Search

Laser guide star Shack–Hartmann wavefront sensor images on extremely large telescopes (ELT) will be significantly elongated due to the off-axis projection of the laser relative to the subapertures. The finite number of pixels of the wavefront sensor detector means the most elongated images will be truncated, introducing errors in the centroid measurements. In this paper, we propose appending to the truncated wavefront sensor image the most likely missing tails from a high-resolution nontruncated reference image, which can be calculated from all of the low-resolution images. We show, via numerical simulation, that we can improve the centroid estimate for the most elongated subapertures on an ELT in the presence of read and photon noise.

This paper explores the possibilities offered by coupling C nanomanipulation with resonance Raman excitation profile approaches. We apply this method to nanostructures produced by AFM nanomanipulation. The experimental demonstration is made on the interaction between two single-wall carbon nanotubes, one semiconducting and the other metallic. The measurement is analyzed and discussed in terms of resonance shifts and broadening of the electronic transition. This paper focuses on the example of the interaction between one (18,0) metallic SWCNT with one (11,9) semiconductor SWCNT. Our experimental setup allows to measure the evolution of resonance width from 75 cm–1to 100 cm–1for an isolated carbon nanotube (CNT), to more than 200 cm–1for interacting CNTs.

Conformément à l’esprit des Ateliers de Giens, cet article rapporte les évolutions souhaitables du fonctionnement des Comités de protection des personnes (CPP) et des Comités d’éthique de la recherche (CER) en France. Ces comités jouent un rôle crucial dans l’évaluation éthique des projets de recherche clinique, un processus devenu plus complexe compte-tenu en particulier des évolutions récentes législatives, réglementaires et méthodologiques. Le résultat de cette réflexion met en lumière les défis actuels auxquels les CPP font face, notamment la charge croissante de travail, la complexité des dossiers à traiter et le besoin d’un meilleur usage de leurs ressources. Pour y répondre, plusieurs recommandations sont proposées. Parmi celles-ci figurent l’amélioration de l’accompagnement des promoteurs avant la soumission des dossiers, la simplification des tâches administratives pour les membres des CPP et l’amélioration des outils informatiques. L’article souligne également le besoin d’évaluation continue des activités des CPP pour contribuer à la qualité et la cohérence de leurs avis, ainsi que l’importance de rendre cette activité plus attractive pour les professionnels qualifiés, en leur proposant des indemnisations et une reconnaissance professionnelle adéquates. Pour le bénéfice de l’ensemble des acteurs de la recherche en santé, il est fortement souhaité le développement d’une base documentaire unique accessible à tous et regroupant toutes les informations et modèles de documents utiles. Concernant les CER, qui agissent actuellement sans cadre juridique, il est en particulier proposé que leur développement se fasse dans des conditions de conformité à des principes essentiels de collégialité, de transparence et de gestion appropriée des liens d’intérêts. Enfin, il est apparu nécessaire que la Commission nationale des recherches impliquant la personne humaine (CNRIPH) bénéficie de ressources appropriées pour remplir efficacement ses missions incluant la coordination des CPP et l’élaboration de programmes de formation adaptés pour leurs membres. Ces recommandations visent à améliorer les conditions de fonctionnement des CPP et CER, assurant l’éthique des recherches engagées, ainsi que la qualité des résultats de ces dernières.

The low‐altitude, high‐velocity trajectory of the Juno spacecraft enables the Jovian Auroral Distributions Experiment to make the first in situ observations of the high‐latitude ionospheric plasma. Ions are observed to energies below 1 eV. The high‐latitude ionospheric ions are observed simultaneously with a loss cone in the magnetospheric ions, suggesting precipitating magnetospheric ions contribute to the heating of the upper ionosphere, raising the scale height, and pushing ionospheric ions to altitudes of 0.5 RJabove the planet where they are observed by Jovian Auroral Distributions Experiment. The source of the magnetospheric ions is tied to the Io torus and plasma sheet, indicated by the cutoff seen in both the magnetospheric and ionospheric plasma at the Io M‐shells. Equatorward of the Io M‐shell boundary, the ionospheric ions are not observed, indicating a drop in the scale height of the ionospheric ions at those latitudes. The Jovian Auroral Distributions Experiment (JADE) ion sensor has made the first in situ observations of the upper, high‐latitude ionosphere of Jupiter. Flown on the Juno spacecraft, JADE observes the ionosphere at altitudes of approximately half a Jovian radii, with the spacecraft traveling at the high speed of ~50 km/s. For comparison, a proton traveling at 50 km/s has an energy of approximately 10 eV. The combination of the low‐altitude and high ram velocity enables JADE to measure ionospheric ions to energies below 1 eV. These observations reveal a cold ionospheric population of protons at high latitudes, seen coincident with precipitating magnetospheric ions. This indicates that the precipitating magnetospheric ions heat the upper ionosphere, raising the height where these protons can be observed. The ionospheric protons are seen in bands in the northern and southern latitudes, bounded on the equator edge by the field lines that connect to Io, and inside the auroral oval to the poleward side. The high‐latitude ionosphere is observed between the magnetic latitudes bounded by the auroral oval and Io's magnetic flux shellTwo populations are observed at high latitudes: (1) magnetospheric ions consisting of H, S, and O ions and (2) cold ionospheric H+ionsObservation of a loss cone suggests precipitating magnetospheric ions heat the upper ionosphere to heights ~0.5 RJabove the clouds

Étudier les résultats de l’ossiculoplastie dans une série pédiatrique et rechercher les facteurs prédictifs d’efficacité.

We compare electron and UV observations mapping to the same location in Jupiter's northern polar region, poleward of the main aurora, during Juno perijove 5. Simultaneous peaks in UV brightness and electron energy flux are identified when observations map to the same location at the same time. The downward energy flux during these simultaneous observations was not sufficient to generate the observed UV brightness; the upward energy flux was. We propose that the primary acceleration region is below Juno's altitude, from which the more intense upward electrons originate. For the complete interval, the UV brightness peaked at ~240 kilorayleigh (kR); the downward and upward energy fluxes peaked at 60 and 700 mW/m2, respectively. Increased downward energy fluxes are associated with increased contributions from tens of keV electrons. These observations provide evidence that bidirectional electron beams with broad energy distributions can produce tens to hundreds of kilorayleigh polar UV emissions. Jupiter's ultraviolet (UV) aurora is produced by electrons that precipitate into the planet's atmosphere and interact with hydrogen molecules. A number of different UV auroral emission regions have been identified such as the main aurora, the aurora associated with Jupiter's satellites, and the polar aurora located poleward of the main aurora. We examine electron and UV observations from Juno in Jupiter's northern polar region to investigate the processes responsible for producing Jupiter's polar aurora. We show electrons and UV emissions having simultaneous enhancements during a time when they map to the same location of Jupiter's upper atmosphere at the same time. We present evidence that electrons with energies between 0.1 and 100 kilo electron volts (keV) are capable of producing the polar UV emissions studied here and that further acceleration of these electrons may be occurring at altitudes below the spacecraft. Simultaneous peaks are observed in electron energy flux and UV brightness when they map to same location in Jupiter's polar region at the same timeUpward greater than downward electron energy fluxes are observed, suggesting that primary acceleration region may be below ~1.5 jovian radiiDownward energy fluxes able to produce tens to hundreds of kilorayleigh polar UV emissions are identified; increases in energy flux due to tens of keV electrons

During its polar orbits around Jupiter, Juno often crosses the boundaries of the Jovian magnetosphere (namely the magnetopause and bow shock). From the boundary locations, the upstream solar wind dynamic pressure can be inferred, which in turn illustrates the state of compression or relaxation of the system. The aim of this study is to examine Jovian radio emissions during magnetospheric compressions, in order to determine the relationship between the solar wind and Jovian radio emissions. In this paper, we give a complete list of bow shock and magnetopause crossings (from June 2016 to August 2022), and the associated solar wind dynamic pressure and standoff distances inferred from Joy et al. (2002, https://doi.org/10.1029/2001JA009146). We then select two sets of magnetopause crossings with moderate to strong compression of the magnetosphere for two case studies of the response of the Jovian radio emissions. We confirm that magnetospheric compressions lead to the activation of new radio sources. Newly activated broadband kilometric emissions are observed almost simultaneously with compression of the magnetosphere, with sources covering a large range of longitudes. Decametric emission sources are seen to be activated more than one rotation later only at specific longitudes and dusk local times. Finally, the activation of narrowband kilometric radiation is not observed until the magnetosphere is in its expansion phase. This paper provides a list of the Jovian magnetosphere boundary crossings by the Juno spacecraft from June 2016 to August 2022Jovian magnetospheric compressions lead to increased bKOM radio emissions (immediately) and DAM on the dusk sector (more than one rotation later)nKOM radio emission appears later during relaxation phase of the compression This paper provides a list of the Jovian magnetosphere boundary crossings by the Juno spacecraft from June 2016 to August 2022 Jovian magnetospheric compressions lead to increased bKOM radio emissions (immediately) and DAM on the dusk sector (more than one rotation later) nKOM radio emission appears later during relaxation phase of the compression

The Juno spacecraft crossed flux tubes connected to the Io footprint tail at low Jovian altitudes on multiple occasions. The transits covered longitudinal separations of approximately 10° to 120° along the footprint tail. Juno's suite of magnetospheric instruments acquired detailed measurements of the Io footprint tail. Juno observed planetward electron energy fluxes of ~70 mW/m2near the Io footprint and ~10 mW/m2farther down the tail, along with correlated, intense electric and magnetic wave signatures, which also decreased down the tail. All observed electron distributions were broad in energy, suggesting a dominantly broadband acceleration process, and did not show any broad inverted‐Vstructure that would be indicative of acceleration by a quasi‐static, discrete, parallel potential. Observed waves were primarily below the proton cyclotron frequency, yet identification of a definitive wave mode is elusive. Beyond 40° down the footprint tail, Juno observed depleted upward loss cones, suggesting that the broadband acceleration occurred at distances beyond Juno's transit distance of 1.3 to 1.7 RJ. For all transits, Juno observed fine structure on scales of approximately tens of kilometers and confirmed independently with electron and wave measurements that a bifurcated tail can intermittently exist. The Juno spacecraft crossed regions magnetically connected to auroral structures associated with Jupiter's moon Io on multiple occasions. The transits covered longitudinal separations of approximately 10° to 120° along Io's auroral tail. Juno's suite of instruments acquired detailed measurements of these auroral structures. Juno directly observed the electrons that sustain these auroral features before they crash into the atmosphere and generate the brilliant aurora. The flux of these electrons decreased as Juno transited the tail farther from Io's longitude. While there are two main explanations for Io's auroral signatures, the nature of the observed electrons in this work favors one mechanism over the other. When Juno was far from Io's longitude, the observations suggest that the spacecraft was below the point at which the electrons are accelerated into the atmosphere. For all transits, Juno observed fine structure on scales of approximately tens of kilometers and confirmed that a bifurcated tail can intermittently exist. Juno crossed flux tubes connected to Io's footprint tail aurora 10° to 120° downstream of the main Alfven wing (MAW) spotBroad power law‐like electron energy distributions suggest a primarily broadband acceleration mechanismJuno observed structure with ~20‐km resolution, bifurcated tails, and broadening with longitudinal separation from the MAW spot

Using Juno plasma, electric and magnetic field observations (from JADE, Waves, and MAG instruments), we show that electron conic distributions are commonly observed in Jovian radio sources. The conics are characterized by maximum fluxes at oblique pitch angles, ~20°–30° from the B field, both in the upward and downward directions. They constitute an efficient source of free energy for the cyclotron maser instability. Growth rates of ~3 to 7 × 104s−1are obtained for hectometric waves, leading to amplification by e10with propagation paths of 50–100 km. We show that stochastic acceleration due to interactions with a low‐frequency electric field turbulence located a few 104km above the ionosphere may form the observed conics. A possible source of turbulence could be inertial Alfvén waves, suggesting a connection between the auroral acceleration and generation of coherent radio emissions. Jupiter, as many astrophysical magnetized objects, is a powerful emitter of nonthermal radio emissions. The coherent process required for their generation is likely the cyclotron maser instability (CMI). However, the exact conditions of wave amplification are not known precisely at Jupiter. With Juno mission, for the first time, it is possible to explore the auroral regions of Jupiter, where the particles are accelerated and the nonthermal emissions produced. With several crossing of the radio sources, the free energy used by the CMI can now be identified. It corresponds to conic‐likedistributions, characterized by an accumulation of particles just outside the loss cones. Applying the CMI theory, large growth rates are obtained, showing that the conics probably play a central role in the wave generation source. The formation of the conics could be due to an interaction with a low‐frequency Alfvénic turbulence. This suggests a close relationship between the radio wave generation and the particle acceleration, as at Earth, the details of the scenario being, nevertheless, slightly different. Electron conics are observed by Juno in Jovian radio sources, and their role in the wave amplification is analyzedThe observed conics may very efficiently drive the cyclotron maser, from decametric to kilometric wavelength rangesThe formation of conics is modeled by a stochastic acceleration due to a low‐frequency parallel electric field turbulence

La loi dite « Clayes-Leonetti » modifie les pratiques de soins et les réflexions des équipes. Elle impose notamment la présence d’un médecin consultant lors des échanges relatifs à la mise en place de la sédation profonde et continue maintenue jusqu’au décès, positionnant les équipes de soins palliatifs en première ligne, de par la nouveauté et la complexité de ces situations. Notre équipe mobile de soins palliatifs est régulièrement sollicitée et c’est à travers la lecture de plusieurs situations cliniques que nous avons souhaité explorer ce que la loi a pu modifier dans nos pratiques. Il faut en effet noter que les modifications législatives peuvent générer des situations nouvelles, pourvoyeuses de dilemmes éthiques et cliniques ou de difficultés morales pour chacun, qu’il s’agit quotidiennement de mettre en mouvement au sein des équipes de soins, de façon à parvenir à asseoir une pratique clinique sécurisante pour les patients et les soignants.

We characterize the precipitating electrons accelerated in the Europa‐magnetosphere interaction by analyzing in situ measurements and remote sensing observations recorded during 10 crossings of the flux tubes connected to Europa's auroral footprint tail by Juno. The electron downward energy flux, ranging from 34 to 0.8 mW/m2, exhibits an exponential decay as a function of downtail distance, with an e‐folding factor of 7.4°. Electrons are accelerated at energies between 0.3 and 25 keV, with a characteristic energy that decreases downtail. The electron distributions form non‐monotonic spectra in the near tail (i.e., within an angular separation of less than 4°) that become broadband in the far tail. The size of the interaction region at the equator is estimated to be 4.2 ± 0.9 Europa radii, consistent with previous estimates based on theory and UV observations. The space environment close to Jupiter is dominated by the magnetic field of the giant planet in a so‐called magnetosphere. The four Galilean moons, including Europa, orbit deep inside the Jovian magnetosphere and therefore constantly interact with the rapidly rotating plasma flow made of charged particles trapped by the magnetic field of the giant planet. The interaction between moons and plasma generates electromagnetic waves, accelerate particles and produce emissions at various wavelengths, including bright UV auroral spots and tails in the atmosphere of Jupiter. In this work, we present 10 events where the Juno spacecraft observed both in situ and remotely the acceleration of electrons due to the interaction between the icy moon Europa and the magnetospheric environment. We characterize the properties of the accelerated electrons. In particular, we find that acceleration is maximum near the moon itself, and that two distinct families of electron distributions exist. Juno unambiguously observed 10 events of downward electron acceleration from Europa at various downtail separations with the moonPrecipitating energy fluxes decrease exponentially as a function of downtail distance from the moon, with an e‐folding of 7.4°Two types of electron distributions exist: non‐monotonic in the near tail and broadband in the far tail Juno unambiguously observed 10 events of downward electron acceleration from Europa at various downtail separations with the moon Precipitating energy fluxes decrease exponentially as a function of downtail distance from the moon, with an e‐folding of 7.4° Two types of electron distributions exist: non‐monotonic in the near tail and broadband in the far tail