42 research outputs found
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Development of the Community Water Model (CWatM v1.04) – a high-resolution hydrological model for global and regional assessment of integrated water resources management
We develop a new large-scale hydrological and water resources model, the Community Water Model (CWatM), which can simulate hydrology both globally and regionally at different resolutions from 30 arcmin to 30 arcsec at daily time steps. CWatM is open source in the Python programming environment and has a modular structure. It uses global, freely available data in the netCDF4 file format for reading, storage, and production of data in a compact way. CWatM includes general surface and groundwater hydrological processes but also takes into account human activities, such as water use and reservoir regulation, by calculating water demands, water use, and return flows. Reservoirs and lakes are included in the model scheme. CWatM is used in the framework of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), which compares global model outputs. The flexible model structure allows for dynamic interaction with hydro-economic and water quality models for the assessment and evaluation of water management options. Furthermore, the novelty of CWatM is its combination of state-of-the-art hydrological modeling, modular programming, an online user manual and automatic source code documentation, global and regional assessments at different spatial resolutions, and a potential community to add to, change, and expand the open-source project. CWatM also strives to build a community learning environment which is able to freely use an open-source hydrological model and flexible coupling possibilities to other sectoral models, such as energy and agriculture
Antithymocyte Globulin in Reduced-Intensity Conditioning Regimen Allows a High Disease-Free Survival Exempt of Long-Term Chronic Graft-versus-Host Disease
AbstractNonmyeloablative (NMA) regimens allow the use of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients considered unfit for standard myeloablative conditioning (MAC) regimens using high-dose alkylating agents with or without total body irradiation (TBI). Reduced-intensity conditioning (RIC) regimens, based on fludarabine (Flu), busulfan (Bu), and rabbit antithymocyte globulin (r-ATG), represent an intermediate alternative between NMA and MAC regimens. This platform was subsequently optimized by the introduction of i.v. Bu and the use of 5 mg/kg r-ATG, based on the hypothesis that these modifications would improve the safety of RIC allo-HSCT. Here we report a study conducted at our institution on 206 patients, median age 59 years, who underwent allo-HSCT after conditioning with Flu, 2 days of i.v. Bu, and 5 mg/kg r-ATG (FBx-ATG) between 2005 and 2012. The prevalence of grade III-IV acute graft-versus-host disease (GVHD) was 9%, and that of extensive chronic GVHD was 22%. Four-year nonrelapse mortality (NRM), relapse, and overall survival (OS) rates were 22%, 36%, and 54%, respectively. NRM tended to be influenced by comorbidities (hematopoietic cell transplantation–specific comorbidity index [HCT-CI] <3 versus HCT-CI ≥3: 18% versus 27%; P = .075), but not by age (<60 years, 20% versus ≥60 years, 25%; P = .142). Disease risk significantly influenced relapse (2 years: low, 8%, intermediate, 28%, high, 34%; very high, 63%; P = .017). Both disease risk (hazard ratio [95% confidence interval]: intermediate, 2.1 [0.8 to 5.2], P = .127; high, 3.4 [1.3 to 9.1], P = .013; very high, 4.0 [1.1 to 14], P = .029) and HCT-CI (hazard ratio [95% confidence interval]: HCT-CI ≥3, 1.7 (1.1 to 2.8), P = .018) influenced OS, but age and donor type did not. The FBx-ATG RIC regimen reported here is associated with low mortality and high long-term disease-free survival without persistent GVHD in both young and old patients. It represents a valuable platform for developing further post-transplantation strategies aimed at reducing the incidence of relapse, particularly in the setting of high-risk disease
COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study
Background:
The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms.
Methods:
International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms.
Results:
‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country.
Interpretation:
This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
How to model groundwater systems in the hydrological cycle? : an approach at different scales with different observed data types
Les systèmes aquifères constituent la partie souterraine du cycle hydrologique. Ils transfèrent les pluies infiltrées à travers les sols sur des distances variables. Après un temps caractéristique de l’ordre du mois au millier d’années, les eaux souterraines regagnent la surface en alimentant les rivières et en satisfaisant en partie l’évapotranspiration. Les aquifères sont ainsi une ressource en eau majeure pour l’Homme et les écosystèmes. La prédiction de leur réponse aux pressions anthropiques et climatiques se heurte à deux difficultés (1) la faible densité d’informations directes sur les milieux géologiques et leur grande hétérogénéité (2) la complexité des échanges entre la surface et la profondeur. L’enjeu est donc de développer des modèles représentant au mieux les processus aux différentes échelles spatiotemporelles. Pour aborder cette question, nous étudions le contenu informatif de différents types d’observables (piézométrie, débit de rivière, déformation de surface...) afin de déterminer comment ils peuvent améliorer la paramétrisation des modèles. Notre travail s’appuie sur la modélisation hydrologique du site de Ploemeur (échelle locale) et du bassin du Rhin (échelle continentale). Dans les deux cas, des modèles simples sont développés en utilisant des solutions analytiques et numériques. Le modèle ModFlow a également été couplé à un modèle hydrologique. À petite échelle, les résultats illustrent l’intérêt de différents types de données transitoires pour contraindre les processus. À grande échelle, le modèle développé ainsi que les observables permettent d’affiner le rôle des systèmes aquifères dans la disponibilité de l’eau en surface. Les deux approches illustrent un contrôle des flux à différentes échelles par la topographie, la géologie et l’hétérogénéité.Groundwater systems (GW) constitute an important part of the hydrological cycle. GW transfer water infiltrated through soils on variable distances. After a characteristic time ranging from the month to thousand of years, GW reach the surface supporting rivers and evapotranspiration. Thus, they are a major resource for human and ecosystems. PredictingGWresponse to human and climate pressures is limited by (1) the scarcity of direct information on the highly heterogeneous geological media (2) the complexity of surface-depth exchanges. So, it seems necessary to develop models representing at best the processes at different spatiotemporal scales. To address this issue, we study the informative content of different observation types (piezometry, streamflow, surface deformation. . . ) to assess how they can improve models parametrization. Our work is based on GW modeling of the Ploemeur site (local scale) and of the Rhine basin (continental scale). For both approaches, simple models are developed, using analytical or numerical solutions. Also, the ModFlow model was coupled to an hydrological model. At small scale, results show the interest of temporal and multidisciplinary data to better constrain processes. At large scale, the developed model, as well as observations, allows to precise the role ofGWfor water availability on surface. Both approaches highlight a flows control at different scales by topography, geology and heterogeneity
Comment modéliser les systèmes aquifères au sein du cycle hydrologique ? : une approche « multi-observables » à différentes échelles
Groundwater systems (GW) constitute an important part of the hydrological cycle. GW transfer water infiltrated through soils on variable distances. After a characteristic time ranging from the month to thousand of years, GW reach the surface supporting rivers and evapotranspiration. Thus, they are a major resource for human and ecosystems. PredictingGWresponse to human and climate pressures is limited by (1) the scarcity of direct information on the highly heterogeneous geological media (2) the complexity of surface-depth exchanges. So, it seems necessary to develop models representing at best the processes at different spatiotemporal scales. To address this issue, we study the informative content of different observation types (piezometry, streamflow, surface deformation. . . ) to assess how they can improve models parametrization. Our work is based on GW modeling of the Ploemeur site (local scale) and of the Rhine basin (continental scale). For both approaches, simple models are developed, using analytical or numerical solutions. Also, the ModFlow model was coupled to an hydrological model. At small scale, results show the interest of temporal and multidisciplinary data to better constrain processes. At large scale, the developed model, as well as observations, allows to precise the role ofGWfor water availability on surface. Both approaches highlight a flows control at different scales by topography, geology and heterogeneity.Les systèmes aquifères constituent la partie souterraine du cycle hydrologique. Ils transfèrent les pluies infiltrées à travers les sols sur des distances variables. Après un temps caractéristique de l’ordre du mois au millier d’années, les eaux souterraines regagnent la surface en alimentant les rivières et en satisfaisant en partie l’évapotranspiration. Les aquifères sont ainsi une ressource en eau majeure pour l’Homme et les écosystèmes. La prédiction de leur réponse aux pressions anthropiques et climatiques se heurte à deux difficultés (1) la faible densité d’informations directes sur les milieux géologiques et leur grande hétérogénéité (2) la complexité des échanges entre la surface et la profondeur. L’enjeu est donc de développer des modèles représentant au mieux les processus aux différentes échelles spatiotemporelles. Pour aborder cette question, nous étudions le contenu informatif de différents types d’observables (piézométrie, débit de rivière, déformation de surface...) afin de déterminer comment ils peuvent améliorer la paramétrisation des modèles. Notre travail s’appuie sur la modélisation hydrologique du site de Ploemeur (échelle locale) et du bassin du Rhin (échelle continentale). Dans les deux cas, des modèles simples sont développés en utilisant des solutions analytiques et numériques. Le modèle ModFlow a également été couplé à un modèle hydrologique. À petite échelle, les résultats illustrent l’intérêt de différents types de données transitoires pour contraindre les processus. À grande échelle, le modèle développé ainsi que les observables permettent d’affiner le rôle des systèmes aquifères dans la disponibilité de l’eau en surface. Les deux approches illustrent un contrôle des flux à différentes échelles par la topographie, la géologie et l’hétérogénéité
Long-term hydraulic behavior of heterogeneous aquifers under transient conditions
International audienceWith the increasing anthropic and climatic pressure on water resources, knowledge of recharge mechanisms andwater transfer is of major importance to better understand destabilization of natural hydrological systems to facepossible evolutions in the future. The equivalent response of a groundwater system is generally interpreted ascomplex, non-linear and hysteretic. Another point of view would consider the current response as the superpositionof numerous transient events in a complex medium, which necessarily depends on the past trajectory of the GWand boundary conditions.Here, we present a multidisciplinary approach to better model long-term system behavior under anthropic andclimatic destabilization. Several parsimonious analytical and numerical models were derived considering severalflow structures and boundary conditions. These models are set up on a pluri-kilometric aquifer system in fracturedcontext on the Ploemeur site (Britany, H+ hydrogeological) and constrained by various long-term observationssuch as hydraulic, chemical and deformation data. Two neighboring systems in a similar geological context arecompared; one being pumped at a rate of 1.1 Mm3/year since 1991, the other one is still in a natural state. Ourmodels could predict the long-term behavior of hydrological systems and estimate the water balance perturbationand natural flows re-distribution induced by pumping. We show importance of multiple observation types to yieldbetter predictions and the critical importance to represent boundary conditions for GW management
Comportement à long terme d’un aquifèrehétérogène dans des conditions transitoires
National audienceAvec l’augmentation de la consommation en eau, la connaissancedes mécanismes de recharge dans les aquifères hétérogènesdevient d’une importance majeure. En particulier il est nécessairede comprendre comment la pression anthropique et les variationsclimatiques déstabilisent les systèmes naturels afin de faire face àune possible évolution dans le temps. La réponse équivalente d’unsystème aquifère est généralement interprétée comme complexe,non-linéaire et hystérétique. Un autre point de vue considérerait laréponse actuelle comme la superposition de nombreux événementstransitoires en milieu complexe et donc dépendante de l’état passéde l’aquifère et des conditions limites.Ici, nous présentons une méthode pour modéliser et caractériserl’impact à long terme des déstabilisations anthropiques et climatiques.En effet l’état actuel d’un aquifère peut se reconstruirecomme l’impact cumulé des anciennes conditions limites, qui sontnaturellement considérées comme non-stationnaires. Nous présentonsplusieurs modèles semi-analytiques et numériques basés surdifférents types de conditions aux limites.Ces modèles sont employés pour interpréter la réponse hydrauliqued’un système aquifère plurikilométrique en domaine fracturé, ense basant sur 25 ans de données piézométriques. Le terrain expérimentalfait partie du réseau SOERE (H+) et se situe à Ploemeur(Morbihan). Deux systèmes en contexte géologique similairesont comparés, l’un étant pompé à un débit de 1,1 Mm3/andepuis 1991, l’autre demeurant encore à l’état naturel. Nosmodèles pourraient prédire le comportement des systèmes hydrogéologiquesen réponse à la variabilité climatique et estimer laperturbation du bilan hydrologique et des flux naturels engendréspar les pompages. L’accent est mis sur l’importance d’intégrer lecaractère transitoire des processus dans la modélisation des systèmespour une gestion précise des ressources d’eau souterraine.Nous montrons également le rôle prépondérant des conditions limitessur l’hétérogénéité des aquifères
On the co-evolution of geodetic observations and Earth System Models
International audienceWhile surface freshwater storage components are easily observable components of our landscapes, a major partof continental water resides and flow below ground in groundwater systems (GW) and is broadly inaccessible todirect observations. GW sustain ecosystems with high quality freshwater, support food security, however, they arehardly represented within global land models. The main difficulties lie in the long response time of GW and thecomplexity water flow within heterogeneous geological layers.In this presentation, we show how geodesy, i.e. the study of the Earth’s shape and gravity field, can support theimplementation of GW within models. First, gravity observations from GRACE have revolutionized our vision ofthe water cycle, by its sensitivity to total water storage changes. Another fundamental processes lies in the physicalinteractions between water and rock: fluid pressure gradients is the engine for water flow, but also generate adeformation that is measurable at the surface with current geodetic tools (GPS). New opportunities also emergewith the development of seismic noise monitoring, highly sensitive water pressure changes. All these instrumentsprovide valuable information on shallow and confined GW storage changes and contribution to water cycle, on avariety of spatial scales, from 10 km to 1000s km scales. Considering the development of dense internationalnetworks (GPS, seismic stations), and new satellite missions (InSAR from Sentinel, GRACE-FO), there is a wideopportunity to improve the representation of GW within global models.We support the analysis with recent examples at all scales, and show the link between the current knowledge ofwater flow and geodetic analyses. While a goal of the geodesy is to provide independent measures of the watercycle, it is clear that an iterative analysis is the most effective. It is anticipated that global models will guide theformulation of geodetic water storage variation estimates as, in turn; geodetic estimates will contribute to globalhydrological modeling
Frequency domain water table fluctuations reveal impacts of intense rainfall and vadose zone thickness on groundwater recharge
Groundwater recharge is difficult to estimate, especially in fractured aquifers, because of the spatial variability of the soil properties and because of the lack of data at basin scale. A relevant method, known as the water table fluctuation (WTF) method, consists in inferring recharge directly from the WTFs observed in boreholes. However, the WTF method neglects the impact of lateral groundwater redistribution in the aquifer; i.e., it assumes that all the WTFs are attributable to recharge. In this study, we developed the WTF approach in the frequency domain to better consider groundwater lateral flow, which quickly redistributes the impulse of recharge and mitigates the link between WTFs and recharge. First, we calibrated a 1D analytical groundwater model to estimate hydrodynamic parameters at each borehole. These parameters were defined from the WTFs recorded for several years, independently of prescribed potential recharge. Second, calibrated models are reversed analytically in the frequency domain to estimate recharge fluctuations (RFs) at weekly to monthly scales from the observed WTFs. Models were tested on two twin sites with a similar climate, fractured aquifer and land use but different hydrogeologic settings: one has been operated as a pumping site for the last 25 years (Ploemeur, France), while the second has not been perturbed by pumping (Guidel). Results confirm the important role of rainfall temporal distribution in generating recharge. While all rainfall contributes to recharge, the ratio of recharge to rainfall minus potential evapotranspiration is frequency-dependent, varying between 20 %–30 % at periods <10 d and 30 %–50 % at monthly scale and reaching 75 % at seasonal timescales. We further show that the unsaturated zone thickness controls the intensity and timing of RFs. Overall, this approach contributes to a better assessment of recharge and helps to improve the representation of groundwater systems within hydrological models. In spite of the heterogeneous nature of aquifers, parameters controlling WTFs can be inferred from WTF time series, providing confidence that the method can be deployed in different geological contexts where long-term water table records are available