30 resultados para decomposition of a support

em University of Queensland eSpace - Australia


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The turbostratic mesoporous carbon blacks were prepared by catalytic chemical vapour decomposition (CCVD) of acetylene using Ni/MgO catalysts prepared by co-precipitation. The relationship between deposition conditions and the nanostructures of resultant carbon black materials was investigated. It was found that the turbostratic and textural structures of carbon blacks are dependent on the deposition temperature and nickel catalyst loading. Higher deposition temperature increases the carbon crystallite unit volume V-nano and reduces the surface area of carbon samples. Moreover, a smaller V-nano is produced by a higher Ni loading at the same deposition temperature. In addition of the pore structure and the active metal surface area of the catalyst, the graphitic degree or electronic conductivity of the carbon support is also a key issue to the activity of the supported catalyst. V-nano is a very useful parameter to describe the effect of the crystalline structure of carbon blacks on the reactivity of carbon blacks in oxygen-carbon reaction and the catalytic activity of carbon-supported catalyst in ammonia decomposition semi-quantitatively. (C) 2006 Elsevier B.V. All rights reserved.

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Using a computer keyboard with the forearms unsupported has been proposed as a causal factor for neck/shoulder and arm/hand diagnoses. Recent laboratory and field studies have demonstrated that forearm support might be preferable to working in the traditional floating posture. The aim of this study was to determine whether providing forearm Support when using a normal computer workstation would decrease musculoskeletal discomfort in intensive computer users in a call centre. A randomised controlled study (n = 59), of 6 weeks duration was conducted. Thirty participants (Group 1) were allocated to forearm support using the desk surface with the remainder (Group 2) acting as a control group. At 6 weeks, the control group was also set up with forearm support. Both groups were then monitored for another 6 weeks. Questionnaires were used at 1, 6 and 12 weeks to obtain information about discomfort, workstation setup, working posture and comfort. Nine participants (Group 1 n = 6, Group 2 n = 3) withdrew within a week of commencing forearm support either due to discomfort or difficulty in maintaining the posture. At 6 weeks, the group using forearm support generated significantly fewer reports of discomfort in the neck and back, although the difference between the groups was not statistically significant. At 12 weeks, there were fewer reports of neck, back and wrist discomfort when preintervention discomfort was compared with post intervention discomfort. These findings indicate that for the majority of users, forearm support may be preferable to the floating Posture implicit in current guidelines for computer workstation setup. (C) 2004 Elsevier Ltd. All rights reserved.

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After providing background on Dendrolagus species in Australia, two consecutive surveys of Brisbane's residents are used to assess public knowledge of tree-kangaroos and the stated degree of support for their conservation in Australia. The responses of participants in Survey I are based on their pre-survey knowledge of wildlife. The same set of participants completed Survey II after being provided with additional information on all the wildlife species mentioned in Survey I. Changes in the attitudes of respondents and their degree of support for the protection and conservation of Australia's tree-kangaroos are measured, including changes in their contingent valuations and stated willingness to provide financial support for such conservation. Reasons for wanting to protect tree-kangaroos are specified and analysed. Furthermore, changes that occur in the relative importance of these reasons with increased knowledge are also examined. Support for the conservation of tree-kangaroos is found to rise with the additional knowledge supplied about all species and is compared with variations in support for protection of other mammals. Support for the conservation of Australia's less well known tropical mammals is found to increase relative to better known mammals (icons) present in temperate areas, such as koalas and red kangaroos. Possible implications of the results for government conservation policies in Australia are examined.

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We give a detailed exposition of the theory of decompositions of linearised polynomials, using a well-known connection with skew-polynomial rings with zero derivative. It is known that there is a one-to-one correspondence between decompositions of linearised polynomials and sub-linearised polynomials. This correspondence leads to a formula for the number of indecomposable sub-linearised polynomials of given degree over a finite field. We also show how to extend existing factorisation algorithms over skew-polynomial rings to decompose sub-linearised polynomials without asymptotic cost.

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Recent research involving starch grains recovered from archaeological contexts has highlighted the need for a review of the mechanisms and consequences of starch degradation specifically relevant to archaeology. This paper presents a review of the plant physiological and soil biochemical literature pertinent to the archaeological investigation of starch grains found as residues on artefacts and in archaeological sediments. Preservative and destructive factors affecting starch survival, including enzymes, clays, metals and soil properties, as well as differential degradation of starches of varying sizes and amylose content, were considered. The synthesis and character of chloroplast-formed 'transitory' starch grains, and the differentiation of these from 'storage' starches formed in tubers and seeds were also addressed. Findings of the review include the higher susceptibility of small starch grains to biotic degradation, and that protective mechanisms are provided to starch by both soil aggregates and artefact surfaces. These findings suggest that current reasoning which equates higher numbers of starch grains on an artefact than in associated sediments with the use of the artefact for processing starchy plants needs to be reconsidered. It is argued that an increased understanding of starch decomposition processes is necessary to accurately reconstruct both archaeological activities involving starchy plants and environmental change investigated through starch analysis. (C) 2004 Elsevier Ltd. All rights reserved.

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Information on decomposition of harvest residues may assist in the maintenance of soil fertility in second rotation (2R) hoop pine plantations (Araucaria cunninghamii Aiton ex A. Cunn.) of subtropical Australia. The experiment was undertaken to determine the dynamics of residue decomposition and fate of residue-derived N. We used N-15-labeled hoop pine foliage, branch, and stem material in microplots, over a 30-mo period following harvesting. We examined the decomposition of each component both singly and combined, and used C-13 cross-polarization and magic-angle spinning nuclear magnetic resonance (C-13 CPMAS NMR) to chart C transformations in decomposing foliage. Residue-derived N-15 was immobilized in the 0- to 5-cm soil layer, with approximately 40% N-15 recovery in the soil from the combined residues by the end of the 30-mo period. Total recovery of N-15 in residues and soil varied between 60 and 80% for the combined-residue microplots, with 20 to 40% of the residue N-15 apparently lost. When residues were combined within microplots the rate of foliage decomposition decreased by 30% while the rate of branch and stem decomposition increased by 50 and 40% compared with rates for these components when decomposed separately. Residue decomposition studies should include a combined-residue treatment. Based on C-15 CPMAS NMR spectra for decomposing foliage, we obtained good correlations for methoxyl C, aryl C, carbohydrate C and phenolic C with residue mass, N-15 enrichment, and total N. The ratio of carbohydrate C to methoxyl C may be useful as an indicator of harvest residue decomposition in hoop pine plantations.

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As the number of women surviving breast cancer increases, with implications for the health system, research into the physical and psychosocial sequelae of the cancer and its treatment is a priority. This research estimated self-reported health-related quality of life (HRQoL) associated with two rehabilitation interventions for breast cancer survivors, compared to a non-intervention group. Women were selected if they received an early home-based physiotherapy intervention (DAART, n = 36) or a group-based exercise and psychosocial intervention (STRETCH, n = 31). Questionnaires on HRQoL, using the Functional Assessment of Cancer Therapy - Breast Cancer plus Arm Morbidity module, were administered at pre-, post-intervention, 6- and 12-months post-diagnosis. Data on a non-intervention group (n = 208) were available 6- and 12-months post-diagnosis. Comparing pre/post-intervention measures, benefits were evident for functional well-being, including reductions in arm morbidity and upper-body disability for participants completing the DAART service at one-to-two months following diagnosis. In contrast, minimal changes were observed between pre/post-intervention measures for the STRETCH group at approximately 4-months post-diagnosis. Overall, mean HRQoL scores (adjusted for age, chemotherapy, hormone therapy, high blood pressure and occupation type) improved gradually across all groups from 6- to 12-months post-diagnosis, and no prominent differences were found. However, this obscured declining HRQoL scores for 20-40% of women at 12 months post-diagnosis, despite receiving supportive care services. Greater awareness and screening for adjustment problems among breast cancer survivors is required throughout the disease trajectory. Early physiotherapy after surgery has the potential for short-term functional, physical and overall HRQoL benefits.

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The present study aimed to evaluate the role of social support and self-efficacy on the level of stress associated with the transition from high school to university. One hundred and eight-five university students who had completed high school in the previous year completed a three-part questionnaire designed to gather information on their levels of self-efficacy, social support, and stress associated with their transition. The results showed that self-efficacy was a significant predictor of stress associated with the transition to university in that higher levels of self-efficacy were associated with lower levels of stress while social support was a non-significant predictor of stress. [Author abstract]

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We surveyed 204 individuals from the general public in Brisbane, Australia, to ascertain the extent to which they liked or disliked 24 species of wildlife (belonging to three classes: mammals, birds and reptiles) present in tropical Australia. We calculated likeability indices for each species. We also asked respondents if they favored the survival of each of these species, and were able to calculate the percentage of respondents favoring survival of each. Using linear regression analysis, we could relate the percentage of respondents favoring survival of each of the species to their indices of likeability. In addition, we compared the mean likeability of species in the three classes (mammals, birds and reptiles) with the respondents' allocation of funds (hypothetical 1,000 Australian dollars) between conservation of species and a human charity. From this, we were able to assess how important stated likeability is for preferences to conserve species by animal class, and reconsidered the hypothesis in the literature that there is likely to be more public support for the survival of mammals than for birds, and more support for the survival of birds than for reptiles.

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Necessary conditions for the complete graph on n vertices to have a decomposition into 5-cubes are that 5 divides it - 1 and 80 divides it (it - 1)/2. These are known to be sufficient when n is odd. We prove them also sufficient for it even, thus completing the spectrum problem for the 5-cube and lending further weight to a long-standing conjecture of Kotzig. (c) 2005 Wiley Periodicals, Inc.

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The circulant graph Sn, where S ⊆ Zn \ {0}, has vertex set Zn and edge set {{x, x + s}|x ∈ Zn, s ∈ S}. It is shown that there is a Hamilton cycle decomposition of every 6-regular circulant graph Sn in which S has an element of order n.