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See detailStudy of the Bacillus subtilis PBP4* and RacX, YlmE racemases in relation with disassembly of biofilms
Vanden Broeck, Arnaud ULg

Conference (2014, April 01)

Bacillus subtilis is a PGPR (Plant Growth Promoting Rhizobacterium) Gram positive bacterium and a model for studying the in vitro formation or disruption of biofilms. At the liquid/air interface of ... [more ▼]

Bacillus subtilis is a PGPR (Plant Growth Promoting Rhizobacterium) Gram positive bacterium and a model for studying the in vitro formation or disruption of biofilms. At the liquid/air interface of standing cultures, B. subtilis forms thick pellicles of limited lifetimes. Some D-amino acids have been reported among the factors playing a role in the disassembly of B. subtilis biofilms and ylmE or racX mutants (in which the racemases YlmE or RacX are absent) show a delay in pellicle disruption. The racX encoding gene is part of a bicistronic operon in which the second gene (pbpE) codes for a Penicillin-Binding Protein, the PBP4* whose function is not characterized in Bacillus. Our studies aim to produce, purify and characterize the role of the PBP4* and RacX, YlmE racemases in relation with the disassembly of biofilms. Biochemical and structural data have been obtained and the role of the three proteins has been partly solved. X-ray structures will permit us to create inhibitor molecules against Bacillus subtilis biofilm formation or disassembly. [less ▲]

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See detailComportements à risque et maladies cardio-vasculaires. Comment infléchir le cours des choses?
Etienne, Anne-Marie ULg; Krzesinski, Jean-Marie ULg; André, Jean-François

Scientific conference (2014, April 01)

«Comportements à risques et maladies cardio-vasculaires, comment infléchir le cours des choses ?» Entre recommandations, croyances et attitudes des médecins, croyances, attitudes et vécu des patients ... [more ▼]

«Comportements à risques et maladies cardio-vasculaires, comment infléchir le cours des choses ?» Entre recommandations, croyances et attitudes des médecins, croyances, attitudes et vécu des patients, comment améliorer la prévention dans le domaine cardio-vasculaire ? [less ▲]

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See detailConceptual metaphors as a tool for the efficient teaching of Dutch and German posture verbs
De Knop, Sabine; Perrez, Julien ULg

in Review of Cognitive Linguistics (2014), 12(1), 1-29

The article deals with the typological differences between the Romance lan- guage French and the Germanic languages German and Dutch for the linguistic expressions of posture and location. It describes ... [more ▼]

The article deals with the typological differences between the Romance lan- guage French and the Germanic languages German and Dutch for the linguistic expressions of posture and location. It describes how these typological differ- ences can be problematic for French-speaking learners of German and Dutch. The main difference between both types of languages is that posture and loca- tion tend to be encoded by posture verbs in Germanic languages and by very general verbs in Romance languages (Talmy 2000). After a detailed description of the semantic networks of the German and Dutch posture verbs, the paper takes a critical look at how these expressions are dealt with in teaching manuals. It further presents strategies for the efficient teaching of posture verbs to foreign language learners. These strategies are among others awareness-raising exercis- es about the compulsory use of posture verbs in Germanic languages and the description of conceptual metaphors in different languages. These pedagogical avenues for the efficient teaching of the Dutch and German posture verbs con- stitute a first step towards the elaboration of an experimental set-up aiming at verifying them. [less ▲]

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See detailComportements à risques et maladies cardio-vasculaires, comment infléchir le cours des choses?
Krzesinski, Jean-Marie ULg; andre, Jean-François

Conference (2014, April 01)

Entre recommandations, croyances et attitudes des médecins, croyances, attitudes et vécu des patients, comment améliorer la prévention dans le domaine cardio-vasculaire?

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See detailValoriser un corpus secondaire : le cas des jeux en histoire
Saal, Caroline ULg

Scientific conference (2014, April 01)

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See detailDétermination de la broyabilité des plaquettes et des pellets de bois
Temmerman, Michaël ULg

Doctoral thesis (2014)

The literature about energy requirements for product milling in mining industry shows the subject has been, and still is, considered by numerous authors. Several milling theories have been proposed for ... [more ▼]

The literature about energy requirements for product milling in mining industry shows the subject has been, and still is, considered by numerous authors. Several milling theories have been proposed for these industries, especially concerning ores milling. Biomass milling, prior to its use as biofuel, has been, by far, less studied. Nevertheless, few measurements are available about energy needed for milling of particular biomass, in particular systems. But studies taking into account enough characteristic of the milled material (origin, moisture content, particle size distribution) are scarce. Moreover, the methods used to measure these properties are generally different. In consequence, nearly none biomass milling model has been proposed. Concerning wood densified product (pellets & briquettes) apparently no data are available yet. . This study draws upon the milling theories developed for the ore processing industry (Von Rittinger, Kick and Bond theories which have been merged by Charles and Hukki) in order to define a method for characterizing wood chip and pellet energy consumption during milling. Thus it proposes parameters and measurement methods that have to be taken into account when milling modelling comes to an end for biomass or densified biomass Energy consumption during wood milling depends on three main factors: the material moisture content, the particle size difference between the feed and the milled product, and the material itself. The latter may be characterized by a single grindability parameter based on an adaptation of Von Rittinger’s constant. A relation characterizing wood pellet energy consumption as a function of the particle size distribution of the pellet ingredients and the milled pellets is proposed as well. This is characteristic of each type of pellet for each moisture content value considered [less ▲]

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See detailÀ la (re)découverte du temple d’Isis à Pompéi
Veymiers, Richard ULg

Scientific conference (2014, April 01)

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See detailIntegration of near-surface geophysical, geological and hydrogeological data with multiple-point geostatistics in alluvial aquifers
Hermans, Thomas ULg

Doctoral thesis (2014)

Alluvial plains constitute essential geological bodies for environmental studies such as contaminated sites remediation, low-enthalpy geothermal energy or groundwater resources. The heterogeneity of these ... [more ▼]

Alluvial plains constitute essential geological bodies for environmental studies such as contaminated sites remediation, low-enthalpy geothermal energy or groundwater resources. The heterogeneity of these deposits governs flow processes and needs to be quantified. A proper description of such complex deposits requires an integrated approach combining geological, geophysical and hydrogeological data. Solving such spatial inverse problems in the Earth Sciences remains a considerable challenge given the large number of parameters to invert for, the non-linearity of forward models and, as a result, the ill-posedness of the problem. Geostatistics is therefore needed to specify prior models, more particularly, information to control the spatial features of the inverse solutions. Two-point geostatistical approaches have been developed to describe the heterogeneity of one geological formation but fail to reproduce the heterogeneity of fluvial deposits with multiple facies. Multiple-point statistics (MPS) introduced the training image (TI) concept to replace the variogram within an extended sequential simulation framework. The use of geophysics to constrain such simulations has been studied in the petroleum industry with wave-based methods (seismic reflection), but little research has been done to assess the use of near-surface potential methods to condition MPS in environmental studies. In this work, we propose to integrate geological (borehole logs), geophysical (electrical resistivity tomography (ERT) profiles) and hydrogeological (hydraulic heads) data within MPS models on the alluvial plain of the Meuse River, Belgium. Potential-based geophysical methods being integrative, they suffer from a relatively poor resolution. We first study how we can improve the informative content of geophysical inversion by including prior information in the ERT inverse problem. Three methods are tested and compared in several field cases, namely the reference model inversion, the structural inversion and the regularized geostatistical inversion. If every method has advantages and drawbacks, the best suited method for the considered problem is the regularized geostatistical method. Electromagnetic borehole logs enable to derive the vertical correlation length of electrical resistivity in the deposits and to subsequently use it to constrain the inversion. In addition to the knowledge of the bedrock position, it enables to retrieve an electrical resistivity distribution of the deposits close to direct observations. This ensures that geophysical models will be informative to constrain MPS simulations. Given the lack of geological and sedimentological data to build accurate TIs, a data base of TIs is built using several different parameters and scenarios. They are all based on a three facies description: clay/loam, sand and gravel corresponding to low, intermediate and high hydraulic conductivity. Then, we develop a methodology to verify the consistency of independently-built TIs with geophysical data. Our methodology starts by creating subsurface models with each TI. From these models we create synthetic geophysical data and from this synthetic data, synthetic inverted models. These models are now compared with a single inverted model obtained from the field survey, allowing for our definition of what is ``consistent''. To that extent, we calculate the Euclidean distance between any two inverted models as well as field data and visualize the results in a 2D or 3D space using multidimensional scaling (MDS). With this technique, it is possible to verify if field cases fall in the distribution represented by synthetic cases, and thus are consistent with them. In a second step, we present a cluster analysis on the MDS-map to highlight which parameters are the most sensitive for the construction of TI. Based on this analysis, a probability of each geological scenario is computed through kernel smoothing of the densities in reduced projected metric space. The integration of hydrogeological data is made through a stochastic inversion method: the probability perturbation method (PPM), using MPS constrained with geophysical data to generate models. The PPM algorithm automatically seeks solutions fitting both hydrogeological data and training-image based geostatistical constraints. Only geometrical features of the model are affected by the perturbation, i.e. we do not attempt to directly find the optimal value of hydrogeological parameters (chosen a priori), but the optimal spatial distribution of facies whose prior distribution is quantified in a training image. Tracing experiments may be used to further constrain hydrogeological models. ERT has proven its ability to monitor salt tracer tests, but few studies have investigated its performances in thermal tracing experiments. In this study, we demonstrate the ability of surface and crosshole ERT to image quantitatively temperature changes during heat injection experiments. Such resistivity data provides important information to improve hydrogeological models. Our study proves that ERT, especially crosshole ERT, is a reliable tool to follow thermal tracing experiments. It also confirms that ERT should be included to in situ techniques to characterize heat transfer in the subsurface and to monitor geothermal resources exploitation. [less ▲]

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See detailNeuropathies proximales du membre supérieur
WANG, François-Charles ULg

Conference (2014, April 01)

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See detailPrise de risque et zéro-mort
Dumoulin, André ULg

Scientific conference (2014, April 01)

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See detailSoil organic carbon assessment by field and airborne spectrometry in bare croplands: accounting for soil surface roughness
Denis, Antoine ULg; Stevens, Antoine; Van Wesemael, Bas et al

in Geoderma (2014), 226-227(August 2014), 94102

Visible, Near and Short Wave Infrared (VNSWIR) diffuse reflectance spectroscopy (350 nm to 2500 nm) has been proven to be an efficient tool to determine the Soil Organic Carbon (SOC) content. SOC ... [more ▼]

Visible, Near and Short Wave Infrared (VNSWIR) diffuse reflectance spectroscopy (350 nm to 2500 nm) has been proven to be an efficient tool to determine the Soil Organic Carbon (SOC) content. SOC assessment (SOCa) is usually done by using calibration samples and multivariate models. However one of the major constraints of this technique, when used in field conditions is the spatial variation in surface soil properties (soil water content, roughness, vegetation residue) which induces a spectral variability not directly related to SOC and hence reduces the SOCa accuracy. This study focuses on the impact of soil roughness on SOCa by outdoor VIS-NIR-SWIR spectroscopy and is based on the assumption that soil roughness effect can be approximated by its related shadowing effect. A new method for identifying and correcting the effect of soil shadow on reflectance spectra measured with an Analytical Spectral Devices (ASD) spectroradiometer and an Airborne Hyperspectral Sensor (AHS-160) on freshly tilled fields in the Grand Duchy of Luxembourg was elaborated and tested. This method is based on the shooting of soil vertical photographs in the visible spectrum and the derivation of a shadow correction factor resulting from the comparison of “reflectance” of shadowed and illuminated soil areas. Moreover, the study of laboratory ASD reflectance of shadowed soil samples showed that the influence of shadow on reflectance varies according to wavelength. Consequently a correction factor in the entire [350–2500 nm] spectral range was computed to translate this differential influence. Our results showed that SOCa was improved by 27% for field spectral data and by 25% for airborne spectral data by correcting the effect of soil relative shadow. However, compared to simple mathematical treatment of the spectra (first derivative, etc.) able to remove variation in soil albedo due to roughness, the proposed method, leads only to slightly more accurate SOCa. [less ▲]

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See detailEpoch-dependent absorption line profile variability in lambda Cep
Uuh-Sonda, J. M.; Rauw, Grégor ULg; Eenens, P. et al

in Revista Mexicana de Astronomia y Astrofisica (2014), 50

We present the analysis of a multi-epoch spectroscopic monitoring campaign of the O6 Ief star lambda Cep. Previous observations reported the existence of two modes of non-radial pulsations in this star ... [more ▼]

We present the analysis of a multi-epoch spectroscopic monitoring campaign of the O6 Ief star lambda Cep. Previous observations reported the existence of two modes of non-radial pulsations in this star. Our data reveal a much more complex situation. The frequency content of the power spectrum considerably changes from one epoch to the other. We find no stable frequency that can unambiguously be attributed to pulsations. The epoch-dependence of the frequencies and variability patterns are similar to what is seen in the wind emission lines of this and other Oef stars, suggesting that both phenomena likely have the same, currently still unknown, origin. [less ▲]

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See detailHaplotype information combined with iterative pruning PCA (ipPCA) to improve population clustering
Chaichoompu, Kridsadakorn ULg; Fouladi, Ramouna; Wangkumhang, Pongsakorn et al

Scientific conference (2014, April 01)

Single Nucleotide Polymorphisms (SNPs) are commonly used to capture variations between populations. Often genome-wide SNP data are pruned based on linkage disequilibrium (LD) patterns or small subsets of ... [more ▼]

Single Nucleotide Polymorphisms (SNPs) are commonly used to capture variations between populations. Often genome-wide SNP data are pruned based on linkage disequilibrium (LD) patterns or small subsets of SNPs are selected (e.g. PCA-correlated SNPs) to reproduce the genomic structure of the complete data set. Identifying and differentiating between subpopulations using such a reduced set can become challenging, especially when similar geographic regions are involved or when spurious patterns are likely to exist. Although PCA-based methods can resolve structure, they cannot infer ancestry. On the other hand, the structure of haplotypes in unrelated individuals can reveal useful information about genetic ancestry. Notably, haplotype composition and the pattern of LD between markers may vary between larger populations but may also play a role within more confined geographic regions. In addition, iterative pruning principal component analysis (ipPCA) has been shown to be a powerful tool to cluster subpopulations based on SNP profiles. Despite the complexities that are associated with haplotype inference, we argue that added value can be obtained when the LD structure between SNPs is exploited in the search for relevant population strata. In this work, we propose to combine an LD-based novel haplotype encoding scheme with the ipPCA machinery to retrieve fine population substructures. The approach is compared to state-of-the-art methods in the context of population substructure and admixture analysis. [less ▲]

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See detailMetabolically healthy overweight and obesity
Esser, Nathalie ULg; SCHEEN, André ULg; PAQUOT, Nicolas ULg

in Annals of Internal Medicine (2014), 160(7), 514

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See detailMolecular evidence of Anaplasma phagocytophilum in wild boar (Sus scrofa) in Belgium
Nahayo, Adrien; Bardiau, Marjorie ULg; Volpe, Rosario ULg et al

in BMC Veterinary Research (2014), 10(80),

Anaplasma phagocytophilum is a tick-borne pathogen of veterinary and human importance. Both ticks as vectors and vertebrates as reservoir hosts are essential for the cycle maintenance of this bacterium ... [more ▼]

Anaplasma phagocytophilum is a tick-borne pathogen of veterinary and human importance. Both ticks as vectors and vertebrates as reservoir hosts are essential for the cycle maintenance of this bacterium. Currently, the whole range of animal species reservoirs for A. phagocytophilum in natural environment is still unknown. Therefore, the aim of this study was to estimate the prevalence of infection with A. phagocytophilum in the wild boar population in southern Belgium. [less ▲]

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See detail“Fairebel” fair milk: a multi-level innovation
Feyereisen, Marlène ULg; Melard, François ULg

Conference (2014, April)

The research focuses on the case study of the Belgian fair-trade milk “Fairebel”, which was created by dairy farmers a few months after the 2009 European milk crisis. This innovation is overseen by the ... [more ▼]

The research focuses on the case study of the Belgian fair-trade milk “Fairebel”, which was created by dairy farmers a few months after the 2009 European milk crisis. This innovation is overseen by the “Fair Milk” programme set up by the European Milk Board (EMB), a European organization of dairy farmers, which has established five fair-trade milk labels in European countries (Austria, the Netherlands, Belgium, Luxembourg, and France). At the Belgian level, the case study of the “Fairebel” project shows how the dairy system is institutionally, politically, and technically locked in. In such an irreversible system, the developers of “Fairebel” have had to use cunning and espouse some contradictions (even inconsistencies) in order to build their idea of fair-trade milk and to achieve its commercialization in the real world of commodities. Also, the “Fairebel” project is trying to increase the market power of dairy farmers and by-passes entirely the dairy industry in Belgium, which refused to support the project. For example, the developers of “Fairebel” stock up on the spot market and the Fairebel” milk cartons are produced and filled by the Luxembourg co-operative dairy Luxlait. On this level, the “Fairebel” project is more a “reorientation of trajectories” than a radical transition of the system: It uses internal resources of the main system to try to change some of its detrimental consequences, such as the prices paid to dairy farmers, without forcing through associated structural transitions. On the European level of the EMB, in which “Fairebel” participates, the transition of the system is radicalized by changing the character and the structure of the regime itself (e.g. CAP): reversal of the balance of power between dairy farmers and dairy processors, re-appropriation of the means of production by the farmers, and modification of the economic and trade rules of the dairy products (e.g., monitoring agency). Taken together, these two levels of this fair-milk innovation strengthen each other, so that the transition that “Fairebel” has inspired is more radical than it would seem when the Belgian level is considered alone. [less ▲]

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