184 research outputs found

    The atmospheres of rocky exoplanets : II. Influence of surface composition on the diversity of cloud condensates

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    O.H. acknowledges the PhD stipend form the University of St Andrews’ Centre for Exoplanet Science. P.W. and Ch.H. acknowledge funding from the European Union H2020-MSCA-ITN-2019 under Grant Agreement no. 860470 (CHAMELEON).Clouds are an integral part of planetary atmospheres, with most planets hosting clouds. Understanding not only the formation, but also the composition of clouds, is crucial to understand future observations. As observations of the planet's surface will remain very difficult, it is essential to link the observable high atmosphere gas and cloud composition to the surface conditions. We present a fast and simple chemical equilibrium model for the troposphere of rocky exoplanets, which is in chemical and phase equilibrium with the crust. The hydrostatic equilibrium atmosphere is built from bottom to top. In each atmospheric layer, chemical equilibrium is solved and all thermally stable condensates are removed, depleting the atmosphere above in the effected elements. These removed condensates build an upper limit for cloud formation and can be separated into high and low temperature condensates. The most important cloud condensates for 1000K >∼ Tgas >∼ 400K are KCl[s], NaCl[s], FeS[s], FeS2[s], FeO[s], Fe2O3[s], and Fe3O4[s]. For Tgas ∼< 400K H2O[l,s], C[s], NH3[s], NH4Cl[s], and NH4SH[s] are thermally stable, while for even lower temperatures of Tgas ≤ 150K CO2[s], CH4[s], NH3[s], and H2S[s] become stable. The inclusion of clouds with trace abundances results in the thermal stability of a total of 72 condensates for atmospheres with different surface conditions (300K ≤ Tsurf ≤ 1000K and psurf = 1 bar; 100 bar). The different cloud condensates are not independent of each other, but follow sequences of condensation, which are robust against changes in crust composition, surface pressure, and surface temperature. Independent of the existence of water as a crust condensate, H2O[l,s] is a thermally stable cloud condensate for all investigated elemental abundances. However, the water cloud base depends on the hydration level of the crust. Therefore, the detection of water condensates alone does not necessarily imply stable water on the surface, even if the temperature could allow for water condensation.Publisher PDFPeer reviewe

    Bergman kernel and complex singularity exponent

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    We give a precise estimate of the Bergman kernel for the model domain defined by ΩF={(z,w)Cn+1:ImwF(z)2>0},\Omega_F=\{(z,w)\in \mathbb{C}^{n+1}:{\rm Im}w-|F(z)|^2>0\}, where F=(f1,...,fm)F=(f_1,...,f_m) is a holomorphic map from Cn\mathbb{C}^n to Cm\mathbb{C}^m, in terms of the complex singularity exponent of FF.Comment: to appear in Science in China, a special issue dedicated to Professor Zhong Tongde's 80th birthda

    Ocular inflammatory events following COVID-19 vaccination: a multinational case series

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    Background: Inflammatory adverse events following COVID-19 vaccination are being reported amidst the growing concerns regarding vaccine’s immunogenicity and safety, especially in patients with pre-existing inflammatory conditions. Methods: Multinational case series of patients diagnosed with an ocular inflammatory event within 14 days following COVID-19 vaccination collected from 40 centres over a 3 month period in 2021. Results: Seventy patients presented with ocular inflammatory events within 14 days following COVID-19 vaccination. The mean age was 51 years (range, 19–84 years). The most common events were anterior uveitis (n = 41, 58.6%), followed by posterior uveitis (n = 9, 12.9%) and scleritis (n = 7, 10.0%). The mean time to event was 5 days and 6 days (range, 1–14 days) after the first and second dose of vaccine, respectively. Among all patients, 36 (54.1%) had a previous history of ocular inflammatory event. Most patients (n = 48, 68.6%) were managed with topical corticosteroids. Final vision was not affected in 65 (92.9%), whereas 2 (2.9%) and 3 (4.3%) had reduction in visual acuity reduced by ≤3 lines and &gt; 3 lines, respectively. Reported complications included nummular corneal lesions (n = 1, 1.4%), cystoid macular oedema (n = 2, 2.9%) and macular scarring (n = 2, 2.9%). Conclusion: Ocular inflammatory events may occur after COVID-19 vaccination. The findings are based on a temporal association that does not prove causality. Even in the possibility of a causal association, most of the events were mild and had a good visual outcome

    Clinical features and outcomes of patients with tubercular uveitis treated with antitubercular therapy in the collaborative ocular tuberculosis study (COTS)-1

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    IMPORTANCE Eradication of systemic tuberculosis (TB) has been limited by neglected populations and the HIV pandemic. Whereas ocular TB often presents as uveitis without any prior evidence of systemic TB, the existing uncertainty in the diagnosis of TB uveitis may perpetuate missed opportunities to address systemic TB. OBJECTIVE To examine the clinical features of TB uveitis and the associations with response to antitubercular therapy (ATT). DESIGN, SETTING, AND PARTICIPANTS This retrospective multinational cohort study included patients from 25 ophthalmology referral centers diagnosed with TB uveitis and treated with ATT from January 1, 2004, through December 31, 2014, with a minimum follow-up of 1 year. MAIN OUTCOMES AND MEASURES Treatment failure, defined as a persistence or recurrence of inflammation within 6 months of completing ATT, inability to taper oral corticosteroids to less than 10mg/d or topical corticosteroid drops to less than 2 drops daily, and/or recalcitrant inflammation necessitating corticosteroid-sparing immunosuppressive therapy. RESULTS A total of 801 patients (1272 eyes) were studied (mean [SD] age, 40.5 [14.8] years; 413 [51.6%] male and 388 [48.4%] female; 577 [73.6%] Asian). Most patients had no known history (498 of 661 [75.3%]) of systemic TB. Most patients had bilateral involvement (471 of 801 [58.8%]). Common clinical signs reported include vitreous haze (523 of 1153 [45.4%]), retinal vasculitis (374 of 874 [42.8%]), and choroidal involvement (419 of 651 [64.4%]). Treatment failure developed in 102 of the 801 patients (12.7%). On univariate regression analysis, the hazard ratios (HRs) associated with intermediate uveitis (HR, 2.21; 95%CI, 1.07-4.55; P = .03), anterior uveitis (HR, 2.68; 95%CI, 1.32-2.35; P = .006), and panuveitis (HR, 3.28; 95%CI, 1.89-5.67; P &lt; .001) were significantly higher compared with posterior distribution. The presence of vitreous haze had a statistically significant association (HR, 1.95; 95%CI, 1.26-3.02; P = .003) compared with absence of vitreous haze. Bilaterality had an associated HR of 1.50 (95%CI, 0.96-2.35) compared with unilaterality (HR, 1 [reference]), although this finding was not statistically significant (P = .07). On multivariate Cox proportional hazards regression analysis, the presence of vitreous haze had an adjusted HR of 2.98 (95%CI, 1.50-5.94; P = .002), presence of snow banking had an adjusted HR of 3.71 (95%CI, 1.18-11.62; P = .02), and presence of choroidal involvement had an adjusted HR of 2.88 (95%CI, 1.22-6.78; P = .02). CONCLUSIONS AND RELEVANCE A low treatment failure rate occurred in patients with TB uveitis treated with ATT. Phenotypes and test results are studied whereby patients with panuveitis having vitreous and choroidal involvement had a higher risk of treatment failure. These findings are limited by retrospectivemethods. A prospectively derived composite clinical risk score might address this diagnostic uncertainty through holistic and standardized assessment of the combinations of clinical features and investigation results that may warrant diagnosis of TB uveitis and treatment with ATT

    The effect of a preoperative subconjuntival injection of dexamethasone on blood–retinal barrier breakdown following scleral buckling retinal detachment surgery: a prospective randomized placebo-controlled double blind clinical trial

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    textabstractBackground: Blood-retinal barrier breakdown secondary to retinal detachment and retinal detachment repair is a factor in the pathogenesis of proliferative vitreoretinopathy (PVR). We wished to investigate whether an estimated 700 to 1000 ng/ml subretinal dexamethasone concentration at the time of surgery would decrease the blood-retinal barrier breakdown postoperatively. Methods: Prospective, placebo-controlled, double blind clinical trial. In 34 patients with rhegmatogenous retinal detachment scheduled for conventional scleral buckling retinal detachment surgery, a subconjunctival injection of 0.5 ml dexamethasone diphosphate (10 mg) or 0.5 ml placebo was given 5-6 hours before surgery. Differences in laser flare photometry (KOWA) measurements taken 1, 3 and 6 weeks after randomisation between dexamethasone and placebo were analysed using mixed model ANOVA, while correcting for the preoperative flare measurement. Results: Six patients did not complete the study, one because of recurrent detachment within 1 week, and five because they missed their postoperative laser flare visits. The use of dexamethasone resulted in a statistically significant decrease in laser flare measurements at the 1-week postoperative visit. Conclusion: The use of a preoperative subconjunctival injection of dexamethasone decreased 1-week postoperative blood-retina barrier breakdown in patients undergoing conventional scleral buckling retinal detachment surgery. This steroid priming could be useful as a part of a peri-operative regime that would aim at decreasing the incidence of PVR

    Optical imaging in vivo with a focus on paediatric disease: technical progress, current preclinical and clinical applications and future perspectives

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    To obtain information on the occurrence and location of molecular events as well as to track target-specific probes such as antibodies or peptides, drugs or even cells non-invasively over time, optical imaging (OI) technologies are increasingly applied. Although OI strongly contributes to the advances made in preclinical research, it is so far, with the exception of optical coherence tomography (OCT), only very sparingly applied in clinical settings. Nevertheless, as OI technologies evolve and improve continuously and represent relatively inexpensive and harmful methods, their implementation as clinical tools for the assessment of children disease is increasing. This review focuses on the current preclinical and clinical applications as well as on the future potential of OI in the clinical routine. Herein, we summarize the development of different fluorescence and bioluminescence imaging techniques for microscopic and macroscopic visualization of microstructures and biological processes. In addition, we discuss advantages and limitations of optical probes with distinct mechanisms of target-detection as well as of different bioluminescent reporter systems. Particular attention has been given to the use of near-infrared (NIR) fluorescent probes enabling observation of molecular events in deeper tissue

    Diagnostic tools in Rhinology EAACI position paper

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    This EAACI Task Force document aims at providing the readers with a comprehensive and complete overview of the currently available tools for diagnosis of nasal and sino-nasal disease. We have tried to logically order the different important issues related to history taking, clinical examination and additional investigative tools for evaluation of the severity of sinonasal disease into a consensus document. A panel of European experts in the field of Rhinology has contributed to this consensus document on Diagnostic Tools in Rhinology

    A definition of habit for socio-economics

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    The paper argues that it is a mistake to define habit as behaviour or action; as a regular conjunction of actions; as a stock; as a form of automaticity (although habit is acquired and activated automatically); as a tendency, propensity or disposition (even though habit acts tendentially); as a mechanism; and as a process (even though habit is acquired and activated via several processes). A taxonomic definition is provided wherein habit is a cognitive representation of a cue-action response
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