202 research outputs found

    $p+^{4,6,8}He elastic scattering at intermediate energies

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    Using a relativistic nuclear optical potential consisting of a Lorentz scalar, VsV_{s}, and the time-like component of a four-vector potential, V0V_{0}, we calculate elastic scattering differential cross sections and polarizations for p+4p+^{4}He at intermediate energies for which experimental data are available. We also calculate the differential cross sections and analyzing powers for p+6,8p+^{6,8}He at intermediate energies and compare with the few available experimental data.Comment: 09 pages, 04 figure

    Ebola research funding: a systematic analysis, 1997–2015

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    Background: The latest outbreak of Ebola in West Africa overwhelmed the affected countries, with the impact on health extending far beyond Ebola–related deaths that have exceeded 11?000. The need to promptly mobilise resources to control emerging infections is widely recognized. Yet, data on research funding for emerging infections remains inadequately documented.Methods: We defined research investment as all funding flows for Ebola and/or Marburg virus from 1997 to April 2015 whose primary purpose was to advance knowledge and new technologies to prevent or cure disease. We sourced data directly from funding organizations and estimated the investment in 2015 US dollars (US).Results:FundingforEbolaandMarburgvirusresearchin1997to2015amountedtoUS).Results: Funding for Ebola and Marburg virus research in 1997 to 2015 amounted to US 1.035 billion, including US435.4million(42.0 435.4 million (42.0%) awarded in 2014 and 2015. Public sources of funding invested US 758.8 million (73.1%), philanthropic sources US65.1million(6.3 65.1 million (6.3%), and joint public/private/philanthropic ventures accounted for US 213.8 million (20.6%). Prior to the Ebola outbreak in 2014, pre–clinical research dominated research with US443.6million(73.9 443.6 million (73.9%) investment. After the outbreak, however, investment for new product development increased 942.7–fold and that for clinical trials rose 23.5–fold. Investment in new tools to control Ebola and Marburg virus amounted to US 399.1 million, with 61.3% awarded for vaccine research, 29.2% for novel therapeutics research such as antivirals and convalescent blood products, and 9.5% for diagnostics research. Research funding and bibliometric output were moderately associated (Spearman's ??=?0.5232, P?=?0.0259), however number of Ebola cases in previous outbreaks and research funding (??=?0.1706, P?=?0.4985) and Ebola cases in previous outbreaks and research output (??=?0.3020, P?=?0.0616) were poorly correlated.Conclusion: Significant public and philanthropic funds have been invested in Ebola and Marburg virus research in 2014 and 2015, following the outbreak in West Africa. Long term, strategic vision and leadership are needed to invest in infections with pandemic potential early, including innovative financing measures and open access investment data to promote the development of new therapies and technologies

    Non-Perturbative QCD Treatment of High-Energy Hadron-Hadron Scattering

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    Total cross-sections and logarithmic slopes of the elastic scattering cross-sections for different hadronic processes are calculated in the framework of the model of the stochastic vacuum. The relevant parameters of this model, a correlation length and the gluon condensate, are determined from scattering data, and found to be in very good agreement with values coming from completely different sources of information. A parameter-free relation is given between total cross-sections and slope parameters, which is shown to be remarkably valid up to the highest energies for which data exist.Comment: 60 pages, Heidelberg preprin

    Predictions of total and total reaction cross sections for nucleon-nucleus scattering up to 300 MeV

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    Total reaction cross sections are predicted for nucleons scattering from various nuclei. Projectile energies to 300 MeV are considered. So also are mass variations of those cross sections at selected energies. All predictions have been obtained from coordinate space optical potentials formed by full folding effective two-nucleon (NN) interactions with one body density matrix elements (OBDME) of the nuclear ground states. Good comparisons with data result when effective NN interactions defined by medium modification of free NN t matrices are used. Coupled with analyses of differential cross sections, these results are sensitive to details of the model ground states used to describe nuclei

    Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV

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    We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters

    Search for electroweak production of single top quarks in ppˉp\bar{p} collisions.

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    We present a search for electroweak production of single top quarks in the electron+jets and muon+jets decay channels. The measurements use ~90 pb^-1 of data from Run 1 of the Fermilab Tevatron collider, collected at 1.8 TeV with the DZero detector between 1992 and 1995. We use events that include a tagging muon, implying the presence of a b jet, to set an upper limit at the 95% confidence level on the cross section for the s-channel process ppbar->tb+X of 39 pb. The upper limit for the t-channel process ppbar->tqb+X is 58 pb. (arXiv

    InterMEL: An international biorepository and clinical database to uncover predictors of survival in early-stage melanoma

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    INTRODUCTION: We are conducting a multicenter study to identify classifiers predictive of disease-specific survival in patients with primary melanomas. Here we delineate the unique aspects, challenges, and best practices for optimizing a study of generally small-sized pigmented tumor samples including primary melanomas of at least 1.05mm from AJTCC TNM stage IIA-IIID patients. We also evaluated tissue-derived predictors of extracted nucleic acids' quality and success in downstream testing. This ongoing study will target 1,000 melanomas within the international InterMEL consortium. METHODS: Following a pre-established protocol, participating centers ship formalin-fixed paraffin embedded (FFPE) tissue sections to Memorial Sloan Kettering Cancer Center for the centralized handling, dermatopathology review and histology-guided coextraction of RNA and DNA. Samples are distributed for evaluation of somatic mutations using next gen sequencing (NGS) with the MSK-IMPACTTM assay, methylation-profiling (Infinium MethylationEPIC arrays), and miRNA expression (Nanostring nCounter Human v3 miRNA Expression Assay). RESULTS: Sufficient material was obtained for screening of miRNA expression in 683/685 (99%) eligible melanomas, methylation in 467 (68%), and somatic mutations in 560 (82%). In 446/685 (65%) cases, aliquots of RNA/DNA were sufficient for testing with all three platforms. Among samples evaluated by the time of this analysis, the mean NGS coverage was 249x, 59 (18.6%) samples had coverage below 100x, and 41/414 (10%) failed methylation QC due to low intensity probes or insufficient Meta-Mixed Interquartile (BMIQ)- and single sample (ss)- Noob normalizations. Six of 683 RNAs (1%) failed Nanostring QC due to the low proportion of probes above the minimum threshold. Age of the FFPE tissue blocks (p<0.001) and time elapsed from sectioning to co-extraction (p = 0.002) were associated with methylation screening failures. Melanin reduced the ability to amplify fragments of 200bp or greater (absent/lightly pigmented vs heavily pigmented, p<0.003). Conversely, heavily pigmented tumors rendered greater amounts of RNA (p<0.001), and of RNA above 200 nucleotides (p<0.001). CONCLUSION: Our experience with many archival tissues demonstrates that with careful management of tissue processing and quality control it is possible to conduct multi-omic studies in a complex multi-institutional setting for investigations involving minute quantities of FFPE tumors, as in studies of early-stage melanoma. The study describes, for the first time, the optimal strategy for obtaining archival and limited tumor tissue, the characteristics of the nucleic acids co-extracted from a unique cell lysate, and success rate in downstream applications. In addition, our findings provide an estimate of the anticipated attrition that will guide other large multicenter research and consortia
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