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See detailLe développement de l’agriculture familiale par les transferts des migrants
Yao Namé, Juste Michel ULg; Lebailly, Philippe ULg

Conference (2016, September 25)

The following pages report the results of our survey conducted among (Malian, Senegalese and Mauritanian) Soninké migrants during the period of 14th to 4 December 2015, living in the social residences of ... [more ▼]

The following pages report the results of our survey conducted among (Malian, Senegalese and Mauritanian) Soninké migrants during the period of 14th to 4 December 2015, living in the social residences of the former home Pinel (first home of migrant workers in France). This survey had to aim to discuss the implementation and use of a new tool to transfer the money in order to reduce use of informal channels, to promote financial inclusion, to finance smallholding and to develop entrepreneurship in rural by granting of credits medium or long term via Microfinance Institutions (IMF). [less ▲]

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See detailHydrodynamics and bed stability at smooth-to-rough transitions. Experiments based on acoustic flow measurements
Duma, Diana ULg

Doctoral thesis (2016)

As reflected in the scale of large contemporary hydropower schemes, flowing water may carry huge amounts of energy. If not mastered properly, this energy may cause impressive channel erosion and local ... [more ▼]

As reflected in the scale of large contemporary hydropower schemes, flowing water may carry huge amounts of energy. If not mastered properly, this energy may cause impressive channel erosion and local scour. Therefore, one lasting concern in hydraulic engineering has been the stability of structures, riverbeds and riverbanks against flow erosion. Two main limitations of current understanding of riverbed and riverbank stability are highlighted: the first one is directly linked to the evaluation of the flow action, while the second one relates to the conceptual framework in which stone stability is evaluated. Since the standard approaches use the mean bed shear stress to quantify the flow forces, they may only apply under uniform flow conditions, for which the ratio of turbulence intensity to the bed shear stress remains almost constant and the influence of turbulence is therefore implicitly incorporated. For non-uniform flow, correction factors have been conventionally applied to account for the turbulence fluctuations; but this approach does not reproduce the physical influence of turbulence higher in the water column and can only be used as a rule of thumb. A new approach was initiated recently in literature. Instead of using the standard Shields parameter, it quantifies the flow forces by means of a new set of parameters which combine explicitly the velocity and turbulence distributions over a certain water depth above the riverbed, while remaining reasonably accessible for engineering applications. Next, this quantity is related to a mobility parameter, which describes the bed damage. This new approach requires additional high quality experimental data to confirm its validity for a wider range of non-uniform flow. In this research, the focus was set on a single canonical configuration, namely a smooth-to-rough transition. We take a preventive perspective by focusing on the flow and bed stability conditions before a scour hole starts to develop and we are interested in characterising the flow conditions to ensure bed stability, i.e. prevent the dislodging of bed material downstream of the structure. As a second specific objective of the thesis, we aimed at evaluating the feasibility of using acoustic techniques to properly estimate the new bed stability parameters proposed in literature in the last decade and draw conclusions on stone mobility at smooth-to-rough transitions. The experimental tests were conducted in two laboratory flumes, a horizontal bottom flume (6 m long and 15 cm wide) and a tilting flume (up to 4% slope, 20 m long and 50 cm wide), in which we measured the flow velocity at a 100 Hz frequency, using two different acoustic instruments: an Ultrasound Velocity Profiler (UVP) and a 3D Acoustic Doppler Velocity Profiler (ADVP). The measurements were done immediately downstream of the transition from smooth-to-rough. Two types of tests were undertaken. In the first type, the stones were glued with silicone on the flume bottom and velocity measurements were performed without stone motion. This enables measurements of the flow characteristics both below and above the threshold for inception of sediment motion, without perturbations induced by stone displacements. In the second type, the stones in the measurement area were laid on the bottom of the flume (i.e. not glued) and the number of entrained stones was recorded. The tests were conducted by varying (i) the grain size of the bed material (8 mm, 15 mm and 30 mm), (ii) the flow velocity (between 0.74 m/s and 1.16 m/s), (iii) the sediments density (1410 kg/m³, 1690 kg/m³ and 2650 kg/m³) and (iv) the configuration (quasi-uniform vs. smooth-to-rough transition). Indeed, for the purpose of comparison, a uniform rough bed (quasi-uniform configuration) was considered also, by replacing the smooth part of the bed with similar sediments as in the measurement area. After a specific signal processing, flow variables were derived from the measurements and were next exploited to evaluate several bed stability parameters, with the aim of correlating them with bed damage data obtained from dedicated experiments. The results showed no correlation between the bed damage and the bed shear stress or between the bed damage and flow turbulent kinetic energy. In contrast, when the flow action is described by both mean velocity and turbulence characteristics, a relative good correlation with the bed damage was observed. Nonetheless, these correlations appear only per subset of points corresponding to the same grain size and/or same material density or flume geometry. With a total of 45 hydraulic configurations for which the flow characteristics were measured and 66 (times four repetitions) tests in which the bed damage was observed, the present research ends up with a unique dataset, which may prove useful in various research such as for the validation of 2D-vertical and 3D turbulent flow and morphodynamic simulations. Another key outcome of the present doctoral research is a systematic comparison between measurements conducted with the UVP and the ADVP. The ADVP is deemed generally more accurate and reliable. Nonetheless, both instruments remain somehow complementary. We showed that, under certain conditions, the considered instruments have the potential to contribute to the assessment of bed stability in the considered configurations. [less ▲]

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See detailApplications des relevés 3D au patrimoine, de l'acquisition au système d'information 3D
Hallot, Pierre ULg; Billen, Roland ULg; Poux, Florent ULg et al

Conference (2016, September 23)

Les techniques permettant l’acquisition 3D du patrimoine bâti sont maintenant assez mures et démocratiques pour être utilisées à grande échelle. De plus en plus d’édifices font l’objet d’une sauvegarde ... [more ▼]

Les techniques permettant l’acquisition 3D du patrimoine bâti sont maintenant assez mures et démocratiques pour être utilisées à grande échelle. De plus en plus d’édifices font l’objet d’une sauvegarde numérique sous la forme de nuages de points colorés. Il reste néanmoins de nombreux défis à relever notamment pour : harmoniser les pratiques d’acquisition en terme de qualité et de précision, assurer l’interopérabilité entre les jeux de données ; exploiter pleinement l’information ponctuelle collectée ; et proposer une visualisation adéquate de ces grands jeux de données. Dans le cadre des développements réalisés à l’Unité de Géomatique de l’ULg, nous travaillons à la mise au point de systèmes d’informations permettant d’assurer un lien entre les informations sémantiques issues des applications archéologiques, architecturales, d’histoire de l’art avec les modèles 3D réalisés. La mise en place de ces systèmes d’informations passe par plusieurs étapes de recherche relatives à la sectorisation automatique, les structures de données, la définitions d’ontologies thématiques et finalement les règles sémiologiques de représentations dans un environnement virtuel 3D. Au cours de cette présentation, nous proposons de parcourir trois projets de recherche en cours au sein de l’Unité afin l’illustrer nos propos. Nous présenterons plus particulièrement le cas de la cathédrale Saint-Paul de Liège. [less ▲]

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See detailAnalyse comparative des coûts de production rizicole dans les pays de la Communauté Economique des Pays des Grands Lacs (CEPGL).
Furaha Mirindi, Germaine ULg; Lebailly, Philippe ULg

Conference (2016, September 23)

Cet article fait une analyse comparative des résultats économiques de la production rizicole durant la saison B 2014 dans les trois pays de la CEPGL qui sont la République Démocratique du Congo, le Rwanda ... [more ▼]

Cet article fait une analyse comparative des résultats économiques de la production rizicole durant la saison B 2014 dans les trois pays de la CEPGL qui sont la République Démocratique du Congo, le Rwanda et le Burundi. L’approche comparative permet de trouver les explications des différences des résultats en partie dans les politiques mises en œuvre dans chaque pays. Les enquêtes ont été menées dans la plaine de la Ruzizi partagée entre les trois pays auprès de 240 producteurs du riz choisi à partir de la méthode des quotas sur la base d'une stratification des exploitations rizicoles. Dans le site congolais (où il est plus difficile d’accéder aux intrants et crédits), les coûts de production d’1kg de paddy sont les plus élevés avec une fonction de production y=0,034x+0,053z+0,422 et le rendement le plus bas (2698kgs). Par contre, dans les sites burundais et rwandais où l’Etat intervient dans l’approvisionnement en intrants et particulièrement dans le site rwandais, l’accès aux crédits, les fonctions de production sont respectivement de y=0,024x+0,031z+0,297 et y=0,017x+0,023z+0,269 avec des rendements de 3962kgs et 5339kgs dans le même ordre. Les coûts de production supportés sur un hectare rizicole ou encore pour la production d’une tonne de paddy varient selon le pays car ils dépendent de la valeur des intrants utilisés et des autres charges de structures. Ils varient ainsi de 1139,4USD à 1354,5USD/ ha et de 269 à 422USD/tonne. [less ▲]

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See detailLes nouvelles technologies au servivce du patient diabétique
RADERMECKER, Régis ULg

Conference given outside the academic context (2016)

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See detailSupprimer la Communauté française ? Quelles perspectives pour le paysage institutionnel francophone ?
Behrendt, Christian ULg

Conference given outside the academic context (2016)

Conférence donnée à l'invitation de l'Union des entreprises à profit social (UNIPSO), à Bruxelles, Centre "Le Botanique", le 23 septembre 2016

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See detailUn morso di più: ecologia del cannibalismo in Salamandra salamandra
Melotto, Andrea; Manenti, Raoul; Ficetola, Francesco et al

Conference (2016, September 23)

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See detailDevelopment of alternative methods to control aphids (Hemiptera: Aphididae): from wheat-pea intercropping to the use of semiochemical dispensers
Chevalier Mendes Lopes, Thomas ULg

Doctoral thesis (2016)

Increasing the sustainability of food production is a major challenge in today’s agriculture. Several practices can be implemented to reduce the use of external inputs such as agrochemicals. In terms of ... [more ▼]

Increasing the sustainability of food production is a major challenge in today’s agriculture. Several practices can be implemented to reduce the use of external inputs such as agrochemicals. In terms of insect pest control, the concept of integrated pest management (IPM) has been exploited to minimize the application of chemical insecticides. The idea is to limit pest infestations while promoting their control by natural enemies. One possibility is to increase within crops plant diversity namely by intercropping. Semiochemical dispensers may also be used to attracted natural enemies into crops. Focusing on wheat (Triticum aestivum Linnaeus), several types of intercropping can be practiced with variable effects on pests and natural enemies. This PhD thesis focuses on the potential of wheat-pea (Pisum sativum Linnaeus) intercropping as a way to reduce aphid (Hemiptera: Aphididae) infestations. We firstly assessed the diversity of aphid and their parasitoid species in wheat and pea fields using yellow pan traps and in situ observations on plants. Whether several aphid species were trapped, only Sitobion avenae (Fabricius), Metopolophium dirhodum (Walker), Rhopalosiphum padi (Linnaeus) and Acyrthosiphon pisum (Harris) were found on wheat tillers and pea plants respectively. Regarding parasitoids, some species can use wheat and/or pea aphids as hosts. The first Belgian parasitoid species checklist was established, with the inclusion of four Aphidiinae (Hymenoptera: Braconidae) and three Aphelinus (Hymenoptera: Aphelinidae) species as new records. In terms of abundance, we firstly compared the effect of two types of wheat-pea intercropping (mixed and alternate strip cropping) on aphids and their natural enemies with pure stands of both crops. The mixture was particularly efficient to reduce pea aphid populations, while alternate strips were more suitable for the control of wheat aphids. However, natural enemies were more abundant in the pure stands, showing that additional methods may be needed to attract them more efficiently. One possibility is the use of semiochemicals dispensers. In another field study, we combined a wheat-pea mixture with methyl salicylate (MeSA) dispensers. This substance was selected due to its known attractive effect towards some aphid beneficials. Even though adult hoverflies (Diptera: Syrphidae) were not particularly attracted by the mixture combined with MeSA dispensers, they may have stimulated their oviposition behaviour. Also, mummified aphids were significantly more abundant in the pure stand of pea compared with the mixture (with and without MeSA). However, parasitism rates did not differ significantly between treatments. Beneficial effects of wheat-pea intercropping were clearly demonstrated for aphid control. Other agronomic aspects make this practice particularly interesting in low-input farming systems. These are discussed, along the limitations related to the use semiochemicals in field conditions. Perspectives for further research works are also proposed. [less ▲]

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See detailInfluence d'un programme de revalidation multidisciplinaire post-cancer du sein sur la fonction physique
Leclerc, Anne-France ULg; Foidart-Dessalle, Marguerite ULg; BURY, Thierry ULg et al

in 9ème Congrès commun SFMES - SFTS : Abstract book (2016, September 22)

Objectif : Le cancer du sein ainsi que ses traitements sont à l'origine de nombreux effets secondaires indésirables, notamment sur la fonction physique. Cette étude a pour objectif de déterminer les ... [more ▼]

Objectif : Le cancer du sein ainsi que ses traitements sont à l'origine de nombreux effets secondaires indésirables, notamment sur la fonction physique. Cette étude a pour objectif de déterminer les bénéfices éventuels d’un programme de revalidation multidisciplinaire sur la santé physique des femmes ayant été traitées pour un cancer du sein et d'évaluer l'influence de certaines caractéristiques individuelles initiales sur la réponse du groupe expérimental au programme de revalidation. Matériel et méthodes : L'étude constitue un essai clinique contrôlé non-randomisé évaluant une population totale de 209 patientes, recrutées sur base du volontariat et réparties en deux groupes, soit un groupe contrôle (n = 106) et un groupe expérimental (n = 103). Ce dernier a bénéficié d’une revalidation de trois mois comprenant un entraînement physique supervisé à raison de trois séances par semaine et diverses sessions psycho-éducatives. Pour l'ensemble des participantes, des évaluations constituées d'une part de mesures physiques et fonctionnelles et d'autre part de mesures de composition corporelle ont été programmées à 0 et 3 mois. Celles-ci ont inclus un test de souplesse ("Sit and Reach"), un test d'effort maximal sur bicyclette ergométrique avec suivi cardio-respiratoire, un test de marche de six minutes et la mesure de l'indice de masse corporelle et du pourcentage de graisse corporelle. Afin d'affiner l'analyse, trois groupes ont également été constitués au sein du groupe expérimental à partir des caractéristiques individuelles de thérapie adjuvante (présence de chimiothérapie ou non), de chirurgie (mastectomie ou tumorectomie) et de délai de fin de traitement (délai ≤ 4 mois ou ≥ 8 mois). Résultats : Initialement, toutes les patientes présentent un état de déconditionnement physique, non influencé par le délai de fin de traitement ou par le type de chirurgie, mais bien influencé par la présence d'une chimiothérapie puisque la VO2max apparaît significativement plus faible dans ce cas. Au terme des trois mois, la souplesse (p < 0,0001), la consommation maximale d'oxygène (p < 0,0001), la puissance maximale aérobie (p < 0,0001) et la distance de marche en six minutes (p < 0,0001) s’améliorent significativement au sein du groupe expérimental. Au sein du groupe contrôle, aucune amélioration n'est constatée, excepté pour la distance de marche (p = 0,0031). Par ailleurs, une augmentation significative de l'indice de masse corporelle (p = 0,034) et du pourcentage de graisse corporelle (p = 0,034) est observée au sein du groupe contrôle alors que ce paramètre diminue significativement au sein du groupe expérimental (p = 0,037). Enfin, toutes les patientes du groupe expérimental présentent un même profil de progression quelles que soient leurs caractéristiques individuelles initiales. Conclusion : Cette étude démontre ainsi les effets bénéfiques, tant sur le plan physique que de la composition corporelle, d’une prise en charge multidisciplinaire chez des femmes ayant été traitées pour le cancer du sein. [less ▲]

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See detailGlucose production: influence of the datasets choice on LCA results
Gerbinet, Saïcha ULg; Belboom, Sandra ULg; Léonard, Angélique ULg

Poster (2016, September 22)

The aim of this study is to have a good understanding of the environmental impact of glucose production. Glucose is generally produced from corn or wheat. Since agricultural processes are known to be ... [more ▼]

The aim of this study is to have a good understanding of the environmental impact of glucose production. Glucose is generally produced from corn or wheat. Since agricultural processes are known to be difficult to evaluate by LCA, the results obtained with two different LCA databases, Gabi and EcoInvent, are compared in this work. The production of glucose from raw materials can be divided in two steps: the agricultural step allowing the plant production, and the conversion step including the extraction of the starch from the plant and its hydrolysis into glucose. Preliminary results underline the high impact of the agricultural step, so a special attention has been paid to these data. Specific Belgian data collected by the Walloon Agricultural Research Centre (CRA-W) (2014) [1] have been used as primary data (yield, amount of fertilizers, etc.), either using EcoInvent or Gabi datasets background data to model fertilizers, diesel consumption, etc. A third model was built using only data available in Ecoinvent for corn and wheat cultures. For the conversion step, literature data have been used along with some industrial data. As few studies are available in the literature concerning starch hydrolysis, the focus has been placed on data validation (mass balance checks, cross-reference information, etc.). Based on these multiple sources, it is possible to compare the LCA results for the production of 1 kg of glucose for three different cases, summarized in the following table. Table 1: Summary of modelled cases Agricultural step Conversion steps Primary data Dataset Primary data Dataset Case 1 Belgian GaBi Literature + Industry GaBi Case 2 Belgian Ecoinvent Literature + Industry Ecoinvent Case 2 Ecoinvent Literature + Industry Ecoinvent The results obtained using these three models will be presented, at both the inventory and impact assessment steps. They show significant differences and highlight the need to understand in depth the involved assumptions when developing the datasets, in addition to the ones adopted for the inventory. [less ▲]

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See detailCours No 1: Astrophysique et Techniques Spatiales: Ingés aéro/ Ingés Phys 2016-2017 (Fichier PDF + vidéos: mov)
Surdej, Jean ULg

Learning material (2016)

In this course of Astronomy and space techniques, we introduce all the necessary concepts that enable us to understand basic observational data as well as modern ground-based and space telescopes and ... [more ▼]

In this course of Astronomy and space techniques, we introduce all the necessary concepts that enable us to understand basic observational data as well as modern ground-based and space telescopes and their instrumentation. This course has been designed for future engineers willing to understand and communicate with other people basic concepts of astronomy as well as to those wishing to pursue more specialized studies in astrophysics (cf. end-of-year thesis oriented towards astrophysics, master in space sciences, PhD in astrophysics, ...) or a future career in this field. In the first part of this course, we present the main discoveries in astrophysics already known by the antique greek astronomers, including an introduction to the different spherical coordinate systems and to photometry. [less ▲]

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See detailGAVRAY Claire (2016) The evolution of boys’ and girls’ attitudes and moods at the light of their historical opportunities : the case of violence and depression -
Gavray, Claire ULg

Conference (2016, September 22)

depression mood and violent behaviour are linked as a common dynamic amongst female teenargers but not amongst male ones ( twho different paths for them). The roots of depression and violence are ... [more ▼]

depression mood and violent behaviour are linked as a common dynamic amongst female teenargers but not amongst male ones ( twho different paths for them). The roots of depression and violence are connected to gender socialisation (importance of lack of recognition and negative life events in private sphere for girls and in public sphere for boys). [less ▲]

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See detailPhosphate-based composite electrodes for Li/Na-ion batteries: upscalable solution syntheses with in-situ solid carbon addition
Vertruyen, Bénédicte ULg; Brisbois, Magali; Eshraghi, Nicolas ULg et al

Conference (2016, September 22)

Since the success story of lithium iron phosphate, other phosphate-based compounds have attracted a lot of interest as promising candidates for positive electrodes in lithium-ion or sodium-ion batteries ... [more ▼]

Since the success story of lithium iron phosphate, other phosphate-based compounds have attracted a lot of interest as promising candidates for positive electrodes in lithium-ion or sodium-ion batteries. Their electronic conductivity usually has to be improved through the preparation of composite powders ensuring intimate contact between the active material and conductive carbon. We report on the one-step synthesis of composite precursors using spray-drying or hydrothermal synthesis routes, two techniques which offer easy scaling-up of production. We show that addition of a solid carbon source (carbon black or carbon nanotubes) into the solution has a strong influence on the powder microstructure and is very effective in improving the battery cycling performance, taking our recent results on phosphates [Fex(PO4)(OH)y.zH2O)] and fluorophosphates [Na2FePO4F, Na3V2(PO4)2F3] as examples. We also compare this approach with the addition of the carbon source as a soluble precursor (such as ascorbic acid or citric acid) where the in situ formation of carbon is achieved by a heat treatment in inert atmosphere (typically argon). [less ▲]

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See detailStructure and Dynamics of Ge-Se Liquids and Glasses under Pressure
Yildirim, Can ULg

Doctoral thesis (2016)

Among network forming glasses, chalcogenide glasses are of great importance not only for their optoelectronic applications, but also for the network structure that displays enhanced structural variability ... [more ▼]

Among network forming glasses, chalcogenide glasses are of great importance not only for their optoelectronic applications, but also for the network structure that displays enhanced structural variability due to the covalent bonding network. In this project, we study the Ge-Se binary alloy as the target system in order to investigate the structure and dynamics of the liquid and glassy phases under pressure by using a combination of ab initio molecular dynamics (AIMD) simulations and X-ray scattering experiments. The wide glass forming range of the GexSe100􀀀x system allows one to tune the stiffness of the network structure by increasing the mean coordination number with the Ge content which affects the macroscopic material properties such as resistance to aging, hardness, conductivity, and fragility. In this respect, we study 10 different AIMD generated and 5 experimentally produced (i.e melt quenching) compositions spanning the flexible-to-rigid elastic phase transitions according to Maxwell’s isostatic stability criterion. As for the liquid state, after having validated the structural models by comparing the experimental findings available, we examine the dynamics of Ge-Se melts at ambient pressure. The investigations on the diffusion coefficients and viscosity at 1050 K showed clear anomalies, departing from the expectation that atomic mobility should decrease as the system becomes more and more rigid. Furthermore, the relaxation behavior at 1050 K also shows similar anomalies when intermediate scattering factors are examined at q vector corresponding to the principal peak position of the total structure factor. To elucidate this anomaly, we discuss the effect of the topological constraints on the dynamics in liquid state. The results show that the isostatic systems have slower dynamics as compared to flexible and stressed rigid phases. Moreover, we speculate that the reason of this anomaly may originate from the distribution of the topological bond bending constraints of the higher coordinated species (i.e. Ge) results. In particular, the flexible, and stressed rigid compositions showed a high variance in the Ge bond bending constraints whereas the isostatic composition forms a network in which the bond bending constraints are homogeneously distributed. We link this behavior with a global fragility concept for network forming liquids in such a way that fragility minima are obtained both by experimental findings and the calculated fragility values of the AIMD generated compositions (i.e. VFT or MYEGA fits) when scaled to the isostatic composition for a number of different systems. As for the glassy phase, the AIMD generated structural models show good agreement in both real and reciprocal space. The equation of state and normalized stress-strain curves are compared to the available experiments in order to verify the pressure behavior of the simulations. The results show a good agreement. In addition to the simulations under pressure, we show results of X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) experiments under pressure. Both simulations and the experiments show that there are no sign of crystallization during compression up to 42 GPa. One of the main important finding is the evolution of the Ge-Se bond length for the compositions studied. We observe a bond compression in the early stages of densification in the phase identified as low density amorphous (LDA), which is followed by an abrupt jump starting in pressures around 10-15 GPa, both in simulations and experiments. Furthermore, a semiconductor to metal transition is identified with the red shift in Ge K edge energy. The features of polyamorphism was also detected from the pressure evolution of the principal peak position of the structure factor which show two distinct slopes indicating different structural response to the applied pressure. In order to have a deeper understanding of the densification mechanisms, we apply neighbor analyses to our atomic trajectories and show that the tetrahedral to octahedral transformation (i.e LDA to HDA) starts to take place when the fifth and sixth neighbors effectively become the part of first shell neighbors, where the bond angles adapt themselves to 90 degrees. We furthermore speculate the effect of network rigidity of the glasses at ambient conditions onto the kinetics of the amorphous-amorphous transitions. It appears that the polyamorphic transitions are more sluggish as the network rigidity (i.e Ge content) increases. Finally we show that there is a universal threshold value in coordination change from LDA to HDA phases GexSe100􀀀x (where x 25) when scaled to reduced densities. [less ▲]

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See detailCoupled Boltzmann Equation Solver: Effects of the Electron-Phonon Interaction on the Transport Coefficients
Pike, Nicholas ULg; Dewandre, Antoine ULg; Verstraete, Matthieu ULg

Scientific conference (2016, September 22)

Recent experimental and theoretical calculations point to a complex interplay between the electron and phonon baths in a wide variety of materials [1,2]. We propose a method of coupling the Boltzmann ... [more ▼]

Recent experimental and theoretical calculations point to a complex interplay between the electron and phonon baths in a wide variety of materials [1,2]. We propose a method of coupling the Boltzmann equations for the electron and phonon baths within the relaxation time approximation which we use to calculate the thermoelectric transport coefficients. Our model for the coupled Boltzmann Equation solver includes analytic models, including ${\bf k \cdot p}$ Hamiltonians and tight-binding Hamiltonians, for both the electron and phonon energies and analytic models for the electron and phonon relaxation mechanisms. From these calculations we hope to better understand the role and interplay of electron-phonon and phonon-phonon interactions on the thermoelectric transport coefficients. [1] - Phys. Rev. Lett. ${\bf 114}$, 115901 (2015). [2] - PNAS ${\bf 112}$, 14777-14782 (2015). [less ▲]

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See detailNuclear Magnetic Resonance Metabolomic Profiling of Mouse Kidney, Urine and Serum Following Renal Ischemia/Reperfusion Injury.
Jouret, François ULg; Leenders, Justine ULg; Defraigne, Jean-Olivier ULg et al

in PLoS ONE (2016), 11(9), 1-14

Abstract BACKGROUND: Ischemia/reperfusion (I/R) is the most common cause of acute kidney injury (AKI). Its pathophysiology remains unclear. Metabolomics is dedicated to identify metabolites involved in ... [more ▼]

Abstract BACKGROUND: Ischemia/reperfusion (I/R) is the most common cause of acute kidney injury (AKI). Its pathophysiology remains unclear. Metabolomics is dedicated to identify metabolites involved in (patho)physiological changes of integrated living systems. Here, we performed 1H-Nuclear Magnetic Resonance metabolomics using urine, serum and kidney samples from a mouse model of renal I/R. METHODS: Renal 30-min ischemia was induced in 12-week-old C57BL/6J male mice by bilaterally clamping vascular pedicles, and was followed by 6, 24 or 48-hour reperfusion (n = 12/group). Sham-operated mice were used as controls. Statistical discriminant analyses, i.e. principal component analysis and orthogonal projections to latent structures (OPLS-DA), were performed on urine, serum and kidney lysates at each time-point. Multivariate receiver operating characteristic (ROC) curves were drawn, and sensitivity and specificity were calculated from ROC confusion matrix (with averaged class probabilities across 100 cross-validations). RESULTS: Urine OPLS-DA analysis showed a net separation between I/R and sham groups, with significant variations in levels of taurine, di- and tri-methylamine, creatine and lactate. Such changes were observed as early as 6 hours post reperfusion. Major metabolome modifications occurred at 24h post reperfusion. At this time-point, correlation coefficients between urine spectra and conventional AKI biomarkers, i.e. serum creatinine and urea levels, reached 0.94 and 0.95, respectively. The area under ROC curve at 6h, 24h and 48h post surgery were 0.73, 0.98 and 0.97, respectively. Similar discriminations were found in kidney samples, with changes in levels of lactate, fatty acids, choline and taurine. By contrast, serum OPLS-DA analysis could not discriminate sham-operated from I/R-exposed animals. CONCLUSIONS: Our study demonstrates that renal I/R in mouse causes early and sustained metabolomic changes in urine and kidney composition. The most implicated pathways at 6h and 24h post reperfusion include gluconeogenesis, taurine and hypotaurine metabolism, whereas protein biosynthesis, glycolysis, and galactose and arginine metabolism are key at 48h post reperfusion. [less ▲]

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See detailDouble-slit experiment in momentum space
Ivanov, Igor ULg; Seipt, Daniel; Surzhykov, Andrey et al

in Europhysics Letters (2016), 115(4), 41001

Young's classic double-slit experiment demonstrates the reality of interference when waves and particles travel simultaneously along two different spatial paths. Here, we propose a double-slit experiment ... [more ▼]

Young's classic double-slit experiment demonstrates the reality of interference when waves and particles travel simultaneously along two different spatial paths. Here, we propose a double-slit experiment in momentum space, realized in the free-space elastic scattering of vortex electrons. We show that this process proceeds along two paths in momentum space, which are well localized and well separated from each other. For such vortex beams, the (plane-wave) amplitudes along the two paths acquire adjustable phase shifts and produce interference fringes in the final angular distribution. We argue that this experiment can be realized with the present-day technology. We show that it gives experimental access to the Coulomb phase, a quantity which plays an important role in all charged particle scattering but which usual scattering experiments are insensitive to. [less ▲]

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