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21.
When an explosive detonates or a propellant or flare burns, consumption of the energetic filler should be complete but rarely is, especially in the presence of large amounts of non-combustible materials. Herein we examine three types of perchlorate-containing devices to estimate their potential as sources of contamination in their normal mode of functioning. Road flares, rocket propellants and ammonium nitrate (AN) emulsion explosives are potentially significant anthropogenic sources of perchlorate contamination. This laboratory evaluated perchlorate residue from burning of flares and propellants as well as detonations of ammonium nitrate emulsion explosives. Residual perchlorate in commercial products ranged from 0.094 mg perchlorate per gram material (flares) to 0.012 mg perchlorate per gram material (AN emulsion explosives). The rocket propellant formulations, prepared in this laboratory, generated 0.014 mg of perchlorate residue per gram of material.  相似文献   
22.
Acute respiratory infections are common in children below 5 years and recent studies suggest a possible link with air pollution. In this study, we investigated the association between ambient nitrogen oxides (NOx) and bronchitis or upper airway inflammation.This longitudinal study was conducted in Teplice and Prachatice districts, Czech Republic. Children were followed from birth to 4.5 years of age. Data were compiled from medical records at delivery and at follow up, and from self-administered questionnaires from the same two time points. Air pollution monitoring data were used to estimate exposure over five different averaging periods ranging from three to 45 days prior to an episode. To quantify the association between exposure and outcome, while accounting for repeated measure correlation we conducted logistic regression analysis using generalized estimating equations.During the first 2 years of life, the adjusted rate ratio for bronchitis associated with interquartile increase in the 30-day average NOx was 1.31 [95% confidence interval (CI): 1.07, 1.61] and for two to 4.5 year olds, it was 1.23 (95% CI: 1.01, 1.49). The 14-day exposure also had stable association across both age groups: below 2 years it was 1.25 (95% CI: 1.06, 1.47) and for two to 4.5 years it was 1.21 (95% CI: 1.06, 1.39). The association between bronchitis and NOx increased with child's age in the under 2 years group, which is a relatively novel finding.The results demonstrate an association between NOx and respiratory infections that are sufficiently severe to come to medical attention. The evidence, if causal, can be of public health concern because acute respiratory illnesses are common in preschool children.  相似文献   
23.
Environmental Management - In the United States, forest governance practices have utilized a variety of public participation mechanisms to improve decision-making and instill public legitimacy....  相似文献   
24.
While some scholars have found that government post-disaster assistance supports the incumbent, others have shown that incumbent effects among beneficiaries are imperceptible or negative. This article contributes to this debate by using a regression discontinuity design of households affected by Tropical Cyclone Winston in Fiji to show that the type of assistance provided is an important variable in understanding the effects of aid on perceptions of the government. Residents of Fiji who received a post-disaster cash transfer are up to 20 per cent more likely to be very satisfied with the government than are those who did not. The probability further increases if the cash transfer was provided along with in-kind benefits or vouchers, but it is not affected if beneficiaries were also encouraged to use their own pension savings. This paper provides evidence in favour of the ‘attentive citizen’ theory by demonstrating that beneficiaries actively appraise government responses; it also reveals possible effects of elite capture on the relationship between the government and beneficiaries.  相似文献   
25.
Ranked-set sampling from a finite population is considered in this paper. Three sampling protocols are described, and procedures for constructing nonparametric confidence intervals for a population quantile are developed. Algorithms for computing coverage probabilities for these confidence intervals are presented, and the use of interpolated confidence intervals is recommended as a means to approximately achieve coverage probabilities that cannot be achieved exactly. A simulation study based on finite populations of sizes 20, 30, 40, and 50 shows that the three sampling protocols follow a strict ordering in terms of the average lengths of the confidence intervals they produce. This study also shows that all three ranked-set sampling protocols tend to produce confidence intervals shorter than those produced by simple random sampling, with the difference being substantial for two of the protocols. The interpolated confidence intervals are shown to achieve coverage probabilities quite close to their nominal levels. Rankings done according to a highly correlated concomitant variable are shown to reduce the level of the confidence intervals only minimally. An example to illustrate the construction of confidence intervals according to this methodology is provided.  相似文献   
26.
The quality of stationary source emission factors is typically described using data quality ratings, which provide no quantification of the precision of the emission factor for an average source, nor of the variability from one source to another within a category. Variability refers to actual differences caused by differences in feedstock composition, design, maintenance, and operation. Uncertainty refers to lack of knowledge regarding the true emissions. A general methodology for the quantification of variability and uncertainty in emission factors, activity factors, and emission inventories (EIs) is described, featuring the use of bootstrap simulation and related techniques. The methodology is demonstrated via a case study for a selected example of NOx emissions from coal-fired power plants. A prototype software tool was developed to implement the methodology. The range of interunit variability in selected activity and emission factors was shown to be as much as a factor of 4, and the range of uncertainty in mean emissions is shown to depend on the interunit variability and sample size. The uncertainty in the total inventory of -16 to +19% was attributed primarily to one technology group, suggesting priorities for collecting data and improving the inventory. The implications for decision-making are discussed.  相似文献   
27.
The objectives of this paper are to (1) quantify variability in hourly utility oxides of nitrogen (NO(x)) emission factors, activity factors, and total emissions; (2) investigate the autocorrelation structure and evaluate cyclic effects at short and long scales of the time series of total hourly emissions; (3) compare emissions for the ozone (O3) season versus the entire year to identify seasonal differences, if any; and (4) evaluate interannual variability. Continuous emissions monitoring data were analyzed for 1995 and 1998 for 32 units from nine baseload power plants in the Charlotte, NC, airshed. Unit emissions have a strong 24-hr cycle attributable primarily to the capacity factor. Typical ranges of the coefficient of variation for emissions at a given hour of the day were from 0.2 to 0.45. Little difference was found when comparing weekend emissions with the entire week or when comparing the O3 season with the entire year. There were substantial differences in the mean and standard deviation of emissions when comparing 1995 and 1998 data, indicative of the effect of retrofits of control technology during the intervening time. The wide range of variability and its autocorrelation should be accounted for when developing probabilistic utility emission inventories for analysis of near-term future episodes.  相似文献   
28.
Incentive instruments (effluent charges) are theoretically expected to be preferred to direct regulations (individual emission ceilings) by university-employed, theoretically inclined politically right-wing, professional economists living in a market-oriented country, ceteris paribus. Public sector employed, politically left-wing, professional economists living in a country with a long tradition of government involvement prefer the regulatory approach, ceteris paribus. These theoretical hypotheses tend to be supported by a bivariate probit analysis based on a survey of more than 1400 economists in five countries.  相似文献   
29.
Non-hibernating pikas collect winter food reserves and store them in hay piles. Individualization of alarm calls might allow discrimination between colony members and conspecifics trying to steal food items from a colony pile. We investigated vocal posture, vocal tract length, and individual acoustic variation of alarm calls, emitted by wild-living Altai pikas Ochotona alpina toward a researcher. Recording started when a pika started calling and lasted as long as possible. The alarm call series of 442 individual callers from different colonies consisted of discrete short (0.073–0.157 s), high-frequency (7.31–15.46 kHz), and frequency-modulated calls separated by irregular intervals. Analysis of 442 discrete calls, the second of each series, revealed that 44.34% calls lacked nonlinear phenomena, in 7.02% nonlinear phenomena covered less than half of call duration, and in 48.64% nonlinear phenomena covered more than half of call duration. Peak frequencies varied among individuals but always fitted one of three maxima corresponding to the vocal tract resonance frequencies (formants) calculated for an estimated 45-mm oral vocal tract. Discriminant analysis using variables of 8 calls per series of 36 different callers, each from a different colony, correctly assigned over 90% of the calls to individuals. Consequently, Altai pika alarm calls are individualistic and nonlinear phenomena might further increase this acoustic individualization. Additionally, video analysis revealed a call-synchronous, very fast (0.13–0.23 s) folding, depression, and subsequent re-expansion of the pinna confirming an earlier report of this behavior that apparently contributes to protecting the hearing apparatus from damage by the self-generated high-intensity alarm calls.  相似文献   
30.
Smart characterization approaches apply the latest high‐resolution site characterization methods to find the contaminant mass flux, by integrating relative permeability mapping, classical hydrostratigraphy interpretation, and high‐density groundwater and saturated soil sampling. The key factor that makes Smart characterization different is the application of quantitative saturated soil sampling in less permeable slow advection and storage zones to diagnose plume maturity and understand its implications for remedy selection and performance. Because direct sensing tools like the membrane interface probe are capable of providing screening‐level assessments for hydrocarbons and chlorinated solvents in storage zones, but not 1,4‐dioxane, the recommended Smart approach involves application of specialized high‐capacity mobile laboratories or rapid turn‐around using fixed commercial labs. In addition to the benefit of rapidly characterizing sites, Smart characterization facilitates a flux‐based conceptual site model, which allows stakeholders to focus remedies on the mobile portion of the contaminant mass or, in effect, the mass that matters. Through systematic planning and implementation, predesign characterization can be completed to optimize source and plume remedy strategies, balancing investment in Smart characterization with reductions in total life‐cycle costs to ensure that an appropriate return on investigation is obtained.  © 2016 Wiley Periodicals, Inc.  相似文献   
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