Macroscopic fluctuations theory of aerogel dynamics

We consider the thermodynamic potential describing the macroscopic fluctuation of the current and local energy of a general class of Hamiltonian models including aerogels. We argue that this potential is neither analytic nor strictly convex, a property that should be expected in general but missing from models studied in the literature. This opens the possibility of describing in terms of a thermodynamic potential non-equilibrium phase transitions in a concrete physical context. This special behaviour of the thermodynamic potential is caused by the fact that the energy current is carried by particles which may have arbitrary low speed with sufficiently large probability.Comment: final versio

Drastic fall-off of the thermal conductivity for disordered lattices in the limit of weak anharmonic interactions

We study the thermal conductivity, at fixed positive temperature, of a disordered lattice of harmonic oscillators, weakly coupled to each other through anharmonic potentials. The interaction is controlled by a small parameter $\epsilon > 0$. We rigorously show, in two slightly different setups, that the conductivity has a non-perturbative origin. This means that it decays to zero faster than any polynomial in $\epsilon$ as $\epsilon\rightarrow 0$. It is then argued that this result extends to a disordered chain studied by Dhar and Lebowitz, and to a classical spins chain recently investigated by Oganesyan, Pal and Huse.Comment: 21 page

The phonon Boltzmann equation, properties and link to weakly anharmonic lattice dynamics

For low density gases the validity of the Boltzmann transport equation is well established. The central object is the one-particle distribution function, $f$, which in the Boltzmann-Grad limit satisfies the Boltzmann equation. Grad and, much refined, Cercignani argue for the existence of this limit on the basis of the BBGKY hierarchy for hard spheres. At least for a short kinetic time span, the argument can be made mathematically precise following the seminal work of Lanford. In this article a corresponding programme is undertaken for weakly nonlinear, both discrete and continuum, wave equations. Our working example is the harmonic lattice with a weakly nonquadratic on-site potential. We argue that the role of the Boltzmann $f$-function is taken over by the Wigner function, which is a very convenient device to filter the slow degrees of freedom. The Wigner function, so to speak, labels locally the covariances of dynamically almost stationary measures. One route to the phonon Boltzmann equation is a Gaussian decoupling, which is based on the fact that the purely harmonic dynamics has very good mixing properties. As a further approach the expansion in terms of Feynman diagrams is outlined. Both methods are extended to the quantized version of the weakly nonlinear wave equation. The resulting phonon Boltzmann equation has been hardly studied on a rigorous level. As one novel contribution we establish that the spatially homogeneous stationary solutions are precisely the thermal Wigner functions. For three phonon processes such a result requires extra conditions on the dispersion law. We also outline the reasoning leading to Fourier's law for heat conduction.Comment: special issue on "Kinetic Theory", Journal of Statistical Physics, improved versio

Large deviations of lattice Hamiltonian dynamics coupled to stochastic thermostats

We discuss the Donsker-Varadhan theory of large deviations in the framework of Hamiltonian systems thermostated by a Gaussian stochastic coupling. We derive a general formula for the Donsker-Varadhan large deviation functional for dynamics which satisfy natural properties under time reversal. Next, we discuss the characterization of the stationary state as the solution of a variational principle and its relation to the minimum entropy production principle. Finally, we compute the large deviation functional of the current in the case of a harmonic chain thermostated by a Gaussian stochastic coupling.Comment: Revised version, published in Journal of Statistical Physic

Metaphorical and interlingual translation in moving organizational practices across languages

Organizational scholars refer to translation as a metaphor in order to describe the transformation and movement of organizational practices across institutional contexts. However, they have paid relatively little attention to the challenges of moving organizational practices across language boundaries. In this conceptual paper, we theorize that when organizational practices move across contexts that differ not only in terms of institutions and cultures but also in terms of languages, translation becomes more than a metaphor; it turns into reverbalization of meaning in another language. We argue that the meeting of languages opens up a whole new arena for translator agency to unfold. Interlingual and metaphorical translation are two distinct but interrelated forms of translation that are mutually constitutive. We identify possible constellations between interlingual and metaphorical translation and illustrate agentic translation with published case examples. We also propose that interlingual translation is a key resource in the discursive constitution of multilingual organizations. This paper contributes to the stream of research in organization studies that has made translation a core aspect of its inquiry

Riflessioni su alcune scelte traduttive in lingua inglese (Morris, Tinker, Tolkien, Heaney e Porter)

This essay takes into account some English translations of the Old English poem Beowulf. Matter of specific investigation is the passage of the coming of Grendel to the Danes' court Heorot. As the translations of Beowulf are countless, only specific and emblematic cases – both in prose and verse – are analysed. Then, the translations by William Morris, Chancey Brewster Tinker, J.R.R. Tolkien, Seamus Heaney and John Porter are compared trying to ascertain the approach of those translators to the Old English text and furthermore the intentions they had in rendering the poem into Modern English. The big problem that all the translators consciously tackled was the chronological and linguistic distance of Beowulf that had to be solved in some way. Choices and strategies differ from one version to another, but every solution demonstrates a specific attention to the musicalness of the original together with a deep awareness for the tradition that the Old English poem embodies

Introduction: self-translating, from minorisation to empowerment

This introductory chapter discusses the implications of self-translation in multilingual contexts in Europe, aiming at mapping out innovative perspectives to the study of power and, by so doing, empowering self-translation. We start by critically engaging with the ‘cultural’ and ‘power turns’ in translation studies, as a way of delineating what the particularities of self-translation are when practised by author-translators in multilingual spaces. Focusing on the European milieu, defined broadly in terms of its geographies, we then discuss multilingualism, cultural awareness and ethnic diversity as staple terms in both academic and political ideologies across Europe, emphasising that one of the aspects of multilingualism is precisely the power differentials between languages and cultures. We explore these unequal power relations and centre–periphery dichotomies of Europe’s ‘minorised’ languages, literatures and cultures, suggesting the usage of ‘minorised’ in preference to the others discussed, inasmuch as it highlights both hegemonic power hierarchies and also the continual resistance to them. This is followed by a brief overview of the emerging debates in the subdiscipline of self-translation in recent times. It is within them that we situate our contribution, arguing that the self-translators’ double affiliation as authors and translators turns them into powerful cultural and ideological mediators and places them in a privileged position to challenge (or submit to) power. Here another term, ‘self-censorship,’ is suggested as invaluable to self-translation studies where self-editing often occurs before translation is begun. Finally, the introduction presents the organisation of the book and the main ideas discussed by the 11 authors in their individual chapters

Phase fluorometric method for determination of standard lifetimes

Rayleigh scatterers have long been used as standards for fluorescence lifetime determinations, but they have many drawbacks, including the well-known “color effect ’. To avoid these problems, various fiuorophores have been used as standards. Unfortunately, the lifetimes of these compounds are not agreed upon to better than 5%, and the compounds cited in the literature do not fully cover the 250–850 nm band of common fluorescence emission. We describe a multifrequency phase fluorometric method for accurately determining the lifetimes of monoexponential fluorophores (standards) without reference to another standard. Results are shown for some widely used standard fluorophores and some recently developed compounds. An Independent test of the accuracy of the method based on quenching experiments is presented. © 1988, American Chemical Society. All rights reserved

Doxapram versus placebo in preterm newborns: a study protocol for an international double blinded multicentre randomized controlled trial (DOXA-trial)

Abstract Background Apnoea of prematurity (AOP) is one of the most common diagnoses among preterm infants. AOP often leads to hypoxemia and bradycardia which are associated with an increased risk of death or disability. In addition to caffeine therapy and non-invasive respiratory support, doxapram might be used to reduce hypoxemic episodes and the need for invasive mechanical ventilation in preterm infants, thereby possibly improving their long-term outcome. However, high-quality trials on doxapram are lacking. The DOXA-trial therefore aims to investigate the safety and efficacy of doxapram compared to placebo in reducing the composite outcome of death or severe disability at 18 to 24 months corrected age. Methods The DOXA-trial is a double blinded, multicentre, randomized, placebo-controlled trial conducted in the Netherlands, Belgium and Canada. A total of 396 preterm infants with a gestational age below 29 weeks, suffering from AOP unresponsive to non-invasive respiratory support and caffeine will be randomized to receive doxapram therapy or placebo. The primary outcome is death or severe disability, defined as cognitive delay, cerebral palsy, severe hearing loss, or bilateral blindness, at 18–24 months corrected age. Secondary outcomes are short-term neonatal morbidity, including duration of mechanical ventilation, bronchopulmonary dysplasia and necrotising enterocolitis, hospital mortality, adverse effects, pharmacokinetics and cost-effectiveness. Analysis will be on an intention-to-treat principle. Discussion Doxapram has the potential to improve neonatal outcomes by improving respiration, but the safety concerns need to be weighed against the potential risks of invasive mechanical ventilation. It is unknown if the use of doxapram improves the long-term outcome. This forms the clinical equipoise of the current trial. This international, multicentre trial will provide the needed high-quality evidence on the efficacy and safety of doxapram in the treatment of AOP in preterm infants. Trial registration ClinicalTrials.gov NCT04430790 and EUDRACT 2019-003666-41. Prospectively registered on respectively June and January 2020