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831.
Hand injuries form a significant proportion of all workplace injuries. They are costly to treat, and lead to significant loss of time at work. This paper has two parts. First, there is a review of the literature that discusses prevalence of hand injury, and the significance of hand roles and handedness in industrial injuries. The second part represents an initial attempt to document the roles of the two hands in a particular industry, the metal manufacturing industry. The purpose of this survey of 30 different work stations in seven different industrial plants was to see whether there is a significant bias in terms of movement requirements for one or the other hand, leading to a possible differential risk of injury for the left and right hands. Overall, there was no clear bias favoring the right hand in activities assigned to the hands in seven different movement categories (MTM). However, the location of emergency controls favored the right hand unequivocally. The implications of biases favoring the left/right hand for safety of machine operation are discussed in the light of current findings on left/right hand performance in right- and lefthanders.  相似文献   
832.
The use of stable-hydrogen isotopes (deltaD) has become a common tool for estimating geographic patterns of movement in migratory animals. This method relies on broad and relatively predictable geographic patterning in deltaD values of precipitation, but these patterns are not estimated without error. In addition, deltaD measurements are relatively imprecise, particularly for organic tissue. Most models for estimating geographic locations have ignored these sources of error. Common modeling approaches include regression, range-matching, and likelihood-based assignment tests (including discriminant analysis). Here, we show the benefits of a simple stochastic extension to likelihood-based assignment tests that incorporates two estimable sources of error and describe the resulting influence on the certainty of assigning breeding origins for wintering American Redstarts (Setophaga ruticilla), a small Nearctic-Neotropical migratory bird. Through simulation, we incorporated both spatial interpolation error associated with models of deltaD in precipitation and analytical error associated with the measurement of deltaD in tissue samples. In general, assignments that did not include these sources of error fell within the ranges of the stochastic results, but the difference in proportion of birds assigned to any one breeding region varied by as much as 54%. To explore how the distribution of assignments generated from error models influenced the application of these results, we developed a simple model of winter habitat loss. We removed the proportion of Redstarts wintering at a particular site from the global population and then used the isotope-based assignments to predict the resulting population declines for each breeding region. This gave distributions of change in population sizes, some of which included no change or even a population increase. The sources of error we modeled may challenge the degree of certainty in the use of stable-isotope-based data on connectivity to predict population dynamics of migratory animals. We suggest that stronger inference will result from incorporating these sources of error into future studies that use deltaD or other stable isotopes to infer the geographic origin of individuals.  相似文献   
833.
North American Double-crested Cormorant (Phalacrocorax auritus) populations have increased greatly. Both breeding and overwintering ground factors have likely contributed to these increases. However, demonstrating how overwintering conditions may affect breeding birds has not been possible because of the difficulty in linking breeding birds to their wintering grounds. Here, we demonstrate the utility of stable sulfur isotopes to elucidate overwintering habitat use by cormorants breeding on Lake Erie. Sulfur isotopes in feathers grown on overwintering grounds provided insights into the degree to which birds used freshwater vs. marine environments. The proportion of birds utilizing freshwater habitats increased through time. This change may have reflected increases in freshwater aquaculture (i.e., catfish) in the U.S. south. Examination of body condition in birds returning to breed on Lake Erie indicated that those individuals that solely used marine habitats for at least a portion of the overwintering period were in poorer condition than birds using freshwater. Enhanced foraging opportunities at aquaculture facilities may improve the fitness of individuals that have returned to breed after overwintering at such locations. This study is the first to demonstrate a linkage between overwinter habitat use and breeding ground parameters in Double-crested Cormorants. These results underscore that factors throughout the Mississippi flyway are likely acting together to regulate cormorant populations.  相似文献   
834.
Terrestrial plant community responses to herbivory depend on resource availability, but the separate influences of different resources are difficult to study because they often correlate across natural environmental gradients. We studied the effects of excluding ungulate herbivores on plant species richness and composition, as well as available soil nitrogen (N) and phosphorus (P), across eight grassland sites in Serengeti National Park (SNP), Tanzania. These sites varied independently in rainfall and available soil N and P. Excluding herbivores decreased plant species richness at all sites and by an average of 5.4 species across all plots. Although plant species richness was a unimodal function of rainfall in both grazed and ungrazed plots, fences caused a greater decrease in plant species richness at sites of intermediate rainfall compared to sites of high or low rainfall. In terms of the relative or proportional decreases in plant species richness, excluding herbivores caused the strongest relative decreases at lower rainfall and where exclusion of herbivores increased available soil P. Herbivore exclusion increased among-plot heterogeneity in species composition but decreased coexistence of congeneric grasses. Compositional similarity between grazed and ungrazed treatments decreased with increasing rainfall due to greater forb richness in exclosures and greater sedge richness outside exclosures and was not related to effects of excluding herbivores on soil nutrients. Our results show that plant resources, especially water and P, appear to modulate the effects of herbivores on tropical grassland plant diversity and composition. We show that herbivore effects on soil P may be an important and previously unappreciated mechanism by which herbivores influence plant diversity, at least in tropical grasslands.  相似文献   
835.
We assessed the effects of crude oil and drill cuttings on sediment oxygen demand (SOD) of marine benthic communities from Arctic (Barents Sea) and temperate (Oslofjord) areas of the Norwegian continental shelf. Field-collected cores in both areas were subjected to three different treatments: two concentrations of hydrocarbon-contaminated sediments, and drill cuttings (DC). Cores were incubated for 21 days at 5°C (Barents Sea) and at 10°C (Oslofjord) during which SOD was measured five times. We observed significantly higher SOD in the high oil concentration (HOC) and DC treatments compared to control cores from the Arctic, but not in the temperate Oslofjord. No difference was observed between the low oil concentration (LOC) and control at either location. The clear differences in the response of Arctic benthic communities to petroleum compounds compared to temperate benthic communities is likely related to differences in community structure, sensitivity of individual taxa to petroleum-related compounds and different contamination history of the two study areas.  相似文献   
836.
本文摘要介绍了液相色谱/离子阱质谱和液相/飞行时间质谱对橄榄油中特丁津的定性定量分析.详细介绍了样品处理,包括液-液萃取和以氨基硅胶为基质分散的固相萃取法.样品的净化采用Florisil硅土小柱,用乙腈洗脱溶质.液相色谱/离子阱质谱的MS/MS模式采集特征离子m/z174.而利用液相/飞行时间质谱进行精确质量数分析([M+H]^+,m/z230),同时得到碎片的精确质量数和特征同位素分布.对于飞行时间质谱测得的质量精度小于ppm.此方法具有高灵敏度、线性好及精度高的优点.液相/离子阱质谱和飞行时间质谱可以作为橄榄油中特丁津的常规方法.[编者按]  相似文献   
837.
苯并咪唑类化合物(benzimidazoles)如涕必灵(thiabendazole)常作为杀菌剂普遍用在瓜果及农作物上.用液相色谱法分析这些物质比较困难:例如涕必灵,在硅胶基质的色谱柱上会发生严重的拖尾现象,酸性条件下尤为明显。涕必灵和多菌灵(carbendazim)在pH10的情况下使用XTerra MS C18色谱柱会得到较好的峰形,但在较高的pH值下,其它类型杀菌剂或杀虫剂可能不稳定,故难以用适合这些碱性杀菌剂的高pH值条件进行同时分析.  相似文献   
838.
<正>Mercury is a global pollutant due to its widespread use,emission,and long-range transport(Blum,2013;Pacyna et al.,2010).It is considered a priority pollutant due to its neurological toxicity,persistence,and bioaccumulation(Pacyna et al.,2010;Sharma et al.,2015).Mercury pollution can occur when products that contain mercury are improperly disposed of and mercury is released into the air,water,and soil(Zhang and Wong,2007).An estimated 22%of the annual world usage of mercury is in electrical equipment such as batteries,thermometers,and discharge lamps,and electronic devices such as monitors and  相似文献   
839.
Kinetics of phenol and chlorophenol utilization by Acinetobacter species   总被引:9,自引:0,他引:9  
Hao OJ  Kim MH  Seagren EA  Kim H 《Chemosphere》2002,46(6):797-807
Although microbial transformations via cometabolism have been widely observed, the few available kinetic models of cometabolism have not adequately addressed the case of inhibition from both the growth and nongrowth substrates. The present study investigated the degradation kinetics of self-inhibitory growth (phenol) and nongrowth (4-chlorophenol, 4-CP) substrates, present individually and in combination. Specifically, batch experiments were performed using an Acinetobacter isolate growing on phenol alone and with 4-CP present. In addition, batch experiments were also performed to evaluate the transformation of 4-CP by resting, phenol-induced Acinetobacter cultures. The Haldane kinetic model adequately predicted the biodegradation of phenol alone, although a slight discrepancy was noted in cases of higher initial phenol concentrations. Similarly, a Haldane model for substrate utilization was also able to describe the trends in 4-CP transformation by the resting cell cultures. The 4-CP transformation by the Acinetobacter species growing on phenol was modeled using a competitive kinetic model of cometabolism, which included growth and nongrowth substrate inhibition and cross-inhibition terms. Excellent agreement was obtained between the model predictions using experimentally estimated parameter values and the experimental data for the synchronous disappearance of phenol and 4-CP.  相似文献   
840.
Passive air sampling theory for semivolatile organic compounds   总被引:2,自引:0,他引:2  
The mathematical modelling underlying passive air sampling theory can be based on mass transfer coefficients or rate constants. Generally, these models have not been inter-related. Starting with basic models, the exchange of chemicals between the gaseous phase and the sampler is developed using mass transfer coefficients and rate constants. Importantly, the inter-relationships between the approaches are demonstrated by relating uptake rate constants and loss rate constants to mass transfer coefficients when either sampler-side or air-side resistance is dominating chemical exchange. The influence of sampler area and sampler volume on chemical exchange is discussed in general terms and as they relate to frequently used parameters such as sampling rates and time to equilibrium. Where air-side or sampler-side resistance dominates, an increase in the surface area of the sampler will increase sampling rates. Sampling rates are not related to the sampler/air partition coefficient (K(SV)) when air-side resistance dominates and increase with K(SV) when sampler-side resistance dominates.  相似文献   
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