33 research outputs found

    Advantages of a Modular Mars Surface Habitat Approach

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    Early crewed Mars mission concepts developed by the National Aeronautics and Space Administration (NASA) assumed a single, large habitat would house six crew members for a 500-day Mars surface stay. At the end of the first mission, all surface equipment, including the habitat, -would be abandoned and the process would be repeated at a different Martian landing site. This work was documented in a series of NASA publications culminating with the Mars Design Reference Mission 5.0 (NASA-SP-2009-566). The Evolvable Mars Campaign (EMC) explored whether re-using surface equipment at a single landing site could be more affordable than the Apollo-style explore-abandon-repeat mission cadence. Initial EMC assumptions preserved the single, monolithic habitat, the only difference being a new requirement to reuse the surface habitat for multiple expedition crews. A trade study comparing a single large habitat versus smaller, modular habitats leaned towards the monolithic approach as more mass-efficient. More recent work has focused on the operational aspects of building up Mars surface infrastructure over multiple missions, and has identified compelling advantages of the modular approach that should be considered before making a final decision. This paper explores Mars surface mission operational concepts and integrated system analysis, and presents an argument for the modular habitat approach

    New methods and equipment of decametric radio astronomy for continuum observation at the UTR-2 radio telescope

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    At present time the modernization of the giant decametric radio telescope UTR-2 is under way. New back-end facilities and methods which open up new possibilities for radio astronomical observations are developed. Some equipment was made in cooperation with Austrian and French radio astronomers. Current back-end facilities and methods used at the UTR-2 radio telescope are described and compared with former traditional methods, equipment and their characteristics. Some prospects regarding current progress in developing new generation of back-end facilities are also discussed. The main focus of the presentation is the observation methods and equipment applied at the UTR-2 radio telescope for the investigation of continuum radio sources: Galactic background, discrete sources (preparation for the catalogue of sources in the whole Northern Sky), SNR, HII regions. Some results of using the new back-end facilities (such as Digital Spectral Polarimeter) and processing methods are presented

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

    Níveis nutricionais de cobre para frangos de corte machos e fêmeas na fase inicial Copper nutritional levels for male and female broilers in the initial phases

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    Com o objetivo de determinar a exigência de cobre (Cu) para frangos de corte na fase inicial (8 - 21 dias), foram utilizadas 384 aves, metade machos e metade fêmeas. Foi elaborada uma dieta basal atendendo às exigências nutricionais das aves, com exceção do Cu, que ficou deficiente, com nível de 1,47 ppm. Os tratamentos consistiram dos níveis de suplementação de Cu provenientes do sulfato de Cu, resultando em um total de 1,47; 4,97; 8,47; 11,97; 15,47 e 18,97 ppm de Cu na dieta. Foram avaliados o ganho de peso, o consumo de ração, a conversão alimentar e a concentração de Cu no osso, no fígado e no soro. Os níveis de Cu estudados influenciaram o consumo de ração, mas não influenciaram o ganho de peso e a conversão alimentar. Não houve efeito dos níveis de Cu sobre a concentração deste mineral no osso. Observou-se efeito dos níveis de Cu da dieta sobre suas concentrações no fígado e no soro, respectivamente. No entanto, optou-se pelo valor de exigência estimado pela variável Cu no soro, por representar melhor o status nutricional de Cu no organismo animal. Concluiu-se, portanto, que a exigência de Cu para frangos de corte, machos e fêmeas, de 8 a 21 dias de idade é de 9,48 ppm, ressaltando-se que dietas práticas de frangos de corte à base de milho e farelo de soja contêm normalmente de 8,5 a 11 ppm de Cu e que a biodisponibilidade do Cu no farelo de soja é de 38%.<br>Three hundred and eighty-four birds, half males and half females, were used to determine the copper (Cu) requirement for broilers in the initial phase (from 8 to 21 days). A basal diet was formulated to meet the bird nutritional requirements, except for Cu, that was deficient at 1.47 ppm level. The treatments consisted of Cu supplementation levels, from Cu sulfate, in a total of 1.47, 4.97, 8.47, 11.97, 15.47 and 18.97 ppm Cu in the diet. Weight gain, feed intake, feed:gain ratio and Cu concentration in the bone, liver and serum were evaluated. The studied Cu levels affected feed intake, but did not alter weight gain and feed:gain ratio. No effects of Cu levels on Cu concentration in the bone were detected. Effects of increasing dietary Cu levels on Cu concentration in the liver and serum were observed. However, the most adequate value of Cu requirement was estimated in the serum, because it better represents the Cu nutricional status in the animal organism. It was concluded that Cu requirements for broilers, males and females, from 8 to 21 days old is of 9.48 ppm, considering that corn and soybean meal-based diets, for broilers, contain from 8.5 to 11 ppm Cu and that Cu bioavailability in the soybean meal of 38%
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