55,847 research outputs found
Event History Analysis of Dynamic Communication Networks
Statistical analysis on networks has received growing attention due to demand
from various emerging applications. In dynamic networks, one of the key
interests is to model the event history of time-stamped interactions amongst
nodes. We propose to model dynamic directed communication networks via
multivariate counting processes. A pseudo partial likelihood approach is
exploited to capture the network dependence structure. Asymptotic results of
the resulting estimation are established. Numerical results are performed to
demonstrate effectiveness of our proposal
Detecting differential usage of exons from RNA-Seq data
RNA-Seq is a powerful tool for the study of alternative splicing and other forms of alternative isoform expression. Understanding the regulation of these processes requires comparisons between treatments, tissues or conditions. For the analysis of such experiments, we present _DEXSeq_, a statistical method to test for differential exon usage in RNA-Seq data. _DEXSeq_ employs generalized linear models and offers good detection power and reliable control of false discoveries by taking biological variation into account. An implementation is available as an R/Bioconductor package
Spatio-temporal epidemic modelling using additive-multiplicative intensity models
An extension of the stochastic susceptible-infectious-recovered (SIR) model is proposed in order to accommodate a regression context for modelling infectious disease surveillance data. The proposal is based on a multivariate counting process specified by conditional intensities, which contain an additive epidemic component and a multiplicative endemic component. This allows the analysis of endemic infectious diseases by quantifying risk factors for infection by external sources in addition to infective contacts. Simulation from the model is straightforward by Ogata's modified thinning algorithm. Inference can be performed by considering the full likelihood of the stochastic process with additional parameter restrictions to ensure non-negative conditional intensities.
As an illustration we analyse data provided by the Federal Research Centre for Virus Diseases of Animals, Wusterhausen, Germany, on the incidence of the classical swine fever virus in Germany during 1993-2004
Increasing levels of the endocannabinoid 2-AG is neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease
Date of Acceptance: 28/07/2015 The authors are grateful to the staff of the Medical Research Facility for their help with the animal care. This work was supported by the NHS Endowment fund 09/03 and the Wellcome Trust (WT080782MF). We thank Merck & Co. Inc., Rathway NJ, USA for the supply of DFU.Peer reviewedPublisher PD
Cross correlations in mesoscopic charge detection
We study a tunnel contact that acts as charge detector for a single-electron
transistor (SET) focusing on correlations between the detector current and the
current through the SET. This system can be described fully by a Markovian
master equation for the SET, while electron tunneling in the charge monitor
represents a process with a stochastic rate, which can be solved exactly. It
turns out that current monitoring is possible as long as the detector current
correlates with the currents through either SET barrier. By contrast,
correlations with the effective current according to the Ramo-Shockley theorem
are not essential. Moreover, we propose the measurement of the SET barrier
capacitances.Comment: 7 pages, 2 figure
Comparative Enumeration Gene Expression
This paper is about differential gene expression measured by transcript counting methods such as SAGE or MPSS. It introduces two significance tests for detection of differential expressed tags: frequentist and Bayesian. Under the frequentist view, it is proposed a test that computes the critical level as a function of each tag total frequency. Under the Bayesian view the Full Bayesian Significance Test is used considering the logistic normal distribution. The two proposed significance levels, the frequentist and the Bayesian, are compared for a data set with four libraries. The linking function between them is a Beta distribution function with mean 0.39 and standard deviation 0.30
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