Determination of a static gravimetric geoid for the Santa Fe province, Argentina

La determinación del geoide se ha convertido en la actualidad en uno de los objetivos fundamentales de la Geodesia, para dar lugar a una solución del problema altimétrico. Ésta problemática puede ser considerada en el contexto del modelado del campo de gravedad terrestre, ya que todos los métodos decálculo involucran de una u otra manera su conocimiento. El presente trabajo consiste en el cálculo de cuatro modelos de geoide gravimétrico estático para la provincia de Santa Fe (Argentina) y en su posterior validación con información terrestre de alturas elipsoidales (GNSS) y de Redes de Nivelación (RN). La metodología aplicada consistió en la técnica Remover-Restaurar, incorporando diversos Modelos de Geopotencial Global (MGG), junto con 39,771 observaciones gravimétricas terrestres. El cálculo de los modelos fue realizado con el paquete de programas canadiense SHGEO (Stokes-Helmert Geoid Software), desarrollado por el Departamento de Geodesia e Ingeniería Geomática de la Universidad de New Brunswick, Canadá. Los modelos de geopotencial global GO_CONS_GCF_2_DIR_R5 y EIGEN6C4, limitados hasta grado y orden 200 y 300, fueron utilizadoscomo referencia para el cálculo. Se utilizó además, el modelo digital de terreno SAM3s_v2 y el modelo de gravedad oceánica DTU10. El análisis estadístico se realizó con 100 puntos de doble información altimétrica (GNSS sobre nivelación), resultando el modelo calculado con base GO_CONS_GCF_2_DIR_R5 hasta grado y orden 300 el de mayor consistencia. El mismo fue el que presentó el mínimo valor medio de las alturas geoidales geométricas (NGNSS-RN) respecto a las obtenidas en el modelo calculado (N) (0.096m), y un RMS de dicha diferencia de 0.221 m.At present, the determination of the geoid has become one of the fundamental Geodesy objectives, in order to provide a solution for the altimetric problem. This can be considered in the context of the terrestrial gravity field modeling, since all the calculation methods involve in one way or another its knowledge. This work consists in the calculation of four static gravimetric geoid models for the province of Santa Fe (Argentina) and its validation with terrestrial information from ellipsoidal heights (GNSS) and Leveling Networks (RN). The applied methodology in this investigation was the Remove-Restore technique, and various Global Geopotential Models (MGG) along with 39,771 terrestrial gravimetric observations were incorporated in the study. The calculation of the models was accomplished with the Canadian SHGEO software package (Stokes-Helmert Geoid Software), developed by the Department of Geodesy and Geomatic Engineer of the University of New Brunswick, Canada. The global geopotential models GO_CONS_GCF_2_DIR_R5 and EIGEN6C4, limited to degree and order 200 and 300, were used as a reference for the calculation. Also, the SAM3s_v2 digital terrain model and the DTU10 oceanic gravity model were used. The statistical analysis was performed with 100 points with double altimetric information (GNSS on leveling), resulting the model based on the GO_CONS_GCF_2_DIR_R5 up to grade and order 300 the one with greater consistency. This model also presented the minimum geoidal height mean values (NGNSS-RN) with respect to those obtained in the calculated model (N) (0.096m), and an RMS of the difference of 0.221 m.Fil: Cornero, Cecilia. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Pereira, Ayelen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografia; ArgentinaFil: Varela, Mauricio Alejandro. Universidad de Costa Rica; Costa RicaFil: Oliveira Cancoro de Matos, Ana Cristina. Universidade de Sao Paulo; BrasilFil: Blitzkow, Denizar. Universidade de Sao Paulo; BrasilFil: Pacino, Maria Cristina. Universidad Nacional de Rosario. Facultad de Cs.exactas Ingeniería y Agrimensura. Escuela de Agrimensura. Departamento de Geotopocartografia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentin

Latin American registry of renal involvement in COVID-19 disease. The relevance of assessing proteinuria throughout the clinical course

The Latin American Society of Nephrology and Hypertension conducted a prospective cohort, multinational registry of Latin American patients with kidney impairment associated to COVID-19 infection with the objective to describe the characteristics of acute kidney disease under these circumstances. The study was carried out through open invitation in order to describe the characteristics of the disease in the region. Eight-hundred and seventy patients from 12 countries were included. Median age was 63 years (54–74), most of patients were male (68.4%) and with diverse comorbidities (87.2%). Acute kidney injury (AKI) was hospital-acquired in 64.7% and non-oliguric in 59.9%. Multiorgan dysfunction syndrome (MODS) due to COVID-19 and volume depletion were the main factors contributing to AKI (59.2% and 35.7% respectively). Kidney replacement therapy was started in 46.2%. Non-recovery of renal function was observed in 65.3%. 71.5% of patients were admitted to ICU and 72.2% underwent mechanical ventilation. Proteinuria at admission was present in 62.4% of patients and proteinuria during hospital-stay occurred in 37.5%. Those patients with proteinuria at admission had higher burden of comorbidities, higher baseline sCr, and MODS was severe. On the other hand, patients with de novo proteinuria had lower incidence of comorbidities and near normal sCr at admission, but showed adverse course of disease. COVID-19 MODS was the main cause of AKI in both groups. All-cause mortality of the general population was 57.4%, and it was associated to age, sepsis as cause of AKI, severity of condition at admission, oliguria, mechanical ventilation, non-recovery of renal function, in-hospital complications and hospital stay. In conclusion, our study contributes to a better knowledge of this condition and highlights the relevance of the detection of proteinuria throughout the clinical course

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E$^{-2}$ shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E$^{-2}$ be able to explain the observations

Extraction of the Muon Signals Recorded with the Surface Detector of the Pierre Auger Observatory Using Recurrent Neural Networks

We present a method based on the use of Recurrent Neural Networks to extract the muon component from the time traces registered with water-Cherenkov detector (WCD) stations of the Surface Detector of the Pierre Auger Observatory. The design of the WCDs does not allow to separate the contribution of muons to the time traces obtained from the WCDs from those of photons, electrons and positrons for all events. Separating the muon and electromagnetic components is crucial for the determination of the nature of the primary cosmic rays and properties of the hadronic interactions at ultra-high energies. We trained a neural network to extract the muon and the electromagnetic components from the WCD traces using a large set of simulated air showers, with around 450 000 simulated events. For training and evaluating the performance of the neural network, simulated events with energies between 1018.5, eV and 1020 eV and zenith angles below 60 degrees were used. We also study the performance of this method on experimental data of the Pierre Auger Observatory and show that our predicted muon lateral distributions agree with the parameterizations obtained by the AGASA collaboration