环境史的三个维度

历史学家间或会受到不重视理论的指责,环境史家未曾避免这种责难,有时理应如此.环境史家应当多多考察其学科的理论蕴涵,并鼓励多种观点之间更普遍的理性对话.本文并非提出一种理论结构,而是探讨会有助于设计此结构的三个维度.第一个维度关乎这一领域的主题,是文化-自然统一体.第二个维度与方法有关,将沿着历史和科学之间的统一体展开.第三个维度涉及范围,认为时间和空间在定义中相得益彰.显然还有其他可以探讨的维度.这里尝试性地进行这些思考,以期其只言片语可以在同行中开启兴味盎然的讨论.     

Group living decisions as youths transition to adulthood

This study follows teens through young adulthood as they transition to independent living. We focus on a little studied issue: why some youths live in groups rather than alone or with parents. This choice is important because the size of the group has a substantial impact on the demand for dwelling units; the more youths per dwelling the lower is aggregate demand and the greater is population density. Our study also adds to the knowledge of which factors influence youths' choice of destination as they leave the parental home. The empirical testing uses a discrete hazard model within a multinomial logit framework to allow for more than one possible state transition. We find that economic variables have little impact on the decision of whether to exit to a large versus a small group, while socio-demographic variables matter. We also test a new push-pull hypothesis and find that the pull of economic variables on the probability of exiting the parental home increases as youths reach their mid to late twenties. Received: 15 July 1999/Accepted: 15 May 2000     

Where the wild things are! Do urban green spaces with greater avian biodiversity promote more positive emotions in humans?

Urban Ecosystems - Urban green space can help mitigate the negative impacts of urban living and provide positive effects on citizens’ mood, health and well-being. Questions remain, however,...     

Can urban greening increase vector abundance in cities? The impact of mowing,local vegetation,and landscape composition on adult mosquito populations

Worldwide, cities are investing in greenspace to enhance urban quality of life and conserve biodiversity. Cities should ensure these investments do not unintentionally result in ecosystem disservices. Municipal management decisions regarding urban greenspaces, such as mowing frequency, could influence mosquito communities and public health. We examined how mowing, resultant vegetation characteristics, and landscape context influenced adult mosquito abundance in urban vacant lots. We sampled adult Culex and Aedes mosquitoes in a network of vacant lots within eight Cleveland, Ohio, USA neighborhoods in 2015 and 2016 using CO₂-baited light traps and grass-infused gravid traps. For each lot, we quantified vegetation characteristics, including plant diversity, bloom area, and biomass, as well as the surrounding landscape composition at radii of 60 and 1000 m. We found that periodic mowing did not significantly affect mosquito abundances. However, vacant lots with more diverse plant communities were associated with a greater light trap capture of both Culex and Aedes. Both mosquito genera declined in light trap catches with increased impervious surface at 60 m. Similarly, Culex (gravid trap) declined with the amount of built infrastructure at 1000 m. In contrast, Aedes (light trap) increased with the concentration of buildings in the landscape at 1000 m. Our findings indicate that reducing the frequency of mowing within vacant lots will not necessarily increase adult mosquito abundance. Nonetheless, mosquito surveillance and management should be considered when planning conservation-focused greenspaces, as vegetation design choices and the landscape context of a site do influence vector abundance and potentially disease risk.

     

An extended theory of planned behavior intervention for older adults with type 2 diabetes and cardiovascular disease

A randomized controlled trial evaluated the effectiveness of a 4-wk extended theory of planned behavior (TPB) intervention to promote regular physical activity and healthy eating among older adults diagnosed with Type 2 diabetes or cardiovascular disease (N = 183). Participants completed TPB measures of attitude, subjective norm, perceived behavioral control, and intention, as well as planning and behavior, at preintervention and 1 wk and 6 wk postintervention for each behavior. No significant time-by-condition effects emerged for healthy eating. For physical activity, significant time-by-condition effects were found for behavior, intention, planning, perceived behavioral control, and subjective norm. In particular, compared with control participants, the intervention group showed short-term improvements in physical activity and planning, with further analyses indicating that the effect of the intervention on behavior was mediated by planning. The results indicate that TPB-based interventions including planning strategies may encourage physical activity among older people with diabetes and cardiovascular disease.     

Problem gambling among female prisoners: lifetime prevalence,help-seeking behaviour and association with incarceration

The widespread introduction of electronic gaming machines (EGMs) in Australia has seen problem gambling (PG) rates soar over the past decade. This has been particularly apparent among women, with presentations to gambling help services increasing fivefold, and 90% of them indicating EGMs as the problem. Prisoners represent a group containing the highest PG rate found in any population. Despite a sharp increase in PG among women and the well-established link between offenders and PG, little data exists concerning PG among female prisoners. This study examined lifetime prevalence of PG among female prisoners in South Australia. The Early Intervention Gambling Health Test was administered to 74 female prisoners. Previous help-seeking behaviour and association with incarceration were also examined. Sixty-four percent of respondents indicated PG with one in six reporting they were incarcerated due to PG-related offending. Problem gamblers whose incarceration was related to PG were more likely to indicate they had gambled to try and win money to repay debts than problem gamblers incarcerated for unrelated offending. Given high levels of PG and overall low rates of help-seeking, women’s prisons may provide an opportunity to engage this high-risk population with effective treatment.     

How Prevalent Are Stable-Paretian Distributed Financial Variables?

Many studies have claimed that the stable-Paretian distribution should be used to model a wide variety of financial variables, ranging from stock and futures prices to exchange rates. Using a newly developed method, this study shows that the stable distribution is unsuitable for modeling most financial variables that are stable-distributed. We found that the distributions of a few accounting ratios may be stable. Our conclusions support a change in the future directions of financial-variable modeling.     

The age-varying effects of adolescent stress on impulsivity and sensation seeking

Adolescence is defined in part by heightened exposure and sensitivity to stressors. In a longitudinal cohort of youth at risk for substance use problems, we examined the age-varying relationship between stress exposure and traits that are central to the dual systems model. The positive associations between stress exposure, impulsivity, sensation seeking varied as function of age. Specifically, the influence of stress exposure on impulsivity strengthened during early adolescence and remained stable into early adulthood, while the influence of stress exposure on sensation seeking strengthened from early- to mid-adolescence and weakened thereafter. These findings suggest that the maturational imbalance between the capacity to regulate impulsive tendencies and sensation seeking may be exaggerated for youth who are exposed to a high number of stressors.