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The focus of the paper is an examination of the relevance of the traditional concept mãduã for an understanding of Fijian culture, particularly in the context of modern business enterprise. The concept represents a multitude of subtle as well as clearly displayed emotions and attitudes. Though mãduã is especially relevant in situations where Fijian values are centre stage, the view put forward here is that the associated expressions and bodily postures are also relevant in modern urban contexts, where perhaps one might otherwise expect them to be discarded or at least toned down. In public discourse in Fiji, where the theme of Fijian participation in both education and business is constantly commented on and discussed, a new notion is identified, namely ‘silence’. The author suggests that it may to some degree replace and encompass mãduã The prime concern of the article, however, is to bring to the fore reflections by Fijians themselves on existential dilemmas, one of which is about how to live with mãduã in the modern context.  相似文献   

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This article examines the significance of pockets for controlling money in Highland Papua New Guinea. Contextualizing elaborate ‘systems’ for compartmentalizing monies in separate pockets, I draw upon the connection Highlanders make between transaction and skin. Pockets, I argue, offer opportunities to hide one's wealth reserves while gifting, keeping intentions opaque and leaving interlocutors guessing at the meaning of donors' speech, and forcing recipients to perceive their gift as ample. The article suggests that expectations are deliberately conventionalized in order to be exceeded, drawing parallels with Roy Wagner's notion of obviation. After characterizing Gorokan pockets and their gifting ‘logic’, I analyse how pocket‐users are themselves conventionalized as forthright or selfish in local discourse, based upon the pockets they display and where their clothes come from. Giving people clothing that includes pockets is therefore a way to regain control over their capacity to reveal wealth from their pockets.  相似文献   

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1. This is a discussion of the applicability to the phytoplankton of the concepts of ‘plant functional types’ (PFTs) and ‘functional diversity’ (FD), which originated in terrestrial plant ecology. 2. Functional traits driving the performance of phytoplankton species reflect important processes such as growth, sedimentation, grazing losses and nutrient acquisition. 3. This paper presents an objective, mathematical way of assigning PFTs and measuring FD. Ecologists can use this new approach to investigate general hypotheses [e.g. the intermediate disturbance hypothesis (IDH), the insurance hypothesis and synchronicity phenomena] as, for example, in its original formulation the IDH makes its predictions based on FD rather than species diversity.  相似文献   

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Miller RA 《Aging cell》2004,3(2):47-51
Organism envy afflicts most researchers who work on aging in mice; how frustrating it is to see the worm and fly biologists nail down milestone after milestone, citation after citation! Surely genetic trickery can produce mice that age in a comparable jiffy? Alas, our near‐total ignorance of what times the aging process makes it hard to guess what genes to tweak, if indeed aging can be mimicked a presto. Building a case that a given short‐lived mutant ages quickly is a steep and thorny path, requiring more than just plucking a symptom here and there from a list of things that sometimes go wrong in old people or old mice. The hallmark of aging is that a lot goes wrong more or less at the same time, in 2‐year‐old mice, 10‐year‐old dogs and 70‐year‐old people. Finding ways to damage one or two systems in a 6‐week or 6‐month‐old mouse is not too hard to do, but the implications of such studies for improved understanding of aging per se are at best indirect and at worst imaginary and distracting.  相似文献   

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Rebuttal to Miller: ‘Accelerated aging’: a primrose path to insight?’   总被引:1,自引:0,他引:1  
Hasty P  Vijg J 《Aging cell》2004,3(2):67-69
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Waters JM 《Molecular ecology》2011,20(21):4388-4394
Phylogeographic and evolutionary research programmes have successfully elucidated compelling genetic signatures of earth history. Particularly influential achievements include the demonstration of postglacial recolonization patterns for high-latitude taxa and phylogenetic demonstration of the 'progression rule' along oceanic island chains such as Hawaii. While both of these major biogeographic patterns clearly rely on rapid dispersal over long distances, their phylogeographic detection also apparently relies on the competitive exclusion of secondary dispersers. Such exclusion could occur either between or within species and might reflect fitness differences between lineages or, alternatively, neutral demographic processes (e.g. 'high-density blocking'). Regardless, such spatial genetic patterns would be rapidly eroded were it not for the failure of subsequent dispersers to contribute genetically to newly colonized populations. In addition to its role in revealing colonization patterns, competitive exclusion may also explain the maintenance of historic phylogeographic disjunctions long after the original physical barriers to dispersal have ceased to exist. Additionally, some of the most persuasive evidence of competitive exclusion comes from studies of anthropogenic extinction, where surviving lineages have subsequently expanded their ranges, apparently benefitting from the demise of their prehistoric sisters. Broadly, these biogeographic paradigms are united by the 'disconnect' between dispersal and colonization success, the latter being heavily influenced by inter- and intraspecific competition. Despite its apparent importance, such exclusion (especially within species) has received virtually no attention in the phylogeographic literature. Future studies should aim to test directly for the role of competitive exclusion in constraining the biogeography of highly dispersive taxa.  相似文献   

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Entomophilous flowers form the food resources for insect pollinators. Many pollinator species forage at the landscape scale and depend on floral resources that are highly variable in space and time. We present a general model approach in which the floral resources of plant communities are estimated by the floral phenology and the cover of entomophilous plant species. We applied this landscape model in a case study for three landscape sections (1.5–2.2 km2) with strongly differing land-use patterns. The comparison between a conservation area and two agricultural landscapes shows extreme differences in the quantities and in the course of floral resources.

In a stepwise simplification of the landscape model we tested the effects of input data with lower spatio-temporal resolution. Even if input data for floral phenology and vegetation have a low resolution, the landscape model allows a ranking of landscape-specific floral resource potentials. The results of the case study encourage the use of landscape models to estimate floral resource potentials. The assessment of floral resource potentials may help to define this essential landscape quality for evaluation in practical nature conservation.  相似文献   


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A common, long‐held belief is that metabolic rate drives the rates of various biological, ecological and evolutionary processes. Although this metabolic pacemaker view (as assumed by the recent, influential ‘metabolic theory of ecology’) may be true in at least some situations (e.g. those involving moderate temperature effects or physiological processes closely linked to metabolism, such as heartbeat and breathing rate), it suffers from several major limitations, including: (i) it is supported chiefly by indirect, correlational evidence (e.g. similarities between the body‐size and temperature scaling of metabolic rate and that of other biological processes, which are not always observed) – direct, mechanistic or experimental support is scarce and much needed; (ii) it is contradicted by abundant evidence showing that various intrinsic and extrinsic factors (e.g. hormonal action and temperature changes) can dissociate the rates of metabolism, growth, development and other biological processes; (iii) there are many examples where metabolic rate appears to respond to, rather than drive the rates of various other biological processes (e.g. ontogenetic growth, food intake and locomotor activity); (iv) there are additional examples where metabolic rate appears to be unrelated to the rate of a biological process (e.g. ageing, circadian rhythms, and molecular evolution); and (v) the theoretical foundation for the metabolic pacemaker view focuses only on the energetic control of biological processes, while ignoring the importance of informational control, as mediated by various genetic, cellular, and neuroendocrine regulatory systems. I argue that a comprehensive understanding of the pace of life must include how biological activities depend on both energy and information and their environmentally sensitive interaction. This conclusion is supported by extensive evidence showing that hormones and other regulatory factors and signalling systems coordinate the processes of growth, metabolism and food intake in adaptive ways that are responsive to an organism's internal and external conditions. Metabolic rate does not merely dictate growth rate, but is coadjusted with it. Energy and information use are intimately intertwined in living systems: biological signalling pathways both control and respond to the energetic state of an organism. This review also reveals that we have much to learn about the temporal structure of the pace of life. Are its component processes highly integrated and synchronized, or are they loosely connected and often discordant? And what causes the level of coordination that we see? These questions are of great theoretical and practical importance.  相似文献   

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What does it mean to talk of the religion ‘of’ a given country? I reflect on an edited volume dealing with religion in Britain and consider two related themes: the secular considered as ‘absence’ or ‘presence’, and the siting of religion not in conventional denominations or ritual practices but in spaces of encounter between religions, and between the so‐called ‘religious’ and ‘secular’.  相似文献   

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Omarakana is arguably the most renowned village in the Trobriand and anthropological worlds. It is the very centre and wellspring of the North Kiriwinan universe and thus a sacred site, serving as the home of the Tabalu chiefly paramountcy. For us anthropologists, it is ground zero for our field methodology, thanks to Malinowski's pioneering research, and probably Melanesia's most hierarchical polity. Ironically, though, very little is actually known ethnographically about Omarakana's spatial layout. In this article I seek to compensate for that deficiency, arguing that Omarakana's seemingly concentric contours encode transformations of indigenous symbolism involving recurrent metaphors drawn from at least three conjoined semantic contexts of wide distribution across the Austronesian sphere and beyond: the double bisection of ‘male’ versus ‘female’; the botanical imagery of ‘base’, ‘body’, ‘tip’, and ‘fruit’; and various elements of ‘canoe’ symbolism. This alternative view of Omarakana's spatio‐temporal plan sheds new light on various additional dimensions of Trobriand sociality and cosmology while elaborating classic and contemporary anthropological theories of dualism.  相似文献   

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There has been much speculation that the evolutionary precursors of vertebrate lymphocytes may exist in the ascidians (proto chordates), but conclusive evidence has remained elusive especially as membrane bound immunoglobulin has not been detected in any invertebrate. This paper reviews new evidence which indicates that the ‘lymphocyte-like’ cells in ascidians have functional, as well as morphological, similarities with vertebrate lymphocytes. Firstly, these cells have been linked with in vivo non-self recognition events such as allograft rejection in solitary ascidians and non-fusion reactions between colonial ascidians. Secondly, they have been shown to be cytotoxic towards xenogenic targets in vitro and to use cytolytic mechanisms similar to those of cytotoxic T-cells. Thirdly, they are able to proliferate in vitro in response to mitogens or allogeneic cells. It is therefore suggested that, apart from immunoglobulin production and clonal selection, there is persuasive evidence that the ‘lymphocyte-like’ cells of ascidians constitute a primordial form of vertebrate lymphocyte.  相似文献   

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Savannas are defined based on vegetation structure, the central concept being a discontinuous tree cover in a continuous grass understorey. However, at the high‐rainfall end of the tropical savanna biome, where heavily wooded mesic savannas begin to structurally resemble forests, or where tropical forests are degraded such that they open out to structurally resemble savannas, vegetation structure alone may be inadequate to distinguish mesic savanna from forest. Additional knowledge of the functional differences between these ecosystems which contrast sharply in their evolutionary and ecological history is required. Specifically, we suggest that tropical mesic savannas are predominantly mixed tree–C4 grass systems defined by fire tolerance and shade intolerance of their species, while forests, from which C4 grasses are largely absent, have species that are mostly fire intolerant and shade tolerant. Using this framework, we identify a suite of morphological, physiological and life‐history traits that are likely to differ between tropical mesic savanna and forest species. We suggest that these traits can be used to distinguish between these ecosystems and thereby aid their appropriate management and conservation. We also suggest that many areas in South Asia classified as tropical dry forests, but characterized by fire‐resistant tree species in a C4 grass‐dominated understorey, would be better classified as mesic savannas requiring fire and light to maintain the unique mix of species that characterize them.  相似文献   

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Keith Porter culminated his stellar career as the founding father of biological electron microscopy by acquiring, in the late 1970s, a high-voltage electron microscope (HVEM). With this magnificent instrument he examined whole-mounts of cultured cells, and perceived within them a structured cytoplasmic matrix he named the "microtrabecular lattice". Over the next decade Porter published a series of studies, together with a team of outstanding young colleagues, which elaborated his broader "microtrabecular concept." This concept posited that microtrabeculae were real physical entities that represented the fundamental organization the cytoplasm, and that they were the physical basis of cytoplasmic motility and of cell-shape determination. The present review presents Porter's original images of microtrabeculae, after conversion to a more interpretable "digital-anaglyph" form, and discusses the rise and fall of the microtrabecular concept. Further, it explains how the HVEM images of microtrabeculae finally came to be considered as an artifact of the preparative methods Porter used to prepare whole cells for HVEM. Still, Keith's "microtrabecular concept" foretold of our current appreciation of the complexity and pervasiveness of the cytoskeleton, which has now been found by more modern methods of EM to actually be the fundamental organizing principle of the cytoplasmic matrix. During the impending eclipse of Porter's microtrabecular concept in the late 1980s, many of Keith's colleagues fondly described the cell as being filled, not with protoplasm, but with "Porterplasm." Despite the fact that Keith's view was clouded by the methods of his time, it would be fitting and apt to retain this name, still today, for the ordered matrix of cytoskeletal macromolecules that exists in the living cell. In the end, the story of what happened to Porter's microtrabecular concept should be an object lesson in scientific hubris that should humble and inform all of us in cell biology, even today--particularly when we begin to think that our most recent methods and observations are achieving "the last word".  相似文献   

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Thick glistening cell walls occur in sieve tubes of all major land plant taxa. Historically, these ‘nacreous walls’ have been considered a diagnostic feature of sieve elements; they represent a conundrum, though, in the context of the widely accepted pressure–flow theory as they severely constrict sieve tubes. We employed the cucurbit Gerrardanthus macrorhizus as a model to study nacreous walls in sieve elements by standard and in situ confocal microscopy and electron microscopy, focusing on changes in functional sieve tubes that occur when prepared for microscopic observation. Over 90% of sieve elements in tissue sections processed for microscopy by standard methods exhibit nacreous walls. Sieve elements in whole, live plants that were actively transporting as shown by phloem‐mobile tracers, lacked nacreous walls and exhibited open lumina of circular cross‐sections instead, an appropriate structure for Münch‐type mass flow of the cell contents. Puncturing of transporting sieve elements with micropipettes triggered the rapid (<1 min) development of nacreous walls that occluded the cell lumen almost completely. We conclude that nacreous walls are preparation artefacts rather than structural features of transporting sieve elements. Nacreous walls in land plants resemble the reversibly swellable walls found in various algae, suggesting that they may function in turgor buffering, the amelioration of osmotic stress, wounding‐induced sieve tube occlusion, and possibly local defence responses of the phloem.  相似文献   

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