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171.
我国现行职业病诊断鉴定法律制度存在较大缺陷,使得受害劳动者维权乏力,笔者在分析探讨职业病诊断鉴定制度所存相关问题的基础上,有针对性地提出改革完善的相应建议,同时对新出台的《职业病防治法修正案(草案)》的有关修订内容做出评议。 相似文献
172.
Chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), is widespread among amphibians in northeastern North America. It is unknown, however, whether Bd has the potential to cause extensive amphibian mortalities in northeastern North America as have occurred elsewhere. In the laboratory, we exposed seven common northeastern North American amphibian species to Bd to assess the likelihood of population-level effects from the disease. We exposed larval wood frogs (Lithobates sylvaticus) and postmetamorphic frogs of six other species to two different strains of Bd, a northeastern strain (JEL404) and a strain that caused die-offs of amphibians in Panama (JEL423), under ideal in vitro growth conditions for Bd. Exposed American toads (Anaxyrus americanus) all died; thus, this species may be the most likely to die from Bd-caused disease in the wild. Both Bd strains were associated with mortalities of wood frogs, although half the metamorphs survived. The Bd strain from Panama killed metamorphic green frogs (L. clamitans), whereas the northeastern strain did not, which means novel strains of Bd may lead to death even when local strains may not. No mortality was observed in four species (bullfrogs [L. catesbeianus], northern leopard frogs [L. pipiens], spring peepers [Pseudacris crucifer], and blue-spotted salamanders [Ambystoma laterale]) and in some individuals of green frogs and wood frogs that we exposed. This finding suggests these six species may be Bd vectors. Our results show that systematic exposures of amphibian species to Bd in the laboratory may be a good first step in the identification of species susceptible to Bd-caused declines and in directing regional conservation efforts aimed at susceptible species. 相似文献
173.
Intraspecific crop diversification is thought to be a possible solution to the disease susceptibility of monocultured crops. We modelled the stratified dispersal of an airborne pathogen population in order to identify the spatial patterns of cultivar mixtures that could slow epidemic spread driven by dual dispersal mechanisms acting over both short and long distances. We developed a model to simulate the propagation of a fungal disease in a 2D field, including a reaction-diffusion model for short-distance disease dispersal, and a stochastic model for long-distance dispersal. The model was fitted to data for the spatio-temporal spread of faba bean rust (caused by Uromyces viciae-fabae) through a discontinuous field. The model was used to compare the effectiveness of eight different planting patterns of cultivar mixtures against a disease spread by short-distance and stratified dispersal. Our combined modelling approach provides a reasonably good fit with the observed data for the spread of faba bean rust. Similar predictive power could be expected for the management of resource-mediated invasions by other airborne fungi. If a disease spreads by short-distance dispersal, random mixtures can be used to slow the epidemic spread, since their spatial irregularity creates a natural barrier to the progression of a smooth epidemic wave. In the context of stratified dispersal, heterogeneous patterns should be used that include a minimum distance between susceptible units, which decreases the probability of infection by long-distance spore dispersal. We provide a simple framework for modelling the stratified dispersal of disease in a diversified crop. The model suggests that the spatial arrangement of components in cultivar mixtures has to accord with the dispersal characteristics of the pathogen in order to increase the efficiency of diversification strategies in agro-ecosystems and forestry. It can be applied in low input agriculture to manage pathogen invasion by intercropping and cultivar mixtures, and to design sustainable systems of land use. 相似文献
174.
VA菌根菌(VAM菌)与植物土传病害的关系受到广泛的研究。本文从VAM菌对植物抗病性的影响及其可能性机理和相应的农业管理措施等方面进行了介绍和评述,同时提出问题和展望,并强调该方面的研究在可持续发展农业中的重要性。 相似文献
175.
为了探讨室内空气污染与慢性阻塞性肺部疾病(COPD)的关系,对云南省宣威县使用不同生活燃料、年龄≥40岁的农民10892人进行了COPD及其症状的现患率调查,同时测定了调查对象的最大呼气流速(PEF).结果表明,不同燃料造成的室内空气污染对COPD及其症状和最大呼气流速的作用顺序依次为有烟煤>无烟煤>柴.在调整了年龄、性别、吸烟和改灶年限等因素后发现,使用有烟煤和使用无烟煤的人群患COPD的危险性分别是使用柴的4.63倍和1.55倍.改灶年限越长,COPD及其症状的现患率越低,最大呼气流速越高.室内燃煤空气污染是影响宣威慢性阻塞性肺部疾病(COPD)的主要危险因素,改炉改灶对控制COPD及其症状的现患水平,改善肺功能具有积极的作用. 相似文献
176.
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178.
探讨兰州市空气污染对不同性别和年龄的儿童呼吸疾病就诊人数的影响以及季节性变化.通过收集2013~2017年兰州市空气污染物PM2.5、PM10、SO2、NO2、CO和O38h浓度数据、气象数据及3家三甲医院儿童呼吸疾病门诊资料,采用广义相加模型(GAM)控制星期几效应、气象因素、假期效应等混杂因素,分析空气污染物浓度与儿童呼吸系统疾病日门诊量的关系及滞后效应.研究期间,兰州市3家三甲医院儿童呼吸系统疾病日门诊量平均为387人次,范围1~1413人次.单污染物模型结果显示,PM2.5、NO2、SO2、CO均在累积滞后一天(lag01)时效应量达到最大值,其浓度每增加10μg/m3(CO单位为1mg/m3),儿童呼吸系统疾病就诊人次的超额危险度(ER)及95%可信区间(95% CI)分别为0.245%(95% CI:0.127%~0.363%),0.568%(95% CI:0.327%~0.808%),1.661%(95% CI:1.022%~2.302%),2.245%(95% CI:1.610%~2.883%);PM10和O38h在各滞后天数均无统计学意义.对不同性别、年龄、季节分析发现,性别分层中PM2.5对女童的影响略高于男童,NO2、SO2和CO的影响男童略高于女童;年龄分层发现PM2.5、NO2和CO的影响6~14岁组大于0~5岁组,SO2的影响0~5岁组大于6~14岁组;季节分层中PM2.5、NO2、SO2和CO对门诊量的影响只在冬季有意义,PM10和O38h在各个季节均无意义.双污染物模型结果显示,分别调整其他5种污染物后,PM10和O38h对儿童呼吸系统疾病门诊量的增加均无统计学意义;调整PM10和O38h后,其他污染物呼吸系统疾病门诊量的增加均有统计学意义.兰州空气污染物(PM2.5、NO2、SO2、CO)与呼吸系统疾病门诊量密切相关,并且SO2和CO浓度增加更易增加儿童呼吸系统疾病的发病风险.性别、年龄和季节对空气污染物和呼吸系统疾病门诊就诊人次的关系有影响. 相似文献
179.
Differences in sensitivity to the fungal pathogen Batrachochytrium dendrobatidis among amphibian populations
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Paul W. Bradley Stephanie S. Gervasi Jessica Hua Rickey D. Cothran Rick A. Relyea Deanna H. Olson Andrew R. Blaustein 《Conservation biology》2015,29(5):1347-1356
Contributing to the worldwide biodiversity crisis are emerging infectious diseases, which can lead to extirpations and extinctions of hosts. For example, the infectious fungal pathogen Batrachochytrium dendrobatidis (Bd) is associated with worldwide amphibian population declines and extinctions. Sensitivity to Bd varies with species, season, and life stage. However, there is little information on whether sensitivity to Bd differs among populations, which is essential for understanding Bd‐infection dynamics and for formulating conservation strategies. We experimentally investigated intraspecific differences in host sensitivity to Bd across 10 populations of wood frogs (Lithobates sylvaticus) raised from eggs to metamorphosis. We exposed the post‐metamorphic wood frogs to Bd and monitored survival for 30 days under controlled laboratory conditions. Populations differed in overall survival and mortality rate. Infection load also differed among populations but was not correlated with population differences in risk of mortality. Such population‐level variation in sensitivity to Bd may result in reservoir populations that may be a source for the transmission of Bd to other sensitive populations or species. Alternatively, remnant populations that are less sensitive to Bd could serve as sources for recolonization after epidemic events. 相似文献
180.
Effects of white‐nose syndrome on regional population patterns of 3 hibernating bat species
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Hibernating bats have undergone severe recent declines across the eastern United States, but the cause of these regional‐scale declines has not been systematically evaluated. We assessed the influence of white‐nose syndrome (an emerging bat disease caused by the fungus Pseudogymnoascus destructans, formerly Geomyces destructans) on large‐scale, long‐term population patterns in the little brown myotis (Myotis lucifugus), the northern myotis (Myotis septentrionalis), and the tricolored bat (Perimyotis subflavus). We modeled population trajectories for each species on the basis of an extensive data set of winter hibernacula counts of more than 1 million individual bats from a 4‐state region over 13 years and with data on locations of hibernacula and first detections of white‐nose syndrome at each hibernaculum. We used generalized additive mixed models to determine population change relative to expectations, that is, how population trajectories differed with a colony's infection status, how trajectories differed with distance from the point of introduction of white‐nose syndrome, and whether declines were concordant with first local observation of the disease. Population trajectories in all species met at least one of the 3 expectations, but none met all 3. Our results suggest, therefore, that white‐nose syndrome has affected regional populations differently than was previously understood and has not been the sole cause of declines. Specifically, our results suggest that in some areas and species, threats other than white‐nose syndrome are also contributing to population declines, declines linked to white‐nose syndrome have spread across large geographic areas with unexpected speed, and the disease or other threats led to declines in bat populations for years prior to disease detection. Effective conservation will require further research to mitigate impacts of white‐nose syndrome, renewed attention to other threats to bats, and improved surveillance efforts to ensure early detection of white‐nose syndrome. 相似文献