31 research outputs found
Gaussian Anamorphosis for Ensemble Kalman Filter Analysis of SAR-Derived Wet Surface Ratio Observations
Flood simulation and forecast capability have been greatly improved thanks to
advances in data assimilation (DA) strategies incorporating various types of
observations; many are derived from spatial Earth Observation. This paper
focuses on the assimilation of 2D flood observations derived from Synthetic
Aperture Radar (SAR) images acquired during a flood event with a dual
state-parameter Ensemble Kalman Filter (EnKF). Binary wet/dry maps are here
expressed in terms of wet surface ratios (WSR) over a number of subdomains of
the floodplain. This ratio is further assimilated jointly with in-situ
water-level observations to improve the flow dynamics within the floodplain.
However, the non-Gaussianity of the observation errors associated with
SAR-derived measurements break a major hypothesis for the application of the
EnKF, thus jeopardizing the optimality of the filter analysis. The novelty of
this paper lies in the treatment of the non-Gaussianity of the SAR-derived WSR
observations with a Gaussian anamorphosis process (GA). This DA strategy was
validated and applied over the Garonne Marmandaise catchment (South-west of
France) represented with the TELEMAC-2D hydrodynamic model, first in a twin
experiment and then for a major flood event that occurred in January-February
2021. It was shown that assimilating SAR-derived WSR observations, in
complement to the in-situ water-level observations significantly improves the
representation of the flood dynamics. Also, the GA transformation brings
further improvement to the DA analysis, while not being a critical component in
the DA strategy. This study heralds a reliable solution for flood forecasting
over poorly gauged catchments thanks to available remote-sensing datasets.Comment: 19 pages, 13 figures. Submitted to the IEEE Transactions on
Geoscience and Remote Sensin
Enhancing Flood Forecasting with Dual State-Parameter Estimation and Ensemble-based SAR Data Assimilation
Hydrodynamic
Reducing Uncertainties of a Chained Hydrologic-hydraulic Model to Improve Flood Forecasting Using Multi-source Earth Observation Data
The challenges in operational flood forecasting lie in producing reliable
forecasts given constrained computational resources and within processing times
that are compatible with near-real-time forecasting. Flood hydrodynamic models
exploit observed data from gauge networks, e.g. water surface elevation (WSE)
and/or discharge that describe the forcing time-series at the upstream and
lateral boundary conditions of the model. A chained hydrologic-hydraulic model
is thus interesting to allow extended lead time forecasts and overcome the
limits of forecast when using only observed gauge measurements. This research
work focuses on comprehensively reducing the uncertainties in the model
parameters, hydraulic state and especially the forcing data in order to improve
the overall flood reanalysis and forecast performance. It aims at assimilating
two main complementary EO data sources, namely in-situ WSE and SAR-derived
flood extent observations.Comment: Copyright 2023 IEEE. Published in the IEEE 2023 International
Geoscience & Remote Sensing Symposium (IGARSS 2023), scheduled for July 16 -
21, 2023 in Pasadena, California, US
Famílies botàniques de plantes medicinals
Facultat de Farmàcia, Universitat de Barcelona. Ensenyament: Grau de Farmàcia, Assignatura: Botànica Farmacèutica, Curs: 2013-2014, Coordinadors: Joan Simon, Cèsar Blanché i
Maria Bosch.Els materials que aquí es presenten són els recull de 175 treballs d’una família botànica d’interès medicinal realitzats de manera individual. Els treballs han estat realitzat
per la totalitat dels estudiants dels grups M-2 i M-3 de l’assignatura Botànica Farmacèutica
durant els mesos d’abril i maig del curs 2013-14. Tots els treballs s’han dut a terme a través de la plataforma de GoogleDocs i han estat tutoritzats pel professor de l’assignatura i revisats i finalment co-avaluats entre els propis estudiants. L’objectiu principal de l’activitat ha estat fomentar l’aprenentatge autònom i col·laboratiu en Botànica farmacèutica
Role of age and comorbidities in mortality of patients with infective endocarditis
[Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality.
[Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk.
[Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality.
[Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group
CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative
Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research
Sentinel-1&2 Multitemporal Water Surface Detection Accuracies, Evaluated at Regional and Reservoirs Level
Water stock monitoring is a major issue for society on a local and global scale. Sentinel-1&2 satellites provide frequent acquisitions to track water surface dynamics, proxy variables to enable water surface volume monitoring. How do we combine such observations along time for each sensor? What advantages and disadvantages of single-date, monthly or time-windowed estimations? In this context, we analysed the impact of merging information through different types and lengths of time-windows. Satellite observations were processed separately on optical (Sentinel-2) and radar (Sentinel-1) water detectors at 10 m resolution. The analysis has been applied at two scales. First, validating with 26 large scenes (110 × 110 km) in different climatic zones in France, time-windows yielded an improvement on radar detection (F1-score improved from 0.72 to 0.8 for 30 days on average logic) while optical performances remained stable (F1-score 0.89). Second, validating reservoir area estimations with 29 instrumented reservoirs (20–1250 ha), time-windows presented in all cases an improvement on both optical and radar error for any window length (5–30 days). The mean relative absolute error in optical area detection improved from 16.9% on single measurements to 12.9% using 15 days time-windows, and from 22.15% to 15.1% in radar detection). Regarding reservoir filling rates, we identified an increased negative bias for both sensors when the reservoir is nearly full. This work helped to compare accuracies of separate optical and radar capabilities, where optical statistically outperforms radar at both local and large scale to the detriment of less frequent measurements. Furthermore, we propose a geomorphological indicator of reservoirs to predict the quality of radar area monitoring (R2 = 0.58). In conclusion, we suggest the use of time-windows on operational water mapping or reservoir monitoring systems, using 10–20 days time-windows with average logic, providing more frequent and faster information to water managers in periods of crisis (e.g., water shortage) compared to monthly estimations
Optimal guidance for space applications
The first part of this study was focused on describe the state-of-art in optimization techniques for general space operations, and especially in landing operations. Numerous optimisation tools have been developed in the past years and may be profitably re-used in the frame of space operations. To take advantage of these developments, available software has to be compared, in terms of methods, performances and user-friendliness. Among the studied optimisation software, DIDO was selected for the second part of the study. In order to assess the performances of this Optimal Control Solver, tests have been performed on the asteroid landing scenario. Simulation results using the calculated optimal control profiles have shown the importance of the interpolation methods and the temporal resolution of the problem.Validerat; 20101217 (root
Subsample of the maximum Water Area Extent of Telangana Rainwater Harvesting System from Sentinel-2
<p>Small Reservoirs Maximum Water Area Extent polygones (MWAE) composing the Rainwater Harvesting System (RHS) derieved from Sentinel-2 Multispectral data in the Telangana state, South-India. MWAE is extracted from Sentinel-2 cloud free images time serie collected from 2016 to 2021 (last access in 2021) over the area covered by stereoscopic images acquired from Pléiades satellites (DEM available 10.5281/zenodo.10403040). A random forest classification is used with a set of training and validation samples. These samples are Sentinel pixel locations (10 x 10 meters) corresponding to permanent water pixels extracted from Global Surface Water datasets (doi:10.1038/nature20584) and never flooded pixels derived from Height Above Nearest Drainage data-set (10.1016/j.jhydrol.2011.03.051).</p>