Nouveautés sur les débits monstrueux de l'Amazone...

Après une première étude sur les variations saisonnières de l'Amazone, Maurice Pardé proposait en 1954 à la communauté hydrologique la valeur de 100000 à 110000 m3/s comme module de ce fleuve géant qui draine un bassin de plus de 6000000 km2. Ce résultat, que certains jugeaient alors excessif, était basé sur les observations de son compatriote Paul Le Cointe, et sur le calcul d'un bilan hydrique rudimentaire, du fait du très petit nombre de données hydroclimatiques disponibles à cette époque. Après les premiers jaugeages de l'Amazone à Obidos par l'USGS en 1963-64, le module de plus puissant fleuve du monde était alors estimé à 170000-190000 m3/s, attestant ainsi que la première estimation de Pardé n'était absolument pas surestimée... Les résultats obtenus dans le cadre du programme HIBAM (Hidrologia de Bacia Amazonica, DNAEE/CNPq-ORSTOM) ont permis de préciser le régime de l'Amazone et de ses principaux tributaires. Les apports des différents sous-bassins et le module de l'Amazone à son embouchure ont pu être estimés avec une assez bonne précision, ce qui a rendu possible la régionalisation des débits annuels. (Résumé d'auteur

Recomendações para operacionalização do plano de Agricultura de Baixo Carbono (ABC) no Pantanal.

O Governo Brasileiro assumiu voluntariamente durante a COP-15 (Conferência das Nações Unidas sobre Mudança do Clima), realizada em Kopenhagen em 2009, o compromisso de redução de 36,1% a 38,9% da emissão de Gases Efeito Estufa (GEEs) até o ano 2020. As estimativas apontam para um total de emissão de 3.236 milhões de toneladas de CO2 equivalente pela agricultura, nas condições atuais dos sistemas de produção, havendo, portanto a necessidade da implantação de ações que promovam a redução de 1.168 a 1.259 milhões de toneladas de CO2 equivalente até esta data. É sabido que todas as atividades agropecuárias, praticadas nos diferentes biomas brasileiros, são consideradas como as grandes emissoras de Gases de Efeito Estufa, sendo a exploração pecuária extensiva uma das grandes emissoras destes gases. A pecuária de corte praticada no Pantanal é exercida de forma extensiva, com baixo padrão tecnológico em algumas propriedades, portanto considerada como grande emissora de Gases de Efeito Estufa, que podem ser reduzidos com a adoção de tecnologias disponíveis e indicadas pela Embrapa Pantanal para a região. O Pantanal é caracterizado pela alternância de estações seca e cheia e pela peculiaridade das suas pastagens nativas e demais recursos naturais tornando a bovinocultura de corte, na fase de cria, a sua principal atividade econômica. A região tem condições de produzir bezerros com baixo custo, apesar da maior parte das propriedades possuírem custo de produção alto devido a índices zootécnicos serem relativamente baixos. A atividade pecuária é relatada na região pantaneira desde 1737, sendo uma atividade econômica consolidada. Neste sentido, é preciso observar a sua importância dentro do contexto da pecuária do MS devido a complementaridade que a região pantaneira tem com outras regiões onde se pratica a recria e engorda. Isso propicia maiores vantagens competitivas dentro da cadeia de produção da bovinocultura de corte do Estado. Comparando as produtividades em kg de carne por hectare por ano nos sistemas de produção hoje existentes, tradicional (20 kg/hectare/ano) e melhorado (70 kg/hectare/ano), o impacto positivo no número de bezerros que podem ser produzidos e comercializados no Pantanal, nas condições melhoradas, complementa o sistema de engorda até o abate em toda a região. Esta perspectiva ganha força a medida que inúmeras áreas, antes ocupadas com atividades de cria no planalto, estão sendo cada vez mais ocupadas por outras atividades agrícolas. Percebe-se a importância da incorporação das tecnologias preconizadas pela Embrapa Pantanal para obtenção de maiores produtividades na pecuária de corte local com consequente aumento do número de crias por vacas ao longo da sua vida útil (ABREU et al., 2006a, 2006b; ABREU et al., 2008). Isso irá contribuir para uma maior eficiência e sustentabilidade da exploração pecuária no Estado de MS. Para se atingir este grande objetivo e ao mesmo tempo pautá-lo dentro dos princípios da sustentabilidade ambiental, temos o grande desafio de ampliar de forma sistemática a adoção das tecnologias recomendadas pela Embrapa para o Programa ABC na região do Pantanal. Com o intuito de adequação das tecnologias e aplicação correta dos recursos disponibilizados para o Programa o monitoramento das ações do ABC, missão que foi delegada à Embrapa, estabeleceu-se uma parceria entre a Embrapa Pantanal, o Banco do Brasil (BB), Ministério da Agricultura, Pecuária e Abastecimento (MAPA), Secretaria de Desenvolvimento Agrário, da Produção, da Industria, do Comercio e do Turismo do Estado de Mato Grosso do Sul (SEPROTUR) e Instituto do Meio Ambiente de Mato Grosso do Sul (IMASUL), tendo sido realizadas reuniões com a participação de agentes de crédito, produtores, e técnicos das firmas de planejamento e assistência técnica (ATEs) As tecnologias apresentadas pela Embrapa Pantanal que vão ao encontro dos objetivos do Programa ABC baseiam-se principalmente no aumento da eficiência do uso das áreas e do sistema de produção da pecuária de corte pantaneira, na redução da emissão de GEEs, no aumento da renda dos produtores, na diminuição da pressão para abertura de novas áreas (desmatamentos) e elevação da fixação de CO2 na vegetação e no solo. Este documento tem a finalidade de apresentar as tecnologias propostas pela Embrapa Pantanal em atendimento ao Plano ABC, bem como os parâmetros e os procedimentos operacionais para a elaboração e analise dos projetos, contratação e operacionalização dos contratos.bitstream/item/126070/1/DOC132.pd

Stratification of the orbit space in gauge theories. The role of nongeneric strata

Gauge theory is a theory with constraints and, for that reason, the space of physical states is not a manifold but a stratified space (orbifold) with singularities. The classification of strata for smooth (and generalized) connections is reviewed as well as the formulation of the physical space as the zero set of a momentum map. Several important features of nongeneric strata are discussed and new results are presented suggesting an important role for these strata as concentrators of the measure in ground state functionals and as a source of multiple structures in low-lying excitations.Comment: 22 pages Latex, 1 figur

Exercise training in the aerobic/anaerobic metabolic transition prevents glucose intolerance in alloxan-treated rats

<p>Abstract</p> <p>Background</p> <p>Ninety percent of cases of diabetes are of the slowly evolving non-insulin-dependent type, or Type 2 diabetes. Lack of exercise is regarded as one of the main causes of this disorder. In this study we analyzed the effects of physical exercise on glucose homeostasis in adult rats with type 2 diabetes induced by a neonatal injection of alloxan.</p> <p>Methods</p> <p>Female Wistar rats aged 6 days were injected with either 250 mg/kg of body weight of alloxan or citrate buffer 0.01 M (controls). After weaning, half of the animals in each group were subjected to physical training adjusted to meet the aerobic-anaerobic metabolic transition by swimming 1 h/day for 5 days a week with weight overloads. The necessary overload used was set and periodically readjusted for each rat through effort tests based on the maximal lactate steady state procedure. When aged 28, 60, 90, and 120 days, the rats underwent glucose tolerance tests (GTT) and their peripheral insulin sensitivity was evaluated using the HOMA index.</p> <p>Results</p> <p>The area under the serum glucose curve obtained through GTT was always higher in alloxan-treated animals than in controls. A decrease in this area was observed in trained alloxan-treated rats at 90 and 120 days old compared with non-trained animals. At 90 days old the trained controls showed lower HOMA indices than the non-trained controls.</p> <p>Conclusion</p> <p>Neonatal administration of alloxan induced a persistent glucose intolerance in all injected rats, which was successfully counteracted by physical training in the aerobic/anaerobic metabolic transition.</p

Protecting High Energy Barriers: A New Equation to Regulate Boost Energy in Accelerated Molecular Dynamics Simulations

Molecular dynamics (MD) is one of the most common tools in computational chemistry. Recently, our group has employed accelerated molecular dynamics (aMD) to improve the conformational sampling over conventional molecular dynamics techniques. In the original aMD implementation, sampling is greatly improved by raising energy wells below a predefined energy level. Recently, our group presented an alternative aMD implementation where simulations are accelerated by lowering energy barriers of the potential energy surface. When coupled with thermodynamic integration simulations, this implementation showed very promising results. However, when applied to large systems, such as proteins, the simulation tends to be biased to high energy regions of the potential landscape. The reason for this behavior lies in the boost equation used since the highest energy barriers are dramatically more affected than the lower ones. To address this issue, in this work, we present a new boost equation that prevents oversampling of unfavorable high energy conformational states. The new boost potential provides not only better recovery of statistics throughout the simulation but also enhanced sampling of statistically relevant regions in explicit solvent MD simulations

Transiting exoplanets from the CoRoT space mission VIII. CoRoT-7b: the first Super-Earth with measured radius

We report the discovery of very shallow (DF/F = 3.4 10-4), periodic dips in the light curve of an active V = 11.7 G9V star observed by the CoRoT satellite, which we interpret as due to the presence of a transiting companion. We describe the 3-colour CoRoT data and complementary ground-based observations that support the planetary nature of the companion. Methods. We use CoRoT color information, good angular resolution ground-based photometric observations in- and out- of transit, adaptive optics imaging, near-infrared spectroscopy and preliminary results from Radial Velocity measurements, to test the diluted eclipsing binary scenarios. The parameters of the host star are derived from optical spectra, which were then combined with the CoRoT light curve to derive parameters of the companion. We examine carefully all conceivable cases of false positives, and all tests performed support the planetary hypothesis. Blends with separation larger than 0.40 arcsec or triple systems are almost excluded with a 8 10-4 risk left. We conclude that, as far as we have been exhaustive, we have discovered a planetary companion, named CoRoT-7b, for which we derive a period of 0.853 59 +/- 3 10-5 day and a radius of Rp = 1.68 +/- 0.09 REarth. Analysis of preliminary radial velocity data yields an upper limit of 21 MEarth for the companion mass, supporting the finding. CoRoT-7b is very likely the first Super-Earth with a measured radius.Comment: Accepted in Astronomy and Astrophysics; typos and language corrections; version sent to the printer w few upgrade

The Genetic Structure of Leishmania infantum Populations in Brazil and Its Possible Association with the Transmission Cycle of Visceral Leishmaniasis

Leishmania infantum is the etiologic agent of visceral leishmaniasis (VL) in the Americas, Mediterranean basin and West and Central Asia. Although the geographic structure of L. infantum populations from the Old World have been described, few studies have addressed the population structure of this parasite in the Neotropical region. We employed 14 microsatellites to analyze the population structure of the L. infantum strains isolated from humans and dogs from most of the Brazilian states endemic for VL and from Paraguay. The results indicate a low genetic diversity, high inbreeding estimates and a depletion of heterozygotes, which together indicate a predominantly clonal breeding system, but signs of sexual events are also present. Three populations were identified from the clustering analysis, and they were well supported by F statistics inferences and partially corroborated by distance-based. POP1 (111 strains) was observed in all but one endemic area. POP2 (31 strains) is also well-dispersed, but it was the predominant population in Mato Grosso (MT). POP3 (31 strains) was less dispersed, and it was observed primarily in Mato Grosso do Sul (MS). Strains originated from an outbreak of canine VL in Southern Brazil were grouped in POP1 with those from Paraguay, which corroborates the hypothesis of dispersal from Northeastern Argentina and Paraguay. The distribution of VL in MS seems to follow the west-east construction of the Bolivia-Brazil pipeline from Corumbá municipality. This may have resulted in a strong association of POP3 and Lutzomyia cruzi, which is the main VL vector in Corumbá, and a dispersion of this population in this region that was shaped by human interference. This vector also occurs in MT and may influence the structure of POP2. This paper presents significant advances in the understanding of the population structure of L. infantum in Brazil and its association with eco-epidemiological aspects of VL

Frequency and Risk Indicators of Tooth Decay among Pregnant Women in France: A Cross-Sectional Analysis

INTRODUCTION: Little is known on the prevalence of tooth decay among pregnant women. Better knowledge of tooth decay risk indicators during pregnancy could help to develop follow-up protocols for women at risk, along with better prevention strategies. The aim of this study was to assess the frequency of tooth decay and the number of decayed teeth per woman in a large sample of pregnant women in France, and to study associated risk indicators. METHODS: A secondary cross-sectional analysis of data from a French multicentre case-control study was performed. The sample was composed of 1094 at-term women of six maternity units. A dental examination was carried out within 2 to 4 days post-partum. Socio-demographic and behavioural characteristics were obtained through a standardised interview with the women. Medical characteristics were obtained from the women's medical records. Risk indicators associated with tooth decay were identified using a negative binomial hurdle model. RESULTS: 51.6% of the women had tooth decay. The mean number of decayed teeth among women having at least one was 3.1 (s.d. = 2.8). Having tooth decay was statistically associated with lower age (aOR = 1.58, 95%CI [1.03,2.45]), lower educational level (aOR = 1.53, 95%CI [1.06,2.23]) and dental plaque (aOR = 1.75, 95%CI [1.27,2.41]). The number of decayed teeth was associated with the same risk indicators and with non-French nationality and inadequate prenatal care. DISCUSSION: The frequency of tooth decay and the number of decayed teeth among pregnant women were high. Oral health promotion programmes must continue to inform women and care providers about the importance of dental care before, during and after pregnancy. Future research should also assess the effectiveness of public policies related to oral health in target populations of pregnant women facing challenging social or economic situations