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See detailAnalgesia monitoring
BONHOMME, Vincent ULg

Conference (2016, April 14)

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See detailEpizootische Enteropathie bij konijnen : Verleden, heden en toekomst
Marlier, Didier ULg

Scientific conference (2016, April 13)

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See detail16e Franse studiedagen betreffende konijnenonderzoek
Marlier, Didier ULg

Scientific conference (2016, April 13)

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See detailEnvironmental monitoring: between science and decision-making
Richir, Jonathan ULg; Gobert, Sylvie ULg; Lejeune, Pierre et al

Scientific conference (2016, April 13)

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See detailDu bon usage du ralenti. Godard, Herzog : naissance de l'événement, mort du temps
Pieron, Julien ULg

Scientific conference (2016, April 13)

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See detailL'Aspiration panoramique en cinéma : allers et retours
Belloi, Livio ULg

Scientific conference (2016, April 13)

Dans le cadre de cette intervention, il s'agit de revenir sur la question de la vue panoramique, selon un double mouvement d'aller et de retour. L'aller se produit aux origines du cinéma (Alexandre Promio ... [more ▼]

Dans le cadre de cette intervention, il s'agit de revenir sur la question de la vue panoramique, selon un double mouvement d'aller et de retour. L'aller se produit aux origines du cinéma (Alexandre Promio, George Albert Smith, Billy Bitzer); le retour est à débusquer du côté du cinéma expérimental contemporain (Pelechian, Morrison), sur le mode de la rémanence et de la variation. [less ▲]

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See detailRytmes endocriniens circadiens
VALDES SOCIN, Hernan Gonzalo ULg

Scientific conference (2016, April 13)

A current research topic, that is developed in this presentation, is the study of disturbance of circadian hormonal cycles and the secretion of melatonin. Traumatic brain injury is associated to ... [more ▼]

A current research topic, that is developed in this presentation, is the study of disturbance of circadian hormonal cycles and the secretion of melatonin. Traumatic brain injury is associated to hypopituitarism in up to 10-35% of cases, depending on the dynamic tests used to diagnose hypopituitarism (Valdés-Socin & al 2009, Valdés-Socin & al 2015).Melatonin secretion and hormonal rhythms are severely disturbed in acute TBI patients (Seifman & al. Front Neurol 2014).Light is the primary variable that entrains the main circadian clock in the central nervous system. The retinohypothalamic tract generates an overt 24-hour rhythm. These coordinated outputs are conveyed through to the rest of the body via neuroendocrine (ie melatonin and ACTH-cortisol secretion), autonomic (sympathetic and parasympathetic pathways) and behavioral pathways (feeding, locomotor activity, etc).Finally, we will discuss some recent data connecting light pollution and nocturnal human activity with the metabolic syndrome (chronobesity). [less ▲]

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See detailLes genres du roman au XIXe siècle: introduction
Stienon, Valérie ULg; Pézard, Émilie

Conference (2016, April 13)

Le XIXe siècle a vu s’opérer le « sacre du roman » (Mona Ozouf). La promotion de ce genre anciennement déprécié est liée à l’entreprise de légitimation qu’ont menée, dans leurs œuvres, quelques grands ... [more ▼]

Le XIXe siècle a vu s’opérer le « sacre du roman » (Mona Ozouf). La promotion de ce genre anciennement déprécié est liée à l’entreprise de légitimation qu’ont menée, dans leurs œuvres, quelques grands romanciers du siècle, comme Balzac et Zola. Elle se manifeste aussi par l’augmentation quantitative des romans publiés, la diversification des supports éditoriaux (volumes, feuilletons, recueils) ainsi que celle des modes de diffusion (cabinets de lecture, collections, compilations). Ces différents facteurs induisent une « spécialisation du roman », c’est-à-dire une division du genre romanesque en de multiples sous-genres. Roman noir, personnel, sentimental, historique, d’aventures, de mœurs, de cape et d’épée, mondain, psychologique, scientifique ne sont que quelques-unes des catégories permettant aux contemporains de fragmenter un domaine romanesque devenu immense. Cette multiplication est facilitée par la possibilité de définir un genre à partir de nombreux critères, plus ou moins pertinents. D’autres genres ont été oubliés : qui se souvient du roman ecclésiastique ou du roman militaire ? Alors que de nombreux travaux ont déjà permis de préciser les connaissances sur un genre particulier, nous souhaiterions porter un regard englobant et transversal sur cette division du roman en de multiples genres, qui nous semble constituer un enjeu majeur pour l’étude de la production littéraire au XIXe siècle. [less ▲]

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See detailLow-rank plus sparse decomposition for exoplanet detection in direct-imaging ADI sequences. The LLSG algorithm
Gómez González, Carlos ULg; Absil, Olivier ULg; Absil, P.-A. et al

in Astronomy and Astrophysics (2016), 589

Context. Data processing constitutes a critical component of high-contrast exoplanet imaging. Its role is almost as important as the choice of a coronagraph or a wavefront control system, and it is ... [more ▼]

Context. Data processing constitutes a critical component of high-contrast exoplanet imaging. Its role is almost as important as the choice of a coronagraph or a wavefront control system, and it is intertwined with the chosen observing strategy. Among the data processing techniques for angular differential imaging (ADI), the most recent is the family of principal component analysis (PCA) based algorithms. It is a widely used statistical tool developed during the first half of the past century. PCA serves, in this case, as a subspace projection technique for constructing a reference point spread function (PSF) that can be subtracted from the science data for boosting the detectability of potential companions present in the data. Unfortunately, when building this reference PSF from the science data itself, PCA comes with certain limitations such as the sensitivity of the lower dimensional orthogonal subspace to non-Gaussian noise. <BR /> Aims: Inspired by recent advances in machine learning algorithms such as robust PCA, we aim to propose a localized subspace projection technique that surpasses current PCA-based post-processing algorithms in terms of the detectability of companions at near real-time speed, a quality that will be useful for future direct imaging surveys. <BR /> Methods: We used randomized low-rank approximation methods recently proposed in the machine learning literature, coupled with entry-wise thresholding to decompose an ADI image sequence locally into low-rank, sparse, and Gaussian noise components (LLSG). This local three-term decomposition separates the starlight and the associated speckle noise from the planetary signal, which mostly remains in the sparse term. We tested the performance of our new algorithm on a long ADI sequence obtained on β Pictoris with VLT/NACO. <BR /> Results: Compared to a standard PCA approach, LLSG decomposition reaches a higher signal-to-noise ratio and has an overall better performance in the receiver operating characteristic space. This three-term decomposition brings a detectability boost compared to the full-frame standard PCA approach, especially in the small inner working angle region where complex speckle noise prevents PCA from discerning true companions from noise. [less ▲]

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See detailMC2010 Shear Provisions and Recent Developments in Shear Research
Mihaylov, Boyan ULg

Conference (2016, April 13)

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See detailUltra-narrow superconducting junctions fabricated by controlled electromigration
Silhanek, Alejandro ULg

Conference (2016, April 12)

Superconducting nanowires have been, for years now, a topic of great interest due to their potential application in single photon detectors and in quantum computing circuits. In this context, it is of ... [more ▼]

Superconducting nanowires have been, for years now, a topic of great interest due to their potential application in single photon detectors and in quantum computing circuits. In this context, it is of fundamental importance to better understand the undesired and harmful appearance of thermal and quantum fluctuations of the superconducting order parameter as a function of the wire width. Although superconductors in the mesoscopic regime (i.e. size comparable to ξ and/or λ) have been explored both experimentally and theoretically in depth, the superconducting nanoworld (i.e. at scales of the fermi wavelength) has received much less attention. The lack of experimental results is in part due to the difficulty of sample fabrication, at dimensions beyond the limit reached by conventional lithographic techniques. A promising direction consists of controlling the local displacement of atoms by an electron wind, a process known as electromigration (EM). This effect relies on the combination of local temperature rise and substantial current crowding at nanoconstrictions. While uncontrolled, EM is responsible for the breakdown of small electronic devices, it can be used in a controllable way to further decrease locally the cross section of the nanowire towards single atomic contacts. In this work, we explore in-situ controlled EM to fabricate nano-constrictions immersed in cryogenic environment. We demonstrate that a transition from thermally assisted phase slips (TAPS) to quantum phase slips (QPS) takes place when the effective cross section becomes smaller than ~ 150 nm^2. In the regime dominated by QPS the nanowire loses completely its capacity to carry current without dissipation, even at the lowest possible temperature. We also demonstrate that the bow-tie shaped constrictions exhibit a negative magnetoresistance at low magnetic fields which can be attributed to the suppression of superconductivity in the contact leads. Strikingly, the detrimental effect caused by the repeated EM can be healed by simply inverting the current direction. These findings reveal the strong potential of the proposed fabrication method to explore various fascinating superconducting phenomena in atomic-size constrictions. [less ▲]

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See detailA Refined Method for Estimating the Global Hölder Exponent
Kleyntssens, Thomas ULg; Kreit, Damien; Nicolay, Samuel ULg

Conference (2016, April 12)

We give a wavelet characterization of the generalized Hölder spaces and show how this result can be applied to detect logarithmic corrections appearing in Brownian processes.

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See detailLe populisme en Europe: visages, défis et perspectives
Debras, François ULg

Conference given outside the academic context (2016)

Face aux élites nationales et internationales, politiques et économiques qui auraient confisqué le pouvoir aux citoyens, le populiste se présente comme le véritable défenseur du peuple. En faveur d'une ... [more ▼]

Face aux élites nationales et internationales, politiques et économiques qui auraient confisqué le pouvoir aux citoyens, le populiste se présente comme le véritable défenseur du peuple. En faveur d'une démocratie plus directe, plus proche du citoyen, le leader populiste s'oppose frontalement aux partis traditionnels jugés technocratiques, clientélistes, œuvrant au profit de certains intérêts particuliers et au détriment de l’intérêt général. Que signifie être populiste? Est-ce une idéologie ou une rhétorique? Quels partis, quelles personnalités politiques pouvons-nous qualifier de populistes? Le populisme est-il systématiquement opposé à la notion de démocratie, est-il "antisystème"? Au travers d'un tour de l'Europe et de certains partis en particulier, nous proposons d'apporter des clés de compréhension du populisme, un concept flou mais qui n'est certainement pas vide de sens. [less ▲]

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See detailImpact of tillage practices on soil moisture dynamics in a temperate climate: potential of 3-D electrical resistivity tomography (ERT)
Chelin, Marie ULg; Hiel, Marie-Pierre ULg; Blanchy, Guillaume et al

Poster (2016, April 12)

Adapted agricultural soil management practices can enhance soil health by providing improved aggregate stability and soil structural quality. Hence water infiltration may be improved and plant water ... [more ▼]

Adapted agricultural soil management practices can enhance soil health by providing improved aggregate stability and soil structural quality. Hence water infiltration may be improved and plant water availability increased. In this study, we aim at quantifying the effect of tillage practices on the water dynamics in a loamy soil under temperate climate (Gembloux, Belgium). Therefore, we evaluated the ability of electrical resistivity tomography to estimate the water content at the field scale and under complex field conditions: varying pore water conductivity, rainfall, crop water uptake, root growth, varying temperature and changing soil structure due to tillage practices. During the summer of 2015, we studied four different treatments: conventional spring and winter tillage, strip tillage and a bare soil. We used ERT to estimate the spatio-temporal distribution of soil moisture. In each of the plots, 2 time-domain reflectometry (TDR) probes and 2 suction cups were installed. A calibration trench was constructed with 4 electrodes, 1 TDR probe and 1 temperature sensor at 4 different depths. We quantified changes of porosity over the growing season using X-ray tomography. Combining these data, we will investigate and quantify the effect of simultaneously changing pore water conductivity, soil porosity, soil temperature and soil moisture on the effectiveness of time-lapse ER measurements as a proxy for soil moisture changes under different tillage practices. [less ▲]

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See detailInventaire et mise en collection d’espèces de pucerons et de parasitoïdes collectés en grandes cultures, et premier enregistrement de Metopolophium frisicum (Hille Ris Lambers 1947) et Acyrthosiphon primulae (Theobald 1913) (Hemiptera: Aphididae) en Belgique
Chevalier Mendes Lopes, Thomas ULg; Hatt, Séverin ULg; Starý, Petr et al

in Entomologie Faunistique = Faunistic Entomology (2016), 69

The purpose of this study was to identify aphid and parasitoid species that were collected in wheat and pea crops situated in Gembloux (Belgium), and conserve them into collections. To do so, yellow traps ... [more ▼]

The purpose of this study was to identify aphid and parasitoid species that were collected in wheat and pea crops situated in Gembloux (Belgium), and conserve them into collections. To do so, yellow traps (von Moericke) were used during 2012, 2013 and 2014 growing seasons. Fifty-two aphid species were identified and conserved in the entomological Conservatory of Gembloux. Among them, Metopolophium frisicum (Hille Ris Lambers 1947) and Acyrthosiphon primulae (Theobald 1913) were officially referenced for the first time in Belgium. Moreover, a collection composed by 16 parasitoid species was created. Their interest for biological control, as well as the methods that are studied in the laboratory of functional and evolutionary Entomology from Gembloux Agro-Bio Tech (University of Liège) to promote their presence in crops are discussed. [less ▲]

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See detailSTUDY AND CHARACTERIZATION OF MAGNETIC AND MULTIFERROIC MATERIALS BY FIRST-PRINCIPLES CALCULATIONS
Garcia Castro, Andrés Camilo ULg

Doctoral thesis (2016)

In the last fifteen years, multifunctional materials, and more specifically, multi- functional oxides have been widely studied due to its wide range of properties. Properties that go from ... [more ▼]

In the last fifteen years, multifunctional materials, and more specifically, multi- functional oxides have been widely studied due to its wide range of properties. Properties that go from superconductivity to ferroelectricity passing through mag- netism and multiferroism have been reported. Nonetheless, the fluoride family was left aside and little information is known about its possible ferroelectricity or mul- tiferroism. In this Ph.D thesis, we explored the electronic, vibrational, structural and magnetic properties of fluoride perovskite-based compounds. To such pur- poses, We performed ab-initio calculations based in the density-functional theory (DFT) as implemented in VASP and CRYSTAL codes. Our first step was to perform vibrational analyses in a large set of fluoroper- ovskites ABF3. Based on the results, we proposed a model that establishes an A-site geometrically driven ferroelectric vibrational instability in fluorides. Our studies reveal a different behavior as a function of isotropic pressure for NaBF3 with respect to oxides (e.g. BaTiO3) with B = Ca, V, Mn, and Zn. For these compounds we found an increase of the ferroelectric instability as a function of hydrostatic pressure. This probably due to the “transformation” of eigendisplace- ments responsible for the mode that creates the corresponding instability. In particular, an increase of ionic A-site radii present a strong influence in FE-polar instability. We also have shown, based on our first-principles calculations and symmetry theory analysis that all post-perovskites ABX3 with an active magnetic B-site cation can exhibit a noncollinear magnetic configuration, which happens to be allowed by symmetry. With these findings, the magnetic properties found exper- imentally were clarified for this particular high-pressure phase perovskite found at the Earth’s mantle. Additionally, We have predicted that NaMnF3 suffers a structural phase transition under pressure to a post-perovskite phase, where non- collinear ferromagnetism and large magnetic moment components are obtained within this high-pressure phase.. Going beyond, We have shown that it is possible to achieve multiferroic-induced state in NaMnF3 under epitaxial strain at compressive or tensile strain. We found a nonlinear behavior of the ferroelectric instability as well as a non-linear piezo- electric response as a function of epitaxial strain. The later completely different as the one found in oxide perovskites. Similarly, an out-of-plane polarization was observed, a property that has not been observed in oxides. We observed a Na + Mn sites cooperative ferroelectric ordering for compressive strain against a pure A-site geometrically driven ferroelectricity at tensile values of the ac-strain. Magnetic ordering reveals a non-collinear ground state with the GzAxFy repre- sentation. Even more interesting, and non-linear magnetoelectric coupling was found under the strained Pna1 ground state becoming the first known multifer- roic/magnetoelectric perovskite fluoride. Later, in order to go further, We studied the electronic and structural proper- ties of novel heterostructures based on oxyfluorides (KTaO3)n/(KBF3)l B = Zn and Ni interfaces. We found that the orbital levels splitting at the interfaces is strongly modified by the O–B–F coordination. The polar catastrophe phenomena also takes place in the oxyfluoride interfaces similarly to oxide heterostructure, however, we found that less number of layers are needed in order to achieve the insulator-to-metal transition when comparing to SrTiO3/LaAlO3 superlat- tices. We observed that the magnetism in the KTaO3/KNiF3 exhibits a moment magnitude modulations. Nevertheless, the magnetic structure keeps the G-type antiferromagnetism such as in the bulk former compound. Surprisingly, we ob- served a large k3-Rashba type splitting in at the oxyfluoride interfaces, at least four times larger than the one reported in SrTiO3/LaAlO3 interface and twice of the KTaO3-based transistor. In conclusion, we observed that fluorides-perovskites are good prototypes for multifunctional properties as oxides. Therefore, based on the results reported in this thesis, we expect that experimentalist and theoreticians can be motivated in characterization of fluorides, which can lead to a new set of unexplored materials with potential novel applications in electronics. [less ▲]

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See detailDocteur
Poskin, Antoine ULg

Doctoral thesis (2016)

During summer 2011, cattle presented severe hyperthermia combined with dropped milk yield and diarrhoea from unknown origin. In October 2011, blood was collected from cattle presenting these clinical ... [more ▼]

During summer 2011, cattle presented severe hyperthermia combined with dropped milk yield and diarrhoea from unknown origin. In October 2011, blood was collected from cattle presenting these clinical signs in Schmallenberg, a small city in West Germany. A new Orthobunyavirus, responsible for these unspecific clinical signs was identified and named Schmallenberg virus (SBV). Upon November 2011, an epizootic outbreak of abortion, stillbirths and malformed new-born was observed in bovine, ovine and caprine herds in Europe due to transplacental transmission of SBV to the foetus. The SBV vectors are small hematophagous midges of the gender Culicoides. This work contributed to estimate the impact of the SBV epidemic in Belgium (Study 1). On the basis of farmer’s observations, between 0.5% and 4% of calves were aborted, stillborn or malformed due to SBV in 2011-2012. Abortions and stillbirths were not clear consequences of the SBV outbreak in cattle. In sheep, between 11% and 19% of lambs were aborted, stillborn or malformed due to SBV in 2011-2012. Deformed animal was the most important finding of SBV outbreak at herd level and an essential condition for the farmer to send suspected samples to the National Reference Laboratory (NRL) for SBV analysis. The results gathered from the study indicate that SBV surveillance and monitoring should be implemented by SBV RNA detection with rRT-PCR in organs collected from stillborn and deformed calves and lambs born in big herds. The high impact of SBV highlighted in the Study 1 was putatively explained by unknown host supporting the SBV activity. In this respect, the role of pigs had never been evaluated. This was essential considering the suggested role of the domestic pigs in the life- cycle of the SBV-closely related Akabane virus (AKAV) (Huang et al., 2003). The absence of RNAemia after experimental infection of piglets with SBV realized in the Study 2 of the i thesis suggests the absence of obvious role of domestic pigs in SBV life-cycle. The absence of RNAemia is indeed a strong indication that further spread of SBV from the pigs to the Culicoides during a blood meal of the vector is not likely to occur, therefore making impossible an SBV transmission. The limited and temporary seroconversion observed after SBV inoculation in only half of the inoculated piglets and the absence of seroconversion reported in a limited number of field collected samples support this consideration. To prevent SBV progression, it was crucial to further study the pathogenesis of SBV. The Study 1 proved that the most important clinical impact of SBV was the consequence of the malformed new-born; hereto it was particularly crucial to improve the knowledge on the development of the SBV-related teratogenic effects. In this respect, experimental infection of pregnant sheep with SBV constituted an appropriate research approach. An experimental model was therefore essential to standardize. This thesis contributed to the standardization of in vivo experiments (in collaboration with another working group) by determining the minimum infectious dose of an SBV infectious inoculum. This reference infectious serum must contain approximately 20 TCID50 to induce a homogeneous effective infection in sheep. This dose is rather low and could be inoculated by a single Culicoides under natural conditions. Beyond this minimum infectious dose, no dose dependent effect was observed in productively inoculated ewes, either in the duration of the RNAemia, the quantity of SBV RNA detected by rRT–PCR in the blood, or in the number of SBV RNA copies present in the organs collected at necropsy. The experimental model developed (partly) in the Study 3 was used to inoculate pregnant ewes at day 45 and 60 of gestation, and increase the knowledge on SBV transplacental transmission. The inoculation induced the persistence of SBV RNA in placental organs until birth. Schmallenberg virus RNA was recovered from the organs collected at birth from the lambs of both groups. However, the chance to obtain SBV RNA positive placental ii organs was significantly higher when the infectious inoculum was inoculated at day 60 of gestation. Positive organs in lambs included CNS and muscle, but no malformation was observed in new-born lambs. This absence of malformations suggests that SBV inoculation must occur earlier than the day 45 of gestation to produce teratogenic effects in sheep. Also, the persistence of SBV RNA in the foetal envelope is indicative of a putative mean for SBV overwintering. The Study 4 highlighted a 6 month persistent seroconversion in the absence of SBV surinfection. In the meantime, SBV circulation drastically dropped on the field and the absence of SBV circulation could induce the sheep to become seronegative under natural conditions. In the Study 5, the experimental model developed in the Study 3 was used to demonstrate that one single SBV inoculation can induce a protective immunity in sheep that persists during a minimum period of 15 months. This experiment highlights that 2 successive periods of SBV circulation, spared of one year, is not likely to induce malformations on the field the second year. Based on the experience gathered with the closely related AKAV, recurrent outbreaks of congenital events can be expected for a long period. Vaccination of seronegative animals could be used to prevent the deleterious effects of SBV in case of SBV re-emergence. During this epidemic, different surveillance approaches including syndromic surveillance, sentinel herd surveillance, cross-sectional seroprevalence studies and pathogen surveillance in vectors have proven their utility and complementarity and should be considered to continue in the future in order to monitor the SBV dynamic. [less ▲]

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