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Quantum theory does not need complex numbers
No full textThe longstanding debate over whether quantum theory fundamentally requires complex numbers-or if their use is merely a convenient choice-has persisted for decades. Until recently, this question was considered open. However, in [M.-O. Renou et al, Nature 600, 625-629, 2021], a decisive argument was presented asserting that quantum theory needs complex numbers. In this work, we demonstrate that a formulation of quantum theory based solely on real numbers is indeed possible while retaining key features such as theory-representation locality (i.e. local physical operations are represented by local changes to the states) and the positive semi-definiteness of its states and effects. We observe that the standard system combination rule-the tensor product-was derived after the development of single-system complex quantum theory. By starting from a single-system quantum theory using only real numbers, we derive a combination rule that produces a real quantum theory with properties analogous to those of conventional complex quantum theory. We also prove that the conventional tensor product rule can also lead to a real and representation-local theory, albeit with a modified characterization of the state space. We thus conclude that complex numbers are a mere convenience in quantum theory. CONTENTS 1. Positivity-preserving mapping on a single system 2. Positivity-preserving mapping on two subsystems C. Explicit constructions of the M (•) map D. Proof of Theorem 2
Corps à lire, textes à vendre : l'atelier d'artiste dans la fiction (1867-1919), entre voyeurisme et prostitution
No full textInternational audienceIn the last third of the 19th century, the French-language “roman de l’artiste” seems to have undergone a sexual redefinition. From 1867 onwards, as Manette Salomon shows, the Romantic focus on the artist’s struggle to create the ideal masterpiece shifted to the representation of the materiality of his desire. Through the prism of Naturalism, “l’atelier d’artiste” became a commonplace for illustrating the sex life of the Man of Genius, of which models were a part. As objects of voyeurism, they crystallize both his, and the readers’ quasi-medical obsession with the female body. The prostitution circuit in which most of the women—and even some men—posing for the “artist-client” were involved reflected a reality, and allegorized the ever-growing publishing market. Despite the objectifying message they convey, these representations in turn allowed models, and sex-workers to put in writing their own experience of studio work, as Neel Doff’s autobiographical novel Keetje (1919) testifies. (In French)
Spatial Distribution of European Grayling Reflects Longitudinal Temperature Patterns in a Swiss River
No full textInternational audienceMost salmonid populations are declining across their entire habitat range, partly because of large‐scale loss of crucial physical habitats. Alterations in river flow and temperature resulting from climate change are likely to further degrade habitat quality, particularly summer thermal conditions experienced by temperature‐sensitive fish species. Understanding how summer thermal conditions control the spatial distribution of ectotherms is thus central to helping project the consequences of climate change and develop management solutions. This study uses snorkelling fish surveys collected over 10 years and airborne thermal infrared (TIR) mapping of surface temperature acquired in 2022 to assess the relationship between European grayling distribution and thermal habitats along a 9‐km long reach of the Allondon River, Switzerland. Results show that all 3 grayling life stages (adults, sub‐adults and juveniles) respond negatively to elevated summer temperature, with distribution patterns highlighting thermal structuring effects on fish populations. The presence of two cooler reaches appears critical to the survival of the Allondon's declining grayling population, while the warmest reach that separates these habitats potentially acts as a thermal barrier during critical summer conditions. These results were used to guide local stakeholders towards short‐term and longer‐term actions to be taken on the river, which include: concerted trans‐national management to protect key upstream tributaries, tree planting to limit summer peak temperature and strategic protection of cold‐water patches that may act as thermal refuges during critical periods
« L’“étrange magnanimité” des artistes qui font don de leurs œuvres : l’exemple de Botticelli et de Lorenzo Costa »
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Evaluation of global biotic resource consumption against absolute boundaries
No full textInternational audienceHuman activities rely on biotic natural resources to provide products and services necessary to meet human needs. This instrumental value is captured in life-cycle assessment through the “Natural resources” Area of Protection. Although several absolute boundaries have been proposed to safeguard biotic resources, it remains unclear whether these resources are currently used at a sustainable rate. This study addresses this question by evaluating global biotic resource consumption from 1995 to 2011 against suggested biotic resource boundaries, relying on Exiobase projections to assess the evolution beyond 2011. The assessment couples absolute boundaries with life-cycle impact assessment (LCIA) methods, enabling evaluation using consistent LCIA metrics. Five absolute boundaries and four LCIA methods were adapted to the Exiobase multiregional input-output model. Results show that most of existing boundaries are already transgressed, regardless of whether mass-based or LCIA-based control variables are applied. The wide range and normative nature of existing boundaries emphasize the need for harmonized, science-based boundaries to ensure the sustainable use of biotic resources
[Introduction à la partie " Les économistes" ] L'économie politique à la faculté de droit de Lyon : une diversité théorique et doctrinale
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Les effets de la brièveté dans les entrées encyclopédiques
No full textInternational audienceLe volume textuel prodigieux des dictionnaires et encyclopédies impose des contraintes, notamment techniques et financières, aux comités éditoriaux à l'origine de tels projets. Au niveau lexical, le recours aux abréviations et aux contractions permet d'assurer la concision des entrées. Cet article étudie leur emploi dans deux encyclopédies de langue française: l'Encyclopédie, Dictionnaire raisonné des sciences, des arts et des métiers, par une Société de Gens de lettres ainsi que La Grande Encyclopédie, Inventaire Raisonné des Sciences, des Lettres et des Arts par une Société de savants et de gens de lettres. Il montre que les abréviations sont présentes dans de nombreux aspects propres aux encyclopédies tels que l'organisation en domaines de connaissances ou la mise en relation d'entrées au moyen de renvois. Enfin, il s'intéresse à ces formes abrégées du point de vue des outils de traitement automatiques utilisés en linguistique de corpus
Sortir de la médecine générale libérale : les effets croisés de la socialisation professionnelle, de classe et de genre
No full textInternational audience"While entry into the profession of general practitioner and the way it is practiced have been the subject of numerous sociological studies, the forms of exit from the profession have scarcely been explored. This article sheds light on them through an analysis of professional socialization and its variations. Our interview-based study, conducted in working-class rural and peri-urban areas, with 65 general practitioners who left private practice or adapted it, reveals the gendered costs of non-conformity to a professional model of availability that corresponded to a previous (male) state of the profession. We show that exiting or adapting private practice responds to dispositional crises revealing physicians’ misalignment with the professional model of permanent availability, a phenomenon that is determined by primary, class, and gender socialization. Lastly, we show how the decline in public services favors exiting private practice."Si l’entrée dans la profession de médecin généraliste et ses modalités d’exercice ont fait l’objet d’enquêtes sociologiques nombreuses, les formes de sortie du métier sont peu explorées. Cet article les éclaire par l’analyse de la socialisation professionnelle et de ses inflexions. Notre enquête par entretiens, dans des territoires ruraux et péri-urbains populaires, avec 65 médecins généralistes ayant quitté ou aménagé l’exercice libéral révèle les coûts genrés de la non-conformité à un modèle professionnel de disponibilité ajusté à un état antérieur (masculin) de la profession. Nous montrons que les sorties ou l’aménagement de l’exercice libéral répondent à des crises dispositionnelles révélant le désajustement des médecins au modèle professionnel de la disponibilité permanente, et qu’elles sont déterminées par la socialisation primaire, de classe et de genre. Enfin, nous montrons comment le recul des services publics favorise les sorties de la médecine générale libérale
