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911.
912.
Marion Valeix Hervé Fritz Rodolphe Sabatier Felix Murindagomo David Cumming Patrick Duncan 《Biological conservation》2011,(2):902-912
African elephants can affect the quality of the habitat of other species by breaking or uprooting trees and shrubs in savannas. Their effect on vegetation has been widely studied but less is known about the effects of such vegetation changes on other animals. We studied how changes in the vegetation caused by elephants influence the selection of microhabitats by five African herbivore species (giraffe, kudu, steenbok, impala, and zebra) in Hwange National Park, Zimbabwe. There was no clear significant effect of overall elephant-induced vegetation changes on microhabitat selection except for the small species (steenbok and impala) that used vegetation modified by elephants preferentially. This is consistent with a medium-term browsing facilitation hypothesis. More subtle possible effects were detected for larger browsers (giraffe and kudu). They selected areas with broken and uprooted plants and avoided coppiced areas. All of the browsers selected sites characterized by plants uprooted and broken by elephants, which were associated with a higher visibility, and ultimately a better probability of detecting an approaching predator, suggesting that perceived predation risk plays an important role in microhabitat selection. These results illustrate how elephants can initiate indirect effects that influence microhabitat selection by other herbivores. Understanding the indirect effects of elephants through changes in food availability and predation risk thus needs further investigation. The results of this study do not provide support for the hypothesis that elephant-induced changes in the structure of habitats have caused the declines in the populations of the other herbivores in the study area. 相似文献
913.
914.
915.
浅析江苏省农业科学院溧水植物科学基地休闲观光功能 总被引:1,自引:0,他引:1
根据江苏省农科院溧水植物科学基地的资源条件,以及近年来的运行情况,分析拓展其功能定位中的休闲观光功能的利弊因素,提出应对策略,以期进一步拓展基地的休闲观光功能,满足广大市民对回归自然的需求,实现基地经济和社会效益的双赢。 相似文献
916.
针对现行检测站的台架试验检测无法真实地反映其制动性能,而道路试验的随机性大、重复性较差等问题.在理论分析的基础上建立ABS汽车的制动性能检测结果的区间函数,结合高速道路试验,对其结果进行评价.结果表明:该方法能大大地减少道路试验的随机性.并能可靠地对ABS汽车的制动性能进行评价. 相似文献
917.
Naglaa Abdel Megid Gomaa BVSc MVSc Gábor Köller Dr rer nat Gerald Fritz Schusser Dr vet med DECEIM 《Journal of Veterinary Emergency and Critical Care》2011,21(3):242-252
Objectives – To measure serum alcohol dehydrogenase (ADH) activity in horses with acute intestinal obstruction and to determine the diagnostic and prognostic utility of this analyte. Design – Prospective observational study. Setting – University Veterinary Hospital. Animals – Thirty healthy horses (control group) and 77 horses with acute intestinal obstruction, including 36 horses with nonstrangulating obstruction (23 with left ventral colon impaction and 13 with left dorsal displacement [G1], 22 with small intestinal strangulation [G2], and 19 with colon torsion [G3]). Interventions – Serum ADH activity was assayed spectrophotometerically in all horses. Serum lactate concentration and hepatic enzyme (aspartate aminotransferase, gamma‐glutamyl transferase, glutamate dehydrogenase) activities were measured using an automatic analyzer. Measurements and Main Results – The median [interquartile range] serum ADH activity in healthy horses was 10.5 [8.7 – 11 U/L]. ADH activity was significantly increased (P<0.05) in G1=16.5 [13.8 – 18 U/L], G2=40 [20 – 74.9 U/L], and G3=63.2 [40 – 78 U/L] compared with healthy controls. Aspartate aminotransferase and glutamate dehydrogenase activities were also significantly increased in G3 in comparison with controls. ADH activity was correlated with serum lactate concentration in G1 and G3, respectively (P<0.01, r=0.55 and 0.8). Other liver enzymes did not show any significant correlation with lactate. ADH activity was directly related to the probability of strangulation; odds ratio=1.11. ADH activity >20 U/L had 80.6% specificity and 80.5% sensitivity for discriminating horses with strangulating obstruction. Twelve horses euthanized before surgery were excluded from the outcome analysis. Increasing ADH activity was associated with nonsurvival; odds ratio=1.03. ADH activity <80 U/L had 94.44% specificity and 66.67% sensitivity for survival. Conclusion – Serum ADH activity may be a useful clinical parameter in detecting intestinal strangulation in horses and may provide some prognostic value in horses with acute intestinal obstruction. 相似文献
918.
The goal of this study was to determine the efficacy and tolerability of gemcitabine in dogs diagnosed with hepatocellular carcinoma (HCC). Eighteen dogs were examined retrospectively (4 massive HCC, 10 nodular HCC and 4 diffuse HCC). All dogs received gemcitabine at 350-400 mg m(-2) weekly for 5 weeks. Toxicity was graded using VCOG-CTCAE guidelines and response was monitored with serial abdominal ultrasounds. Fifteen dogs completed all five cycles. Toxicity was minimal and consisted of grade I/II vomiting, anorexia and diarrhoea and two episodes of grade III neutropenia. Median survival time for all dogs was 983 days. Median progression free interval was 971 days. Based on the results of this study, surgery remains the best treatment for HCC, despite incomplete resection. There was no improvement in the survival of those diagnosed with nonresectable HCC treated with gemcitabine chemotherapy. 相似文献
919.
920.