988 resultados para Gershenzon, M. O. (Mikhail Osipovich), 1869-1925


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The reproductive capacity of the swimming crab Callinectes danae Smith, 1869 was assessed based on the reproductive investment (RI) of ovigerous females and the gonadosomatic index (GI) of non-ovigerous adult females. Crabs were collected in June 2009 with a shrimp fishing boat at Ubatuba (23° 26′S 45° 02′W) São Paulo, Brazil. Overall, 191 adult females were analyzed, of which 108 were ovigerous and 83 non-ovigerous. The size of ovigerous females ranged from 54.5 to 79.8 mm carapace width (CW) and non-ovigerous females ranged from 56.0 to 80.9 mm CW. RI values did not differ among the size classes (ANOVA, p > 0.05), with an overall mean of 15.8%. The same occurred with the Gonadossomatic index for non-ovigerous females, for which the mean value was 11.7%. The regression between the dry weight of the egg mass and the dry weight of the crab (Student’s t, p = 0.25; ttab = 1.66; tcal = 0.66) indicated an isometric relationship for the variables analyzed. The simultaneous occurrence of gonadal maturation and embryonic development in ovigerous females suggests that these crabs may spawn at least twice in the same breeding season and reveals the need for evaluation of the allocation of energy in subsequent spawns.

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Lipids have important biological functions, suchas membrane constituents, hormone precursors, and are efficient energy reserves, due to thers high caloric content. In fish, but not in mammals, lipid storage patterns are quite diverse. The aim of this study was to determine lipid distribution in somatic and reproductive tissues of matrinxã, Brycon cephalus, both male and female, highlighting somatic indices related to lipid dynamics. From Oct 98 to Jan 99, a total of 174 fish (8-12 each month) were sampled. After fish anesthesia, heparinized blood was collected for plasma triacylglycerol determination. Fish were individually weighed and measured, and liver, gonads and visceral fat were collected and weighed for HSI (hepatosomatic index), GSI (gonad somatic index) and MFI (mesenteric fat index) calculation. The highest values of total lipids were found in red muscle (about 18%), liver and gonads (about 16.5%). The white muscle had a lower concentration (2.5%). Analyses of variance of HSI and MFI showed fluctuations along the experimental period with lowest concentrations in the periods of highest temperatures. Matrinxã store lipids in several body tissues, including mesenteric fat, liver, muscles and gonads.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The original idea of using a trench for the storing of ensilage seems to have been the outgrowth of the practice long used in several European countries of storing clover and beet tops in pits. Shortly after the World War, western Canada followed by Montana and North Dakota began to use the trench silo. In Nebraska the true trench silo made its appearance about 1925 or 1926. The trench silo as described in this circular, unless lined with some permanent material such as brick, concrete or stone, must be considered a temporary structure which will serve for a few years only and then must be discarded or rebuilt. In an emergency it will save a crop even though the farmer has little capital to expend other than his own labor.

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In this short but suggestive study, sociologist Rod Bantjes examines how contending visions of modernity shaped the social and physical landscapes of the Canadian prairies. "[B]oth statesmen and prairie farmers were infused with the modernist spirit of innovation, the will creatively (and destructively) to transform their worlds," Bantjes argues. His provocative view of farmers as agents of modernity reflects recent scholarship that seeks to explore "multiple modernities," or the notion that ideas and practices of modernism must be regarded not as monolithic but rather as contested and multivocal, and must be examined in their historical and geographical contexts.

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The influence of the 1992-1993 El Nino events on the reproductive behavior of the Scomber japonicus peruanus (Chub mackerel) was studied from samples collected monthly, along the Peruvian coast (3 degrees 23`S-14 degrees 00`S), from January 1990 to December 1993. The monthly variation of the gonadosomatic index and the frequency of the periods of gonad maturation evidenced that the spawning of the species occurred all year long, being more intense in summer. The values of the gonadosomatic index were higher during the occurrence of the 1992-1993 El Nino, while the body weight and gonad weight decreased. Regarding the condition factor, its values decreased in females over 35 cm in fork length.

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The growth parameters and the mortality rates of the Scomber japonicus peruanus (Chub mackerel) were studied based on monthly data of frequency of fork length classes obtained from commercial landings off the Peruvian coast from 1996 to 1998. The asymptotic body length and growth rate values obtained by the ELEFAN I (Electronic Length Frequency Analysis) ranged from 40.20 cm to 42.20 cm and from 0.38 to 0.39, respectively. The oscillation amplitude was 0.60; the Winter point values varied from 0.50 to 0.60 and the performance index from 2.79 to 2.84. The total mortality rate of the Chub mackerel obtained by the linearized catch curve oscillated between 1.68 and 3.35. The rate of fishing mortality varied from 1.16 to 2.78 and the exploitation rate from 0.68 to 0.84. The annual rate of natural mortality estimated by the Pauly`s method ranged from 0.52 to 0.53. The results obtained allow us to conclude that the longevity of the Chub mackerel was slightly over seven years.

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Dinoflagellates of the genus Ceratium are chiefly marine but there are rare occurrences in freshwater. In this study we analyze the invasion and progressive establishment of Ceratium furcoides, an exotic species, in the Furnas Reservoir. Samples were taken at 36 points in the reservoir, during the months of March, June, September and December, 2007. Measurements of some physical and chemical variables were simultaneously performed at each site. The occurrence of C. furcoides was registered at 20 sites, with densities varying between 0.57 and 28,564,913.0 ind.m(-3). Blooms of this species were recorded in points which were classified as mesotrophic, coinciding with the places receiving high amounts of untreated domestic sewage. C. furcoides density was correlated with temperature, nutrients (nitrate and nitrite) and water electric conductivity. The highest density was recorded in June when temperature was low. The presence of Ceratium furcoides in the reservoir apparently has not yet affected the reservoir water quality or other plankton communities. However, if it becomes fully established it could perhaps become a problem in the reservoir or even to spread out to other reservoirs in Rio Grande basin.

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Dinoflagellates of the genus Ceratium are chiefly marine but there are rare occurrences in freshwater. In this study we analyze the invasion and progressive establishment of Ceratium furcoides, an exotic species, in the Furnas Reservoir. Samples were taken at 36 points in the reservoir, during the months of March, June, September and December, 2007. Measurements of some physical and chemical variables were simultaneously performed at each site. The occurrence of C. furcoides was registered at 20 sites, with densities varying between 0.57 and 28,564,913.0 ind.m-3. Blooms of this species were recorded in points which were classified as mesotrophic, coinciding with the places receiving high amounts of untreated domestic sewage. C. furcoides density was correlated with temperature, nutrients (nitrate and nitrite) and water electric conductivity. The highest density was recorded in June when temperature was low. The presence of Ceratium furcoides in the reservoir apparently has not yet affected the reservoir water quality or other plankton communities. However, if it becomes fully established it could perhaps become a problem in the reservoir or even to spread out to other reservoirs in Rio Grande basin.