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121.
Kate Day  Paul White 《GeoJournal》2002,56(1):15-26
Questions concerning why asylum seekers make their applications in particular countries rather than others have not been fully researched. Some explanation can be found via aggregate migration theories, but there is a need to consider the circumstances of individual movers. Respondents here were drawn from amongst Bosnian and Somali refugees in northern England. The interviews showed that asylum movement is of a variety of types, with two stage migration commonly involved – firstly immediate flight to a neighbouring haven, and secondly on to a more permanent place of settlement. Very few respondents had any real choice in where they ended up. Instead, family circumstances, cultural connections, and the actions of a variety of institutions produced scenarios in which there was generally no alternative to the actual destination arrived at. It is suggested that a mix of individual level and institutional explanations is needed to understand patterns of asylum destinations. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
122.
Smith  Kate R.  Grant  Silvia  Thomas  Robert E. 《Natural Hazards》2022,112(2):1611-1631
Natural Hazards - European Governments must implement a public alerting system to reach mobile phone users affected by major emergencies and disasters by June 2022. Cell Broadcast is used to issue...  相似文献   
123.
This paper describes two projects requiring production of national floodplain maps for England and Wales – some 80,000 km of river. The novel solutions developed have brought together a national Digital Elevation Model (DEM), automatically-generated peak flow estimates at intervals along the watercourses and two alternative methods of calculating the outlines: normal depth calculation; and a purpose-built 2-dimensional raster-based floodplain model, JFLOW. The DEM was derived using Interferometric Synthetic Aperture Radar (IFSAR) techniques and has a vertical precision of ±0.5 m–1.0 m (RMSE) and a 5 m horizontal resolution. The flow estimates were derived by automating Flood Estimation Handbook (FEH) techniques. The normal depth calculations are applied at a number of discrete cross-sections with linear interpolation between to form a 3-dimensional water surface. This is overlain on the DEM to produce the flood outline. Careful manual checking is required at a number of stages. The JFLOW model is based on a discretised form of the 2-dimensional diffusive wave equation and directly simulates the flood outline in a series of overlapping short (1 km) reaches. Flood outlines from the overlapping reaches are merged to produce the overall flood envelope. The model has been written to work as a screen-saver, allowing distributed processing across all computers in an office and manual intervention is minimal. In simple valley situations both methods give similar results, but show differences in more complex areas. Each has advantages and disadvantages, but both have been shown to be a practicable solution to allow production of 160,000 km of flood outline in 12 months.  相似文献   
124.
The availability of dissolved O2 can limit biodegradation of organic compounds in aquifers. Where O2 is depleted, biodegradation proceeds via anaerobic processes, including NO3-, Mn(IV)-, Fe(III)- and SO4-reduction and fermentation/methanogenesis. The environmental controls on these anaerobic processes must be understood to support implementation of management strategies such as monitored natural attenuation (MNA). In this study stable isotope analysis is used to show that the relative significance of two key anaerobic biodegradation processes (bacterial SO4 reduction (BSR) and methanogenesis) in a phenol-contaminated sandstone aquifer is sensitive to spatial and temporal changes in total dissolved phenols concentration (TPC) (= phenol + cresols + dimethylphenols) over a 5-a period. In general, 34SO4-enrichment (characteristic of bacterial SO4 reduction) is restricted spatially to locations where TPC < 2000 mg L−1. In contrast, 13C-depleted CH4 and 13C-enriched CO2 isotope compositions (characteristic of methanogenesis) were measured at TPC up to 8000 mg L−1. This is consistent with previous studies that demonstrate suppression of BSR at TPC of >500 mg L−1, and suggests that methanogenic microorganisms may have a higher tolerance for TPC in this contaminant plume. It is concluded that isotopic enrichment trends can be used to identify conditions under which in situ biodegradation may be limited by the properties of the biodegradation substrate (in this case TPC). Such data may be used to deduce the performance of MNA for contaminated groundwater in similar settings.  相似文献   
125.
Hydrogeology Journal - In the High Plains (HP) region of northeastern New Mexico (NE NM), USA, underlying bedrock aquifers are utilized where the High Plains Aquifer is thin, absent, or...  相似文献   
126.
Human activities on coastal watersheds provide the major sources of nutrients entering shallow coastal ecosystems. Nutrient loadings from watersheds are the most widespread factor that alters structure and function of receiving aquatic ecosystems. To investigate this coupling of land to marine systems, we are studying a series of subwatersheds of Waquoit Bay that differ in degree of urbanization and hence are exposed to widely different nutrient loading rates. The subwatersheds differ in the number of septic tanks and the relative acreage of forests. In the area of our study, groundwater is the major mechanism that transports nutrients to coastal waters. Although there is some attenuation of nutrient concentrations within the aquifer or at the sediment-water interface, in urbanized areas there are significant increases in the nutrient content of groundwater arriving at the shore’s edge. The groundwater seeps or flows through the sediment-water boundary, and sufficient groundwater-borne nutrients (nitrogen in particular) traverse the sediment-water boundary to cause significant changes in the aquatic ecosystem. These loading-dependent alterations include increased nutrients in water, greater primary production by phytoplankton, and increased macroaglal biomass and growth (mediated by a suite of physiological responses to abundance of nutrients). The increased macroalgal biomass dominates the bay ecosystem through second- or third-order effects such as alterations of nutrient status of water columns and increasing frequency of anoxic events. The increases in seaweeds have decreased the areas covered by eelgrass habitats. The change in habitat type, plus the increased frequency of anoxic events, change the composition of the benthic fauna. The data make evident the importance of bottom-up control in shallow coastal food webs. The coupling of land to sea by groundwater-borne nutrient transport is mediated by a complex series of steps; the cascade of processes make it unlikely to find a one-to-one relation between land use and conditions in the aquatic ecosystem. Study of the process and synthesis by appropriate models may provide a way to deal with the complexities of the coupling.  相似文献   
127.
Deposits of the 22.6 ka Okareka Eruption Episode from Tarawera Volcanic Complex record the sequential and simultaneous eruption of three discrete rhyolite magmas following a silicic recharge event related to basaltic intrusion. The episode started with basaltic eruption ( 0.01 km3 magma), and rapidly changed to a plinian eruption involving a moderate temperature (750 °C), cummingtonite-bearing rhyolite magma (T1) with a volume of  0.3 km3. Hybrid basalt/rhyolite clasts demonstrate direct basaltic intrusion that helped trigger the eruption. Crystals, shards and lapilli of two other rhyolite magmas then joined the eruption sequence. They comprise a cooler (720 °C) crystal-rich biotite–hornblende rhyolite magma (T2) ( 0.3 km3), and a hotter (780 °C), crystal-poor, pyroxene–hornblende rhyolite magma (T3) ( 4.5 km3). All mid to late-stage ash units contain various mixtures of T1, T2 and T3 components with a general increase in abundance of T3 and rapid decline of T1 with time. About 4 km3 of T3 magma was extruded as lavas at the end of the episode. Contrasts in melt composition, crystal and volatile contents, and temperatures influenced viscosity and miscibility, and thus limited pre-eruption mixing of the rhyolite magmas. The eruption sequence and the restricted direct basaltic intrusion into only one magma (T1) is consistent with the rhyolites occupying separate melt pods within a large crystal-mush zone. Melt–crystal equilibria and volatile contents in melt inclusions indicate temporary magma storage depths of < 8 km. Each of the magmas display quartz crystals containing melt inclusions that are compositionally highly evolved relative to the accompanying matrix glass, and thus point to a stage of more complete crystallisation. The matrix glass, enriched in Sr and Ti, represents a re-melting event of underlying the crystal pile induced by basaltic intrusion, presumably part of the same event that erupted scoria at the start of the eruption. This recharge rhyolite melt percolated upward and hybridised with the resident melts in each of the three magma pods. The Okareka episode rhyolites contrast with other well-documented rhyolites that are either continuously or discontinuously zoned, or have been homogenised during re-activation to a uniform composition. Rapid basalt dike intrusion to shallow levels appears to have (prematurely?) triggered the Okareka rhyolites into eruption, so that their early ponding in separate melt pods has been recorded before it could be masked by mixing or stratification had amalgamation into a larger body occurred.  相似文献   
128.
In epidemiology research, a list of residences a person has occupied as well as a history of tenants for a residence are useful pieces of information for investigating geographically localized risk factors, environmental exposures, and for analyzing disease clusters. This article reports on a methodology for constructing residential and tenure histories using multi‐year white page phone listings. Residential histories associate a person with a list of addresses of residence and the length of occupancy at each address. Tenure histories document the list of persons occupying a residence along with length of occupancy. These histories were created using fuzzy matching on name address pairs between sequential years. Simulated annual phone listing data were used to develop and test the methodology which was then applied to an actual white page phone listing for a study town in Maine. The approach is applied locally and generates partial local residential and tenure histories that capture local migrations. We see these local history sets as building blocks for constructing more geographically extensive histories over time. Geocoded results were compared against numbers of housing units reported in the 2000 and 2010 US Census to assess the proportion of local residences captured by phone listings.  相似文献   
129.
The impact of the 2004 Indian Ocean tsunami on coastal tourism communities highlights the vulnerability of tourism destinations to external shocks. Based on fieldwork conducted in Thailand in the wake of this disaster, this paper addresses one fundamental question: what sociopolitical and environmental conditions contributed to the vulnerability of the affected tourism community of Khao Lak in the southern Phang Nga Province. We argue that an understanding of the root causes of destination vulnerability is vital not only for the successful implementation of regional recovery plans, but also for building long‐term resilience against future shocks. In the absence of an appropriate tourism vulnerability framework, this paper analyzes Khao Lak's vulnerability through an innovative theoretical framework comprised of the sustainability vulnerability framework, relational scale and place. The findings reveal that Khao Lak's vulnerability is shaped by 13 interlinked factors. These are the complex outcomes of social norms and developmental and dynamic governance processes driven by the competing agendas and scaled actions of key government and industry stakeholders. The identification and understanding of the drivers of Khao Lak's vulnerability and a strong vulnerability framework have significant implications for the wider tourism community. First, the empirical findings provide tourism communities with a blueprint for understanding the foundations of their vulnerability to external shocks. Second, the tourism vulnerability framework presented here provides destination communities and government stakeholders with an analytical tool through which to analyze their unique sociopolitical conditions. Together, these empirical and theoretical contributions bring us closer to securing sustainable livelihood futures for tourism dependent communities.  相似文献   
130.
This paper provides an in-depth analysis of the links between dematerialisation and climate change mitigation. Methods used for material flow analyses (MFA) within the wider context of industrial ecology (which includes a focus on all resource flows in an economy, not purely material tonnage) tend to focus either on detoxification and pollution reduction or dematerialisation and resource productivity. An environmentally extended input–output (EEIO) model incorporates both aspects, which need to be dealt with when looking at how to meet challenging greenhouse gas (GHG) emission targets. The approach understands both production systems and consumption patterns and has the ability through scenarios to analyse the (GHG) effectiveness of a wide range of material efficiency options. This analysis adopts an environmentally extended input–output approach to assess the role of material efficiency measures in reducing UK GHG emissions by 2050. A method for projecting the variables and parameters in the model, including the supply of and demand for materials and products, is presented and applied to investigate thirteen material efficiency strategies in the UK.  相似文献   
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