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101.
Human dynamics: Darwin and Einstein correspondence patterns 总被引:2,自引:0,他引:2
In an era when letters were the main means of exchanging scientific ideas and results, Charles Darwin (1809-82) and Albert Einstein (1879-1955) were notably prolific correspondents. But did their patterns of communication differ from those associated with the instant-access e-mail of modern times? Here we show that, although the means have changed, the communication dynamics have not: Darwin's and Einstein's patterns of correspondence and today's electronic exchanges follow the same scaling laws. However, the response times of their surface-mail communication is described by a different scaling exponent from e-mail communication, providing evidence for a new class of phenomena in human dynamics. 相似文献
102.
Fraser JA Giles SS Wenink EC Geunes-Boyer SG Wright JR Diezmann S Allen A Stajich JE Dietrich FS Perfect JR Heitman J 《Nature》2005,437(7063):1360-1364
Genealogy can illuminate the evolutionary path of important human pathogens. In some microbes, strict clonal reproduction predominates, as with the worldwide dissemination of Mycobacterium leprae, the cause of leprosy. In other pathogens, sexual reproduction yields clones with novel attributes, for example, enabling the efficient, oral transmission of the parasite Toxoplasma gondii. However, the roles of clonal or sexual propagation in the origins of many other microbial pathogen outbreaks remain unknown, like the recent fungal meningoencephalitis outbreak on Vancouver Island, Canada, caused by Cryptococcus gattii. Here we show that the C. gattii outbreak isolates comprise two distinct genotypes. The majority of isolates are hypervirulent and have an identical genotype that is unique to the Pacific Northwest. A minority of the isolates are significantly less virulent and share an identical genotype with fertile isolates from an Australian recombining population. Genotypic analysis reveals evidence of sexual reproduction, in which the majority genotype is the predicted offspring. However, instead of the classic a-alpha sexual cycle, the majority outbreak clone appears to have descended from two alpha mating-type parents. Analysis of nuclear content revealed a diploid environmental isolate homozygous for the major genotype, an intermediate produced during same-sex mating. These studies demonstrate how cryptic same-sex reproduction can enable expansion of a human pathogen to a new geographical niche and contribute to the ongoing production of infectious spores. This has implications for the emergence of other microbial pathogens and inbreeding in host range expansion in the fungal and other kingdoms. 相似文献
103.
Zusammenfassung Die Synthese eines Analogen des Deamino-oxytocins, in dem ein Schwefelatom der Disulfidbrücke durch eine Methylengruppe ersetzt ist (I,X = CH2,R=H), wird beschrieben. Die Verbindung hat oxytocinähnliche biologische Wirkungen. 相似文献
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Effect of N 6 O 2 -dibutyryl cyclic 3',5'-adenosine monophosphate on the pinocytosis of brain capillaries of mice 总被引:1,自引:0,他引:1
F Joó 《Experientia》1972,28(12):1470-1471
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Marchant J 《Nature》2011,479(7374):464-467
109.
Keane TM Goodstadt L Danecek P White MA Wong K Yalcin B Heger A Agam A Slater G Goodson M Furlotte NA Eskin E Nellåker C Whitley H Cleak J Janowitz D Hernandez-Pliego P Edwards A Belgard TG Oliver PL McIntyre RE Bhomra A Nicod J Gan X Yuan W van der Weyden L Steward CA Bala S Stalker J Mott R Durbin R Jackson IJ Czechanski A Guerra-Assunção JA Donahue LR Reinholdt LG Payseur BA Ponting CP Birney E Flint J Adams DJ 《Nature》2011,477(7364):289-294
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