871 resultados para ecological zonation


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This paper considers ocean fisheries as complex adaptive systems and addresses the question of how human institutions might be best matched to their structure and function. Ocean ecosystems operate at multiple scales, but the management of fisheries tends to be aimed at a single species considered at a single broad scale. The paper argues that this mismatch of ecological and management scale makes it difficult to address the fine-scale aspects of ocean ecosystems, and leads to fishing rights and strategies that tend to erode the underlying structure of populations and the system itself. A successful transition to ecosystem-based management will require institutions better able to economize on the acquisition of feedback about the impact of human activities. This is likely to be achieved by multiscale institutions whose organization mirrors the spatial organization of the ecosystem and whose communications occur through a polycentric network. Better feedback will allow the exploration of fine-scale science and the employment of fine-scale fishing restraints, better adapted to the behavior of fish and habitat. The scale and scope of individual fishing rights also needs to be congruent with the spatial structure of the ecosystem. Place-based rights can be expected to create a longer private planning horizon as well as stronger incentives for the private and public acquisition of system relevant knowledge.

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The growth patterns of weight from birth through the first twelve months of life among rural Taiwanese infants were investigated with the following objectives: (i) compare each of the parameters of the Count model estimated for infants who were nutritionally at risk with those for a reference population from the United States; and (ii) within the Taiwanese infants, account for the variance in the growth patterns in the first and second six months of life on the basis of selected ecological factors.^ The significance between group differences were observed in the patterns of the weight growth in both linear growth and in the timing and the direction of velocity changes. A significant decline in growth velocity was observed among Taiwanese infants at about the fourth month of life. The decline is in keeping with a recent proposal made by J. C. Waterlow regarding the timing of change in growth velocity among nutritionally at risk populations in developing countries. The growth course of a nutritionally at risk infant during the first three months is apparently protected by the nurturance of the mother and innate biological properties of the infant.^ A highly significant portion of the growth variance in the second six months of life was accounted for by exogenous factors and biological factors related to the infant. Conversely, none of the growth variance in the first six months of life was accounted for by predictor variables. The most potent determinant of growth in the second six months of life was seasonality which represents a multiple environmental event.^ The model parameters estimated from the Count model represent different aspect of physical growth; yet the correlation coefficients between parameters b and c are high (r > .80). Clearly, the biological interpretation of the model parameters requires analysis of the whole function in the specific context of a given age period. ^

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In developing countries, infection and malnutrition, and their interaction effects, account for the majority of childhood deaths and chronic deficits in growth and development. To promote child health, the causal determinants of infection and malnutrition and cost-effective interventions must be identified. To this end, medical examinations of 988 children (age two weeks to 14 years) living at three altitudes (coastal < 300m; sierra (TURN) 3,000m; and altiplano > 4,000m) in Chile's northermost Department of Arica revealed that 393 (40%) of the youngsters harbored one or more infections. When sorted by region and ethnicity, indigenous children of the highlands had infection rates 50% higher than children of Spanish descent living near the coast.^ An ecological model was developed and used to examine the causal path of infection and measure the effect of single and combined environmental variables. Family variables significantly linked to child health included maternal health, age and education. Significant child determinants of infection included the child's nutrient intake and medical history. When compared to children well and free of disease, infected youngsters reported a higher incidence of recent illness and a lower intake of basic foodstuffs. Traditional measures of child health, e.g. birth condition, weaning history, maternal fertility, and family wealth, did not differentiate between well and infected children.^ When height, weight, arm circumference, and subcapular skinfold measurements were compared, infected children, regardless of age, had smaller arm circumferences, the statistical difference being the greatest for males, age nine to eleven. Height and weight, the traditional growth indices, did not differentiate between well and infected groups.^ Infection is not determined by a single environmental factor or even a series of variables. Child health is ecological in nature and cannot be improved independent of changes in the environment that surrounds the child. To focus on selected child health needs, such as feeding programs or immunization campaigns, without simultaneously attending to the environment from which the needs arose is an inappropriate use of time, personnel, and money. ^

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The Southern Marion Plateau (SMP) represents a vertical stacking of Miocene carbonate platform deposits. Two sites (1196 and 1199) were drilled on top of this plateau, penetrating a 663-m carbonate succession of bioclastic and reefal sedimentary bodies. The study focuses on the least dolomitized 410-m-thick upper part of the succession, which is middle to late Miocene in age. Sedimentological and paleontological studies were conducted at both sites in order to propose a paleoenvironmental model and its evolution through the Miocene age. Six main microfacies of possible environmental significance were defined using statistical multivariate analyses, based on the recognition and point counting of 24 biogenic components. Depositional environment reconstructions are proposed as well as the biosedimentary and the environmental evolution regarding seismic architectures, stratigraphy, biosedimentology, and microfacies analysis. The SMP platform mainly results from a vertical stacking of lens-shaped bodies in homoclinal to distally steepened ramp settings.