L.E.,University of Tennessee at Knoxville | Kim E.D.,University of Tennessee at Knoxville
Current Opinion in Obstetrics and Gynecology | Year: 2013

PURPOSE OF REVIEW: An increasing number of older men are seeking help for fathering a child, but male fertility gradually declines with age. This review highlights changes in male reproductive biology and practical clinical concerns for aging men. RECENT FINDINGS: Aging may have an impact on sperm DNA damage such as single nucleotide polymorphisms. A recent landmark study identified that the number of single gene de-novo mutations in the offspring increased by two mutations per year based on paternal age. Additionally, advanced paternal age has been linked with neurocognitive disorders such as autism and schizophrenia. For the management of hypogonadism, strategies using selective estrogen modulators have been increasingly utilized to maintain fertility potential. SUMMARY: Aging has an impact on male fertility potential, as well as potential genetic effects for the offspring. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Cihak D.F.,University of Tennessee at Knoxville
Research in Autism Spectrum Disorders | Year: 2010

This study evaluated the differential effects of two different visual schedule strategies. In the context of an alternating treatments design, static-picture schedules were compared to video based activity schedules as supports for three middle school aged students with autism. Students used the visual schedules to transition between activities in their classroom. All participants began transition more independently after being exposed to the visual schedules. Two participants reached criteria faster with static-picture schedules while the third participant made slightly faster progress with the video based schedule. The positive outcomes for both interventions are discussed in the context of practitioners' need for a variety of evidenced based practices to meet the needs of a diverse student body as well and that similar interventions may have different outcomes depending on the characteristics and preferences of the learner. © 2011 Elsevier Ltd. All rights reserved.

Shah P.,University of Tennessee at Knoxville | Gilchrist M.A.,University of Tennessee at Knoxville
PLoS Genetics | Year: 2010

Despite the fact that tRNA abundances are thought to play a major role in determining translation error rates, their distribution across the genetic code and the resulting implications have received little attention. In general, studies of codon usage bias (CUB) assume that codons with higher tRNA abundance have lower missense error rates. Using a model of protein translation based on tRNA competition and intra-ribosomal kinetics, we show that this assumption can be violated when tRNA abundances are positively correlated across the genetic code. Examining the distribution of tRNA abundances across 73 bacterial genomes from 20 different genera, we find a consistent positive correlation between tRNA abundances across the genetic code. This work challenges one of the fundamental assumptions made in over 30 years of research on CUB that codons with higher tRNA abundances have lower missense error rates and that missense errors are the primary selective force responsible for CUB. © 2010 Shah, Gilchrist.

Yan R.,University of Tennessee at Knoxville | McKee B.D.,University of Tennessee at Knoxville
PLoS Genetics | Year: 2013

Cohesion between sister chromatids is mediated by cohesin and is essential for proper meiotic segregation of both sister chromatids and homologs. solo encodes a Drosophila meiosis-specific cohesion protein with no apparent sequence homology to cohesins that is required in male meiosis for centromere cohesion, proper orientation of sister centromeres and centromere enrichment of the cohesin subunit SMC1. In this study, we show that solo is involved in multiple aspects of meiosis in female Drosophila. Null mutations in solo caused the following phenotypes: 1) high frequencies of homolog and sister chromatid nondisjunction (NDJ) and sharply reduced frequencies of homolog exchange; 2) reduced transmission of a ring-X chromosome, an indicator of elevated frequencies of sister chromatid exchange (SCE); 3) premature loss of centromere pairing and cohesion during prophase I, as indicated by elevated foci counts of the centromere protein CID; 4) instability of the lateral elements (LE)s and central regions of synaptonemal complexes (SCs), as indicated by fragmented and spotty staining of the chromosome core/LE component SMC1 and the transverse filament protein C(3)G, respectively, at all stages of pachytene. SOLO and SMC1 are both enriched on centromeres throughout prophase I, co-align along the lateral elements of SCs and reciprocally co-immunoprecipitate from ovarian protein extracts. Our studies demonstrate that SOLO is closely associated with meiotic cohesin and required both for enrichment of cohesin on centromeres and stable assembly of cohesin into chromosome cores. These events underlie and are required for stable cohesion of centromeres, synapsis of homologous chromosomes, and a recombination mechanism that suppresses SCE to preferentially generate homolog crossovers (homolog bias). We propose that SOLO is a subunit of a specialized meiotic cohesin complex that mediates both centromeric and axial arm cohesion and promotes homolog bias as a component of chromosome cores. © 2013 Yan, McKee.

West D.R.,University of Tennessee at Knoxville | Kincer D.R.,University of Tennessee at Knoxville
Biomass and Bioenergy | Year: 2011

A bio-refinery to produce ethanol from switchgrass (Panicum virgatum L.) and corn cobs (Zea mays L.) opened in January 2009 in Monroe County Tennessee, USA, and contracts have been awarded to farmers within an 80 km area to produce switchgrass as a biofuel feedstock. This research was undertaken to provide information about seeding rates and dates for a projected 4000 ha of switchgrass production. The experimental treatments were seeding rates of 4.48, 6.72, 8.96, and 11.2 kg ha-1 of pure live seed (PLS) and seeding dates at two week intervals on April 23, May 7, May 21, and June 4, in 2007. The seeding rate of 4.48 kg ha-1 produced lower yields of dry matter than the other seeding rates during the establishment year (4.69 vs 6.42 Mg ha-1). There were no differences in yield among seeding rates in the second through the fourth year of production. The early seeding dates of April 23 and May 7 produced lower yields than the May 21 and June 4 seeding dates in each of the first three years of production. In the fourth year of production, yield from the first planting date was equal to the third and fourth planting dates. © 2011 Elsevier Ltd.

Gottesfeld P.,Occupational Knowledge International | Cherry C.R.,University of Tennessee at Knoxville
Energy Policy | Year: 2011

China and India are embarking on ambitious initiatives over the next decade to expand solar photovoltaic (PV) power in underserved regions. China proposes adding 1.6. GW of solar capacity by 2020, while India plans 12. GW in addition to 20 million solar lanterns by 2022. These technologies rely heavily on lead-acid batteries (LABs) for storage. China and India's lead mining, battery production, and recycling industries are relatively inefficient-33% and 22% environmental loss rates, respectively. Based on the quantity of lead batteries employed in existing PV systems, we estimate environmental lead emissions in China and India for new units installed under their solar energy goals. The average loss rates are 12. kg (China) and 8.5. kg (India) of lead lost per kW-year of installed PV capacity in these countries. The planned systems added in China and India will be responsible for 386 and 2030. kt of environmental lead loss, respectively, over their lifespan-equal to 1/3 of global lead production in 2009. Investments in environmental controls in lead smelting, battery manufacturing, and recycling industries along with improvements in battery take-back policies should complement deployment of solar PV systems to mitigate negative impacts of lead pollution. © 2011 Elsevier Ltd.

Zhao Z.,University of Tennessee at Knoxville | Li X.,University of Tennessee at Knoxville
Operations Research for Health Care | Year: 2014

The problem studied in this paper is to schedule elective surgeries (in contrast to urgent surgeries) to multiple operating rooms (ORs) in ambulatory surgical settings. We focus on three aspects of the daily scheduling decisions, including the number of ORs to open, the allocation of surgery-to-OR, and the sequence of surgeries in each OR. All the surgeries to be scheduled are known in advance, which is a common assumption for elective surgery scheduling problems. The surgeries belong to different types, and each OR can only allow certain types of surgeries to be performed. Before a surgery starts, some setup work needs to be done, such as sterilization and preparing required equipment. The setup times are assumed sequence-dependent, and both setup times and surgery durations are deterministic. The fixed costs of running the ORs are high; while sometimes overtime costs, which are even higher than the fixed costs, may occur when the surgeries cannot be done within the normal operating period of the ORs. We build a Mixed Integer Nonlinear Programming (MINLP) model and a Constraint Programming (CP) model to solve this problem. The performance of these two models is tested on numerical examples, and the results show that the CP model is more efficient than the MINLP model in terms of the computational time and solution quality. We also examine the sensitivity of the solutions to the variation of surgery durations, and the analysis shows that the total costs do not change much when the variations of surgery durations are small. © 2014 Elsevier Ltd.

Geographic variation in body size is of special interest because it affects nearly all aspects of an organism's life. I examined whether differences in body size among four populations of the green anole lizard, Anolis carolinensis, were attributable to maternal investment in egg size and/or growth rates of embryos and juveniles. Larger body size and larger egg size relative to female size in the northern part of the range have been documented in this species, and suggested to be adaptive responses to more extreme winters. The current study confirmed the trends in adult size and egg size in the north, but rejected the trend of larger egg size relative to body size in the south. To control for differences in maternal investment in egg size among populations, I performed yolk removals on eggs from two northern populations to produce comparably sized eggs relative to one southern population. This manipulation was designed to minimize the confounding effect of maternal investment in yolk, the primary energy reserves for eggs, so that intrinsic differences in embryonic growth due to metabolism could be investigated. I found that differences in juvenile and, potentially, embryonic growth rates existed among populations of A. carolinensis, both due to and independent of differences in egg size. Juveniles from the northernmost population were bigger not only due to larger egg size, but also due to faster juvenile growth and possibly differences in developmental stage of oviposition or conversion of egg mass to hatchling mass. Larger body size may hold a number of advantages in northern populations of this species, including starvation resistance through winters and better competitive access to food resources and warmer microhabitats. © The Society of Population Ecology and Springer 2009.

Gavrilets S.,University of Tennessee at Knoxville
PLoS computational biology | Year: 2010

A crucial step in several major evolutionary transitions is the division of labor between components of the emerging higher-level evolutionary unit. Examples include the separation of germ and soma in simple multicellular organisms, appearance of multiple cell types and organs in more complex organisms, and emergence of casts in eusocial insects. How the division of labor was achieved in the face of selfishness of lower-level units is controversial. I present a simple mathematical model describing the evolutionary emergence of the division of labor via developmental plasticity starting with a colony of undifferentiated cells and ending with completely differentiated multicellular organisms. I explore how the plausibility and the dynamics of the division of labor depend on its fitness advantage, mutation rate, costs of developmental plasticity, and the colony size. The model shows that the transition to differentiated multicellularity, which has happened many times in the history of life, can be achieved relatively easily. My approach is expandable in a number of directions including the emergence of multiple cell types, complex organs, or casts of eusocial insects.

Gavrilets S.,University of Tennessee at Knoxville
PLoS Computational Biology | Year: 2010

A crucial step in several major evolutionary transitions is the division of labor between components of the emerging higherlevel evolutionary unit. Examples include the separation of germ and soma in simple multicellular organisms, appearance of multiple cell types and organs in more complex organisms, and emergence of casts in eusocial insects. How the division of labor was achieved in the face of selfishness of lower-level units is controversial. I present a simple mathematical model describing the evolutionary emergence of the division of labor via developmental plasticity starting with a colony of undifferentiated cells and ending with completely differentiated multicellular organisms. I explore how the plausibility and the dynamics of the division of labor depend on its fitness advantage, mutation rate, costs of developmental plasticity, and the colony size. The model shows that the transition to differentiated multicellularity, which has happened many times in the history of life, can be achieved relatively easily. My approach is expandable in a number of directions including the emergence of multiple cell types, complex organs, or casts of eusocial insects. © 2010 Sergey Gavrilets.

Sun X.,Oak Ridge National Laboratory | Sun X.,CAS Changchun Institute of Applied Chemistry | Luo H.,Oak Ridge National Laboratory | Dai S.,Oak Ridge National Laboratory | Dai S.,University of Tennessee at Knoxville
Chemical Reviews | Year: 2012

A study was conducted to demonstrate that ionic liquids-based extraction had emerged as a potential strategy for the advanced nuclear fuel cycle (NFC). The advanced NFC maximized fuel resource utilization, reduced the volume and toxicity of nuclear waste, facilitated handling and transportation, and saved on geological repository costs. Room-temperature ionic liquids (ILs), a novel type of solvent, showed significant potential as a separation technology for the advanced NFC. Room-temperature ionic liquids were defined as room-temperature molten salts, which were composed of cations and anions, and their melting points were below 100 °C. The ILs gained significance for their preparation, purification, physicochemical properties, solvation environment, partitioning behavior, and extraction mechanism, along with strategies for improvement and a forecast of IL-based extraction from the viewpoint of promising technologies for the advanced NFC.

Karpinets T.V.,Oak Ridge National Laboratory | Karpinets T.V.,University of Tennessee at Knoxville | Park B.H.,Oak Ridge National Laboratory | Uberbacher E.C.,Oak Ridge National Laboratory
Nucleic Acids Research | Year: 2012

Due to advances in high-throughput biotechnologies biological information is being collected in databases at an amazing rate, requiring novel computational approaches that process collected data into new knowledge in a timely manner. In this study, we propose a computational framework for discovering modular structure, relationships and regularities in complex data. The framework utilizes a semantic-preserving vocabulary to convert records of biological annotations of an object, such as an organism, gene, chemical or sequence, into networks (Anets) of the associated annotations. An association between a pair of annotations in an Anet is determined by the similarity of their co-occurrence pattern with all other annotations in the data. This feature captures associations between annotations that do not necessarily co-occur with each other and facilitates discovery of the most significant relationships in the collected data through clustering and visualization of the Anet. To demonstrate this approach, we applied the framework to the analysis of metadata from the Genomes OnLine Database and produced a biological map of sequenced prokaryotic organisms with three major clusters of metadata that represent pathogens, environmental isolates and plant symbionts. © 2012 The Author(s).

Twardosz S.,University of Tennessee at Knoxville | Lutzker J.R.,Georgia State University
Aggression and Violent Behavior | Year: 2010

In this article we review neuroscience perspectives on child maltreatment to facilitate understanding of the rapid integration of neuroscience knowledge into the academic, clinical, and lay literature on this topic. Seminal articles from developmental psychology and psychiatry, a discussion of brain plasticity, and a summary of recent reviews of research on stress system dysregulation are presented with some attention to methodological issues. A common theme is that maltreatment during childhood is an experience that may affect the course of brain development, potentially leading to differences in brain anatomy and functioning with lifelong consequences for mental health. The design of prevention and intervention strategies for child maltreatment may benefit from considering neuroscience perspectives along with those of other disciplines. © 2009 Elsevier Ltd. All rights reserved.

Reynolds G.D.,University of Tennessee at Knoxville
Behavioural Brain Research | Year: 2015

This paper explores the role visual attention plays in the recognition of objects in infancy. Research and theory on the development of infant attention and recognition memory are reviewed in three major sections. The first section reviews some of the major findings and theory emerging from a rich tradition of behavioral research utilizing preferential looking tasks to examine visual attention and recognition memory in infancy. The second section examines research utilizing neural measures of attention and object recognition in infancy as well as research on brain-behavior relations in the early development of attention and recognition memory. The third section addresses potential areas of the brain involved in infant object recognition and visual attention. An integrated synthesis of some of the existing models of the development of visual attention is presented which may account for the observed changes in behavioral and neural measures of visual attention and object recognition that occur across infancy. © 2015 Elsevier B.V.

Liu G.,University of Tennessee at Knoxville | Zhong Q.,University of Tennessee at Knoxville
Food Hydrocolloids | Year: 2013

Aggregation of whey proteins during thermal processing is a challenge to maintain the dispersibility, particularly at pH near isoelectric point and increased ionic strength. We report glycation of whey protein isolate (WPI) with lactose and maltodextrin enabled transparent dispersions after heating at 88 °C for 2 min, when tested at 7%w/v protein, pH 3.0-7.0 and 0-150 mM NaCl or CaCl2. Transparent dispersions corresponded to particles smaller than 14 nm based on atomic force microscopy. In comparison, WPI glycated with glucose behaved similarly to WPI control, forming turbid dispersions or gels at many conditions. Based on analytical ultracentrifugation, reducing saccharide with a smaller molecular weight was glycated at a larger number on each protein molecule, agreeing with changes in amino acid composition. Glycation lowered the isoelectric point and increased denaturation temperatures of WPI. The results suggest that repulsive steric interactions are the dominant mechanism controlling whey protein aggregation and thus transparency of dispersions. © 2012 Elsevier Ltd.

Choi S.H.,University of Tennessee at Knoxville
Journal of Aging and Health | Year: 2012

Objectives: This study tested a healthy immigrant effect (HIE) and postimmigration health status changes among late life immigrants. Methods: Using three waves of the Second Longitudinal Study of Aging (1994-2000) and the linked mortality file through 2006, this study compared (a) chronic health conditions, (b) longitudinal trajectories of self-rated health, (c) longitudinal trajectories of functional impairments, and (d) mortality between three groups (age 70+): (i) late life immigrants with less than 15 years in the United States (n = 133), (ii) longer term immigrants (n = 672), and (iii) U.S.-born individuals (n = 8,642). Logistic and Poisson regression, hierarchical generalized linear modeling, and survival analyses were conducted. Results: Late life immigrants were less likely to suffer from cancer, had lower numbers of chronic conditions at baseline, and displayed lower hazards of mortality during the 12-year follow-up. However, their self-rated health and functional status were worse than those of their counterparts over time. Conclusion: A HIE was only partially supported among older adults. © The Author(s) 2012.

Wang D.,Harvard University | Zhu W.,Harvard University | Best M.D.,University of Tennessee at Knoxville | Camden J.P.,University of Tennessee at Knoxville | Crozier K.B.,Harvard University
Nano Letters | Year: 2013

Controlling light from single emitters is an overarching theme of nano-optics. Antennas are routinely used to modify the angular emission patterns of radio wave sources. "Optical antennas" translate these principles to visible and infrared wavelengths and have been recently used to modify fluorescence from single quantum dots and single molecules. Understanding the properties of single molecules, however, would be advanced were one able to observe their vibrational spectra through Raman scattering in a very reproducible manner but it is a hugely challenging task, as Raman scattering cross sections are very weak. Here we measure for the first time the highly directional emission patterns of Raman scattering from single molecules in the feed gaps of optical antennas fabricated on a chip. More than a thousand single molecule events are observed, revealing that an unprecedented near-unity fraction of optical antennas have single molecule sensitivity. © 2013 American Chemical Society.

Asif I.M.,University of Tennessee at Knoxville | Drezner J.A.,University of Washington
Progress in Cardiovascular Diseases | Year: 2012

Sudden cardiac death (SCD) is the leading cause of death in young athletes during exercise, and there is international agreement among major medical and sporting bodies that young athletes should undergo preparticipation cardiovascular screening. However, there is currently no universally accepted screening protocol, and substantial debate exists about what constitutes the ideal approach to preparticipation screening. The primary objective of preparticipation screening is the detection of intrinsic structural or electrical cardiovascular disorders that predispose an athlete to SCD. Considerable evidence exists suggesting that screening athletes with only a history and physical examination leaves most athletes with a serious underlying cardiovascular disease undetected and, thus, cannot adequately achieve the primary objective of screening. Preparticipating cardiovascular screening inclusive of an electrocardiogram (ECG) greatly enhances the ability to identify athletes at risk and is the only model shown to be cost-effective and may reduce the rate of SCD. The major obstacle to ECG screening in the United States is the lack of a physician workforce skilled in interpretation of an athlete's ECG. However, recent studies have demonstrated a capacity to distinguish physiologic ECG alterations in athletes from findings suggestive of underlying pathology that is both feasible and has a low false-positive rate. Efforts are underway to increase physician education in ECG interpretation. After 2 decades debating the proper screening strategy to identify athletes at risk, the weight of scientific evidence suggests that a screening program inclusive of ECG is the only strategy that merits promotion. © 2012 Elsevier Inc..

Zhang Y.,University of Tennessee at Knoxville | Zhong Q.,University of Tennessee at Knoxville
Food Hydrocolloids | Year: 2013

Bixin, the major colorant component of annatto, is water insoluble and sensitive to degradation by temperature, pH, and light stresses. In this work, we studied an encapsulation process by spray drying warm 40% v/v aqueous ethanol solution with dissociated sodium caseinate (NaCas) and dissolved bixin. Upon hydration of spray-dried powder, transparent dispersions were observed at a wide pH range away from the isoelectric point (pI) of NaCas. The stability of bixin was much improved and the consistent yellow color was obtained. The volume-length mean particle diameters of capsules were around 250 nm in dispersions, slightly bigger than that of NaCas, based on dynamic light scattering, but the difference was not observed based on atomic force microscopy. Capsules and the mixture of NaCas and bixin showed different fluorescence and FTIR spectra. At pH near the pI of casein, soluble soybean polysaccharides adsorbed strongly onto capsules and stabilized them from aggregation. The simple encapsulation approach studied in the present work showed a promising process to enhance the stability and dispersibility of carotenoids using NaCas as a carrier, especially in transparent dispersions. © 2013 Elsevier Ltd.

Stromdahl E.Y.,U.S. Army | Hickling G.J.,University of Tennessee at Knoxville
Zoonoses and Public Health | Year: 2012

Since its emergence in the north-eastern and upper mid-western United States in the 1970s, Lyme disease, caused by Borrelia burgdorferi, has captured the public's attention as the nation's most prevalent vector-borne zoonotic disease. In contrast, recent publications on tick-pathogen systems in the eastern United States, and findings from Department of Defense investigations of ticks found biting military personnel, indicate that residents of the south-eastern United States are primarily at risk from emerging diseases caused by tick-borne pathogens other than B. burgdorferi. The risk of contracting these diseases varies greatly among states as a consequence of regional variation in the abundance of the key vector tick species. Moreover, this risk is changing, because tick distributions are in flux. To improve health outcomes, health providers need better information and awareness regarding which tick species bite humans in each state and which zoonotic pathogens are prevalent in these ticks. Effective diagnosis, treatment, control and reporting of tick-borne disease in the south-eastern United States require that health providers think 'beyond Lyme' and consider the marked regional differences in the tick species that bite humans and in the pathogens that these ticks carry. © 2012 Blackwell Verlag GmbH.

Qiao Z.-A.,Oak Ridge National Laboratory | Guo B.,Oak Ridge National Laboratory | Binder A.J.,University of Tennessee at Knoxville | Chen J.,Oak Ridge National Laboratory | And 3 more authors.
Nano Letters | Year: 2013

We have established a facile and generalizable "silica-assisted" synthesis for diverse carbon spheres - a category that covers mesoporous carbon nanospheres, hollow mesoporous carbon nanospheres, and yolk-shell mesoporous carbon nanospheres - by using phenolic resols as a polymer precursor, silicate oligomers as an inorganic precursor, and hexadecyl trimethylammoniumchloride as a template. The particle sizes of the carbon nanospheres are uniform and easily controlled in a wide range of 180-850 nm by simply varying the ethanol concentrations. All three types of mesoporous carbon nanospheres have high surface areas and large pore volumes and exhibit promising properties for supercapacitors with high capacitance and favorable capacitance retention. © 2012 American Chemical Society.

Rett B.S.,University of Tennessee at Knoxville | Whelan J.,University of Tennessee at Knoxville
Nutrition and Metabolism | Year: 2011

Background: Linoleic acid, with a DRI of 12-17 g/d, is the most highly consumed polyunsaturated fatty acid in the Western diet and is found in virtually all commonly consumed foods. The concern with dietary linoleic acid, being the metabolic precursor of arachidonic acid, is its consumption may enrich tissues with arachidonic acid and contribute to chronic and overproduction of bioactive eicosanoids. However, no systematic review of human trials regarding linoleic acid consumption and subsequent changes in tissue levels of arachidonic acid has been undertaken. Objective. In this study, we reviewed the human literature that reported changes in dietary linoleic acid and its subsequent impact on changing tissue arachidonic acid in erythrocytes and plasma/serum phospholipids. Design. We identified, reviewed, and evaluated all peer-reviewed published literature presenting data outlining changes in dietary linoleic acid in adult human clinical trials that reported changes in phospholipid fatty acid composition (specifically arachidonic acid) in plasma/serum and erythrocytes within the parameters of our inclusion/exclusion criteria. Results: Decreasing dietary linoleic acid by up to 90% was not significantly correlated with changes in arachidonic acid levels in the phospholipid pool of plasma/serum (p = 0.39). Similarly, when dietary linoleic acid levels were increased up to six fold, no significant correlations with arachidonic acid levels were observed (p = 0.72). However, there was a positive relationship between dietary gamma-linolenic acid and dietary arachidonic acid on changes in arachidonic levels in plasma/serum phospholipids. Conclusions: Our results do not support the concept that modifying current intakes of dietary linoleic acid has an effect on changing levels of arachidonic acid in plasma/serum or erythrocytes in adults consuming Western-type diets. © 2011 Rett and Whelan; licensee BioMed Central Ltd.

Ma X.,University of Tennessee at Knoxville | Djouadi S.M.,University of Tennessee at Knoxville | Li H.,University of Tennessee at Knoxville
IEEE Transactions on Wireless Communications | Year: 2012

Cognitive radio is a very popular research area in the communication community as cost and bandwidth can be saved by sensing the available licensed spectrum for unlicensed users. This paves the way for the application of cognitive radio in control systems over wireless communication links. A typical control system comprises a sensor interconnected with an actuator, a plant and controller. In this paper, it is assumed that the sensor and estimator communicate through a cognitive radio link. The state estimator needs to adjust to this new communication media as it is affected by interruptions from primary users, resulting in packet losses. The cognitive radio link is modeled as multiple semi-Markov processes each of which can capture the channel dynamics. Two different cases are considered. The first case assumes that acknowledgement of packet arrivals is available at the estimator while the second case does not. For the first case, sufficient conditions are derived for the stability of the peak covariance process which guarantees the stability of the estimator covariance. For the second case, an estimator is designed. Numerical examples are given to show the performance of the proposed estimators. Several applications of the proposed work are also discussed. © 2012 IEEE.

Lanzas C.,University of Tennessee at Knoxville | Dubberke E.R.,University of Washington
Infection Control and Hospital Epidemiology | Year: 2014

Objective. Both asymptomatic and symptomatic Clostridium difficile carriers contribute to new colonizations and infections within a hospital, but current control strategies focus only on preventing transmission from symptomatic carriers. Our objective was to evaluate the potential effectiveness of methods targeting asymptomatic carriers to control C. difficile colonization and infection (CDI) rates in a hospital ward: screening patients at admission to detect asymptomatic C. difficile carriers and placing positive patients into contact precautions. Methods. We developed an agent-based transmission model for C. difficile that incorporates screening and contact precautions for asymptomatic carriers in a hospital ward. We simulated scenarios that vary according to screening test characteristics, colonization prevalence, and type of strain present at admission. Results. In our baseline scenario, on average, 42% of CDI cases were community-onset cases. Within the hospital-onset (HO) cases, approximately half were patients admitted as asymptomatic carriers who became symptomatic in the ward. On average, testing for asymptomatic carriers reduced the number of new colonizations and HO-CDI cases by 40%-50% and 10%-25%, respectively, compared with the baseline scenario. Test sensitivity, turnaround time, colonization prevalence at admission, and strain type had significant effects on testing efficacy. Conclusions. Testing for asymptomatic carriers at admission may reduce both the number of new colonizations and HO-CDI cases. Additional reductions could be achieved by preventing disease in patients who are admitted as asymptomatic carriers and developed CDI during the hospital stay. © 2014 by The Society for Healthcare Epidemiology of America. All rights reserved.

Simberloff D.,University of Tennessee at Knoxville
PLoS Biology | Year: 2014

The earliest concept of a balance of nature in Western thought saw it as being provided by gods but requiring human aid or encouragement for its maintenance. With the rise of Greek natural philosophy, emphasis shifted to traits gods endowed species with at the outset, rather than human actions, as key to maintaining the balance. The dominance of a constantly intervening God in the Middle Ages lessened interest in the inherent features of nature that would contribute to balance, but the Reformation led to renewed focus on such features, particularly traits of species that would maintain all of them but permit none to dominate nature. Darwin conceived of nature in balance, and his emphasis on competition and frequent tales of felicitous species interactions supported the idea of a balance of nature. But Darwin radically changed its underlying basis, from God to natural selection. Wallace was perhaps the first to challenge the very notion of a balance of nature as an undefined entity whose accuracy could not be tested. His skepticism was taken up again in the 20th century, culminating in a widespread rejection of the idea of a balance of nature by academic ecologists, who focus rather on a dynamic, often chaotic nature buffeted by constant disturbances. The balance-of-nature metaphor, however, lives on in large segments of the public, representing a fragile aspect of nature and biodiversity that it is our duty to protect. © 2014 Daniel Simberloff.

Pighetti G.M.,University of Tennessee at Knoxville | Elliott A.A.,University of Missouri
Journal of Mammary Gland Biology and Neoplasia | Year: 2011

One of the most frequent mammary diseases impacting lactating animals is mastitis, an inflammation of the mammary gland most commonly caused by bacterial infection. The severity of mastitis is greatly influenced by the invading organism and the subsequent immune response which must recognize the foreign organism, recruit immune cells, eliminate the invading pathogen, and resolve the inflammatory response. The speed, strength, and duration of this response and subsequent disease susceptibility are critically tied to the genetic background of an animal. However, the genetic contribution has been difficult to identify due to the complex interactions that must occur for effective disease resistance. Recent studies have utilized polymorphisms to better define the genes and chromosomal regions that contribute to mastitis resistance. This review will examine these studies with primary emphasis in bovine systems, as the most work regarding mastitis has been conducted in this species. © Springer Science+Business Media, LLC 2011.

Hoban S.,University of Tennessee at Knoxville
Molecular Ecology | Year: 2014

Stochastic simulation software that simultaneously model genetic, population and environmental processes can inform many topics in molecular ecology. These include forecasting species and community response to environmental change, inferring dispersal ecology, revealing cryptic mating, quantifying past population dynamics, assessing in situ management options and monitoring neutral and adaptive biodiversity change. Advances in population demographic-genetic simulation software, especially with respect to individual life history, landscapes and genetic processes, are transforming and expanding the ways that molecular data can be used. The aim of this review is to explain the roles that such software can play in molecular ecology studies (whether as a principal component or a supporting function) so that researchers can decide whether, when and precisely how simulations can be incorporated into their work. First, I use seven case studies to demonstrate how simulations are employed, their specific advantage/necessity and what alternative or complementary (nonsimulation) approaches are available. I also explain how simulations can be integrated with existing spatial, environmental, historical and genetic data sets. I next describe simulation features that may be of interest to molecular ecologists, such as spatial and behavioural considerations and species' interactions, to provide guidance on how particular simulation capabilities can serve particular needs. Lastly, I discuss the prospect of simulation software in emerging challenges (climate change, biodiversity monitoring, population exploitation) and opportunities (genomics, ancient DNA), in order to emphasize that the scope of simulation-based work is expanding. I also suggest practical considerations, priorities and elements of best practice. This should accelerate the uptake of simulation approaches and firmly embed them as a versatile tool in the molecular ecologist's toolbox. © 2014 John Wiley & Sons Ltd.

Mannella N.,University of Tennessee at Knoxville
Journal of Physics Condensed Matter | Year: 2014

The determination of the most appropriate starting point for the theoretical description of Fe-based materials hosting high-temperature superconductivity remains among the most important unsolved problem in this relatively new field. Most of the work to date has focused on the pnictides, with LaFeAsO, BaFe2As2 and LiFeAs being representative parent compounds of three families known as 1111, 122 and 111, respectively. This topical review examines recent progress in this area, with particular emphasis on the implication of experimental data which have provided evidence for the presence of electron itinerancy and the detection of local spin moments. In light of the results presented, the necessity of a theoretical framework contemplating the presence and the interplay between itinerant electrons and large spin moments is discussed. It is argued that the physics at the heart of the macroscopic properties of pnictides Fe-based high-temperature superconductors appears to be far more complex and interesting than initially predicted. © 2014 IOP Publishing Ltd.

Pruitt J.N.,University of Tennessee at Knoxville
Functional Ecology | Year: 2010

Many animals are adapted for a 'feast or famine' existence, and will opportunistically engage in gluttonous foraging bouts. However, how gluttonous feeding influences individual performance (e.g. running speed) and the fitness consequence of modified performance are not frequently considered. Using laboratory track trials I establish baseline locomotor performances (burst speed) for four spider species: two active foragers (Hogna helluo and Schizocosa ocreata (family: Lycosidae)), and two sit-and-wait foragers (Agelenopsis emertoni and Barronopsis texana (family: Agelenidae)). I then fed each species ad libitum, assessed what influence this meal had on individuals' burst speed relative to baseline performance, and performed a field census to assess selection on running speed for all four species. Sit-and-wait foragers fed significantly more than active foragers and slowed significantly after feeding; however, neither active forager was slowed by their meal. My field census detected no selection on speed for sit-and-wait foragers, and positive directional selection on speed for both active foragers. The negative association between the amount of food consumed and selection on burst speed suggests that selection pressures to maintain locomotor performance may set an upper limit to how much an animal can, or will, eat during a foraging bout. © 2009 The Author. Journal compilation © 2009 British Ecological Society.

Wilkins J.F.,Santa Fe Institute | Ubeda F.,University of Tennessee at Knoxville
Progress in Molecular Biology and Translational Science | Year: 2011

Genomic imprinting is the phenomenon where the expression of a locus differs between the maternally and paternally inherited alleles. Typically, this manifests as transcriptional silencing of one of the alleles, although many genes are imprinted in a tissue- or isoform-specific manner. Diseases associated with imprinted genes include various cancers, disorders of growth and metabolism, and disorders in neurodevelopment, cognition, and behavior, including certain major psychiatric disorders. In many cases, the disease phenotypes associated with dysfunction at particular imprinted loci can be understood in terms of the evolutionary processes responsible for the origin of imprinting. Imprinted gene expression represents the outcome of an intragenomic evolutionary conflict, where natural selection favors different expression strategies for maternally and paternally inherited alleles. This conflict is reasonably well understood in the context of the early growth effects of imprinted genes, where paternally inherited alleles are selected to place a greater demand on maternal resources than are maternally inherited alleles. Less well understood are the origins of imprinted gene expression in the brain, and their effects on cognition and behavior. This chapter reviews the genetic diseases that are associated with imprinted genes, framed in terms of the evolutionary pressures acting on gene expression at those loci. We begin by reviewing the phenomenon and evolutionary origins of genomic imprinting. We then discuss diseases that are associated with genetic or epigenetic defects at particular imprinted loci, many of which are associated with abnormalities in growth and/or feeding behaviors that can be understood in terms of the asymmetric pressures of natural selection on maternally and paternally inherited alleles. We next described the evidence for imprinted gene effects on adult cognition and behavior, and the possible role of imprinted genes in the etiology of certain major psychiatric disorders. Finally, we conclude with a discussion of how imprinting, and the evolutionarygenetic conflicts that underlie it, may enhance both the frequency and morbidity of certain types of diseases. © 2011 Elsevier Inc.

Rice W.R.,University of California at Santa Barbara | Friberg U.,Uppsala University | Gavrilets S.,University of Tennessee at Knoxville
BioEssays | Year: 2013

We recently synthesized and reinterpreted published studies to advance an epigenetic model for the development of homosexuality (HS). The model is based on epigenetic marks laid down in response to the XX vs. XY karyotype in embryonic stem cells. These marks boost sensitivity to testosterone in XY fetuses and lower it in XX fetuses, thereby canalizing sexual development. Our model predicts that a subset of these canalizing epigenetic marks stochastically carry over across generations and lead to mosaicism for sexual development in opposite-sex offspring - the homosexual phenotype being one such outcome. Here, we begin by outlining why HS has been under-appreciated as a commonplace phenomenon in nature, and how this trend is currently being reversed in the field of neurobiology. We next briefly describe our epigenetic model of HS, develop a set of predictions, and describe how epigenetic profiles of human stem cells can provide for a strong test of the model. © 2013 The Authors. Bioessays published by WILEY Periodicals, Inc.

Li H.,University of Tennessee at Knoxville
IEEE International Symposium on Information Theory - Proceedings | Year: 2015

In order to understand how to operate the physical dynamics of cyber physical systems (CPSs), we study the control of entropy (or equivalently uncertainty) via communications in CPSs. We consider the controller as the Maxwell's demon that decimates the system entropy. Due to the second law of thermodynamics, the system entropy cannot be spontaneously decreased. Therefore, to reduce the system entropy, the controller needs external information communicated from sensors. For a finite state physical system in CPS, we derive upper and lower bounds for the communication requirements. The optimal designs of message mechanism and control policy are proposed. © 2015 IEEE.

Zhang F.,University of Washington | Holleman J.,University of Tennessee at Knoxville | Otis B.P.,University of Washington
IEEE Transactions on Biomedical Circuits and Systems | Year: 2012

Rapid development in miniature implantable electronics are expediting advances in neuroscience by allowing observation and control of neural activities. The first stage of an implantable biosignal recording system, a low-noise biopotential amplifier (BPA), is critical to the overall power and noise performance of the system. In order to integrate a large number of front-end amplifiers in multichannel implantable systems, the power consumption of each amplifier must be minimized. This paper introduces a closed-loop complementary-input amplifier, which has a bandwidth of 0.05 Hz to 10.5 kHz, an input-referred noise of 2.2 μ V rms , and a power dissipation of 12 μ W. As a point of comparison, a standard telescopic-cascode closed-loop amplifier with a 0.4 Hz to 8.5 kHz bandwidth, input-referred noise of 3.2 μ V rms , and power dissipation of 12.5 μ W is presented. Also for comparison, we show results from an open-loop complementary-input amplifier that exhibits an input-referred noise of 3.6 μ V rms while consuming 800 nW of power. The two closed-loop amplifiers are fabricated in a 0.13 μ m CMOS process. The open-loop amplifier is fabricated in a 0.5 μ m SOI-BiCMOS process. All three amplifiers operate with a 1 V supply. © 2007-2012 IEEE.

Graham K.L.,Texas State University | Burghardt G.M.,University of Tennessee at Knoxville
Quarterly Review of Biology | Year: 2010

There has been a recent resurgence of interest in the study of play behavior, marked by much empirical research and theoretical review. These efforts suggest that play may be of greater biological significance than most scientists realize. Here we present a brief synopsis of current play research covering issues of adaptive function, phylogeny, causal mechanisms, and development. Our goal is to selectively highlight contemporary areas of research in which the underlying processes and consequences of play should not be ignored. We elucidate some of the new and burgeoning areas of play research and interpret them from an integrative biological theoretical perspective that highlights areas in need of further experimental, comparative, and field research. Copyright © 2010 by The University of Chicago. All rights reserved.

Pruitt J.N.,University of Tennessee at Knoxville | Krauel J.J.,University of Tennessee at Knoxville
Journal of Evolutionary Biology | Year: 2010

Animals vary greatly in their tendency to consume large meals. Yet, whether or how meal size influences fitness in wild populations is infrequently considered. Using a predator exclusion, mark-recapture experiment, we estimated selection on the amount of food accepted during an ad libitum feeding bout (hereafter termed 'satiation threshold') in the wolf spider Schizocosa ocreata. Individually marked, size-matched females of known satiation threshold were assigned to predator exclusion and predator inclusion treatments and tracked for a 40-day period. We also estimated the narrow-sense heritability of satiation threshold using dam-on-female-offspring regression. In the absence of predation, high satiation threshold was positively associated with larger and faster egg case production. However, these selective advantages were lost when predators were present. We estimated the heritability of satiation threshold to be 0.56. Taken together, our results suggest that satiation threshold can respond to selection and begets a life history trade-off in this system: high satiation threshold individuals tend to produce larger egg cases but also suffer increased susceptibility to predation. © 2010 European Society For Evolutionary Biology.

MacLennan B.J.,University of Tennessee at Knoxville
International Journal of General Systems | Year: 2014

Future computing paradigms and technologies will have to be more like the physical processes by which they are realized, and because these processes are primarily continuous, post-Moore's law computing will involve an increased use of analog computation. Traditionally analog computers have computed ordinary differential equations of time, but analog field computation permits massively parallel temporal integration of partial differential equations. In principle many different physical media - not just electronics - can be exploited to implement the basic operations of analog computing, a small number of which are sufficient to approximate a wide variety of analog computations, thus providing a basis for universal analog computation and general-purpose analog computers. The contentious issue of the computational power of analog computers is addressed best on its own terms, rather by asking it within the context of Church-Turing computation, which distorts the relevant questions and their answers. © 2014 Taylor & Francis.

McCain C.M.,University of Colorado at Boulder | Sanders N.J.,University of Tennessee at Knoxville
Ecology | Year: 2010

The Metabolic Theory of Ecology (MTE) posits that the temperature-dependent kinetics of metabolism shape broad-scale patterns of biodiversity. Here we test whether the MTE accounts for patterns of diversity using 102 elevational diversity gradients of reptiles and amphibians. In particular, we examined the support for the two key predictions of the MTE: that the reciprocal of absolute temperature (1/kT) and diversity are linearly related and that the slope of that relationship is -0.65. We also tested two underlying assumptions of the MTE in cases with appropriate data, namely, that abundance is invariant among samples, and that behavioral thermoregulation influences the MTE predictions. We found that few studies supported the predictions of the MTE for the relationship between environmental temperature and elevational diversity using previous methods on individual gradients and using metaanalysis. The predominant relationship was curvilinear, and the slopes were steeper than predicted. In analyses of individual gradients, only 6% followed the MTE predictions in the strictest application, and 25% in the broadest. We found violations of the assumption of invariant abundances in all five test cases. All four herpetofaunal groups, regardless of behavioral thermoregulatory abilities, demonstrated poor fits to the MTE predictions. Even when arid gradients are removed, ameliorating the potential effects of water limitation, the MTE did not account for herpetofaunal elevational diversity. We conclude that an interplay of factors shapes elevational diversity gradients rather than the simple kinetics of biochemical reactions. © 2010 by the Ecological Society of America.

Chakraborty S.,University of Tennessee at Knoxville
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

This paper extends the framework for merging sociologically inspired rational cognitive models of decision making with social media inspired feedback mechanisms. This model, with certain simplifying assumptions, is used to analyze the effects of external influence on the dynamics of opinion evolution in a fully connected society. The master equation is shown to have the form of the Fokker-Planck equation, and the necessary and sufficient conditions for a polynomial solution are investigated. It is proved that the parameters of the model guarantees the existence of a polynomial solution. © 2013 Springer-Verlag.

Winter S.E.,University of Tennessee at Knoxville | Barber J.P.,Adelphi University
Patient Preference and Adherence | Year: 2013

Patient treatment preferences are of growing interest to researchers, clinicians, and patients. In this review, an overview of the most commonly recommended treatments for depression is provided, along with a brief review of the evidence supporting their efficacy. Studies examining the effect of patient treatment preferences on treatment course and outcome are summarized. Existing literature on what treatment options patients tend to prefer and believe to be helpful, and what factors may affect these preferences, is also reviewed. Finally, clinical implications of research findings on patient preferences for depression management are discussed. In summary, although our knowledge of the impact of patient preferences on treatment course and outcome is limited, knowing and considering those preferences may be clinically important and worthy of greater study for evidence-based practice. © 2013 Winter and Barber.

Davies A.G.,Jet Propulsion Laboratory | Ennis M.E.,University of Tennessee at Knoxville
Icarus | Year: 2011

Zamama, Culann, and Tupan Patera are three large, persistent volcanic centers on the jovian moon Io. As part of an ongoing project to quantify contributions from individual volcanic centers to Io's thermal budget, we have quantified the radiant flux from all suitable observations made by the Galileo Near Infrared Mapping Spectrometer (NIMS) of these volcanoes, in some cases filling omissions in previous analyses. At Zamama, after a long period of cooling, we see a peak in thermal emission that corresponds with new plume activity. Subsequently, toward the end of the Galileo epoch, thermal emission from Zamama drops off in a manner consistent with a greatly reduced eruption rate and the cooling of emplaced flows. Culann exhibits possible episodic activity. We present the full Tupan Patera NIMS dataset and derive new estimates of thermal output and temporal behavior. Eruption rates at these three volcanoes are on the order of 30m3s-1, consistent with a previous analysis of NIMS observations of Prometheus, and nearly an order of magnitude greater than Kilauea volcano, Hawai'i, Earth's most active volcano. We propose that future missions to the jovian system could better constrain activity at these volcanoes and others where similar styles of activity are taking place by obtaining data on a time scale of, ideally, at least one observation per day. Observations at similar or even shorter timescales are desirable during initial waxing phases of eruption episodes. These eruptions are identifiable from their characteristic spectral signatures and temporal behavior. © 2011 Elsevier Inc.

Mollenkopf D.A.,University of Tennessee at Knoxville | Frankel R.,University of North Florida | Russo I.,University of Verona
Journal of Operations Management | Year: 2011

Managing the return flow of product is increasingly recognized as a strategically important activity that involves decisions and actions within and across firms. We focus specifically on returns management at the marketing-operations interface, by utilizing the conceptualization of customer value and its related drivers. In order to explore the phenomenon of returns management across a multi-disciplinary, managerial spectrum, a qualitative research methodology relying on individual managers' perceptions was chosen to generate depth of understanding given the limited current understanding of the research topic under consideration. Our results suggest that functional integration at the marketing-operations interface can lead to better alignment of corporate resources and thus create higher levels of customer value. We also found the external business environment to impact how and why a firm creates customer value through the returns management process. Overall, our results suggest that when returns management is recognized as a matter of a firm's competitiveness, the joint role of operations and marketing is imperative to success. © 2010 Elsevier B.V. All rights reserved.

Kravitz J.N.,University of Tennessee at Knoxville | Berry M.W.,Medical University of South Carolina | Schabel S.I.,Medical University of South Carolina | Judson M.A.,Albany Medical College
Chest | Year: 2013

Background: Pulmonary aspergillomas may cause life-threatening hemoptysis. The treatment of this condition is problematic because poor pulmonary function often precludes definitive surgical resection. Methods: We retrospectively reviewed all patients hospitalized at our institution for hemoptysis associated with an aspergilloma over an 8-year period and who underwent percutaneous intracavitary instillation of amphotericin B (ICAB). ICAB consisted of catheter placement into the aspergilloma cavity with subsequent instillation of 50 mg amphotericin B in 20 mL 5% dextrose solution daily for 10 days. Results: ICAB was attempted for 23 distinct episodes of severe hemoptysis in 20 individual patients. Catheter placement was successful in 21 of the 23 episodes (91%), and of these, ICAB instillation was successfully completed in 20 episodes (95%). In these 20 episodes, hemoptysis ceased by hospital discharge in 17 of 20 patients (85%) and in all 18 who survived until a follow-up visit 1-month after treatment. Pneumothorax occurred in six of 23 (26%) catheter placement attempts without long-term complications. Recurrence of serious hemoptysis occurred after six of 18 episodes for which follow-up was available. Potential risk factors associated with severe, recurrent hemoptysis were a size increase or reappearance of the aspergilloma on a chest CT scan (P = .001), bleeding diathesis (P = .08), and lack of bronchial artery embolization during index hospitalization (P = .07). Conclusions: Our data suggest that ICAB is an effective short-term treatment to control severe hemoptysis caused by pulmonary aspergilloma. The long-term benefit of this procedure is unknown. We identified several potential risk factors for recurrent hemoptysis after ICAB that could be examined prospectively in future trials. © 2013 American College of Chest Physicians.

Emery J.P.,University of Tennessee at Knoxville | Burr D.M.,University of Tennessee at Knoxville | Cruikshank D.P.,NASA
Astronomical Journal | Year: 2011

The Trojan asteroids, a very substantial population of primitive bodies trapped in Jupiter's stable Lagrange regions, remain quite poorly understood. Because they occupy these orbits, the physical properties of Trojans provide a unique perspective on the chemical and dynamical processes that shaped the Solar System. The current study was therefore undertaken to investigate surface compositions of these objects. We present 66 new near-infrared (NIR; 0.7-2.5 μm) spectra of 58 Trojan asteroids, including members of both the leading and trailing swarms. We also include in the analysis previously published NIR spectra of 13 Trojans (3 of which overlap with the new sample). This data set permits not only a direct search for compositional signatures, but also a search for patterns that may reveal clues to the origin of the Trojans. We do not report any confirmed absorption features in the new spectra. Analysis of the spectral slopes, however, reveals an interesting bimodality among the NIR data. The two spectral groups identified appear to be equally abundant in the leading and trailing swarms. The spectral groups are not a result of family membership; they occur in the background, non-family population. The average albedos of the two groups are the same within uncertainties (0.051 ±0.016 and 0.055 ±0.016). No correlations between spectral slope and any other physical or orbital parameter are detected, with the exception of a possible weak correlation with inclination among the less-red spectral group. The NIR spectral groups are consistent with a similar bimodality previously suggested among visible colors and spectra. Synthesizing the present results with previously published properties of Trojans, we conclude that the two spectral groups represent objects with different intrinsic compositions. We further suggest that whereas the less-red group originated near Jupiter or in the main asteroid belt, the redder spectral group originated farther out in the Solar System. If this suggestion is correct, the Trojan swarms offer the most readily accessible large reservoir of Kuiper Belt material as well as a unique reservoir for the study of material from the middle part of the solar nebula. © 2011 The American Astronomical Society. All rights reserved.

Zenni R.D.,University of Tennessee at Knoxville | Simberloff D.,University of Tennessee at Knoxville
Biological Invasions | Year: 2013

To understand current patterns of Pinus invasion in an Araucaria forest in southern Brazil, we quantified invasion at the local scale and compared it with habitat characteristics, propagule size, and number of source populations, using generalized linear models. We also compared observed and expected invasive species status based on a previously developed model (Z scores) using Chi square and correlation tests to evaluate the predictability of species status based on their traits. Of the 16 Pinus species currently present in the site, three are invasive (P. elliottii, P. glabra, and P. taeda), three are naturalized (P. clausa, P. oocarpa, and P. pseudostrobus), and ten are present only as the originally planted individuals. While P. taeda spread the farthest, P. glabra had greater overall density, but none of the invasive species has spread more than 250 m in 45 years. Invasive Pinus plants were found where forest tree density was below 805 trees ha-1, and invasive Pinus density decreased log-linearly with an increase in native tree density. Number of individuals introduced and number of source populations were strong predictors of naturalization, thus both propagule size and propagule diversity can potentially be driving invasion success. Z scores based on species traits did not predict which species would invade in Rio Negro. Our findings suggest that Araucaria forests might not resist invasion by Pinus as recently suggested and support the hypothesis that propagule pressure is a fundamental driver of invasions with propagule diversity being a possible component of this mechanism. © 2012 Springer Science+Business Media Dordrecht.

Juslin N.,University of Tennessee at Knoxville | Wirth B.D.,University of Tennessee at Knoxville
Journal of Nuclear Materials | Year: 2013

A new interatomic pair potential for W-He is described, which includes a short range modification to the Ackland-Thetford tungsten potential. Molecular dynamics simulations using these potentials accurately reproduce ab initio results of the formation energies and ground state positions of He point defects and self interstitial atoms in W. Simulations of larger He-vacancy clusters with up to 20 vacancies and 120 He atoms show strong binding of both He and vacancies to He-vacancy clusters for all cluster sizes. For small clusters, the qualitative agreement with ab initio results is good, although the vacancy binding energy is overestimated by the interatomic potential. © 2012 Elsevier B.V. All rights reserved.

Keppens V.,University of Tennessee at Knoxville
Nature Materials | Year: 2013

Ferroelectric materials exhibit an intrinsic electric polarization that can be changed or reversed by an applied electric field. While initially ferroelectrics were little more than an academic curiosity, today they can be found at the heart of many technological devices that exploit their ferro-, piezo- and pyroelectric properties, with the most advanced application perhaps being that of ferroelectric non-volatile memories. The structure of the low-temperature ferroelectric material is always non-centrosymmetric, and therefore does not display inversion symmetry, as this prevents the charge separation inherent to the electric polarization. The compound BaTiO3 is often regarded as the prototypical ferroelectric, belonging to a family of ferroelectrics known as perovskite oxides. The low-temperature ferroelectric phase is obtained from small symmetry-breaking displacements of the Li atoms, with the loss of the inversion symmetry resulting in a spontaneous polarization at 1,483 K.

Gali A.,Oak Ridge National Laboratory | Gali A.,University of Tennessee at Knoxville | George E.P.,Oak Ridge National Laboratory | George E.P.,University of Tennessee at Knoxville
Intermetallics | Year: 2013

Equiatomic, face-centered-cubic, high- and medium-entropy alloys were arc melted, hot-rolled to produce recrystallized sheets, and tensile tested. The alloys having the compositions CrMnFeCoNi and CrFeCoNi exhibited a strong temperature-dependent decrease in strength with increasing temperature from -196 °C to 1000 °C, and a relatively weak strain-rate dependence (at 10 -3 and 10-1 s-1). Ductility did not vary inversely with yield strength; rather, when strength doubled as the test temperature was decreased from room temperature to -196 °C, elongation to fracture increased by a factor of 1.5 to >60%. A high degree of work hardening, possibly due to deformation-induced nanotwinning, postpones the onset of necking and may be the reason for the ductility increase. © 2013 Elsevier Ltd. All rights reserved.

Collins C.,University of Tennessee at Knoxville | Shen J.,Purdue University | Wise S.M.,University of Tennessee at Knoxville
Communications in Computational Physics | Year: 2013

We present an unconditionally energy stable and uniquely solvable finite difference scheme for the Cahn-Hilliard-Brinkman (CHB) system, which is comprised of a Cahn-Hilliard-type diffusion equation and a generalized Brinkman equation modeling fluid flow. The CHB system is a generalization of the Cahn-Hilliard-Stokes model and describes two phase very viscous flows in porous media. The scheme is based on a convex splitting of the discrete CH energy and is semi-implicit. The equations at the implicit time level are nonlinear, but we prove that they represent the gradient of a strictly convex functional and are therefore uniquely solvable, regardless of time step size. Owing to energy stability, we show that the scheme is stable in the time and space discrete l ∞(0,T;H h 1) and l 2(0,T;H h 2) norms. We also present an efficient, practical nonlinear multigrid method - comprised of a standard FAS method for the Cahn-Hilliard part, and a method based on the Vanka smoothing strategy for the Brinkman part - for solving these equations. In particular, we provide evidence that the solver has nearly optimal complexity in typical situations. The solver is applied to simulate spinodal decomposition of a viscous fluid in a porous medium, as well as to the more general problems of buoyancy- and boundary-driven flows. © 2013 Global-Science Press.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2014

The mass transport properties of a non-retained (thiourea) and three retained low molecular weight compounds (acetophenone, valerophenone, and octanophenone) along a 4.6mm×45mm PROSWIFT™ RP-1S monolithic column made of rigid cross-linked poly(styrene-divinylbenzene) copolymer was investigated in depth. Accurate protocols (peak parking experiments, measurement of the first and second central moments of peak profiles by numerical integration) combined with the use of validated models of effective diffusion along monolithic structures were applied for the determination of the longitudinal diffusion, the eddy dispersion, and the skeleton-eluent mass transfer resistances due to the finite analyte diffusivity across the polymer skeleton and to the slow absorption kinetics into the polymer volume. Experimental results show by increasing order of importance evidence that the resolution performance of this short and wide polymer-based monolithic HPLC column is limited by the slow analyte diffusivity across the polymer skeleton (smaller than one tenth of the bulk diffusion coefficient for k'>1), its large eddy dispersion HETP (Heddy≃100μm), and the slow rate of absorption (≃10Hz only) in the polymer volume for retained analytes. The column performance could be improved by preparing a more homogeneous material with a rigid internal mesoporous structure. This would provide a column bed having a larger specific surface area, allowing faster analyte diffusion across the mesoporous skeleton, a smaller eddy dispersion HETP, and a faster absorption kinetics in the polymeric monolith than those observed for the currently available materials. © 2014 Elsevier B.V.

Khairoutdinov M.F.,State University of New York at Stony Brook | Yang C.-E.,University of Tennessee at Knoxville
Atmospheric Chemistry and Physics | Year: 2013

The study attempts to evaluate the aerosol indirect effects over tropical oceans in regions of deep convection applying a three-dimensional cloud-resolving model run over a doubly-periodic domain. The Tropics are modelled using a radiative-convective equilibrium idealisation when the radiation, turbulence, cloud microphysics and surface fluxes are explicitly represented while the effects of large-scale circulation are ignored. The aerosol effects are modelled by varying the number concentration of cloud condensation nuclei (CCN) at 1% supersaturation, which serves as a proxy for the aerosol amount in the environment, over a wide range, from pristine maritime (50 cm-3) to polluted (1000 cm-3) conditions. No direct effects of aerosol on radiation are included. Two sets of simulations have been run: fixed (noninteractive) sea surface temperature (SST) and interactive SST as predicted by a simple slab-ocean model responding to the surface radiative fluxes and surface enthalpy flux. Both sets of experiments agree on the tendency of increased aerosol concentrations to make the shortwave cloud forcing more negative and reduce the longwave cloud forcing in response to increasing CCN concentration. These, in turn, tend to cool the SST in interactive-SST case. It is interesting that the absolute change of the SST and most other bulk quantities depends only on relative change of CCN concentration; that is, same SST change can be the result of doubling CCN concentration regardless of clean or polluted conditions. It is found that the 10-fold increase of CCN concentration can cool the SST by as much as 1.5 K. This is quite comparable to 2.1-2.3K SST warming obtained in a simulation for clean maritime conditions, but doubled CO2 concentration. Assuming the aerosol concentration has increased from preindustrial time by 30 %, the radiative forcing due to indirect aerosol effects is estimated to be -0.3Wm-2. It is found that the indirect aerosol effect is dominated by the first (Twomey) effect. Qualitative differences between the interactive and fixed SST cases have been found in sensitivity of the hydrological cycle to the increase in CCN concentration; namely, the precipitation rate shows some tendency to increase in fixed SST case, but robust tendency to decrease in interactive SST case. © Author(s) 2013.

Wang C.,University of Tennessee at Knoxville | Paddison S.J.,University of Tennessee at Knoxville
Physical Chemistry Chemical Physics | Year: 2010

Ionomers with protogenic groups such as phosphonic acid have recently been proposed as suitable polymer electrolyte membranes for fuel cells operating with little humidification due to their extraordinary amphotericity. The hydrogen bonding and energetics associated with proton transfer of substituted phosphonic acid molecules and their self-condensation products (anhydride + H 2O) are examined through ab initio electronic structure calculations. The global minimum energy structures of methyl-, phenyl-, benzyl-, trifluoromethyl- and phenyldifluoro-phosphonic acids determined at the B3LYP/6-311G** level indicate that the fluorinated molecules exhibit slightly stronger binding to water than the non-fluorinated molecules. The potential energy profiles for transfer of a proton within the condensation products were obtained at the B3LYP/6-311G** level for each of the acids, and revealed that the trifluoromethyl system has the lowest endothermicity (5.3 kcal mol-1) in contrast to the methyl system which has the greatest endothermicity (7.1 kcal mol-1) and a barrier of 7.6 kcal mol-1. When no constraints are imposed on the system, proton transfer from the anhydride to a water molecule (primary) is accompanied by a secondary proton transfer (from protonated water molecule back to the anhydride) in all cases except the trifluoromethyl anhydride where charge separation and formation of a hydronium ion occurs. It appears that the secondary proton transfer would substantially determine the emergence of transition states and the correlated endothermicities. © 2010 the Owner Societies.

Type I toxin-antitoxin loci consist of two genes: one encodes a small, toxic protein and the second encodes a small RNA antitoxin that represses toxin gene expression. These pairs were first described on plasmids where they regulate plasmid maintenance. However, recent discoveries have found novel type I loci, with no homology to plasmid sequences, in the chromosome of Escherichia coli and closely related species. The Ibs-Sib, ShoB-OhsC and Zor-Orz loci are examples of these new loci. For these toxic proteins, much more is known about how their expression is regulated than their biological function. Although all are found in E. coli and closely related bacteria, there is great variation among species as to which loci they possess. Herein, I discuss how these sRNA antitoxins prevent toxin production and how the distribution of these loci across species may be providing insights into their true function. © 2012 Landes Bioscience.

Rhinehart J.L.,University of Tennessee at Knoxville | Mitchell N.E.,University of Tennessee at Knoxville | Long B.K.,University of Tennessee at Knoxville
ACS Catalysis | Year: 2014

Sterically demanding 2,6-bis(diphenylmethyl)-4-methylaniline was condensed onto acenaphthenequinone via an aminoalane intermediate and metalated using nickel(II) dibromide dimethoxyethane adduct to yield bis[(2,6-dibenzhydryl-4- methylimino) acenaphthene]dibromo nickel(II). This α-diimine precatalyst was examined for high-temperature ethylene polymerization and proved to be thermally robust at temperatures as high as 90 °C, demonstrating enhanced activity as compared with related catalysts. Furthermore, the resultant polymers displayed increased melting transitions as compared with those produced using catalysts with identical N-aryl moieties appended to nonacenaphthenequinone- derived ligand backbones. © 2014 American Chemical Society.

Liu N.,University of Tennessee at Knoxville | Liu N.,Anhui University of Science and Technology | Khomami B.,University of Tennessee at Knoxville
Physical Review Letters | Year: 2013

We report for the first time the polymer-induced breakdown of large-scale Taylor vortex structures leading to drag enhancement in viscoelastic turbulent Taylor-Couette flows. Specifically, we demonstrate that upon the addition of trace amounts of soluble high molecular weight macromolecules the Newtonian large-scale Taylor vortices are replaced by small-scale vortices in the inner and outer cylinder wall regions. This flow transition and a commensurate drag increase of up to 62% are facilitated by the presence of large polymeric normal stresses in a narrow region immediately close to the outer wall. A simple mechanism for this striking flow transition is proposed with the aim of paving the way for a mechanistic understanding of polymer-induced structure and drag modifications in high-Re turbulent curvilinear flows. © 2013 American Physical Society.

Boder E.T.,University of Tennessee at Knoxville | Jiang W.,University of Tennessee at Knoxville
Annual Review of Chemical and Biomolecular Engineering | Year: 2011

The advent of modern antibody engineering has led to numerous successes in the application of these proteins for cancer therapy in the 13 years since the first Food and Drug Administration approval, which has stimulated active interest in developing more and better drugs based on these molecules. A wide range of tools for discovering and engineering antibodies has been brought to bear on this challenge in the past two decades. Here, we summarize mechanisms of monoclonal antibody therapeutic activity, challenges to effective antibody-based treatment, existing technologies for antibody engineering, and current concepts for engineering new antibody formats and antibody alternatives as next generation biopharmaceuticals for cancer treatment. © Copyright 2011 by Annual Reviews. All rights reserved.

Ebadian M.A.,Florida International University | Lin C.X.,University of Tennessee at Knoxville
Journal of Heat Transfer | Year: 2011

In recent years, high-heat-flux cooling techniques have received great attention from researchers around the world due to its importance in thermal management of both commercial and defense high-power electronic devices. Although impressive progress has been made during the last few decades, high-heat-flux removal still largely remains as a challenging subject that needs further exploration and study. In this paper, we have reviewed recent developments in several high-heat-flux heat removal techniques, including microchannels, jet impingements, sprays, wettability effects, and piezoelectrically driven droplets. High-heat-flux removal can be achieved effectively by either single-phase flow or two-phase flow boiling heat transfer. Better understandings of the underlying heat transfer mechanisms for performance improvement are discussed. © 2011 American Society of Mechanical Engineers.

Iwashita T.,University of Tennessee at Knoxville | Egami T.,University of Tennessee at Knoxville | Egami T.,Oak Ridge National Laboratory
Physical Review Letters | Year: 2012

Atomic correlations in a simple liquid in steady-state flow under shear stress are studied by molecular dynamics simulation. The local atomic level strain is determined through the anisotropic pair-density function. The atomic level strain has a limited spatial extension whose range is dependent on the strain rate and extrapolates to zero at the critical strain rate. A failure event is identified with altering the local topology of atomic connectivity by exchanging bonds among neighboring atoms. © 2012 American Physical Society.

Binder B.M.,University of Tennessee at Knoxville | Rodriguez F.I.,University of Wisconsin - Madison | Bleecker A.B.,University of Wisconsin - Madison
Journal of Biological Chemistry | Year: 2010

Plants utilize ethylene as a hormone to regulate multiple developmental processes and to coordinate responses to biotic and abiotic stress. In Arabidopsis thaliana, a small family of five receptor proteins typified by ETR1 mediates ethylene perception. Our previous work suggested that copper ions likely play a role in ethylene binding. An independent study indicated that the ran1 mutants, which display ethylene-like responses to the ethylene antagonist trans-cyclooctene, have mutations in the RAN1 copper-transporting P-type ATPase, once again linking copper ions to the ethylene-response pathway. The results presented herein indicate that genetically engineered Saccharomyces cerevisiae expressing ETR1 but lacking the RAN1 homolog Ccc2p (Δccc2) lacks ethylene-binding activity. Ethylene-binding activity was restored when copper ions were added to the Δccc2 mutants, showing that it is the delivery of copper that is important. Additionally, transformation of the Δccc2 mutant yeast with RAN1 rescued ethylene-binding activity. Analysis of plants carrying loss-of-function mutations in ran1 showed that they lacked ethylene-binding activity, whereas seedlings carrying weak alleles of ran1 had normal ethylene-binding activity but were hypersensitive to copper-chelating agents. Altogether, the results show an essential role for RAN1 in the biogenesis of the ethylene receptors and copper homeostasis in Arabidopsis seedlings. Furthermore, the results indicate cross-talk between the ethylene-response pathway and copper homeostasis in Arabidopsis seedling development. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2012

The theory of gradient elution usually assumes a constant flow rate. This works extends it to gradients performed under constant pressure drop and variable flow rates. The peak capacity is derived under both constant flow rate and constant pressure gradient chromatography by integrating the rate of increase of the peak capacity from the hold-up time to the end of the gradient time. Assuming that the eluent mixture is incompressible, the chromatographic system isothermal, the pressure has no effect on the retention pattern, and neglecting the contributions of the instrument to the total pressure drop and the total peak width, it is found that both modes of gradient elution chromatography are strictly equivalent, provided that the elution time of the last eluted compound and the volume gradient are kept the same in both cases. © 2012 Elsevier B.V.

Pedigo A.S.,University of Tennessee at Knoxville | Odoi A.,University of Tennessee at Knoxville
Annals of Epidemiology | Year: 2010

Purpose: Stroke and myocardial infarction (MI) require timely geographic accessibility to emergency care. Historically, studies used straight line distances as measures of geographic accessibility. Recently, travel time has been recognized as a better indicator of accessibility because travel impedances can be considered. This study used finer grained transportation data and network analysis to investigate neighborhood disparities in travel time to emergency stroke and MI care. Methods: Travel times to stroke and cardiac centers were computed using network analysis, while considering distance, speed limit, road connectivity, and turn impedances. Neighborhoods within 30, 60, or 90 minutes travel were identified. Travel time by air ambulance was calculated and adjusted for flying speed and some delays. Results: Approximately 8% and 15% of the study population did not have timely geographic accessibility to emergency stroke and MI care, respectively. Populations with poor access were located in rural areas. The entire study population had timely access by air ambulance. Conclusions: This study identified disparities in geographic accessibility to emergency stroke and MI care in East Tennessee. Use of air ambulance or telemedicine could play a vital role in addressing these disparities. This information is important for evidence-based health planning and resource allocation. © 2010 Elsevier Inc.

Marchetti F.,Lawrence Berkeley National Laboratory | Venkatachalam S.,University of Tennessee at Knoxville
Cell Cycle | Year: 2010

Aneuploidy, any deviation from an exact multiple of the haploid number of chromosomes, is a common occurrence in cancer and represents the most frequent chromosomal disorder in newborns. Eukaryotes have evolved mechanisms to assure the fidelity of chromosome segregation during cell division that include a multiplicity of checks and controls. One of the main cell division control mechanisms is the spindle assembly checkpoint (SAC) that monitors the proper attachment of chromosomes to spindle fibers and prevents anaphase until all kinetochores are properly attached. The mammalian SAC is composed of at least 14 evolutionary-conserved proteins that work in a coordinated fashion to monitor the establishment of amphitelic attachment of all chromosomes before allowing cell division to occur. Among the SAC proteins, the budding uninhibited by benzimidazole protein 1 (Bub1), is a highly conserved protein of prominent importance for the proper functioning of the SAC. Studies have revealed many roles for Bub1 in both mitosis and meiosis, including the localization of other SAC proteins to the kinetochore, SAC signaling, metaphase congression and the protection of sister chromatid cohesion. Recent data show striking sex specific differences in the response of germ cells to alterations in Bub1 activity. Proper Bub1 functioning is particularly important during oogenesis in preventing the generation of aneuploid gametes that can have detrimental effects on the health status of the fetus and the newborn. These data suggest that Bub1 is a master regulator of SAC and chromosomal segregation in both mitosis and meiosis. Elucidating its many essential functions in regulating proper chromosome segregation can have important consequences for preventing tumorigenesis and developmental abnormalities. © 2010 Landes Bioscience.

Murdock C.R.,University of Tennessee at Knoxville | McNutt N.W.,University of Tennessee at Knoxville | Keffer D.J.,University of Tennessee at Knoxville | Jenkins D.M.,University of Tennessee at Knoxville
Journal of the American Chemical Society | Year: 2014

A semirigid bis(1,2,4-triazole) ligand binds in a syn conformation between copper(I) chains to form a series of two-dimensional metal-organic frameworks that display a topology of fused one-dimensional metal-organic nanotubes. These anisotropic frameworks undergo two different transformations in the solid state as a function of solvation. The 2D sheet layers can expand or contract, or, more remarkably, the phenyl rings can rotate between two distinct positions. Rotation of the phenyl rings allows for the adjustment of the tube size, depending on the guest molecules present. This "gate" effect along the 1D tubes has been characterized through single-crystal X-ray diffraction. The transformations can also be followed by powder X-ray diffraction (PXRD) and solid-state 13C cross-polarization magic-angle-spinning (CP-MAS) NMR. Whereas PXRD cannot differentiate between transformations, solid-state 13C CP-MAS NMR can be employed to directly monitor phenyl rotation as a function of solvation, suggesting that this spectroscopic method is a powerful approach for monitoring breathing in this novel class of frameworks. Finally, simulations show that rotation of the phenyl ring from a parallel orientation to a perpendicular orientation occurs at the cost of framework-framework energy and that this energetic cost is offset by stronger framework-solvent interactions. © 2013 American Chemical Society.

Racial/ethnic diversity in the United States has increased significantly in recent decades, with minority groups now accounting for almost one-third of the total population. At the same time, growing diversity has spread into rural and non-metropolitan areas. Research suggests that changing diversity in the 'New South' has seen growth of non-Black communities. The question, however, is the degree to which increasing diversity equates with increasing intermixing or, alternatively, whether racial/ethnic clusters retain their prominence. This paper examines the geographic manifestations of growing racial/ethnic diversity within intra-urban context, using census-tracts as scale of analysis in the metropolitan statistical area (MSA) of Knoxville in Tennessee. The statistics used for analyzing intra-urban variations include Diversity Score, Theil Entropy Index, and Location Quotient. Tract and Block-group data for White, Black, American Indian, Asian, All Others and Hispanic are used for computing these indices. This paper concludes that diversity has increased during 1990-2000, and has dispersed into suburban counties. However, segregation and clustering for certain minority groups has also increased, in particular African-Americans still remain the most segregated and most clustered community confined to specific geographic locations. This research holds significance as local economic development patterns are very much guided by the geographic variability of human and social capital. Applied research can suggest avenues for growth and can help rebuild local communities. This paper will also contribute to literature focusing on methodological challenges in measuring diversity and its geographic manifestations. © 2011 Elsevier Ltd.

Gao Y.,University of Tennessee at Knoxville | Gao Y.,Oak Ridge National Laboratory
Journal of the Mechanics and Physics of Solids | Year: 2010

Stickslip behavior observed from nanoscale asperity friction experiments are often modeled by the one-degree-of-freedom Tomlinson model, which is unable to explain the effects of lattice structure and interface defects, or by molecular simulations which suffer temporal limitations in modeling the velocity- and temperature-dependent frictional behavior. A Peierls-type model developed in this work views the atomic frictional process as the initiation and gliding passage of dislocations with diffused cores on the interface. As a consequence of loss-of-ellipticity instability, the occurrence of stickslip behavior relies on the interaction among interface slip field, contact stress fields, and existing defects. The friction stress for commensurate interface under large contact area can be approximated from the Rice model of screw-dislocation nucleation from a planar crack tip. The spatially inhomogeneous nature of rate-limiting processes and the coupling effects between contact size and interface incommensurability are successfully determined, which cannot otherwise be tackled in the Tomlinsonmodel. © 2010 Elsevier Ltd. All rights reserved.

Shpak E.D.,University of Tennessee at Knoxville
Journal of Integrative Plant Biology | Year: 2013

Multiple receptor-like kinases (RLKs) enable intercellular communication that coordinates growth and development of plant tissues. ERECTA family receptors (ERfs) are an ancient family of leucine-rich repeat RLKs that in Arabidopsis consists of three genes: ERECTA, ERL1, and ERL2. ERfs sense secreted cysteine-rich peptides from the EPF/EPFL family and transmit the signal through a MAP kinase cascade. This review discusses the functions of ERfs in stomata development, in regulation of longitudinal growth of aboveground organs, during reproductive development, and in the shoot apical meristem. In addition the role of ERECTA in plant responses to biotic and abiotic factors is examined. copy; 2013 Institute of Botany, Chinese Academy of Sciences.

Petridis L.,Oak Ridge National Laboratory | Schulz R.,Oak Ridge National Laboratory | Schulz R.,University of Tennessee at Knoxville | Smith J.C.,Oak Ridge National Laboratory
Journal of the American Chemical Society | Year: 2011

Lignins are hydrophobic, branched polymers that regulate water conduction and provide protection against chemical and biological degradation in plant cell walls. Lignins also form a residual barrier to effective hydrolysis of plant biomass pretreated at elevated temperatures in cellulosic ethanol production. Here, the temperature-dependent structure and dynamics of individual softwood lignin polymers in aqueous solution are examined using extensive (17 μs) molecular dynamics simulations. With decreasing temperature the lignins are found to transition from mobile, extended to glassy, compact states. The polymers are composed of blobs, inside which the radius of gyration of a polymer segment is a power-law function of the number of monomers comprising it. In the low temperature states the blobs are interpermeable, the polymer does not conform to Zimm/Stockmayer theory, and branching does not lead to reduction of the polymer size, the radius of gyration being instead determined by shape anisotropy. At high temperatures the blobs become spatially separated leading to a fractal crumpled globule form. The low-temperature collapse is thermodynamically driven by the increase of the translational entropy and density fluctuations of water molecules removed from the hydration shell, thus distinguishing lignin collapse from enthalpically driven coil-globule polymer transitions and providing a thermodynamic role of hydration water density fluctuations in driving hydrophobic polymer collapse. Although hydrophobic, lignin is wetted, leading to locally enhanced chain dynamics of solvent-exposed monomers. The detailed characterization obtained here provides insight at atomic detail into processes relevant to biomass pretreatment for cellulosic ethanol production and general polymer coil-globule transition phenomena. © 2011 American Chemical Society.

Ryberg M.,University of Tennessee at Knoxville | Brandon Matheny P.,University of Tennessee at Knoxville
Proceedings of the Royal Society B: Biological Sciences | Year: 2012

The ectomycorrhizal (ECM) symbiosis is the most widespread biotrophic nutritional mode in mushroomforming fungi. ECM fungi include, though are not limited to, about 5000 described species of Agaricales from numerous, independently evolved lineages. Two central hypotheses suggest different explanations for the origin of ECM fungal diversity: (i) dual origins, initially with the Pinaceae in the Jurassic and later with angiosperms during the Late Cretaceous, and (ii) a simultaneous and convergent radiation of ECM lineages in response to cooling climate during the Palaeogene and advancing temperateECMplant communities. Neither of these hypotheses is supported here. While we demonstrate support for asynchronous origins ofECMAgaricales, the timing of such events appears to have occurred more recently than suggested by the first hypothesis, first during the Cretaceous and later during the Palaeogene. We are also unable to reject models of rate constancy, which suggests that the diversity of ECM Agaricales is not a consequence of convergent rapid radiations following evolutionary transitions from saprotrophic to ECM habits. ECM lineages of Agaricales differ not only in age, but also in rates of diversification and rate of substitution at nuclear ribosomal RNA loci. These results question the biological uniformity of the ECM guild. © 2011 The Royal Society.

Murdock C.R.,University of Tennessee at Knoxville | Jenkins D.M.,University of Tennessee at Knoxville
Journal of the American Chemical Society | Year: 2014

Employment of semirigid double-hinged di-1,2,4-triazoles has led to the synthesis of an isostructural series of metal-organic nanotubes (MONTs). The ditriazole ligands adopt a syn conformation between rigid metal chains while an appropriate anion choice provides a "capping" of the metal ions, leading to MONT formation. This approach of utilizing a variety of both semirigid ligands and metals is the first general methodology to prepare this class of 1D nanomaterial. The local geometry at the metal center depends on the metal ion employed, with Cu(I) centers adopting a tetrahedral geometry, Ag(I) centers adopting a seesaw geometry, and Cu(II) centers adopting a square-pyramidal geometry upon MONT synthesis. The pore size of the MONTs is adjusted by changing the central portion of the double-hinged ligand, allowing for a predictable method to control the pore width of the MONT. The adsorption properties of MONTs as a function of pore size revealed selective uptake of CO2 and CH4, with copper MONTs exhibiting the highest uptake. In the case of the silver MONTs, an increase in pore width improves both gas uptake and selectivity. © 2014 American Chemical Society.

Charrier R.,University of Missouri | Li Y.,University of Tennessee at Knoxville
Applied Geography | Year: 2012

Digital elevation models (DEMs) have been widely used in automated floodplain modeling to determine floodplain boundaries. However, the effects of DEM resolution and data source on floodplain delineation are not well quantified. This paper presents a case study to assess these effects from the Camp Creek Watershed, Missouri, using two sets of DEMs. One is the Light Detection and Ranging (LiDAR) DEMs resampled from 1-m to 3, 5, 10, 15, and 30-m resolutions. The other is 5, 10, and 30-m DEMs obtained from the U.S. Geological Survey (USGS). Floodplain boundaries are delineated using a combination of hydrological, hydraulic and floodplain delineation models under the Federal Emergency Management Agency's (FEMA) guideline. Model outputs including stream network, watershed and floodplain boundaries are compared to 1-m LiDAR DEM outputs (as the reference) to assess the uncertainty. Results indicate that re-sampled 3 or 5-m LiDAR DEMs produce similar streams and floodplain boundaries within 10% difference of the reference. In contrast, coarser LiDAR DEMs (such as the 10-m resolution) are more appropriate for watershed boundary delineation because higher DEM resolutions are likely more sensitive to minor topographic changes and may introduce erroneous boundaries. For different data sources, uncertainties introduced by USGS DEMs are much higher than LiDAR DEMs with a distinct relationship between uncertainties and DEM resolutions. Uncertainties of LiDAR DEMs consistently increase with decreasing resolutions, whereas similar levels of uncertainty are observed for different USGS DEM resolutions. This difference is probably due to the inherited difference in their original data source resolutions to make these two types of DEMs. © 2011 Elsevier Ltd.

King R.,University of Tennessee at Knoxville
Archives of Pathology and Laboratory Medicine | Year: 2011

Context.-Atypical lentiginous melanocytic lesions, particularly in older individuals, continue to pose a diagnostic challenge. Such lesions often show features intermediate between lentiginous nevus and melanoma in situ. We have recently defined within this group of lesions a histologic pattern of lentiginous melanoma, a slowly progressing variant of melanoma typically found on the trunk and proximal extremities of middle-aged and older individuals. Objective.-To review the clinical and histologic features of lentiginous melanoma and its histologic differential diagnosis. Data Sources.-Review of pertinent published literature and work in our laboratory. Conclusions.- Lentiginous melanoma defines a subset of slowly progressing melanoma occurring in middle-aged and older patients. It is histologically characterized by a broad atypical lentiginous growth pattern of moderately atypical melanocytes showing focal nesting and pagetoid spread without significant dermal fibroplasia or alteration of the rete ridges. Lentiginous melanoma shows significant overlap in clinical and histologic features with atypical lentiginous nevus (of the elderly). Relationship between these entities requires further investigations. Given the risk of progression to invasive melanoma, all lesions showing features of lentiginous melanoma should be treated with adequately wide excision.

Keenan S.W.,University of Tennessee at Knoxville
American Mineralogist | Year: 2016

The preservation of bone or bioapatite over geologic time has presented paleobiologists with long-standing and formidable questions. Namely, to elucidate the mechanisms, processes, rates, and depositional conditions responsible for the formation of a fossil from a once living tissue. Approaches integrating geochemistry, mineralogy, physics, hydrology, sedimentology, and taphonomy have all furthered insights into fossilization, but several fundamental gaps still remain. Notably, our limited understanding of: (1) the timing of processes during diagenesis (e.g., early and/or late), (2) the rate of bioapatite transformation into thermodynamically more stable phases, (3) the controls imparted by depositional environment, and (4) the role of (micro)biology in determining the fate of bone bioapatite (dissolution or preservation). The versatility of fossil bioapatite to provide information on the biology of extinct vertebrates rests on our ability to identify and characterize the changes that occurred to bioapatite during diagenesis. This review will evaluate our current understanding of bioapatite diagenesis and fossilization, focusing on the biogeochemical transformations that occur during diagenesis to the mineral and organic components of bone (excluding teeth and enamel), the analytical approaches applied to evaluate fossilization processes, and outline some suggestions for future promising directions. © 2016 by Walter de Gruyter Berlin/Boston 2016.

Peacock J.C.,University of Tennessee at Chattanooga | Sloan S.S.,University of Tennessee at Knoxville | Cripps B.,University of Tennessee at Chattanooga
Obesity Surgery | Year: 2014

Research has shown that some bariatric patients overestimate post-surgical exercise levels, while others struggle with negative cognitions and follow-through on intentions to exercise; however, little exists on specific barriers affecting bariatric patients' post-surgical exercise behaviors. Considering that regular exercise is a predictor of weight loss maintenance, further research is warranted. Survey methodology was utilized to assess post-operative exercise barriers as well as beneficial post-surgical exercise services among a sample of bariatric patients solicited from an online support website. Qualitative assessment of responses was completed using inductive content analysis. Higher-order themes for exercise barriers included internal, external, and no barriers; generic categories determined for internal barriers included motivational and physical barriers. Of the participants, 78 % reported at least one internal motivational barrier, and the most frequently reported subcategorical barrier was time (28 %); physical barriers were reported related to surgery (9 %) or other chronic conditions (19 %). Higher-order themes for exercise services included positive descriptions such as benefits from exercise prescription as well as the importance of facilities and individuals, while negative descriptions included no services available or services that were unhelpful. Participants cited the benefit of community-based facilities, so providers might consider partnering with local professionals to deliver exercise services. Staff should be aware of physical barriers specific to bariatric populations including issues with post-surgical stamina and chronic comorbid conditions in order to provide appropriate exercise prescription. In addition, as motivational and time barriers occur frequently, providers should be well-trained on how to help patients overcome these impediments to exercise maintenance. © 2013 Springer Science+Business Media New York.

Vogt F.,University of Tennessee at Knoxville
Journal of Chemometrics | Year: 2015

Hard modeling of nonlinear chemical or biological systems is highly relevant as a model function together with values for model parameters provides insights in the systems' functionalities. Deriving values for said model parameters via nonlinear regression, however, is challenging as usually one of the numerous local minima of the sum-of-squared errors (SSEs) is determined; furthermore, for different starting points, different minima may be found. Thus, nonlinear regression is prone to low accuracy and low reproducibility. Therefore, there is a need for a generally applicable, automated initialization of nonlinear least squares algorithms, which reaches a good, reproducible solution after spending a reasonable computation time probing the SSE-hypersurface. For this purpose, a three-step methodology is presented in this study. First, the SSE-hypersurface is randomly probed in order to estimate probability density functions of initial model parameter that generally lead to an accurate fit solution. Second, these probability density functions then guide a high-resolution sampling of the SSE-hypersurface. This second probing focuses on those model parameter ranges that are likely to produce a low SSE. As the probing continues, the most appropriate initial guess is retained and eventually utilized in a subsequent nonlinear regression. It is shown that this "guided random search" derives considerably better regression solutions than linearization of model functions, which has so far been considered the best-case scenario. Examples from infrared spectroscopy, cell culture monitoring, reaction kinetics, and image analyses demonstrate the broad and successful applicability of this novel method. © 2014 John Wiley & Sons, Ltd.

Lee S.,University of Tennessee at Knoxville | Matejkowski J.,Section on Law and Ethics Treatment Research Institute
Administration and Policy in Mental Health and Mental Health Services Research | Year: 2012

Since the Welfare Reform Act of 1996, citizenship status has become an important consideration in mental health service utilization due to the restrictions on federal healthcare benefits for noncitizens living in the U.S. Using a nationally representative sample of Latinos and Asians, we examined the extent to which U.S. citizenship status was related to rates of mental health service utilization. We also identified several predictors of mental health service utilization among noncitizens. Noncitizens were about 40% less likely than U.S.-born citizens to use any mental health services. Findings are discussed in the context of healthcare policy and recent healthcare reform. © 2011 Springer Science+Business Media, LLC.

Gritti F.,University of Tennessee at Knoxville | Tanaka N.,GL Sciences Inc. | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2012

The gradient elution performance of narrow-bore 2.3mm×50mm (N733) and wider bore 3.2mm×50mm (N648 and N655) prototype silica monolithic columns was investigated and compared to the performance of commercially available columns packed with sub-2μm fully porous particles (2.1mm×50mm, 1.7μm BEH-C 18, Waters) and sub-3μm superficially porous particles (2.1mm×50mm, 2.7μm Halo-ES-Peptide-C 18 (AMT), 1.7 and 2.6μm Kinetex-C 18, Phenomenex). Results show that the two wide monolithic columns show peak capacities similar to the one measured for the Kinetex column. In contrast, the narrow-bore monolithic column delivers a lower performance (-30%) than the BEH, the Halo and the Kinetex columns. This work stresses out the importance of reducing the extra-column band broadening contribution of HPLC instruments when short 2.1mm I.D. columns are used. The part of the instrument contribution originating downstream the column is important for all compounds; the one originating upstream the column is significant only for weakly retained compounds. © 2012 Elsevier B.V.

Sarles S.A.,University of Tennessee at Knoxville
Smart Materials and Structures | Year: 2013

The droplet interface bilayer (DIB) is a simple technique for constructing a stable lipid bilayer at the interface of two lipid-encased water droplets submerged in oil. Networks of DIBs formed by connecting more than two droplets constitute a new form of modular biomolecular smart material, where the transduction properties of a single lipid bilayer can affect the actions performed at other interface bilayers in the network via diffusion through the aqueous environments of shared droplet connections. The passive electrical properties of a lipid bilayer and the arrangement of droplets that determine the paths for transport in the network require specific electrical control to stimulate and interrogate each bilayer. Here, we explore the use of virtual ground for electrodes inserted into specific droplets in the network and employ a multichannel patch clamp amplifier to characterize bilayer formation and ion-channel activity in a serial DIB array. Analysis of serial connections of DIBs is discussed to understand how assigning electrode connections to the measurement device can be used to measure activity across all lipid membranes within a network. Serial arrays of DIBs are assembled using the regulated attachment method within a multi-compartment flexible substrate, and wire-type electrodes inserted into each droplet compartment of the substrate enable the application of voltage and measurement of current in each droplet in the array. © 2013 IOP Publishing Ltd.

Akcay E.,University of Tennessee at Knoxville
Journal of Theoretical Biology | Year: 2012

In many biological and social interactions, individuals with private information have incentives to misrepresent their information. A prominent example is when offspring know their need or condition but the parents do not. Theory showed that signal costs can ensure truthful communication in such situations, but further studies have cast in doubt whether empirically measured costs are high enough to sustain honesty, and whether the costly signaling equilibrium represents a fitness advantage over non-signaling. Here, I tackle these issues with a model of signaling that takes place at the behavioral time-scale through dynamic responses of individuals to each other. I then embed this behavioral model in an evolutionary one that asks how the decision rules of the parent and offspring evolve in response to the trade-off between signal costs and the costs of provisioning. I find that a non-costly honest signaling equilibrium can evolve when relatedness between siblings is above a certain threshold. This threshold is lower when (i) offspring get satiated more quickly, (ii) the cost of provisioning to the parent escalates less rapidly, or (iii) the variation in offspring need is higher. These results provide a potential resolution to the apparent paradox of costly begging. I also discuss the relation between costly signaling and mechanism design theories. © 2011 Elsevier Ltd.

Hewezi T.,University of Tennessee at Knoxville
Plant Physiology | Year: 2015

Plant-parasitic cyst and root-knot nematodes synthesize and secrete a suite of effector proteins into infected host cells and tissues. These effectors are the major virulence determinants mediating the transformation of normal root cells into specialized feeding structures. Compelling evidence indicates that these effectors directly hijack or manipulate refined host physiological processes to promote the successful parasitism of host plants. Here, we provide an update on recent progress in elucidating the molecular functions of nematode effectors. In particular, we emphasize how nematode effectors modify plant cell wall structure, mimic the activity of host proteins, alter auxin signaling, and subvert defense signaling and immune responses. In addition, we discuss the emerging evidence suggesting that nematode effectors target and recruit various components of host posttranslational machinery in order to perturb the host signaling networks required for immunity and to regulate their own activity and subcellular localization. © 2015 American Society of Plant Biologists. All rights reserved.

Langley-Shirley N.,University of Tennessee at Knoxville | Jantz R.L.,University of Tennessee at Knoxville
Journal of Forensic Sciences | Year: 2010

Clavicles from 1289 individuals from cohorts spanning the 20th century were scored with two scoring systems. Transition analysis and Bayesian statistics were used to obtain robust age ranges that are less sensitive to the effects of age mimicry and developmental outliers than age ranges obtained using a percentile approach. Observer error tests showed that a simple three-phase scoring system proved the least subjective, while retaining accuracy levels. Additionally, significant sexual dimorphism was detected in the onset of fusion, with women commencing fusion at least a year earlier than men (women transition to fusion at approximately 15 years of age and men at 16 years). Significant secular trends were apparent in the onset of skeletal maturation, with modern Americans transitioning to fusion approximately 4 years earlier than early 20th century Americans and 3.5 years earlier than Korean War era Americans. These results underscore the importance of using modern standards to estimate age in modern individuals. © 2010 American Academy of Forensic Sciences.

Barber B.K.,University of Tennessee at Knoxville
Journal of Child Psychology and Psychiatry and Allied Disciplines | Year: 2013

Aims and method Drawing on empirical studies and literature reviews, this paper aims to clarify and qualify the relevance of resilience to youth experiencing political conflict. It focuses on the discordance between expectations of widespread dysfunction among conflict-affected youth and a body of empirical evidence that does not confirm these expectations. Findings The expectation for widespread dysfunction appears exaggerated, relying as it does on low correlations and on presumptions of universal response to adversity. Such a position ignores cultural differences in understanding and responding to adversity, and in the specific case of political conflict, it does not account for the critical role of ideologies and meaning systems that underlie the political conflict and shape a young people's interpretation of the conflict, and their exposure, participation, and processing of experiences. With respect to empirical evidence, the findings must be viewed as tentative given the primitive nature of research designs: namely, concentration on violence exposure as the primary risk factor, at the expense of recognizing war's impact on the broader ecology of youth's lives, including disruptions to key economic, social, and political resources; priority given to psychopathology in the assessment of youth functioning, rather than holistic assessments that would include social and institutional functioning and fit with cultural and normative expectations and transitions; and heavy reliance on cross-sectional, rather than longitudinal, studies. Conclusions Researchers and practitioners interested in employing resilience as a guiding construct will face such questions: Is resilience predicated on evidence of competent functioning across the breadth of risks associated with political conflict, across most or all domains of functioning, and/or across time? In reality, youth resilience amidst political conflict is likely a complex package of better and poorer functioning that varies over time and in direct relationship to social, economic, and political opportunities. Addressing this complexity will complicate the definition of resilience, but it confronts the ambiguities and limitations of work in cross-cultural contexts. © 2013 The Authors. Journal of Child Psychology and Psychiatry © 2013 Association for Child and Adolescent Mental Health.

Adhikari S.,University of Tennessee at Knoxville | Li F.,University of Tennessee at Knoxville
IEEE Transactions on Smart Grid | Year: 2014

The microgrid concept allows small distributed energy resources (DERs) to act in a coordinated manner to provide a necessary amount of active power and ancillary service when required. This paper proposes an approach of coordinated and integrated control of solar PV generators with the maximum power point tracking (MPPT) control and battery storage control to provide voltage and frequency (V-f) support to an islanded microgrid. Also, active and nonactive/reactive power (P-Q) control with solar PV, MPPT and battery storage is proposed for the grid connected mode. The control strategies show effective coordination between inverter V-f (or P-Q) control, MPPT control, and energy storage charging and discharging control. The paper also shows an effective coordination among participating microresources while considering the case of changing irradiance and battery state of charge (SOC) constraint. The simulation studies are carried out with the IEEE 13-bus feeder test system in grid connected and islanded microgrid modes. The results clearly verify the effectiveness of proposed control methods. The simulations are carried out in Matlab and Simpowersystems. © 2010-2012 IEEE.

Fleming J.T.,University of Tennessee at Knoxville
Advances in Biochemical Engineering/Biotechnology | Year: 2010

The direct interfacing of living cells with inorganic electronic materials, components or systems has led to the development of two broad categories of devices that can (1) transduce biochemical signals generated by biological components into electrical signals and (2) transduce electronically generated signals into biochemical signals. The first category of devices permits the monitoring of living cells, the second, enables control of cellular processes. This review will survey this exciting area with emphasis on the fundamental issues and obstacles faced by researchers. Devices and applications that use both prokaryotic (microbial) and eukaryotic (mammalian) cells will be covered. Individual devices described include microbial biofuel cells that produce electricity, bioelectrical reactors that enable electronic control of cellular metabolism, living cell biosensors for the detection of chemicals and devices that permit monitoring and control of mammalian physiology. © Springer-Verlag Berlin Heidelberg 2009.

Ripp S.,University of Tennessee at Knoxville
Advances in Biochemical Engineering/Biotechnology | Year: 2010

Considered the most abundant organism on Earth, at a population approaching 1031, bacteriophage, or phage for short, mediate interactions with myriad bacterial hosts that has for decades been exploited in phage typing schemes for signature identification of clinical, food-borne, and water-borne pathogens. With over 5,000 phage being morphologically characterized and grouped as to susceptible host, there exists an enormous cache of bacterial-specific sensors that has more recently been incorporated into novel bio-recognition assays with heightened sensitivity, specificity, and speed. These assays take many forms, ranging from straightforward visualization of labeled phage as they attach to their specific bacterial hosts to reporter phage that genetically deposit trackable signals within their bacterial hosts to the detection of progeny phage or other uniquely identifiable elements released from infected host cells. A comprehensive review of these and other phage-based detection assays, as directed towards the detection and monitoring of bacterial pathogens, will be provided in this chapter. © Springer-Verlag Berlin Heidelberg 2009.

Hinde R.J.,University of Tennessee at Knoxville
Computer Physics Communications | Year: 2011

We describe QSATS, a parallel code for performing variational path integral simulations of the quantum mechanical ground state of monatomic solids. QSATS is designed to treat Boltzmann quantum solids, in which individual atoms are permanently associated with distinguishable crystal lattice sites and undergo large-amplitude zero-point motions around these sites. We demonstrate the capabilities of QSATS by using it to compute the total energy and potential energy of hexagonal close packed solid 4He at the density ρ=4.61421×10-3a0-3. Program summary: Program title: QSATS Catalogue identifier: AEJE-v1-0 Program summary URL: summaries/AEJE-v1-0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, No. of lines in distributed program, including test data, etc.: 7329 No. of bytes in distributed program, including test data, etc.: 61 685 Distribution format: tar.gz Programming language: Fortran 77. Computer: QSATS should execute on any distributed parallel computing system that has the Message Passing Interface (MPI) [1] libraries installed. Operating system: Unix or Linux. Has the code been vectorized or parallelized?: Yes, parallelized using MPI [1]. RAM: The memory requirements of QSATS depend on both the number of atoms in the crystal and the number of replicas in the variational path integral chain. For parameter sets A and C (described in the long write-up), approximately 4.5 Mbytes and 12 Mbytes, respectively, are required for data storage by QSATS (exclusive of the executable code). Classification: 7.7, 16.13. External routines: Message Passing Interface (MPI) [1] Nature of problem: QSATS simulates the quantum mechanical ground state for a monatomic crystal characterized by large-amplitude zero-point motions of individual (distinguishable) atoms around their nominal lattice sites. Solution method: QSATS employs variational path integral quantum Monte Carlo techniques to project the system's ground state wave function out of a suitably-chosen trial wave function. Restrictions: QSATS neglects quantum statistical effects associated with the exchange of identical particles. As distributed, QSATS assumes that the potential energy function for the crystal is a pairwise additive sum of atom-atom interactions. Additional comments: An auxiliary program, ELOC, is provided that uses the output generated by QSATS to compute both the crystal's ground state energy and the expectation value of the crystal's potential energy. End users can modify ELOC as needed to compute the expectation value of other coordinate-space observables. Running time: QSATS requires roughly 3 hours to run a simulation using parameter set A on a cluster of 12 Xeon processors with clock speed 2.8 GHz. Roughly 15 hours are needed to run a simulation using parameter set C on the same cluster. References: For information about MPI, visit © 2011 Elsevier B.V. All rights reserved.

Black E.A.,University of Tennessee at Knoxville
The Iowa orthopaedic journal | Year: 2011

Open fractures of the pelvis remain a devastating injury with a high mortality and morbidity. Such injuries require an aggressive treatment plan and the coordination of trauma and orthopaedic surgeons to achieve the best outcomes. We report our experience at the University of Tennessee Medical Center at Knoxville with open pelvic fractures over the last ten years. After IRB and institutional approval, we reviewed patients admitted with a diagnosis of open fracture of the pelvis from 1999 to 2009. Demographic and admission data were recorded in the trauma registry (TRACS) of the Level I Trauma Center, serving the 1.2 million people living in the regions of east Tennessee, western North Carolina and southeastern Kentucky. Data on fractures were obtained from review of the medical records and radiographs within the chart. There were 3053 pelvic fractures from January 1999 to December 2009. There were 231 deaths in this group (6%) and ages ranged from 18 to 89 years old and Injury Severity Scores ranged from 4 to 75, with a mean of 18.3. Seventy five percent of patients were able to be discharged home. Fifty-two fractures were open. There were 43 men and the mean age was 39 years old. Average ISS was 23 and ranged from 5 to 50. There were 10 deaths (19%) and eight patients underwent angioembolization for control of bleeding (3 deaths). Motorcycle crashes were the most frequent cause of an open fracture, with lateral compression injuries representing 71%. A defined algorithm for fracture management has been in place and employed to assure adequate resuscitation and fracture care and is presented. Open pelvic fractures are usually the result of a high energy transfer, and convey a high morbidity and mortality. A defined resuscitation and fixation strategy improves outcome from historical reports. Injuries from penetrating mechanisms are associated with less morbidity and lower mortality.

Bland W.,University of Tennessee at Knoxville
Proceedings - 12th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing, CCGrid 2012 | Year: 2012

As recent research has demonstrated, it is becoming a necessity for large scale applications to have the ability to tolerate process failure during an execution. As the number of processes increases, checkpoint/restart fault tolerance approaches requiring large concurrent state check pointing become untenable and radically new methods to address fault tolerance are needed. This work addresses these challenges by proposing a novel approach to a minimalistic fault discovery and management model. Such a model allows application to run to completion despite fail-stop failures. As a proof of concept, in addition to the proposed fault tolerance model, an implementation in the context of the Open MPI library is provided, evaluated and analyzed. © 2012 IEEE.

Bose B.K.,University of Tennessee at Knoxville
IEEE Transactions on Industrial Electronics | Year: 2013

Power electronics technology has gained significant maturity after several decades of dynamic evolution of power semiconductor devices, converters, pulse width modulation (PWM) techniques, electrical machines, motor drives, advanced control, and simulation techniques. According to the estimate of the Electric Power Research Institute, roughly 70% of electrical energy in the USA now flows through power electronics, which will eventually grow to 100%. In the 21st century, we expect to see the tremendous impact of power electronics not only in global industrialization and general energy systems, but also in energy saving, renewable energy systems, and electric/hybrid vehicles. The resulting impact in mitigating climate change problems is expected to be enormous. This paper, in the beginning, will discuss the global energy scenario, climate change problems, and the methods of their mitigation. Then, it will discuss the impact of power electronics in energy saving, renewable energy systems, bulk energy storage, and electric/hybrid vehicles. Finally, it will review several example applications before coming to conclusion and future prognosis. © 1982-2012 IEEE.

Kuo W.,City University of Hong Kong | Zhu X.,University of Tennessee at Knoxville
IEEE Transactions on Reliability | Year: 2012

Many importance measures have been proposed with respect to the diverse considerations of system performance, reflecting different probabilistic interpretations and potential applications. This paper studies importance measures in reliability, including their definitions, probabilistic interpretations, properties, computations, and comparability. It categorizes importance measures into the structure, reliability, and lifetime types based on the knowledge for determining them. It covers importance measures of individual components, and ones of pairs and groups of components. It also investigates importance measures in consecutive-k-out-of-n systems. © 2012 IEEE.

Kuo W.,City University of Hong Kong | Zhu X.,University of Tennessee at Knoxville
IEEE Transactions on Reliability | Year: 2012

To identify the critical components or sets of components in a system, various importance measures have been proposed with different probabilistic perspectives and applications. Many of these importance measures are actually related to each other in some ways. This paper summarizes the importance measures in reliability, and presents relations and comparisons among them, focusing on their interrelations to the B-importance, the dominant relations among them, the dual relations, their performances in typical systems, and their computations. The early versions of the importance measures are for binary coherent systems, while the recent research is not limited to this type of system. This paper investigates the extensions of importance measures in noncoherent systems, multistate systems, continuum systems, and repairable systems. © 2012 IEEE.

White J.B.,U.S. National Center for Atmospheric Research | Dongarra J.J.,University of Tennessee at Knoxville
Journal of Computational Physics | Year: 2011

Current climate models have a limited ability to increase spatial resolution because numerical stability requires the time step to decrease. We describe a semi-Lagrangian method for tracer transport that is stable for arbitrary Courant numbers, and we test a parallel implementation discretized on the cubed sphere. The method includes a fixer that conserves mass and constrains tracers to a physical range of values. The method shows third-order convergence and maintains nonlinear tracer correlations to second order. It shows optimal accuracy at Courant numbers of 10-20, more than an order of magnitude higher than explicit methods. We present parallel performance in terms of strong scaling, weak scaling, and spatial scaling (where the time step stays constant while the resolution increases). For a 0.2° test with 100 tracers, the implementation scales efficiently to 10,000 MPI tasks. © 2011 Elsevier Inc.

Takir D.,University of Tennessee at Knoxville | Emery J.P.,University of Tennessee at Knoxville
Icarus | Year: 2012

This paper examines the distribution and the abundance of hydrated minerals (any mineral that contains H 2O or OH) on outer Main Belt asteroids spanning the 2.5

Liu G.,University of Tennessee at Knoxville | Tomsovic K.,University of Tennessee at Knoxville
Electric Power Systems Research | Year: 2014

It has been widely accepted that demand response will play an important role in reliable and economic operation of future power systems and electricity markets. Demand response can not only influence the prices in the energy market by demand shifting, but also participate in the reserve market. In this paper, we propose a full model of demand response in which demand flexibility is fully utilized by price responsive shiftable demand bids in energy market as well as spinning reserve bids in reserve market. A co-optimized day-ahead energy and spinning reserve market is proposed to minimize the expected net cost under all credible system states, i.e., expected total cost of operation minus total benefit of demand, and solved by mixed integer linear programming. Numerical simulation results on the IEEE Reliability Test System show effectiveness of this model. Compared to conventional demand shifting bids, the proposed full demand response model can further reduce committed capacity from generators, starting up and shutting down of units and the overall system operating costs. © 2014 Elsevier B.V.

Davidson P.M.,University of Tennessee at Knoxville | Critzer F.J.,University of Tennessee at Knoxville | Matthew Taylor T.,Texas A&M University
Annual Review of Food Science and Technology | Year: 2013

Natural antimicrobials are gaining increased interest from researchers and food manufacturers alike seeking to discover label-friendly alternatives to the widely implemented synthetic compounds. Naturally occurring antimicrobials can be applied directly to food to protect food quality, extend food shelf life by inhibiting or inactivating spoilage microorganisms, and improve food safety by inhibiting or inactivating food-borne pathogens. There are a great number of natural antimicrobials derived from animal, plant, and microbial sources. This manuscript reviews their efficacy against spoilage and pathogenic organisms, their methods of evaluation, and their application in various foods as well as the development of novel delivery systems and incorporation with other hurdles. Copyright © 2013 by Annual Reviews.

Near T.J.,Yale University | Keck B.P.,University of Tennessee at Knoxville
Molecular Phylogenetics and Evolution | Year: 2013

Investigations into the phylogenetics of closely related animal species are dominated by the use of mitochondrial DNA (mtDNA) sequence data. However, the near-ubiquitous use of mtDNA to infer phylogeny among closely related animal lineages is tempered by an increasing number of studies that document high rates of transfer of mtDNA genomes among closely related species through hybridization, leading to substantial discordance between phylogenies inferred from mtDNA and nuclear gene sequences. In addition, the recent development of methods that simultaneously infer a species phylogeny and estimate divergence times, while accounting for incongruence among individual gene trees, has ushered in a new era in the investigation of phylogeny among closely related species. In this study we assess if DNA sequence data sampled from a modest number of nuclear genes can resolve relationships of a species-rich clade of North American freshwater teleost fishes, the darters. We articulate and expand on a recently introduced method to infer a time-calibrated multi-species coalescent phylogeny using the computer program *BEAST. Our analyses result in well-resolved and strongly supported time-calibrated darter species tree. Contrary to the expectation that mtDNA will provide greater phylogenetic resolution than nuclear gene data; the darter species tree inferred exclusively from nuclear genes exhibits a higher frequency of strongly supported nodes than the mtDNA time-calibrated gene tree. © 2012 Elsevier Inc.

Vivekananthan C.,Queensland University of Technology | Mishra Y.,Queensland University of Technology | Ledwich G.,Queensland University of Technology | Li F.,University of Tennessee at Knoxville
IEEE Transactions on Smart Grid | Year: 2014

This paper proposes a reward based demand response algorithm for residential customers to shave network peaks. Customer survey information is used to calculate various criteria indices reflecting their priority and flexibility. Criteria indices and sensitivity based house ranking is used for appropriate load selection in the feeder for demand response. Customer Rewards (CR) are paid based on load shift and voltage improvement due to load adjustment. The proposed algorithm can be deployed in residential distribution networks using a two-level hierarchical control scheme. Realistic residential load model consisting of non-controllable and controllable appliances is considered in this study. The effectiveness of the proposed demand response scheme on the annual load growth of the feeder is also investigated. Simulation results show that reduced peak demand, improved network voltage performance, and customer satisfaction can be achieved. © 2014 IEEE.

Fernandez P.,University of Tennessee at Knoxville
Library Hi Tech News | Year: 2011

Purpose: The purpose of this paper is to highlight how the open-source bibliographic management program Zotero harnesses Web 2.0 features to make library resources more accessible to casual users without sacrificing advanced features. This reduces the barriers understanding library resources and provides additional functionality when organizing information resources. Design/methodology/approach: The paper reviews select aspects of the program to illustrate how it can be used by patrons and information professionals, and why information professionals should be aware of it. Findings: Zotero has some limitations, but succeeds in meeting the information management needs of a wide variety of users, particularly users who use online resources. Originality/value: This paper is of interest to information professionals seeking free software that can make managing bibliographic information easier for themselves and their patrons. © Emerald Group Publishing Limited.

Nolt J.,University of Tennessee at Knoxville
Wiley Interdisciplinary Reviews: Climate Change | Year: 2011

Anthropogenic climate change may contribute to a mass extinction that would leave biodiversity depleted for millions of years-quite possibly longer than the duration of the human species. Such effects are arguably of ethical concern, but because established ethical theories are anthropocentric-that is, focused on the relatively short-term interests of human beings-they offer no guidance on such vast temporal scales. There has been significant work in recent decades in both longer-term intergenerational anthropocentric climate ethics and near-term nonanthropocentric ethics, but so far these novel developments have not been integrated into a long-term nonanthropocentric climate ethic. This article considers prospects for the development and justification of such an ethic, difficulties it would face, and its relevance to climate policy. © 2011 John Wiley & Sons, Ltd.

Li Y.,National Health Research Institute | Parker L.E.,University of Tennessee at Knoxville
Information Fusion | Year: 2014

Missing data is common in Wireless Sensor Networks (WSNs), especially with multi-hop communications. There are many reasons for this phenomenon, such as unstable wireless communications, synchronization issues, and unreliable sensors. Unfortunately, missing data creates a number of problems for WSNs. First, since most sensor nodes in the network are battery-powered, it is too expensive to have the nodes re-transmit missing data across the network. Data re-transmission may also cause time delays when detecting abnormal changes in an environment. Furthermore, localized reasoning techniques on sensor nodes (such as machine learning algorithms to classify states of the environment) are generally not robust enough to handle missing data. Since sensor data collected by a WSN is generally correlated in time and space, we illustrate how replacing missing sensor values with spatially and temporally correlated sensor values can significantly improve the network's performance. However, our studies show that it is important to determine which nodes are spatially and temporally correlated with each other. Simple techniques based on Euclidean distance are not sufficient for complex environmental deployments. Thus, we have developed a novel Nearest Neighbor (NN) imputation method that estimates missing data in WSNs by learning spatial and temporal correlations between sensor nodes. To improve the search time, we utilize a kd-tree data structure, which is a non-parametric, data-driven binary search tree. Instead of using traditional mean and variance of each dimension for kd-tree construction, and Euclidean distance for kd-tree search, we use weighted variances and weighted Euclidean distances based on measured percentages of missing data. We have evaluated this approach through experiments on sensor data from a volcano dataset collected by a network of Crossbow motes, as well as experiments using sensor data from a highway traffic monitoring application. Our experimental results show that our proposed K-NN imputation method has a competitive accuracy with state-of-the-art Expectation-Maximization (EM) techniques, while using much simpler computational techniques, thus making it suitable for use in resource-constrained WSNs. © 2013 Elsevier Ltd. All rights reserved.

Zhang Y.,University of Tennessee at Knoxville | Parker L.E.,University of Tennessee at Knoxville
IEEE Transactions on Robotics | Year: 2013

While most previous research on forming coalitions mainly concentrates on loosely coupled multirobot tasks, a more challenging problem is to address tightly coupled multirobot tasks that involve close robot coordinations, which often require capability sharing. General methods for autonomous capability sharing have been shown to greatly improve the flexibility of distributed systems. However, in addition to the interaction constraints between the robots and the environment as required by the tasks, these methods may introduce additional interaction constraints between the robots based on how the capabilities are shared. The satisfiability of these constraints in the current situation determines the feasibility of the potential coalitions. To achieve system autonomy, the ability to identify the potential coalitions that are feasible for task execution is critical. In this paper, we demonstrate a general approach that incorporates this capability based on the ASyMTRe architecture. The extended architecture, which is called IQ-ASyMTRe, is able to find coalitions in which these required constraints are satisfied. When used to form coalitions, IQ-ASyMTRe sets up only feasible coalitions, thus enabling tasks to be executed autonomously. We formally present the new architecture and prove that it is sound and complete, given certain assumptions. Simulations and experimental results are provided for different applications in which the robots are able to flexibly form coalitions that are ready to execute. © 2004-2012 IEEE.

Simberloff D.,University of Tennessee at Knoxville
Environmental Ethics | Year: 2012

Non-native species are implicated in many ecological and economic problems, and the field of invasion biology has burgeoned in response to this fact. However, classification, terminology, and management of non-native species generate controversies and even calls for abolition of the field. The fact that the basis for disputes is differing worldviews rather than simply interpretation of biological observations suggests that resolving arguments about non-native species will be difficult, independently of questions about the operational tractability of proposed courses of action.

Rathore K.,University of Tennessee at Knoxville | Wang H.-C.R.,University of Tennessee at Knoxville
Molecular Carcinogenesis | Year: 2012

Sporadic breast cancers are mainly attributable to long-term exposure to environmental factors, via a multi-year, multi-step, and multi-path process of tumorigenesis involving cumulative genetic and epigenetic alterations in the chronic carcinogenesis of breast cells from a non-cancerous stage to precancerous and cancerous stages. Epidemiologic and experimental studies have suggested that green tea components may be used as preventive agents for breast cancer control. In our research, we have developed a cellular model that mimics breast cell carcinogenesis chronically induced by cumulative exposures to low doses of environmental carcinogens. In this study, we used our chronic carcinogenesis model as a target system to investigate the activity of green tea catechin extract (GTC) at non-cytotoxic levels in intervention of cellular carcinogenesis induced by cumulative exposures to pico-molar 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (B[a]P). We identified that GTC, at a non-cytotoxic, physiologically achievable concentration of 2.5μg/mL, was effective in suppressing NNK- and B[a]P-induced cellular carcinogenesis, as measured by reduction of the acquired cancer-associated properties of reduced dependence on growth factors, anchorage-independent growth, increased cell mobility, and acinar-conformational disruption. We also detected that intervention of carcinogen-induced elevation of reactive oxygen species (ROS), increase of cell proliferation, activation of the ERK pathway, DNA damage, and changes in gene expression may account for the mechanisms of GTC's preventive activity. Thus, GTC may be used in dietary and chemoprevention of breast cell carcinogenesis associated with long-term exposure to low doses of environmental carcinogens. © 2011 Wiley Periodicals, Inc.

Woo W.,Korea Atomic Energy Research Institute | Choo H.,University of Tennessee at Knoxville
Science and Technology of Welding and Joining | Year: 2011

The influence of friction stir welding (FSW) on changes in microstructures has been studied extensively. In particular, the microstructural softening, which is manifested as a significant reduction in the hardness, tensile strength and residual stress, is one of the most significant issues. Here, we provide a brief review of the dominant softening mechanisms in FSW aluminium and magnesium alloys available in the literature. In particular, a direct comparison between a heat treatable Al 6061-T6 alloy and an AZ31B Mg alloy is presented to highlight key differences in the underlying mechanisms responsible for the apparently similar softening behaviour. The present study shows that the softening occurs in the wide region of the FSW Al 6061-T6 alloy due to the dissolution of the strengthening precipitates, while it happens mostly within the stir zone due to the localised texture variations in the FSW Mg AZ31B alloy. These softening behaviours are clearly represented in the residual stress profiles. © 2011 Institute of Materials, Minerals and Mining.

Kovac J.,University of Tennessee at Knoxville
Science and Engineering Ethics | Year: 2013

This article considers the ethical aspects of the question: should a scientist engage in war-related research, particularly use-inspired or applied research directed at the development of the means for the better waging of war? Because scientists are simultaneously professionals, citizens of a particular country, and human beings, they are subject to conflicting moral and practical demands. There are three major philosophical views concerning the morality of war that are relevant to this discussion: realism, just war theory and pacifism. In addition, the requirements of professional codes of ethics and common morality contribute to an ethical analysis of the involvement of scientists and engineers in war-related research and technology. Because modern total warfare, which is facilitated by the work of scientists and engineers, results in the inevitable killing of innocents, it follows that most, if not all, war-related research should be considered at least as morally suspect and probably as morally prohibited. © 2012 Springer Science+Business Media B.V.

Singh V.,University of Tennessee at Knoxville
GROUP'12 - Proceedings of the ACM 2012 International Conference on Support Group Work | Year: 2012

In this paper we present results of an NSF funded project on exploring and understanding cyber learning that happens in online open source software (OSS) communities for technical support. We look across multiple OSS support communities (Firefox, Java, and Koha) to understand the behavior of newcomers in these communities, the role that the community response plays in their continued participation and newcomer best practices. We found that newcomers are not a homogenous group and majority of them display "model" behavior. We also found out that community response is critical for continued participation of newcomers. In our dataset, almost all non returning newcomers can be attributed to receiving no reply or a condescending reply from the community. We found that one third of newcomers' transition into a role of help givers in the community and demonstrate evidence of learning. We also highlight best practices for newcomers to be successful in these online communities. Copyright © 2012 by the Association for Computing Machinery, Inc. (ACM).

Burghardt G.M.,University of Tennessee at Knoxville
Current Biology | Year: 2015

In this quick guide, Gordon Burghardt considers the criteria for ascribing a particular animal behavior as "play", and in particular the evidence for play in fishes, frogs and reptiles. © 2015 Elsevier Ltd. All rights reserved.

Williams J.H.,University of Tennessee at Knoxville
AoB PLANTS | Year: 2012

Background and aims: The pollination to fertilization process (progamic phase) is thought to have become greatly abbreviated with the origin of flowering plants. In order to understand what developmental mechanisms enabled the speeding of fertilization, comparative data are needed from across the group, especially from early-divergent lineages. I studied the pollen germination process of Austrobaileya scandens, a perennial vine endemic to the Wet Tropics area of northeastern Queensland, Australia, and a member of the ancient angiosperm lineage, Austrobaileyales. Methodology: I used in vivo and in vitro hand pollinations and timed collections to study development from late pollen maturation to just after germination. Then I compared the contribution of pollen germination timing to progamic phase duration in 131 angiosperm species (65 families). Principal findings: Mature pollen of Austrobaileya was bicellular, starchless and moderately dehydrated-water content was 31.5 % by weight and volume increased by 57.9 % upon hydration. A callose layer in the inner intine appeared only after pollination. In vivo pollen germination followed a logarithmic curve, rising from 28 % at 1 hour after pollination (hap) to 97 % at 12 hap (R2 = 0.98). Sufficient pollen germination to fertilize all ovules was predicted to have occurred within 62 min. Across angiosperms, pollen germination ranged from 1 min to >60 h long and required 8.3±9.8 % of the total duration of the progamic phase. Significance: Pollen of Austrobaileya has many plesiomorphic features that are thought to prolong germination. Yet its germination is quite fast for species with desiccation-tolerant pollen (range: <1 to 60 h). Austrobaileya and other early-divergent angiosperms have relatively rapid pollen germination and short progamic phases, comparable to those of many insect-pollinated monocots and eudicots. These results suggest that both the pollen germination and pollen tube growth periods were marked by acceleration of developmental processes early in angiosperm history. © The Authors 2012.

Nunez M.A.,University of Tennessee at Knoxville | Nunez M.A.,University of Central Florida | Medley K.A.,University of Central Florida
Diversity and Distributions | Year: 2011

Aim Explaining why some invasions fail while others succeed is a prevailing question in invasion biology. Different factors have been proposed to explain the success or failure of exotics. Evidence suggests that climate similarities may be crucial. We tested this using 12 species of the genus Pinus that have been widely planted and shown to be highly invasive. Pinus is among the best-studied group of exotic species and one that has been widely introduced world-wide, so we were able to obtain data on invasive and non-invasive introductions (i.e. unsuccessful invasions; areas where after many decades of self-sowing seeds there is no invasion). Location World-wide. Methods We developed species distribution models for native ranges using a maximum entropy algorithm and projected them across the globe. We tested whether climate-based models were able to predict both invasive and non-invasive introductions. Results Appropriate climatic conditions seem to be required for these long-lived species to invade because climates accurately predicted invasions. However, climate matching is necessary, but not sufficient to predict the fate of an introduction because most non-invasive introductions were predicted to have triggered an invasion. Main conclusions Other factors, possibly including biotic components, may be the key to explaining why some introductions do not become invasions, because many areas where Pinus is not invading were predicted to be suitable for invasion based solely on climate. © 2011 Blackwell Publishing Ltd.

Yen S.T.,University of Tennessee at Knoxville
Food Policy | Year: 2010

Nutritional effects of participation by young children in the Supplemental Nutrition Assistance Program (SNAP) and the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) in the United States are investigated. A system of nutrient equations with dual endogenous programs is estimated by the maximum-likelihood procedure. WIC is found to increase the intakes of three of the four important nutrients for WIC children, including iron, potassium, and fiber. SNAP only has a small and negative effect on fiber intake. The additional benefit of SNAP participation is non-existent given participation in WIC. © 2010 Elsevier Ltd.

Matzke N.J.,University of California at Berkeley | Matzke N.J.,University of Tennessee at Knoxville
Systematic Biology | Year: 2014

Founder-event speciation, where a rare jump dispersal event founds a new genetically isolated lineage, has long been considered crucial by many historical biogeographers, but its importance is disputed within the vicariance school. Probabilistic modeling of geographic range evolution creates the potential to test different biogeographical models against data using standard statistical model choice procedures, as long as multiple models are available. I re-implement the Dispersal-Extinction-Cladogenesis (DEC) model of LAGRANGE in the R package BioGeoBEARS, and modify it to create a new model, DEC+J, which adds founder-event speciation, the importance of which is governed by a new free parameter, j. The identifiability of DEC and DEC+J is tested on data sets simulated under a wide range of macroevolutionary models where geography evolves jointly with lineage birth/death events. The results confirm that DEC and DEC+J are identifiable even though these models ignore the fact that molecular phylogenies are missing many cladogenesis and extinction events. The simulations also indicate that DEC will have substantially increased errors in ancestral range estimation and parameter inference when the true model includes +J. DEC and DEC+J are compared on 13 empirical data sets drawn from studies of island clades. Likelihood-ratio tests indicate that all clades reject DEC, and AICc modelweights show large to overwhelming support for DEC+J, for the first time verifying the importance of founder-event speciation in island clades via statistical model choice. Under DEC+J, ancestral nodes are usually estimated to have ranges occupying only one island, rather than the widespread ancestors often favored by DEC. These results indicate that the assumptions of historical biogeography models can have large impacts on inference and require testing and comparison with statistical methods. [BioGeoBEARS; cladogenesis; extinction; founder-event speciation; GeoSSE; historical biogeography; jump dispersal; LAGRANGE.] © The Author(s) 2014. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved.

Khatabi B.,University of Tennessee at Knoxville
Plant signaling & behavior | Year: 2012

Ethylene (ET) is a gaseous phytohormone that participates in various plant physiological processes and essentially contributes to plant immunity. ET conducts its functions by regulating the expression of ET-responsive genes or in crosstalk with other hormones. Several recent studies have shown the significance of ET in the establishment and development of plant-microbe interactions. Therefore, it is not surprising that pathogens and mutualistic symbionts target ET synthesis or signaling to colonize plants. This review introduces the significance of ET metabolism in plant-microbe interactions, with an emphasis on its role in mutualistic symbioses.

Nagarsheth K.,University of Tennessee at Knoxville | Kurek S.,University of Tennessee at Knoxville
American Surgeon | Year: 2011

Pneumothorax after trauma can be a life threatening injury and its care requires expeditious and accurate diagnosis and possible intervention. We performed a prospective, single blinded study with convenience sampling at a Level I trauma center comparing thoracic ultrasound with chest X-ray and CT scan in the detection of traumatic pneumothorax. Trauma patients that received a thoracic ultrasound, chest X-ray, and chest CTscan were included in the study. The chest X-rays were read by a radiologist who was blinded to the thoracic ultrasound results. Then both were compared with CT scan results. One hundred and twenty-five patients had a thoracic ultrasound performed in the 24-month period. Forty-six patients were excluded from the study due to lack of either a chest X-ray or chest CT scan. Of the remaining 79 patients there were 22 positive pneumothorax found by CTand of those 18 (82%) were found on ultrasound and 7 (32%) were found on chest X-ray. The sensitivity of thoracic ultrasound was found to be 81.8 per cent and the specificity was found to be 100 per cent. The sensitivity of chest X-ray was found to be 31.8 per cent and again the specificity was found to be 100 per cent. The negative predictive value of thoracic ultrasound for pneumothorax was 0.934 and the negative predictive value for chest X-ray for pneumothorax was found to be 0.792. We advocate the use of chest ultrasound for detection of pneumothorax in trauma patients.

Sumrall C.D.,University of Tennessee at Knoxville
Journal of Paleontology | Year: 2010

A large, edrioasteroid-bearing hardground surface from the base of the Bellevue Member of the Grant Lake Formation near Maysville, Mason County, Kentucky is described. Four species are represented including Streptaster vorticellatus (Hall), Carneyella ulrichi Bassler and Shideler, Carneyella pilea (Hall), and Curvitriordo stecki n. sp. Specimens of S. vorticellatus and C. pilea add little to the known morphologies of these species. However, prior to this study C. ulrichi was known from the unique holotype, and Curvitriordo stecki n. sp. adds greatly to out understanding of Curvitriordo which was previously known from two species comprising three poorly preserved specimens. Curvitriordo stecki shows a bimodal size frequency distribution suggesting seasonal breeding whereas Carneyella ulrichi shows a left skewed size frequency suggesting low juvenile mortality. Streptaster vorticellatus shows a tight unimodal size frequency distribution suggestive of a single spat fall accumulation. © 2010 The Paleontological Society.

Hatcher Jr. R.D.,University of Tennessee at Knoxville
Memoir of the Geological Society of America | Year: 2010

The Appalachians are a Paleozoic orogen that formed in a complete Wilson cycle along the eastern Laurentian margin following the breakup of super continent Rodinia and the coalescence of all of the continents to form super continent Pangea. The Appalachian Wilson cycle began by formation of a Neoproterozoic to early Paleozoic rifted margin and plat form succession on the south eastern margin of Laurentia. Three orogenies ultimately producedthe mountain chain: the Ordovician Taconic orogeny , which involved arc accretion; the Acadian-Neoacadian orogeny, which involved north-to-south, transpressional, zippered, Late Devonian-early Mississippian collision of the Carolina superterrane in the southern-central Appalachians and the Avalon-Gander superterrane in the New England Appalachians, and Silurian collision in the Maritime Appalachians and Newfoundland; and the Alleghanian orogeny, which involved late Mississippian to Permian collision of all previously formed Appalachian components with Gondwana to form super continent Pangea. The Alleghanian alsoinvolved zippered, north-to-south, transpressional, then head-on collision. All orogenieswere diachronous. Similar time-correlative orogenies affected western and central Europe (Variscan events), eastern Europe and western Siberia (Uralian events), and southern Britain and Ireland; only the Caledonide (Grampian-Finnmarkian ; Caledonian-Scandian) events affected the rest of Britain and the Scandinavian Caledonides. These different events, coupled with the irregular rifted margin of Laurentia, produced an orogen that contains numerous contrasts and nonthroughgoing elements, but it also contains elements, such as the platform margin and peri-Gondwanan elements, that are recognizable throughout the orogen.© 2010 The Geological Society of America.

Zhu X.,University of Tennessee at Knoxville | Wilhelm W.E.,Texas A&M University
Computers and Operations Research | Year: 2012

This paper focuses on the common scenario in which the resource-constrained shortest path problem (RCSP) on an acyclic graph is a sub-problem in the context of column generation. It proposes a pseudo-polynomial time, three-stage solution approach. Stages 1 (preprocessing) and 2 (setup) are implemented one time to transform RCSP into a shortest path problem, which is solved by stage 3 (iterative solution) at each column generation iteration, each time with different arc costs. This paper analyzes certain properties related to each stage as well as algorithm complexity. Computational tests compare the performances of this method, a state-of-the-art label-setting algorithm, and CPLEX optimization software on four classes of instances, each of which involves either one or multiple resources, and show that the new method is effective. The new method outperforms the label-setting algorithm when resource limitations are tight - as can be expected in practice, and outperforms CPLEX for all tested instances. The label-setting algorithm outperforms CPLEX for all single-resource RCSP instances and almost all multiple-resource RCSP instances. © 2011 Elsevier Ltd.

Hoang K.V.,University of Tennessee at Knoxville
Frontiers in cellular and infection microbiology | Year: 2012

Antimicrobial peptides (AMPs) are critical components of host defense limiting bacterial infections at the gastrointestinal mucosal surface. Bacterial pathogens have co-evolved with host innate immunity and developed means to counteract the effect of endogenous AMPs. However, molecular mechanisms of AMP resistance in Campylobacter, an important human food-borne pathogen with poultry as a major reservoir, are still largely unknown. In this study, random transposon mutagenesis and targeted site-directed mutagenesis approaches were used to identify genetic loci contributing Campylobacter resistance to fowlicidin-1, a chicken AMP belonging to cathelicidin family. An efficient transposon mutagenesis approach (EZ::TN™ Transposome) in conjunction with a microtiter plate screening identified three mutants whose susceptibilities to fowlicidin-1 were significantly increased. Backcrossing of the transposon mutations into parent strain confirmed that the AMP-sensitive phenotype in each mutant was linked to the specific transposon insertion. Direct sequencing showed that these mutants have transposon inserted in the genes encoding two-component regulator CbrR, transporter CjaB, and putative trigger factor Tig. Genomic analysis also revealed an operon (Cj1580c-1584c) that is homologous to sapABCDF, an operon conferring resistance to AMP in other pathogens. Insertional inactivation of Cj1583c (sapB) significantly increased susceptibility of Campylobacter to fowlicidin-1. The sapB as well as tig and cjaB mutants were significantly impaired in their ability to compete with their wild-type strain 81-176 to colonize the chicken cecum. Together, this study identified four genetic loci in Campylobacter that will be useful for characterizing molecular basis of Campylobacter resistance to AMPs, a significant knowledge gap in Campylobacter pathogenesis.

Hagenauer M.H.,University of Michigan | Lee T.M.,University of Michigan | Lee T.M.,University of Tennessee at Knoxville
Hormones and Behavior | Year: 2013

This article is part of a Special Issue "Puberty and Adolescence".One of the defining characteristics of adolescence in humans is a large shift in the timing and structure of sleep. Some of these changes are easily observable at the behavioral level, such as a shift in sleep patterns from a relatively morning to a relatively evening chronotype. However, there are equally large changes in the underlying architecture of sleep, including a >. 60% decrease in slow brain wave activity, which may reflect cortical pruning. In this review we examine the developmental forces driving adolescent sleep patterns using a cross-species comparison. We find that behavioral and physiological sleep parameters change during adolescence in non-human mammalian species, ranging from primates to rodents, in a manner that is often hormone-dependent. However, the overt appearance of these changes is species-specific, with polyphasic sleepers, such as rodents, showing a phase-advance in sleep timing and consolidation of daily sleep/wake rhythms. Using the classic two-process model of sleep regulation, we demonstrate via a series of simulations that many of the species-specific characteristics of adolescent sleep patterns can be explained by a universal decrease in the build-up and dissipation of sleep pressure. Moreover, and counterintuitively, we find that these changes do not necessitate a large decrease in overall sleep need, fitting the adolescent sleep literature. We compare these results to our previous review detailing evidence for adolescent changes in the regulation of sleep by the circadian timekeeping system (. Hagenauer and Lee, 2012), and suggest that both processes may be responsible for adolescent sleep patterns. © 2013 .

Burghardt G.M.,University of Tennessee at Knoxville
Behavioral and Brain Sciences | Year: 2013

Van de Vliert proposes a comprehensive explanation for differences in freedoms in diverse human populations based on climate and monetary resources. This intriguing approach, though derived from an evolutionary view covering all species, is based exclusively on human populations. This anthropocentric lens is challenged by ways of testing Van de Vliert's thesis more generally using playfulness as a surrogate for freedom. Copyright © 2013 Cambridge University Press.

King G.M.,Louisiana State University | Kostka J.E.,Georgia Institute of Technology | Hazen T.C.,University of Tennessee at Knoxville | Sobecky P.A.,University of Alabama
Annual Review of Marine Science | Year: 2015

The Deepwater Horizon oil spill in the northern Gulf of Mexico represents the largest marine accidental oil spill in history. It is distinguished from past spills in that it occurred at the greatest depth (1,500 m), the amount of hydrocarbon gas (mostly methane) lost was equivalent to the mass of crude oil released, and dispersants were used for the first time in the deep sea in an attempt to remediate the spill. The spill is also unique in that it has been characterized with an unprecedented level of resolution using next-generation sequencing technologies, especially for the ubiquitous hydrocarbon-degrading microbial communities that appeared largely to consume the gases and to degrade a significant fraction of the petroleum. Results have shown an unexpectedly rapid response of deep-sea Gammaproteobacteria to oil and gas and documented a distinct succession correlated with the control of the oil flow and well shut-in. Similar successional events, also involving Gammaproteobacteria, have been observed in nearshore systems as well. Copyright © 2015 by Annual Reviews. All rights reserved.

Lawson C.M.,University of Tennessee at Knoxville
JPEN. Journal of parenteral and enteral nutrition | Year: 2013

Defining malnutrition and nutrition risk has been a topic of many papers and discussions throughout the modern literature. Multiple definitions have been proposed, ranging from simple body weight measurements to a more all-encompassing concept looking at disease-specific inflammatory states. Biochemical markers, elements of a history examination, physical examination findings, calculations, and technical tests have all been proposed to help further characterize and delineate those who might be at risk for malnutrition, translating to an increased risk of adverse outcomes after major surgery. The purpose of this paper is to summarize some of the most utilized and most reliable ways to determine nutrition status within the scope of the North American Surgical Nutrition Summit (2012) and discuss how to incorporate these methods into the way that patients are screened preoperatively for elective surgery.

Sheffield S.L.,University of Tennessee at Knoxville
Palaeoworld | Year: 2015

The erisocrinid Sinocrinus differs from other erisocrinid genera (Erisocrinus and Exaetocrinus) by possessing a rounded, bowl-shaped cup, bearing tumid cup plates with impressed sutures. Sinocrinus Tien, 1926 is refined using Principal Component Analysis and neighborhood cluster analysis. The genotype of Sinocrinus, S. microgranulosus Tien, 1926, is a junior subjective synonym of S. granulatus (Wanner, 1924). Sinocrinus [ Erisocrinus] stefaninii (Yakovlev, 1934) is a junior synonym of Sinocrinus lichengensis Tien, 1926 and S. asymmetricus Strimple and Watkins, 1969 is the junior synonym of S. sheareri Strimple and Watkins, 1969. Other valid species include: S. [ Erisocrinus] cernuus (Trautschold, 1867); S. [ Erisocrinus] obliquus (Wanner, 1916); S. houkouensis Tien, 1926; S. nodosus Tien, 1926; S. [ Erisocrinus] stefaninii (Yakovlev, 1934). Because of its refined inclusiveness, the temporal span of the genus now extends from the Late Carboniferous (Moscovian) through the early Permian (Sakmarion). This study also widens the current geographic range of Sinocrinus, with specimens collected across a wider span of Eurasia. © 2015 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS.

Li H.,University of Tennessee at Knoxville | Lai L.,University of Arkansas at Little Rock | Poor H.V.,Princeton University
IEEE Journal on Selected Areas in Communications | Year: 2012

In cyber physical systems, communication is needed for conveying sensor observations to controllers; thus, the design of the communication sub-system is of key importance for the stabilization of system dynamics. In this paper, multicast routing is studied for networking of decentralized sensors and controllers. The challenges of uncertain destinations and multiple routing modes, which are significantly different from traditional data networks, are addressed by employing the theories of hybrid systems and linear matrix inequalities, thus forming a novel framework for studying the communication sub-system in cyber physical systems. Both cases of neglible delay and non-negligible delay are discussed. The proposed framework is then applied in the context of voltage control in smart grid. Numerical simulations using a 4-bus power grid model show that the proposed framework and algorithm can effectively stabilize cyber physical systems. © 2012 IEEE.

Ganusov V.V.,University of Tennessee at Knoxville
Frontiers in Microbiology | Year: 2016

While there are many opinions on what mathematical modeling in biology is, in essence, modeling is a mathematical tool, like a microscope, which allows consequences to logically follow from a set of assumptions. Only when this tool is applied appropriately, as microscope is used to look at small items, it may allow to understand importance of specific mechanisms/assumptions in biological processes. Mathematical modeling can be less useful or even misleading if used inappropriately, for example, when a microscope is used to study stars. According to some philosophers (Oreskes et al., 1994), the best use of mathematical models is not when a model is used to confirm a hypothesis but rather when a model shows inconsistency of the model (defined by a specific set of assumptions) and data. Following the principle of strong inference for experimental sciences proposed by Platt (1964), I suggest "strong inference in mathematical modeling" as an effective and robust way of using mathematical modeling to understand mechanisms driving dynamics of biological systems. The major steps of strong inference in mathematical modeling are (1) to develop multiple alternative models for the phenomenon in question; (2) to compare the models with available experimental data and to determine which of the models are not consistent with the data; (3) to determine reasons why rejected models failed to explain the data, and (4) to suggest experiments which would allow to discriminate between remaining alternative models. The use of strong inference is likely to provide better robustness of predictions of mathematical models and it should be strongly encouraged in mathematical modeling-based publications in the Twenty-First century. © 2016 Ganusov.

Gavrilets S.,University of Tennessee at Knoxville
Cold Spring Harbor Perspectives in Biology | Year: 2014

At the end of the last century, sexual conflict was identified as a powerful engine of speciation, potentially even more important than ecological selection. Earlier work that followed-experimental, comparative, and mathematical—provided strong initial support for this assertion. However, as the field matures, both the power of sexual conflict and constraints on the evolution of reproductive isolation as driven by sexual conflict are becoming better understood. From theoretical studies, we now know that speciation is only one of several possible evolutionary outcomes of sexual conflict. In line with these predictions, both experimental evolution studies and comparative analyses of fertilization proteins and of species richness show that sexual conflict leads to, or is associated with, reproductive isolation and speciation in some cases but not in others. Increased genetic variation (especially in females) without reproductive isolation is an underappreciated consequence of sexually antagonistic selection. © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

Demkowicz M.J.,Massachusetts Institute of Technology | Bellon P.,Urbana University | Wirth B.D.,University of Tennessee at Knoxville
MRS Bulletin | Year: 2010

Recent work Indicates that materials with nanoscale architectures, such as nanolayered Cu-Nb composites and nanoscale oxide dispersion-strengthened steels, are both thermally stable and offer improved performance under irradiation. Current understanding of the atomiclevel response of such materials to radiation yields insights into how controlling composition, morphology, and interface-defect interactions may further enable atomic-scale design of radiation-tolerant nanostructured composite materials. With greater understanding of irradiation-assisted degradation mechanisms, this bottom-up design approach may pave the way for creating the extreme environment - tolerant structural materials needed to meet the world's clean energy demand by expanding use of advanced fission and future fusion power.

Litz J.P.,University of Washington | Camden J.P.,University of Tennessee at Knoxville | Masiello D.J.,University of Washington
Journal of Physical Chemistry Letters | Year: 2011

The electromagnetic scattering properties of Ag nanoparticle aggregates known to be antennas for single-molecule surface-enhanced Raman scattering are investigated from a continuum electrodynamics perspective. High-resolution mappings of the spatial, spectral, and polarization dependence of the volumes of the aggregate's electromagnetic hot spots reveal multiple active regions for enhanced Raman scattering activity by molecular chromophores. Further analysis of these regions using maps of polarization surface-charge density shows that some hot spots are due to the collective and phase-coherent excitation of localized surface-plasmon resonances, whereas others derive from interfering plasmonic excitations resulting from scattering from gaps and surfaces. The latter are still capable of generating intense local fields at certain excitation energies, whereas the former tend to provide the most spatially delocalized regions of high electromagnetic-field strength. © 2011 American Chemical Society.

Lu Z.,University of Tennessee at Knoxville | Alan Cramer S.A.,University of Tennessee at Knoxville | Jenkins D.M.,University of Tennessee at Knoxville
Chemical Science | Year: 2012

A dimeric macrocyclic tetra-N-heterocyclic carbene (NHC) silver complex was synthesized and shown to successfully extend transmetallation of polydentate NHCs beyond bidentate NHCs. The silver complex was utilized in the preparation of a variety of monomeric tetra-NHC complexes ranging from early first row to late third row transition metals in moderate to high yield for a total of nine examples of transmetallation. Among these complexes are rare examples of silver transmetallation with first row transition metals: chromium, iron, and cobalt. Additionally, the first examples of tetracarbenes on chromium and gold are reported. All compounds were characterized by single crystal X-ray diffraction, ESI-MS, and spectroscopic techniques. © 2012 The Royal Society of Chemistry.

Smith S.A.,University of Michigan | O'Meara B.C.,University of Tennessee at Knoxville
Bioinformatics | Year: 2012

Ever larger phylogenies are being constructed due to the explosion of genetic data and development of high-performance phylogenetic reconstruction algorithms. However, most methods for calculating divergence times are limited to datasets that are orders of magnitude smaller than recently published large phylogenies. Here, we present an algorithm and implementation of a divergence time method using penalized likelihood that can handle datasets of thousands of taxa. We implement a method that combines the standard derivative-based optimization with a stochastic simulated annealing approach to overcome optimization challenges. We compare this approach with existing software including r8s, PATHd8 and BEAST. © The Author 2012. Published by Oxford University Press. All rights reserved.

Morrison K.E.,University of Tennessee at Knoxville | Cooper M.A.,University of Tennessee at Knoxville
Pharmacology Biochemistry and Behavior | Year: 2012

The basolateral nucleus of the amygdala (BLA) is a key brain region regulating behavioral changes following stressful events, including social defeat. Previous research has shown that activation of serotonin (5-HT) 1A receptors in the BLA reduces conditioned fear and anxiety-like behavior. The objective of this study was to test whether 5-HT1A receptors in the BLA contribute to conditioned defeat in male Syrian hamsters (Mesocricetus auratus). We tested whether injection of the selective 5-HT1A receptor agonist flesinoxan (400 ng, 800 ng, or 1200 ng in 200 nl saline) into the BLA prior to social defeat would reduce the acquisition of conditioned defeat, and whether a similar injection prior to testing would reduce the expression of conditioned defeat. We also tested whether injection of the selective 5-HT1A receptor antagonist WAY-100635 (400 ng or 1600 ng in 200 nl saline) into the BLA prior to social defeat would enhance the acquisition of conditioned defeat, and whether a similar injection prior to testing would enhance the expression of conditioned defeat. We found that injection of flesinoxan into the BLA decreased both the acquisition and expression of conditioned defeat. However, injection of WAY-100635 into the BLA did not alter the acquisition or expression of conditioned defeat. These data indicate that pharmacological activation of 5-HT1A receptors in the BLA is sufficient to impair the acquisition and expression of conditioned defeat. Our results suggest that pharmacological treatments that activate 5-HT1A receptors in the BLA are capable of reducing the development of stress-induced changes in behavior. © 2011 Elsevier Inc. All rights reserved.

Cude W.N.,University of Tennessee at Knoxville | Buchan A.,University of Tennessee at Knoxville
Frontiers in Microbiology | Year: 2013

Bacteria have been widely reported to use quorum sensing (QS) systems, which employ small diffusible metabolites to coordinate gene expression in a population density dependent manner. In Proteobacteria, the most commonly described QS signaling molecules are N-acyl-homoserine lactones (AHLs). Recent studies suggest that members of the abundant marine Roseobacter lineage possess AHL-based QS systems and are environmentally relevant models for relating QS to ecological success. As reviewed here, these studies suggest that the roles of QS in roseobacters are varied and complex. An analysis of the 43 publically available Roseobacter genomes shows conservation of QS protein sequences and overall gene topologies, providing support for the hypothesis that QS is a conserved and widespread trait in the clade. © 2013 Cude and Buchan.

Harden C.P.,University of Tennessee at Knoxville
Geomorphology | Year: 2013

Field research enables a researcher to view geomorphic systems in broader contexts than those envisioned while at a desk and can yield unanticipated insights that change the course of an investigation or affect the interpretation of results. Geomorphological field research often produces 'aha!' moments, epiphanies that enhance understanding and lead toward more complete explanation of the processes and landforms under study. This paper uses examples from 'aha!' moments in the field to demonstrate the importance of field observation as a way of gaining information about the broader contexts of research sites, especially in process geomorphology. Spatial contexts include the scales of processes and features, linkages between a study site and its surroundings, and information observed in the field about other processes, anthropogenic activities, or unexpected factors that might affect a study. Temporal contexts, not as evident in the field, place a research site in a longer term history of changes and adjustments. Finally, exploring an abstract set of mental contexts reveals reasons that expectations differ from the realities encountered in the field-constraints and biases that a researcher may not have noted-and the possibility that the unexpected can potentially advance geomorphic research. Time spent in the field complements scientific reductionism and provides opportunities to appreciate the richness and complexity of Earth surface systems. © 2013 Elsevier B.V.

Wen J.,University of Tennessee at Knoxville | Won D.,University of Tennessee at Knoxville | Fozo E.M.,University of Tennessee at Knoxville
Nucleic Acids Research | Year: 2014

Type I toxin-Antitoxin loci consist of two genes: a small, hydrophobic, potentially toxic protein, and a small RNA (sRNA) antitoxin. The sRNA represses toxin gene expression by base pairing to the toxin mRNA. A previous bioinformatics search predicted a duplicated type I locus within Escherichia coli O157:H7 (EHEC), which we have named the gene pairs zorO-orzO and zorP-orzP. We show that overproduction of the zorO gene is toxic to E. coli; co-expression of the sRNA OrzO can neutralize this toxicity, confirming that the zorO-orzO pair is a true type I toxin-Antitoxin locus. However, OrzO is unable to repress zorO in a strain deleted for RNase III, indicating that repression requires cleavage of the target mRNA. Sequence analysis and mutagenesis studies have elucidated a nucleotide sequence region (V1) that allows differential recognition of the zorO mRNA by OrzO and not OrzP, and a specific single nucleotide within the V1 of OrzO that is critical for repression of zorO. Although there are 18 nt of complementarity between the OrzO sRNA and the zorO mRNA, not all base pairing interactions are needed for repression; however, the amount needed is dependent on whether there is continuous or discontinuous complementarity to the target mRNA. © 2013 The Author(s) 2013. Published by Oxford University Press.

Truster T.J.,University of Tennessee at Knoxville
Engineering Fracture Mechanics | Year: 2016

An algorithm is summarized for inserting zero-thickness interface elements or "couplers" into finite element meshes in two and three dimensions. Using only element connectivity, couplers are inserted according to regions within the analysis domain, a geometrically intuitive means to designate their locations. A wide class of volume elements and interface couplers are treated. A three-dimensional test case verifies that the algorithm generates meshes passing the patch test. © 2015 Elsevier Ltd.

Jiang X.,University of Tennessee at Knoxville
Traffic injury prevention | Year: 2013

Previous studies of pavement management factors that relate to the occurrence of traffic-related crashes are rare. Traditional research has mostly employed summary statistics of bidirectional pavement quality measurements in extended longitudinal road segments over a long time period, which may cause a loss of important information and result in biased parameter estimates. The research presented in this article focuses on crash risk of roadways with overall fair to good pavement quality. Real-time and location-specific data were employed to estimate the effects of pavement management factors on the occurrence of crashes. This research is based on the crash data and corresponding pavement quality data for the Tennessee state route highways from 2004 to 2009. The potential temporal and spatial correlations among observations caused by unobserved factors were considered. Overall 6 models were built accounting for no correlation, temporal correlation only, and both the temporal and spatial correlations. These models included Poisson, negative binomial (NB), one random effect Poisson and negative binomial (OREP, ORENB), and two random effect Poisson and negative binomial (TREP, TRENB) models. The Bayesian method was employed to construct these models. The inference is based on the posterior distribution from the Markov chain Monte Carlo (MCMC) simulation. These models were compared using the deviance information criterion. Analysis of the posterior distribution of parameter coefficients indicates that the pavement management factors indexed by Present Serviceability Index (PSI) and Pavement Distress Index (PDI) had significant impacts on the occurrence of crashes, whereas the variable rutting depth was not significant. Among other factors, lane width, median width, type of terrain, and posted speed limit were significant in affecting crash frequency. The findings of this study indicate that a reduction in pavement roughness would reduce the likelihood of traffic-related crashes. Hence, maintaining a low level of pavement roughness is strongly suggested. In addition, the results suggested that the temporal correlation among observations was significant and that the ORENB model outperformed all other models.

Lennox G.D.,University of Sheffield | Armsworth P.R.,University of Tennessee at Knoxville
Conservation Biology | Year: 2013

In negotiations over land-right acquisitions, landowners have an informational advantage over conservation groups because they know more about the opportunity costs of conservation measures on their sites. This advantage creates the possibility that landowners will demand payments greater than the required minimum, where this minimum required payment is known as the landowner's willingness to accept (WTA). However, in recent studies of conservation costs, researchers have assumed landowners will accept conservation with minimum payments. We investigated the ability of landowners to demand payments above their WTA when a conservation group has identified multiple sites for protection. First, we estimated the maximum payment landowners could potentially demand, which is set when groups of landowners act as a cooperative. Next, through the simulation of conservation auctions, we explored the amount of money above landowners' WTA (i.e., surplus) that conservation groups could cede to secure conservation agreements, again investigating the influence of landowner cooperatives. The simulations showed the informational advantage landowners held could make conservation investments up to 42% more expensive than suggested by the site WTAs. Moreover, all auctions resulted in landowners obtaining payments greater than their WTA; thus, it may be unrealistic to assume landowners will accept conservation contracts with minimum payments. Of particular significance for species conservation, conservation objectives focused on overall species richness, which therefore recognize site complementarity, create an incentive for landowners to form cooperatives to capture surplus. To the contrary, objectives in which sites are substitutes, such as the maximization of species occurrences, create a disincentive for cooperative formation. © 2013 Society for Conservation Biology.

Corrinoid auxotrophic organohalide-respiring Dehalococcoides mccartyi (Dhc) strains are keystone bacteria for reductive dechlorination of toxic and carcinogenic chloroorganic contaminants. We demonstrate that the lower base attached to the essential corrinoid cofactor of reductive dehalogenase (RDase) enzyme systems modulates dechlorination activity and affects the vinyl chloride (VC) RDases BvcA and VcrA differently. Amendment of 5,6-dimethylbenzimidazolyl-cobamide (DMB-Cba) to Dhc strain BAV1 and strain GT cultures supported cis-1,2-dichloroethene-to-ethene reductive dechlorination at rates of 107.0 (±12.0) μM and 67.4 (±1.4) μM Cl- released per day, respectively. Strain BAV1, expressing the BvcA RDase, reductively dechlorinated VC to ethene, although at up to fivefold lower rates in cultures amended with cobamides carrying 5-methylbenzimidazole (5-MeBza), 5-methoxybenzimidazole (5-OMeBza) or benzimidazole (Bza) as the lower base. In contrast, strain GT harboring the VcrA RDase failed to grow and dechlorinate VC to ethene in medium amended with 5-OMeBza-Cba or Bza-Cba. The amendment with DMB to inactive strain GT cultures restored the VC-to-ethene-dechlorinating phenotype and intracellular DMB-Cba was produced, demonstrating cobamide uptake and remodeling. The distinct responses of Dhc strains with BvcA versus VcrA RDases to different cobamides implicate that the lower base exerts control over Dhc reductive dechlorination rates and extents (that is, detoxification), and therefore the dynamics of Dhc strains with discrete reductive dechlorination capabilities. These findings emphasize that the role of the corrinoid/lower base synthesizing community must be understood to predict strain-specific Dhc activity and achieve efficacious contaminated site cleanup.The ISME Journal advance online publication, 10 November 2015; doi:10.1038/ismej.2015.197. © 2015 International Society for Microbial Ecology

Bui H.N.,University of Tennessee at Knoxville
Journal of Immigrant and Minority Health | Year: 2013

Using data from the National Longitudinal Studies of Adolescent Health, the present study examines self-reported substance use (cigarettes, tobacco, and marijuana) among youth from different immigration generations to determine the immigrant paradox in substance use for different racial and ethnic groups as well as factors contributing to the relationship between immigration and substance use. Results of data analysis indicate the immigrant paradox in substance use among non-Hispanic Whites, Asians, and Hispanics, but not among non-Hispanic Blacks. The study also shows that factors explaining the immigrant paradox in substance use vary with racial and ethnic groups, but English use at home, friends' cigarette and marijuana use appear to be the most important mediating factors. Findings from the study suggest that effective interventions in youth substance use require an understanding of adaptation patterns in different racial and ethnic groups, so that factors associated with adaptation problems experienced by particular groups will be appropriately addressed. © 2012 Springer Science+Business Media, LLC.

Schwartz F.,University of Tennessee at Knoxville
Annales Henri Poincare | Year: 2011

We consider asymptotically flat Riemannian manifolds with non-negative scalar curvature that are conformal to ℝ n\Ω, n ≥ 3, and so that their boundary is a minimal hypersurface. (Here, Ω ⊂ ℝ n is open bounded with smooth mean-convex boundary.) We prove that the ADM mass of any such manifold is bounded below by 1/2(V/β n) (n-2)/n, where V is the Euclidean volume of Ω and β n is the volume of the Euclidean unit n-ball. This gives a partial proof to a conjecture of Bray and Iga (Commun. Anal. Geom. 10:999-1016, 2002). Surprisingly, we do not require the boundary to be outermost. © 2010 Springer Basel AG.

Egami T.,University of Tennessee at Knoxville | Egami T.,Oak Ridge National Laboratory
Journal of Alloys and Compounds | Year: 2011

The current majority view on the phenomenon of mechanical failure in metallic glasses appears to be that it is caused by the activity of some structural defects, such as free-volumes or shear transformation zones, and the concentration of such defects is small, only of the order of 1%. However, the recent results compel us to revise this view. Through molecular dynamics simulation it has been shown that mechanical failure is the stress-induced glass transition. According to our theory the concentration of the liquid-like sites (defects) is well over 20% at the glass transition. We suggest that the defect concentration in metallic glasses is actually very high, and percolation of such defects causes atomic avalanche and mechanical failure. In this article we discuss the glass transition, mechanical failure and viscosity from such a point of view. © 2010 Elsevier B.V. All rights reserved.

Egami T.,University of Tennessee at Knoxville | Egami T.,Oak Ridge National Laboratory
Progress in Materials Science | Year: 2011

The birth and subsequent development of the concept of the atomic level stresses are reviewed, and its future is discussed. Initially it was conceived as a means of describing the local structure in metallic glasses. It gradually became evident that its capacity is beyond the initial expectation. It appears that this concept is a powerful tool in understanding diverse phenomena in strongly disordered systems, such as the atomic dynamics in liquids, glass transition, mechanical failure and structural relaxation. This concept also has a potential to bridge distinct fields of glass research beyond metallic glasses, including colloids, molecular liquids, granular matter and other materials. © 2011 Elsevier Ltd. All rights reserved.

Wunderlich B.,University of Tennessee at Knoxville
Journal of Thermal Analysis and Calorimetry | Year: 2011

The first measurements in our laboratory of some 55 years ago dealt with adiabatic calorimetry of linear, semicrystalline polyethylene. Quickly it became obvious that time needed to be controlled to study the metastable and unstable states. Shortly thereafter, my first students were building our own DTA, capable to give quantitative, time-dependent calorimetric data. Only few years later, we could present the quantitative link between molecular motion and heat capacity in the melting and glass-transition regions. One of these students involved in this study was Prof. Michael Jaffe. His study dealt with semicrystalline polyoxymethylene, a synthetic carbohydrate. He could use the first quantitative commercial equipment and modify it to heating with rates of 100 K min -1 and more. Today, rates reaching up to 10 7 K min -1 and faster are available for the analysis of unstable and small phases. The key question of this beginning study on biopolymer-related materials is the title question of this presentation for this symposium. © 2011 Akadémiai Kiadó, Budapest, Hungary.

Truster T.J.,University of Tennessee at Knoxville
Computational Mechanics | Year: 2016

A heterogeneous interface method is developed for combining primal displacement and mixed displacement-pressure formulations across nonconforming finite element meshes to treat volume-preserving plastic flow. When the zone of inelastic response is localized within a larger domain, significant computational savings can be achieved by confining the mixed formulation solely to the localized region. The method’s distinguishing feature is that the coupling terms for joining dissimilar element types are derived from a time-discrete free energy functional, which is based on a Lagrange multiplier formulation of the interface constraints. Incorporating residual-based stabilizing terms at the interface enables the condensation of the multiplier field, leading to a symmetric Nitsche formulation in which the interface operators respect the differing character of the governing equations in each region. In a series of numerical problems, the heterogeneous interface method achieved comparable results on coarser meshes as those obtained from applying the mixed formulation throughout the domain. © 2015, Springer-Verlag Berlin Heidelberg.

Sehrawat S.,University of Tennessee at Knoxville
PLoS pathogens | Year: 2010

In this communication, we demonstrate that galectin (Gal)-9 acts to constrain CD8(+) T cell immunity to Herpes Simplex Virus (HSV) infection. In support of this, we show that animals unable to produce Gal-9, because of gene knockout, develop acute and memory responses to HSV that are of greater magnitude and better quality than those that occur in normal infected animals. Interestingly, infusion of normal infected mice with alpha-lactose, the sugar that binds to the carbohydrate-binding domain of Gal-9 limiting its engagement of T cell immunoglobulin and mucin (TIM-3) receptors, also caused a more elevated and higher quality CD8(+) T cell response to HSV particularly in the acute phase. Such sugar treated infected mice also had expanded populations of effector as well as memory CD8(+) T cells. The increased effector T cell responses led to significantly more efficient virus control. The mechanisms responsible for the outcome of the Gal-9/TIM-3 interaction in normal infected mice involved direct inhibitory effects on TIM-3(+) CD8(+) T effector cells as well as the promotion of Foxp3(+) regulatory T cell activity. Our results indicate that manipulating galectin signals, as can be achieved using appropriate sugars, may represent a convenient and inexpensive approach to enhance acute and memory responses to a virus infection.

Riechert S.E.,University of Tennessee at Knoxville
Animal Behaviour | Year: 2013

Maynard Smith & Parker (1976, Animal Behaviour, 24, 159-175) offered animal behaviourists and behavioural ecologists a theoretical framework/guide to understanding animal behaviour in competitive contexts. In this essay I trace the influence of this 'contest rule book' from the factors that led the two researchers to develop a treatise on the logic of the asymmetric game to empirical tests of the contest rules and theoretical additions made to the basic model and its underlying assumptions. Over a thousand studies cite this paper directly and thousands more cite work spurred by the original paper. The vast majority of these studies confirm the evolutionarily stable strategy (ESS) predictions made by Maynard Smith & Parker. Theoretical and empirical deviations from EES can largely be explained by the need for further structuring of the analyses into subgames and investigation of less obvious asymmetries than apparent size and resource value. To date, much progress has been made in three areas of interest to behaviourists: (1) understanding of the strategic nature of contests between conspecifics over limited resources; (2) modelling developments that deal with how information about potential asymmetries is gained; and (3) evaluation of the question of honest signalling with specific reference to threat displays. Here, I propose suggestions for future work, much of which will either require collaboration with mathematicians, or require that students interested in animal behaviour obtain a strong foundation in biomathematics. My preference is for the latter strategy. © 2013.

Warren R.J.,State University of New York at Buffalo | Chick L.,University of Tennessee at Knoxville
Global Change Biology | Year: 2013

Rapid climate change may prompt species distribution shifts upward and poleward, but species movement in itself is not sufficient to establish climate causation. Other dynamics, such as disturbance history, may prompt species distribution shifts resembling those expected from rapid climate change. Links between species distributions, regional climate trends and physiological mechanism are needed to convincingly establish climate-induced species shifts. We examine a 38-year shift (1974-2012) in an elevation ecotone between two closely related ant species, Aphaenogaster picea and A. rudis. Even though A. picea and A. rudis are closely related with North American distributions that sometimes overlap, they also exhibit local- and regional-scale differences in temperature requirements so that A. rudis is more southerly and inhabits lower elevations whereas A. picea is more northerly and inhabits high elevations. We find considerable movement by the warm-habitat species upward in elevation between 1974 and 2012 with A. rudis, replacing the cold-habitat species, A. picea, along the southern edge of the Appalachian Mountain chain in north Georgia, USA. Concomitant with the distribution shifts, regional mean and maximum temperatures remain steady (1974-2012), but minimum temperatures increase. We collect individuals from the study sites and subject them to thermal tolerance testing in a controlled setting and find that maximum and minimum temperature acclimatization occurs along the elevation gradient in both species, but A. rudis consistently becomes physiologically incapacitated at minimum and maximum temperatures 2 °C higher than A. picea. These results indicate that rising minimum temperatures allow A. rudis to move upward in elevation and displace A. picea. Given that Aphaenogaster ants are the dominant woodland seed dispersers in eastern deciduous forests, and that their thermal tolerances drive distinct differences in temperature-cued synchrony with early blooming plants, these climate responses not only impact ant-ant interactions, but might have wide implications for ant-plant interactions. © 2013 Blackwell Publishing Ltd.

Elder T.,U.S. Department of Agriculture | Beste A.,University of Tennessee at Knoxville
Energy and Fuels | Year: 2014

Studies on the pyrolysis mechanisms of lignin model compounds have largely focused on initial homolytic cleavage reactions. It has been noted, however, that concerted mechanisms may also account for observed product formation. In the current work, the latter processes are examined and compared to the former, by the application of density functional theory calculations to fully substituted lignin models. Results show that activation energies for the concerted reactions are somewhat lower than the bond dissociation energies of the homolysis reactions. Kinetic analysis revealed that the concerted pathway is the retro-ene fragmentation mechanism. © 2014 American Chemical Society.

Felker-Quinn E.,University of Tennessee at Knoxville | Bailey J.K.,University of Tennessee at Knoxville | Schweitzer J.A.,University of Tennessee at Knoxville
Ecology | Year: 2011

Invasive plant species alter soils in ways that may affect the success of subsequent generations, creating plant-soil feedbacks. Ailanthus altissima is an invasive tree introduced two centuries ago to North America. We hypothesized that geographically distinct populations of A. altissima have established feedbacks specific to their local environment, due to soil communities cultivated by A. altissima. We collected seeds and soils from three populations in the eastern United States, and in the greenhouse reciprocally planted all families in all collected soils as well as in a control mixed soil, and in soils that had been irradiated for sterilization. There were positive plant-soil feedbacks for two populations in the live field-collected soils, but strong negative feedbacks for the third population. There were no population-level performance differences or feedbacks in the sterilized population locale soils, supporting a soil biotic basis for feedbacks and for the expression of genetic differentiation in A. altissima. If populations of Ailanthus altissima vary in the extent to which they benefit from and promote these plant-soil biota feedbacks, the interaction between invader and invaded community may be more important in determining the course of invasion than are the characteristics of either alone. © 2011 by the Ecological Society of America.

Thibert-Plante X.,McGill University | Thibert-Plante X.,University of Tennessee at Knoxville | Hendry A.P.,McGill University
Journal of Evolutionary Biology | Year: 2011

Many factors could influence progress towards sympatric speciation. Some of the potentially important ones include competition, mate choice and the degree to which alternative sympatric environments (resources) are discrete. What is not well understood is the relative importance of these different factors, as well as interactions among them. We use an individual-based numerical model to investigate the possibilities. Mate choice was modelled as the degree to which male foraging traits influence female mate choice. Competition was modelled as the degree to which individuals with different phenotypes compete for portions of the resource distribution. Discreteness of the environment was modelled as the degree of bimodality of the underlying resource distribution. We find that strong mate choice was necessary, but not sufficient, to cause sympatric speciation. In addition, sympatric speciation was most likely when the resource distribution was strongly bimodal and when competition among different phenotypes was intermediate. Even under these ideal conditions, however, sympatric speciation occurred only a fraction of the time. Sympatric speciation owing to competition on unimodal resource distributions was also possible, but much less common. In all cases, stochasticity played an important role in determining progress towards sympatric speciation, as evidenced by variation in outcomes among replicate simulations for a given set of parameter values. Overall, we conclude that the nature of competition is much less important for sympatric speciation than is the nature of mate choice and the underlying resource distribution. We argue that an increased understanding of the promoters and inhibitors of sympatric speciation is best achieved through models that simultaneously evaluate multiple potential factors. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

Horm K.M.,University of Tennessee at Knoxville | D'Souza D.H.,University of Tennessee at Knoxville
Food Microbiology | Year: 2011

Fresh fruits, juices, and beverages have been implicated in human noroviral and hepatitis A virus outbreaks. The purpose of this study was to determine the survival of human norovirus surrogates (murine norovirus, MNV-1; feline calicivirus, FCV-F9; and bacteriophage MS2) in juices (orange and pomegranate juices), juice blends (pomegranate and orange juice) and milk over 0, 1, 2, 7, 14, and 21 days at refrigeration (4 °C). Juices, juice blends, and milk were inoculated with each virus over 21 days, serially diluted in cell culture media, and plaque assayed. MNV-1 showed no reduction in titer after 21 days in orange juice and milk, but moderate reduction (1.4 log) in pomegranate juice from a titer of 5 log10 PFU/ml. However, MNV-1 was completely reduced after 7 days in the orange and pomegranate juice blend. FCV-F9 from a titer of 6 log10 PFU/ml was completely reduced after 14 days in orange as well as pomegranate juice and by ∼3 logs after 21 days in milk at 4 °C. Interestingly, FCV-F9 was completely reduced after 1 day in the orange and pomegranate juice blend at 4 °C. MS2 was reduced by ∼1.28 log after 21 days in orange juice from a titer of 6 log10 PFU/ml, and <1 log after 21 days in milk or pomegranate juice, with juice blends showing minimal reduction (<1 log) after 21 days at 4 °C. These results show the survival pattern of noroviruses that aid in the transmission of foodborne viral outbreaks. The data obtained can be used in quantitative viral risk assessment studies and to develop improved measures to prevent virus survival towards controlling outbreaks. © 2011.

Williams N.J.,University of Tennessee at Knoxville | Glisson C.,University of Tennessee at Knoxville
Child Abuse and Neglect | Year: 2014

Theories of organizational culture and climate (OCC) applied to child welfare systems hypothesize that strategic dimensions of organizational culture influence organizational climate and that OCC explains system variance in youth outcomes. This study provides the first structural test of the direct and indirect effects of culture and climate on youth outcomes in a national sample of child welfare systems and isolates specific culture and climate dimensions most associated with youth outcomes. The study applies multilevel path analysis (ML-PA) to a U.S. nationwide sample of 2,380 youth in 73 child welfare systems participating in the second National Survey of Child and Adolescent Well-being. Youths were selected in a national, two-stage, stratified random sample design. Youths' psychosocial functioning was assessed by caregivers' responses to the Child Behavior Checklist at intake and at 18-month follow-up. OCC was assessed by front-line caseworkers' (N= 1,740) aggregated responses to the Organizational Social Context measure. Comparison of the a priori and subsequent trimmed models confirmed a reduced model that excluded rigid organizational culture and explained 70% of the system variance in youth outcomes. Controlling for youth- and system-level covariates, systems with more proficient and less resistant organizational cultures exhibited more functional, more engaged, and less stressful climates. Systems with more proficient cultures and more engaged, more functional, and more stressful climates exhibited superior youth outcomes. Findings suggest child welfare administrators can support service effectiveness with interventions that improve specific dimensions of culture and climate. © 2013 Elsevier Ltd.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Journal of Chromatography A | Year: 2010

The reduced heights equivalent to a theoretical plate (HETP) of naphtho[2,3-a]pyrene were measured at room temperature on two sets of new prototype columns designed to be used in very high pressure liquid chromatography (VHPLC). The mobile phase used was pure acetonitrile. The columns are 50, 100, and 150 mm long. Those of the first set are 2.1 mm I.D., those of the second set, 3.0 mm I.D. The performance of these new columns were compared to those of the first generation of VHPLC columns, commercially available in 2.1 mm I.D. The prototype and commercial columns behave similarly at low reduced linear velocities (ν < 5), when the heat effects are negligible. At high flow rates, the shorter prototype columns have a twice better efficiency and less steep C-branches than the commercial columns. In contrast, the C-branch of the 150 mm long prototype columns are slightly steeper than those of the commercial columns. The important contribution to the reduced HETP that is due to the heat effects at high flow rates can in part be accounted for by a band broadening model governed by a flow mechanism with the shortest prototype columns. The sole heat effects cannot, however, explain the mediocre reduced HETPs of the 2.1 and 3.0 I.D. 150 mm long prototype columns. It seems that radial heterogeneity of the flow rate of the long prototype columns is significantly larger than that of the short columns. The contribution of the packing heterogeneity adds up to that of the heat effects to yield a poor column efficiency when sub- 2 μ m are packed into thin, long column tubes. © 2009 Elsevier B.V. All rights reserved.

Habenicht B.F.,University of Tennessee at Knoxville | Paddison S.J.,University of Tennessee at Knoxville
Journal of Physical Chemistry B | Year: 2011

Carbon nanotubes (CNTs) were functionalized with -CF2SO 3H groups and hydrated with 1-3 water molecules per sulfonic acid group to investigate proton dissociation and transport in confined, hydrophobic environments. The distance between sulfonate groups was systematically varied from 6 to 8 Å, and three different CNTs were used to determine the effects of nanoscale confinement. The inner walls of the CNT were either functionalized with fluorine atoms to provide a localized negative charge or left bare to provide a more delocalized charge distribution. The use of ab initio molecular dynamics permitted the study of sulfonate solvation, proton dissociation, and the formation of a hydrogen bonding network without a priori assumptions. It was shown that decreasing the distance between sulfonate groups increased proton dissociation, as well as the interactions between water molecules. As the sulfonate distance increased, connectivity among the water molecules decreased as they formed more isolated clusters around the sulfonate groups. The sulfonate distance and geometry were the most dominant factors in proton dissociation; however, the hydrophobic environment and nanoscale confinement became more important as the distance between sulfonate groups increased. © 2011 American Chemical Society.

Cui S.,University of Tennessee at Knoxville
Journal of Physical Chemistry B | Year: 2011

We have carried out Brownian dynamics calculations to investigate the effect of DNA-ion interaction on ion transport in a nanopore. We calculated the self-diffusion coefficient of monovalent ions in the presence of DNA in a nanopore and compared the result with that through an open pore, that is, without the presence of DNA. We find that the self-diffusion coefficient of the co-ions is essentially unaffected by the DNA. The self-diffusion coefficient of the counterions, on the other hand, is significantly reduced depending on the ion concentration. At high ion concentration, around 1 M, the effect of DNA on counterion diffusion is relatively small, causing a slight reduction in counterion diffusion coefficient. At low concentrations of a few millimolar, the effect is much larger, resulting in a reduction in counterion diffusion coefficient by a factor of about 2.5. The variation in the self-diffusion of the counterion is well described by accounting for the contributions from two components: the adsorbed counterions and the free counterions. Detailed dynamics of the DNA-counterion interaction is characterized by the varying length of the transient adsorption time of the counterions to the DNA charge sites and the exchange rate with the environment. This variation in counterion adsorption time is attributed to the ionic electric screening effect, which is in turn determined by the ion concentration. © 2011 American Chemical Society.

Glisson C.,University of Tennessee at Knoxville | Green P.,University of Tennessee at Knoxville
Child Abuse and Neglect | Year: 2011

Objective: This study examines the association of organizational climate, casework services, and youth outcomes in child welfare systems. Building on preliminary findings linking organizational climate to youth outcomes over a 3-year follow-up period, the current study extends the follow-up period to 7 years and tests main, moderating and mediating effects of organizational climate and casework services on outcomes. Methods: The study applies hierarchical linear models (HLMs) analyses to all 5 waves of the National Survey of Child and Adolescent Well-being (NSCAW) with a US nationwide sample of 1,678 maltreated youth aged 4-16 years and 1,696 caseworkers from 88 child welfare systems. Organizational climate is assessed on 2 dimensions, Engagement and Stress, with scales from the well established measure, Organizational Social Context (OSC); youth outcomes are measured as problems in psychosocial functioning with the Child Behavior Checklist (CBCL); and casework services are assessed with original scales developed for the study and completed by the maltreated youths' primary caregivers and caseworkers. Results: Maltreated youth served by child welfare systems with more engaged organizational climates have significantly better outcomes. Moreover, the quantity and quality of casework services neither mediate nor interact with the effects of organizational climate on youth outcomes. Conclusions: Organizational climate is associated with youth outcomes in child welfare systems, but a better understanding is needed of the mechanisms that link organizational climate to outcomes. In addition, there is a need for evidence-based organizational interventions that can improve the organizational climates and effectiveness of child welfare systems. © 2011 Elsevier Ltd.

Hu Q.,University of Tennessee at Knoxville | Li F.,University of Tennessee at Knoxville
IEEE Transactions on Smart Grid | Year: 2013

The smart grid initiative and electricity market operation drive the development known as demand-side management or controllable load. Home energy management has received increasing interest due to the significant amount of loads in the residential sector. This paper presents a hardware design of smart home energy management system (SHEMS) with the applications of communication, sensing technology, and machine learning algorithm. With the proposed design, consumers can easily achieve a real-time, price-responsive control strategy for residential home loads such as electrical water heater (EWH), heating, ventilation, and air conditioning (HVAC), electrical vehicle (EV), dishwasher, washing machine, and dryer. Also, consumers may interact with suppliers or load serving entities (LSEs) to facilitate the load management at the supplier side. Further, SHEMS is designed with sensors to detect human activities and then a machine learning algorithm is applied to intelligently help consumers reduce total payment on electricity without or with little consumer involvement. Finally, simulation and experiment results are presented based on an actual SHEMS prototype to verify the hardware system. © 2013 IEEE.

Purpose: Cancer survivors require follow-up care to ensure early detection of recurrence, management of late/long term effects, preventive screening for early detection of second primary malignancies, as well as other forms of preventive care. But not all survivors receive necessary follow-up care. Combining survivorship care plans and patient navigation may be a successful strategy to improve survivor’s receipt of necessary follow-up care. Methods: Using data from the 2010 LIVESTRONG online survey of cancer survivors (N = 3854), this study tested associations between receipt of follow-up care instructions (FCI) and treatment summaries (TS) paired with patient navigation (PN), and survivor’s receipt of cancer surveillance, preventive cancer screening, and attendance at regular medical appointments. Results: Survivors who received FCI, TS, and patient navigation were the most likely to report attendance at all medical appointments (aOR 4.17, 95 % CI 2.30, 7.57, p ≤.001) and receipt of preventive cancer screening (aOR 3.56, 95 % CI 2.28, 5.55, p ≤.001). Conclusions: Likelihood of receiving follow-up care was greatest when survivors received FCI, TS, and PN. This pairing appeared to be most beneficial for survivor’s attendance at medical appointments and receipt of preventive cancer screening. Implications for cancer survivors: By improving attendance at medical appointments and prevention cancer screening, pairing SCP and PN could benefit survivors through reduced recurrence, earlier recurrence detection, and prevention of second primaries. © 2015, Springer Science+Business Media New York.

Iwashita T.,University of Tennessee at Knoxville | Nicholson D.M.,Oak Ridge National Laboratory | Egami T.,University of Tennessee at Knoxville | Egami T.,Oak Ridge National Laboratory
Physical Review Letters | Year: 2013

The elementary excitations of vibration in solids are phonons. But in liquids phonons are extremely short lived and marginalized. In this Letter through classical and ab initio molecular dynamics simulations of the liquid state of various metallic systems we show that different excitations, the local configurational excitations in the atomic connectivity network, are the elementary excitations in high temperature metallic liquids. We also demonstrate that the competition between the configurational excitations and phonons determines the so-called crossover phenomenon in liquids. These discoveries open the way to the explanation of various complex phenomena in liquids, such as fragility and the rapid increase in viscosity toward the glass transition, in terms of these excitations. © 2013 American Physical Society.

Murdock C.R.,University of Tennessee at Knoxville | Hughes B.C.,University of Tennessee at Knoxville | Lu Z.,University of Tennessee at Knoxville | Jenkins D.M.,University of Tennessee at Knoxville
Coordination Chemistry Reviews | Year: 2013

A subclass of metal-organic frameworks (MOFs) undergoes a "breathing" phenomenon which is a reversible flexing of the framework as a function of adsorbed guest. The existence of multiple stable states in a single framework leads to the modification of the shape and size of the pores as a function of guest, and has encouraged researchers to consider innovative applications for these flexible materials. To assist in improving the designs of these breathing MOFs, a thorough understanding of the different mechanisms by which frameworks breathe, must be established. This review will classify current breathing mechanisms by designating which part of the framework will not flex. By classifying the dimensional rigidity within a framework, a more in-depth discussion of each breathing mechanism can be established. Additionally, strategies for the design and synthesis of the next generation of breathing MOFs based on the reviewed research are discussed. © 2013 Elsevier B.V.

Novikov V.N.,University of Tennessee at Knoxville | Novikov V.N.,Oak Ridge National Laboratory | Sokolov A.P.,University of Tennessee at Knoxville | Sokolov A.P.,Oak Ridge National Laboratory
Physical Review Letters | Year: 2013

It is shown that quantum effects lead to a significant decrease of the glass transition temperature Tg with respect to the melting temperature Tm, so that the ratio Tg/Tm can be much smaller than the typical value of 2/3 in materials where Tg is near or below ∼60 K. Furthermore, it is demonstrated that the viscosity or structural relaxation time in such low temperature glass formers should exhibit highly unusual temperature dependence, namely a decrease of the apparent activation energy upon approaching Tg (instead of traditional increase). © 2013 American Physical Society.

Cedeno D.,University of Tennessee at Knoxville | Bozell J.J.,University of Tennessee at Knoxville
Tetrahedron Letters | Year: 2012

Models of guaiacyl (G) and syringyl (S) subunits in lignin have been catalytically oxidized to their corresponding p-quinones in the presence of molecular oxygen. The oxidation of syringyl-like phenols readily occurred with 5-coordinate cobalt catalysts on which one of the ligands is a monodentate pyridine or imidazole base that coordinates axially to the metal. Formation of p-quinones with this system depends on the coordination of the axial base to the metal as influenced by its pK a and its size. The yield of p-quinones from guaiacyl models was markedly improved by the addition of a sterically hindered aliphatic nitrogen base that does not coordinate to the catalyst. A mechanism involving deprotonation of the phenol substrate by the bulky base is proposed. © 2012 Elsevier Ltd. All rights reserved.

Ellram L.M.,Miami University Ohio | Tate W.L.,University of Tennessee at Knoxville | Feitzinger E.G.,UTi Worldwide Inc.
Journal of Supply Chain Management | Year: 2013

Organizations monitor factor-markets for strategic inputs that directly contribute to the firms' unique advantage. Thus, managers may be unaware of essential supporting inputs that bundle with strategic inputs to sustain the organization's success. Increasingly, supply chain resources are part of that strategic bundle of resources essential for achieving the firm's competitive advantage. This research employs a conceptual theory-building approach to examine competition among diverse industries in factor-markets using the example of supply chain services and the relatively new lens of factor-market rivalry theory. Data relative to air cargo capacity in China, port capacity in South Vietnam and the U.S. port and rail system provide the context for theoretical and practical insights into the implications of factor-market rivalry on firm performance. © 2013 Institute for Supply Management, Inc.

Zhang Y.,University of Tennessee at Knoxville | Parker L.E.,University of Tennessee at Knoxville
Autonomous Agents and Multi-Agent Systems | Year: 2013

This paper focuses on task allocation with single-task robots, multi-robot tasks and instantaneous assignment, which has been shown to be strongly NP-hard. Although this problem has been studied extensively, few efficient approximation algorithms have been provided due to its inherent complexity. In this paper, we first provide discussions and analyses for two natural greedy heuristics for solving this problem. Then, a new greedy heuristic is introduced, which considers inter-task resource constraints to approximate the influence between different assignments in task allocation. Instead of only looking at the utility of the assignment, our approach computes the expected loss of utility (due to the assigned robots and task) as an offset and uses the offset utility for making the greedy choice. A formal analysis is provided for the new heuristic, which reveals that the solution quality is bounded by two different factors. A new algorithm is then provided to approximate the new heuristic for performance improvement. Finally, for more complicated applications, we extend this problem to include general task dependencies and provide a result on the hardness of approximating this new formulation. Comparison results with the two natural heuristics in simulation are provided for both formulations, which show that the new approach achieves improved performance. © 2012 The Author(s).

Guo C.,University of Tennessee at Knoxville | Li X.,University of Tennessee at Knoxville
International Journal of Production Economics | Year: 2014

This paper investigates an integrated supplier selection and inventory control problems in supply chain management by developing a mathematical model for a multi-echelon system. In particular, a buyer firm that consists of one warehouse and N identical retailers procures a type of product from a group of potential suppliers, which may have different prices, ordering costs, lead times and have restriction on minimum and maximum total order size, to satisfy stochastic demand. A continuous review system that implements the order quantity, reorder point (Q, R) inventory policy is considered in the proposed model. The objective is to select suppliers and to determine the optimal inventory policy that coordinates stock levels between each echelon of the systems while properly allocating orders among selected suppliers to maximize the expected profit. The model is solved by decomposing the mixed integer nonlinear programming model into two sub-models. Numerical experiments are conducted to evaluate the model and some managerial insights are obtained with sensitivity analysis. © 2014 Elsevier B.V.

Vick J.K.,University of Tennessee at Knoxville | Nebenfuhr A.,University of Tennessee at Knoxville
Journal of Integrative Plant Biology | Year: 2012

A striking characteristic of plant cells is that their organelles can move rapidly through the cell. This movement, commonly referred to as cytoplasmic streaming, has been observed for over 200 years, but we are only now beginning to decipher the mechanisms responsible for it. The identification of the myosin motor proteins responsible for these movements allows us to probe the regulatory events that coordinate organelle displacement with normal cell physiology. This review will highlight several recent developments that have provided new insight into the regulation of organelle movement, both at the cellular level and at the molecular level. © 2012 Institute of Botany, Chinese Academy of Sciences.

Simberloff D.,University of Tennessee at Knoxville
Ecological Engineering | Year: 2014

Recent critics of the effort to control biological invasions argue that the extent of the damage they cause is overblown or that, whatever the damage, the effort to control them is largely futile. The best-known invasion impacts - predation, herbivory, competition, parasitism, and hybridization - are at the population level and are joined by myriad other, more idiosyncratic impacts. Many of these impose staggering ecological, economic, and public health costs and are surely worth combating. Although major effects are not yet known for the majority of established introduced species, three facts suggest that many more impacts will ultimately be detected. First, only a small minority of introduced populations have been studied in detail. Second, some substantial impacts are subtle and have become evident only after intensive research, often at the ecosystem level. Third, an invasion debt exists, such that some introduced populations remain innocuous for an extended period before rapidly growing and spreading to become highly invasive. Many invasive populations have been eradicated or successfully managed at low levels, and technological advances have increased the range of invasions that can be attacked successfully. An effective early-warning, rapid-response system would greatly facilitate eradication of invaders and could be aided by organizing citizen volunteers and publicizing standard reporting procedures. For all these reasons, permitting new introductions should be done with great caution, and introductions detected quickly, before the species has spread widely, should be targeted for eradication if a feasible method can be identified. In the absence of eradication, maintenance of many invasive populations at low levels has proven possible by biological control, chemical control, and physical or mechanical control. New approaches from allied fields promise an even wider range of management possibilities. However, managing long-established invaders should be considered on a case-by-case basis, and in some cases ecological or social concerns may argue against management. © 2013 Elsevier B.V.

Ellram L.M.,Miami University Ohio | Tate W.L.,University of Tennessee at Knoxville | Petersen K.J.,University of Tennessee at Knoxville
Journal of Supply Chain Management | Year: 2013

This research uses data from a survey to explore the factors that affect organizations' manufacturing location decisions. Manufacturing location, more specifically the possibility of firms' nearshoring or reshoring, has received a great deal of recent attention, especially in the United States. This paper applies the location aspect of internalization theory to provide an understanding of what factors affect organizations' perceptions of the attractiveness of various regions as locations for owned manufacturing facilities. An exploratory factor analysis is used to develop factors that drive manufacturing location decisions. Multiple regression analysis is used to test the relationship between the drivers of manufacturing location decisions and movement of manufacturing into or out of a region, and overall perceived risk of a region. Findings indicate that various drivers have differential effects across regions. For example, while North America is viewed favorably for its trade policies over the next 3 years, the trade policies are also viewed as an increasing source of risk, possibly reflecting bipartisan conflicts. Three theoretical propositions are developed to advance the understanding of the current state of manufacturing location decisions from an internalization perspective. It appears that organizations are beginning to look at their manufacturing location decisions through a broader lens, giving more weight to supply chain issues as well as strategic factors. © 2013 Institute for Supply Management, Inc.

Burch-Smith T.M.,University of California at Berkeley | Zambryski P.C.,University of Tennessee at Knoxville
Annual Review of Plant Biology | Year: 2012

Plant cells are surrounded by cellulosic cell walls, creating a potential challenge to resource sharing and ormation exchange between individual cells. To overcome this, plants have evolved channels called plasmodesmata that provide cytoplasmic continuity between each cell and its immediate neighbors. We first review plasmodesmata basics their architecture, their origin, the types of cargo they transport, and their molecular components. The bulk of this review discusses the regulation of plasmodesmata formation and function. Historically, plasmodesmata research has focused intensely on uncovering regulatory or structural proteins that reside within or immediately adjacent to plasmodesmata. Recent findings, however, underscore that plasmodesmata are exquisitely sensitive to signals far removed from the plasmodesmal channel itself. Signals originating from molecules and pathways that regulate cellular homeostasis such as reactive oxygen species, organelle-organelle signaling, and organelle-nucleus signaling lead to astonishing alterations in gene expression that affect plasmodesmata formation and function. © 2012 by Annual Reviews. All rights reserved.

O'Meara B.C.,University of Tennessee at Knoxville
Systematic Biology | Year: 2010

Species delimitation and species tree inference are difficult problems in cases of recent divergence, especially when different loci have different histories. This paper quantifies the difficulty of jointly finding the division of samples to species and estimating a species tree without constraining the possible assignments a priori. It introduces a parametric and a nonparametric method, including new heuristic search strategies, to do this delimitation and tree inference using individual gene trees as input. The new methods were evaluated using thousands of simulations and 4 empirical data sets. These analyses suggest that the new methods, especially the nonparametric one, may provide useful insights for systematists working at the species level with molecular data. However, they still often return incorrect results.

Gilleaudeau G.J.,University of Tennessee at Knoxville | Kah L.C.,University of Tennessee at Knoxville
Precambrian Research | Year: 2013

Carbon isotope profiles of sedimentary strata are widely used as both a tool for stratigraphic correlation and as a mechanism for inferring important changes in Earth's biogeochemical cycles. Chemostratigraphic interpretations, however, often rely on the assumption that the isotopic composition of dissolved inorganic carbon (DIC) in the surface oceans is broadly homogeneous. At times of globally high sea level, when epicratonic (epeiric) environments dominate our sedimentary record, carbon isotope records reveal substantial lateral variability. Here we investigate lateral variability in the marine carbon isotope record from pericratonic to epicratonic environments of the Mesoproterozoic (~1.1Ga) Atar/El Mreiti Groups of the Taoudeni Basin, West Africa. Restricted-marine epicratonic environments are consistently 2-4‰ lighter than open-marine pericratonic environments, suggesting input of an isotopically light carbon source that preferentially affected epicratonic environments. In contrast to epicratonic environments in the Paleozoic, where input of isotopically light carbon is generally attributed to input of terrestrial organic matter, we suggest that in situ remineralization of organic carbon via anaerobic microbial cycling drove observed isotopic variability. Within epicratonic El Mreiti Group strata, the extent of organic matter remineralization (and thus degree of 13C depletion) is correlated with water depth, and associated with distinct differences in both total organic carbon (TOC) and pyrite concentration, suggesting a potential linkage to both the persistence of anoxia and the availability of sulfate within epicratonic environments. In such settings, the isotopic effects of organic carbon remineralization are potentially enhanced by either methane oxidation following methanogenic decomposition, or the intermittent oxidation of an enhanced dissolved organic carbon (DOC) pool. © 2013 Elsevier B.V.

Godsoe W.,University of Tennessee at Knoxville
Systematic Biology | Year: 2010

Traditionally, the goal of systematics has been to produce classifications that are both strongly supported and biologically meaningful. In recent years several authors have advocated complementing phylogenetic analyses with measures of another form of evolutionary change, ecological divergence. These analyses frequently rely on ecological niche models to determine if species have comparable environmental requirements, but it has heretofore been difficult to test the accuracy of these inferences. To address this problem, I simulate the geographic distributions of allopatric species with identical environmental requirements. I then test whether existing analyses based on geographic distributions will correctly infer that the 2 species' requirements are identical. This work demonstrates that when taxa disperse to different environments, many analyses can erroneously infer changes in environmental requirements, but the severity of the problem depends on the method used. As this could exaggerate the number of ecologically distinct taxa in a clade, I suggest diagnostics to mitigate this problem.

Balta J.B.,University of Tennessee at Knoxville | McSween Jr. H.Y.,University of Tennessee at Knoxville
Geology | Year: 2013

Shergottites, the most abundant martian meteorites, represent the best source of information about Mars' mantle and its dissolved water. If the mantle was wet, magmatic degassing could have supplied substantial water to the martian surface early in its history. Researchers have attempted to reconstruct the volatile contents of shergottite parental magmas, with recent analyses confirming that the shergottites contained significant water. However, water is not a passive tracer; it directly affects magma chemistry and physical properties. Deciphering the history of water on Mars requires understanding how that water affected the chemistry of the shergottites and how they fit within Mars' geologic history. Both topics present difficulties, as no shergottite-like rock has been found in stratigraphic context and there is debate over the timing of eruptions of shergottite-like magmas. Partial melting experiments on terrestrial basalts and new data from orbiters and rovers on Mars provide the information needed to overcome these difficulties and explain the role of water in shergottite magmas. Here we show that shergottite compositions and their martian geologic context can be explained by melting of an originally wet mantle that degassed over time. We also demonstrate that models for the evolution of the martian mantle that do not consider water fail to account for the shergottite compositions, surface distributions, and ages. Finally, we suggest that dehydration of the martian mantle has led to changes in magmatic chemistry over time, with shergottites representing melts of water-bearing mantle and rocks similar to nakhlites representing melts of other mantle sources. © 2013 Geological Society of America.

Fordyce J.A.,University of Tennessee at Knoxville
Proceedings of the Royal Society B: Biological Sciences | Year: 2010

Ehrlich and Raven proposed a model of coevolution where major host plant shifts of butterflies facilitate a burst of diversification driven by their arrival to a new adaptive zone. One prediction of this model is that reconstructions of historical diversification of butterflies should indicate an increase in diversification rate following major host shifts. Using reconstructed histories of 15 butterfly groups, I tested this prediction and found general agreement with Ehrlich and Raven's model. Butterfly lineages with an inferred major historical host shift showed evidence of diversification rate variation, with a significant acceleration following the host shift. Lineages without an inferred major host shift generally agreed with a constant-rate model of diversification. These results are consistent with the view that host plant associations have played a profound role in the evolutionary history of butterflies, and show that major shifts to chemically distinct plant groups leave a historical footprint that remains detectable today. © 2010 The Royal Society.

Gavrilets S.,University of Tennessee at Knoxville
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2015

I review the theoretical and experimental literature on the collective action problem in groups whose members differ in various characteristics affecting individual costs, benefits and preferences in collective actions. I focus on evolutionary models that predict how individual efforts and fitnesses, group efforts and the amount of produced collective goods depend on the group’s size and heterogeneity, as well as on the benefit and cost functions and parameters. I consider collective actions that aim to overcome the challenges from nature or win competition with neighbouring groups of co-specifics. I show that the largest contributors towards production of collective goods will typically be group members with the highest stake in it or for whom the effort is least costly, or those who have the largest capability or initial endowment. Under some conditions, such group members end up with smaller net pay-offs than the rest of the group. That is, they effectively behave as altruists. With weak nonlinearity in benefit and cost functions, the group effort typically decreases with group size and increases with within-group heterogeneity. With strong nonlinearity in benefit and cost functions, these patterns are reversed. I discuss the implications of theoretical results for animal behaviour, human origins and psychology. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Nagle N.N.,University of Tennessee at Knoxville
Geographical Analysis | Year: 2010

This article summarizes area-to-point (ATP) factorial kriging that allows the smoothing of aggregate, areal data into a continuous spatial surface. Unlike some other smoothing methods, ATP factorial kriging does not suppose that all of the data within an area are located at a centroid or other arbitrary point. Also, unlike some other smoothing methods, factorial kriging allows the user to utilize an autocovariance function to control the smoothness of the output. This is beneficial because the covariance function is a physically meaningful statement of spatial relationship, which is not the case when other spatial kernel functions are used for smoothing. Given a known covariance function, factorial kriging gives the smooth surface that is best in terms of minimizing the expected mean squared prediction error. I present an application of the factorial kriging methodology for visualizing the structure of employment density in the Denver metropolitan area. © 2010 The Ohio State University.

Gavrilets S.,University of Tennessee at Knoxville | Fortunato L.,University of Oxford | Fortunato L.,Santa Fe Institute
Nature Communications | Year: 2014

Conflict with conspecifics from neighbouring groups over territory, mating opportunities and other resources is observed in many social organisms, including humans. Here we investigate the evolutionary origins of social instincts, as shaped by selection resulting from between-group conflict in the presence of a collective action problem. We focus on the effects of the differences between individuals on the evolutionary dynamics. Our theoretical models predict that high-rank individuals, who are able to usurp a disproportional share of resources in within-group interactions, will act seemingly altruistically in between-group conflict, expending more effort and often having lower reproductive success than their low-rank group-mates. Similar behaviour is expected for individuals with higher motivation, higher strengths or lower costs, or for individuals in a leadership position. Our theory also provides an evolutionary foundation for classical equity theory, and it has implications for the origin of coercive leadership and for reproductive skew theory. © 2014 Macmillan Publishers Limited.

D'Souza D.H.,University of Tennessee at Knoxville | Su X.,University of Tennessee at Knoxville
Foodborne Pathogens and Disease | Year: 2010

Human noroviruses pose an emerging public health threat, and despite stringent control strategies, variant strains continue to spread and cause disease outbreaks. Routinely used chemical sanitizers, such as sodium hypochlorite though effective on food contact surfaces, require high concentrations to cause reduction in enteric viral titers. The aim of this study was to evaluate the efficacy of trisodium phosphate (TSP) against three human enteric virus surrogates, murine norovirus (MNV-1), feline calicivirus (FCV), and bacteriophage MS2 in comparison to routinely used sanitizers. Three concentrations of TSP (1%, 2%, and 5%) at different contact times (30sec and 1min) were evaluated against the surrogate viruses individually inoculated on formica coupons. Our results showed that 5% TSP was effective in obtaining a ≥6log 10 PFU reduction for MNV-1, FCV, and MS2 after a contact time of only 30sec or 1min similar to 10% household bleach (0.6% sodium hypochlorite, 5000ppm available chlorine) for high titers of FCV and MS2, and with ∼5log 10 reduction after either 30sec or 1min on low viral titers. However, 2% TSP for 1min resulted in ≥6log 10 PFU reduction for FCV and MS2, but only a 1.05 log 10 PFU reduction for MNV-1 at high titers, with similar results after 30sec. Decreasing TSP levels to 1% reduced FCV by ∼2.65log 10 PFU, MS2 by 4.5log 10 PFU at high titers, and no reduction for MNV-1 after 30-sec or 1min contact. Glutaraldehyde (2%) reduced FCV and MNV-1 titers by ∼6log 10 PFU; however, MS2 was reduced by only 3.22 and 3.74log 10 PFU after 30sec and 1min, respectively, while 70% ethanol was not effective in reducing the three viruses at either high or low titers at both contact times. Alternative control strategies using TSP with short contact times should benefit the food industry in reducing norovirus transmission. Copyright 2010, Mary Ann Liebert, Inc.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Chemical Engineering Science | Year: 2010

The mass transfer kinetic properties of 2.1. mm I.D. columns packed with core-shell (Kinetex) and totally porous (BEH) sub-2μm particles, operated at high flow rates, under high pressure gradient, are investigated and discussed. The differences between their kinetic performance at low, intermediate, and high velocities are explained by the Kinetex column having a smaller longitudinal diffusion than the BEH column (due to the lower internal porous volume), a larger eddy diffusion (due to a less well-packed bed, with significant trans-column velocity biases), and a smaller amplitude of the radial temperature gradient across the column diameter generated by friction of the mobile phase percolating the bed at high flow rates. This last observation is accounted for by the heat conductivity of the Kinetex bed being three times larger than that of the BEH bed. © 2010 Elsevier Ltd.

Gritti F.,University of Tennessee at Knoxville | Guiochon G.,University of Tennessee at Knoxville
Chemical Engineering Science | Year: 2010

Mass transfer kinetics in a particular column packed with 2.6μm Kinetex-C18 particles was measured using a series of non-invasive methods. According to the manufacturer, this column was the most efficient one in a lot of 133 columns of the same dimensions, packed with particles of the same batch, with an efficiency about 6% larger than the lot average. The total eddy diffusion term of this column was determined by subtracting from the experimental HETP data (1) the longitudinal diffusion term (given by the peak parking method); (2) the trans-particle solid-liquid mass transfer resistance term (given by the peak parking method and an axial diffusion model); and (3) the external film mass transfer resistance term (derived from the Wilson and Geankoplis correlation). The results are analyzed based on the general coupling theory of eddy diffusion of Giddings and are compared to those previously obtained with a column packed with 2.7μm Halo-C18 column, which also has a low eddy diffusion term. The particular column investigated shows no trans-column velocity bias and a smaller reduced short-range inter-channel eddy diffusion term than the Halo column. This result explains the unusual efficiency of this exceptionally well packed column. © 2010 Elsevier Ltd.

Trinh C.T.,University of Tennessee at Knoxville
Applied Microbiology and Biotechnology | Year: 2012

Elementary mode (EM) analysis based on the constraint-based metabolic network modeling was applied to elucidate and compare complex fermentative metabolisms of Escherichia coli for obligate anaerobic production of n-butanol and isobutanol. The result shows that the nbutanol fermentative metabolism was NADH-deficient, while the isobutanol fermentative metabolism was NADH redundant. E. coli could grow and produce n-butanol anaerobically as the sole fermentative product but not achieve the maximum theoretical n-butanol yield. In contrast, for the isobutanol fermentative metabolism, E. coli was required to couple with either ethanol- or succinate-producing pathway to recycle NADH. To overcome these "defective" metabolisms, EM analysis was implemented to reprogram the native fermentative metabolism of E. coli for optimized anaerobic production of n-butanol and isobutanol through multiple gene deletion (̃8-9 genes), addition (̃6-7 genes), up- and downexpression (̃6-7 genes), and cofactor engineering (e.g., NADH, NADPH). The designed strains were forced to couple both growth and anaerobic production of nbutanol and isobutanol, which is a useful characteristic to enhance biofuel production and tolerance through metabolic pathway evolution. Even though the n-butanol and isobutanol fermentative metabolisms were quite different, the designed strains could be engineered to have identical metabolic flux distribution in "core" metabolic pathways mainly supporting cell growth and maintenance. Finally, the model prediction in elucidating and reprogramming the native fermentative metabolism of E. coli for obligate anaerobic production of n-butanol and isobutanol was validated with published experimental data. © Springer-Verlag 2012.

Schaefferkoetter J.,University of Tennessee at Knoxville
Physics in medicine and biology | Year: 2013

Time-of-flight (TOF) and point spread function (PSF) modeling have been shown to improve PET reconstructions, but the impact on physicians in the clinical setting has not been thoroughly investigated. A lesion detection and localization study was performed using simulated lesions in real patient images. Four reconstruction schemes were considered: ordinary Poisson OSEM (OP) alone and combined with TOF, PSF, and TOF + PSF. The images were presented to physicians experienced in reading PET images, and the performance of each was quantified using localization receiver operating characteristic. Numerical observers (non-prewhitening and Hotelling) were used to identify optimal reconstruction parameters, and observer SNR was compared to the performance of the physicians. The numerical models showed good agreement with human performance, and best performance was achieved by both when using TOF + PSF. These findings suggest a large potential benefit of TOF + PSF for oncology PET studies, especially in the detection of small, low-intensity, focal disease in larger patients.

Beck A.W.,University of Tennessee at Knoxville | McSween Jr. H.Y.,University of Tennessee at Knoxville
Meteoritics and Planetary Science | Year: 2010

A few relatively unbrecciated olivine-rich diogenites consist of an equilibrium assemblage of olivine and magnesian orthopyroxene (harzburgite). More common diogenites with smaller amounts of olivine are breccias containing two distinct orthopyroxenes - one magnesian and one ferroan. These diogenites are mixtures of a harzburgite lithology that is more magnesian, with the "normal" orthopyroxenite lithology that is ferroan and may contain small amounts of plagioclase. Both lithologies likely formed by fractional crystallization in multiple plutons emplaced within the crust of asteroid 4 Vesta. Minor element trends in orthopyroxenes indicate that these plutons exhibited a range of compositions. We propose a revised taxonomy for the HED (howardites, eucrites, and diogenites) suite where all ultramafic samples are referred to as diogenites. Within this group, the prefixes dunitic, harzburgitic, and orthopyroxenitic are used to distinguish diogenites consisting of more than or equal to 90% olivine, olivine + orthopyroxene, and more than or equal to 90% orthopyroxene, respectively. The prefix polymict is used to describe brecciated mixtures of any of these rock types. The recognition that olivine is a significant phase in some diogenites is consistent with spectral interpretations of olivine in a deeply excavated crater on Vesta, and has important implications for the bulk composition and petrogenesis of that body. © 2010 The Meteoritical Society.

Singh V.,University of Tennessee at Knoxville | Holt L.,Instructional Technology
Computers and Education | Year: 2013

This research is about participants who use open-source software (OSS) discussion forums for learning. Learning in online communities of education as well as non-education-related online communities has been studied under the lens of social learning theory and situated learning for a long time. In this research, we draw parallels among these two types of communities and explore what can be learned from open-source software communities about online learning. Thematic network analysis was used to code the qualitative data from the open-ended questions in the survey and the interviews. The results indicate that learning in online open-source software communities encompasses much more than just learning about the software being discussed. 283 Open-source forum participants were surveyed, and 21 were interviewed to develop an understanding of the challenges to learning in these communities as well as to identify the practices that promote learning. Identifying these practices helps to understand online learning and enables the integration of best practices into online education. © 2012 Elsevier Ltd. All rights reserved.

Singh V.,University of Tennessee at Knoxville
Information Technology and Libraries | Year: 2013

Interest in migrating to open-source integrated library systems is continually growing in libraries. Along with the interest, lack of empirical research and evidence to compare the process of migration brings a lot of anxiety to the interested librarians. In this research, twenty librarians who have worked in libraries that migrated to open-source integrated library system (ILS) or are in the process of migrating were interviewed. The interviews focused on their experiences and the lessons learned in the process of migration. The results from the interviews are used to create guidelines/best practices for each stage of the adoption process of an open-source ILS. These guidelines will be helpful for librarians who want to research and adopt an open-source ILS.