15 research outputs found
LakeCC: a tool for efficiently identifying lake basins with application to palaeogeographic reconstructions of North America
Along the margins of continental ice sheets, lakes formed in isostatically depressed basins duringglacial retreat. Their shorelines and extent are sensitive to the ice margin and the glacial history of the region.Proglacial lakes, in turn, also impact the glacial isostatic adjustment due to loading, and ice dynamics by posing amarineâlike boundary condition at the ice margin. In this study we present a tool that efficiently identifies lake basinsand the corresponding maximum water level for a given ice sheet and topography reconstruction. This algorithm,called the LakeCC model, iteratively checks the whole map for a set of increasing water levels and fills isolated basinsuntil they overflow into the ocean. We apply it to the presentâday Great Lakes and the results show good agreement(âŒ1â4%) with measured lake volume and depth. We then apply it to two topography reconstructions of NorthAmerica between the Last Glacial Maximum and the present. The model successfully reconstructs glacial lakes suchas Lake Agassiz, Lake McConnell and the predecessors of the Great Lakes. LakeCC can be used to judge the quality ofice sheet reconstructions
LakeCC: a tool for efficiently identifying lake basins with application to palaeogeographic reconstructions of North America
Groundwater Buffers Decreasing Glacier Melt in an Andean WatershedâBut Not Forever
©2019. The Authors. Accelerating mountain glacier recession in a warming climate threatens the sustainability of mountain water resources. The extent to which groundwater will provide resilience to these water resources is unknown, in part due to a lack of data and poorly understood interactions between groundwater and surface water. Here we address this knowledge gap by linking climate, glaciers, surface water, and groundwater into an integrated model of the Shullcas Watershed, Peru, in the tropical Andes, the region experiencing the most rapid mountain-glacier retreat on Earth. For a range of climate scenarios, our model projects that glaciers will disappear by 2100. The loss of glacial meltwater will be buffered by relatively consistent groundwater discharge, which only receives minor recharge (~2%) from glacier melt. However, increasing temperature and associated evapotranspiration, alongside potential decreases in precipitation, will decrease groundwater recharge and streamflow, particularly for the RCP 8.5 emission scenario
Marine-calibrated chronology of southern Laurentide Ice Sheet advance and retreat: ~2000-year cycles paced by meltwater-climate feedback
Late Pleistocene glacial transitions in North America altered major river drainages, as revealed by deep-sea sediment
Small intestinal presentation of nodular lymphocyte-predominant Hodgkin lymphoma with T cell/histiocyte-rich B cell lymphoma-like areasâwith review of literature on extranodal presentation of this disease
Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), accounts for âŒ5% of all cases of Hodgkin lymphoma and is characterized by involvement of the peripheral lymph nodes. NLPHL occurs in young adults and is associated with frequent relapses. In 3% to 7% of cases, NLPHL progresses to a diffuse large B cell lymphoma. Furthermore, a proportion of NLPHL also have areas with features of T cell/histiocyte-rich large B cell lymphoma (THRLBCL), either at presentation or on follow-up. Here, we describe a 32-year-old man who presented to the emergency department with small bowel perforation. The resected small bowel showed full-thickness mural ulceration and involvement by a lymphoma with features of NLPHL that also had areas resembling THRLBCL. The patient had axillary lymphadenopathy, biopsy of which showed NLPHL with focal THRLBCL-like areas. Such a lymphoma presenting as small intestinal lesion/perforation has not been reported in the literature before. We take this opportunity to review the literature on extranodal presentations of NLPHL and discuss the natural history of this disease