This paper concerns periodic solutions of a class of equations that model gene regulatory networks. Unlike the vast majority of previous studies, it is not assumed that all decay rates are identical. To handle this more general situation, we rely on monotonicity properties of these systems. Under an alternative assumption, it is shown that a classical fixed point theorem for monotone, concave operators can be applied to these systems. The required assumption is expressed in geometrical terms as an alignment condition (...) on so-called focal points . As an application, we show the existence and uniqueness of a stable periodic orbit for negative feedback loop systems in dimension 3 or more, and of a unique stable equilibrium point in dimension 2. This extends a theorem of Snoussi, which showed the existence of these orbits only. (shrink)
Abstract Ecological communities around the world are under threat while a consensus theory of community structure remains elusive. In the last decade ecologists have struggled with two seemingly opposing theories: niche-based theory that explains diversity with species’ differences and the neutral theory of biodiversity that claims that much of the diversity we observe can be explained without explicitly invoking species’ differences. Although ecologists are increasingly attempting to reconcile these two theories, there is still much resistance against the neutral theory of (...) biodiversity. Here we argue that the dispute between the two theories is a classic example of the dichotomy between philosophical perspectives, realism and instrumentalism. Realism is associated with specific, small-scale and detailed explanations, whereas instrumentalism is linked to general, large-scale, but less precise accounts. Recognizing this will help ecologists get both niche-based and neutral theories in perspective as useful tools for understanding biodiversity patterns. Content Type Journal Article Category Regular Article Pages 1-15 DOI 10.1007/s10441-012-9144-6 Authors Paul L. Wennekes, Community and Conservation Ecology Group, University of Groningen, Groningen, The Netherlands James Rosindell, Institute of Integrative and Comparative Biology, University of Leeds, Leeds, UK Rampal S. Etienne, Community and Conservation Ecology Group, University of Groningen, Groningen, The Netherlands Journal Acta Biotheoretica Online ISSN 1572-8358 Print ISSN 0001-5342. (shrink)
The natural based view of the firm using Hart (1995) is applied to firm responses in the Carbon Disclose Project (CDP) database. A large cross sectional sample(n=573) of North American and European firms is divided into 3 categories of proactivity to the climate change issue using 8 indicators of four resource domains. Results are presented along geographic and size dimensions.
The dynamic properties of amorphous polymers were investigated during long-term ageing by means of high resolution low-frequency mechanical spectroscopy. Two polymers are considered in this work, namely atactic polystyrene and quenched amorphous poly(ethylene naphthalate). It is shown that during ageing at temperatures higher than that of secondary relaxation, but lower than that of the primary one (if tested at 1?Hz), the strength of the secondary relaxation first increases and then decreases for long ageing times. This phenomenon is explained on the (...) basis of the concepts of the heterogeneous cohesion of the amorphous network at the nanometric scale and the cooperation of molecular motions responsible for the secondary relaxations. (shrink)
The work exposed hereafter intends to examine the ambiguous character of identities according to the analyses of the French philosopher Étienne Balibar. The text will focus on his works from the late eighties, where there is a distancing from the circle formed around Althusser and an approach to the philosophies of difference of Foucault, Deleuze and Derrida. We will seek to explain how the author, through the prism of Marxist class conflicts, will denounce the echelonment process of individuals in a (...) hierarchical fashion within the capitalist world-economy based on multiple identity processes which respect the logic of maintaining the existing international social structure. The background of such analyses is the rise of xenophobic and neo-fascists movements which have not ceased to increase in today's Europe as a reaction to a profound crisis of the nation-state, its institutions and the fragmentation of ideally established communities. (shrink)
Étienne de La Boétie (1530–63) is a central, if enigmatic, figure in modern French political philosophy. While his name is most famous for his friendship with Montaigne, his Discours de la servitude volontaire (Discourse of Voluntary Servitude) is a tour-de-force of humanist political writing, a youthful paean to liberty arguing that subjection to tyrants is the result of popular corruption. This article argues that the text can be read as a reflection on the perils and promise of transparency. Reading La (...) Boétie helps us see two radically different ways in which members of a polity can be known to one another – two models of transparency – and it offers an important, but ultimately unsettling, political ideal based on a classical conception of civic friendship. The article draws out the importance of this ideal for modern anti-corruption efforts. (shrink)
Etienne-François Geoffroy, l’un des chimistes français les plus importants du début du XVIIIe siècle, entretenait des relations régulières avec l’Angleterre. Il était chargé de développer les échanges entre l’Académie royale des sciences et la Royal Society de Londres. Quand il publia sa « Table des rapports entre les substances chimiques » en 1718, Fontenelle et quelques autres lui reprochèrent d’avoir introduit en chimie le système des attractions newtoniennes. Mais en fait, Geoffroy s’est toujours tenu à l’écart aussi bien du (...) mécanisme cartésien que du newtonianisme, le recours aux expériences et à la littérature alchimique constituant ses seules sources d’inspiration. Geoffroy apparaît ainsi comme le représentant d’une chimie empirique, soucieuse de conserver l’autonomie de sa discipline. (shrink)
« Rythmes et Croyances au Moyen-Âge » Journée d'études organisée par Marie Formarier et Jean-Claude Schmitt 23 juin 2012 – Paris Présentation : Cette journée d'études a eu pour objectif de faire dialoguer les diverses disciplines concernées par le rapport entre rythmes et croyances au Moyen-Âge. Elle a accueilli des historiens, des anthropologues, des sociologues, des philologues et des linguistes. Présents dans la langue latine et les langues vernaculaires, dans la rhétorique du sermon, la prière et (...) - Histoire – (...) NOUVELLE JOURNÉE d'ÉTUDES. (shrink)