124 resultados para Ergodic Rates


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Indices of socio-economic deprivation are often used as a proxy for differences in the health behaviours of populations within small areas, but these indices are a measure of the economic environment rather than the health environment. Sets of synthetic estimates of the ward-level prevalence of low fruit and vegetable consumption, obesity, raised blood pressure, raised cholesterol and smoking were combined to develop an index of unhealthy lifestyle. Multi-level regression models showed that this index described about 50% of the large-scale geographic variation in CHD mortality rates in England, and substantially adds to the ability of an index of deprivation to explain geographic variations in CHD mortality rates.

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Long-distance bird migration consists of several flight episodes interrupted by a series of resting and refuelling periods on stopover sites. We assessed the role of food availability as the determinant of staging decisions focusing on the following three aspects of food availability: intake rates, stochasticity in intake rates and onset of spring. Using stochastic dynamic modelling, we investigated their impact on staging times and expected fitness. Subsequently, we compared relations in the use of the stopover sites as predicted by the model with empirical data of the Svalbard-breeding population of Pink-footed Goose Anser brachyrhynchus collected in the period 1990–2002. Our results indicate that, for the case of Pink-footed Geese, spring phenology determines a major part of the migration schedule. In contrast to our expectations, intake rates were generally only of minor importance; however, when approaching the breeding grounds their significance increased. Expected fitness at arrival on the breeding grounds showed that the geese can compensate for changes in a broad range of food availability and also cope with varying degrees of stochasticity. However, declining intake rates at the last stopover site or very late onsets of spring clearly decreased fitness. As predicted by the model, the use of stopover sites was interdependent – from empirical data we derived negative relationships between the staging durations of subsequent sites. These results lend credit to an integrated spatially explicit approach focussing on multiple stopover site characteristics when attempting to improve our understanding of bird migration.

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Although there has been significant research on US financial intermediaries' stock returns and sensitivity to interest yields, there has only been limited research on Australian bank stock returns and key macro variables, such as interest rates and exchange rates. The aim of this article is to examine this relationship for four major Australian banks, namely the Australia New Zealand bank (ANZ), the Commonwealth Bank of Australia (CBA), the National Australia Bank (NAB) and the Westpac Banking Corporation (WBC). We use the EGARCH model and examine the relationship using monthly data covering the period 1992 to 2007. The results suggest that for all four banks: (1) there is a similar and statistically significant negative relationship between interest rates and stock returns; and (2) there is evidence of an increase in returns during the period of appreciation of the Australian dollar.

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The influence of shear intensity (G) induced by mechanical mixing on activated sludge characteristics as well as membrane fouling propensity in membrane bioreactors (MBRs) was investigated. Four MBRs were operated at different mechanical mixing conditions. The control reactor (MBR0) was operated with aeration only supplemented by mechanical stirring at 150, 300, and 450 rpm in MBR150, MBR300, and MBR450, respectively. It was found that the MBR300 demonstrated minimum rate of membrane fouling. The fouling potential of the MBR300 mixed liquor was lowest characterized by the specific cake resistance and the normalized capillary suction time (CSTN). Moreover, it was found that the mean particle size reduced with an increase in the shear intensity. These results reveal that membrane fouling can be significantly mitigated by appropriate shear stress on membrane fibers induced by mechanical mixing condition.

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The hypothesis that heavy fishing pressure has led to changes in the biological characteristics of the estuary cobbler (Cnidoglanis macrocephalus) was tested in a large seasonally open estuary in southwestern Australia, where this species completes its life cycle and is the most valuable commercial fish species. Comparisons were made between seasonal data collected for this plotosid (eeltail catfish) in Wilson Inlet during 2005-08 and those recorded with the same fishery-independent sampling regime during 1987-89. These comparisons show that the proportions of larger and older individuals and the catch rates in the more recent period were far lower, i.e., they constituted reductions of 40% for fish ≥430 mm total length, 62% for fish ≥4 years of age, and 80% for catch rate. In addition, total mortality and fishing-induced mortality estimates increased by factors of ~2 and 2.5, respectively. The indications that the abundance and proportion of older C. macrocephalus declined between the two periods are consistent with the perception of long-term commercial fishermen and their shift toward using a smaller maximum gill net mesh to target this species. The sustained heavy fishing pressure on C. macrocephalus between 1987-89 and 2005-08 was accompanied by a marked reduction in length and age at maturity of this species. The shift in probabilistic maturation reaction norms toward smaller fish in 2005-08 and the lack of a conspicuous change in growth between the two periods indicate that the maturity changes were related to fishery-induced evolution rather than to compensatory responses to reduced fish densities.

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Purpose – Homeownership is considered both economically and socially beneficial for homeowners. However, in the collective living arrangement, reaching a consensus with regard to the residential environment is difficult. The purpose of this paper is to identify factors that can reduce the conflict among the stakeholders in multi-owner low-cost housing in Malaysia.
Design/methodology/approach – This study tested three hypotheses examining whether the demographic and socio-economic characteristics of owner-occupants and occupancy rates affect owner-occupants' satisfaction with stakeholders' relationships. Data were collected through questionnaires from owner-occupants of multi-owner low-cost settlements in Selangor state. Data on housing characteristics were collected from chairpersons of the respective owners' organisations. The data were treated as parametric, and analysis of variance was conducted.
Findings – Four factors – number of children in the family, duration of residency, participation in social activities and participation in meetings – were found to affect owners-occupants' satisfaction with the stakeholders' relationships. The significant effect of occupancy rates was also indicated.
Practical implications – The Management Corporations (MCs) should encourage social relationships among residents. To avoid conflict, the costs and benefits of participation must be balanced. Policy makers should take two key aspects seriously: owner-managed strategy practices by the MCs and high rates of tenant-residents. A mechanism should be identified for assisting the MCs in housing management and for protecting the benefits of homeownership for owner-occupants.
Originality/value – Past studies on low-income household settlements examined public housing or low-income homeowners of single detached dwellings. This study adds to the existing body of knowledge by examining low-income homeowners in multi-owner low-cost settlements.

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Background: Urban and rural communities differ in the incidence of several diseases including coronary heart disease and some cancers. Lower hip fracture rates among rural than urban populations have been reported but few studies have compared rural and urban fractures at sites other than the hip.

Objective: To compare total and site specific fracture rates among adult residents of rural and urban communities within the same population.

Design and setting: This is a population based study on osteoporosis in Australia. All fractures occurring in adult residents over a two year period were ascertained using radiological reports. The rural and urban areas are in close proximity, with the same medical, hospital, and radiological facilities permitting uniform fracture ascertainment.

Main outcome measures: All fracture rates were age adjusted and sex adjusted to the Australian population according to the 1996 census of the Australian Bureau of Statistics and described as the rate per 10 000 person years. The p values refer to the adjusted rate difference.

Results:
The hip fracture rate (incidence per 10 000 person years) was 32% lower (39 v 57, p<0.001), and the total fracture rate 15% lower (160 v 188, p=0.004) among rural than urban residents, respectively. The lower fracture rates in the rural population were also apparent for pelvic fractures.

Conclusion:
In the older rural population, lower fracture rates at sites typically associated with osteoporosis suggest environmental factors may have a different impact on bone health in this community. If the national rate of hip fracture could be reduced to that of the rural population, the projected increase in hip fracture number attributable to aging of the population could be prevented.