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Palaeoanthropologists and archaeologists have advanced a wide range of explanatory narratives for the various movements of Homo erectus/Homo ergaster, and the first modern Homo sapiens, “Out of Africa”—or even back again. The application of Occam's razor—a parsimonious approach to causes—gives a more cautious approach. There is nothing in the available evidence that would require the ability for a human water crossing from Africa before the later Pleistocene, whether across the Strait of Gibraltar, the Sicilian Channel or the southern Red Sea (Bab el-Mandab). A parsimonious narrative is consistent with movements across the Sinai peninsula. The continuous arid zone from northern Africa to western Asia allowed both occupation and transit during wet phases of the Pleistocene; there is no requirement for a “sponge” model of absorption followed by expulsion of human groups. The Nile Valley as a possible transit route from East Africa has a geological chronology that could fit well much current evidence for the timing of human migration. The limited spatial and temporal opportunities for movements “Out of Africa,” or back again, also puts particular difficulties in the way of the gene flow required for the multiregional hypothesis of the development of modern Homo sapiens. 相似文献
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Parking coupon programs help downtown shopping areas attract consumers away from suburban shopping centers. Here we conduct an empirical analysis of retailer participation in such a program. Consistent with expectations, participation was higher for stores in shopping centers than for street-front retailers, for stores receiving subsidies for coupon purchase, and for stores selling comparison-shopping goods than for stores selling goods bought on one-stop, single-purpose or multipurpose-shopping trips. Participation also varied with numbers of competitors, chain membership, and store vintage. Apparently, participation is a local public good for downtown retailers and stores are inclined to free ride. 相似文献
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Robin Bates 《American Nineteenth Century History》2016,17(1):23-41
For more than half a century, the Robert E. Lee Camp Soldiers' Home in Richmond, Virginia, provided shelter, food, and medical care to some of the South's neediest Confederate veterans. Applications to the Lee Camp home offer valuable insight into the post-war experiences of a substantial number of Confederate veterans and highlight the enduring effects of the Civil War upon those who fought in it. For such men, the long-term physical and economic ramifications of the conflict largely exceeded the capabilities of existing avenues of social assistance and necessitated the augmentation of state-based welfare efforts. Moreover, applications to the Lee Camp soldiers' home indicate some of the cultural assumptions which informed the home's application process and demonstrate the duality of purpose that has often been regarded by historians as a key characteristic of Confederate veterans' welfare. 相似文献
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