O ESTADO DA ARTE EM REFERENCIAIS GEODÉSICOS: ITRF2000 E AS PRÓXIMAS REALIZAÇÕES DO ITRS

In this paper is presented a brief historic of the ITRS realizations, giving details of the most recent, ITRF2000, as well as the parameters involved in the transformation among them. Some deficiencies of ITRF2000 are presented together with descriptions of how should be it in the future. Therefore, the status of Geodetic Reference System will be presented. Quality control analysis for some of the stations situated in the South American continent is presented in terms of precision and discrepancies with respect to other frames. Finally, it was emphasized about the care that one should take when using coordinates of stations located in regions subjected to seismic shock and earthquakes.Nesse artigo apresenta-se um breve histórico das realizações do ITRS, dando detalhes da mais recente, a ITRF2000, bem como os parâmetros envolvidos nas transformações entre elas. Apresentam-se algumas das deficiências da realização ITRF2000 e apontamentos de como deverão ser as novas realizações. Pretende-se com isso apresentar o estado da arte no que concerne aos referenciais Geodésicos. Análises de qualidade das coordenadas das estações pertencentes ao território Sul Americano também são apresentadas, quer seja em termos de precisão, como no que concerne às discrepâncias em relação a outras realizações. Finalmente, discute-se sobre os cuidados que devem ser tomados ao utilizar as coordenadas de estações localizadas em regiões onde ocorrem abalos sísmicos e terremotos

Status of the SIRGAS reference frame: recent developments and new challenges

In accordance with recent developments of the International Association of Geodesy (IAG) and the policies promoted by the Subcommittee on Geodesy of the United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM), a main goal of the Geodetic Reference System for the Americas (SIRGAS) is the procurement of an integrated regional reference frame. This frame should support the precise determination of geocentric coordinates and also provide a unified physical reference frame for gravimetry, physical heights, and a geoid. The geometric reference frame is determined by a network of about 500 continuously operating GNSS stations, which are routinely processed by ten analysis centers. The GNSS solutions from the analysis centers are used to generate weekly station positions aligned to the International Terrestrial Reference Frame (ITRF) and multi-year (cumulative) reference frame solutions. This processing is also the basis for the generation of precise tropospheric zenith path delays with an hourly sampling rate over the Americas. The reference frame for the determination of physical heights is a regional densification of the International Height Reference Frame (IHRF). Current efforts focus on the estimation and evaluation of potential values obtained from high resolution gravity field modelling, an activity tightly coupled with geoid determination. The gravity reference frame aims to be a regional densification of the International Terrestrial Gravity Reference Frame (ITGRF). Thus, SIRGAS activities are focused on evaluating the quality of existing absolute gravity stations and to identify regional gaps where additional absolute gravity stations are needed. Another main goal of SIRGAS is to promote the use of its geodetic reference frame at the national level and to support capacity building activities in the region. This paper summarizes key milestones in the establishment and maintenance of the SIRGAS reference frame and discusses current efforts and future challenges.Fil: Alves Costa, Sonia M.. Instituto Brasileiro de Geografia E Estatística; BrasilFil: Sanchez, Laura. Technische Universität München; AlemaniaFil: Piñon, Diego. Ministerio de Defensa. Instituto Geografico Nacional; ArgentinaFil: Tarrio Mosquera, Jose A.. Universidad de Santiago de Chile; ChileFil: Guimaraes, Gabriel. Universidade Federal de Uberlandia; BrasilFil: Demian Gomez. Ohio University; Estados UnidosFil: Drewes, Hermann. Deutsches Geodätisches Forschungsinstitut; AlemaniaFil: Mackern Oberti, María Virginia. Universidad Nacional de Cuyo. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Antokoletz, Ezequiel Darío. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: de Matos, Ana C. O.C. Universidade de Sao Paulo; BrasilFil: Blitzkow, Denizar. Universidade de Sao Paulo; Brasi

SIRGAS: the core geodetic infrastructure in Latin America and the Caribbean

COMUNICACIÓN CIENTÍFICA PRESENTADA EN ASAMBLEA CIENTÍFICA CONJUNTA DE LA ASOCIACIÓN INTERNACIONAL DE GEODESIA Y LA ASOCIACIÓN INTERNACIONAL DE SISMOLOGÍA Y FÍSICA DEL INTERIOR DE LA TIERRA (IAG-IASPEI 2017), 30 de julio - 4 de agosto de 2017, Kobe, Japón. SIRGAS reference frame The primary objective of SIRGAS (Sistema de eferencia Geocéntrico para las Américas) is the determination and maintenance of a reliable reference frame in Latin America and the Caribbean as a densification of the ITRF and as a regional realisation of the ITRS. The SIRGAS reference frame is currently composed of 418 continuously operating GNSS stations (Fig. 1). It comprises two hierarchy levels: a core network (SIRGAS-C) providing the primary link to the global ITRF; and national reference networks (SIRGAS-N) improving the geographical density of the reference stations to ensure the accessibility to the reference frame at national and local levels. Given that most of the existing ITRF stations in South America are affected by the strong seismic activity in this region, further stations located in Europe, Africa, Oceania and North America are included in SIRGAS to increase the availability of fiducial point

The Vertical Reference System in the Argentine Republic

This paper is a summary of the tasks that have been developed and the ones that are under development in the Argentine Republic by means of joint activities, agreements and cooperation among institutions, together with national and international scientific and educational agencies, related to: -Completion, calculation, unification and link to planialtimetric networks. -Gravity activities and procedures used for heights correction. -Linking to neighboring countries networks. -Initial leveling experiences by means of GPS technology, and results obtained. -Regional and national geoid modeling. -Determination of vertical crustal movements, evaluation of sea technology, variations of the mean sea level and its influence over the zero of the argentine height system.Facultad de Ciencias Astronómicas y Geofísica

Building research initiative group: chronic illness management and adherence in transplantation (BRIGHT) study: study protocol

Protocol[Abstract] AIM: This article describes the rationale, design and methodology of the Building research initiative group: chronic illness management and adherence in transplantation (BRIGHT) study. This study of heart transplant patients will: (1) describe practice patterns relating to chronic illness management; (2) assess prevalence and variability of non-adherence to the treatment regimen; (3) determine the multi-level factors related to immunosuppressive medication non-adherence. BACKGROUND: The unaltered long-term prognosis after heart transplantation underscores an urgent need to identify and improve factors related to survival outcomes. The healthcare system (e.g. level of chronic illness management implemented) and patient self-management are major drivers of outcome improvement. DESIGN: The study uses a survey design in 40 heart transplant centres covering 11 countries in four continents. METHODS: Theoretical frameworks informed variable selection, which are measured by established and investigator-developed instruments. Heart transplant recipients, outpatient clinicians and programme's directors complete a survey. A staged convenience sampling strategy is implemented in heart transplant centres, countries and continents. Depending on the centre's size, a random sample of 25-60 patients is selected (N estimated 1680 heart transplant recipients). Five randomly selected clinicians and the medical director from each centre will be invited to participate. CONCLUSION: This is the first multi-centre, multi-continental study examining healthcare system and heart transplant centres chronic illness management practice patterns and potential correlates of immunosuppressive medication non-adherence. The knowledge gained will inform clinicians, researchers and healthcare policy makers at which level(s) interventions need to be implemented to improve long-term outcomes for transplant recipient