État des lieux et perspectives de la prise en charge du syndrome d'hypoplasie du coeur gauche et de ses malformations constitutives au CHUV

Objectifs L’objectif principal de ce travail est d’établir un état des lieux de la prise en charge des enfants atteints d’un syndrome d’hypoplasie du coeur gauche (SHCG) ou de ses malformations constitutives entre les années 1990 et 2018 au CHUV. Les objectifs secondaires portent sur les cas de sténoses de la valve aortique diagnostiqués lors des échocardiographies prénatales, et pour lesquels une évolution vers un SHCG était suspectée. Pour chacun de ces foetus nous déterminerons les scores de Boston afin d’identifier les cas qui auraient satisfait les conditions nécessaires pour être candidats à une dilatation in-utero de la valve aortique, et auraient donc pu être référés dans un centre pratiquant ce type d’intervention. Nous nous enquerrons également du devenir circulatoire (univentriculaire vs. biventriculaire) de tous ces foetus en l’absence d’intervention inutero, et porterons un regard critique sur la concordance de cette issue avec les critères visant à prédire une évolution vers un SHCG. Nous espérons ainsi nous faire une idée de la fiabilité de ces critères appliqués à notre population, et donc évaluer la pertinence de les utiliser à l’avenir afin de prédire l’évolution inutero des foetus avec un diagnostic prénatal de sténose de la valve aortique. Méthodologie Cette étude est une étude rétrospective des dossiers informatiques de tous les foetus et nouveau-nés pris en charge au CHUV entre les années 1990 et 2018 pour un diagnostic de SHCG ou l’une de ses malformations constitutives. Les cas inclus ont été identifiés au sein des bases de données de cathétérisme cardiaque, de chirurgie cardiaque pédiatrique et d’échocardiographie foetale. In fine, 46 patients ont été inclus dans l’étude concernant la prise en charge post-natale et 12 patients ont été retenus pour l’étude des aspects anténataux. Résultats et conclusion L’état des lieux de prise en charge des enfants atteints d’un SHCG ou de ses malformations constitutives entre les années 1990 et 2018 au CHUV nous a permis de mettre en exergue le fait que la prise en charge au CHUV est sensiblement conforme aux données trouvées dans la littérature. En effet, que ce soit en terme d’interventions réalisées (intervention de Norwood avec un shunt selon Sano (70%) ou Blalock modifié (30%), puis intervention de Glenn, et enfin complétion du Fontan), de l’âge médian auquel elles ont été réalisées (respectivement 8 jours, 5 mois et 2,4 ans) ou de leurs complications, nous constatons que nos résultats ne divergent pas de ceux mentionnés dans la littérature. Nous avons évalué la fiabilité de critères visant à prédire une évolution vers un SHCG appliqués à notre population et nous sommes arrivés à la conclusion que, avec une sensibilité de 83% et une spécificité de 83%, une valeur prédictive positive de 83% et une valeur prédictive négative de 83%, ainsi que des rapports de vraisemblance de 5,00 en présence d’un score positif et de 0,20 en présence d’un score négatif, ces critères ne sont pas suffisamment fiables pour être utilisés comme seul moyen de prédiction de l’évolution in-utero des foetus avec un diagnostic prénatal de sténose de la valve aortique. Dans notre cohorte de cas prénataux, le score de Boston de tous les foetus aurait été défavorable pour une issue biventriculaire après une intervention cardiaque foetale (score <4). De ce fait, bien que la validité de ce score appliqué à notre population reste encore à confirmer, aucun de ces foetus n’aurait été éligible pour une intervention de dilatation de la valve aortique in-utero

Aṣṛaṛfi

Ce nom est attesté dans un récit autobiographique en chleuh (berbère du Sud marocain), dicté à P. Galand-Pernet, en 1974, par Abdelkader ben Abdallah, chanteur professionnel originaire des Aštukn (Chtouka) de l’Anti-Atlas, aṣṛaṛfi représente l’arabe dialectal sṛāṛfi, singulier formé sur un schème de pluriel (Cohen 1975, p. 179) à partir de la racine ṢRF. Le sens premier paraît être, en arabe, celui de « changeur » (Tedjini 1942, p. 137 ; Ferré, p. 213 ;Cohen 1975, p. 179), en accord avec le v..

Characterizing the limitations to the coupling between Saturn's ionosphere and middle magnetosphere

Observations of Saturn's ultraviolet and infrared aurora show structures that, when traced along the planetary magnetic field, map to the inner, middle, and outer magnetosphere. From low to high latitudes the structures seen in the UV are the Enceladus footprint, which maps to an equatorial radius of 4 R S (Saturn radii); a diffuse emission that maps to a broad equatorial region from 4-11 RS on the nightside; and a bright ring of emission that maps to ∼15 RS. With the exception of the Enceladus spot, the magnetospheric drivers for these auroral emissions are not yet fully understood. We apply a 1D spatial, 2D velocity space Vlasov solver to flux tubes mapping from equatorial radii of 4, 6, 9, and 13 RS to Saturn's southern atmosphere. The aim is to globally characterize the field-aligned potential structure and plasma density profiles. The ionospheric properties - the field-aligned current densities at the ionospheric boundary, energy intensity profiles and fluxes of the electrons precipitating into the ionosphere - are also determined. We then couple our results to an ionospheric model to calculate the Pedersen conductances at the foot of the relevant flux tubes. We find that for a zero net potential drop between the ionosphere and magnetosphere, there exists a sharp potential drop at ∼1.5 RS along the magnetic field line as measured from the planetary center. The strength of this potential drop is approximately equal to that of the ambipolar potential resulting from the centrifugal confinement of the heavy, cold magnetospheric ion population. We also find that the ionospheric properties respond to changes in the magnetospheric plasma population, which are reflected in the nature of the precipitating electron population. For the flux tube mapping to 9 RS (-70), the incident electron energy flux into the ionosphere resulting from a magnetospheric plasma population with a small fraction of hot electrons is an order of magnitude less than that inferred from observations, implying that significant high-latitude field-aligned potentials (up to 1.5 keV) may exist in the saturnian magnetosphere. Calculated ionospheric Pedersen conductances range from 3.0-18.9 mho, and are thus not expected to limit the currents flowing between the ionosphere and magnetosphere

Current-voltage relation for the Saturnian system

Saturn's magnetosphere is populated by plasma created from neutrals ejected by the moon Enceladus. These neutrals are ionized and picked up by the planetary magnetic field requiring large amounts of angular momentum to be transferred from Saturn's upper atmosphere to the magnetospheric plasma. The resulting upward currents that supply this angular momentum are associated with electrons, which travel toward the planetary atmosphere. At high magnetic latitudes along the flux tube, parallel electric fields may develop to enhance the field-aligned current density flowing between the two regions. We show that, similar to the Jovian system, the current-voltage relation in the Saturnian system must be evaluated at the top of the acceleration region, which occurs at ~1.5 RS along the magnetic field line as measured from the center of the planet. Owing to the large abundance of protons in the Saturnian system, cold electrons carry the majority of the field-aligned current for net potential drops less than 500 V. For the flux tube intersecting the equatorial plane at 4 RS, field-aligned potentials of 50-130 V are consistent with the energy fluxes inferred from the Enceladus emission. In the middle magnetosphere, field-aligned potentials of ∼1.5 kV produce ionospheric electron energy fluxes of 0.3 mW/m2 when hot electrons comprise 0.3% of the magnetospheric electron population. Key Points Current-voltage relation must be evaluated at high magnetic latitudes. Cold electrons contribute strongly to field-aligned current density. Full Knight (1973) current-voltage relation must be applied to Saturnian system

Optimising a nonlinear utility function in multi-objective integer programming

In this paper we develop an algorithm to optimise a nonlinear utility function of multiple objectives over the integer efficient set. Our approach is based on identifying and updating bounds on the individual objectives as well as the optimal utility value. This is done using already known solutions, linear programming relaxations, utility function inversion, and integer programming. We develop a general optimisation algorithm for use with k objectives, and we illustrate our approach using a tri-objective integer programming problem.Comment: 11 pages, 2 tables; v3: minor revisions, to appear in Journal of Global Optimizatio

Response of Saturn's auroral ionosphere to electron precipitation: Electron density, electron temperature, and electrical conductivity

In the high-latitude regions of Saturn, the ionosphere is strongly coupled to the magnetosphere through the exchange of energy. The influx of energetic particles from Saturn's magnetosphere enhances the ionospheric densities and temperatures, affects the electrodynamical properties of the ionosphere, and contributes to the heating of the thermosphere. It is therefore critical to accurately model the energy deposition of these magnetospheric particles in the upper atmosphere in order to evaluate key ionospheric quantities of the coupled magnetosphere-ionosphere system. We present comprehensive results of ionospheric calculations in the auroral regions of Saturn using our Saturn Thermosphere-Ionosphere Model (STIM). We focus on solar minimum conditions during equinox. The atmospheric conditions are derived from the STIM 3-D General Circulation Model. The ionospheric component is self-consistently coupled to the solar and auroral energy deposition component. The precipitating electrons are assumed to have a Maxwellian distribution in energy with a mean energy E-m and an energy flux Q(0). In the presence of hard electron precipitation (1 < E-m <= 20 keV) with Q(0) > 0.04 mW m(-2), the ionospheric conductances are found to be proportional to the square root of the energy flux, but the response of the ionosphere is not instantaneous and a time delay needs to be applied to Q(0) when estimating the conductances. In the presence of soft electron precipitation (E-m < 500 eV) with Q(0) <= 0.2 mW m(-2), the ionospheric conductances at noon are found to be primarily driven by the Sun. However, soft auroral electrons are efficient at increasing the ionospheric total electron content and at heating the thermal electron population

Magnetosphere-atmosphere coupling at Saturn: 1-Response of thermosphere and ionosphere to steady state polar forcing

We present comprehensive calculations of the steady state response of Saturn’s coupled thermosphere–ionosphere to forcing by solar radiation, magnetospheric energetic electron precipitation and high latitude electric fields caused by sub-corotation of magnetospheric plasma. Significant additions to the physical processes calculated in our Saturn Thermosphere Ionosphere General Circulation Model (STIM–GCM) include the comprehensive and self-consistent treatment of neutral–ion dynamical coupling and the use of self-consistently calculated rates of plasma production from incident energetic electrons. Our simulations successfully reproduce the observed high latitude temperatures as well as the latitudinal variations of ionospheric peak electron densities that have been observed by the Cassini Radio Science Subsystem experiment (RSS). We find magnetospheric energy deposition to strongly control the flow of mass and energy in the high and mid-latitude thermosphere and thermospheric dynamics to play a crucial role in driving this flow, highlighting the importance of including dynamics in any high latitude energy balance studies on Saturn and other Gas Giants. By relating observed View the MathML sourceH3+ column emissions and temperatures to the same quantities inferred from simulated atmosphere profiles we identify a potential method of better constraining the still unknown abundance of vibrationally excited H2 which strongly affects the View the MathML sourceH3+ densities. Our calculations also suggest that local time variability in View the MathML sourceH3+ column emission flux may be largely driven by local time changes of View the MathML sourceH3+ densities rather than temperatures. By exploring the parameter space of possible high latitude electric field strengths and incident energetic electron fluxes, we determine the response of thermospheric polar temperatures to a range of these magnetospheric forcing parameters, illustrating that 10 keV electron fluxes of 0.1–1.2 mW m−2 in combination with electric field strengths of 80–100 mV m−1 produce View the MathML sourceH3+ emissions consistent with observations. Our calculations highlight the importance of considering thermospheric temperatures as one of the constraints when examining the state of Saturn’s magnetosphere and its coupling to the upper atmosphere

Optimization of macrostructure of nickel-based alloys castings

Tato diplomová práce se zabývá ovlivňováním struktury odlitků niklové superslitiny Inconel 713LC silovými účinky aplikovanými na taveninu prostřednictvím vibrace a rotace při krystalizaci. Pro tuto práci byly odlity tři zkušební odlitky s různými podmínkami tuhnutí, pro zkoumání struktury zrn ovlivněné silovým působením kovu. Cílem práce bylo porovnat jednotlivé makrostruktury a mikrostruktury odlitků a následně zjistit závislost zjemnění zrna na mechanických vlastnostech. Po lomu zkušebních tyčí byly metodami světelné a elektronové mikroskopie analyzovány jednotlivé změny ve struktuře.This diploma thesis is focusing on possibilities of influencing casting’s structure of nickel superalloy Inconel 713LC by force effects caused by vibration and rotation during crystallization. In this research were cast three test castings of turbine wheels with different solidification conditions that have affected the size and distribution of the grains. The aim was to compare the different microstructure and macrostructure of castings and then compare the dependence of grain refinement on mechanical properties. Changes in the structure were analyzed by means of light and electron microscopy methods after the fracture of test bars.