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Graduated Driver Licensing (GDL) inserts between the leaner permit and full licensure an intermediate or "provisional" license that allows novices to drive unsupervised but subject to provisions intended to reduce the risks that accompany entry into highway traffic. Introduction of GDL has been followed by lowered accident rates, resulting from both limiting exposure of novices to unsafe situations and by helping them to deal with them more safely. Sources of safer driving include extended learning, early intervention, contingent advancement, and multistage instruction. To extend the learning process, most GDL systems lengthen the duration of the learner phase and require a specified level of adult-supervised driving. Results indicate that extended learning can reduce accidents substantially if well structured and highly controlled. Early intervention with novice traffic violators have shown both a general deterrent effect upon novice violators facing suspension and a specific effect upon those who have experienced it. Making advancement to full licensure contingent upon a violation-free record when driving on the provisional license has also evidenced a reduction in accidents and violations during that phase of licensure. Multistage instruction attempts development of advanced skills only after novices have had a chance to master more basic skills. Although this element of GDL has yet to be evaluated, research indicates crash reduction is possible in situations where it does not increase exposure to risk. While the various elements of GDL have demonstrated potential benefit in enhancing the safety of novice drivers, considerable improvement in the nature and enforcement of GDL requirements is needed to realize that potential.  相似文献   
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对环境监测布点采样中的QC/QA以及由采样引起的误差来源做了简要分析,并对监测采样过程中QC/QA的操作提出了一些设想。  相似文献   
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The study of the fetal platelet count and size can, according to the literature, be used for the prenatal diagnosis of the Wiskott-Aldrich syndrome (WAS). So far, no affected fetuses have been identified by this method. All pregnancies in which this method had been applied to resulted, as correctly predicted, in the birth of normal children. Here we report on a familial case of WAS where the haematological parameters failed to reveal the affected second child. Hence we assume that the platelet count and size of platelets remain normal in fetuses with WAS to the gestational age of 22 weeks and cannot be used for prenatal diagnosis.  相似文献   
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Objective: Studies of alcohol-related harm (violence, injury, illness) suggest that the most significant risk factors are the amount of alcohol consumed and whether obviously intoxicated patrons continue to be served. This study's objective was to investigate the effects of a responsible beverage service (RBS)/enhanced alcohol enforcement intervention on bars, bar patrons, and impaired driving.

Method: Two communities—Monroe County, New York, and Cleveland, Ohio—participated in a demonstration program and evaluation. The intervention applied RBS training, targeted enforcement, and corrective actions by law enforcement to a random sample of 10 identified problem bars in each community compared to 10 matched nonintervention problem bars. Data were collected over 3 waves on bar serving practices, bar patron intoxication, drinking and driving, and other alcohol-related harm from intervention and control bars and treatment and comparison communities.

Results: In Monroe County, New York, of the 14 outcome measures analyzed, 7 measures showed statistically significant differences from pre- to postintervention. Six of those measures indicated changes in the desired or positive direction and 2 measures were in the undesired or negative direction. Of note in the positive direction, the percentage of intervention bar patrons who were intoxicated decreased from 44 to 27% and the average blood alcohol concentration of patrons decreased from 0.097 to 0.059 g/dL pre- to postintervention. In Cleveland, Ohio, 6 of the 14 measures showed statistically significant changes pre- to postintervention with 6 in the positive direction and 4 in the negative direction. Of note, the percentage of pseudo-intoxicated patrons denied service in intervention bars increased from 6 to 29%.

Conclusions: Of the 14 outcome measures that were analyzed in each community, most indicated positive changes associated with the intervention, but others showed negative associations. About half of the measures showed no significance, the sample sizes were too small, or the data were unavailable. Therefore, at best, the results of these demonstration programs were mixed. There were, however, some positive indications from the intervention. It appears that when bar managers and owners are aware of the program and its enforcement and when servers are properly trained in RBS, fewer patrons may become intoxicated and greater efforts may be made to deny service to obviously intoxicated patrons. Given that about half of arrested impaired drivers had their last drink at a licensed establishment, widespread implementation of this strategy has the potential to help reduce impaired driving.  相似文献   

6.
Since the turn of the century, copper sulfate has been used extensively as an algicide to control nuisance algal blooms in drinking water reservoirs Recent experimental results have shown that the toxicity of copper to algae is determined by the activity of ionic copper, and not the total copper concentration The sensitivity of algae to ionic copper has been found to vary considerably for different algal species Chemical processes such as precipitation, complexation by dissolved organic substances, and adsorption by suspended material can be important in controlling the chemical speciation of copper added to drinking water reservoirs The copper sulfate dosage required for effective treatment of a reservoir is shown to depend on water chemistry and the copper sensitivity of nuisance algal species By evaluating copper chemistry and copper sensitivity of nuisance algal species it may be possible to obtain effective treatment with lower copper sulfate dosages in some reservoirs  相似文献   
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The U.S. Department of Defense (DoD) has been utilizing polymer matrix composite (PMC) and structural adhesive materials in military equipment for over 20 years. However, the volume of PMCs in fielded systems has remained relatively low. Currently, however, the DoD has established strategic goals that will necessitate the use of lightweight composites in order to meet performance requirements. Therefore, the volume of composites used in DoD systems is expected to see an unprecedented 100-fold increase over the next 30 years. As production volumes increase, the need to address environmental impact increases. The major contributions to environmental degradation from composites are generation of hazardous air pollutants (HAPs) and generation of hazardous (HW) and solid wastes. HAPs result primarily during the curing of the composite. HWs arise from expiration of stockpiled resin materials and from soiled support media used during manufacturing and clean up. Due to the wide range of applications and materials systems, as well as manufacturing and repair requirements, a family of environmentally benign solutions is needed to reduce and eliminate environmental impacts from PMC manufacturing. Solutions are proposed involving use of new technologies and materials to reduce pollutants from composite manufacturing. The technologies proposed include alternative curing of thermoset composites using electron beam (E-beam) irradiation and materials substitution employing thermoplastics processed using electromagnetic irradiation.  相似文献   
8.
Exposure studies have linked arsenic (As) ingestion with disease in mining-affected populations; however, inhalation of mine waste dust as a pathway for pulmonary toxicity and systemic absorption has received limited attention. A biologically relevant extractant was used to assess the 24-h lung bioaccessibility of As in dust isolated from four distinct types of historical gold mine wastes common to regional Victoria, Australia. Mine waste particles less than 20 µm in size (PM20) were incubated in a simulated lung fluid containing a major surface-active component found in mammalian lungs, dipalmitoylphosphatidylcholine. The supernatants were extracted, and their As contents measured after 1, 2, 4, 8 and 24 h. The resultant As solubility profiles show rapid dissolution followed by a more modest increasing trend, with between 75 and 82% of the total 24-h bioaccessible As released within the first 8 h. These profiles are consistent with the solubility profile of scorodite, a secondary As-bearing phase detected by X-ray diffraction in one of the investigated waste materials. Compared with similar studies, the cumulative As concentrations released at the 24-h time point were extremely low (range 297 ± 6–3983 ± 396 µg L?1), representing between 0.020 ± 0.002 and 0.036 ± 0.003% of the total As in the PM20.  相似文献   
9.
D epth to water, net Recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone, and Conductivity of the aquifer). Using such an approach allows one to investigate the potential for groundwater contamination on a regional, rather than site-specific, scale. Based upon data from variables such as soil permeability, depth to water, aquifer hydraulic conductivity, and topography, subjective numerical weightings have been assigned according to the variable's relative importance in regional groundwater quality. The weights for each variable comprise a GIS map layer. These map layers are combined to formulate the final groundwater pollution potential map. Using this method of investigation, the pollution potential map for the study area classifies 47% of the area as having low pollution potential, 26% as having moderate pollution potential, 22% as having high pollution potential, and 5% as having very high pollution potential.  相似文献   
10.
Recent research indicates that cell phone use can distract drivers from safe vehicle operation. However, estimates of the prevalence of cell phone use while driving have been limited to daytime hours and low-speed roadways. This paper describes the results of a study to estimate rates of cell phone use and other distractions by examining approximately 40,000 high-quality digital photographs of vehicles and drivers on the New Jersey Turnpike. The photographs, which originally were collected as part of a separate study, were taken both during the day and during the night and at different locations across the span of the Turnpike. A radar gun linked to the camera recorded the speeds of vehicles as they passed. This provided us with the speeds of every vehicle photographed, and allowed us to determine population counts of vehicles. A panel of three trained coders examined each photograph and recorded the presence of cell phone use by the drivers or any other distracting behavior. Demographic information on the driver was obtained during previous examinations of the photographs for an unrelated study. A rating was considered reliable when two out of the three coders agreed. Population estimates (and confidence intervals) of cell phone use and other distractions were estimated by weighting the cases by the inverse probability of vehicle selection. Logistic regression was used to predict cell phone use from demographic and situational factors. The results indicated that the most frequent distraction was cell phone use: 1.5% of the drivers on the Turnpike were using cell phones compared to the 3 to 4% use rates reported in the National Occupant Protection Use Survey (NOPUS) surveys conducted during the daytime on lower speed roadways. The Turnpike survey indicated that cell phones were used less on weekends and at night, and when the driver was exceeding the speed limit or had a passenger in the car.  相似文献   
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