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231.
The clementine mission to the moon: scientific overview 总被引:4,自引:0,他引:4
Nozette S Rustan P Pleasance LP Kordas JF Lewis IT Park HS Priest RE Horan DM Regeon P Lichtenberg CL Shoemaker EM Eliason EM McEwen AS Robinson MS Spudis PD Acton CH Buratti BJ Duxbury TC Baker DN Jakosky BM Blamont JE Corson MP Resnick JH Rollins CJ Davies ME Lucey PG Malaret E Massie MA Pieters CM Reisse RA Simpson RA Smith DE Sorenson TC Breugge RW Zuber MT 《Science (New York, N.Y.)》1994,266(5192):1835-1839
In the course of 71 days in lunar orbit, from 19 February to 3 May 1994, the Clementine spacecraft acquired just under two million digital images of the moon at visible and infrared wavelengths. These data are enabling the global mapping of the rock types of the lunar crust and the first detailed investigation of the geology of the lunar polar regions and the lunar far side. In addition, laser-ranging measurements provided the first view of the global topographic figure of the moon. The topography of many ancient impact basins has been measured, and a global map of the thickness of the lunar crust has been derived from the topography and gravity. 相似文献
232.
Ascunce MS Yang CC Oakey J Calcaterra L Wu WJ Shih CJ Goudet J Ross KG Shoemaker D 《Science (New York, N.Y.)》2011,331(6020):1066-1068
The fire ant Solenopsis invicta is a significant pest that was inadvertently introduced into the southern United States almost a century ago and more recently into California and other regions of the world. An assessment of genetic variation at a diverse set of molecular markers in 2144 fire ant colonies from 75 geographic sites worldwide revealed that at least nine separate introductions of S. invicta have occurred into newly invaded areas and that the main southern U.S. population is probably the source of all but one of these introductions. The sole exception involves a putative serial invasion from the southern United States to California to Taiwan. These results illustrate in stark fashion a severe negative consequence of an increasingly massive and interconnected global trade and travel system. 相似文献
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234.
A new form of toxicity called equine fescue oedema is described. The clinical signs included inappetence, depression, and subcutaneous oedema of the head, neck, chest and abdomen. Affected horses had very low plasma albumin values. The toxicity affected 48 of 56 horses on six farms in different states of Australia, and 4 horses have died. All horses were grazing pastures that had been sown with varieties of Mediterranean tall fescue (Festuca arundinacea) that carry the endophyte known as Max P or Max Q. It is proposed that a pyrrolizidine alkaloid, N‐acetyl norloline, which is produced by the Max P endophyte, may be responsible for this new toxicity in horses. 相似文献
235.
DIDIER H. MATHON DVM PhD OLIVIER DOSSIN DVM PhD Diplomate ECVIM‐CA SOPHIE PALIERNE DVM PhD MATTHIEU CREMOUX DVM HERIBERTO RODRIGUEZ DVM PATRICIA MEYNAUD‐COLLARD DVM PhD JAN S. SUCHODOLSKI DVM PhD HERVE P. LEFEBVRE DVM PhD Diplomate ECVPT ANDRE AUTEFAGE DVM PhD Diplomate ECVS 《Veterinary surgery : VS》2009,38(8):967-974
Objective— To describe a laparoscopic‐sutured gastropexy technique in dogs and evaluate the tensile strength of the adhesion and effects on gastric function. Study Design— Experimental study. Animals— Female beagle dogs (n=7). Methods— A laparoscopic‐sutured gastropexy technique was evaluated by ex vivo tensile distraction tests 10 weeks after surgery. The effect of the adhesion on gastric emptying, mucosal permeability, and systemic inflammation were evaluated by monitoring the C‐reactive protein (CRP) and sucrose permeability, and by radiographic evaluation of gastric emptying 2 weeks before and 10 weeks after surgery. Results— Mean (±SD) tensile force to disrupt adhesions was 51.1±16.4 N. There was no significant postoperative increase in CRP concentration or change in sucrose permeability. The area under the curve representing the postprandial decrease in gastric radiographic area increased by 11% after gastropexy. Conclusions— This laparoscopic gastropexy technique had appropriate mechanical and functional characteristics with limited morbidity. Clinical Relevance— This laparoscopic‐sutured gastropexy provides adhesion strength comparable with other gastropexy techniques tested at 10 weeks postoperatively. Only minor changes in gastric emptying were observed 10 weeks after surgery. 相似文献
236.
MA Stornelli JC Reyna MC Stornelli R Nuñez Favre CA Savignone CM Tittarelli RL de la Sota 《Reproduction in domestic animals》2009,44(S2):287-290
The aim of this study was to asses the variation in the morphology of the seminal epithelium in relation to natural photoperiod in male cats. Tom cats (n = 240) were castrated every other week throughout the year. Each testis was fixed in Bouin's solution and cut into sections. The percentage of tubules with round spermatids (RS), elongated spermatids (ES), tailed spermatids (TS), mature spermatids (MS) and the number of Sertoli cells (SC) and Leydig cells (LC) were recorded in each sample. Testicles from males during short days (SHD) had a higher percentage of tubules with RS and ES compared to testicles from males during long days (LHD, 31.3 ± 0.6 vs 2.1 ± 0.6%, p < 0.001; 30.9 ± 0.7 vs 11.0 ± 0.7%, p < 0.001). Conversely, testicles from males during SHD had a lower percentage of tubules with TS and MS compared to testicles from males during LHD (24.5 ± 0.8 vs 29.7 ± 0.8%, p < 0.01; 13.1 ± 1.2 vs 57.0 ± 1.2%, p < 0.01). Furthermore, testicles from males during SHD had a higher number of SC and lower number of LC compared to testicles from males during LHD (11.4 ± 0.1 vs 8.0 ± 0.1%, p < 0.01; 19.2 ± 1.0 vs 38.0 ± 1.0%, p < 0.01). In conclusion, there are seasonal changes in testis cell morphology in the tom which may be related to seasonal sperm production. 相似文献
237.
Immunization with recombinant aerolysin and haemolysin protected channel catfish against virulent Aeromonas hydrophila
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Aeromonas hydrophila is emerging as one of the major concerns in catfish aquaculture in the Southeastern United States due to recent outbreaks of motile aeromonad septicaemia (MAS) caused by virulent clonal isolates. There is no effective vaccine currently available for the prevention of MAS. In this study, two virulence‐associated proteins of A. hydrophila, aerolysin and haemolysin, were heterologously expressed in Escherichia coli cells. Recombinant aerolysin (rArl) and haemolysin (rHly) were used to immunize catfish. Both rArl‐ and rHly‐induced humoral immune response as evidenced by immunoblotting and cell agglutination; immunized fish had significantly less mortality as compared to control fish upon challenge with virulent A. hydrophila. When a mixture of rArl and rHly was used to immunize the fish, significantly higher relative per cent survival (RPS) was obtained. Sustained RPS of 71–78% were observed at 2–5 weeks post immunization. The results of this study indicated that immunization against aerolysin and haemolysin had significant impact on the establishment of pathogenesis by A. hydrophila, suggesting that these two proteins could serve as general immunogens for future development of recombinant protein vaccines. 相似文献
238.
This study explored the existence of apoptosis (programmed cell death) in Ichthyophthirius multifiliis Fouquet (Ich) theronts and determined the effect of cutaneous antibodies in skin culture fluid from fish immune to Ich on theront apoptosis. Apoptosis was detected in theronts and was clearly distinguished by fluorescent microscopy after staining with acridine orange and propidium iodide. The apoptotic theronts showed characteristic chromatin condensation and nuclear fragments containing chromatin pieces. The externalization of phosphatidylserine on the plasma membrane of apoptotic theronts was detected with fluorescein isothiocyanate-conjugated annexin using flow cytometry. Theront apoptosis was induced using the skin culture fluid from fish immune to Ich, which contained cutaneous antibodies against Ich. The highest apoptosis appeared in theronts exposed to immune skin culture fluid at a 1:10 dilution, compared with those at 1:20 and 1:40 dilutions. A direct correlation was noted between the percentage of apoptotic theronts and exposure duration to immune skin culture fluid. The study indicated that antibody reaction with theronts (immobilization) played an important role in theront apoptosis, but it could not be excluded that other components released from the excised skin had effects on theronts. 相似文献