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To assess whether patient age is independently associated to Intensive Care Unit (ICU) admission after non-cardiac surgery.

Spectral observations of Neptune made in 2019 with the Multi Unit Spectroscopic Explorer (MUSE) instrument at the Very Large Telescope (VLT) in Chile have been analyzed to determine the spatial variation of aerosol scattering properties and methane abundance in Neptune's atmosphere. The darkening of the South Polar Wave at ∼60°S, and dark spots such as the Voyager 2 Great Dark Spot is concluded to be due to a spectrally dependent darkening (λ< 650 nm) of particles in a deep aerosol layer at ∼5 bar and presumed to be composed of a mixture of photochemically generated haze and H2S ice. We also note a regular latitudinal variation of reflectivity at wavelengths of very low methane absorption longer than ∼650 nm, with bright zones latitudinally separated by ∼25°. This feature, which has similar spectral characteristics to a discrete deep bright spot DBS‐2019 found in our data, is found to be consistent with a brightening of the particles in the same ∼5‐bar aerosol layer at λ> 650 nm. We find the properties of an overlying methane/haze aerosol layer at ∼2 bar are, to first‐order, invariant with latitude, while variations in the opacity of an upper tropospheric haze layer reproduce the observed reflectivity at methane‐absorbing wavelengths, with higher abundances found at the equator and also in a narrow “zone” at 80°S. Finally, we find the mean abundance of methane below its condensation level to be 6%–7% at the equator reducing to ∼3% south of ∼25°S, although the absolute abundances are model dependent. Observations of Neptune in visible light, made with the Multi Unit Spectroscopic Explorer (MUSE) instrument at ESO's Very Large Telescope, reveal the different layers of clouds and gases within this Ice Giant atmosphere, and how they change with height and latitude. The properties of the 1–2‐bar layer of methane ice and haze are found to be roughly constant with latitude. However, a diffuse upper layer is thickest at the equator and near the south pole, indicating air rising at mid‐latitudes and descending near the equator and poles. Conversely, the distribution of methane between the deep 5‐bar clouds (hydrogen sulphide ice and haze) and the middle layers decreases from 6% to 7% at the equator to ∼3% near the south pole, suggesting instead that air is rising at the equator and descending elsewhere. Finally, a blue‐green darkening of the particles in the deep layer can explain Neptune's dark spots and the dark “South Polar Wave” at 60°S, whereas a brightening of the same particles at red and infrared wavelengths matches occasional discrete deep bright spots and a set of previously unnoticed bright “zones”, separated by 25° latitude. All this is evidence that the atmospheric circulation changes as a function of height and latitude in complex and surprising ways. Neptune Multi Unit Spectroscopic Explorer (MUSE) visible/near‐infrared spectra are well fitted by a simple aerosol model comprised of three distinct layersA darkening of particles at blue‐green wavelengths in a deep aerosol layer near 5 bar can explain dark spots and the dark “South Polar Wave”A brightening of the same particles at red‐infrared wavelengths can explain bright zones and spots seen in longwave narrow reflectance peaks Neptune Multi Unit Spectroscopic Explorer (MUSE) visible/near‐infrared spectra are well fitted by a simple aerosol model comprised of three distinct layers A darkening of particles at blue‐green wavelengths in a deep aerosol layer near 5 bar can explain dark spots and the dark “South Polar Wave” A brightening of the same particles at red‐infrared wavelengths can explain bright zones and spots seen in longwave narrow reflectance peaks

One of the most intriguing, long‐standing questions regarding Venus's atmosphere is the origin and distribution of the unknown UV absorber, responsible for the absorption band detected at the near‐UV and blue range of Venus's spectrum. In this work, we use data collected by Mercury Atmospheric and Surface Composition Spectrometer (MASCS) spectrograph on board the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission during its second Venus flyby in June 2007 to address this issue. Spectra range from 0.3 μm to 1.5 μm including some gaseous H2O and CO2bands, as well as part of the SO2absorption band and the core of the UV absorption. We used the NEMESIS radiative transfer code and retrieval suite to investigate the vertical distribution of particles in the equatorial atmosphere and to retrieve the imaginary refractive indices of the UV absorber, assumed to be well mixed with Venus's small mode 1 particles. The results show a homogeneous equatorial atmosphere, with cloud tops (height for unity optical depth) at 75 ± 2 km above surface. The UV absorption is found to be centered at 0.34 ± 0.03 μm with a full width at half maximum of 0.14 ± 0.01 μm. Our values are compared with previous candidates for the UV aerosol absorber, among which disulfur oxide (S2O) and dioxide disulfur (S2O2) provide the best agreement with our results. The atmosphere of Venus is fully cloud covered, and its clouds are very reflective in most visual wavelengths, with the exception of the near ultraviolet, where an absorber of unknown origin strongly absorbs solar radiation. Such a mysterious absorber provides contrast to many atmospheric features whose dynamics can be tracked from images, and it also has a substantial role in the energy budget of the planet. But, as of today, we have no clear idea what it is made of. In this work, we have analyzed spectra taken during the second Venus flyby of MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft on its route to Mercury, in 2007. Using a numerical code, we have reproduced the light reflected by the equatorial atmosphere of the planet and retrieved the distribution of particles in the upper atmosphere of Venus, with a cloud top of some 75 km above the surface. We have also retrieved the absorption spectrum of the puzzling absorber and compared it with some previously proposed candidates. While no perfect match is found, sulfur‐bearing species (S2O and S2O2) provide the best agreement. There is still a long way to undoubtedly identify Venus's UV absorber, but this work provides substantial spectral constraints. We analyze spectra of Venus's equatorial atmosphere taken during the second MESSENGER flyby on 5 June 2007Cloud tops are located at 75 ± 2 km in the equatorial atmosphere.Among all candidates proposed so far, S2O and S2O2, with subindices provide the best agreement with the UV absorption retrieved here

Haumea—one of the four known trans-Neptunian dwarf planets—is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo’s rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea’s equator and the orbit of its satellite Hi’iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea’s spin period—that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea’s largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

We describe a huge planetary‐scale disturbance in the highest‐speed Jovian jet at latitude 23.5°N that was first observed in October 2016 during the Juno perijove‐2 approach. An extraordinary outburst of four plumes was involved in the disturbance development. They were located in the range of planetographic latitudes from 22.2° to 23.0°N and moved faster than the jet peak with eastward velocities in the range 155 to 175 m s−1. In the wake of the plumes, a turbulent pattern of bright and dark spots (wave number 20–25) formed and progressed during October and November on both sides of the jet, moving with speeds in the range 100–125 m s−1and leading to a new reddish and homogeneous belt when activity ceased in late November. Nonlinear numerical models reproduce the disturbance cloud patterns as a result of the interaction between local sources (the plumes) and the zonal eastward jet. A planetary‐scale disturbance developed in the highest‐speed Jupiter jet at 23.5°N latitude during October and November 2016Four “plumes” were involved in the outbreak moving with speeds between 155 and 175 m s−1, the fastest features at cloud levelNonlinear numerical models reproduce the disturbance from the interaction between local sources (the plumes) and the zonal eastward jet

We analyze Jupiter observations between December 2015 and August 2016 in the 0.38–1.7 μm wavelength range from the PlanetCam instrument at the 2.2 m telescope at Calar Alto Observatory and in the optical range by amateur observers contributing to the Planetary Virtual Observatory Laboratory. Over this time Jupiter was in a quiescent state without notable disturbances. Analysis of ground‐based images and Hubble Space Telescope observations in February 2016 allowed the retrieval of mean zonal winds from −74.5° to +73.2°. These winds did not change over 2016 or when compared with winds from previous years with the sole exception of intense zonal winds at the North Temperate Belt. We also present results concerning the major wave systems in the North Equatorial Belt and in the upper polar hazes visible in methane absorption bands, a description of the planet's overall cloud morphology and observations of Jupiter hours before Juno's orbit insertion. We present a characterization of Jupiter clouds and their dynamics prior to Juno's arrival. We present results based on observations with our own high‐resolution instrument PlanetCam, Hubble Space Telescope images acquired in February 2016, and analysis of high‐quality images provided by amateur astronomers using small telescopes. Before Juno's arrival to Jupiter its atmosphere behaved in a normal way without major convective outbreaks or changes in its usual belts and bands. Juno's first perijove characterized Jupiter at a time of usual behavior of the planet. Zonal winds were similar to previous years except for high values of the wind velocity at the most intense jet stream in the planet in the North Temperate latitudes which reached values of 157 m/s. We also study two systems of planetary‐scale waves in the planet: The first system is north to the equator in the North Equatorial Belt and is characterized by a regular pattern of large dark features in the planet. These are regions of reduced cloud content formed by an atmospheric wave. The second system is an undulatory pattern in the polar hazes that is best observed in the southern hemisphere. Both are characterized for later comparisons with results from the Juno mission. We present the overall cloud morphology of Jupiter over 2016 from images in the spectral range 0.38–1.7 micrometersWe characterize the equatorial hot spots and present snapshots of the polar regions providing context for observations from JunoWe measured zonal winds from December 2015 to June 2016 spanning the latitude range 74.5°S–73.2°N without variability over this period

Aims. Despite the banded visual aspect of cloud patterns in Jupiter, high resolution images indicate that these regions are markedly turbulent. One region of particular interest is the north temperate belt (NTB) at 21° N planetocentric latitude, where the most intense Jovian jet resides with eastward peak speeds of 160-180 m s-1. Almost every 15 years, the NTB is known to experience an eruption or disturbance that dramatically changes its appearance, a phenomenon known as NTB disturbance (NTBD). In this work, we characterize the morphology of the disturbed cloud field in the wake of the plumes that caused the perturbation, and check for changes in the velocity or shape of the jet.

Aims.The main goal of this paper is to study the reflectivity changes that affect Saturn's global belt/zone pattern on time-scales from weeks to a few months, and to determine their frequency and intensity, as well as the variations of the vertical cloud structure that cause such changes.

We investigate the long‐term motion of Saturn's north pole hexagon and the structure of its associated eastward jet, using Cassini imaging science system and ground‐based images from 2008 to 2014. We show that both are persistent features that have survived the long polar night, the jet profile remaining essentially unchanged. During those years, the hexagon vertices showed a steady rotation period of 10 h 39 min 23.01 ± 0.01 s. The analysis of Voyager 1 and 2 (1980–1981) and Hubble Space Telescope and ground‐based (1990–1991) images shows a period shorter by 3.5 s due to the presence at the time of a large anticyclone. We interpret the hexagon as a manifestation of a vertically trapped Rossby wave on the polar jet and, because of their survival and unchanged properties under the strong seasonal variations in insolation, we propose that both hexagon and jet are deep‐rooted atmospheric features that could reveal the true rotation of the planet Saturn. Hexagon wave steady motionJet stream unchanged to seasonal changesSaturn's rotation

We present a reanalysis (using the Minnaert limb‐darkening approximation) of visible/near‐infrared (0.3–2.5 μm) observations of Uranus and Neptune made by several instruments. We find a common model of the vertical aerosol distribution i.e., consistent with the observed reflectivity spectra of both planets, consisting of: (a) a deep aerosol layer with a base pressure >5–7 bar, assumed to be composed of a mixture of H2S ice and photochemical haze; (b) a layer of photochemical haze/ice, coincident with a layer of high static stability at the methane condensation level at 1–2 bar; and (c) an extended layer of photochemical haze, likely mostly of the same composition as the 1–2‐bar layer, extending from this level up through to the stratosphere, where the photochemical haze particles are thought to be produced. For Neptune, we find that we also need to add a thin layer of micron‐sized methane ice particles at ∼0.2 bar to explain the enhanced reflection at longer methane‐absorbing wavelengths. We suggest that methane condensing onto the haze particles at the base of the 1–2‐bar aerosol layer forms ice/haze particles that grow very quickly to large size and immediately “snow out” (as predicted by Carlson et al. (1988), https://doi.org/10.1175/1520-0469(1988)045<2066:CMOTGP>2.0.CO;2), re‐evaporating at deeper levels to release their core haze particles to act as condensation nuclei for H2S ice formation. In addition, we find that the spectral characteristics of “dark spots”, such as the Voyager‐2/ISS Great Dark Spot and the HST/WFC3 NDS‐2018, are well modelled by a darkening or possibly clearing of the deep aerosol layer only. Previous studies of the reflectance spectra of Uranus and Neptune have concentrated on individual, narrow wavelength regions and the conclusions have been difficult to compare with each other. Here, we analyse a combined set of observations from three different instruments covering the wavelength range 0.3–2.5 μm to arrive at a singleaerosol model that matches the observations at all wavelengths simultaneously for bothplanets. We conclude that photochemical haze produced in the upper atmospheres of both planets is steadily mixed down to lower layers, where it forms part of a vertically thin layer in a statically stable region above the methane condensation level at 1–2 bar. We suggest that methane condenses so rapidly upon these haze particles that it efficiently “snows” out at the base of this layer, falling to lower, warmer levels, where the methane evaporates, releasing the core haze particles to “seed” H2S condensation. For Neptune we need to add an additional layer of moderately large methane ice particles at ∼0.2 bar. Intriguingly, we find that a darkening (or perhaps clearing) of the lowest H2S/haze layer matches very well the observed properties of the dark spots seen occasionally in Neptune's atmosphere and very occasionally in Uranus's atmosphere. Ice Giant reflectivity spectra from 0.3 to 2.5 μm well approximated by a single aerosol model comprised of three to four distinct layersStatic stability region at 1–2 bar, caused by methane condensation, seems to lead to build‐up of haze and seeds CH4snow at its baseDarkening of deepest H2S/haze layer, based at p> 5–7 bar, found to account well for spectral properties of dark spots Ice Giant reflectivity spectra from 0.3 to 2.5 μm well approximated by a single aerosol model comprised of three to four distinct layers Static stability region at 1–2 bar, caused by methane condensation, seems to lead to build‐up of haze and seeds CH4snow at its base Darkening of deepest H2S/haze layer, based at p> 5–7 bar, found to account well for spectral properties of dark spots

Saturn’s Great White Spots are rare planetary-scale storms that have been observed only six times since 1876. The most recent Great White Spot appeared in December 2010 and has been studied from both ground-based and spacecraft observations. The storm developed into an enormous disturbance extending over 10,000?km at cloud level, emitted intense electrostatic discharges over several months, and caused long-standing localized warming in the high stratosphere of about 60?K. Here we analyse the dynamics of the storm’s head using high-resolution imagery obtained by the Cassini spacecraft on 26 February 2011. We find strong winds with speeds up to 160?m?s-1and organized into a divergent open anticyclone where massive cumulus-like cloud clusters interact with the ambient zonal flow to generate a storm front. The cloud clusters evolved over a timescale of hours, with cloud tops reaching 44?km above the undisturbed environment. Simulations using a general circulation model, which includes Saturn’s zonal winds, reproduce the observations when a persistent heat source is introduced, causing a high-pressure anomaly. We conclude that the complex phenomenology of a mature Great White Spot represents a natural response of the saturnian atmosphere to severe sustained convection in a sheared background flow.

STUDY OBJECTIVE: The objective of this paper is to introduce a different approach, called the ecological-longitudinal, to carrying out pooled analysis in time series ecological studies. Because it gives a larger number of data points and, hence, increases the statistical power of the analysis, this approach, unlike conventional ones, allows the complementation of aspects such as accommodation of random effect models, of lags, of interaction between pollutants and between pollutants and meteorological variables, that are hardly implemented in conventional approaches. DESIGN: The approach is illustrated by providing quantitative estimates of the short-term effects of air pollution on mortality in three Spanish cities, Barcelona, Valencia and Vigo, for the period 1992-1994. Because the dependent variable was a count, a Poisson generalised linear model was first specified. Several modelling issues are worth mentioning. Firstly, because the relations between mortality and explanatory variables were non-linear, cubic splines were used for covariate control, leading to a generalised additive model, GAM. Secondly, the effects of the predictors on the response were allowed to occur with some lag. Thirdly, the residual autocorrelation, because of imperfect control, was controlled for by means of an autoregressive Poisson GAM. Finally, the longitudinal design demanded the consideration of the existence of individual heterogeneity, requiring the consideration of mixed models. MAIN RESULTS: The estimates of the relative risks obtained from the individual analyses varied across cities, particularly those associated with sulphur dioxide. The highest relative risks corresponded to black smoke in Valencia. These estimates were higher than those obtained from the ecological-longitudinal analysis. Relative risks estimated from this latter analysis were practically identical across cities, 1.00638 (95% confidence intervals 1.0002, 1.0011) for a black smoke increase of 10 μg/m³ and 1.00415 (95% CI 1.0001, 1.0007) for a increase of 10 μg/m³ of sulphur dioxide. Because the statistical power is higher than in the individual analysis more interactions were statistically significant, especially those among air pollutants and meteorological variables. CONCLUSIONS: Air pollutant levels were related to mortality in the three cities of the study, Barcelona, Valencia and Vigo. These results were consistent with similar studies in other cities, with other multicentric studies and coherent with both, previous individual, for each city, and multicentric studies for all three cities.

The objective of the study was to determine whether measures taken to prevent human immunodeficiency virus (HIV) infection also lead to a reduction in the prevalence of hepatitis C virus (HCV) infection among intravenous drug users (IDU). Antibodies to HCV, HIV and hepatitis B virus (HBV) were determined in IDU who voluntarily attended AIDS prevention and information centres for the first time between 1990 and 1996. Of the 5473 IDU studied, determination of HCV was done in 3238 cases. The prevalence of antibodies to HCV was 85%. During the first period studied (1990–1992), the prevalence of antibodies to HCV was 84.5%, during the second (1993–1994) 84.1% and during the third (1995–1996) 87%; in the case of HBV the prevalence during the three periods was 74.5, 67.6 and 66.8% respectively, and for HIV it was 41.9, 38.8 and 36.6% respectively (RR: 0.72; 95% confidence interval (CI): 0.65–0.81). Among drug users addicted for less than 2 years, the trend of the prevalence of antibodies to HCV and HBV remained constant, while the prevalence of HIV infection decreased (RR: 0.61; 95% CI: 0.42–0.89). Measures to prevent transmission of HIV in drug users do not lead to a reduction in the prevalence of HCV infection. Further study is necessary to obtain a better understanding of how HCV is transmitted among drug users in order to apply measures which are effective in preventing HCV infection.

STUDY OBJECTIVE: To estimate the short-term association between air pollution levels and emergency hospital admissions for cardiovascular diseases in Valencia, within 1994-1996 period. DESIGN: Daily levels of air pollution and emergency admissions for cardiovascular diseases were related to using an ecological time series design. The number of admissions was obtained from the hospital records database. Selected groups of causes were all cardiovascular diseases, heart admissions, and admissions for cerebrovascular diseases. The number of admissions for digestive diseases was used as control. Pollutants were black smoke, sulphur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO) and ozone (O₃). Magnitude of association was estimated by Poisson autoregresive regression. Estimations were calculated according the hottest (May to October) and the coldest (November to April) periods. SETTING: City of Valencia, Spain, about 750 000 inhabitants. PARTICIPANTS: People being admitted to the two major hospitals in the city, with a catchment area of nearly 400 000 inhabitants. MAIN RESULTS: For the whole period, a significant association for SO₂-24 h was found so a rise in its levels of 10 μg/m³ was associated with an increment of 3% (95%CI 0.4 to 5.7%) in the expected number of cardiovascular admissions. A significant association for black smoke, SO₂-24 h, SO₂-1 h, and CO-1 h was found in the hottest semester. All these associations were verified with a lag of two days. The estimates of the associations for particles, SO₂, and CO were affected by the inclusion of the other pollutants in their models. NO₂ was independently associated with cerebrovascular admissions. There were no significant associations between air pollution and admissions for digestive diseases. CONCLUSIONS: Current levels of air pollution and emergency cardiovascular admissions are significantly related in Valencia.

The aim of this paper is to model the length of stay following hospital emergency due to asthma and chronic obstructive pulmonary disease (COPD) as well as those factors relating to its duration. Clinical records of all those hospital emergencies for asthma and COPD in people aged over 14 at the Hospital Clinico Universitario of Valencia (HCUV) during years 1993–1995 were reviewed. Data were analysed by entry and discharge time, sex, age and destination. Parametric survival models (exponential, Weibull and log-normal) were used for each diagnostic. Percentiles and relative percentiles were calculated; 1369 asthma emergencies and 2734 cases COPD were observed. The mean length of stay was 5.21 hours for asthma and 6.32 for COPD log-normal model was the best parametric model. Lengths of stay are greater for those hospital admitted. Stays, in cases of asthma, were shorter during months of August and November, with no differences for other variables. Also a shorter duration of stay for the month of August was found. Women are seen to stay for longer periods than men. Time modelling of emergency admission for asthma and COPD permits its use in the determining of the dates of incidence for episodes of asthma and COPD based on hospital admissions data, as seeing a median of delay in emergency rooms greater than 6 hours. For studies on air pollution impact these results imply that all those admissions during the early hours of the morning should be categorised as events of the previous day.

The atmosphere of Mars presents a strong response to aerosol radiative forcing compared to that of the Earth, thus atmospheric models should have accurate radiative transfer algorithms for the simulation of temperatures and circulation. In this work, we evaluate the radiative effects of dust aerosol calculated by different radiative transfer schemes and the influence of dust properties in these calculations. Two‐stream solutions were compared with multistream discrete ordinate methods. Fluxes and heating rates were evaluated for a variety of atmospheric conditions, including dust storms. The results show that in low‐to‐medium dust opacity scenarios, the highly efficient two‐stream methods provide accurate estimations, with heating rate errors of less than 2 K/sol. These errors increase with opacity, when differences of 20 K/sol are reached, which may be relevant in the simulations of temperature fields and atmospheric circulation under regional and global dust storm conditions. In such cases, the use of four‐stream or higher order methods may be required, although accuracy improvements for eight‐ or higher‐stream schemes were negligible. The influence of dust particle properties in aerosol radiative forcing estimations is mainly due to the particle size, where variations of 20% of the effective radius resulted in differences of 5 K/sol; the shape of the particles showed a minor impact, with differences of <2 K/sol. The results of this study contribute to quantification of the uncertainties in current Mars climate models and may help modellers to select the appropriate approach depending on the scenario. The thin atmosphere of Mars has a strong response to the effects of dust aerosol compared to that of the Earth. The radiative heating and cooling due to dust affect the temperatures and drive the Martian climate at all spatial scales. In addition, remote sensing retrievals and studies of climate and weather on Mars depend on precise calculations of these quantities. The “two‐stream” method for calculating the energy budget and temperature variations is widely used, although it presents some limitations in modeling dust interactions with solar radiation. In this work, we compare radiative estimations of this method with results obtained by more accurate, but time consuming, algorithms. The comparison results show a good agreement when there is low to medium amount of lofted dust. As the atmospheric dust loading increases, such as in the case of regular Mars dust storms, more complex methods may be required. Regarding the influence of dust particle properties in these calculations, the uncertainties associated with the size of the particles introduce meaningful differences at high altitudes. The results of this study contribute to quantification of the uncertainties in Mars climate models and may help modellers to select the appropriate method depending on the scenario. We study the accuracy and performance of radiative transfer schemes of Mars' atmosphere and the impact of dust aerosol particle propertiesTwo‐stream approximations provide accurate radiative flux and heating rate estimates in low and medium opacity scenariosIn high opacity cases and dust storms, four‐stream methods may be recommended. Accuracy improvements from higher‐order methods are negligible We study the accuracy and performance of radiative transfer schemes of Mars' atmosphere and the impact of dust aerosol particle properties Two‐stream approximations provide accurate radiative flux and heating rate estimates in low and medium opacity scenarios In high opacity cases and dust storms, four‐stream methods may be recommended. Accuracy improvements from higher‐order methods are negligible

Evaluation of acquired immunodeficiency syndrome (AIDS) prevention strategies requires an on-going follow up of the frequency of human immunodeficiency virus (HIV-1) infection. The aim of this study was to examine the trends in prevalence and incidence of HIV-1 infection among injecting drug users (IDU) during the period 1987-1996.

To assess the short term relationship between daily air pollution indicators (black smoke and sulphur dioxide (SO2)) and mortality in Valencia.

Increased mortality is associated with both very low and very high ambient temperatures. This study assesses the relationship between daily numbers of deaths and variations in ambient temperature within the city of Valencia.

Jupiter’s Great Red Spot (GRS), a giant anticyclone, is the largest and longest‐lived of all the vortices observed in planetary atmospheres. During its history, the GRS has shrunk to half its size since 1879, and encountered many smaller anticyclones and other dynamical features that interacted in a complex way. In 2018–2020, while having a historically small size, its structure and even its survival appeared to be threatened when a series of anticyclones moving in from the east tore off large fragments of the red area and distorted its shape. In this work, we report observations of the dynamics of these interactions and show that as a result the GRS increased its internal rotation velocity, maintaining its vorticity but decreasing its visible area, and suffering a transient change in its otherwise steady 90‐day oscillation in longitude. From a radiative transfer analysis and numerical simulations of the dynamics we show that the interactions affected the upper cloud tops of the GRS. We argue that the intense vorticity of the GRS, together with its larger size and depth compared to the interacting vortices, guarantees its long lifetime. Jupiter’s Great Red Spot (GRS) is a giant anticyclone with a length that has shrunk since 1879 from ∼ 40,000 km to its current value of 15,000 km. The GRS is the longest‐lived of all the planetary vortices, observed perhaps since the 17th century. During its history, the GRS has encountered a variety of smaller anticyclones and other dynamical features, surviving these interactions. In 2018–2020, a series of anticyclones interacted with it, and tore off large fragments of its red area (called “flakes”), eroding and distorting its oval shape, and apparently threatening its survival. The interactions produced an increase in the GRS internal rotation velocity accompanied by a transient increase in the period and amplitude of its steady 90‐day oscillation in longitude. From the analysis of the reflectivity of the GRS and flakes and model simulations of the dynamics of the interactions we find that these events are likely to have been superficial, not affecting the full depth of the GRS. The interactions are not necessarily destructive but can transfer energy to the GRS, maintaining it in a steady state and guaranteeing its long lifetime. In 2018–2020, Jupiter’s Great Red Spot interacted with series of anticyclones, losing part of its visible red area and distorting its shapeThe Great Red Spot (GRS) increased its tangential velocity; it did not change its vorticity, but did temporarily change its 90‐day oscillation in longitudeDynamical and radiative transfer modeling shows that the interactions affected the upper cloud of the GRS with no risk for its survival In 2018–2020, Jupiter’s Great Red Spot interacted with series of anticyclones, losing part of its visible red area and distorting its shape The Great Red Spot (GRS) increased its tangential velocity; it did not change its vorticity, but did temporarily change its 90‐day oscillation in longitude Dynamical and radiative transfer modeling shows that the interactions affected the upper cloud of the GRS with no risk for its survival

Background. In order to identify, in a sample of heroin intravenous drug users (IVDU), those factors associated with the predominant risk behaviour related to the transmission of HIV-1 infection-sharing of Injection equipment-a cross-sectional survey was carried out In Valencla, Spain from 1987 to 1992. Methods. Informed consent and pertinent data were obtained from 3755 heroin IVDU recruited at two public AIDS Information Centres in two cities in the region of Valencla. Data were gathered on soclodemographic variables, and sexual and drug use behaviour by interview. The subjects were subsequently tested for HIV-1 antibody. A univanate analysis was carried out to identify variables that were significantly associated with sharing Injection equipment. A logistic regression model was used to control for possible confounders. Results. The IVDU who were teenagers, prostitutes (OR = 1.95), who had antibodies to HIV-1 (OR = 1.30) or who had an IVDU steady partner were at significantly higher risk for sharing of injection equipmenl Higher levels of education, condom use (OR = 0.65) and lMng In the smaller city (OR = 0.75) were inversely related to sharing injection equipment. Conclusions. Our results suggest that different subgroups of IVDU have different characteristics that place them at different risk for HIV-1 infection. These characteristics should guide the design and intensity of specific preventive interventions. Teenagers and IVDU with low educational levels should be targetted for special attention by health authorities.