The dynamics of the "Etang de Berre", a brackish lagoon situated close to the French Mediterranean sea coast, is strongly disturbed by freshwater inputs coming from an hydroelectric power station. The system dynamics has been described as a sequence of daily typical states from a set of physicochemical variables such as temperature, salinity and dissolved oxygen rates collected over three years by an automatic sampling station. Each daily pattern summarizes the evolution, hour by hour of the physicochemical variables. This article (...) presents results of forecasts of the states of the system subjected to the simultaneous effects of meteorological conditions and freshwater releases. We recall the main step of the classification tree method used to build up the predictive model (Classification and Regression Trees, Breiman et al., 1984) and we propose a transfer procedure in order to test the stability of the model. Results obtained on the Etang de Berre data set allow us to describe and predict the effects of the environmental variables on the system dynamics with a margin of error. The transfer procedure applied after the tree building process gives a maximum gain in prediction accuracy of about 15%. (shrink)
Spatial and temporal heterogeneity are often described as important factors having a strong impact on biodiversity. The effect of heterogeneity is in most cases analyzed by the response of biotic interactions such as competition of predation. It may also modify intrinsic population properties such as growth rate. Most of the studies are theoretic since it is often difficult to manipulate spatial heterogeneity in practice. Despite the large number of studies dealing with this topics, it is still difficult to understand how (...) the heterogeneity affects populations dynamics. On the basis of a very simple model, this paper aims to explicitly provide a simple mechanism which can explain why spatial heterogeneity may be a favorable factor for production. We consider a two patch model and a logistic growth is assumed on each patch. A general condition on the migration rates and the local subpopulation growth rates is provided under which the total carrying capacity is higher than the sum of the local carrying capacities, which is not intuitive. As we illustrate, this result is robust under stochastic perturbations. (shrink)
Systematic sampling of communities gives rise to large contingency tables summing up possible changes in the assemblages' structure. Such tables are generally analysed by multivariate statistical methods, which are ill-suited for simultaneously analysing rare and common species (Field et al., 1982). In order to separately process species belonging to either of these categories, we propose a statistical method to select common species in a sequence of ecological surveys. It is based on a precise definition of rarity, and depends on a (...) rarity parameter. In this work, this parameter will be optimised so that the sub-table of common species captures the essential features of the complete table as well as possible. In this way we analysed the spatio-temporal evolution of macrobenthic communities from the Algiers harbour to study the pollution influence during a year. The examination of the communities' structuring was done through Principal Components Analysis (PCA) of the species proportions table. Environmental variables were simultaneously sampled. We show that the data structure can be explained by about 25% of the total number of present species. Two environmental gradients were brought to the fore inside the harbour, the first one representing pollution, and the second one representing hydrological instabilities. (shrink)
Research in modern biology has largely been developed according to two main ways of inquiry, as they were outlined by Charles Darwin and Claude Bernard. Each stands for a specific approach to the living corresponding to two different methodological rules: the principle of natural selection and the principle of causation.
In this article I confront Jürgen Habermas' deliberative model of democracy with Claude Lefort's analysis of democracy as a regime in which the locus of power remains an empty place. This confrontation reveals several structural similarities between the two authors and explains how the proceduralization of popular sovereignty provides a discourse-theoretical interpretation of the empty place of power. At the same time, Lefort's insistence on the open-ended nature of the democratic struggle also points towards an unresolved tension at the (...) core of Habermas' model between the cognitive nature of deliberation on the one hand and the freedom of moral and political agents on the other. A proper solution of this tension requires a full appreciation of the ineliminable gap between actual and ideal deliberation. Because actual deliberation can never result in an ideal consensus, the actual exercise of democratic power should be understood as an unavoidable interruption of deliberation. Key Words: consensus • deliberation • democracy • empty place of power • Jürgen Habermas • Claude Lefort. (shrink)
Claude Bernard, the father of scientific physiology, believed that if medicine was to become truly scientiifc, it would have to be based on rigorous and controlled animal experiments. Bernard instituted a paradigm which has shaped physiological practice for most of the twentieth century. ln this paper we examine how Bernards commitment to hypothetico-deductivism and determinism led to (a) his rejection of the theory of evolution; (b) his minima/ization of the role of clinical medicine and epidemiological studies; and (c) his (...) conclusion that experiments on nonhuman animals were, "entirely conclusive for the toxicology and hygiene of man". We examine some negative consequences of Bernardianism for twentieth century medicine, and argue that physio/ogy's continued adherence to Bernardianism has caused it to diverge from the other biological sciences which have become increasingly infused with evolutionary theory. (shrink)
: Convinced that logic has a history and that its history always manages to surprise the philosophers, Claude Imbert has devoted much of her work to the study of the Stoic school and of the late-nineteenth-century German logician Gottlob Frege. In the fifth chapter of her book Pour une histoire de la logique, she examines the trajectory of Frege's awareness of what his new logic entails, in particular the way it subverts the project of Kant.
The article deals with the question of persuasion by comparing two passages taken from a text written by Victor Hugo entitled Claude Gueux The first passage is taken from the first part of the text in which Hugo tells the story of the murder of the director of the Clairvaux prison workshop perpetrated by a prisoner, Claude Gueux, followed by the latter’s trial and execution. The second passage studied is taken from the second part of the text in (...) which Hugo argues against the death penalty. This article begins with an intuitive sense that the styles of these passages are “different”: the second one clearly shows Hugo’s persuasive intention, which is to say his effort to make his position be accepted. That said, does this extract have semantic properties that the descriptive passage does not have? The hypothesis advanced is that the organization of contents is of a similar nature in both passages of Claude Gueux and that it is only in an enunciative way that the passages are distinguishable. This enunciative difference allows the militant passage’s locutor to portray himself in a favorable light and, herewith, to convince the reader to his point of view. It is, hence, but in an indirect manner that Hugo’s persuasive intention appears; as it is without a semantic mark. (shrink)
Claude Bernard's concept of the internal environment ( milieu intérieur ) played a crucial role in the development of experimental physiology and the specific medical therapeutics derived from it. This concept allowed the experimentalist to approach the organism as fully determined yet relatively autonomous with respect to its external environment. However, Bernard's theory of knowledge required that he find organismic functioning as the result of an external necessity. He is therefore unable to explain adequately the origin or operation of (...) organismic autonomy. A more complete conception of biological autonomy must include a theory of knowledge that can accommodate the organism as a source of discrimination and determination. Only in this way will it be possible to see organisms as active as well as reactive, as ordering as well as ordered. This shift in perspective is crucial if medicine is to be able to characterize, for example, susceptibility to disease. A cognitive sense of the organic interior is proposed as an alternative to Bernard's internal environment. Keywords: biological autonomy, Claude Bernard, epistemology, internal environment ( milieu intérieur ) CiteULike Connotea Del.icio.us What's this? (shrink)
This study is devoted to the problem of the place and significance of the scientific quest and worldview, and to their articulation with metaphysics as they serve to bring the mind to the consideration of the problem and mystery of the existence of God in the thought of the contemporary French philosopher and theologian Claude Tresmontant (1925-97).
In medias res: the life of Claude de Seyssel -- The scholar diplomat -- The translator of histories -- Seyssel in Italy : a scholar looks at war -- The scholar and the state -- Seyssel, the church, and the ideal prelate.
