5,368 research outputs found

    Nucleic acids in mummified plant seeds : biochemistry and molecular genetics,of pre-Columbian maize

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    SummaryNucleic acids fractions were isolated from pre-Columbian maize seeds and characterized using different approaches such as polyacrylamide gel electrophoresis, anti-DNA antibody binding, HPLC fractionation, molecular hybridization with cloned genes, and DNA amplification by the polymerase chain reaction. The nucleic acids were found to be very depolymerized (≤140 base pairs in length) and composed mainly of ribosomal RNA. Despite the very low amount and degree of polymerization of seed DNA, specific maize nuclear Mul, Mu4, Mu8 and, possibly, Mu5 element components could be detected, thanks to the use of amplification systems as short as 90 bp. The results suggest that evaluation of the relative proportions of Mu-type element components and, possibly, other maize genomic components in single mummified kernels, may offer a new key to the study of ancient maize populations

    EDITORIAL

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    O presente número da RBCDH mantém e realça as nossas principais características. São 16 artigos de autoria de pesquisadores de vários Estados brasileiros, como Pará, Bahia, São Paulo, Rio de Janeiro, Rio Grande do Sul. O leque temático, como sempre é muito abrangente, com contribuições muito interessantes. Coelho Jr. e Silva analisaram o fenômeno do “cosplay” – o uso de fantasias e adereços para imitar (ou representar) os heróis de gibis, mangás e animés

    Editorial

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    This issue of the Journal of Human Growthand Development (Vol. 22 No. 2) deserves aspecial celebration and represents an importantwatershed.

    A importância da história evolutiva em estudos de ecofisiologia vegetal : exemplos dos cerrados e florestas do Brasil Central

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    Studies that compare physiology, anatomy, and ecology across species have offered some of the best insight into adaptation and evolutionary constraints in plants. As a result, the comparative approach has become increasingly used in studies of plant physiological ecology. The high species diversity of Brazilian biomes provides many excellent opportunities for comparative plant ecophysiology, and could be better exploited for understanding the evolution of plant form and function. In this paper we emphasize the importance of considering phylogenetic information for the design and analysis of comparative studies, relying on examples from comparisons of woody plants from cerrado and gallery (riparian) forests. The use of congeneric species pairs, each containing one cerrado species and one forest species of the same genus, greatly improves statistical power while assuring phylogenetic independence, an essential condition for inference in comparative studies. For example, in a study of seedlings of nine cerrado species and nine forest species, when we ignore phylogenetic relationships, it is not be possible to conclude that cerrado and forest species differ with regard to leaf area ratio (LAR), specific leaf area (SLA), or seedling height. If, however, we use the generic groupings to account for phylogenetic effects, then we find that seedlings of savanna species have lower LAR, SLA, and seedling height. Much of the phylogenetic inertia observed for these traits appears related to the fact that these traits are all strongly correlated with seed mass, which has been previously shown to be strongly conserved phylogenetically. These examples emphasize the importance of phylogenetic information in comparative studies. _________________________________________________________________________________ ABSTRACTEstudos que comparam a fisiologia, anatomia e ecologia das espécies têm oferecido algumas das melhores apreciações sobre as limitações adaptativas e evolucionárias em plantas. Como resultado, a abordagem comparativa tem sido cada vez mais utilizada em estudos de ecofisiologia vegetal. A alta diversidade de espécies dos biomas brasileiros fornece excelentes oportunidades para estudos de ecofisiologia vegetal comparada, uma abordagem que poderia ser melhor explorada em pesquisas que visam a compreensão da evolução da forma e função em plantas. Neste artigo nós enfatizarmos a importância de considerar a informação filogenética no desenho e analises de estudos comparativos, utilizando como exemplos espécies lenhosas do cerrado e de mata de galeria (mata ripária). O uso de pares congenéricos, cada par contendo uma espécie do cerrado e uma espécie de floresta do mesmo gênero, aumenta o poder estatístico das análises, enquanto assegura concomitantemente a independência filogenética, uma condição essencial para inferência em estudos comparativos. Por exemplo, em um estudo comparativo de nove espécies do cerrado e nove de mata, não seria possível concluir que as espécies de cerrado e de mata diferem na razão de área foliar (LAR), área foliar especifica (SLA) e altura da plântula, se as relações filogenéticas forem ignoradas. Entretanto, se utilizarmos agrupamentos genéricos para contabilizar os efeitos filogenéticos, nós vamos encontrar que as plântulas de espécies de cerrado tem menores valores de LAR, SLA e altura da plântula. Muito da inércia filogenética observada para estes atributos em plântulas parece estar relacionada ao fato de que estas características se correlacionam fortemente com a massa da semente, que estudos anteriores demonstraram ser um atributo fortemente conservado em termos filogenéticos. Estes exemplos ressaltam a importância da informação filogenética em estudos comparativos

    A Wigner quasiprobability distribution of work

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    In this article we introduce a quasiprobability distribution of work that is based on the Wigner function. This construction rests on the idea that the work done on an isolated system can be coherently measured by coupling the system to a quantum measurement apparatus. In this way, a quasiprobability distribution of work can be defined in terms of the Wigner function of the apparatus. This quasidistribution contains the information of the work statistics and also holds a clear operational definition. Moreover, it is shown that the presence of quantum coherence in the energy eigenbasis is related with the appearance of characteristics related to non-classicality in the Wigner function such as negativity and interference fringes. On the other hand, from this quasiprobability distribution it is straightforward to obtain the standard two-point measurement probability distribution of work and also the difference in average energy for initial states with coherences.Comment: 11 pages, 3 figure

    On pains and fear in childbirth: dimensions of listening

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    OBJETIVOS: desenvolver algumas reflexões sobre os possíveis efeitos benéficos de uma escuta responsiva à verbalização da presença de dor, medos e seus correlatos na cena do parto tomando como base dados empíricos de pesquisa realizada em maternidade situada na cidade de São Paulo, Brasil. MÉTODOS: estudo descritivo, de metodologia qualitativa, referenciado no quadro teórico da Psicologia Social, Psicanálise e Lingüística, utilizando entrevistas semi-estruturadas com 20 parturientes e sete doulas e observação de rotinas da maternidade. RESULTADOS: a análise, apoiada em categorias estabelecidas (subjetividade auto-referida, intersubjetividade, acolhimento, apropriação da experiência) mostrou, entre outros pontos, a importância e a valorização da interlocução qualificada no processo da parturição. Processo esse referido pelas parturientes como experiência de elevado grau de estresse, com vivências de dor, medos e ansiedades, porém mitigados pelo apoio recebido. CONCLUSÕES: a análise permitiu compreender as relações interpessoais como campo de interlocução e acolhimento percebidos pelas mulheres do estudo capazes de produzir efeitos favoráveis sobre as vivências do estresse materno, configurando-se como recurso técnico, qualificado e valioso, oferecido à parturienteOBJECTIVES: to reflect on the possibilities raised by listening to the life-experiences related by parturient women concerning pain on delivery, using empirical data from research carried out in a Maternity ward in the city of São Paulo, Brazil. METHODS: a descriptive study, with a qualitative methodology, based on the theoretical framework of Social Psychology, Psychoanalysis and Linguistics was carried out, by means of semi-structured interviews with parturient women and midwives, in addition to observation of maternity routines. RESULTS: one of the findings of the analysis, based on established categories (self-referred subjectivity, intersubjectivity, the appropriation of experience), was the importance of accurate interlocution in the course of the parturition process. This process was mentioned by the parturient women as an experience accompanied by a high level of stress, involving pain, fear and anxiety, although these may be mitigated by the support received. CONCLUSIONS: the analysis shed light on the role of interpersonal relationships involving dialogue and physical contact experienced by these women in reducing the stress of childbirth, suggesting that these constitute a valuable and effective resource that should be offered to parturient woma

    Nature Conservation in Brazil in the 20th Century

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    The text explores actors and institutions involved in the conservation of nature in Brazil during the 20th century. It seeks to understand their ideas, themes and proposals while also focusing on their activism. It deals with convergences and divergences between activists and organizations considering the political contexts in which they operated. We conclude that the continuity among actors was difficult but highly important and that it led to the development of integrated public policies that conserve biodiversity and promote the controlled and equitable use of natural resources. We also identified the relevance of ecocentric  environmental ethics, focused on the notion that all species have an intrinsic value.The text explores actors and institutions involved in the conservation of nature in Brazil during the 20th century. It seeks to understand their ideas, themes and proposals while also focusing on their activism. It deals with convergences and divergences between activists and organizations considering the political contexts in which they operated. We conclude that the continuity among actors was difficult but highly important and that it led to the development of integrated public policies that conserve biodiversity and promote the controlled and equitable use of natural resources. We also identified the relevance of ecocentric  environmental ethics, focused on the notion that all species have an intrinsic value.The text explores actors and institutions involved in the conservation of nature in Brazil during the 20th century. It seeks to understand their ideas, themes and proposals while also focusing on their activism. It deals with convergences and divergences between activists and organizations considering the political contexts in which they operated. We conclude that the continuity among actors was difficult but highly important and that it led to the development of integrated public policies that conserve biodiversity and promote the controlled and equitable use of natural resources. We also identified the relevance of ecocentric  environmental ethics, focused on the notion that all species have an intrinsic value

    SOM+PSO : A novel method to obtain classification rules

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    Currently, most processes have a volume of historical information that makes its manual processing difficult. Data mining, one of the most significant stages in the Knowledge Discovery in Databases (KDD) process, has a set of techniques capable of modeling and summarizing these historical data, making it easier to understand them and helping the decision making process in future situations. This article presents a new data mining adaptive technique called SOM+PSO that can build, from the available information, a reduced set of simple classification rules from which the most significant relations between the features recorded can be derived. These rules operate both on numeric and nominal attributes, and they are built by combining a variation of a population metaheuristic and a competitive neural network. The method proposed was compared with the PART method and measured over 19 databases (mostly from the UCI repository), and satisfactory results were obtained.Facultad de Informátic

    SOM+PSO : A novel method to obtain classification rules

    Get PDF
    Currently, most processes have a volume of historical information that makes its manual processing difficult. Data mining, one of the most significant stages in the Knowledge Discovery in Databases (KDD) process, has a set of techniques capable of modeling and summarizing these historical data, making it easier to understand them and helping the decision making process in future situations. This article presents a new data mining adaptive technique called SOM+PSO that can build, from the available information, a reduced set of simple classification rules from which the most significant relations between the features recorded can be derived. These rules operate both on numeric and nominal attributes, and they are built by combining a variation of a population metaheuristic and a competitive neural network. The method proposed was compared with the PART method and measured over 19 databases (mostly from the UCI repository), and satisfactory results were obtained.Facultad de Informátic

    Efficient Exact Maximum a Posteriori Computation for Bayesian SNP Genotyping in Polyploids

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    The problem of genotyping polyploids is extremely important for the creation of genetic maps and assembly of complex plant genomes. Despite its significance, polyploid genotyping still remains largely unsolved and suffers from a lack of statistical formality. In this paper a graphical Bayesian model for SNP genotyping data is introduced. This model can infer genotypes even when the ploidy of the population is unknown. We also introduce an algorithm for finding the exact maximum a posteriori genotype configuration with this model. This algorithm is implemented in a freely available web-based software package SuperMASSA. We demonstrate the utility, efficiency, and flexibility of the model and algorithm by applying them to two different platforms, each of which is applied to a polyploid data set: Illumina GoldenGate data from potato and Sequenom MassARRAY data from sugarcane. Our method achieves state-of-the-art performance on both data sets and can be trivially adapted to use models that utilize prior information about any platform or species
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