Renormings of Lp(Lq)L^p(L^q)

We investigate the best order of smoothness of $L^p(L^q)$. We prove in particular that there exists a $C^\infty$-smooth bump function on $L^p(L^q)$ if and only if $p$ and $q$ are both even integers and $p$ is a multiple of $q$.Comment: 18 pages; AMS-Te

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.

Adjuvant formulation for veterinary vaccines: Montanide™ Gel safety profile

AbstractSelecting the adjuvant is one of the key for the success of the vaccine in the field. Selecting a flexible adjuvant that will fit with several vaccines dedicated to one or more animal species is a source of economical efficiency. Frequently the safety or efficacy obtained with one model is different from another: there are few adjuvants fitting with the expectation of more than one animal species. Montanide™ Gel an innovative polymeric adjuvant have been tested in several animals. Our studies demonstrated the ability to use this adjuvant in dogs, cattle and pig vaccines. Three trials were performed to validate Montanide™ Gel ability to be used in cattle, pigs and dogs. Respectively, vaccines were formulated with ovalbumin in cattle, Pasteurella Multocida anatoxin and Bordetella bronchiseptica cell walls for pig and finally with parvovirus associated to two leptospira valence for dog model. All antigenic media used in the three trials were inactivated. In all trial, safety was followed through behaviour and temperature measurement as well as histology studies.Montanide™ Gel adjuvant can be used associated with a wide range of antigenic media. Nevertheless, the uses of such adjuvant need validation in avian and fish vaccines

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

A simple variance estimator of change for rotating repeated surveys: an application to the EU-SILC household surveys

A common problem is to compare two cross-sectional estimates for the same study variable taken on two different waves or occasions, and to judge whether the change observed is statistically significant. This involves the estimation of the sampling variance of the estimator of change. The estimation of this variance would be relatively straightforward if cross-sectional estimates were based on the same sample. Unfortunately, samples are not completely overlapping, because of rotations used in repeated surveys. We propose a simple approach based on a multivariate (general) linear regression model. The variance estimator proposed is not a model-based estimator. We show that the estimator proposed is design consistent when the sampling fractions are negligible. It can accommodate stratified and two-stage sampling designs. The main advantage of the approach proposed is its simplicity and flexibility. It can be applied to a wide class of sampling designs and can be implemented with standard statistical regression techniques. Because of its flexibility, the approach proposed is well suited for the estimation of variance for the European Union Statistics on Income and Living Conditions surveys. It allows us to use a common approach for variance estimation for the different types of design. The approach proposed is a useful tool, because it involves only modelling skills and requires limited knowledge of survey sampling theory

Compositionality, stochasticity and cooperativity in dynamic models of gene regulation

We present an approach for constructing dynamic models for the simulation of gene regulatory networks from simple computational elements. Each element is called a ``gene gate'' and defines an input/output-relationship corresponding to the binding and production of transcription factors. The proposed reaction kinetics of the gene gates can be mapped onto stochastic processes and the standard ode-description. While the ode-approach requires fixing the system's topology before its correct implementation, expressing them in stochastic pi-calculus leads to a fully compositional scheme: network elements become autonomous and only the input/output relationships fix their wiring. The modularity of our approach allows to pass easily from a basic first-level description to refined models which capture more details of the biological system. As an illustrative application we present the stochastic repressilator, an artificial cellular clock, which oscillates readily without any cooperative effects.Comment: 15 pages, 8 figures. Accepted by the HFSP journal (13/09/07

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

Adaptive mesh refinement with spectral accuracy for magnetohydrodynamics in two space dimensions

We examine the effect of accuracy of high-order spectral element methods, with or without adaptive mesh refinement (AMR), in the context of a classical configuration of magnetic reconnection in two space dimensions, the so-called Orszag-Tang vortex made up of a magnetic X-point centered on a stagnation point of the velocity. A recently developed spectral-element adaptive refinement incompressible magnetohydrodynamic (MHD) code is applied to simulate this problem. The MHD solver is explicit, and uses the Elsasser formulation on high-order elements. It automatically takes advantage of the adaptive grid mechanics that have been described elsewhere in the fluid context [Rosenberg, Fournier, Fischer, Pouquet, J. Comp. Phys. 215, 59-80 (2006)]; the code allows both statically refined and dynamically refined grids. Tests of the algorithm using analytic solutions are described, and comparisons of the Orszag-Tang solutions with pseudo-spectral computations are performed. We demonstrate for moderate Reynolds numbers that the algorithms using both static and refined grids reproduce the pseudo--spectral solutions quite well. We show that low-order truncation--even with a comparable number of global degrees of freedom--fails to correctly model some strong (sup--norm) quantities in this problem, even though it satisfies adequately the weak (integrated) balance diagnostics.Comment: 19 pages, 10 figures, 1 table. Submitted to New Journal of Physic

Structural pathway of regulated substrate transfer and threading through an Hsp100 disaggregase

Refolding aggregated proteins is essential in combating cellular proteotoxic stress. Together with Hsp70, Hsp100 chaperones, including Escherichia coli ClpB, form a powerful disaggregation machine that threads aggregated polypeptides through the central pore of tandem adenosine triphosphatase (ATPase) rings. To visualize protein disaggregation, we determined cryo–electron microscopy structures of inactive and substrate-bound ClpB in the presence of adenosine 5′-O-(3-thiotriphosphate), revealing closed AAA+ rings with a pronounced seam. In the substrate-free state, a marked gradient of resolution, likely corresponding to mobility, spans across the AAA+ rings with a dynamic hotspot at the seam. On the seam side, the coiled-coil regulatory domains are locked in a horizontal, inactive orientation. On the opposite side, the regulatory domains are accessible for Hsp70 binding, substrate targeting, and activation. In the presence of the model substrate casein, the polypeptide threads through the entire pore channel and increased nucleotide occupancy correlates with higher ATPase activity. Substrate-induced domain displacements indicate a pathway of regulated substrate transfer from Hsp70 to the ClpB pore, inside which a spiral of loops contacts the substrate. The seam pore loops undergo marked displacements, along with ordering of the regulatory domains. These asymmetric movements suggest a mechanism for ATPase activation and substrate threading during disaggregation