Browsing by Issue Date, starting with "2011-02"
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- The Lusitania Province as a center of diversification: the phylogeny of the genus Microlipophrys (Pisces: Blenniidae)Publication . Martínez-Levy, Gabriela A.; Wirtz, Peter; Floeter, S. R.; Almada, V. C.The Lusitania Province has been considered a transition zone between the Atlantic northern cold waters and Tropical warm waters. Tropical species have expanded their ranges during warm periods and either retreated during cold periods or survived in local refuges. Successive waves of dispersion into this Province could have favored diversification through geographic isolation. Taxa that remained in this large Province may also have diversified in loco. We analyzed molecular markers of the genus Microlipophrys (family Blenniidae) that confirm the validity of this genus and of the seven recognized species. Microlipophrys and its sister clade apparently originated within Lusitania and dispersed into the tropics at a later stage. (C) 2010 Elsevier Inc. All rights reserved.
- Assessment of psychopathological problems in school context: the psychometric properties of a portuguese version of the adolescent psychopathology scale – short formPublication . Lemos, Ida; Faísca, Luís; Valadas, Sandra T.The psychometric properties of a Portuguese version of the Adolescent Psychopathology Scale–Short Form (APS-SF) were studied in a sample of 656 Portuguese adolescents, aged 12 to 19 years, assessed in school context. Also, the aim of the study was to gather data concerning age-and gender-related differences in the expression of psychopathological problems assessed by the APS-SF. Results of the reliability of APS-SF scales are compared with those obtained by Reynolds in the validation studies with the American sample. Factor analysis reproduced the bidimensionality of the original validation studies of the scale. These findings seem to support the use of the APS-SF as a valuable tool for early identification of psychosocial problems in the school context in Portuguese adolescents. Results concerning age-and gender-related differences in the expression of psychopathological problems in the adolescents are discussed.
- Survival of Escherichia coli in the environment: fundamental and public health aspectsPublication . van Elsas, Jan Dirk; Semenov, Alexander V.; Costa, Rodrigo; Trevors, Jack T.In this review, our current understanding of the species Escherichia coli and its persistence in the open environment is examined. E. coli consists of six different subgroups, which are separable by genomic analyses. Strains within each subgroup occupy various ecological niches, and can be broadly characterized by either commensalistic or different pathogenic behaviour. In relevant cases, genomic islands can be pinpointed that underpin the behaviour. Thus, genomic islands of, on the one hand, broad environmental significance, and, on the other hand, virulence, are highlighted in the context of E. coli survival in its niches. A focus is further placed on experimental studies on the survival of the different types of E. coli in soil, manure and water. Overall, the data suggest that E. coli can persist, for varying periods of time, in such terrestrial and aquatic habitats. In particular, the considerable persistence of the pathogenic E. coli O157:H7 is of importance, as its acid tolerance may be expected to confer a fitness asset in the more acidic environments. In this context, the extent to which E. coli interacts with its human/animal host and the organism's survivability in natural environments are compared. In addition, the effect of the diversity and community structure of the indigenous microbiota on the fate of invading E. coli populations in the open environment is discussed. Such a relationship is of importance to our knowledge of both public and environmental health. The ISME Journal (2011) 5, 173-183; doi:10.1038/ismej.2010.80; published online 24 June 2010
- Calculando em cadeiaPublication . Veia, Luciano; Lourenço, GuidaO artigo relata una experiência de sala de aula, no 2.º ano de escolaridade, em que os alunos se envolvem com grande entusiasmo na exploração de cadeias numéricas de subtração.
- Insights into the demographic history of african pygmies from complete mitochondrial genomesPublication . Batini, Chiara; Lopes, Joao; Behar, Doron M.; Calafell, Francesc; Jorde, Lynn B.; van der Veen, Lolke; Quintana-Murci, Lluis; Spedini, Gabriella; Destro Bisol, Giovanni; Comas, DavidPygmy populations are among the few hunter-gatherers currently living in sub-Saharan Africa and are mainly represented by two groups, Eastern and Western, according to their current geographical distribution. They are scattered across the Central African belt and surrounded by Bantu-speaking farmers, with whom they have complex social and economic interactions. To investigate the demographic history of Pygmy groups, a population approach was applied to the analysis of 205 complete mitochondrial DNA (mtDNA) sequences from ten central African populations. No sharing of maternal lineages was observed between the two Pygmy groups, with haplogroup L1c being characteristic of the Western group but most of Eastern Pygmy lineages falling into subclades of L0a, L2a, and L5. Demographic inferences based on Bayesian coalescent simulations point to an early split among the maternal ancestors of Pygmies and those of Bantu-speaking farmers (similar to 70,000 years ago [ya]). Evidence for population growth in the ancestors of Bantu-speaking farmers has been observed, starting similar to 65,000 ya, well before the diffusion of Bantu languages. Subsequently, the effective population size of the ancestors of Pygmies remained constant over time and similar to 27,000 ya, coincident with the Last Glacial Maximum, Eastern and Western Pygmies diverged, with evidence of subsequent migration only among the Western group and the Bantu-speaking farmers. Western Pygmies show signs of a recent bottleneck 4,000-650 ya, coincident with the diffusion of Bantu Languages, whereas Eastern Pygmies seem to have experienced a more ancient decrease in population size (20,000-4,000 ya). In conclusion, the results of this first attempt at analyzing complete mtDNA sequences at the population level in sub-Saharan Africa not only support previous findings but also offer new insights into the demographic history of Pygmy populations, shedding new light on the ancient peopling of the African continent.
- New approach for segmentation and quantification of two-dimensional gel electrophoresis imagesPublication . Dos Anjos, António; Moller, Anders L. B.; Ersboll, Bjarne K.; Finnie, Christine; Shahbazkia, Hamid R.Motivation: Detection of protein spots in two-dimensional gel electrophoresis images (2-DE) is a very complex task and current approaches addressing this problem still suffer from significant shortcomings. When quantifying a spot, most of the current software applications include a lot of background due to poor segmentation. Other software applications use a fixed window for this task, resulting in omission of part of the protein spot, or including background in the quantification. The approach presented here for the segmentation and quantification of 2-DE aims to minimize these problems. Results: Five sections from different gels are used to test the performance of the presented method concerning the detection of protein spots, and three gel sections are used to test the quantification of sixty protein spots. Comparisons with a state-of-the-art commercial software and an academic state-of-the-art approach are presented. It is shown that the proposed approach for segmentation and quantification of 2-DE images can compete with the available commercial and academic software packages.
- Erosões localizadas junto de pilares simples: efeito do diâmetro relativo do sedimento na profundidade de equilibrio de cavidades de erosãoPublication . Lança, Rui; Pêgo, João; Maia, Rodrigo; Fael, CristinaA comunicação apresenta os resultados preliminares de ensaios experimentais, sobre erosões localizadas junto a pilares cilíndricos isolados, realizados nos Laboratórios de Hidráulica das Faculdades de Engenharia da Universidade da Beira Interior (UBI) e da Universidade do Porto (FEUP). Nesse âmbito, foram realizados treze ensaios com o objectivo de analisar o efeito do diâmetro relativo do sedimento e da profundidade relativa do escoamento de aproximação na profundidade de equilíbrio das cavidades de erosão normalizada pelo diâmetro do pilar. Os ensaios foram realizados em condições de leito fixo (i.e., sem transporte sólido generalizado) e com durações compreendidas entre 4,1 e 12,9 dias. O conjunto de ensaios foi definido de modo a que a gama de parâmetros utilizada fosse o mais alargada possível, perspectivando, desta forma, tirar conclusões mais abrangentes do que as correspondentes à maioria dos trabalhos existentes neste domínio. As séries temporais do desenvolvimento da profundidade máxima das cavidades de erosão em pilares cilíndricos isolados foram analisadas e tratadas de acordo com metodologia proposta por Lança et al. (2010). Os resultados revelam que há uma forte dependência entre a profundidade de equilíbrio das cavidades de erosão em pilares cilíndricos isolados e o diâmetro relativo do sedimento, confirmando os resultados apresentados por Sheppard et al. (1995; 1999; 2004). Contrariando o instituído por alguma literatura da especialidade de referência, foi observado que a profundidade de equilíbrio das cavidades de erosão normalizada pelo diâmetro do pilar decresce com o diâmetro relativo do sedimento para valores superiores a ~100. Este efeito é possivelmente uma das causas da sobrestimação da profundidade de equilíbrio das cavidades de erosão obtidas através de fórmulas de uso reconhecido e que foram determinadas com base em trabalhos laboratoriais.