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Selected AbstractsDepositional history and evolution of the Paso del Indio site, Vega Baja, Puerto RicoGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 6 2003Jeffrey J. Clark Potshards discovered during excavation of bridge pilasters for a major expressway over the Rio Indio floodplain, a stream incised within the karsts of north-central Puerto Rico, required large-scale archaeological excavation. Five-meter-deep bridge pilaster excavations in the alluvial valley provide a 4500-year history of deposition. Stratigraphic analysis of the exposed pilaster walls in combination with textural and organic carbon analyses of sediment cores obtained over a much broader area suggest a fluvial system dominated by overbank deposition. Six sequences of alternating light and dark layers of sediment were identified. The darker layers are largely composed of silts and clays, whereas the lighter layers are rich in sand-sized sediment. Archaeological evidence indicates the organic-rich dark layers, believed to be buried A horizons, coincide with pre-historic occupation by Cedrosan Saladoid, Elenan Ostionoid, and Chican Ostionoid, extending from A.D. 450 to A.D. 1500. Lighter layers below the dark soil horizons are interpreted as overbank deposits from large magnitude flood events. The floodplain aggraded discontinuously with rapid deposition of sand followed by gradual accumulation of silt, clay, and organic material. An approximately 1-m-thick layer of coarse sand and gravel halfway up the stratigraphic column represents an episode of more frequent and severe floods. Based on radiocarbon ages, this layer aggraded between A.D. 1000 and A.D. 1100, which is well within the Elenan Ostionoid era (A.D. 900,1200). Rates of sedimentation during this period were approximately 8 mm per year, ten times greater than the estimates of sedimentation rates before and after this flood sequence. The cause for the change in deposition is unknown. Nonetheless the Elenan Ostionoid would have had to endure frequent loss of habitation structures and crops during these events. © 2003 Wiley Periodicals, Inc. [source] The possible hydrologic effects of the proposed lignite open-cast mining in Drama lignite field, GreeceHYDROLOGICAL PROCESSES, Issue 11 2008Sotiris Panilas Abstract The present study investigates the possible hydrologic effects of the proposed lignite open-cast mining in Drama lignite field (north Greece). Recent years have seen a rapid increase in surface mining. This activity has generated a growing concern for the potential environmental impacts associated with large scale surface mining. In order to achieve a safe mine operation and allow extraction of lignite to considerable depths, extensive dewatering by pumping will be necessary, while at the same time it is desirable to avoid presence of overpumping conditions in the broader area. Based on stratigrafic, hydrologic and hydrogeologic data, a three-dimensional finite difference model was developed in order to simulate the dewatering process of the western part of the lignite open-cast mine in Drama and to predict both spatially and temporally the decline of ground water level down to the lignite surface. The dewatering of the part of the aquifer which underlies the mine area will influence the hydrological conditions of the broader region. The most important anticipated effects will be the abandonment of shallow wells as well as the decrease of ground water pumping rates of deep wells. Aquifer discharge towards the ditches of the study area will cease and there will be an inversion of ground water flow from the ditches towards the underlying aquifer. Dewatering activities will probably result in minor subsidence of the nearby peat deposits of Drama Philippi marshes. Moreover, sand pumping as well as the presence of gasses is likely to cause local subsidence phenomena, mainly in the pit slopes. Copyright © 2007 John Wiley & Sons, Ltd. [source] Low-grade dysplasia component in early invasive squamous cell carcinoma of the esophagusJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2010Yuichi Shimizu Abstract Background and Aims:, It has not been determined whether low-grade squamous dysplasia (LGD) of the esophagus is a precancerous lesion or not. If LGD progresses to squamous cell carcinoma, early carcinoma lesions that have such a natural history might contain a remaining LGD component. Methods:, The lesions in the 68 patients with early invasive squamous cell carcinoma who underwent endoscopic mucosal resection were examined for the presence of an LGD component. If LGD components were observed, the degrees of architectural and cytological abnormalities of LGD components and those of tumor invasive fronts in the same lesions were studied. The degrees of abnormalities of 28 small LGD lesions were also studied. Results:, Histological examination of resected specimens confirmed LGD components in 43% of the squamous cell carcinoma lesions. The lesions of lamina propria mucosae (m2) cancer contained a significantly broader area of LGD component than did the lesions of muscularis mucosae (m3) and submucosal layer (sm) cancer (P = 0.037). Mean score for the degrees of cytological abnormalities of LGD component was similar to that of tumor invasive front (P = 0.457) and significantly higher than that of small LGD lesions (P < 0.001). Conclusion:, Our results indicate the possibility that the lesion was formed by a combination of small lesions that arose as a multicentric occurrence of squamous cell carcinoma and dysplasia. Our results also suggest that an LGD component would transform to carcinoma along with tumor progression. However, the concept of ,basal cell layer type carcinoma in situ' may be suitable for squamous cell lesions with a high degree of cytological abnormalities confined to the lower half of the epithelium. [source] Operations Risk Management: Overview of Paul Kleindorfer's ContributionsPRODUCTION AND OPERATIONS MANAGEMENT, Issue 5 2007Morris A. Cohen This paper reviews Paul Kleindorfer's contributions to Operations Management (OM), with a special focus on his research on risk management. An annotated bibliography of selected other contributions reviews the breadth of topics that have occupied Kleindorfer's research attention over his now 45 + years of research. These include optimal control theory, scheduling theory, decision sciences, investment planning and peak load pricing, plus a number of important applications in network industries and insurance. In the area of operations risk management, we review recent work that Kleindorfer and his colleagues in the Wharton Risk Center have undertaken on environmental management and operations, focusing on process safety and environmental risks in the chemical industry. This work is directly related to Kleindorfer's work in the broader area of "sustainable operations", which he, Kal Singhal and Luk Van Wassenhove recently surveyed as part of the new initiative at POMS to encompass sustainable management practices within the POMS community. Continuing in the area of supply chain risks, the paper reviews Kleindorfer's contributions to the development of an integrated framework for contracting and risk hedging for supply management. The emphasis on alignment of pricing, performance and risk management in this framework is presaged in the work undertaken by Kleindorfer and his co-authors in the 1980s on after-sales support services for high-technology products. This work on supply chain risk, and its successors, is reviewed here in light of its growing importance in managing the unbundled and global supply chains characteristic of the new economy. [source] | ||||||||||