Pesca experimental de corrico na zona sul da costa de Mocambique

Based on the proven existence of large pelagic fish resources in the southern coast of Mozambique, an experimental fishing trolling program has been designed to study the possibility of resources exploitation through the introduction of trolling technique on artisanal vessels (Project FAO/TCP/MOZ/5653). Although operational problems occurred, the program carried out during the year 1957, provided a collection of data and knowledge. It allowed the preparation of present paper, which could serve as an indicator for a possible implementation of this fishing method in the Mozambican artisanal sector. Sharing this study, the author expects to give a further contribution to the development of a greater pelagic fishery in the waters of Mozambique.

CORRELATION OF ZONA-BINDING WITH OOCYTE MATURATION AND SPERM MOTILITY IN RHESUS-MONKEYS BY HEMIZONA ASSAY

The hemizona assay (HZA) in Rhesus monkeys was employed to study the correlation of zona-binding ability with sperm motility or with naturally developing oocytes at various maturational stages. Oocytes from unstimulated ovaries were retrieved within 2 hr from monkeys sacrificed for vaccine production (in reproductive season, but with their menstrual cycles not determined). Oocytes were divided into four groups based on their morphological maturation: 1) Oocytes surrounded by more than one cumulus layer (MC); 2) Oocytes retaining intact germinal vesicle nuclei (GV); 3) Oocytes with germinal vesicle breakdown showing distinct perivitelline space (PVS); and 4) Oocytes extruding the first polar body (PB1). The mean numbers of sperm bound to hemizona for PBI, PVS, GV, and MC groups were 132.9 +/- 12.0, 71.5 +/- 10.1, 36.1 +/- 4.0, and 20.1 +/- 2.9 (Mean +/- SE), respectively. The four groups showed significant differences from each other in sperm/egg binding ability (P < 0.01). The number of bound sperm significantly increased with oocyte maturation. The present study also showed that zona-binding ability was also affected by sperm motility. For sperm with 67.7% motility and sperm with 31.2% motility, the average numbers of bound sperm were 43.5 +/- 2.2 and 25.3 +/- 2.9 (Mean +/- SE), respectively. There was significantly higher binding ability for sperm with higher motility (P < 0.01). The results suggest that: 1)The rhesus monkey model can serve as a very sensitive model for studying sperm/egg interaction by HZA; 2) Sperm motility positively correlated with sperm/egg binding; and 3) Sperm/egg binding ability increases with oocyte maturation. The binding ability is highest when oocytes matured to the PB1 stage, which is also the best opportunity for fertilization. This is strong evidence for the ''zona maturation'' hypothesis. (C) 1994 Wiley-Liss, Inc.

Development of zona-free hamster ova to blastocysts in vitro

The zona pellucida (ZP) enclosing the mammalian ovum is important for its protection and for initial stages of fertilization, but the role of the ZP during embryo development is less clear. This study was designed to investigate if the hamster ZP is needed for embryo development from 1-cell to blastocyst in vitro, and to compare methods for removing the ZP. A total of 395 hamster pronucleate ova were collected 10 h post activation from superovulated, mated female hamsters. The ZP was removed from some ova using either 0.05% pronase, 0.05% trypsin or acid Tyrode's solution. To prevent ZP-free ova from sticking together, they were cultured singly in 30-50 muL drops of HECM-6 culture medium together with ZP-intact ova as controls. There was no significant difference among treatment groups in embryo development to blastocyst: 36/87 (42%) in the ZP intact group; 35/75 (47%) in the pronase-treated ZP-free group; 37/74 (50%) in the trypsin-treated ZP-free group; and 37/71 (52%) in the acid-treated ZP-free group. These results indicate that 1) the ZP is unnecessary for hamster embryo development in vitro from the pronucleate ovum stage to blastocyst; 2) none of the three ZP-removal methods was detrimental to embryo development; 3) embryos do not need to be cultured in groups during in vitro development from 1-cell to blastocyst. (C) 2000 by Elsevier Science Inc.

Estimativa do acúmulo de biomassa e carbono por sistema silvipastoril implantado em área montanhosa da Zona da Mata Mineira.

2007

Ocorrência de espécies arbustivas e arbóreas em pastagens da micro-região de Juiz de Fora, Zona da Mata de Minas Gerais.

2008

Extrativismo animal em zona de fronteira agrícola na Amazônia.

Os programas de colonização na Amazônia tem chamado atenção de cientistas, autoridades e ambientalistas para o impacto ambiental causado por desmatamentos e queimadas na faixa de fronteira agrícola. O extrativismo vegetal tem sido merecedor de grande atenção por parte destes grupos, mas pouca ênfase tem sido dada ao extrativismo animal. A forma como este é praticado pelas populações ribeirinhas, indígenas e de seringueiros já foi objeto de alguns estudos; porém, os conhecimentos disponíveis sobre extrativismo animal em projeto de colonização em área de fronteira agrícola são inexistentes. Se, o extrativismo animal é pouco conhecido é ainda menos estudado e monitorado quanto ao impacto que exerce sobre a composição e estrutura dos povoamentos e populações faunísticas. Este tópico merece uma avaliação criteriosa, pois a caça é uma atividade tradicional na vida das populações rurais brasileiras, destinando-se principalmente à subsistência das mesmas. Em áreas de fronteira agrícola, onde aproximadamente 70% dos colonos são originários de outros ecossistemas, pouco se sabe sobre o extrativismo animal por eles praticados. Este estudo investigou a utilização dos recursos cinegéticos amazônicos por estes colonos e o impacto que estas atividades causam na fauna amazônica. O município escolhido foi Machadinho d´Oeste, em Rondônia, implantado por um projeto de colonização elaborado pelo INCRA e financiado pelo BANCO MUNDIAL, e que, até 1980, possuía sua área toda florestada e intacta. Hoje, cerca de 20 anos após, tem uma interface agrícola e fauna silvestre , com inter-relações específicas, pouco conhecidas e avaliadas. O conhecimento dessas relações possibilita a adoção de medidas corretas para o monitoramento destas áreas que têm estendido suas fronteiras nos últimos anos.

Recomendação de cultivares de milho para a zona agreste do nordeste brasileiro: safra 2007.

2008