82 research outputs found
Advances in pulmonary hypertension diagnosis and risk stratification.
editorial reviewedPulmonary hypertension (PH) is a common clinical condition linked to chronic cardiopulmonary illnesses. It must be distinguished from pulmonary arterial hypertension (PAH), a rare disease characterized by a specific involvement of the pulmonary arterial bed. An early diagnosis and accurate classification by a multidisciplinary team are necessary for a multimodal and individualized therapy approach. This article aims to provide a summary of the most recent ESC/ERS recommendations published in 2022.L’hypertension pulmonaire (HTP) est une entité clinique fréquemment retrouvée chez les patients atteints d’affections cardio-pulmonaires chroniques. Elle est à différentier de l’hypertension artérielle pulmonaire (HTAP) qui est, quant à elle, une maladie rare caractérisée par une atteinte spécifique du lit artériel pulmonaire. Une identification précoce et une classification correcte, en équipe pluridisciplinaire, sont primordiales pour une prise en charge thérapeutique multimodale et personnalisée. Cet article a pour but de résumer, de façon pratique, les dernières recommandations des sociétés européennes de cardiologie (ESC) et de pneumologie (ERS) publiées en 2022
VARIATIONS DEPUIS 10000 ANS DE LA REPARTITION ET DE LA PRODUCTIVITE DES FORETS D'ALTITUDE DANS LES ALPES ET LE JURA ET SIMULATION DES CHANGEMENTS FUTURS
Ce travail repose sur les charbons de bois enfouis dans les sols et les autres macrorestes ont été datés par 14C et identifiés botaniquement, et pour un site particulier (lac Cristol), sur les analyses de pollens, d'insectes, de macro-restes végétaux, charbons de bois et tronc d'arbres ont été combinés en une « approche multi-proxy » afin de mieux comprendre les variations de la forêt de montagne en réponse aux changements climatiques globaux et à l'activité anthropique. Les variations de la limite de la forêt sont de plus de 500 m durant l'Holocène. La période la plus chaude semble avoir été 9000-8000 ans cal B.P. (années calendaires avant le présent). Les hauts niveaux lacustres du début et de la fin de l'Holocène sont de natures en fait assez différentes. Au début de l'Holocène ils sont principalement dus à une évapotranspiration plus faible, et à la fin de l'Holocène à des précipitations plus élevées. L'ensemble de ces informations a permis de tester un modèle de végétation (Biome3) par une utilisation en mode inverse et à essayer de prédire l'évolution de la végétation. Un doublement de CO2 permet à la végétation d'évoluer vers des conditions plus tempérées. Une « forêt mixte tempérée », pourra devenir une forêt décidue tempérée grâce à des hivers nettement plus doux et à une meilleure efficacité dans l'utilisation de l'eau en été. Ces sites d'altitude ont connu une telle végétation entre 9000 et 8000 ans cal B.P
Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry
Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase
Impact of a tariff based heating load control on energy, comfort and environment: a parametric study in residential and office buildings
International audienceIn the perspective of systematic deployment of smart meters and smart HVAC systems, energy price is a possible incentive to automatically shift consumption from a constrained time-slot (e.g. around 7:00 pm) to a relaxed one (in the night). Such load shedding mechanisms are already in place in France for domestic hot water usage and are likely to be broadened to heating systems. This paper investigates the impact of an automatic tariff-based heating load control on the energy consumption, load curve, thermal comfort and environmental impact for the end-user. To achieve this study a method has been developed to assess the performance of a control strategy associated with a tariff signal through simulations. This method has been applied to different control strategies and tariff signals for several combinations of buildings and heating control systems. This work focuses on the existing building stock - with its main variations in terms of insulation, typology or heating control under different climatic conditions - while capturing the fundamental of building thermal response with the help of thermal simulation. This paper explains the methodology and the parametric study and shows that load shedding has limited advantages in terms of spared energy and comfort but can have a real effect on the heating load curve. Due to its systematic coverage this work aims at completing the current literature focused either on one technology or on control strategies
Impact of a tariff based heating load control on energy, comfort and environment: a parametric study in residential and office buildings
International audienceIn the perspective of systematic deployment of smart meters and smart HVAC systems, energy price is a possible incentive to automatically shift consumption from a constrained time-slot (e.g. around 7:00 pm) to a relaxed one (in the night). Such load shedding mechanisms are already in place in France for domestic hot water usage and are likely to be broadened to heating systems. This paper investigates the impact of an automatic tariff-based heating load control on the energy consumption, load curve, thermal comfort and environmental impact for the end-user. To achieve this study a method has been developed to assess the performance of a control strategy associated with a tariff signal through simulations. This method has been applied to different control strategies and tariff signals for several combinations of buildings and heating control systems. This work focuses on the existing building stock - with its main variations in terms of insulation, typology or heating control under different climatic conditions - while capturing the fundamental of building thermal response with the help of thermal simulation. This paper explains the methodology and the parametric study and shows that load shedding has limited advantages in terms of spared energy and comfort but can have a real effect on the heating load curve. Due to its systematic coverage this work aims at completing the current literature focused either on one technology or on control strategies
Optimal power flow of a distribution system based on increasingly tight cutting planes added to a second order cone relaxation
International audienceConvex relaxations of the optimal power flow (OPF) problem have received a lot of attention in the recent past. In this work, we focus on a second-order cone (SOC) relaxation applied to an OPF based on a branch flow model of a radial and balanced distribution system. We start by examining various sets of conditions ensuring the exactitude of such a relaxation, which is the main focus of the existing literature. In particular, we observe that these sets always include a requirement on the objective to be a minimization of a function increasing with the branch flow apparent powers. We consider this hypothesis to be at odds with what is to be expected of an active distribution system and demonstrate in specific case studies its counterproductive impact. We continue by introducing an objective function allowing distributed generations and storages (DGS) to take advantage of the benefits they bring to the power system as a whole. As this entails the possibility for the relaxation not to be exact, we describe and prove the theoretical convergence to optimality of an algorithm consisting in adding an increasingly tight linear cut to the SOC relaxation. In order to allow the attainment of a solution satisfying the network constraints in a finite number of steps, we continue by introducing a tailored termination criterion. Afterwards, we investigate the ability of our algorithm to obtain a satisfactory solution on several case studies, spanning various network sizes, number of nodes equipped with DGs and their level of penetration. We then conclude on the benefits brought about by this approach and reflect on its limits and the opportunities for further improvements
Planning-oriented yearly simulation of energy storage operation in distribution system for profit maximization, voltage regulation and reserve provisionning
International audienceThe connection of generation units at the distribution level is expected to increase significantly in the future. This phenomenon will have impacts on the planning and operation of the electric system, both at the local (e.g. appearance of reverse power flows) and global (e.g. modification of the supply-demand equilibrium and of the reserve provisioning capabilities) level. In this context, storage devices are increasingly seen as a possible way to mitigate these impacts, with the caveat -compared to alternative solutionsthat their versatility comes with high investment costs. Consequently, it is of the utmost importance to make sure that the full capabilities of these storage devices are put to use. Following this line of thought, this paper presents an algorithm suitable for planning purposes that simulates the yearly operation of distributed energy storage units connected at the medium voltage level to maximize the profit drawn from market operation while respecting voltage and reserve requirement constraints
Iterative linear cuts strenghtening the second-order cone relaxation of the distribution system optimal power flow problem
International audienceWe present a novel iterative algorithm to solve the distribution system optimal power flow problem over a radial network. Our methodology makes use of a widely studied second order cone relaxation applied to the branch flow model of a radial network. Several types of conditions have been established under which this relaxation is exact and we focus here on the situations where this is not the case. To overcome this difficulty, we propose to add increasingly tight linear cuts to the second-order cone problem until a physically meaningful solution is obtained. We apply this technique to a sample system taken from the literature and compare the results with a traditional nonlinear solver
A criticality criterion to decrease the computational burden in multistage distribution system optimal power flow
International audienceAs the penetration of distributed generation and storage means in the distribution system is expected to increase, new tools for its planning and operation will be needed and optimal power flow calculations will certainly play a prominent role. However, obstacles have to be overcome before these can be deployed, among which their computational burden is of particular concern. Consequently, we introduce here the use of a criticality criterion aimed at detecting for which time steps the voltage constraints need to be evaluated. We apply the methodology to a distribution system extracted from the literature and discuss the influence of various parameters on the validity of the methodology and the computational gains expected
Thermal behaviour of rooftop BIPV systems: an experimental approach
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