1,974 research outputs found

    Adjusted Hazard Rate Estimator Based on a Known Censoring Probability

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    Cataloged from PDF version of article.In most reliability studies involving censoring, one assumes that censoring probabilities are unknown. We derive a nonparametric estimator for the survival function when information regarding censoring frequency is available. The estimator is constructed by adjusting the Nelson–Aalen estimator to incorporate censoring information. Our results indicate significant improvements can be achieved if available information regarding censoring is used. We compare this model to the Koziol–Green model, which is also based on a form of proportional hazards for the lifetime and censoring distributions. Two examples of survival data help to illustrate the differences in the estimation techniques

    Adjusted hazard rate estimator based on a known censoring probability

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    In most reliability studies involving censoring, one assumes that censoring probabilities are unknown. We derive a nonparametric estimator for the survival function when information regarding censoring frequency is available. The estimator is constructed by adjusting the Nelson-Aalen estimator to incorporate censoring information. Our results indicate significant improvements can be achieved if available information regarding censoring is used. We compare this model to the Koziol-Green model, which is also based on a form of proportional hazards for the lifetime and censoring distributions. Two examples of survival data help to illustrate the differences in the estimation techniques. © 2011 Copyright Taylor and Francis Group, LLC

    Pore Shape Modification of a Microporous Metal-Organic Framework Using High Pressure:Accessing a New Phase with Oversized Guest Molecules

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    The authors thank the Royal Society of Edinburgh and the Scottish Government for a fellowship to S.A.M. The authors thank EPSRC (EP/J02077X/1) and Leverhulme Trust for a research project grant (RPG-209) for financial support. They also thank the UK Carr Parinello consortium for allocation of computing time on the EPSRC high performance computing resource ARCHER (managed by the Edinburgh Parallel Computing Centre, the EaSTCHEM Research Computing Facility and the University of Edinburgh ECDF facility).Pressures up to 0.8 GPa have been used to squeeze a range of sterically "oversized" C5-C8 alkane guest molecules into the cavities of a small-pore Sc-based metal?organic framework. Guest inclusion causes a pronounced reorientation of the aromatic rings of one-third of the terephthalate linkers, which act as "torsion springs", resulting in a fully reversible change in the local pore structure. The study demonstrates how pressure-induced guest uptake can be used to investigate framework flexibility relevant to "breathing" behavior and to understand the uptake of guest molecules in MOFs relevant to hydrocarbon separation.PostprintPeer reviewe

    Infection-Associated Nuclear Degeneration in the Rice Blast Fungus Magnaporthe oryzae Requires Non-Selective Macro-Autophagy

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    addresses: School of Biosciences, University of Exeter, Exeter, Devon, United Kingdom.notes: PMCID: PMC3308974Freely-available open access article.The rice blast fungus Magnaporthe oryzae elaborates a specialized infection structure called an appressorium to breach the rice leaf surface and gain access to plant tissue. Appressorium development is controlled by cell cycle progression, and a single round of nuclear division occurs prior to appressorium formation. Mitosis is always followed by programmed cell death of the spore from which the appressorium develops. Nuclear degeneration in the spore is known to be essential for plant infection, but the precise mechanism by which it occurs is not known

    A Late Form of Nucleophagy in Saccharomyces cerevisiae

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    Autophagy encompasses several processes by which cytosol and organelles can be delivered to the vacuole/lysosome for breakdown and recycling. We sought to investigate autophagy of the nucleus (nucleophagy) in the yeast Saccharomyces cerevisiae by employing genetically encoded fluorescent reporters. The use of such a nuclear reporter, n-Rosella, proved the basis of robust assays based on either following its accumulation (by confocal microscopy), or degradation (by immunoblotting), within the vacuole. We observed the delivery of n-Rosella to the vacuole only after prolonged periods of nitrogen starvation. Dual labeling of cells with Nvj1p-EYFP, a nuclear membrane reporter of piecemeal micronucleophagy of the nucleus (PMN), and the nucleoplasm-targeted NAB35-DsRed.T3 allowed us to detect PMN soon after the commencement of nitrogen starvation whilst delivery to the vacuole of the nucleoplasm reporter was observed only after prolonged periods of nitrogen starvation. This later delivery of nuclear components to the vacuole has been designated LN (late nucleophagy). Only a very few cells showed simultaneous accumulation of both reporters (Nvj1p-EYFP and NAB35-DsRed.T3) in the vacuole. We determined, therefore, that delivery of the two respective nuclear reporters to the vacuole is temporally and spatially separated. Furthermore, our data suggest that LN is mechanistically distinct from PMN because it can occur in nvj1Δ and vac8Δ cells, and does not require ATG11. Nevertheless, a subset of the components of the core macroautophagic machinery is required for LN as it is efficiently inhibited in null mutants of several autophagy-related genes (ATG) specifying such components. Moreover, the inhibition of LN in some mutants is accompanied by alterations in nuclear morphology

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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