The relationship between glutamate, dopamine, and cortical gray matter: A simultaneous PET-MR study

Prefrontal cortex has been shown to regulate striatal dopaminergic function via glutamatergic mechanisms in preclinical studies. Concurrent disruption of these systems is also often seen in neuropsychiatric disease. The simultaneous measurement of striatal dopamine signaling, cortical gray matter, and glutamate levels is therefore of major interest, but has not been previously reported. In the current study, twenty-eight healthy subjects underwent 2 simultaneous [11C]-( + )-PHNO PET-MRI scans, once after placebo and once after amphetamine in a double-blind randomized cross-over design, to measure striatal dopamine release, striatal dopamine receptor (D2/3R) availability, anterior cingulate glutamate+glutamine (Glx) levels, and cortical gray matter volumes at the same time. Voxel-based morphometry was used to investigate associations between neurochemical measures and gray matter volumes. Whole striatum D2/3R availability was positively associated with prefrontal cortex gray matter volume (pFWE corrected = 0.048). This relationship was mainly driven by associative receptor availability (pFWE corrected = 0.023). In addition, an interaction effect was observed between sensorimotor striatum D2/3R availability and anterior cingulate Glx, such that in individuals with greater anterior cingulate Glx concentrations, D2/3R availability was negatively associated with right frontal cortex gray matter volumes, while a positive D2/3R-gray matter association was observed in individuals with lower anterior cingulate Glx levels (pFWE corrected = 0.047). These results are consistent with the hypothesis that the prefrontal cortex is involved in regulation of striatal dopamine function. Furthermore, the observed associations raise the possibility that this regulation may be modulated by anterior cingulate glutamate concentrations

Vers une approche intégrée d’aide à la planification énergétique territoriale : application à la rénovation énergétique des bâtiments

The French residential and tertiary sectors account for about 45% of energy consumption and 20% of greenhouse gas emissions, constituting a large savings potential which is relatively easy to mobilise in comparison with other sectors such as transport or industry. This thesis develops a decision-aiding method for territories stakeholders willing to implement building energy retrofit measures. This method relies on a building stock modeling based on the enrichment of heterogeneous databases available to local decision-makers. An optimization problem of energy renovation measures activates levers at the building-level over the territory, turning dimensionality into a key issue this work. A meta-model of building heating energy consumption, adapted to this context, is constructed from a dynamic urban model. A dedicated characterisation of both thermal retrofit and energy systems is conducted, basing solutions on observations of the current French building context. Both modeling and optimization methods are finally applied to real territories, and used to conduct studies related to the energy transition context.Les secteurs résidentiel et tertiaire français représentent environ 45% de la consommation d'énergie et 20% des émissions de gaz à effet de serre, constituant un gisement d'économies important et relativement facilement mobilisable en comparaison à d'autres secteurs comme le transport ou l'industrie. Cette thèse développe une méthode d'aide à la décision territoriale pour la mise en oeuvre opérationnelle de la rénovation énergétique des bâtiments. Cette méthode repose sur une caractérisation des territoires basée sur l'enrichissement de bases de données hétérogènes et disponibles aux acteurs locaux. Un problème d'optimisation des mesures de rénovation énergétique permet d'actionner des leviers au niveau de chaque bâtiment du territoire, mettant la question de la dimensionnalité au cœur de ce travail. Un méta-modèle de la consommation énergétique de chauffage des bâtiments, adapté à ce contexte, est construit à partir d'un modèle dynamique urbain. Les solutions techniques de rénovation modélisées reposent sur une observation du contexte actuel français, et font d'objet d'une caractérisation technico-économique dédiée. Les méthodes de modélisation et d'optimisation sont enfin appliquées à différents territoires, et exploitées pour mener des études en lien avec le contexte de la transition énergétique

Towards an integrated energy planning decision-aiding at territory scale : application to the energy retrofit of buildings

Les secteurs résidentiel et tertiaire français représentent environ 45% de la consommation d'énergie et 20% des émissions de gaz à effet de serre, constituant un gisement d'économies important et relativement facilement mobilisable en comparaison à d'autres secteurs comme le transport ou l'industrie. Cette thèse développe une méthode d'aide à la décision territoriale pour la mise en oeuvre opérationnelle de la rénovation énergétique des bâtiments. Cette méthode repose sur une caractérisation des territoires basée sur l'enrichissement de bases de données hétérogènes et disponibles aux acteurs locaux. Un problème d'optimisation des mesures de rénovation énergétique permet d'actionner des leviers au niveau de chaque bâtiment du territoire, mettant la question de la dimensionnalité au cœur de ce travail. Un méta-modèle de la consommation énergétique de chauffage des bâtiments, adapté à ce contexte, est construit à partir d'un modèle dynamique urbain. Les solutions techniques de rénovation modélisées reposent sur une observation du contexte actuel français, et font d'objet d'une caractérisation technico-économique dédiée. Les méthodes de modélisation et d'optimisation sont enfin appliquées à différents territoires, et exploitées pour mener des études en lien avec le contexte de la transition énergétique.The French residential and tertiary sectors account for about 45% of energy consumption and 20% of greenhouse gas emissions, constituting a large savings potential which is relatively easy to mobilise in comparison with other sectors such as transport or industry. This thesis develops a decision-aiding method for territories stakeholders willing to implement building energy retrofit measures. This method relies on a building stock modeling based on the enrichment of heterogeneous databases available to local decision-makers. An optimization problem of energy renovation measures activates levers at the building-level over the territory, turning dimensionality into a key issue this work. A meta-model of building heating energy consumption, adapted to this context, is constructed from a dynamic urban model. A dedicated characterisation of both thermal retrofit and energy systems is conducted, basing solutions on observations of the current French building context. Both modeling and optimization methods are finally applied to real territories, and used to conduct studies related to the energy transition context

A generic GIS-based method for small Pumped Hydro Energy Storage (PHES) potential evaluation at large scale

International audienceThe increasing share of weather-dependent renewable energies in power systems creates a need for energy storage technologies to reduce the impacts of variable production. The most mature technology to store energy on the grid remains Pumped Hydro Energy Storage (PHES). The potential of high-energy sites has already been assessed in Europe by the EU JRC, considering mostly dams and reservoirs from global European databases which include only massive water bodies. This paper focuses on estimating the potential for small-PHES, proven to have lower environmental impact and an positive impact on grid balance and reliability. A generic method is designed, able to evaluate a global PHES storage capacity at large scale. It considers both existing lakes and natural depressions suitable to be filled for PHES purposes. The volume of filled lakes is estimated using the surrounding topography. The method is organized so that the “heavy” calculations, i.e. sink detection, volume evaluation, constraints verification, etc. are run only once. Consequently, the actual potential estimation phase only includes fast calculations and can be integrated in a loop for carrying out a sensitivity analysis. The proposed method is then applied considering France as a test case. Suitable environmental, land-use and structural constraints are applied to eliminate irrelevant sites. The analysis leads to an estimated value of the small-PHES potential in France, which ranges from 14 GWh when only existing lakes are considered to 33 GWh when lakes and depressions are considered. These estimations represent respectively 8% and 18% of the current hydro storage capacity in France. Thanks to a global sensitivity analysis, factors like the maximum distance between lakes, the maximum altitude of the sites, and the distance to the electrical grid are shown to have the most influence on the global evaluated potential, which is further sensitized. Lastly, another application is suggested that makes it possible to select the connections to be built first within a restricted area, based on a cost-per-energy-like approach. It uses the connections between reservoirs detected at large geographical scale

An address-matching algorithm for household-scale databases to enhance electricity demand characterization

International audienceThis paper participates in the challenging data science opportunity offered by the growing number of databases made available to public institutions. It presents an innovative method to match household-scale databases using address information. The developed algorithm authorizes different matching qualities, depending on the reliability of the link between the paired elements. This work was carried out in collaboration with the French DSO Enedis, which provided valuable customer information that was matched with a national database describing dwellings. The matching algorithm performances are analyzed, and adjustments are proposed to improve the matching quality in urban, suburban and rural contexts. Lastly, two basic characterization analyses were made to highlight the potential of these consolidated databases

Evolution of electrical distribution grid sizing considering self-consumption of local renewable production

International audienceIn the last decades, renewable energy sources have been increasing their shares in the world energy market. In addition to the ecological benefits, this trend can have adjunct benefits, for example for distribution system operators: a gain in their grid sizing. Indeed, installation of decentralized production, when used in a self-consumption approach, can lead to reduction of the consumption peaks. This work is willing to quantify what grid sizing reduction a distribution system operator can expect, knowing the renewable energies penetration rate on a MV feeder. To do so, a description of the actual sizing strategy is first described. Estimation of electricity demand is performed using a bottom-up simulation method while photovoltaics and wind power production are evaluated with reanalysis data coupled with a new method to inject variability to the smooth curves. This procedure leads to a new sizing power which can be used, guaranteeing an equivalent quality of supply for consumers. For the tested MV feeders, a maximum reduction of about 4 % of the sizing power is observed. Lastly, an analysis of the under-sizing risk is carried out, characterizing the error in the new sizing power estimation with the number of scenarios taken into account

Joint optimization of building-envelope and heating-system retrofits at territory scale to enhance decision-aiding

International audienceReduction of energy consumption in the building sector has been identified as a major instrument to tackle global climate change and improve sustainability. In this paper, we propose a methodology to address a retrofit planning problem at a community level, with a building resolution. The resulting tool helps local decision-makers identify pertinent actions to improve the environmental behavior of their territories. Two building retrofit levers are considered, namely envelope insulation and heating systems replacement. Retrofit planning is treated here as a single-objective optimization problem aimed at reducing the total costs of retrofit actions by minimizing their net present value. A multidimensional multiple-choice knapsack problem formulation is proposed through the adoption of adequate decision variables. It suitably balances the complexity induced by the large number of potential retrofit action combinations and the number of variables in the problem and permits a linear formulation. An optimization of virtual building stocks is performed to highlight the developed model's capacity to tackle large problems (5,000 buildings) in a few minutes. Finally, three analyses finally are led on a real case-study territory, featuring both appropriate retrofit solutions and building stock information. Long-term evaluation of retrofit strategies over the short-term results in an additional 10% reduction of energy consumption and greenhouse gases emissions and encourages thermal insulation. When targeting a 40% reduction in energy demand, retrofit costs ranging from 20 to 800e/m 2 are observed. Finally, the developed method was used to draw a CO 2 abatement cost curve at territory level. A 70% reduction of emissions can be achieved with costs under 50 e/tCO 2 e

Techno-economic evaluation and resource assessment of hydrogen production through offshore wind farms: a European perspective

Hydrogen demand is expected to radically increase in the upcoming years as it is a key lever of decarbonization and offshore wind has been identified as a credible energy source to power electrolyzers. Onshore, centralized offshore and decentralized offshore electrolysis are considered in this paper, for which a detailed cost modeling is carried out. A geospatial analysis leads to a resource assessment at European scale based on the levelized cost of hydrogen (LCOH), where both the energy production potential and technical and environmental constraints are considered. The results reveal a massive resource in European seas, with LCOH decreasing from 4.5-7.5 €/kg in 2020 to 1.5-3.0 €/kg in 2050 due to the reduced costs of wind turbines and electrolyzers. A significant amount of green hydrogen-more than 1,000 TWh-could be produced at less than 3.0 €/kg in 2030 and 2.0 €/kg in 2050, making it competitive with grey hydrogen. In 2030, the mapping identifies a valuable 200 TWh resource where offshore wind-to-hydrogen projects offer a much-lower LCOH than their wind-to-power counterparts. The results of the resource assessment are detailed at country level, offering a valuable tool for energy modelers and local stakeholders. Finally, a detailed analysis of costs identifies offshore electrolysis as becoming more relevant over time: in 2020, offshore electrolysis is preferred for far-from-shore and deep-sea locations only while being located closer to shore in 2030 (over 100 km). In 2050, onshore electrolysis relevance is limited to locations close-to-shore in shallow waters

The relationship between glutamate, dopamine, and cortical gray matter

Prefrontal cortex has been shown to regulate striatal dopaminergic function via glutamatergic mechanisms in preclinical studies. Concurrent disruption of these systems is also often seen in neuropsychiatric disease. The simultaneous measurement of striatal dopamine signaling, cortical gray matter, and glutamate levels is therefore of major interest, but has not been previously reported. In the current study, twenty-eight healthy subjects underwent 2 simultaneous [11C]-( + )-PHNO PET-MRI scans, once after placebo and once after amphetamine in a double-blind randomized cross-over design, to measure striatal dopamine release, striatal dopamine receptor (D2/3R) availability, anterior cingulate glutamate+glutamine (Glx) levels, and cortical gray matter volumes at the same time. Voxel-based morphometry was used to investigate associations between neurochemical measures and gray matter volumes. Whole striatum D2/3R availability was positively associated with prefrontal cortex gray matter volume (pFWE corrected = 0.048). This relationship was mainly driven by associative receptor availability (pFWE corrected = 0.023). In addition, an interaction effect was observed between sensorimotor striatum D2/3R availability and anterior cingulate Glx, such that in individuals with greater anterior cingulate Glx concentrations, D2/3R availability was negatively associated with right frontal cortex gray matter volumes, while a positive D2/3R-gray matter association was observed in individuals with lower anterior cingulate Glx levels (pFWE corrected = 0.047). These results are consistent with the hypothesis that the prefrontal cortex is involved in regulation of striatal dopamine function. Furthermore, the observed associations raise the possibility that this regulation may be modulated by anterior cingulate glutamate concentrations