Background: Two of the 3 standardized field sobriety tests that U.S. law enforcement uses at roadside checks have a postural equilibrium component to them. Those tests have been validated to detect impairment caused by blood alcohol concentrations (BACs) of 0.08 g/dL or above. Many medical and traffic safety associations support a lower limit, and one state, Utah, has passed a law to lower the limit to 0.05 g/dL. Many studies have examined the effects of alcohol on postural control (of which postural equilibrium is a component), with a consensus emerging that impairment is usually found at BACs greater than 0.06 g/dL. Most of these studies, however, had a relatively small number of subjects, usually between 10 and 30. The current study collected data from a much larger sample.
Objective: The objective of this study was to provide additional evidence that posture control is negatively affected at BACs greater than 0.06 g/dL or breath alcohol concentrations (BrACs) of 0.06 g/210 L.
Method: This was a between-subjects study, with BrAC group as the independent variable (5 levels: 0.00, 0.04, 0.06, 0.08, and 0.10 g/210 L); 4 measures of postural control as the dependent variables; and age, height, and weight as the covariates. Posture control was measured with a force-sensing platform connected to a computer. The feet's center of pressure (CoP) on the platform was recorded and the corresponding movement of the body in the anterior–posterior and lateral planes was derived. Participants (N = 96) were randomly assigned to one of the BrAC groups. Positive BrAC groups were compared to the zero BrAC group. Data were examined with hierarchical multiple regression.
Results: Adjusted for age, height, and weight, the main effect of lateral CoP with eyes open was not statistically significant. There was a statistically significant main effect of alcohol on anterior–posterior CoP excursion with eyes open and with eyes closed and lateral CoP excursion with eyes closed. For all 3 of those variables, only BrACs of 0.08 and 0.10 g/210 L produced differences against zero BrAC. Although the main effect of alcohol on Lateral CoP Excursion with eyes open was not statistically significant, the contrasts between 0 and 0.08 and 0 and 0.10 g/210L BrAC were in the hypothesized direction.
Conclusion: The current study did not directly address the issue of whether the sobriety tests are sensitive to BrACs of 0.05 g/210 L or above; rather, it provides additional evidence that postural control, one of the components of those tests, is relatively unaffected by BrACs lower than 0.08 g/210 L. Additional research is needed on the diagnostic characteristics of the sobriety tests at BrACs lower than 0.08 g/210 L. 相似文献
Abstract Chemical transport in soil is a major factor influencing soil and water contamination. Four soils and turfgrass thatch, representing a wide range of organic carbon OC content were studied to determine sorption Kd and Kf parameters for the insecticides chlorpyrifos and fonofos. The batch equilibrium method was used. The concentration of insecticide was measured in the solution as well as in the solid phase to determine the most accurate sorption data. Four soils and thatch were equilibrated for 24 h at 22 ± 1OC with aqueous insecticide solutions. Four concentrations of the insecticides, each <50% of their respective water solubilities, were selected for the experiments. After extraction with an organic solvent, the concentration of insecticides in the aqueous solution was determined by gas liquid chromatography using electron capture detection for chlorpyrifos, and nitrogen/phosphorus detection for fonofos. Data obtained were fitted to the log and simple linear form of the Freundlich equation. Mass balance Freundlich isotherm exponents n ranged between 0.82 and 0.93 for chlorpyrifos. 0.82 and 1.21 for fonofos, with r2 ≥ 0.97. Koc (percent of organic carbon %OC normalized Sorption coefficient) values were calculated by using experimentally developed Kd and Kf coefficients in relation to OC levels from 0.29 to 34.85%. Kd and Kf coefficients of both insecticides were positively correlated with OC (r2 ≥ 0.96). organic matter OM (r2≥ 0.96), and cation exchange capacity CEC (r2 ≥ 0.90). 相似文献
Abstract: Evaluating the relative amounts of water moving through the different components of the hydrological cycle is required for precise management and planning of water resources. An important aspect of this evaluation is the partitioning of streamflow into surface (quick flow) and base‐flow components. A prior study evaluated 40 different approaches for hydrograph‐partitioning on a field scale watershed in the Coastal Plain of the Southeastern United States and concluded that the Boughton’s method produced the most consistent and accurate results. However, its accuracy depends upon the proper estimation of: (1) the end of surface runoff, and (2) the fraction factor (α) that is function of many physical and hydrologic characteristics of a watershed. Proper identification of the end of surface runoff was accomplished by using a second derivative approach. Applying this approach to 12 years of separately measured surface and subsurface flow data from a field scale watershed (study area) proved to be accurate for 87% of the time. Estimation of the α value was accomplished in this study using two steps: (1) alpha was fitted to individual hydrographs: and, (2) a regression equation that determines these alpha values based on climatological factors (e.g., rainfall, evapotranspiration) was developed. Using these strategies improved the streamflow partitioning method’s performance significantly. 相似文献
Blood composition is commonly measured to assess exposure to and effects of metals on birds. In most of passerine species, only small volumes of blood may be sampled safely (<500 μL), which limit the measure of several markers of health status and chemical residues. Here, we documented the partitioning of Cd and Pb in the blood of European Blackbirds Turdus merula in order to propose usable relationships between whole blood concentrations (for which toxicological benchmarks exist) and those measured in the erythrocytes. Sixty-two blackbirds were trapped along a pollution gradient (smelter of Metaleurop Nord, Northern France). Blood was sampled and Cd and Pb concentrations were measured both in whole blood and in the erythrocytes only. Birds coming from the most contaminated sites exhibited high residues for both Cd and Pb. We assessed that 73% and 99% of Cd and Pb, respectively, were associated to erythrocytes. Strong linear relationships, that were not influenced by neither the age nor the sex, were established between whole blood residues and those of erythrocytes for Cd and Pb (adj-R2 = 0.78 and 0.93, respectively). Present findings are promising to optimize the use of small blood samples in order to investigate several responses relative to wildlife health status. 相似文献