Instrumental response of scintrex autograv cg-5 (s/n 40484) gravity meter in continuous and survey modes

Debido a sus características técnicas y su simplicidad de medición, el gravímetro automático Scintrex CG-5 es usado por una variada gama de usuarios. Diversas investigaciones han demostrado que el desempeño de cada gravímetro debe ser evaluado particularmente, puesto que la respuesta de cada instrumento es afectada de forma diferente por factores externos, dando lugar a residuos que podrían ser del orden de la precisión demandada. En este trabajo, para el gravímetro Scintrex CG-5 S/N 40484: 1) Se investigó en condiciones de laboratorio para el modo continuo, la influencia sobre los registros gravimétricos de variables meteorológicas (presión y temperatura atmosféricas). También se determinó la deriva instrumental de largo plazo (registros de 35 días). 2) En el modo relevamiento se llevó a cabo una calibración, una determinación de gradiente vertical de gravedad local y mediciones sobre puntos situados en la provincia de San Juan. Las diferencias de gravedad entre estaciones y los parámetros del gravímetro fueron estimadas mediante un ajuste de red. En base a nuestros resultados, concluimos que este instrumento podría detectar en modo continuo (e.g., movilidad cortical, hidrogeología, etc.) o en modo relevamiento, variaciones de gravedad con exactitudes de algunos microgales. En ambos casos es necesario seguir un adecuado protocolo de medición y postprocesamiento de datos.Due to its technical characteristics and simplicity of measurement, the automatic gravimeter Scintrex CG-5 is used by a wide range of users. Several investigations have shown that the performance of each gravimeter must be assessed in particular, since the response of each instrument is affected differently by external factors, giving rise to residuals that could be of the order of the demanded accuracy. In this work, for the gravimeter Scintrex CG-5 S/N 40484: 1) It was investigated under laboratory conditions for the continuous mode, the influence on gravimetric records of meteorological variables (atmospheric pressure and temperature). The long term instrumental drift (35 days records) was also determined. 2) In survey mode was carried out a calibration, a determination of vertical gradient of local gravity, and measurements on points located in the province of San Juan. Gravity differences between stations and the gravimeter parameters were estimated by means of a network adjustment. Based on our results, we conclude that this instrument could detect in continuous mode (e.g., crustal movements, hydrogeology, etc.) or in survey mode, variations of gravity with accuracies of some microgals. In both cases it is necessary to follow a proper measurement protocol and post-processing of data.Fil: Miranda, Silvia Alicia. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Herrada, Alfredo. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Pacino, Maria Cristina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Fractalness of land gravity data and residual isostatic anomalies map of Argentina, Chile and western Uruguay

Gravity anomalies are often strongly influenced by topography, which effect is mitigated through appropriate reductions. Usually, a standard value of 2670 kg/m3 is used for the density of topography in the absence of specific information. However, various methods have been implemented to obtain density of topography estimates directly from the gravity data. A particularly suitable technique for regional scale studies is based on analyzing the fractal nature of gravity anomalies for a particular region. In this paper the fractalness of the onshore gravity anomalies for Argentina, Chile and part of Uruguay is analyzed by using an updated gravity database. The fractal dimensions of the topography and gravity anomaly data were estimated by means of the variogram technique in the spatial domain. As a result of this analysis, it was found that the optimum density for the studied region has a value of 2300 kg/m3. This density was used to prepare a map of isostatic residual anomalies using the Airy-Heiskanen model. The main anomalies recognized on this map were interpreted in relation to the degree of isostatic balance and the densities of rocks near to the surface.Las anomalías de gravedad suelen estar fuertemente influenciadas por la topografía, cuyo efecto es atenuado a través de adecuadas reducciones. Usualmente, ante la falta de información específica, se usa un valor estándar de 2670 kg/m3 para la densidad de la topografía por encima del geoide. Hasta el presente varios métodos han sido implementados para obtener estimaciones de dicha densidad directamente a partir de los datos de gravedad mismos. Una técnica especialmente conveniente para estudios de carácter regional se basa en analizar la naturaleza fractal de las anomalías de gravedad para una región en particular. En este trabajo se analiza la fractalidad de las anomalías de gravedad para Argentina, Chile y parte de Uruguay continentales utilizando una base de datos de gravedad actualizada. Se estimó la dimensión fractal D de los datos topográficos y de anomalías de gravedad por medio de la técnica de variograma en el dominio espacial. Como resultado de este análisis se encontró que la densidad óptima para esta región tiene un valor de 2300 kg/m3. Esta densidad se usó para preparar un mapa de anomalías residuales isostáticas en el sistema de Airy-Heiskanen. Las principales anomalías reconocidas en este mapa se interpretaron con relación al grado de balance isostático y a las densidades de las rocas cercanas a la superficie.Fil: Miranda, Silvia Esther. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Herrada, Alfredo Héctor. Universidad Nacional de San Juan; ArgentinaFil: Pacino, Maria Cristina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Student Response Systems: A Multidisciplinary Analysis Using Visual Analytics

In recent years, several innovations have emerged in the field of education, including Blended-Learning, Massive Open Online Courses, Flipped Classroom and Gamification. In particular, several investigations have highlighted the effectiveness of student response systems, or clickers, in different subjects and disciplines. Although some literature reviews have been published on this subject, none of them offer a review of a large volume of publications from a multidisciplinary approach. Similarly, in the literature there are no studies that have analyzed scientific collaborations on this subject. To respond to these concerns, we proposed the use of a bot to retrieve information from a large number of papers (1696 documents co-authored by a total of 4091 researchers) included in the Scopus database. The disciplines covered include natural sciences, engineering and technology, medical and health sciences, agricultural and veterinary sciences, social sciences and humanities, and the arts. The review of the literature reveals that student response systems are generally well-perceived by teachers and students in all the disciplines. Another interesting result achieved from visual data obtained using network visualization software and word clouds is that student response systems are mainly used in some disciplines, such as physics, chemistry, medicine, and nursing. It is clearly observed that the relationship between researchers from the same country is stronger than between researchers from different countries. Finally, some reflections are included on the role of student response systems in online teaching, especially regarding the changes experienced after the COVID-19 pandemic

Monitoreo de la calidad de datos GPS continuo: la Estación UNSJ (San Juan, Argentina)

Como parte de la red de referencia de operación continua de Argentina, la estación GPS (Global Positioning System) denominada UNSJ (Universidad Nacional de San Juan) fue establecida en la ciudad de San Juan el 6 de Marzo de 2007. Los datos registrados de UNSJ son ampliamente utilizados en aplicaciones catastrales, y sirven como base para la definición de los marcos de referencia geodésicos nacional y regional. Como una componente fundamental de la infraestructura geodésica, resulta conveniente un eficiente control de calidad de los datos crudos y el monitoreo de la estabilidad de una estación GPS de referencia. En este trabajo se presentan los resultados del control de calidad de las observaciones UNSJ luego de dos años de operación. Para controjar y caracterizar el desempeño del receptor GPS y además el medio ambiente de la estación, se eligieron cuatro índices. Ellos son el número de observaciones, multicamino en Ll, multicamino en L2 y ocurrencia de saltos de ciclos. También, se evaluó la estabilidad de largo término de la estación UNSJ a través del análisis de las series temporales de las coordenadas semanales provistas por los centros de cálculo SIRGAS (Sistema de Referencia Geocéntrico para las Américas). Completa este estudio el análisis de las coordenadas calculadas por distintos servicios de procesamiento disponibles en Internet. Nuestros resultados indican que durante el período analizado, el funcionamiento de la estación UNSJ fue satisfactorio, produciendo índices de calidad que son aceptables para estándares internacionales.As a part of the Argentine continuously operating reference station network, a GPS (Global Positioning System) station named UNSJ (Universidad Nacional de San Juan) was established in San Juan city on 6th March 2007. The recorded data of UNSJ are widely applied to cadastral surveys and serve as the basis for defining national and regional geodetic reference frames. As a key component of the geodetic infrastructure, an efficient quality control of raw data and stability monitoring of a GPS reference station is highly convenient. In this study, results of quality control of the UNSJ observations after two year of operation are reported. In order to check and characterize the receiver performance and the station environment, four indices were chosen. They are the number of observations, multipath on Ll, multipath on L2 and cycle slips occurrence. Also, the long term stability of UNSJ station was evaluated through the analysis of weekly coordinate time series provided by the SIRGAS (Geocentric Reference System for the Americas) calculus centers. The analysis of the coordinates derived from different online processing services completes this study. The results indicate that during the analyzed period, the functioning of the station UNSJ was satisfactory, producing qualit indexes that are acceptable to international standards.Asociación Argentina de Geofísicos y Geodesta

Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

Protocols and formats for the dissemination of GNSS data (global navigation satellite system): a review

El Instituto Geográfico Nacional de Argentina (IGN), en concordancia con la tendencia internacional y conjuntamente con diversas instituciones públicas nacionales, generó en el año 1998 un proyecto consistente en la instalación de estaciones GPS/GNSS (Global Positioning System/Global Navigation Satellite System) permanentes en el territorio nacional. En la actualidad, la Red Argentina de Monitoreo Satelital Continuo (RAMSAC) está conformada por 64 Estaciones Continuas GNSS (EC) que materializan el Marco de Referencia Geodésico ITRF-2005 (Época 2006, 632). El desarrollo sostenido y la confiabilidad de la red RAMSAC, junto con la evolución de las aplicaciones y posibilidades asociadas a internet, particularmente las técnicas de transmisión de datos a través del protocolo IP (Internet Protocol) mediante la división de datos en tamaños apropiados, han posibilitado la implementación de un sistema de correcciones en tiempo real basado en los datos provistos por las Estaciones (EC). La metodología aplicada, se basa en el desarrollo elaborado por la Agencia Federal de Cartografía y Geodesia de la República Federal de Alemania (Federal Agency for Cartography and Geodesy, BKG), difundida bajo la denominación de Networked Transport of RTCM via Internet Protocol (NTRIP), que permite la obtención en tiempo real de coordenadas (latitud, longitud y altura) a múltiples usuarios con niveles de precisión sub-métrica. Este artículo sintetiza los diversos modos de entrega de datos GNSS en tiempo real, en términos de protocolos de transmisión, formatos de datos, vínculos de comunicación, estructura de mensajes y contenidos entre las diversas versiones de formatos RTCM SC-104 (Radio Technical Commission for Maritime Services- Special Committee 104), incluyendo enmiendas recientes.In 1998, in line with the international trend, the National Geographic Institute of Argentina (IGN) in partnership with various national public institutions initiated a project for the installation of a series of GPS/GNSS (Global Positioning System/Global Navigation Satellite System) permanent stations across their national territory. At the present time, this Argentine Network of Continuous Satellite Monitoring (RAMSAC) is composed of 64 Continuous Stations (EC) that materialize the Geodetic Reference Frame ITRF-2005 (Epoch 2006.632). The sustainable development and the reliability of this RAMSAC network, along with the evolution of applications and possibilities associated with the Internet (particularly the techniques of data transmission via the Internet Protocol through the division of data into appropriate sizes) have enabled the implementation of a real-time correction system based on the data provided by these Continuous Stations. The methodology applied is based on the development elaborated by the Federal Agency for Cartography and Geodesy of the Federal Republic of Germany (BKG) broadcast under the name Networked Transport of RTCM via Internet Protocol (NTRIP). It allows multiple users to obtain, in real-time, coordinates (latitude, longitude and height) with sub-meter accuracy levels. This article summarizes the various modes of real-time GNSS data delivery in terms of transmission protocols, data formats, links of communication, structure of messages, and content between different versions of the RTCM SC-104 formats (Radio Technical Commission for Maritime Services - Special Committee 104), including recent amendments.Asociación Argentina de Geofísicos y Geodesta

Student Response Systems: A Multidisciplinary Analysis Using Visual Analytics

In recent years, several innovations have emerged in the field of education, including Blended-Learning, Massive Open Online Courses, Flipped Classroom and Gamification. In particular, several investigations have highlighted the effectiveness of student response systems, or clickers, in different subjects and disciplines. Although some literature reviews have been published on this subject, none of them offer a review of a large volume of publications from a multidisciplinary approach. Similarly, in the literature there are no studies that have analyzed scientific collaborations on this subject. To respond to these concerns, we proposed the use of a bot to retrieve information from a large number of papers (1696 documents co-authored by a total of 4091 researchers) included in the Scopus database. The disciplines covered include natural sciences, engineering and technology, medical and health sciences, agricultural and veterinary sciences, social sciences and humanities, and the arts. The review of the literature reveals that student response systems are generally well-perceived by teachers and students in all the disciplines. Another interesting result achieved from visual data obtained using network visualization software and word clouds is that student response systems are mainly used in some disciplines, such as physics, chemistry, medicine, and nursing. It is clearly observed that the relationship between researchers from the same country is stronger than between researchers from different countries. Finally, some reflections are included on the role of student response systems in online teaching, especially regarding the changes experienced after the COVID-19 pandemic