978 resultados para Adaptação marginal (Odontologia)


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Three nematodes, two acanthocephalans and three cestodes were collected by dissecting 15 species of fish. Of these parasites only Hedruris sp. a larval nematode is responsible directly for the death of fish, since it is found in predatory species a reduction of these might prove of considerable consequence to fish, production. Bothriocephalus gowleonensis, a cestode probably introduced from China with Chinese carp, was recorded in an indigenous carp Puntius sarana. This parasite causes heavy mortality in grass carp in China and is a potential danger to local species. A single crustacean parasite was recorded. It is likely that they are widespread. No protozoa were recorded but there can be little doubt that they occur in local freshwater species and may be of considerable importance in fisheries. Several predators (insects, fish and other vertebrates) were recorded and are doubtless of considerable importance. However, the role of parasites and of predators (especially fishes) in relation to the productivity of fisheries can hardly be assessed at present and needs further study. A study of the fauna found at the shallow edges of 21 irrigation reservoirs showed an abundance of fauna in the low-country reservoirs whilst the up-country reservoirs had a poor fauna. The fauna showed insects, crustacea and mollusca in this order of abundance. The presence of insect and molluscs feeding fish in our fauna shows that these rich sources of food are being utilised.

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The diet and feeding ecology of a wild subpopulation of black-and-white snub-nosed monkeys (Rhinopithecus bieti) were studied at Xiaochangdu in Honglaxueshan Nature Reserve, Tibet. This region is climatologically harsher than any other inhabited by non-human primates. Black-and-white snub-nosed monkeys fed on 48 parts of 25 plant species, at least three species of lichens and seven species of invertebrates. The number of food items exploited varied markedly among seasons, with dietary diversity being greatest in spring and summer. In winter, black-and-white snub-nosed monkeys had to subsist on fallback foods such as dried grass and bark. Ubiquitous lichens formed a major dietary constituent throughout the year, contributing about 75% of feeding records. Even though lichens act as a staple, our findings signify that the monkeys at Xiaochangdu prefer feeding on foliage, which is higher in protein content than the former. We provide evidence that black-and-white snub-nosed monkeys are able to cope with an array of food items other than lichens and hence can be regarded as feeding generalists. We discuss the results with reference to previous studies on other subpopulations living in habitats that are floristically more diverse and offer more plant food items than the marginal habitat at Xiaochangdu.

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Marginal utility theory prescribes the relationship between the objective property of the magnitude of rewards and their subjective value. Despite its pervasive influence, however, there is remarkably little direct empirical evidence for such a theory of value, let alone of its neurobiological basis. We show that human preferences in an intertemporal choice task are best described by a model that integrates marginally diminishing utility with temporal discounting. Using functional magnetic resonance imaging, we show that activity in the dorsal striatum encodes both the marginal utility of rewards, over and above that which can be described by their magnitude alone, and the discounting associated with increasing time. In addition, our data show that dorsal striatum may be involved in integrating subjective valuation systems inherent to time and magnitude, thereby providing an overall metric of value used to guide choice behavior. Furthermore, during choice, we show that anterior cingulate activity correlates with the degree of difficulty associated with dissonance between value and time. Our data support an integrative architecture for decision making, revealing the neural representation of distinct subcomponents of value that may contribute to impulsivity and decisiveness.

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Diatom data of 192 surface sediment samples from the marginal seas in the western Pacific together with modern summer and winter sea surface temperature and salinity data were analyzed. The results of canonical correspondence analysis show that summer sea-surface salinity (SSS) is highly positively correlated with winter SSS and so is summer sea-surface temperature (SST) with winter SST. The correlations between SSSs and SSTs are less positively correlated, which may be due to interactions of regional current pattern and monsoon climate. The correlations between diatom species, sample sites and environmental variables concur with known diatom ecology and regional oceanographic characters. The results of forward selection of the environmental variables and associated Monte Carlo permutation tests of the statistical significance of each variable suggest that summer SSS and winter SST are the main environmental factors affecting the diatom distribution in the area and therefore preserved diatom data from down core could be used for reconstructions of summer SSS and winter SST in the region.

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This study investigates the distribution of black carbon (BC) and its correlation with total polycyclic aromatic hydrocarbons (I PAH) pound in the surface sediments of China's marginal seas. BC content ranges from < 0.10 to 2.45 mg/g dw (grams dry weight) in the sediments studied, and varied among the different coastal regions. The Bohai Bay sediments had the highest BC contents (average 2.18 mg/g dw), which comprises a significant fraction (27%-41%) of the total organic carbon (TOC) preserved in the sediments. In comparison, BC in the surface sediments of the North Yellow Sea, Jiaozhou Bay, East China Sea and the South China Sea is less abundant and accounted for an average of 6%, 8%, 14% and 5%, respectively, of the sedimentary organic carbon pool. The concentration of I PAH pound in the surface sediments ranges from 41 to 3 667 ng/g dw and showed large spatial variations among the sampling sites of different costal regions. The Bohai Bay has the highest I PAH pound values, ranging from 79 to 3 667 ng/g dw. This reflects the high anthropogenically contaminated nature of the sediments in the bay. BC is positively correlated to TOC but a strong correlation is not found between BC and I PAH pound in the surface sediments studied, suggesting that BC and PAHs preserved in the sediments are derived from different sources and controlled by different biogeochemical processes. Our study suggests that the abundance of BC preserved in the sediments could represent a significant sink pool of carbon cycling in China's marginal seas.

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With the rapid development of satellite observations, we can use the altimetry geoid to study submarine tectonics and geodynamics. On the basis of the 4' x 4' geoid undulation calculated from altimeter data of Geosat, ERS-1/2 and Topex/Poseidon on the West Pacific, located between 0degreesN similar to 45degreesN, 100degreesC similar to 150degreesE, Bouguer, Glenni and isostatic geoid undulation are obtained from correction of gravitational potential of the global topography and isostacy. Moho discontinuity depth is inversed by the Glenni geoid undulation, and the stress field from small-scale mantle convection is reasonably calculated from the isostatic geoid undulation. The results show that within the Philippine Sea and the South China Sea, short-wavelength lineations of the geoid undulation are parallel or cross to magnetic lineations and rifting ridges. The Moho depth of marginal sea basins becomes shallow southward, and its values are similar to that of the Philippine Sea. These facts show that strength of tectonic activities are almost the same on the both sides of the Ryukyu-Taiwan-Philippine are. Various kinds of tectonic features with different driving mechanisms of small-middle and large-scale of mantle convection, however, display a special pattern of tectonics and geodynamics of the continental marginal seas distinguished from oceans and continents.

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Terrigenous components were separated from the bulk sediment of Core A7 from the Okinawa Trough and Core A37 from the Ryukru Trench and grain-size distributions of these sub-samples were analyzed. Based upon an analysis of the grain-size data of the two sedimentary sequences, grain-size populations are identified to be sensitive to sedimentary environmental changes. The modal values and size ranges of the two main grain-size populations in Core A7 are evidently different from those of Core A37, indicating the spatial variability of sediment sources and transport processes between the two places. The downcore variations in the content of the environmentally sensitive grain-size populations reveal that during the accumulation of sedimentary material the environment remained relatively stable at the site where Core A7 was collected, except for the apparent events for the formation of two turbidite layers and a volcanic ash layer. However, the sedimentary sequence of Core A37 shows six sedimentary cycles, indicating a highly variable sedimentary environment at this location.

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The characteristics and distribution patterns of detrital minerals (0.063 similar to 0.125 mm) in marine sediments provide a significant indicator for the identification of the origin of sediment. The detrital mineral composition of 219 surface sediment samples was analysed to identify the distribution of sediments within the western Philippine Sea. The area can be divided into three mineral provinces: ( 1) province east of the Philippine Trench, the detrital minerals in this province are mainly composed of calcareous or siliceous organisms, with the addition of volcanogenic minerals from an adjacent island arc; (II) middle mineral province, clastic minerals including feldspar, quartz and colorless volcanic glass, sourced from seamounts with intermediate-acid volcanic rock, or erupting intermediate-acid volcano; (III) province west of the Palau-Kyushii Ridge, the matter provenance within this province is complex; the small quantity of feldspar and quartz may be sourced from seamounts or erupting volcano with intermediate - acid composition, with a component of volcanic scoria sourced from a volcano erupting on the Palau-Kyushu Ridge. it is suggested that, ( I) Biogenic debris of the study area is closely related to water depth, with the amount of biogenic debris controlled by carbonate lysocline. (2) Volcaniclastic matter derived from the adjacent island are can be entrained by oceanic currents and transported towards the abyssal basin over a short distance. The weathering products of volcanic rocks of the submarine plateau ( e. g. I Benham Plateau) and adjacent ridges provide an important source of detrital sedimentation, and the influence scope of them is constrained by the intensity of submarine weathering. (3) Terrigenous sediments from the continent of Asia and the adjacent Philippine island arc have little influence on the sedimentation of this study area, and the felsic mineral component is probably sourced from volcanic seamounts of intermediate-acid composition.

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Peso da parte aérea, Nossa Senhora das Dores; Peso de raízes, Nossa Senhora das Dores; Teor de matéria seca de raíz, Nossa Senhora das Dores; Teor de amido, Nossa Senhora das Dores; Peso da parte aérea, Lagarto; Peso de raízes, Lagarto; Teor de matéria seca de raíz, Lagarto; Teor de amido, lagarto; Altura da planta, Lagarto; Altura da 1º ramificação, Lagarto; peso da parte aérea, Umbaúba; Peso de raíz, Umbaúba; Teor de matéria seca de raíz, Umbaúba; Teor de amido, Umbaúba; Altura da planta, Umbaúba; Altura da 1º ramificação, Umbaúba; comprimento de raíz, Umbaúba; Ensaio de variedades e híbridos de mandioca; Avaliação de cultivares de mandioca no período 2004/2006; Peso da parte aérea, Nossa Senhora das Dores; peso de raízes, Nossa Senhora das Dores; Índice de colheita, Nossa Senhora das Dores; Teor de matéria seca de raíz, Nossa Senhora das Dores; Teor de amido, Nossa Senhora das Dores

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2006