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CALIPSO and the field campaigns: a convergence of interest for the study of clouds and aerosols
No full textInternational audienceThe study of the Earth's meteorological atmosphere by satellite took off in the 1970s. The firstradiometric observations, however, provided very little vertical information until the more recent useof active sounders. This coincided, in the 1980s, with the scientific community becoming aware thatbetter knowledge of cloud and aerosol properties and associated radiative forcing and interactionswas necessary for numerical weather prediction and the study of the climate. This search wasconcretized by several major field experiments and the development of new active remote sensingsystems implemented in stations, airborne, balloon-borne and space platforms (the Lidar In-spaceTechnology Experiment was flown by NASA onboard the Space Shuttle Discovery in 1994).CALIPSO and CloudSat platforms carrying active sounders were integrated into a constellation ofsatellites (A-Train) led by the AQUA satellite in 2006. These satellites were placed in very closeorbits allowing co-located and almost simultaneous observations. This technological breakthroughhas enabled an unprecedented synergy for Earth observation. It is now clear that understandingclimatic and meteorological processes on local to global scales requires instrumental synergyinvolving space-based resources, and more specifically lidar and radar observations. It has beenshown that a combination of observations made by well-dimensioned ground-based networks andairborne measurements was essential to address process studies at various scales in field experiments.Such synergies have been developed in major international programs supported by France and theEuropean community, often in collaboration with NASA. CALIPSO in the A-Train constellation wasa key element of these observations not just for a validation need, but also to learn from each otherand provide a scale extension.French expertise in the field of active remote sensing for atmospheric measurement was crucial inthis approach, thanks to the development of new lidar and radar facilities and related synergeticexploitation algorithms, as supported by CNRS and CNES. We will present examples of thescientific results that have been made available to the international scientific community. The role ofCALIPSO observations will be highlighted in different parts of the globe, namely in the Tropics withthe African Monsoon Multidisciplinary Analysis (AMMA), the Aerosol, Radiation and Clouds insouthern Africa (AEROCLO-sA) or the Elucidating the Role of Clouds-Circulation Coupling inClimate (EUREC4A) programs, in the Mediterranean and in the Arctic, as well as at the global scale(via the exploitation of the synergetic products derived from the Lidar-Radar algorithms to constrainradiation budget). The observations notably made it possible to evolve the physics of the modelsleading to a reduction in radiative biases.The climatological database obtained between 2006 and 2023 on clouds and aerosols from CALIPSOand CloudSat now constitutes a reference for the long-term monitoring of clouds and aerosols and thestudy of remarkable or extreme phenomena involving aerosol-cloud-dynamics interaction process(cyclones, massive volcanic, dust or biomass burning aerosols transport across continents and oceans,megafires, etc...). These missions will serve as a reference for the next EarthCare mission(collaboration between the European Space Agency and the Japanese agency JAXA) and future one
Magnetospheric Venus Space Explorers (MVSE) mission: A proposal for understanding the dynamics of induced magnetospheres
No full textInternational audienceInduced magnetospheres form around planetary bodies with atmospheres through the interactionof the solar wind with their ionosphere. Induced magnetospheres are highly dependent on the so-lar wind conditions and have only been studied with single spacecraft missions in the past. Thisgap in knowledge could be addressed by a multi-spacecraft plasma mission, optimized for study-ing global spatial and temporal variations in the magnetospheric system around Venus, whichhosts the most prominent example of an induced magnetosphere in our solar system. The MVSEmission comprises four satellites, of which three are identical scientific spacecraft, carrying thesame suite of instruments probing different regions of the induced magnetosphere and the solarwind simultaneously. The fourth spacecraft is the transfer vehicle which acts as a relay satellitefor communications at Venus. In this way, changes in the solar wind conditions and extremesolar events can be observed, and their effects can be quantified as they propagate through theVenusian induced magnetosphere. Additionally, energy transfer in the Venusian induced mag-netosphere can be investigated. The scientific payload includes instrumentation to measure themagnetic field, electric field, and ion-electron velocity distributions. This study presents thescientific motivation for the mission as well as requirements and the resulting mission design.Concretely, a mission timeline along with a complete spacecraft design, including mass, power,communication, propulsion and thermal budgets are given. This mission was initially conceivedat the Alpbach Summer School 2022 and refined during a week-long study at ESA’s ConcurrentDesign Facility in Redu, Belgiu
G-quadruplex ligands as potent lysosome regulators
No full textInternational audienceGuanine-quadruplex structures (G4) are unusual nucleic acid conformations formed by guanine-rich DNA and RNA sequences and known to control gene expression mechanisms, from transcription to protein synthesis. So far, a number of molecules that recognize G4 have been developed for potential therapeutic applications in human pathologies, including cancer and infectious diseases. These molecules are called G4 ligands. When the biological effects of G4 ligands are studied, the analysis is often limited to nucleic acid targets. However, recent evidence indicates that G4 ligands may target other cellular components and compartments such as lysosomes and mitochondria. Here, we summarize our current knowledge of the regulation of lysosome by G4 ligands, underlying their potential functional impact on lysosome biology and autophagic flux, as well as on the transcriptional regulation of lysosomal genes. We outline the consequences of these effects on cell fate decisions and we systematically analyzed G4-prone sequences within the promoter of 435 lysosome-related genes. Finally, we propose some hypotheses about the mechanisms involved in the regulation of lysosomes by G4 ligands
Search for violation in D KK decays in proton-proton collisions at = 13 TeV
No full textInternational audienceA search is reported for charge-parity D KK violation in D KK decays, using data collected in proton-proton collisions at = 13 TeV recorded by the CMS experiment in 2018. The analysis uses a dedicated data set that corresponds to an integrated luminosity of 41.6 fb, which consists of about 10 billion events containing a pair of ẖadrons, nearly all of which decay to charm hadrons. The flavor of the neutral D meson is determined by the pion charge in the reconstructed decays D D and D D. The D KK asymmetry in D KK is measured to be ( KK) = (6.2 3.0 0.2 0.8)%, where the three uncertainties represent the statistical uncertainty, the systematic uncertainty, and the uncertainty in the measurement of the D KK asymmetry in the D K decay. This is the first D KK asymmetry measurement by CMS in the charm sector as well as the first to utilize a fully hadronic final state
Combination of measurements of the top quark mass from data collected by the ATLAS and CMS experiments at and 8 TeV
No full textInternational audienceA combination of fifteen top quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The data sets used correspond to an integrated luminosity of up to 5 and 20 of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, respectively. The combination includes measurements in top quark pair events that exploit both the semileptonic and hadronic decays of the top quark, and a measurement using events enriched in single top quark production via the electroweak -channel. The combination accounts for the correlations between measurements and achieves an improvement in the total uncertainty of 31% relative to the most precise input measurement. The result is = 172.52 0.14 (stat) 0.30 (syst) GeV, with a total uncertainty of 0.33 GeV
The circularly permuted globin domain of Androglobin exhibits atypical heme stabilization and nitric oxide interaction
No full textInternational audienceIn the decade since the discovery of androglobin, a multi-domain hemoglobin of metazoans associated with ciliogenesis and spermatogenesis, there has been little advance in the knowledge of the biochemical and structural properties of this unusual member of the hemoglobin superfamily. Using a method for aligning remote homologues, coupled with molecular modelling and molecular dynamics, we have identified a novel structural alignment to other hemoglobins. This has led to the first stable recombinant expression and characterization of the circularly permuted globin domain. Exceptional for eukaryotic globins is that a tyrosine takes the place of the highly conserved phenylalanine in the CD1 position, a critical point in stabilizing the heme. A disulfide bond, similar to that found in neuroglobin, forms a closed loop around the heme pocket, taking the place of androglobin’s missing CD loop and further supporting the heme pocket structure. Highly unusual in the globin superfamily is that the heme iron binds nitric oxide as a five-coordinate complex similar to other heme proteins that have nitric oxide storage functions. With rapid autoxidation and high nitrite reductase activity, the globin appears to be more tailored toward nitric oxide homeostasis or buffering. The use of our multi-template profile alignment method to yield the first biochemical characterisation of the circularly permuted globin domain of androglobin expands our knowledge of the fundamental functioning of this elusive protein and provides a pathway to better define the link between the biochemical traits of androglobin with proposed physiological functions
Learning from the construction of Environmental Performance Indicators in new project development: a case study
No full textInternational audienceThis study examines the construction, dynamics and appropriation of Environmental Performance Indicators (EPIs) within an organization, specifically focusing on their development process. Over the course of a year, the author conducted more than 50 interviews and 30 meetings with stakeholders to analyze the development of EPIs in new product development. The research highlights the roles of experts, project teams, and executive management in EPI construction, emphasizing stakeholder learning and compromises. The findings enrich the discussion on stakeholder integration in EPI processes and the roles of eco-design tools, particularly during preliminary development stages, addressing the gap between academic research and practical application
Antoine & les molécules photo-activables contre le cancer (Podcast), Episode 9 de Voyage au centre de la thèse (Institut Polytechnique de Paris)
No full texthttps://octopus.saooti.com/main/pub/podcast/55951
Hydratation en solutions diluées de brownmillerite extraite de ciments SR et de brownmillerite synthétique
No full textInternational audienceThe aim of this study is to investigate the reactivity of ferrites extracted from Sulfate Resisting (SR) Portland cement clinkers, until now often neglected. Industrial materials and synthetic materials have been studied and compared in the whole range of the Al/Fe ratio. Highly diluted aqueous suspensions were used, ranging betweenpure water and more complex solutions simulating the pore solution in cement. Conductimetry was combined with ICP.The reactivity of ferrite depends on the environment and the aluminum content of ferrite. The reactivity of ferrites extracted from industrial SR0 and SR3 clinkers (C3A = 0 wt% and C3A ≤ 3 wt% respectively) can be distinguished from one another. Additionally, industrial ferrite was found to be more reactive than synthetic ferrite. The iron content of katoite and ettringite was investigated using XRD. It depends on the Al/Fe ratio offerrite and the presence of calcium hydroxide in the solution