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This article introduces latent trajectory models (LTMs), an approach often employed in social sciences to handle longitudinal data, to the arena of GIScience, particularly space‐time analysis. Using the space‐time data collected at county level for the whole United States through webpage search on the keyword “climate change,” we show that LTMs, when combined with eigenvector filtering of spatial dependence in data, are very useful in unveiling temporal trends hidden in such data: the webpage‐data derived popularity measure for climate change has been increasing from December 2011 to March 2013, but the increase rate has been slowing down. In addition, LTMs help reveal potential mechanisms behind observed space‐time trajectories through linking the webpage‐data derived popularity measure about climate change to a set of socio‐demographic covariates. Our analysis shows that controlling for population density, greater drought exposure, higher percent of people who are 16 years old or above, and higher household income are positively predictive of the trajectory slopes. Higher percentages of Republicans and number of hot days in summer are negatively related to the trajectory slopes. Implications of these results are examined, concluding with consideration of the potential utility of LTMs in space‐time analysis and more generally in GIScience.  相似文献   
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Residential field courses are important and should be designed and delivered to maximize their value to students, staff and institutions. In this context, we use a novel approach involving analysis of the daily affective and conative reflections of students immersed in the field course experience to better understand student engagement with fieldwork. We show that students base their field course choice on a range of factors (costs and benefits) and that these choices subsequently influence student expectations and motivation to engage with fieldwork. We also show that the motivation of students to engage with fieldwork-based learning varies from person to person and from day to day. Our findings suggest that having a more nuanced understanding of the decisions students make when deciding which field course to enrol upon would enhance our ability to design attractive, accessible and useful field courses; that having an awareness of the expectations of students around field courses would enable us to better prepare them to undertake them; and that students are more motivated when they are afforded an opportunity to work independently and perceive themselves to have ownership of their learning.  相似文献   
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Shortly following Canada's controversial adoption of nuclear weapon roles in NORAD and NATO in 1963, the focus of nuclear debates shifted to the potential impact on Canadian and international security of the construction of US anti-ballistic missile (ABM) systems. This article expands the focus of scholarship on the ABM issue from the political and policy-making settings to include members of the attentive elite and the news media, and finds these groups deeply divided between liberal and conservative internationalists. On the one hand, supporters of liberal internationalism believed that AMB systems would destabilise the international security environment and ultimately increase the likelihood of nuclear war. Conservative internationalists took the opposite position, arguing that the systems represented a necessary addition to the Western nuclear deterrent and would make nuclear war less likely. In other words, the ABM debate exposed deep divisions in Canadian society between those who preferred diplomatic and multilateral versus military means of achieving middle power goals in the international system.  相似文献   
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This paper examines the negative moral evaluations of people who buy and resell fresh food by Gahuku and Gehamo people in and around Goroka, the capital of Eastern Highlands Province, Papua New Guinea. During my fieldwork from 2010 to 2015, vendors in the Goroka fresh food market argued that the value of fresh food should be based on the work that people did to produce it rather than on price competition, or on supply and demand. An examination of market vendors’ practice of ‘giving extra’ to customers, and the responses of vendors who resold food to negative moral evaluations of their activities, led me to an examination of the morality of production in relation to land, ancestors, and social relations; the morality of the marketplace; as well as ideas about what makes someone a good social person. Drawing on Erik Schwimmer's (1979) discussion of the concept of work in Melanesian societies, I argue that vendors in the Goroka market continue to emphasize use value and their own identification with the food that they are selling rather than the exchange value of alienated produce. While marketplaces are the apparent locus par excellence of capitalist economic activity, a consideration of the morality of Goroka market vendors leads to the caution that just because one sees something that looks like a marketplace in which people are engaging in commodity transactions does not necessarily mean that it is a marketplace in which people are engaging in commodity transactions. Similarly, just because something looks like a price does not necessarily mean that it is a price. Those considerations, in turn, lead to a re‐examination of Kenneth Read's (1955) characterization of morality and personhood among Gahuku in light of contemporary market exchange.  相似文献   
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