First spaceborne observation of sea surface height using GPS-reflectometry

An analysis of spaceborne Global Positioning System reflectometry (GPS-R) data from the TechDemoSat-1 (TDS-1) satellite is carried out to image the ocean sea surface height (SSH). An SSH estimation algorithm is applied to GPS-R delay waveforms over two regions in the South Atlantic and the North Pacific. Estimates made from TDS-1 overpasses during a 6 month period are aggregated to produce SSH maps of the two regions. The maps generally agree with the global DTU10 mean sea surface height. The GPS-R instrument is designed to make bistatic measurements of radar cross section for ocean wind observations, and its altimetric performance is not optimized. The differences observed between measured and DTU10 SSH can be attributed to limitations with the GPS-R instrument and the lack of precision orbit determination by the TDS-1 platform. These results represent the first observations of SSH by a spaceborne GPS-R instrument

Living with chronic migraine: a qualitative study on female patients' perspectives from a specialised headache clinic in Spain

OBJECTIVES: The aim of this study was to explore the views and experiences of a group of Spanish women suffering from chronic migraine (CM). SETTING: Headache clinic at a university hospital in Madrid (Spain). PARTICIPANTS: Purposeful sampling of patients that attended a specialised headache clinic for the first time between June 2016 and February 2017 was performed. The patients included were females aged 18–65 and with positive diagnoses of CM according to the International Classification of Headache disorders (third edition, beta version), with or without medication overuse. Accordingly, 20 patients participated in the study with a mean age of 38.65 years (SD 13.85). DESIGN: Qualitative phenomenological study. METHODS: Data were collected through in-depth interviews, researchers’ field notes and patients’ drawings. A thematic analysis was performed following appropriate guidelines for qualitative research. RESULTS: Five main themes describing the significance of suffering emerged: (a) the shame of suffering from an invisible condition; (b) treatment: between need, scepticism and fear; (c) looking for physicians’ support and sincerity and fighting misconceptions; (d) limiting the impact on daily life through self-control; and (e) family and work: between understanding and disbelief. The disease is experienced as an invisible process, and the journey to diagnosis can be a long and tortuous one. Drug prescription by the physician is greeted with distrust and scepticism. Patients expect sincerity, support and the involvement of their doctors in relation to their disease. Pain becomes the main focus of the patient’s life, and it requires considerable self-control. The disease has a strong impact in the work and family environment, where the patient may feel misunderstood. CONCLUSIONS: Qualitative research offers insight into the way patients with CM experience their disease and it may be helpful in establishing a more fruitful relationship with these patients

A pre-correlation RFI mitigation algorithm for L-band interferometric radiometers

Radio Frequency Interference (RFI) is a major concern for both real and synthetic aperture radiometers. After the lessons learnt from SMOS, ESA is preparing the next generation of L-band interferometric radiometers with RFI mitigation integrated into the cross-correlators. This work presents a preliminary design and results of a pre-correlation RFI mitigation algorithm tailored for interferometric radiometers. The results show that the correlation error introduced by the RFI is reduced on average to the half, with peaks of 20 dB of mitigation.Peer ReviewedPostprint (author's final draft

RFI detection and mitigation for advanced correlators in interferometric radiometers

This work presents the first RFI detection and mitigation algorithm for the interferometric radiometers that will be implemented in its correlator unit. The algorithm operates in the time and frequency domains, applying polarimetric and statistical tests in both domains, and exhibiting a tunable and arbitrary low probability of false alarm. It is scalable to a configurable number of receivers, and it is optimized in terms of quantization bits and the implementation of the cross-correlations in the time or frequency domains for hardware resource saving. New features of this algorithm are the computation of the Stokes parameters per frequency bin in the Short-Time Fourier Transform and a new parameter called Polarimetric Kurtosis. If RFI is detected in one domain or in both, it is removed using the calculated blanking masks. The optimum algorithm parameters are computed, such as length of the FFTs, the threshold selection for a given probability of false alarm, and the selection of the blanking masks. Last, an important result refers to the application of Parseval’s theorem for the computation of the cross-correlations in the frequency domain, instead of in the time domain, which is more efficient and leads to smaller errors even when using moderate quantization levels. The algorithm has been developed in the framework of the ESA’s technology preparation for a potential L-band radiometer mission beyond SMOS. However, it is also applicable to (polarimetric) real aperture radiometers, and its performance would improve if more than one bit is used in the signal quantization.This research was funded by ESA, grant number ITT AO9359, by project SPOT: Sensing with Pioneering Opportunistic Techniques grant RTI2018-099008-B-C21/AEI/10.13039/501100011033, and the grant for recruitment of early stage research staff of the Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR) Generalitat de Catalunya, Spain (FISDUR2020/105).Peer ReviewedPostprint (published version

Tsunami detection using the PARIS concept

Abstract On 26 December 2004 a tsunami generated by an earthquake with its epicentre in the Indian Ocean West of Indonesia caused a real human and material catastrophe in the region. After the event some proposals to establish a network of sensors for tsunami detection were put forward. This paper presents an alternative concept that can be applied from satellite, aircraft or from the coast, and which can complement such a network of sensors for fast tsunami detection. The concept makes use of GNSS signals reflected from the ocean's surface to perform mesoscale ocean altimetry. The technique, designated PARIS (Passive Reflectometry and Interferometry System), aims at capturing fast topographic events happening on the ocean surface such as eddies and fronts. The paper includes details of some aircraft experiments whereby a PARIS altimeter was used to map a topographic signature with amplitude and wavelength similar to a tsunami in open ocean

Sistemática y filogenia de briofitas y plantas vasculares sin semilla en el cono sur

Este proyecto propone el estudio sistemático y filogenético de las briofitas (Bryophyta,Marchantiophyta y Anthocerotophyta) y helechos (Clase Polypodiopsidae) en el Cono Sur. En relación a las briofitas, durante el último siglo se describieron numerosas especies para el área, sin embargo de muchas de ellas se desconoce su situación taxonómica real ya que no fueron revisadas posteriormente. En el caso de los helechos, el conocimiento de su diversidad y estado taxonómico es mayor, sin embargo durante los últimos 30 años los estudios moleculares han revolucionado enteramente la circunscripción de los grupos en búsqueda de la monofilia de los mismos y actualmente la mayoría de ellos no se encuentran totalmente resueltos. En vista de esta situación, en este proyecto nos propusimos inventariar, monitorear e identificar briófitas y helechos en el contexto de tipos de vegetación en el Cono Sur que propendan al conocimiento de la riqueza de especies. Para cumplir con estos objetivos se efectúan relevamientos florísticos en áreas escasamente inventariadas con énfasis en el NOA y NEA. Los especímenes se estudian en base a la metodología clásica para estos organismos; la identificación se realiza por medio de los ?tipos históricos? solicitados en calidad de préstamo a instituciones nacionales e internacionales. Como resultados del primer año de funcionamiento del proyecto, se ha incrementado el número de especímenes briológicos y pteridológicos que forman parte del herbario LIL, que permiten mantener un canje activo con instituciones internacionales. Para briofitas se realizaron estudios y descripciones morfo-anatómicas de especies nuevas para el área de estudio, así como nuevas para la ciencia: Mitthenothamnium reduncum (Schimp. ex Mitt.) Ochyra, Asterella chilensis (Nees & Mont.) A. Evans, Pleuridium tucumanensis M. T. Colotti, G. M. Suárez y D. F. Peralta sp. nov., Symphyogyna brasiliensis Nees, Syzygiella teres (Carrington & Pearson) Váña y Fissidens submarginatus Bruch., entre otras. A su vez, se realizaron actualizaciones nomenclaturales, efectuando revisiones a nivel de familia y género. Se contribuyó con estudios filogenéticos para evaluar la monofilia de grupos conflictivos mediante datos morfológicos y moleculares. Para helechos, se llevaron a cabo descripciones morfo-anatómica para la identificación de especies nativas del Cono Sur: Doryopteris triphylla (Lam.) Christ, Pleopeltis macrocarpa (Bory ex. Willd) Kaulf, Notholaena sulphurea (Cav.) Sm., entre otras. Se investigaron las secreciones vegetales de dichas especies, destacando su potencial uso en el campo agronómicomedicinal. Tanto para musgos como para helechos se realizaron trabajos de divulgación científica destinados a comunidades científicas no afines a la botánica y población en general no afín a la ciencia. Cabe destacar también, el desarrollo en curso de material didáctico estudiantil y docente de nivel medio en escuelas universitarias.Fil: Suarez, Guillermo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Colotti, M. T.. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Neira, Diego Amando. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Flores, J. R.. University of Helsinki; FinlandiaFil: Jimenez, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Cabral, R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Hernández, Micaela Anahí. Fundación Miguel Lillo. Dirección de Botánica; ArgentinaFil: Jimenez, L. I.. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Catalano, Santiago Andres. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaXIV Jornadas Internas de Comunicaciones en Investigación, Docencia y ExtensiónSan Miguel de TucumánArgentinaUniversidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lill