Search results for "catastro"

Truncated thermalization of incoherent optical waves through supercontinuum generation in photonic crystal fibers

2013

We revisit the process of optical wave thermalization through supercontinuum generation in photonic crystal fibers. We report theoretically and numerically a phenomenon of `truncated thermalization': The incoherent optical wave exhibits an irreversible evolution toward a Rayleigh-Jeans thermodynamic equilibrium state characterized by a compactly supported spectral shape. The theory then reveals the existence of a frequency cut-off which regularizes the ultraviolet catastrophe inherent to ensembles of classical nonlinear waves. This phenomenon sheds new light on the mechanisms underlying the formation of bounded supercontinuum spectra in photonic crystal fibers.

Condensation and thermalization of classsical optical waves in a waveguide

2011

http://pra.aps.org/; International audience; We consider the long-term evolution of a random nonlinear wave that propagates in a multimode optical waveguide. The optical wave exhibits a thermalization process characterized by an irreversible evolution toward an equilibrium state. The tails of the equilibrium distribution satisfy the property of energy equipartition among the modes of the waveguide. As a consequence of this thermalization, the optical field undergoes a process of classical wave condensation, which is characterized by a macroscopic occupation of the fundamental mode of the waveguide. Considering the nonlinear Schrödinger equation with a confining potential, we formulate a wav…

DNA Damage Response and the Balance Between Cell Survival and Cell Death

2009

DNA damage induces the activation of a cascade of kinases that trigger the DNA damage response (DDR). Downstream are targets that either help cells to survive or undergo cell death. DNA damage-induced cell death is executed by apoptosis, necrosis, mitotic catastrophe, and autophagy. Of these different forms of cell inactivation, apoptosis is often the main route of cell death following DNA damage. Cells undergo apoptosis upon genotoxic stress via the death receptor and/or the intrinsic mitochondrial damage pathway, with p53 and AP-1 involved decisively. Not every type of DNA damage induces apoptosis. Many DNA lesions are tolerated by the cell, some are mutagenic without being toxic and some…

Revising the negative meaning of chronic pain – a phenomenological study

2016

Revising the negative meaning of chronic pain : A phenomenological study

2014

Objectives Chronic pain may disable the body, depress the mind and ruin the quality of life. The aim of this study was to use the participants’ personal experiences to explore the meaning of the experience of chronic pain and to find successful ways to manage chronic pain. Methods Thirty-four participants with chronic pain were interviewed. The transcribed interviews were analysed using Giorgi’s phenomenological method consisting of four phases: (1) reading the transcriptions several times, (2) discriminating meaning units, (3) collecting meaning units into groups and (4) the synthesis. Results The participants stated that the key to managing chronic pain was to reconsider the individual me…

L'alluvione di Palermo del 1557 tra rischio idrogeologico, speculazione edilizia e piani di ricostruzione

2014

Il saggio indaga, attraverso nuove significative fonti documentarie, cause e dinamiche di uno dei più drammatici eventi catastrofici che abbiano colpito la capitale del Regno di Sicilia, l'alluvione di Palermo del 1557, adesso ricondotta a scelte ingegneristiche errate e a interventi di prevenzione malfatti. Il contributo analizza, poi, gli importanti interventi di rinnovamento urbano che vennero intrapresi nell'ambito del piano di ricostruzione portato avanti congiuntamente dall'autorità viceregia e municipale.

Structural and Dynamical Complexities of Risk and Catastrophe Systems: an Approach by System Dynamics Modelling

2009

Risk and catastrophe are complex systems. Within the scope of this paper, we focus our attention on structural and dynamic complexities of catastrophes and on the possibility of modelling and simulating its double complexity with a formal and methodological framework: the General Systems Theory and System Dynamics modelling. Then we briefly propose a model of urban catastrophe related to a flood. After we propose some ways of research allowing exceeding the limits related to the modelling.

Les comportements de protection face au risque naturel : de la résistance à l’engagement

2011

An adequate risk management requires taking into account all the categories of stakeholders, including the exposed populations. Nowadays, one difficulty is to involve these populations and consequently to understand their reactions face to the eventuality of a disaster's occurrence. Several issues must be addressed: how is the representation of risk built up ? How do people develop adaptive strategies towards risk ? And above all, how is it possible to ensure an increase in behaviours suited for prevention and protection ? After drawing up a report on the research in this area, we will discuss the limitations of a persuasive communication, in order to better understand the interest of a bin…

Premessa

2012

Le storie dell’Europa meridionale in generale, e della Sicilia in particolare, offrono un panorama variegato di distruzioni e di ricostruzioni documentate, più e meno recenti, tali da consentire l’elaborazione di confronti e di casistiche, mentre la verifica di nodi problematici, delle mutazioni improvvise, così come delle spinte in avanti, delle sacche di resistenza o della ricerca di nuovi equilibri, diventano anche un presupposto e un incentivo per esplorare nuove possibilità di trasformazione.

OLTRE L’UMANO. APOCALISSI E COSMOGONIA NEL PIANETA IRRITABILE DI PAOLO VOLPONI

2021

Il saggio rilegge "Il pianeta irritabile" come storia di una cosmogonia, in cui le istanze fantascientifiche convivono con le ragioni allegoriche e con le suggestioni dell’antropologia. "Il pianeta irritabile" ha inizio dopo una catastrofe atomica, quando un diluvio di acqua, petrolio, sabbia e madreperla cancella il «vecchio ordine» basato sulla sovranità dell’umano e sulla logica artificiale del capitale. Il nano Mamerte, l’oca Plan Calcule, l’elefante Roboamo, sotto la guida del babbuino Epistola, compiono un viaggio alla ricerca di una possibile salvezza. Il passaggio dal caos dell’apocalisse alla rifondazione di un’«immortalità selvaggia» è scandito da prove iniziatiche, da lotte e da …