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Search Results: 1 - 10 of 13235 matches for " Eric Dugas "
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Comparing Climate Change Coverage in Canadian English and French-Language Print Media: Environmental Values, Media Cultures, and the Narration of Global Warming
Nathan Young,Eric Dugas
The Canadian Journal of Sociology , 2012,
Abstract: This article compares how climate change is presented in English- andFrench-language print media in Canada. In recent years, climate change has become an increasingly divisive issue, with the media playing a central role in the promotion of competing claims and narratives in the public sphere. Using concepts from environmental sociology and the sociology of journalism, we examine content from six English- and two French-language newspapers from 2007–2008 (N=2,249), and find significant evidence of both convergence and divergence across the language divide. Among the most significant findings are differences in how complexity is handled: English outlets present diverse coveragethat is highly compartmentalized, while the French newspapers present a narrower range of coverage but with thematically richer articles that better link climate change issues to the realms of culture, politics, and economy.
Du sport aux activités physiques de loisir : des formes culturelles et sociales bigarrées
éric Dugas
SociologieS , 2007,
Abstract: L'espace ludique des formes sociales des pratiques physiques accepte maintes variations. Du jeu informel et libre aux activités physiques institutionnelles (les sports), plusieurs catégories de situations motrices, distinctes des unes des autres, jalonnent l'espace des jeux sportifs. Après avoir défini et délimité, dans un premier temps, les contours et la richesse de l'univers des pratiques physiques ludiques, nous essayons, dans un second temps de mettre au jour le type de pratiques qui co ncident le mieux aux aspirations des pratiquants du xxie siècle. On s'aper oit actuellement que malgré l'hégémonie du sport au sein de l'espace médiatique et économique, il se dessine néanmoins une tendance forte : la prédominance d’activités physiques ludiques de plus en plus autocontr lées qui laissent l'initiative aux pratiquants et dans lesquelles les institutions sportives ne sont plus totalement ou pas du tout ma tre du jeu. From sport to leisure physical activities: mixed cultural and social formsThe game space of physical activities' social forms accepts many variations. From informal and free games to institutional physical activities (sports), several motor situation categories, distinct from each other, punctuate the space of physical games. After having specified and delimited the contours and richness of the world of playful physical activities, we will try to bring to light the kind of practices which coincide best with the 21st century's players or sports (wo)men. Currently, we can see that in spite of sport's hegemony within the media and the economic spheres, a strong tendency is becoming apparent: the predominance of more and more self-controlled playful physical activities, which leave the initiative to players and in which governing bodies are not totally or not at all in command any more. Del deporte a las actividades de ocio: una mezcolanza en las formas culturales y socialesEl espacio lúdico de las formas sociales de las prácticas físicas acepta amplias variaciones. Del juego informal y libre a los juegos deportivos institucionalizados (deportes), varias son las categorías de situaciones motrices, distintas las unas de las otras, que ocupan el espacio de los juegos deportivos. Intentamos, en un primer paso, definir y delimitar las fronteras y la riqueza del universo de las prácticas físicas lúdicas; para en un segundo tiempo, presentar el tipo de prácticas que mejor se adaptan a las aspiraciones de los practicantes del siglo XXI. En la actualidad percibimos, a pesar de la hegemonía del deporte en el seno del espacio mediático y económico, la c
Torsion-free Abelian groups defined by an integral matrix
M. Dugas
International Journal of Algebra , 2012,
Chronologie du Yémen 2003
Marc Dugas
Chroniques Yéménites , 2003,
Abstract: CEFAS, Marc Dugas prépare, à l'université Paris IV - Sorbonne, sous la direction de Franck Lestringant, un DEA sur les voyageurs européens en Arabie. Mon enquête s'appuie essentiellement sur tout ce qui est accessible en langue anglaise sur le Yémen : presse yéménite, saoudienne ou autre, dépêches de presse de l'agence Sabanews ou d'autres agences internationales, rapports d'ONG, etc. Si j'ai confronté ces sources aux dépouillements de la presse yéménite que l'ambassade de France à San...
Periodicity of d-cluster-tilted algebras
Alex Dugas
Mathematics , 2010,
Abstract: It is well-known that any maximal Cohen-Macaulay module over a hypersurface has a periodic free resolution of period 2. Auslander, Reiten and Buchweitz have used this periodicity to explain the existence of periodic projective resolutions over certain finite-dimensional algebras which arise as stable endomorphism rings of Cohen-Macaulay modules. These algebras are in fact periodic, meaning that they have periodic projective resolutions as bimodules and thus periodic Hochschild cohomology as well. The goal of this article is to generalize this construction of periodic algebras to the context of Iyama's higher AR-theory. We start by considering projective resolutions of functors on a maximal (d-1)-orthogonal subcategory C of an exact Frobenius category B. If C is fixed by the d-th syzygy functor of B, then we show that this d-th syzygy functor induces the (2+d)-th syzygy on the category of finitely presented functors on the stable category of C. If C has finite type, i.e., if C = add(T) for a d-cluster tilting object T, then we show that the stable endomorphism ring of T has a quasi-periodic resolution over its enveloping algebra. Moreover, this resolution will be periodic if some higher syzygy functor is isomorphic to the identity on the stable category of C. It follows, in particular, that 2-C.Y. tilted algebras arising as stable endomorphism rings of Cohen-Macaulay modules over curve singularities, as in the work of Burban, Iyama, Keller and Reiten have periodic bimodule resolutions of period 4.
Tilting mutation of weakly symmetric algebras and stable equivalence
Alex Dugas
Mathematics , 2011, DOI: 10.1007/s10468-013-9422-2
Abstract: We consider tilting mutations of a weakly symmetric algebra at a subset of simple modules, as recently introduced by T. Aihara. These mutations are defined as the endomorphism rings of certain tilting complexes of length 1. Starting from a weakly symmetric algebra A, presented by a quiver with relations, we give a detailed description of the quiver and relations of the algebra obtained by mutating at a single loopless vertex of the quiver of A. In this form the mutation procedure appears similar to, although significantly more complicated than, the mutation procedure of Derksen, Weyman and Zelevinsky for quivers with potentials. By definition, weakly symmetric algebras connected by a sequence of tilting mutations are derived equivalent, and hence stably equivalent. The second aim of this article is to study these stable equivalences via a result of Okuyama describing the images of the simple modules. As an application we answer a question of Asashiba on the derived Picard groups of a class of self-injective algebras of finite representation type. We conclude by introducing a mutation procedure for maximal systems of orthogonal bricks in a triangulated category, which is motivated by the effect that a tilting mutation has on the set of simple modules in the stable category.
Torsion pairs and simple-minded systems in triangulated categories
Alex Dugas
Mathematics , 2012, DOI: 10.1007/s10485-014-9365-8
Abstract: Let T be a Hom-finite triangulated Krull-Schmidt category over a field k. Inspired by a definition of Koenig and Liu, we say that a family S of pairwise orthogonal objects in T with trivial endomorphism rings is a simple-minded system if its closure under extensions is all of T. We construct torsion pairs in T associated to any subset X of a simple-minded system S, and use these to define left and right mutations of S relative to X. When T has a Serre functor \nu, and S and X are invariant under \nu[1], we show that these mutations are again simple-minded systems. We are particularly interested in the case where T is the stable module category of a self-injective algebra \Lambda. In this case, our mutation procedure parallels that introduced by Koenig and Yang for simple-minded collections in the derived category of \Lambda. It follows that the mutation of the set of simple \Lambda-modules relative to X yields the images of the simple \Gamma-modules under a stable equivalence between \Gamma\ and \Lambda, where \Gamma\ is the tilting mutation of \Lambda\ relative to X.
Periodic resolutions and self-injective algebras of finite type
Alex Dugas
Mathematics , 2008,
Abstract: We say that an algebra A is periodic if it has a periodic projective resolution as an (A,A)-bimodule. We show that any self-injective algebra of finite representation type is periodic. To prove this, we first apply the theory of smash products to show that for a finite Galois covering B --> A, B is periodic if and only if A is. In addition, when A has finite representation type, we build upon results of Buchweitz to show that periodicity passes between A and its stable Auslander algebra. Finally, we use Asashiba's classification of the derived equivalence classes of self-injective algebras of finite type to compute bounds for the periods of these algebras, and give an application to stable Calabi-Yau dimensions.
Auto-equivalences of stable module categories
Alex Dugas
Mathematics , 2014,
Abstract: We construct nontrivial auto-equivalences of stable module categories for elementary, local symmetric algebras over a field k. These auto-equivalences are modeled after the spherical twists of Seidel and Thomas and the $\mathbb{P}^n$-twists of Huybrechts and Thomas, which yield auto-equivalences of the derived category of coherent sheaves on a variety. For group algebras of p-groups in characteristic p we recover many of the auto-equivalences corresponding to endo-trivial modules. We also obtain analogous auto-equivalences for local algebras of dihedral and semi-dihedral type, which are not group algebras.
Resolutions of mesh algebras: periodicity and Calabi-Yau dimensions
Alex Dugas
Mathematics , 2010, DOI: 10.1007/s00209-011-0908-5
Abstract: A triangulated category is said to be Calabi-Yau of dimension d if the dth power of its suspension is a Serre functor. We determine which stable categories of self-injective algebras A of finite representation type are Calabi-Yau and compute their Calabi-Yau dimensions. We achieve this by studying the minimal projective resolution of the stable Auslander algebra of A over its enveloping algebra, and use covering theory to reduce to (generalized) preprojective algebras of Dynkin graphs. We also describe how this problem can be approached by realizing the stable categories in question as orbit categories of the bounded derived categories of hereditary algebras.
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