排序方式: 共有36条查询结果,搜索用时 258 毫秒
21.
22.
Suzanne Model 《Ethnic and racial studies》2013,36(6):966-990
Using data drawn from the Samples of Anonymised Records (SARs) of the 1991 UK Census, this study uses multivariate analysis to examine the economic position of immigrants and their children on six dependent variables. The research finds that, net measurable individual characteristics, some non-white groups outperform native whites, several non-white groups outperform the foreign-born Irish, and Pakistanis are not uniquely disadvantaged. Native birth brings occupational improvement but does little to mitigate unemployment. In addition, on several outcomes, Indian males outrank Black Caribbean males, while Black Caribbean females outrank Indian females. The implications of these and other patterns are taken up in the article's concluding section. 相似文献
23.
目的:通过对医务人员在急诊手术中职业暴露的情况调查,了解急诊手术中标准预防现状,提出合理化建议和措施。方法:对2007年6月.2010年5月手术患者乙肝、丙肝、梅毒、艾滋病的阳性率进行比较,现场调查急诊手术中防护用品的使用情况。结果:手术患者乙肝、丙肝、梅毒、艾滋病的阳性率逐年上升,职业暴露的危险性越来越大;急诊手术中医务人员防护用品使用率的高低取决于血液、体液、分泌物的污染程度。结论:对医务人员要加强职业安全教育,强化标准预防,提高医务人员的整体防护水平,避免或减少职业暴露的危害,在救死扶伤的同时,保护好自身安全。 相似文献
24.
25.
Facundo R. Meroi Arcerito Karen Halpern Diego Balseiro Beatriz Waisfeld 《Comptes Rendus Palevol》2017,16(8):821-831
Major ecological transitions among evolutionary faunas are matters of continual debate. Our study analyses the timing and mode of replacement of Ibex I and II Trilobite Evolutionary Faunas (TEF) in Lower Ordovician successions of northwestern Argentina, with special emphasis on olenids and asaphids as key groups of the Ibex I and Ibex II faunas, respectively. We explore richness by using the sample rarefaction method, and occupancy based on a presence–absence dataset. The late Tremadocian 2 (Tr2) represents an inflexion point in richness and occupancy trajectories of asaphids and olenids. While olenids diminish their generic richness through time, asaphids became the richest family since the Tr3 predating the global trend recognized for the expansion of the Ibex II Fauna. Asaphids gained diversity at the expense of other trilobites as well, their rise in diversity lags behind the increase in occupancy suggesting a displacement scenario as the probable mode of replacement between the Ibex I and II TEFs. Apparently, the processes of replacement variate among regions across the globe, configuring a complex global mosaic of regional patterns. 相似文献
26.
Experimental data available in literature on changes in the carbon isotopic composition of biochemical fractions and metabolites isolated from plant biomass (Clusia minor) and photosynthesizing algae (Chlorella stigmatophora) under the action of environmental stress factors are reviewed and analyzed. Within the framework of previously suggested mechanism of carbon isotope fractionation in photosynthesis, all studied fractions and metabolites obtained from plants and photosynthesizing algae can be divided into two groups according to their carbon isotope composition. The first group includes the fractions and metabolite pools that contain carbon stored by cell during the carboxylase phase of Rubisco functioning. The second group consists of those formed primarily by the photorespiratory carbon flow, generated during the oxygenase phase of Rubisco functioning. The first group represents the assimilatory branch of photosynthesis and is enriched in 12C relative to carbon of biomass, whereas the second group represents the photorespiratory branch and is enriched in 13C. Under the action of environmental stress factors, such as incident light intensity, moisture availability, and salinity; the isotope composition of metabolites and fractions changes, which reflects variable contributions of the assimilatory and photorespiratory flows to the metabolite synthesis. These isotope shifts were used to study biochemical adaptation of plants to stress conditions and to elucidate the role of photorespiration in this adaptation. 相似文献
27.
Sheila Hicks 《Vegetation History and Archaeobotany》1992,1(2):75-86
The early vegetation history of the island Hailuoto, Finland, was investigated by means of pollen analysis. Pollen diagrams from three shallow peat profiles close to the postulated A.D. 1150 shoreline are interpreted with reference to modern pollen rain values, features indicative of occupation, routeways and cultivation being delimited. The differing settlement histories of the western and eastern parts of the present farmed area are distinguished and explained in terms of the changing coastline and availability of cultivable land. The historical evidence for changes in forest and farming conditions since the 16th century is also compared with the pollen evidence for the same period. Emphasis is placed on methodology and the development of investigation techniques applicable in sparsely settled boreal forest situations. 相似文献
28.
Taina Rantanen Sarianna Sipil? Harri Suominen 《European journal of applied physiology and occupational physiology》1993,66(6):514-517
The association between a history of heavy work and muscle strength was studied among 51 physically active women aged 66–85 years trained in sports and 41 women aged 70–81 years selected randomly from the population register. Maximal isometric muscle strength of hand grip, arm flexion, leg extension and trunk flexion and extension were measured using specially constructed dynamometers. The capacity of the abdominal muscles was evaluated by means of a sit-up test. The study included an interview dealing with the subjects' histories of heavy manual employment. The mean histories of heavy work for the trained and untrained women were 24 and 36 years, respectively. The trained women showed significantly greater maximal isometric muscle strength and abdominal muscle capacity than the untrained women. Among the trained women there was no correlation between the amount of heavy work and muscle performance. Among the untrained women the amount of heavy work correlated positively with maximal isometric trunk extension strength. The results would suggest that among elderly women, whether physically active or not, a history of heavy work has no systematic association with muscle strength. 相似文献
29.
Many databases exist with which it is possible to study the relationship between health events and various potential risk factors. Among these databases, some have variables that naturally form a hierarchical tree structure, such as pharmaceutical drugs and occupations. It is of great interest to use such databases for surveillance purposes in order to detect unsuspected relationships to disease risk. We propose a tree-based scan statistic, by which the surveillance can be conducted with a minimum of prior assumptions about the group of occupations/drugs that increase risk, and which adjusts for the multiple testing inherent in the many potential combinations. The method is illustrated using data from the National Center for Health Statistics Multiple Cause of Death Database, looking at the relationship between occupation and death from silicosis. 相似文献
30.
The objectives of this study were to explore individual differences associated with diverse reactions in cortisol secretion under different stress levels. This study was part of a larger project concerning working hours and health. Thirty-four white-collar workers participated under two different conditions; one work week with a high stress level (H) and one with a lower stress level (L) as measured through self-rated stress during workdays. Based on the morning cortisol concentration during a workday subjects were divided into two groups. One group consisted of subjects whose morning level of cortisol increased in response to the high-stress week, compared to their morning levels in the low-stress condition (Group 1). The other group consisted of subjects whose morning cortisol response was the opposite, with a lower level under the high stress condition (Group 2). Subjects wore actiwatches, completed a sleep diary, and rated their sleepiness and stress for one work week in each condition, i.e., high and low stress. Saliva samples for measures of cortisol were collected on a Wednesday. Group 2 reported higher workload, fatigue, and exhaustion during both weeks. Since there were no differences in perceived stress, neither within nor between groups, the data indicate that there are other factors influencing morning cortisol. The results suggest that one component modulating the cortisol response might be the level of exhaustion, probably related to work overload. Higher levels of stress in exhausted individuals might suppress morning cortisol levels. 相似文献