996 resultados para change in costs


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Organisms provide some of the most sensitive indicators of climate change and evolutionary responses are becoming apparent in species with short generation times. Large datasets on genetic polymorphism that can provide an historical benchmark against which to test for recent evolutionary responses are very rare, but an exception is found in the brown-lipped banded snail (Cepaea nemoralis). This species is sensitive to its thermal environment and exhibits several polymorphisms of shell colour and banding pattern affecting shell albedo in the majority of populations within its native range in Europe. We tested for evolutionary changes in shell albedo that might have been driven by the warming of the climate in Europe over the last half century by compiling an historical dataset for 6,515 native populations of C. nemoralis and comparing this with new data on nearly 3,000 populations. The new data were sampled mainly in 2009 through the Evolution MegaLab, a citizen science project that engaged thousands of volunteers in 15 countries throughout Europe in the biggest such exercise ever undertaken. A known geographic cline in the frequency of the colour phenotype with the highest albedo (yellow) was shown to have persisted and a difference in colour frequency between woodland and more open habitats was confirmed, but there was no general increase in the frequency of yellow shells. This may have been because snails adapted to a warming climate through behavioural thermoregulation. By contrast, we detected an unexpected decrease in the frequency of Unbanded shells and an increase in the Mid-banded morph. Neither of these evolutionary changes appears to be a direct response to climate change, indicating that the influence of other selective agents, possibly related to changing predation pressure and habitat change with effects on micro-climate.

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Drive for thinness (DT) and social body comparison (SBC) have been highly correlated with body dissatisfaction, a robust risk factor for eating disorders; however, there is little understanding of how these two variables relate to increases in body dissatisfaction over time. In the present study, I investigated how high initial levels of DT and SBC correlate with changes in body dissatisfaction and ideal body by surveying 110 first-year women at the beginning and end of their first semester. There was no significant relationship between high initial DT and SBC and changes in either body dissatisfaction or ideal body. However, high initial SBC was almost significantly correlated with change in ideal body due to women with low SBC choosing larger bodies at follow-up. In addition, women with high initial DT and SBC had higher body dissatisfaction than women with low initial levels of both variables. Women with high initial SBC chose thinner ideal bodies than women with low initial SBC. Lastly, change in body dissatisfaction was negatively correlated with change in ideal body. If replicated, I would hope these findings could contribute to a better understanding of how women’s perception of their bodies changes over the course of their first semester in college and inform interventions to address this potential risk factor for disordered eating.

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The expansion of agriculture in the Near East during the middle Holocene significantly altered the physical landscape. However, the relationship between the scale of agriculture and the magnitude and timing of the environmental impacts is not well known. The Gordion Regional Survey provides a novel dataset to compare settlement density during archaeological periods to rates of environmental disruption. Sediment samples from alluvial cores directly date the environmental disruption, which can be matched to period-specific settlement intensities in the watershed as constructed from archaeological survey ceramics. Degradation rates rose sharply within a millennium of the earliest Chalcolithic occupation. Early Bronze Age (EBA) land use induced the greatest rates of environmental degradation, although settlement density was relatively low on the landscape. The degradation rate subsequently decreased to one-third its early peak by the Iron Age, even as settlement intensity climbed. This trajectory reveals how complex interaction effects can amplify or subdue the responses of the landscape-land use system. Prior to settlement, landscape soil reservoirs were highly vulnerable, easily tipped by early agricultural expansion. Subsequent reduced rates of erosion are tied both to changes in sociopolitical organization and to depletion of the vulnerable soil supply.

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The reconstruction of the child protection system in the post-communist period so as to meet professional standards while responding to the needs of children is an enormous task. In order to understand the features of the current stage of the development of the Romanian child protection system and to evaluate its trends towards change, Roth-Szamoskozi analysed data from scientific literature and collected statistics to document the evolution of the child-protection structure. Empirical data collection using qualitative methods (content analysis of documents and interviews with staff) were designed to reflect the degree to which child welfare laws correspond to internationally accepted regulations and to analyse the attitudes of those working in the field at different decision-making levels. An experiment with a group of 12 students showed that there have been basic changes in the legal framework of Romanian child welfare. Students could see that the required principles exist in the new Romanian child protection law, but also identified areas which are still inadequately represented. 61 staff members working in child welfare agencies (both state and non-governmental) were also interviewed, using a systematic, circular interview. Using the criteria of competence and the existence of specific social goals, professionalism in solving social problems and respect for social-work values, the 30 non-governmental organisations were divided into three categories. The first (7 organisations) are active in the area, know the law and are fairly professional, the second (5) are motivated in their work with specific problems, but with no great competence. The 18 organisations in the third group have no competence in the social field and in issues concerning children and do only charitable work. The state agencies are still dominated by routine, but there were many staff members who were developing reform and strategic roles and were actively directing the system towards change. Many staff members in both governmental and non-governmental organisations were directing the system towards a stress on intervention in the interests of the child in the context of its family. Roth-Szamoskozi found that staff members felt the need of a more accurate evaluation system which would enable them to show their results more clearly.