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561.
基于职业健康内涵和统计学原理,提出职业健康统计学的概念,并分析其学科基础,比较职业健康统计学实践应用的各种统计方法;从行业、工种、职业危害因素、职业病发展动态及等级结构、职业健康损失等方面构建职业健康统计学分支体系;分析职业健康统计绝对指标、相对指标。  相似文献   
562.
水处理活性炭吸附性能指标的表征与应用   总被引:11,自引:0,他引:11       下载免费PDF全文
使用碘值、苯酚值、甲基蓝值和丹宁酸值4种吸附容量性能指标组成水处理活性炭选型技术.经BET测试验证,碘值可以体现活性炭中孔径略大于1.0nm微孔的发达程度,表征比表面积大小;甲基蓝值则代表孔径大于1.5nm的微孔和中孔发达程度;而丹宁酸值代表直径大于2.8nm左右的中孔数量;苯酚值体现活性炭表面化学信息,可表征活性炭对于小分子芳环类和极性有机物的吸附能力.硝基苯、甲基叔丁基醚(MTBE)、双酚A(BPA)、腐殖酸以及焦化厂二级生化出水的吸附实验结果均验证了该技术作为水处理活性炭实用选型方法的有效性.  相似文献   
563.
Background, Aim and Scope Analysis of the morphological, geological and environmental characteristics of the Sarno River basin has shown the present degraded condition of the area. Over the past thirty years, the supply of untreated effluent of domestic, agricultural and industrial origin has ensured the presence of high concentrations of pollutants, including heavy metals. The geological context of the catchment area has played a major part in determining the current ecological conditions and public health problems: while human activity has modified the landscape, the natural order has indirectly contributed to increasing the environmental impact. Results and Discussion The health situation is precarious as the basin's inhabitants feed on agricultural and animal products, and use polluted water directly or indirectly. The hazard of contracting degenerative illnesses of the digestive or respiratory apparatus, bacterial infections or some neoplasia has gradually increased, especially in the last five years. Moreover, polluted basin waters flowing into the Bay of Naples increase sea water contamination, thereby damaging tourism, public health and degrading the local littoral quality. Conclusion The overview presented shows how the environmental state of the Sarno River basin gives considerable cause for concern. The basin's complex geomorphologic setting has a direct bearing on local environmental and health conditions. The analysis of the available data demonstrates how the physical aspects of the area are closely linked to the diffusion and concentration of the pollutants, and how the latter ones have a large influence on the hygienic-sanitary conditions of the local population. Recommendation and Perspective Specific interventions need to be undertaken to monitor and improve the chemical, physical and microbiological conditions of water and sediments, especially in light of the geomorphological vulnerability of the river basin.  相似文献   
564.
Ornithine transcarbamylase (OTC) deficiency is an X-linked disorder of the urea cycle mapped to chromosome Xp21.1. Here, we show that apparent segregation of null alleles at the OTC locus and flanking polymorphic loci mimicked false maternity or false paternity in three affected families. Based on these observations, we suggest giving consideration to gene deletion when dealing with segregation of null alleles in OTC deficiency.  相似文献   
565.
Abstract:  In the wet tropics of Queensland, Australia, eight species of stream-dwelling frogs have experienced population declines. Some declines were associated with an emerging infectious disease of amphibians (chytridiomycosis) caused by the fungus Batrachochytrium dendrobatidis. We examined the spatial and temporal pattern of infection prevalence in a sample of frog populations. Infected adults and tadpoles of all species were found, and infections occurred at every site. Infection prevalence varied among species and was always < 10.0% in adults but ranged from 0.75 to 76.0% in tadpoles. In this system tadpoles and adults of some species may act as disease reservoirs, experiencing avirulent infections, whereas other hosts (declining species) experience virulent infections. Infection prevalence was higher during the cool, dry winter season (May to September) and at high elevations (600–800 m), suggesting regulation by environmental conditions, including temperature and precipitation. We found no relationships between infection prevalence and mean body condition, fluctuating asymmetry of hind limbs, population density, or the presence of metamorphosing tadpoles and juvenile frogs. Although it is not certain whether chytridiomycosis was responsible for past frog population declines in the wet tropics of Queensland, the pathogen is now endemic. Our data indicate that at the landscape level, environmental conditions have strong effects on host-pathogen dynamics. These effects interact with species-specific behavior or immune function and may be important underlying determinants of chytridiomycosis epizootics and emergence.  相似文献   
566.
Assessing the scope and severity of threats is necessary for evaluating impacts on populations to inform conservation planning. Quantitative threat assessment often requires monitoring programs that provide reliable data over relevant spatial and temporal scales, yet such programs can be difficult to justify until there is an apparent stressor. Leveraging efforts of wildlife management agencies to record winter counts of hibernating bats, we collated data for 5 species from over 200 sites across 27 U.S. states and 2 Canadian provinces from 1995 to 2018 to determine the impact of white-nose syndrome (WNS), a deadly disease of hibernating bats. We estimated declines of winter counts of bat colonies at sites where the invasive fungus that causes WNS (Pseudogymnoascus destructans) had been detected to assess the threat impact of WNS. Three species undergoing species status assessment by the U.S. Fish and Wildlife Service (Myotis septentrionalis, Myotis lucifugus, and Perimyotis subflavus) declined by more than 90%, which warrants classifying the severity of the WNS threat as extreme based on criteria used by NatureServe. The scope of the WNS threat as defined by NatureServe criteria was large (36% of Myotis lucifugus range) to pervasive (79% of Myotis septentrionalis range) for these species. Declines for 2 other species (Myotis sodalis and Eptesicus fuscus) were less severe but still qualified as moderate to serious based on NatureServe criteria. Data-sharing across jurisdictions provided a comprehensive evaluation of scope and severity of the threat of WNS and indicated regional differences that can inform response efforts at international, national, and state or provincial jurisdictions. We assessed the threat impact of an emerging infectious disease by uniting monitoring efforts across jurisdictional boundaries and demonstrated the importance of coordinated monitoring programs, such as the North American Bat Monitoring Program (NABat), for data-driven conservation assessments and planning.  相似文献   
567.
土壤中硒的甲基化可能会导致硒的挥发,加剧土壤硒的流失,而农田土壤硒的缺乏会造成农作物中硒含量偏低.施用硫肥是保障作物增产、增收的一种重要农艺措施,外源硫输入对土壤硒的含量可能产生重要的调控作用.本研究模拟稻田淹水环境,通过添加典型有机硫(甲硫氨酸)和无机硫(硫酸钠),测定硒的挥发量以及土壤中残留的硒含量,以揭示外源硫输...  相似文献   
568.
Pant KP 《Ambio》2012,41(3):271-283
Biomass fuels are used by the majority of resource poor households in low-income countries. Though biomass fuels, such as dung-briquette and firewood are apparently cheaper than the modern fuels indoor pollution from burning biomass fuels incurs high health costs. But, the health costs of these conventional fuels, mostly being indirect, are poorly understood. To address this gap, this study develops probit regression models using survey data generated through interviews from households using either dung-briquette or biogas as the primary source of fuel for cooking. The study investigates factors affecting the use of dung-briquette, assesses its impact on human health, and estimates the associated household health costs. Analysis suggests significant effects of dung-briquette on asthma and eye diseases. Despite of the perception of it being a cheap fuel, the annual health cost per household due to burning dung-briquette (US16.94) is 61.3 (US 16.94) is 61.3% higher than the annual cost of biogas (US 10.38), an alternative cleaner fuel for rural households. For reducing the use of dung-briquette and its indirect health costs, the study recommends three interventions: (1) educate women and aboriginal people, in particular, and make them aware of the benefits of switching to biogas; (2) facilitate tree planting in communal as well as private lands; and (3) create rural employment and income generation opportunities.  相似文献   
569.
The 2001 Foot and Mouth Diseaseoutbreak in the UK has had widespread adverseeffects – on the farming community, thetourist industry, millions of farm animals, theenvironment, and citizens' quality of life.This report summarizes the course of theepidemic and then questions the ethicalvalidity of the procedure chosen to eradicatethe disease, namely, the slaughter of millionsof animals. It is argued that the utilitarianbasis of the mass slaughter program isunjustified even in its own terms, and thatrespect for certain deontological principlesmerits increased attention in public policy.The long-term interests of UK citizens, theviability of British farming, and theconservation of the countryside all depend onurgent, critical decisions that should beinformed by a broader conception of the role ofethics in agriculture.  相似文献   
570.
以石化企业在污水处理过程中产生的干化剩余污泥为原料,大同烟煤作辅助添加料,采用化学活化法制备污泥-烟煤基活性炭,探讨了活化剂(ZnCl2)用量、活化温度、活化时间等条件对所制备的活性炭性能的影响。以活性炭的碘吸附值为衡量指标,当污泥:烟煤(质量比)=1:1时获得制备污泥-烟煤活性炭的最佳工艺条件为:浸渍液为ZnCl2:原料(质量比)=2:1,活化温度550℃,活化时间30 min,在该条件下制备的活性炭的碘吸附值为990 mg·g-1,比表面积为836 m2·g-1,产率为46.6%。同时,以苯酚为目标污染物,考察了所制备的污泥-烟煤基活性炭对苯酚的去除效果,结果表明:污泥-烟煤基活性炭投加量为2.0 g·L-1时,4 h后达到吸附平衡,离子强度对吸附容量没有显著的影响,溶液pH在4~10范围内对苯酚有较好吸附,pH=6时苯酚吸附容量为138.9 mg·g-1。与同类吸附剂相比,制备的污泥-烟煤基活性炭可高效吸附水溶液中的苯酚。  相似文献   
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