14,094 research outputs found

    Some Implications of inverse-Compton Scattering of Hot Cocoon Radiation by relativistic jets in Gamma-Ray Bursts

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    Long Gamma-Ray Bursts (GRB) relativistic jets are surrounded by hot cocoons which confine jets during their punch out from the progenitor star. These cocoons are copious sources of X-ray photons that can be and are inverse-Compton (IC) scattered to MeV--GeV energies by electrons in the relativistic jet. We provide detailed estimates for IC flux resulting from various interactions between X-ray photons and the relativistic jet, and describe what we can learn about GRB jets and progenitor stars from the detection (or an upper limit) of these IC scattered photons.Comment: 26 pages 7 figures (comments most welcome

    Fire and heat resistant laminating resins based on maleimido substituted aromatic cyclotriphosphazene polymer

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    4-Aminophenoxy cyclotriphosphazenes are reacted with maleic anhydride to produce maleamic acids which are converted to the maleimides. The maleimides are polymerized. By selection of starting materials (e.g., hexakis amino or trisaminophenoxy trisphenoxy cyclotriphosphazenes), selection of molar proportions of reactants, use of mixtures of anhydrides and use of dianhydrides as bridging groups a variety of maleimides and polymers are produced. The polymers have high limiting oxygen indices, high char yields and other useful heat and fire resistant properties making them useful as, for example, impregnants of fabrics

    Aminophenoxycyclotriphosphazene cured epoxy resins and the composites, laminates, adhesives and structures thereof

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    Aminophenoxy cyclotriphosphazenes such as hexakis (4-aminophenoxy) cyclotriphosphazene and tris (4-aminophenoxy)-tris phenoxy cyclotriphosphazene are used as curing agents for epoxy resins. These 1,2-epoxy resins are selected from di- or polyepoxide containing organic moieties of the formula (CH2-CHO-CH2) m-W-R-W- (CH2CH-CH2O)m where R is diphenyl dimethylmethane, diphenylmethane; W is a nitrogen or oxygen atom; and m is 1 when W is oxygen and 2 when W is nitrogen. The resins are cured thermally in stages at between about 110 to 135 C for between about 1 and 10 min, then at between about 175 to 185 C for between 0.5 to 10 hr and post cured at between about 215 and 235 C for between 0.1 and 2 hr. These resins are useful for making fire resistant elevated temperature stable composites, laminates, molded parts, and adhesives and structures, usually for aircraft secondary structures and for spacecraft construction

    Incentive Mechanisms for Hierarchical Spectrum Markets

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    In this paper, we study spectrum allocation mechanisms in hierarchical multi-layer markets which are expected to proliferate in the near future based on the current spectrum policy reform proposals. We consider a setting where a state agency sells spectrum channels to Primary Operators (POs) who subsequently resell them to Secondary Operators (SOs) through auctions. We show that these hierarchical markets do not result in a socially efficient spectrum allocation which is aimed by the agency, due to lack of coordination among the entities in different layers and the inherently selfish revenue-maximizing strategy of POs. In order to reconcile these opposing objectives, we propose an incentive mechanism which aligns the strategy and the actions of the POs with the objective of the agency, and thus leads to system performance improvement in terms of social welfare. This pricing-based scheme constitutes a method for hierarchical market regulation. A basic component of the proposed incentive mechanism is a novel auction scheme which enables POs to allocate their spectrum by balancing their derived revenue and the welfare of the SOs.Comment: 9 page

    iSeqQC: a tool for expression-based quality control in RNA sequencing.

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    BACKGROUND: Quality Control in any high-throughput sequencing technology is a critical step, which if overlooked can compromise an experiment and the resulting conclusions. A number of methods exist to identify biases during sequencing or alignment, yet not many tools exist to interpret biases due to outliers. RESULTS: Hence, we developed iSeqQC, an expression-based QC tool that detects outliers either produced due to variable laboratory conditions or due to dissimilarity within a phenotypic group. iSeqQC implements various statistical approaches including unsupervised clustering, agglomerative hierarchical clustering and correlation coefficients to provide insight into outliers. It can be utilized through command-line (Github: https://github.com/gkumar09/iSeqQC) or web-interface (http://cancerwebpa.jefferson.edu/iSeqQC). A local shiny installation can also be obtained from github (https://github.com/gkumar09/iSeqQC). CONCLUSION: iSeqQC is a fast, light-weight, expression-based QC tool that detects outliers by implementing various statistical approaches
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