59 research outputs found

    Disparate dispersal limitation in Geomalacus slugs unveiled by the shape and slope of the genetic–spatial distance relationship

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    Long‐term dispersal ability is a key species’ trait constraining species ranges and thus large‐scale biodiversity patterns. Here we infer the long‐term dispersal abilities of three Geomalacus (Gastropoda, Pulmonata) species from their range‐wide genetic–spatial distance relationships. This approach follows recent advances in statistical modelling of the analogous pattern at the community level: the distance decay in assemblage similarity. While linear relationships are expected for species with high long‐term dispersal abilities, asymptotic relationships are expected for those with more restricted mobility. We evaluated three functional forms (linear, negative exponential and power‐law) for the relationship between genetic distance (computed from mitochondrial cox1 sequences, n = 701) and spatial distance. Range fragmentation at present time and at the Last Glacial Maximum was also estimated based on the projection of climatic niches. The power‐law function best fit the relationship between genetic and spatial distances, suggesting strong dispersal limitation and long‐term population isolation in all three species. However, the differences in slope and explained variance pointed to disparities in dispersal ability among these weak dispersers. Phylogeographic patterns of Geomalacus species are thus largely driven by the same major process (i.e. dispersal limitation), operating at different strengths. This strong dispersal limitation results in geographic clustering of genetic diversity that makes these species highly vulnerable to genetic erosion due to climate changThe authors were supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (ERDF) through grant CGL2016‐76637‐P and fellowship IJCI‐2014‐20881 to CG‐RS

    A feature selection approach for identification of signature genes from SAGE data

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    <p>Abstract</p> <p>Background</p> <p>One goal of gene expression profiling is to identify signature genes that robustly distinguish different types or grades of tumors. Several tumor classifiers based on expression profiling have been proposed using microarray technique. Due to important differences in the probabilistic models of microarray and SAGE technologies, it is important to develop suitable techniques to select specific genes from SAGE measurements.</p> <p>Results</p> <p>A new framework to select specific genes that distinguish different biological states based on the analysis of SAGE data is proposed. The new framework applies the bolstered error for the identification of strong genes that separate the biological states in a feature space defined by the gene expression of a training set. Credibility intervals defined from a probabilistic model of SAGE measurements are used to identify the genes that distinguish the different states with more reliability among all gene groups selected by the strong genes method. A score taking into account the credibility and the bolstered error values in order to rank the groups of considered genes is proposed. Results obtained using SAGE data from gliomas are presented, thus corroborating the introduced methodology.</p> <p>Conclusion</p> <p>The model representing counting data, such as SAGE, provides additional statistical information that allows a more robust analysis. The additional statistical information provided by the probabilistic model is incorporated in the methodology described in the paper. The introduced method is suitable to identify signature genes that lead to a good separation of the biological states using SAGE and may be adapted for other counting methods such as Massive Parallel Signature Sequencing (MPSS) or the recent Sequencing-By-Synthesis (SBS) technique. Some of such genes identified by the proposed method may be useful to generate classifiers.</p

    Healthy lifestyle behaviors and the periodicity of mammography screening in brazilian women

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    INTRODUCTION: Certain behaviors have been associated with health promotion, including mammography screening, in women worldwide. OBJECTIVE: The objective of this study was to determine whether there is an association between the periodicity of mammography screening and healthy lifestyle behaviors in Brazilian women employed at a public university in Bahia, Brazil. METHODS: A total of 635 women of 50–69 years of age at the time of the interview, from the Brazilian Longitudinal Study of Adult Health cohort who were resident in Bahia, participated in the study. Data were collected using a multidimensional questionnaire that included questions on participants’ sociodemographic characteristics and health-related behaviors (smoking, alcohol consumption, leisure-time physical activity and diet) and another questionnaire that dealt with risk factors and breast cancer screening. Measures of association were calculated using simple and multivariate logistic regression. RESULTS: The practice of physical activity, not smoking, moderate alcohol consumption and a healthy diet were the health behaviors most adopted by the women who had last had a mammogram ⩽2 years previously (which is in line with the interval recommended by the Brazilian Ministry of Health). A statistically significant association was found between a lapse of ⩾3 years since last undergoing mammography screening and excessive alcohol consumption, while a borderline association was found between the same screening interval and leisure-time physical inactivity. CONCLUSION: There was an association between lifestyle risk behaviors and a longer time interval between mammography screenings. The present results contribute to the debate on the use of mammography, lifestyle behaviors and health promotion among women

    Isometries, submetries and distance coordinates on Finsler manifolds

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    This paper considers fundamental issues related to Finslerian iso- metries, submetries, distance and geodesics. It is shown that at each point of a Finsler manifold there is a distance coordinate system. Us- ing distance coordinates, a simple proof is given for the Finslerian version of the Myers-Steenrod theorem and for the differentiability of Finslerian submetries

    Review on computational methods for Lyapunov functions

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    Lyapunov functions are an essential tool in the stability analysis of dynamical systems, both in theory and applications. They provide sufficient conditions for the stability of equilibria or more general invariant sets, as well as for their basin of attraction. The necessity, i.e. the existence of Lyapunov functions, has been studied in converse theorems, however, they do not provide a general method to compute them. Because of their importance in stability analysis, numerous computational construction methods have been developed within the Engineering, Informatics, and Mathematics community. They cover different types of systems such as ordinary differential equations, switched systems, non-smooth systems, discrete-time systems etc., and employ di_erent methods such as series expansion, linear programming, linear matrix inequalities, collocation methods, algebraic methods, set-theoretic methods, and many others. This review brings these different methods together. First, the different types of systems, where Lyapunov functions are used, are briefly discussed. In the main part, the computational methods are presented, ordered by the type of method used to construct a Lyapunov function

    Monitoreo del progreso del alumno en la identificación de riesgo en la lectura

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    Este estudo tem por nalidade analisar o uso da monitorização com base no currículo como sistema escolar de identi cação de alunos em risco na leitura, no contexto de um modelo educativo baseado no grau de resposta à intervenção. Realizou-se uma investigação quantitativa em que participaram todos os alunos do 3o ano (82 alunos) de um agrupamento de escolas do norte de Portugal. O tratamento de dados foi feito com recurso à estatística descritiva e inferencial. Destacam-se, entre outras conclusões, a existência de dez alunos em risco na leitura durante todo o ano letivo e o facto de, no nal do 3o ano de escolaridade, a média de resultados dos alunos que nunca estiveram em risco ser superior ao dobro da média de resultados dos alunos que estiveram em risco todo o ano.This study aims to analyze the use of curriculum-based monitoring as a school system to identify students at risk in reading, in the context of an educational model based on the degree of response to intervention. A quantitative investigation was conducted with all third grade students (82 students) from a group of schools in the north of Portugal. Data processing was done using descriptive and inferential statistics. Among the conclusions, the following stand out: the existence of ten students at risk in reading throughout the school year and the fact that, at the end of the third year of schooling, the mean results of students who were never at risk was more than double the mean results of students who were at risk for the entire year.Cette étude a pour but d’analyser l’usage du contôle ayant pour base le coursus comme système scolaire d’identification des élèves présentant des risques dans la lecture, dans le contexte d’un modèle éducatif fondé sur le degrée de réponse à l’intervention. On a fait une investigation quantitative à laquelle ont participé tous les élèves de CM1 (82 élèves) d’un groupement d’écoles du nord du Portugal. Le traitement des données a été fait à l’aide de la statistique descriptive et inférentielle. On souligne, entre autres conclusions, l’existence de dix élèves en risque dans la lecture pendant toute l’année scolaire et le fait qu’à la fin de la troisièmme année de scolarité, la moyenne des résultats des élèves n’ayant jamais été en risque soit supérieur au double de la moyenne des résultats des élèves qui ont été en risque toute l’année.Este estudio tiene la finalidad de analizar el uso del monitoreo del currículo como sistema escolar de identificación de alumnos en riesgo en la lectura, en el marco de un modelo educativo basado en el grado de respuesta a la intervención. Se llevó a cabo una investigación cuantitativa en la que participaron todos los alumnos del 3er año (82 alumnos) de un agrupamiento de escuelas del norte de Portugal. El tratamiento de datos se efectuó por medio de la estadística descriptiva e de inferencias. Se destacan, entre otras conclusiones, la existencia de diez alumnos en riesgo en la lectura durante todo el año lectivo y el hecho de que, al final del 3er año de escolaridad, el promedio de resultados de los alumnos que nunca estuvieron en riesgo era superior al doble del promedio de resultados de los alumnos que estuvieron en riesgo todo el año.(undefined)info:eu-repo/semantics/publishedVersio

    Expression and function of G-protein-coupled receptorsin the male reproductive tract

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    This review focuses on the expression and function of muscarinic acetylcholine receptors (mAChRs), α1-adrenoceptors and relaxin receptors in the male reproductive tract. The localization and differential expression of mAChR and α1-adrenoceptor subtypes in specific compartments of the efferent ductules, epididymis, vas deferens, seminal vesicle and prostate of various species indicate a role for these receptors in the modulation of luminal fluid composition and smooth muscle contraction, including effects on male fertility. Furthermore, the activation of mAChRs induces transactivation of the epidermal growth factor receptor (EGFR) and the Sertoli cell proliferation. The relaxin receptors are present in the testis, RXFP1 in elongated spermatids and Sertoli cells from rat, and RXFP2 in Leydig and germ cells from rat and human, suggesting a role for these receptors in the spermatogenic process. The localization of both receptors in the apical portion of epithelial cells and smooth muscle layers of the vas deferens suggests an involvement of these receptors in the contraction and regulation of secretion.Esta revisão enfatiza a expressão e a função dos receptores muscarínicos, adrenoceptores α1 e receptores para relaxina no sistema reprodutor masculino. A expressão dos receptores muscarínicos e adrenoceptores α1 em compartimentos específicos de dúctulos eferentes, epidídimo, ductos deferentes, vesícula seminal e próstata de várias espécies indica o envolvimento destes receptores na modulação da composição do fluido luminal e na contração do músculo liso, incluindo efeitos na fertilidade masculina. Além disso, a ativação dos receptores muscarínicos leva à transativação do receptor para o fator crescimento epidermal e proliferação das células de Sertoli. Os receptores para relaxina estão presentes no testículo, RXFP1 nas espermátides alongadas e células de Sertoli de rato e RXFP2 nas células de Leydig e germinativas de ratos e humano, sugerindo o envolvimento destes receptores no processo espermatogênico. A localização de ambos os receptores na porção apical das células epiteliais e no músculo liso dos ductos deferentes de rato sugere um papel na contração e na regulação da secreção.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de FarmacologiaUNIFESP, EPM, Depto. de FarmacologiaSciEL
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