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991.
Studies were carried out in two mining pond complexes in an industrial landscape. The first complex (consisting of six ponds) was located in an urban area and the second one (consisting of six ponds) in a woodland area. The aims of the study were to assess the diversity of benthic oligochaetes and to evaluate which environmental variables are most important in determining variations in the community structure in ponds of varying location. In total, 21 oligochaete species were recorded (7–11 in the urban ponds, 11–15 in the woodland ponds). Aulodrilus pluriseta, Aulodrilus japonicus and Ophidonais serpentina were only found in the woodland ponds, while Potamothrix bavaricus only occurred in the urban ponds. Limnodrilus hoffmeisteri, Limnodrilus claparedeanus, Chaetogaster diaphanus and Ophidonais serpentina dominated in the woodland ponds, whereas Limnodrilus hoffmeisteri, Limnodrilus claparedeanus, Potamothrix bavaricus and Tubifex tubifex prevailed in the urban ponds. The total density of oligochaetes was higher in the urban ponds thought the values of the diversity indices were higher in the woodland ponds. The local diversity of the ponds was high, while the among-site diversity made only a small contribution to the regional diversity. Nonetheless, a cluster analysis divided all of the ponds into two distinct groups depending on their location. CCA analysis showed that conductivity, pH, total hardness, alkalinity, the concentration of chlorides and the content of organic matter in the bottom sediments were most associated with the distribution of some oligochaete species among the ponds studied. 相似文献
992.
The environmental factors affecting the spatial dynamics of bird communities in urban parks are well understood, but much less attention has been paid to the seasonal dynamics of bird communities. Since migrant and resident human commensal birds might have contrasting responses to environmental factors of urban parks, we expected different seasonal dynamics among parks. On the other hand, because bird species can have different habitat relationships throughout the year, we also expected different responses of bird richness to environmental variables between breeding and non-breeding seasons. Bird surveys were conducted in 14 small urban parks (1–4 Ha) of Mar del Plata city (Argentina) for one full annual cycle. Bird richness changed between seasons, but bird abundance remained constant. Bird community composition did not vary between seasons, but urban parks near the urban center, with the highest pedestrian traffic and isolation to other green areas had the least seasonal change of composition. During the breeding season, bird richness was negatively affected by the percentage cover of high buildings surrounding the immediate limits of parks, whereas during the non-breeding season bird richness was not related with any environmental variable. Bird composition variation among parks was affected by the distance to the urban center during both seasons. Results showed that urbanization promotes a seasonal homogenization of bird communities in urban parks, probably by affecting the presence of migrant species and promoting the temporal stability of human commensal species. 相似文献
993.
Irga Peter J. Burchett Margaret D. O’Reilly Gabe Torpy Fraser R. 《Urban Ecosystems》2016,19(2):885-898
Urban Ecosystems - Many street trees in urban areas are deciduous and drop leaves during autumn. These leaves are a potential growing substrate for fungi, which when aerosolized and inhaled, can... 相似文献
994.
Peter Hart 《Journal of youth studies》2016,19(7):869-884
‘Professional boundaries’ set limits on appropriate behaviours in the relationship between the service users and practitioners. The professional literature often assumes boundaries are maintained by the practitioners, occupational bodies, or organisational policy. However in youth work this is under-researched. An ethnographic study of four youth clubs in the North East of England into ethical practice revealed that young people were surprisingly adept at maintaining boundaries with the youth workers. These boundaries were negotiated and maintained through the young people's use of space, their willingness to interact with the workers, the way they shared information with the workers, and their inclusion of youth workers into their social networking. Young people also showed a sophisticated awareness of the organisational boundaries youth workers were operating within, and often cooperated in maintaining them with the worker. The article concludes by arguing youth workers should take seriously young people's ability and willingness to set and work within boundaries, and see their negotiation and maintenance as a mutual endeavour. However, this may provide a challenge to organisations with rigid policy-defined boundaries. 相似文献
995.
Mehmet E. Yaya 《Review of Economics of the Household》2016,14(3):695-714
Until recently, in works of literature, the assimilation of immigrants had been viewed as an individualistic rather than a community-based process. However, Hatton and Leigh (2011) showed that immigrants integrate to their host country as communities, not as individuals; hence, group characteristics play as much of a role as individual characteristics in terms of adaptation. This paper introduces another dimension to the immigrant adaptation proxies that reflect community-based characteristics. The fundamental assertion of this paper is that inequality can be used as a proxy of adaptation within immigrant groups. Immigrant groups that exhibit income and education distributions similar to those of the natives can be regarded as well-adapted groups, while those who exhibit vastly different distributions should be considered to be groups with limited adaptation. Using the American Community Survey (ACS) 2010 cohort, this paper presents the initial findings of the within-group inequality of immigrants. Then, a cross-sectional regression analysis is employed to analyze the determinants of inequality across these immigrant groups. The results suggest that immigrant community-based characteristics, such as average income, education, and number of years that the immigrants have spent in the US, can indeed explain most of the variation in inequality. 相似文献
996.
This paper describes and analyzes research on the dynamics of long-term care and the policy relevance of identifying the sources of persistence in caregiving arrangements (including the effect of dynamics on parameter estimates, implications for family welfare, parent welfare, child welfare, and cost of government programs). We discuss sources and causes of observed persistence in caregiving arrangements including inertia/state dependence (confounded by unobserved heterogeneity) and costs of changing caregivers. We comment on causes of dynamics including learning/human capital accumulation; burnout; and game-playing. We suggest how to deal with endogenous geography; dynamics in discrete and continuous choices; and equilibrium issues (multiple equilibria, dynamic equilibria). We also present an overview of commonly used longitudinal data sets and evaluate their relative advantages/disadvantages. We also discuss other data issues related to noisy measures of wealth and family structure. Finally, we suggest some methods to handle econometric problems such as endogeneous geography. 相似文献
997.
Andres J. Vargas 《Review of Economics of the Household》2016,14(3):625-668
I use the American Time Use Survey from 2003 to 2012 to analyze, from a gender and marital status perspective, how the time Mexican immigrants devote to market work, household production, personal care, and leisure activities compare to the corresponding time allocations of US natives. Furthermore, I estimate the effect of duration of residence in the US on the immigrants overall patterns of time use. Time diary evidence indicates that, upon arrival to the US, Mexican immigrant men devote more time to market work and commuting than comparable non-Hispanic natives, regardless of their marital status. On the other hand, Mexican immigrant women devote the same amount of time to these activities as the non-Hispanic reference groups, irrespective of the marital status. In addition, the trend data show that immigrant men decrease their paid work with years since migration while immigrant women increase it. Estimates indicate that, for married immigrant men there is a tradeoff between market work and household work, whereas for single immigrant men the tradeoff is between market work and leisure. Finally, Mexican immigrant women relinquish mostly passive leisure and sleep time to meet demands of family and market work. 相似文献
998.
Previous research suggests that parents may be less happy than non-parents. We critically assess the literature and examine parents’ and non-parents’ happiness-trends using the General Social Survey (N = 42,298) and DDB Lifestyle Survey (N = 75,237). We find that parents are becoming happier over time relative to non-parents, that non-parents’ happiness is declining absolutely, and that estimates of the parental happiness gap are sensitive to the time-period analyzed. These results are consistent across two datasets, most subgroups, and various specifications. Finally, we present evidence that suggests children appear to protect parents against social and economic forces that may be reducing happiness among non-parents. 相似文献
999.
A global count of the extreme poor in 2012: data issues,methodology and initial results 总被引:1,自引:0,他引:1
Francisco H. G. Ferreira Shaohua Chen Andrew Dabalen Yuri Dikhanov Nada Hamadeh Dean Jolliffe Ambar Narayan Espen Beer Prydz Ana Revenga Prem Sangraula Umar Serajuddin Nobuo Yoshida 《Journal of Economic Inequality》2016,14(2):141-172
The 2014 release of a new set of purchasing power parity (PPP) conversion factors (PPPs) for 2011 has prompted a revision of the World Bank’s international poverty line. In revising the line, we have sought to minimize changes to the real purchasing power of the earlier $1.25 line (in 2005 PPPs), so as to preserve the integrity of the goalposts for international targets such as the Sustainable Development Goals (SDGs) and the World Bank’s twin goals – which were set with respect to that line. In particular, the new line was obtained by inflating the same fifteen national poverty lines – originally used by Ravallion et al. (World Bank Econ. Rev. 23(2): 163–184 2009) to construct the $1.25 line – to 2011 prices in local currency units, and then converting them to US dollars using 2011 PPP conversion factors. With a small approximation, this procedure yields a new international poverty line of $1.90 per person per day. In combination with other changes described in the paper, this revision leads to relatively small changes in global poverty incidence for 2011: from 14.5 % using the old method to 14.1 % using the new method. In 2012, the new reference year for the global count, we find 12.7 % of the world’s population, or 897 million people, are living in extreme poverty. There are changes in the regional composition of poverty, but they are also relatively small. This paper documents methodological decisions taken in the process of updating both the poverty line and the consumption and income distributions at the country level, including issues of inter-temporal and spatial price adjustments. It also describes various caveats and limitations of the approach taken. 相似文献
1000.
Prenatal Reflective Functioning and Accumulated Risk as Predictors of Maternal Interactive Behavior During Free Play,the Still‐Face Paradigm,and Two Teaching Tasks 下载免费PDF全文
Hanneke J. A. Smaling Stephan C. J. Huijbregts Jill Suurland Kristiaan B. van der Heijden Judi Mesman Stephanie H. M. van Goozen Hanna Swaab 《Infancy》2016,21(6):766-784
This study examined whether prenatal reflective functioning (RF) was related to mothers’ interactive style across contexts with their 6‐month‐old infants (M age = 6.02 months, SD = 0.41, 54% boys), and to what extent quality of prenatal RF could account for the influence of accumulated risk on maternal interactive behavior. Accumulated risk was defined as the sum‐score of a selection of risk factors that have been associated with suboptimal infant development. Mother–infant dyads (N = 133) were observed during free play, two teaching tasks, and the Still‐Face Paradigm (SFP). Better prenatal RF was associated with more positive maternal behavior in all settings and less negative behavior during teaching and SFP reengagement. Accumulated risk and prenatal RF predicted shared variance in maternal interactive behavior (with unique predictive effects observed only for RF on sensitivity during teaching and SFP play, and for accumulated risk on sensitivity and positive engagement during SFP play, and internalizing‐helplessness during SFP reengagement). Accumulated risk had an indirect effect on maternal sensitivity during teaching and SFP play through prenatal RF. These findings suggest not only that RF may be targeted prenatally to improve mother–infant interactions, but also that enhancing RF skills may ameliorate some of the negative consequences from more stable perinatal risk factors that influence parent–child interactions. 相似文献