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391.
Los Angeles is often described as the epitome of urban fragmentation, a notion which in this context is frequently connected to, or even conflated with urban sprawl. At the same time, the city features integrated water and power networks which have been under public ownership for over 70 years. We thus have an apparent paradox in the context of the debate on ‘splintering urbanism’, between socio-spatial fragmentation and the integration of networks. In discussing the idea that deregulation of infrastructural networks exacerbates urban fragmentation, the authors use the case of Los Angeles in order to highlight the central role of private interests in management decisions concerning infrastructure networks. The authors carry out their analysis in an historical perspective, revealing that network integration and universal access can often serve private interests more than the public good. Urban fragmentation in Los Angeles, they conclude, is the result of a complex process of instrumentalisation of network development and management.  相似文献   
392.
A. Wendy Russell 《Geoforum》2008,39(1):213-222
In this paper, I argue that genetically modified organisms (GMOs) have inherent potential to contribute to socially and environmentally sustainable agriculture by virtue of their ‘biological embeddedness’. Their actual ‘performance’ and how this contributes to sustainability depends on the ‘mutual shaping’ of technology and context. While much attention has been given to the design context of GMOs, this paper considers the influence of the application context and of users. A case study investigating the use of insect-resistant and herbicide-tolerant GM cotton in the cotton-growing region of New South Wales in Australia is presented. The study was based on focus groups with farmers and other stakeholders in a cotton-growing community. It demonstrated a range of direct and indirect effects of GM cotton use, both positive and negative for sustainability, and the ways in which these effects were influenced by the local social context. The influences of the biotechnology industry context, in limiting the contributions that gene technologies can make to sustainability, were also considered, and remedies suggested. I argue that the polarity of the GM debate is hindering progress on these issues, and that a more balanced approach to our analysis of GMOs is necessary in order to fully understand, and to influence, their role in the future of rural spaces.  相似文献   
393.
John Law  Annemarie Mol 《Geoforum》2008,39(1):133-143
This paper is about ‘material politics’. It argues that this may be understood as a material ordering of the world in a way that contrasts this with other and equally possible alternative modes of ordering. It also suggests that while material politics may well involve words, it is not discursive in kind. This argument is made for the mundane and material practice of boiling pigswill that the 2001 UK foot and mouth outbreak showed to have a layered importance. Boiling pigswill was a political technique in at least three different ways. First it made difference, dividing the rich from the poor by separating disease free countries from those in which foot and mouth is endemic. Second, it joined times and places by linking past agricultural practices with those of the contemporary world, and linking Britain with the world. And third, it also showed a way of limiting food scarcity on a world wide scale because it allowed food to be recycled, albeit on a small scale, in a region of plenty. ‘Politics’ is often linked to debate, discussion, or explicit contestation. Alternatively, it is sometimes seen as being embedded in and carried by artefacts. For the case of boiling pigswill neither approach is satisfactory. The first privileges the life of the mind while in the second politics is linked too strongly to a single order. The version of politics presented here foregrounds both materiality and difference. And it involves articulation: the question is not whether something is political all by itself but whether it can be called political as part of the process of analysing it.  相似文献   
394.
Networking between companies and other regional key actors has grown into a widespread instrument for economic development since the 1990s. Participatory networks have formed the concept for many activities of Local Agenda 21. Simultaneously, economic geography has focused on network theories to explain innovation in and the economic success of regions.This article focuses on the reasons why individual actors participate in environmentally oriented information networks. The questions approached are: Does the concept of learning within networks influence a firm’s development? How do the participants interact with each other? What effects do the networks have on their environment (arenas)?The changing arenas of a firm are analysed with regard to environmental concerns. These changes need to be anticipated for reliable strategies. To gain information and knowledge about current behaviour and activities, the functions of networks as learning platforms are discussed. Drawing upon arguments from different network theories, the motivations of participating in a network are threefold: actor and firm oriented, network internal (inter-firm), and network external. From these, a generic target cube of network motivations and actions is set up.The concept is reviewed by examining 12 ‘regional environmental information-oriented corporation networks’ (RUN) in the Greater Munich Area. The empirical material reveals that this type of network does not provide a guarantee for significant improvements in a firm’s environmental behaviour. However, participants learn about best practices while pursuing explicit or implicit aims as to influence their arenas.  相似文献   
395.
One of Piers Blaikie’s most important contributions to the development of political ecology is his critique of land and resource conservation policy in the global South. In this paper I trace the development of Blaikie’s ideas about the policy relevance of political ecology, focusing particularly on the challenges posed by the introduction of poststructural social theory into the field. I begin by revisiting Blaikie’s earlier critiques of environment and development policy. This will provide the departure point to explore how his thinking on the relationship of theory and policy and of academic and development practices has evolved in subsequent writings. I have invented two personas, “early Blaikie” and “late Blaikie”, to facilitate this task. Second, I want to probe some of the challenges that late Blaikie presents for doing political ecology research, to some extent by pitting early Blaikie against late Blaikie and letting them hash it out. Third, I turn to my own and others’ research and consultation experiences as a way to examine the possibilities for reconciling theoretically driven critiques with policy relevant research.  相似文献   
396.
This research examines the role of social capital and networks to explain the evacuation, relocation, and recovery experiences of a Vietnamese American community in New Orleans, Louisiana in the aftermath of Hurricane Katrina. As the single largest community institution, the parish church’s complex bonding and bridging social capital and networks proved particularly critical in part because of its historically based ontological security. The process of evacuation, but especially relocation and recovery, was dependent on deploying co-ethnic social capital and networks at a variety of geographical scales. Beyond the local or community scale, extra-local, regional, and national scales of social capital and networks reproduced a spatially redefined Vietnamese American community. Part of the recovery process included constructing discursive place-based collective-action frames to successfully contest a nearby landfill that in turn engendered social capital and networks crossing ethnic boundaries to include the extra-local African American community. Engaging social capital and networks beyond the local geographical scale cultivated a Vietnamese American community with an emergent post-Katrina cultural and political identity.  相似文献   
397.
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399.
Phase equilibria simulations were performed on naturally quenchedbasaltic glasses to determine crystallization conditions priorto eruption of magmas at the Mid-Atlantic Ridge (MAR) east ofAscension Island (7–11°S). The results indicate thatmid-ocean ridge basalt (MORB) magmas beneath different segmentsof the MAR have crystallized over a wide range of pressures(100–900 MPa). However, each segment seems to have a specificcrystallization history. Nearly isobaric crystallization conditions(100–300 MPa) were obtained for the geochemically enrichedMORB magmas of the central segments, whereas normal (N)-MORBmagmas of the bounding segments are characterized by polybariccrystallization conditions (200–900 MPa). In addition,our results demonstrate close to anhydrous crystallization conditionsof N-MORBs, whereas geochemically enriched MORBs were successfullymodeled in the presence of 0·4–1 wt% H2O in theparental melts. These estimates are in agreement with direct(Fourier transform IR) measurements of H2O abundances in basalticglasses and melt inclusions for selected samples. Water contentsdetermined in the parental melts are in the range 0·04–0·09and 0·30–0·55 wt% H2O for depleted and enrichedMORBs, respectively. Our results are in general agreement (within±200 MPa) with previous approaches used to evaluate pressureestimates in MORB. However, the determination of pre-eruptiveconditions of MORBs, including temperature and water contentin addition to pressure, requires the improvement of magma crystallizationmodels to simulate liquid lines of descent in the presence ofsmall amounts of water. KEY WORDS: MORB; Mid-Atlantic Ridge; depth of crystallization; water abundances; phase equilibria calculations; cotectic crystallization; pressure estimates; polybaric fractionation  相似文献   
400.
Isotopic-geochronological study of the Pliocene magmatic activity in western part of the Dzhavakheti Highland (northwestern region of the Lesser Caucasus) is carried out. The results obtained imply that the Pliocene magmatic activity lasted in this part of the highland approximately 2 million years from 3.75 to 1.75–1.55 Ma. As is established, the studied volcanic rocks correspond in composition mostly to K-Na subalkaline and more abundant normal basalts. Time constraints of main phases in development of basic volcanism within the study region are figured out. We assume that individual pulses of silicic to moderately silicic volcanism presumably took place in the Dzhavakheti Highland about 3.2 and 2.5 Ma ago.  相似文献   
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