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In der vorliegenden Arbeit wurde mit der Entwicklung einer differentiellen Turbulenzsäule das advektionsfreie Turbulenzprofil einer offenen Gerinneströmung im Labor nachgebildet. Hierin konnten die Prozesse der Feinsedimentdynamik nachgebildet und gemessen werden. Die Ergebnisse beschreiben den Prozessablauf in der Feinsedimentdynamik und dienten als Grundlage für die Entwicklung und Validierung eines Modells zur Bilanzierung der Feinsedimentdynamik in der Wassersäule.

Feinsediment, Sediment, Turbulenz, Aggregation, Sedimentation

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Cet ouvrage est le fruit de l’une des premières « expertises collégiales » coordonnées par l’Institut de recherche pour le développement (IRD). Il fait le bilan des connaissances sur la présence, préoccupante, du mercure en Amazonie, sur ses effets sur l’environnement et la santé. Il se conclut par un certain nombre de recommandations opérationnelles. Il existe deux modes spécifiques de contamination humaine par le mercure : l’exposition des travailleurs de l’or (orpailleurs ou raffineurs) aux vapeurs de mercure dégagées lors des opérations d’enrichissement du minerai aurifère et de purification des lingots ; l’exposition de la population à un dérivé du mercure, le méthylmercure, principalement par la consommation de poissons eux-mêmes contaminés. Le premier mode, direct, de contamination peut entraîner des troubles de la santé du fait d’expositions prolongées et répétées. Ceux-ci concernent les voies respiratoires, le système gastro-intestinal et le système nerveux central, ce dernier pouvant être l’objet d’altérations irréversibles. Le caractère souvent clandestin et précaire des activités d’orpaillage ne favorise pas l’usage de techniques qui éviteraient ou du moins réduiraient cette contamination. La seconde forme d’exposition est beaucoup plus difficile encore à maîtriser. La méthylation du mercure, issu de l’orpaillage mais aussi contenu dans les sols à l’état « naturel », relève d’activités bactériennes dans des milieux aquatiques privés d’oxygène et riches en matière organique. L’exportation du mercure est facilitée par la déforestation – les sols dénudés favorisent sa libération – et par l’aptitude de ce métal à se complexer aux fines suspensions argilo-organiques véhiculées par les eaux. La contamination des poissons est l’étape suivante de la chaîne de transfert vers l’homme : comme, pour beaucoup de populations amazoniennes, leur consommation représente la source essentielle de protéines, elle constitue un agent d’exposition quasi quotidienne au méthylmercure dans l’ensemble de l’Amazonie et non dans les seules régions d’orpaillage. Cette imprégnation continue entraîne essentiellement l’apparition, tant chez l’adulte que chez l’enfant, d’atteintes neurologiques sévères, plus graves encore chez le fœtus au moment de la formation des organes. À partir de ces constats, un certain nombre de recommandations sont avancées : la mise en place d’un observatoire amazonien de surveillance, la création d’une structure d’encadrement de l’orpaillage, l’usage généralisé d’équipements de protection contre les vapeurs de mercure, diverses mesures techniques destinées à réduire l’impact du mercure dans l’environnement, une meilleure diffusion de l’information de base sur les risques encourus, l’adoption d’habitudes alimentaires prévenant l’exposition régulière au méthylmercure, une amélioration des suivis sanitaires.

mercure --- toxicité --- contamination --- cycle biogéochimique --- eau continentale --- sédimentation lacustre --- exploitation du sous-sol --- mine --- or --- santé publique --- groupe à risque (santé publique) --- Amazonie --- Brésil --- Guyane française

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Climate and anthropogenic changes impact the conditions of erosion and sediment transport in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes in natural areas, as well as in cultivated areas, and, sometimes, in degraded areas and desertified landscapes. These anthropogenized landscapes are more sensitive to erosion. On the other hand, the increase in the number of dams in watersheds traps a great portion of sediment fluxes, which do not reach the sea in the same amount, nor at the same quality, with consequences on coastal geomorphodynamics. This book is dedicated to studies on sediment fluxes from continental areas to coastal areas, as well as observation, modeling, and impact analysis at different scales from watershed slopes to the outputs of large river basins. This book is concentrated on a number of keywords: “erosion” and “sediment transport”, “model” and “practice”, and “change”. The keywords are briefly discussed with respect to the relevant literature. The contributions in this book address observations and models based on laboratory and field data, allowing researchers to make use of such resources in practice under changing conditions.

GSD --- proglacial channels --- bedload transport --- field measurements --- fluvial erosion --- soil slurry --- sedimentation --- two-phase flow --- transfer --- deposition --- limiting tractive force --- Wadi Mina --- Algeria --- sediment --- ruptures --- SMBA Dam --- specific degradation --- Mediterranean Maghreb Basin --- water fluxes --- sediment fluxes --- reservoirs --- hillside reservoirs --- sediment retention --- soil erosion --- rill development --- erosion topography --- sloping flume experiments --- climate change --- human activities --- soil erosion --- SWAT model --- Xihe River Basin --- runoff --- suspended sediment --- phosphorus --- water quality modelling --- mitigation measures --- flooding --- incipient deposition --- sediment transport --- self-cleansing --- sewer systems --- shear stress --- urban drainage system --- aggradation --- CCHE1D --- climate change --- degradation --- dynamical downscaling --- flow discharge --- migration --- riverbed --- sediment --- bed load transport --- shear Reynolds number --- mixed-size bed material --- complex morphodynamics --- soil loss --- sediment delivery --- erosion modelling --- environmental change --- agriculture --- Czech Republic --- Anthropocene --- climate change --- deposition --- erosion --- modeling --- practice --- sedimentation --- sediment transport --- watershed

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The development of micro- and nanodevices for blood analysis is an interdisciplinary subject that demands the integration of several research fields, such as biotechnology, medicine, chemistry, informatics, optics, electronics, mechanics, and micro/nanotechnologies. Over the last few decades, there has been a notably fast development in the miniaturization of mechanical microdevices, later known as microelectromechanical systems (MEMS), which combine electrical and mechanical components at a microscale level. The integration of microflow and optical components in MEMS microdevices, as well as the development of micropumps and microvalves, have promoted the interest of several research fields dealing with fluid flow and transport phenomena happening in microscale devices. Microfluidic systems have many advantages over their macroscale counterparts, offering the ability to work with small sample volumes, providing good manipulation and control of samples, decreasing reaction times, and allowing parallel operations in one single step. As a consequence, microdevices offer great potential for the development of portable and point-of-care diagnostic devices, particularly for blood analysis. Moreover, the recent progress in nanotechnology has contributed to its increasing popularity, and has expanded the areas of application of microfluidic devices, including in the manipulation and analysis of flows on the scale of DNA, proteins, and nanoparticles (nanoflows). In this Special Issue, we invited contributions (original research papers, review articles, and brief communications) that focus on the latest advances and challenges in micro- and nanodevices for diagnostics and blood analysis, micro- and nanofluidics, technologies for flow visualization, MEMS, biochips, and lab-on-a-chip devices and their application to research and industry. We hope to provide an opportunity to the engineering and biomedical community to exchange knowledge and information and to bring together researchers who are interested in the general field of MEMS and micro/nanofluidics and, especially, in its applications to biomedical areas.

cell analysis --- lens-less --- microfluidic chip --- twin-image removal --- POCT --- red blood cell (RBC) aggregation --- multiple microfluidic channels --- master molder using xurography technique --- RBC aggregation index --- modified conventional erythrocyte sedimentation rate (ESR) method --- regression analysis --- biomicrofluidics --- red blood cells --- deformability --- velocity --- centrifugal microfluidic device --- CEA detection --- density medium --- fluorescent chemiluminescence --- multinucleated cells --- XTC-YF cells --- morphological analysis --- Y-27632 --- hydrophobic dish --- red blood cells --- Lattice–Boltzmann method --- finite element method --- immersed boundary method --- narrow rectangular microchannel --- computational biomechanics --- microfluidics --- mechanophenotyping --- cancer --- metastatic potential --- cell adhesion --- biomedical coatings --- microfabrication --- computational fluid dynamics --- microfluidics --- microfluidics --- red blood cells (RBCs) --- microfabrication --- polymers --- separation and sorting techniques --- microfluidic devices --- cell deformability --- chronic renal disease --- diabetes --- red blood cells (RBCs) --- hyperbolic microchannel --- blood on chips --- suspension --- rheology --- power-law fluid --- circular microchannel --- pressure-driven flow --- particle tracking velocimetry --- microstructure --- n/a

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The interface of 440,000 km long coastline in the world is subject to global change, with an increasing human pressure (land use, buildings, sand mining, dredging) and increasing population. Improving our knowledge on involved mechanisms and sediment transport processes, monitoring the evolution of sedimentary stocks and anticipating changes in littoral and coastal zones is essential for this purpose. The special issue of Water on “Sediment transport in coastal waters” gathers thirteen papers which introduce the current revolution in the scientific research related to coastal and littoral hydrosedimentary dynamics, and reflect the diversity of concerns on which research in coastal sediment transport is based, and current trends — topics and preferred methods — to address them.

suspended sediment --- sediment transport --- coastal hydraulics --- Mekong --- river plume --- monsoon --- mathematical model --- geochemical map --- particle transfer process --- tidal current --- analysis of variance (ANOVA) --- Cluster analysis --- Mahalanobis’ generalized distances --- Seto Inland Sea --- East Coast Low --- nearshore processes --- coastal erosion --- coastal management --- climate change --- numerical modelling --- Southeast Australia --- soil erosion --- SWAT --- water scarcity --- sediment transport modelling --- Tafna catchment --- North Africa --- suspended sediment --- sediment transport --- lagoon --- geochemistry --- Ni mining --- sediment trap --- hydrodynamics --- New Caledonia --- dry season --- Senegal River delta --- Langue de Barbarie spit --- delta vulnerability --- river-mouth migration --- spit breaching --- ERA hindcast waves --- longshore sediment transport --- Vietnam --- South China Sea --- erosion --- recovery --- storminess --- winter monsoon --- typhoons --- shoreline --- waves forcing --- storms --- resilience --- post-storm recovery --- Bight of Benin --- seasonal cycle --- trend --- sand-mud mixture erosion --- numerical modelling --- non-cohesive to cohesive transition --- remote sensing reflectance --- turbidity --- seagrass beds --- bed shear stress --- fresh water runoff --- oceanic water intrusion --- suspended particulate matter --- aggregates --- flocculation --- biomass --- sediment --- turbidity --- remote-sensing --- MODerate Resolution Imaging Spectroradiometer (MODIS) --- Support Vector Regression (SVR) --- oligotrophic lagoon --- bathymetry --- reflectance --- seabed colour --- coral reef --- New Caledonia --- sediment transport --- cohesive sediments --- non cohesive sediments --- sand --- mud --- coastal erosion --- sedimentation --- morphodynamics --- suspended particulate matter --- bedload