Safety regulators in the railroad industry need comprehensive injury costs by cause, and cost comparisons to other modes of transport to gain policy insights. This study links case-level data from the Federal Railroad Administration to monetary costs and consequences of specific injuries. Lost quality of life was estimated from physicians' ratings of injury impairment and the value of fatal risk reduction. Railroad injuries and illnesses cause an average of $3 billion in fatality costs and $650 million in nonfatal incident costs annually. Impacts at rail-highway crossings impose three times as much cost as the next highest cause. Commercial air travel is the safest per passenger mile. Trains, second lowest, have injury costs six times higher, but only one-fifth as high as cars. The relative safety of trains and airplanes in transport means highway modes enjoy implicit price subsidies. Better injury cost recovery through taxation or insurance would make the subsidies explicit. More informed modal choices and thus enhanced economic efficiency would result. 相似文献
ABSTRACT: The Lower Fox River, Wisconsin, hosts the densest concentration of paper mills in the US., with 18 located along a 4Gde stretch between Lake Winnebago and Green Bay, Lake Michigan. Some of these companies use only primary, others also secondary, waste treatment techniques. Comparison of the quantities of wastes discharged with the legal limits indicates that all plants discharge only 40-50 percent or less of the allowable suspended solids; most discharge < 50 percent of the allowable BOD. This is equal or better than the performance of paper companies elsewhere in the state. Reductions in pollutant discharges have corresponded to improved water quality, though too much BOD is still discharged to be adequately assimilated by the Fox River. The relatively low current level of discharges means permit levels would have to be drastically cut to make any significant impact on water quality. Only a few companies might be seriously affected by such changes. Flow and temperature related permits would likely be more effective, but more difficult to comply with for the industry. Toxic substances are also a potential problem, particularly chlororganic compounds that can form in situ from the chlorine frequently used for pulp bleaching. 相似文献
Objective: This study was designed to investigate the 15-year impact of Georgia's graduated drivers' licensing (GDL) law, the “Teenage and Adult Driver Responsibility Act” (TADRA), on fatality crashes among young drivers.
Methods: Fatality Analysis Reporting System (FARS) data for Georgia and Census denominators were used to determine fatal crash rates (FCRs) of drivers ages 16 through 19 who passed through the Georgia GDL system during the 5.5 years prior to through 15.5 years after TADRA's implementation. FCRs of younger drivers were compared to those of drivers ages 20–54 and 55–75 and compared by gender. Attention was given to speeding- and alcohol-related crashes, 2 foci of TADRA.
Results: The decline in FCRs has been maintained and even increased through 15.5 years after passage of the law. Extending the curfew and further limiting passengers (passed in 2001) and driver's education and supervised driving requirements (added in 2007) may have contributed. The greatest declines were among 16- and 17-year-olds; most of the gains were among male drivers. The changes were greatest for alcohol- and speeding-related crashes. Those 18 and 19 years old did not demonstrate an increase in FCR over the period studied.
Conclusion: Georgia's graduated licensing law, TADRA, has maintained and in some instances increased in effectiveness over the 15.5 years since its inception. Though national research suggests that GDL laws are associated with increased crash rates among 18- to 19-year-old drivers, this has not occurred in Georgia; 18- and 19-year-olds demonstrated no change or reductions in FCR over the 20.5-year period evaluated. Declines were greatest for those driving behaviors targeted by the law. 相似文献
The objective of this paper is to identify strategies to improve the resilience of interagency communication between relief organizations and the community when dealing with an emergency. This research draws from frameworks including information theory, organization design, and how the private sector has learned and evolved from the challenges of information flow to provide guidance to disaster relief agencies. During times of emergency, private organizations as well as public authorities must coordinate in real time to create an effective response. When coordination is absent, failure results, as was seen after Hurricane Katrina and the Haiti Earthquake. Using data that the authors collected immediately after these disasters, two case studies of systemic failure are presented to extract lessons that might be used to improve communication resilience through coordination between parties in humanitarian relief operations. Recent emergency response trends are identified, and the paper argues that the persistence of response failures is not surprising, in part because response organizations normally operate independently, and their operations evolve at different rates. As a result, the organizational interfaces that enable rapid integration during a disaster naturally degrade and may be weak or absent. Integrating the literature on information processing theory and organization design with the data from the two case studies, the paper proposes that increasing the resilience of disaster response systems can be achieved by (1) improving the interoperability and information flow across organizational boundaries; (2) increasing the synergies between organizations on adapting new technology such as social media for the coordination of structured and unstructured data for use in decision-making, and (3) increasing the flexibility of relief organizations to use external resources from areas not affected by disasters on an opportunistic basis. The paper concludes by discussing resilience enhancing solutions including boundary spanning investments and argues that effective emergency response does not result from sporadic or intermittent efforts but rather requires sustained investment, continuous monitoring, and data collection. 相似文献
Herring (Clupea harengus pallasi) spawning sites in Puget Sound, Washington overlap spatially and temporally with blooms of Alexandrium catenella, a toxic dinoflagellate species responsible for paralytic shellfish poisoning. Consequently, newly hatched herring larvae
may be regularly exposed to the suite of dissolved paralytic shellfish toxins that are released into the water column from
toxic cells during blooms. To date, virtually nothing is known about the impacts of these neurotoxins on early developmental
stages of marine fish. In the present study, herring larvae at three ages, 0 days post hatch (dph), 4 dph, and 11 dph, were
exposed to dissolved saxitoxin (STX) in 24-h and multi-day exposures. All larvae were examined for sensorimotor function (i.e.
spontaneous swimming behavior and touch response). Significant reductions in spontaneous and touch-activated swimming behavior
occurred within 1 h of exposure. EC50s at 1 h of exposure were 1,500, 840, and 700 μg STX equiv. l−1 for larvae introduced to STX at 0, 4, and 11 dph, respectively. This progressive age-specific increase in STX-induced paralysis
suggests that older larvae were more sensitive to the toxin than younger larvae. Interestingly, herring larvae at all ages
exhibited a significant degree of neurobehavioral recovery within 4–24 h of continuous exposure relative to the 1-h time point.
This recovery of normal motor behaviors was not observed in previous studies with freshwater zebrafish (Danio rerio) larvae under the same continuous exposure conditions, suggesting that an adaptive detoxification or toxin sequestration
mechanism may have evolved in some species of marine fish larvae. Our data reveal that (1) dissolved STX is bioavailable to
marine finfish larvae, (2) the toxin is a paralytic agent with potencies that differ between developmental stages, and (3)
STX-induced sensorimotor inhibition occurs rapidly but is transient in marine larvae. Collectively, these results suggest
that dissolved algal toxins may have important sublethal effects on marine fish populations. 相似文献
African wild dogs ( Lycaon pictus ) are endangered largely because their population-density is low under all conditions. Interspecific competition with larger carnivores may be a factor limiting wild dog density. The density of wild dogs on a 2600-km2 area of the Selous Game Reserve (Tanzania) was 0.04 adults/km2. Spotted hyaena ( Crocuta crocuta ) density for the same area was estimated by audio playbacks as 0.32 hyaenas/km2. Lion ( Panthera leo ) density, determined from the ratio of hyaenas to lions, was 0.11 lions/km2. Across six ecosystems including Selous, there were strong negative correlations between wild dog and hyaena densities (r = −0.92; p = 0.01) and between wild dog and lion densities (r = −0.91; p = 0.03). Hyaenas out-numbered wild dogs by ratios ranging from 8:1 to 122:1. Ratios of lions to wild dogs ranged from 3:1 to 21:1. The diets of hyaenas and wild dogs overlap extensively; those of wild dogs and lions show less overlap. Where hyaenas are common and visibility is good, interference competition from hyaenas at wild dog kills is common and reduces wild dogs' feeding time. Where hyaena density is lower and visibility is poor, interference competition at wild dog kills is rare. Wild dogs are commonly killed by lions and occasionally by hyaenas. These data suggest that competition with spotted hyaenas may limit or exclude wild dogs when hyaena density is high. Competition with lions appears less intense, but direct predation by lions on wild dogs is important. Competition and predation by larger carnivores may be of broad importance to the conservation of wild dogs and other medium-sized carnivores. 相似文献
The impact of supplementing lipid emulsions rich in eicosapentaenoic acid (EmEPA), docosahexaenoic acid (EmDHA) or saturated fatty acids (EmCOCO) to a standard algal diet [3:1 mixture of Isochrysis galbana (T-iso) and Chaetoceros neogracile, St-diet] on Argopecten purpuratus broodstock was evaluated. Broodstock fecundity was compared as well as the egg quality in terms of lipid content, fatty acid composition and lipid class distribution. Fecundity was defined as the number of eggs released in the spawning process, since spawning was virtually complete. Results indicated that the total lipid content of the eggs of A. purpuratus was diet independent. A greater energy reserve was spent on a larger number of oocytes and not on bigger sized oocytes with a higher lipid content. The lipids supplied through the emulsions were at least partially allocated to the eggs, demonstrating that the fatty acid composition of the eggs could be manipulated, especially the neutral lipid fraction. Levels of EPA changed more rapidly than DHA levels, supporting the observation that they fulfilled an energetic and structural role, respectively. The St-diet supplemented with 50%EmCOCO resulted in a significantly higher fecundity compared to the algal diet supplemented with 25%EmEPA+25%EmDHA and the non-supplemented algal diet. It would seem that saturated fatty acids (SAFA) were more easily or preferentially incorporated in the female gonads of A. purpuratus. The relative content of SAFA and 18:2( n-6) in these eggs rose significantly. The relative content of the highly unsaturated fatty acids, EPA and DHA, on the other hand was substantially lower in the neutral lipid fraction, but hardly affected in the polar lipid fraction. It appeared that the maintenance of an adequate DHA/EPA ratio (approximately 1.2) was more important than the absolute levels of the two fatty acids, as long as a threshold value was reached. 相似文献
Natural radionuclides have been proposed as a means of assessing the transport of ozone (O3) and aerosols in the troposphere. Beryllium-7 (7Be) is produced in the upper troposphere and lower stratosphere by the interaction of cosmogenic particles with atmospheric nitrogen and oxygen. 7Be has a 53.29-day half-life (478 keV gamma) and is known to attach to fine particles in the atmosphere once it is formed. It has been suggested that O3 from aloft can be transported into rural and urban regions during stratospheric-tropospheric folding events leading to increased background levels of O3 at the surface. 7Be can be used as a tracer of upper atmospheric air parcels and the O3 associated with them. Aerosol samples with a 2.5-microm cutoff were collected during 12-hr cycles (day/night) for a 30-day period at Deer Park, TX, near Houston, in August-September of 2000, and at Waddell, AZ, near Phoenix, in June-July of 2001. A comparison of 7Be levels with 12-hr O3 averages and maxima shows little correlation. Comparison of nighttime and daytime O3 levels indicate that during the day, when mixing is anticipated to be higher, the correlation of 7Be with O3 in Houston is approximately twice that observed at night. This is consistent with mixing and with the anticipated loss of O3 by reaction with nitric oxide (NO) and dry deposition. At best, 30% of the O3 variance can be explained by the correlation with 7Be for Houston, less than that for Phoenix where no significant correlation was seen. This result is consistent with the intercept values obtained for 7Be correlations with either O3 24-hr averages or O3 12-hr maxima and is also in the range of the low O3 levels (25 ppb) observed at Deer Park during a tropical storm event where the O3 is attributable primarily to background air masses. That is, maximum background O3 level contributions from stratospheric sources aloft are estimated to be in the range of 15-30 ppb in the Houston, TX, and Phoenix, AZ, area, and levels above these are because of local tropospheric photochemical production. 相似文献