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961.
Dhananjay A. Sant Sudesh K. Wadhawan Rajinder K. Ganjoo Nathani Basavaiah Prabhin Sukumaran Sourabh Bhattacharya 《Journal of the Geological Society of India》2011,78(2):147-156
The paraglacial sequence in the Leh valley, Ladakh Himalaya preserves imprints of various processes active during deglaciation
in the late phase of Last Glacial. In present work, a high resolution sedimentological record generated for Spituk is presented
identifying aeolian episodes, mudflow events from Ladakh Range and debris flows extending from Zanskar Range across present
Indus River. Two temporal phases of water ponding within Spituk Sequence are also identified. The seismites recorded at various
stratigraphic depths and their association with the sediment facies signifies gravity induced process besides possible seismic
activity as an added phenomena. Linkage between paraglacial processes since Last Glacial to Recent is tracked and evaluated. 相似文献
962.
D. Purushotham A. Narsing Rao M. Ravi Prakash Shakeel Ahmed G. Ashok Babu 《Journal of the Geological Society of India》2011,77(6):539-548
Maheshwaram watershed is situated in Ranga Reddy district of at a distance of about 30 km south of Hyderabad. The watershed
has an area of 53 km2 and has hard rock aquifers with semi-arid climate. The study area has been expanding at a fast pace and now has the distinction
of being one of the fastest growing urban centers, facing the problem of groundwater depletion and quality deterioration due
to the absence of perennial source of surface water and also due to over exploitation. Human activities involving industrial
and agricultural development and the inadequate management of land and water resources have, directly or indirectly resulted
in the degradation of environment viz. water and soil. 相似文献
963.
This paper assesses how far community led rural visions accord with the current thrust of rural planning policy delivery in
the UK. Adapting conventional visioning methods, qualitative techniques were used on eight different communities across urban,
exurban and rural Wales to elicit views relating to the kind of local countryside(s) that were desired. The results show that
the communities’ visions reflect an emerging consensus around local countryside priorities: multifunctionality, integration,
wider countryside protection, development based on need, and local distinctiveness according with the thrust of current planning
policy at national and local levels. However, there is a clear dichotomy between this and the reality of what communities
actually experienced in developments affecting their countryside. Here, universal criticism was encountered over the type,
pace and scale of development, the lack of rural specificity and the failure to take account of local community needs and
priorities. It is hypothesized that tensions between national and local politics and stakeholder power relations are playing
a crucial role in distorting the delivery of town and country planning. It is recommended that rural policy delivery must
become more “joined up” and rural proofed at national and local levels concomitant with a change in the operational culture
of agencies at the forefront of rural delivery. Essentially, effective engagement of top down approaches synergising with
bottom up community led ideas is long overdue. 相似文献
964.
Sigismond A. Wilson 《GeoJournal》2011,76(3):191-212
Although the Kimberley Process Certificate Scheme has considerably reduced the flow of conflict diamonds from 4% to less than
1%, other forms of illicit diamonds are estimated at 20% of global production. While scholars and policy makers have given
considerable attention to illicit mining and smuggling (with some success), illicit exploitation still hinders revenue generation
that is needed for economic growth and development in Sub-Saharan African (SSA) countries heavily reliant on alluvial minerals.
Based on surveys of 240 households in four diamondiferous chiefdoms in Kono District in Sierra Leone, key informant interviews,
focus groups and secondary data, and drawing from the actor-oriented approach and Le Billon (Fuelling war: natural resources
and armed conflict. London, International Institute for Strategic Studies, 2005) conceptualization of the political geography of the resource, this paper examines the problem of illicit diamond exploitation
in post-conflict Sierra Leone. It investigates: (1) the causes of illicit diamond mining and smuggling; (2) the spatial and
temporal aspects of illicit mining and smuggling, and (3) possible solutions to illicit diamond exploitation. The paper argues
that the ineffectiveness of national mining laws/policies has created conditions that are exploited by local and international
actors in the diamond industry. This is further exacerbated by the political geography of the resource. Study findings reveal
that while better mining regulation could reduce illicit exploitation, bringing buyers closers to miners and offering them
better prices for rough diamonds will minimize smuggling and thus increase government’s mineral revenue base. 相似文献
965.
The hydroxyl stretching frequencies of four phyllosilicates have been measured at high pressures and temperatures using an externally heated diamond-anvil cell and synchrotron infrared spectroscopy. Spectra were measured up to 26, 31, 21 and 8 GPa at room temperature for samples of talc, pyrophyllite, muscovite and 10-Å phase, respectively. Spectra were also measured in the range 273–500 K at ambient pressure for all samples and at 8–9 GPa for talc and pyrophyllite. The frequency of the Mg3OH band in talc increases with pressure due to the absence of hydrogen bonding. The different orientation of the hydroxyl group in pyrophyllite and muscovite leads to hydrogen bonding and a decrease in the frequency of the Al2OH band with pressure. 10-Å phase is approximately equivalent to talc with the addition of interlayer H2O. In a spectrum of a sample synthesised for 143 h, two hydroxyl stretching bands are clearly resolved on compression. One is the same as the Mg3OH band in talc, indicating the presence of intra-layer hydroxyl in a talc-like environment with no hydrogen bonding. The other, which separates from the talc-like band at 1 GPa, is associated with intra-layer hydroxyl that is hydrogen bonded to interlayer H2O. There are equivalent bands in high-pressure spectra of a sample of deuterated 10-Å phase, synthesised for 400 h. This sample shows a greater extent of hydrogen bonding at ambient pressure than the 143 h sample. For all of the phases studied, increasing temperature leads to a decrease in frequency for every hydroxyl stretching vibration, both at low and high pressures. The shifts in frequency with temperature are an order of magnitude greater than the shifts with pressure when normalised to previously measured structural parameters. 相似文献
966.
First- and second-order adaptation to natural hazards and extreme events in the context of climate change 总被引:2,自引:1,他引:2
Jörn Birkmann 《Natural Hazards》2011,58(2):811-840
This paper deals with coping and adaptation processes to natural hazards and (potential) climate change impacts. Selected
response measures to natural hazards are critically reviewed with respect to the actual and potential consequences that these
measures might imply for additional adaptation needs and changes within social-ecological systems. In this context, the author
introduces the concept of first- and second-order adaptation processes in order to underline the cascade process that adaptation
implies, the potentials for failure, and the limits of adaptation. Important aspects of first- and second-order adaptation
processes as well as the issue of the limits of adaptation are illustrated based on observations and empirical work conducted
in Vietnam. In its final part, the paper discusses the findings in light of selected theoretical approaches that might help
to understand how stabilization and destabilization processes are influenced or even triggered by adaptation measures. 相似文献
967.
Monometamorphic metasediments of Paleozoic or Mesozoic age constituting Schneeberg and Radenthein Complex experienced coherent deformation and metamorphism during Late Cretaceous times. Both complexes are part of the Eoalpine high-pressure wedge that formed an intracontinental suture and occur between the polymetamorphosed Ötztal–Bundschuh nappe system on top and the Texel–Millstatt Complex below. During Eoalpine orogeny Schneeberg and Radenthein Complexes were south-dipping and they experienced a common tectonometamorphic history from ca. 115 Ma onwards until unroofing of the Tauern Window in Miocene times. This evolution is subdivided into four distinct tectonometamorphic phases. Deformation stage D1 is characterized by WNW-directed shearing at high temperature conditions (550–600°C) and related to the initial exhumation of the high-pressure wedge. D2 and D3 are largely coaxial and evolved during high- to medium-temperature conditions (ca. 450 to ≥550°C). These stages are related to advanced exhumation and associated with large-scale folding of the high-pressure wedge including the Ötztal-Bundschuh nappe system above and the Texel–Millstatt Complex below. For the area west of the Tauern Window, F2/F3 fold interference results in the formation of large-scale sheath-folds in the frontal part of the nappe stack (formerly called “Schlingentektonik” by previous authors). Earlier thrusts were reactivated during Late Cretaceous normal faulting at the base of the Ötztal–Bundschuh nappe system and its cover. Deformation stage D4 is of Oligo-Miocene age and accounted for tilting of individual basement blocks along large-scale strike-slip shear zones. This tilting phase resulted from indentation of the Southern Alps accompanied by the formation of the Tauern Window. 相似文献
968.
Catarina Vinagre João Salgado Henrique N. Cabral Maria J. Costa 《Estuaries and Coasts》2011,34(4):663-674
River flow variability is known to influence estuarine production, yet knowledge on its effect upon estuarine food webs dynamics
is still scarce. Stable carbon and nitrogen isotopes were used to assess the effect of river flow in the connectivity and
food web interactions between the two main fish nursery areas of the Tagus estuary. The aims of the present work were to investigate
the seasonal variation in food web structure and the exchange rate of individuals of marine juvenile fish among estuarine
nurseries, to compare the spring of a rainy year (2001) with that of an average year (2000), and to investigate the impact
of the winter floods of 2001. A low level of connectivity was observed for the fish species that use these areas as nurseries.
In low river flow conditions, two isotopically distinct food webs were established in each nursery area. These food webs were
very sensitive to small variations in the freshwater input. Winter floods seem to disrupt the localized food webs that are
established in low river flow periods, leading to the re-establishment of a wider food web. While in rainy years this wide
food web is maintained until spring, in average years the food web undergoes fragmentation into two localized and isotopically
distinctive food webs. The increase in frequency of droughts due to climate change should lower the connectivity of the estuarine
fish nurseries food webs, causing habitat fragmentation and consequent loss in complexity and resilience. 相似文献
969.
We examined the anthropogenic and natural causes of flood risks in six representative cities in the Gangwon Province of Korea.
Flood damage per capita is mostly explained by cumulative upper 5% summer precipitation amount and the year. The increasing
flood damage is also associated with deforestation in upstream areas and intensive land use in lowlands. Human encroachment
on floodplains made these urban communities more vulnerable to floods. Without changes in the current flood management systems
of these cities, their vulnerability to flood risks will remain and may even increase under changing climate conditions. 相似文献
970.
A key concept in resilience studies is that human societies can learn from hazard events and use their accumulated social
memory to better contend with future catastrophes. This article explores the deliberate referral to historical records complied
after Hurricane Betsy in 1965 and how they were used to prepare for tropical storms at the time of Hurricane Katrina in 2005.
Despite proclamations that Louisiana would not repeat its mistakes, hazards planners seriously neglected the historical record. 相似文献