352 research outputs found

    Material paleontológico no Claustro da Academia das Ciências de Lisboa

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    Fósseis encontrados nas escavações permitiram identificar os táxones indicados no Quadro 1, que datam do Cretácico (Cenomaniano superior) e outros do Miocénico inferior (Aquitaniano). Todos os fósseis foram encontrados em posição secundária, nunca in situ. A origem primária dos fósseis do Miocénico inferior pode situar-se nas proximidades imediatas ou em áreas bastante próximas. A ocorrência pode resultar de simples remeximento local de sedimentos. Quanto aos rudistas do Cenomaniano superior, é provável que a sua presença indique transporte acidental, de mistura com restos humanos, a partir de afloramentos de enchimentos cársicos, entulhos ou solos com fósseis desagregados; o que corrobora outras indicações indicativas de transporte de despojos humanos oriundos de áreas algo afastadas. A sua origem situar-se-ia, o mais perto, na faixa de calcários que se estende de Alcântara às imediações de Santos-o-Velho, de onde proviria também material humano

    Fauna malacológica moderna no Claustro da Academia das Ciências de Lisboa

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    A malacofauna marinha autóctone colhida no Claustro do Convento de Jesus (Academia das Ciências de Lisboa), inclui 21 espécies de bivalves e 15 de gastrópodes. Muito variada, é compatível com as condições ecológicas no Mar da Palha até a década de 60 do século xx. Desde então, a poluição levou ao desaparecimento de muitas espécies. Predominam moluscos consumidos: mexilhão (Mytilus), ostras( Ostrea, Crassostrea), sobretudo o berbigão (Cerastoderma), amêijoas (Spisula e Tapes) e Burriés (Littorina. etc.), outrora abundantes nos fundos litorais das praias arenosas circundantes de Lisboa. A escassez de lapa (Patella), conquilha (Donax) e lam- bujinha (Scrobicularia) poderá significar maior distância aos locais de recolh

    Langhian rays (Chondrichthyes, Batomorphii) from Brielas, Lower Tagus Basin, Portugal

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    The Langhian Vc unit of Brielas section (Caparica road, Almada), in the marine Miocene of the Lower Tagus Basin (West Portugal), is rich in batoid species. In this study, batoids are represented by 149 isolated fossil teeth and a single fossil dental plate collected from a bulk sample of washed and sorted sediment. A total of 12 species belonging to the orders Rhinopristiformes, Rajiformes, Torpediniformes and Myliobatiformes were identified. All genera and some species are known to have extant representatives. Aetobatus cappettai Antunes and Balbino, 2006, is described now from Langhian material which suggests it is older than previously supposed. The biogeographic ranges, environmental constraints and behaviour of the species described in this study point out to an infralittoral environment characterized by the dominance of warm water conditions, where episodic upwelling contributed to the occurrence of different types of batoids coexisting in the same habitat

    Qualidade de carcaça de novilhos terminados com dietas contendo levedura, monensina e associação de ambos aditivos

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    To evaluate the effects of the supplementation of feed additives on carcass quality in beef cattle, 72 Nellore steers (339.5kg, 20-month old) were feedlot finished and fed for 91 days one of the following diets: 1) control with no additives; or added of 2) live yeast culture; 3) monensin; or 4) the association of both additives. After slaughter, renal, pelvic, and inguinal fat and hot carcass weights were recorded and carcass was split into muscle, bone, and trimmable fat. Carcass Longissimus muscle area and subcutaneous fat thickness at the 12th rib were measured and steaks of Longisimus muscle were taken to determine meat color, shear force, drip, and cooking losses. Yeast increased carcass dressing percentage but there were no effects on hot carcass weight, Longissimus area, subcutaneous fat thickness, percentage and weight of retail cut yield and trimmings. Feed additives had no effect on carcass pH, meat color, fat content, shear force, and drip losses. Supplementation of yeast, monensin or the association of both additives had no important effects on carcass traits and on meat quality of feedlot finished steers.Avaliaram-se os efeitos da suplementação de aditivos alimentares sobre a qualidade de carcaça em bovinos de corte. Usaram-se 72 novilhos Nelore com média de peso de 339,5kg e 20 meses de idade, terminados em confinamento e alimentados por 91 dias com uma das quatro dietas: 1) dieta controle sem aditivos, ou com a adição de 2) leveduras vivas, 3) monensina ou 4) associação entre ambos aditivos. Após o abate, os pesos da gordura renal, pélvica e inguinal e da carcaça foram medidos e a carcaça dividida em músculos, ossos e aparas. Foram mensurados a área de olho de lombo e a espessura de gordura subcutânea sobre o músculo Longissimus na região da 12ª costela e foram obtidos bifes para a determinação da cor, força de cisalhamento e perdas por cocção e cozimento da carne. A levedura aumentou o rendimento de carcaça, mas não houve efeito dos tratamentos sobre o peso de carcaça, porção comestível e aparas. Os aditivos não influenciaram o pH da carcaça, a cor, a gordura intramuscular, a força de cisalhamento e as perdas por exsudação da carne. A suplementação, com levedura e com monensina em associação ou separadamente, não teve efeito importante sobre a qualidade da carcaça em novilhos terminados em confinamento.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Supression of magnetic subbands in semiconductor superlattices driven by a laser field

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    The effect of strong laser radiation on magnetic subbands in semiconductor superlattices is investigated. Due to the presence of a magnetic field perpendicular to the growth direction, non-linear effects such as band supression and electron localization become relevant at relatively lower intensities and for any polarization perpendicular to the magnetic field. Electron quasienergies and density of states are calculated in the Kramers-Henneberger approximation, whose validity is discussed. The conditions under which collapse of magnetic subbands and quenching of N-photon emission or absorption processes occur are discussed. We conclude that at laser frequencies close to cyclotronic frequency and intensities typical of c.w. lasers, magnetic subbands become flat, magnetotunneling is inhibited and multiphotonic processes dominate optical absorption.Comment: 4 pages RevTex, 2 figure

    a pilot study in mice

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    Pneumocystis pneumonia (PcP) is a major cause of mortality and morbidity in immunocompromised patients. There are limited alternative therapeutic choices to trimethoprim-sulfamethoxazole (TMP-SMX) which is the standard first line therapy/prophylaxis for PcP. The efficacy of low doses of caspofungin and caspofungin in association with TMP-SMX standard-prophylactic dose was evaluated in an experimental model of Pneumocystis. Susceptibility of Pneumocystis spp. to low doses of caspofungin and caspofungin/TMP-SMX was evaluated in Balb/c immunosuppressed mice, infected intranasally with P. murina. Caspofungin was administered once daily at 0.1 mg/kg, 0.05 mg/kg, and 0.001 mg/kg and TMP-SMX was administered by oral gavage (12.25 mg/62.5 mg/day), for 21 days. Efficacy was calculated based on the reduction in organism burden determined through quantitative fluorescent-based real-time PCR (qPCR). Serum β-1,3-D-glucan was measured as an additional marker of infection. The present data showed that caspofungin demonstrated anti-Pneumomocystis effect. However, the doses administrated were too low to achieve Pneumocystis eradication, which suggests that echinocandin treatment should not be administrated as mono-therapy. After 21 days of treatment, P. murina was not detected in the lungs of mice with either TMP-SMX or caspofungin/TMP-SMX. The results showed that, even at the lowest concentrations tested, the efficacy of caspofungin in association with TMP-SMX was higher than the efficacy of either drug used alone. The administration of caspofungin/TMP-SMX was at least 1.4 times more effective against P. murina infection than TMP-SMX used alone. The most promising result was achieved with the combination of caspofungin 0.05 mg/kg/day with TMP-SMX 12.5 mg–62.5 mg/day, which reduced the parasite burden to undetectable levels immediately at the 14th day of treatment, showing a highly marked anti-Pneumomocystis effect. These data suggest that the administration of low doses of caspofungin in combination with low doses of TMP-SMX may provide an improved treatment protocol for Pneumocystis infection clearance.publishersversionpublishe

    Debate sobre o artigo de Narvai et al.

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    English title: Debate on the paper by Narvai et al.Margareth Crisóstomo Portela & Mauricio Teixeira Leite de Vasconcello
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