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1.
毒素战剂是重要的生物战剂之一,其最大的威胁来自它的高毒性和缺乏有效的防治手段。在毒素战剂中,肉毒毒素、志贺毒素、蓖麻毒素、相思子毒素等属于致死性生物战剂,葡萄球菌肠毒素B属于失能性生物战剂。生防疫苗作为毒素战剂的一种重要的有效预防手段,一直备受关注,但目前绝大部分毒素战剂的疫苗都还在研制中,随着分子生物学技术的快速发展,几种重要毒素战剂的重组疫苗研究已获得重要突破。我们重点介绍肉毒毒素、志贺毒素、蓖麻毒素、相思子毒素、葡萄球菌肠毒素B等毒素战剂生防疫苗的研究与发展。  相似文献   

2.
We consider patterns in the evolution of canoe technology in the eastern Pacific relative to three general processes: movement of canoe traits along the Polynesian settlement sequence, adaptations to local island environment, and post-settlement interaction between island groups. Using model selection methods on the distributions of canoe technology, we show that social and ecological covariates together consistently outperform each considered individually, though knowledge of island area and post-settlement trading spheres does not add explanatory power. In particular, decorative canoe traits are not effectively explained by either our ecological or transmission models. We also estimate negative effects from both settlement sequence and island geomorphology, consistent with the die-off of particular canoe designs on resource-rich high island groups such as Hawaii and New Zealand. This decline in measured traits may be owing to the lifting of ecological constraints on population size or building materials.  相似文献   

3.
Supernatural belief presents an explanatory challenge to evolutionary theorists—it is both costly and prevalent. One influential functional explanation claims that the imagined threat of supernatural punishment can suppress selfishness and enhance cooperation. Specifically, morally concerned supreme deities or ‘moralizing high gods'' have been argued to reduce free-riding in large social groups, enabling believers to build the kind of complex societies that define modern humanity. Previous cross-cultural studies claiming to support the MHG hypothesis rely on correlational analyses only and do not correct for the statistical non-independence of sampled cultures. Here we use a Bayesian phylogenetic approach with a sample of 96 Austronesian cultures to test the MHG hypothesis as well as an alternative supernatural punishment hypothesis that allows punishment by a broad range of moralizing agents. We find evidence that broad supernatural punishment drives political complexity, whereas MHGs follow political complexity. We suggest that the concept of MHGs diffused as part of a suite of traits arising from cultural exchange between complex societies. Our results show the power of phylogenetic methods to address long-standing debates about the origins and functions of religion in human society.  相似文献   

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5.
All of the samples yielded podocopid ostracods. Most of the faunas from Pitcairn and Oeno were poorly preserved and sparse; those from Henderson were much more abundant, more diverse and better preserved. Only 33 species are recorded from the joint fauna and this may reflect the limited number of environments sampled or the remote geographical situation of the islands. At least 20 species (and a new genus) are restricted to the islands. Other species are known from the Solomon Islands, Australia and Indonesia. Of a considerable number of Indo-Pacific pandemic species, only three Kotoracythere inconspicua (Brady), Tenedocythere transoceanica (Teeter) and Triebelina sertata (Triebel) have been identified to date. The fauna is not, however, nearly so endemic as that of Easter Island on which the two authors are currently working.  相似文献   

6.
7.
Seven species of Mecyclothorax Sharp precinctive to Mont Mauru, Tahiti, Society Islands are newly described: Mecyclothorax tutei sp. n., Mecyclothorax tihotii sp. n., Mecyclothorax putaputa sp. n., Mecyclothorax toretore sp. n., Mecyclothorax anaana sp. n., Mecyclothorax pirihao sp. n., and Mecyclothorax poro sp. n. These seven constitute the first representative Mecyclothorax species recorded from Mauru, and their geographic restriction to this isolated massif defines it as a distinct area of endemism along the highly dissected eastern versant of the Tahiti Nui volcano. Each of the new species has a closest relative on another massif of Tahiti Nui, supporting speciation associated with vicariance caused by extensive erosional valley formation, especially the development of Papenoo Valley. Comparison of the known elevational distributions of the new discoveries on Mont Mauru to the elevational diversity profile of the comparatively well-sampled Mont Marau, northwest Tahiti Nui, suggests that numerous Mecyclothorax species remain to be discovered in higher-elevation habitats of Mont Mauru.  相似文献   

8.
Abstract

I seek to understand two dimensions in the evolution and practices of medical institutions in the USA. First, I ask, how and why do medical organizations limit, suspend, or redirect profit-oriented functions to abide by principles of altruism and still survive in a competitive market economy? Reaching out to poor and immigrant populations entails non-economic factors, including the deployment of religious and humanitarian narratives. Conversely, the extent and character of legislative actions supporting philanthropic endeavours is closely related to mobilization at the grassroots level. I investigate the ways in which community organizations bring about changes to support practices that confound, at least to some extent, market expectations and underscore the significance of political action to secure health care services on behalf of low-income populations, including immigrants.  相似文献   

9.
Both leucomorph and anamorph developmental stages of Anamixis bananaramasp. n., are illustrated and described from shallow back reef environments of Moorea, French Polynesia. Distinguished by vestigial first gnathopods that persist in post-transformational adult males, this is the second species in the genus to exhibit this unusual character. In other features such as coxae and second gnathopods Anamixis bananaramasp. n. resembles other Pacific Plate endemics of Anamixis known from the region. Specific host association is not documented but suspected to be small calcareous asconoid sponges associated with coral rubble.  相似文献   

10.
Aim Remote oceanic islands often provide good illustrations of adaptive radiations, but phylogenetic studies have also demonstrated unexpected multiple colonization events for a given archipelago. In this study we investigate the relationships among endemic populations of the Marquesas reed‐warbler, Acrocephalus mendanae Tristram, 1883, which have colonized nearly all islands of this remote Polynesian archipelago, and which exhibit a very uniform plumage pattern. We study the phylogeny and morphology of all subspecies in the Marquesas, providing an examination of the position of the Marquesas lineages in relation to reed‐warblers distributed across multiple Polynesian archipelagos. Location This study focused on all the main islands of the Marquesas archipelago, along with samples from other Polynesian archipelagos (Society, Tuamotu, Austral, Cook, Kiribati) and Australia. Methods We used mitochondrial DNA markers (cytochrome b and ND2 genes) to develop a phylogeny of the main eastern Polynesian taxa. All subspecies for the Marquesas were investigated, including multiple individuals per island. Phylogenetic analyses using maximum‐likelihood and Bayesian approaches were employed to infer relationships among A. mendanae populations and between the main Polynesian archipelagos. Morphometric analyses based on 110 specimens from museum collections were performed on external characters to investigate the differences between islands, and these results were compared to the phylogeny. Results Our data indicate that the Marquesas reed‐warbler is in fact a polyphyletic taxon including two independent lineages: the northern Marquesas reed‐warbler, closely related to the Tuamotu reed‐warbler, and the southern Marquesas reed‐warbler, sister taxon to that endemic to the Kiribati. Analyses of morphological characters show that the size and shape features of the Marquesas reed‐warblers exhibit high plasticity linked to adaptation to ecological factors, particularly habitat richness (the diversity of vegetation structure that provides suitable resources and habitat for reed‐warblers, simplified here as the number of indigenous plant species). Main conclusions Our results suggest that reed‐warblers have successfully colonized the Marquesas archipelago, one of the most remote groups of islands in the Pacific Ocean, at least twice. Both events occurred more or less simultaneously at ca. 0.6 Ma, and are more recent than the islands' formation. We outline the taxonomic consequences of our phylogeny and discuss the supertramp strategy of reed‐warblers in the Pacific.  相似文献   

11.
During 1991 and 1992 the first regular field observations of green turtles, Chelonia mydas , on the Pitcairn Islands (South Pacific) revealed that nesting occurs only on Henderson where about 10 females laid eggs (c. 1% of the French Polynesian population). Substrates on Pitcairn and Ducie Atoll are unsuitable for nesting and no signs of nesting were found on Oeno Atoll where the terrain appears suitable.  相似文献   

12.
The skeleton of a middle-aged female showing an unusual pattern of congenital, traumatic, and degenerative pathology was recovered from a small Kayenta Anasazi site located near the confluence of Bright Angel Creek with the Colorado River in the Inner Gorge of Grand Canyon. The atlas is fused with the base of the skull and C2 is fused with C3. The cervical region was subjected to hyperextension, perhaps through use of a tumpline, with resultant reduction of the neural canal to 8 mm, a condition that quite likely led to neurological problems. The skeleton also includes a depression fracture of the lateral condyle of the left tibia. Complete, bilateral spondylolysis of L5 led to an olisthesis of approximately 15 mm. The disc between L5 and S1 then ossified, most likely from staphylococcus bacteremia, making the olisthesis permanent and thereby creating a unique arachaeological specimen. Although spondylolysis is usually viewed as a stress fracture, the general pattern of pathology in this individual makes it necessary to consider an etiology of acute trauma.  相似文献   

13.
The possible origins of the 12 superfamilies of the Spirurida are considered, based on comparative morphology, host and geographic distributions. The available evidence suggests a complex origin of these nematodes, some families being derived from the Seuratoidea, and others from the Cosmocercoidea (Ascaridida). The spirurid radiation is an old one and seems to have occurred primarily in the Secondary or early Tertiary eras. Since then, expansion has occurred with host capture as a prominent mechanism. The Dracunculoidea Procamallanidae and Camallanidae are probably derived from the Chitwoodchabaudiidae and the Rictularioidea from the Schneidernematidae. The Seuratidae may have given rise to the Gnathostomatoidea, the Physalopteroidea, the Thelazioidea, the Habronematoidea, the Spiruroidea and the Acuarioidea. The filarioid nematodes appear to have several origins with the Diplotriaenoidea derived from the Spiruroidea, while constituents of the Aproctoidea derived from the Cystidicolinae, the Seuratoidea and the Spiruroidea. The Filarioidea are thought to have arisen from the Spiruroidea and the Thelazioidea. The evolution of tissue parasitism as a secondary phenomenon is considered in various groups.  相似文献   

14.
The question of how an endocast (or brain) is oriented within a skull that is positioned in the Frankfurt plane is investigated for African great apes, early hominids STS 71, KNM-ER 1813 and KNM-ER 1470, and modern humans using a 3SPACE digitizer. Our results suggest that, rather than being positioned in the orientation in which isolated brains (endocasts) are conventionally illustrated, brains within skulls that are oriented in the Frankfurt plane tend to be inclined so that the frontal pole is higher than the occipital pole, especially inHomo. These preliminary findings have implications for interpreting early hominid endocasts such as that of AL 162-28.  相似文献   

15.
Population, Warfare, and the Male Supremacist Complex   总被引:1,自引:0,他引:1  
We present cross-cultural data on the existence of a pervasive institutional and ideological complex of male supremacy in band and village sociocultural systems, and we identify warfare as the most important cause of this complex. We explain the perpetuation of warfare in band and village society and its interaction with selective female infanticide as a response to the need to regulate population growth in the absence of effective or less costly alternatives. Our hypothesis is supported by a demographic analysis of 561 local band and village populations from 112 societies.  相似文献   

16.
  • 1 The streams of French Polynesia contain several species of Neritidae and Thiaridae (Mollusca: Gastropoda). The neritids are dioecious and amphidromous with a freshwater adult stage and a poorly known, marine larval stage. The thiarids are parthenogenetic and viviparous, and rely on passive dispersal for colonisation of new habitats.
  • 2 Populations of the neritid Clithon spinosus and the thiarids Melanoides tuberculata and Thiara granifera were analysed using mitochondrial DNA sequences from COI to compare the population structure of the snails at three different scales: between streams (N = 9), between islands (N = 4), and between age and distance of paired islands.
  • 3 The amphidromous C. spinosus showed no evidence of genetic isolation at any of the scales tested (Fst values 0.02). Parsimony analyses resulted in two haplotype clusters separated by a three‐step segment, which were not linked to geographic isolation. The larval phase of C. spinosus is most likely a long‐lived planktotroph and a very effective disperser.
  • 4 Two haplotypes of M. tuberculata, separated by 16 base pairs, were found. Both haplotypes were found in snails on all islands, and individuals representing both were often collected in the same habitat. One haplotype of T. granifera was found. M. tuberculata has the characteristics of the ‘general‐purpose genotype’ of clonal population structure and although it relies on passive dispersal, it has colonised nearly all freshwater habitats on the islands.
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17.
The sporozoans comprise a coherent group of protozoans, with characteristic and complex life cycles, containing 4–5000 species parasitic in invertebrates, particularly annelids and arthropods, and vertebrates. The group is a very successful one but neither its origins nor evolution are well understood. Considerations of traditional life cycles combined with newer molecular methodologies have thrown some light on the evolutionary expansions of the main groups of sporozoans, the gregarines, coccidia, haemosporidians and piroplasms. The sporozoans of economic importance such as the coccidia, malaria parasites and piroplasms have received most attention but the data obtained have also thrown new light on the possible evolution of less well studied groups and it is concluded that conclusions based on simple comparisons of life cycles will have to be modified. It is also clear that humans have played a major part in affecting the distribution and present abundance of many sporozoans of economic significance and probably also those of less importance, and that the rates of evolutionary expansion are much more rapid than previously thought.  相似文献   

18.
This paper reports the breeding biology and nesting seasons of the gadfly petrels which nest on the four islands of the Pitcairn group, Pitcairn, Henderson, Oeno and Ducie. The species currently breeding are Murphy's petrel Pterodroma ultima , Kermadec petrel P. neglecta , Herald petrel P. heraldica and Henderson petrel P. atrata. Of these, Murphy's petrel is the most numerous; an estimated 250000 pairs bred on Ducie, which is probably the major breeding station of the species. Novel basic breeding data for Murphy's petrel are presented. Incubation spells, averaging 19.3 days, are exceptionally long for a petrel. Phoenix petrel P. alba appears to have ceased to breed on the Pitcairn Islands since the 1922 surveys of the Whitney Expedition. Nesting success was low on Henderson Island during the study. For all four breeding species, less than 20% of eggs laid yielded fledglings. Failure occurred at the early chick stage and observations indicated that it was due to predation by Pacific rats Rattus exulans. Although rats are present on Ducie, predation was apparently less severe there. The situation on Oeno may be intermediate. I consider how the populations of Henderson are maintained in the face of this intense predation. The Murphy's petrel population may be sustained by immigration from Ducie while the Herald and Henderson petrel populations could be undergoing a long-term decline on Henderson. It is not clear how the Kermadec petrel population is maintained. The conservation implications of these findings are discussed.  相似文献   

19.
Margaret Mead, Reo Fortune, and Mountain Arapesh Warfare   总被引:2,自引:0,他引:2  
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20.
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