68 research outputs found

    A História da Alimentação: balizas historiográficas

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    Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

    Problems of display postures in the Charadrii (Aves: Charadriiformes)

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    Studies of displays in the Charadrii (= waders or shorebirds) show that the same posture in different species, even quite closely related, may have a different function in a given context. As a corollary to this, two species even in the same genus may have quite different display postures to convey the same message. The problem is thus twofold: (a) to interpret the function of the display in the bird's world and (b) to trace the evolution of the display within a single well-defined suborder of birds such as the Charadrii. Threat displays are especially informative in such studies, but courtship, distraction and other displays are also useful. The value of display postures in the systematics of the waders is discussed

    Arid-zone adaptations of waders (Aves: Charadrii):

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    Assessing costs and benefits of pest management on forested landbases in eastern and western Canada

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    Spruce budworm Decision support system Timber product value Protection costs Insecticide use Benefit/cost ratio Net present value

    Induction of tetraploidy in transgenic tilapia (Oreochromis niloticus) using physical shocks

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    The induction of tetraploidy by means of cold, heat and multiple heat shock treatments was investigated on male fish from a growth-enhanced transgenic tilapia C118 line, crossed with wild type females. After the development a new multiple heat shock protocol (two heat treatments at 41oC in 60 and 80 min. after fertilization for 5 min. per each), chromosome and X-gal in situ staining assays demonstrated the successful production of yolk sac tetraploid transgenic tilapia in two out of 15 embryos examined in this trial via direct correlation between higher level of b-galactosidase expression and karyotyping in the samples verifying complete tetraploidy in this line. In the grown fish, there was evidence to suggest mosaicism or perhaps tetraploidy in at least two grown fish using the measurement of erythrocytes and karyotyping of the G1 offspring (p<0.05). There was, however, no evidence to indicate successful production of triploid G1 individuals following crossing of induced fish with wild type.Publishe

    Isolation and expression of tilapia (Oreochromis niloticus) serine 8-type GnRH coding and regulatory sequences

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    The complete Serine 8-type gonadotropin releasing hormone (GnRH) coding sequence with a substantial 5-prime regulatory sequence (5 kb) has been isolated and characterised in Nile Tilapia (Oreochromis niloticus) from a relevant genomic library. The primary structure of the protein precursor was identified for this gene. The promoter efficacy has been tested using 0.6 kb of the GnRH promoter driving a lacZ reporter gene in both cultured spleen cells and transiently expressing zebrafish. In the cell transfection experiments, the average level of b- galactosidase activity in transfected cells was more than 2.1 (P , 0:05) times higher than the control promoter-less vector in five independent cultures indicating that the 0.6GnRH/lacZ construct is able to express in spleen cells. In addition, the transient expression of the lacZ gene was detected in the brain of G0 zebrafish embryos (Danio rerio) 4 days after fertilisation following egg injection with the construct, which demonstrated the efficacy of the tilapia GnRH promoter. <br/
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