332 research outputs found

    Survival-extinction phase transition in a bit-string population with mutation

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    A bit-string model for the evolution of a population of haploid organisms, subject to competition, reproduction with mutation and selection is studied, using mean field theory and Monte Carlo simulations. We show that, depending on environmental flexibility and genetic variability, the model exhibits a phase transtion between extinction and survival. The mean-field theory describes the infinite-size limit, while simulations are used to study quasi-stationary properties.Comment: 11 pages, 5 figure

    Fluctuations of an evaporating black hole from back reaction of its Hawking radiation: Questioning a premise in earlier work

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    This paper delineates the first steps in a systematic quantitative study of the spacetime fluctuations induced by quantum fields in an evaporating black hole. We explain how the stochastic gravity formalism can be a useful tool for that purpose within a low-energy effective field theory approach to quantum gravity. As an explicit example we apply it to the study of the spherically-symmetric sector of metric perturbations around an evaporating black hole background geometry. For macroscopic black holes we find that those fluctuations grow and eventually become important when considering sufficiently long periods of time (of the order of the evaporation time), but well before the Planckian regime is reached. In addition, the assumption of a simple correlation between the fluctuations of the energy flux crossing the horizon and far from it, which was made in earlier work on spherically-symmetric induced fluctuations, is carefully analyzed and found to be invalid. Our analysis suggests the existence of an infinite amplitude for the fluctuations of the horizon as a three-dimensional hypersurface. We emphasize the need for understanding and designing operational ways of probing quantum metric fluctuations near the horizon and extracting physically meaningful information.Comment: 10 pages, REVTeX; minor changes, a few references added and a brief discussion of their relevance included. To appear in the proceedings of the 10th Peyresq meeting. Dedicated to Rafael Sorkin on the occasion of his 60th birthda

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

    Apoio Matricial Como Articulador Das Relações Interprofissionais Entre Serviços Especializados E Atenção Primária à Saúde

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    This paper sought to carry out an integrative review of the national production on Matrix Support methodology, whilst encompassing empirical studies on effectiveness and theoretical-methodological review papers on Matrix Support. The used material is comprised of papers that are indexed in the PubMed database, the NLM and the BVS (Virtual Library of Health), between 1999 and 2013, in Portuguese, English and Spanish. We included 28 articles, and its analysis allowed the identification of three categories: 1) foundation goods and consolidation of the concept of matrix support; 2) Review articles on the matrix support; 3) Items arising from empirical research involving the concept of matrix support. The publications showed that the matrix support brings an innovative proposal and powerful to transform the health care model. However, to achieve their goals is necessary to overcome some impasses, several interconnected directly with the implementation of their directives and to overcoming structural problems of the National Health System (SUS). © 2016, Institute de Medicina Social da UERJ. All rights reserved.26245548

    Apoio Matricial No Sus Campinas: Análise Da Consolidação De Uma Prática Interprofissional Na Rede De Saúde

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    This study aims to characterize the teams and the inter-professional work process of Matrix Support developed and practiced in primary healthcare provided by the Brazilian Unified Health System (SUS) in Campinas, São Paulo State, Brazil. This is an exploratory descriptive study involving a questionnaire that was applied to 232 professionals who practice Matrix Support for primary healthcare. For analysis, the data were grouped into four categories: Identification of the professional; Work links to the Campinas SUS; Organization of the Matrix Support work; and the Support practice. The study indicates that the methodology of support for inter-professional work has achieved an important degree of consolidation in the municipality, in spite of the restricted investment. The reduced working time dedicated to support, and the large number of teams supported by each Matrix Support team were identified as the principal points of fragility in the work process. In turn, strong points that emerged were the multiplicity of tools used, the possibility of shared construction of work guidelines, and the flexibility in the composition of the support teams. Both the fragilities and the potentialities found can offer inputs for reflection and full creation of Matrix Support in other contexts. © 2016, Associacao Brasileira de Pos - Graduacao em Saude Coletiva. All rights reserved.2151625163

    Genotype-Phenotype Correlation in NF1: Evidence for a More Severe Phenotype Associated with Missense Mutations Affecting NF1 Codons 844–848

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    Neurofibromatosis type 1 (NF1), a common genetic disorder with a birth incidence of 1:2,000–3,000, is characterized by a highly variable clinical presentation. To date, only two clinically relevant intragenic genotype-phenotype correlations have been reported for NF1 missense mutations affecting p.Arg1809 and a single amino acid deletion p.Met922del. Both variants predispose to a distinct mild NF1 phenotype with neither externally visible cutaneous/plexiform neurofibromas nor other tumors. Here, we report 162 individuals (129 unrelated probands and 33 affected relatives) heterozygous for a constitutional missense mutation affecting one of five neighboring NF1 codons—Leu844, Cys845, Ala846, Leu847, and Gly848—located in the cysteine-serine-rich domain (CSRD). Collectively, these recurrent missense mutations affect ∼0.8% of unrelated NF1 mutation-positive probands in the University of Alabama at Birmingham (UAB) cohort. Major superficial plexiform neurofibromas and symptomatic spinal neurofibromas were more prevalent in these individuals compared with classic NF1-affected cohorts (both p < 0.0001). Nearly half of the individuals had symptomatic or asymptomatic optic pathway gliomas and/or skeletal abnormalities. Additionally, variants in this region seem to confer a high predisposition to develop malignancies compared with the general NF1-affected population (p = 0.0061). Our results demonstrate that these NF1 missense mutations, although located outside the GAP-related domain, may be an important risk factor for a severe presentation. A genotype-phenotype correlation at the NF1 region 844–848 exists and will be valuable in the management and genetic counseling of a significant number of individuals

    Determining the virulence properties of Escherichia coli ST131 containing bacteriocin-encoding plasmids using short-and long-read sequencing and comparing them with those of other E. Coli lineages

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    T. Escherichia coli ST131 is a clinical challenge due to its multidrug resistant profile and successful global spread. They are often associated with complicated infections, particularly urinary tract infections (UTIs). Bacteriocins play an important role to outcompete other microorganisms present in the human gut. Here, we characterized bacteriocin-encoding plasmids found in ST131 isolates of patients suffering from a UTI using both short-and long-read sequencing. Colicins Ia, Ib and E1, and microcin V, were identified among plasmids that also contained resistance and virulence genes. To investigate if the potential transmission range of the colicin E1 plasmid is influenced by the presence of a resistance gene, we constructed a strain containing a plasmid which had both the colicin E1 and blaCMY-2 genes. No difference in transmission range was found between transformant and wild-type strains. However, a statistically significantly difference was found in adhesion and invasion ability. Bacteriocin-producing isolates from both ST131 and non-ST131 lineages were able to inhibit the growth of other E. coli isolates, including other ST131. In summary, plasmids harboring bacteriocins give additional advantages for highly virulent and resistant ST131 isolates, improving the ability of these isolates to compete with other microbiota for a niche and thereby increasing the risk of infection
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