1,595 research outputs found

    Effectiveness evaluation of STOL transport operations

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    A short-takeoff and landing (STOL) systems simulation model has been developed and implemented in a computer code (known as STOL OPS) which permits evaluation of the operation of a STOL aircraft and its avionics in a commercial airline operating environment. STOL OPS concentrated on the avionics functions of navigation, guidance, control, communication, hazard aviodance, and systems management. External world factors influencing the operation of the STOL aircraft include each airport and its geometry, air traffic at each airport, air traffic control equipment and procedures, weather (including winds and visibility), and the flight path between each airport served by the route. The development of the STOL OPS program provides NASA a set of computer programs which can be used for detailed analysis of a STOL aircraft and its avionics and permit establishment of system requirements as a function of airline mission performance goals

    Fungal Peptaibiotics: Assessing Potential Meteoritic Amino Acid Contamination

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    The presence of non-protein alpha-dialkyl-amino acids such as alpha-aminoisobutyric acid (alpha-A1B) and isovaline (Iva), which are relatively rare in the terrestrial biosphere, has long been used as an indication of the indigeneity of meteoritic amino acids, however, the discovery of alpha-AIB in peptides producers by a widespread group of filamentous fungi indicates the possibility of a terrestrial biotic source for the alpha-AIB observed in some meteorites. The alpha-AIB-containing peptides produced by these fungi are dubbed peptaibiotics. We measured the molecular distribution and stable carbon and nitrogen isotopic ratios for amino acids found in the total hydrolysates of four biologically synthesized peptaibiotics. We compared these aneasurenetts with those from the CM2 carbonaceous chondrite Murchison and from three Antarctic CR2 carbonaceous chondrites in order to understand the peptaibiotics as a potential source of meteoritic contamination

    Ileal Adenocarcinoma with Liver Metastasis in Patient with Crohn\u27s Disease: A 9-Year Survival.

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    Small bowel adenocarcinoma is a rare but well-known complication of Crohn\u27s disease. The diagnosis of small bowel adenocarcinoma remains difficult since its presentation is highly variable and mimics active or obstructive Crohn\u27s disease. The diagnosis is often delayed and typically detected only at surgery in an advanced stage with a poor prognosis. We report a case of metastatic ileal adenocarcinoma in a patient with Crohn\u27s disease with prolonged survival. Our case describes serial promising treatment options of these advanced malignancies and raises a possible role for checkpoint immunotherapy

    Calculation of coercivity of magnetic nanostructures at finite temperatures

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    We report a finite temperature micromagnetic method (FTM) that allows for the calculation of the coercive field of arbitrary shaped magnetic nanostructures at time scales of nanoseconds to years. Instead of directly solving the Landau-Lifshitz-Gilbert equation, the coercive field is obtained without any free parameter by solving a non linear equation, which arises from the transition state theory. The method is applicable to magnetic structures where coercivity is determined by one thermally activated reversal or nucleation process. The method shows excellent agreement with experimentally obtained coercive fields of magnetic nanostructures and provides a deeper understanding of the mechanism of coercivity.Comment: submitted to Phys. Rev.

    Detecção molecular do Cowpea aphid-borne mosaic vírus (CABMV) em Passiflora edulis

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    A ocorrência de doenças é um dos principais problemas da cultura do maracujazeiro (Passiflora edulis Sims.) que podem ser limitantes à produção. O endurecimento dos frutos do maracujazeiro é considerada a virose mais importante da cultura do maracujá e é causada pelo Cowpea afhidborne mosaic virus (CABMV), pertencente à família Potyviridae e do gênero Potyvirus

    On the Lebesgue measure of Li-Yorke pairs for interval maps

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    We investigate the prevalence of Li-Yorke pairs for C2C^2 and C3C^3 multimodal maps ff with non-flat critical points. We show that every measurable scrambled set has zero Lebesgue measure and that all strongly wandering sets have zero Lebesgue measure, as does the set of pairs of asymptotic (but not asymptotically periodic) points. If ff is topologically mixing and has no Cantor attractor, then typical (w.r.t. two-dimensional Lebesgue measure) pairs are Li-Yorke; if additionally ff admits an absolutely continuous invariant probability measure (acip), then typical pairs have a dense orbit for f×ff \times f. These results make use of so-called nice neighborhoods of the critical set of general multimodal maps, and hence uniformly expanding Markov induced maps, the existence of either is proved in this paper as well. For the setting where ff has a Cantor attractor, we present a trichotomy explaining when the set of Li-Yorke pairs and distal pairs have positive two-dimensional Lebesgue measure.Comment: 41 pages, 3 figure

    Substratos no desenvolvimento inicial de quatro cultivares de pessegueiro e uma nectarineira.

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    Entre os fatores que contribuem para melhor desenvolvimento inicial das plantas, estão a qualidade da semente e o substrato utilizado.Objetivou-se avaliar o efeito do substrato na formação inicial de pessegueiro e nectarineira. O trabalho foi realizado no Departamento de Fitotecnia, da Universidade Federal de Viçosa, de fevereiro a março de 2004. Foram utilizados quatro cultivares de pessegueiro, 'Alô Doçura', 'Campinas 1', 'Relíquia' e 'Ouromel' e uma cultivar de nectarineira 'Josefina'. Sementes retiradas de frutos maturos, foram estratificadas em câmara fria, com temperatura de 5±1ºC e ausência de luz. Após a germinação, no interior da casa-de-vegetação, procedeu-se à semeadura em recipientes plásticos (3 litros), contendo os substratos: Plantmax®; Plantmax® + Areia (1:1 v/v); Plantmax® + Latossolo Vermelho (1:1 v/v); Plantmax® + Latossolo Vermelho + Areia (1:1:1 v/v). Foi utilizado o delineamento experimental inteiramente casualizado, num fatorial 5 x 4 (cultivar x substrato), com cinco repetições, considerando-se como unidade experimental cada recipiente plástico. Após 38 dias da semeadura foram analisadas: porcentagem de emergência, número de folhas, comprimento total, altura e comprimento de raiz, diâmetro do caule, massa da matéria seca total, da parte aérea e da raiz e o número de brotações primárias. O substrato teve efeito no desenvolvimento inicial de pessegueiro, obtendo-se os melhores resultados com o substrato comercial Plantmax®. O maior acúmulo de massa de matéria seca total e da parte aérea foi obtido com os cultivares 'Campinas 1' e 'Relíquia', sendo que esse último, também proporcionou maior número de brotações primárias

    Ácido giberélico no crescimento inicial de mudas de pessegueiro.

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    O emprego de certas práticas culturais são fundamentais para obtenção de mudas de qualidade, com reduzido período de formação. Realizou-se, este trabalho, em casa de vegetação, no Departamento de Fitotecnia da Universidade Federal de Viçosa, com o objetivo de avaliar o efeito de cinco concentrações de ácido giberélico (GA3) (0; 50; 100; 150 e 200 mg L-1), no crescimento inicial do pessegueiro. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições, considerando-se como unidade experimental, os quatro recipientes plásticos contendo uma planta cada. Foram realizadas três aplicações de GA3 (60, 80 e 100 dias de cultivo). Nas aplicações, a parte aérea foi molhada inteiramente, utilizando-se 20 ml de solução para cada planta. Aos 130 dias da semeadura, foram analisados: comprimento da parte aérea e da raiz; diâmetro do caule; número de brotações primárias; massa da matéria seca da parte aérea e da raiz. Concluiu-se que o ácido giberélico exerceu efeito sobre o crescimento de pessegueiro, recomendando-se a pulverização de 200 mg L-1. As pulverizações de GA3 não tiveram efeito sobre o diâmetro do caule do pessegueiro

    How U.S. Ocean Policy and Market Power Can Reform the Coral Reef Wildlife Trade

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    As the world’s largest importer of marine ornamental species for the aquaria, curio, home décor, and jewelry industries, the United States has an opportunity to leverage its considerable market power to promote more sustainable trade and reduce the effects of ornamental trade stress on coral reefs worldwide. Evidence indicates that collection of some coral reef animals for these trades has caused virtual elimination of local populations, major changes in age structure, and promotion of collection practices that destroy reef habitats. Management and enforcement of collection activities in major source countries such as Indonesia and the Philippines remain weak. Strengthening US trade laws and enforcement capabilities combined with increasing consumer and industry demand for responsible conservation can create strong incentives for improving management in source countries. This is particularly important in light of the March 2010 failure of the parties to the Convention on International Trade in Endangered Species (CITES) to take action on key groups of corals
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