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21.
环境及生物样品中化学战剂的分析检测一直是禁化武领域的研究热点.离子迁移谱因具有分析快速、灵敏、可小型化等优点,成为现场快速检测化学战剂的有效手段.本文首先说明了离子迁移谱的基本原理和设备结构,阐述了非放射性离子化源的发展对检测对象广谱化的影响,介绍了离子迁移谱与热解吸、闭管采样、固相微萃取、吸气式冷凝器等前处理装置的结合,以及与色谱、质谱技术联用在复杂样品定性定量分析和数据处理等方面的研究进展,并对发展趋势进行了展望.  相似文献   
22.
IntroductionThis article presents a health and safety intervention model and the use of process evaluation to assess a participatory ergonomic intervention.MethodThe effectiveness of the Ergonomic Program Implementation Continuum (EPIC) was assessed at six healthcare pilot sites in Ontario, Canada. The model provided a framework to demonstrate evaluation findings.ResultsParticipants reported that EPIC was thorough and identified improvements related to its use. Participants believed the program contributed to advancing an organizational culture of safety (COS). Main barriers to program uptake included resistance to change and need for adequate funding and resources. The dedication of organizational leaders and consultant coaches was identified as essential to the program's success.Impact on IndustryIn terms of impact on industry, findings contribute to the evidence-based knowledge of health and safety interventions and support use of the framework for creating a robust infrastructure to advance organizational COS and link staff safety and wellness with patient safety in healthcare.  相似文献   
23.
Environmental Geochemistry and Health - In recent years, the study of the influence of nanoparticles (NPs) on the environment has attracted much interest as nanotechnology is becoming the key...  相似文献   
24.
Hydrogen sulfide (H2S) is an endogenous gaseous molecule, functioning as a physiological regulator. This study aimed to investigate the role of H2S in atherosclerosis. Rabbits receiving high cholesterol were given atorvastatin (10 mg/kg/day, orally) or sodium sulfide (1.1 mg/kg/day, intramuscular) 2 weeks after commencement of high-cholesterol diet and continued for 4 weeks. Serum lipid profiles, lipid peroxidation indexed as malondialdehyde, glutathione, superoxide dismutase, the vascular adhesion molecule-1, and aortic vascular endothelial growth factor were determined. Rabbits receiving a high-cholesterol diet showed elevated levels of total serum cholesterol, triglycerides, low-density lipoprotein cholesterol, malondialdehyde and vascular adhesion molecule-1, and aortic vascular endothelial growth factor expression and lower levels of high-density lipoprotein cholesterol, glutathione, and superoxide dismutase. Treatment with atorvastatin and sodium sulfide has beneficial effects on serum lipid profile, oxidative damage, vascular adhesion molecule-1, and aortic expression of vascular endothelial growth factor.  相似文献   
25.
The kinetics of the degradation of trace nitrobenzene (NB) by a granular activated carbon (GAC) enhanced microwave (MW)/hydrogen peroxide (H2O2) system was studied. Effects of pH, NB initial concentration and tert-butyl alcohol on the removal efficiency were examined. It was found that the reaction rate fits well to first-order reaction kinetics in the MW/GAC/H2O2 process. Moreover, GAC greatly enhanced the degradation rate of NB in water. Under a given condition (MW power 300 W, H2O2 dosage 10 mg/L, pH 6.85 and temperature (60±5)℃), the degradation rate of NB was 0.05214 min-1 when 4 g/L GAC was added. In general, alkaline pH was better for NB degradation; however, the optimum pH was 8.0 in the tested pH value range of 4.0-12.0. At H2O2 dosage of 10 mg/L and GAC dosage of 4 g/L, the removal of NB was decreased with increasing initial concentrations of NB, indicating that a low initial concentration was beneficial for the degradation of NB. These results indicated that the MW/GAC/H2O2 process was effective for trace NB degradation in water. Gas chromatography-mass spectrometry analysis indicated that a hydroxyl radical addition reaction and dehydrogenation reaction enhanced NB degradation.  相似文献   
26.
Environmental Geochemistry and Health - Modeling metal sorption in soils is of great importance to predict the fate of heavy metals and to assess the actual risk driven from pollution. The present...  相似文献   
27.
The SPARROW (SPAtially Referenced Regressions On Watershed attributes) model was used to evaluate the spatial distribution of total nitrogen (TN) sources, loads, watershed yields, and factors affecting transport and decay in the stream network of California and portions of adjacent states for the year 2002. The two major TN sources to local catchments on a mass basis were fertilizers and manure (51.7%) and wastewater discharge (15.9%). Other sources contributed < 12%. Fertilizer use is widespread in the Central Valley region of California, and also important in several other regions because of the diversity of California agriculture. Precipitation, sand content of surficial soils, wetlands, and tile drains were important for TN movement to stream reaches. Median streamflow in the study area is about 0.04 m3/s. Aquatic losses of nitrogen were found to be most important in intermittent and small to medium sized streams (0.2‐14 m3/s), while larger streams showed less loss, and therefore are important for TN transport. Nitrogen loss in reservoirs was found to be insignificant, possibly because most of the larger ones are located upstream of nitrogen sources. The model was used to show loadings, sources, and tributary inputs to several major rivers. The information provided by the SPARROW model is useful for determining both the major sources contributing nitrogen to streams and the specific tributaries that transport the load.  相似文献   
28.
In polygynous mammals, males are usually responsible for gene flow while females are predominantly philopatric. However, there is evidence that in a few mammalian species female offspring may disperse to avoid breeding with their father when male tenure exceeds female age at maturity. We investigated offspring dispersal and local population structure in the Neotropical bat Lophostoma silvicolum. The mating system of this species is resource defense polygyny, with the resource being active termite nests, excavated by single males, which are then joined by females. We combined field observations of 14 harems during 3 years and data about the genetic structure within and between these groups, calculated with one mitochondrial locus and nine nuclear microsatellite loci. The results show that both male and female offspring disperse before maturity. In addition, we estimated life span of excavated termite nests and the duration they were occupied by the same male. Our findings suggest that long male tenure of up to 30 months is indeed a likely cause for the observed dispersal by female offspring that can reach maturity at a low age of 6 months. We suggest that dispersal by offspring of both sexes may occur quite frequently in polygynous tropical bats and thus generally may be more common in mammals than previously assumed.  相似文献   
29.
The type of control at intersections has a major effect on the operation of any urban corridor. Different predefined procedures are available to calculate some of the main operational characteristics, such as capacity, delay, and level of service, in order to select the best type of control. However, there are other important factors that affect major arterials operational characteristics, factors that are not fully addressed, such as the impact of emissions. In this study, a microscopic simulation approach using VISSIM and MOVES was developed to assess the environmental effect of converting four three-lane roundabouts to signalized intersections along a heavily congested urban corridor in Qatar. A decision was made to switch all roundabouts to traffic signals for better operations. Preliminary results indicated that the signal control outperformed the roundabout in the range of 37% to 43% reduction in emissions. A more detailed analysis revealed that roundabout corridor operations’ effects on emission rates are divergent from those of signalized corridors, particularly upstream and downstream of the intersections. Immediate roundabout upstream approaches are driver behavior dependent, characterized by substantial coasting at lower speeds and subsequent re-accelerating with less idling, described as acceleration events, which resulted in high emission rates, while signalized corridors are signal timing dependent, characterized by ample idling with less coasting and re-acceleration, resulting in reduced emission rates. The results also revealed that there was no significant difference between emission rates in the vicinity of the two types of control. Both recorded nearly the same emission rate.

Implications: A microscopic simulation approach using VISSIM and MOVES was developed to assess the environmental effect of converting four three-lane roundabouts to signalized intersections along a heavily congested urban corridor in Doha, Qatar. Intersection geometries along with the control type have significant impact on emission rates and play a major role in assessing environmental impacts. US EPA MOVES was calibrated to Qatar conditions which can be used to estimate emission factors and quantify vehicular emissions along other corridors in the country. The results can also be beneficial for other countries within the region.  相似文献   

30.
Environmental Geochemistry and Health - The results of biogeochemical and bioindication studies on the resistance of natural populations of macrophyte plant—cattail (Typha australis Schum....  相似文献   
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