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Extensive examination of large numbers of spatially orientated thin sections of orientated samples from orogens of all ages around the world has demonstrated that porphyroblasts do not rotate relative to geographical coordinates during highly non-coaxial ductile deformation of the matrix subsequent to their growth. This has been demonstrated for all tectonic environments so far investigated. The work also has provided new insights and data on metamorphic, structural and tectonic processes including: (1) the intimate control of deformation partitioning on metamorphic reactions; (2) solutions to the lack of correlation between lineations that indicate the direction of movement within thrusts and shear zones, and relative plate motion; and (3) a possible technique for determining the direction of relative plate motion that caused orogenesis in ancient orogens.  相似文献   
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Local geography and gender are two major factors determining which crop varieties are cultivated in a case study of two rural villages in Bangladesh. This paper explores the interrelationships between gender, agrobiodiversity, and the use of, and preferences for, improved and local crop varieties. These are examined in relation to rice, minor field crops, and home garden fruits and vegetables. Reasons for both the displacement and the persistence of local varieties (LVs) are analysed in comparison to improved variety (IV) diffusion. The research evaluates agrobiodiversity through the number, types, and varieties of crops grown in fields and home gardens. The desired agroecological, economic, and cultural characteristics of crops grown document how respondents rank their variety preferences. Variety preferences and the perceived importance of LV preservation are compared with what is actually grown. The study indicates that there was little variation between villages in their approach towards the use of IV and LV rice; IVs were cultivated for their high yields and LV rice for taste and culinary uses. However, there were significant differences in relative agricultural dependence between the two villages which led to unique variety preferences. In both villages, women's preferences for IVs or LVs play a major role in crop choices, particularly as they manifest themselves in gendered domains of authority.  相似文献   
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A narrow line of convective showers was observed over southern England on 18 July 2005 during the Convective Storm Initiation Project (CSIP). The showers formed behind a cold front (CF), beneath two apparently descending dry layers (i.e. sloping so that they descended relative to the instruments observing them). The lowermost dry layer was associated with a tropopause fold from a depression, which formed 2 d earlier from a breaking Rossby wave, located northwest of the UK. The uppermost dry layer had fragmented from the original streamer due to rotation around the depression (This rotation was also responsible for the observations of apparent descent—ascent would otherwise be seen behind a CF). The lowermost dry layer descended over the UK and overran higher  θ w   air beneath it, resulting in potential instability. Combined with a surface convergence line (which triggered the convection but had less impact on the convective available potential energy than the potential instability), convection was forced up to 5.5 km where the uppermost dry layer capped it. The period when convection was possible was very short, thus explaining the narrowness of the shower band. Convective Storm Initiation Project observations and model data are presented to illustrate the unique processes in this case.  相似文献   
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ABSTRACT. In an effort to provide a more complex and multifaceted understanding of the process of spatial assimilation, this article explores alternative paths in understanding racial/ ethnic minority residential patterns. It scrutinizes patterns of contemporary Asian Indian and Chinese settlement in two metropolitan areas: Austin, Texas and Phoenix, Arizona. Though not particularly evolved in terms of their Asian immigrant settlement or dynamics, Austin and Phoenix represent the growing number of newly emergent Asian centers throughout the nation that have developed with the rapid rise of immigration from these two countries in the past several decades. The analysis utilizes records from the 2000 census to document and map Asian Indian and Chinese settlement within each metropolitan area and to investigate whether‐and to what degree‐each group is clustered or dispersed. The article then raises important questions about the consequences of concentration and dispersal for the incorporation of Asian Indian and Chinese residents.  相似文献   
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ABSTRACT. It is increasingly clear that local participation in conservation endeavors is not only critical but also highly problematic. El VizcaÍno Biosphere Reserve in Baja California Sur, Mexico, is examined to study the difficulties involved in translating community-based conservation rhetoric into on-the-ground nature-protection efforts. This case illustrates how inhabitants of a reserve are marginalized by the very conservation process meant to engage them as key actors in promoting natural-resource protection. It also highlights recent attempts to enhance local participation in reserve endeavors through collaborative efforts among field staff, nongovernmental organizations, and area residents.  相似文献   
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Collecting geological information from the jungles and islands of eastern Indonesia depends largely on traditional fieldwork methods involving much footwork and messing about in boats. Coupled with modern laboratory and computing techniques, information gained on the ground is being used to interpret the tectonic development of east Indonesia, the Philippine Sea and the western Pacific.  相似文献   
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ABSTRACT. Miami is the primate city in a system of urban settlements that make up a Cuban ethnic archipelago in the United States. The city is also a national magnet, attracting Cuban migrants from metropolitan regions across the archipelago. Four large secondary cores of Cubans outside Florida serve as major “feeders” to the Miami enclave: northern New Jersey, New York City, Los Angeles, and Chicago. Currents of migration to Miami are especially strong among older, foreign-born, and disadvantaged Cubans, an indication of segmented paths in Cuban assimilation. Although concentration in Metropolitan Miami has been the Cuban story over the past three decades, processes of deconcentration now may well be under way.  相似文献   
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