Reasonning in naive set theory (with unlimited comprehension), we derive a paradox (a formal contradiction) which can be seen as a variant of the Burali-Forti paradox.

We introduce a notion of syntactical truth predicate (s.t.p.) for the second order arithmetic PA 2 . An s.t.p. is a set T of closed formulas such that: (i) T(t = u) if and only if the closed first order terms t and u are convertible, i.e., have the same value in the standard interpretation (ii) T(A → B) if and only if (T(A) $\Longrightarrow$ T(B)) (iii) T(∀ x A) if and only if (T(A[x ← t]) for any closed first (...) order term t) (iv) T(∀ X A) if and only if (T(A[X ←▵]) for any closed set definition $\triangle = \{x \mid D(x)\}$ ). S.t.p.'s can be seen as a counterpart to Tarski's notion of (model-theoretical) validity and have main model properties. In particular, their existence is equivalent to the existence of an ω-model of PA 2 , this fact being provable in PA 2 with arithmetical comprehension only. (shrink)

Both the physiological and the pathological morphogenetic processes that we can meet in embryogenesis, neogenesis and degenerative dysgenesis present common features: they are ruled by three different kinds of mechanisms, one related to cell migration, the second to cell differentiation and the third to cell proliferation. We deal here with an application to the cambial growth which essentially involves the third type of mechanism.Woody plants produce secondary tissue (secondary xylem and phloem) from a meristematic tissue called vascular cambium, responsible for (...) the radial growth of a tree. This paper focuses on the formation of secondary xylem, considered in two dimensions in a cross-section framework. A new discrete modelling approach is used, based on the cellular scale, in order to attain a more accurate understanding of how the elementary microscopic behaviour of each cell takes part in the macroscopic morphogenesis. The mathematical model essentially uses an occurrence method simulating the main features of radial growth with simple geometric rules, such as Thom's division rule (Thom,1972)to account for the cell proliferation. The study applies to concrete instances in which the changes made in the geometrical cellular patterns of the vascular cambium clearly affect the shape of the tree, as in Pinus radiata (D. Don.). (shrink)

Morphogenesis is a key process in developmental biology. An important issue is the understanding of the generation of shape and cellular organisation in tissues. Despite of their great diversity, morphogenetic processes share common features. This work is an attempt to describe this diversity using the same formalism based on a cellular description. Tissue is seen as a multi-cellular system whose behaviour is the result of all constitutive cells dynamics. Morphogenesis is then considered as a spatiotemporal organization of cells activities. We (...) show how this formalism relies on Reaction–Diffusion/Positional Information approach and how it permits to generalize its modelling possibilities. Three quite different applications for concrete morphogenetic processes are presented. The first one is a model for epithelial invagination, the second is a model of cellular differentiation by local cell–cell signalling. The last example is the secondary radial growth of conifer trees. From the mathematical point of view, different modelling tools are used according to the specificity of each process. (shrink)

L’installation et le développement de la discipline universitaire « Sciences et techniques des activités physiques et sportives » ne peuvent être pleinement compris que si l’on voit qu’ils résultent de l’action conjointe de facteurs cognitifs et sociaux. La perspective sociohistorique montre que ce qui est arrivé récemment a d’abord été préparé par un long processus non linéaire et complexe. Mais il a encore fallu sur le court terme un dynamisme cognitif interne et des effets sociaux multiples, enchevêtrés, voulus et non (...) voulus, afin que s’établissent l’instutionnalisation irréversible de cette nouvelle discipline universitaire, son « académisation », puis son expansion « démographique ».The setting-up and development of the « sport sciences » as an academic discipline can only be fully grasped by acknowledging that it results from the combined action of both cognitive and social factors. Viewed in a social and historical light, what has recently taken place proves to have come at the end of a long, complex and winding process. But, in the short run, internal cognitive dynamics as well as multiple and intertwined social effects – whether intended or not – were also necessary for the non-reversible institutionalization of this new academic discipline, its establishment as part of the academia and eventually its « demographic » expansion. (shrink)

Cet article a pour objet la conception de matériel pédagogique pour l’apprentissage endolingue de la relation entre le passé composé et l’imparfait dans le récit en FLE. Faut-il privilégier le choix d’une visée sur le procès ou bien montrer que la distribution des temps s’effectue à partir d’indices contextuels qu’il faut repérer? La première position a été représentée, par exemple, dans le manuel Libre Échange, mais délaissée par la suite. Notre propre analyse de 17 manuels publiés entre 2006 et 2016 (...) confirme la tendance. On constate en outre qu’il n’y a aucun exemple d’un même procès sous les deux aspects accompli et inaccompli, comme si cette option avait été bannie. Toutefois, l’approche aspectuelle n’est pas tout-à-fait absente : on considère le cas d’un manuel tendant à intégrer présence d’un sujet opérant des choix de visée et emplois normés des temps. Finalement, on propose un matériel qui exploite la syntaxe distincte des énoncés avec l’imparfait et le passé composé. Dans un cadre énactif, on envisage que l’énonciateur prend deux états différents, où il perçoit un présent imaginé, ou bien où il devient « possesseur » d’un accompli. On détaille la conception théorique, décrit des visuels extraits du matériel, et suggère une gestuelle pédagogique pour montrer comment cette approche peut soutenir l’apprentissage des temps du récit. (shrink)

We propose that interaction rules derived from polyamine exchange in connected cells may explain the spatio‐temporal organization of gap junctions observed during tissue regeneration and tumorigenesis. We also hypothesize that polyamine exchange can be considered as signal that allows cells to sense the proliferation status of their neighbors. Polyamines (putrescine, spermidine, and spermine) are indeed small aliphatic polycations that serve as fuels to sustain elevated proliferation rates of the order observed in cancer cells. Based on recent reports, we consider here (...) that polyamines can be exchanged through gap junction channels between mammalian cells. Such intercellular exchange of polyamines has critical consequences on the local control of growth. In line with this hypothesis, the complex protein network that keeps polyamine levels finely tuned in mammalian cells can translate polyamine efflux or influx into integrated signals controlling transcription, translation, and cell communications. (shrink)

Résumé Cet article présente l’analyse d’une expérience de construction de savoirs mathématiques en rapports avec les machines, dans les années 1950 et 1960, à une époque où le calcul analogique cohabitait avec le calcul digital (c’est-à-dire le futur « ordinateur », terme introduit dans la langue française pour désigner principalement les « digital computers »). Les mathématiques en jeu relèvent des théories des systèmes dynamiques, c’est-à-dire des outils mathématiques construits pour comprendre la dynamique de différents types de systèmes, qu’ils soient (...) mathématiques, physiques, biologiques, mécaniques, etc. L’objet du présent article est à la fois un groupe de chercheurs, leurs pratiques de « mathématiques pour l’ingénieur », leurs efforts pour construire des calculateurs analogiques (mécanique ou électronique) pour étudier la dynamique, le programme baptisé « Dynamique théorique » qu’ils se sont fixés, et l’épistémologie des mathématiques sous-tendant leur pratique. (shrink)

À partir de textes officiels, de publications professionnelles et de représentations d’enseignantes d’EPS ayant vécu la mise en place de la mixité, cet article analyse la construction du genre en éducation physique durant les années 68. Si la mixité est d’abord évacuée au profit de l’officialisation sportive de l’éducation physique, les dissidences acquièrent une légitimité certaine durant la crise de mai-juin 68. Pourtant, l’organisation de l’EPS conserve une frontière et maintient les distinctions sexuées. Au terme des années 68, la mixité (...) n’est plus ignorée et les discriminations se sont déplacées. Elles sont paradoxalement le fruit des enseignantes elles-mêmes qui déconsidèrent la féminité au regard de leurs attentes sportives. (shrink)

The Court of Justice of the European Union (CJEU) has some basic structural features similar to that of most judicial bodies. According to the treaties, the members of the Court are chosen from individuals whose independence is beyond doubt and who possess the ability required for appointment to higher judicial offices. The involvement of the Court and its president in the most important reforms of the European Union's judicial architecture in recent years is a striking feature which may be called (...) judicial self‐government. International courts have shifted away from being principally committed to dispute settlement towards pursuing other goals, such as advancing international norms and facilitating cooperative international arrangements. The reinforcement of the cooperation of the Court with national courts on the one hand, and with international courts and tribunals on the other, is one of the great current challenges facing the Court. (shrink)

Cet échange avec l’association grenobloise À bientôt j’espère retrace un travail singulier de diffusion itinérante de films documentaires qui expérimente depuis plusieurs années des possibilités alternatives de visionnage cinématographique. Comment organiser des milieux conviviaux de rencontre entre publics hétérogènes, non spécialisés et formes cinématographiques méconnues?

We have developed an approach to implementing a system for managing situated knowledge for complex instruments. Our aim is to develop a system that guides a user through the steps for operating complex scientific instruments. A user manual is often inadequate support for a community of users, so direct communication with an expert is often required. One reason for this is that not all of the author’s expert knowledge was included in the manual, thus limiting the contents to explicit knowledge. (...) This is a main concern of modern knowledge management practitioners who are attempting to design systems that consider both explicit and tacit knowledge. The key is to distribute explicit knowledge through interaction with the real world so that users can develop tacit knowledge as well as acquire explicit knowledge. We describe technical difficulties related to referencing the real world, which is required for interaction, and describe a novel approach to building a low-cost three-dimensional pointer for obtaining the required knowledge, which constitutes our preliminary result. (shrink)

The agronomist who wants to study the nutrient and water uptake of roots needs a quantitative three-dimensional dynamic model of the structure of root systems.The model presented takes into account current knowledge about the morphogenesis of root systems. It describes the root system as a set of root axes, characterised by their orders. The morphogenetic properties of root axes differ according to their order. The axes of order 1 are directly inserted on the stem, the axes of order 2 are (...) inserted on axes of order 1, and so on. They tend to be more plagiotropec and to have less vascular bundles as the order increases. (shrink)

Résumé Loin d’être un programme de recherche tourné uniquement vers l’abstraction, la physiocratie comporte une dimension empirique tout à fait centrale dans sa constitution et dans son développement. L’étude de cette dimension permet de mettre au jour les liens généalogiques et méthodologiques qui ont uni le mouvement physiocratique et les traditions anglaise et française de l’arithmétique politique. En outre, une attention portée à l’inventaire des différentes activités agricoles et à la mesure de leurs productions respectives témoigne d’une autre influence importante (...) dans la construction de l’économie politique de Quesnay, à savoir l’agronomie, alors en plein renouveau sous l’impulsion de Duhamel du Monceau. (shrink)

Most decisions concerning insurance and self-protection have to be taken in situations in which the effort exerted precedes the moment uncertainty realizes, and the probabilities of future states of the world are not perfectly known. By integrating these two characteristics in a simple theoretical framework, this paper derives plausible conditions under which ambiguity aversion raises the demand for insurance and self-protection. In particular, it is shown that in most usual situations where the level of ambiguity does not increase with the (...) level of effort, a simple condition of ambiguity prudence known as decreasing absolute ambiguity aversion is sufficient to give a clear and positive answer to the question: Does ambiguity aversion raise the optimal level of effort? (shrink)

This paper reflects on the notion of partial ambiguity. Using a framework decomposing ambiguity into distinct layers of analysis, among which are risk and model uncertainty, and allowing for different attitudes toward these layers, I show that partial ambiguity may prove less desirable than full ambiguity, even under ambiguity aversion. This observation poses difficulties for interpreting the notion of partial ambiguity in relation to the partial information available to determine the potential compositions of an ambiguous urn. Two Ellsberg-style thought experiments (...) are described to challenge the meaning of partial ambiguity further, and an alternative interpretation, based on a more ambiguous relation, is discussed. (shrink)

Implemented gradually since 2002 and following in the footsteps of the “Bologna Process” initiated in the late 1990s, successive reforms of university education in France have profoundly changed the landscape of higher professional degrees. The Diplômes d’Enseignement Supérieur Spécialisé (DESS) (Specialized Higher Education Diplomas), which have become professional Masters, offer a paradigmatic example of the tensions between the former aims of professionalization in universities and the teaching to, by, or for research present in these diplomas. The case of the professional (...) Master’s degree in “Strategy and Engineering in Adult Training” (SIFA) at Rennes 2 University illustrates this problem. (shrink)

This article poses the question of the social and intellectual conditions for genuine social scientific internationalism, through an analysis of the worldwide spread of a new global vulgate resulting from the false and uncontrolled universalization of the folk concepts and preoccupations of American society and academe. The terms, themes and tropes of this new planetary doxa - `multiculturalism', `globalization', `liberals versus communitarians', `underclass', racial `minority' and identity, etc. - tend to project and impose on all societies American concerns and viewpoints, (...) thereby transfigured into tools of analysis and yardsticks of policy fit to naturalize the peculiar historical experience of one peculiar society, tacitly instituted as a model for humanity. The article suggests how the logic of the international circulation of ideas, the transformations of the academic field, the strategies of foundations and publishers, and of local collaborators in global conceptual `import-export' converge to foster a particularly powerful and pernicious form of cultural imperialism of which academics are at once perpetrators and victims. (shrink)

I use the collection of “carnal ethnographies” of martial arts and combat sports assembled by Raul Sanchez and Dale Spencer under the title Fighting Scholars to spotlight the fruitfulness of deploying habitus as both empirical object (explanandum) and method of inquiry (modus cognitionis). The incarnate study of incarnation supports five propositions that clear up tenacious misconceptions about habitus and bolster Bourdieu’s dispositional theory of action: (1) far from being a “black box,” habitus is fully amenable to empirical inquiry; (2) the (...) distinction between primary (generic) and secondary (specific) habitus enables us to capture the malleability of dispositions; (3) habitus is composed of cognitive, conative and affective elements: categories, skills, and desires; (4) habitus allows us to turn carnality from problem to resource for the production of sociological knowledge; and (5) thus to realize that all social agents are, like martial artists, suffering beings collectively engaged in embodied activities staged inside circles of shared commitments. (shrink)

In this response to my critics, I amplify the conceptual clarification and methodological stipulation of habitus begun in ‘Homines in extremis’ to help us move from a sociology of the body as socially construc-ted object to a sociology from the body as socially construc-ting vector of knowledge, power, and practice. The specification of habitus by membership in collectives, attachment to institutions, and analytic purpose makes it a flexible multi-scalar notion with which to construct the epistemic individual and account for both (...) reproduction and change, conformity and creativity, as well as self-revision. For this, we must reject theological interpretations that rigidly lock habitus into Bourdieu’s framework; avoid conflating the formal properties of the notion with its concrete features in specific settings and cases; and distinguish between the rhetorical invocation of his concepts (‘speaking Bourdieuese’) and their effective deployment in the construction of the empirical object. As embodied and embedded capacity, habitus brings temporality, depth, and desire to the analytic epicenter. It reminds us that the social world is not transparent, open-ended, and instantaneous, but endowed with gravity, opacity, and asymmetry. Treating the sentient and skilled organism as fount of both social intelligence and sociological acumen can help historical social science connect with enactive psychology and recover the carnality of action that conventional accounts of social life routinely erase. (shrink)

À rebours de la thèse sur la modernité comme une époque où la rationalisation aurait pris le dessus sur la dimension esthétique et affective, Reckwitz repère les différentes étapes de la construction d’un capitalisme esthétique, où l’inventivité revêt désormais un rôle crucial. Tandis que la créativité était brandie par les avant-gardes artistiques du xix e et du xx e siècle comme un idéal permettant de subvertir les normes sociales, la créativité représente aujourd’hui elle-même une norme incontournable. « Soyez créatifs » (...) : cette injonction paradoxale s’applique désormais à tous les sujets du capitalisme tardif. Extrait de sa grande étude sur L’Invention de la créativité, ce chapitre replace l’enjeu de l’esthétisation au cœur de ce que Reckwitz nomme le « dispositif de la créativité ». (shrink)

Written in the form of a dialogue with Brussels sociologist Dieter Vandebroeck, this article retraces the social and intellectual trajectory of Loïc Wacquant as stepping stone to reviewing and discussing the major concepts coined and theoretical propositions elaborated in the course of his research on comparative urban marginality, racial domination, the ghetto, the penal state, neoliberalism, and carnality. This provides an opportunity to specify the relationships between ethnography, history and theory; the dialectic of domination and resistance; the role of (...) public (dis)honor in social life; the uses of Bourdieu's bureaucratic field; and the social and academic conditions of incubation, diffusion, and death of scholarly myths such as the “underclass.” The article closes on a call to clearly distinguish the rhetorical, metaphorical, and analytical usages of concepts and reaffirms the need for epistemic reflexivity as sine qua non for the articulation of robust scientific problematics. (shrink)

The comparative sociology of the structure, dynamics, and experience of urban relegation in the United States and the European Union during the past three decades reveals the emergence of a new regime of marginality. This regime generates forms of poverty that are neither residual, nor cyclical or transitional, but inscribed in the future of contemporary societies insofar as they are fed by the ongoing fragmentation of the wage labour relationship, the functional disconnection of dispossessed neighbourhoods from the national and global (...) economies, and the reconfiguration of the welfare state in the polarizing city. Based on a methodical comparison between the black American ghetto and the French working-class banlieue at century's turn, this article spotlights three distinctive spatial properties of `advanced marginality' — territorial fixation and stigmatization, spatial alienation and the dissolution of `place', and the loss of a hinterland — and draws out their implications for the formation of the `precariat' in postindustrial societies. (shrink)

The comparative sociology of the structure, dynamics, and experience of urban relegation in the United States and the European Union during the past three decades reveals the emergence of a new regime of marginality. This regime generates forms of poverty that are neither residual, nor cyclical or transitional, but inscribed in the future of contemporary societies insofar as they are produced by the ongoing fragmentation of wage labor relation­ship, the functional disconnection of dispossessed neighborhoods from the national and global economies, (...) and the reconfiguration of the welfare state in the polarizing city. Based on a methodical comparison of the black American ghetto and the French working-class banlieue at century’s turn, this article spotlights three distinctive spatial properties of “advanced marginality”—territorial fixation and stigmatization, spatial alienation and the dissolution of “place,” and the loss of a hinterland—and draws out their implications for the formation of the “precariat” in postindustrial societies. (shrink)