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Garzione CN Hoke GD Libarkin JC Withers S MacFadden B Eiler J Ghosh P Mulch A 《Science (New York, N.Y.)》2008,320(5881):1304-1307
The surface uplift of mountain belts is generally assumed to reflect progressive shortening and crustal thickening, leading to their gradual rise. Recent studies of the Andes indicate that their elevation remained relatively stable for long periods (tens of millions of years), separated by rapid (1 to 4 million years) changes of 1.5 kilometers or more. Periodic punctuated surface uplift of mountain belts probably reflects the rapid removal of unstable, dense lower lithosphere after long-term thickening of the crust and lithospheric mantle. 相似文献
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Anthony T. Blikslager DVM Eleanor M. Green DVM Karen E. MacFadden DVM Bennett Fagin DVM Gayle C. Johnson DVM PhD 《Veterinary radiology & ultrasound》1992,33(1):41-47
A 7-week-old Appaloosa filly was admitted for persistent urinary incontinence since birth. Vaginal speculum examination revealed urine flowing from an opening in the right vaginal wall. Cystoscopy demonstrated that the ureters did not terminate at the bladder. The endoscope passed easily from the vagina directly into a dilated right ureter. An excretory urogram confirmed the vaginal termination of at least one ureter, based upon extensive filling of the vagina with contrast media in the absence of bladder filling. Bilateral hydroureter and dilated renal pelves were demonstrated both by excretory urography and by ultrasonography. Euthanasia was requested by the owner in lieu of attempted surgical correction. At necropsy, it was confirmed that the right ureter entered the vagina and the left ureter terminated at the urethra. The diagnosis of bilateral ectopic ureter in this foal was suggested by the history and clinical signs, supported by endoscopy and ultrasonography, and confirmed by excretory urography and necropsy. This case establishes the value of diagnostic imaging techniques in the antemortem diagnosis of ectopic ureter. 相似文献
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Six sympatric species of 5-million-year-old (late Hemphillian) horses from Florida existed during a time of major global change and extinction in terrestrial ecosystems. Traditionally, these horses were interpreted to have fed on abrasive grasses because of their high-crowned teeth. However, carbon isotopic and tooth microwear data indicate that these horses were not all C4 grazers but also included mixed feeders and C3 browsers. The late Hemphillian Florida sister species of the modern genus Equus was principally a browser, unlike the grazing diet of modern equids. Late Hemphillian horse extinctions in Florida involved two grazing and one browsing species. 相似文献
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David A. Wilson Karen E. MacFadden Eleanor M. Green Mark Crabill Rebecca L. Frankeny James G. Thorne 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1996,10(4):258-264
Trimethoprim-potentiated sulphonamides (TPS) are among the most frequently administered antimicrobials in equine medicine. Anecdotally, TPS has been implicated as a cause of mild to moderate diarrhea in horses. The purpose of this study was to document the prevalence of diarrhea in horses receiving TPS, to characterize the severity of the diarrhea, and to identify any other factors associated with the development of diarrhea. A 2–part study was designed to identify the prevalence of diarrhea associated with TPS in our clinic population. Part I was a case-control retrospective study of 135 records over a 10.5–year period from January 1, 1980 through June 30, 1990. Part II was a historical cohort study of 784 records over a 37–month period from July 1, 1990 through July 31, 1993. There was no significant difference in the occurrence of diarrhea associated with TPS therapy in either study. The occurrence of diarrhea was 21% and 3% in parts I and II, respectively. Significant factors identified in association with diarrhea in part I were duration of hospital stay, and antibiotic therapy other than TPS or penicillin. Significant factors identified in part II included other antibiotic therapy, penicillin therapy, and combined penicillin and TPS therapy. Diarrhea does occur after the administration of antibiotics, most likely because of the alteration of the patient's normal intestinal flora. Diarrhea was noted in association with administration of TPS in this study; however, its prevalence was not significantly different than that in horses receiving other antibiotics, such as penicillin and its derivatives. J Vet Intern Med 1996;10:258–264. Copyright © 1996 by the American College of Veterinary Internal Medicine . 相似文献
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A T Blikslager D A Wilson D S Taylor K E MacFadden J R Fischer W H Fales 《Journal of the American Veterinary Medical Association》1991,199(12):1757-1759
An 11-year-old, 430-kg fox-trotter stallion was referred for evaluation of colic. A right-sided inguinal hernia was diagnosed. At exploratory laparotomy, the ileum was found to be herniated through the right inguinal canal. Compromised small intestine was resected, jejunocecal anastomosis was performed, and the horse was castrated. Three days after surgery, the stallion would not bear weight on the left hind limb. The musculature of the left thigh region became swollen. Aspiration of the left thigh region yielded serosanguineous fluid from which Salmonella typhimurium was isolated. Ultrasonography of the left thigh revealed multiple hypoechoic areas suggestive of abscess. The left medial thigh region was surgically incised, and a large abscess was drained. Bacteriologic culture of feces yielded S typhimurium. The owner elected to have the horse euthanatized. 相似文献
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