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1.
Dick B 《Disasters》1985,9(4):259-269
Although there have been a number of recent developments in our understanding of refugee health problems that have influenced policies and action, the effects of refugees on the health status and services of host communities remain relatively neglected. This article sets out to explain why this is an important issue with implications for policy, planning surveillance and evaluation, training and research.
The first sections outline some of the problems facing host governments and communities in Africa and discuss the changing rhetoric between the first and second International Conferences for Assistance to Refugees in Africa. A number of possible ways in which refugees could affect the individual, agent and environmental causes of disease are considered, as are the characteristics of the refugees, the host communities and the response which may all modify this impact.
Policy implications of the impact of the refugees, both negative and positive, are discussed, and detailed consideration is given to the pros and cons of integrated and parallel approaches to health care provision. The need to monitor carefully the health status and services of host communities is emphasized and recommendations are made for this and other essential developments relating to training and research.  相似文献   
2.
综合评分指标体系在环境优先污染物筛选中的应用   总被引:3,自引:0,他引:3  
介绍了一种用于环境优先污染物筛选的综合评分指标体系,并以上海市石化行业废气优先污染物的筛选为实例说明。  相似文献   
3.
Myrmecophily provides various examples of how social structures can be overcome to exploit vast and well-protected resources. Ant nest beetles (Paussinae) are particularly well suited for ecological and evolutionary considerations in the context of association with ants because life habits within the subfamily range from free-living and predatory in basal taxa to obligatory myrmecophily in derived Paussini. Adult Paussini are accepted in the ant society, although parasitising the colony by preying on ant brood. Host species mainly belong to the ant families Myrmicinae and Formicinae, but at least several paussine genera are not host-specific. Morphological adaptations, such as special glands and associated tufts of hair (trichomes), characterise Paussini as typical myrmecophiles and lead to two different strategical types of body shape: while certain Paussini rely on the protective type with less exposed extremities, other genera access ant colonies using glandular secretions and trichomes (symphile type). We compare these adaptations with other taxonomic groups of insects by joining contemporary research and early sources and discuss the possibility of an attracting or appeasing effect of the secretion. Species that are ignored by their host ants might use chemical mimicry instead. Furthermore, vibrational signals may contribute to ant–beetle communication, and chemical signals have proven to play a role in host finding. The powerful defense chemistry of paussines as “bombardier beetles” is not used in contact with host ants. We attempt to trace the evolution of myrmecophily in paussines by reviewing important aspects of the association between paussine beetles and ants, i.e. morphological and potential chemical adaptations, life cycle, host specificity, alimentation, parasitism and sound production.
Stefanie F. GeiselhardtEmail:
  相似文献   
4.
企业安全管理体系标准模式的比较研究   总被引:7,自引:4,他引:3  
采用对比分析法和实证分析法,对当前国内外流行的企业安全管理体系标准模式及其评价方法进行比较研究,旨在把握诸多标准模式的原则、路径、结构、方法和共性特征及其可以发挥的具体优点,将研究的标准模式的评价方法归纳为两大类即体系认证审核法和综合考评打分法,并对两类评价方法的优缺点进行剖析。体系认证审核法的优点是过程方法、符合性及抽样,考评打分法则提供了安全绩效准则。对吸收融合两类评价方法的优点形成综合性评价方法的途径和方式进行了探讨,为企业建立有效、适用的安全管理体系提供了依据。  相似文献   
5.
The spatiotemporal structure of the muskrat population has been studied by means of the prenatal radioactive marking of juveniles with 45 Ca and their subsequent recapture in the test area. The muskrat population is characterized by a cyclic type of spatial structure, with seasonal transition from a mosaic type of settling to a diffuse type and, after the breeding season, vice versa.  相似文献   
6.
为保障信号交叉口的正常交通秩序,充分遏制机动车未按规定导向车道行驶行为,亟需探究该行为的影响因素及干预方法。以北京市内4个信号交叉口处共35 h的1 666条监控视频数据为基础,对未按规定导向车道行驶行为进行定义并将其分为9类,分别对频率较高的5类未按规定导向车道行驶行为构建二元Logit模型,以确定其关键影响因素,并据此提出干预方法。结果表明,排队车辆数、大车比例、时段、车流量、照明条件等因素会不同程度地影响5类未按规定导向车道行驶行为的发生概率,其中排队车辆数及时间因素影响最为显著。在此基础上,从交通工程设施及驾驶人安全意识角度,提出优化交叉口渠化设计及信号配时、采用智能标线、强化监管力度及完善交通管控设施、加强驾驶人安全教育4种未按规定导向车道行驶行为干预方法。  相似文献   
7.
The host choice and sex allocation decisions of a foraging female parasitoid will have an enormous influence on the life-history characteristics of her offspring. The pteromalid Pachycrepoideus vindemiae is a generalist idiobiont pupal parasitoid of many species of cyclorrhaphous Diptera. Wasps reared in Musca domestica were larger, had higher attack rates and greater male mating success than those reared in Drosophila melanogaster. In no-choice situations, na?ve female P. vindemiae took significantly less time to accept hosts conspecific with their natal host. Parasitoids that emerged from M. domestica pupae spent similar amounts of time ovipositing in both D. melanogaster and M. domestica. Those parasitoids that had emerged from D. melanogaster spent significantly longer attacking M. domestica pupae. The host choice behaviour of female P. vindemiae was influenced by an interaction between natal host and experience. Female P. vindemiae reared in M. domestica only showed a preference among hosts when allowed to gain experience attacking M. domestica, preferentially attacking that species. Similarly, female parasitoids reared on D. melanogaster only showed a preference among hosts when allowed to gain experience attacking D. melanogaster, again preferentially attacking that species. Wasp natal host also influenced sex allocation behaviour. While wasps from both hosts oviposited more females in the larger host, M. domestica, wasps that emerged from M. domestica had significantly more male-biased offspring sex ratios. These results indicate the importance of learning and natal host size in determining P. vindemiae attack rates, mating success, host preference and sex allocation behaviour, all critical components of parasitoid fitness. Electronic Publication  相似文献   
8.
Gregarious behaviour (i.e. living in groups in contrast to a solitary life) is commonly observed in mammals, but rarely documented in amphibians. Environmental features and/or animal mutual attractions can promote the formation of aggregations that may both reduce the risks of dehydration and predation and increase mate access and fitness. Luschan’s salamander (Mertensiella luschani) lives in permanently arid Mediterranean environments; individuals shelter in cracks and crevices and leave only during favourable periods. In this study we examined the role of chemical tracks, in self and conspecific recognition (i.e. gregarious/solitary behaviour), on the social structure of this species. Our results show that juveniles and adults of both sexes use chemical scents deposited on substrate to relocate their shelter. In contrast to numerous other salamander species, Luschan’s salamanders also use social information, conveyed by conspecific scents, to identify a safe shelter. Furthermore, this scent marking does not play a role in sexual attraction but allows sex discrimination. This species exhibits gregarious behaviour (i.e. conspecific attraction) as a possible adaptation to dry environments. We discuss both ultimate and proximate factors in the evolution from a solitary to a gregarious life.  相似文献   
9.
Both phytophagous and parasitic insects deposit oviposition-marking pheromones (OMPs) following oviposition that function to inform conspecifics of a previously utilized host of reduced suitability. The blueberry maggot fly, Rhagoletis mendax Curran (Diptera: Tephritidae), deposits eggs individually into blueberries and then marks the fruit surface with an OMP which reduces acceptance of fruit for oviposition by conspecifics. Diachasma alloeum (Muesebeck) (Hymenoptera: Braconidae) is a parasitic wasp attacking larval R. mendax which also deposits an OMP, signaling conspecifics of a wasp-occupied host. Behavioral studies were conducted testing the hypothesis that the OMP of the parasitic wasp modifies the oviposition behavior of its host fly. In this study, we show that the OMP of D. alloeum is recognized by R. mendax, and female flies will reject wasp-marked fruit for oviposition. Thus, we present a rare demonstration of pheromonal recognition between animals occupying different taxonomic orders and trophic levels. This chemical eavesdropping may enhance the ability of the fly to avoid fruit unsuitable for larval development.  相似文献   
10.
The host size model, an adaptive model for maternal manipulation of offspring sex ratio, was examined for the parasitoid wasp Spalangia endius. In a Florida strain, as the model predicts, daughters emerged from larger hosts than sons, but only when mothers received both small and large hosts simultaneously. The pattern appeared to result from the mother's ovipositional choice and not from differential mortality of the sexes during development. If sex ratio manipulation is adaptive in the Florida strain, it appears to be through a benefit to daughters of developing on large hosts rather than through a benefit to sons of developing on small hosts. Both female and male parasitoids were larger when they developed on larger hosts. For females, developing on a larger host (1) increased offspring production, except for the largest hosts, (2) increased longevity, (3) lengthened development, and (4) had no effect on wing loading. For males, development on a larger host had no effect on any measure of male fitness – mating success, longevity, development duration, or wing loading. In contrast, a strain from India showed no difference in the size of hosts from which daughters versus sons emerged, although both female and male parasitoids were larger when they developed on larger hosts. These results together with previous studies of Spalangia reveal no consistent connection between host-size-dependent sex ratio and host-size-dependent parasitoid size among strains of S. endius or among species of Spalangia. Received: 28 October 1998 / Received in revised form: 20 May 1999 / Accepted: 30 May 1999  相似文献   
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