976 resultados para south-central Montana
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Sexual dimorphism, reproduction and diet are described for Stenocercus caducus from semideciduous forest, in Mato Grosso do Sul state, Central Brazil. Lizards are collected in pitfall traps from December 2000, to December 2001. Sexual dimorphism in S. caducus is apparent, mainly in coloration; although females reach a larger SVL than males. A wide variety of arthropods are fed by S. caducus, with ants and termites numerically, and orthopterans and beetles volumetrically the most common prey items. Ontogenetic differences in diet were noted for S. caducus, with juveniles feeding on lesser prey types and smaller sized prey than adults. The reproduction was seasonal, concentrated in the rainy season, with deposition of more than one clutch per season.
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Information on endoparasites infecting Neotropical turtles is scarce. The present paper reports the occurrence of endoparasites in three adult individuals of Vanderhaege's Toad-Headed Turtle (Mesoclemmys vanderhaegei). The records include an undescribed nematode species in the genus Spiroxys, not previously reported for the family Chelidae, and the first South American record of a monogenetic trematode of the genus Neopolystoma.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Sexual maturity, temporal reproductive pattern, and recruitment of juveniles were examined for the penaeoid shrimp Artemesia longinaris sampled for five and a half years in a tropical locality off the coast of São Paulo (23 degrees S), Brazil. Monthly samples were taken from January 1998 to June 2003 at depths between 5 and 45 m. Ovarian maturity was used to examine breeding in adult females. Recruitment was defined as the percentage of juveniles of the total number of individuals in each month and season. A total of 10 288 females and 5 551 males were collected. Estimated sizes (carapace length) at the onset of sexual maturity were 11.0 mm and 13.4 mm for males and females, respectively. Over the five and a half years, females with ripe gonads were found in every season, with the highest percentages in summer (January-March). Juvenile shrimps occur-red year-round. These results suggest a continuous reproduction of A. longinaris with temperature acting as an environmental stimulus for the duration of the ovary development cycle. These data and the hypothesis of the intrusion of the South Atlantic Central Water mass, which lowered water temperature and raised plankton production, suggest that the end of spring and the beginning of summer were the principal reproductive months. The classical paradigm of continuous reproduction at lower latitudes, with increased seasonality of breeding period at higher latitudes seems to apply to this species.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The impact of shrimp fisheries in tropical regions has become comparable to the world's most intensively exploited temperate shed ecosystems. The increase in the fishing fleet in south-eastern Brazil and the decrease in landings of profitable shrimp species have contributed to the incorporation of additional species into those fisheries. The goal of the present study is to investigate the influence of environmental factors on the abundance patterns of shrimp communities on the south-eastern coast of Brazil, over a period of two years. Monthly collections were conducted in the Ubatuba and Caraguatatuba regions using a commercial shrimp fishing boat equipped with 'double-rig' nets. Each region was divided into 7 sampling stations up to 35 m deep. The relationship between the environmental factors and the abundance patterns in the shrimp communities was assessed using a canonical correlation analysis (CCorrA). The first set of variables used during the CCorrA included environmental characteristics and the second set of variables the abundance of the studied species. A total of 374,915 individuals were collected during the present study. Xiphopenaeus kroyeri showed the highest abundance (273,127), followed by Artemesia longinaris (73,422), and Pleoticus muelleri (15,262). In the first root, depth and temperature showed the highest factor loadings (0.9 and -0.7) and canonical weights (0.6 and -0.4). These environmental factors were strongly associated with the abundance of X. kroyeri (factor loading = - 0.9 and canonical weight = - 0.9). The second root demonstrated a positive relationship between abundance of P. muelleri and depth, and an inverse association with bottom temperature. The abundance patterns of X. kroyeri and P. muelleri were strongly affected by the water mass South Atlantic Central Water (cold waters =15 degrees C), which can lead to a temperature decrease in deeper areas (> 15 m). Thus, the opposite abundance trend for depth of these species might reflect bathymetric variation in temperature, a clear example of distinct behavioural differences of species of different origins, either tropical (X. kroyeri) or subantarctic (P. muelleri). The low overall association between environmental parameters and shrimp abundance patterns indicates that each studied species might have responded idiosyncratically to environmental variation, such that a general community-level response was not apparent. However, other confounding factors such as intraspecific migration patterns might have also played a role in generating the observed patterns.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)National Science Foundation (NSF)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The effects of temperature on lung and blood gases were measured in the South American rattlesnake (Crotalus durissus terrificus). Arterial blood and lung gas samples were obtained from chronically cannulated animals at 15, 25, and 35 degrees C. As expected for reptiles, arterial pH fell with increased temperature (0.018 U degrees C-1 between 15 and 25 degrees C and 0.011 U degrees C-1 between 25 and 35 degrees C) while lung gas PCO2 rose from 5.8 mmHg at 15 degrees C to 13.2 mmHg at 35 degrees C. Concurrently, lung gas PO2 declined from 132 mmHg at 15 degrees C to 120 mmHg at 35 degrees C, and arterial PO2 increased from 33 to 76 mmHg in that temperature range. Arterial haemoglobin O-2 saturation rose from 0.53 at 15 degrees C to 0.83 at 25 degrees C but became slightly reduced (0.77) with a further elevation of temperature to 35 degrees C. Arterial haemoglobin concentration increased from 1.96 to 2.53 mM between 15 and 35 degrees C, consistent with higher demands on oxygen delivery to tissues at elevated temperatures. Moreover, the substantial increase of haemoglobin O-2 saturation between 15 and 25 degrees C conforms to the idea that reduction of the central vascular right-to-left shunt (pulmonary bypass of systemic venous return) is associated with high metabolic demands. (C) 1998 Elsevier B.V. All rights reserved.
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Digestion is associated with gastric secretion that leads to an alkalinisation of the blood, termed the alkaline tide. Numerous studies on different reptiles and amphibians show that while plasma bicarbonate concentration ([HCO3-](pl)) increases substantially during digestion, arterial pH (pHa) remains virtually unchanged, due to a concurrent rise in arterial PCO2 (PaCO2) caused by a relative hypoventilation. This has led to the suggestion that postprandial amphibians and reptiles regulate pHa rather than PaCO2.Here we characterize blood gases in the South American rattlesnake (Crotalus durissus) during digestion and following systemic infusions of NaHCO3 and HCl in fasting animals to induce a metabolic alkalosis or acidosis in fasting animals. The magnitude of these acid-base disturbances were similar in magnitude to that mediated by digestion and exercise. Plasma [HCOT] increased from 18.4+/-1.5 to 23.7+/-1.0 mmol L-1 during digestion and was accompanied by a respiratory compensation where PaCO2 increased from 13.0+/-0.7 to 19.1+/-1.4 mm Hg at 24 h. As a result, pHa decreased slightly, but were significantly below fasting levels 36 h into digestion. Infusion of NaHCO3 (7 mmol kg(-1)) resulted in a 10 mmol L-1 increase in plasma [HCO3-] within 1 h and was accompanied by a rapid elevation of pHa (from 7.58+/-0.01 to 7.78+/-0.02). PaCO2, however, did not change following HCO3- infusion, which indicates a lack of respiratory compensation. Following infusion of HCl (4 mmol kg(-1)), plasma pHa decreased by 0.07 units and [HCO3-](pl) was reduced by 4.6 mmol L-1 within the first 3 h. PaCO2, however, was not affected and there was no evidence for respiratory compensation.Our data show that digesting rattlesnakes exhibit respiratory compensations to the alkaline tide, whereas artificially induced metabolic acid-base disturbances of same magnitude remain uncompensated. It seems difficult to envision that the central and peripheral chemoreceptors would experience different stimuli during these conditions. One explanation for the different ventilatory responses could be that digestion induces a more relaxed state with low responsiveness to ventilatory stimuli. (C) 2005 Elsevier B.V. All rights reserved.
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Foram listadas 263 aves próximo e dentro de uma mata semidecídua de 230 ha em meio a plantações de cana-de-açúcar, na região central do Estado de São Paulo, Brasil. Subtraindo-se 67 espécies de áreas abertas, 22 de riachos, 10 vagantes e 12 observadas mais tarde, cerca de 152 espécies de mata e de borda foram observadas entre 1982-86, semelhantemente às observadas em uma mata próxima a Campinas. Ambas as matas perderam espécies gradualmente. Algumas aves evitaram as margens duras dos canaviais, preferindo as margens macias arbustivas. Das espécies de área aberta, parece que 22 desapareceram até 1997, em razão das abundantes chuvas anteriores causadas por El Niño, ou pela raridade de habitats permanentemente abertos nos canaviais; 17 espécies novas eram principalmente noturnas que não haviam sido checadas anteriormente, ou visitantes ocasionais. A mata e as bordas perderam 37 espécies, ganhando 5 de regiões secas e 1 visitante de inverno. Vários migrantes do sul apareceram somente em anos chuvosos antes do recente efeito estufa; algumas aves residentes foram caçadas, e os beija-flores das copas talvez estivessem presentes ainda. As espécies de zonas secas, prones à movimentação ou metapopulacionais, movem os centros de distribuição, camuflando parcialmente a perda de diversidade da mata úmida.
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Abundant conchostracans occur in Coniacian-Santonian dark grey, argillaceous, lacustrine sediments of the Sao Carlos Formation, Bauru Group, Parana Basin, in the central part of São Paulo State, south-east Brazil. They are ascribed to a new genus and species, Bauruestheria sancarlensis, included in the family Jilinestheriidae. The new taxon is similar to some Late Cretaceous species from China and Mongolia. It probably evolved from a Late Jurassic-Early Cretaceous ancestral form (Migransia), which first lived in West Gondwana, and later dispersed to Europe and Asia, originating distinct parallel lineages with increasing ornamental complexity. The conchostracans probably lived in oxygenated marginal areas of a very calm, perennial lake with an anoxic bottom, and were transported in suspension to the depositional site by weak turbidity currents or storm-induced flows. Great concentrations of juvenile conchostracans in some thin layers can be related to mass mortality, episodes caused by convection and dispersion of anoxic water during storms. (c) 2005 Elsevier Ltd. All rights reserved.
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Characidium xanthopterum é descrita de tributários das bacias do alto Paraná e do alto Tocantins, no Planalto Central do Brasil, Estado de Goiás, Brasil. Entre as congêneres, a nova espécie é diagnosticada pela ausência de barras escuras nas porções laterais do corpo em exemplares adultos, e pela presença de todas as nadadeiras fortemente amareladas, sem marcas ou manchas. Exemplares menores de 32 mm CP apresentam barras escuras no corpo. Estas barras desaparecem com o crescimento entre 32 e 35 mm CP, e estão sempre ausentes em indivíduos maiores do que 35 mm CP.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)