PM2.5 assessment in 21 European study centers of ECRHS II: Method and first winter results

The follow-up of a cohort of adults from 29 European centers of the former European Community Respiratory Health Survey (ECRHS) I (1989-1992) will examine the long-term effects of exposure to ambient air pollution on the incidence, course, and prognosis of respiratory diseases, in particular asthma and decline in lung function. The purpose of this article is to describe the methodology and the European-wide quality control program for the collection of particles with 50% cut-off size of 2.5 microm aerodynamic diameter (PM2.5) in the ECRHS II and to present the PM2.5 results from the winter period 2000-2001. Because PM2.5 is not routinely monitored in Europe, we measured PM2.5 mass concentrations in 21 participating centers to estimate background exposure in these cities. A standardized protocol was developed using identical equipment in each center (U.S. Environmental Protection Agency Well Impactor Ninety-Six [WINS] and PQ167 from BGI, Inc.). Filters were weighed in a single central laboratory. Sampling was conducted for 7 days per month for a year. Winter mean PM2.5 mass concentrations (November 2000-February 2001) varied substantially, with Iceland reporting the lowest value (5 microg/m3) and northern Italy the highest (69 microg/m3). A standardized procedure appropriate for PM2.5 exposure assessment in a multicenter study was developed. We expect ECRHS II to have sufficient variation in exposure to assess long-term effects of air pollution in this cohort. Any bias caused by variation in the characteristics of the chosen monitoring location (e.g., proximity to traffic sources) will be addressed in later analyses. Given the homogenous spatial distribution of PM2.5, however, concentrations measured near traffic are not expected to differ substantially from those measured at urban background sites.     

RESEARCH: Triage Law Enforcement: Societal Impacts on National Forests in the West

/ Uses of outdoor natural areas, like National Forests in the United States, have been undergoing change. Some changes, including criminal activities and domestic terrorism, may have quite important impacts to outdoor enthusiasts and managers. Activities include some relatively traditional management challenges, like arson and thefts, and newer challenges, such as domestic violence and murder. To better understand the prevalence and impacts of these activities, selected managers in the western United States were interviewed in summer and fall 1998. Results indicate criminal activities and domestic terrorism are found in both urban-interface and rural sites. The most prevalent challenges were arson, criminal damage, domestic violence, dumping of household trash and landscape materials, marijuana cultivation, satanic cult activity, and thefts. Not as prevalent but found in almost all study sites were body dumping, extremist group activity, gang activity, murders, and suicides. Managers felt that most outdoor recreationists were unaffected by the activities. Most managers noted the increasing prevalence and the costs to management in time, personnel, and in other ways. They noted that their job had ceased being one of natural resources law enforcement and became one of "city" law enforcement. The findings of the study raise serious issues that require additional research.     

Positive Planning for Wind-Turbines in an Urban Context

An international concern with climate change has prompted a political commitment to the use of renewable energies. Yet, the operationalization and management of this political objective may be frustrated at the local level, where, it is suggested, an implementation impasse exists. This paper reports on a case study that examines the planning issues around the harvesting of wind at an urban brownfield site in Scotland. The paper discusses the nature of the state-market-civil relations involved in the development management of private wind-energy infrastructure, and the potential for a positive mediating role for the planning system.     

一种改进的多学习教与学优化算法

针对传统教与学算法在解决复杂多峰函数优化问题时,具有局部最优且搜索开发能力较差的缺点,提出了一种改进的多学习教与学优化算法,新算法为学员的每一维加入不同的教学因子,设计了基于学员均值比较的教师选择策略和向教师及学员学习的多学习策略。基于多个单峰和多峰函数的仿真结果表明,新算法跟传统的、改进的教与学算法相比,在稳定性、寻优精度和收敛速度方面更具优势。