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291.
292.
Both plant traits and plant–pollinator interactions are thought to influence plant mating systems. For hummingbird-pollinated plants, foraging strategy (territorial or traplining) is also expected to influence plant mating. We hypothesize that the traplining behavior of hermits promotes outcrossing, whereas the behavior of non-hermits favours self-incompatibility. Thus, selection is expected to maintain self-incompatibility in plants pollinated by non-hermits. We explore the incidence of self-incompatibility in Neotropical hummingbird-pollinated plants and its association with hummingbird behavior and plant traits. We conducted a literature review (56 species) and performed hand-pollination experiments in 27 hummingbird-pollinated plants in an Atlantic rainforest. We found that self-incompatibility (measured as <0.3 for the Index of Self-incompatibility [ISI]) occurred in only 33 % of the Neotropical hummingbird-pollinated plants. The interaction of hummingbird and habit type affected ISI, as did phylogenetic relationships. Specifically, herbs pollinated by non-hermits had higher ISI than woody plants pollinated by non-hermits, and herbs pollinated by both hermits and non-hermits. For the Atlantic rainforest plant guild, 30 % of the species were self-incompatible. ISI was higher in herbs than in woody species and increased with plant aggregation but was not dependent on foraging behavior, plant density, or floral display. Although hummingbirds differ in their foraging strategies, these behavioral differences seem to have only a minor influence on the incidence of self-incompatibility. Phylogenetic relatedness seems to be the strongest determinant of mating system in Neotropical hummingbird-pollinated plants.  相似文献   
293.
Among chemosymbiotic metazoans found at deep-sea hydrothermal vents, cold seeps and organic falls, members of the mussel clade Bathymodiolinae (Bivalvia: Mytilidae) have evolved interactions with a higher diversity of bacterial lineages than other bivalve groups. Here, we characterized the bacteria associated with “Bathymodiolus” mauritanicus and Idas-like specimens from three sites in the Northeast Atlantic (two mud volcanoes in the Gulf of Cadiz and one seamount of the Gorringe Bank). Phylogenetic analysis of bacterial 16S rRNA-encoding gene sequences demonstrated that “B”. mauritanicus has a dual symbiosis dominated by two phylotypes of methane-oxidising bacteria and a less abundant phylotype of a sulphur-oxidising bacterium. The latter was the dominant phylotype in a sympatric population of Idas-like mussels at the Darwin mud volcano. These results are the first report of a bacterial phylotype shared between two deep-sea mussels from divergent clades. This sulphur-oxidising bacterium was absent from Idas-like specimens from the other two sites (Gorringe Bank and Meknès mud volcano), in which bacterial clone libraries were dominated by other Gammaproteobacteria related to symbionts previously identified in Idas modiolaeformis from the Eastern Mediterranean. All Idas-like specimens studied herein are closely related and also related to I. modiolaeformis. However, they probably display different associations with bacteria, with the possible absence of both methane- and sulphur-oxidising symbionts at the Gorringe Bank. These results draw a very complex picture of associations between mussels and bacteria in the Northeast Atlantic, which could be highly variable depending on locale characteristics of the habitats.  相似文献   
294.
The nocturnal dwarf lemurs of Madagascar (genus Cheirogaleus) are the only primates known to be obligate hibernators. Although the physiology of hibernation has been studied widely in the western, small-bodied species, Cheirogaleus medius, no direct evidence of hibernation, i.e., body temperature recordings, has been reported for any of the three recognized eastern dwarf lemur species. We present skin temperature data collected by external collar transmitters from two eastern dwarf lemur individuals (Cheirogaleus crossleyi) captured in the high-altitude forest of Tsinjoarivo, central-eastern Madagascar. Our study species is larger in body size than western dwarf lemurs and inhabits much colder environments. We present the first evidence of hibernation in an eastern dwarf lemur species, and we compare the results with data available for the western species. Although the hibernation period is shorter in dwarf lemurs from Tsinjoarivo, minimum body temperatures are lower than those reported for C. medius. Both individuals at Tsinjoarivo showed limited passive and extended deep hibernation during which they did not track ambient temperature as observed in most western dwarf lemurs. Because ambient temperatures at Tsinjoarivo never exceed 30°C, dwarf lemurs have to experience arousals to maintain homeostasis during periods of hibernation. We show that large dwarf lemurs (>400 g) are capable of undergoing deep hibernation and suggest that cold, high-altitude forests may render hibernation highly advantageous during periods of food scarcity. This study has implications for understanding the physiology of hibernation in small-bodied lemurs.  相似文献   
295.
Social capacity building for natural hazards is a topic increasingly gaining relevance not only for so-called developing countries but also for European welfare states which are continuously challenged by the social, economic and ecological impacts of natural hazards. Following an outline of recent governance changes with regard to natural hazards, we develop a heuristic model of social capacity building by taking into account a wide range of existing expertise from different fields of research. Particular attention is paid to social vulnerability and its assessment, as well as to risk communication and risk education as specific strategies of social capacity building. We propose to distinguish between interventionist and participatory approaches, thus enabling for a better understanding of existing practices of social capacity building as well as their particular strengths and weaknesses. By way of conclusion, we encourage more research on social capacity building for natural hazards in the European context which at present is highly diverse and, at least in parts, only poorly investigated.  相似文献   
296.
Post-Triassic theropod, sauropodomorph, and ornithischian dinosaurs are readily recognized based on the set of traits that typically characterize each of these groups. On the contrary, most of the early members of those lineages lack such specializations, but share a range of generalized traits also seen in more basal dinosauromorphs. Here, we report on a new Late Triassic dinosaur from the Santa Maria Formation of Rio Grande do Sul, southern Brazil. The specimen comprises the disarticulated partial skeleton of a single individual, including most of the skull bones. Based on four phylogenetic analyses, the new dinosaur fits consistently on the sauropodomorph stem, but lacks several typical features of sauropodomorphs, showing dinosaur plesiomorphies together with some neotheropod traits. This is not an exception among basal dinosaurs, the early radiation of which is characterized by a mosaic pattern of character acquisition, resulting in the uncertain phylogenetic placement of various early members of the group.  相似文献   
297.
Environmental Science and Pollution Research - Socioeconomic and demographic factors, lifestyle and cultural characteristics may play an important role in the development of genetic damage. This...  相似文献   
298.
Environmental Science and Pollution Research - Imazethapyr, a selective systemic herbicide, is widely used in agriculture and it is frequently detected in water bodies close to application areas....  相似文献   
299.
The Brazilian Amazon is known to be a region with high levels of mercury (Hg) in the environment and studies point to an association between high levels of natural mercury in the mother rock and the vast number of clandestine gold mines. Other studies already report the contamination of fish in this region, as well as high levels of Hg in biological material from environmentally exposed populations. On the other hand, this is one of the least developed regions of the planet and it is necessary to understand the vulnerability factors in these populations that may be intoxicated by this element. The purpose of the present study was to investigate the vulnerability factors in communities from Xingu River—Amazon basin probably exposed to Hg. A cross-selection study in two cities localized in Xingu River was conducted, and the sample contained was 268 individuals. sociodemographic questions, lifestyle, diet habits and health conditions were collated. The majority of the sample was female, between 30 and 59 years old, had less than 3 years of educational level and lived in the local of study more than 240 months. There was regular fish consumption (95.9%), principally carnivorous species (80.5%). The visual problem has a highest prevalence (43.3%) between the health problems and about the symptoms of Hg intoxication, memory loss (42.9%), weakness (35.1%), fatigue (34.3%), mood changes (28.7%) and difficulties in concentration (27.2%) was most reported. The female sex, age over 60, educational level below 3 years of study, did not had flush toilet, smoke and least one chronic non-communicable disease represent higher probability to had symptoms of Hg intoxication. Lack of access to health services, low education level and income evidence the susceptibility of this community to diseases and injuries. The vulnerable groups identified in this study should be a priority in public health and environmental health policies.  相似文献   
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