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《Plains anthropologist》2013,58(76):1-13
AbstractA new research paradigm—the Co-Influence Sphere Model—is developed and applied to the archaeological record to account for the variability in prehistoric ceramics of Southwestern Manitoba. The Co-Influence Sphere Model emphasis the co-existence, interaction, and territorial overlapping of groups in the prehistoric and early historic periodsThe model requires an evaluation of the seasonally fluctuating resource potential across the Plains, ‘Aspen Parkland, and Boreal Forest; the mobility and multiple biome utilization of historic groups; and the interaction of historic groups through formalized trade networks, conflict, and sharing of similar resources. The earlier emphasis on chronology and mutually exclusive home territories of historic groups is replaced by a more realistic and dynamic model of groups with core, secondary, and tertiary subsistencesettlement areas in which groups interact to varying degreesFor Southwestern Manitoba, the earlier Chronological Model (with one identifiable phase and one historic tribe per period and area) is replaced by a complicated record of four complexes during the Middle Woodland Stage, nine complexes during the Late Woodland Stage, and possibly 15 different ethnic groups in the protohistoric and early historic periods Furthermore, there is a shift in interrelationships between territorially overlapping occupants from the Boreal Forest and Plains with the advent of the Late Woodland Stage that is accompanied by the development of horticultural villages, the growth and fission of human populations, and symbiotic relationships between horticulturalists and hunters.Use of the dynamic Co-Influence Sphere Model requires a shift away from defining complexes and seeking causal relationships or processes within a small research region. The environmental limitations, cultural history, and cultural processes of any region, and particularly a region like Southwestern Manitoba (which partly straddles an ecotone) can be determined only by an exhaustive study of fluctuating resources, ethnohistory, archaeological history, and variation in subsistence-settlement patterns beyond the region. In order to apply the Co-Influence Sphere Model to Southwestern Manitoba, local data have been related to developments in the Boreal Forest, Upper Great Lakes, Upper Mississippi, and Northern Plains. Relationships are determined by assessing regions and areas beyond the local research universe, rather than attempting to discover processes on the basis of limited local data. 相似文献
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Powell JA 《Trends in ecology & evolution》1992,7(1):10-15
Purposeful pollination of yucca by females of a moth that produces larvae that feed on some of the seeds is a classic example of plant-animal mutualism. Recent research has focused on the complex interspecific nature of this association. Pollinators are members of two genera with different oviposition and larval biologies. There appear to be several sibling species among populations of the pollinator that were formerly considered to be a single widespread generalist, and these may include sympatric nonpollinator 'cheaters'. Bogus yucca moths, members of a third genus, which neither transport pollen nor feed in the seed but depend upon the inflorescences, are niche specific and often host-species specific and include one leaf-mining species. Their larvae can spend many years in diapause before synchronized development. 相似文献
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Summary The distribution of radioactivity from 3H-putrescine was studied in intact and degenerated sciatic nerves, and spinal ganglia of rats by means of high resolution autoradiography. During the first three days after the administration of the labeled putrescine, the main proportion of radioactive material in the nerves was represented by spermidine and putrescine. Both, in intact and degenerating nerves, developed silver grains were deposited in all cellular components of the nervous tissue, the myelin sheath being markedly tagged. Perineural tissue was also labeled considerably, however, there was no significant amount of label in the extracellular space and in the collagen fibrils. The possible physiological significance of putrescine and spermidine in myelin and in other cellular components of nerves is discussed.Herrn Prof. Dr. W. Krücke zum 60. Geburtstag gewidmet. 相似文献
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Interrelationships between zinc and immune function 总被引:4,自引:0,他引:4
Zinc deficiency is a common nutritional problem observed both in human and in animal populations that has profound effects on host defense mechanisms. Using the young adult mouse as a model, it has been demonstrated that a moderate period of suboptimal zinc causes thymic atrophy, lymphopenia, and alterations in the proportions of the various subsets of lymphocytes and mononuclear phagocytes. As a result, antibody-mediated responses to both T cell-dependent and T cell independent antigens are significantly reduced. Cytolytic T cell responses, natural killer (NK) cell activity, and delayed-type hypersensitivity (DTH) reactions are also depressed. Suboptimal zinc during in utero development of mice causes persistent states of immunodeficiency in the offspring that can even be transferred to subsequent generations. In regard to human immunological consequences of zinc deficiency, patients with the genetic disorder of zinc absorption, acrodermatitis enteropathica, also exhibit atrophic thymuses, lymphopenia, anergic DTH responses, and reduced NK cell activity. Patients suffering from sickle cell anemia or uremia with associated deficiencies in zinc exhibit similar immune deficiencies. An additional outcome of these studies has been shown to be an essential cofactor for thymulin, one of the thymic hormones. Furthermore, addition of zinc salts to culture can polyclonally activate lymphocytes as well as augment responses to mitogens in adjuvant-like manner. 相似文献
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SYNOPSIS. The concept of the Actinopterygii as a natural groupof fishes was not generally accepted until early in this century.Ever since, the characterization of the group has been blurredby the problem of cladistian (polypterid) relationships. Froma review of the structure of polypterids and actinopts, it isconcluded that Cladistia are the sistergroup of Recent actinopterygians(Actinopteri), the two groups together comprising the Actinopterygii.Recent chondrosteans are more closely related to higher actinopts(Neopterygii) than to cladistians. The extinct Palaeonisciformesappear to be a paraphyletic group, comprising stem-group actinopterygians(e.g., Cheirolepts), stem-group actinopterans (e.g., Moythomasia)and relatives of higher actinopterans (e.g., Pteroniscus) 相似文献
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The circadian rhythms of oxygen consumption and insecticide sensitivity (to dichlorvos, a rapid-acting organophosphate) in adult confused flour beetles (Tribolium confusum du Val) were determined using a LD 12:12 lighting regimen and other standardized conditions. Analysis included fitting a 24 h cosine curve to the data to estimate rhythm characteristics. Relationships between rhythms in oxygen consumption and insecticide sensitivity were evaluated on the basis of each rhythm's acrophase (timing of high point). The acrophase of oxygen consumption occurred on the average about 3 h after the middle of the daily dark span. Maximum insecticide sensitivity, based upon the reciprocal of the LC70, occurred about 2 h earlier. Although the times are fairly close, the difference between the two acrophases was statistically significant. 相似文献
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Interrelationships of lower actinopterygian fishes 总被引:2,自引:0,他引:2
The lower actinopterygian fishes are classified using dermal skull roof pattern, in particular the various configurations displayed by the bones on the otic branch of the infraorbital canal (dermosphenotic, intertemporal-supratemporal/dermopterotic). Where possible these patterns are related to the sequential acquisition of derived features, and the resulting cladogram represents a synthesis of dermal bone pattern and endochondral and dermal skeletal characters. We have proposed 27 terminal groups which we tentatively regard as monophyletic and have concluded that Polypterus is the most primitive living taxon, that the Chondrostei is the sister-group of Saurichthys and Luganoia the most derived stem-group neopterygian. 相似文献
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叶片性状能够反映植物对环境的适应.认识喀斯特地区兰科植物的叶片性状及其适应意义对其科学合理的保育具有重要参考价值.本文于干季与雨季研究了广西雅长兰科植物自然保护区内落叶、常绿地生、常绿石附生三种类型共19种野生兰科植物的叶片性状及其相互关系,并比较了不同类型兰科植物之间的差异.其中18种兰科植物为C3植物,仅棒叶鸢尾兰(Oberonia myosurus)为CAM植物.相比于落叶兰,常绿兰具有较高的比叶重( LMA)和叶片碳氮比(C/N),但其叶片氮、磷含量较低.在常绿兰科植物中,石附生兰的叶片Ca含量与δ13C高于地生兰.石附生兰的叶片磷含量在雨季要高于干季,而地生兰的叶片δ13C在于季要高于雨季.该地区常绿兰科植物的N/P值>16,表明其可能受到磷的限制. 相似文献
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Interrelationships of the ostariophysan fishes (Teleostei) 总被引:2,自引:0,他引:2
The history of ostariophysan classification is summarized and it is noted that traditional concepts of relationships have never been supported by characters found to be unique to the taxa. We present a new hypothesis of relationships among four of the five major ostariophysan lineages: Cypriniformes, Characiformes, Siluroidei, and Gymnotoidei (Otophysi). Cypriniforms are the sister-group of the remaining three (Characiphysi), and characiforms are the sister-group of siluroids plus gymnotoids (Siluriformes). Placement of the Gonorynchiformes as the sister-group of the Otophysi is supported by additional evidence. Each of the five lineages is monophyletic. Analysis was concentrated upon species thought to be the least specialized within each lineage; choices of these species are discussed. Chanos is determined to be a relatively primitive gonorynchiform morphologically and the sister-group of all other Recent members of the order. Opsariichthys and Zacco are found to be morphologically primitive cypriniforms. We propose that a monophyletic group comprising the Citharinidae and Distichodontidae forms the sister-group of all other characiforms. Within the two families, Xenocharax is the least specialized. We suggest that Hepsetus, the erythrinids, and the ctenoluciids are more derived than the distichodontids and citharinids, and may form a monophyletic group within die characiforms. The traditional hypothesis that Diplomystes is the primitive sister-group of all Recent siluroids is substantiated. Our evidence suggests that Sternopygus is the most primitive gymnotoid morphologically; but rather than being the sister-group of all other gymnotoids, it is the primitive sister-group within a lineage called the Sternopygidae by Mago-Leccia. Previous explanations of otophysan distribution have been based on notions of relationships which are unsupported by the evidence presented herein. Our own analysis of relationships serves primarily to make clear the extent of sympatry, and therefore the probability of dispersal, among the major ostariophysan lineages. The extent of sympatry, together with the widespread distribution of ostariophysans, suggests that the group is older than previously supposed, and our hypotheses of relationships among the characiforms implies that many of the extent characiform lineages evolved before the separation of Africa and South America. Further understanding of ostariophysan distribution must await phylogenetic analysis within each of the five major lineages so that distributions linked with vicariance patterns and dispersal events can be sorted out. 相似文献
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BURTON K 《Biochemical Society symposium》1957,(14):60-73; discussion, 73-4