Alex Karagrigoriou

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The trials performed worldwide toward noninvasive prenatal diagnosis (NIPD) of Down's syndrome (or trisomy 21) have shown the commercial and medical potential of NIPD compared to the currently used invasive prenatal diagnostic procedures. Extensive investigation of methylation differences between the mother and the fetus has led to the identification of(More)
INTRODUCTION Non-invasive prenatal diagnosis (NIPD) of Down syndrome is rapidly evolving. Currently, two applications for NIPD of Down syndrome have been developed with potential and have displayed positive results; the NIPD using next-generation sequencing technologies and the NIPD using the methylated DNA immunoprecipitation (MeDIP) real-time quantitative(More)
OBJECTIVE To reevaluate the efficiency of the 12 differentially methylated regions (DMRs) used in the methylated DNA immunoprecipitation (MeDIP) real-time quantitative polymerase chain reaction (real-time qPCR) based approach, develop an improved version of the diagnostic formula and perform a larger validation study. METHODS Twelve selected DMRs were(More)
In this paper, we propose a test of fit based on maximum entropy. The asymptotic distribution of the proposed test statistic is established and a corrected form for small and medium sample sizes is furnished. The performance of the test is investigated through extensive Monte Carlo simulations. Real examples are also presented and analyzed.
In this paper, the variable selection strategies (criteria) are thoroughly discussed and their use in various survival models is investigated. The asymptotic efficiency property, in the sense of Shibata Ann Stat 8: 147-164, 1980, of a class of variable selection strategies which includes the AIC and all criteria equivalent to it, is established for a(More)
In this work we explore the class of heavy-tailed distributions and discuss their signicance in reliability engineering. At the same time we discuss measures of divergence which are extensively used in statistics in various elds. In this paper we rely on such measures to evaluate the residual and past lifetimes of events which are associated with the tail(More)
In this paper a test procedure is proposed for the skewness in autoregressive conditional volatility models. The size and the power of the test are investigated through a series of Monte Carlo simulations with various models. Furthermore, applications with financial data are analyzed in order to explore the applicability and the capabilities of the proposed(More)
This work is based on the Cyprus Survey of Consumer Finances (CySCF) and focuses on one hand on the composition of household assets in Cyprus based on the 2002 Cyprus Survey of Consumer Finances (CySCF2002) and on the other on the distributional changes between the 1999 and the 2002 CySCFs. From 1999 to 2002 there has been a radical increase of household(More)
Markov processes are widely used for reliability analysis because the number of failures in arbitrary time intervals in many practical cases can be described as a Poisson process and the time up to the failure and repair time are often exponentially distributed. In this work we focus on the estimation of both the intensity rates and transition probabilities(More)