WalkSafe: a school-based pedestrian safety intervention program

OBJECTIVE: To evaluate the effectiveness of the WalkSafe program, an elementary school-based pedestrian safety program in a single high-risk district in Miami-Dade County. METHODS: Sixteen elementary schools were identified in a single high-risk district and enrolled in a one-year study. All schools implemented the WalkSafe program on the last week of January 2003. A pre, post, and three-month post testing of pedestrian safety knowledge was conducted. An observational component was also implemented at four schools that were randomly chosen. Engineering recommendations and law enforcement initiatives were also performed. RESULTS: A total of 6467 children from K-5th grade from 16 elementary schools participated in the program. Of these 5762 tests were collected over three different testing times. A significant difference (p-value < 0.001) was found between the pre and post testing conditions across all grade levels. There was no significant difference found between the post and three-month post testing conditions across all grade levels (p-value > 0.05). The observational data collected at four schools across the different testing times demonstrated a significant difference found between pre and post testing conditions for Group A (stop at the curb and look left, right, left) and also for Group B (midstreet crossing and darting out) (p-value < 0.05). There was no difference found between comparing the pre-test or post-test condition with the three-month post-test time. There were many environmental modifications that were recommended and actually performed. CONCLUSION: The WalkSafe program implemented in a single high-risk district was shown to improve the pedestrian safety knowledge of elementary school children. The observational data demonstrated improved crossing behaviors from pre-test to post-testing conditions. Future research will focus on sustaining the program in this district and expanding the program throughout our county.     

Effects of ultraviolet radiation and contaminant-related stressors on arctic freshwater ecosystems

Climate change is likely to act as a multiple stressor, leading to cumulative and/or synergistic impacts on aquatic systems. Projected increases in temperature and corresponding alterations in precipitation regimes will enhance contaminant influxes to aquatic systems, and independently increase the susceptibility of aquatic organisms to contaminant exposure and effects. The consequences for the biota will in most cases be additive (cumulative) and multiplicative (synergistic). The overall result will be higher contaminant loads and biomagnification in aquatic ecosystems. Changes in stratospheric ozone and corresponding ultraviolet radiation regimes are also expected to produce cumulative and/or synergistic effects on aquatic ecosystem structure and function. Reduced ice cover is likely to have a much greater effect on underwater UV radiation exposure than the projected levels of stratospheric ozone depletion. A major increase in UV radiation levels will cause enhanced damage to organisms (biomolecular, cellular, and physiological damage, and alterations in species composition). Allocations of energy and resources by aquatic biota to UV radiation protection will increase, probably decreasing trophic-level productivity. Elemental fluxes will increase via photochemical pathways.     

What determines the current presence or absence of permafrost in the Torneträsk region, a sub-arctic landscape in northern Sweden?

In a warming climate, permafrost is likely to be significantly reduced and eventually disappear from the sub-Arctic region. This will affect people at a range of scales, from locally by slumping of buildings and roads, to globally as melting of permafrost will most likely increase the emissions of the powerful greenhouse gas methane, which will further enhance global warming. In order to predict future changes in permafrost, it is crucial to understand what determines the presence or absence of permafrost under current climate conditions, to assess where permafrost is particularly vulnerable to climate change, and to identify where changes are already occurring. The Tornetr?sk region of northern sub-Arctic Sweden is one area where changes in permafrost have been recorded and where permafrost could be particularly vulnerable to any future climate changes. This paper therefore reviews the various physical, biological, and anthropogenic parameters that determine the presence or absence of permafrost in the Tornetr?sk region under current climate conditions, so that we can gain an understanding of its current vulnerability and potential future responses to climate change. A patchy permafrost distribution as found in the Tornetr?sk region is not random, but a consequence of site-specific factors that control the microclimate and hence the surface and subsurface temperature. It is also a product of past as well as current processes. In sub-Arctic areas such as northern Sweden, it is mainly the physical parameters, e.g., topography, soil type, and climate (in particular snow depth), that determine permafrost distribution. Even though humans have been present in the study area for centuries, their impacts on permafrost distribution can more or less be neglected at the catchment level. Because ongoing climate warming is projected to continue and lead to an increased snow cover, the permafrost in the region will most likely disappear within decades, at least at lower elevations.     

Gypsum Waste Disposal: Land vs Sea or Recycling

The disposal of waste gypsum wallboard at landfill sites in British Columbia (B.C.), Canada, resulted in the generation of hydrogen sulphide gas and toxic leachates. Although some remedial measures were taken to reduce or eliminate problems resulting from past dumping practices, many landfill operators refused to accept new waste for fear of litigation over the pollution of nearby streams and rivers. with the availability of legitimate disposal sites greatly reduced, a serious waste management problem arose. the two most promising options for reducing the accumulating waste appeared to be recycling and ocean disposal.

Agricultural use of the waste for soil conditioning would account for only a small portion of the waste generated annually. Manufacturing plants were reluctant to accept waste gypsum with a high paper fibre content for fear it would lower the quality of the new wallboard product or interfere with the existing equipment and processes in the plants. the technology for economically removing and separating the paper from the used or substandard wallboard had yet to be developed.

The environmental implications of disposal at sea were assessed by a government advisory committee under the provisions of the Canadian Environmental Protection Act. Although results of a test dump in internal waters of B.C. were positive, the committee felt that valuable amenities of nearshore waters would only be assured by restricting dumping to a remote offshore location. an acceptable disposal method with minimal impact on the marine environment was eventually found with appropriate pretreatment of the waste and the use of remotely controlled bottom dump scows. Recent progress in the processing of waste wallboard to make it acceptable to the manufacturing industry should significantly reduce if not eliminate the need to dispose of gypsum wallboard wastes at sea.     

Social support and occupational stress: Effects of talking to others

Employees' social support was examined using both the traditional global measures of emotional/instrumental support and more focused measures based on the contents (positive, negative, and non-job) of verbally transmitted support. Contents were more closely related to global emotional support than to global instrumental support, with non-job and positive communications especially strongly associated with emotional support, and they accounted for more variance in strains than did the global measures.     

Drinking to cope and self-medication: Characteristics of jobs in relation to workers' drinking behavior

This research extends recent studies of the relationship between characteristics of jobs and patterns of workers' alcohol consumption. Working within a ‘generalization perspective ’whereby job conditions are seen as having important effects on the mental health and behaviors of workers in non-work settings, the current research derives and tests a model of four job-related factors as they influence three aspects of alcohol use; the simple frequency—quantity of drinking, escapist-oriented reasons for drinking, and a combination of heavier drinking with escapist-oriented definitions which is labeled ‘self-medication’. Analyses of data drawn from the 1973 Quality of Employment Survey (QES) indicate that the relationship between jobs and drinking behavior is more complex than previously conceptualized. Specifically, we find evidence that for working men characteristics of jobs affect levels of alcohol consumption and the incidence of self-medicating drinking. These findings support and refine job-based explanations of drinking behavior. The implications of these findings for subsequent research and model-specification are discussed.     

Ambient ozone (O3) in three Class I wilderness areas in the northeastern USA: measurements with Ogawa passive samplers

Ambient ozone (O(3)) was measured in two Class I wilderness areas, one within the White Mountain National Forest in north central New Hampshire (NH) and one within the Green Mountain National Forest in southwestern Vermont (VT), for six weeks between 5 July and 16 August 1994, using Ogawa passive nitrite-coated filter samplers and a one week exposure period each time. Results for 7-day mean ambient O(3) concentrations from the passive samplers were compared to results from a co-located continuous ultraviolet photometric O(3) analyzer both in NH and VT. Although the size of the data set was small, agreement through simple linear regression between mean 7-day O(3) concentrations determined by the continuous monitors, and those obtained from the passive samplers was generally very good (adjusted R(2) = 0.759; p = 0.0003). Overall, excluding the one outlier value, any observed differences in the results obtained by the two methods when comparing co-located passive samplers to the continuous monitor within a given study location, appeared to be solely due to experimental error.     

气候变化与紫外线B辐射对北极苔原和极地荒漠生态系统的影响重要发现和扩展总结

引言 北极已成为对当前气候波动和预计的全球变暖增强的影响进行评估的重要地区.原因有以下几个方面:①在过去几十年中北极经历了大幅度的变暖过程(温度平均升高3℃,而在许多地区温度升高了4～5℃);②气候预测表明气候呈现持续变暖趋势,在2080年之前年平均气温升高4～5℃;③近期的气候变暖正在影响北极的环境和经济,这些影响还会加大,并对生活方式、文化及生态系统造成影响;④北极的变化可能会影响到地球上的其它地区.     

Possible use of constructed wetland to remove selenocyanate,arsenic, and boron from electric utility wastewater

Wetland microcosms were used to evaluate the ability of constructed wetlands to remove extremely high concentrations of selenocyanate (SeCN-), arsenic (As), and boron (B) from wastewater generated by a coal gasification plant in Indiana. The wetland microcosms significantly reduced the concentrations of selenium (Se), As, B, and cyanide (CN) in the wastewater by 64%, 47%, 31%, and 30%, respectively. In terms of the mass of each contaminant, 79%, 67%, 57%, and 54% of the Se, As, B, and CN, respectively, loaded into the microcosms were removed from the wastewater. The primary sink for the retention of contaminants within the microcosms was the sediment, which accounted for 63%, 51%, and 36% of the Se, As, and B, respectively. Accumulation in plant tissues accounted for only 2-4%, while 3% of the Se was removed by biological volatilization to the atmosphere. Of the 14 plant species tested, cattail, Thalia, and rabbitfoot grass were highly tolerant of the contaminants and exhibited no growth retardation. Environmental toxicity testing with fathead minnow (Pimephales promelas) larvae confirmed that the water treated by the wetland microcosms was less toxic than untreated water. The data from the wetland microcosms support the view that constructed wetlands could be used to successfully reduce the toxicity of aqueous effluent contaminated with extremely high concentrations of SeCN-, As, and B, and that a pilot-scale wetland should therefore be constructed to test this in the field. Cattail, Thalia, and rabbitfoot grass would be suitable plant species to establish in such wetlands.