52 research outputs found
Comment on "Typicality for Generalized Microcanonical Ensemble"
The validity of the so-called "typicality" argument for a generalised
microcanonical ensemble proposed recently is examined.Comment: Version to appear in PR
Comparisons of Concordance in Additive Models
In this note we compare bivariate additive models with respect to their Pearson correlation coecients, Kendall's concordance coecients, and Blomqvist medial correlation coefcients. The conditions that enable the comparisons involve variability stochastic orders such as the dispersive and the peakedness orders. Specically we show that we can compare the Kendall's concordance coecients of Cheriyan and Ramabhadran's bivariate gamma distributions, in spite of the fact that it is hard (and not necessary) to compute the
Construction of asymmetric copulas and its application in two-dimensional reliability modelling
Copulas offer a useful tool in modelling the dependence among random variables. In the literature, most of the existing copulas are symmetric while data collected from the real world may exhibit asymmetric nature. This necessitates developing asymmetric copulas that can model such data. In the meantime, existing methods of modelling two-dimensional reliability data are not able to capture the tail dependence that exists between the pair of age and usage, which are the two dimensions designated to describe product life. This paper proposes two new methods of constructing asymmetric copulas, discusses the properties of the new copulas, and applies the method to fit two-dimensional reliability data that are collected from the real world
Loss of DNA ligase IV prevents recognition of DNA by double-strand break repair proteins XRCC4 and XLF
The repair of DNA double-strand breaks by nonhomologous end-joining (NHEJ) is essential for maintenance of genomic integrity and cell viability. Central to the molecular mechanism of NHEJ is DNA ligase IV/XRCC4/XLF complex, which rejoins the DNA. During adenovirus (Ad5) infection, ligase IV is targeted for degradation in a process that requires expression of the viral E1B 55k and E4 34k proteins while XRCC4 and XLF protein levels remain unchanged. We show that in Ad5-infected cells, loss of ligase IV is accompanied by loss of DNA binding by XRCC4. Expression of E1B 55k and E4 34k was sufficient to cause loss of ligase IV and loss of XRCC4 DNA binding. Using ligase IV mutant human cell lines, we determined that the absence of ligase IV, and not expression of viral proteins, coincided with inhibition of DNA binding by XRCC4. In ligase IV mutant human cell lines, DNA binding by XLF was also inhibited. Expression of both wild-type and adenylation-mutant ligase IV in ligase IV-deficient cells restored DNA binding by XRCC4. These data suggest that the intrinsic DNA-binding activities of XRCC4 and XLF may be subject to regulation and are down regulated in human cells that lack ligase IV
HP1α recruitment to DNA damage by p150CAF-1 promotes homologous recombination repair
p150CAF-1-mediated recruitment of HP1α to DNA is essential for efficient assembly of DNA damage response complexes and subsequent homologous recombination repair
On distributions of order statistics for absolutely continuous copulas with applications to reliability
summary:Performance of coherent reliability systems is strongly connected with distributions of order statistics of failure times of components. A crucial assumption here is that the distributions of possibly mutually dependent lifetimes of components are exchangeable and jointly absolutely continuous. Assuming absolute continuity of marginals, we focus on properties of respective copulas and characterize the marginal distribution functions of order statistics that may correspond to absolute continuous and possibly exchangeable copulas. One characterization is based on the vector of distribution functions of all order statistics, and the other concerns the distribution of a single order statistic
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