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931.
932.
933.
This paper updates the comprehensive summary of graduated driver licensing (GDL) published in the January 2003 special issue of the Journal of Safety Research. It summarizes recent research not included in the special issue as well as research in progress or planned research. The most active research areas are risk factors for beginning teen drivers and evaluations of GDL programs. Results in each area strengthen the case for GDL. Additional research is producing valuable information about specific GDL implementation issues and the roles of parents and driver education in helping teenagers learn to drive safely. 相似文献
934.
PROBLEM: Most pedestrian fatalities occur at night. Although researchers have long understood that drivers have difficulty seeing pedestrians at night and that reflective clothing can dramatically enhance pedestrian conspicuity, the extent to which pedestrians understand these facts is unclear. This experiment quantified pedestrians' estimates of the ability of an approaching driver to recognize the presence of roadside pedestrians. METHOD: Ten younger and 10 older participants walked in place on the far shoulder of a closed-road circuit and pressed a button when they were confident that the approaching driver could first recognize that a pedestrian was present. RESULTS: Pedestrians overestimated their visibility and dramatically underestimated the benefit of conspicuity treatments. CONCLUSIONS: These results suggest that pedestrians fail to understand the magnitude of the nighttime conspicuity problem and the value of conspicuity treatments. Pedestrians may therefore unknowingly place themselves in danger at night. IMPACT: These results underscore the need to educate pedestrians about the dangers of interacting with traffic at night and about treatments that increase their safety. 相似文献
935.
Click It or Ticket is an occupant protection Selective Traffic Enforcement Program (sTEP) combining intensive paid and earned publicity with enforcement during a brief two to four week period. North Carolina demonstrated substantial increases in safety belt use associated with their implementation of the first statewide Click It or Ticket program in 1993. In 2000, Click It or Ticket was implemented in South Carolina. In 2001, Click It or Ticket was implemented across all eight states of the southeast. In 2002, ten states in various parts of the country implemented Click It or Ticket; four states implemented parts of the full Click It or Ticket program; and four states were used as comparisons. Belt use increases were greatest in the full implementation states. Click It or Ticket was implemented nationally in 2003. This paper presents a historical perspective on the implementation and evaluation of Click It or Ticket programs. 相似文献
936.
Wigand C McKinney RA Chintala MM Charpentier MA Groffman PM 《Journal of environmental quality》2004,33(3):1144-1151
Coastal salt marshes are a buffer between the uplands and adjacent coastal waters in New England (USA). With increasing N loads from developed watersheds, salt marshes could play an important role in the water quality maintenance of coastal waters. In this study we examined seasonal relationships between denitrification enzyme activity (DEA) in salt marshes of Narragansett Bay, Rhode Island, and watershed N loadings, land use, and terrestrial hydric soils. In a manipulative experiment, the effect of nutrient enrichment on DEA was examined in a saltmeadow cordgrass [Spartina patens (Aiton) Muhl.] marsh. In the high marsh, DEA significantly (p < 0.05) increased with watershed N loadings and decreased with the percent of hydric soils in a 200-m terrestrial buffer. In the low marsh, we found no significant relationships between DEA and watershed N loadings, residential land development, or terrestrial hydric soils. In the manipulation experiment, we measured increased DEA in N-amended treatments, but no effect in the P-amended treatments. The positive relationships between N loading and high marsh DEA support the hypothesis that salt marshes may be important buffers between the terrestrial landscape and estuaries, preventing the movement of land-derived N into coastal waters. The negative relationships between marsh DEA and the percent of hydric soils in the adjacent watershed illustrate the importance of natural buffers within the terrestrial landscape. Denitrification enzyme activity appears to be a useful index for comparing relative N exposure and the potential denitrification activity of coastal salt marshes. 相似文献
937.
The origin of faeces by means of biomarker detection 总被引:6,自引:0,他引:6
Bull ID Lockheart MJ Elhmmali MM Roberts DJ Evershed RP 《Environment international》2002,27(8):647-654
938.
Renate Matzke-Karasz David C. Horne Horst Janz Huw I. Griffiths William F. Hutchinson Richard C. Preece 《Die Naturwissenschaften》2001,88(6):268-272
Fossil spermatozoa are recorded for the first time in freshwater ostracods (small bivalved crustaceans) from Holocene sediments at sites in the United Kingdom and Germany. Exceptional conditions at these sites have resulted in the preservation of chitinous "soft parts", including limbs, the remains of Zenker's Organs (sperm pumps that are part of the male reproductive apparatus in cypridoidean ostracods) and spermatozoa from eight different species. Comparisons are made with spermatozoa from living ostracods and the implications of these discoveries for evolutionary studies of reproductive modes are discussed. 相似文献
939.
Brito JA McNeill FE Stronach I Webber CE Wells S Richard N Chettle DR 《Journal of environmental monitoring : JEM》2001,3(4):343-351
In this study, 539 occupationally exposed subjects received in vivo bone lead measurements using 109Cd excited K X-ray fluorescence (109Cd K XRF). Of these subjects, 327 had previously been measured five years earlier. Measurements were made from both tibia and calcaneus samples, taken to reflect cortical and trabecular bone, respectively. Changes in tibia lead concentration related negatively to initial tibia lead concentration and positively to both lead exposure between the measurement dates and initial calcaneus lead concentration. This finding confirmed and strengthened the interpretation of an earlier study involving fewer subjects. With the larger data set it was possible to examine subgroups of subjects. This showed that people aged less than 40 years had a shorter half-life for the release of lead from the tibia (4.9, 95% CI 3.6-7.8 years) than did those older than 40 (13.8, 95% CI 9.7-23.8 years). Similarly, less intensely exposed subjects (lifetime average blood lead < or = 25 micrograms dL-1) had a shorter tibia lead half-life (6.2, 95% CI 4.7-9.0 years) than those with a lifetime average blood lead > 25 micrograms dL-1 (14.7, 95% CI 9.7-29.9 years). Age and measures of lead exposure were strongly correlated; nevertheless, age matched subgroups with high and low intensity exposures showed clearance rates that were significantly different at the 10% level, with the lower exposure intensity again being associated with the faster clearance. These findings imply that current models of human lead metabolism should be examined with a view to adjusting them to account for kinetic rates varying with age and probably also with exposure level. 相似文献
940.
Richard Worrell Michael C. Appleby 《Journal of Agricultural and Environmental Ethics》2000,12(3):263-277
Stewardship is potentially a usefulconcept in modernizing management philosophies. Use ofthe term has increased markedly in recent years, yetthe term is used loosely and rarely defined in landmanagement literature. The connections between thispractical usage and the ethical basis of stewardshipare currently poorly developed. The followingdefinition is proposed: ``Stewardship is theresponsible use (including conservation) of naturalresources in a way that takes full and balancedaccount of the interests of society, futuregenerations, and other species, as well as of privateneeds, and accepts significant answerability tosociety.' A religious interpretation would require thephrase ``and ultimately to God' to be added.Stewardship has both secular and religiousinterpretations and it will be desirable to developboth of these aspects in parallel. A task forphilosophers is to establish whether the ethical basisof stewardship is sufficient to address environmentalconcerns or whether it is necessary to embrace widerethical approaches. Stewardship occupies similarground to several other concepts of use and managementof resources, particularly sustainability. It canbuild on sustainability by encouraging a broader viewof who and what should benefit from managementactivity. In particular, it focuses attention on therole of managers in providing public benefit and onenvisaging other species as a form of ``stakeholder' inmanagement decisions. Stewardship is applicable acrossthe widest range of fields of resource use and alsohas relevance to aspects of land tenure and propertyrights. Application of stewardship will require someadjustments in the roles of private managers/ownersvis-à-vis government. It might providemanagers with an expanded role and, importantly, amore positive image, both of themselves and in theeyes of the public. Stewardship could alsobe developed in a way that has relevance to citizensin general (as opposed to managers and owners ofresources), through their interactions with naturalresources as consumers. 相似文献