Non-meanfield deterministic limits in chemical reaction kinetics far from equilibrium

A general mechanism is proposed by which small intrinsic fluctuations in a system far from equilibrium can result in nearly deterministic dynamical behaviors which are markedly distinct from those realized in the meanfield limit. The mechanism is demonstrated for the kinetic Monte-Carlo version of the Schnakenberg reaction where we identified a scaling limit in which the global deterministic bifurcation picture is fundamentally altered by fluctuations. Numerical simulations of the model are found to be in quantitative agreement with theoretical predictions.Comment: 4 pages, 4 figures (submitted to Phys. Rev. Lett.

Numerical Evaluation of the Accuracy and Stability Properties of High-order Direct Stokes Solvers with or without Temporal Splitting

The temporal stability and effective order of two different direct high-order Stokes solvers are examined. Both solvers start from the primitive variables formulation of the Stokes problem, but are distinct by the numerical uncoupling they apply on the Stokes operator. One of these solvers introduces an intermediate divergence free velocity for performing a temporal splitting (J. Comput. Phys. [1991] 97, 414-443) while the other treats the whole Stokes problem through the evaluation of a divergence free acceleration field (C.R. Acad. Sci. Paris [1994] 319 Serie I, 1455-1461; SIAM J. Scient. Comput. [2000] 22(4), 1386-1410). The second uncoupling is known to be consistent with the harmonicity of the pressure field (SIAM J. Scient. Comput. [2000] 22(4), 1386-1410). Both solvers proceed by two steps, a pressure evaluation based on an extrapolated in time (of theoretical order Je) Neumann condition, and a time implicit (of theoretical order Ji) diffusion step for the final velocity. These solvers are implemented with a Chebyshev mono-domain and a Legendre spectral element collocation schemes. The numerical stability of these four options is investigated for the sixteen combinations of (Je,Ji), 1 ≤ Je, Ji ≤

New Jersey Radium Dial Workers and the Dynamics of Occupational Disease Litigation in the Early Twentieth Century, The

Between 1917 and 1923 over 800 women worked for the United States Radium Corporation ( USRC ) in Orange, New Jersey handpainting wrist-watch faces with a substance made luminescent by radioactive materials. While these workers were exposed to injurious, even mortal, levels of radiation, less than a dozen received any compensation for their injuries. These features compounded the workers\u27 legal problems once they entered the formal legal system by dramatically complicating attempts to prove causation, by raising the specter of the statute of limitations defense, and by playing a major role in the settlement negotiation process. As a consequence, even when some women did resort to the formal legal system for relief, they faced hurdles endemic to the legal process and a dynamic of litigation that favored and rewarded repeat-player defendants. This article examines the radium dial-painter episode in four main sections. The first section presents a basic, historical narrative of the dial-painter litigation. The second section identifies and explores the medical, legal, and sociological reasons why so few cases entered the legal system. In the third section, we will examine the legal doctrines that governed the workers\u27 claims against USRC. In the final section, we will examine how the basic architecture of the legal system presented conditions that dramatically affected the chances of success and recovery of the few claimants who entered the legal system and allowed powerful defendants to fashion to their benefit the overall course and outcome of the litigation

Dynamics of the Freezing Front During the Solidification of a Colloidal Alumina Aqueous Suspension: In Situ X-Ray Radiography, Tomography, and Modeling

International audienceIce templating of colloidal suspension is gaining interest in material science because it offers the possibility to shape advanced materials, and in particular porous ceramics. Recent investigations on this peculiar process show that a correlation between the morphology of the frozen suspension and the velocity of the freezing front do exist. The dynamics of the freezing front of a colloidal suspension of alumina is investigated in the present study by experimental tests, finite element numerical analysis and theoretical analytical calculations. The experimental tests are carried out by in situ X-ray radiography (investigation of the dynamics of the freezing front) and tomography (investigation of the resulting morphology of the frozen suspension). The finite element model is a continuous properties model; it is used for investigating the dynamics and the shape of the freezing front. The analytical model is based on the two-phase Stefan problem. We propose a solution for the dynamics of the solidification front based on the calculation of the diffusivity as a function of the particle fraction and local temperature

Large-eddy simulation of the lid-driven cubic cavity flow by the spectral element method

This paper presents the large-eddy simulation of the lid-driven cubic cavity flow by the spectral element method (SEM) using the dynamic model. Two spectral filtering techniques suitable for these simulations have been implemented. Numerical results for Reynolds number $\text{Re}=12'000$ are showing very good agreement with other experimental and DNS results found in the literature

Villa Sint Gertrudis te Landen (Landen, provincie Vlaams-Brabant). Studieopdracht naar een archeologische evaluatie en waardering

In opdracht van het agentschap Onroerend Erfgoed evalueerde Condor Archaeological Research bvba van januari 2012 tot oktober 2012 de erfgoedwaarde van de site die bekend staat als Villa Sint-Gertrudis te Landen, provincie Vlaams-Brabant. Ten oosten hiervan werd in 2010 een soortgelijke studie uitgevoerd naar twee mottes, een bron en de Sint-Gertrudiskerk, waaruit bleek dat in het in dit rapport beschreven gebied van circa 23 ha mogelijk de restanten van een Romeinse villa en bijhorende off site fenomenen aanwezig waren. In dit rapport worden de resultaten van de studieopdracht beschreven en wordt het gebied gewaardeerd volgens de beschermingscriteria opgesteld door het agentschap Onroerend Erfgoed. Behalve enkele losse vondsten waarvan het onduidelijk is of deze door bemesting van op grote afstand, dan wel lokaal vanuit de onmiddellijke omgeving van het plangebied afkomstig zijn, zijn er tijdens dit onderzoek geen archeologische vindplaatsen vastgesteld. De verwachtte villa blijkt, met een vrij grote zekerheid, niet aanwezig te zijn binnen de grenzen van het plangebied. Er werd dus ook niet aanbevolen dit gebied in aanmerking te nemen voor archeologische bescherming

Dynamics on Networks of Manifolds

We propose a precise definition of a continuous time dynamical system made up of interacting open subsystems. The interconnections of subsystems are coded by directed graphs. We prove that the appropriate maps of graphs called graph fibrations give rise to maps of dynamical systems. Consequently surjective graph fibrations give rise to invariant subsystems and injective graph fibrations give rise to projections of dynamical systems

Kesselberg te Leuven/Holsbeek (Leuven en Holsbeek, provincie Vlaams-Brabant). Studieopdracht naar een archeologische evaluatie en waardering

In opdracht van het agentschap Onroerend Erfgoed evalueerde Condor Archaeological Research bvba tussen januari 2012 en februari 2013 de archeologische site van de Kesselberg te Leuven en Holsbeek (prov. Vlaams-Brabant) in functie van de mogelijke opmaak van een archeologisch beschermingsdossier. Door de jarenlange prospecties van A. Boschmans en de opgravingen in 1959 door J. Mertens (Nationale Dienst voor Opgravingen) stond de Kesselberg reeds lang bekend als een archeologisch waardevolle zone met o.a. de aanwezigheid van een versterking uit de ijzertijd, verschillende oudere vondsten en de mogelijke aanwezigheid van kasteel Kesselstein, dat teruggaat tot de 11e eeuw. Vandaag bestaat het gebied van circa 20 ha voornamelijk uit bos met hier en daar een stuk open weiland. Enkele percelen zijn bebouwd. In het voorliggend rapport worden de resultaten van de studieopdracht beschreven. Tussen het begin van de 20e eeuw en het midden van de jaren 70 is meer dan anderhalve hectare van de Kesselberg weggegraven. Met dank aan Boschmans zijn er rijke archeologische gegevens bekend over het afgegraven gedeelte, maar zeer veel relicten zijn zeker ook ongedocumenteerd verdwenen. Tot in het midden van de jaren 70 liep over de Kesselberg een groot en intens gebruikt motorcross parcours. Veldwaarnemingen en geofysisch onderzoek brachten de resten van die diepe verstoringen aan het licht en ook van oudere gebouwen. Volgens het proefsleuvenonderzoek, waarbij verschillende grondsporen zijn vastgesteld, hadden deze verstoringen en de natuurlijke erosie in sommige zones al bij al toch nog betrekkelijk weinig impact. Grote delen van het terrein bleken nog onverstoord of zwak verstoord. In dit gebied is dus zeker nog heel wat informatie aanwezig die beter inzicht kan geven over de voormalige nederzetting(en). De studie beveelt aan deze resten te beschermen zodat verdere degradatie van de archeologische waarden wordt tegengegaan

When Madagascar produced natural rubber: a brief, forgotten yet informative history.

From 1891 to 1914, Madagascar, like other western African countries, was a production zone for forest rubber destined for export to Europe when Asian plantations where not yet sufficiently developed . Numerous species endemic to the forests of the three major Malagasy ecosystems were exploited, often with a view to maximising short term productivity without any consideration for the sustainable management of the resource. This episode represents one of the first cases of industrial exploitation of Madagascar's biological resources. Although Madagascar occupies a modest position on the world rubber market at that time, the exploitation of rubber bore major consequences for the island's forestry resources and, moreover, influenced the vision and discourse of scientists and politicians concerning their management. It was one of the factors triggering awareness of the value of Madagascar's biodiversity and the threat to which it might be exposed through poorly-controlled human activity. As a result, highly repressive and forcible legislation was introduced aimed at containing the activity practiced by local populations considered to be mostly to blame. But from the early days of French colonial rule, naturalists judged the outcomes of political decisions too weak to offer any guarantee of an effective defence. They responded by adopting an intentionally alarmist and catastrophist discourse with the object of provoking a reaction from the politicians, considered too lax. This discourse, in fact, took an about-turn from 1942-45 when the war effort led to a revitalisation of the Malagasy rubber sector as Asian production was mainly out of reach. A second consequence came in 1927 with the creation of a network of protected areas managed by naturalists, making Madagascar at that time, a pioneer in Africa. There was a simultaneous flurry of activity to promote the domestication of Malagasy rubber species, combined with the introduction of new species with high potential (Hevea brasiliensis, Castilloa elastica). However, with the emergence of far more profitable Asian rubber, all attempts at cultivation in Madagascar were abandoned when exploitation ceased to be profitable, and thus the Malagasy forests were redeemed. This episode demonstrates how it was in fact economic reality, by condemning an unprofitable sector, that was the real vehicle by which the survival of Malagasy rubber species was secured, and not the naturalists' discourse, nor the creation of protected zones, nor the promulgation of repressive legislations. This case study is of more than purely historical interest, in that it still has currency where, for example, the exploitation of Prunus africana is concerned