Sixteen-year-old drivers in fatal crashes, United States, 2003

OBJECTIVE: Key features of graduated licensing were introduced in 46 states and the District of Columbia between 1993 and 2003. State evaluations consistently have reported positive overall effects and positive effects of nighttime and passenger restrictions. Sixteen year-olds are the main target of graduated licensing, and the present study investigated changes in their fatal crash involvement and crash characteristics that have taken place nationally during 1993-2003. By looking at 16 year-olds nationally, the study does not constitute a direct test of the effect of graduated licensing laws per se. METHODS: Data on fatal crashes were obtained from the Fatality Analysis Reporting System. Sixteen year-olds were compared with older drivers. RESULTS: During these years, the extent to which 16-year-old drivers were in fatal crashes decreased substantially compared with older age groups. The drop in the per capita crash rate for 16 year-olds was 26%. The major change was a reduction in crashes involving transporting young passengers, especially in jurisdictions with restrictions that target these crashes. There was no change in the proportion of fatal late-night crashes even in states restricting this activity. CONCLUSIONS: There has been some progress nationally in reducing the crash problem for 16 year-olds, but this still is a big problem. To achieve further progress, the gaps and weaknesses in present graduated licensing laws will need to be addressed.     

The effect of iron on the biological activities of erionite and mordenite

Epidemiological data has demonstrated that environmental and/or occupational exposure to mineral particulates may result in the development of pulmonary fibrosis, bronchogenic carcinoma and malignant mesothelioma many years following exposure. It has been suggested that the genotoxic effects of fibrous particulates, such as asbestos, is due in part to the generation of reactive oxygen species (ROS) from iron associated with the particulates. However, the molecular mechanisms by which mineral particulates induce ROS that results in genotoxic damage remains unclear. The naturally occurring zeolites, erionite and mordenite share several physiochemical properties but they elicit very different biological responses, with erionite, a fibrous particulate, being highly toxic, and mordenite, a nonfibrous particulate, being relatively benign. We are using these natural zeolites as a model system to determine what physicochemical properties of these zeolites are responsible for their biological response(s) and to evaluate the parameters that influence these responses. The purpose of the present study was to determine the mutagenic potential of erionite and mordenite and to determine whether this mutagenic potential was modulated by iron. The results of this study using the Chinese hamster ovary cell line AS52 demonstrated that erionite was more cytotoxic than mordenite. However, the cytotoxicity of both zeolites was increased in the presence of physiological concentrations of ferrous chloride. Ferrous ions (5-20 microM) significantly (p<0.001) increased the cytotoxicity of mordenite, but only at the highest concentration (16 microg/cm(2)) of mordenite tested. Conversely, only the highest concentration (20 microM) of ferrous ion significantly (p<0.001) increased the cytotoxicity of erionite, but this enhanced cytotoxicity occurred over a wider concentration range (6-16 microg/cm(2)) of erionite. Mordenite was not mutagenic at any of the concentrations tested, and the mutagenic potential of mordenite was not enhanced by the addition of ferrous ion. Conversely, erionite was mutagenic in a dose-response manner at concentrations greater than 6 microg/cm(2) and the mutagenic potential of erionite was significantly enhanced by the addition of ferrous ions. These results suggest that while the cytotoxicity of mordenite and erionite may be related to the ability of these fibers to transport iron into a cell, the different coordination state of iron associated with the two fiber surfaces is critical for inducing genotoxic damage.     

Specific and long-term effects of Nova Scotia's graduated licensing program

A graduated licensing (GL) program was introduced in Nova Scotia, Canada, in October 1994. Previous research has shown that it reduced collisions in the short term. The present study examined the relative contribution of each stage of the program (i.e., learner and intermediate levels) and the program's impact after beginning drivers graduated to full licensure. The research focused on teenage beginning drivers (age 16-17), but the effects on older beginners also was examined. Per-driver crash rates of two groups of novices selected from driver records in Nova Scotia were compared. One group (pre-GL) received their learner's permits during the 2 years before the program was implemented, and the second group (GL) received their learner's permits during the 2 years after implementation. The findings clearly establish that most of the collision reduction in Nova Scotia's program occurred during the first year of the program, particularly during the first 6 months when the majority of novices were driving under supervision. The collision rate for 16 to 17-year-old GL novices was 50% lower than the rate for pre-GL novices during the 6 months after they received their learner's permits, and about 10% lower during their first 2 years of licensure when unsupervised driving from midnight to 5 A.M. was prohibited. Much of this improvement for 16 to 17-year-olds occurred during restricted night hours. Collision rates also were lower during nonrestricted hours in the initial 6 months of licensure. The 3-month "time discount" for driver education provided no safety benefit, and GL novices with driver education had collision rates that were not lower than pre-GL novices. There was no long-term effect found for the program after 16 to 17-year-olds graduated to full licensure. For older beginning drivers, crash rates during the first year after obtaining a learner's permit showed a 31% reduction. This effect diminished rapidly. There was only a 2% reduction during the first year of licensure, and crash rates increased during the following 2 years. Overall the data indicate substantial benefits of graduated licensing for 16 to 17-year-old beginners, but no benefits beyond the learner stage for older beginners.     

A Comparison of Richness Hotspots, Rarity Hotspots, and Complementary Areas for Conserving Diversity of British Birds

Biodiversity conservation requires efficient methods for choosing priority areas for in situ conservation management. We compared three quantitative methods for choosing 5% (an arbitrary figure) of all the 10 × 10 km grid cells in Britain to represent the diversity of breeding birds: (1) hotspots of richness, which selects the areas richest in species; (2) hotspots of range-size rarity (narrow endemism), which selects areas richest in those species with the most restricted ranges; and (3) sets of complementary areas, which selects areas with the greatest combined species richness. Our results show that richness hotspots contained the highest number of species-in-grid-cell records (with many representations of the more widespread species), whereas the method of complementary areas obtained the lowest number. However, whereas richness hotspots included representation of 89% of British species of breeding birds, and rarity hotspots included 98%, the areas chosen using complementarity represented all the species, where possible, at least six times over. The method of complementary areas was also well suited to supplementing the existing conservation network. For example, starting with grid cells with over 50% area cover by existing "Sites of Special Scientific Interest," we searched for a set of areas that could complete the representation of all the most threatened birds in Britain, the Red Data species. The method of complementary areas distinguishes between irreplaceable and flexible areas, which helps planners by providing alternatives for negotiation. This method can also show which particular species justify the choice of each area. Yet the complementary areas method will not be fully able to select the best areas for conservation management until we achieve integration of some of the more important factors affecting viability, threat, and cost.     

Characteristics and hazards of electrostatic discharges in air

In the assessment of electrostatic hazards in the process industries, a great deal of emphasis has been placed on the determination of energies in spark discharges. There are, however, other electrostatic discharge phenomena where this approach has severe limitations. The purpose of this paper is to describe the state-of-the-art with respect to electrostatic discharges in gases (air). An in depth review of the literature has been made, and the various types of discharges are tabulated and discussed.     

Book reviews

What Time is This Place?

Kevin Lynch

The MIT Press, Cambridge and London, England 1972, VIII and 277 pp, $5.95.

Planning and Profit in the Urban Economy

T. A. Broadbent (1977)

London: Methuen & Co.

"Sociology in Planning: a redefinition"

G. McDougall, J. Foulsham and J. Porter.

S.I.P. Paper No. 3, 1977, 27pp. Price 50p. Published by the organisation of Sociologists in Polytechnics and Cognate Institutions.

"Urban Freight Transport: problems and some possible solutions"

Alan R. Boyland

Working Papjer No. 26, Oxford Polytechnic Department of Town Planning.

A Critique of Urban Modelling

R. A. Sayer

Progress in Planning Series, edited by D. Diamond and J. B. McLoughlin, Volume 6, Part 3.

The Communications Factor in Office Decentralisation

J. B. Goddard and D. Morris

Progress in Planning Series edited by D. Diamond and J. M. McLoughlin, Vol. 6, Part 1.

Spatial Population Analysis

P. H. Rees and A. G. Wilson

Arnold, London, 1977. £27.50.

The Design Guidance Survey

Llewelyn‐Davies, Weeks, Forestier‐Walker and Bor. London 1976.     

Effects of feeding and starvation on proteolytic and tryptic activities in pyloric caecal tissues and duct fluids of the seastar Pisaster ochraceus

Pisaster ochraceus were collected at Post Point, Bellingham, Washington, USA, in 1980. Total protease and tryptic specific activities were measured in pyloric caecal tissues and pyloric duct fluids of fed and starved individuals. Feeding resulted in increased levels of total protease and tryptic activities, and led to an increase in the ratio of total protease to tryptic specific activity in pyloric caecal tissue and a decrease in that ratio in pyloric duct fluid, indicating a release of trypsin into the duct with feeding. Trypsin activity showed little variability in fed seastars, but was quite variable in starving individuals. Total proteolytic acitivity, unlike that of tryptic activity, was always present in both fed and starved seastars. This way indicate a much broader role of generalized proteases in the cells of the pyloric caecum (e.g. as lysosomal enzymes of absorptive cells) in comparison to tryptic enzymes.Please address all correspondence and requests for reprints to Dr. D. C. Williams at the Department of Biology     

Employee reactions to corporate social responsibility: an organizational justice framework

We seek to bridge the macro concept of corporate social responsibility (CSR) with micro research in organizational justice. A theoretical model is presented whereby employees' perceptions of CSR impact their subsequent emotions, attitudes, and behaviors, mediated by instrumental, relational, and deontic motives/needs, as well as moderated by organizations' social accounts. Copyright © 2006 John Wiley & Sons, Ltd.     

CHLOROPHYLL,PHOSPHORUS, SECCHI DISK,AND TROPHIC STATE1

ABSTRACT: The relationship between chlorophyll u, total phosphorus, secchi disk depth, and trophic state were examined using data on U.S. lakes collected by U.S. EPA's National Eutrophication Survey. By comparing predicted secchi disk depths with observed summer secchi disk depths in 757 lakes, it was determined that in many lakes non-chlorophyll related light attenuation is important in controlling the amount of chlorophyll u produced per unit of total phosphorus. Ranking of 44 lakes by 18 different trophic state measurements and single and multivariable indices were compared with rankings provided by mean summer ambient total phosphorus and chlorophyll u. The trophic state measurements and indices were much more successful in ranking the lakes against total phosphorus than chlorophyll u, indicating that there are differences in the relative trophic rankings of many of the lakes depending upon whether primary nutrients or biological manifestations are used as the ranking mechanism. If the manifestations of nutrients rather than their absolute levels are the primary criteria for beneficial use of lakes, the use of many of the commonly employed trophic state measurements, which assume or imply that there is a constant relationship between total phosphorus or secchi disk and chlorophyll, can lead to erroneous conclusions and unnecessary costly management controls. Secchi disk measurements may be more useful as a predictor of ambient lake total phosphorus concentrations than of chlorophyll.