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Orton GS Yanamandra-Fisher PA Fisher BM Friedson AJ Parrish PD Nelson JF Bauermeister AS Fletcher L Gezari DY Varosi F Tokunaga AT Caldwell J Baines KH Hora JL Ressler ME Fujiyoshi T Fuse T Hagopian H Martin TZ Bergstralh JT Howett C Hoffmann WF Deutsch LK Van Cleve JE Noe E Adams JD Kassis M Tollestrup E 《Nature》2008,453(7192):196-199
Observations of oscillations of temperature and wind in planetary atmospheres provide a means of generalizing models for atmospheric dynamics in a diverse set of planets in the Solar System and elsewhere. An equatorial oscillation similar to one in the Earth's atmosphere has been discovered in Jupiter. Here we report the existence of similar oscillations in Saturn's atmosphere, from an analysis of over two decades of spatially resolved observations of its 7.8-microm methane and 12.2-microm ethane stratospheric emissions, where we compare zonal-mean stratospheric brightness temperatures at planetographic latitudes of 3.6 degrees and 15.5 degrees in both the northern and the southern hemispheres. These results support the interpretation of vertical and meridional variability of temperatures in Saturn's stratosphere as a manifestation of a wave phenomenon similar to that on the Earth and in Jupiter. The period of this oscillation is 14.8 +/- 1.2 terrestrial years, roughly half of Saturn's year, suggesting the influence of seasonal forcing, as is the case with the Earth's semi-annual oscillation. 相似文献
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Leucism in the western bluebird ( Sialia mexicana ) is reported from La Plata County, Colorado. 相似文献
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U-Pb ages of Kude and Sajia leucogranites in Sajia dome from North Himalaya and their geological implications 总被引:13,自引:0,他引:13
ZHANG Hongfei Nigel Harris Randy Parrish ZHANG Li & ZHAO Zidan .Faculty of Earth Sciences China University of Geosciences Wuhan China .Department of Earth Sciences The Open University Milton Keynes MK AA UK .NERC Isotope Geosciences Laboratory British Geological Survery Nottingham NG GG UK .School of Earth Science Land Resources China University of Geosciences Beijing China 《科学通报(英文版)》2004,49(19):2087-2092
~~U-Pb ages of Kude and Sajia leucogranites in Sajia dome from North Himalaya and their geological implications~~ FallMeetingSuppl.Abstr.,2001,0830h.
10.Lee,J.,Hacker,B.R.,Dinklage,W.S. et al.,Evolution of theKangmarDome, southernTibet:Structural, petrologic, and ther- mochronologic constraints,Tectonics,2000,19:872—895.
11.Parrish,R.R.,Roddick,J.C.,Loveridge,W.D. et al.,Ura- nium-lead analytical techniques at the geochronology laboratory,GeologicalSurvey ofCanada,Geol.Sur… 相似文献
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Thöne CC de Ugarte Postigo A Fryer CL Page KL Gorosabel J Aloy MA Perley DA Kouveliotou C Janka HT Mimica P Racusin JL Krimm H Cummings J Oates SR Holland ST Siegel MH De Pasquale M Sonbas E Im M Park WK Kann DA Guziy S García LH Llorente A Bundy K Choi C Jeong H Korhonen H Kubànek P Lim J Moskvitin A Muñoz-Darias T Pak S Parrish I 《Nature》2011,480(7375):72-74
Long γ-ray bursts (GRBs) are the most dramatic examples of massive stellar deaths, often associated with supernovae. They release ultra-relativistic jets, which produce non-thermal emission through synchrotron radiation as they interact with the surrounding medium. Here we report observations of the unusual GRB 101225A. Its γ-ray emission was exceptionally long-lived and was followed by a bright X-ray transient with a hot thermal component and an unusual optical counterpart. During the first 10 days, the optical emission evolved as an expanding, cooling black body, after which an additional component, consistent with a faint supernova, emerged. We estimate its redshift to be z = 0.33 by fitting the spectral-energy distribution and light curve of the optical emission with a GRB-supernova template. Deep optical observations may have revealed a faint, unresolved host galaxy. Our proposed progenitor is a merger of a helium star with a neutron star that underwent a common envelope phase, expelling its hydrogen envelope. The resulting explosion created a GRB-like jet which became thermalized by interacting with the dense, previously ejected material, thus creating the observed black body, until finally the emission from the supernova dominated. An alternative explanation is a minor body falling onto a neutron star in the Galaxy. 相似文献
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Precise patterning of dendritic fields is essential for neuronal circuit formation and function, but how neurons establish and maintain their dendritic fields during development is poorly understood. In Drosophila class IV dendritic arborization neurons, dendritic tiling, which allows for the complete but non-overlapping coverage of the dendritic fields, is established through a 'like-repels-like' behaviour of dendrites mediated by Tricornered (Trc), one of two NDR (nuclear Dbf2-related) family kinases in Drosophila. Here we report that the other NDR family kinase, the tumour suppressor Warts/Lats (Wts), regulates the maintenance of dendrites; in wts mutants, dendrites initially tile the body wall normally, but progressively lose branches at later larval stages, whereas the axon shows no obvious defects. We further provide biochemical and genetic evidence for the tumour suppressor kinase Hippo (Hpo) as an upstream regulator of Wts and Trc for dendrite maintenance and tiling, respectively, thereby revealing important functions of tumour suppressor genes of the Hpo signalling pathway in dendrite morphogenesis. 相似文献
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An intense stratospheric jet on Jupiter 总被引:1,自引:0,他引:1
Flasar FM Kunde VG Achterberg RK Conrath BJ Simon-Miller AA Nixon CA Gierasch PJ Romani PN Bézard B Irwin P Bjoraker GL Brasunas JC Jennings DE Pearl JC Smith MD Orton GS Spilker LJ Carlson R Calcutt SB Read PL Taylor FW Parrish P Barucci A Courtin R Coustenis A Gautier D Lellouch E Marten A Prangé R Biraud Y Fouchet T Ferrari C Owen TC Abbas MM Samuelson RE Raulin F Ade P Césarsky CJ Grossman KU Coradini A 《Nature》2004,427(6970):132-135
The Earth's equatorial stratosphere shows oscillations in which the east-west winds reverse direction and the temperatures change cyclically with a period of about two years. This phenomenon, called the quasi-biennial oscillation, also affects the dynamics of the mid- and high-latitude stratosphere and weather in the lower atmosphere. Ground-based observations have suggested that similar temperature oscillations (with a 4-5-yr cycle) occur on Jupiter, but these data suffer from poor vertical resolution and Jupiter's stratospheric wind velocities have not yet been determined. Here we report maps of temperatures and winds with high spatial resolution, obtained from spacecraft measurements of infrared spectra of Jupiter's stratosphere. We find an intense, high-altitude equatorial jet with a speed of approximately 140 m s(-1), whose spatial structure resembles that of a quasi-quadrennial oscillation. Wave activity in the stratosphere also appears analogous to that occurring on Earth. A strong interaction between Jupiter and its plasma environment produces hot spots in its upper atmosphere and stratosphere near its poles, and the temperature maps define the penetration of the hot spots into the stratosphere. 相似文献
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Mitochondrial endonuclease G is important for apoptosis in C. elegans. 总被引:10,自引:0,他引:10
Programmed cell death (apoptosis) is a tightly regulated process of cell disassembly in which dying cells and their nuclei shrink and fragment and the chromosomal DNA is degraded into internucleosomal repeats. Here we report the characterization of the cps-6 gene, which appears to function downstream of, or in parallel to, the cell-death protease CED-3 of Caenorhabditis elegans in the DNA degradation process during apoptosis. cps-6 encodes a homologue of human mitochondrial endonuclease G, and its protein product similarly localizes to mitochondria in C. elegans. Reduction of cps-6 activity caused by a genetic mutation or RNA-mediated interference (RNAi) affects normal DNA degradation, as revealed by increased staining in a TUNEL assay, and results in delayed appearance of cell corpses during development in C. elegans. This observation provides in vivo evidence that the DNA degradation process is important for proper progression of apoptosis. CPS-6 is the first mitochondrial protein identified to be involved in programmed cell death in C. elegans, underscoring the conserved and important role of mitochondria in the execution of apoptosis. 相似文献
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Radio telemetry was used to study habitat use of breeding male sage grouse ( Centrocercus urophasianus ) at a lek in northeastern Utah during 1983 and 1984. Objectives were to determine if grouse day-use areas differed significantly in sagebrush characteristics from adjacent nonuse areas and to establish a simplified method for use by land managers in identifying grouse use areas. We determined that male grouse used areas of greatest sagebrush height and cover. Our methods provide a means for land managers to identify habitat associated with a lek that is suitable for male sage grouse day use in the event sagebrush alteration is planned within 3 km of a lek. 相似文献
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Na?Li Marcus?Parrish Tze?Khee?Chan Lu?Yin Prashant?Rai Yamada?Yoshiyuki Nona?Abolhassani Kong?Bing?Tan Orsolya?Kiraly Vincent?T.?K.?Chow Bevin?P.?EngelwardEmail author 《Cellular and molecular life sciences : CMLS》2015,72(15):2973-2988
Influenza viruses account for significant morbidity worldwide. Inflammatory responses, including excessive generation of reactive oxygen and nitrogen species (RONS), mediate lung injury in severe influenza infections. However, the molecular basis of inflammation-induced lung damage is not fully understood. Here, we studied influenza H1N1 infected cells in vitro, as well as H1N1 infected mice, and we monitored molecular and cellular responses over the course of 2 weeks in vivo. We show that influenza induces DNA damage to both, when cells are directly exposed to virus in vitro (measured using the comet assay) and also when cells are exposed to virus in vivo (estimated via γH2AX foci). We show that DNA damage, as well as responses to DNA damage persist in vivo until long after virus has been cleared, at times when there are inflammation associated RONS (measured by xanthine oxidase activity and oxidative products). The frequency of lung epithelial and immune cells with increased γH2AX foci is elevated in vivo, especially for dividing cells (Ki-67-positive) exposed to oxidative stress during tissue regeneration. Additionally, we observed a significant increase in apoptotic cells as well as increased levels of DNA double strand break (DSB) repair proteins Ku70, Ku86 and Rad51 during the regenerative phase. In conclusion, results show that influenza induces DNA damage both in vitro and in vivo, and that DNA damage responses are activated, raising the possibility that DNA repair capacity may be a determining factor for tissue recovery and disease outcome. 相似文献
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