27 research outputs found

    Detection of TiO and VO in the atmosphere of WASP-121b and Evidence for its temporal variation

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    We report the transit observations of the ultra hot Jupiter WASP-121b using the Goodman High Throughput Spectrograph (GHTS) at the 4-meter ground-based telescope Southern Astrophysical Research Telescope (SOAR), covering the wavelength range 502900502-900 nm. By dividing the target and reference star into 19 spectroscopic passbands and applying differential spectrophotometry, we derive spectroscopic transit light curves and fit them using Gaussian process framework to determine transit depths for every passbands. The obtained optical transmission spectrum shows a steep increased slope toward the blue wavelength, which seems to be too steep to be accounted for by the Rayleigh scattering alone. We note that the transmission spectrum from this work and other works differ obviously from each other, which was pointed out previously by \citet{Wilson2021} as evidence for temporal atmospheric variation. We perform a free chemistry retrieval analysis on the optical transmission spectra from this work and the literature HST/WFC3 NIR spectrum. We determine TiO, VO and H2_{2}O with abundances of 5.950.42+0.47-5.95_{-0.42}^{+0.47} dex, 6.721.79+0.51-6.72_{-1.79}^{+0.51} dex, and 4.130.46+0.63-4.13_{-0.46}^{+0.63} dex, respectively. We compare the abundances of all these three molecules derived from this work and previous works, and find that they are not consistent with each other, indicating the chemical compositions of the terminator region may change over long timescales. Future multi-epoch and high-precision transit observations are required to further confirm this phenomena. We note that when combining the transmission spectra in the optical and in NIR in retrieval analysis, the abundances of V and VO, the NIR-to-optical offset and the cloud deck pressure may be coupled with each other.Comment: 23 pages, 13 figures, 6 tables. Accepted for publication in Research in Astronomy and Astrophysic

    Thermal Emission from the Hot Jupiter WASP-103b in JJ and KsK_{\rm s} Bands

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    Hot Jupiters, particularly those with temperature higher than 2000\,K are the best sample of planets that allow in-depth characterization of their atmospheres. We present here a thermal emission study of the ultra hot Jupiter WASP\mbox{-}103\,b observed in two secondary eclipses with CFHT/WIRCam in JJ and KsK_{\rm s} bands. By means of high precision differential photometry, we determine eclipse depths in JJ and KsK_{\rm s} to an accuracy of 220 and 270\,ppm, which are combined with the published HST/WFC3 and Spitzer data to retrieve a joint constraints on the properties of WASP-103\,b dayside atmosphere. We find that the atmosphere is best fit with a thermal inversion layer included. The equilibrium chemistry retrieval indicates an enhanced C/O (1.350.17+0.14^{+0.14}_{-0.17}) and a super metallicity with [Fe/H]=2.190.63+0.51=2.19^{+0.51}_{-0.63} composition. Given the near-solar metallicity of WASP-103 of [Fe/H]=0.06, this planet seems to be \sim100 more abundant than its host star. The free chemistry retrieval analysis yields a large abundance of FeH, H^{-}, CO2_2 and CH4_4. Additional data of better accuracy from future observations of JWST should provide better constraint of the atmospheric properties of WASP-103b

    B Cells Regulate Neutrophilia during Mycobacterium tuberculosis Infection and BCG Vaccination by Modulating the Interleukin-17 Response

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    We have previously demonstrated that B cells can shape the immune response to Mycobacterium tuberculosis, including the level of neutrophil infiltration and granulomatous inflammation at the site of infection. The present study examined the mechanisms by which B cells regulate the host neutrophilic response upon exposure to mycobacteria and how neutrophilia may influence vaccine efficacy. To address these questions, a murine aerosol infection tuberculosis (TB) model and an intradermal (ID) ear BCG immunization mouse model, involving both the μMT strain and B cell-depleted C57BL/6 mice, were used. IL (interleukin)-17 neutralization and neutrophil depletion experiments using these systems provide evidence that B cells can regulate neutrophilia by modulating the IL-17 response during M. tuberculosis infection and BCG immunization. Exuberant neutrophilia at the site of immunization in B cell-deficient mice adversely affects dendritic cell (DC) migration to the draining lymph nodes and attenuates the development of the vaccine-induced Th1 response. The results suggest that B cells are required for the development of optimal protective anti-TB immunity upon BCG vaccination by regulating the IL-17/neutrophilic response. Administration of sera derived from M. tuberculosis-infected C57BL/6 wild-type mice reverses the lung neutrophilia phenotype in tuberculous μMT mice. Together, these observations provide insight into the mechanisms by which B cells and humoral immunity modulate vaccine-induced Th1 response and regulate neutrophila during M. tuberculosis infection and BCG immunization. © 2013 Kozakiewicz et al

    Aerial Seeding: An Effective Forest Restoration Method in Highly Degraded Forest Landscapes of Sub-Tropic Regions

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    Carbon stock is an important indicator of cumulative ecosystem productivity. Using this indicator, and based on field sampling data, this paper compared the long-term difference in carbon stocks between aerial seeding (AS) and natural regeneration (NR) forests of Pinus massoniana in sub-tropic forests, China, in order to assess the effectiveness of AS in a highly degraded forest landscape. The results showed that the carbon stocks of stems, branches, roots, and trees (including stems, branches, leaves, and roots) were 140%, 85%, 110%, and 110%, significantly higher (p 21 years), those differences became statistically insignificant (p > 0.05). The total carbon stocks of the two forest types also showed a similar pattern. Those results clearly demonstrate that AS was an effective mean for restoring carbon stocks in highly degraded areas, even though their early growth was lower than the NR forests, and thus can be applied in the regions where the areas with limited seed sources and road accessibility.Arts and Sciences, Irving K. Barber School of (Okanagan)Non UBCEarth and Environmental Sciences, Department of (Okanagan)ReviewedFacult

    The association between alcohol drinking and glycemic management among people with type 2 diabetes in China

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    Abstract Introduction To investigate the association between alcohol drinking and glycemic management among adult patients with type 2 diabetes in regional China. Materials and Methods In this cross‐sectional survey conducted in Nanjing Municipality of China in 2018, adult type 2 diabetes patients were randomly selected from urban and rural communities. The outcome variable was the glycemic management status. The explanatory measure was alcohol drinking. Mixed‐effects regression models were employed to estimate odds ratios (ORs) and 95% confidence interval (95% CI) for examining the associations of alcohol drinking with glycemic management among type 2 diabetes patients. Results Among the overall 5,663 participants, the glycemic management rate was 39.8% (95% CI = 38.5, 41.1), with 41.2% (95% CI = 39.7, 42.7), 43.9% (95% CI = 38.9, 48.8), and 34.1% (95% CI = 31.5, 36.7) for non‐drinkers, mild/moderate drinkers, and heavy drinkers, respectively. After adjustment for potential confounders and community‐level clustering effect, heavy and mild/moderate alcohol drinkers were at 0.76 (95% CI = 0.66, 0.89) and 1.04 (95% CI = 0.87, 1.28) times odds to have glycemia under control than non‐drinkers among the overall participants. Furthermore, when stratified separately by gender and use of anti‐diabetes agents, the scenario within men, either regular or irregular users of anti‐diabetes agents was the same as that for overall participants, while the association between alcohol drinking and glycemic management became non‐significant among women. Conclusions Heavy alcohol drinking might have a negative effect on glycemic management among patients with type 2 diabetes irrespective of the use of anti‐diabetes agents in regional China. This study has important public health implications regarding precision intervention on patients' glycemia control for type 2 diabetes management

    Atmospheric composition of WASP-85Ab with ESPRESSO/VLT observations

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    Transit spectroscopy is the most frequently used technique to reveal the atmospheric properties of exoplanets. At high resolution, it has the added advantage of resolving the small Doppler shift of spectral lines and, thus, the trace signal of the exoplanet atmosphere can be extracted separately. We obtained the transmission spectra of the extrasolar planet WASP-85Ab, a hot Jupiter in a 2.655-day orbit around a G5, V = 11.2 mag host star, observed by the high-resolution spectrograph ESPRESSO at the Very Large Telescope array for three transits. We present an analysis of the Rossiter-McLaughlin (RM) effect on WASP-85A and determine a spin-orbit angle λ = −16.155°−2.879+2.916, suggesting that the planet is in a nearly aligned orbit. Combining the transmission spectra of three nights, we tentatively detected Hα and Call absorption with ⪆3σ via direct visual inspection of the transmission spectra with the center-to-limb variation and the Rossiter-McLaughlin effects removed; these absorptions still remain visible after excluding the cores of these strong lines with a 0.1Å mask. These spectral signals appear likely to have originated from the planetary atmosphere, but we cannot fully exclude a stellar origin. Via the cross-correlation analysis of a set of atoms and molecules, Li 

    Novel Hybrid Virtual Screening Protocol Based on Molecular Docking and Structure-Based Pharmacophore for Discovery of Methionyl-tRNA Synthetase Inhibitors as Antibacterial Agents

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    Methione tRNA synthetase (MetRS) is an essential enzyme involved in protein biosynthesis in all living organisms and is a potential antibacterial target. In the current study, the structure-based pharmacophore (SBP)-guided method has been suggested to generate a comprehensive pharmacophore of MetRS based on fourteen crystal structures of MetRS-inhibitor complexes. In this investigation, a hybrid protocol of a virtual screening method, comprised of pharmacophore model-based virtual screening (PBVS), rigid and flexible docking-based virtual screenings (DBVS), is used for retrieving new MetRS inhibitors from commercially available chemical databases. This hybrid virtual screening approach was then applied to screen the Specs (202,408 compounds) database, a structurally diverse chemical database. Fifteen hit compounds were selected from the final hits and shifted to experimental studies. These results may provide important information for further research of novel MetRS inhibitors as antibacterial agents
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