981 resultados para Artificial potential fields


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The action of extracts from the stem, leaves, and fruit of Jatropha gossypiifolia on Biomphalaria glabrata was studied by analyzing survival, feeding capacity and oviposition ability. The extracts were obtained by macerating the plant parts in 92% ethanol, which were then evaporated until a dry residue was obtained and phytochemically studied. The molluscicidal activity on B. glabrata was investigated using the procedures recommended by WHO (1965). The amount of food ingested and oviposition were measured during each experiment. The extract of leaves from J. gossypiifolia was shown to be a strong molluscicidal agent, causing 100% mortality of B. glabrata, even in the lowest concentration tested, of 25 ppm. Regarding the fruit extract, there was variation in the mortality, depending on the concentration used (100, 75, 50 and 25 ppm). The snails that were in contact with the fruit extract had significant reduction in feeding and number of embryos in comparison to the control. The stem extract did not present molluscicidal activity nor had any influence on the feeding and oviposition abilities of B. glabrata, in the concentrations tested. In conclusion, the extracts of leaves and fruits of J. gossypiifolia investigated in this work show molluscicidal effect and may be sources of useful compounds for the schistosomiasis control.

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Neste documento, são investigados vários métodos usados na inteligência artificial, com o objetivo de obter previsões precisas da evolução dos mercados financeiros. O uso de ferramentas lineares como os modelos AR, MA, ARMA e GARCH têm muitas limitações, pois torna-se muito difícil adaptá-los às não linearidades dos fenómenos que ocorrem nos mercados. Pelas razões anteriormente referidas, os algoritmos como as redes neuronais dinâmicas (TDNN, NARX e ESN), mostram uma maior capacidade de adaptação a estas não linearidades, pois não fazem qualquer pressuposto sobre as distribuições de probabilidade que caracterizam estes mercados. O facto destas redes neuronais serem dinâmicas, faz com que estas exibam um desempenho superior em relação às redes neuronais estáticas, ou outros algoritmos que não possuem qualquer tipo de memória. Apesar das vantagens reveladas pelas redes neuronais, estas são um sistema do tipo black box, o que torna muito difícil extrair informação dos pesos da rede. Isto significa que estes algoritmos devem ser usados com precaução, pois podem tornar-se instáveis.

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Trichophyton rubrum and Trichophyton mentagrophytes complex, or Trichophyton spp. are the main etiologic agents of dermatophytosis, whose treatment is limited by the high cost of antifungal treatments, their various side effects, and the emergence of resistance amongst these species. This study evaluated the in vitro antidermatophytic activity of 23 crude extracts from nine plant species of semiarid vegetation (caatinga) found in Brazil. The extracts were tested at concentrations ranging from 1.95 to 1,000.0 mg/mL by broth microdilution assay against the reference strains T. rubrum ATCC 28189 and T. mentagrophytesATCC 11481, and 33 clinical isolates of dermatophytes. All plants showed a fungicidal effect against both fungal species, with MIC/MFC values of the active extracts ranging from 15.6 to 250.0 µg/mL. Selected extracts of Eugenia uniflora (AcE), Libidibia ferrea (AE), and Persea americana (AcE) also exhibited a fungicidal effect against all clinical isolates of T. rubrum and T. mentagrophytes complex. This is the first report of the antifungal activity of Schinus terebinthifolius, Piptadenia colubrina, Parapiptadenia rigida, Mimosa ophthalmocentra, and Persea americana against both dermatophyte species.

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J Biol Inorg Chem (2007) 12:777–787 DOI 10.1007/s00775-007-0229-7

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The literature on the thermosensitive properties of strains or species of Leishmania and of other miercorganisms is revised. Cutaneous or mucocutaneous strains that infect animais in the coldest areas of the skin or mucosa in general can not grow in tissue culture at 37°C or higher temperatures and their respiratory metabolism decreases at these temperatures. These facts suggest a thermosensitive event in some important metabolism phase of the organisme. The strains or species that are able to produce visceral leishmaniasis were probably originated from cutaneous strains after genetioally determined physiological adaptation, to warmer temperatures. These strains can not only visceralize in animais and man but will also grow in tissue culture at 36-37°C and the respiratory metabolism will be higher at such temperatures. There are reasons to believe that intermediate strains, i. e., with properties of both groupsí do exist. A thermosensitive physiological event is a more general phenomenon and examples of it can also be found in the fields of virology, bacteriology and mycology. It has practical applications since some of the diseases produced by these agents can be cured by treatments with heat or artificial fever. Experiments along these line were performed on hamsters with a Costa Rican strain of L. braziliensis as an experimental model. Even after intraperitoneal inoculation lesions appear in the nose, ears, paws and tail with a subcutaneous temperature bellow 33°C at 22-24°C. Healing of the lesión is accomplished by increasing room temperature. A good lesión is produced in the rump of the animal if the area is depilated (comercial cream depilatory) previously and the naked skin cooled artificially. Elevated temperature, or the growing back of the hair will tend to diminish or cure the lesion.

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

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Leber Congenital Amaurosis (LCA), the most severe inherited retinal dystrophy, is genetically heterogeneous, with 14 genes accounting for 70% of patients. Here, 91 LCA probands underwent LCA chip analysis and subsequent sequencing of 6 genes (CEP290, CRB1, RPE65, GUCY2D, AIPL1and CRX), revealing mutations in 69% of the cohort, with major involvement of CEP290 (30%). In addition, 11 patients with early-onset retinal dystrophy (EORD) and 13 patients with Senior-Loken syndrome (SLS), LCA-Joubert syndrome (LCA-JS) or cerebello-oculo-renal syndrome (CORS) were included. Exhaustive re-inspection of the overall phenotypes in our LCA cohort revealed novel insights mainly regarding the CEP290-related phenotype. The AHI1 gene was screened as a candidate modifier gene in three patients with the same CEP290 genotype but different neurological involvement. Interestingly, a heterozygous novel AHI1 mutation, p.Asn811Lys, was found in the most severely affected patient. Moreover, AHI1 screening in five other patients with CEP290-related disease and neurological involvement revealed a second novel missense variant, p.His758Pro, in one LCA patient with mild mental retardation and autism. These two AHI1 mutations might thus represent neurological modifiers of CEP290-related disease.

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A fim de obter metodologias que permitam estabelecer, com segurança, o diagnóstico "post-mortem " da infecção chagásica, adaptou-se o xenodiagnóstico artificial a necropsiados com diferentes tempos de óbito. O testefoi positivo em três (30%) de dez chagásicos autopsiados. O tempo decorrido entre o êxito letal e o início do repasto pelos triatomineos destes chagásicos foi de duas horas, duas horas e quinze minutos e sete horas, respectivamente. Discutem-se os fatores que podem explicara sobrevivência do Trypanosoma cruzi no hospedeiro morto bem como as aplicações práticas do achado.

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Proceedings IGLC-18, July 2010, Technion, Haifa, Israel

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

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Dissertação para obtenção do Grau de Doutor em Química Sustentável

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Dissertation presented to obtain the Ph.D degree in Biochemistry