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Compared to the geographic wasteland south of your border, geography appears to have fared well in Canada, both as a formal discipline extending our understanding by illuminating the human and physical worlds, and as a subject taught at all levels to create informed and aware citizens. I known you think much remains to be done, and perhaps things always look a bit greener on the other side of the hill, but I hope you will not mind my somewhat envious gaze. In fact, when I received the five volumes of the 'curriculum guideline' for geography, issued by the Ontario Ministry of Education for the intermediate and senior divisions of your high schools (ome 1988), my feelings were not so much envy as panic, a panic that rapidly induced something close to intellectual paralysis. Because in a moment I can only describe now as utterly weak and foolish, I started to read them, only to learn that your senior students 'analyze, interpret … explain … design and develop networks, systems and simulations that involve six or more variables' (ome 1988, A12).
In retrospect, I still think my panic was justified. After 30 years of hard post-doctoral work I have reached the point where I can think about the interactions of maybe three variables, but hardly the combinatorial possibilities of six. Such ineptness would mean that I might just squeeze into your tenth grade and from there slowly work my way over the next two years towards those Olympian heights of analytical thought where dwell Ontario's high school graduates.  相似文献   
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This paper extends a compartmental epidemiological model for HIV transmission and AIDS incidence to include hierarchical and expansion spatial diffusion. An implication of the resultant model is that hierarchical diffusion causes the large infection growth rates of densely populated areas at the top of the central places hierarchy to “chain” down and dominate small local growth rates during the exponential-growth phase of the epidemic. Also, hierarchical diffusion causes a high transient growth rate in the first few years of a local epidemic. The spatial compartmental model fits observed AIDS incidence spatial diffusion patterns in Ohio reasonably well.  相似文献   
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What was the extent of marital breakdown and separation in a society where divorce was unlikely to be an option? This article investigates the status and longevity of the marriages of a group of parents whose children were admitted to the care of the poor law authorities in Camberwell in the latter part of the nineteenth century. It finds that spousal death or misfortune, rather than marital breakdown, were the primary reasons for a parent to send a child to the poor law authorities, and that most of the marriages of the parents in the sample remained intact. It also explores whether those who separated formed new co-residential relationships.  相似文献   
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The sixteenth‐century Shebet Yehudah is an account of the persecutions of Jews in various countries and epochs, including their expulsion from Spain in the fifteenth century. It is not a medieval text and was written long after many of the events it describes. Yet although it cannot give us a contemporary medieval standpoint, it provides important insights into how later Jewish writers perceived Jewish–papal relations in the thirteenth, fourteenth, and fifteenth centuries. Although the extent to which Jewish communities came into contact either with the papacy as an institution or the actions of individual popes varied immensely, it is through analysis of Hebrew works such as the Shebet Yehudah that we are able to piece together a certain understanding of Jewish ideas about the medieval papacy as an institution and the policies of individual popes. This article argues that Jews knew only too well that papal protection was not unlimited, but always carefully circumscribed in accordance with Christian theology. It is hoped that it will be a scholarly contribution to our growing understanding of Jewish ideas about the papacy's spiritual and temporal power and authority in the Later Middle Ages and how this impacted on Jewish communities throughout medieval Europe.  相似文献   
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A high-resolution chronostratigraphy has been established for an eroding Atlantic round house at Sloc Sàbhaidh (North Uist, Scotland), combining detailed OSL profiling and dating of sediments encompassing the main bracketing events associated with the monument, radiocarbon AMS dates on bone recovered from excavated features and fills within it, and TL dates on pottery and burnt clay. Concordant OSL and radiocarbon evidence place construction of the wheelhouse in the first to second centuries AD, contemporary with dates from the primary occupation. Beneath the wheelhouse, clay deposits containing burnt material, attest to cultural activity in vicinity to the monument in the preceding second to first centuries BC. At a later date, the southern wall collapsed, was rebuilt, and the interior spaces to the monument re-structured. The chronology for the later horizons identified from the sediment luminescence dates extends to the second half of the first millennium AD, which goes beyond the range of the radiocarbon dates obtained. The data from ceramics encompass both periods. The juxtaposition of the dating evidence is discussed relative to short and longer chronologies for this Iron Age monument. Corollaries of this research are the implications that based on the long chronology, some of the ecofacts (bone) appear to be residual, and that the temporal duration of Hebridean Coarse Ware may extend into the second half of the first millennium AD.  相似文献   
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