A precise 90º quadrature OTA-C oscillator tunable in the 50-130-MHz range

We present a very-large-scale integration continuous-time sinusoidal operational transconductance amplifiers quadrature oscillator fabricated in a standard double-poly 0.8-μm CMOS process. The oscillator is tunable in the frequency range from 50 to 130 MHz. The two phases produced by the oscillator show a low-quadrature phase error. A novel current-mode amplitude control scheme is developed that allows for very small amplitudes. Stability of the amplitude control loop is studied as well as design considerations for its optimization. Experimental results are provided

Sensor de humedad del suelo de bajo coste para control de regadíos

This paper presents a low-cost system to measure soil humidity for application in irrigation control. It is based in the simultaneous measurement of the real and imaginary parts of the impedance of a volume of soil comprised between two conducting electrodes. The separation of real and imaginary parts allows for an accurate measurement of water contents even in soils with high salinity. An ASIC is being developed which acts as interface between a capacitive probe and a microcontroller. Satisfactory laboratory tests have been completed on a first prototype. The system will be used to reduce the water consumption in agriculture by determining the optimum volume of water to use.Se presenta un sistema de medida de humedad del suelo para aplicaciones en el control de riegos. Basado en la medida de las componentes real e imaginaria de la impedancia presentada por el volumen de suelo comprendido entre dos electrodos, permite determinar de forma fiable el contenido de humedad incluso en suelos salinos. Se está desarrollando un ASIC que actúa como interfase entre una sonda capacitiva y un microcontrolador y se han completado las pruebas de laboratorio sobre un primer prototipo. El sistema será empleado como medidor de humedad de suelo para regadíos, al objeto de decidir el momento y volumen de agua óptimo a emplear en cada turno de riego, minimizando así el consumo de agua.Fondo Europeo para el Desarrollo Regional (FEDER)Programa Nacional de Tecnologías de Información y las Comunicaciones I+

A Front-End ASIC for a 3-D Magnetometer for Space Applications by Using Anisotropic Magnetoresistors

This paper presents an application-specific integrated circuit (ASIC) aimed for an alternative design of a digital 3-D magnetometer for space applications, with a significant reduction in mass and volume while maintaining a high sensitivity. The proposed system uses magnetic field sensors based on anisotropic magnetoresistances and a rad-hard mixed-signal ASIC designed in a standard 0.35 μm CMOS technology. The ASIC performs sensor-signal conditioning and analogue-to-digital conversion, and handles calibration tasks, system configuration, and communication with the outside. The proposed system provides high sensitivity to low magnetic fields, down to 3 nT, while offering a small and reliable solution under extreme environmental conditions in terms of radiation and temperature.Ministerio de Ciencia e Innovación AYA2011-29967-C05-05, AYA2009-14212-C05-04, AYA2008-06420-C04-0

Four-channel self-compensating single-slope ADC for space environments

A multichannel high-resolution single-slope analogue-to-digital converter (SS ADC) is presented that automatically compensates for process, voltage and temperature variations, as well as for radiation effects, in order to be used in extreme environmental conditions. The design combines an efficient implementation by using a feedback loop that ensures an inherently monotonic and very accurate ramp generation, with high levels of configurability in terms of resolution and conversion rate, as well as input voltage range. The SS ADC was designed in a standard 0.35 μm CMOS technology. Experimental measurements of the performance and stability against radiation and temperature are presented to verify the proposed approach

OWLs: A mixed-signal ASIC for optical wire-less links in space instruments

This paper describes the design of a mixed-signal ASIC for space application and the techniques employed for radiation hardening and temperature effects compensation. The work is part of a planned long-term effort and collaboration between "Instituto de Microelectrónica de Sevilla (IMSE)", "Universidad de Sevilla (US)", and "Instituto Nacional de Técnica Aeroespacial (INTA)" aimed to consolidate a group of experienced mixed-signal space-ASIC designers. The initiative is partially funded by the Spanish National Research Program. The ASIC performs the function of an optical digital transceiver for diffuse-light intra-satellite optical communications. It has been designed in a 0.35μm CMOS technology from austriamicrosystems (ams). The chip has been manufactured and verified from a functional perspective. Radiation characterization is planned for the third quarter of 2012. Power- and temperature-stress tests, as well as life-tests are also planned for this next quarter, and will be carried out by Alter Technology TÜV Nord S.A.U. Given the previous characterization of the technology [1] and the hardening techniques employed in the design and layout, radiation is not expected to be a problem. The specified environmental limits are a pedestal hard limit of 50KRads with the goal of maximizing TID tolerance, SEU and SET LET-thresholds above 70MeV/(mg/cm2), and latchup free behavior up to the same LET limit. Concerning temperature, the specified operation range is from -90 to +125ºC, while the non-operating temperature range is from -135 to +150ºC.Ministerio de Ciencia e Innovación (MICINN) MEIGA AYA2009-14212-C05-04, AYA2008-06420-C04-0

Review article of the current state of glaciers in the tropical Andes: a multi-century perspective on glacier evolution and climate change

The aim of this paper is to provide the community with a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the last three decades is unprecedented since the maximum extension of the LIA (mid 17th–early 18th century). In terms of changes in mass balance, although there have been some sporadic gains on several glaciers, we show that the trend has been quite negative over the past 50 yr, with a mean mass balance deficit for glaciers in the tropical Andes that is slightly more negative than the computed global average. A break point in the trend appeared in the late 1970s with mean annual mass balance per year decreasing from −0.2m w.e. in the period 1964–1975 to −0.76m w.e. in the period 1976–2010. In addition, even if glaciers are currently retreating everywhere in the tropical Andes, it should be noted that as a percentage, this is much more pronounced on small glaciers at low altitudes that do not have a permanent accumulation zone, and which could disappear in the coming years/decades. Monthly mass balance measurements performed in Bolivia, Ecuador and Colombia showed that variability of the surface temperature of the Pacific Ocean is the main factor governing variability of the mass balance variability at the interannual to decadal time scale. Precipitation did not display a significant trend in the tropical Andes in the 20th century, and consequently cannot explain the glacier recession. On the other hand, temperature increased at a significant rate of 0.10◦Cdecade−1 in the last 70 yr. The higher frequency of El Nin ̃o events and changes in its spatial and temporal occurrence since the late 1970s together with a warming troposphere over the tropical Andes may thus explain much of the recent dramatic shrinkage of glaciers in this part of the world

Future voyages to the solar system

CHALLENGE 2: FUTURE VOYAGES TO THE SOLAR SYSTEMPeer reviewe

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

The Mars Environmental Dynamics Analyzer, MEDA. A Suite of Environmental Sensors for the Mars 2020 Mission

86 pags, 49 figs, 24 tabsNASA's Mars 2020 (M2020) rover mission includes a suite of sensors to monitor current environmental conditions near the surface of Mars and to constrain bulk aerosol properties from changes in atmospheric radiation at the surface. The Mars Environmental Dynamics Analyzer (MEDA) consists of a set of meteorological sensors including wind sensor, a barometer, a relative humidity sensor, a set of 5 thermocouples to measure atmospheric temperature at ∼1.5 m and ∼0.5 m above the surface, a set of thermopiles to characterize the thermal IR brightness temperatures of the surface and the lower atmosphere. MEDA adds a radiation and dust sensor to monitor the optical atmospheric properties that can be used to infer bulk aerosol physical properties such as particle size distribution, non-sphericity, and concentration. The MEDA package and its scientific purpose are described in this document as well as how it responded to the calibration tests and how it helps prepare for the human exploration of Mars. A comparison is also presented to previous environmental monitoring payloads landed on Mars on the Viking, Pathfinder, Phoenix, MSL, and InSight spacecraft.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects No. ESP2014-54256-C4-1-R (also -2-R, -3-R and -4-R) and AYA2015-65041-P; Ministry of Science, Innovation and Universities, projects No. ESP2016-79612-C3-1-R (also -2-R and -3-R), ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also -C32 and -C33) and RTI2018-099825-B-C31; Instituto Nacional de Tecnica Aeroespacial; Ministry of Science and Innovation's Centre for the Development of Industrial Technology; Grupos Gobierno Vasco IT1366-19; and European Research Council Consolidator Grant no 818602.Peer reviewe