312 research outputs found

    Generalized Interpolation Material Point Approach to High Melting Explosive with Cavities Under Shock

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    Criterion for contacting is critically important for the Generalized Interpolation Material Point(GIMP) method. We present an improved criterion by adding a switching function. With the method dynamical response of high melting explosive(HMX) with cavities under shock is investigated. The physical model used in the present work is an elastic-to-plastic and thermal-dynamical model with Mie-Gr\"uneissen equation of state. We mainly concern the influence of various parameters, including the impacting velocity vv, cavity size RR, etc, to the dynamical and thermodynamical behaviors of the material. For the colliding of two bodies with a cavity in each, a secondary impacting is observed. Correspondingly, the separation distance DD of the two bodies has a maximum value DmaxD_{\max} in between the initial and second impacts. When the initial impacting velocity vv is not large enough, the cavity collapses in a nearly symmetric fashion, the maximum separation distance DmaxD_{\max} increases with vv. When the initial shock wave is strong enough to collapse the cavity asymmetrically along the shock direction, the variation of DmaxD_{\max} with vv does not show monotonic behavior. Our numerical results show clear indication that the existence of cavities in explosive helps the creation of ``hot spots''.Comment: Figs.2,4,7,11 in JPG format; Accepted for publication in J. Phys. D: Applied Physic

    Three serendipitous pathways in E. coli can bypass a block in pyridoxal-5′-phosphate synthesis

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    Overexpression of seven different genes restores growth of a ΔpdxB strain of E. coli, which cannot make pyridoxal phosphate (PLP), on M9/glucose.None of the enzymes encoded by these genes has a promiscuous 4-phosphoerythronate dehydrogenase activity that can replace the activity of PdxB.Overexpression of these genes restores PLP synthesis by three different serendipitous pathways that feed into the normal PLP synthesis pathway downstream of the blocked step.Reactions in one of these pathways are catalyzed by low-level activities of enzymes of unknown function and a promiscuous activity of an enzyme that normally has a role in another pathway; one reaction appears to be non-enzymatic

    Ursinus College Alumni Journal, March 1963

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    The President writes • Dr. McClure\u27s charge to graduating classes • Norman Egbert McClure: A tribute • Faculty memorial minute • Alumni memorial minute • Twenty-five years of the Messiah at Ursinus • As I recall • A gift for the First Lady • Philip L. Corson • Gypsy: Hail and farewell • Controversy at midnight • Two students leave for Peace Corps • Capital funds subscription total $467,392 to date • Capital funds • McClure and Bone memorials • The Century Club • Dining hall news • Mid-year report of 1963 Loyalty Fund campaign • The third alumni seminar • Clawson to be honored • Reimert recognized • Paisley elected college treasurer • Travel seminar • Navy V-12 reunion planned • Church headquarters at Ursinus • You and the future of Ursinus • College costs • Alumni album • Franklin Earnest III, \u2739 • Walter F. Longacre, \u2714 • Lyndell R. Reber, \u2736 • Archer P. Crosley, \u2742 • Robert S. Litwak, \u2745 • Michael R. Deitz, \u2754 • Allan Lake Rice • Dean concludes career • Wrestling • Dryfoos the greatest • Nominees for Alumni Association offices • Class notes • Weddings • Births • Necrology • Regionalshttps://digitalcommons.ursinus.edu/alumnijournal/1076/thumbnail.jp

    The distribution of pond snail communities across a landscape: separating out the influence of spatial position from local habitat quality for ponds in south-east Northumberland, UK

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    Ponds support a rich biodiversity because the heterogeneity of individual ponds creates, at the landscape scale, a diversity of habitats for wildlife. The distribution of pond animals and plants will be influenced by both the local conditions within a pond and the spatial distribution of ponds across the landscape. Separating out the local from the spatial is difficult because the two are often linked. Pond snails are likely to be affected by both local conditions, e.g. water hardness, and spatial patterns, e.g. distance between ponds, but studies of snail communities struggle distinguishing between the two. In this study, communities of snails were recorded from 52 ponds in a biogeographically coherent landscape in north-east England. The distribution of snail communities was compared to local environments characterised by the macrophyte communities within each pond and to the spatial pattern of ponds throughout the landscape. Mantel tests were used to partial out the local versus the landscape respective influences. Snail communities became more similar in ponds that were closer together and in ponds with similar macrophyte communities as both the local and the landscape scale were important for this group of animals. Data were collected from several types of ponds, including those created on nature reserves specifically for wildlife, old field ponds (at least 150 years old) primarily created for watering livestock and subsidence ponds outside protected areas or amongst coastal dunes. No one pond type supported all the species. Larger, deeper ponds on nature reserves had the highest numbers of species within individual ponds but shallow, temporary sites on farm land supported a distinct temporary water fauna. The conservation of pond snails in this region requires a diversity of pond types rather than one idealised type and ponds scattered throughout the area at a variety of sites, not just concentrated on nature reserves

    The Non-Uniform Distribution of Galaxies from Data of the SDSS DR7 Survey

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    We have analyzed the spatial distribution of galaxies from the release of the Sloan Digital Sky Survey of galactic redshifts (SDSS DR7), applying the complete correlation function (conditional density), two-point conditional density (cylinder), and radial density methods. Our analysis demonstrates that the conditional density has a power-law form for scales lengths 0.5-30 Mpc/h, with the power-law corresponding to the fractal dimension D = 2.2+-0.2; for scale lengths in excess of 30 Mpc/h, it enters an essentially flat regime, as is expected for a uniform distribution of galaxies. However, in the analysis applying the cylinder method, the power-law character with D = 2.0+-0.3 persists to scale lengths of 70 Mpc/h. The radial density method reveals inhomogeneities in the spatial distribution of galaxies on scales of 200 Mpc/h with a density contrast of two, confirming that translation invariance is violated in the distribution of galaxies to 300 Mpc/h, with the sampling depth of the SDSS galaxies being 600 Mpc/h.Comment: 22 page

    Cross-site comparison of ribosomal depletion kits for Illumina RNAseq library construction

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    Background Ribosomal RNA (rRNA) comprises at least 90% of total RNA extracted from mammalian tissue or cell line samples. Informative transcriptional profiling using massively parallel sequencing technologies requires either enrichment of mature poly-adenylated transcripts or targeted depletion of the rRNA fraction. The latter method is of particular interest because it is compatible with degraded samples such as those extracted from FFPE and also captures transcripts that are not poly-adenylated such as some non-coding RNAs. Here we provide a cross-site study that evaluates the performance of ribosomal RNA removal kits from Illumina, Takara/Clontech, Kapa Biosystems, Lexogen, New England Biolabs and Qiagen on intact and degraded RNA samples. Results We find that all of the kits are capable of performing significant ribosomal depletion, though there are differences in their ease of use. All kits were able to remove ribosomal RNA to below 20% with intact RNA and identify ~ 14,000 protein coding genes from the Universal Human Reference RNA sample at >1FPKM. Analysis of differentially detected genes between kits suggests that transcript length may be a key factor in library production efficiency. Conclusions These results provide a roadmap for labs on the strengths of each of these methods and how best to utilize them. Keywords: RNAseqr; RNA depletion; Illumina; NGS; ABRF; TranscriptomicsNational Cancer Institute (U.S.) (Grant P30-CA14051)National Institute of Environmental Health Sciences (Grant P30-ES002109

    The Grizzly, October 1, 1991

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    Whittaker Relates Gulf Experience • Sorority Pledging Underway • U.S.E.A.C. Conference a Success • Ursinus Students Feel the Excitement of Habitat • College Tutorial Project Thrives • U.C. Welcomes New Instructors • Leadershop 1991 • U.S.G.A. Finds a Home • A Plea for Help • GN\u27R: Illusion ... of Good Music • State Museum Exhibits Berman Sculptures • Jane Ira Bloom Jazzes It Up • Sky Sands Strikes Ursinus • Aerobics Attack • The Tempting Temple • Field Hockey Faces Tough Times • Bears Terrorized by Western Maryland • Lady Bears Finish 4th • Bears Tee Off • Runners Get Recognition • Soccer Splits Two • Cross Country Cruises to 3rd Place • Gift to Give • Alcohol Policy Enforcement Tightens • Intellect Over Image • Wismer Whine • Healing the Wounds of the Gulf War • The Search For the Chemical Promisehttps://digitalcommons.ursinus.edu/grizzlynews/1278/thumbnail.jp
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