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The greater good     
Raisa B. Deber 《CMAJ》2013,185(13):E654
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Hybridization of wildlife species, even in the absence of introgression, is of concern due to wasted reproductive effort and a reduction in productivity. In this study we detail an accidental mating between a female nyala (Tragelaphus angasii) and a male greater kudu (T. strepsiceros). The hybrid was phenotypically nyala and was identified as such based on mitochondrial DNA. Further genetic analysis based on nine microsatellite markers, chromosome number and chromosome morphology however, confirmed its status as an F1 hybrid. Results obtained from a reproductive potential assessment indicated that this animal does not have the potential to breed successfully and can be considered as sterile.  相似文献   

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Vocal learning is well known among passerine and psittacine birds, but most data on mammals are equivocal. Specific benefits of vocal learning are poorly understood for most species. One case where vocal learning should be favoured by selection is where calls indicate group membership and group mates are unrelated. Female greater spear-nosed bats, Phyllostomus hastatus, live in stable groups of unrelated bats and use loud, broadband calls to coordinate foraging movements of social group mates. Bats benefit from group foraging. Calls differ between female social groups and cave colonies, and playback experiments demonstrate that bats perceive these acoustic differences. Here I show that the group distinctive structure of calls arises through vocal learning. Females change call structure when group composition changes, resulting in increased similarity among new social group mates. Comparisons of transfers with age-matched half-sibs indicate that call changes are not simply due to maturation, the physical environment or heredity. These results suggest that studies testing vocal learning in mammals could profit by focusing on vocalizations that signify group membership.  相似文献   

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E. Emanuel 《CMAJ》1975,112(7):820-821
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New taxa are described from Grus canadensis tabida: Brephosceles petersoni sp. n. (Alloptidae); Pseudogabucinia reticulata sp. n. (Kramerellidae); Geranolichus canadensis sp. n., and Gruolichus wodashae, gen. et sp. n. (Pterolichidae). Observations on resource partitioning by these mites are given.  相似文献   

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Restoration projects are increasingly widespread and many promote habitat succession and the diversity and abundance of faunal communities. These positive effects on biodiversity and abundance may extend to enhancing the ecological functioning and resilience of previously degraded ecosystems, but this is rarely quantified. This study surveyed a 200-ha restoring coastal wetland and three control wetlands in the Maroochy River, eastern Australia to compare the effects of wetland restoration on the consumption of carrion and the biodiversity, abundance, and functional diversity of functionally important fish and crustaceans. Carrion consumption by fish and crustaceans was measured every 6 months from spring 2017 until spring 2021 for nine events using a combination of baited cameras and scavenging assays. We found restoration improved rates of carrion consumption and the biodiversity, functional diversity, and abundance of scavenger species. Despite positive effects on the diversity of scavengers and carrion consumption, the abundance of two species, longfin eels (Anguilla reinhardtii) and mud crabs (Scylla serrata), was the most important predictors of carrion consumption rates. The spatial distribution of carrion consumption was concentrated in areas with high saltmarsh extent, moderate to high mangrove extent, and high salinity, which also resembled the distribution of both longfin eels and mud crabs. We show that restoration can promote the rates of key ecological functions but that increases to functions are likely to be characterized by low functional redundancy and greater complementarity. Therefore, maintaining or increasing the abundance of functionally important species should become a key objective in future restoration projects.  相似文献   

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The complex life cycle of the malaria parasite Plasmodium falciparum provides many options for vaccine design. Several new types of vaccine are now being evaluated in clinical trials. Recently, two vaccine candidates that target the pre-erythrocytic stages of the malaria life cycle - a protein particle vaccine with a powerful adjuvant and a prime-boost viral-vector vaccine - have entered Phase II clinical trials in the field and the first has shown partial efficacy in preventing malarial disease in African children. This Review focuses on the potential immunological basis for the encouraging partial protection induced by these vaccines, and it considers ways for developing more effective malaria vaccines.  相似文献   

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Despite its importance for the assessment of the effects of electric current and for technical safety considerations, not only does the electric perception threshold remain uncertain, but essential questions are still unanswered and contradictions unresolved. Via measurements at 908 persons randomly selected from the general population, including 708 adults (349 men, 359 women aged between 16 and 60 years), the problems of extrapolation to the general population and adequate statistical representation have now been overcome for the first time. The results show that existing assumptions about electric current perception need to be drastically corrected. It has been shown that the assumed electric perception threshold has been too high by a factor of 10, and that women are substantially more sensitive than men. This means that present gender-specific differences in electrosensitivity need revising. On the basis of the evidence of significant underestimation of the reaction variability in the general population, present assumptions on safety limits and safety factors urgently need to be reviewed. By no means can a relaxation of safety regulations be justified.  相似文献   

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French scientists look set for greater public scrutiny if measures proposed at a recent meeting are carried out, writes Kenneth Lee.  相似文献   

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Although relatively abundant throughout its range in eastern Australia, the greater glider (Petauroides volans) is widely considered to be sensitive to the impacts of forest fragmentation and disturbance. Genetic analysis of meta‐population structure in fragmented landscapes offers much promise in helping to understand the response of the species to such disturbance. To this end, standard size‐selected library construction and screening methods were used to develop 12 greater glider dinucleotide microsatellite primer pairs that reveal substantial genetic diversity in the species. They will be used in a variety of genetic analyses to examine population dynamics in a fragmented forest system.  相似文献   

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