On the nonequilibrium statistical operator and classical thermofield dynamics

A nonequilibrium statistical operator (NSO) is built for classical sistems using a eld theory in classical phase space, which is but a classical version of the thermo eld dynamics formalism. The approach developed here starts with a second-quantized version of this phase-space eld theory. Then elements of symmetry are analysed and invariants of the theory are introduced. The local conservation laws are derived and used to make explicit NSO. Such a method is applied to derive the Fokker-Planck-Kramers equation

Inteligência Computacional aplicada à Gestão Universitária: Evasão Discente

Este artigo mostra o desenvolvimento de um sistema para a gestão do fenômeno de evasão discente utilizando a modelagem de redes bayesianas. As redes bayesianas representam o conhecimento sobre o fenômeno em um grafo direcionado acíclico, cujos nós de entrada são os fatores que interferem na evasão e o nó de saída os possíveis resultados de um aluno matriculado em um determinado curso. As simulações foram feitas com base no teorema de Bayes e permitem estimar o risco de evasão de um aluno em um curso, a partir do conhecimento histórico da evasão e dos fatores pessoais do discente. A visão específica da evasão num curso por meio de redes bayesianas permite à administração universitária uma gestão pró-ativa desse fenômeno em nível de cada curso, favorecendo tomadas de decisão no percurso do discente, reduzindo assim o risco de evasão

Evaluation of capillaries with different inner coatings for DNA analysis using dilute polymer solutions by capillary electrophoresis

In this work three capillary columns, one with uncoated inner wall and two with covalently-bound internal coatings - poly(vinyl alcohol) (PVA) and poly(dimethylacrylamide) (PDMA) - both covalently covered - were used to separate DNA fragments and compared to DNA separation using replaceable polymer solutions. The separations were performed using hydroxyethylcellulose (HEC) (90-105 kDa) in concentrations ranging from 0.00 to 2.00% m/v. The results indicated that the separation efficiency was higher in the PVA capillary than in the PDMA in all evaluated concentrations of HEC. In addition, higher resolution was also observed in PVA-coated capillary since in PDMA the shape of the peaks was not reproducible when subsequent runs were performed. Contrary to what has previously been reported in the literature, no reasonable separation was possible in bare fused silica.No presente trabalho, três colunas capilares, uma sem recobrimento interno e duas com recobrimentos internos diferentes foram utilizadas na separação de fragmentos de DNA: poli(vinil álcool) (PVA) e poli(dimetilacrilamida) (PDMA) - ambos de recobrimento covalente - foram comparados para a separação de DNA utilizando soluções poliméricas. As separações foram realizadas usando hidroxietilcelulose (HEC) (90-105 kDa) nas concentrações entre 0,00 e 2,00% m/v. Os resultados indicaram que a eficiência de separação foi maior no capilar de PVA do que no de PDMA, em todas as concentrações de HEC testadas. Ainda, uma resolução superior também foi observada com o capilar de PVA, já que com o capilar de PDMA o formato dos picos não se mostrou reprodutível quando corridas subseqüentes foram realizadas. Contrariamente ao relatado na literatura, nenhuma separação foi conseguida com o capilar sem revestimento interno

Benthic Foraminifera and Bacterial Activity as a Proxy for Environmental Characterization in Potengi Estuary, Rio Grande do Norte, Brazil

The aim of this study was to identify possible zonation patterns and assess the environmental impact on the Potengi River Estuary, Rio Grande do Norte State, through the distribution of benthic foraminifera associated to bacterial activity and abiotic parameters. Six sediment samples were collected from locations that presented clear signs of pollution. The environment was predominantly anaerobic and fermentation occurred at all sites. Forty-two species of foraminifera were identified. The dominant species were Ammonia tepida and Arenoparrella mexicana, which are known to be opportunistic, and able to adapt to rapidly changing conditions. CCA analyses showed that salinity and organic matter, followed by bacterial carbon, were more strongly linked to organism distribution in the Potengi River Estuary. Dissolved oxygen concentration, temperature and total organic matter were higher at the estuary mouth than at the other sites, creating favorable conditions for foraminiferal growth and allowing the faunistic succession on the upper estuary. As foraminifera assemblages when associated to environmental parameters can be used as efficient proxies for environmental diagnosis, these results suggest that the Potengi Estuary is under great stress from the surrounding urban development

Interaction of global and local monopoles

We study the direct interaction between global and local monopoles. While in two previous papers, the coupling between the two sectors was only indirect through the coupling to gravity, we here introduce a new term in the potential that couples the Goldstone field and the Higgs field directly. We investigate the influence of this term in curved space and compare it to the results obtained previously.Comment: 9 Revtex pages, 4 ps-figure

Foraminíferos bentônicos e atividade bacteriana como ferramenta para análise ambiental no Estuário do Rio Pontegi, Rio Grande do Norte, Brasil

The aim of this study was to identify possible zonation patterns and assess the environmental impact on the Potengi River Estuary, Rio Grande do Norte State, through the distribution of benthic foraminifera associated to bacterial activity and abiotic parameters. Six sediment samples were collected from locations that presented clear signs of pollution. The environment was predominantly anaerobic and fermentation occurred at all sites. Forty-two species of foraminifera were identified. The dominant species were Ammonia tepida and Arenoparrella mexicana, which are known to be opportunistic, and able to adapt to rapidly changing conditions. CCA analyses showed that salinity and organic matter, followed by bacterial carbon, were more strongly linked to organism distribution in the Potengi River Estuary. Dissolved oxygen concentration, temperature and total organic matter were higher at the estuary mouth than at the other sites, creating favorable conditions for foraminiferal growth and allowing the faunistic succession on the upper estuary. As foraminifera assemblages when associated to environmental parameters can be used as efficient proxies for environmental diagnosis, these results suggest that the Potengi Estuary is under great stress from the surrounding urban development.Este estudo teve como objetivo estabelecer um modelo de zonação e avaliar o impacto ambiental sofrido pelo estuário do rio Potengi, estado do Rio Grande do Norte, através da distribuição das assembléias de foraminíferos associados à atividade bacteriana e a parâmetros físico-químicos. Seis amostras de sedimento foram coletadas em regiões que apresentavam algum tipo poluição aparente. Predominaram os processos bacterianos anaeróbicos principalmente sulfatoredução no estuário. Foram identificadas quarenta e duas espécies de foraminíferos. As espécies dominantes foram Ammonia tepida e Arenoparrella mexicana, que são conhecidas como oportunistas, pois se adaptam com facilidade as variações ambientais. A análise em CCA mostrou que a salinidade e a matéria orgânica, seguidos pelo carbono bacteriano, conduziram a distribuição dos organismos no estuário. A concentração de oxigênio, temperatura e matéria orgânica total foram mais altas na foz do que em outras estações, criando condições favoráveis ao crescimento de foraminíferos e permitiu uma sucessão faunística em direção ao estuário superior. Assembléias de foraminíferos quando associadas a parâmetros ambientais podem ser usadas como eficientes indicadores para o diagnostico ambiental. Os resultados sugeriram que o estuário do rio Potengi encontra-se sobre condições de grande estresse ambiental provocado pelo desenvolvimento urbano a sua volta

Tolerance to water deficit of cowpea genotypes

Objetivou-se, neste trabalho, avaliar o efeito do déficit hídrico sobre as características fisiológicas e produtivas do feijão-caupi e selecionar genótipos tolerantes à seca. Avaliaram-se a condutância estomática, o potencial hídrico foliar, a temperatura das folhas e a produtividade de grãos de 20 genótipos de feijão-caupi nas condições de solo e clima de Teresina, Piauí, no ano de 2008 e se conduziram dois experimentos em delineamento de blocos ao acaso com 20 tratamentos e quatro repetições, um sob déficit hídrico durante a fase reprodutiva e outro sob irrigação plena, para fins de comparação. O déficit hídrico, que foi obtido aplicando-se aproximadamente metade da lâmina requerida pelo feijão-caupi, reduziu em 72% a condutância estomática, 62% o potencial de água nas folhas, 60% a produção de grãos e aumentou em 11,7% a temperatura foliar. Nas condições de déficit hídrico treze genótipos produziram acima da média (466 kg ha-1), com destaque para o BRS-Paraguaçu, Pingo-de-ouro-1-2 e Pingo-de-ouro-2, que produziram 712 kg ha-1, 667 kg ha-1 e 642 kg ha-1, respectivamente. Em média, a produtividade de grãos dos genótipos sob irrigação plena foi 150% superior.The objective of this study was to evaluate physiological and productive characteristics of cowpea under water deficit and total irrigation, under soil and climate conditions of Teresina, Piauí State, in 2008. The stomatal conductance, leaf water potential, leaf temperature and grain yield of twenty cowpea cultivars were evaluated. Two experiments were carried out in a randomized block design with 20 treatments and four replications, one under water deficit during the reproductive phase and another one under total irrigation. The water deficit was obtained applying half of the water depth required by cowpea. The water deficit reduced 72% of the stomatal conductance, 40% the leaf transpiration, 62% of the leaf water potential, 60% of the grain yield and increased 11.7% the leaf temperature. Under water deficit, 13 genotypes produced above average (466 kg ha-1), and BRS-Paraguaçu, Pingo-de-ouro-1-2 and Pingo-de-ouro-2 presented the best grain yield with712 kg ha-1, 667 kg ha-1 and 642 kg ha-1, respectively. The average grain yield of the experiment under total irrigation was 150% higher

Cultivation-independent methods applied to the microbial prospection of oil and gas in soil from a sedimentary basin in Brazil

The upper parts of oil field structures may leak gas which is supposed to be indirectly detected by the soil bacterial populations. Such microorganisms are capable of consuming this gas, supporting the Microbial Prospection of Oil and Gas (MPOG) methodology. The goal of the present work was to characterize microbial communities involved in short-chain alkane metabolism, namely methane, ethane and propane, in samples from a petroliferous (P) soil through clone libraries of the 16S rRNA gene of the Domains Bacteria and Archaea and the catabolic gene coding for the soluble di-iron monooxygenase (SDIMO) enzyme alpha subunit. The microbial community presented high abundance of the bacterial phylum Actinobacteria, which represented 53% of total clones, and the Crenarchaeota group I.1b from the Archaea Domain. The analysis of the catabolic genes revealed the occurrence of seven Operational Protein Families (OPF) and higher richness (Chao = 7; Ace = 7.5) and diversity (Shannon = 1.09) in P soil when compared with a non-petroliferous (Np) soil (Chao = 2; Ace = 0, Shannon = 0.44). Clones related to the ethene monooxygenase (EtnC) and methane monooxygenase (MmoX) coding genes occurred only in P soil, which also presented higher levels of methane and lower levels of ethane and propane, revealed by short-chain hydrocarbon measures. Real-time PCR results suggested that the SDIMO genes occur in very low abundance in the soil samples under study. Further investigations on SDIMOs genes in natural environments are necessary to unravel their still uncharted diversity and to provide reliable tools for the prospection of degrading populations

Agreement between BMI and body fat obesity definitions in a physically active population

Body mass index (BMI) is a widely used proxy of body composition (BC). Concerns exist regarding possible BMI misclassification among active populations. We compared the prevalence of obesity as categorized by BMI or by skinfold estimates of body fat percentage (BF%) in a physically active population. Subjects and methods 3,822 military firefighters underwent a physical fitness evaluation including cardiorespiratory fitness (CRF) by the 12 min-Cooper test, abdominal strength by sit-up test (SUT) and body composition (BC) by BF% (as the reference), as well as BMI. Obesity was defined by BF% > 25% and BMI ≥ 30 kg/m2. Agreement was evaluated by sensitivity and specificity of BMI, positive and negative predictive values (PPV/NPV), positive and negative likelihood (LR+/LR-), receiver operating characteristic (ROC) curves and also across age, CRF and SUT subgroups. Results The prevalence of obesity estimated by BMI (13.3%) was similar to BF% (15.9%). Overall agreement was high (85.8%) and varied in different subgroups (75.3-94.5%). BMI underestimated the prevalence of obesity in all categories with high specificity (≥ 81.2%) and low sensitivity (≤ 67.0). All indices were affected by CRF, age and SUT, with better sensitivity, NPV and LR- in the less fit and older groups; and higher specificity, PPV and LR+ among the fittest and youngest groups. ROC curves showed high area under the curve (≥ 0.77) except for subjects with CRF ≥ 14 METs (= 0.46). Conclusion Both measures yielded similar obesity prevalences, with high agreement. BMI did not overestimate obesity prevalence. BMI ≥ 30 was highly specific to exclude obesity. Because of systematic under estimation, a lower BMI cut-off point might be considered in this population

A LINEAR PROGRAMMING APPROACH FOR REGIONAL POLE PLACEMENT UNDER POINTWISE CONSTRAINTS

Abstract This paper considers the problem of control of discrete-time linear systems under several complicating features frequently encountered in practice : uncertain parameters in the model, additive noise, linear symmetrical state and input constraints. The main control design objective, beyond local stabilization, is to locate the closed-loop poles in a "good" region of the unit disc of the complex plane. The originality of the proposed approach is to use Linear Programming as the basic design tool. It is shown that the matrix conditions derived from positive invariance relations and from design constraints can be formulated as linear matrix equalities and scalar inequalities. The control design problem can then be solved by Linear Programming, with an objective function describing the search for a trade-off between several design objectives