499 research outputs found
Human factors in space telepresence
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
Is the salivary gland associated with honey bee recognition compounds in worker honey bees (Apis mellifera)?
Cuticular hydrocarbons (CHCs) function as recognition compounds with the best evidence coming from social insects such as ants and honey bees. The major exocrine gland involved in hydrocarbon storage in ants is the post-pharyngeal gland (PPG) in the head. It is still not clearly understood where CHCs are stored in the honey bee. The aim of this study was to investigate the hydrocarbons and esters found in five major worker honey bee (Apis mellifera) exocrine glands, at three different developmental stages (newly emerged, nurse, and forager) using a high temperature GC analysis. We found the hypopharyngeal gland contained no hydrocarbons nor esters, and the thoracic salivary and mandibular glands only contained trace amounts of n-alkanes. However, the cephalic salivary gland (CSG) contained the greatest number and highest quantity of hydrocarbons relative to the five other glands with many of the hydrocarbons also found in the Dufour's gland, but at much lower levels. We discovered a series of oleic acid wax esters that lay beyond the detection of standard GC columns. As a bee's activities changed, as it ages, the types of compounds detected in the CSG also changed. For example, newly emerged bees have predominately C19-C23 n-alkanes, alkenes and methyl-branched compounds, whereas the nurses' CSG had predominately C31:1 and C33:1 alkene isomers, which are replaced by a series of oleic acid wax esters in foragers. These changes in the CSG were mirrored by corresponding changes in the adults' CHCs profile. This indicates that the CSG may have a parallel function to the PPG found in ants acting as a major storage gland of CHCs. As the CSG duct opens into the buccal cavity the hydrocarbons can be worked into the comb wax and could help explain the role of comb wax in nestmate recognition experiments
Direct and indirect orthotic management of medial compartment osteoarthritis of the knee
Osteoarthritis (OA) is a painful condition and affects approximately 80% of individuals by the age of 55 [1], with knee OA occurring two times more frequently than OA of the hand or hip [2].The condition is more prevalent in the medial compartment and restricts the daily lives of individuals due to pain and a lack of functional independence. Patients with medial compartment osteoarthritis often have a varus alignment, with the mechanical axis and load bearing passing through this compartment with a greater adduction moment leading to greater pain and progression of osteoarthritis [3]. Surgery for the condition is possible although in some cases, particularly younger patients or those not yet requiring surgery, clinical management remains a challenge. Before surgery is considered, however, conservative management is advocated, though no one treatment has been shown to be most effective, and there are few quality biomechanical or clinical studies. Of the conservative approaches the principal orthotic treatments are valgus knee braces and laterally wedged foot inlays. Studies of knee valgus bracing have consistently demonstrated an associated decreased pain and improved function [4], and greater confidence [5]. A laterally wedged foot inlay has a thicker lateral border and applies a valgus moment to the heel. It is theorised that by changing the position of the ankle and subtalar joints during weight-bearing [6] the lateral wedges may apply a valgus moment across the knee as well as the rearfoot, with the assumed reduction on load in the medial knee compartment [7]. However, there has been no study to directly compare these orthotic treatments in the same study. The aim of this research is to investigate the efficacy of valgus knee braces and laterally wedged foot inlays in reducing the varus knee moment
Estimation of genetic parameters and verification of early selection efficiency in baru (Dipteryx alata).
This study aimed at verifying the efficiency of early selection, and estimating the genetic parameters in Dipteryx alata. The 66 half-sib families were obtained from three seed provenances at the Brazilian Savannah of the state of Minas Gerais. The experiment was carried out in a randomized block design with 3 replications and 5 plants per plot. Data diameters at breast height (DBH) and total height (TH) were taken at the ages of 64, 125 and 138 months. REML/BLUP methodology was applied in the D. alata different provenances and progenies. Analysis indicated significant genetic variability (P < 0.01) between and within provenances. Both traits, DBH and TH, presented high narrow sense heritability for the ages analyzed. High genetic correlation occurred between DBH and TH traits, and between ages (age-age); thus, it allowed indirect selection, as well as early selection with high genetics gains
Avaliação clonal para identificação de matrizes promissoras de cupuaçuzeiro (Theobroma grandiflorum).
O cupuaçuzeiro, Theobroma grandiflorum (Willd. ex Spreng.) Schumm., é uma fruteira que, apesar da importância econômica que representa para a economia da região amazônica, sendo a segunda espécie frutícola mais importante com cerca de 10% do mercado de todas as frutas, ainda depende de ajustes no seu sistema produtivo. Entre as carências de pesquisa destaca-se a necessidade de materiais de plantação. Este trabalho teve por objetivo avaliar um conjunto de genótipos de cupuaçuzeiro, a fim de selecionar materiais promissores para o programa de melhoramento genético. O experimento foi conduzido em parceria com um produtor rural do município de Tomé Açu, no período de 2006 a 2011. A análise dos resultados do desenvolvimento vegetativo de todos os 25 clones, nos anos de 2006 a 2007, demonstrou que altura média das plantas foi de 1,6 m e o diâmetro do tronco ficou em 3,4 cm. Em relação ao número de frutos, a média do experimento, cresceu lentamente nas três primeiras safras, até atingir, na safra 2010/2011, a produção de 17,6 frutos/planta/safra. Dos 10 clones procedentes da fazenda do Sr. Inada, 8 (clones 7, 9, 6, 8, 10, 4, 11 e 5) encontram-se no grupo dos mais produtivos. Vale ressaltar que as cultivares Coari (174), Codajás (186) e Manacapuru (215) também fizeram parte desse seleto grupo. Nenhum clone foi afetado pela vassoura de bruxa nessa primeira etapa de avaliação.PIBIC-2011
Conservation Laws in Higher-Order Nonlinear Optical Effects
Conservation laws of the nonlinear Schr\"{o}dinger equation are studied in
the presence of higher-order nonlinear optical effects including the
third-order dispersion and the self-steepening. In a context of group theory,
we derive a general expression for infinitely many conserved currents and
charges of the coupled higher-order nonlinear Schr\"{o}dinger equation. The
first few currents and charges are also presented explicitly. Due to the
higher-order effects, conservation laws of the nonlinear Schr\"{o}dinger
equation are violated in general. The differences between the types of the
conserved currents for the Hirota and the Sasa-Satsuma equations imply that the
higher-order terms determine the inherent types of conserved quantities for
each integrable cases of the higher-order nonlinear Schr\"{o}dinger equation
Geoestatística aplicada aos atributos físicos e químicos do solo relacionados com a produção da cultura da soja.
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
Optimization of 4-amino-pyridazin-3(2H)-one as a valid core scaffold for FABP4 inhibitors
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.
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
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