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A nickel (Ni)-plated copper-solid bullet type released up to 93 μg Ni /10 g bullet mass when immersed into meat juice for 7 days (to simulate fragments remaining in venison). A non-nickel-plated counterpart of identical construction released no Ni, but up to 250 μg copper. During thermal processing of pork cubes with embedded bullets, an average of 2.8 and up to 4.3 (maximum) μg Ni were released from the Ni-plated bullet to the surrounding meat. Average nickel and copper content in meat samples (taken in 2–3 cm distance from the shot wounds) from 30 roe deer (Capreolus capreolus) and 3 sika deer (Cervus nippon) killed with nickel-plated copper bullets did not differ significantly from those in controls (roe deer haunch). Contamination scenarios would Cu and Ni contents per portion increase moderately by 20 and 3.3 μg, respectively. In order to limit alimentary Ni uptake, the technological need for Ni-plating of bullets should be carefully evaluated.  相似文献   

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The brown bear (Ursus arctos) in Croatia is currently being managed through trophy hunting, with quotas allocated to local hunting organisations. Human–bear conflict is present at a low level, but any losses are compensated by the hunting organisations that benefit from bear hunting. Attitudes towards bears are generally positive, and the bear population appears stable, or even increasing. Croatia's current bear hunting policy relies upon both the ecological sustainability of the quotas and the economic sustainability of the hunting organisations. To address the first of these pillars of current policy, we used a two-sex matrix model of the bear population to investigate the biological sustainability of current hunting levels. The model suggests that if the annual allocated quota were fully realised, the population would suffer a considerable decrease over 10 years. A likely explanation for the mismatch between this result and the observed stability of the population is that the bear population size is underestimated. To address the second pillar, we quantified the current structure, costs and benefits of bear hunting to hunting organisations through an interview survey with hunting managers. We found that bear hunting is a substantial component of hunting organisations' income, supporting the other activities of the organisation. Croatia's recent accession to the EU will require changes in their bear management system, potentially stopping bear trophy hunting. Therefore, we assessed the changes in hunting organisations' budgets in the absence of bear hunting. Our results demonstrate that a loss of bear trophy hunting would result in a substantial loss of income to the hunting organisations. Moving bear hunting and compensation mechanisms from local management and responsibility to a more centralised system without trophy hunting, as suggested by EU legislation, will lead to considerable uncertainties. These include how to make centralised decisions on population targets and offtake levels for population control, given the uncertainty around population estimates, and on compensation payments given the loss of the current system which relies heavily on local income from trophy hunting, local relationships and informal monetary and non-monetary compensation.  相似文献   

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Here we tell a 20-year long story. It began with an easily overlooked DNA degradation (Dnd) phenomenon during electrophoresis and eventually led to the discovery of an unprecedented DNA sulfur modification governed by five dnd genes. This unusual DNA modification, called phosphorothioation, is the first physiological modification identified on the DNA backbone, in which the nonbridging oxygen is replaced by sulfur in a sequence selective and stereo-specific manner. Homologous dnd gene clusters have been identified in diverse and distantly related bacteria and thus have drawn immediate attention of the entire microbial scientific community. Here, we summarize the progress in chemical, genetic, enzymatic, bioinformatical and analytical aspects of this novel postreplicative DNA modification. We also discuss perspectives on the physiological functions of the DNA phosphorothioate modification in bacteria and their implications.  相似文献   

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野生动物狩猎、贸易和狩猎持续性研究进展   总被引:6,自引:3,他引:6  
李义明 《生物多样性》2001,9(4):414-421
过度狩猎和过度贸易是当前生物多样性保护面临的重大挑战。虎骨和犀牛角贸易、东南亚一带的活野生动物非法狩猎和贸易、俄国远东地区及中俄边境野生动物产品非法贸易、热带地区的野生动物狩猎和丛林肉食贸易以及喜马拉雅区域的野生动物非法贸易正严重威胁着全球的野生动物资源。提倡狩猎持续性是解决过度贸易和过度捕杀的途径之一。 在众多的狩猎持续性模型中,“狩猎动物避难所模型”和“空间控制模型”提倡在狩猎区建保护区,有广泛的应用前景。了解偷猎动态和特征及其对濒危动物种群的影响,协调传统医药和野生动物保护间的关系,控制边境地区的野生动物非法狩猎和贸易,以及在保护实践中运用狩猎持续性模型是未来保护关注的焦点。野生动物非法狩猎和非法贸易严重威胁着我国的生物多样性保护和持续利用,但相关的研究却比较少。建议建立野生动物捕杀和贸易的监测机构,加强相关的立法、执法和保护区管理,开展野生动物捕杀和贸易研究。  相似文献   

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Trophy hunting constitutes a major part of the global wildlife tourism industry and is connected through the export of kills to international wildlife trade. Inconsistencies between kills and exports can contribute to identifying illegal trophy hunting that constitutes a major threat to biodiversity conservation. This paper quantitatively analyses to what extent the data of trophy hunting kills and of trophy exports are consistent using the example of South Africa. Data was extracted from two different sources for the year 2018. These sources were trade data reported under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and its Trade Database on the export of trophy items from South Africa, which is compared with the South African Professional Hunting statistics (SAPHs) containing trophy kills information for each species and the country of origin of the hunter. The data of trophy hunting kills and data of trophy hunting export was found to differ to varying degrees across the countries contributing to trophy hunting and CITES-listed trophy-hunted species. We found that both databases report hunting of the same 28 threatened taxa. On the other hand, the same data reports that hunters of 64 nationalities participated in a total of 4,726 trophy kills, while only 3,131 hunting trophy items were exported from South Africa, to 37 countries as final destinations. Among the possible reasons for the discrepancies found, we suggest that the time required to taxidermize trophy specimens may delay the items being addressed to their final destination, in addition to the dual citizenship of some hunters that should also have some influence on our results, as well as the important commercial destination of Brussels Airport. The USA show the highest absolute number of trophy hunters, followed by Spain, but Denmark is the highest driver per capita. Therefore, greater participation of these countries in conservation policies for endangered species is necessary. Additionally, a more detailed differentiation of the term “trophy” to more specific terms such as claws, skins, skulls, etc. may improve reporting systems to easier identify illegal activities related to hunting.  相似文献   

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In species in which juvenile survival depends strongly on male tenure, excessive trophy hunting can artificially elevate male turnover and increase infanticide, potentially to unsustainable levels. Simulation models show that the likelihood of safe harvests can be improved by restricting offtakes to males old enough to have reared their first cohort of offspring to independence; in the case of African leopards, males were ≥7 years old. Here, we explore the applicability of an age-based approach for regulating trophy hunting of leopards. We conducted a structured survey comprising photographs of known-age leopards to assess the ability of wildlife practitioners to sex and age leopards. We also evaluated the utility of four phenotypic traits for use by trophy hunters to age male leopards in the field. Our logistic regression models showed that male leopard age affected the likelihood of survey respondents identifying the correct sex; notably, males <2 years were typically misidentified as females, while mature males (≥4 years) were sexed correctly. Mature male leopards were also more likely to be aged correctly, as were portrait photographs. Aging proficiency was also influenced by the profession of respondents, with hunters recording the lowest scores. A discriminant model including dewlap size, the condition of the ears, and the extent of facial scarring accurately discriminated among male leopard age classes. Model classification rates were considerably higher than the respective scores attained by survey respondents, implying that the aging ability of hunters could theoretically improve with appropriate training. Dewlap size was a particularly reliable indicator of males ≥7 years and a review of online trophy galleries suggested its wider utility as an aging criterion. Our study demonstrated that an age-based hunting approach is practically applicable for leopards. However, implementation would require major reform within the regulatory framework and the hunting industry.  相似文献   

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MOTIVATION: Multiple OCCurrences Analysis (Mocca) is a new method for repeat extraction. It is based on the T-Coffee package (Notredame et al., JMB, 302, 205-217, 2000). Given a sequence or a set of sequences, and a library of local alignments, Mocca extracts every segment of sequence homologous to a pre-specified master. The implementation is meant for domain hunting and makes it fast and easy to test for new boundaries or extend known repeats in an interactive manner. Mocca is designed to deal with highly divergent protein repeats (less than 30% amino acid identity) of more than 30 amino acids.  相似文献   

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Recent advances in nucleic acid diagnostic technologies have revolutionized microbiology by facilitating rapid, sensitive pathogen surveillance and differential diagnosis of infectious diseases. With the expansion and dissemination of genomic sequencing technology scientists are discovering new microbes at an accelerating pace. In this article we review recent progress in the field of pathogen surveillance and discovery with a specific focus on applications in the field of laboratory animal research. We discuss the challenges in proving a causal relationship between the presence of a candidate organism and disease. We also discuss the strengths and limitations of various assay platforms and describe a staged strategy for viral diagnostics. To illustrate the complexity of pursuing pathogen discovery research, we include examples from our own work that are intended to provide insights into the process that led to the selection of particular strategies.  相似文献   

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Much insight can be derived from records of shot animals. Most researchers using such data assume that their data represents a random sample of a particular demographic class. However, hunters typically select a non-random subset of the population and hunting is, therefore, not a random process. Here, with red deer (Cervus elaphus) hunting data from a ranch in Toledo, Spain, we demonstrate that data collection methods have a significant influence upon the apparent relationship between age and weight. We argue that a failure to correct for such methodological bias may have significant consequences for the interpretation of analyses involving weight or correlated traits such as breeding success, and urge researchers to explore methods to identify and correct for such bias in their data.  相似文献   

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Group foraging has been suggested as an important factor for the evolution of sociality. However, visual cues are predominantly used to gain information about group members'' foraging success in diurnally foraging animals such as birds, where group foraging has been studied most intensively. By contrast, nocturnal animals, such as bats, would have to rely on other cues or signals to coordinate foraging. We investigated the role of echolocation calls as inadvertently produced cues for social foraging in the insectivorous bat Noctilio albiventris. Females of this species live in small groups, forage over water bodies for swarming insects and have an extremely short daily activity period. We predicted and confirmed that (i) free-ranging bats are attracted by playbacks of echolocation calls produced during prey capture, and that (ii) bats of the same social unit forage together to benefit from passive information transfer via the change in group members'' echolocation calls upon finding prey. Network analysis of high-resolution automated radio telemetry confirmed that group members flew within the predicted maximum hearing distance 94±6 per cent of the time. Thus, echolocation calls also serve as intraspecific communication cues. Sociality appears to allow for more effective group foraging strategies via eavesdropping on acoustical cues of group members in nocturnal mammals.  相似文献   

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For decades, a central question in neuroscience has been: How does the brain support navigation? Recent research on navigation has explored how brain regions support the capacity to adapt to changes in the environment and track the distance and direction to goal locations. Here, we provide a brief review of this literature and speculate how these neural systems may be involved in another, parallel behavior—hunting. Hunting shares many of the same challenges as navigation. Like navigation, hunting requires the hunter to orient towards a goal while minimizing their distance from it while traveling. Likewise, hunting may require the accommodation of detours to locate prey or the exploitation of shortcuts for a quicker capture. Recent research suggests that neurons in the periaqueductal gray, hypothalamus, and dorsal anterior cingulate play key roles in such hunting behavior. In this review, we speculate on how these regions may operate functionally with other key brain regions involved in navigation, such as the hippocampus, to support hunting. Additionally, we posit that hunting in a group presents an additional set of challenges, where success relies on multicentric tracking and prediction of prey position as well as the position of co-hunters.  相似文献   

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