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21.
Nature-triggered hazards and disasters have traditionally been treated only from the lens of geophysical and biophysical processes,
implying that the root cause of large-scale death and destruction lies in the natural domain rather than in a coupled human–environment
system. Conceptually, the physical domain has been seen as discrete and separate from human entities, and solutions were sought
in the technological intervention and control of the physical environment—solutions that often ended up being less effective
than hoped for and sometimes even counter productive. At all levels, institutions have directed and redirected most of their
financial and logistical resources into the search for scientific and engineering solutions without allocating due attention
and resources towards the assessment of effects and effectiveness of the applications of such technological outcomes. However,
over the last two decades, forceful criticisms of the ‘dominant’ technocratic approach to hazards analysis have appeared in
the literature and consequently there has not only been a shift in thinking of causation of disaster loss in terms of human
vulnerability, but also newer questions have arisen regarding distinguishing between the ‘physical exposure’ of people to
threats and societal vulnerability, and linking them with propensity to hazards loss.
Though the vulnerability/resilience paradigm has largely replaced the hazards paradigm within the social sciences and much
of the professional emergency and disaster management communities, this shift of thinking has not progressed to much of the
physical science community, decision-makers and the public, who have not yet accepted the idea that understanding and using
human and societal dimensions is equally or more important than trying to deal and control nature through the use of technology.
This special issue is intended to further the idea that the aspects of community and peoples’ power to mitigate, to improve
coping mechanisms, to respond effectively, and recover with vigor against the environmental extremes are of paramount conceptual
and policy importance. 相似文献
22.
A simple, well-constrained simulation of solute increases in a downgradient direction was used in the shallow unconfined aquifer
of eastern Abu Dhabi Emirate (United Arab Emirates). The simulation indicates that the observed exponential increase in solute
concentrations results from a combination of upward transport of solutes from underlying mudstones and evaporites, and groundwater
losses by evaporation. Groundwater recharge and discharge flux in unconfined regional aquifers in arid regions commonly are
difficult to estimate because there are few constraints on the flux of water lost or gained from the system. Total dissolved
solids (TDS) and deuterium isotopes (δ2H) in groundwater are used to constrain estimated fluxes to the shallow aquifer of eastern Abu Dhabi Emirate. Vertical upward
transport of solutes from underlying mudstones and evaporites accounts for solute increases along approximately the first
80 km of the simulated flow path, but a combination of upward solute transport and evaporation is necessary to explain observed
solute concentrations beyond 80 km. Mobilization and transport of solutes in the unsaturated zone by recharging precipitation
is not a significant factor.
Résumé Une simulation simple et bien contrainte de l’augmentation des solutés dans la direction de l’écoulement a été réalisée sur l’aquifère phréatique et libre de l’Est de l’émirat d’Abu Dhabi (émirats Arabes Unis). La simulation indique que l’augmentation observée de solutés, de forme exponentielle, est le produit de la combinaison du transport ascendant de solutés provenant des mudstones et des évaporites sous-jacents, et de l’évaporation des eaux souterraines. La recharge des eaux souterraines et les flux de vidange dans les aquifères régionaux libres des régions arides sont habituellement difficiles à estimer du fait du peu de contraintes agissant sur la perte ou le gain d’eau dans le système. La charge dissoute totale (TDS, en anglais) et les isotopes deutérium (δ2H) des eaux souterraines sont utilisés pour contraindre l’estimation des flux en direction de l’aquifère phréatique de l’Est de l’émirat d’Abu Dhabi. Le transport vertical ascendant des solutés à partir des mudstones et des évaporites fait parti des processus qui concentrent les solutés approximativement le long des 80 premiers kilomètres du trajet des écoulements simulés, mais une combinaison du transport ascendant des solutés et de l’évaporation est nécessaire pour expliquer les concentrations observées en soluté au delà des 80 km. La mobilisation et le transport des solutés par les précipitations efficaces dans la zone non saturée ne représentent pas des facteurs significatifs.
Resumen Se utilizó una simulación simple y muy restringida, de incrementos de soluto en la dirección del flujo, en el acuífero libre poco profundo del Emirato oriental de Abu Dhabi, (Emiratos árabes Unidos). La simulación indica que el aumento exponencial observado en las concentraciones del soluto, resulta de una combinación de transporte ascendente de solutos desde las evaporitas y lodolitas subyacentes, y por pérdidas del agua subterránea por evaporación. Los flujos de recarga y descarga de agua subterránea, en los acuíferos libres regionales en regiones áridas, normalmente son difíciles estimar, porque hay algunas restricciones en el flujo de agua perdido o ganado por el sistema. Los sólidos disueltos totales (TDS) y los isótopos de deuterio (δ2H) en el agua subterránea, se usan para forzar los flujos estimados hacia el acuífero poco profundo del Emirato oriental de Abu Dhabi. El transporte ascendente vertical de solutos desde las lodolitas y evaporitas subyacentes, involucra los aumentos del soluto a lo largo de aproximadamente los primeros 80 Km. de la dirección de flujo simulada, pero es necesaria una combinación de transporte ascendente del soluto y la evaporación para explicar las concentraciones del soluto observadas más allá de 80 Km. La movilización y transporte de solutos en la zona no saturada, por recarga debida a precipitación, no es un factor significante.相似文献
23.
24.
Mohamed M. Abu-Zeid Ashraf R. Baghdady Hassan A. El-Etr 《Journal of Arid Environments》2001,48(4):475
Sand dunes and interdune sediments around Al Ain city have markedly high carbonate contents which increase towards Jabal Hafit mountain and the Arabian Gulf coast. The dunes are composed predominantly of well-sorted fine sands, consisting of unstrained quartz and carbonate grains together with minor proportions of chert and feldspars. Scanning electron microscope (SEM) examination reveals that quartz grains display various mechanically- and chemically-formed surface textures. The heavy minerals are dominated by opaques and pyroxenes with minor tourmaline, garnet, rutile, epidote, monazite, zircon, hornblende and staurolite.Interdune sediments consist of fine and very fine, poorly- to extremely poorly-sorted sands together with small concentrations of gravel, silt and clay. The light sand fractions compositionally resemble those of dunes but contain, in addition, gypsum, anhydrite, halite and celestite. Percentages of pyroxenes are higher whereas those of zircon, tourmaline and rutile are lower than in dunes. X-ray diffractometry reveals that the clay fractions consist solely of palygorskite. Generally, interdune sediments are much less mature texturally and mineralogically than dune sands; the maturity of both types of sediments decreases toward the NE of the study area.Sand dunes in the various districts of the greater Al Ain area are genetically related. Also, there is a partial genetic relationship between the dunes and interdune sediments; both are mainly multicyclic. Their major parts were brought mainly by the dominant north-west (El Shamal) winds from older dune fields in other localities in U.A.E., Qatar and El-Rub El-Khali. Local contributions to the dune fields from Jabal Hafit mountain, the Oman Mountains and the calcareous coast of the Arabian Gulf were, in cases, significant. Also, authigenesis by groundwater under highly evaporitic conditions played a major role in the formation of interdune sediments through the genesis of the clay and some nonclay minerals. 相似文献
25.
Colin R. Ward John C. Taylor C. E. Matulis L. S. Dale 《International Journal of Coal Geology》2001,46(2-4)
The mineral matter in the eight reference North American coal samples of the Argonne Premium Coal series has been investigated on a quantitative basis using X-ray diffraction (XRD) techniques. X-ray diffraction data obtained from electronic low-temperature (oxygen–plasma) ash (LTA) residues, from ashes produced by heating the coals in air at 370°C, and also from the raw coals themselves, were evaluated using an interactive data processing system (
™) based on Rietveld interpretation methods. The results from the three types of material (LTA, 370°C ash and raw coal) were compared for each sample. This allowed the components present in the raw coals in crystalline form to be recognised separately from mineral artifacts produced, particularly in the low-rank coals, from interaction of organically associated elements (Ca, S, etc.) during the two ashing processes.After the allowance for the production of any artifacts, the quantitative mineral assemblages identified from XRD of the raw coals were found to be consistent, even for coals having a relatively low ash percentage (around 5%), with the results obtained from the respective mineral concentrates prepared by the ashing methods. The effects of heating the coal to 370°C could also be distinguished, relative to the raw coal or the LTA, through changes in components such as pyrite and the clay minerals.Although some areas of uncertainty exist, particularly with magnesium in the low-rank coals, the calculated chemical compositions of the coal ash derived from the mineral mixtures identified for each coal were also found to be consistent with the results of direct chemical analysis of the respective coal ash materials. 相似文献
26.
Stephen?MoyseyEmail author Stanley?N.?Davis Marek?Zreda L.?DeWayne?Cecil 《Hydrogeology Journal》2003,11(6):615-627
The natural distribution of 36Cl/Cl in groundwater across the continental United States has recently been reported by Davis et al. (2003). In this paper, the large-scale processes and atmospheric sources of 36Cl and chloride responsible for controlling the observed 36Cl/Cl distribution are discussed.The dominant process that affects 36Cl/Cl in meteoric groundwater at the continental scale is the fallout of stable chloride from the atmosphere, which is mainly derived from oceanic sources. Atmospheric circulation transports marine chloride to the continental interior, where distance from the coast, topography, and wind patterns define the chloride distribution. The only major deviation from this pattern is observed in northern Utah and southern Idaho where it is inferred that a continental source of chloride exists in the Bonneville Salt Flats, Utah.In contrast to previous studies, the atmospheric flux of 36Cl to the land surface was found to be approximately constant over the United States, without a strong correlation between local 36Cl fallout and annual precipitation. However, the correlation between these variables was significantly improved (R
2=0.15 to R
2=0.55) when data from the southeastern USA, which presumably have lower than average atmospheric 36Cl concentrations, were excluded. The total mean flux of 36Cl over the continental United States and total global mean flux of 36Cl are calculated to be 30.5±7.0 and 19.6±4.5 atoms m–2 s–1, respectively.The 36Cl/Cl distribution calculated by Bentley et al. (1986) underestimates the magnitude and variability observed for the measured 36Cl/Cl distribution across the continental United States. The model proposed by Hainsworth (1994) provides the best overall fit to the observed 36Cl/Cl distribution in this study. A process-oriented model by Phillips (2000) generally overestimates 36Cl/Cl in most parts of the country and has several significant local departures from the empirical data.
Resumen Davis et al. (2003) han informado de la distribución natural de la proporción 36Cl/Cl en las aguas subterráneas de la parte continental de los Estados Unidos de América [EUA]. En este artículo, se discute cuáles son los procesos a gran escala y las fuentes atmosféricas del 36Cl y del cloruro que dan lugar a la distribución observada de 36Cl/Cl.El proceso dominante que afecta a la relación 36Cl/Cl en las aguas subterráneas de origen meteórico a escala continental es el aporte de cloruro estable desde la atmósfera, que procede principalmente de los océanos. La circulación atmosférica transporta el cloruro marino hacia el interior, donde la distancia a la costa, topografía y corrientes del viento definen la distribución del cloruro. La única desviación principal de este esquema tiene lugar al norte de Utah y en el sur de Idaho, donde se deduce que existe una fuente continental de cloruro en los Rellanos Salados de Bonneville (Salt Flats).En contraste con estudios previos (Knies et al. 1994; Phillips 2000), se ha descubierto que el flujo atmosférico de 36Cl hacia la superficie terrestre es aproximadamente constante en todos los estados, sin deducirse una correlación fuerte entre el aporte de 36Cl y la precipitación anual. Sin embargo, la correlación entre estas variables se ve mejorada de forma significativa, con coeficientes de regresión comprendidos entre 0,15 y 0,55, cuando se excluyen los datos recogidos en el sudeste de los EUA, que tienen concentraciones de 36Cl atmosférico presuntamente inferiores a la media. El flujo medio total de 36Cl calculado en la zona continental de los Estados Unidos vale 30,5±7,0 átomos por metro cuadrado y segundo, mientras que el flujo total global de 36Cl es de 19,6±4,5 átomos por metro cuadrado y segundo.La distribución de 36Cl/Cl calculada por Bentley et al. (1986) infravalora la magnitud y variabilidad observada en los valores medidos a lo largo de los Estados Unidos. El modelo propuesto por Hainsworth (1994) proporciona el mejor ajuste conjunto a la distribución observada de 36Cl/Cl en este estudio. El modelo orientado a procesos de Phillips (2000) sobreestima por lo general la distribución de 36Cl/Cl en la mayoría del país y difiere significativamente de algunos valores locales empíricos.
Résumé La distribution naturelle du rapport 36Cl/Cl dans les eaux souterraines des États-Unis a été récemment présentée par Davis et al. (2003). Dans ce travail, les processus à grande échelle et les sources atmosphériques de 36Cl et de chlorure responsables du contrôle de la distribution observée du rapport 36Cl/Cl sont discutés. Le processus dominant qui affecte le rapport 36Cl/Cl dans les eaux souterraines dorigine météorique à léchelle continentale est lapport atmosphérique de chlorure stable, qui provient pour lessentiel de sources océaniques. La circulation atmosphérique transporte des chlorures marins vers lintérieur des continents, où la distribution de chlorure est définie par la distance à la côte, la topographie et les régimes des vents. La seule exception majeure à ce schéma est observée dans le nord de lUtah et le sud de lIdaho où lon suppose quil existe une source continentale de chlorure dans les bas-fonds salés de Bonneville. Au contraire de précédentes études (Knies et al. 1994; Phillips 2000), on trouve que le flux atmosphérique de 36Cl vers le sol est approximativement constant sur lensemble des États-Unis, sans forte corrélation entre la retombée locale de 36Cl et les précipitations annuelles. Cependant, la corrélation entre ces variables devient significative (R 2=0.15 à 0.55) lorsquon supprime les données du sud-est des États-Unis, dont on pense quelles présentent des concentrations en 36Cl atmosphérique inférieures à la moyenne. Le flux total moyen de 36Cl sur les États-Unis continentaux et le flux moyen global de 36Cl sont respectivement évalués à 30.5 ± 7.0 et 19.6 ± 4.5 atomes.m–2.s–1. La distribution du rapport 36Cl/Cl calculée par Bentley et al. (1986) sous-estime lordre de grandeur et la variabilité observés pour la distribution mesurée du rapport 36Cl/Cl sur les États-Unis continentaux. Le modèle proposé par Hainsworth (1994) fournit le meilleur ajustement densemble à la distribution du rapport 36Cl/Cl observée dans cette étude. Un modèle orienté vers les processus proposé par Phillips (2000) surestime dans lensemble le rapport 36Cl/Cl dans la plupart des régions du pays et présente plusieurs désaccords locaux avec les données empiriques.相似文献
27.
重点介绍了当前欧美资助海洋科学研究的基本情况、优先资助领域和重要研究计划等,对欧美当前海洋科学研究的基本特点做了简要分析;并提出了我国下世纪初的海洋科学研究优先发展领域。 相似文献
28.
Service contracts have emerged as an important instrument to secure a long-term relationship between carriers in the container shipping industry and shippers requiring scheduled services covering a global market. This contract, entered into largely on an individual and confidential basis, continues to enjoy anti-trust immunity under current United States and European Union regulations. It will continue to be in place even after the EC Council Regulation 4056/86 is repealed in October 2008 although it may operate in a modified way because of the absence of the common external conference tariff. This article examines the implications of this instrument on the international supply chain and explores its future role in defining efficiencies in international trade flows. 相似文献
29.
This article analyzes the recent growth and configuration of Fair Trade networks connecting South African Rooibos tea producers with American consumer markets. As we demonstrate, Fair Trade’s growth in the Rooibos sector engages key issues of black empowerment, land reform, and sustainable development in post-Apartheid South Africa. Fair Trade networks provide small-scale black Rooibos producers with critical markets. Most significantly, the Wupperthal and Heiveld cooperatives have upgraded into processing and packaging and their jointly owned Fairpackers facility now exports shelf-ready Rooibos tea. Analyzing the nature of US Fair Trade Rooibos buyers and their South African sourcing arrangements, we identify key variations in Fair Trade commitment and engagement between mission-driven and market-driven distributors. While mission-driven buyers engage small-scale Rooibos cooperatives in multifaceted partnership networks, market-driven buyers pursue conventional sourcing strategies favoring purchases from large plantations and exporters. We conclude that tensions between a radical and commercial orientation toward Fair Trade in Rooibos tea networks in many ways mirror those in the broader movement. 相似文献
30.
In irrigated agricultural landscapes, land-use conversion may have landscape-level social, hydrological, and ecological effects. We used geographic information systems (GIS) and interviews to analyze development effects on irrigation in the Henry's Fork Watershed, Idaho. Farmers developed irrigation there in the 19th century, and incidental recharge from canal seepage and flood irrigation raised groundwater levels and expanded wetlands. Cohesive culture in agricultural communities sustained irrigation systems until amenity-driven demographic shifts beginning in the 1970s led to development approved by local governments with land-use planning but no water-management authority. Although only 5% of irrigated land has been converted, development has fragmented irrigated landscapes and made canal-system operation more difficult, potentially reducing groundwater levels, wetland extent, and return flows critical to downstream irrigators and fish and wildlife. We discuss future scenarios, highlighting the need for increased communication among local and state governments regarding land use and water management in irrigated landscapes across the West. 相似文献