排序方式: 共有93条查询结果,搜索用时 15 毫秒
71.
72.
73.
Paranemonia vouliagmeniensis sp.n. is described from Vouliagmeni lake, a land-locked, brackish water lake near the Saronikos Gulf, Greece. It differs from Paranemonia cinerea (Contarini, 1844) in being viviparous and in the size range of the nematocysts. 相似文献
74.
75.
76.
JÉRÔME ATEUDJIEU JOHN WILLIAMS MARIE HIRTLE CÉDRIC BAUME JOYCE IKINGURA ALASSANE NIARÉ DOMINIQUE SPRUMONT 《Developing world bioethics》2010,10(2):88-98
Background: As actors with the key responsibility for the protection of human research participants, Research Ethics Committees (RECs) need to be competent and well‐resourced in order to fulfil their roles. Despite recent programs designed to strengthen RECs in Africa, much more needs to be accomplished before these committees can function optimally. Objective: To assess training needs for biomedical research ethics evaluation among targeted countries. Methods: Members of RECs operating in three targeted African countries were surveyed between August and November 2007. Before implementing the survey, ethical approvals were obtained from RECs in Switzerland, Cameroon, Mali and Tanzania. Data were collected using a semi‐structured questionnaire in English and in French. Results: A total of 74 respondents participated in the study. The participation rate was 68%. Seventy one percent of respondents reported having received some training in research ethics evaluation. This training was given by national institutions (31%) and international institutions (69%). Researchers and REC members were ranked as the top target audiences to be trained. Of 32 topics, the top five training priorities were: basic ethical principles, coverage of applicable laws and regulations, how to conduct ethics review, evaluating informed consent processes and the role of the REC. Conclusion: Although the majority of REC members in the targeted African countries had received training in ethics, they expressed a need for additional training. The results of this survey have been used to design a training program in research ethics evaluation that meets this need. 相似文献
77.
Because soil macroinvertebrates strongly modify decomposition processes, it is important to know how their abundance will respond to global change. We investigated in laboratory microcosms, the effects of elevated temperatures and reduced leaf litter quality on the life‐history traits of a saprophagous macroarthropod (development time, growth, survival and reproduction). Millipedes (Polydesmus angustus) from an Atlantic temperate forest were reared throughout their life cycle (≥16 months) under two temperature regimes differing on average by 3.3 °C; in a factorial design, they were fed either on Atlantic leaf litter or on Mediterranean leaf litter with a higher C : N ratio; humidity was consistently high. The components of the population growth rate (r) were affected positively by the temperature rise and negatively by the switch from Atlantic to Mediterranean leaf litter. When both treatments were combined, litter effects offset temperature effects. These results show that the short‐term response of saprophagous macroarthropods to warming is positive but depends on the availability of high‐quality litter, which is difficult to predict in the global change context. In a parallel experiment, conspecific millipedes from a Mediterranean population, which have evolved for a long time in a warmer climate and on poor‐quality litter, were reared at elevated temperatures on Mediterranean leaf litter. All components of r were higher than in the Atlantic population under the same conditions. This suggests that in the longer term, macroarthropods can overcome detrimental trophic interactions. Based on our study and the literature, we conclude that for decades the positive effects of warming on saprophagous macrofauna should exceed the negative effects of changes in litter quality. The abundance of those organisms in temperate forests could increase, which is confirmed by latitudinal patterns in Europe. Studies aimed at predicting the impacts of global change on decomposition will need to consider interactions with soil macroinvertebrates. 相似文献
78.
Three ontogenetic stages of the African catfish Clarias gariepinus have been used to describe and discuss the ontogeny of the hyoid musculature. During ontogeny, an asynchrony in the development of the muscles is observed: the intermandibularis and protractor hyoidei are the first to develop and which bear their insertions, followed by the hyohyoideus inferior and the sternohyoideus. The hyohyoideus abductor and adductor muscles are the last of the hyoid muscles to develop. In the juvenile stage (136.2 mm SL specimen), the intermandibularis is still present. The protractor hyoidei is well developed, as it may play an important role in the opening of the mouth, the elevation of the hyoid bars and, as a typical catfish feature, the displacement of the mandibular barbels. The protractor hyoidei arises as three pairs of muscle bundles (a pars ventralis, a pars lateralis and a pars dorsalis), of which the pars ventralis and the pars lateralis become fused to each other. This fusion gives rise to four different fields of superficial fibres for the manipulation of the mandibular barbels. The pars dorsalis, with its tendinous insertion, may be of more importance for mouth opening and/ or hyoid elevation. The hyohyoid muscle is well differentiated into an inferior, abductor and adductor muscles, acting on the hyoid bars, the branchiostegal rays and the opercular bone. 相似文献
79.
BRUNO FREDERICH DOMINIQUE ADRIAENS PIERRE VANDEWALLE 《Biological journal of the Linnean Society. Linnean Society of London》2008,95(1):92-105
The present study explores the shape changes of cranial structures directly involved in food capturing during growth after reef settlement in two species of Pomacentridae (Dascyllus aruanus and Pomacentrus pavo). Landmark‐based geometric morphometrics were used to study allometric patterns and related shape changes in four skeletal units: neurocranium, suspensorium and opercle, mandible and premaxilla. At settlement, the larvae of both species have a relatively similar morphology, especially with respect to the mandible. Their shapes suggest a feeding mode defined as ram/suction‐feeding. Ontogenetic shape changes show a shift to a suction feeding mode of prey capture. The main transformations involved are an increase in height of the suspensorium and the opercle, an elevation of the supraoccipital crest, a relative shortening of the mandible, and a lengthening of the ascending process of the premaxilla. Shape changes of the mandible in the two studied species also reflect an increase of biting capacities. The high disparity between adult shape results from differences in the rate and in the length of ontogenetic trajectories, from divergence of the ontogenetic trajectories (neurocranium, mandible, and premaxilla) and parallel shifts of the trajectories in the size‐shape space (suspensorium and opercle). In an evolutionary context, allometric heterochronies during ontogeny of different skeletal unit of the head may be considered as a basis for the explanation of the diversity of damselfishes. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 92–105. 相似文献
80.