Numerical convergence of the block-maxima approach to the Generalized Extreme Value distribution

In this paper we perform an analytical and numerical study of Extreme Value distributions in discrete dynamical systems. In this setting, recent works have shown how to get a statistics of extremes in agreement with the classical Extreme Value Theory. We pursue these investigations by giving analytical expressions of Extreme Value distribution parameters for maps that have an absolutely continuous invariant measure. We compare these analytical results with numerical experiments in which we study the convergence to limiting distributions using the so called block-maxima approach, pointing out in which cases we obtain robust estimation of parameters. In regular maps for which mixing properties do not hold, we show that the fitting procedure to the classical Extreme Value Distribution fails, as expected. However, we obtain an empirical distribution that can be explained starting from a different observable function for which Nicolis et al. [2006] have found analytical results.Comment: 34 pages, 7 figures; Journal of Statistical Physics 201

A novel genetic variant of Streptococcus pneumoniae serotype 11A discovered in Fiji.

OBJECTIVES: As part of annual cross-sectional Streptococcus pneumoniae carriage surveys in Fiji (2012-2015), we detected pneumococci in over 100 nasopharyngeal swabs that serotyped as '11F-like' by microarray. We examined the genetic basis of this divergence in the 11F-like capsular polysaccharide (cps) locus compared to the reference 11F cps sequence. The impact of this diversity on capsule phenotype, and serotype results using genetic and serologic methods were determined. METHODS: Genomic DNA from representative 11F-like S. pneumoniae isolates obtained from the nasopharynx of Fijian children was extracted and subject to whole genome sequencing. Genetic and phylogenetic analyses were used to identify genetic changes in the cps locus. Capsular phenotypes were evaluated using the Quellung reaction and latex agglutination. RESULTS: Compared to published 11F sequences, the wcwC and wcrL genes of the 11F-like cps locus are phylogenetically divergent, and the gct gene contains a single nucleotide insertion within a homopolymeric region. These changes within the DNA sequence of the 11F-like cps locus have modified the antigenic properties of the capsule, such that 11F-like isolates serotype as 11A by Quellung reaction and latex agglutination. CONCLUSIONS: This study demonstrates the ability of molecular serotyping by microarray to identify genetic variants of S. pneumoniae and highlights the potential for discrepant results between phenotypic and genotypic serotyping methods. We propose that 11F-like isolates are not a new serotype but rather are a novel genetic variant of serotype 11A. These findings have implications for invasive pneumococcal disease surveillance as well as studies investigating vaccine impact

A review of diagnostic and functional imaging in headache

The neuroimaging of headache patients has revolutionised our understanding of the pathophysiology of primary headaches and provided unique insights into these syndromes. Modern imaging studies point, together with the clinical picture, towards a central triggering cause. The early functional imaging work using positron emission tomography shed light on the genesis of some syndromes, and has recently been refined, implying that the observed activation in migraine (brainstem) and in several trigeminal-autonomic headaches (hypothalamic grey) is involved in the pain process in either a permissive or triggering manner rather than simply as a response to first-division nociception per se. Using the advanced method of voxel-based morphometry, it has been suggested that there is a correlation between the brain area activated specifically in acute cluster headache — the posterior hypothalamic grey matter — and an increase in grey matter in the same region. No structural changes have been found for migraine and medication overuse headache, whereas patients with chronic tension-type headache demonstrated a significant grey matter decrease in regions known to be involved in pain processing. Modern neuroimaging thus clearly suggests that most primary headache syndromes are predominantly driven from the brain, activating the trigeminovascular reflex and needing therapeutics that act on both sides: centrally and peripherally

Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel

A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved

Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

Peer reviewe

Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

Peer reviewe

Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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