L'économie doit être pensée pour permettre (et accélérer) la transition

L’économie n’est pas une science exacte régie par des lois naturelles, mais bien une science humaine, façonnée par des théoriciens. D’autres courants que ceux qui ont prévalu jusqu’à maintenant gagnent heureusement en visibilité. Ils cherchent à tenir compte de la réalité en intégrant les limites planétaires dans leur modèle, ou le fait que le bien-être ne se limite pas qu’au calcul du PIB. D’autres types de capitaux devraient être pris en compte par le modèle économique : la santé, le bien-être, la biodiversité, etc. Les crises se succèdent, elles sont devenues la norme. Faire le dos rond n’y changera rien, et le marché n’apportera pas la solution. L’État doit intervenir sur plusieurs axes afin d’orienter l’économie et accélérer la transition. Les acteurs impliqués, des entreprises aux consommateurs, sont nombreux, de même que les secteurs de l’économie sur lesquels mettre l’accent pour viser le « moins mais mieux ».Cite as: Michaud Gigon, Sophie (2023) : L'économie doit être pensée pour permettre (et accélérer) la transition, in : Académie suisse des sciences humaines et sociales : Wege zu einem nachhaltigen Konsum | Vers une consommation durable, (Swiss Academies Communications, 18, 5), pp. 85-96. https://doi.org/10.5281/zenodo.815858

Les effets du tabagisme dans l'ischémie et la néovascularisation

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Expérimentation d'une nouvelle méthode culturale sur billons (BED) pour produire des pommes de terres de semences destinées à l'exportation

Affiche présentée dans le cadre du Colloque de l'ARC, «Des racines et des ailes pour la recherche collégiale», dans le cadre du 85e Congrès de l’Acfas, Université McGill, Montréal, les 8 et 9 mai 2017.Pour le marché de l’exportation, la taille de la semence de pomme de terre est un important critère de qualité : un tubercule entier mesurant entre 38 et 55 mm est recherché. L’objectif du projet était d’évaluer l’impact de la taille et de la densité de plantation sur la taille des tubercules produits. Deux variétés, Chieftain et Harmony, ont été expérimentées avec deux distances entre les rangs, trois distances sur le rang et deux grosseurs de plantons. La production en plateforme a été comparée à la production traditionnelle en rang unique. Pour la variété Harmony, la production de tubercules de 38 à 55 mm a été significativement supérieure avec une distance entre les rangs de 40 cm, une distance sur le rang de 20 cm et un planton de 100 g. Le système en plateforme a généré un rendement total supérieur et a produit davantage de tubercules de la taille recherchée. Pour la variété Chieftain, la production de tubercules de 38 à 55 mm a été considérablement plus élevée avec une distance entre les rangs de 40 cm, des distances sur le rang de 20 et 25 cm et un planton de 100 g. Le projet a démontré que le système en plateforme est plus performant pour la production de semences de la taille recherchée pour l’exportation, que la densité de plantation, tant entre les rangs que sur le rang, a un impact sur la taille des tubercules produits, et enfin, que les variétés répondent différemment aux traitements de densité de plantation

Coordination of a bifunctional ligand to a rhodium(III) dimethyl complex : Lewis acidity enhancement by chelation

The addition of the ambiphilic compound (Me2PCH2AlMe2)2 (1) to Cp*RhMe2(DMSO) (DMSO ) dimethylsulfoxide) (2) gives Cp*RhMe2(PMe2CH2AlMe2‚DMSO) (3‚DMSO). The addition of Lewis acids (LA) such as La(dbm)3 (dbm ) dibenzoylmethane) and AlMe3 to a solution of complex 3‚DMSO gives a competition reaction that results in the formation of LA‚DMSO and Cp*RhMe2(PMe2CH2AlMe2) (3). When heated to 40 °C, complex 3 ionizes to a putative zwitterionic species, Cp*Rh+Me(PMe2CH2AlMe3 -) (3′), which is converted to [Cp*Rh(Me)(µ2 -η2 -Me2PCH2)]2 (4) irreversibly. Spin saturation transfer experiments demonstrated that the rate of the methyl abstraction by the alane moiety was 0.76 ( 0.09 s-1 , while the rate of abstraction of the methyl in Cp*RhMe2(PMe3) by AlMe3 was 0.10 ( 0.02 s-1 . The zwitterionic species 3′ could be trapped in solution by addition of PMe3 to afford both Cp*Rh+Me(PMe3)(Me2- PCH2AlMe3 -) (5) and [Cp*Rh+Me(PMe3)(Me2PCH2AlMe2)]AlMe4 - (6). When compound 1 was added to complex 3′, the formation of the zwitterionic complex Cp*Rh+Me(η2 -Me2PCH2Al-Me2CH2PMe2) (7) was observed

alpha,omega-Bis(trialkoxysilyl) difunctionalized polycyclooctenes from ruthenium-catalyzed chain-transfer ring-opening metathesis polymerization

International audienceThe ring-opening metathesis polymerization/cross-metathesis (ROMP/CM) of cyclooctene (COE) using bis(trialkoxysilyl)alkenes as chain-transfer agents (CTAs) and Ru catalysts to afford difunctionalized polyolefins is reported. The formation of alpha,omega-bis(trialkoxysilyl) telechelic polycycloolefins (DF) with controlled molar mass values takes place quite selectively (>90 wt%), along with minor amounts of cyclic non-functionalized polymers (CNF), as evidenced by NMR, MALDI-ToF MS, SEC analyses and fractionation experiments. The nature of the CTA and catalyst influenced much the efficiency and selectivity of the reaction. (MeO)(3)SiCH2CH=CHCH2Si(OMe)(3) (2) and (MeO)(3)Si(CH2)(3)NHC(O)OCH2CH=CHCH2OC(O)NH (CH2)(3)Si(OMe)(3) (5) proved to be the most efficient CTAs in terms of reactivity, catalyst productivity and selectivity towards DF. Diurethane CTA 5 is easily prepared, and can also be conveniently generated in situ during the ROMP/CM. Grubbs' 2nd-generation catalyst (G2) and Hoveyda-Grubbs's catalyst (HG2) afforded the best compromise in terms of selectivity and productivity, with turnover numbers of up to 95 000 mol(COE) mol(Ru)(-1) and 5000 mol(CTA) mol(Ru)(-1)

High Performance Pre-Computing: Prototype Application to a Coastal Flooding Decision Tool

International audienceAfter defining the High Performance Pre- Computing --referred as HPPC-- concept, the aim of the present study is to develop a prototype whether to approve or not the benefits of this concept. Our application case tries to answer the geophysical issue of coastal flooding. This is an example of an alert system based on the HPPC architecture, thus on pre-computed scenarios. The prototype provides the scientists with an ergonomic and on-demand tool allowing the run of scenarios of any implemented numerical models. These runs are available through a web application which submits the corresponding jobs on the remote french public cluster of HPC@LR. In this study we simulate the waves propagation over a Mediterranean grid using the wave model WaveWatch III⃝R . A reference simulation using usual conditions is approximated using the k-NN algorithm over 12, 98 and then 980 pre-computed scenarios. This simple experiment demonstrates how useful the pre-computing of scenarios is for alert systems as far as enough and relevant scenarios are pre-computed. This is the reason why searches continue in each critical points of the HPPC architecture such as the design of experiment, the approximation of the results by meta-models and the research of the closest scenarios in this big data context

α,ω-Di(glycerol carbonate) telechelic polyesters and polyolefins as precursors to polyhydroxyurethanes: an isocyanate-free approach

International audienceα,ω-Di(glycerol carbonate) telechelic poly(propylene glycol) (PPG), poly(ethylene glycol) (PEG), poly(ester ether) (PEE), and poly(butadiene) (PBD) have been synthesized through chemical modification of the corresponding α,ω-dihydroxy telechelic polymers (PPG-OH2, PEG-OH2, PEE-OH2 and PBD-OH2, respectively). Tosylation of the polymer diols with 4-tosylmethyl-1,3-dioxolan-2-one (GC-OTs) afforded, in high yields, the desired PPG, PEG, PEE and PBD end-capped at both termini with a five-membered ring cyclic glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one, GC). The GC-functionalization of the polymers at both chain-ends has been confirmed by NMR (1H, 13C, 1D and 2D) and FTIR spectroscopies. Using PPG-GC2 to demonstrate the concept, the corresponding polyhydroxyurethanes (PHUs/non-isocyanate polyurethanes (NIPUs)) have been subsequently prepared following a non-isocyanate method upon ring-opening catalyst-free polyaddition of the PPG-GC2 with JEFFAMINEs (Mn = 230-2000 g mol−1). The effect of various additives introduced during the polyaddition reaction has been studied at different temperatures. In particular, addition of LiBr (5 mol%) to the reaction medium was found to slightly promote the cyclocarbonate/amine reaction. The polymerization process was supported by FTIR and SEC analyses

Ring-opening metathesis polymerization of cyclooctene derivatives with chain transfer agents derived from glycerol carbonate

International audienceThe synthesis of a variety of mono- and di-(glycerol carbonate) telechelic polyolefins has been achieved upon ruthenium-catalyzed ring-opening metathesis polymerization (ROMP) of cyclooctene (COE) derivatives in the presence of a vinyl or acryloyl derivative of glycerol carbonate (GC) acting as a chain-transfer agent (CTA). Reaction monitoring based on SEC and 1H NMR analyses suggested that the ROMP proceeds through the formation of first the α-GC,ω-vinyl-poly(cyclooctene) (PCOE) intermediate, which eventually evolves over time into the α,ω-di(GC)-PCOE. The nature of the solvent was shown to have a significant impact on both the reaction rates and the eventual selectivity for the mono-/di-telechelic PCOE. ROMP of 3-alkyl (methyl, ethyl, n-hexyl)-substituted COEs (3-R-COEs) afforded only the α-GC,ω-vinyl-poly(3-R-COE)s, as a result of the steric hindrance around the active intermediate, while a 5-ethyl substituted COE (5-Et-COE) enabled access to the corresponding α,ω-di(GC)-poly(5-Et-COE). The ROMP of 5,6-epoxy-, 5-hydroxy- and 5-oxo-functionalized COEs in the presence of acryloyl-GC as the CTA has also been achieved, affording from the first two monomers polymers with GC end-groups at both extremities, while a 60 : 40 mixture of mono- and di-GC terminated P(5-O[double bond, length as m-dash]COE) was observed in the latter case