Madison, WI, United States
Madison, WI, United States

The University of Wisconsin–Madison is a selective public research university located in Madison, Wisconsin, United States. Founded when Wisconsin achieved statehood in 1848, UW–Madison is the official state university of Wisconsin, and the flagship campus of the University of Wisconsin System. It was the first public university established in Wisconsin and remains the oldest and largest public university in the state. It became a land-grant institution in 1866. The 933-acre main campus includes four National Historic Landmarks.UW–Madison is organized into 20 schools and colleges, which enrolled 29,504 undergraduate, 9,430 graduate, and 2,526 professional students and granted 6,494 bachelor's, 3,560 graduate and professional degrees in 2012-2013. The University employs over 21,727 faculty and staff. Its comprehensive academic program offers 132 undergraduate majors, along with 149 master's degree programs and 120 doctoral programs.The UW is categorized as an RU/VH Research University in the Carnegie Classification of Institutions of Higher Education. In 2012, it had research expenditures of more than $1.1 billion, the third highest among universities in the country. Wisconsin is a founding member of the Association of American Universities.The Wisconsin Badgers compete in 25 intercollegiate sports in the NCAA's Division I Big Ten Conference and have won 28 national championships. Wikipedia.


Time filter

Source Type

Liu Z.,University of Wisconsin - Madison | Liu Z.,Peking University
Journal of Climate | Year: 2012

The emerging interest in decadal climate prediction highlights the importance of understanding the mechanisms of decadal to interdecadal climate variability. The purpose of this paper is to provide a review of our understanding of interdecadal climate variability in the Pacific and Atlantic Oceans. In particular, the dynamics of interdecadal variability in both oceans will be discussed in a unified framework and in light of historical development. General mechanisms responsible for interdecadal variability, including the role of ocean dynamics, are reviewed first. A hierarchy of increasingly complex paradigms is used to explain variability. This hierarchy ranges from a simple red noise model to a complex stochastically driven coupled ocean-atmosphere mode. The review suggests that stochastic forcing is the major driving mechanism for almost all interdecadal variability, while ocean-atmosphere feedback plays a relatively minor role. Interdecadal variability can be generated independently in the tropics or extratropics, and in the Pacific or Atlantic. In the Pacific, decadal-interdecadal variability is associated with changes in the wind-driven upper-ocean circulation. In the North Atlantic, some of the multidecadal variability is associated with changes in the Atlantic meridional overturning circulation (AMOC). In both the Pacific and Atlantic, the time scale of interdecadal variability seems to be determined mainly by Rossby wave propagation in the extratropics; in the Atlantic, the time scale could also be determined by the advection of the returning branch of AMOC in the Atlantic. One significant advancement of the last two decades is the recognition of the stochastic forcing as the dominant generation mechanism for almost all interdecadal variability. Finally, outstanding issues regarding the cause of interdecadal climate variability are discussed. The mechanism that determines the time scale of each interdecadal mode remains one of the key issues not understood. It is suggested that much further understanding can be gained in the future by performing specifically designed sensitivity experiments in coupled ocean-atmosphere general circulation models, by further analysis of observations and cross-model comparisons, and by combining mechanistic studies with decadal prediction studies. © 2012 American Meteorological Society.


Ives A.R.,University of Wisconsin - Madison | Garland T.,University of California at Riverside
Systematic Biology | Year: 2010

We develop statistical methods for phylogenetic logistic regression in which the dependent variable is binary (0 or 1) and values are nonindependent among species, with phylogenetically related species tending to have the same value of the dependent variable. The methods are based on an evolutionary model of binary traits in which trait values switch between 0 and 1 as species evolve up a phylogenetic tree. The more frequently the trait values switch (i.e., the higher the rate of evolution), the more rapidly correlations between trait values for phylogenetically related species break down. Therefore, the statistical methods also give a way to estimate the phylogenetic signal of binary traits. More generally, the methods can be applied with continuous-and/or discrete-valued independent variables. Using simulations, we assess the statistical properties of the methods, including bias in the estimates of the logistic regression coefficients and the parameter that estimates the strength of phylogenetic signal in the dependent variable. These analyses show that, as with the case for continuous-valued dependent variables, phylogenetic logistic regression should be used rather than standard logistic regression when there is the possibility of phylogenetic correlations among species. Standard logistic regression does not properly account for the loss of information caused by resemblance of relatives and as a result is likely to give inflated type I error rates, incorrectly identifying regression parameters as statistically significantly different from zero when they are not.


Studer A.,University of Wisconsin - Madison | Zhao Q.,University of Wisconsin - Madison | Ross-Ibarra J.,University of California at Davis | Doebley J.,University of Wisconsin - Madison
Nature Genetics | Year: 2011

Genetic diversity created by transposable elements is an important source of functional variation upon which selection acts during evolution. Transposable elements are associated with adaptation to temperate climates in Drosophila, a SINE element is associated with the domestication of small dog breeds from the gray wolf and there is evidence that transposable elements were targets of selection during human evolution. Although the list of examples of transposable elements associated with host gene function continues to grow, proof that transposable elements are causative and not just correlated with functional variation is limited. Here we show that a transposable element (Hopscotch) inserted in a regulatory region of the maize domestication gene, teosinte branched1 (tb1), acts as an enhancer of gene expression and partially explains the increased apical dominance in maize compared to its progenitor, teosinte. Molecular dating indicates that the Hopscotch insertion predates maize domestication by at least 10,000 years, indicating that selection acted on standing variation rather than new mutation. © 2011 Nature America, Inc. All rights reserved.


Kampinga H.H.,University of Groningen | Craig E.A.,University of Wisconsin - Madison
Nature Reviews Molecular Cell Biology | Year: 2010

Heat shock 70 kDa proteins (HSP70s) are ubiquitous molecular chaperones that function in a myriad of biological processes, modulating polypeptide folding, degradation and translocation across membranes, and proteinĝ€"protein interactions. This multitude of roles is not easily reconciled with the universality of the activity of HSP70s in ATP-dependent client protein-binding and release cycles. Much of the functional diversity of the HSP70s is driven by a diverse class of cofactors: J proteins. Often, multiple J proteins function with a single HSP70. Some target HSP70 activity to clients at precise locations in cells and others bind client proteins directly, thereby delivering specific clients to HSP70 and directly determining their fate. © 2010 Macmillan Publishers Limited. All rights reserved.


Grant
Agency: Department of Defense | Branch: Air Force | Program: STTR | Phase: Phase II | Award Amount: 749.92K | Year: 2013

ABSTRACT: Agiltron and the University of WisconsinMadison will develop the first SWIR Image Sensor with a flexible FPA. The sensor is based on the integration of single-crystal Si and Ge nanomembranes, which has the potential to achieve defect-free Ge-based photodiodes for SWIR imaging while eliminating the need for an epitaxial step. In Phase I, we have successfully demonstrated Ge-based PIN photodiodes with SWIR responsivity and bulk-like dark current. In Phase II, we will build and test a complete SWIR Image Sensor featuring a fully-flexible FPA. BENEFIT: This program addresses the lack of SWIR image sensors with array sizes larger than 10241024 and pixel pitches smaller than 10 & #956;m. Increasing the resolution and sensitivity in SWIR imaging is critical for night-vision applications such as surveillance, passive imaging, target acquisition and designation, and forward observation, and for insertion into Intelligence, Surveillance and Reconnaissance (ISR) military and security systems. In addition, developing imaging technology on flexible substrates allows new system capabilities such as a tunable field of view and reduced imaging optics complexity. This will enable high-performance, low-SWAP imagers with a field of view that far exceeds the state of the art possible with planar focal plane arrays.


Barbey A.K.,University of Illinois at Urbana - Champaign | Koenigs M.,University of Wisconsin - Madison | Grafman J.,Traumatic Brain Injury Research Laboratory
Cortex | Year: 2013

Although neuroscience has made remarkable progress in understanding the involvement of prefrontal cortex (PFC) in human memory, the necessity of dorsolateral PFC (dlPFC) for key competencies of working memory remains largely unexplored. We therefore studied human brain lesion patients to determine whether dlPFC is necessary for working memory function, administering subtests of the Wechsler Memory Scale, the Wechsler Adult Intelligence Scale, and the N-Back Task to three participant groups: dlPFC lesions (n = 19), non-dlPFC lesions (n = 152), and no brain lesions (n = 54). DlPFC damage was associated with deficits in the manipulation of verbal and spatial knowledge, with left dlPFC necessary for manipulating information in working memory and right dlPFC critical for manipulating information in a broader range of reasoning contexts. Our findings elucidate the architecture of working memory, providing key neuropsychological evidence for the necessity of dlPFC in the manipulation of verbal and spatial knowledge. © 2012 Elsevier Ltd.


Grant
Agency: GTR | Branch: EPSRC | Program: | Phase: Research Grant | Award Amount: 1.55M | Year: 2013

This proposal sits within a field of great scope, stretching from some of the most fundamental problems in physics, to current practical issues in engineering, to some of the most powerful modern techniques in topology and geometry. Although these topics are all very different, it has become apparent that many of the biggest future developments in each area will require overcoming key research challenges that are remarkably similar. It is these challenges that we will address in this proposed research. At the heart of each of the topics above lie Geometric Partial Differential Equations (PDE). Each of these equations could be perhaps a law of physics, or an equation modelling an industrial process, or more abstractly, a rule under which a geometric object can be processed in order to improve it. Smooth solutions to Geometric PDE have been extremely successful in applications to pure and applied problems, but the equations are generally nonlinear, and it is therefore typical that singularities will occur in solutions. The next generation of applications, with extensive potential impact, require us to transform our understanding of these singularities that develop. We must understand when and why they occur, their structure and stability, and how they encode what the PDE is doing. We must analyse to what extent they break the classical theory of smooth solutions, and what effects this has. These are the main challenges of this proposal, and we have compiled a team to address them with complementary expertise in singularity analysis and experience of applying geometric PDE across subjects such as Mathematical Relativity, Geometric Flows and Minimal Surfaces. In Mathematical Relativity, one sees singularities in solutions of the Einstein equations, first written down by Einstein in 1915 as the fundamental equations of the large-scale universe. Progress in the research challenges we propose will have potentially major impact in some of the most famous open problems in this field such as the Cosmic Censorship Conjectures, and the Black Hole Stability Problem. We also find singularities in the field of Geometric Flows, by which we mean the evolution equations of `parabolic type that are currently being so successful in applications to geometry, topology and engineering, and in modelling phenomena in physics and biology. The most famous application in recent years has been the resolution of the Poincaré conjecture, which was named by the journal `Science as the scientific `Breakthrough of the year, 2006, but is considered by many to be the greatest achievement of mathematics in the past 100 years. The research challenges we propose are central to future applications of these equations, whether we are using them to classify manifolds with a certain curvature condition, or manipulate an image from a medical scanner. Intimately connected with these two subjects is the theory of Minimal Surfaces. These surfaces have been historically used to model soap films, but the general theory has developed into a powerful tool with applications to a wide range of subjects from black holes to topology. In this direction, we are particularly interested in applying progress on the research challenges of this proposal to unravel the connection between the existence of higher-index minimal surfaces and the singularities that occur in flows and variational problems that are designed to find them.


Grant
Agency: National Aeronautics and Space Administration | Branch: | Program: STTR | Phase: Phase II | Award Amount: 748.22K | Year: 2012

In this STTR effort, Los Gatos Research (LGR) and the University of Wisconsin (UW) propose to develop a highly-accurate sensor for high-purity oxygen determination. The analyzer, which is based on LGR's patented Off-Axis ICOS technique, will be capable of rapidly quantifying high-purity oxygen (95 – 100 %) with very high accuracy (better than ? 0.03 %), minimal calibration, and no zero drift. Moreover, the sensor will require no consumables and be sufficiently compact and robust for deployment aboard the International Space Station (ISS). In Phase I, LGR and UW successfully demonstrated technical feasibility by fabricating a prototype that quantified high-purity oxygen with a precision of ? 0.017 % and a 24-hour drift of less than 0.05 %. The analyzer distinguished a 0.1 % change in highly pure oxygen and provided a linear response (R2 = 0.999997) over a wide dynamic range (0 – 100 % oxygen). The prototype was found to be accurate to 0.07 % by testing it at NASA Johnson Space Center on oxygen purified by the Cabin Air Separator for EVA Oxygen (CASEO) project. Due to the success of this program, LGR released a commercial O2/CO2 analyzer for environmental applications. In Phase II, LGR and UW will refine the measurement strategy, miniaturize the hardware, ruggedize the analyzer, and test the resulting instrument. The measurement strategy will be improved to reduce long-term drift and extended to include other species (H2O, O2 isotopes, N2). The hardware will be modified to meet the technical requirements for deployment aboard the ISS (e.g. power, size, weight, and environmental specifications). The prototype will be manufactured and tested to empirically determine its accuracy, precision, linearity, long-term drift, and time response. Finally, the Phase II instrument will be delivered to researchers in the Life Support and Habitability Systems Branch at NASA Johnson Space Centers for characterization of high-purity oxygen generators.


Grant
Agency: GTR | Branch: EPSRC | Program: | Phase: Fellowship | Award Amount: 807.01K | Year: 2015

Complex fluid flows are ubiquitous in both the natural and man-made worlds. From the pulsatile flow of blood through our bodies, to the pumping of personal products such as shampoos or conditioners through complex piping networks as they are processed. For such complex fluids the underlying microstructure can give rise to flow instabilities which are often totally absent in simple Newtonian fluids such as water or air. For example, many wormlike micellar surfactant (soap/detergent) systems are known to exhibit shear-banding where the homogenous solution splits into two (or more) bands of fluid: such flows are often unstable to even infinitesimally small perturbations. At higher pump speeds the flows can develop chaotic motion caused by the elastic normal-stresses developed in flow. Such elastic turbulence can also develop for other flowing complex fluids, such as polymer solutions and melts, and give rise to new phenomena. Often such instabilities are unwelcome, for example in rheometric devices when the aim is to measure material properties or in simple pumping operations when they can give rise to unacceptably large pressure drops and prevent pumping. In other cases they can give rise to enhanced mixing of heat and mass which would otherwise be difficult to achieve (e.g. microfluidics applications).


Grant
Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase I | Award Amount: 79.94K | Year: 2015

The objective of the proposed Phase-I effort proposed by Spectral Energies LLC is to develop a versatile hyperspectral sensor system capable of performing >100 kHz in situ temperature and species concentration measurements of CO, CO2 and H2O in rotating detonation engines (RDEs) for gas temperatures up to 3000 K and gas pressures up to 50 bar. Development will include both the laser system as well as strategies for optical access into the RDE. The proposed laser system will consist of two main aspects. First, a broad scanning near-IR laser will used to measure high precision H2O temperatures at 100 kHz. In addition, another system consisting of several frequency-division-multiplexed fixed wavelength lasers will be used to determine CO, CO2 and H2O concentrations and temperatures at 800 kHz. Preliminary measurements using existing available hardware will be used to measure H2O, CO and CO2 concentrations and temperatures in an RDE facility located at the University of Cincinnati in Cincinnati, OH. Based on the Phase-I results, we propose to design, build and deliver a compact dedicated sensor system along with robust optical access tools for measuring temperature and species concentrations at speeds up to 800 kHz along multiple lines-of-sight during the Phase-II research effort.


Veasey S.C.,University of Pennsylvania | Morgan B.J.,University of Wisconsin - Madison | O'Donnell C.P.,University of Pittsburgh
Physiological Reviews | Year: 2010

Sleep-induced apnea and disordered breathing refers to intermittent, cyclical cessations or reductions of airflow, with or without obstructions of the upper airway (OSA). In the presence of an anatomically compromised, collapsible airway, the sleep-induced loss of compensatory tonic input to the upper airway dilator muscle motor neurons leads to collapse of the pharyngeal airway. In turn, the ability of the sleeping subject to compensate for this airway obstruction will determine the degree of cycling of these events. Several of the classic neurotransmitters and a growing list of neuromodulators have now been identified that contribute to neurochemical regulation of pharyngeal motor neuron activity and airway patency. Limited progress has been made in developing pharmacotherapies with acceptable specificity for the treatment of sleep-induced airway obstruction. We review three types of major long-term sequelae to severe OSA that have been assessed in humans through use of continuous positive airway pressure (CPAP) treatment and in animal models via long-term intermittent hypoxemia (IH): 1) cardiovascular. The evidence is strongest to support daytime systemic hypertension as a consequence of severe OSA, with less conclusive effects on pulmonary hypertension, stroke, coronary artery disease, and cardiac arrhythmias. The underlying mechanisms mediating hypertension include enhanced chemoreceptor sensitivity causing excessive daytime sympathetic vasoconstrictor activity, combined with overproduction of superoxide ion and inflammatory effects on resistance vessels. 2) Insulin sensitivity and homeostasis of glucose regulation are negatively impacted by both intermittent hypoxemia and sleep disruption, but whether these influences of OSA are sufficient, independent of obesity, to contribute significantly to the "metabolic syndrome" remains unsettled. 3) Neurocognitive effects include daytime sleepiness and impaired memory and concentration. These effects reflect hypoxic-induced "neural injury." We discuss future research into understanding the pathophysiology of sleep apnea as a basis for uncovering newer forms of treatment of both the ventilatory disorder and its multiple sequelae. Copyright © 2010 the American Physiological Society.


Holeski L.M.,University of Wisconsin - Madison | Jander G.,Boyce Thompson Institute for Plant Research | Agrawal A.A.,Cornell University
Trends in Ecology and Evolution | Year: 2012

Rapidly accumulating evidence shows that herbivore and pathogen attack of plants can generate particular defense phenotypes across generations. What was once thought to be an oddity of plant defense induction now appears to be a taxonomically widespread phenomenon with strong potential to impact the ecology and evolution of species interactions. DNA methylation, histone modifications, and small RNAs each contribute to transgenerational defense initiation; examples in several species demonstrate that this induction can last for multiple generations. Priming of the offspring generation for more rapid induction following subsequent attack has also been reported. The extent to which transgenerational induction is predictable, detectable in nature, and subject to manipulation will determine the ability of researchers to decipher its role in plant-herbivore and plant-pathogen interactions. © 2012 Elsevier Ltd.


Fernandes R.M.,University of Minnesota | Chubukov A.V.,University of Wisconsin - Madison | Schmalian J.,Karlsruhe Institute of Technology
Nature Physics | Year: 2014

Although the existence of nematic order in iron-based superconductors is now a well-established experimental fact, its origin remains controversial. Nematic order breaks the discrete lattice rotational symmetry by making the x and y directions in the iron plane non-equivalent. This can happen because of a regular structural transition or as the result of an electronically driven instability-in particular, orbital order or spin-driven Ising-nematic order. The latter is a magnetic state that breaks rotational symmetry but preserves time-reversal symmetry. Symmetry dictates that the development of one of these orders immediately induces the other two, making the origin of nematicity a physics realization of the 'chicken and egg problem'. In this Review, we argue that the evidence strongly points to an electronic mechanism of nematicity, placing nematic order in the class of correlation-driven electronic instabilities, like superconductivity and density-wave transitions. We discuss different microscopic models for nematicity and link them to the properties of the magnetic and superconducting states, providing a unified perspective on the phase diagram of the iron pnictides. © 2014 Macmillan Publishers Limited.


Wuthrich M.,University of Wisconsin - Madison | Deepe Jr. G.S.,Veterans Affairs Hospital | Deepe Jr. G.S.,University of Cincinnati | Klein B.,University of Wisconsin - Madison
Annual Review of Immunology | Year: 2012

Only a handful of the more than 100,000 fungal species on our planet cause disease in humans, yet the number of life-threatening fungal infections in patients has recently skyrocketed as a result of advances in medical care that often suppress immunity intensely. This emerging crisis has created pressing needs to clarify immune defense mechanisms against fungi, with the ultimate goal of therapeutic applications. Herein, we describe recent insights in understanding the mammalian immune defenses deployed against pathogenic fungi. The review focuses on adaptive immune responses to the major medically important fungi and emphasizes how dendritic cells and subsets in various anatomic compartments respond to fungi, recognize their molecular patterns, and signal responses that nurture and shape the differentiation of T cell subsets and B cells. Also emphasized is how the latter deploy effector and regulatory mechanisms that eliminate these nasty invaders while also constraining collateral damage to vital tissue. © 2012 by Annual Reviews. All rights reserved.


Saffman M.,University of Wisconsin - Madison | Walker T.G.,University of Wisconsin - Madison | Molmer K.,University of Aarhus
Reviews of Modern Physics | Year: 2010

Rydberg atoms with principal quantum number n 1 have exaggerated atomic properties including dipole-dipole interactions that scale as n4 and radiative lifetimes that scale as n3. It was proposed a decade ago to take advantage of these properties to implement quantum gates between neutral atom qubits. The availability of a strong long-range interaction that can be coherently turned on and off is an enabling resource for a wide range of quantum information tasks stretching far beyond the original gate proposal. Rydberg enabled capabilities include long-range two-qubit gates, collective encoding of multiqubit registers, implementation of robust light-atom quantum interfaces, and the potential for simulating quantum many-body physics. The advances of the last decade are reviewed, covering both theoretical and experimental aspects of Rydberg-mediated quantum information processing. © 2010 The American Physical Society.


Burdick J.A.,University of Pennsylvania | Murphy W.L.,University of Wisconsin - Madison
Nature Communications | Year: 2012

Hydrogels are water-swollen polymer networks that have found a range of applications from biological scaffolds to contact lenses. Historically, their design has consisted primarily of static systems and those that exhibit simple degradation. However, advances in polymer synthesis and processing have led to a new generation of dynamic systems that are capable of responding to artificial triggers and biological signals with spatial precision. These systems will open up new possibilities for the use of hydrogels as model biological structures and in tissue regeneration. © 2012 Macmillan Publishers Limited. All rights reserved.


Grant
Agency: National Science Foundation | Branch: | Program: STTR | Phase: Phase I | Award Amount: 225.00K | Year: 2016

The broader impact/commercial potential of this Small Business Innovation Research Phase I project is to enable anyone with internet to access extremely powerful computing facilities to perform scientific computing. High performance computing is essential for computational prototyping in many areas of modern engineering, such as solar cells, automobiles, aerospace, and communication devices. However, significant barriers make it difficult for ordinary engineers to easily access powerful computing facilities. By leveraging the low-cost commercial cloud, the project will develop key technology that allow commercial clouds to perform extremely high performance scientific computing, thereby significantly reducing the cost and increasing the accessibility of high performance computing. This Small Business Innovation Research (SBIR) Phase I project will develop technologies that overcome key challenges in using commercial clouds for high performance computing. Unlike high performance computers, commercial clouds are not designed for scientific computing. They have high latency, intermitted availability, and heterogeneously distributed resources. These features make it difficult to conduct scientific computing. This project will develop new computing methods that fully take into account the heterogeneous nature of the commercial cloud. It enables anyone to access high performance scientific computing anywhere with an easy-to-use interface. Computing is provided as on-demand service. Engineers would not need to own any high performance computers and the computing resources are virtually unlimited.


Storz G.,Eunice Kennedy Shriver National Institute of Child Health and Human Development | Vogel J.,University of Würzburg | Wassarman K.,University of Wisconsin - Madison
Molecular Cell | Year: 2011

Research on the discovery and characterization of small, regulatory RNAs in bacteria has exploded in recent years. These sRNAs act by base pairing with target mRNAs with which they share limited or extended complementarity, or by modulating protein activity, in some cases by mimicking other nucleic acids. Mechanistic insights into how sRNAs bind mRNAs and proteins, how they compete with each other, and how they interface with ribonucleases are active areas of discovery. Current work also has begun to illuminate how sRNAs modulate expression of distinct regulons and key transcription factors, thus integrating sRNA activity into extensive regulatory networks. In addition, the application of RNA deep sequencing has led to reports of hundreds of additional sRNA candidates in a wide swath of bacterial species. Most importantly, recent studies have served to clarify the abundance of remaining questions about how, when, and why sRNA-mediated regulation is of such importance to bacterial lifestyles. © 2011 Elsevier Inc.


Bai Y.,University of Wisconsin - Madison | Berger J.,SLAC
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

Recent searches for a first-generation leptoquark by the CMS collaboration have shown around 2.5σ deviations from Standard Model predictions in both the eejj and eνjj channels. Furthermore, the eejj invariant mass distribution has another 2.8σ excess from the CMS right-handed W plus heavy neutrino search. We point out that additional leptoquark production from a heavy coloron decay can provide a good explanation for all three excesses. The coloron has a mass around 2.1 TeV and the leptoquark mass can vary from 550 GeV to 650 GeV. A key prediction of this model is an edge in the total mT distribution of eνjj events at around 2.1 TeV. © 2015 The Authors.


Foster M.J.,University of Wisconsin - Madison | Heidinger A.,The Center for Satellite Applications and Research
Journal of Climate | Year: 2013

Satellite drift is a historical issue affecting the consistency of those few satellite records capable of being used for studies on climate time scales. Here, the authors address this issue for the Pathfinder Atmospheres Extended (PATMOS-x)/Advanced Very High Resolution Radiometer (AVHRR) cloudiness record, which spans three decades and 11 disparatesensors.Atwo-harmonic sinusoidal function is fit to a mean diurnal cycle of cloudiness derived over the course of the entire AVHRRrecord. The authors validate this function against measurements from Geostationary Operational Environmental Satellite (GOES) sensors, finding good agreement, and then test the stability of the diurnal cycle over the course ofthe AVHRR record. It is found that the diurnal cycle is subject to some interannual variability over land but that the differences are somewhat offset when averaged over an entire day. The fit function is used to generate daily averaged time series of ice, water, andtotal cloudiness over the tropics, where it is found that the diurnal correction affects the magnitude and even the sign of long-term cloudiness trends. A statistical method is applied to determine the minimum length of time required to detect significant trends, andthe authors find that only recently have they begun generating satellite records of sufficient length to detect trends in cloudiness. © 2013 American Meteorological Society.


Huttenlocher A.,University of Wisconsin - Madison | Horwitz A.R.,University of Virginia
Cold Spring Harbor Perspectives in Biology | Year: 2011

Integrin-based adhesion has served as a model for studying the central role of adhesion in migration. In this article, we outline modes of migration, both integrin-dependent and -independent in vitro and in vivo. We next discuss the roles of adhesion contacts as signaling centers and linkages between the ECM and actin that allows adhesions to serve as traction sites. This includes signaling complexes that regulate migration and the interplay among adhesion, signaling, and pliability of the substratum. Finally, we address mechanisms of adhesion assembly and disassembly and the role of adhesion in cellular polarity. © 2011 Cold Spring Harbor Laboratory Press.


Grant
Agency: Department of Defense | Branch: Army | Program: STTR | Phase: Phase II | Award Amount: 999.98K | Year: 2014

In Phase I we successfully reached all goals and milestones in developing liquid crystal sensors that detected 100 ppb of each of four target gases (DMMP, hydrogen sulfide, nitrogen dioxide and ammonia) within 60 seconds. In Phase II, we propose to expand this detection capability to a total of seven gases, adding volatile organic compounds, chlorine and half-mustard to the set. We then propose to develop three types of sensors for three gases (threshold, semi-quantitative and quantitative), develop a subsystem for integration of threshold sensors into unmanned vehicles, and test one of the sensors on the ARA Pointman robot. Our first target product for Phase II is a threshold sensor for hydrogen sulfide suitable for integration with unmanned ground vehicles.


Grant
Agency: Department of Defense | Branch: Army | Program: STTR | Phase: Phase I | Award Amount: 150.00K | Year: 2013

We aim to develop lightweight and rugged liquid crystal (LC)-based sensors suitable for integration into small unmanned vehicles, including hand-launched UAVs and throwable robots. For Phase I proof of concept, we propose to develop sensors that detect DMMP, H2S, NO2 and NH3. These gases include simulants of chemical warfare agents and toxic industrial chemicals, selected for their relevance to DoD and civilian security. The sensors will be fabricated and tested through a collaboration between Platypus Technologies LLC and University of Wisconsin. We will (i) optimize the design of chemically functionalized surfaces to enable sensitive LC-based detection of the target gases; (ii) perform infrared spectroscopy to advance our understanding of the intermolecular interactions that underlie the response of the LC sensors to the targeted gases, so that we will be better able to design further improvements and broader detection capabilities in Phase II; and (iii) design and fabricate simple microstructures that host LCs in a manner suitable for fabrication of LC sensors for deployment in small UMVs. Benefits of these sensors include their robustness and uniquely low power and weight parameters, which facilitate their use in small UMVs. Commercial applications extend to civilian markets such as monitoring gas pipelines, wells, mines.


Francis J.A.,Rutgers University | Vavrus S.J.,University of Wisconsin - Madison
Geophysical Research Letters | Year: 2012

Arctic amplification (AA)-the observed enhanced warming in high northern latitudes relative to the northern hemisphere-is evident in lower-tropospheric temperatures and in 1000-to-500hPa thicknesses. Daily fields of 500hPa heights from the National Centers for Environmental Prediction Reanalysis are analyzed over N. America and the N. Atlantic to assess changes in north-south (Rossby) wave characteristics associated with AA and the relaxation of poleward thickness gradients. Two effects are identified that each contribute to a slower eastward progression of Rossby waves in the upper-level flow: 1) weakened zonal winds, and 2) increased wave amplitude. These effects are particularly evident in autumn and winter consistent with sea-ice loss, but are also apparent in summer, possibly related to earlier snow melt on high-latitude land. Slower progression of upper-level waves would cause associated weather patterns in mid-latitudes to be more persistent, which may lead to an increased probability of extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves. copyright 2012 by the American Geophysical Union.


Ahlers M.,University of Wisconsin - Madison | Murase K.,Hubble Fellow Institute for Advanced Study
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

The IceCube Collaboration has recently reported evidence for a high-energy extraterrestrial neutrino flux. During two years of operation 28 events with energies between 30 TeV and 1.2 PeV were observed while only 10.6 events were expected from conventional atmospheric backgrounds. The hadronic interactions responsible for this IceCube excess will also produce a flux of high-energy γ-rays that can serve as a probe of source direction and distance. We show that existing TeV to PeV diffuse γ-ray limits support the interpretation that the IceCube excess is mostly of extragalactic origin. However, we point out that γ-ray surveys are biased in the Northern Hemisphere whereas the recent IceCube data tentatively show a weak preference for the Southern Sky. Possible sub-dominant contributions from Galactic neutrino sources like remnants of supernovae and hypernovae are marginally consistent with present γ-ray limits. This emphasizes the importance of future diffuse TeV to PeV γ-ray surveys in the Southern Hemisphere, particularly in the extended region around the Galactic center including the Fermi Bubbles. © 2014 American Physical Society.


Grant
Agency: Department of Defense | Branch: Air Force | Program: STTR | Phase: Phase II | Award Amount: 750.00K | Year: 2014

ABSTRACT: ORBITEC will develop a new diagnostic to acquire simultaneous planes of velocity and temperature data at very high repetition rates. This diagnostic relies on a novel pulse burst laser system, a phosphor thermometry technique, and the mature PIV method. The work plan will involve developing and testing the laser, refining the integrated technique, and demonstrating it in a supersonic flow. The result will be a new diagnostic that will be very useful to the combustion community for generating temporally and spatially resolved data in reacting flow and for validating CFD models. The resulting products will have a promising market in both military and civilian applications. BENEFIT: This STTR program will produce several viable products: The PIV+T diagnostic, the pulse burst laser, the phosphor particles, and testing services. Because the PIV+T technique is designed for turbulent reacting flows, it will have applications in air-breathing engines, IC engines, and rocket engines. The markets include many branches of the military and many civilian companies.


Schedin P.,University of Colorado at Denver | Keely P.J.,University of Wisconsin - Madison
Cold Spring Harbor Perspectives in Biology | Year: 2011

Cells of the mammary gland are in intimate contact with other cells and with the extracellular matrix (ECM), both of which provide not only a biochemical context, but a mechanical context as well. Cell-mediated contraction allows cells to sense the stiffness of their microenvironment, and respond with appropriate mechanosignaling events that regulate gene expression and differentiation. ECM composition and organization are tightly regulated throughout development of the mammary gland, resulting in corresponding regulation of the mechanical environment and proper tissue architecture. Mechanical regulation is also at play during breast carcinoma progression, as changes in ECM deposition, composition, and organization accompany breast carcinoma. These changes result in stiffer matrices that activate mechanosignaling pathways and thereby induce cell proliferation, facilitate local tumor cell invasion, and promote progression. Thus, understanding the role of forces in the mammary gland is crucial to understanding both normal developmental and pathological processes. © 2011 Cold Spring Harbor Laboratory Press.


Ediger M.D.,University of Wisconsin - Madison | Forrest J.A.,University of Waterloo
Macromolecules | Year: 2014

The past 20 years have seen a substantial effort to understand dynamics and the glass transition in thin polymer films. In this Perspective, we consider developments in this field and offer a consistent interpretation of some major findings. We discuss recent experiments that directly measure mobility at or near the surface of glassy polymers. These experiments indicate that enhanced mobility near the free surface can exceed bulk mobility by several orders of magnitude and extend for several nanometers into the bulk polymer. Enhanced mobility near the free surface allows a qualitative understanding of many of the observations of a reduced glass transition temperature Tg in thin films. For thin films, knowledge of Tg by itself is less useful than for bulk materials. Because of this, new experimental methods that directly measure important material properties are being developed. © 2013 American Chemical Society.

Loading University of Wisconsin - Madison collaborators
Loading University of Wisconsin - Madison collaborators