460 research outputs found

    Clouds in the atmospheres of extrasolar planets. II. Thermal emission spectra of Earth-like planets influenced by low and high-level clouds

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    We study the impact of multi-layered clouds (low-level water and high-level ice clouds) on the thermal emission spectra of Earth-like planets orbiting different types of stars. Clouds have an important influence on such planetary emission spectra due to their wavelength dependent absorption and scattering properties. We also investigate the influence of clouds on the ability to derive information about planetary surface temperatures from low-resolution spectra.Comment: accepted for publication in A&

    The extrasolar planet Gliese 581 d: a potentially habitable planet? (Corrigendum to arXiv:1009.5814)

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    We report here that the equation for H2O Rayleigh scattering was incorrectly stated in the original paper [arXiv:1009.5814]. Instead of a quadratic dependence on refractivity r, we accidentally quoted an r^4 dependence. Since the correct form of the equation was implemented into the model, scientific results are not affected.Comment: accepted to Astronomy&Astrophysic

    Hunt for Starspots in HARPS Spectra of G and K Stars

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    We present a method for detecting starspots on cool stars using the cross-correlation function (CCF) of high resolution molecular spectral templates applied to archival high-resolution spectra of G and K stars observed with HARPS/HARPS-N. We report non-detections of starspots on the Sun even when the Sun was spotted, the solar twin 18 Scorpii, and the very spotted Sun-like star HAT-P-11, suggesting that Sun-like starspot distributions will be invisible to the CCF technique, and should not produce molecular absorption signals which might be confused for signatures of exoplanet atmospheres. We detect strong TiO absorption in the T Tauri K-dwarfs LkCa 4 and AA Tau, consistent with significant coverage by cool regions. We show that despite the non-detections, the technique is sensitive to relatively small spot coverages on M dwarfs and large starspot areas on Sun-like stars.Comment: 12 pages, 8 figures, accepted to A

    Impact of risk factor control interventions for smoking cessation and promotion of healthy lifestyles in patients with periodontitis: a systematic review

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    Aim: The aim of this systematic review was to identify the most recent widely accepted guidelines for risk factor control interventions and to assess their impact in patients with periodontitis. Materials and methods: The electronic search strategy included a first systematic search to identify guidelines for interventions for smoking cessation, diabetes control, physical exercise (activity), change of diet, carbohydrate (dietary sugar) reduction and weight loss in the general population and a second systematic search to identify the studies evaluating these interventions in periodontitis patients. Results: A total of 13 guidelines and 25 studies were selected. Most guidelines included recommendations for all healthcare providers to provide interventions and follow-up counselling with the risk factors considered in the present review. In patients with periodontitis, interventions for smoking cessation and diabetes control were shown to improve periodontal health while the impact of dietary interventions and the promotion of other healthy lifestyles were moderate or limited. Conclusions: While aiming to improve treatment outcomes and the maintenance of periodontal health, current evidence suggests that interventions for smoking cessation and diabetes control are effective, thus emphasizing the need of behavioural support in periodontal care

    Promoting behavioural changes to improve oral hygiene in patients with periodontal diseases: a systematic review

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    Aim: This systematic review investigates the impact of specific interventions aiming at promoting behavioural changes to improve oral hygiene (OH) in patients with periodontal diseases. Methods: A literature search was performed on different databases up to March 2019. Randomized and non-randomized controlled trials evaluating the effects of behavioural interventions on plaque and bleeding scores in patients with gingivitis or periodontitis were considered. Pooled data analysis was conducted by estimating standardized mean difference between groups. Results: Of 288 articles screened, 14 were included as follows: 4 studies evaluated the effect of motivational interviewing (MI) associated with OH instructions, 7 the impact of oral health educational programmes based on cognitive behavioural therapies, and 3 the use of self-inspections/videotapes. Studies were heterogeneous and reported contrasting results. Meta-analyses for psychological interventions showed no significant group difference for both plaque and bleeding scores. No effect was observed in studies applying self-inspection/videotapes. Conclusions: Within the limitations of the current evidence, OH may be reinforced in patients with periodontal diseases by psychological interventions based on cognitive constructs and MI principles provided by oral health professionals. However, no conclusion can be drawn on their specific clinical efficacy as measured by reduction of plaque and bleeding scores over time

    Discrepancy between the CHEOPS and TESS eclipse depths

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    Recent studies based on photometry from the Transiting Exoplanet Survey Satellite (TESS) have suggested that the dayside of KELT-1b, a strongly irradiated brown dwarf, is significantly brighter in visible light than what would be expected based on Spitzer observations in the infrared. We observed eight eclipses of KELT-1b with CHaracterising ExOPlanet Satellite (CHEOPS) to measure its dayside brightness temperature in the bluest passband observed so far, and we jointly modelled the CHEOPS photometry with the existing optical and near-infrared photometry from TESS, LBT, CFHT, and Spitzer. Our modelling has led to a self-consistent dayside spectrum for KELT-1b covering the CHEOPS, TESS, H, Ks, and Spitzer IRAC 3.6 and 4.5 µm bands, where our TESS, H, Ks, and Spitzer band estimates largely agree with the previous studies. However, we discovered a strong discrepancy between the CHEOPS and TESS bands. The CHEOPS observations yield a higher photometric precision than the TESS observations, but they do not show a significant eclipse signal, while a deep eclipse is detected in the TESS band. The derived TESS geometric albedo of 0.36−0.13+0.12 is difficult to reconcile with a CHEOPS geometric albedo that is consistent with zero because the two passbands have considerable overlap. Variability in cloud cover caused by the transport of transient nightside clouds to the dayside could provide an explanation for reconciling the TESS and CHEOPS geometric albedos, but this hypothesis needs to be tested by future observations
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