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Here we present water vapor vertical profiles observed with the ExoMars Trace Gas Orbiter/Nadir and Occultation for MArs Discovery instrument during the perihelion and Southern summer solstice season (LS = 240°–300°) in three consecutive Martian Years 34, 35, and 36. We show the detailed latitudinal distribution of H2O at tangent altitudes from 10 to 120 km, revealing a vertical plume at 60°S–50°S injecting H2O upward, reaching abundance of about 50 ppmv at 100 km. We have observed this event repeatedly in the three Martian years analyzed, appearing at LS = 260°–280° and showing inter‐annual variations in the magnitude and timing due to long term effects of the Martian Year 34 Global Dust Storm. We provide a rough estimate of projected hydrogen escape of 3.2 × 109 cm−2 s−1 associated to these plumes, adding further evidence of the key role played by the perihelion season in the long term evolution of the planet's climate. Plain Language Summary: Studying the vertical distribution of the Martian atmosphere is crucial to understand what happened to the water presumably present in larger abundance on ancient Mars. We have analyzed the vertical profiles of three Martian Years during the Southern summer, revealing a strong vertical transport of water vapor to the upper atmosphere. This seasonal phenomenon seems to be repeated annually, although with variations in the location and time of the year. Our estimation of the associated upward hydrogen flux represents an important loss which could have contributed to the escape of water to space for at least the period in which Mars had its present orbital inclination. Key Points: Latitudinal distributions of water vapor up to 120 km are analyzed in detail using Nadir and Occultation for MArs Discovery (NOMAD) observations with an improved retrieval schemeWater vapor injection during the perihelion localized around 50°–60°S in three consecutive Martian yearsMartian year 34 Global Dust Storm may have affected the driving mechanisms of the plume, delaying its appearance and reducing its magnitude [ABSTRACT FROM AUTHOR]

In an attempt to understand the findings presented in the Comment by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539), we followed their data analysis methodology, omitting the hot and cold‐load calibrations that are an important part of the standard SOFIA GREAT instrument calibration procedure. This process requires scaling of the Venus off‐source spectra by an arbitrary factor, which in turn introduces residuals of the intrinsic receiver bandpass shape as spurious components in the resulting line/continuum spectra. Although these additional artifacts can be reduced via Fourier‐domain spectral filtering, their removal depends on an ill‐constrained interpolation of the Venus continuum across the PH3 spectral line positions, resulting in an unreliable final spectrum. We therefore conclude that the PH3 lines claimed to be detected in the Comment by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539) originate from data/analysis artifacts, and confirm our original result that there is no evidence for phosphine in the SOFIA Venus data. Plain Language Summary: We performed observations using a unique, flying telescope—the Stratospheric Observatory for Infrared Astronomy (SOFIA)—to search for a gas called phosphine in the atmosphere of Venus, which has been suggested to be an indicator for life. The observations, published by Cordiner et al. (2022, https://doi.org/10.1029/2022gl101055), were analyzed carefully but showed no evidence of phosphine. Our findings were called into question in the Comment by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539), who claimed to find phosphine lines in the SOFIA observations after following an unconventional data analysis method. We have investigated their method, and conclude that it is likely to introduce spurious signals into the data, so the claimed phosphine detection is therefore not significant. Key Points: The revised calibration procedure adopted by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539) introduces additional receiver artifacts into the SOFIA 4G2 Venus spectraThe claimed PH3 detection is likely a result of this, combined with interpolation artifacts that occur during subsequent Fourier filteringWe confirm our original conclusion that there is no evidence for phosphine in the SOFIA GREAT Venus data [ABSTRACT FROM AUTHOR]

The water vapor in the Martian atmosphere plays a significant role in the planet's climate, being crucial in most of the chemical and radiative transfer processes. Despite its importance, the vertical distribution of H2O in the atmosphere has not still been characterized precisely enough. The recent ExoMars Trace Gas Orbiter mission, with its Nadir and Occultation for MArs Discovery instrument, has allowed us to measure the H2O vertical distribution with unprecedented resolution. Recent studies of vertical profiles have shown that high dust concentration in the atmosphere, in particular during dust storms, induces an efficient transport of the H2O to higher altitudes, from 40 km up to 80 km. We study the H2O vertical distribution in a subset of solar occultations during the perihelion of two Martian years (MYs), including the 2018 Global Dust Storm (GDS), in order to compare the same Martian season under GDS and non‐GDS conditions. We present our state‐of‐the‐art retrieval scheme, and we apply it to a combination of two diffraction orders, which permits sounding up to about 100 km. We confirm recent findings of H2O increasing at high altitudes during Ls = 190°–205° in MY 34, reaching abundances of about 150 ppmv at 80 km in both hemispheres not found during the same period of MY 35. We found a hygropause's steep rising during the GDS from 30 up to 80 km. Furthermore, strong supersaturation events have been identified at mesospheric altitudes even in presence of water ice layers retrieved by the IAA team. Plain Language Summary: The characterization of water vapor in the atmosphere is important for understanding the cycle of water on Mars and it is crucial in most of the atmospheric processes taking place in its current climate. The observation technique of the Nadir and Occultation for Mars Discovery onboard ExoMars Trace Gas Orbiter using solar occultations allows a high resolution vertical sampling of the atmosphere, permitting characterization of the H2O vertical distribution. In this work, we analyze the H2O distribution in the Martian atmosphere during the southern spring in Martian years 34 and 35. A Global Dust Storm event during the first one allowed us to study the atmospheric H2O and its response in the same season under intense and regular dusty conditions. We found that during intense dust storms, water vapor is present at higher altitudes rather than in regular atmospheric dust activity. This shows high concentrations of about 150 ppmv up to 80 km. As a consequence of the dust intensification, we observed an increase in the altitude of the 50 ppmv water vapor layer. Here, we report observations of atmospheric layers where H2O abundances exceed the theoretical needed saturation limit even when small particles are present. Key Points: Water vapor vertical distributions during the first half of the Martian perihelion season are presented from two consecutive Martian yearsStrong impact of the 2018 Global Dust Storm in the H2O abundances during MY 34, showing an increase on the hygropause's altitude compared to MY 35Atmospheric supersaturation events with presence of water ice at mesospheric altitudes are reported [ABSTRACT FROM AUTHOR]

This article discusses a retrospective case-control study that evaluated the effectiveness and safety of valacyclovir in preventing congenital cytomegalovirus (CMV) infection during pregnancy. The study included 80 pregnant women with primary CMV infection, divided into two groups: one group received valacyclovir during pregnancy, while the other did not. The results showed that the presence of CMV DNA in the amniotic fluid was significantly lower in the group that received valacyclovir. Additionally, ultrasound anomalies and anomalies on fetal echocardiography were also lower in the valacyclovir group. The study concludes that valacyclovir is effective and safe in preventing congenital CMV infection. [Extracted from the article]

The Solar Occultation (SO) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument has been scanning the Martian atmosphere for almost 2 Martian years. In this work, we present a subset of the NOMAD SO data measured at the mesosphere at the terminator. From the data set, we investigated 968 vertical profiles of carbon dioxide density and temperature covering the Martian Year (MY) 35 as well as MY 36 up to a solar longitude (Ls) of 135° and altitudes around 60–100 km. While carbon dioxide density profiles are directly retrieved from the spectral signature in the spectra, temperature profiles are more challenging to retrieve as unlike density profiles, temperature profiles can present some spurious features if the regularization is not correctly managed. Comparing seven regularization methods, we found that the expected error estimation method provides the best regularization parameters. The vertical resolution of the profiles is on average 1.6 km. Numerous warm layers and cold pockets appear in this data set. The warm layers are found in the Northern hemisphere at dawn and dusk as well as in the Southern hemisphere at dawn. Strong warm layers are present in more than 13.5% of the profiles. The Southern hemisphere at dusk does not present any warm layer between Ls 50° and 150°. The height and latitudinal distribution of those warm layers were similar in MY 35 and MY 36 during the first half of the year (Ls = 0°–135°). Plain Language Summary: Martian mesosphere (the region of the atmosphere between 50 and 100 km in altitude) is the place where many large and small‐scale thermal features occur, which necessitates observations made at a fine spatial resolution. The Solar Occultation (SO) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument is an infrared spectrometer sensitive in a spectral range where CO2, H2O, CO, and CH4 have spectral signatures. NOMAD‐SO probes the Martian atmosphere with a high signal‐to‐noise ratio and a fine vertical sampling using the solar occultation technique. We implemented a scheme to fine‐tune the regularization of the vertical profiles leading to the best possible resolution of the retrieved profiles. We show here almost a year and a half of the measurements of carbon dioxide density and temperature of the Mars mesosphere at the terminator, that is, the separation between the day side and the night side. On average, the mesosphere is characterized by a decrease in the temperature with height. At the high resolution achieved here, we highlight many warmer layers in the Northern hemisphere and also in the Southern hemisphere at dawn but not at dusk. Stronger warm layers are found around the perihelion. Key Points: We show global vertical distributions of CO2 and temperature with high resolution in the Mars mesosphere at the terminatorMany mesospheric temperature profiles at the terminator present an inversion layer with a warm layer around 0.1 PaThe distribution of warm layers is similar in Martian years 35 and 36. Warm layers are absent at dusk in the South hemisphere at Ls 50°–150° [ABSTRACT FROM AUTHOR]

The Solar Occultation (SO) channel of the Nadir and Occultation for Mars Discovery (NOMAD) instrument scans the Martian atmosphere since 21 April 2018. In this work, we present a subset of the NOMAD SO data measured at the mesosphere. We focused on a spectral range that started to be recorded in Martian year (MY) 35. A total of 968 vertical profiles of carbon dioxide density and temperature covering MY 35 and the beginning of MY 36 were investigated until 135° of solar longitude. We compared 47 profiles with co‐located profiles of the Mars Climate Sounder onboard the Mars Reconnaissance Orbiter. Most profiles show a good agreement as SO temperatures are only 1.8 K higher, but some biases lead to an average absolute difference of 7.4°K. The SO data set is also compared with simulations from the Global Environmental Multiscale‐Mars general circulation model. Both data sets are in good agreement except for the presence of a cold layer in the winter hemisphere and a warm layer at dawn in the Northern hemisphere for solar longitudes between 240° and 360°. Five profiles contain temperatures lower than the limit for CO2 condensation. Strong warm layers were found in 13.5% of the profiles. They are present mainly at dawn and in the winter hemisphere, while the Northern dusks appear featureless. The data set mainly covers high latitudes around 60° and we derived some non‐migrating tides. In the Southern winter hemisphere, we derived apparent zonal wavenumber‐1 (WN‐1) and WN‐3 tidal components with a maximum amplitude of 10% and 5% at 63 km, respectively. Plain Language Summary: The vertical profiles analyzed in this work extend over more than a Martian year (687 days) and are located in the mesosphere (50–100 km altitude) at the transition between the day and night sides. Temperature can sometimes be so low that CO2 ice clouds form. Here, we report some features in our data set that are likely due to those CO2 ice clouds. We also report some warm layers which appear in the winter hemisphere, and we analyzed the components of the apparent atmospheric tides at the terminator. We compared our results to highlight possible biases with data from another instrument (Mars Climate Sounder) and a model (Global Environmental Multiscale‐Mars). The measured temperatures are higher than those of the model in the winter hemisphere. Compared to the other instrument, we find similar profile curves but with stronger variations in our profiles, probably due to a higher vertical resolution. Key Points: We show vertical distributions of temperature with high vertical resolution in the Mars mesosphere at the terminatorThe retrieved temperatures show a good agreement with the results measured by Mars Climate Sounder/Mars Reconnaissance Orbiter and a general circulation modelThe temperature has distinct features such as tidal components, warm layers, and cold layers below the CO2 condensation temperature [ABSTRACT FROM AUTHOR]

The presence of phosphine (PH3) in the atmosphere of Venus was reported by Greaves et al. (2021, https://doi.org/10.1038/s41550-020-1174-4), based on observations of the J = 1–0 transition at 267 GHz using ground‐based, millimeter‐wave spectroscopy. This unexpected discovery presents a challenge for our understanding of Venus's atmosphere, and has led to a reappraisal of the possible sources and sinks of atmospheric phosphorous‐bearing gases. Here we present results from a search for PH3 on Venus using the German REceiver for Astronomy at Terahertz Frequencies instrument aboard the Stratospheric Observatory for Infrared Astronomy aircraft, over three flights conducted in November 2021. Multiple PH3 transitions were targeted at frequencies centered on 533 and 1,067 GHz, but no evidence for atmospheric PH3 was detected. Through radiative transfer modeling, we derived a disk‐averaged upper limit on the PH3 abundance of 0.8 ppb in the altitude range 75–110 km, which is more stringent than previous ground‐based studies. Plain Language Summary: We performed observations using a unique, flying telescope—the Stratospheric Observatory for Infrared Astronomy—to search for a gas called phosphine (PH3) in the atmosphere of Venus, which has been suggested to be an indicator for life. Our observations showed no evidence of PH3, in contrast to the original claim, and we provide a stringent upper limit on its abundance. Two other recent studies using different telescopes also found no evidence for PH3 on Venus, in agreement with our present result. Key Points: A recent detection of phosphine (PH3) (a possible biomarker) on Venus at millimeter wavelengths has been called into question by subsequent workWe performed far‐infrared spectroscopic observations of Venus using the German REceiver for Astronomy at Terahertz Frequencies instrument onboard the Stratospheric Observatory for Infrared Astronomy aircraftPH3 was not detected, and a strict upper limit on its atmospheric abundance of 0.8 ppb was derived between 75 and 110 km [ABSTRACT FROM AUTHOR]

We show a positive vertical correlation between ozone and water ice using a vertical cross‐correlation analysis with observations from the ExoMars Trace Gas Orbiter's Nadir and Occultation for Mars Discovery instrument. This is particularly apparent during LS = 0°–180°, Mars Year 35 at high southern latitudes, when the water vapor abundance is low. Ozone and water vapor are anti‐correlated on Mars; Clancy et al. (2016, https://doi.org/10.1016/j.icarus.2015.11.016) also discuss the anti‐correlation between ozone and water ice. However, our simulations with gas‐phase‐only chemistry using a 1‐D model show that ozone concentration is not influenced by water ice. Heterogeneous chemistry has been proposed as a mechanism to explain the underprediction of ozone in global climate models (GCMs) through the removal of HOx. We find improving the heterogeneous chemical scheme by creating a separate tracer for the HOx adsorbed state, causes ozone abundance to increase when water ice is present (30–50 km), better matching observed trends. When water vapor abundance is high, there is no consistent vertical correlation between observed ozone and water ice and, in simulated scenarios, the heterogeneous chemistry has a minor influence on ozone. HOx, which are by‐products of water vapor, dominate ozone abundance, masking the effects of heterogeneous chemistry on ozone, and making adsorption of HOx have a negligible impact on ozone. This is consistent with gas‐phase‐only modeled ozone, showing good agreement with observations when water vapor is abundant. Overall, the inclusion of heterogeneous chemistry improves the ozone vertical structure in regions of low water vapor abundance, which may partially explain GCM ozone deficits. Plain Language Summary: Ozone gas is found in small quantities in the martian atmosphere, highly variable both in time and space. Ozone quantity is controlled by photochemical reactions involving other species too difficult to detect with remote sensing. Two main ways ozone is destroyed in the martian atmosphere are by: (a) absorbing ultraviolet sunlight; (b) reacting with hydroxyl radicals, highly reactive chemicals formed by water vapor absorbing ultraviolet sunlight. The latter leads to a well‐known anti‐correlation between ozone and water vapor. Ozone is underpredicted in climate models, implying chemical reactions are missing or incorrect in models. We investigate reactions between hydroxyl radicals and water ice as a potential explanation for the ozone underprediction by using a model and observed vertical profiles. We find observed ozone and water ice have a positive vertical correlation and, when simulating a model with improved chemistry, ozone abundance increases at altitudes where water ice is present due to the decrease in hydroxyl radicals. However, in areas where water vapor is abundant, no such correlation is seen and the chemistry has little impact on modeled ozone. This is due to large abundances of hydroxyl radicals which inhibit the increase in ozone caused by the addition of the improved chemistry. Key Points: Observed ozone and water ice profiles show a positive vertical correlation, contrary to global ozone and water vapor column anti‐correlationHeterogeneous chemistry increases ozone abundance at altitudes where water ice is present, matching locations where ozone is underpredictedHigh hydroxyl radical abundance, assumed proportional to high water vapor abundance, masks the effects of heterogeneous chemistry on ozone [ABSTRACT FROM AUTHOR]

To understand the evolving martian water cycle, a global perspective of the combined vertical and horizontal distribution of water is needed in relation to supersaturation and water loss and how it varies spatially and temporally. The global vertical water vapor distribution is investigated through an analysis that unifies water, temperature and dust retrievals from several instruments on multiple spacecraft throughout Mars Year (MY) 34 with a global circulation model. During the dusty season of MY 34, northern polar latitudes are largely absent of water vapor below 20 km with variations above this altitude due to transport from mid‐latitudes during a global dust storm, the downwelling branch of circulation during perihelion season and the intense MY 34 southern summer regional dust storm. Evidence is found of supersaturated water vapor breaking into the northern winter polar vortex. Supersaturation above around 60 km is found for most of the time period, with lower altitudes showing more diurnal variation in the saturation state of the atmosphere. Discrete layers of supersaturated water are found across all latitudes. The global dust storm and southern summer regional dust storm forced water vapor at all latitudes in a supersaturated state to 60–90 km where it is more likely to escape from the atmosphere. The reanalysis data set provides a constrained global perspective of the water cycle in which to investigate the horizontal and vertical transport of water throughout the atmosphere, of critical importance to understand how water is exchanged between different reservoirs and escapes the atmosphere. Plain Language Summary: To better understand how water vapor is transported throughout the atmosphere requires a global perspective of the combined vertical and horizontal distribution of water. By combining a simulation of the martian atmosphere with satellite observations of water, temperature and dust from multiple spacecraft we can investigate the water vapor cycle and the physical processes that result in the observed vertical distribution of water vapor. We find that circulation patterns during major dust storms and the southern summer season have a strong influence on the vertical distribution of water allowing it to reach much higher altitudes (than usually found in less dusty conditions or different seasons) and potentially escape the atmosphere. Supersaturation (when relative humidity is beyond 100%) occurs frequently in the martian atmosphere and this study finds that it allows water vapor to break into the northern winter polar vortex, suggesting the winter polar vortex is less of a boundary to transport of chemical species than previously thought. Key Points: Global dust storm and southern summer regional dust storm events pushed water vapor above 60 km across all latitudesThe saturation state of the global atmosphere is investigated in a reanalysis for the first timeSupersaturated water vapor penetrates the northern winter polar vortex [ABSTRACT FROM AUTHOR]

We present water vapor vertical distributions on Mars retrieved from 3.5 years of solar occultation measurements by Nadir and Occultation for Mars Discovery onboard the ExoMars Trace Gas Orbiter, which reveal a strong contrast between aphelion and perihelion water climates. In equinox periods, most of water vapor is confined into the low‐middle latitudes. In aphelion periods, water vapor sublimated from the northern polar cap is confined into very low altitudes—water vapor mixing ratios observed at the 0–5 km lower boundary of measurement decrease by an order of magnitude at the approximate altitudes of 15 and 30 km for the latitudes higher than 50°N and 30–50°N, respectively. The vertical confinement of water vapor at northern middle latitudes around aphelion is more pronounced in the morning terminators than evening, perhaps controlled by the diurnal cycle of cloud formation. Water vapor is also observed over the low latitude regions in the aphelion southern hemisphere (0–30°S) mostly below 10–20 km, which suggests north‐south transport of water still occurs. In perihelion periods, water vapor sublimated from the southern polar cap directly reaches high altitudes (>80 km) over high southern latitudes, suggesting more effective transport by the meridional circulation without condensation. We show that heating during perihelion, sporadic global dust storms, and regional dust storms occurring annually around 330° of solar longitude (LS) are the main events to supply water vapor to the upper atmosphere above 70 km. Plain Language Summary: This study presents new details on the global distribution of Mars water vapor altitude profile based on the daily observations for 3.5 years. We show a strong contrast between northern and southern summer when water vapor is sublimated from the summer polar ice. We find that sublimated water vapor is confined at low altitudes in the northern summer, whereas it directly reaches the upper atmosphere in the southern summer. During solstice periods, global meridional transport from summer to winter hemisphere drives the water vapor distributions. It is suggested that the transport of water vapor by the global circulation is limited by the formation of ice clouds in the northern summer. In contrast, water vapor is more effectively transported to the winter hemisphere in the southern summer because its vertical extent is less constrained by cloud formation in the warm southern summer atmosphere. We show that southern summer is the primary season for the supply of water vapor to the upper atmosphere, in addition to the period of strong dust storms. We also show that water transport from north to south still occurs below 10–20 km in the northern summer season, however it is much reduced relative to the southern summer season. Key Points: We present global vertical distributions of water vapor in the Mars atmosphere from the observations collected for 3.5 yearsWe confirm a strong contrast between aphelion and perihelion water vapor vertical distributionsWe reveal that water vapor sublimated from the northern polar cap is confined into very low altitudes during the aphelion periods [ABSTRACT FROM AUTHOR]

The vertical profiles of water vapor and its semi‐heavy hydrogen isotope HDO provided by instruments on ExoMars Trace Gas Orbiter constitute a unique new data set to understand the Martian water cycle including its isotopic composition. As water vapor undergoes hydrogen isotopic fractionation upon deposition (but not sublimation), the D/H isotopic ratio in water is a tracer of phase transitions, and a key quantity to understand the long‐term history of water on Mars. Here, we present 3D global simulations of D/H in water vapor and compare them to the vertically resolved observations of D/H and water ice clouds taken by NOMAD during the second half of Mars year 34. D/H is predicted to be constant with height up to the main cloud level, above which it drops because of strong fractionation, explaining the upper cut‐off in the NOMAD observations when HDO drops below detectability. During the global and regional dust storms of 2018/2019, we find that HDO ascends with H2O, and that the D/H ratio is constant and detectable up to larger heights. The simulations are within the provided observational uncertainties over wide ranges in season, latitude and height. Our work provides evidence that the variability of the D/H ratio in the lower and middle atmosphere of Mars is controlled by fractionation on water ice clouds, and thus modulated by diurnally and seasonally varying cloud formation. We find no evidence of other processes or reservoirs that would have a significant impact on the D/H ratio in water vapor. Plain Language Summary: The isotopic composition of atmospheric water on Mars provides insights about the phase transitions in the water cycle, because the light (H2O) and semi‐heavy (HDO) form of water vapor deposit at different saturation pressures. Knowing the isotopic composition of atmospheric water also provides insights on the long‐term evolution of water on Mars. The NOMAD instrument on ExoMars Trace Gas Orbiter provided the first vertical profiles of the D/H ratio in water vapor on Mars. The data set shows a large variability with season and latitude. To understand this behavior, a general circulation model is required. We provide detailed simulations of the D/H ratio in Martian water vapor and compare them with the NOMAD observations. The model predicts that the D/H ratio is constant in the lower atmosphere and decreases across a layer of strong cloud formation that varies with season. During the global dust storm of 2018, this cloud layer was severely lifted. The simulations compare well to the observations, both out and in the dust storm, and explain their upper cut‐off by this predicted decrease in D/H. No other processes than cloud formation, nor special surface ice reservoirs with strongly different D/H values, were needed to reproduce the observations. Key Points: Hydrogen fractionation by clouds in Mars water vapor is simulated and evaluated with NOMAD D/H observations in and out of dust stormsThe model D/H ratio is constant and drops when clouds form, explaining the upper cut‐off in the NOMAD profiles as HDO becomes undetectableNOMAD water ice observations provide evidence that fractionation by clouds is the main factor controlling the HDO distribution on Mars [ABSTRACT FROM AUTHOR]

Slightly less than a Martian Year of nominal science (March 2018–January 2020) with the ExoMars Trace Gas Orbiter has furthered the ongoing investigation of dayside water vapor column abundance. These dayside observations span latitudes between 75°S and 75°N, and all longitudes, which can provide global snapshots of the total water column abundances. In addition to tracking the seasonal transport of water vapor between poles, geographic enhancements are noted, particularly in the southern hemisphere, both in Hellas Basin, and in other regions not obviously correlated to topography. We report consistent water vapor climatology with previous spacecraft observations, however, note a difference in total water vapor content is noted. Finally, we are unable to find evidence for substantial diurnal variation in the total dayside water vapor column. Plain Language Summary: This work provides the first look at the ExoMars Trace Gas Orbiter's ability to track atmospheric water vapor on the day side of Mars, through downward looking observations. Water vapor is reported in a series of maps, with respect to geography and season, and find consistent water vapor climatology with precious spacecraft observations. These maps inform our understanding of where Martian water vapor moves throughout the year and where it is concentrated. Key Points: Water vapor can be retrieved robustly from the Nadir and Occultation for MArs Discovery limb and Nadir observatory nadir observations for most dayside conditionsRetrieved water vapor columns demonstrate volatile transport, geographic variations, and lack of evidence for daytime local variationsTrace Gas Orbiter observations continue the legacy of monitoring the Martian water cycle and will contribute to future modeling efforts [ABSTRACT FROM AUTHOR]

Hydrogen chloride (HCl) was recently discovered in the atmosphere of Mars by two spectrometers onboard the ExoMars Trace Gas Orbiter. The reported detection made in Martian Year 34 was transient, present several months after the global dust storm during the southern summer season. Here, we present the full data set of vertically resolved HCl detections obtained by the NOMAD instrument, which covers also Martian year 35. We show that the particular increase of HCl abundances in the southern summer season is annually repeated, and that the formation of HCl is independent from a global dust storm event. We also find that the vertical distribution of HCl is strikingly similar to that of water vapor, which suggests that the uptake by water ice clouds plays an important role. The observed rapid decrease of HCl abundances at the end of the southern summer would require a strong sink independent of photochemical loss. Plain Language Summary A new species, hydrogen chloride (HCl), was recently discovered in the atmosphere Mars. Whereas, this gas plays a key role in the atmospheric chemistry on Earth and Venus, the chlorine cycle on Mars is not understood. HCl was found just after the global dust storm, so a connection between the storm and appearance of HCl was suggested. This study shows that HCl is detected even in a year without a global dust storm, which demonstrates that the formation of HCl is primary independent from global dust storms. This study also finds that the vertical distributions of HCl and water vapor are strikingly similar in shape. As the vertical profile of water vapor is controlled by the formation of water ice clouds, it suggests that HCl is taken up by water ice clouds. Finally, we observe that HCl is rapidly disappearing at the end of the southern summer on Mars. We demonstrate that this fast destruction cannot be explained by the standard photochemistry, which suggests that another (unknown) process plays a key role. [ABSTRACT FROM AUTHOR]

The Nadir and Occultation for MArs Discovery (NOMAD) instrument on board ExoMars Trace Gas Orbiter measured a large increase in water vapor at altitudes in the range of 40–100 km during the 2018 global dust storm on Mars. Using a three‐dimensional general circulation model, we examine the mechanism responsible for the enhancement of water vapor in the upper atmosphere. Experiments with different prescribed vertical profiles of dust show that when more dust is present higher in the atmosphere, the temperature increases, and the amount of water ascending over the tropics is not limited by saturation until reaching heights of 70–100 km. The warmer temperatures allow more water to ascend to the mesosphere. Photochemical simulations show a strong increase in high‐altitude atomic hydrogen following the high‐altitude water vapor increase by a few days. Plain Language Summary: The ExoMars Trace Gas Orbiter (TGO) is currently in orbit around Mars measuring the composition of the atmosphere. TGO was able to make observations before, during, and after a large planet‐encircling dust storm that occurred from June to August 2018. The TGO measurements provide the first opportunity to observe how water vapor is distributed with height in the atmosphere during a global‐scale dust event. It was found that there was a large increase in water vapor very high (40–100 km) in the atmosphere during the dust storm. Using a three‐dimensional numerical model of the Mars atmosphere, we found that when dust from the storm is transported up to levels above ~40 km, it warms the atmosphere due to solar absorption, and this in turn prevents ice clouds from forming at heights of 40–60 km and allows more water vapor to ascend to greater heights in the atmosphere. This is of interest in terms of the planetary evolution, as water molecules at greater heights are more readily dissociated by sunlight and lost from the atmosphere. This is an important factor for understanding the changes that have occurred since the period when surface features on Mars indicate that liquid water was present. Key Points: Transport of water vapor is simulated during the 2018 global dust storm on Mars in the GEM‐Mars General Circulation ModelThe simulation explains NOMAD observations of enhanced high‐altitude water abundances during the global dust stormThe vertical distribution of dust is a key factor for the transport of water vapor through the equatorial hygropause [ABSTRACT FROM AUTHOR]

It has been suggested that dust storms efficiently transport water vapor from the near‐surface to the middle atmosphere on Mars. Knowledge of the water vapor vertical profile during dust storms is important to understand water escape. During Martian Year 34, two dust storms occurred on Mars: a global dust storm (June to mid‐September 2018) and a regional storm (January 2019). Here we present water vapor vertical profiles in the periods of the two dust storms (Ls = 162–260° and Ls = 298–345°) from the solar occultation measurements by Nadir and Occultation for Mars Discovery (NOMAD) onboard ExoMars Trace Gas Orbiter (TGO). We show a significant increase of water vapor abundance in the middle atmosphere (40–100 km) during the global dust storm. The water enhancement rapidly occurs following the onset of the storm (Ls~190°) and has a peak at the most active period (Ls~200°). Water vapor reaches very high altitudes (up to 100 km) with a volume mixing ratio of ~50 ppm. The water vapor abundance in the middle atmosphere shows high values consistently at 60°S‐60°N at the growth phase of the dust storm (Ls = 195°–220°), and peaks at latitudes greater than 60°S at the decay phase (Ls = 220°–260°). This is explained by the seasonal change of meridional circulation: from equinoctial Hadley circulation (two cells) to the solstitial one (a single pole‐to‐pole cell). We also find a conspicuous increase of water vapor density in the middle atmosphere at the period of the regional dust storm (Ls = 322–327°), in particular at latitudes greater than 60°S. Plain Language Summary: The most striking phenomenon on Mars is a planet‐encircling storm, "global dust storm." Once it starts, the floating dust covers the whole atmosphere for more than several weeks. Recent studies suggest that dust storms effectively transport water vapor from the near‐surface to the middle atmosphere. In June to September 2018 and January 2019, a strong global dust storm and a regional storm occurred on Mars, respectively. This study investigates altitude profiles of water vapor in the Mars atmosphere measured during the dust storms, by using brand‐new measurements by Nadir and Occultation for Mars Discovery onboard the ExoMars Trace Gas Orbiter. We confirm that the water vapor expanded into the middle atmosphere, and we find that the water vapor reached very high altitudes (up to 100 km) during the dust storms. The dust storms intensify the atmospheric dynamics and heat the atmosphere. As a result, water vapor is lifted to higher altitudes and distributes along the meridional circulation. Key Points: We present vertical profiles of water vapor in the Martian atmosphere during global and regional dust storms in 2018‐2019We show a rapid and significant increase of water vapor in the middle atmosphere (40‐100 km) during both global and regional dust stormsWater vapor reaches very high altitudes, at least around 100 km, during the global dust storm [ABSTRACT FROM AUTHOR]

Objectives The aim of the study was to assess the rate, determinants, and outcomes of repeat pregnancies in women with HIV infection. Methods Data from a national study of pregnant women with HIV infection were used. Main outcomes were preterm delivery, low birth weight, CD4 cell count and HIV plasma viral load. Results The rate of repeat pregnancy among 3007 women was 16.2%. Women with a repeat pregnancy were on average younger than those with a single pregnancy (median age 30 vs. 33 years, respectively), more recently diagnosed with HIV infection (median time since diagnosis 25 vs. 51 months, respectively), and more frequently of foreign origin [odds ratio ( OR) 1.36; 95% confidence interval ( CI) 1.10-1.68], diagnosed with HIV infection in the current pregnancy ( OR: 1.69; 95% CI: 1.35-2.11), and at their first pregnancy ( OR: 1.33; 95% CI: 1.06-1.66). In women with sequential pregnancies, compared with the first pregnancy, several outcomes showed a significant improvement in the second pregnancy, with a higher rate of antiretroviral treatment at conception (39.0 vs. 65.4%, respectively), better median maternal weight at the start of pregnancy (60 vs. 61 kg, respectively), a higher rate of end-of-pregnancy undetectable HIV RNA (60.7 vs. 71.6%, respectively), a higher median birth weight (2815 vs. 2885 g, respectively), lower rates of preterm delivery (23.0 vs. 17.7%, respectively) and of low birth weight (23.4 vs. 15.4%, respectively), and a higher median CD4 cell count (+47 cells/μL), with almost no clinical progression to Centers for Disease Control and Prevention stage C ( CDC-C) HIV disease (0.3%). The second pregnancy was significantly more likely to end in voluntary termination than the first pregnancy (11.4 vs. 6.1%, respectively). Conclusions Younger and foreign women were more likely to have a repeat pregnancy; in women with sequential pregnancies, the second pregnancy was characterized by a significant improvement in several outcomes, suggesting that women with HIV infection who desire multiple children may proceed safely and confidently with subsequent pregnancies. [ABSTRACT FROM AUTHOR]

What's already known about this topic?Exposure to antiretroviral treatment in pregnancy does not seem to increase the risk of birth defects, but there is no information on the rate of prenatal detection of such defects. What does this study adds?We provide for the first time, in a national case series, information about prenatal detection rate in women with HIV (51.6% for any major defect, 66.7% for chromosomal abnormalities, and 85% for severe structural defects). [ABSTRACT FROM AUTHOR]

In this paper, the Annualized Agricultural Non-Point Source (AnnAGNPS) model has been used to estimate runoff, peak discharge and sediment load at the event scale in a Mediterranean watershed. The study area is the Carapelle torrent, Southern Italy (area = 506 km2), where continuous rainfall, streamflow and sediment load data are available. Nineteen flood events have been registered in the period 2007-2009 and were used for the application of the model. The aim of the paper is to evaluate the predictive accuracy of the model at the event scale, in a medium-size watershed, given the specific conditions of the semi-arid environments. A sensitivity analysis has been carried out to assign the correct parameterization: the mean normalized output variation of the most meaningful input parameters pointed out the influence of the curve number on runoff, peak discharge and sediment load predictions (values greater than 1); the MN Manning's roughness coefficient and K, C and P factors of the universal soil loss equation showed a moderate influence on sediment load simulations (values between 0·5 and 1). The selection of the Soil Conservation Service synthetic storm types has been based on the observed storm events analysis to improve the peak discharge simulations. The model prediction has proved to be good for runoff ( R2 = 0·74, NSE = 0·75, W = 0·92) and peak discharge ( R2 = 0·85, NSE = 0·70, W = 0·94), and satisfactory for sediment yield ( R2 = 0·70, NSE = 0·63, W = 0·91). The relative error is lower for high events; this result is quite interesting in semi-arid environments, where most of the annual sediment yield is concentrated in a few, severe events. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Objective We used data from a national study of pregnant women with HIV to evaluate the prevalence of congenital abnormalities in newborns from women with HIV infection. Design Observational study. Setting University and hospital clinics. Population Pregnant women with HIV exposed to antiretroviral treatment at any time during pregnancy. Methods The total prevalence of birth defects was assessed on live births, stillbirths, and elective terminations for fetal anomaly. The associations between potentially predictive variables and the occurrence of birth defects were expressed as odds ratios ( ORs) with 95% confidence intervals (95% CIs) for exposed versus unexposed cases, calculated in univariate and multivariate logistic regression analyses. Main outcome measures Birth defects, defined according to the Antiretroviral Pregnancy Registry criteria. Results A total of 1257 pregnancies with exposure at any time to antiretroviral therapy were evaluated. Forty-two cases with major defects were observed. The total prevalence was 3.2% (95% CI 1.9-4.5) for exposure to any antiretroviral drug during the first trimester (23 cases with defects) and 3.4% (95% CI 1.9-4.9) for no antiretroviral exposure during the first trimester (19 cases). No associations were found between major birth defects and first-trimester exposure to any antiretroviral treatment ( OR 0.94, 95% CI 0.51-1.75), main drug classes (nucleoside reverse transcriptase inhibitors, OR 0.95, 95% CI 0.51-1.76; non-nucleoside reverse transcriptase inhibitors, OR 1.20, 95% CI 0.56-2.55; protease inhibitors, OR 0.92, 95% CI 0.43-1.95), and individual drugs, including efavirenz (prevalence for efavirenz, 2.5%). Conclusions This study adds further support to the assumption that first-trimester exposure to antiretroviral treatment does not increase the risk of congenital abnormalities. [ABSTRACT FROM AUTHOR]

Over the past year, 2003-4, there have been a number of studies consolidating previous work in relation to pathogenesis of disease, diagnosis and management of Helicobacter pylori. Studies into the pathogenesis of disease have identified the main adhesin of H. pylori as an important virulence marker and as a potential target for therapy. Molecular investigations of both the strain and host variations have identified the action of several of the virulence factors, e.g. cagA, vacA, on disrupting host cell signalling and the consequences in respect of the release of chemokines from the damaged gastric epithelium and the effect on apoptosis. Over the past year, there have been further diagnostic kits developed based on modifications of current technology. Two promising areas of research for diagnosis are the use of host/strain genome polymorphisms as a means of identifying high-risk patients who may develop severe disease and the use of proteomics to identify potential antigens of diagnostic (or therapeutic) use. The three main antibiotics that are used in first-line eradication regimens are clarithromycin, metronidarzole and amoxycillin. Of these, metronidazole has the highest prevalence of resistance, followed by clarithromycin; amoxycillin resistance is only rarely reported. The decreasing success of current first-line therapy is the driving force for the development of new antibiotic combinations and a search for novel sources for chemotherapeutic agents and novel therapeutic targets. [ABSTRACT FROM AUTHOR]

7-11 November 2010, Tenth International Congress on Drug Therapy in HIV Infection, Glasgow, UK [ABSTRACT FROM AUTHOR]

Objective: We used data from a national study of pregnant women with HIV to evaluate the prevalence of congenital abnormalities in newborns from women with HIV infection., Design: Observational study., Setting: University and hospital clinics., Population: Pregnant women with HIV exposed to antiretroviral treatment at any time during pregnancy., Methods: The total prevalence of birth defects was assessed on live births, stillbirths, and elective terminations for fetal anomaly. The associations between potentially predictive variables and the occurrence of birth defects were expressed as odds ratios (ORs) with 95% confidence intervals (95% CIs) for exposed versus unexposed cases, calculated in univariate and multivariate logistic regression analyses., Main Outcome Measures: Birth defects, defined according to the Antiretroviral Pregnancy Registry criteria., Results: A total of 1257 pregnancies with exposure at any time to antiretroviral therapy were evaluated. Forty-two cases with major defects were observed. The total prevalence was 3.2% (95% CI 1.9-4.5) for exposure to any antiretroviral drug during the first trimester (23 cases with defects) and 3.4% (95% CI 1.9-4.9) for no antiretroviral exposure during the first trimester (19 cases). No associations were found between major birth defects and first-trimester exposure to any antiretroviral treatment (OR 0.94, 95% CI 0.51-1.75), main drug classes (nucleoside reverse transcriptase inhibitors, OR 0.95, 95% CI 0.51-1.76; non-nucleoside reverse transcriptase inhibitors, OR 1.20, 95% CI 0.56-2.55; protease inhibitors, OR 0.92, 95% CI 0.43-1.95), and individual drugs, including efavirenz (prevalence for efavirenz, 2.5%)., Conclusions: This study adds further support to the assumption that first-trimester exposure to antiretroviral treatment does not increase the risk of congenital abnormalities., (© 2013 RCOG.)