旅游经济影响评估——线性规划在旅游决策中的运用

本文向旅游规划者提供线性规划模型,将其应用到国家级自然风景区--天柱山所在地潜山县,以此研究旅游发展对经济的影响,并建立一个基准水平作为比较的基础.     

Stone age predation on large African bovids

Crown height measurements are used to establish age distributions for several species of larger bovids represented in faunal samples from the Middle Stone Age (earlier Upper Pleistocene) deposits of the Klasies River Mouth Caves and the Later Stone Age (later Upper Pleistocene/Holocene) deposits of Nelson Bay Cave, South Africa. There are no obvious differences between the sites in the age distributions of the species they share, but there are significant differences in age distributions among species. Two basic patterns are apparent. In the first, characterizing the blue antelope (Hippotragus leucophaeus), roan antelope (Hippotragus equinus), Cape buffalo (Syncerus caffer), and giant buffalo (Pelorovis antiquus), the archaeological samples contain numerous very young animals and relatively few prime-age adults. At least in the buffalo samples, there is also a fair representation of old adults. In the second pattern, characterizing the bastard hartebeest (Damaliscus dorcas or D. niro) and especially of the eland (Taurotragus oryx), prime adults are far more prominent relative to younger and older age groups. The first pattern is similar to the natural pattern of attritional mortality that probably characterizes all healthy, stable populations of free-ranging large ungulates, while the second is more reminiscent of the age structure of live herds. The first pattern may reflect hunting focused on individual animals, particularly those whose age made them most vulnerable, while the second may reflect the susceptibility of certain species to driving, so that whole groups could be killed in traps in which differences in age had no meaning.