50 resultados para Environmental effect

em Deakin Research Online - Australia


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The relative importance and relationship between psychological and situational factors in predicting commuter-transport-mode choice was tested by four hypotheses. First, the influence of individuals’ values on commuter behavior is mediated by their corresponding beliefs about the environmental threat of cars (mediation hypothesis). Second, the influence of these beliefs on behavior is moderated by individual consideration of future consequences and control beliefs (moderation hypothesis). Third, cost, time, and access factors contribute to individuals’ commuter choice (situational hypothesis). Fourth, situational and psychological factors jointly influence proenvironmental behavior (interaction hypothesis). A sample of 205 Australian university students completed a survey to measure these relationships. Regression analyses indicated support for the mediation, situational, and interaction hypotheses. It was concluded that to achieve a transport-mode shift to public transport, public policy strategies should focus on individuals’ transport-related environmental beliefs (personal control and environmental effect of cars) and situations (access to public transport at reduced cost).

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A series of field surveys were carried out on two permanent pools of the upper Glenelg River in SW Victoria, Australia. One was representative of the wider and deeper pools while the other was representative of the more-narrow and shallower pools. Both pools showed a typical seasonal cycle of warm, brackish, oxygen-poor, summer conditions and cool, oxygen-rich, low-salinity, winter conditions. The summer salinity increases were larger than expected, suggesting possible saline groundwater inflow from unidentified springs. Both pools contained anoxic water in their deeper sections but this was permanent only in the deeper pool. A simple model of the flushing rate of such anoxic pools subject to flows, such as environmental flow releases, was developed, based on an energy balance between the potential energy required to lift the anoxic layer and the kinetic energy derived from the river flow. The results were tested against and in agreement with the field measurements. The model also suggests that the anoxic layers are resilient to all but the largest environmental flows.

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The intensity of sexual selection is influenced by environmental conditions because these conditions influence signal propagation and the risks of the signal being exploited by predators and parasites. We explore the possibility that spatial or temporal heterogeneity in environmental signalling conditions (in this case light spectrum) may induce fluctuating sexual selection on male behaviour and ornamentation in guppies. We used shade cloth and filters to experimentally manipulate light spectrum, mimicking conditions found naturally: early morning/late afternoon light (SC treatment), midday forest shade (F89 filter treatment) and midday woodland shade (F55 filter treatment). Females were more responsive to male courtship and males were less likely to attempt sneak copulations under F55 light than the other two treatments. By contrast, male display rate was not influenced by treatment. Females tended to prefer the same males under SC and F55 light, but attractiveness in these treatments was unrelated to attractiveness under F89 light. There were similarities among treatments in the traits that females preferred: females preferred males with larger areas of orange in all three treatments. There were, however, also some differences, including preference for larger males under F89 light and for smaller males under the other treatments. Overall, the influence of ambient light spectrum on the relative importance of mate choice and male sneak copulation may have important implications for the mode and strength of sexual selection in different environments. The findings on attractiveness and preference functions, however, suggest that light spectrum only weakly affects the direction of sexual selection by female choice.

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Air temperature, pressure and humidity are environmental factors that affect air density and therefore the relationship between a cyclist’s power output and their velocity. These environmental factors are changeable and are routinely quite different at elite cycling competitions conducted around the world, which means that they have a variable effect on performance in timed events. The present work describes a method of calculating the effect of these environmental factors on timed cycling events and illustrates the magnitude and significance of these effects in a case study. Formulas are provided to allow the calculation of the effect of environmental conditions on performance in a time trial cycling event. The effect of environmental factors on time trial performance can be in the order of 1.5%, which is significant given that the margins between ranked performances is often less than this. Environmental factors may enhance or hinder performance depending upon the conditions and the comparison conditions. To permit the fair comparison of performances conducted in different environmental conditions, it is recommended that performance times are corrected to the time that would be achieved in standard environmental conditions, such as 20 oC, 760 mmHg (1013.25 hPa) and 50% RH.

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Purpose. This study examined the usefulness of contextual cues in enhancing the accuracy of children's narrative accounts of an occurrence of a repeated event.

Method. Children aged 6 to 7 years took part in the same staged event four times whereby 16 target details varied in each occurrence (e.g. the colour of a cloak varied each time). Three days later, the children's free recall of the final occurrence was elicited. This occurrence was identified in one of two ways. Either it was identified via the temporal term 'last', or else the term 'last' was combined with a feature related to the environmental context or setting that was unique to the occurrence (i.e., the interviewer referred to a new object that was worn throughout the occurrence or a new person who carried out the event). For each condition, performance was compared to that of children who experienced the event only once.

Results. Children's memory of details specific to the target occurrence was better after the single than the repeated event. However for both event types, children who were given the contextual and temporal cue performed better than those who were given the temporal cue only. The benefit of using a contextual cue did not result in an increase in errors.

Conclusion. Contextual cues (generated by an interviewer) can facilitate children's recall of an occurrence of an event. However, further research needs to determine whether this finding would generalize to a more practical situation where the child (rather than the interviewer) generates the cues.

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To investigate the influence of heat stress on the regulation of skeletal muscle carbohydrate metabolism, six active, but not specifically trained, men performed 5 min of cycling at a power output eliciting 70% maximal O(2) uptake in either 20 degrees C (Con) or 40 degrees C (Heat) after 20 min of passive exposure to either environmental condition. Although muscle temperature (T(mu)) was similar at rest when comparing trials, 20 min of passive exposure and 5 min of exercise increased (P < 0.05) T(mu) in Heat compared with Con (37.5 +/- 0.1 vs. 36.9 +/- 0.1 degrees C at 5 min for Heat and Con, respectively). Rectal temperature and plasma epinephrine were not different at rest, preexercise, or 5 min of exercise between trials. Although intramuscular glycogen phosphorylase and pyruvate dehydrogenase activity increased (P < 0.05) at the onset of exercise, there were no differences in the activities of these regulatory enzymes when comparing Heat with Con. Accordingly, glycogen use in the first 5 min of exercise was not different when comparing Heat with Con. Similarly, no differences in intramuscular concentrations of glucose 6-phosphate, lactate, pyruvate, acetyl-CoA, creatine, phosphocreatine, or ATP were observed at any time point when comparing Heat with Con. These results demonstrate that, whereas mild heat stress results in a small difference in contracting T(mu), it does not alter the activities of the key regulatory enzymes for carbohydrate metabolism or glycogen use at the onset of exercise, when plasma epinephrine levels are unaltered.

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Six endurance-trained men [peak oxygen uptake (VO2) = 4.58 ± 0.50 (SE) l/min] completed 60 min of exercise at a workload requiring 68 ± 2% peak VO2 in an environmental chamber maintained at 35°C (<50% relative humidity) on two occasions, separated by at least 1 wk. Subjects ingested either a 6% glucose solution containing 1 µCi [3-3H]glucose/g glucose (CHO trial) or a sweet placebo (Con trial) during the trials. Rates of hepatic glucose production [HGP = glucose rate of appearance (Ra) in Con trial] and glucose disappearance (Rd), were measured using a primed, continuous infusion of [6,6-2H]glucose, corrected for gut-derived glucose (gut Ra) in the CHO trial. No differences in heart rate, VO2, respiratory exchange ratio, or rectal temperature were observed between trials. Plasma glucose concentrations were similar at rest but increased (P < 0.05) to a greater extent in the CHO trial compared with the Con trial. This was due to the absorption of ingested glucose in the CHO trial, because gut Ra after 30 and 50 min (16 ± 5 µmol · kg-1 · min-1) was higher (P < 0.05) compared with rest, whereas HGP during exercise was not different between trials. Glucose Rd was higher (P < 0.05) in the CHO trial after 30 and 50 min (48.0 ± 6.3 vs 34.6 ± 3.8 µmol · kg-1 · min-1, CHO vs. Con, respectively). These results indicate that ingestion of carbohydrate, at a rate of ~1.0 g/min, increases glucose Rd but does not blunt the rise in HGP during exercise in the heat.

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Background: Exposure to other people’s cigarette smoke (environmental tobacco smoke, or ETS) is an important child health issue.
Objectives: To determine the effectiveness of interventions aiming to reduce exposure of children to ETS.
Search strategy: The Tobacco Addiction Group register of studies was searched.MEDLINE, EMBASE and four other health and psychology databases were searched electronically, bibliographies of retrieved primary studies were checked and specialists in the area consulted.
Selection criteria:
Controlled trials with or without random allocation were included in this review if they addressed participants (parents and other family members, child care workers and teachers) involved with the care and education of infants and young children (aged 0-12 years). All mechanisms for reduction of children’s environmental tobacco smoke exposure, and smoking prevention, cessation, and control programmes targeting these participants are included. These include smoke free policies and legislation, health promotion, social behavioural therapies, technology, education and clinical interventions.
Data collection and analysis: Two reviewers independently assessed studies and extracted data. Due to heterogeneity of methodologies and outcomes, no summary measures were possible and results were synthesised using narrative summaries.
Main results:
Nineteen studies met the inclusion criteria, one of which was subsequently excluded. Three interventions were targeted at populations or community settings, seven studies were conducted in the well child health care setting and eight in the ill child health care setting. Twelve of these studies are from North America. In 12 of the 18 studies there was reduction of ETS exposure for children in both intervention and comparison groups. In only four of the 18 studies was there a statistically significant intervention effect. Three of these successful studies employed intensive counselling interventions targeted to smoking parents. There is little difference between the well infant, child respiratory illness and other child illness settings as contexts for parental smoking cessation interventions. The fourth successful intervention was in the school setting targeting the ETS exposure of children from smoking fathers.
Authors’ conclusions: Brief counselling interventions, successful in the adult health setting when coming from physicians, cannot be extrapolated to adults in the setting of child health. There is limited support for more intensive counselling interventions. There is no clear evidence for differences between the respiratory, non-respiratory ill child, well child and peripartum settings as contexts for reduction of children’s ETS exposure.

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This study describes the macrophyte assemblages of temporary floodplain wetlands situated on the floodplain of the Murray River, southeast Australia. Wetlands in the study are subject to flooding, the frequency, duration, and magnitude of which are dictated by the current, regulated river-flow regime. Our aim was to examine the influence of the existing flooding regime on macrophyte assemblages and to trial a monitoring program, based on a multiple before-after-control-impact (MBACI) design, to detect the impact of proposed environmental water allocations (EWAs) on the wetlands. Two categories of flooding regime were identified based on the flow magnitudes required for flooding to occur (flooding thresholds). In this scheme, wetlands with relatively low flooding thresholds are classed as ‘impact’ and those with higher thresholds are classed as ‘control.’ The wetlands were surveyed over a two-year period that incorporated at least one wetting-drying cycle at all wetlands. Results showed significant differences between survey times (season and year), but differences between flooding regime categories were significant only for some components of macrophyte assemblages. Differences between survey dates appear to reflect largely short-term responses to the most recent flood events. However, macrophyte differences observed between control and impact wetlands reflected the cumulative effect of flood events over several years. Differences between control and impact wetlands were strongest for post-flooding surveys based on full assemblages (using ANOSIM) and among specific taxa and functional groups (using ANOVA). Power to detect differences between control and impact wetlands was greatest for species richness and total abundance, but taxa with low variability among wetlands, and hence good power, were actually less sensitive to hydrologic change. We conclude that the MBACI design used in this study will be most effective in detecting wetland ecosystem responses to the implementation of EWAs if response variables are carefully chosen based on their sensitivity to hydrologic change.

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This paper develops a causal model of environmental attitudes using measures of the dominant social paradigm of Western industrial societies. Four components of the DSP framework are examined with regard to environmental attitudes and perception of change using a sample of university students from Australia and New Zealand. The results indicate that one’s belief in the DSP has a negative effect on both environmental attitudes and perception of change necessary to ameliorate degradation of the environment. Thus, while public policy favors increasing awareness of and interest in the environment, policy instruments may remain ineffective in producing lasting change if the components of the DSP remain unchanged. It is argued that public policy ought to be directed at changing the DSP so that its negative effects will be minimized.

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This paper develops a causal model of environmental attitudes using measures of the dominant social paradigm (DSP) of western industrial societies. Two components of the DSP framework beliefs in economic growth and anthropocentrism are examined regards to environmental attitudes using a sample of university students from Australia and New Zealand. The results indicate that one’s belief in the DSP has a negative effect on environmental attitudes and perception of change necessary ameliorate degradation of the environment. Thus, while public policy favors increasing awareness of and interest in the environment, policy instruments may remain ineffective in producing lasting change if the components of the DSP remain unchanged. It is argued that public policy ought to be directed at changing the DSP so that its negative
effects will be minimized.

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In this paper we examine the role of environmental quality in determining per capita health expenditures. We take a panel cointegration approach in order to explore the possibility of estimating both short-run and long-run impacts of environmental quality. Our empirical analysis is based on eight OECD countries, namely Austria, Denmark, Iceland, Ireland, Norway, Spain, Switzerland, and the UK for the period 1980–1999. We find that per capita health expenditure, per capita income, carbon monoxide emissions, sulphur oxide emissions and nitrogen oxide emissions are panel cointegrated. While short-run elasticities reveal that income and carbon monoxide emissions exert a statistically significant positive effect on health expenditures, in the long-run in addition to income and carbon monoxide, we find that sulphur oxide emissions have a statistically significant positive impact on health expenditures.

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Small and medium sized enterprises (SMEs) are an important part of the world economy but they are thought to be responsible for around 60% of all carbon dioxide emissions by businesses in the UK and 70% of all pollution. SMEs often have major problems with limited resources, limited knowledge and limited technical capabilities to deal with their own environmental impact. SMEs exhibit widely differing characteristics and behaviours where environmental issues are concerned. Yet under these conditions they are all expected to engage in environmentally responsible business for the greater good of society. Interventions that encourage good environmental behaviour are often polarised between regulation and legislation at one extreme and voluntary environmental agreements at the other. It is clear that a holistic mixture of interventions is necessary to achieve maximum engagement by all SMEs. This paper categorises the main behaviours observed in SMEs towards environmental issues and develops a selection or 'tool kit' of intervention strategies that might be deployed within each category of SME for maximum effect.