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91.
ELIZABETH K. HARPER WILLIAM J. PAUL L. DAVID MECH SANFORD WEISBERG 《The Journal of wildlife management》2008,72(3):778-784
Abstract: Wolf (Canis lupus) depredations on livestock in Minnesota, USA, are an economic problem for many livestock producers, and depredating wolves are lethally controlled. We sought to determine the effectiveness of lethal control through the analysis of data from 923 government-verified wolf depredations from 1979 to 1998. We analyzed the data by 1) assessing the correlations between the number of wolves killed in response to depredations with number of depredations the following year at state and local levels, and 2) the time to the next depredation. No analysis indicated that trapping wolves substantially reduced the following year's depredations at state or local levels. However, more specific analyses indicated that in certain situations, killing wolves was more effective than no action (i.e., not trapping). For example, trapping and killing adult males decreased the re-depredation risk. At sheep farms, killing wolves was generally effective. Attempting to trap, regardless of the results, seemed more effective at reducing depredations than not trapping, suggesting that mere human activity near depredation sites might deter future depredations. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):778–784; 2008) 相似文献
92.
RAYBURN A. LANE; AUGER JULIE A.; BENZINGER ELIZABETH A.; HEPBURN ANGUS G. 《Journal of experimental botany》1989,40(11):1179-1183
Flow cytometry was used to determine quantitative intraspecificDNA content variation in Zea mays. Previous studies using flowcytometry had indicated that intraspecific variation in cornwas beyond the resolution of the method. The DNA content variationamong corn lines observed in this study was in agreement withthe amount of variation observed using microdensitometry. Inorder to observe intraspecific variation, the fluorochrome DAPIwas shown to be superior to mithramycin. The fluorochrome: nucleiratio was found to be critical when DAPI was used because ofself absorption of the fluorescence. Flow cytometry with thefluorochrome DAPI was found to be a rapid and reliable alternativeto microdensitometry in examining intraspecific DNA contentvariation in corn. Key words: Genome size, corn (maize), Zea mays, DAPI 相似文献
93.
PETER J. DIDIER ELIZABETH S. DIDIER JAN M. ORENSTEIN JOHN A. SHADDUCK 《The Journal of eukaryotic microbiology》1991,38(5):502-507
Encephalitozoon hellem is a new human microsporidian isolated from corneal biopsies and conjunctival scrapings of three AIDS patients and cultured in Madin Darby canine kidney (MDCK) cells. Encephalitozoon hellem and Encephalitozoon cuniculi display different protein profiles with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and unique antibody binding patterns with murine antisera against Western blots of each organism. Developmental stages of E. hellem in culture are similar to E. cuniculi. Meronts are 1.3–2.7 μm in diameter, develop within a parasitophorous vacuole adjacent to the vacuolar membrane, divide by binary fission, and contain one or two discrete nuclei. Sporonts measure 2 × 3 μm, separate from the vacuolar membrane, and have a thickened outer membrane. Sporoblasts display a tri-layered wall and possess the earliest recognized polar filaments. Mature spores measure 1 × 1.5 μm and are more electron-dense than other stages. Each spore contains a single nucleus, a polar tubule with four to nine coils, thin electron-dense exospore and thick, electron-lucent endospore. Although E. hellem and E. cuniculi differ biochemically and immunologically, their fine structure and development are indistinguishable. 相似文献
94.
Do Rocks Listen? 总被引:1,自引:1,他引:0
ELIZABETH A. POVINELLI 《American anthropologist》1995,97(3):505-518
This essay attempts to show the competing cultural frameworks involved in the (e)valuation of Aboriginal work in the context of the Dreaming and development, juxtaposing Western and Belyuen ways of understanding what happens when humans act in the natural environment and their economic and politico-jural consequences. To do so, it critically opposes political-economic assumptions about the alleged divide between human subject-agents, nonintentional animal appropriators, and objects, and between cultural belief and economic-ecological reality. In this way we can begin to apprehend Aboriginal labor without aiding and abetting the state on the dispossession of Aboriginal lands and delegitimization of Aboriginal beliefs. 相似文献
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Fourcroya hunboldtiana Treal. (Agavaceae) is a rosette plantwhich accumulates fructans and shows active CAM metabolism undernatural conditions. Daily changes in titratable acidity wererelated to leaf age and degree of leaf inclination. Nocturnalacidification rates of 15 mmol H+ g1 fresh weight h1were measured under natural conditions and no recycling of respiratoryCO2 could be detected. Fructans of low molecular weight apparentlyconstituted the only source for the synthesis of substrate forCO2 fixation. Acidification was accounted for by the amountof external CO2 fixed and the reduction in fructan content duringthe night. The maximum degree of polymerization of fructansas shown by differential extraction in alcoholic solutions ofdecreasing concentration, changed during the CAM cycle, at theend of the night period maximum degree of polymerization wasaround 24, while in the late afternoon the degree of polymerizationincreased up to 43. Key words: Fourcroya humboldtiana Treal., fructans, CAM metabolism 相似文献
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EFFECTS OF SIMULATED ACIDIC RAIN ON YIELDS OF FIELD-GROWN CROPS 总被引:2,自引:2,他引:0
100.