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1.
Internal armed conflicts have become more common and more physically destructive since the mid-20th century, with devastating consequences for health and development in low- and middle-income countries. This paper investigates the causal impacts of the long-term internal conflict on child health in Colombia, following an identification strategy based on the temporal and geographic variation of conflict intensity. We estimate the effect of different levels of conflict intensity on height-for-age (HAZ), weight-for-age (WAZ), and weight-for-height z-scores among children under five years old, and explore the underlying potential mechanisms, through maternal health behavior and health care utilization. We find a harmful effect of exposure to conflict violence in utero and in early childhood for HAZ and WAZ, in the full sample and even more strongly in the rural sample, yet these estimates are smaller than those found for shorter term conflicts. The underlying pathways appear to operate around the time of the pregnancy and birth (in the form of maternal alcohol use, use of antenatal care and skilled birth attendance), rather than during the post-birth period (via breastfeeding or vaccination), and the impacts accumulate over the childhood. The most adverse impacts of conflict violence on child health and utilization of maternal healthcare were observed in municipalities which suffered from intermittent presence of armed groups.  相似文献   

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Recent molecular phylogenies of the African elephants suggest that there is an evolutionary structure within Loxodonta africana. Some nuclear results ( Roca et al., 2001 ) support the separation of the forest African elephant subspecies L. a. cyclotis as a species distinct from the savannah elephant L. a. africana, on the basis of the recognition of both forming highly divergent (reciprocally monophyletic) clades. Conversely, a mitochondrial survey ( Eggert et al., 2002 ), while admitting a geographic partitioning of the genetic structure within African elephants, suggests retaining the status quo. They recognize three diagnosible entities (western, central and south‐eastern Africa) with non‐overlapping ranges within L. africana sensu lato. In order to address these conflicting views (historical fragmentation and speciation or isolation by distance, respectively), we have sequenced two datasets of 1961 bp (for 50 elephants) and about 3700 bp, respectively (for 20 elephants) of the mitochondrial DNA for both forms of elephants (cyclotis and africana). They span the cytochrome b gene, the control region and several RNAs. When compared with former mtDNA data, they provide the most comprehensive view of the African elephant phylogeny (78 mtDNA haplotypes, of which 44 are new) and provide the first insight into populations from the Democratic Republic of Congo. The genetic diversity of mtDNA was appraised and the stability of alternative phylogenetic trees was investigated. Our results are inconsistent with both those prior studies. They revealed two highly divergent molecular clades referred to as F and S, that do not conform to the morphological delineations of cyclotis and africana. A non‐negligible proportion of specimens of L. a. africana display haplotypes prevailing in forest elephant populations (clade F). The geographic distribution of clades and areas of their co‐occurrence support the hypothesis of incomplete isolation between forest and savannah African elephant populations, followed by recurrent interbreeding between the two forms. We state that the conclusions of prior studies resulted from insufficient character and/or geographic sampling. We conclude that there is no satisfying argument which can recognize two or more species of African elephants. We briefly comment on the meaning of such an attitude in a conservation viewpoint. © The Willi Hennig Society 2005.  相似文献   

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An important area of biology involves investigating the origins in animals of traits that are thought of as uniquely human. One way that humans appear unique is in the importance they attach to the dead bodies of other humans, particularly those of their close kin, and the rituals that they have developed for burying them. In contrast, most animals appear to show only limited interest in the carcasses or associated remains of dead individuals of their own species. African elephants (Loxodonta africana) are unusual in that they not only give dramatic reactions to the dead bodies of other elephants, but are also reported to systematically investigate elephant bones and tusks that they encounter, and it has sometimes been suggested that they visit the bones of relatives. Here, we use systematic presentations of object arrays to demonstrate that African elephants show higher levels of interest in elephant skulls and ivory than in natural objects or the skulls of other large terrestrial mammals. However, they do not appear to specifically select the skulls of their own relatives for investigation so that visits to dead relatives probably result from a more general attraction to elephant remains.  相似文献   

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The conflict between humans and elephants in the central African forests   总被引:2,自引:0,他引:2  
Elephants and humans each suffer from the presence of the other when they occupy the same forests. Farmers risk losing their crops to elephants, while elephants are displaced by settlements, agriculture, roads and development projects. Elephants have also been hunted for ivory. The ivory trade in the equatorial forests expanded in the nineteenth century as Europe prospered, and then again in the twentieth century as the Far East prospered. Forest elephant numbers were depleted each time.
Elephants are unpopular in the forest zone, and increasing human populations combined with the spread of democracy in central Africa pose a major threat to their future. If elephants are to be tolerated by villagers living in the equatorial forests, the costs they impose must be reduced and the benefits to the rural populace must be increased. A three-pronged strategy is suggested, involving land-use planning, measures to mitigate crop damage, and programmes to enhance the value of elephants. Elephants could be viewed as assets if their importance in the forest ecosystem were recognized, if they were domesticated for logging or transport, or if their presence was one of the factors which attracted tourists to the forest zone. However, management strategies based on hunting have the best chance of conserving elephants because of the importance of hunting in the culture of the forest people. Sport hunting for trophies may bring the greatest revenues. Community wildlife-management programmes, where village councils make the decisions, could prevent overexploitation. There are no simple answers, however, because one form of management may conflict with the goals of another.  相似文献   

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This study determined the abundance, density and population structure of the marula tree, Sclerocarya birrea, in three game reserves in South Africa, and assessed patterns and amounts of new and cumulative impact of elephants. Elephant feeding was very patchy so several attributes of individual trees, sampled transects and communities that might influence elephant herbivory were investigated. The incidence and type of elephant impact (bark, branch or stem breakage) were significantly related to tree diameter, but not to fruiting nor proximity to roads. At the transect level, elephant impact was influenced by density of marula trees, but was not influenced by proximity to roads, nor proportion of marula trees bearing fruits in the vicinity. At the community level, elephant impact was higher on reserves with higher total marula densities. Fourfold differences in elephant densities (0.08–0.30 elephants km?2) did not explain marula consumption: the percentage of trees with branch damage was similar across reserves and bark damage was inversely proportional to elephant density. Variation across reserves may reflect local and landscape‐level marula tree abundance, differences in alternative food plants and individual feeding habits. The recorded levels of impact appeared to be sustainable because mortality rates were low, affected trees often recovered, and small trees were not preferentially preyed upon.  相似文献   

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Ocular pentastomiasis is a rare infection caused by the larval stage of pentastomids, an unusual group of crustacean-related parasites. Zoonotic pentastomids have a distinct geographical distribution and utilize reptiles or canids as final hosts. Recently, an increasing number of human abdominal infections have been reported in Africa, where pentastomiasis is an emerging, though severely neglected, tropical disease. Here we describe four ocular infections caused by pentastomids from the Democratic Republic of the Congo. Two cases underwent surgery and an Armillifer grandis infection was detected by morphological and molecular approaches. Thus far, 15 other cases of ocular pentastomiasis have been reported worldwide. Twelve cases were caused by Armillifer sp., recorded almost exclusively in Africa, where such infections occur as a consequence of hunting and consuming snakes, their final hosts. Seven further cases were caused by Linguatula serrata, a cosmopolitan pentastomid whose final hosts are usually canids. Intraocular infections caused permanent visual damage in 69% and a total loss of vision in 31% of reported cases. In contrast, ocular adnexal cases had a benign clinical course. Further research is required to estimate the burden, therapeutic options and pathogenesis of this neglected disease.  相似文献   

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Globally, collisions between wildlife and aircraft are a serious threat to aviation safety. While reported collisions have increased in recent years, the impact of these collisions on air safety is rarely quantified. Here, we report all bat collisions (bat strikes) with civil aircraft known to have occurred in the Republic of Ireland over the 10-year interval, 2006–2015. Morphological and/or DNA identification techniques were used to identify chiropteran specimens to species level. In total, carcasses or remains from five bat strikes—three Leisler’s Nyctalus leisleri, one Soprano Pipistrelle Pipistrellus pygmaeus, and one Natterer’s Myotis nattereri—were recovered. The collisions are discussed in the context of (a) the rate of chiropteran strikes in relation to the number of civil aircraft movements and (b) possible damage caused to aircraft. Overall, however, bat strikes with aircraft appear to have a negligible effect on civil aircraft safety.  相似文献   

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Gambiense human African trypanosomiasis is a deadly disease that has been declining in incidence since the start of the Century, primarily due to increased screening, diagnosis and treatment of infected people. The main treatment regimen currently in use requires a lumbar puncture as part of the diagnostic process to determine disease stage and hospital admission for drug administration. Fexinidazole is a new oral treatment for stage 1 and non-severe stage 2 human African trypanosomiasis. The World Health Organization has recently incorporated fexinidazole into its treatment guidelines for human African trypanosomiasis. The treatment does not require hospital admission or a lumbar puncture for all patients, which is likely to ease access for patients; however, it does require concomitant food intake, which is likely to reduce adherence. Here, we use a mathematical model calibrated to case and screening data from Mushie territory, in the Democratic Republic of the Congo, to explore the potential negative impact of poor compliance to an oral treatment, and potential gains to be made from increases in the rate at which patients seek treatment. We find that reductions in compliance in treatment of stage 1 cases are projected to result in the largest increase in further transmission of the disease, with failing to cure stage 2 cases also posing a smaller concern. Reductions in compliance may be offset by increases in the rate at which cases are passively detected. Efforts should therefore be made to ensure good adherence for stage 1 patients to treatment with fexinidazole and to improve access to care.  相似文献   

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The water quality of the Lwiro River, Democratic Republic of Congo (DRC), Central Africa, was investigated on a monthly basis from December 1999–October 2000, at six stations along a hydraulic gradient from source to mouth, to evaluate the impact of land use on temperature, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD5), alkalinity and suspended solids. Upstream, where forests are conserved, minimal changes of physico-chemical parameters of water were observed. Downstream, DO was reduced, due to the increased organic matter content which increased the decomposition rate. BOD5 and suspended solids increased downstream. Greater changes were found near agricultural areas and villages. Wetlands appear to mitigate BOD5 and DO impacts.  相似文献   

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2020年1—12月,采用半结构式访查法、痕迹跟踪调查法和无人机跟踪调查法相结合的方法,对拟建西双版纳勐海县勐阿水库涉及区域的亚洲象种群结构、迁移路线等进行了调查,并采用样方法和3S技术对该区域亚洲象取食植物和栖息地适宜性进行了调查和分析,以探讨拟建勐阿水库可能对亚洲象迁移活动和人—象冲突的潜在影响。结果表明:(1)拟建勐阿水库区域活动的亚洲象小种群被称为澜沧江西部种群或西双版纳勐海—普洱澜沧种群,仅由19头亚洲象(10头雄性,9头雌性)组成,有2条亚洲象迁移路线穿越该区域;(2)在研究区域共统计到亚洲象取食植物12目19科32属33种,基本能满足该象群的取食需求;(3)海拔、坡度、植被隐蔽度及食物资源等生态因子的适宜性分析结果显示,大部分区域(包括占总面积14.61%的最适生境和占总面积82.05%的相对适宜生境)都能满足该亚洲象小种群的基本生活需求;(4)2条亚洲象迁移路线中的1条将因水库建设而阻断,迫使该象群改变原来的迁移路线;(5)水库淹没区的植被将被永久破坏,原本连片的适宜栖息地也将受到进一步切割和压缩影响;(6)当食物资源无法满足亚洲象生存需求时,它们可能会选择进入可在较短时间内获得大量食物的农耕区取食农作物和经济作物,随着人流、车流大量增加,亚洲象与人相遇的概率也会大幅度增加。分析认为,拟建勐阿水库将淹没1条迁移通道,对亚洲象迁移活动造成阻碍,迫使象群改变路线,还可能导致更为严重的人—象冲突。建议在水库工程设计和建设过程中采取有效的保护管理措施,减少工程项目对亚洲象种群及其栖息地的负面影响;水库建设和管理部门、林业和草原管理部门等应加强对亚洲象活动的监测和预警,避免亚洲象肇事造成人员伤亡和更大的经济损失。  相似文献   

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Taeniasis and cysticercosis are important but underreported parasitic zoonoses in the Lao People's Democratic Republic (Lao PDR). Reports of human and pig cysticercosis are rather limited and based largely on anecdotal evidence. To date, no structured surveys of disease prevalence or incidence have been reported. However, one unpublished pilot survey of pig cysticercosis in a slaughterhouse in northern Laos estimated prevalence to be 1.7%, without speciation of parasite cysts. Over the past 20 years, nine surveys of intestinal helminthic infection have been conducted; the prevalence of human taeniasis ranged from 0 to 14.0%. The study designs and sample sizes varied greatly, however a high degree of spatial and age variation in taeniasis prevalence was evident. These results are however inconclusive as the species of tapeworm infecting the people was not determined. To further our knowledge of taeniasis and cysticercosis in Lao PDR, structured community-based surveys in high-risk areas are required in combination with the use of sensitive and specific diagnostic tests capable of identifying the pork tapeworm, Taenia solium. This will enable the development and implementation of control measures that are both appropriate and sustainable if T. solium is shown to be a public health threat.  相似文献   

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The founding of Marxist psychology in the Democratic Republic of Vietnam is indissolubly linked with the development of socialist culture and science in the country. Until the Revolution of August 1945, psychology as a field of research had had no development at all. There was no special training for personnel in this field. During the colonial period, psychology was taught at the higher educational institution for teachers, and that was all. It goes without saying that it followed course outlines and textbooks sent from France and completely imbued with reactionary idealist theories.  相似文献   

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Levels of complement-fixing antibodies against rotaviruses were evaluated in the sera of 900 healthy children aged 1-9 years 300 sera were collected in the People's Democratic Republic of Yemen in September-October 1985, 300 sera were obtained in the Czech Socialist Republic in the same period and another 300 also in the Czech Socialist Republic in September-October 1986. The latter two groups were investigated in the framework of immunological surveys. A complement-fixation antigen was prepared from a simian strain of the rotavirus type SA-11 in a tissue cell line MA-104. The sera from Yemen featured lower mean titres in the age groups and thus the lowest overall titre. As the antibody titre increased, the portion of seropositive sera from Yemen declined by far more rapidly than in the Czech children, where it remained virtually the same. The sera from Yemen showed the lowest negative rate and lowest ratio of high titres. The antibody titre of 1:64 and higher was not detected in children from Yemen, while they occurred in the two groups of Czech children. There was no correlation between antibody titres and probands' sex, nor was there linear dependence of titre magnitude on age. The mean positivity rate in each group as assessed by the antibody titres was the lowest in the sera from Yemen. The percentage of positive sera in all age groups was higher in the Czech children with the exception of children from Yemen aged 6 and 9 years. The aim of the present study was to evaluate the antibody status in infant populations and thus expand knowledge of rotavirus epidemiology.  相似文献   

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