Mobility in marginalized spaces: Manoeuvring for survival among the Veddas in Sri Lanka     

Ragnhild Lund 《Norsk geografisk tidsskrift. Norwegian journal of geography》2013,67(4):200-209

In Sri Lanka the indigenous population, the Veddas, are rapidly losing their traditional habitats due to cash cropping and infrastructure development, and they are being forced to find new means of living. The purpose of the article is to show how mobility is an inherent characteristic of the new economy in the country and that mobility is gendered. The author documents how one group of Veddas has become immobilized (Dambane study village, which has turned into a tourist site) while another group has been forced to be more mobile (Henanigale study village, where emigration is increasingly practised) due to the same development policies. The study reveals that the market-led economy has caused spatial fixations that limit people more than they liberate them. These fixations take place in the domestic sphere as well as in the villages and they change gender relations, showing that mobility is intertwined with social processes that change local structures and relationships. In the case of the Veddas, living in marginalized places conditions their motility. Mobility is therefore a selective process and as much about the fact of moving as it is entangled with meaning and the power to produce (im)mobility at different scales.  相似文献   

Surface complexation modeling of Co(II) adsorption on mixtures of hydrous ferric oxide, quartz and kaolinite   总被引：1，自引：0，他引：1  

Christopher J. Landry  Tracy J. Lund  Soumya Das 《Geochimica et cosmochimica acta》2009,73(13):3723-7017

Co sorption was measured as a function of pH, ionic strength (0.001-0.1 M NaNO₃) and sorbate/sorbent ratio on pure quartz, HFO and kaolinite and on binary and ternary mixtures of the three solids. Sorption data measured for the pure solids were used to derive internally-consistent diffuse layer surface complexation model (DLM) stability constants for Co sorption. Co sorption on HFO could be adequately modeled over a broad range of ionic strengths and sorbate/sorbent ratios with a two variable-charge site model. Fits based on a single variable-charge site model were reasonable, but were improved by using ionic-strength dependent stability constants. A single variable-charge site model with an additional permanent ion exchange site produced the best fit to Co edges measured on kaolinite over a range of ionic strength and sorbate/sorbent ratios. These DLM fits were also improved by using ionic-strength dependent stability constants. The DLM approach could not adequately describe the slope of Co sorption edges on quartz. This study demonstrates that for accurate prediction of Co sorption over wide ranges of ionic strength and sorbate/sorbent ratio, the DLM may require ionic-strength dependent stability constants. DLM stability constants for Co sorption derived for the pure solids were used to predict sorption as a function of pH and solid concentration on binary and ternary mixtures of the three solids. Discrepancies between predictions and measurements were quantitatively similar to those observed for the pure mineral systems. Thus, a simple component additivity approach provides useful predictions of metal sorption in the mixed solid systems.  相似文献   

Gamma-burst positions - are they reliable?     

Niels Lund 《Astrophysics and Space Science》1995,231(1-2):217-226

Ever since the discovery of the Cosmic Gamma-Ray Bursts we have searched for the quiescent counterparts of these mysterious flashes. Without definite counterparts our pictures of the sources must remain vague. The review discusses a number of techniques which have been applied to the gamma burst localization problem and their limitations. The most accurate technique to-date is the Interplanetary Network (IPN) timing technique. Considering the lack of success in the searches for counterparts in even the smallest gamma burst error boxes, it seems, that the next generation of satellite gamma burst detectors must be designed to allow immediate follow-up with sensitive telescopes. Concepts to achieve this goal are discussed.  相似文献   

Response of North American Great Basin Lakes to Dansgaard–Oeschger oscillations     

Larry Benson  Steve Lund  Rob Negrini  Braddock Linsley  Mladen Zic 《Quaternary Science Reviews》2003,22(21-22):2239-2251

We correlate oscillations in the hydrologic and/or cryologic balances of four Great Basin surface-water systems with Dansgaard–Oeschger (D–O) events 2–12. This correlation is relatively strong at the location of the magnetic signature used to link the lake records, but becomes less well constrained with distance/time from the signature. Comparison of proxy glacial and hydrologic records from Owens and Pyramid lakes indicates that Sierran glacial advances occurred during times of relative dryness. If our hypothesized correlation between the lake-based records and the GISP2 δ¹⁸O record is correct, it suggests that North Atlantic D–O stades were associated with relatively cold and dry conditions and that interstades were associated with relatively warm and wet conditions throughout the Great Basin between 50,500 and 27,000 GISP2 yr B.P. The Great Basin lacustrine climate records reinforce the hypothesis that D–O events affected the climate throughout much of the Northern Hemisphere during marine isotope stages 2 and 3. However, the absolute phasing between lake-size and ice-core δ¹⁸O records remains difficult to determine.  相似文献   

Explosion-Generated Short-Period Surface Wave Dispersion and Noise Studies Along Linear Seismic Arrays In Southern Sweden   总被引：1，自引：0，他引：1  

Kjell Arström  Carl-Erik Lund 《Geophysical Journal International》1993,114(1):103-115

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Insolation forcing of Holocene climate change in Southern California: a sediment study from Lake Elsinore     

Matthew E. Kirby  Steve P. Lund  Michael A. Anderson  Broxton W. Bird 《Journal of Paleolimnology》2007,38(3):395-417

Lake Elsinore is the largest natural lake in Southern California. As such, the lake provides a unique opportunity to investigate terrestrial climate on timescales otherwise underrepresented in the region’s terrestrial environment. In November 2003, three ∼10 m drill cores were extracted from the depocenter region of Lake Elsinore. These drill cores, spanning the past 9,500–11,200 calendar years, represent the first complete Holocene record of terrestrial climate from Southern California. In this paper, we focus on two adjacent, depocenter cores (LEGC03-2 and LEGC03-3), which have been correlated to develop a single composite core. Twenty-two AMS ¹⁴C dates on bulk organic matter and one cross-correlated exotic pollen age constitute the composite core’s age control. Several methods of analysis, including mass magnetic susceptibility, % total organic matter, % total carbonate, % HCl-extractable Al, and total inorganic P are used to infer climate for the past 9,500 calendar years in Southern California. Together, these data indicate a wet early Holocene followed by a long-term drying trend. Recent lake-level reconstructions from Owens Lake and Tulare Lake support our contention for a wetter-than-today early Holocene. Lacustrine sediments from the Mojave Desert also support our conclusions. We suggest that over the duration of the Holocene changing summer/winter insolation alters the region’s long-term hydrologic balance through its modulation of atmospheric circulation and its associated storm tracks. Minimum early Holocene winter insolation and maximum summer insolation act together to increase the region’s total annual precipitation by increasing the frequency of winter storms as well as enhancing the magnitude and spatial extent of the North American monsoon, the frequency of land-falling tropical cyclones in Southern California, and regional convective storms, respectively. Gradual decreases in summer insolation and increases in winter insolation produce the opposite effect with maximum drying in the late Holocene.  相似文献   

Hydro-economic analysis of groundwater pumping for irrigated agriculture in California’s Central Valley,USA     

Josué Medellín-Azuara  Duncan MacEwan  Richard E. Howitt  George Koruakos  Emin C. Dogrul  Charles F. Brush  Tariq N. Kadir  Thomas Harter  Forrest Melton  Jay R. Lund 《Hydrogeology Journal》2015,23(6):1205-1216

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Hydro-economic models: Concepts, design, applications, and future prospects   总被引：6，自引：0，他引：6  

Julien J. Harou  Manuel Pulido-Velazquez  David E. Rosenberg  Josu Medellín-Azuara  Jay R. Lund  Richard E. Howitt 《Journal of Hydrology》2009,375(3-4):627-643

Future water management will shift from building new water supply systems to better operating existing ones. The variation of water values in time and space will increasingly motivate efforts to address water scarcity and reduce water conflicts. Hydro-economic models represent spatially distributed water resource systems, infrastructure, management options and economic values in an integrated manner. In these tools water allocations and management are either driven by the economic value of water or economically evaluated to provide policy insights and reveal opportunities for better management. A central concept is that water demands are not fixed requirements but rather functions where quantities of water use at different times have varying total and marginal economic values. This paper reviews techniques to characterize the economic value of water use and include such values in mathematical models. We identify the key steps in model design and diverse problems, formulations, levels of integration, spatial and temporal scales, and solution techniques addressed and used by over 80 hydro-economic modeling efforts dating back 45-years from 23 countries. We list current limitations of the approach, suggest directions for future work, and recommend ways to improve policy relevance.  相似文献   

Adapting California’s water management to climate change   总被引：1，自引：0，他引：1  

Ellen Hanak  Jay R. Lund 《Climatic change》2012,111(1):17-44

California faces significant water management challenges from climate change, affecting water supply, aquatic ecosystems, and flood risks. Fortunately, the state also possesses adaptation tools and institutional capabilities that can limit vulnerability to changing conditions. Water supply managers have begun using underground storage, water transfers, conservation, recycling, and desalination to meet changing demands. These same tools are promising options for responding to a wide range of climate changes. Likewise, many staples of flood management—including reservoir operations, levees, bypasses, insurance, and land-use regulation—are available for the challenges of increased floods. Yet actions are also needed to improve response capacity. For water supply, a central issue is the management of the Sacramento-San Joaquin Delta, where new conveyance, habitat investments, and regulations are needed to sustain water supplies and protect endangered fish species. For flood management, among the least-examined aspects of water management with climate change, needed reforms include forward-looking reservoir operation planning and floodplain mapping, less restrictive rules for raising local funds, and improved public information on flood risks. For water quality, an urgent priority is better science. Although local agencies are central players, adaptation will require strong-willed state leadership to shape institutions, incentives, and regulations capable of responding to change. Federal cooperation often will be essential.  相似文献   

A Monte-Carlo game theoretic approach for Multi-Criteria Decision Making under uncertainty   总被引：2，自引：0，他引：2  

Kaveh Madani  Jay R. Lund 《Advances in water resources》2011,34(5):607-616

Game theory provides a useful framework for studying Multi-Criteria Decision Making problems. This paper suggests modeling Multi-Criteria Decision Making problems as strategic games and solving them using non-cooperative game theory concepts. The suggested method can be used to prescribe non-dominated solutions and also can be used as a method to predict the outcome of a decision making problem. Non-cooperative stability definitions for solving the games allow consideration of non-cooperative behaviors, often neglected by other methods which assume perfect cooperation among decision makers. To deal with the uncertainty in input variables a Monte-Carlo Game Theory (MCGT) approach is suggested which maps the stochastic problem into many deterministic strategic games. The games are solved using non-cooperative stability definitions and the results include possible effects of uncertainty in input variables on outcomes. The method can handle multi-criteria multi-decision-maker problems with uncertainty. The suggested method does not require criteria weighting, developing a compound decision objective, and accurate quantitative (cardinal) information as it simplifies the decision analysis by solving problems based on qualitative (ordinal) information, reducing the computational burden substantially. The MCGT method is applied to analyze California’s Sacramento-San Joaquin Delta problem. The suggested method provides insights, identifies non-dominated alternatives, and predicts likely decision outcomes.  相似文献