Unraveling the complex metabolic nature of astrocytes.

Since the initial description of astrocytes by neuroanatomists of the nineteenth century, a critical metabolic role for these cells has been suggested in the central nervous system. Nonetheless, it took several technological and conceptual advances over many years before we could start to understand how they fulfill such a role. One of the important and early recognized metabolic function of astrocytes concerns the reuptake and recycling of the neurotransmitter glutamate. But the description of this initial property will be followed by several others including an implication in the supply of energetic substrates to neurons. Indeed, despite the fact that like most eukaryotic non-proliferative cells, astrocytes rely on oxidative metabolism for energy production, they exhibit a prominent aerobic glycolysis capacity. Moreover, this unusual metabolic feature was found to be modulated by glutamatergic activity constituting the initial step of the neurometabolic coupling mechanism. Several approaches, including biochemical measurements in cultured cells, genetic screening, dynamic cell imaging, nuclear magnetic resonance spectroscopy and mathematical modeling, have provided further insights into the intrinsic characteristics giving rise to these key features of astrocytes. This review will provide an account of the different results obtained over several decades that contributed to unravel the complex metabolic nature of astrocytes that make this cell type unique.

The Complaint of nature, by Alain de Lille, translated from the Latin by Douglas M. Moffat

[De planctu naturae (anglais). 1908]

Conservation banking and the economization of nature : an institutional analysis

During the last decade, conservation banking mechanisms have emerged in the environmental discourse as new market instruments to promote biodiversity conservation. Compensation was already provided for in environmental law in many countries, as the last step of the mitigation hierarchy. The institutional arrangements developed in this context have been redefined and reshaped as market-based instruments (MBIs). As such, they are discursively disentangled from the complex legal-economic nexus they are part of. Monetary transactions are given prominence and tend to be presented as stand alone agreements, whereas they take place in the context of prescriptive regulations. The pro-market narrative featuring conservation banking systems as market-like arrangements as well as their denunciation as instances of nature commodification tend to obscure their actual characteristics. The purpose of this paper is to describe the latter, adopting an explicitly analytical stance on these complex institutional arrangements and their performative dimensions. Beyond the discourse supporting them and notwithstanding the diversity of national policies and regulatory frameworks for compensation, the constitutive force of these mechanisms probably lies in their ability to redefine control, power and the distribution of costs and in their impacts in terms of land use rather than in their efficiency.

THE CONCEPT OF 'NATURE' IN ARISTOTLE, AVICENNA AND AVERROES

This study is concerned with 'nature' specifically as the subject-matter of physics, or natural science, as described by Aristotle in his "Physics". It also discusses the definitions of nature, and more specifically physical nature, provided by Avicenna (d. 1037) and Averroes (d. 1198) in their commentaries on Aristotle's "Physics". Avicenna and Averroes share Aristotle's conception of nature as a principle of motion and rest. While according to Aristotle the subject matter of physics appears to be nature, or what exists by nature, Avicenna believes that it is the natural body, and Averroes holds that the subject matter of physics or natural science consists in the natural things, in what constitutes a slight shift in focus.

BRUNO BAUCH AND THE COMPREHENSIBILITY OF NATURE

ABSTRACT The aim of this paper is to discuss how Bruno Bauch deals with the problem of the coordination between empirical concepts and spatiotemporal objects. We shall argue that Bauch reformulates the Kantian distinction between concepts and intuitions by means of a philosophical consideration of differential calculus and that he thereby explains the possibility of such coordination, avoiding certain difficulties of the Kantian doctrine.

The Literary relations between La Fontaine and the "Astrée" of Honoré d'Urfé : a dissertation presented to the faculty of the department of philosophy of the university of Pennsylvania in partial fulfilment of the requirements for the degree of doctor of philosophy / by Walther P. Fischer

Collection : Publications of the University of Pennsylvania ; n° 6