25 resultados para environmental factor

em Deakin Research Online - Australia


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Women living in socioeconomically disadvantaged neighbourhoods are at heightened risk for physical inactivity, but little is known about the correlates of physical activity among this group. Using a social-ecological framework, this study aimed to determine the individual, social and neighbourhood environmental correlates of physical activity amongst women living in such neighbourhoods. During 2007–2008 women (n = 4108) aged 18–45 years randomly selected from urban and rural neighbourhoods of low socioeconomic status in Victoria, Australia completed the International Physical Activity Questionnaire (long). They reported on individual (self-efficacy, enjoyment, intentions, outcome expectancies, skills), social (childcare, social support from family and friends/colleagues, dog ownership) and neighbourhood environmental (neighbourhood cohesion, aesthetics, personal safety, ‘walking environment’) factors. Multinomial logistic regression was used to examine the odds of increasing categories of leisure time physical activity (LTPA) and transport-related physical activity (TRPA) for each individual, social and environmental factor. In partially adjusted analyses, all individual, social and environmental variables were positively associated with LTPA, while all individual factors, family and friend support and the walking environment were positively associated with TRPA. In fully adjusted multivariable models, all individual and social factors remained significantly associated with LTPA, while self-efficacy, enjoyment, intentions, social support, and neighbourhood ‘walking environment’ variables remained significantly associated with TRPA. In conclusion, individual and social factors were most important for LTPA, while individual, social and neighbourhood environmental factors were all associated with TRPA. Acknowledging the cross-sectional design, the findings highlight the importance of different levels of potential influence on physical activity in different domains, which should be considered when developing strategies to promote physical activity amongst women living in socioeconomically disadvantaged neighbourhoods.

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Hemoglobin (Hb) polymorphism in cod is associated with temperature‐related differences in biogeographical distribution, and several authors have suggested that functional characteristics of the various hemoglobin isoforms (HbIs) directly influence phenotypic traits such as growth rate. However, no study has directly examined whether Hb genotype translates into physiological differences at the whole animal level. Thus, we generated a family of juvenile Atlantic cod consisting of all three main Hb genotypes (HbI‐1/1, HbI‐2/2, and HbI‐1/2) by crossing a single pair of heterozygous parents, and we compared their metabolic and cortisol responses to an acute thermal challenge (10°C to their critical thermal maximum [CTM] or 22°C, respectively) and tolerance of graded hypoxia. There were no differences in routine metabolism (at 10°C), maximum metabolic rate, metabolic scope, CTM (overall mean 22.9° ± 0.2°C), or resting and poststress plasma cortisol levels among Hb genotypes. Further, although the HbI‐1/1 fish grew more (by 15%–30% during the first 9 mo) when reared at 10° ± 1°C and had a slightly enhanced hypoxia tolerance at 10°C (e.g., the critical O2 levels for HbI‐1/1, HbI‐2/2, and HbI‐1/2 cod were 35.56% ± 1.24%, and 40.20% ± 1.99% air saturation, respectively), these results are contradictory to expectations based on HbI functional properties. Thus, our findings (1) do not support previous assumptions that growth rate differences among cod Hb genotypes result from a more efficient use of the oxygen supply—that is, reduced standard metabolic rates and/or increased metabolic capacity—and (2) suggest that in juvenile cod, there is no selective advantage to having a particular Hb genotype with regards to the capacity to withstand ecologically relevant environmental challenges.

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When Rhododendron pollen tubes are cultured in the dark, electron-dense bodies are present that appear to be a metabolically altered form of a proplastid that is difficult to fix for electron microscopy, and whose membranes may not be intact. When similar pollen tubes are cultured in a dark/light regime, ultrastructurally well-defined proplastids are present after fixation in glutaraldehyde with PIPES buffer and tannic acid, followed by osmic acid. This fixation technique also gave the best ultrastructural images of those proplastids in pollen tubes grown in the dark. Pollen tube plastids have the potential to become chromoplasts when cultured in a dark/light regime as evidenced by the presence of branched tubules characteristic of these organelles. Light appears to be a hitherto neglected environmental factor involved in regulating pollen tube growth. This improved fixation procedure demonstrates the bilayered nature of the membranes surrounding sperm cells and the existence of cytoplasmic channels connecting sperm cell and pollen tube plasma membranes.

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Introduction Improving infrastructure to support walking and cycling is often regarded as fundamental to encouraging their widespread uptake. However, there is little evidence that specific provision of this kind has led to a significant increase in walking or cycling in practice, let alone wider impacts such as changes in overall physical activity or carbon emissions. Connect2 is a major new project that aims to promote walking and cycling in the UK by improving local pedestrian and cycle routes. It therefore provides a useful opportunity to contribute new evidence in this field by means of a natural experimental study.

Methods and analysis iConnect is an independent study that aims to integrate the perspectives of public health and transport research on the measurement and evaluation of the travel, physical activity and carbon impacts of the Connect2 programme. In this paper, the authors report the study design and methods for the iConnect core module. This comprised a cohort study of residents living within 5 km of three case study Connect2 projects in Cardiff, Kenilworth and Southampton, supported by a programme of qualitative interviews with key informants about the projects. Participants were asked to complete postal questionnaires, repeated before and after the opening of the new infrastructure, which collected data on demographic and socioeconomic characteristics, travel, car fuel purchasing and physical activity, and potential psychosocial and environmental correlates and mediators of those behaviours. In the absence of suitable no-intervention control groups, the study design drew on heterogeneity in exposure both within and between case study samples to provide for a counterfactual.

Ethics and dissemination The study was approved by the University of Southampton Research Ethics Committee. The findings will be disseminated through academic presentations, peer-reviewed publications and the study website (http://www.iconnect.ac.uk) and by means of a national seminar at the end of the study.

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Experimental evidence of environmental features important for physical activity is challenging to procure in real world settings. The current study aimed to investigate the causal effects of environmental modifications on a photographed street's appeal for older adults' walking for transport. Secondly, we examined whether these effects differed according to gender, functional limitations, and current level of walking for transport. Thirdly, we examined whether different environmental modifications interacted with each other. Qualitative responses were also reported to gain deeper insight into the observed quantitative relationships. Two sets of 16 panoramic photographs of a streetscape were created, in which six environmental factors were manipulated (sidewalk evenness, traffic level, general upkeep, vegetation, separation from traffic, and benches). Sixty older adults sorted these photographs on appeal for walking for transport on a 7-point scale and reported qualitative information on the reasons for their rankings. Sidewalk evenness appeared to have the strongest influence on a street's appeal for transport-related walking. The effect of sidewalk evenness was even stronger when the street's overall upkeep was good and when traffic was absent. Absence of traffic, presence of vegetation, and separation from traffic also increased a street's appeal for walking for transport. There were no moderating effects by gender or functional limitations. The presence of benches increased the streetscape's appeal among participants who already walked for transport at least an hour/week. The protocols and methods used in the current study carry the potential to further our understanding of environment-PA relationships. Our findings indicated sidewalk evenness as the most important environmental factor influencing a street's appeal for walking for transport among older adults. However, future research in larger samples and in real-life settings is needed to confirm current findings.

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Abstract constructivism, as a set of theories about how learners learn, has been an important discourse in the educational research literature for a number of years. Interestingly, it has been far more visible in science education research than in environmental education research. This article considers conceptual change theory within constructivism as a contested concept, outlines differing expressions of constructivism in science education and environmental education, and argues for approaches to environmental education that adopt socially constructivist perspectives with respect to the character of the subject matter content as well as to learners' apprehension of such content. In considering implications for research, this perspective is juxtaposed with a recent United States Education Act, which prescribes a far more objectivist approach to educational research and which serves as a reminder that research itself is a powerful factor in shaping how the nature of subject matter is constructed, learning and the implications of these for teaching practice.

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The nature and extent of environmental reporting within the annual reports of four Australian state government departments over a six year period from 2000-2006 is examined in this study. The Victorian Government Department of Sustainability and Environment (DSE), the New South Wales Department of Energy, Utilities and Sustainability (DEUS), the South Australian Department for Environment and Heritage (DEH) and the Tasmanian Department of Primary Industries, Water and Environment (DPIWE) have been selected. These departments are responsible for environmentally sensitive areas such as conservation, water management and public land management. The nature of these areas is a factor which might potentially affect disclosure practices so it might be expected that these departments disclose more environmental information than departments in less environmentally and politically sensitive areas. These departments also have a number of politically active stakeholder groups, including Aboriginal communities and organisations, environmental groups and forest and timber industries. This study found a reduction in environmental reporting after a five year period of increases.

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While the cause of Parkinson's disease (PD) remains unknown, recent evidence suggests certain environmental factors, such as well water drinking, herbicides and pesticides exposure, and neurotoxins, may trigger the chain of oxidative reactions culminating in the death of dopaminergic neurons in substantia nigra to cause parkinsonism. Most studies to date focused on PD with old age onset. However, there is a peculiar group of parkinsonian patients, the young onset Parkinson's disease (YOPD), in whom the age of onset is before 40. It is intriguing to know whether earlier exposure to the putative neurotoxin(s) may contribute to the earlier onset. We therefore conducted this case-control study in which 60 PD patients, 30 YOPD patients and the same number of age- and sex-matched young controls were included. Using logistic regression, we found well water drinking and head injury were risk factors for the development of YOPD. When YOPD patients were compared with PD, we found head injury and exercise were the significant predictors. Keeping all other variables constant, head injury was a risk factor and exercise appeared to be a protective factor. We conclude early exposure to well water drinking and head trauma may trigger and expedite the appearance of parkinsonian features, but such acceleration may be prevented through regular exercise.

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Constructivism, as a set of theories about how learners learn, has been an important discourse in the educational research literature for a number of years. Interestingly, it has been far more visible in science education research than in environmental education research. This article considers conceptual change theory within constructivism as a contested concept, outlines differing expressions of constructivism in science education and environmental education, and argues for approaches to environmental education that adopt socially constructivist perspectives with respect to the character of the subject matter content as well as to learners' apprehension of such content. In considering implications for research, this perspective is juxtaposed with a recent United States Education Act, which prescribes a far more objectivist approach to educational research and which serves as a reminder that research itself is a powerful factor in shaping how we construct the nature of subject matter, learning and the implications of these for teaching practice.

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Goat fibre production is affected to a similar extent by genetic and environmental influences. Environmental influences include bio-geophysical factors (photoperiod, climate-herbage system and soil-plant trace nutrient composition), country of origin, nutrition factors (live weight, growth patterns) and management factors (farm, herd age and sex structure). Nutrition and management influences discussed include rate of stocking, energy nutrition, live weight change, parturition and management during shearing. The nutritional variation within and among years is the most important climatic factor influencing cashmere production, fibre diameter and fibre curvature (crimp). With productive cashmere goats, large responses to energy supplementation have been measured with optimum nutritional management. The effects and importance of management and hygiene during fibre harvesting (shearing) in producing quality fibre are emphasised.

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he prominence of global warming as an environmental issue has illustrated the close relationship between natural resources, ecosystems and global security. Whilst environmental decision making often uses techniques such as economic valuation and risk management, the security component is often not considered, at least not from a security analyst’s perspective. Yet environmental security considerations can be global, regional and/or national in impact. Environmental change and policy can effect human health and well being as well as initiating conflict; it can affect the existence of life itself. These aspects are firmly in the domain of the security discipline although the protection of the global ecosystem has not traditionally been considered by those who create security policy. The idea of environmental/ecological security ranges from the eco-centric approach which examines the impact of human activities that impact on the security of the natural systems to the more traditional anthropocentric perspectives that look at varied issues such as conflict caused by natural resource competition and environmental degradation, and the greening of military operations. This paper will assert that the inclusion of the security factor in policy creation and environmental assessments is essential to give richer solutions to these complex socio-economic and ecological situations. Systems theory over the last few decades has emphasised the inclusion of as many perspectives on messy problems as possible to provide truly systemic outcomes. It is posited that the addition of such concepts as threat analyses will produce more effective and sustainable outcomes.

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It is well established in genetic epidemiology that family history is an important indicator of familial aggregation of disease in a family. A strong genetic risk factor or an environmental risk factor with high familial correlation can result in a strong family history. In this paper, family history refers to the number of first-degree relatives affected with the disease. Cui and Hopper (Journal of Epidemiology and Biostatistics 2001; 6: 331-342) proposed an analytical relationship between family history and relevant genetic parameters. In this paper we expand the relationship to both genetic and environmental risk factors. We established a closed-form formula for family history as a function of genetic and environmental parameters which include genetic and environmental relative risks, genotype frequency, prevalence and familial correlation of the environmental risk factor. The relationship is illustrated by an example of female breast cancer in Australia. For genetic and environmental relative risks less than 10, most of the female breast cancer cases occur between the age of 40 and 60 years. A higher genetic or environmental relative risk will move the peak of the distribution to a younger age. A more common disease allele or more prevalent environmental risk factor will move the peak to an older age. For a proband with breast cancer, it is most likely (with probability ge80%) that none of her first-degree relatives is affected with the disease. To enable the probability of having a positive family history to reach 50%, the environmental relative risks must be extremely as high as 100, the familial correlation as high as 0.8 and the prevalence as low as 0.1. For genetic risk alone, even the relative risk is as high as 100, the probability of having a positive family history can only reach about 30%. This suggests that the environmental risk factor seems to play a more important role in determining a strong family history than the genetic risk factor.

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Genetic and environmental influences on variation in balance performance were measured in 93 monozygous and 83 dizygous female twin pairs aged 21–82 years (mean age, 50.5 years) in Melbourne, Australia, between 1999 and 2003. The authors administered clinical (Lord's Balance Test and Step Test) and laboratory tests of static and dynamic balance from the Chattecx Balance System with and without distractor tasks. The authors conducted factor analysis and estimated genetic and environmental variance components and heritability (defined as additive genetic variance as a proportion of all variance, after adjustment for age) using a multivariate normal model with the statistical package FISHER. Three factors were identified and adjusted for age. Heritability was 46% (standard error (SE), 9) for the "sensory balance tests" factor and 30% (SE, 9) for the "static and dynamic perturbations" factor. For both factors, the remaining variance was attributed to unique environmental effects. There was no evidence that genetic factors influenced variation in the "dynamic weight shift tests" factor, with environmental effects shared by twins accounting for 38% (SE, 7) of variance. Neither genetic nor environmental proportions of variance differed significantly between twin subgroups by age (≤50/>50 years). An age-related decline in performance measures was found across the whole sample. These results imply that balance impairments may have a heritable element.

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Background : Insufficient participation in physical activity and excessive screen time have been observed among Chinese children. The role of social and environmental factors in shaping physical activity and sedentary behaviors among Chinese children is under-investigated. The purpose of the present study was to assess the reliability and validity of a questionnaire to measure child- and parent-reported psychosocial and environmental correlates of physical activity and screen-based behaviors among Chinese children in Hong Kong.

Methods :
A total of 303 schoolchildren aged 9-14 years and their parents volunteered to participate in this study and 160 of them completed the questionnaire twice within an interval of 10 days. Intraclass correlation coefficients (ICCs), kappa statistics, and percent agreement were performed to evaluate test-retest reliability of the continuous and categorical variables, respectively. Exploratory factor analyses (EFAs) were conducted to assess convergent validity of the emergent scales. Cronbach's alpha and ICCs were performed to assess internal and test-retest reliability of the emergent scales. Criterion validity was assessed by correlating psychosocial and environmental measures with self-reported physical activity and screen-based behaviors, measured by a validated questionnaire.

Results :
Reliability statistics for both child- and parent-reported continuous variables showed acceptable consistency for all of the ICC values greater than 0.70. Kappa statistics showed fair to perfect test-retest reliability for the categorical items. Adequate internal consistency and test-retest reliability were observed in most of the emergent scales. Criterion validity assessed by correlating psychosocial and environmental measures with child-reported physical activity found associations with physical activity in the self-efficacy scale (r = 0.25, P < 0.05), the peer support for physical activity scale (r = 0.25, P < 0.05) and home physical activity environmental (r = 0.14, P < 0.05). Children's screen-based behaviors were associated with the family support for physical activity scale (r = -0.22, P < 0.05) and parental role modeling of TV (r = 0.12, P = 0.053).

Conclusions :
The findings provide psychometric support for using this questionnaire for examining psychosocial and environmental correlates of physical activity and screen-based behaviors among Chinese children in Hong Kong. Further research is needed to develop more robust measures based on the current questionnaire, especially for peer influence on physical activity and parental rules on screen-based behaviors.

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Goat fibre production is affected by genetic and environmental influences. Environmental influences which are the subject of this review include bio–geophysical factors (photoperiod, climate–herbage system and soil–plant trace nutrient composition), nutrition factors and management factors. Nutrition and management influences discussed include rate of stocking, supplementary feeding of energy and protein, liveweight change, parturition and management during shearing. While experimental data suggest affects of seasonal photoperiod on the growth of mohair and cashmere are large, these results may have confounded changes in temperature with photoperiod. The nutritional variation within and among years is the most important climatic factor influencing mohair and cashmere production and quality. Mohair quality and growth is affected significantly by rate of stocking and during periods of liveweight loss by supplementary feeding of either energy or protein. Strategic use of supplements, methods for rapid introduction of cereal grains, influence of dietary roughage on intake and the economics of supplementary feeding are discussed. Cashmere production of young, low producing goats does not appear to be affected by energy supplementation, but large responses to energy supplementation have been measured in more productive cashmere goat strains. The designs of these cashmere nutrition experiments are reviewed. Evidence for the hypothesis that energy-deprived cashmere goats divert nutrients preferentially to cashmere growth is reviewed. The influence and potential use of liveweight manipulation in affecting mohair and cashmere production and quality are described. Estimates of the energy requirements for the maintenance of fibre goats and the effect of pregnancy and lactation on mohair and cashmere growth are summarised. The effects and importance of management and hygiene during fibre harvesting (shearing) in producing quality fibre is emphasised. The review concludes that it is important to assess the results of scientific experiments for the total environmental content within which they were conducted. The review supports the view that scientific experiments should use control treatments appropriate to the environment under study as well as having controls relevant for other environments. In mediterranean and annual temperate environments, appropriate controls are liveweight loss and liveweight maintenance treatments. Mohair producers must graze goats at moderate rates of stocking to maximise animal welfare, but in so doing, they will produce heavier goats and coarser mohair. In mediterranean and annual temperate environments, seasonal changes in liveweight are large and influence both quality and production of mohair and cashmere. Mohair and cashmere producers can manipulate liveweight by supplementary feeding energy during dry seasons to minimise liveweight loss, but the economics of such feeding needs to be carefully examined. Strategic benefits can be obtained by enhancing the growth of young does prior to mating and for higher producing cashmere goats.