Long path monitoring of tropospheric O3, NO2, H2CO and SO2

Concentrations of tropospheric O3, NO2, H2CO, and SO2 have been measured on the Campus of the 'Universite Libre de Bruxelles' on a routine basis since October 1990. The long path system consists of a source lamp, a first 30 cm f/8 Cassegrain type telescope which collimates the light onto a slightly parabolic mirror placed on the roof of a building situated 394 m away from the laboratory. The light is sent back into a second 30 cm Cassegrain telescope. This telescope has been modified so that the output beam is a 5 cm diameter parallel beam. This beam is then focused onto the entrance aperture of the BRUKER IFS120HR fourier transform spectrometer. The two telescopes are mounted on alignment devices and the external mirror is equipped with a driving system operated from the laboratory. The choice of the light source (either a 1000 W high pressure 'ozone free' xenon lamp or a 250 W tungsten filament) and of the detector (either a solar blind UV-diode or a silicon diode) depended on the spectral region studied. These regions lie respectively from 26,000 cm(exp -1) to 30,000 cm(exp -1) (260-380 nm) and from 14,000 cm(exp -1) to 30,000 cm(exp -1) (330-700 nm). The spectra have been recorded at the resolution of 16 cm(exp -1) and with a dispersion of 7.7 cm(exp -1). They have been measured during the forward and the backward movements of the mobile mirror, in double sided mode; each spectrum is an average of 2000 scans. The time required to record a spectrum is about 45 minutes. The shape of the raw spectra in the two investigated regions are represented

Participation of women scientists in ESA solar system missions: A historical trend

We analyzed the participation of women scientists in 10 ESA (European Space Agency) Solar System missions over a period of 38 years. Being part of a spacecraft mission science team can be considered a proxy to measure the "success"in the field. Participation of women in PI (Principal Investigators) teams varied between 4% and 25 %, with several missions with no women as PI. The percentage of female scientists as Co-I (Co-Investigators) is always less than 16 %. This number is lower than the percentage of women in the International Astronomical Union from all ESA's Member State (24 %), which can give us an indication of the percentage of women in the field. We encountered many difficulties to gather the data for this study. The list of team members were not always easily accessible. An additional difficulty was to determine the percentage of female scientists in planetary science in Europe. We would like to encourage the planetary community as a whole, as well as international organizations, universities and societies to continuously gather statistics over many years. Detailed statistics are only the first step to closely monitor the development of achievement gaps and initiate measures to tackle potential causes of inequity, leading to gender inequalities in STEM careers

Detecting Venus’ volcanic gas plumes with VenSpec-H

International audienceThe VenSpec-H instrument is part of the EnVision payload which is currently being evaluated by ESA for mission selection. EnVision is a medium class mission to determine the nature and current state of geological activity on Venus, and its relationship with the atmosphere, to understand how Venus and Earth could have evolved so differently. VenSpec-H is part of the VenSpec suite [1], including also an IR mapper and a UV spectrometer [2] suite. The science objectives of this suite are to search for temporal variations in surface temperatures and tropospheric concentrations of volcanically emitted gases, indicative of volcanic eruptions; and study surface-atmosphere interactions and weathering by mapping surface emissivity and tropospheric gas abundances. Recent and perhaps ongoing volcanic activity has been inferred in data from both Venus Express an

Cell arrest and cell death in mammalian preimplantation development

The causes, modes, biological role and prospective significance of cell death in preimplantation development in humans and other mammals are still poorly understood. Early bovine embryos represent a very attractive experimental model for the investigation of this fundamental and important issue. To obtain reference data on the temporal and spatial occurrence of cell death in early bovine embryogenesis, three-dimensionally preserved embryos of different ages and stages of development up to hatched blastocysts were examined in toto by confocal laser scanning microscopy. In parallel, transcript abundance profiles for selected apoptosis-related genes were analyzed by real-time reverse transcriptase-polymerase chain reaction. Our study documents that in vitro as well as in vivo, the first four cleavage cycles are prone to a high failure rate including different types of permanent cell cycle arrest and subsequent non-apoptotic blastomere death. In vitro produced and in vivo derived blastocysts showed a significant incidence of cell death in the inner cell mass (ICM), but only in part with morphological features of apoptosis. Importantly, transcripts for CASP3, CASP9, CASP8 and FAS/FASLG were not detectable or found at very low abundances. In vitro and in vivo, errors and failures of the first and the next three cleavage divisions frequently cause immediate embryo death or lead to aberrant subsequent development, and are the main source of developmental heterogeneity. A substantial occurrence of cell death in the ICM even in fast developing blastocysts strongly suggests a regular developmentally controlled elimination of cells, while the nature and mechanisms of ICM cell death are unclear. Morphological findings as well as transcript levels measured for important apoptosis-related genes are in conflict with the view that classical caspase-mediated apoptosis is the major cause of cell death in early bovine development

No phosphine in the atmosphere of Venus

The detection of phosphine (PH₃) has been recently reported in the atmosphere of Venus employing mm-wave radio observations (Greaves et at. 2020). We here demonstrate that the observed PH₃ feature with JCMT can be fully explained employing plausible mesospheric SO₂ abundances (~100 ppbv as per the SO₂ profile given in their figure 9), while the identification of PH₃ in the ALMA data should be considered invalid due to severe baseline calibration issues. We demonstrate this by independently calibrating and analyzing the ALMA data using different interferometric analysis tools, in which we observe no PH₃ in all cases. Furthermore, for any PH₃ signature to be produced in either ALMA or JCMT spectra, PH₃ needs to present at altitudes above 70 km, in stark disagreement with their photochemical network. We ultimately conclude that this detection of PH₃ in the atmosphere of Venus is not supported by our analysis of the data

Martian Atmospheric Temperature and Density Profiles During the First Year of NOMAD/TGO Solar Occultation Measurements

We present vertical profiles of temperature and density from solar occultation (SO) observations by the “Nadir and Occultation for Mars Discovery” (NOMAD) spectrometer on board the Trace Gas Orbiter during its first operational year, which covered the second half of Mars Year 34. We used calibrated transmittance spectra in 380 scans, and apply an in-house pre-processing to clean data systematics. Temperature and CO2 profiles up to about 90 km, with consistent hydrostatic adjustment, are obtained, after adapting an Earth-tested retrieval scheme to Mars conditions. Both pre-processing and retrieval are discussed to illustrate their performance and robustness. Our results reveal the large impact of the MY34 Global Dust Storm (GDS), which warmed the atmosphere at all altitudes. The large GDS aerosols opacity limited the sounding of tropospheric layers. The retrieved temperatures agree well with global climate models (GCM) at tropospheric altitudes, but NOMAD mesospheric temperatures are wavier and globally colder by 10 K in the perihelion season, particularly during the GDS and its decay phase. We observe a warm layer around 80 km during the Southern Spring, especially in the Northern Hemisphere morning terminator, associated to large thermal tides, significantly stronger than in the GCM. Cold mesospheric pockets, close to CO2 condensation temperatures, are more frequently observed than in the GCM. NOMAD CO2 densities show oscillations upon a seasonal trend that track well the latitudinal variations expected. Results uncertainties and suggestions to improve future data re-analysis are briefly discussed

The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter

The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 μm—the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7–1.6 μm spectral range with a resolving power of ∼20,000. NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the 2.2–4.4 μm range. MIR achieves a resolving power of >50,000. It has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere. The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7–17 μm with apodized resolution varying from 0.2 to 1.3 cm−1. TIRVIM is primarily dedicated to profiling temperature from the surface up to ∼60 km and to monitor aerosol abundance in nadir. TIRVIM also has a limb and solar occultation capability. The technical concept of the instrument, its accommodation on the spacecraft, the optical designs as well as some of the calibrations, and the expected performances for its three channels are described