Evaluating susceptibility of karst dolines (sinkholes) for collapse in Sango, Tennessee, USA

Dolines or sinkholes are earth depressions that develop in soluble rocks complexes such as limestone, dolomite, gypsum, anhydrite, and halite; dolines appear in a variety of shapes from nearly circular to complex structures with highly curved perimeters. The occurrence of dolines in the studied karst area is not random; they are the results of geomorphic, hydrologic and chemical processes that have caused partial subsidence, even total collapse of the land surface, when voids and caves are present in the bedrock and the regolith arch overbridging these voids is unstable. In the study area, the majority of collapses occur in the regolith (bedrock cover) that bridges voids in the bedrock. Because these collapsing dolines can damage property and cause even the loss of lives, there is a need to develop methods for evaluating karst hazards; such methods can be used by planners and practitioners for urban and economic development, especially in regions with a growing population. The purpose of this project is threefold: 1) to develop a karst feature database, 2) to investigate critical indicators associated with doline collapse, and 3) to design a doline susceptibility model for potential doline collapse based on external morphometric data. The study revealed the presence of short range spatial dependence in the distribution of the dolines’ morphometric parameters such as circularity, geographic orientation of the main doline axes and the length-to-width doline ratios; therefore, geostatistics can be used to spatially evaluate the susceptibility of the karst area for doline collapse using the probability of occurrence of these critical parameters. The partial susceptibility estimates were combined into final spatial probabilities enabling the identification of areas where undetected dolines may cause significant hazards

Soybean isoflavones attenuate the expression of genes related to endometrial cancer risk

Objective We evaluated whether genistein or estrogen treatment has the same effect when administered immediately or late to rats induced with menopause using ovariectomy.Methods Sixty adult female rats were divided into six treatment groups: GI = vehicle immediately after ovariectomy; GII = vehicle 30 days after ovariectomy; GIII = genistein immediately after ovariectomy; GIV = genistein 30 days after ovariectomy; GV = estrogen immediately after ovariectomy; and GVI = estrogen 30 days after ovariectomy. All animals were treated for 30 consecutive days. At the end of the treatment, part of the uteri was removed for subsequent histological studies and another part was used to evaluate estrogen receptors 1 and 2, cell proliferation (cyclin A1 and A2, cyclin D1, cyclin-dependent kinase inhibitors 1, 1B and 2, antigen identified by the monoclonal antibody Ki67) and angiogenesis (vascular endothelial growth factor, VEGF-A) gene expression.Results Late treatment after castration in rats resulted in more developed endometrium, enhanced cell proliferation and estrogen-signalling pathways, particularly the cyclin-related genes Ki67 and VEGF-A, compared to early treatment. Interestingly, these same effects were less intense with genistein compared to those induced by estrogen, especially when genistein was administered late.Conclusion Our data show that isoflavone renders a lower risk of cancer when compared to estrogen in treatments.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Dept Morfol & Genet, BR-04023009 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04023009 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Ctr Dev Expt Models Med & Biol, BR-04023009 São Paulo, SP, BrazilUniv São Paulo, Dept Obstet & Gynecol, BR-05508 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Morfol & Genet, BR-04023009 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04023009 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Ctr Dev Expt Models Med & Biol, BR-04023009 São Paulo, SP, BrazilWeb of Scienc

La longue séquence de Marchésieux: étude pluridisciplinaire du premier cycle glaciaire de l'hémisphère nord

International audienceA l'échelle des cinq derniers millions d'années, les enregistrements paléoclimatiques restitués par les sédiments océaniques illustrent le contrôle des paramètres orbitaux (précession, obliquité et excentricité) sur le climat global. La tendance au refroidissement qui accompagne la fin du Néogène est ainsi marquée, vers -2,4 Ma, par le développement rapide des calottes de glace de l'hémisphère nord (Shackleton et al., 1984), dont les faibles changements de volume entre -2,4 et -0,7 Ma apparaissent dominés par l'obliquité (période de 41 Ka) (Raymo et al., 1989). Après -0,7 Ma, l'amplitude des variations de volume des calottes augmente considérablement et la période dominante de ces variations passe de 41 à 100 ka (Ruddiman et al., 1989). Alors que l'histoire du climat global restituée par les enregistrements océaniques est sans cesse précisée, les données concernant l'évolution des environnements continentaux et côtiers au cours de ces changements restent essentiellement fragmentaires. Le forage effectué à Marchésieux (Manche; Normandie) à permis de réaliser une étude pluridisciplinaire de la signature continentale de ce premier cycle glaciaire de l'hémisphère nord