6 research outputs found
Evaluation of Near-Surface Air Temperature from Reanalysis over the United States and Ukraine: Application to Winter Wheat Yield Forecasting
In this work we evaluate the near-surface air temperature datasets from the ERA-Interim, JRA55, MERRA2, NCEP1, and NCEP2 reanalysis projects. Reanalysis data were first compared to observations from weather stations located on wheat areas of the United States and Ukraine, and then evaluated in the context of a winter wheat yield forecast model. Results from the comparison with weather station data showed that all datasets performed well (r2>0.95) and that more modern reanalysis such as ERAI had lower errors (RMSD ~ 0.9) than the older, lower resolution datasets like NCEP1 (RMSD ~ 2.4). We also analyze the impact of using surface air temperature data from different reanalysis products on the estimations made by a winter wheat yield forecast model. The forecast model uses information of the accumulated Growing Degree Day (GDD) during the growing season to estimate the peak NDVI signal. When the temperature data from the different reanalysis projects were used in the yield model to compute the accumulated GDD and forecast the winter wheat yield, the results showed smaller variations between obtained values, with differences in yield forecast error of around 2% in the most extreme case. These results suggest that the impact of temperature discrepancies between datasets in the yield forecast model get diminished as the values are accumulated through the growing season
Spectral and Atmospheric Characterization of a Site at Atacama Desert for Earth Observation Sensor Calibration
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Previous issue date: 2015Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fondecyt-Initial (CONICYT) [11130359]The application of Earth observation sensor data in quantitative approaches calls on the conversion of original digital numbers to radiometric quantities such as radiance or reflectance. This conversion depends on the sensor absolute calibration. One of the postlaunch methods adopted to calibrate orbital sensors is the reflectance-based approach. According to this method, a reference surface with specifics characteristics is required. The main objective of this work is to evaluate the suitability of a specific surface located at Atacama Desert in Chile to be used as a reference surface for calibration of Earth observation sensor purposes. A field campaign was carried out from August 19 to 22, 2014, when radiometric measurements were performed to spectrally characterize the reference surface and to evaluate the atmospheric characteristics of the study area. The average reference surface reflectance factor in the spectral region from 350 to 2500 nm ranged from 0.1 to 0.3, and its spatial uniformity was within 2%-4%. The amount of atmospheric aerosols was low, with an aerosol optical depth at 550 nm between 0.08 and 0.11 during the fieldwork period. The climate is hyperarid, and the water column abundance was lower than 0.43 g/cm(2). The results demonstrated that a reference surface at Atacama Desert could be effectively used for calibration of either airborne or orbital electrooptical sensors, providing an excellent surface in South America.[Pinto, Cibele T.; Ponzoni, Flavio J.] Natl Inst Space Res INPE, Div Remote Sensing, Sao Jose Dos Campos, Brazil[Barrientos, C.] Chile Air Force, Aerial Photogrammetr Serv, Santiago, Chile[Mattar, C.; Santamaria-Artigas, A.] Univ Chile, Dept Environm Sci & Renewable Nat Resources, Lab Anal Biosphere, Santiago 1058, Chile[Castro, Ruy M.] Inst Adv Studies IEAv CTA, Div Geointelligence EGI, BR-12231970 Sao Jose Dos Campos, Brazil[Castro, Ruy M.] Universidade de Taubaté (Unitau) , Div Math & Phys, BR-12201970 Taubate, Brazi
The ARYA crop yield forecasting algorithm: Application to the main wheat exporting countries
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Can nebulised HepArin Reduce morTality and time to Extubation in patients with COVID-19 Requiring invasive ventilation Meta-Trial (CHARTER-MT): protocol and statistical analysis plan for an investigator-initiated international meta-trial of prospective randomised clinical studies
There is significant interest in the potential for nebulised unfractionated heparin (UFH), as a novel therapy for patients with COVID-19 induced acute hypoxaemic respiratory failure requiring invasive ventilation. The scientific and biological rationale for nebulised heparin stems from the evidence for extensive activation of coagulation resulting in pulmonary microvascular thrombosis in COVID-19 pneumonia. Nebulised delivery of heparin to the lung may limit alveolar fibrin deposition and thereby limit progression of lung injury. Importantly, laboratory studies show that heparin can directly inactivate the SARS-CoV-2 virus, thereby prevent its entry into and infection of mammalian cells. UFH has additional anti-inflammatory and mucolytic properties that may be useful in this context. METHODS AND INTERVENTION: The Can nebulised HepArin Reduce morTality and time to Extubation in Patients with COVID-19 Requiring invasive ventilation Meta-Trial (CHARTER-MT) is a collaborative prospective individual patient data analysis of on-going randomised controlled clinical trials across several countries in five continents, examining the effects of inhaled heparin in patients with COVID-19 requiring invasive ventilation on various endpoints. Each constituent study will randomise patients with COVID-19 induced respiratory failure requiring invasive ventilation. Patients are randomised to receive nebulised heparin or standard care (open label studies) or placebo (blinded placebo-controlled studies) while under invasive ventilation. Each participating study collect a pre-defined minimum dataset. The primary outcome for the meta-trial is the number of ventilator-free days up to day 28 day, defined as days alive and free from invasive ventilation
Can nebulised HepArin Reduce morTality and time to Extubation in patients with COVID-19 Requiring invasive ventilation Meta-Trial (CHARTER-MT) : Protocol and statistical analysis plan for an investigator-initiated international meta-trial of prospective randomised clinical studies
There is significant interest in the potential for nebulised unfractionated heparin (UFH), as a novel therapy for patients with COVID-19 induced acute hypoxaemic respiratory failure requiring invasive ventilation. The scientific and biological rationale for nebulised heparin stems from the evidence for extensive activation of coagulation resulting in pulmonary microvascular thrombosis in COVID-19 pneumonia. Nebulised delivery of heparin to the lung may limit alveolar fibrin deposition and thereby limit progression of lung injury. Importantly, laboratory studies show that heparin can directly inactivate the SARS-CoV-2 virus, thereby prevent its entry into and infection of mammalian cells. UFH has additional anti-inflammatory and mucolytic properties that may be useful in this context. Methods and intervention: The Can nebulised HepArin Reduce morTality and time to Extubation in Patients with COVID-19 Requiring invasive ventilation Meta-Trial (CHARTER-MT) is a collaborative prospective individual patient data analysis of on-going randomised controlled clinical trials across several countries in five continents, examining the effects of inhaled heparin in patients with COVID-19 requiring invasive ventilation on various endpoints. Each constituent study will randomise patients with COVID-19 induced respiratory failure requiring invasive ventilation. Patients are randomised to receive nebulised heparin or standard care (open label studies) or placebo (blinded placebo-controlled studies) while under invasive ventilation. Each participating study collect a pre-defined minimum dataset. The primary outcome for the meta-trial is the number of ventilator-free days up to day 28 day, defined as days alive and free from invasive ventilation