Publications of 2020

CRAN R code to analyze disruption of plant-pollinator networks for the article: Disruption of biological processes in the Anthropocene: the case of phenological mismatch

Symmetries play a major role in physics, in particular since the work by E. Noether and H. Weyl in the first half of last century. Herein, we briefly review their role by recalling how symmetry changes allow to conceptually move from classical to relativistic and quantum physics. We then introduce our ongoing theoretical analysis in biology and show that symmetries play a radically different role in this discipline, when compared to those in current physics. By this comparison, we stress that symmetries must be understood in relation to conservation and stability properties, as represented in the theories. We posit that the dynamics of biological organisms, in their various levels of organization, are not “just” processes, but permanent (extended, in our terminology) critical transitions and, thus, symmetry changes. Within the limits of a relative structural stability (or interval of viability), qualitative variability is at the core of these transitions.

Keywords: Coherent structures, Critical transitions, downward causation, Hidden variables, Levels of organization, Symmetries, Systems biology

Most mathematical modeling in biology relies either implicitly or explicitly on the epistemology of physics. The underlying conception is that the historicity of biological objects would not matter to understand a situation here and now, or, at least, historicity would not impact the method of modeling. We analyze that it is not the case with concrete examples. Historicity forces a conceptual reconfiguration where equations no longer play a central role. We argue that all observations depend on objects defined by their historical origin instead of their relations as in physics. Therefore, we propose that biological variations and historicity come first, and regularities are constraints with limited validity in biology. Their proper theoretical and empirical use requires specific rationales.

Keywords: Historicity, Organization, Epistemology, Mathematical modeling, Constraints

We address the identity of biological organisms at play in experimental and modeling practices. We first examine the central tenets of two general conceptions, and we assess their respective strengths and weaknesses. The historical conception, on the one hand, characterizes organisms’ identity by looking at their past, and specifically at their genealogical connection with a common ancestor. The relational conception, on the other hand, interprets organisms’ identity by referring to a set of distinctive relations between their parts, and between the organism and its environment. While the historical and relational conceptions are understood as opposed and conflicting, we submit that they are also fundamentally complementary. Accordingly, we put forward a hybrid conception, in which historical and relational (and more specifically, organizational) aspects of organisms’ identity sustain and justify each other. Moreover, we argue that organisms’ identity is not only hybrid but also bounded, insofar as the compliance with specific identity criteria tends to vanish as time passes, especially across generations. We spell out the core conceptual framework of this conception, and we outline an original formal representation. We contend that the hybrid and bounded conception of organisms’ identity suits the epistemological needs of biological practices, particularly with regards to the generalization and reproducibility of experimental results, and the integration of mathematical models with experiments.

L’économie industrielle a pris forme entre la fin du XVIIIe siècle et le XIXe siècle – d’abord en Europe occidentale puis en Amérique du Nord. Outre les productions techniques, elle aura conduit à des productions technologiques – mobilisant des sciences pour produire des biens industriels – : comme Marx l’aura montré en 1857, le capitalisme fait du savoir et de sa valorisation économique son élément premier. <br> La physique de Newton et la métaphysique qui l’accompagne sont à l’origine du cadre épistémique (au sens de Michel Foucault) et épistémologique (au sens de Gaston Bachelard) de cette grande transformation – qui est la condition de ce que Karl Polanyi appellera lui-même « la grande transformation ». Dans cette transformation, l’otium (le temps de loisirs productifs) se soumet au negotium (les affaires du monde). Pendant ce temps, les mathématiques sont appliquées à travers des machines à calculer toujours plus puissantes et performatives – appelées computers après la deuxième guerre mondiale. <br> Après des précurseurs tels que Nicholas Georgescu-Roegen, lui-même inspiré par Alfred Lotka, nous soutiendrons dans le présent ouvrage que l’économie politique, dans ce qui est appelé l’ère Anthropocène (thématisée en 2000 par Paul Krutzen, et dont les caractéristiques ont été décrites par Vladimir Vernadsky dès 19263) est un défi qui nécessite un réexamen fondamental de ces cadres épistémiques et épistémologiques. <br> Avec Darwin, les êtres vivants sont devenus partie intégrante d’un processus historique en constant devenir. Chez l’homme, les savoirs sont une partie de ce processus qui est performative, au double sens de ce mot : à la fois au sens de l’efficience et au sens de la prescription. Ce processus devient exosomatique, c’est à dire extra-corporel, comme le montre Lotka, qui façonne et remodèle les modes de vie afin, notamment, de limiter les effets négatifs des nouveautés techniques.

The industrial economy took shape between the late eighteenth century and the nineteenth century, initially in Western Europe and then in North America. Besides technical production, it involves technological production – the integration of sciences in order to produce indus-trial goods –, to the strict extent that, as Marx showed, capitalism makes knowledge and its economic valorization its primary element. <br> Newton’s physics and the metaphysics that goes with it originated the epistemic (in Michel Foucault’s sense) and epistemological (in Gaston Bachelard’s sense) framework of this great transformation. In this transformation, otium (productive leisure time) submits to negotium (worldly affairs, business). All along, mathematics has been applied with ever more powerful and performative calculating machines. <br> After precursors such as Nicholas Georgescu-Roegen, himself inspired by Alfred Lotka, we maintain that political economy in what is now called the Anthropocene (whose features were delineated by Vladimir Vernadsky in 1926) is a challenge that requires a fundamental reconsideration of these epistemic frameworks and epistemological frameworks. With Dar-win, living beings became part of a historical process of becoming. In humans, knowledge is a performative part of this process that shapes and reshapes lifestyles in order to tame the im-pact of technical novelties.

We aimed to a) determine whether BPA showed effects on the developing rat mammary gland using new quantitative and established semiquantitative methods in two laboratories, b) develop a software tool for automatic evaluation of quantifiable aspects of the mammary ductal tree, and c) compare those methods. Conclusions: Both the semiquantitative and the quantitative methods revealed nonmonotonic effects of BPA. The quantitative unsupervised analysis used 91 measurements and produced the most striking nonmonotonic dose–response curves. At all time points, lower doses resulted in larger effects, consistent with the core study, which revealed a significant increase of mammary adenocarcinoma incidence in the stop-dose animals at the lowest BPA dose tested.

Turing distingue soigneusement l’imitation de la modélisation d’un phénomène. Cette dernière vise à saisir la structure causale du phénomène étudié. En biologie, il n’y a cependant pas de cadre théorique bien établi pour encadrer la pratique de modélisation. Nous partons de l’articulation entre la compréhension du vivant et la thermodynamique, en particulier le second principe. Ceci nous conduira à expliciter les défis théoriques et épistémologiques pour la compréhension mathématique du vivant. En particulier, l’historicité du vivant est un défi rarement abordé explicitement dans ce domaine. Nous pensons que ce défi nécessite un renversement complet de l’épistémologie de la physique afin d’aborder de manière théoriquement précise les organismes vivants. Ce changement épistémologique est pertinent tant pour la pratique théorique que pour l’interprétation des protocoles et résultats expérimentaux.

Keywords: anti-entropie, entropie, épistémologie, historicité, morphogenèse, Turing