Spatial decision support systems. Principles and practices,by Ramathan Sugumaran and John DeGroote,CRC Press, 2012, 507 pp., $129.95, £80.99, €101.99 (hardcover), ISBN-10: 1420062093, ISBN-13: 978-1420062090     

Laurence Jones 《International journal of geographical information science》2013,27(5):1045-1047

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Party politics,the poor and the city: Reflections from the South African case     

Claire Bénit-Gbaffou  Laurence Piper 《Geoforum》2012,43(2):173-177

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Upwelling age: an indicator of local tendency for coastal upwelling     

Lide Jiang  Laurence C. Breaker  Xiao-Hai Yan 《Journal of Oceanography》2012,68(2):337-344

A proxy named “upwelling age”, defined as the ratio of wind time scale to “advection time”, was developed to quantify the local tendency for coastal upwelling. The formulation of the “advection time” was derived from Ekman theory. A 3D numerical model was used to validate and refine the theoretical formula by simulating a total of 30 cases of different bottom topographies and wind stresses. The results agree reasonably well with the theoretical formulation although some modifications are necessary. The final formulation of the “advection time” was parameterized as a function of pycnocline depth, bottom slope, and wind stress.  相似文献   

Paleolimnological evidence of mining and demographic impacts on Lac Dauriat, Schefferville (subarctic Québec, Canada)     

Laurence Laperrière  Marie-Andrée Fallu  Sonja Hausmann  Reinhard Pienitz  Derek Muir 《Journal of Paleolimnology》2008,40(1):309-324

Qualitative and quantitative analysis of fossil diatoms and geochemical signals preserved in the sediments of Lac Dauriat (subarctic Quebec) were performed to evaluate the impacts of nearby mining activity and the expansion of the town of Schefferville on the water quality of the lake, and to reconstruct the changes of its trophic status. The presence of taxa typical of nutrient-enriched environments (e.g., Cyclostephanos invisitatus, Nitzschia gracilis, Nitzschia perminuta) and the low percentages of chrysophytes were indicative of the advanced state of eutrophication of the lake during the peak of mining activity, and were evidence of the negative impacts of municipal waste on the water quality of Lac Dauriat. Sedimentary analysis of metals, notably lead, mercury, cadmium, bismuth, cobalt, copper and zinc, showed maximum concentrations between 1940 and 1960 with mining era to pre-development enrichment factors ranging from 4.5 to 7.9. The changes seen in recent sediments reflected 3 distinct stages in the recent history of this ecosystem: (a) the non-perturbed, pre-mining (1882–1939), (b) the perturbed, mining period (1939–1977) with accelerated eutrophication, and (c) the post-mining period (1977–1999) with indications of natural recovery of the system after the installation of a water treatment plant in 1975, the closing of the mine in 1983, and the subsequent exodus of the town’s population. Despite the trajectory towards a return to the lake’s natural conditions, water resource managers and (paleo-)limnologists should be alarmed that the impacts of past human disturbance are still in evidence more than 20 years after the closure of the mines, and that Lac Dauriat has yet to reach its natural state of the period preceding extreme anthropogenic impact.  相似文献   

RICE PRODUCER‐PROCESSOR NETWORKS IN CÔTE D'IVOIRE*     

Laurence Becker  N'guessan Yoboué 《Geographical review》2009,99(2):164-185

ABSTRACT. Pressured by structural adjustment loan conditions, Côte d'Ivoire reduced state support for rice production and processing during the 1990s. In this article we examine how various actors in the rice commodity chain adapted to the macroeconomic reforms. Following a brief history of the rice sector, we present the results of fieldwork based on interviews conducted in 2002 of farmers, millers, traders, and workers in the state extension service and nongovernmental organizations. We found that, in the absence of state supports for farmers, private millers became the focal point of regional producer‐processor rice networks. The four networks identified became the sole source of domestic commercial rice when the state removed subsidies for fertilizer and modern seeds, privatized extension, and liberalized prices and imports. To increase their role in the national rice supply, the rice networks may need support through microlending and a focus on niche markets.  相似文献   

Future heat vulnerability in California, Part II: projecting future heat-related mortality   总被引：1，自引：0，他引：1  

Scott C. Sheridan  Michael J. Allen  Cameron C. Lee  Laurence S. Kalkstein 《Climatic change》2012,115(2):311-326

Through the 21^st century, a significant increase in heat events is likely across California (USA). Beyond any climate change, the state will become more vulnerable through demographic changes resulting in a rapidly aging population. To assess these impacts, future heat-related mortality estimates are derived for nine metropolitan areas in the state for the remainder of the century. Heat-related mortality is first assessed by initially determining historical weather-type mortality relationships for each metropolitan area. These are then projected into the future based on predicted weather types created in Part I. Estimates account for several levels of uncertainty: for each metropolitan area, mortality values are produced for five different climate model-scenarios, three different population projections (along with a constant-population model), and with and without partial acclimatization. Major urban centers could have a greater than tenfold increase in short-term increases in heat-related mortality in the over 65 age group by the 2090s.  相似文献   

Corrigendum to “A closer look at regime shifts based on coastal observations along the eastern boundary of the North Pacific” [Continental Shelf Research 27 (2007) 2250–2277]     

Laurence C. Breaker 《Continental Shelf Research》2008

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Application of geochemical and stable isotopic tracers to investigate groundwater salinity in the Ochi-Narkwa Basin,Ghana   总被引：1，自引：1，他引：0  

Samuel Y. Ganyaglo  Shiloh Osae  Tetteh Akiti  Thomas Armah  Laurence Gourcy  Tomas Vitvar 《水文科学杂志》2017,62(8):1301-1316

Rainwater, groundwater and soil-water samples were analysed to assess groundwater geochemistry and the origin of salinity in the Ochi-Narkwa basin of the Central Region of Ghana. The samples were measured for major ions and stable isotopes (δ¹⁸O, δ²H and δ¹³C). The Cl^? content in rainwater decreased with distance from the coast. The major hydrochemical facies were Na-Cl for the shallow groundwaters and Ca-Mg-HCO₃, Na-Cl and Ca-Mg-Cl-SO₄ for the deep groundwaters. Groundwater salinization is caused largely by halite dissolution and to a minor extent by silicate weathering and seawater intrusion. Stable isotope composition of the groundwaters followed a slope of 3.44, suggesting a mixing line. Chloride profiles in the soil zone revealed the existence of salt crusts, which support halite dissolution in the study area. A conceptual flow model developed to explain the mechanism of salinization showed principal groundwater flow in the NW–SE direction.