共查询到20条相似文献,搜索用时 15 毫秒
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Ideas are not replicators but minds are 总被引:1,自引:0,他引:1
Liane Gabora 《Biology & philosophy》2004,19(1):127-143
An idea is not a replicator because it does not consist of coded self-assembly instructions. It may retain structure as it passes from one individual to another, but does not replicate it. The cultural replicator is not an idea but an associatively-structured network of them that together form an internal model of the world, or worldview. A worldview is a primitive, uncoded replicator, like the autocatalytic sets of polymers widely believed to be the earliest form of life. Primitive replicators generate self-similar structure, but because the process happens in a piecemeal manner, through bottom-up interactions rather than a top-down code, they replicate with low fidelity, and acquired characteristics are inherited. Just as polymers catalyze reactions that generate other polymers, the retrieval of an item from memory can in turn trigger other items, thus cross-linking memories, ideas, and concepts into an integrated conceptual structure. Worldviews evolve idea by idea, largely through social exchange. An idea participates in the evolution of culture by revealing certain aspects of the worldview that generated it, thereby affecting the worldviews of those exposed to it. If an idea influences seemingly unrelated fields this does not mean that separate cultural lineages are contaminating one another, because it is worldviews, not ideas, that are the basic unit of cultural evolution. 相似文献
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A recent review of published studies revealed that predators generally have lower population densities than non-predators in a variety of communities. We report here similar results for a highly replicated study of macroinvertebrates that colonized very uniform detrital microcosms in an old field. This pattern persisted even though predators usually were smaller than non-predators, as determined by body length and volume. 相似文献
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All ras proteins are polyisoprenylated but only some are palmitoylated 总被引:174,自引:0,他引:174
The C-terminal CAAX motif of the yeast mating factors is modified by proteolysis to remove the three terminal amino acids (-AAX) leaving a C-terminal cysteine residue that is polyisoprenylated and carboxyl-methylated. Here we show that all ras proteins are polyisoprenylated on their C-terminal cysteine (Cys186). Mutational analysis shows palmitoylation does not take place on Cys186 as previously thought but on cysteine residues contained in the hypervariable domain of some ras proteins. The major expressed form of c-K-ras (exon 4B) does not have a cysteine residue immediately upstream of Cys186 and is not palmitoylated. Polyisoprenylated but nonpalmitoylated H-ras proteins are biologically active and associate weakly with cell membranes. Palmitoylation increases the avidity of this binding and enhances their transforming activity. Polyisoprenylation is essential for biological activity as inhibiting the biosynthesis of polyisoprenoids abolishes membrane association of p21ras. 相似文献
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Bassett D 《Genome biology》2001,2(7):reports4016.1-reports40162
A report on the second European conference on zebrafish genetics and development. University College, London, 19-22 April 2001. 相似文献
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The Malaria Genome Sequencing Consortium Meeting was held on 5–6 June 2001 in Cambridge, UK, and was followed by a workshop discussing the generation of new parasite-specific gene ontology (GO) terms. Present at the meeting, which focused primarily on malaria, were representatives from the research community, the sequencing centres, including the Sanger Centre (Cambridge, UK) and The Institute for Genome Research (TIGR; Rockville, MD, USA), the European Bioinformatics Institute (EBI; Cambridge, UK), Plasmo DB and the GO consortium (Cambridge, UK). 相似文献
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James H Hurley 《The EMBO journal》2015,34(19):2398-2407
The ESCRT proteins are an ancient system that buds membranes and severs membrane necks from their inner face. Three “classical” functions of the ESCRTs have dominated research into these proteins since their discovery in 2001: the biogenesis of multivesicular bodies in endolysosomal sorting; the budding of HIV-1 and other viruses from the plasma membrane of infected cells; and the membrane abscission step in cytokinesis. The past few years have seen an explosion of novel functions: the biogenesis of microvesicles and exosomes; plasma membrane wound repair; neuron pruning; extraction of defective nuclear pore complexes; nuclear envelope reformation; plus-stranded RNA virus replication compartment formation; and micro- and macroautophagy. Most, and perhaps all, of the functions involve the conserved membrane-neck-directed activities of the ESCRTs, revealing a remarkably widespread role for this machinery through a broad swath of cell biology. 相似文献
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Axel Meyer 《Trends in genetics : TIG》1998,14(12):482-483
Workshop: Novartis Foundation Symposium No. 222: Homology, London, UK, 21–23 July 1998. Followed by an Open Meeting: Homology, Welcome Trust, London, UK, 24 July 1998. 相似文献
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L. M. Edelsward 《Ethnos》2013,78(3-4):189-199
Finnish people are noted for their shyness. Shyness and a sense of independence restrict the ease with which they are able to meet strangers. This public persona need not map on the private persona, which may be warm and open to interdependence. Certain cultural institutions articulate the public and private arenas. Paramount among such institutions is the sauna, where Finns realize their responsiveness to personal and communal needs. Even in the sauna, however, norms regulate social behavior. 相似文献
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Connexins are mechanosensitive 总被引:11,自引:0,他引:11
Connexins form gap junction channels that provide a hydrophilic path between cell interiors. Some connexins, particularly the lens connexins, Cx46 and Cx50 and their orthologs, can form functional hemichannels in nonjunctional membranes. These hemichannels are a nonselective conduit to the extracellular medium and may jeopardize cell survival. The physiological function of hemichannels has remained elusive, but it has been postulated that hemichannels are involved in ATP-release caused by mechanical stimulation. Here we show with single-channel and whole cell electrophysiological studies that Cx46 hemichannels are mechanosensitive, like other families of ion channels and membrane-bound enzymes. The hemichannel response to mechanical stress is bipolar. At negative potentials stress opens the channel, and at positive potentials stress closes it. Physiologically, Cx46 hemichannels may assist accommodation of the ocular lens by providing a transient path for volume flow as the lens changes shape. mechanical stress; lens 相似文献
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EDDY CG 《Journal of the Biological Photographic Association》1957,25(4):178-180
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