The effect of continuous venovenous hemofiltration on neutrophil gelatinase-associated lipocalin plasma levels in patients with septic acute kidney injury

International audienceCe texte d’introduction au dossier de Flux 2017/2 (N° 108) questionne l’émergence de la thématique de la circularité des matières dans les politiques publiques urbaines contemporaines. Les articles ont en commun de porter une attention minutieuse à la matérialité des flux qui traversent et constituent la ville et aux objets sociaux qui la composent. Ils analysent les modalités et les conséquences de leur mise en circulation, ainsi que les régulations et les conflits qui l’accompagnent. Que l’ensemble des articles traite de pratiques et de politiques ancrées dans l’espace de la région de Lyon résulte moins d’une volonté monographique que d’une rencontre en partie fortuite. Mais cela souligne en tout cas l’importance d’une approche toujours attentive aux faits géographiques et aux effets de lieu dans la diversité de leurs échelles. Trois thématiques transversales sont présentes : d’abord, en identifiant de nouvelles ressources, les articles permettent de réfléchir à l’invention et à la construction de nouveaux circuits pour les matières. Ensuite, la régulation de ces circuits implique l’identification de nouveaux acteurs et la mise en place de nouvelles formes de relations avec les producteurs et gestionnaires des matières, formant donc l’espace d’une gouvernance renouvelée. Enfin, si ces circuits se structurent dans un espace qui est celui de la proximité géographique, ils s’inscrivent néanmoins dans une logique relationnelle qui ne cesse de questionner les normes et les échelles. Ce numéro permet ainsi de nuancer et de re-matérialiser les injonctions à faire advenir l’économie circulaire dans les villes

Late Cretaceous–earliest Paleogene deformation in the Longmen Shan fold-and-thrust belt, eastern Tibetan Plateau margin: pre-Cenozoic thickened crust?

This study presents structural and 40Ar/39Ar geochronological data from the southern part of the Longmen Shan fold-and-thrust belt that forms the eastern margin of the Tibetan Plateau. Investigations focused on hinterland ductile top-to-the-WNW shear deformation, which has been linked previously to late Cenozoic lower crustal flow. Consistent with previous studies, the sense of deformation is mapped as top-to-the-WNW in the Longmen Shan hinterland. The timing of the deformation is constrained by 40Ar/39Ar geochronological data of recrystallized minerals aligned along the shear foliation as Late Cretaceous–earliest Paleogene, thus predating the inferred late Cenozoic crustal flow. This deformation is contemporaneous with SE verging thrusting and loading along the Longmen Shan front, which formed a coeval ~2–3 km thick foredeep sequence along the southwestern margin of the Sichuan Basin. In the context of the regional geology, this tectonic configuration could result from either extrusion of a crustal wedge or back thrust in a duplex. Compared to other orogens, where similar crustal configurations have been reported, it is speculated that the eastern Tibetan Plateau margin acquired thickened crust and highly elevated topography in Late Cretaceous–earliest Paleogene time

Thermal Conductivity Estimation Based on Well Logging

The thermal conductivity of a stratum is a key factor to study the deep temperature distribution and the thermal structure of the basin. A huge expense of core sampling from boreholes, especially in offshore areas, makes it expensive to directly test stratum samples. Therefore, the use of well logging (the gamma-ray, the neutron porosity, and the temperature) to estimate the thermal conductivity of the samples obtained from boreholes could be a good alternative. In this study, we measured the thermal conductivity of 72 samples obtained from an offshore area as references. When the stratum is considered to be a shale–sand–fluid model, the thermal conductivity can be calculated based on the mixing models (the geometric mean and the square root mean). The contents of the shale and the sand were derived from the natural gamma-ray logs, and the content of the fluid (porosity) was derived from the neutron porosity logs. The temperature corrections of the thermal conductivity were performed for the solid component and the fluid component separately. By comparing with the measured data, the thermal conductivity predicted based on the square root model showed good consistency. This technique is low-cost and has great potential to be used as an application method to obtain the thermal conductivity for geothermal research

A Method for Determining Target Areas of Hot Dry Rock Resources: A Case Study in Continental China

Geothermal resources have been recognized as important sources of clean renewable energy. The exploration, development, and utilization of geothermal resources, especially hot dry rock (HDR) resources, are highly important for achieving peak carbon and carbon neutrality. However, there is no comprehensive evaluation method for determining HDR target areas, and the evaluation scale and application disciplines are relatively simplistic. In this paper, we sought to optimize the identification of HDR target areas through a multiscale and multidisciplinary method and formed a set of generalized and demonstrative processes to guide the exploration of HDR resources. Through practical application to the Gonghe Basin and the Zhangzhou Basin, it was found that the comprehensive geothermal conditions of the Gonghe Basin are superior to those of the Zhangzhou Basin, and the geothermal reservoir depth, geothermal reservoir temperature, geothermal gradient, and heat flow are the four most important factors affecting hot dry rock geothermal resources. Using this method, the prioritization of target areas changes from a qualitative study to a quantitative and semiquantitative study, increasing the specificity and reliability of the decision-making process