Detection of CO in Triton's atmosphere and the nature of surface-atmosphere interactions

Triton possesses a thin atmosphere, primarily composed of nitrogen, sustained by the sublimation of surface ices. The goal is to determine the composition of Triton's atmosphere and to constrain the nature of surface-atmosphere interactions. We perform high-resolution spectroscopic observations in the 2.32-2.37 $\mu$m range, using CRIRES at the VLT. From this first spectroscopic detection of Triton's atmosphere in the infrared, we report (i) the first observation of gaseous methane since its discovery in the ultraviolet by Voyager in 1989 and (ii) the first ever detection of gaseous CO in the satellite. The CO atmospheric abundance is remarkably similar to its surface abundance, and appears to be controlled by a thin, CO-enriched, surface veneer resulting from seasonal transport and/or atmospheric escape. The CH$_4$ partial pressure is several times larger than inferred from Voyager. This confirms that Triton's atmosphere is seasonally variable and is best interpreted by the warming of CH$_4$-rich icy grains as Triton passed southern summer solstice in 2000. The presence of CO in Triton's atmosphere also affects its temperature, photochemistry and ionospheric composition. An improved upper limit on CO in Pluto's atmosphere is also reported.Comment: 11 pages, including 4 figures and 2 on-line figures Astronomy and Astrophysics, in press (accepted March 13, 2010

Deficiency of the bone mineralization inhibitor NPP1 protects against obesity and diabetes

The emergence of bone as an endocrine regulator has prompted a re-evaluation of the role of bone mineralization factors in the development of metabolic disease. Ectonucleotide pyrophosphatase/phosphodiesterase-1 (NPP1) controls bone mineralization through the generation of pyrophosphate, and levels of NPP1 are elevated both in dermal fibroblast cultures and muscle of individuals with insulin resistance. We investigated the metabolic phenotype associated with impaired bone metabolism in mice lacking the gene that encodes NPP1 (Enpp1−/− mice). Enpp1−/− mice exhibited mildly improved glucose homeostasis on a normal diet but showed a pronounced resistance to obesity and insulin resistance in response to chronic high-fat feeding. Enpp1−/− mice had increased levels of the insulin-sensitizing bone-derived hormone osteocalcin but unchanged insulin signalling within osteoblasts. A fuller understanding of the pathways of NPP1 could inform the development of novel therapeutic strategies for treating insulin resistance

Características da madeira de Populus sp. e Platanus sp.

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Parasite intensity drives fetal development and sex allocation in a wild ungulate

Altres ajuts: Natural Sciences and Engineering Research Council of Canada 316189-2012-RGPIN. Beringian Coevolution Project (BCP), National Science Foundation DEB 0196095 i 0415668An understanding of the mechanisms influencing prenatal characteristics is fundamental to comprehend the role of ecological and evolutionary processes behind survival and reproductive success in animals. Although the negative influence of parasites on host fitness is undisputable, we know very little about how parasitic infection in reproductive females might influence prenatal factors such as fetal development and sex allocation. Using an archival collection of Dall's sheep (Ovis dalli dalli), a capital breeder that depends on its body reserves to overcome the arctic winter, we investigated the direct and indirect impacts of the parasite community on fetal development and sex allocation. Using partial least squares modelling, we observed a negative effect of parasite community on fetal development, driven primarily by the nematode Marshallagia marshalli. Principal component analysis demonstrated that mothers with low parasite burden and in good body condition were more likely to have female versus male fetuses. This association was primarily driven by the indirect effect of M. marshalli on ewe body condition. Refining our knowledge of the direct and indirect impact that parasite communities can have on reproduction in mammals is critical for understanding the effects of infectious diseases on wildlife populations. This can be particularly relevant for species living in ecosystems sensitive to the effects of global climate change

Dynamics of aerosol size during inhalation : Hygroscopic growth of commercial nebulizer formulations

We thank the Elizabeth Blackwell Institute (EBI) for financial support through the EBI Early Career Research Fellowship awarded to AEH, and the EPSRC for financial support through a Leadership Fellowship awarded to JPR (grant reference EP/G007713/1). This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are creditedThe size of aerosol particles prior to, and during, inhalation influences the site of deposition within the lung. As such, a detailed understanding of the hygroscopic growth of an aerosol during inhalation is necessary to accurately model the deposited dose. In the first part of this study, it is demonstrated that the aerosol produced by a nebulizer, depending on the airflows rates, may experience a (predictable) wide range of relative humidity prior to inhalation and undergo dramatic changes in both size and solute concentration. A series of sensitive single aerosol analysis techniques are then used to make measurements of the relative humidity dependent thermodynamic equilibrium properties of aerosol generated from four common nebulizer formulations. Measurements are also reported of the kinetics of mass transport during the evaporation or condensation of water from the aerosol. Combined, these measurements allow accurate prediction of the temporal response of the aerosol size prior to and during inhalation. Specifically, we compare aerosol composed of pure saline (150 mM sodium chloride solution in ultrapure water) with two commercially available nebulizer products containing relatively low compound doses: Breath, consisting of a simple salbutamol sulfate solution (5 mg/2.5 mL; 1.7 mM) in saline, and Flixotide Nebules, consisting of a more complex stabilized fluticasone propionate suspension (0.25 mg/mL; 0.5 mM in saline. A mimic of the commercial product Tobi (60 mg/mL tobramycin and 2.25 mg/mL NaC1, pH 5.5-6.5) is also studied, which was prepared in house. In all cases, the presence of the pharmaceutical was shown to have a profound effect on the magnitude, and in some cases the rate, of the mass flux of water to and from the aerosol as compared to saline. These findings provide physical chemical evidence supporting observations from human inhalation studies, and suggest that using the growth dynamics of a pure saline aerosol in a lung inhalation model to represent nebulizer formulations may not be representative of the actual behavior of the aerosolized drug solutions. (C) 2014 Published by Elsevier B.V.Peer reviewe

A utilização de serrarias portáteis em florestas de pinus e eucaliptos em pequenas propriedades rurais: a experiência da Embrapa/Cotrel.

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Stability of negative central magnetic shear discharges in the DIII-D tokamak

Discharges with negative central magnetic shear (NCS) hold the promise of enhanced fusion performance in advanced tokamaks. However, stability to long wavelength magnetohydrodynamic modes is needed to take advantage of the improved confinement found in NCS discharges. The stability limits seen in DIII-D experiments depend on the pressure and current density profiles and are in good agreement with stability calculations. Discharges with a strongly peaked pressure profile reach a disruptive limit at low beta, {beta}{sub N} = {beta} (I/aB){sup -1} {le} 2.5 (% m T/MA), caused by an n = 1 ideal internal kink mode or a global resistive instability close to the ideal stability limit. Discharges with a broad pressure profile reach a soft beta limit at significantly higher beta, {beta}{sub N} = 4 to 5, usually caused by instabilities with n > 1 and usually driven near the edge of the plasma. With broad pressure profiles, the experimental stability limit is independent of the magnitude of negative shear but improves with the internal inductance, corresponding to lower current density near the edge of the plasma. Understanding of the stability limits in NCS discharges has led to record DIII-D fusion performance in discharges with a broad pressure profile and low edge current density

Diagnóstico da produção e comercialização de plantios florestais na região do Alto Uruguai, RS.

O presente trabalho teve como objetivo ampliar o conhecimento dos produtores, pesquisadores e da resistência técnica sobre a oferta da produção de florestas implantadas entre os anos de 1993 a 1998 e o comportamento da demanda atual de produtos e subprodutos florestais na região do Alto Uruguai do Rio Grande do Sul. Ele visa fornecer subsídios a novas estratégias de utilização e ampliação dos reflorestamentos naquela região. O estudo foi baseado em 200 questionários aplicados a produtores rurais que implantaram florestas e 100 a agroindústria e comerciantes de florestas, em 19 municípios da região. De 1993 a 1998, 90% das mudas comercializadas pela COTREL foram de pinus e eucaliptos, possibilitando a implantação de 3.152 hectares de floresta, ou seja, 525, 3 ha/ano, dos quais 84,4% com eucalipto. Há perdas médias estimadas de 30% das mudas plantadas. As ofertas de matéria prima proveniente dos reflorestamentos com eucalipto e pinus foram estimadas considerando regimes de manejos visando produção de toras para serraria. Assim, considerando que os reflorestamentos vêm sendo desbastados, foi simulado mais de um desbaste aos 14 anos e corte final aos 21 anos. A demanda de matéria prima em 1999, estima em 175.000m(cúbicos), indica a necessidade de corte de 7 mil hectares por ano, que é 12 vezes maior do que tem sido palmito com a oferta anual de mudas pela COTREL. Por outro lado, um melhor aproveitamento dos reflorestamentos implantados pode ser obtido com a implantação de serrarias portáteis, por exemplo, com capacidade de processar 1.800m (cúbicos) por ano, nove poderiam estar operando a partir de 2007 na região. Pode-se projetar, ainda, até cem serrarias a partir de 2014. A matéria prima adquirida pelo setor agroindustrial e comercial do Alto Uruguai tem 75% de sua origem na região do Alto Uruguai e provém dos estados de Mato Grosso (5,7%) , Paraná (4,8%), Santa Catarina (14,5%). A tendência dos agroindústria e comerciantes quanto ao futuro em sua maioria, prevêem o crescimento. Entre os problemas relevantes levantados pode-se verificar como o mais importante a questão que envolve a qualidade de matéria prima, em 26%. Há pequena conscientização dos produtores para os diferentes usos de florestas plantadas. Os gastos anuais dos produtores na compra de madeira foram estimados em 470,00 em 1998 e R$ 345,00 em 1999, por propriedade. O uso de uma serraria móvel na região pode gerar dois empregos fixos e as taxa interna de retorno é de 18% ao ano. O uso de mão-de-obra foi estimado em 7 empregados por empresa agroindustrial. mas, há predominância de pequenas fábricas familiares de móveis. A perda da cultura florestal pelos produtores, a necessidade de manutenção do fluxo financeiro familiar, no curto prazo, falta de conhecimento do mercado para produtos e subprodutos oriundos da madeira, diminui o interesse pela produção florestal na região.bitstream/item/17061/1/doc51.pd

Produção e comercialização de madeira de plantios florestais na região do Alto Uruguai, RS.

Edição especial de Erva-mate