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31.
PROBLEM: Age and gender are frequently controlled for in studies of driving performance, but the effects of time of day or circadian cycles on performance are often not considered. Previous research on time of day effects of simulated driving is contradictory and provides little guidance for understanding the impact of these variables on results. METHODS: Using driving simulator data from 79 subjects ages 18 to 65, this paper focuses on the impact of age, gender, and time of day on the simulated driving performance of subjects who self-selected the time of participation. RESULTS: Time of day effects were consistently evident for drivers' speed overall and across different simulated environments. Drivers in the late afternoon period consistently drove significantly slower than drivers in other time periods. Age and gender affected speed such that women and those participants 50 and older tended to drive more slowly. Time of day also had an effect on reaction time and on speed variability measures. Gender did not have significant effects on reaction time or variability measures, but age effects were present. SUMMARY: Taken together, the results suggest that time of day effects should be considered as part of simulated driving performance, and that interactions between time of day and other variables, notably age, should be controlled for as part of future research. IMPACT ON INDUSTRY: Implications of these findings on current efforts for older driver testing are discussed. 相似文献
32.
Mengnjo J. Wirmvem Takeshi Oh Wilson Y. Fantong Samuel N. Ayonghe Jonathan N. Hogarh Justice Y. Suil Asobo Nkengmatia E. Asaah Seigo Ooki Gregory Tanyileke Joseph V. Hell 《环境科学学报(英文版)》2014,26(4):801-809
Rainwater characteristics can reveal emissions from various anthropogenic and natural sources into the atmosphere. The physico-chemical characteristics of 44 monthly rainfall events (collected between January and December 2012) from 4 weather stations (Bamenda, Ndop plain, Ndawara and Kumbo) in the Bamenda Highlands (BH) were investigated. The purpose was to determine the sources of chemical species, their seasonal inputs and suitability of the rainwater for drinking. The mean pH of 5 indicated the slightly acidic nature of the rainwater. Average total dissolved solids (TDS) were low (6.7 mg/L), characteristic of unpolluted atmospheric moisture/air. Major ion concentrations (mg/L) were low and in the order K+ 〉 Ca2+ 〉 Mg2~ 〉 Na+ for cations and NO3 〉〉 HCO3 〉 SO] 〉 CI- 〉 PO3- 〉 F- for anions. The average rainwater in the area was mixed Ca-Mg-SO4-CI water type. The CI-/Na+ ratio (1.04) was comparable to that of seawater (1.16), an indication that N a+ and CI originated mainly from marine (Atlantic Ocean) aerosols. High enrichments of Ca2+, Mg2+ and SO2- to Na+ ratios relative to seawater ratios (constituting 44% of the total ions) demonstrated their terrigenous origin, mainly from Saharan and Sahelian arid dusts. The K+/Na+ ratio (2.24), which was similar to tropical vegetation ash (2.38), and NO3 was essentially from biomass burning. Light (〈 100 mm) pre-monsoon and post-monsoon convective rains were enriched in major ions than the heavy (〉 100 mm) monsoon rains, indicating a high contribution of major ions during the low convective showers. Despite the acidic nature, the TDS and major ion concentrations classified the rainwater as potable based on the WHO guidelines. 相似文献
33.
Cuyler Christine Rowell Janice Adamczewski Jan Anderson Morgan Blake John Bretten Tord Brodeur Vincent Campbell Mitch Checkley Sylvia L. Cluff H. Dean Côté Steeve D. Davison Tracy Dumond Mathieu Ford Barrie Gruzdev Alexander Gunn Anne Jones Patrick Kutz Susan Leclerc Lisa-Marie Mallory Conor Mavrot Fabien Mosbacher Jesper Bruun Okhlopkov Innokentiy Mikhailovich Reynolds Patricia Schmidt Niels Martin Sipko Taras Suitor Mike Tomaselli Matilde Ytrehus Bjørnar 《Ambio》2020,49(3):805-819
Ambio - Muskoxen (Ovibos moschatus) are an integral component of Arctic biodiversity. Given low genetic diversity, their ability to respond to future and rapid Arctic change is unknown, although... 相似文献
34.
Stromberg JC Lite SJ Rychener TJ Levick LR Dixon MD Watts JM 《Environmental monitoring and assessment》2006,115(1-3):145-173
A portion of Arizona’s San Pedro River is managed as a National Riparian Conservation Area but is potentially affected by ground-water withdrawals beyond the conservation area borders. We applied an assessment model to the Conservation Area as a basis for monitoring long-term changes in riparian ecosystem condition resulting from changes in river water availability, and collected multi-year data on a subset of the most sensitive bioindicators. The assessment model is based on nine vegetation bioindicators that are sensitive to changes in surface water or ground water. Site index scores allow for placement into one of three condition classes, each reflecting particular ranges for site hydrology and vegetation structure. We collected the bioindicator data at 26 sites distributed among 14 reaches that had similar stream flow hydrology (spatial flow intermittency) and geomorphology (channel sinuosity, flood-plain width). Overall, 39% of the riparian corridor fell within condition class 3 (the wettest condition), 55% in condition class 2, and 6% in the driest condition class. Condition class 3 reaches have high cover of herbaceous wetland plants (e.g., Juncus and Schoenoplectus spp.) along the perennial stream channel and dense, multi-aged Populus-Salix woodlands in the flood plain, sustained by shallow ground water in the stream alluvium. In condition class 2, intermittent stream flows result in low cover of streamside wetland herbs, but Populus-Salix remain abundant in the flood plain. Perennial wetland plants are absent from condition class 1, reflecting highly intermittent stream flows; the flood plain is vegetated by Tamarixa small tree that tolerates the deep and fluctuating ground water levels that typify this reach type. Abundance of herbaceous wetland plants and growth rate of Salix gooddingii varied between years with different stream flow rates, indicating utility of these measures for tracking short-term responses to hydrologic change. Repeat measurement of all bioindicators will indicate long-term trends in hydro-vegetational condition. 相似文献
35.
Ronald Leroy Mickelsen Joseph Wood Michael Worth Calfee Shannon Serre Shawn Ryan Abderrahmane Touati Francis Robbins Delafield Lola Denise Aslett 《补救:环境净化治理成本、技术与工艺杂志》2019,30(1):47-56
Remediation and recovery efforts after a release of Bacillus anthracis (anthrax) spores may be difficult and costly. In addition, response and recovery technologies may be focused on critical resources, leaving the small business or homeowner without remediation options. This study evaluates the efficacy of relatively low levels of hydrogen peroxide vapor (HPV) delivered from off‐the‐shelf equipment for the inactivation of Bacillus spores within an indoor environment. Decontamination evaluations were conducted in a house using both Bacillus atrophaeus var. globigii (Bg; as surrogates for B. anthracis) inoculated on the carpet and galvanized metal as coupons and Geobacillus stearothermophilus (Gs) as biological indicators on steel. The total decontamination time ranged from 4 to 7 days. Using the longer exposure times, low concentrations of HPV (average levels below 20 parts per million) effectively inactivated Bg and Gs spores on the materials tested. The HPV was generated with commercial humidifiers and household‐strength hydrogen peroxide solutions. The presence of home furnishings did not have a significant impact on HPV efficacy. This simple, inexpensive, and effective decontamination method could have significant utility for remediation following a B. anthracis spore release, such as following a terrorist attack. 相似文献
36.
37.
Shelly L. Miller Peter Scaramella Joseph Campe Cynthia W. Goss Sandra Diaz-Castillo Ed Hendrikson Carolyn DiGuiseppi Jill Litt 《Atmospheric environment (Oxford, England : 1994)》2009,43(35):5661-5667
An indoor air quality assessment was conducted on 100 homes of recent Mexican immigrants in Commerce City, Colorado, an urban industrial community north of Denver. Head of households were administered a family health survey, filled out an activity diary, and participated in a home inspection. Carbon monoxide (CO) and carbon dioxide (CO2) were measured for 24 h inside the main living area and outside of the homes. Harvard Impactors were used to collect 24-h samples of PM2.5 at the same locations for gravimetric analysis. Dust samples were collected by vacuuming carpeting and flooring at four locations within the home and analyzed by ELISA for seven allergens. Mean indoor and outdoor PM2.5 levels were 27.2 and 8.5 μg m−3, respectively. Indoor PM2.5 and CO2 were elevated in homes for which the number of hours with door/window open was zero compared to homes in which the number of hours was high (>15 h). Indoor PM2.5 levels did not correlate with outdoor levels and tended to increase with number of inhabitants, and results indicate that the source of indoor particles were occupants and their activities, excluding smoking and cooking. Mean indoor CO2 and CO levels were 1170 and 2.4 ppm, respectively. Carbon monoxide was higher than the 24-h National Ambient Air Quality Standard in 3 of the homes. The predominant allergens were cat (Fel d 1) and mouse (Mus m 1) allergens, found in 20 and 34 homes, respectively. 相似文献
38.
John E. Yorks Anne M. Thompson Everette Joseph Sonya K. Miller 《Atmospheric environment (Oxford, England : 1994)》2009,43(11):1827-1838
Ozone profiles are often used to investigate day-to-day and year-to-year variability in origins of free tropospheric ozone. With this in mind, more than 50 ozonesonde launches were conducted in Beltsville, MD, during the summers of 2004 through 2007. Budgets of free tropospheric ozone were calculated for each ozone profile in the four summers using a laminar identification (LID) method and unusual episodes were analyzed with respect to meteorological variables. The laminar method showed that stratosphere-to-troposphere transport (ST) accounted for greater than 50% of the free tropospheric ozone column on 17% of days sampled, a more pronounced influence than regional convective and lightning (RCL) sources. The ST origins were confirmed with trajectories, and tracers (water vapor and potential vorticity). The amount of free tropospheric ozone from ST and RCL sources varied from year-to-year (up to 13%) and can be explained by differences in mean meteorological patterns. On average, almost 30% of the free tropospheric column was attributed to ST influence, about twice as much as RCL, although the LID method may not capture weeks-old lightning influences as in a chemical model. The prevalence of ST ozone in summertime Beltsville soundings was similar to six sounding sites in the IONS-04 campaign [Thompson, A.M., et al., 2007b. Intercontinental Transport Experiment Ozonesonde Network Study (IONS, 2004): 1. Summertime upper tropospheric/lower stratosphere ozone over northeastern North America. J. Geophys. Res. 112, D12S12; Thompson, A.M., et al., 2007c. Intercontinental Transport Experiment Ozonesonde Network Study (IONS, 2004): 2. Tropospheric ozone budgets and variability over northeastern North America. J. Geophys. Res. 112, D12S13.] and to statistics from a 30 year climatology of European soundings [Collette, A., Ancellet, G., 2005. Impact of vertical transport processes on the tropospheric ozone layering above Europe. Part II: Climatological analysis of the past 30 years. Atmos. Environ. 39, 5423–5435]. The Beltsville record also demonstrated the value of soundings for air quality forecasting in an urban area. The 22 nighttime soundings collected over Beltsville in 2004–2007 can be divided into distinct polluted and unpolluted subsets, the former 20 ppbv higher in residual layer ozone (1 km) than the latter. These distinctions propagated to daytime differences of 10 ppbv at the surface in the Washington, DC, area, with the high-ozone residual layers leading to non-attainment of the National Ambient Air Quality Standard for ozone. More frequent ozone observations aloft appear essential for better understanding ozone variability and for enabling air quality modelers to achieve more accurate ozone forecasts. 相似文献
39.
Chester W. Spicer Michael W. Holdren Kenneth A. Cowen Darrell W. Joseph Jan Satola Bradley Goodwin Howard Mayfield Alexander Laskin M. Lizabeth Alexander John V. Ortega Matthew Newburn Robert Kagann Ram Hashmonay 《Atmospheric environment (Oxford, England : 1994)》2009,43(16):2612-2622
Aircraft emissions affect air quality on scales from local to global. More than 20% of the jet fuel used in the U.S. is consumed by military aircraft, and emissions from this source are facing increasingly stringent environmental regulations, so improved methods for quickly and accurately determining emissions from existing and new engines are needed. This paper reports results of a study to advance the methods used for detailed characterization of military aircraft emissions, and provides emission factors for two aircraft: the F-15 fighter and the C-130 cargo plane. The measurements involved outdoor ground-level sampling downstream behind operational military aircraft. This permits rapid change-out of the aircraft so that engines can be tested quickly on operational aircraft. Measurements were made at throttle settings from idle to afterburner using a simple extractive probe in the dilute exhaust. Emission factors determined using this approach agree very well with those from the traditional method of extractive sampling at the exhaust exit. Emission factors are reported for CO2, CO, NO, NOx, and more than 60 hazardous and/or reactive organic gases. Particle size, mass and composition also were measured and are being reported separately. Comparison of the emissions of nine hazardous air pollutants from these two engines with emissions from nine other aircraft engines is discussed. 相似文献
40.
Fuchaka Waswa Godfrey Netondo Lucy Maina Tabitha Naisiko Joseph Wangamati 《Journal of Agricultural and Environmental Ethics》2009,22(5):463-475
Although contract sugarcane farming is the most dominant and popular land use among farmers in Nzoia Sugarbelt, results from
a 2007 study suggests that the intended goal of increasing farmers’ incomes seems to have failed. With a mean monthly income
of Kenya Shillings 723 (US $ 10) from an average cane acreage of 0.38 hectares, it would be difficult for a household of eight
family members to meet their basic needs and lead a decent life. Analysis of farmer statements showed that up to 86% of the
changes in net income were significantly determined by six cost variables as a group (i.e., acreage, tillage costs, seedcane
costs, transport costs, yield, and farmer’s education level). Area under sugarcane had the greatest influence on net income
whereby an increase in one hectare under cane would result in an increase of Kenya Shillings 110,427 in net income (per crop
cycle of 21 months), holding other variables constant. This translates into Kenya shillings 5,258 per month (or 175 per day
per household, or for a family of eight people—KES 22 or US $ 10) from an average cane acreage of 0.38 hectares, it would be difficult for a household of eight
family members to meet their basic needs and lead a decent life. Analysis of farmer statements showed that up to 86% of the
changes in net income were significantly determined by six cost variables as a group (i.e., acreage, tillage costs, seedcane
costs, transport costs, yield, and farmer’s education level). Area under sugarcane had the greatest influence on net income
whereby an increase in one hectare under cane would result in an increase of Kenya Shillings 110,427 in net income (per crop
cycle of 21 months), holding other variables constant. This translates into Kenya shillings 5,258 per month (or 175 per day
per household, or for a family of eight people—KES 22 or US 0.3) per member, which is far below the international standard
of absolute poverty. Key net income depressors were tillage, seedcane, and transportation costs, all of which were determined
by the company with no input from farmers. To bridge income gaps between the company and farmers in favor of sustainable community
livelihoods, this paper argues strongly for the need to institutionalize Corporate Social Responsibility within the daily
operations of the company particularly to address net-income depressors. Ten key building blocks for such a policy for Nzoia
Sugar Company are suggested, based on farmers’ responses and ethical considerations. 相似文献