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61.
There have been significant diversions of water from rivers and streams around the world; natural flow regimes have been perturbed by dams, barriers and excessive extractions. Many aspects of the ecological 'health' of riverine systems have declined due to changes in water flows, which has stimulated the development of thinking about the maintenance and restoration of these systems, which we refer to as environmental flow methodologies (EFMs). Most existing EFMs cannot deliver information on the population viability of species because they: (1) use habitat suitability as a proxy for population status; (2) use historical time series (usually of short duration) to forecast future conditions and flow sequences; (3) cannot, or do not, handle extreme flow events associated with climate variability; and (4) assume process stationarity for flow sequences, which means the past sequences are treated as good indicators of the future. These assumptions undermine the capacity of EFMs to properly represent risks associated with different flow management options; assumption (4) is untenable given most climate-change predictions. We discuss these concerns and advocate the use of demographic modelling as a more appropriate tool for linking population dynamics to flow regime change. A 'meta-species' approach to demographic modelling is discussed as a useful step from habitat based models towards modelling strategies grounded in ecological theory when limited data are available on flow-demographic relationships. Data requirements of demographic models will undoubtedly expose gaps in existing knowledge, but, in so doing, will strengthen future efforts to link changes in river flows with their ecological consequences.  相似文献   
62.
OBJECTIVES: To examine the frequency of underage drinking, driving after drinking and alcohol-related crashes, trends in these behaviors, and promising interventions. METHODS: We examined drinking and drinking- and-driving behaviors reported in the United States in the 2001 U.S. National Household Survey of Drug Abuse, the Centers for Disease Control and Prevention 2001 Youth Risk Behavior Survey, the 1992 National Longitudinal Alcohol Epidemiologic Study, and the 1999 National Survey of Drinking and Driving conducted for the National Highway Traffic Administration. We also examined the 1999 European School Survey Project on Alcohol and Other Drugs. Alcohol-related fatal crashes were examined from the U.S. Fatality Analysis Reporting System. Evaluation of interventions to reduce teenage drinking and driving after drinking were reviewed. RESULTS: In the United States, 19% of youth ages 12-20 consumed five or more drinks on an occasion in the past 30 days. Although European nations have lower legal drinking ages (16-18) than in the United States (21), similar proportions engage in underage drinking. In two-thirds of European countries, a greater percentage of 15-16 year-olds drank five or more drinks on an occasion in the past month than in the United States. In both the United States and Europe, the earlier people begin to drink, the greater the likelihood of developing alcohol dependence and other alcohol-related problems, including alcohol-related crash involvement, during adolescence and adult years. During the past 20 years alcohol-related traffic deaths among people younger than 21 have been cut in half in the United States, but progress has halted since 1995 and the problem is still large. Interventions shown by research to reduce alcohol-related crashes among youth include raising the legal drinking age to 21, zero tolerance laws, and some interventions that are family, school, or community based. CONCLUSIONS: Despite research showing that a variety of interventions can reduce underage drinking and alcohol-related crash fatalities, the frequency of these behaviors remains high and the average age of drinking initiation is declining in the United States. Efforts are needed to enhance publicized enforcement of underage drinking laws. Comprehensive community interventions that include enforcement of these laws also are needed.  相似文献   
63.
In situ remediation of aniline from soils and groundwater using biological and physical treatments was conducted at the BASF Corporation facility in Geismar, Louisiana. To mitigate the migration of aniline, remediate contaminated soil and groundwater, and determine concentrations, 24 immobilized microbe bioreactors were fixed in the subsoil, and a horizontal recovery well and 7 monitoring wells were installed. Soil and monitoring wells were sampled quarterly to assess bioplug impact on the aniline concentrations. The recovery well was sampled monthly to estimate the pounds of aniline removed from groundwater. Soil pH, composition, and microbial counts were used to estimate the fate and transport. Aniline levels were lowered significantly after remediation and total cancer risk was below levels for industrial sites, as established by State of Louisiana Risk Evaluation/Corrective Action Program guidelines. © 2010 Wiley Periodicals, Inc.  相似文献   
64.
    
The Town Scheme approach to urban conservation is being used increasingly as a major method of repairing historic buildings in conservation areas. A Town Scheme involves a long‐term financial and administrative partnership between the various levels of government. An annual budget made up of equal contributions from central government and the participating local authority is used to finance a multi‐year programme of repairs. Owners can apply for grants which are usually for 40 per cent of approved costs, and repair work must relate to the original structure and architectural details of an approved list of historic buildings. Town Schemes by themselves cannot totally transform the environmental quality of conservation areas, and the most successful schemes are part of wide‐ranging renewal and enhancement projects.  相似文献   
65.
Ultrasonographic and radiographic evaluation of a fetus at risk for osteogenesis imperfecta (O.I) type III was performed. Real-time ultrasound measurements at 15 weeks gestation were interpreted as normal, but at 20 and 22 weeks of gestation revealed marked shortening of the long bones and deformity of the femurs. The findings were confirmed by fetal radiography at 22 weeks gestation. Radiographic and histologic changes characteristic of O.I. were observed in the aborted fetus. Thus the antenatal manifestations of O.I. type III maybe severe enough to make prenatal diagnosis possible in the second trimester for families at risk for recurrence of this disorder.  相似文献   
66.
Recent molecular data on the maternally inherited mitochondrial (mt) DNA have challenged the traditional view that the now extinct Baltic sturgeon population belonged to the European sturgeon Acipenser sturio. Instead, there is evidence that American sea sturgeon Acipenser oxyrinchus historically immigrated into the Baltic Sea. In this study, we test the hypothesis that A. oxyrinchus introgressed into, rather than replaced, the A. sturio population in the Baltic. We established four single nucleotide polymorphisms (SNPs) in the nuclear MHC II antigen gene with a species-specific SNP pattern. Using an ancient DNA approach and two independent lines of molecular evidence (sequencing of allele-specific clones, SNaPshot), we detected both A. sturio and A. oxyrinchus alleles in the available museum material of the now extinct Baltic sturgeon population. The hybrid nature of the Baltic population was further confirmed by very high levels of heterozygosity. It had been previously postulated that the immigration of the cold-adapted A. oxyrinchus into the Baltic occurred during the Medieval Little Ice Age, when temperature likely dropped below the degree inducing spawning in A. sturio. Under this scenario, our new findings suggest that the genetic mosaic pattern in the Baltic sturgeon population (oxyrinchus mtDNA, sturio and oxyrinchus MHC alleles) is possibly caused by sex-biased introgression where spawning was largely restricted to immigrating American females, while fertilization was predominantly achieved by abundant local European males. The hybrid nature of the former Baltic sturgeon population should be taken into account in the current reintroduction measures. Electronic supplementary material  Supplementary material is available in the online version of this article at and is accessible for authorized users.  相似文献   
67.
68.
An apparent cancer cluster at a police detachment in a coastal British Columbia community was investigated. Police personnel suspected that the detachment building may have been a factor. Police personnel (20 current and 154 previous employees) associated with the detachment since 1963, the date of occupancy, were traced. After all 174 cases were contacted directly, or next of kin in case of death, a total of 16 cases of cancer or suspected cancers were reported. Of these 16, eight cases of cancer were confirmed through a cancer registry. Cancers included testicular, cervical, colon, skin (including melanoma), leukemias and lymphomas with an age range of diagnosis between 22 and 44 years. There was no evidence for an underlying event, factor or condition in the police building that could be attributed to the observed cancer cases. A possible association between these cancers and the use of police traffic radar is discussed.  相似文献   
69.
Changes towards environmental improvementsare becoming more politically acceptableglobally, especially in developedcountries. Society is slowly moving towardsseeking more sustainable productionmethods, waste minimisation, reduced airpollution from vehicles, distributed energygeneration, conservation of native forests,and reduction of greenhouse gas (GHG)emissions. Modern biomass, when used tosupply useful bioenergy services, has arole to play in each one of theseenvironmental drivers at both the large andsmall scales.This paper describes recent developments inbiomass supply and the technologies for itsconversion to bioenergy including biofuelsfor transport. It examines the economic,environmental and social benefits andidentifies barriers to bioenergy projectimplementation. Future opportunities forbiomass as a carbon (C) sink, a C offsetand a potential source of renewablehydrogen are discussed.Whether or not a bioenergy project iseconomically viable, as well as being trulyrenewable, sustainable and environmentallysound, is determined mainly by the sourceof biomass. The social benefits from usingbiomass are also valuable, though they areoften not clearly presented when proposingnew bioenergy projects or conductinganalyses of existing plants. Employmentrates per MWh or per GJ exceed those whenusing fossil fuel supplies to provide thesame energy service. `Ownership' bystakeholders and local communities at anearly stage in the development process isthe key to successful project developmentin order to share the benefits. Bioenergyhas a significant global role to play inthe mitigation of atmospheric GHG concentrations.  相似文献   
70.
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