Zhang Z.,Cornell University |
Hayes A.G.,Cornell University |
Janssen M.A.,Jet Propulsion Laboratory |
Nicholson P.D.,Cornell University |
And 6 more authors.
Icarus | Year: 2017
Despite considerable study, Saturn's rings continue to challenge current theories for their provenance. Water ice comprises the bulk of Saturn's rings, yet it is the small fraction of non-icy material that is arguably more valuable in revealing clues about the system's origin and age. Herein, we present new measurements of the non-icy material fraction in Saturn's C ring, determined from microwave radiometry observations acquired by the Cassini spacecraft. Our observations show an exceptionally high brightness at near-zero azimuthal angles, suggesting a high porosity of 70–75% for the C ring particles. Furthermore, our results show that most regions in the C ring contain about 1–2% silicates. These results are consistent with an initially nearly pure-ice ring system that has been continuously contaminated by in-falling micrometeoroids over ∼15–90 million years, using the currently accepted value of the micrometeoroid flux at infinity of ∼4.5 × 10−17g cm−2 s−1, and assuming that the C ring optical depth and surface density has not changed significantly during that time. This absolute time scale is inversely proportional not only to the flux at infinity, but also to the amount of gravitational focusing by Saturn the micrometeoroids experience before encountering the rings. We also find an enhanced abundance of non-icy material concentrated in the middle C ring. When assumed to be mixed volumetrically (“intramixed”) with water ice, this enhanced contamination reaches a maximum concentration of 6–11% silicates by volume around a ring radius of 83,000 km, depending on the volume mixing model used. This is significantly higher than the inner and outer C ring. As opposed to an intramixing model, we also consider a silicate-core, icy-mantle model to address the fact that silicates may be present in chunks instead of fine powder in the ring particles. Such a model naturally helps to account for the observed opacity distribution. We propose several models to explain the radially varied non-icy material contamination. Our preferred model is that the C ring has been continuously polluted by meteoroid bombardment since it first formed, while the middle C ring was further contaminated by an incoming Centaur, a rocky object torn apart by tides and ultimately broken into pieces that currently reside in the middle C ring. If correct, the spatial extent of the enhanced non-icy material fraction suggests that the Centaur was likely to be captured and integrated into the rings perhaps as recently as ∼10–20 million years ago. © 2016 Elsevier Inc.
News Article | May 4, 2017
The latest upgrade to the football stadium at Sierra College is definitely generating some buzz around campus. Homer “Buzz” Ostrom Stadium now features a cutting edge field from AstroTurf®, which was installed in March. It’s an impressive playing surface, and one whose character is bolstered by what’s been done below the surface. The process of replacing Buzz Ostrom Stadium’s old artificial turf started underground. Valley Precision Grading, a certified AstroTurf distributor, began by remediating the underlayment with their specialized equipment. This process ensured proper drainage and level grading. That was followed by installation of a Brock Powerbase for maximum shock absorption. And finally the AstroTurf RootZone 3D3 Blend turf system was laid down. This is a high-end product that utilizes a specialized fiber blend for optimum performance, durability and game-day good looks. The signature touch for this customized playing surface at “The Buzz” is the use of green encapsulated rubber infill, which ensures a vibrant and clean surface over the life of the field. “We couldn’t be happier with the new turf installation at Buzz Ostrom Stadium,” said Lucas Moosman, Athletic Director at Sierra College. “It’s not just a replacement field, it’s a high performance upgrade that will give our student-athletes a great place to play for years to come.” With a combination of superior equipment and distinctive technique, VPG and AstroTurf are partnering to deliver unrivaled field replacement capabilities for Northern California. Some of their joint projects include the UC Berkley practice field and the revolutionary baseball field at Benedetti Diamond on the USF campus. Sierra College is a highly regarded junior college that boasts unparalleled success academically and athletically in the region. The Wolverine football team regularly plays in postseason bowl games, and the program has produced multiple All-Americans, dozens of transfers to Division I powerhouse schools, and even a few guys starring on Sundays in the NFL. About AstroTurf® For athletes and sport enthusiasts, AstroTurf® has redefined the way the game is played. The brand offers advanced, state-of-the-art, multi-sport and specialized synthetic turf systems with proprietary engineered technologies. A growing number of high schools, colleges, professional sports teams and municipalities continue to select AstroTurf-branded products for their premium quality, technical superiority, and safety. To learn more, visit AstroTurf’s newly redesigned website at http://www.astroturf.com.
Rudnick J.,University of California at Los Angeles |
Zandi R.,University of California at Riverside |
Shackell A.,University of California at Los Angeles |
Shackell A.,Sierra College |
Abraham D.,University of Oxford
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010
Finite-size effects in certain critical systems can be understood as universal Casimir forces. Here, we compare the Casimir force for free, fixed, periodic, and antiperiodic boundary conditions in the exactly calculable case of the ferromagnetic Ising model in one and two dimensions. We employ a procedure which allows us to calculate the Casimir force with the aforementioned boundary conditions analytically in a transparent manner. Among other results, we find an attractive Casimir force for the case of periodic boundary conditions and a repulsive Casimir force in the antiperiodic case. © 2010 The American Physical Society.
Place W.R.,University of California at Davis |
Place W.R.,Sierra College |
Bisson L.F.,University of California at Davis
American Journal of Enology and Viticulture | Year: 2013
In the YPH500 laboratory strain background of Saccharomyces cerevisiae, disruption of the SNF3 open reading frame results in the inability to grow at low glucose concentrations. Conversely, in haploid derivatives of wine strains and several other wild laboratory strains, deletion of SNF3 does not lead to a discernable phenotype. Complementation and subsequent tetrad analysis demonstrated that the snf3 suppressor found in wine strains is a dominant gene encoded by a single locus, not allelic to the known dominant suppressor, RGT2-1. HXT7 was identified independently from two low-copy number genomic libraries of strains carrying the novel dominant suppressor as capable of suppressing the snf3Δ phenotype in YPH500. Cloned HXT7 plus 1 kb of promoter was sufficient for suppression. Sequence comparison of HXT7 from the YPH500 background to that of the archetype lab strain, S288C, demonstrated that YPH500-derived strains contain a chimera of the HXT6 promoter and the HXT7 gene (HXT6P/7). Deletion of HXT7 in S288C results in expression of the snf3 phenotype in this genetic background, while deletion of HXT6 only slightly diminishes growth in the snf3 HXT7 strain. In contrast to cloned HXT7, expression of HXT6P/7 cloned in a centromere (CEN)-based plasmid is not sufficient for snf3 suppression. A construct placing HXT6 under the control of the HXT7 promoter also suppresses the snf3 growth defect. Suppression of snf3 in the wine and wild strains of Saccharomyces evaluated is therefore due to the pattern of expression of the Hxt7 protein rather than to differences in the HXT7 and HXT6 coding sequences. © 2013 by the American Society for Enology and Viticulture. All rights reserved.
News Article | November 21, 2016
An analysis of California’s college career training programs by leading higher education resource site, Community for Accredited Online Schools (AccreditedSchoolsOnline.org), has revealed the top 54 schools in the state for trade and vocational education. Crediting two-year and four-year schools respectively, the site ranked Lincoln University, Humphreys College Stockton and Modesto Campuses, University of LaVerne, American River College, Sacramento City College, College of the Sequoias, Cosumnes River College and Cerritos College among the top scoring for Best Schools for Trade & Vocational Programs in California for 2016-2017. “Some of today’s fastest growing industries are in trade and vocational fields, and projections show these industries continuing to gain steam over the next decade,” said Doug Jones, CEO and Founder of the Community for Accredited Online Schools. “The California colleges credited on our list are those helping students achieve maximum success with not only high quality training, but career placement and counseling services that can pave the way to successful job placement.” The Community for Accredited Online Schools requires colleges and universities to meet minimum standards to qualify for ranking. Institutions must be regionally accredited and hold public or private not-for-profit status to be considered. For the Best Trade & Vocational Programs list, schools must also offer career counseling and placement services to assist students. Qualifying schools are scored and ranked based on analysis of more than a dozen unique statistics, such as student-teacher ratios and program variety. A full list of schools on California’s ranking, as well as details on the data points and methodology used to determine scores and list position can be found at: Allan Hancock College American River College Antelope Valley College Bakersfield College Cabrillo College California College San Diego, San Diego California College San Diego, San Marcos Cerritos College Cerro Coso Community College Chabot College Chaffey College Citrus College City College of San Francisco Coastline Community College College of Alameda College of San Mateo College of the Canyons College of the Desert College of the Redwoods College of the Sequoias Contra Costa College Cosumnes River College Crafton Hills College Cuyamaca College De Anza College Diablo Valley College East Los Angeles College El Camino College Folsom Lake College Foothill College Fresno City College Fullerton College Glendale Community College Golden West College Grossmont College Humphreys College - Stockton & Modesto Campuses Imperial Valley College Irvine Valley College Lake Tahoe Community College Laney College Las Positas College Lassen Community College Lincoln University Long Beach City College Los Angeles City College Los Angeles Harbor College Los Angeles Mission College Los Angeles Pierce College Los Angeles Southwest College Los Angeles Trade Technical College Los Angeles Valley College Los Medanos College Merced College Mission College Monterey Peninsula College Moorpark College Moreno Valley College Mt. San Antonio College Napa Valley College Norco College Ohlone College Orange Coast College Oxnard College Pasadena City College Porterville College Reedley College Rio Hondo College Riverside City College Sacramento City College Saddleback College San Bernardino Valley College San Diego City College San Diego Mesa College San Diego Miramar College San Jose City College Santa Barbara City College Santa Monica College Santa Rosa Junior College Shasta College Sierra College Skyline College Solano Community College Taft College University of La Verne Ventura College Victor Valley College West Los Angeles College Yuba College About Us: The Community for Accredited Online Schools (AccreditedSchoolsOnline.org) was founded in 2011 to provide students and parents with quality data and information about pursuing an affordable education that has been certified by an accrediting agency. Our community resource materials and tools span topics such as college accreditation, financial aid, opportunities available to veterans, people with disabilities, as well as online learning resources. We feature higher education institutions that have developed online learning programs that include highly trained faculty, new technology and resources, and online support services to help students achieve educational success. environments that include highly trained faculty, new technology and resources, and online support services to help students achieve educational and career success.
de Pater I.,University of California at Berkeley |
de Pater I.,Technical University of Delft |
de Pater I.,SRON Netherlands Institute for Space Research |
Dunn D.E.,University of California at Berkeley |
And 11 more authors.
Icarus | Year: 2013
We present observations of the uranian ring system at a wavelength of 2.2μm, taken between 2003 and 2008 with NIRC2 on the W.M. Keck telescope in Hawaii, and on 15-17 August 2007 with NaCo on the Very Large Telescope (VLT) in Chile. Of particular interest are the data taken around the time of the uranian ring plane crossing with Earth on 16 August 2007, and with the Sun (equinox) on 7 December 2007. We model the data at the different viewing aspects with a Monte Carlo model to determine: (1) the normal optical depth τ0, the location, and the radial extent of the main rings, and (2) the parameter Aτ0 (A is the particle geometric albedo), the location, and the radial plus vertical extent of the dusty rings. Our main conclusions are: (i) The brightness of the ring is significantly enhanced at small phase and ring inclination angles; we suggest this extreme opposition effect to probably be dominated by a reduction in interparticle shadowing. (ii) A broad sheet of dust particles extends inwards from the λ ring almost to the planet itself. This dust sheet has a vertical extent of ~140km, and Aτ0=2.2×10-6. (iii) The dusty rings between ring 4 and the α ring and between the α and β rings are vertically extended with a thickness of ~300km. (iv) The ring extends from ~41,350km almost all the way inwards to the planet. The main ring, centered at ~39,500km from the planet, is characterized by Aτ0=3.7×10-6; this parameter decreases closer to the planet. The ring has a full vertical extent of order 800-900km, with a pronounced density enhancement in the mid-plane. (v) The c ring is optically thin and less than several tens of km in the vertical direction. This ring may be composed of macroscopic material, surrounded by clumps of dust. © 2013 Elsevier Inc.
News Article | October 29, 2016
In celebration of National Manufacturing Day, on October 7, 2016, Sierra College, SME Sacramento Valley and Hacker Lab are kicking off new SME Manufacturing Advice Office Hours. SME volunteers will offer advice on design, engineering and manufacturing twice per month. Drop in hours are between 10-11am on the first Monday of the month (Oct. 3) at Hacker Lab Powered by Sierra College, 4804 Granite Dr., in Rocklin. On the third Monday of the month, (Oct. 17) open office hours will be held 10-11am at Hacker Lab in Midtown at 1715 I St, Sacramento. SME volunteers with expertise in mechanical and manufacturing engineering and product life cycle development will staff the office hours, explained Jeff Briggs, President, SME Sacramento Valley. “Entrepreneurs may request a product design review or ask for help making a 3D printed prototype,” said Briggs. Additionally, Hacker Lab offers classes on design and 3D printing. There are several 3D printers at both the Rocklin and Sacramento Hacker Lab locations supplied by Sierra College Center for Applied Competitive Technologies (CACT) to support inventors in producing prototypes. According to Briggs, manufacturing firms may be interested in gaining a fresh perspective to overcome a challenge or improve existing processes. “The SME members will also be able to give advice on materials sourcing and locating manufacturers to produce products,” said Briggs. “The Hacker Lab community is about sharing ideas, connecting people, and celebrating successes in developing new products that can make the world a better place. It is the perfect place for SME to help people with manufacturing issues.” The Sierra College Center for Applied Competitive Technologies (CACT) assists manufacturers throughout the region with training and technical support, explained Carol Pepper-Kittredge, CACT Director, Sierra College. “This partnership with SME and Hacker Lab will give more companies access to local experts and that will drive more manufacturing in this region,” said Pepper-Kittredge. SME Sacramento Valley has arranged several manufacturing tours in the greater Sacramento region held in celebration of Manufacturing Month, according to Pepper-Kittredge. “These tours enable businesses to learn from each other,” said Pepper-Kittredge. “When students attend, it makes them aware of the exciting, well paid careers right here in Northern California. The experience of talking with employers encourages students to continue studying design, engineering, mechatronics, welding and construction at college.” Briggs indicated that the following tour dates are planned: Oct. 4 at Ceronix in Auburn, Transfer Flow Inc. on Oct. 7 in Chico, Sierra Pacific Industries on Oct. 11 in Lincoln, Ruff Stuff Specialties on Oct. 18 in Loomis and RobbJack on Oct. 25 in Lincoln. Learn more about the tours at the SME Sacramento Valley website. The City of Rocklin is also holding a Rocklin Mini Maker Faire® to be held at the Sierra College campus in Rocklin on October 1 from 10 am to 5 pm. In 2015, over 7000 people attended this event and experienced the joy of making, observed Pepper-Kittredge. “Participants can meet other makers of all ages, experience new technology, produce fun projects, make crafts, try science experiments, see amazing inventions and make their own discoveries,” said Pepper-Kittredge. “Creative, hands-on experiences are often breakthroughs for people who discover a passion; these are future designers, engineers and manufacturers.” About Sierra College CACT Sierra College Center for Applied Competitive Technologies (CACT) is focused on Advanced Manufacturing and is funded through the Workforce and Economic Development program of the California Community College Chancellor’s Office. Since 1992, the Sierra College CACT has provided customized training in lean, process improvement, zero waste, supervision, workplace software, communication and many other topics for organizations, manufacturers and technology companies throughout Northern California. For more information, go to http://www.sierracollegetraining.com. About Sierra College Since its founding in 1936, Sierra College has focused on quality instruction and meeting the needs of the communities that it serves. With approximately 125 degree and certificate programs, Sierra College is ranked first in Northern California for transfers to 4 year Universities, offers career/technical training, and classes for upgrading job skills. Sierra graduates can be found in businesses and industries throughout the region. Our award-winning faculty members enhance their teaching with research, authorship and industry expertise. We are also recognized nationally for excellence in our athletic programs.
Discovery of a novel anticancer agent with both anti-topoisomerase I and II activities in hepatocellular carcinoma SK-Hep-1 cells in vitro and in vivo: Cinnamomum verum component 2-methoxycinnamaldehyde
PubMed | Sierra College, Antai Tian Sheng Memorial Hospital, Lotung Poh Ai Hospital, Medical University of Lublin and 2 more.
Type: | Journal: Drug design, development and therapy | Year: 2016
Cinnamomum verum is used to make the spice cinnamon and has been used as a traditional Chinese herbal medicine for various applications. We evaluated the anticancer effect of 2-methoxycinnamaldehyde (2-MCA), a constituent of the bark of the plant, and its underlying molecular biomarkers associated with carcinogenesis in human hepatocellular carcinoma SK-Hep-1 cell line. The results show that 2-MCA suppressed proliferation and induced apoptosis as indicated by mitochondrial membrane potential loss, activation of caspase-3 and caspase-9, increase in the DNA content in sub-G1, and morphological characteristics of apoptosis, including blebbing of plasma membrane, nuclear condensation, fragmentation, apoptotic body formation, and long comet tail. In addition, 2-MCA also induced lysosomal vacuolation with increased volume of acidic compartments, suppressions of nuclear transcription factors NF-B, cyclooxygenase-2, prostaglandin E2 (PGE2), and both topoisomerase I and II activities in a dose-dependent manner. Further study reveals the growth-inhibitory effect of 2-MCA was also evident in a nude mice model. Taken together, the data suggest that the growth-inhibitory effect of 2-MCA against SK-Hep-1 cells is accompanied by downregulations of NF-B-binding activity, inflammatory responses involving cyclooxygenase-2 and PGE2, and proliferative control involving apoptosis, both topoisomerase I and II activities, together with an upregulation of lysosomal vacuolation and volume of acidic compartments. Similar effects (including all of the above-mentioned effects) were found in other tested cell lines, including human hepatocellular carcinoma Hep 3B, lung adenocarcinoma A549, squamous cell carcinoma NCI-H520, colorectal adenocarcinoma COLO 205, and T-lymphoblastic MOLT-3 (results not shown). Our data suggest that 2-MCA could be a potential agent for anticancer therapy.
Mooi R.,California Academy of Sciences |
Hilton R.P.,Sierra College
Journal of Paleontology | Year: 2014
Although diadematacean sea urchins (diadematids, aspidodiadematids, and micropygids) likely diverged sometime during the Jurassic, the lack of fossils representing this group has greatly hampered progress in understanding their evolution. No unequivocal Jurassic diademataceans have been described previously from North America. We describe a new genus and species, Sierradiadema kristini, from a single fossil from the Middle Jurassic (Callovian) Colfax sequence of the Mariposa Formation exposed in the Middle Fork American River drainage of the northern Sierra Nevada, California. The specimen, although not complete, reveals details of the spination and tooth morphology often lacking in Jurassic diademataceans, along with test architecture that yields information concerning the relative timing of important events in the origins of the diadematids in particular. We explore this evolution with a phylogenetic analysis of relevant clades with Jurassic times of divergence, finding not only that Sierradiadema n. gen. is the earliest known member of a clade containing the extant Diadematidae, but that it will stimulate ongoing discussion of the putative Jurassic origins of all the diadematacean groups. © 2014, The Paleontological Society.
Dunn D.E.,Sierra College |
Dunn D.E.,University of California at Berkeley |
de Pater I.,University of California at Berkeley |
Stam D.,SRON Netherlands Institute for Space Research
Icarus | Year: 2010
We present a Monte Carlo model of the uranian rings, and compare this model to images of the system obtained with the Keck adaptive optics system in July 2004, at a wavelength of 2.2μm (from de Pater et al. (de Pater, I., Gibbard, S.G., Hammel, H.B. [2006a]. Icarus 180, 186-200)). We confirm the presence of the ζ ring, but show that this ring must extend inwards much further than previously thought, although with an optical depth much lower than that in the main ζ ring component. We further confirm dust rings between rings α-4 and β-α, as well as near the λ ring. In addition, we show that a broad sheet of faint material (τ 0∼10 -3) must be present through most of the ring region, from the α ring through the λ ring. © 2010.