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91.
Zusammenfassung Die gerade noch wahrnehmbare, optisch induzierte Krümmung einer horizontalen Geraden wurde unter dem Einfluss von Psilocybin untersucht. Die Droge bewirkt einen deutlichen, jedoch vorübergehenden Kompensationsverlust gegenüber der optisch induzierten Krümmung. 相似文献
92.
Cassan A Kubas D Beaulieu JP Dominik M Horne K Greenhill J Wambsganss J Menzies J Williams A Jørgensen UG Udalski A Bennett DP Albrow MD Batista V Brillant S Caldwell JA Cole A Coutures Ch Cook KH Dieters S Prester DD Donatowicz J Fouqué P Hill K Kains N Kane S Marquette JB Martin R Pollard KR Sahu KC Vinter C Warren D Watson B Zub M Sumi T Szymański MK Kubiak M Poleski R Soszynski I Ulaczyk K Pietrzyński G Wyrzykowski L 《Nature》2012,481(7380):167-169
Most known extrasolar planets (exoplanets) have been discovered using the radial velocity or transit methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17-30% (refs 4, 5) of solar-like stars host a planet. Gravitational microlensing, on the other hand, probes planets that are further away from their stars. Recently, a population of planets that are unbound or very far from their stars was discovered by microlensing. These planets are at least as numerous as the stars in the Milky Way. Here we report a statistical analysis of microlensing data (gathered in 2002-07) that reveals the fraction of bound planets 0.5-10?AU (Sun-Earth distance) from their stars. We find that 17(+6)(-9)% of stars host Jupiter-mass planets (0.3-10?M(J), where M(J) = 318?M(⊕) and M(⊕) is Earth's mass). Cool Neptunes (10-30?M(⊕)) and super-Earths (5-10?M(⊕)) are even more common: their respective abundances per star are 52(+22)(-29)% and 62(+35)(-37)%. We conclude that stars are orbited by planets as a rule, rather than the exception. 相似文献
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Rohringer N Ryan D London RA Purvis M Albert F Dunn J Bozek JD Bostedt C Graf A Hill R Hau-Riege SP Rocca JJ 《Nature》2012,481(7382):488-491
Since the invention of the laser more than 50 years ago, scientists have striven to achieve amplification on atomic transitions of increasingly shorter wavelength. The introduction of X-ray free-electron lasers makes it possible to pump new atomic X-ray lasers with ultrashort pulse duration, extreme spectral brightness and full temporal coherence. Here we describe the implementation of an X-ray laser in the kiloelectronvolt energy regime, based on atomic population inversion and driven by rapid K-shell photo-ionization using pulses from an X-ray free-electron laser. We established a population inversion of the Kα transition in singly ionized neon at 1.46 nanometres (corresponding to a photon energy of 849 electronvolts) in an elongated plasma column created by irradiation of a gas medium. We observed strong amplified spontaneous emission from the end of the excited plasma. This resulted in femtosecond-duration, high-intensity X-ray pulses of much shorter wavelength and greater brilliance than achieved with previous atomic X-ray lasers. Moreover, this scheme provides greatly increased wavelength stability, monochromaticity and improved temporal coherence by comparison with present-day X-ray free-electron lasers. The atomic X-ray lasers realized here may be useful for high-resolution spectroscopy and nonlinear X-ray studies. 相似文献
94.
MJ Claesson IB Jeffery S Conde SE Power EM O'Connor S Cusack HM Harris M Coakley B Lakshminarayanan O O'Sullivan GF Fitzgerald J Deane M O'Connor N Harnedy K O'Connor D O'Mahony D van Sinderen M Wallace L Brennan C Stanton JR Marchesi AP Fitzgerald F Shanahan C Hill RP Ross PW O'Toole 《Nature》2012,488(7410):178-184
Alterations in intestinal microbiota composition are associated with several chronic conditions, including obesity and inflammatory diseases. The microbiota of older people displays greater inter-individual variation than that of younger adults. Here we show that the faecal microbiota composition from 178 elderly subjects formed groups, correlating with residence location in the community, day-hospital, rehabilitation or in long-term residential care. However, clustering of subjects by diet separated them by the same residence location and microbiota groupings. The separation of microbiota composition significantly correlated with measures of frailty, co-morbidity, nutritional status, markers of inflammation and with metabolites in faecal water. The individual microbiota of people in long-stay care was significantly less diverse than that of community dwellers. Loss of community-associated microbiota correlated with increased frailty. Collectively, the data support a relationship between diet, microbiota and health status, and indicate a role for diet-driven microbiota alterations in varying rates of health decline upon ageing. 相似文献
95.
Thye T Owusu-Dabo E Vannberg FO van Crevel R Curtis J Sahiratmadja E Balabanova Y Ehmen C Muntau B Ruge G Sievertsen J Gyapong J Nikolayevskyy V Hill PC Sirugo G Drobniewski F van de Vosse E Newport M Alisjahbana B Nejentsev S Ottenhoff TH Hill AV Horstmann RD Meyer CG 《Nature genetics》2012,44(3):257-259
After imputation of data from the 1000 Genomes Project into a genome-wide dataset of Ghanaian individuals with tuberculosis and controls, we identified a resistance locus on chromosome 11p13 downstream of the WT1 gene (encoding Wilms tumor 1). The strongest signal was obtained at the rs2057178 SNP (P = 2.63 × 10(-9)). Replication in Gambian, Indonesian and Russian tuberculosis case-control study cohorts increased the significance level for the association with this SNP to P = 2.57 × 10(-11). 相似文献
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