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61.
We present here temporal and 0.2-2 MeV spectral data from two gamma bursts observed on 12 June and 16 August 1976, by detectors on the Solrad 11A and 11B satellites. The 12 June burst showed evidence for structure on time scales down to approximately 10 ms throughout its lifetime, whereas the 16 August burst varied only with characteristic times longer than a few tenths of a second. A search for both slow and fast spectral variability gave negative results. Accurate absolute burst times are, however, not yet available, but since both bursts were also observed by at least one Vela satellite, positions are calculable and will be reported. 相似文献
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Several disciplines within the cognitive sciences have advanced the idea that people comprehend the actions of others, including the linguistic meanings they communicate, through embodied simulations where they imaginatively recreate the actions they observe or hear about. This claim has important consequences for theories of mind and meaning, such as that people’s use and interpretation of language emerges as a kind of bodily activity that is an essential part of ordinary cognition. Daniel Weiskopf presents several arguments against the idea that experiential simulations play a major role in immediate language use and meaning. We offer several rebuttals to Weiskopf, in which we critique his interpretation of simulation theory, present additional psycholinguistic evidence supportive of the simulation perspective, and suggest that a more traditional theory of linguistic meaning and processing has little psychological and empirical validity. 相似文献
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Harris SR Clarke IN Seth-Smith HM Solomon AW Cutcliffe LT Marsh P Skilton RJ Holland MJ Mabey D Peeling RW Lewis DA Spratt BG Unemo M Persson K Bjartling C Brunham R de Vries HJ Morré SA Speksnijder A Bébéar CM Clerc M de Barbeyrac B Parkhill J Thomson NR 《Nature genetics》2012,44(4):413-9, S1
Chlamydia trachomatis is responsible for both trachoma and sexually transmitted infections, causing substantial morbidity and economic cost globally. Despite this, our knowledge of its population and evolutionary genetics is limited. Here we present a detailed phylogeny based on whole-genome sequencing of representative strains of C. trachomatis from both trachoma and lymphogranuloma venereum (LGV) biovars from temporally and geographically diverse sources. Our analysis shows that predicting phylogenetic structure using ompA, which is traditionally used to classify Chlamydia, is misleading because extensive recombination in this region masks any true relationships present. We show that in many instances, ompA is a chimera that can be exchanged in part or as a whole both within and between biovars. We also provide evidence for exchange of, and recombination within, the cryptic plasmid, which is another key diagnostic target. We used our phylogenetic framework to show how genetic exchange has manifested itself in ocular, urogenital and LGV C. trachomatis strains, including the epidemic LGV serotype L2b. 相似文献
66.
Ahmed ZM Masmoudi S Kalay E Belyantseva IA Mosrati MA Collin RW Riazuddin S Hmani-Aifa M Venselaar H Kawar MN Tlili A van der Zwaag B Khan SY Ayadi L Riazuddin SA Morell RJ Griffith AJ Charfedine I Caylan R Oostrik J Karaguzel A Ghorbel A Riazuddin S Friedman TB Ayadi H Kremer H 《Nature genetics》2008,40(11):1335-1340
67.
Krishnan KJ Reeve AK Samuels DC Chinnery PF Blackwood JK Taylor RW Wanrooij S Spelbrink JN Lightowlers RN Turnbull DM 《Nature genetics》2008,40(3):275-279
Mitochondrial DNA (mtDNA) deletions are a primary cause of mitochondrial disease and are likely to have a central role in the aging of postmitotic tissues. Understanding the mechanism of the formation and subsequent clonal expansion of these mtDNA deletions is an essential first step in trying to prevent their occurrence. We review the previous literature and recent results from our own laboratories, and conclude that mtDNA deletions are most likely to occur during repair of damaged mtDNA rather than during replication. This conclusion has important implications for prevention of mtDNA disease and, potentially, for our understanding of the aging process. 相似文献
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Crone B Dodabalapur A Lin YY Filas RW Bao Z LaDuca A Sarpeshkar R Katz HE Li W 《Nature》2000,403(6769):521-523
Thin-film transistors based on molecular and polymeric organic materials have been proposed for a number of applications, such as displays and radio-frequency identification tags. The main factors motivating investigations of organic transistors are their lower cost and simpler packaging, relative to conventional inorganic electronics, and their compatibility with flexible substrates. In most digital circuitry, minimal power dissipation and stability of performance against transistor parameter variations are crucial. In silicon-based microelectronics, these are achieved through the use of complementary logic-which incorporates both p- and n-type transistors-and it is therefore reasonable to suppose that adoption of such an approach with organic semiconductors will similarly result in reduced power dissipation, improved noise margins and greater operational stability. Complementary inverters and ring oscillators have already been reported. Here we show that such an approach can realize much larger scales of integration (in the present case, up to 864 transistors per circuit) and operation speeds of approximately 1 kHz in clocked sequential complementary circuits. 相似文献
70.
Larsson P Oyston PC Chain P Chu MC Duffield M Fuxelius HH Garcia E Hälltorp G Johansson D Isherwood KE Karp PD Larsson E Liu Y Michell S Prior J Prior R Malfatti S Sjöstedt A Svensson K Thompson N Vergez L Wagg JK Wren BW Lindler LE Andersson SG Forsman M Titball RW 《Nature genetics》2005,37(2):153-159
Francisella tularensis is one of the most infectious human pathogens known. In the past, both the former Soviet Union and the US had programs to develop weapons containing the bacterium. We report the complete genome sequence of a highly virulent isolate of F. tularensis (1,892,819 bp). The sequence uncovers previously uncharacterized genes encoding type IV pili, a surface polysaccharide and iron-acquisition systems. Several virulence-associated genes were located in a putative pathogenicity island, which was duplicated in the genome. More than 10% of the putative coding sequences contained insertion-deletion or substitution mutations and seemed to be deteriorating. The genome is rich in IS elements, including IS630 Tc-1 mariner family transposons, which are not expected in a prokaryote. We used a computational method for predicting metabolic pathways and found an unexpectedly high proportion of disrupted pathways, explaining the fastidious nutritional requirements of the bacterium. The loss of biosynthetic pathways indicates that F. tularensis is an obligate host-dependent bacterium in its natural life cycle. Our results have implications for our understanding of how highly virulent human pathogens evolve and will expedite strategies to combat them. 相似文献