Altimetry for the future: Building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Chemical and mineralogical patterns, and luminescence dating of miniature terracotta high-reliefs

Altos-relevos miniaturais em terracota policromada constituindo dois ciclos narrativos e pertencentes ao Museu Nacional de Arte Antiga (Lisboa) foram estudados. Pouco se sabe da sua autoria, contexto histórico-artístico e técnicas de produção. Perante a sua aparente semelhança formal e material, esta investigação procurou compreender as relações existentes entre estas obras em termos materiais, de fabrico e datação. A composição química dos corpos cerâmicos foi determinada pela análise por activação neutrónica e a composição mineral por difracção de raios X. Os aspectos cronológicos foram estudados por luminescência. Este estudo permitiu elucidar questões de cronologia, proveniência e de produção tecnológica quanto às matérias-primas e as temperaturas de cozedura usadas. Os resultados composicionais permitiram apontar para o recurso a matérias-primas distintas para os ciclos da Vida de São Francisco e da Paixão de Cristo e temperaturas de cozedura baixas. Os resultados de luminescência apontam para uma produção dos três altos-relevos analisados na segunda metade do século XVIII, em harmonia com os estudos de história de arte

Brass lamps: Preliminary study on the constituent materials and production technology by X-ray and microscopical techniques

This paper reports a preliminary study concerning two brass lamps belonging to the Évora Museum collection and one brass lamp belonging to a private collection. The main objective of this study was to acquire scientific data to assess the production technology used in the making of these lamps. Optical microscopy, X-ray digital radiography and scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) were used to study the base, oil reservoir and the reflector of the selected lamps. SEM/EDS analysis showed that although the analyzed parts of the lamps have slightly different elemental compositions, they are all made out of yellow brass (Cu 70% and Zn 30%, in w.t.) and soft-solder (Pb-Sn alloy). The lamp bases alloys also contain tin, which increases the dezincification resistance, and lead was also found in one of the lamps, which is known to increase malleability and reduce the melting point of the alloy. Metallographic procedures were performed on two selected components of a lamp. Observation of as-cast and wrought brass microstructures support the main processing techniques used in manufacturing of this kind of objects. Likewise, the metallic phase encountered – alpha – of the Cu-Zn binary system – are in agreement with the elemental analysis performed. This study reveals the importance of the radiography analysis to obtain a better understanding of structural aspects, as much thickness and density as mechanical processes and their impact on the manufacture of the different elements of these lamps. Fissures, cracks and restoration marks could also be identified in these lamps

Multianalytical approach for the authenticity of an eighteenth-century Pascal Taskin harpsichord

This paper surveys a detailed characterization of a prestigious harpsichord brought into fashion in 1782 by Pascal Taskin. The implemented analytical methodology required the use of in situ Energy Dispersive X-Ray Fluorescence (EDXRF) for elemental analysis of the color palette, optical and SEM imaging (SE and BSE modes) for the layered structure identification, Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) for elemental composition of the inorganic compounds, Fourier Transform Infrared (FTIR) spectroscopy for some binders and THM-GC/MS as well for resinous layers identification. By cross-checking these data with those obtained by digital radiography, it was concluded that a true ravalement of the harpsichord was in fact undertaken and that, among more than five interventions applied to the instrument until the present day, the third one may correspond to the one performed at Pascal Taskin’s time

Challenging wax-cast figurine serial production unravelled by multi-analytical techniques

Eight complementary techniques were successfully applied to study a pair of very alike eighteenth-century colored wax figurines belonging to the Museu Nacional Machado de Castro, Coimbra (Portugal): examination under visible and ultraviolet light, X-ray radiography (XRR), neutron radiography and tomography (NR and NT), energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), micro-X-ray diffraction (m-XRD), gas chromatography coupled with mass spectrometry (GC/MS) and micro-confocal Raman spectroscopy (m- Raman). A careful examination of the two objects provided an insight into their manufacturing and revealed that they were cast from the same molds, although details differ. The main cast material employed was a mixture of beeswax, Venice turpentine, other diterpenoid resins and a very low amount of lipids. The wax used was certainly reclaimed from a metallurgic activity involving lost-wax casting. Each figurine consists of sixteen parts, most of which consist of solid wax. The presence of fillings within the body was unexpected. The elements which remained hollowed played a fundamental role at the assembling stage. A loose wooden tenon helped to keep the head in place and metal rods were used to fasten the base to the main body. Polychromy was carried out in wax, with different pigments and opacifiers. The fabrication of the colored wax from different inorganic/organic wastes is also discussed. Textures were achieved by adding materials. The results gathered offered the unique opportunity to verify aspects inherent to the production of multiple copies in wax casting