138 research outputs found

    ALMA Observations of the Young Substellar Binary System 2M1207

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    We present ALMA observations of the 2M1207 system, a young binary made of a brown dwarf with a planetary-mass companion at a projected separation of about 40 au. We detect emission from dust continuum at 0.89 mm and from the J=3−2J = 3 - 2 rotational transition of CO from a very compact disk around the young brown dwarf. The small radius found for this brown dwarf disk may be due to truncation from the tidal interaction with the planetary-mass companion. Under the assumption of optically thin dust emission, we estimated a dust mass of 0.1 M⊕M_{\oplus} for the 2M1207A disk, and a 3σ\sigma upper limit of ∌1 MMoon\sim 1~M_{\rm{Moon}} for dust surrounding 2M1207b, which is the tightest upper limit obtained so far for the mass of dust particles surrounding a young planetary-mass companion. We discuss the impact of this and other non-detections of young planetary-mass companions for models of planet formation, which predict the presence of circum-planetary material surrounding these objects.Comment: 10 pages, 6 figures, accepted for publication in A

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

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    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

    Chronic bronchitis without airflow obstruction, asthma and rhinitis are differently associated with cardiovascular risk factors and diseases

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    Cardiovascular and respiratory diseases can frequently coexist. Understanding their link may improve disease management. We aimed at assessing the associations of chronic bronchitis (CB), asthma and rhinitis with cardiovascular diseases and risk factors in the general population

    ALMA observations of the young substellar binary system 2M1207

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    Funding: J.M.C. acknowledges support from the National Aeronautics and Space Administration under Grant No. 15XRP15_20140 issued through the Exoplanets Research Program. Support for this work was provided by NASA through Hubble Fellowship grant HST-HF2-51369.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555.We present ALMA observations of the 2M1207 system, a young binary made of a brown dwarf with a planetary-mass companion at a projected separation of about 40 au. We detect emission from dust continuum at 0.89 mm and from the J=3-2 rotational transition of CO from a very compact disk around the young brown dwarf. The small radius found for this brown dwarf disk may be due to truncation from the tidal interaction with the planetary-mass companion. Under the assumption of optically thin dust emission, we estimate a dust mass of 0.1 M ⊕ for the 2M1207A disk and a 3σ upper limit of ∌1 MMoon for dust surrounding 2M1207b, which is the tightest upper limit obtained so far for the mass of dust particles surrounding a young planetary-mass companion. We discuss the impact of this and other non-detections of young planetary-mass companions for models of planet formation that predict circumplanetary material to surround these objects.Publisher PDFPeer reviewe

    The ALMA Lupus protoplanetary disk survey: Evidence for compact gas disks and molecular rings from CN

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    The cyanide radical CN is abundant in protoplanetary disks, with line fluxes often comparable to those of 13CO. It is known to be sensitive to UV irradiation of the upper disk atmosphere, with models predicting ring-shaped emission. Aims. We seek to characterize the CN emission from 94 Class-II disks in the Lupus star-forming region, compare it to observations in other regions, and interpret our observations with a grid of models. The CN emission morphology is discussed for two primordial disks, Sz 71 and Sz 98, and is modeled in more detail. Methods. ALMA observed CN N = 32 in Lupus disks down to sensitivities better than previous surveys. Models constructed with the physico-chemical code DALI are used to study the integrated fluxes of the disks and resolved emission of CN in disks without (dust) substructures. Results. CN N = 32 is bright, and detected in 38% of sources, but its disk-integrated flux is not strongly correlated to either 13CO or continuum flux. Compared to pre-ALMA single-dish surveys, no significant difference in the CN flux distributions in Lupus and Taurus-Auriga is found, although Ophiuchus disks may be fainter on average. We find ring-shaped CN emission with peak radii of 50AU in two resolved disks. Conclusions. A large fraction of sources are faint in CN; only exponential gas surface density cutoffs at Rc 15AU can reconcile observations with models. This is the first observational evidence of such a compact gas disk population in Lupus. bsolute intensities and the emission morphology of CN are reproduced by DALI models without the need for any continuum substructure; they are unrelated to the CO snowline location. The observations presented here, together with the modeling of these rings, provide a new probe of the structure and conditions in disks, and particularly their incident UV radiation field, if disk size is determined from the data

    The ALMA Lupus protoplanetary disk survey: Evidence for compact gas disks and molecular rings from CN

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    The cyanide radical CN is abundant in protoplanetary disks, with line fluxes often comparable to those of 13CO. It is known to be sensitive to UV irradiation of the upper disk atmosphere, with models predicting ring-shaped emission. Aims. We seek to characterize the CN emission from 94 Class-II disks in the Lupus star-forming region, compare it to observations in other regions, and interpret our observations with a grid of models. The CN emission morphology is discussed for two primordial disks, Sz 71 and Sz 98, and is modeled in more detail. Methods. ALMA observed CN N = 32 in Lupus disks down to sensitivities better than previous surveys. Models constructed with the physico-chemical code DALI are used to study the integrated fluxes of the disks and resolved emission of CN in disks without (dust) substructures. Results. CN N = 32 is bright, and detected in 38% of sources, but its disk-integrated flux is not strongly correlated to either 13CO or continuum flux. Compared to pre-ALMA single-dish surveys, no significant difference in the CN flux distributions in Lupus and Taurus-Auriga is found, although Ophiuchus disks may be fainter on average. We find ring-shaped CN emission with peak radii of 50AU in two resolved disks. Conclusions. A large fraction of sources are faint in CN; only exponential gas surface density cutoffs at Rc 15AU can reconcile observations with models. This is the first observational evidence of such a compact gas disk population in Lupus. bsolute intensities and the emission morphology of CN are reproduced by DALI models without the need for any continuum substructure; they are unrelated to the CO snowline location. The observations presented here, together with the modeling of these rings, provide a new probe of the structure and conditions in disks, and particularly their incident UV radiation field, if disk size is determined from the data

    Changes in the use of anti-asthmatic medication in an international cohort

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldThe aim of this study was to describe changes in pharmacotherapy for asthma since the early 1990s in an international cohort of young and middle-aged adults. A total of 28 centres from 14 countries participated in a longitudinal study. The study included 8,829 subjects with a mean follow-up time of 8.7 yrs. Change in the prevalence of use for medication was expressed as absolute net change (95% confidence interval) standardised to a 10-yr period. The use of anti-asthmatics was found to have increased by 3.1% (2.4-3.7%) and the prevalence of symptomatic asthma by 4.0% (3.5-4.5%). In the sample with asthma in both surveys (n=423), the use of inhaled corticosteroids increased by 12.2% (6.6-17.8%). Despite this, only 17.2% were using inhaled corticosteroids on a daily basis at follow-up. Females with continuous asthma were more likely, compared with males, and smokers with asthma, to have started using inhaled corticosteroids since the first survey. The use of anti-asthmatics has increased in a pattern consistent with current consensus on treatment. However, despite increased use of inhaled corticosteroids, a large majority of subjects with symptomatic asthma do not use this treatment on a daily basis, particularly males and smokers with asthma

    High gas-to-dust size ratio indicating efficient radial drift in the mm-faint CX Tauri disk

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    The large majority of protoplanetary disks have very compact (â‰Č15 \lesssim15\,AU) continuum emission at mm wavelengths. However, high angular resolution observations that resolve these small disks are still lacking, due to their intrinsically fainter emission compared with large bright disks. In this letter, we present 1.3 1.3\,mm ALMA data of the faint (∌10 \sim10\,mJy) disk orbiting the TTauri star CX Tau at a resolution of ∌40 \sim40\,mas, ∌5 \sim5\,AU in diameter. The mm-dust disk is compact, with a 68%\% enclosing flux radius of 14 \,AU, and the intensity profile exhibits a sharp drop between 10-20 \,AU, and a shallow tail between 20-40 \,AU. No clear signatures of substructure in the dust continuum are observed, down to the same sensitivity level of the DSHARP large program. However, the angular resolution does not allow to detect substructures at a scale of the disk aspect ratio in the inner regions. The radial intensity profile resembles well the inner regions of more extended disks imaged at the same resolution in DSHARP, but with no rings present in the outer disk. No inner cavity is detected, even though the disk has been classified as a transition disk from the spectral energy distribution in the near infrared. The emission of 12^{12}CO is much more extended, with a 68%\% enclosing flux radius of 75 \,AU. The large difference of the mm dust and gas extents (>5>5) strongly points to the occurrence of radial drift, and matches well the predictions of theoretical models
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