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201.
Urbanisation is widely considered to promote the establishment of non-native species, but there is limited empirical evidence of the ecological factors driving their responses. The grey squirrel Sciurus carolinensis (Gmelin 1788) is native to North America, but is widespread in the UK and is starting to spread across Europe. It is regarded as one of the world’s worst invasive animals due to its adverse impacts on native biodiversity. We use the non-native grey squirrel population in Sheffield (UK) as a case study to assess which factors limit its distribution and abundance in urban environments. In 2010 the city-wide population of adult squirrels peaked at an estimated 6539 in autumn (0.46 squirrels/ha), with maximum local densities of 8.29/ha. These densities appear to be slightly lower than those recorded in urban environments in the species’ native range. Grey squirrels occurred more frequently at urban sites with larger amounts of green-space in the surrounding region. Local habitat characteristics were, however, more powerful predictors of urban grey squirrel occurrence and abundance than regional availability of green space. Canopy cover, seed bearing trees and supplementary feeders, provided for garden birds, positively influenced grey squirrels. The potential for grey squirrels to connect city dwellers with nature thus appears to be highest in urban locations that have considerable capacity to support native biodiversity. The beneficial impacts of supplementary feeding on grey squirrel populations is notable given concerns that squirrels can adversely influence bird populations. These habitat associations also imply that grey squirrels typically respond negatively to urbanisation, which challenges arguments that urbanisation favours exotic species. 相似文献
202.
203.
Mark A. Hager Ph.D. 《Nonprofit management & leadership》2018,28(3):291-294
204.
This paper asserts that levels of knowledge about practice teaching are low. It briefly reviews three areas; ideologies and paradigms of practice teaching, development of new structural arrangements and the processes of teaching and learning as experienced by students and practice teachers. An agenda for future inquiry is suggested. 相似文献
205.
Risk Homeostasis Theory and Traffic Accident Data 总被引:3,自引:0,他引:3
Leonard Evans 《Risk analysis》1986,6(1):81-94
The risk homeostasis theory posits, in essence, that a control mechanism analogous to the thermal homeostatic system in warm-blooded animals tends to keep risk per unit time constant, and, as a consequence, the number of traffic accidents per unit time of driving also tends to remain constant, essentially independent of changes in the traffic safety system. It is the purpose of the present research to examine the validity of this claim using a wide variety of traffic accident data. All the data examined are found to be incompatible with the risk homeostasis theory. The only specific field accident data offered in the literature to support the risk homeostasis theory are found to, in fact, refute the theory. The accident data provide evidence that a rich variety of user responses occur. While it is possible for users to collectively respond in such a way that safety benefits are completely cancelled, such a response is not particularly common; it is certainly not universally occurring, as suggested by the risk homeostasis theory. It is concluded that the risk homeostasis theory should be rejected because there is no convincing evidence supporting it and much evidence refuting it. 相似文献
206.
1. Development is an essential lifelong process if we are to compassionately care for patients in forensic and correctional nursing. 2. Many of us are blocked in our ability to understand and to care; we will need to grow to meet the challenges and to bear the shocks of forensic and correctional nursing. 3. Concepts that correspond to Kegan's levels of consciousness imply a progression from punitive attitudes toward more positive attitudes. 相似文献
207.
Very few demographic surveys in developing countries have gathered information on household incomes or consumption expenditures. Researchers interested in living standards therefore have had little alternative but to rely on simple proxy indicators. The properties of these proxies have not been analyzed systematically. We ask what hypotheses can be tested using proxies, and compare these indicators with consumption expenditures per adult, our preferred measure of living standards. We find that the proxies employed in much demographic research are very weak predictors of consumption per adult. Nevertheless, hypothesis tests based on proxies are likely to be powerful enough to warrant consideration. 相似文献
208.
Griffiths M Scarfe A Bellringer P 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》1999,15(1):83-90
This study outlines the results of the UK's national gambling helpline run by GamCare. The results outlined here cover the period of the first 12 months of operation (November 1997 to October 1998). The helpline received a total of 1729 calls. Of these, 51% were from problem gamblers themselves (90% male; 10% female) and a further 26% of calls were from relatives of problem gamblers. The remaining calls came from other professionals handling problem gambling cases (13%), attempted calls, e.g., people calling and then putting the phone down due to being scared of talking (4%), information requests (3%) and the media (3%). Fruit machine gambling appeared to be most problematic for the callers as a whole and for particular sub-groups such as adolescents (82%) and women (52%). 相似文献
209.
Is a shorter life with more years lived in poor health a defining attribute of the life cycle of disadvantaged groups? Based on the J990 5% Public Use Microdata Survey, we develop life table models of healthy (or active) life for the major racial groups, by sex, in the United States. The analysis underscores the complexity of the relationship between morbidity and mortality in the population. For Asians, longer life is associated with fewer years lived in poor health. In contrast, Native Americans’ relatively longer lives are accompanied by extended periods of chronic health problems. of all racial groups, blacks live the fewest years, and they live a high proportion of those years with a chronic health problem. Hispanics also live substantially fewer years, yet the period of life they spend with a health problem is relatively compressed. Racial differences in the link between morbidity and mortality point to the importance of investigating how chronic diseases and disease prevention and treatment are related to active life across the population subgroups. 相似文献
210.
Baron E Dickerson M 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》1999,15(1):3-15
This paper reports the results of a preliminary investigation into whether the drinking of alcohol contributes to impaired control of gambling behaviour. The sampling method consisted of a two-phase survey design, collecting data both prospectively within session and retrospectively via a take-home questionnaire. One hundred sixteen people were interviewed while in a gaming venue playing on an electronic gaming machine (egm) of whom 34 men and 11 women also returned take-home surveys. Comparisons of the sample to previous studies suggested that the sample was representative of the population of egm players. Results indicated a consistent theme of alcohol use contributing significantly to impaired control of gambling behaviour, with level of involvement (Corless & Dickerson, 1989) contributing the most significant variance in the independent variables. Limitations of the study are discussed, but the case is argued that this type of process research is essential in better understanding how these two types of popular leisure activities may interact, possibly leading to the previously recorded chronic, excessive alcohol intake and problematic gambling (e.g. McCormick, Russo, Ramirez & Taber, 1984). 相似文献