Ergodicity of the zigzag process

The zigzag process is a Piecewise Deterministic Markov Process which can be used in a MCMC framework to sample from a given target distribution. We prove the convergence of this process to its target under very weak assumptions, and establish a central limit theorem for empirical averages under stronger assumptions on the decay of the target measure. We use the classical "Meyn-Tweedie" approach. The main difficulty turns out to be the proof that the process can indeed reach all the points in the space, even if we consider the minimal switching rates

Piecing together the problems in diagnosing low-level chromosomal mosaicism

Low-level somatic chromosomal mosaicism, which usually arises from post-zygotic errors, is a known cause of several well defined genetic syndromes and has been implicated in various multifactorial diseases. It is, however, not easy to diagnose, as various physical and technical factors complicate its identification

Quasi One-Dimensional Photonic Crystals as Building Block for Compact Integrated Optical Refractometric Sensors

A quasi one-dimensional photonic crystal has been fabricated and the applicability of this strong grating for optical sensing has been investigated by measuring the transmission spectra as a function of the cladding refractive index. The cladding index was varied a small range. By monitoring the transmitted output power the transmission stop-band was found to shift by 1 nm wavelength for either a cladding refractive index change of 0.05 or a temperature change of 120 K

Quasi 1-dimensional photonic crystals as building block for compact integrated optical sensors

A quasi one-dimensional photonic crystal has been fabricated and the applicability of this kind of structure for optical sensing has been investigated by measuring the transmission spectra as a function of the cladding refractive index. The cladding index was varied using a liquid flow, of which the index was slowly varied over a small range. The shift with cladding index of the steep stop band edge provides a relatively sensitive detection mechanism in an extremely compact device

An introductory study of house spiders (Araneae) in Belgium

More than 800 spiders were collected in 43 houses heated in winter, distributed mainly in the northern part of Belgium. Information required for the collections to be eligible for the project was: address, construction year, type of house, and surroundings. The spiders were qualified as ‘house spiders’ or ‘garden spiders’. Of the 93 species collected, 19 could be defined as house spiders. Pholcus phalangioides was the most common, followed by Eratigena atrica and Steatoda triangulosa. Garden spiders enter the house much more often in houses in a rural environment than in those situated in clusters, and mainly in spring. The spiders are most common in autumn when many of them are breeding. The common house spiders colonize houses shortly after their construction

O princípio da precaução como uma ferramenta estratégica para redesenhar a (sub)política. Compreensão e perspectivas da ciência política de língua francesa.

O princípio da precaução está inserido em um contexto decisional em evolução, marcado por uma incerteza multidimensional com relação às conseqüências ambientais, econômicas, sociais, éticas e políticas das inovações tecnológicas. Na ciência política de língua francesa, o princípio funciona como uma ferramenta estratégica, uma resposta política ao surgimento de um novo fluxo de incerteza social, voltada principalmente para as inseguranças do mundo científico. Neste trabalho, afirmamos que o princípio da precaução redefine a forma de gerir a incerteza científica, em uma sociedade caracterizada pela indefinição das fronteiras entre atores políticos e subpolíticos. Em sua aplicação, há uma linha de ruptura que reduz a margem de manobra decisória de determinadas entidades subpolíticas, enquanto incentiva outras a agirem. Contudo, enfatizamos que, em um mundo cada vez mais globalizado e interligado, os efeitos da aplicação do princípio da precaução são temporários e locais. Ainda assim, o princípio pode contribuir para os importantes debates a serem desenvolvidos em espaços institucionais, para uma ação reflexiva antecipatória e de apoio à decisão

Fluid forces exerted on slender cylinders in a flow

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Jules Horowitz Reactor Operation Plan 2040 – JHOP2040

JHOP2040 project will deliver a European level strategy addressing resourcing, financing and organisational factors for the most effective way of utilising the Euratom access rights to the forthcoming Jules Horowitz Material Test Reactor (JHR). JHOP2040 is being carried out by a consortium gathering ten partners representing the European partners involved in building the JHR. The project includes an International Scientific Advisory Group and Support Group consisting of external experts in research facility operations, non-European JHR consortium members as well as representatives from Euratom members states, which are not partners in the JHR consortium

Conformational and thermodynamic changes of the repressor/DNA operator complex upon monomerization shed new light on regulation mechanisms of bacterial resistance against β-lactam antibiotics

In absence of β-lactam antibiotics, BlaI and MecI homodimeric repressors negatively control the expression of genes involved in β-lactam resistance in Bacillus licheniformis and in Staphylococcus aureus. Subsequently to β-lactam presence, BlaI/MecI is inactivated by a single-point proteolysis that separates its N-terminal DNA-binding domain to its C-terminal domain responsible for its dimerization. Concomitantly to this proteolysis, the truncated repressor acquires a low affinity for its DNA target that explains the expression of the structural gene for resistance. To understand the loss of the high DNA affinity of the truncated repressor, we have determined the different dissociation constants of the system and solved the solution structure of the B. licheniformis monomeric repressor complexed to the semi-operating sequence OP1 of blaP (1/2OP1blaP) by using a de novo docking approach based on inter-molecular nuclear Overhauser effects and chemical-shift differences measured on each macromolecular partner. Although the N-terminal domain of the repressor is not subject to internal structural rearrangements upon DNA binding, the molecules adopt a tertiary conformation different from the crystallographic operator–repressor dimer complex, leading to a 30° rotation of the monomer with respect to a central axis extended across the DNA