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401.
Objective: The current study evaluates of the effects of lowering the blood alcohol concentration (BAC) limit from 0.10 to 0.08?g/dL across all 50 states in the United States. Our objectives were to (1) estimate the effects of the 0.08?g/dL BAC limit on drinking driver fatal crash rates; (2) compare the effects from early-adopting states to the effects of late-adopting states; (3) determine the effects on drivers with low BACs (0.01–0.07?g/dL) and high BACs (0.08+ g/dL); and (4) estimate the lives saved since 1983 due to the adoption of 0.08?g/dL BAC laws.

Methods: Our study examined annual data from the Fatality Analysis Reporting System (FARS) for each jurisdiction from 1982 through 2014. Our basic outcome measure was the ratio of drinking drivers (BAC ≥0.01?g/dL) to nondrinking drivers (BAC?=?0.00?g/dL). Covariates included 0.10 BAC laws, administrative license revocation (ALR) laws, seat belt laws, minimum legal drinking age (MLDA) laws, and unemployment rates. We utilized autoregressive integrated moving average (ARIMA) models for each state, where the implementation date of the law was modeled as a zero-order transfer function in the series, in addition to any extant trends that may have been occurring simultaneously. Before determining the specific impact of the implementation of 0.08?g/dL BAC laws, we conducted a time series analysis for each state. We tested for between-state mediating factors relating to our covariates.

Results: A total of 38 of the 51 jurisdictions showed that lowering the BAC limit was associated with reduced drinking driver fatal crash ratios, with 20 of those reductions being significant. The total effects showed a 10.4% reduction in annual drinking driver fatal crash rates, which is estimated to have saved an average of 1,736 lives each year between 1983 and 2014 and 24,868 lives in total. Implementing a BAC limit of 0.08?g/dL had significant impacts on both high- and low-BAC fatal crash ratios. Though early-adopting jurisdictions (1983–1999) demonstrated a larger decrease in fatal drinking driver crash ratios than did late-adopting jurisdictions (2000–2005), the results were not statistically significant (P?>?.05).

Conclusions: Our study of the effects of lowering the BAC from 0.10 to 0.08?g/dL in the United States from 1982 to 2014 showed an overall effect of 10.4% on annual drinking driver fatal crash rates, in line with other multistate studies. This research provides strong evidence of the relationship between lowering the BAC limit for driving and the general deterrent effect on impaired-driving fatal crash rates.  相似文献   
402.
Poaching, enforcement, and the efficacy of marine reserves.   总被引:1,自引:0,他引:1  
Marine reserves are promoted as an effective supplement to traditional fishery management techniques of harvest quotas and effort limitation. However, quantitative fishery models have ignored the impact of noncompliance (poaching). Here we link a model of a harvested fish population to a game-theoretic representation of fisherman behavior to quantify the effect of poaching on fishery yield and the enforcement effort required to maintain any desired level of reserve effectiveness. Although higher fish densities inside reserves will typically entice fishermen to poach, we show that the initial investment in enforcement efforts provides the greatest return on maintaining the benefits of the reserve to the fishery. Furthermore, we find that poaching eliminates the positive effect of fish dispersal on yield that is predicted by traditional models that ignore fisherman behavior. Our results broaden a fundamental insight from previous models of marine reserves, the effective equivalence of the harvest quota and reserve fraction, to the more realistic scenario in which fishermen attempt to maximize their economic payoffs.  相似文献   
403.
The Ecological Society of America has evaluated current U.S. national policies and practices on biological invasions in light of current scientific knowledge. Invasions by harmful nonnative species are increasing in number and area affected; the damages to ecosystems, economic activity, and human welfare are accumulating. Without improved strategies based on recent scientific advances and increased investments to counter invasions, harm from invasive species is likely to accelerate. Federal leadership, with the cooperation of state and local governments, is required to increase the effectiveness of prevention of invasions, detect and respond quickly to new potentially harmful invasions, control and slow the spread of existing invasions, and provide a national center to ensure that these efforts are coordinated and cost effective. Specifically, the Ecological Society of America recommends that the federal government take the following six actions: (1) Use new information and practices to better manage commercial and other pathways to reduce the transport and release of potentially harmful species; (2) Adopt more quantitative procedures for risk analysis and apply them to every species proposed for importation into the country; (3) Use new cost-effective diagnostic technologies to increase active surveillance and sharing of information about invasive species so that responses to new invasions can be more rapid and effective; (4) Create new legal authority and provide emergency funding to support rapid responses to emerging invasions; (5) Provide funding and incentives for cost-effective programs to slow the spread of existing invasive species in order to protect still uninvaded ecosystems, social and industrial infrastructure, and human welfare; and (6) Establish a National Center for Invasive Species Management (under the existing National Invasive Species Council) to coordinate and lead improvements in federal, state, and international policies on invasive species. Recent scientific and technical advances provide a sound basis for more cost-effective national responses to invasive species. Greater investments in improved technology and management practices would be more than repaid by reduced damages from current and future invasive species. The Ecological Society of America is committed to assist all levels of government and provide scientific advice to improve all aspects of invasive-species management.  相似文献   
404.
An osteological study of the dugong (sea cow) Dugong dugon (Müller) from India, based on complete skeletons of an adult male and a juvenile female indicated certain morphological variations with age. It has also revealed a close osteological similarity between the dugongs from India and the Red Sea. Based on a statistical analysis, regression equations for certain typical skull measurements have been calculated; these equations, characteristic of the dugong from India, could be used for comparing dugongs of different regions.  相似文献   
405.
This paper presents a study of the urban region of Miami, Fla. with consideration of energy flow and the relationship between energy theory and economics. Much of this work is based on the theories and work of Dr Howard T. Odum at the University of Florida. A theory of energy quality is presented which is an attempt to relate energies of different concentrations in their ability to do work. This theory allows comparison of the systems of man and nature. Another theory is proposed which seeks to describe the ability of a region to compete based on its flows of natural and fossil fuel energies.Economic, natural system, and energy data were compiled for the Miami urban region from 1950–1972. Cross-correlation of this data showed significant levels of correlation between the rate of change of fossil fuel use and the rates of change of population, budget, sales tax, income, building structure, and number of telephones. Calculation of several urban indicators for 1972 showed a fossil fuel energy density of 300 kcal/m2/day in the urbanized area, a per capita energy consumption of 53.8 × 106 kcal/capita/year, a ratio of natural to fossil fuel energies of 0.25, a developed area of 260 miles2 (673.4 km2), and a rate of development of 6.5 miles2 (16.8 km2) per year.An overall model of Miami is presented with flows and storages quantified for 1972. Based on this model a simpler model was simulated on an analog computer. This model consisted of a system of first-order in time, non-linear differential equations which included fossil fuel energy flows, main economic flows, external price functions, building structure, natural energies, and population. This model was simulated for several linearly increasing future price functions and several sets of future energy functions.Natural energies within the region were calculated by determining the land areas associated with various ecosystem types. Estimating the productivities of these systems on a per area basis allowed calculation of total energy flows. The energies associated with winds, tides, waves, and fresh/salt water concentration gradients were also determined. It was found that the ratio of natural to fossil fuel energy changed from 1.77 in 1950 to 0.25 in 1972.  相似文献   
406.
In Europe, regulatory thresholds restrict adventitious GM (genetically modified) presence in conventional crops. Minimum distances for the spatial separation of fields are often recommended to reduce field-to-field cross-pollination to an acceptable level. Field trials are typically the basis for setting separation distances. However, using records of wind direction and speed from weather stations across Europe, we predict theoretically that field-to-field windborne cross-pollination in maize, oilseed rape, sugar beet, and rice varies greatly according to the relative orientation of the GM and non-GM fields. Furthermore, at a given site and orientation from a GM field, we predict that the cross-pollination rate varies substantially from year to year. Consequently, even replicated field trials may inaccurately estimate typical levels of cross-pollination and therefore distort our perception of the separation distances required to achieve sub-threshold adventitious GM presence. We propose methods to predict the likely range in levels of cross-pollination based on the limited data typically available from field trials. Additionally, we suggest suitable time lags between peak flowering in adjacent fields that could be introduced to reduce cross-pollination to a specified level.  相似文献   
407.
Fluvial processes such as flooding and sediment deposition play a crucial role in structuring riparian plant communities. In rivers throughout the world, these processes have been altered by channelization and other anthropogenic stresses. Yet despite increasing awareness of the need to restore natural flow regimes for the preservation of riparian biodiversity, few studies have examined the effects of river restoration on riparian ecosystems. In this study, we examined the effects of restoration in the Ume River system, northern Sweden, where tributaries were channelized to facilitate timber floating in the 19th and early 20th centuries. Restoration at these sites involved the use of heavy machinery to replace instream boulders and remove floatway structures that had previously lined stream banks and cut off secondary channels. We compared riparian plant communities along channelized stream reaches with those along reaches that had been restored 3-10 years prior to observation. Species richness and evenness were significantly increased at restored sites, as were floodplain inundation frequencies. These findings demonstrate how river restoration and associated changes in fluvial disturbance regimes can enhance riparian biodiversity. Given that riparian ecosystems tend to support a disproportionate share of regional species pools, these findings have potentially broad implications for biodiversity conservation at regional or landscape scales.  相似文献   
408.
Male spottail darters (Etheostoma squamiceps) defend nest sites in which females deposit eggs over the course of several weeks. In laboratory experiments, I tested three predictions of the hypothesis that the presence of eggs increases the value of a nest site to male spottail darters: (1) males should preferentially defend nests with eggs over empty nests, and males that sired the eggs should (2) spend more time defending them and (3) consume less of their broods than should alloparent males. Parent males were tested using eggs they were guarding in the field; alloparents included males that were not defending eggs immediately prior to the experiment (inexperienced), and males that were defending eggs in the field when captured but were given eggs sired by a different male (experienced). In choice experiments in which males were offered nest sites differing only in the presence of eggs, males preferred to defend nest sites with eggs regardless of parental status. Parent males spent significantly more time defending eggs and consumed less of their broods than did inexperienced alloparent males. Experienced alloparent males were similar to parent males in brood defense but had levels of filial cannibalism similar to inexperienced males, suggesting that prior experience may influence brood defense but not egg consumption.  相似文献   
409.
A partially probabilistic blood lead prediction model has been developed, based on the US Environmental Protection Agency integrated exposure-uptake-biokinetic blood lead model (IEUBK model). This study translated the IEUBK model into a spreadsheet format. The uptake submodel incorporates uncertainty distributions for exposure and bioavailability parameters. The biokinetic submodel is duplicated with a table incorporating partitioning and decay of lead levels in the body. As a case study, the probabilistic model is applied to a lead exposure scenario involving a former smelter site in Sandy, Utah. The probabilistic model produces less biased estimates of means and standard deviations than the deterministic model. Parameter uncertainty is propagated in the model by the use of Monte Carlo simulation. Thus, sensitivity analysis is possible, and driving variables can be determined.  相似文献   
410.
Summary Non-random mating by size (NRMS) plays a central role in the study of sexual selection and the evolution of mating systems. Theory suggests that NRMS should be influenced by conflicting demands (e.g., predation risk, hunger); few experimental studies, however, have addressed these effects. We used a factorial experiment to examine the influence of predatory green sunfish and food deprivation on NRMS in male and female stream water striders, Aquarius remigis. As predicted by theory, food deprivation decreased the large-male mating advantage. The influence of predation risk, however, went against existing theory; that is, risk increased the large male mating advantage. The degree of large-male mating advantage was negatively related to a measure of the rate of male harassment of females. A behavioral mechanism that can explain these patterns emphasizes the contrasting effects of different competing demands on male harassment rates, female resistance and the role of male size in overcoming female resistance. Females usually resist male mating attempts. Successful mating occurs when males overcome female resistance. If harassment rates (of females by males) are low, larger males have a mating advantage over smaller males perhaps because females resist heavily and thus only larger males can overcome female resistance. If, however, male harassment rates are very high, female resistance might be swamped; mating should then be more random with respect to male size. Food deprivation increases gerrid activity and thus increases harassment rates which should then reduce NRMS. In contrast, risk decreases gerrid activity, thus decreasing harassment rates and increasing NRMS. Females did not show significant NRMS. Females did, however, show a pattern of change in NRMS that is consistent with male choice for larger females. Correspondence to: A. Sih  相似文献   
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