248 research outputs found

    Human factors in space telepresence

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    The problems of interfacing a human with a teleoperation system, for work in space are discussed. Much of the information presented here is the result of experience gained by the M.I.T. Space Systems Laboratory during the past two years of work on the ARAMIS (Automation, Robotics, and Machine Intelligence Systems) project. Many factors impact the design of the man-machine interface for a teleoperator. The effects of each are described in turn. An annotated bibliography gives the key references that were used. No conclusions are presented as a best design, since much depends on the particular application desired, and the relevant technology is swiftly changing

    Optimization of 4-amino-pyridazin-3(2H)-one as a valid core scaffold for FABP4 inhibitors

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    Current clinical research suggests that fatty acid-binding protein 4 inhibitors (FABP4is), which are of biological and therapeutic interest, may show potential in treating cancer and other illnesses. We sought to uncover new structures through the optimization of the previously reported 4-amino and 4-ureido pyridazinone-based series of FABP4is as part of a larger research effort to create more potent FABP4 inhibitors. This led to the identification of 14e as the most potent analog with IC₅₀ = 1.57 μM, which is lower than the IC₅₀ of the positive control. Advanced modeling investigations and in silico absorption, distribution, metabolism, and excretion - toxicity calculations suggested that 14e represents a potential candidate for in vivo studies such as FABP4i

    Avaliação da casca de mamona na alimentação de ovinos.

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    Resumo: Objetivou-se com este trabalho, avaliar a casca de mamona na alimentação de ovinos. Foram utilizadas quatro fêmeas ovinas jovens, sem raça definida, com peso vivo médio de 30 kg e idade média de sete meses. Os animais foram mantidos em gaiolas de metabolismo e distribuídos em um delineamento em quadrado latino 4 x 4 para avaliar o efeito de quatro níveis de inclusão da casca de mamona em substituição ao milho em dietas isoprotéicas e isoenergéticas. Como alimento volumoso foi utilizado o feno de capim-Tifton, mantendo uma relação volumoso:concentrado de 60:40. Cada período experimental teve duração de 21 dias, sendo 14 dias de adaptação e sete dias de coleta de dados. Foram mensuradas as seguintes variáveis: a composição bromatológica e o valor de energia da casca de mamona, o consumo voluntário, a digestibilidade da matéria seca e de nutrientes e o balanço de nitrogênio. Houve uma redução no consumo da matéria seca e na digestibilidade da matéria orgânica com o aumento na participação da casca de mamona (P < 0,05). Com a substituição de 72,92% do milho por casca de mamona, houve também uma redução significativa da digestibilidade da fibra (P < 0,05). Não houve efeito dos tratamentos sobre o balanço de nitrogênio (P < 0,05), nem sintomas de intoxicação nos animais. A casca de mamona com 13% de sementes em sua composição, não apresentam efeitos tóxicos em níveis de até 15,25% da matéria seca da dieta, sendo um alimento com potencial de uso em dietas para pequenos ruminantes. [Castor bean hulls in the female sheep diets]. Abstract - This experiment was assigned to evaluate the castor bean hulls in the sheep feeding Four 7 month old young females, weighting 30 kg were used. They were set in metabolic cages and distributed in a 4 x 4 Latin Square design to evaluate the effect of four levels of castor bean hulls inclusion in substitution of corn grain diets. Bermudagrass hay was the forage used, maintaining a roughage:concentrate ratio 60:40. Each experimental period had duration of 21 days, being 14 days of adaptation and 7 days of data collection. The variables evaluated were: bromatologic composition and energy value of castor bean hulls, voluntary feed intake, dry matter and nutrients digestibility and nitrogen balance. There was a reduction in dry matter intake and in digestibility of organic matter with the increasing participation of castor bean hulls (P < 0.05). When the substitution from corn grain to castor bean hulls achieved 72.92%, there was also a significant reduction in fiber digestibility (P < 0.05). On the other hand, there was not effect of the treatments on nitrogen balance (P < 0.05) and did not occur intoxication symptoms in the animals. The castor bean hulls, with 13% of seed in their composition, did not present toxic effect in levels up to 15.25% of the dry matter, being a potential food source to be used in small ruminant diets

    Geoestatística aplicada aos atributos físicos e químicos do solo relacionados com a produção da cultura da soja.

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    A combinação de dados espacialmente distribuídos da produção agrícola, como os de produtividade e atributos do solo, constitui importante ferramenta de diagnóstico para uso mais eficiente das informações, possibilitando melhor manejo da variabilidade no campo. O objetivo do presente trabalho foi analisar a variabilidade espacial dos atributos físicos e químicos do solo e da produtividade da soja por meio da análise geoestatística, com o intuito de colaborar com a avaliação da qualidade do solo no Município de Campinas, SP. Os dados foram obtidos por meio de amostragem em 50 pontos georreferenciados: atributos físicos (densidade do solo e infiltração de água no solo) e químicos (pH, soma de bases e saturação por bases) e a produtividade da soja foram submetidos à análise de dependência espacial. A análise geoestatística possibilitou a identificação da variabilidade espacial de alguns atributos físicos e químicos do solo e da produtividade de soja. Mapas de isolinhas permitiram estabelecer relações entre os atributos físicos e químicos do solo. Houve semelhanças quanto aos locais de melhor fertilidade do solo em relação aos valores de pH e saturação por bases de 10-20 cm e maiores valores de produtividade da soja. Em relação aos atributos físicos, esta relação não foi detectada espacialmente

    Spectroscopy of 18^{18}Na: Bridging the two-proton radioactivity of 19^{19}Mg

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    The unbound nucleus 18^{18}Na, the intermediate nucleus in the two-proton radioactivity of 19^{19}Mg, was studied by the measurement of the resonant elastic scattering reaction 17^{17}Ne(p,17^{17}Ne)p performed at 4 A.MeV. Spectroscopic properties of the low-lying states were obtained in a R-matrix analysis of the excitation function. Using these new results, we show that the lifetime of the 19^{19}Mg radioactivity can be understood assuming a sequential emission of two protons via low energy tails of 18^{18}Na resonances

    Cooperation, Norms, and Revolutions: A Unified Game-Theoretical Approach

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    Cooperation is of utmost importance to society as a whole, but is often challenged by individual self-interests. While game theory has studied this problem extensively, there is little work on interactions within and across groups with different preferences or beliefs. Yet, people from different social or cultural backgrounds often meet and interact. This can yield conflict, since behavior that is considered cooperative by one population might be perceived as non-cooperative from the viewpoint of another. To understand the dynamics and outcome of the competitive interactions within and between groups, we study game-dynamical replicator equations for multiple populations with incompatible interests and different power (be this due to different population sizes, material resources, social capital, or other factors). These equations allow us to address various important questions: For example, can cooperation in the prisoner's dilemma be promoted, when two interacting groups have different preferences? Under what conditions can costly punishment, or other mechanisms, foster the evolution of norms? When does cooperation fail, leading to antagonistic behavior, conflict, or even revolutions? And what incentives are needed to reach peaceful agreements between groups with conflicting interests? Our detailed quantitative analysis reveals a large variety of interesting results, which are relevant for society, law and economics, and have implications for the evolution of language and culture as well

    Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action

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    Background Patterns of food intake and prevalent osteoarthritis of the hand, hip, and knee were studied using the twin design to limit the effect of confounding factors. Compounds found in associated food groups were further studied in vitro. Methods Cross-sectional study conducted in a large population-based volunteer cohort of twins. Food intake was evaluated using the Food Frequency Questionnaire; OA was determined using plain radiographs. Analyses were adjusted for age, BMI and physical activity. Subsequent in vitro studies examined the effects of allium-derived compounds on the expression of matrix-degrading proteases in SW1353 chondrosarcoma cells. Results Data were available, depending on phenotype, for 654-1082 of 1086 female twins (median age 58.9 years; range 46-77). Trends in dietary analysis revealed a specific pattern of dietary intake, that high in fruit and vegetables, showed an inverse association with hip OA (p = 0.022). Consumption of 'non-citrus fruit' (p = 0.015) and 'alliums' (p = 0.029) had the strongest protective effect. Alliums contain diallyl disulphide which was shown to abrogate cytokine-induced matrix metalloproteinase expression. Conclusions Studies of diet are notorious for their confounding by lifestyle effects. While taking account of BMI, the data show an independent effect of a diet high in fruit and vegetables, suggesting it to be protective against radiographic hip OA. Furthermore, diallyl disulphide, a compound found in garlic and other alliums, represses the expression of matrix-degrading proteases in chondrocyte-like cells, providing a potential mechanism of action
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