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61.
The rate at which epidemics of zoonotic disease in humans have surfaced over the past 25 years has shaken--some would say shattered--the assumption that zoonotic diseases are under control, says Paul Gibbs. In this review he analyses the global factors that have led to the increased emergence of zoonotic diseases, sketches several recent epidemics (and where relevant, their relationship to bioterrorism), discusses the lessons learned, and concludes by outlining an agenda for action.  相似文献   
62.
The use of contrast medium in the examination of the gastrointestinal tract is described and some aspects of the normal radiographic anatomy are discussed. The radiological features of certain conditions causing gastrointestinal obstruction are illustrated by a series of radiographs. Résumé. On décrit l'usage de substance de contraste dans l'exploration des voies gastro-intestinales, et on discute de certaines aspects de l'anatomie radiographique normale. Les caractéristiques radiologiques de certaines particularités causant une obstruction gastro-intestinale sont illustrées au moyen d'une série de radiographies. Zusammenfassung. Der Gebrauch von Kontrastmitteln in der Untersuchung des Verdauungskanal ist beschrieben und einige Aspekte von der normalen röntgenologischen Anatomie sind diskutiert. Die radiologischen Merkmale von gewissen Zuständen die gastrointestinale Obstruktion verursachen, sind in einer Serie vom Röntgenaufnahmen illustriert.  相似文献   
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Energy is an essential nutrient for all horses, and it is especially important in performance horses, pregnant and lactating mares, and young growing horses. A negative energy balance in horses such as these may result in unsatisfactory performance, decreased fertility, or slow growth. Therefore, ensuring adequate energy intake is an important aspect of the nutritional management of the equine. This study was undertaken to investigate the effects of feeding large, carbohydrate-rich, concentrate meals on the satiety-inducing hormone, leptin. Three groups of yearling horses were rotated through 3 feeding schedules in a replicated 3x3 Latin square design. Horses were fed 2, 3, or 4 times per day (2x, 3x, and 4xfeeding schedules, respectively), each for a period of 11 d, with the total amount of daily feed held constant. Horses were weighed and BCS was determined on the first day of each period. Blood samples were collected before the morning meal on d 1, 4, and 7 of each period. Additionally, blood was sampled for the last 24 h of the 2xand 4xdietary periods. Neither weight nor BCS changed during the study (P = 0.99 and P = 0.28, respectively). Both mean and peak plasma glucose were greatest in 2xhorses (P < 0.05), as were mean areas under the curve. Serum leptin concentration increased in 2xhorses (P < 0.05), but not in horses fed 3 or 4 times daily. Leptin was elevated in horses with greater BCS (P < 0.05) and increased steadily throughout the study (P < 0.05). Data from the 24-h collection indicated that 2xhorses had fluctuations in leptin production throughout the day (P < 0.05), whereas horses fed 4 times daily did not. Overall, this study indicates that feeding horses 2 large concentrate meals daily can increase mean serum leptin concentrations and may cause fluctuations in leptin production over a 24-h period. This departure from baseline leptin concentration has the potential to affect appetite, along with numerous other physiological processes.  相似文献   
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The Paleocene-Eocene Thermal Maximum (PETM, approximately 55 million years ago) was an interval of global warming and ocean acidification attributed to rapid release and oxidation of buried carbon. We show that the onset of the PETM coincided with a prominent increase in the origination and extinction of calcareous phytoplankton. Yet major perturbation of the surface-water saturation state across the PETM was not detrimental to the survival of most calcareous nannoplankton taxa and did not impart a calcification or ecological bias to the pattern of evolutionary turnover. Instead, the rate of environmental change appears to have driven turnover, preferentially affecting rare taxa living close to their viable limits.  相似文献   
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