Chaotically spiking canards in an excitable system with 2D inertial fast manifolds

PACS:05.45.−a, 42.65.−k, 42.65.SfWe introduce a new class of excitable systems with two-dimensional fast dynamics that includes inertia. A novel transition from excitability to relaxation oscillations is discovered where the usual Hopf bifurcation is followed by a cascade of period doubled and chaotic small excitable attractors and, as they grow, by a new type of canard explosion where a small chaotic background erratically but deterministically triggers excitable spikes. This scenario is also found in a model for a nonlinear Fabry-Perot cavity with one pendular mirror.This work was partially funded by the European Union ILIAS Project (No. RII3-CT-2003-506222), the CSIC— Spain Grant HIELOCRIS (No. 200530F0052).Peer reviewe

Vicissitudes de deux oeufs. Principe de raison et principe des indiscernables dans les premiers écrits de Leibniz

Il saggio discute la genesi del principio degli indiscernibili di G.W. Leibniz, nel contesto di una più ampia ricostruzione storica della formazione della dottrina monadologica. Viene contestata l'illusione di una continuità dottrinale forte di Leibniz dai primi scritti sul principio di individuazione alla maturità, seguendo un esempio tipicamente usato da Leibniz: quello di due uova esattamente simili. Per il giovane Leibniz, tale somiglianza totale è realmente possibile. Per il Leibniz maturo, tale somiglianza totale è metafisicamente impossibile, ma è costantemente presupposta dallo spirito umano quando tale spirito considera gli oggetti geometricamente. il problema centrale che conduce alla formazione del principio degli indiscernibili è dunque quello delle differenze prospettiche tra geometria, scienza naturale e metafisica, un problema centrale nel confronto leibniziano con il cartesianesim

L’ammirazione in Cartesio e Spinoza. Classificazione degli affetti e costituzione dello spazio antropologico

The status of «Admiration» in Descartes and Spinoza is illustrated by F. Piro as an index of different anthropological options, concerning the relationships between emotions and rationality and the role that they play in social, political and religious behavior. The differences in metaphysical assumptions that separate the two thinkers as well as the internal evolution of their thinking are enucleated under such perspective. In the background there are at least three main philosophical issues: (i) the classic issue of the «primary» emotions (also in the current form of a question about the «anthropological universals»); (ii) the issue of the existence and nature of moral sentiments and, at the end, (iii) that of the status of the «admirable» or «amazing» in the age of the scientific revolution

Il Retore Interno Immaginazioni E Passioni All'alba Dell'etáa Moderna

this book concerns the debates on the functions of "imagination" (phantasia, imaginatio) in the arousal of passions in the Aristotelian and post-Aristotelian traditions till the XVIIth Century. The simple fact that often a mental representation is followed by pleasure or sorrow and that these emotions can cause actions, became progressively part of a wider theory of animal and human behaviour. In the case of human behaviour, the "force of imagination" became a kind of general justification of all kind of anomic and irregular behaviour and beliefs, including true paranormal conditions of the body. The book recapitulates the main evolution of this way of seeing passions - from Aristotle to Avicenna and his Latin followers - till the age of the authors who see the inner work of "imagination" as a constant danger for human reason, and imagination itself as faculty to control with care for its propension to be the "advocate" of the "inferior part of the soul", such as Gianfrancesco Pico, Juan Luis Vivés, Pierre Charron, Blaise Pascal and a large part of the French Augustinian Moral Philosophers

Redshift determination in the X-ray band of gamma-ray bursts

If gamma-ray bursts originate in dense stellar forming regions, the interstellar material can imprint detectable absorption features on the observed X-ray spectrum. Such features can be detected by existing and planned X-ray satellites, as long as the X-ray afterglow is observed after a few minutes from the burst. If the column density of the interstellar material exceeds ~10^{23} cm^{-2} there exists the possibility to detect the K_alpha fluorescent iron line, which should be visible for more than one year, long after the X-ray afterglow continuum has faded away. Detection of these X-ray features will make possible the determination of the redshift of gamma-ray bursts even when their optical afterglow is severely dimmed by extinction.Comment: 15 pages with 5 figures. Submitted to Ap

Acute diabetes complications

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Triggers for atrial fibrillation. the role of anxiety

Atrial fibrillation (AF) is the most widely recognized arrhythmia. Systemic arterial hypertension, diabetes, obesity, heart failure, and valvular heart diseases are major risk factors for the onset and progression of AF. Various studies have emphasized the augmented anxiety rate among AF patients due to the poor quality of life; however, little information is known about the possibility of triggering atrial fibrillation by anxiety. +e present review sought to underline the possible pathophysiological association between AF and anxiety disorders and suggests that anxiety can be an independent risk factor for AF, acting as atrigger, creating an arrhythmogenic substrate, and modulating the autonomic nervous system.+e awareness of the role of anxietydisorders as a risk factor for AF may lead to the development of new clinical strategies for the management of AF

Bryo-Activities: A Review on How Bryophytes Are Contributing to the Arsenal of Natural Bioactive Compounds against Fungi

Usually regarded as less evolved than their more recently diverged vascular sisters, which currently dominate vegetation landscape, bryophytes seem having nothing to envy to the defensive arsenal of other plants, since they had acquired a suite of chemical traits that allowed them to adapt and persist on land. In fact, these closest modern relatives of the ancestors to the earliest terrestrial plants proved to be marvelous chemists, as they traditionally were a popular remedy among tribal people all over the world, that exploit their pharmacological properties to cure the most different diseases. The phytochemistry of bryophytes exhibits a stunning assortment of biologically active compounds such as lipids, proteins, steroids, organic acids, alcohols, aliphatic and aromatic compounds, polyphenols, terpenoids, acetogenins and phenylquinones, thus it is not surprising that substances obtained from various species belonging to such ancestral plants are widely employed as antitumor, antipyretic, insecticidal and antimicrobial. This review explores in particular the antifungal potential of the three Bryophyta divisions\u2014mosses (Musci), hornworts (Anthocerotae) and liverworts (Hepaticae)\u2014to be used as a sources of interesting bioactive constituents for both pharmaceutical and agricultural areas, providing an updated overview of the latest relevant insights