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121.
Research has examined personal change and stability in early adulthood but generally with standardized scales and without inviting explicit comparison of self with other people. The present work uses the repertory grid method to examine how graduates construe themselves and others during early career. Ninety-four graduate entrants to a multinational corporation with zero to four years' tenure completed repertory grids on two occasions one year apart. Results shed much light on the graduates' concepts of self relative to others in their work setting, and how these change over time. The graduates generally had fairly positive self concepts, though these did not become more positive with tenure. Most saw themselves much as they thought others saw them. Change in concepts of self varied greatly between graduates, as did the constructs on which those concepts were described. The results cast further doubt on whether organizational socialization affects people in uniform ways.  相似文献   
122.
Objective: This article describes the patterns of self-reported driving under the influence of alcohol (DUIA) and driving under the influence of cannabis (DUIC) among licensed Ontario students in 2009 and examines their associations with graduated licensing, risk taking, and substance use problems for understanding DUIA and DUIC behaviors. Ontario's graduated licensing system requires new drivers to hold a G1 license for a minimum of 8 months and a G2 license for a minimum of 12 months before a full and unrestricted G license can be obtained. Among other restrictions, G1 drivers must maintain a 0 blood alcohol content (BAC), have an experienced driver in the passenger seat, not drive on any high-speed expressways, and not drive between the hours of midnight and 5 a.m. A G2 license is more similar to a G license, with fewer restrictions.

Method: This study analyzed data from the 2009 Ontario Student Drug Use and Health Survey (OSDUHS). The OSDUHS is a biennial population-based survey of students (grades 7 to 12) in Ontario, Canada.

Results: The results showed that 16.3% of licensed students in Ontario reported DUIC and 11.5% reported DUIA during the past year. After controlling for the effect of age, type of license emerged as a robust predictor for both DUIA and DUIC behavior, because students with a G2 and full license were significantly more likely to report DUIA and DUIC than drivers with a G1 license. Multivariate analyses suggested that risk-seeking behaviors were more important for understanding DUIA behavior than for DUIC behavior. Elevated problem indicators for alcohol and for cannabis were associated with DUIA and DUIC, respectively.

Conclusions: Though much attention has been paid to drinking and driving among adolescents, this research shows that more Ontario students now report driving after cannabis use than after drinking alcohol. The results identify important correlates of both behaviors that may be useful for prevention purposes.  相似文献   

123.
Decision making is of crucial importance in the lives of both animals and humans. How decisions of group members scale up to group decisions is of great interest. Accordingly, we gave homeless ant colonies (n = 67) in three experiments a choice between two nest sites (with small, big or mixed sand grains), each of which had to be excavated to be habitable. Among the colonies that chose only one of the new nest sites, all preferred the ones that could be excavated most easily and quickly. There are interesting parallels between the collective choice of mining sites and the ability of certain ants to select short cuts; both involve positive feedback. However, in this paper, we discuss a mechanism whereby collective co-ordination in the production of social infrastructure can occur in the absence of signalling.  相似文献   
124.
In behavior-based individual-based models (IBMs), demographic functions are emergent properties of the model and are not built into the model structure itself, as is the case with the more widely used demography-based IBMs. Our behavior-based IBM represents the physiology and behavioral decision making of individual animals and, from that, predicts how many survive the winter nonbreeding season, an important component of fitness. This paper provides the first test of such a model by predicting the change in winter mortality of a charadriid shorebird following removal of intertidal feeding habitat, the main effect of which was to increase bird density. After adjusting one calibration parameter to the level required to replicate the observed mortality rate before habitat loss, the model predicted that mortality would increase by 3.65%, which compares well with the observed increase of 3.17%. The implication that mortality was density-dependent was confirmed by predicting mortality over a range of bird densities. Further simulations showed that the density dependence was due to an increase in both interference and depletion competition as bird density increased. Other simulations suggested that an additional area of mudflat, equivalent to only 10% of the area that had been lost, would be needed by way of mitigation to return mortality to its original level. Being situated at a high shore level with the flow of water in and out impeded by inlet pipes, the mitigating mudflat would be accessible to birds when all mudflats in the estuary were covered at high tide, thus providing the birds with extra feeding time and not just a small replacement mudflat. Apart from providing the first, and confidence-raising, test of a behavior-based IBM, the results suggest (1) that the chosen calibration procedure was effective; (2) that where no new fieldwork is required, and despite being parameter rich, a behavior-based IBM can be parameterized quickly (few weeks), and thus cheaply, because so many of the parameter values can be obtained from the literature and are embedded in the model; and (3) that behavior-based IBMs can be used to explore system behavior (e.g., the role of depletion competition and interference competition in density-dependent mortality).  相似文献   
125.
Division of labour during colony emigration is widespread in ants. An important problem is how tasks are allocated during colony movement from one nest site to another. The generally favoured view is that emigrations are organised by a minority group of individuals, which either work unusually hard at tasks (elites) or have the exclusive task of carrying out the emigration (moving specialists). Five consecutive emigrations of a Leptothorax unifasciatus (Latr.) colony showed that the number of transporters, i.e. the individuals that took an active part in the emigration by transporting brood and ants, was smaller than it would have been if allocation of this task was random during each emigration. However, single emigrations of another three colonies, for which the spatial distribution and behaviour of the workers had been observed for a week prior to the emigration, demonstrated that the transporters did not form a homogeneous group. They differed in their spatial positions and tasks before the emigration. There was also no evidence that transporters worked harder or less hard than their nestmates before the emigration. Therefore, the individuals which carry out emigrations in L. unifasciatus colonies appear to be neither moving specialists nor elites. We propose that task allocation during emigrations of L. unifasciatus colonies is based on a feedback mechanism that involves learning.  相似文献   
126.
A scheme has been developed to rank 70 industrial organic chemicals in order of their priority for further study as potential contaminants of food. Numerical scales were developed for the following seven key criteria concerning environmental issues, food and toxicity:
  • -Production volume
  • -Pattern of usage
  • -Possible fate in the environment
  • -Likelihood of chemical entering the food chain
  • -Mechanism of entry into the food chain
  • -Persistence and accumulation in the food chain
  • -Toxicity.
  • Each chemical was assigned a score for the above criteria, which were combined to give an overall ranking for the chemicals. This scheme has been endorsed by the MAFF Steering Group on Chemical Aspects of Food Surveillance. It will be used in the assessment of relative priorities for further non-statutory surveillance for these contaminants in the UK food supply.  相似文献   
    127.
    The aqueous degradation of iodinated X-ray contrast media (ICM) by the combination of ozone and ultrasound has been studied. Experiments were conducted at a constant ultrasound frequency of 20 kHz, at five power densities up to 0.235 W/mL, and various ozone centrations. In experiments involving dissolved ozone in solution, the addition of ultrasound significantly decreased the oxidation performance of the dissolved ozone, while the combination of dissolved oxygen and ultrasound gave a greater oxidation performance than ultrasound alone. However, the combination of gaseous ozone and ultrasound was found to give a higher degree of compound degradation than either ozone or ultrasound alone. In the experiments with final effluent, the degradation of ICM compounds by gaseous ozone and ultrasound was found to depend on the ozone dose applied. The degradation of ICM compounds in final effluent was modeled, which was found to moderately overestimate the observed compound degradation.  相似文献   
    128.
    129.
    A survey of land taken out of production from the early 1990s onwards under the European Union's set-aside policy in England was carried out in 2008, to record plant communities in set-aside of different ages, effects of distance from the field edge, sowing and soil type. Communities were classified using the Countryside Vegetation System (CVS), Ellenberg indicators and Grime CSR strategy. Species richness declined with distance from the field boundary. Annuals declined with age of set-aside. In older set-aside, perennials dominated, 40-50% of species were grasses, and grasses covered over 70% of the area. Sown areas had a higher proportion of grass species and a lower proportion of wind-dispersed species. Perennial forbs increased over time in naturally regenerated swards but decreased on sown swards. Annuals and grasses were more prevalent on light soils, with more bare ground on heavy soils. Most transects fell into CVS aggregate classes ‘tall grassland/herb’ and ‘fertile grassland’. Ellenberg fertility values decreased initially but then stabilised. Competitor scores increased, and ruderal scores declined, with age. In general, the rate of change declined with age. Although few sites had plant communities of significant conservation interest, the value of set-aside is likely to be primarily to maintain botanical diversity in intensively farmed areas, as well as providing food and habitat for fauna.  相似文献   
    130.
    Agri-environment schemes (AES) are widely used policy instruments intended to combat widespread biodiversity declines across agricultural landscapes. Here, using a light trapping and mark-release-recapture study at a field-scale on nine common and widespread larger moth species, we investigate the effect of wide field margins (a popular current scheme option) and the presence of hedgerow trees (a potential scheme option in England) on moth abundance. Of these, we show that wide field margins positively affected abundances, although species did not all respond in the same way. We demonstrate that this variation can be attributed to species-specific mobility characteristics. Those species for which the effect of wide margins was strongest covered shorter distances, and were more frequently recaptured at their site of first capture. This demonstrates that the standard, field-scale uptake of AES may be effective only for less mobile species. We discuss that a landscape-scale approach, in contrast, could deliver significant biodiversity gains, as our results indicate that such an approach (perhaps delivered through targeting farmers to join AES) would be effective for the majority of wider countryside species, irrespective of their mobility level.  相似文献   
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