An Inner Disk in the Large Gap of the Transition Disk SR 24S

We report new Atacama Large Millimeter/sub-millimeter Array (ALMA) Band 3 observations at 2.75 mm of the TD around SR 24S with an angular resolution of $\sim$0.11''$\times$ 0.09'' and a peak signal-to-noise ratio of $\sim24$. We detect an inner disk and a mostly symmetric ring-like structure that peaks at $\sim$0.32'', that is $\sim$37 au at a distance of $\sim$114.4 pc. The full width at half maximum of this ring is $\sim$28 au. We analyze the observed structures by fitting the dust continuum visibilities using different models for the intensity profile, and compare with previous ALMA observations of the same disk at 0.45 mm and 1.30 mm. We qualitatively compare the results of these fits with theoretical predictions of different scenarios for the formation of a cavity or large gap. The comparison of the dust continuum structure between different ALMA bands indicates that photoevaporation and dead zone can be excluded as leading mechanisms for the cavity formation in SR 24S disk, leaving the planet scenario (single or multiple planets) as the most plausible mechanism. We compared the 2.75 mm emission with published (sub-)centimeter data and find that the inner disk is likely tracing dust thermal emission. This implies that any companion in the system should allow dust to move inwards throughout the gap and replenish the inner disk. In the case of one single planet, this puts strong constraints on the mass of the potential planet inside the cavity and the disk viscosity of about $\lesssim$5 $M_{\rm{Jup}}$ and $\alpha\sim10^{-4}-10^{-3}$, respectively.Comment: Accepted to Ap

Probing UV-sensitive Pathways for CN and HCN Formation in Protoplanetary Disks with the Hubble Space Telescope

The UV radiation field is a critical regulator of gas-phase chemistry in surface layers of disks around young stars. In an effort to understand the relationship between photocatalyzing UV radiation fields and gas emission observed at infrared and submillimeter wavelengths, we present an analysis of new and archival Hubble Space Telescope (HST), Spitzer, ALMA, IRAM, and SMA data for five targets in the Lupus cloud complex and 14 systems in Taurus-Auriga. The HST spectra were used to measure Lyα and far-UV (FUV) continuum fluxes reaching the disk surface, which are responsible for dissociating relevant molecular species (e.g., HCN, N₂). Semi-forbidden C II] λ2325 and UV-fluorescent H₂ emission were also measured to constrain inner disk populations of C⁺ and vibrationally excited H2. We find a significant positive correlation between 14 μm HCN emission and fluxes from the FUV continuum and C II] λ2325, consistent with model predictions requiring N₂ photodissociation and carbon ionization to trigger the main CN/HCN formation pathways. We also report significant negative correlations between submillimeter CN emission and both C II] and FUV continuum fluxes, implying that CN is also more readily dissociated in disks with stronger FUV irradiation. No clear relationships are detected between either CN or HCN and Lyα or UV-H₂ emission. This is attributed to the spatial stratification of the various molecular species, which span several vertical layers and radii across the inner and outer disk. We expect that future observations with the James Webb Space Telescope will build on this work by enabling more sensitive IR surveys than were possible with Spitzer

Latitude variation in the prevalence of asthma and allergic rhinitis in Italy: results from the GEIRD study

BACKGROUND: Earlier studies have pointed out a great variability in the prevalence of asthma and asthma-like symptoms in different geo-climatic areas. AIM: To test the association between latitude and prevalence of asthma and allergic rhinitis in Italian young adults. METHODS: In the frame of Gene-Environment Interaction in Respiratory Diseases study, a postal screening questionnaire on respiratory health and exposure to environmental factors was administered to 18,357 randomly selected subjects aged 20-44 years in 7 centres: 3 in Northern (Torino, Pavia, Verona), 2 in Central (Ancona, Perugia) and 2 in Southern Italy (Salerno, Sassari). RESULTS: 10,494 (57.2%) subjects responded to the questionnaire. The prevalence of self-reported doctor-diagnosed asthma and allergic rhinitis in the lifespan was 10.2% and 26.9%, respectively, and was significantly different across the centres (p<0.05). After adjusting for sex, age, potential risk factors for respiratory diseases and design confounders, the prevalence of asthma (OR: 1.07 per 1°latitude decrease, p<0.001), asthma-like symptoms (wheezing, chest tightness, asthma attacks: OR ranging from 1.04 to 1.06, p<0.05) and allergic rhinitis (OR: 1.03, p=0.04) showed a significant north-to-south trend. Similarly, a 1°C increment in temperature was significantly associated with asthma (OR: 1.10, p<0.001) and asthma-like symptoms (OR from 1.07 to 1.10, p<0.05), but not with allergic rhinitis (OR=1.02, p=0.190). CONCLUSION: The prevalence of asthma and allergic rhinitis increased moving southwards in Italy, suggesting that prolonged exposure to different geo-climatic conditions may affect the onset of asthma and allergic respiratory diseases

Probing UV-sensitive Pathways for CN and HCN Formation in Protoplanetary Disks with the Hubble Space Telescope

The UV radiation field is a critical regulator of gas-phase chemistry in surface layers of disks around young stars. In an effort to understand the relationship between photocatalyzing UV radiation fields and gas emission observed at infrared and submillimeter wavelengths, we present an analysis of new and archival Hubble Space Telescope (HST), Spitzer, ALMA, IRAM, and SMA data for five targets in the Lupus cloud complex and 14 systems in Taurus-Auriga. The HST spectra were used to measure Lyα and far-UV (FUV) continuum fluxes reaching the disk surface, which are responsible for dissociating relevant molecular species (e.g., HCN, N₂). Semi-forbidden C II] λ2325 and UV-fluorescent H₂ emission were also measured to constrain inner disk populations of C⁺ and vibrationally excited H2. We find a significant positive correlation between 14 μm HCN emission and fluxes from the FUV continuum and C II] λ2325, consistent with model predictions requiring N₂ photodissociation and carbon ionization to trigger the main CN/HCN formation pathways. We also report significant negative correlations between submillimeter CN emission and both C II] and FUV continuum fluxes, implying that CN is also more readily dissociated in disks with stronger FUV irradiation. No clear relationships are detected between either CN or HCN and Lyα or UV-H₂ emission. This is attributed to the spatial stratification of the various molecular species, which span several vertical layers and radii across the inner and outer disk. We expect that future observations with the James Webb Space Telescope will build on this work by enabling more sensitive IR surveys than were possible with Spitzer

Trends in the prevalence of asthma and allergic rhinitis in Italy between 1991 and 2010

The prevalence of asthma increased worldwide until the 1990s, but since then there has been no clear temporal pattern. The present study aimed to assess time trends in the prevalence of current asthma, asthma-like symptoms and allergic rhinitis in Italian adults from 1990 to 2010. The same screening questionnaire was administered by mail or phone to random samples of the general population (age 20–44 yrs) in Italy, in the frame of three multicentre studies: the European Community Respiratory Health Survey (ECRHS) (1991–1993; n56,031); the Italian Study on Asthma in Young Adults (ISAYA) (1998–2000; n518,873); and the Gene Environment Interactions in Respiratory Diseases (GEIRD) study (2007–2010; n510,494). Time trends in prevalence were estimated using Poisson regression models in the centres that repeated the survey at different points in time. From 1991 to 2010, the median prevalence of current asthma, wheezing and allergic rhinitis increased from 4.1% to 6.6%, from 10.1% to 13.9% and from 16.8% to 25.8%, respectively. The prevalence of current asthma was stable during the 1990s and increased (relative risk 1.38, 95% CI 1.19–1.59) from 1998–2000 to 2007–2010, mainly in subjects who did not report allergic rhinitis. The prevalence of allergic rhinitis has increased continuously since 1991. The asthma epidemic is not over in Italy. During the past 20 yrs, asthma prevalence has increased by 38%, in parallel with a similar increase in asthma-like symptoms and allergic rhiniti

The TW Hya Rosetta Stone Project. I. Radial and Vertical Distributions of DCN and DCO⁺

Molecular D/H ratios are frequently used to probe the chemical past of solar system volatiles. Yet it is unclear which parts of the solar nebula hosted an active deuterium fractionation chemistry. To address this question, we present 0farcs2–0farcs4 Atacama Large Millimeter/submillimeter Array (ALMA) observations of DCO⁺ and DCN 2–1, 3–2, and 4–3 toward the nearby protoplanetary disk around TW Hya, taken as part of the TW Hya Rosetta Stone project, augmented with archival data. DCO⁺ is characterized by an excitation temperature of ~40 K across the 70 au radius pebble disk, indicative of emission from a warm, elevated molecular layer. Tentatively, DCN is present at even higher temperatures. Both DCO⁺ and DCN present substantial emission cavities in the inner disk, while in the outer disk the DCO⁺ and DCN morphologies diverge: most DCN emission originates from a narrow ring peaking around 30 au, with some additional diffuse DCN emission present at larger radii, while DCO⁺ is present in a broad structured ring that extends past the pebble disk. Based on a set of simple parametric disk abundance models, these emission patterns can be explained by a near-constant DCN abundance exterior to the cavity, and an increasing DCO⁺ abundance with radius. In conclusion, the ALMA observations reveal an active deuterium fractionation chemistry in multiple disk regions around TW Hya, but not in the cold planetesimal-forming midplane and in the inner disk. More observations are needed to explore whether deuterium fractionation is actually absent in these latter regions, and if its absence is a common feature or something peculiar to the old TW Hya disk

The TW Hya Rosetta Stone Project. II. Spatially Resolved Emission of Formaldehyde Hints at Low-temperature Gas-phase Formation

Formaldehyde (H₂CO) is an important precursor to organics like methanol (CH₃OH). It is important to understand the conditions that produce H₂CO and prebiotic molecules during star and planet formation. H₂CO possesses both gas-phase and solid-state formation pathways, involving either UV-produced radical precursors or CO ice and cold ( 20 K) dust grains. To understand which pathway dominates, gaseous H₂CO's ortho-to-para ratio (OPR) has been used as a probe, with a value of 3 indicating "warm" conditions and <3 linked to cold formation in the solid state. We present spatially resolved Atacama Large Millimeter/submillimeter Array observations of multiple ortho- and para-H₂CO transitions in the TW Hya protoplanetary disk to test H₂CO formation theories during planet formation. We find disk-averaged rotational temperatures and column densities of 33 ± 2 K, (1.1 ± 0.1) × 10¹² cm⁻² and 25 ± 2 K, (4.4 ± 0.3) × 10¹¹ cm⁻² for ortho- and para-H₂CO, respectively, and an OPR of 2.49 ± 0.23. A radially resolved analysis shows that the observed H₂CO emits mostly at rotational temperatures of 30–40 K, corresponding to a layer with z/R ≥ 0.25. The OPR is consistent with 3 within 60 au, the extent of the pebble disk, and decreases beyond 60 au to 2.0 ± 0.5. The latter corresponds to a spin temperature of 12 K, well below the rotational temperature. The combination of relatively uniform emitting conditions, a radial gradient in the OPR, and recent laboratory experiments and theory on OPR ratios after sublimation, led us to speculate that gas-phase formation is responsible for the observed H₂CO across the TW Hya disk