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A comprehensive introduction to both urban and geographical economics: the two dominant approaches used to explain the distribution of economic activity across space. This fully revised and up-to-date third edition gives a full account of the ever-expanding body of knowledge and insights on urban and geographical economics, with an increased emphasis on analytical concepts and empirical methods, reflecting developments in the literature since the last edition. The authors provide both state-of-the-art theories and empirics, introducing new data, methods and models for this edition, including a whole chapter dedicated to measurement issues and empirical methods. Written in a style that is accessible to students who are new to the field, this textbook also includes more advanced concepts that will interest experienced researchers. Unrivalled in its scope and depth, this title is perfect for readers seeking to understand the uneven spatial distribution of economic activity between and within countries.
To assess the safety against failure of rock slopes in cold regions, such as high mountain areas, where stability is potentially maintained by ice in rock discontinuities, the shear strength of ice-filled rock joints was investigated in a series of direct shear-box tests. To permit control and repeatability, the experiments were conducted using simulated rock specimens. These were cast in the laboratory using high-strength concrete. Laboratory measurements showed that at a constant rate of shearing, the interface shear strength between ice and a joint surface of repeatable roughness is a function of both temperature and normal stress.
Here we compare scaled centrifuge modelling of gelifluction processes with earlier full-scale physical modelling experiments. The objective is to assess the validity of the centrifuge technique for cryogenic slope-process investigations. Centrifuge modelling allows correct self-weight stresses to be generated within a small-scale physical model by placing it in an elevated gravitational field. This paper describes an experiment in which a scaled frozen-slope model was thawed in a gravitational field equivalent to ten gravities. After four cycles of thawing, during which soil temperatures, pore pressures, thaw settlement and downslope soil displacements were continuously monitored, a series of marker columns were excavated to reveal profiles of soil movement. Comparison of these data with those from an earlier full-scale laboratory simulation experiment indicates that thaw-related gelifluction was successfully reproduced during centrifuge modelling. It is concluded that rates of soil shear strain during gelifluction were not time-dependent? since soil displacements in the centrifuge tests were of a similar magnitude to or greater than those observed in the much longer-duration full-scale simulation. This suggests that no transition occurred in soil behaviour from a frictional plastic to a true viscous fluid during the period of high moisture contents immediately following thaw.
Soil temperatures were recorded over periods of several weeks in the years 1909 and 1970 in two sites to a depth of 100 cm. It was found that snow depth was of major importance in the rate of freezing of the soil in winter; where snow cover was less than 5 cm in depth freezing rates were almost double those where snow depth was over 1 m. Snow cover also insulated the soil surface from above-zero air temperatures during spring, and soil thawing commenced from the surface only following the clearance of snow. Similarly, insulation of the soil surface by snow prevented short-term freezing and thawing cycles penetrating the soil, although even where snow cover was absent such short-term cycles were not observed to penetrate the soil to depths in excess of 5 cm. This surficial freezing and thawing of the soil took place more readily in spring than in the autumn. It was concluded that the annual cycle of soil freezing and thawing was the dominant factor in the thermal regime of these soils, short-term freezing cycles affecting only the immediate surface soil layers.
A frozen englacial band of current-bedded silts, sands, and gravels were observed close to the snout of the temperate glacier Leirbreen. Little-disturbed sedimentary structures indicated a deltaic origin, the lack of disturbance showing that the sediments were frozen prior to their incorporation by the glacier and did not suffer shearing during glacial transport. It was concluded that they accumulated originally in a subglacial pool when the glacier was more extensive than today. Subsequent thinning of the glacier during recession allowed penetration of winter cooling to the base and freezing of subglacial sediments. The resulting layer of frozen sediment was protected from summer thawing by the overlying glacier and might therefore have been subject to further increase in thickness during successive winters. Incorporation of the frozen sediment band into the glacier resulted from compressive flow against the marginal zone of cold-based ice, leading to the development of thrust planes which penetrated through the glacier and into the frozen subglacial material. Shearing along such a thrust plane immediately below the frozen sediment layer, brought it through the glacier to the surface in a relatively undisturbed state.
Worldwide approximately 3.6 million people aged 50 and older are living and ageing with the human immunodeficiency virus (HIV). Few studies have explored successful ageing from the insider perspective of those living well and ageing with HIV. This study draws upon the lived experience and wisdom of older, HIV-positive adults living in Ontario, Canada in order to understand their views and strategies for successful ageing. This qualitative study involved semi-structured interviews with 30 individuals age 50 years and older who are HIV-positive. Purposive sampling techniques were used to recruit individuals who shared their experiences of successful ageing. Constructivist grounded theory coding techniques were used for analysis. Themes related to successful ageing included resilience strategies and challenges, social support and environmental context. Stigma and struggles to maintain health were identified as impediments to successful ageing. Models of successful ageing must take into account the potential for a subjective appraisal of success in populations suffering from chronic and life-threatening illnesses including HIV. Practitioners can draw upon organically existent strengths in this population in order to provide intervention development for older adults around the world who are struggling to manage their HIV.
Indigenous Studies is a rapidly growing field of enquiry both nationally and internationally. The internationalisation of the discipline is dependent on its interdiciplinarity and on the collaborative efforts of interdisciplinary scholars. Colonised Indigenous people globally share similar experiences despite differences in histories and contexts. In collaborative situations, dedicated scholarship brings together Indigenous people and allies who are committed to the global expansion of Indigenous knowledge through shared understandings of experiences and histories. Collective efforts can improve curriculum development, enhance opportunities for publication, bring scholars together in conferences and symposia and provide opportunities for new research networks for Indigenous scholarship. This paper addresses spheres of collaborative and collective endeavours that continue to reap benefits nationally and internationally in the field of international Indigenous Studies.
Beaches and dunes of the open coast form one of the globe’s longest ecological interfaces, linking the oceans with the land. These systems are of great importance to society as prime sites for housing and recreation, buffers against storms, and providers of fisheries and mineral resources. By contrast, their unique ecological attributes and biodiversity are much less recognized. In this chapter, we provide a synthesis of the key ecological features and functions of beaches and dunes, outline the main elements of their faunal biodiversity, examine human threats and their biological consequences, and sketch some salient issues in management to achieve conservation of these unique ecosystems. It is apparent that the range of ecosystem goods and services is broad, but nutrient cycling, water filtration, and the provision of habitat and prey for a diverse range of animals are often the key ecological traits. Contrary to common perceptions, beaches and dunes contain a diverse and unique set of species, many of which are found nowhere else. In addition to the complement of highly adapted invertebrates, many wildlife species (e.g. birds, turtles, fishes) are dependent on beaches and dunes for nesting and feeding, and they use these habitats extensively. Human pressures on sandy shorelines and their biodiversity are numerous. Coastal squeeze is, however, the most pervasive, trapping beaches and their biota between the pressures of development from the terrestrial side and the consequences of climate change from the marine side. Beaches are also naturally malleable habitats whose interlinkages, including the exchange of organisms, with the abutting dunes and surf zones are essential to their functioning. Unfortunately, human actions intended to arrest the dynamics of beach habitats, such as seawalls and dune stabilizations, run counter to these natural dynamics and generally produce negative environmental outcomes. These present a set of formidable management challenges when the primary goal is to conserve intact ecosystems and biodiversity, calling for more systematic approaches in conservation design and implementation for beach and dune ecosystems.
This indispensable sourcebook covers conceptual and practical issues in research design in the field of social and personality psychology. Key experts address specific methods and areas of research, contributing to a comprehensive overview of contemporary practice. This updated and expanded second edition offers current commentary on social and personality psychology, reflecting the rapid development of this dynamic area of research over the past decade. With the help of this up-to-date text, both seasoned and beginning social psychologists will be able to explore the various tools and methods available to them in their research as they craft experiments and imagine new methodological possibilities.