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131.
Madhusudhan N Harrington J Stevenson KB Nymeyer S Campo CJ Wheatley PJ Deming D Blecic J Hardy RA Lust NB Anderson DR Collier-Cameron A Britt CB Bowman WC Hebb L Hellier C Maxted PF Pollacco D West RG 《Nature》2011,469(7328):64-67
The carbon-to-oxygen ratio (C/O) in a planet provides critical information about its primordial origins and subsequent evolution. A primordial C/O greater than 0.8 causes a carbide-dominated interior, as opposed to the silicate-dominated composition found on Earth; the atmosphere can also differ from those in the Solar System. The solar C/O is 0.54 (ref. 3). Here we report an analysis of dayside multi-wavelength photometry of the transiting hot-Jupiter WASP-12b (ref. 6) that reveals C/O?≥?1 in its atmosphere. The atmosphere is abundant in CO. It is depleted in water vapour and enhanced in methane, each by more than two orders of magnitude compared to a solar-abundance chemical-equilibrium model at the expected temperatures. We also find that the extremely irradiated atmosphere (T?>?2,500?K) of WASP-12b lacks a prominent thermal inversion (or stratosphere) and has very efficient day-night energy circulation. The absence of a strong thermal inversion is in stark contrast to theoretical predictions for the most highly irradiated hot-Jupiter atmospheres. 相似文献
132.
Chapman MA Lawrence MS Keats JJ Cibulskis K Sougnez C Schinzel AC Harview CL Brunet JP Ahmann GJ Adli M Anderson KC Ardlie KG Auclair D Baker A Bergsagel PL Bernstein BE Drier Y Fonseca R Gabriel SB Hofmeister CC Jagannath S Jakubowiak AJ Krishnan A Levy J Liefeld T Lonial S Mahan S Mfuko B Monti S Perkins LM Onofrio R Pugh TJ Rajkumar SV Ramos AH Siegel DS Sivachenko A Stewart AK Trudel S Vij R Voet D Winckler W Zimmerman T Carpten J Trent J Hahn WC Garraway LA Meyerson M Lander ES Getz G 《Nature》2011,471(7339):467-472
Multiple myeloma is an incurable malignancy of plasma cells, and its pathogenesis is poorly understood. Here we report the massively parallel sequencing of 38 tumour genomes and their comparison to matched normal DNAs. Several new and unexpected oncogenic mechanisms were suggested by the pattern of somatic mutation across the data set. These include the mutation of genes involved in protein translation (seen in nearly half of the patients), genes involved in histone methylation, and genes involved in blood coagulation. In addition, a broader than anticipated role of NF-κB signalling was indicated by mutations in 11 members of the NF-κB pathway. Of potential immediate clinical relevance, activating mutations of the kinase BRAF were observed in 4% of patients, suggesting the evaluation of BRAF inhibitors in multiple myeloma clinical trials. These results indicate that cancer genome sequencing of large collections of samples will yield new insights into cancer not anticipated by existing knowledge. 相似文献
133.
134.
Loran C. Anderson 《西北部美国博物学家》2011,43(2)
Two groups of glabrous, narrow-leaved Chrysothamnus viscidiflorus (Asteraceae) are perceived, and appropriate taxonomic combinations are made, i.e., C. v. ssp. viscidiflorus var. stenophyllus and C. v. ssp. axillaris. The two are fairly distinct geographically, and they can be separated by floral morphology. A key to all species of section Chrysothamnus (to which C. viscidiflorus belongs) is given. 相似文献
135.
Habitat use and food selection data were collected for deer mice ( Peromyscus maniculatus ), montane voles ( Microtus montanus ), Ord's kangaroo rats ( Dipodomys ordii ), and Townsend's ground squirrels ( Spermophilus townsendii ) near a sagebrush ( Artemisia tridentata )/crested wheatgrass ( Agropyron cristatum ) interface in southeastem Idaho. Significantly more captures occurred in the native sagebrush habitat than in areas planted in crested wheatgrass or in disturbed sites. Crested wheatgrass, a prolific seed producer, still accounted for over 30% of the total captures. Montane voles and Townsend's ground squirrels (during periods of aboveground activity) used the crested wheatgrass habitat throughout the summer, while deer mice and, Ord's kangaroo rats exhibited heavy use after seed set. 相似文献
136.
Two federally listed fishes, the Foskett speckled dace and Warner sucker, are endemic to Warner Basin in south central Oregon. The Foskett speckled dace is native only to a single spring in Coleman Valley. A nearby spring was stocked with dace in 1979 and 1980, and now provides a second population. The present numbers of dace probably are at their highest levels since settlement of the region. The Warner sucker historically occurred throughout much of the Warner Valley, but its distribution and abundance have been reduced by construction of reservoirs and irrigation dams and the introduction of predatory game fishes. Lentic habitats have become dominated by introduced fishes, particularly white crappie, black crappie, and brown bullhead. The largest remaining population of Warner suckers occurs in Hart Lake, where successful reproduction was documented but there is no evidence of recruitment to the adult population. 相似文献
137.
Owens Valley, California, was markedly different during the Wisconsin glacial stage from what it is today. Alpine glaciers bounded the Sierra Nevada, and pluvial Owens Lake reached highstands and overflowed its natural basin. We analyzed three layers from two packrat middens, dated to ca 23,000-14,500 yr BP, obtained from Haystack Mountain (1155 m) only 10 m above and Juniperus osteosperma ) and single-needle pinyon pine ( Pinus monophylla ) woodland existed at the site. In the layers dated to ca 17,500 and 16,000 yr BP, macrofossils document the presence of Rocky Mountain juniper ( Juniperus scopulorum ), a species that no longer occurs in California. It is suggested that meltwater from the retreating glacial ice inundated the Owens River Lake chain causing pluvial Owens Lake to reach its highstand. This caused an increase in effective moisture, due to high groundwater, allowing the mesophytic Rocky Mountain juniper to exist at the site. 相似文献
138.
Tamara K. Anderson 《西北部美国博物学家》2011,65(2)
Eighty-two soil samples and additional hand-collection in Wind Cave National Park yielded over 2000 terrestrial gastropod specimens. The specimens represent 26 different species, including a South Dakota species of concern, Vertigo arthuri . New South Dakota state records for Gastrocopta pellucida and Vertigo tridentata were recorded. Samples from grassland habitats were less likely to contain snails and had lower species richness than samples from either forest or shrubland habitats. Canyons, creek beds, bases of limestone cliffs, and shrublands are important habitats for snails in the park. 相似文献
139.
Loran C. Anderson 《西北部美国博物学家》2011,44(3)
Chrysothamnus nauseosus ssp. uintahensis (Asteraceae) is formally described and illustrated. The new subspecies represents stabilized hybrids that most probably have C. nauseosus ssp. hololeucus x C. parryi ssp. attenuatus ancestry. Morphological and anatomical comparisons are made among the putatively related taxa. 相似文献
140.