53 research outputs found

    Ghrelin Infusion in Humans Induces Acute Insulin Resistance and Lipolysis Independent of Growth Hormone Signaling

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    OBJECTIVE—Ghrelin is a gut-derived peptide and an endogenous ligand for the growth hormone (GH) secretagogue receptor. Exogenous ghrelin stimulates the release of GH (potently) and adrenocorticotropic hormone (ACTH) (moderately). Ghrelin is also orexigenic, but its impact on substrate metabolism is controversial. We aimed to study direct effects of ghrelin on substrate metabolism and insulin sensitivity in human subjects

    Investigating the causal effect of smoking on hay fever and asthma: a Mendelian randomization meta-analysis in the CARTA consortium

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    AbstractObservational studies on smoking and risk of hay fever and asthma have shown inconsistent results. However, observational studies may be biased by confounding and reverse causation. Mendelian randomization uses genetic variants as markers of exposures to examine causal effects. We examined the causal effect of smoking on hay fever and asthma by using the smoking-associated single nucleotide polymorphism (SNP) rs16969968/rs1051730. We included 231,020 participants from 22 population-based studies. Observational analyses showed that current vs never smokers had lower risk of hay fever (odds ratio (OR) = 0·68, 95% confidence interval (CI): 0·61, 0·76; P &lt; 0·001) and allergic sensitization (OR = 0·74, 95% CI: 0·64, 0·86; P &lt; 0·001), but similar asthma risk (OR = 1·00, 95% CI: 0·91, 1·09; P = 0·967). Mendelian randomization analyses in current smokers showed a slightly lower risk of hay fever (OR = 0·958, 95% CI: 0·920, 0·998; P = 0·041), a lower risk of allergic sensitization (OR = 0·92, 95% CI: 0·84, 1·02; P = 0·117), but higher risk of asthma (OR = 1·06, 95% CI: 1·01, 1·11; P = 0·020) per smoking-increasing allele. Our results suggest that smoking may be causally related to a higher risk of asthma and a slightly lower risk of hay fever. However, the adverse events associated with smoking limit its clinical significance.</jats:p

    Planck pre-launch status: The optical system

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    Planck is a scientific satellite that represents the next milestone in space-based research related to the cosmic microwave background, and in many other astrophysical fields. Planck was launched on 14 May of 2009 and is now operational. The uncertainty in the optical response of its detectors is a key factor allowing Planck to achieve its scientific objectives. More than a decade of analysis and measurements have gone into achieving the required performances. In this paper, we describe the main aspects of the Planck optics that are relevant to science, and the estimated in-flight performance, based on the knowledge available at the time of launch. We also briefly describe the impact of the major systematic effects of optical origin, and the concept of in-flight optical calibration. Detailed discussions of related areas are provided in accompanying papers

    The Ariel payload design post-PDR

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    The Ariel space mission will characterize spectroscopically the atmospheres of a large and diverse sample of hundreds of exoplanets. Through the study of targets with a wide range of planetary parameters (mass, density, equilibrium temperature) and host star types the origin for the diversity observed in known exoplanets will be better understood. Ariel is an ESA Medium class science mission (M4) with a spacecraft bus developed by industry under contract to ESA, and a Payload provided by a consortium of national funding agencies in ESA member states, plus contributions from NASA, the CSA and JAXA. The payload is based on a 1-meter class telescope operated at below 60K, built all in Aluminium, which feeds two science instruments. A multi-channel photometer and low-resolution spectrometer instrument (the FGS, Fine Guidance System instrument) operating from 0.5 – 1.95 microns in wavelength provides both guidance information for stabilizing the spacecraft pointing as well as vital scientific information from spectroscopy in the near-infrared and photometry in the visible channels. The Ariel InfraRed Spectrometer (AIRS) instrument provides medium resolution spectroscopy from 1.95 – 7.8 microns wavelength coverage over two instrument channels. Supporting subsystems provide the necessary mechanical, thermal and electronics support to the cryogenic payload. This paper presents the overall picture of the payload for the Ariel mission. The payload tightly integrates the design and analysis of the various payload elements (including for example the integrated STOP analysis of the Telescope and Common Optics) in order to allow the exacting photometric stability requirements for the mission to be met. The Ariel payload has passed through the Preliminary Design Review (completed in Q2 2023) and is now developing and building prototype models of the Telescope, Instruments and Subsystems (details of which will be provided in other contributions to this conference). This paper will present the current status of the development work and outline the future plans to complete the build and verification of the integrated payload

    Enabling planetary science across light-years. Ariel Definition Study Report

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    Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution
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