A 5-micron-bright spot on Titan: evidence for surface diversity     

Barnes JW  Brown RH  Turtle EP  McEwen AS  Lorenz RD  Janssen M  Schaller EL  Brown ME  Buratti BJ  Sotin C  Griffith C  Clark R  Perry J  Fussner S  Barbara J  West R  Elachi C  Bouchez AH  Roe HG  Baines KH  Bellucci G  Bibring JP  Capaccioni F  Cerroni P  Combes M  Coradini A  Cruikshank DP  Drossart P  Formisano V  Jaumann R  Langevin Y  Matson DL  McCord TB  Nicholson PD  Sicardy B 《Science (New York, N.Y.)》2005,310(5745):92-95

Observations from the Cassini Visual and Infrared Mapping Spectrometer show an anomalously bright spot on Titan located at 80 degrees W and 20 degrees S. This area is bright in reflected light at all observed wavelengths, but is most noticeable at 5 microns. The spot is associated with a surface albedo feature identified in images taken by the Cassini Imaging Science Subsystem. We discuss various hypotheses about the source of the spot, reaching the conclusion that the spot is probably due to variation in surface composition, perhaps associated with recent geophysical phenomena.  相似文献   

Photometry from voyager 2: initial results from the neptunian atmosphere, satellites, and rings     

Lane AL  West RA  Hord CW  Nelson RM  Simmons KE  Pryor WR  Eposito LW  Horn LJ  Wallis BD  Buratti BJ  Brophy TG  Yanamandra-Fisher P  Colwell JE  Bliss DA  Mayo MJ  Smythe WD 《Science (New York, N.Y.)》1989,246(4936):1450-1454

The Voyager photopolarimeter successfully accomplished its objectives for the Neptune encounter, performing measurements on the planet, several of its satellites, and its ring system. A photometric map of Neptune at 0.26 micrometer (microm) shows the planet to be bland, with no obvious contrast features. No polar haze was observed. At 0.75 microm, contrast features are observed, with the Great Dark Spot appearing as a low-albedo region and the bright companion as being substantially brighter than its surroundings, implying it to be at a higher altitude than the Great Dark Spot. Triton's linear phase coefficients of 0.011 magnitudes per degree at 0.26 microm and 0.013 magnitudes per degree at 0.75 microm are consistent with a solid-surface object possessing high reflectivity. Preliminary geometric albedos for Triton, Nereid, and 1989N2 were obtained at 0.26 and 0.75 microm. Triton's rotational phase curve shows evidence of two major compositional units on its surface. A single stellar occultation of the Neptune ring system elucidated an internal structure in 1989N1R, in the approximately 50-kilometer region of modest optical depth. 1989N2R may have been detected. The deficiency of material in the Neptune ring system, when compared to Uranus', may imply the lack of a "recent" moon-shattering event.  相似文献   

ER tubules mark sites of mitochondrial division   总被引：1，自引：0，他引：1  

Friedman JR  Lackner LL  West M  DiBenedetto JR  Nunnari J  Voeltz GK 《Science (New York, N.Y.)》2011,334(6054):358-362

Mitochondrial structure and distribution are regulated by division and fusion events. Mitochondrial division is regulated by Dnm1/Drp1, a dynamin-related protein that forms helices around mitochondria to mediate fission. Little is known about what determines sites of mitochondrial fission within the mitochondrial network. The endoplasmic reticulum (ER) and mitochondria exhibit tightly coupled dynamics and have extensive contacts. We tested whether ER plays a role in mitochondrial division. We found that mitochondrial division occurred at positions where ER tubules contacted mitochondria and mediated constriction before Drp1 recruitment. Thus, ER tubules may play an active role in defining the position of mitochondrial division sites.  相似文献   

Photometric observations of jupiter at 2400 angstroms     

Hord CW  West RA  Simmons KE  Coffeen DL  Sato M  Lane AL  Bergstralh JT 《Science (New York, N.Y.)》1979,206(4421):956-959

The photopolarimeter instrument on Voyager 2 was used to obtain a map of Jupiter at an effective wavelength of 2400 angstroms. Analysis of a typical north-south swath used to make this map shows strong absorption at high latitudes by a molecular or particulate constituent in the Jovian atmosphere. At 65 degrees north latitude, the absorbing constituent extends to altitudes above the 50-millibar pressure level.  相似文献   

Three Princes of Serendip     

West SS 《Science (New York, N.Y.)》1963,141(3584):862

  相似文献   

Analgesic management of an eight-year-old Springer Spaniel after amputation of a thoracic limb     

West E  Andreoni V  Keeley B  Self Ia  Jones B 《Irish veterinary journal》2009,62(2):111-118

Analgesic agents were administered perioperatively to an eight-year-old Springer Spaniel undergoing amputation of its right thoracic limb. The amputation was carried out due to a painful, infiltrative and poorly differentiated sarcoma involving the nerves of the brachial plexus. A combination of pre-emptive and multimodal perioperative analgesic strategies was used; including intravenous (IV) infusions of fentanyl, morphine, lidocaine and ketamine.  相似文献   

Don't go breaking apart: Anthropogenic disturbances predict meadow fragmentation of an endangered seagrass     

Daniel S. Swadling  Greg J. West  Peter T. Gibson  Roger J. Laird  Tim M. Glasby 《水产资源保护:海洋与淡水生态系统》2023,33(1):56-69

1. Although it is well established that human activities are linked to the loss of seagrasses worldwide, the influence of anthropogenic disturbances on the habitat fragmentation of seagrass meadows is less understood. This information is essential to identify how humans are modifying seascapes and what disturbances pose the greatest risk to seagrasses, which is pertinent given the rapid urbanization occurring in coastal areas.
2. This study examined how the habitat fragmentation of an endangered seagrass Posidonia australis varied in relation to several anthropogenic disturbances (i.e. human population, marine infrastructure, terrestrial run-off and catchment land-usage) within 10 estuaries across 620 km of coastline in New South Wales, Australia.
3. When comparing between estuaries, the fragmentation of P. australis meadows was significantly greater in estuaries adjacent to highly populated metropolitan centres – generally in the Greater Sydney region. At sites within estuaries, the density of boat moorings was the most important predictor of habitat fragmentation, but there was also evidence of higher fragmentation with increased numbers of jetties and oyster aquaculture leases.
4. These results suggest that the fragmentation of seagrass meadows will become more pervasive as the human population continues to grow and estuarine development increases. Strategies to mitigate anthropogenic disturbances on seagrass meadow fragmentation could include prohibiting the construction of boat moorings and other artificial structures in areas where seagrasses are present or promoting environmentally friendly designs for marine infrastructure. This knowledge will support ongoing management actions attempting to balance coastal development and the conservation of seagrasses.

  相似文献   

Land restoration management after topsoil mining and implications for restoration policy guidelines in New Zealand     

P. B. S. Hart  A. W. West  J. A. Kings  H. M. Watts  J. C. Howe 《Land Degradation \u0026amp; Development》1999,10(5):435-453

A three-year field trial on an upland loessial soil (Belmont silt loam) in New Zealand investigated the effects of ripping, application of fertilizer N and grazing management on the recovery of some physical, chemical and biochemical properties of soil and pasture productivity following removal (mining) of topsoil. Removing the top 31 cm of soil by mining (all of the A horizon and part of the AB horizon) also removed most of the soil's labile organic matter fractions, and to a lesser extent its total organic matter. After three years, the microbial C and mineralizable N in the 0–10 cm depth of mined soil had reached 65 and 62 per cent of the corresponding levels in unmined soil. Ripping to a depth of 30 cm, application of fertilizer N and lenient grazing of the pasture failed to enhance the recovery of soil fertility. A soil sampling depth of 20 cm provided a reasonable basis to assess the microbial biomass and potential fertility. Pasture productivity was, on average, 30 per cent lower on mined land than on unmined land over the first three years after mining. Application of N proved uneconomic in terms of farm production, although a good pasture response to N fertilizer was obtained. The results from this and related trials are summarized as a series of recommendations for the monitoring and regulation of topsoil mining. An incentive regime is also recommended to encourage land owners and/or topsoil miners to use successful restoration techniques on topsoil-mined land. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献