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See detailEvaluation of the promethazine and acepromazine sedative and hemodynamic effects and norepinephrine reversal of acepromazine induced hemodynamic alterations in the standing horse
De Araujo Pequito, Manuel ULg

Doctoral thesis (2015)

Some phenothiazine derivates, such as acepromazine (ACP), have beneficial properties that could be interesting in equine patients with systemic inflammatory diseases where neutrophil activation and ROS ... [more ▼]

Some phenothiazine derivates, such as acepromazine (ACP), have beneficial properties that could be interesting in equine patients with systemic inflammatory diseases where neutrophil activation and ROS production are implicated. Besides, ACP’s vasodilatatory properties can also be of clinical importance in conditions such as acute laminitis or in anaesthetic protocols. However, the vasodilation induced by ACP is contraindicated in horses suffering from hypotension, a typical complication of systemic inflammatory diseases in horses. The sedative effect of ACP can also have an impact on the correct evaluation of the mental state of a horse in intensive care. Hence, it could be important either to select another phenothiazine derivate with the same beneficial effects as ACP, but with fewer undesirable effects, or to create a medication protocol, in which ACP is associated to another molecule, with the purpose of diminishing its undesired effects. Therefore, this work focused on the comparison of the sedative and peripheral hemodynamic effects of ACP and promethazine (PTZ) as well as on the evaluation of the hemodynamic effects of the administration of ACP followed by a norepinephrine (NOR) infusion in the standing healthy horse. To achieve this objective, 3 different studies were designed. The first one focused on the comparison between ACP and PTZ and the two other ones focused on the study of the association between ACP and NOR. In the first experimental protocol, 9 healthy Warmblood horses randomly received either intravenous ACP at 0.1 mg/kg or PTZ at 0.1, 0.2 or 0.3 mg/kg. A sedation score based on clinical examination was recorded, and systolic arterial blood pressure (SAP) was noninvasively evaluated using a Doppler flow detector at the tail, just before and every 15 minutes until 60 minutes after drug injection. Hemodynamics of the median artery of the left forelimb was studied using Doppler ultrasonography just before and 45 minutes after injection of the drug, which allowed calculation of surface (SURF), diameter (DIAM), and circumference (CIRC) of the vessel, as well as peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (MV), volumetric flow (VF), and resistivity index (RI) of the blood flow. In the second experimental protocol, an infusion of NOR at a constant rate of 1 μg/kg/minute for 15 minutes was administered to 5 standing healthy horses 45 minutes (TACP+45) after intravenous injection of ACP at 0.1 mg/kg. Non-invasive SAP and the same hemodynamic parameters than in study 1 were evaluated on the median artery. The SAP was evaluated before, 15, 30, 45 and every 5 minutes during the NOR infusion (TNORa, TNORb, TNORc) from TACP+45 to 60 minutes (TACP+60) after ACP administration and at 5 (TACP+65), 15 (TACP+75), 30 (TACP+90) and 45 (TACP+105) minutes after stopingt the NOR infusion. In the third experimental protocol, 45 minutes after ACP intravenous injection at 0.1 mg/kg, a continuous NOR infusion was performed during 10 minutes at 0.3 μg/kg/min, then 10 minutes at 0.5 μg/kg/min, and finally 10 minutes at 1 μg/kg/min in 5 standing healthy horses. Cardiac output (CO), stroke volume (SV) and systemic vascular resistance (SVR) were measured using lithium dilution (LiDCO). The mean (MAP), systolic and diastolic (DAP) systemic arterial pressures were measured invasively using an anesthesic monitoring system, that also automatically calculated the heart rate (HR). All parameters were measured immediately before ACP administration, 45 minutes after, at the end of each incremental 10 minutes NOR continuous infusion rate (TNOR0.3, TNOR0.5 and TNOR1) and ten minutes after terminating the NOR infusion. Regardless of the used dose, PTZ had lesser sedative and hypotensive effects than ACP at 0.1 mg/kg and did not induce significant variations in SURF, DIAM, CIRC, PSV, EDV, MV, VF, and RI of the studied standing horses. Conversely, the vasodilatory and hypotensive properties of ACP were illustrated by a significant increase in SURF, DIAM, CIRC, PSV, EDV, MV, and VF and a significant reduction of the RI and SAP. Unlike ACP, PTZ did not induce alterations on the morphology of the Doppler waveform. All the ACP-induced hemodynamic alterations, with the exception of PSV and MV were significantly counteracted by the NOR infusion at a constant 1 μg/kg/minute rate, from TNORa to TNORc for EDV, VF, MV and RI, and to TACP+65 for SAP, from TNORb to TACP+90 for CIRC and SURF and to TNORc for DIAM. Besides, although the ACP induced hypotension, no significant changes were observed in the CO, SV, SVR and HR. NOR infusion at incremental doses counteracted the decrease of SAP, from TNOR0.3 to TNOR1, of MAP at TNOR0.3 and TNOR1 and of DAP at TNOR1. After the ending of the infusion, the arterial pressure again dropped significantly, the CO and HR increased non significantly, and the SVR decreased non significantly. PTZ appears to have less sedative and peripheral vasodilator effects than ACP, thus it could be safer than ACP in patients suffering from hypotension. The results also demonstrate that a NOR infusion can reverse ACP’s vasodilatory effects, restoring hemodynamic parameters and blood pressure in horses. The studied NOR infusion proved hence to be useful in horses suffering from vasodilation and hypotension, as it reverted the hemodynamic alterations induced by ACP. [less ▲]

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See detailA Non-Local Damage-Enhanced Incremental-Secant Mean-Field-Homogenization For Composite Laminate Failure Predictions
Wu, Ling ULg; Adam, Laurent; Doghri, Issam et al

Conference (2015, July 06)

Recently, the authors have presented an incremental-secant mean-field homogenisation (MFH) process for non-linear composite materials [4]. In this formulation, a virtual elastic unloading is applied to ... [more ▼]

Recently, the authors have presented an incremental-secant mean-field homogenisation (MFH) process for non-linear composite materials [4]. In this formulation, a virtual elastic unloading is applied to evaluate the virtual residual stress and strain states reached in each elasto-plastic phase. These virtual states are then used as a starting point to apply a secant homogenization method. This incremental-secant MFH process can handle non-proportional and nonmonotonic loadings, and naturally possesses an isotropic instantaneous stiffness operator to be used in the Eshelby tensor. This incremental-secant MFH homogenization can account for the first and second statistical moment estimation of the current yield stress in the composite phases during the computation of the plastic flow. When accounting for a second statistical moment estimation, the plastic yield in the composite material phases is captured with a higher accuracy, improving the predictions, mainly in the case of short fiber composite materials [6], see Fig. 1(a). The incremental MFH can handle material softening when extended to include a damage model. Indeed, as the secant formulation is applied from an unloaded state, the inclusion phase can be elastically unloaded during the softening of the matrix phase, contrarily to the case of the incremental-tangent method [3, 5], see Fig. 1(b). Moreover, when formulating the damage model in the composite phases in a non-local way, as with the non-local implicit approach, [1, 2], the MFH scheme can be used to model strain localization in composite structures [5], without suffering from the loss of the solution uniqueness. [less ▲]

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See detailPhytoplankton abundance and diversity in the Congo river at high and low waters
Stoyneva, MP; Descy, JP; Bouillon, S et al

Conference (2015, July 05)

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See detailLa paix de Westphalie (1648) : une rupture dans l’histoire diplomatique du Saint-Siège ? Confessionnalisation et médiation pontificale en question.
Regibeau, Julien ULg

Conference (2015, July 04)

La signature des traités de Westphalie, en 1648, a longtemps été considérée comme une rupture nette dans l’histoire politico-religieuse. Elle aurait conduit à l’effondrement de la christianitas médiévale ... [more ▼]

La signature des traités de Westphalie, en 1648, a longtemps été considérée comme une rupture nette dans l’histoire politico-religieuse. Elle aurait conduit à l’effondrement de la christianitas médiévale et à la naissance de l’Europe des États modernes . Ce changement de paradigme supposerait l’échec à long terme de la politique du Saint-Siège. L’historiographie récente permet cependant de revoir cette double interprétation, montrant notamment que le rôle diplomatique joué par Rome lors des négociations en Westphalie est plus complexe. Le but de ma communication est de réévaluer la théorie qui voudrait que la paix de Westphalie soit une rupture pour l’histoire des relations internationales et, par voie de conséquence, pour la diplomatie pontificale. Premièrement, je mets en avant les critères qui poussent régulièrement les historiens à envisager cette paix comme une défaite de Rome. Cette première partie m’entraine ensuite à définir rapidement le concept de confessionnalisation des relations internationales et à montrer qu’il est aujourd’hui réinterrogé par la recherche. Ce concept fait de la lutte confessionnelle le principal facteur structurant les relations internationales entre 1550 et 1650. Or il semble aujourd’hui peu à même d’expliquer toute la diversité des discours et des pratiques qui apparaissent alors dans les correspondances diplomatiques, y compris celles des ambassadeurs du Saint-Siège. Dans un troisième temps, je me concentre plus spécifiquement sur la figure du pape comme padre comune des princes catholiques et donc médiateur de leurs conflits. Ce rôle mérite d’être appréhendé dans le détail de chaque négociation. L’étude de la médiation des nonces ordinaires à l’époque des congrès en Westphalie permettrait ainsi de proposer une nouvelle lecture du rôle joué par la papauté à l’occasion de cette paix. Cela permettrait également d’adjoindre, à la temporalité de la confessionnalisation, d’autres temporalités parallèles. [less ▲]

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See detailBrouillages ou articulations des temps ? Valeur épistémique du discontinu en histoire
Servais, Amandine ULg

Scientific conference (2015, July 04)

Cette communication tente de révéler les enjeux historiographiques d’une conception non linéaire du temps, un temps irréductiblement marqué du sceau de la discontinuité. Cette conception du temps comme ... [more ▼]

Cette communication tente de révéler les enjeux historiographiques d’une conception non linéaire du temps, un temps irréductiblement marqué du sceau de la discontinuité. Cette conception du temps comme dynamique toujours en devenir engage tout le dispositif historien et implique un « faire de l’histoire » différent. Les inflexions, césures, ruptures, voire survivances qui non seulement déterminent les temporalités mais qui confèrent aux phénomènes eux-mêmes leur singularité – ce qui, en eux, échappe à la régularité – imposent à l’historien une pratique originale qui lui permet de reconnaître le discontinu là où, souvent, l’on préfère fabriquer un enchaînement implacable de causes et d’effets, un entrelacs cohérent de faits – du continu, en somme. Je mène cette réflexion au départ de l’étude d’un cas, celui de l’historienne Arlette Farge. Sa conception du temps, et donc des phénomènes historiques – leur caractère intrinsèquement irrégulier et éclaté –, l’a conduite à élaborer un récit de connaissance que je qualifierai d’ « épique » (en référence au théâtre épique de Brecht). Le récit épique refuse tout schéma narratif préétabli ; il est composé de ruptures, d’irruptions, d’infléchissements et de césures, à l’instar des faits dont il rend compte. Partant, les vertus de la forme épique, pour la discipline historique, sont indéniables. 1) Elle débouche sur un récit de connaissance très respectueux de son matériau puisqu’il en adopte les qualités. 2) L’historiographie épique présente, de plus, une fonction critique. Elle permet de ne pas se laisser « endormir » par des explications historiennes lissantes, par des synthèses qui risquent d’aplanir les faits, d’en dénier la complexité. En introduisant du dissensus, l’épique permet de contrer le danger auquel ne résistent pas toujours les discours historiens plus traditionnels : le finalisme historique servi par un respect scrupuleux du schéma narratif romanesque. [less ▲]

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See detailLimites temporelles et conceptualisation de l'écrivain
Daubercies, Laurence ULg

Conference (2015, July 04)

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See detailLes futurs discontinus de l’anticipation : strates, réversions et ruptures temporelles
Stienon, Valérie ULg

Scientific conference (2015, July 03)

La qualité du récit d’anticipation est souvent estimée à la mesure de ses coïncidences avec les données du monde de référence. Cette lecture factuelle tend à prévaloir pour la réception des genres de ... [more ▼]

La qualité du récit d’anticipation est souvent estimée à la mesure de ses coïncidences avec les données du monde de référence. Cette lecture factuelle tend à prévaloir pour la réception des genres de l’imaginaire du futur, dans lesquels on décèle volontiers tantôt une fonction prédictive – cognitive ou de mise en garde –, tantôt un éloignement dépaysant avec les réalités connues. On a moins considéré les temporalités internes de ces récits, tout aussi intéressantes que leur mise en relation avec les données du monde. Les chronologies diégétiques et les visions de l’Histoire sur lesquelles ils reposent montrent que ces mondes fictifs entretiennent avec leur propre temporalité – passée, présente et future – des rapports pour le moins complexes, faits de nombreux décrochages et d’emboîtements divers. Comment le roman d’anticipation les aménage-t-il, les comble-t-il, voire les justifie-t-il dans le cadre de son dispositif narratif ? À partir d’exemples empruntés à une histoire littéraire de l’anticipation française encore peu connue pour la période 1840-1940 (Souvestre, Henriot, Messac, Paulin, etc), on examinera quelques manières romanesques de questionner le cours du temps et de remettre en question une chronologie linéaire téléologique. En particulier, les cas de figures suivants seront détaillés : • strates : rétrofuturisme convoquant une double temporalité future, dont l’une contient l’autre • réversions : vision cyclique de l’Histoire associée à une involution ou un déclin • ruptures : mondes possibles hors temps, sans passé ou à la temporalité bouclée [less ▲]

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See detailL'école rebondit au coeur des malentendus : résultats de recherches croisées quantitatives et qualitatives
Gavray, Claire ULg

Scientific conference (2015, July 03)

Le vécu et les représentations scolaires des professeurs d'enseignement technique et professionnelle contrastent grandement avec la description qu'en font les medias. Les équipes enseignantes qui ... [more ▼]

Le vécu et les représentations scolaires des professeurs d'enseignement technique et professionnelle contrastent grandement avec la description qu'en font les medias. Les équipes enseignantes qui implémentent un projet pédagogique alternatif emploient régulièrement le terme de malentendus : comme outil à partir duquel construire -patiemment mais avec résutltt- le dialogue avec les autres acteurs de l'école ; au négatif pour décrire les évolutions 'macros' qu'ils décrient 'ce n'est pas un malentendu'.... [less ▲]

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See detailSynécismes et transformations du paysage religieux en Grèce antique
Palamidis, Alaya ULg

Conference (2015, July 03)

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See detailAFM for monitoring the elongation of amyloid fibrils made of polyQ proteins
Willet, Nicolas ULg; Bastin, Frédérique ULg; Dorval, Frédéric ULg et al

Scientific conference (2015, July 02)

Several neurodegenerative disorders, called polyglutamine (polyQ) diseases, are associated with the aggregation into amyloid fibrils of proteins containing an expanded polyQ tract (>35-45 Q). Amyloid ... [more ▼]

Several neurodegenerative disorders, called polyglutamine (polyQ) diseases, are associated with the aggregation into amyloid fibrils of proteins containing an expanded polyQ tract (>35-45 Q). Amyloid fibrils are proteinaceous aggregates with a helical organization. Such assemblies contain a large amount of b-sheet secondary structures. How do non-polyQ regions of the proteins interfere with the propensity of polyQ tracts to trigger fibril formation? The aim of this study is a better understanding of the role of polyQ and non-polyQ regions on the elongation of amyloid fibril. By performing fibril elongation in the presence of various chimeras and in different conditions, the aim is to unravel the effect of each parameter in general, and of the protein context in particular, on the elongation rate. This requires AFM imaging in complement to QCM experiments. Imaging parameters have to be optimized for such sensitive and nanosized samples. Accurate measurement of fibril elongation rate is performed by quartz crystal microbalance (QCM) and sensor surfaces are imaged by atomic force microscopy (AFM) before and after the elongation step. BlaP is an ideal host protein, in order to better understand how non-polyQ regions interfere with the aggregation process of polyQ proteins. BlaP chimeras are a good model system because there is a Q-treshold for fibril formation ; the longer the polyQ, the faster the aggregation ; conformation and insertion site are critical. [less ▲]

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See detailSurveillance à long terme de l'atmosphère terrestre depuis la station du Jungfraujoch
Mahieu, Emmanuel ULg

Conference (2015, July 02)

Nous présentons une vue d'ensemble des activités menées par les chercheurs de l'Université de Liège à la station scientifique internationale du Jungfraujoch, depuis les observations infrarouges pionnières ... [more ▼]

Nous présentons une vue d'ensemble des activités menées par les chercheurs de l'Université de Liège à la station scientifique internationale du Jungfraujoch, depuis les observations infrarouges pionnières effectuées à ce site par le Pr Migeotte en 1950-1951. L'accent est mis sur les données géophysiques et les séries temporelles déduites pour les constituants de l'atmosphère influençant le climat. [less ▲]

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See detailMalentendu visuel et folie : Test de Rorschach et hyper-conscience
Englebert, Jérôme ULg

Conference (2015, July 02)

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See detailMaking-doing sensory perception: how to teach taste
Vangeebergen, Thomas ULg

Conference (2015, July 02)

Imagine a course of “olfaction and tasting”, in a notorious professional school for flavourist and perfumers in France. The aim of the teacher is to instil sensory referential sources in students, by the ... [more ▼]

Imagine a course of “olfaction and tasting”, in a notorious professional school for flavourist and perfumers in France. The aim of the teacher is to instil sensory referential sources in students, by the appropriation of a rigorous vocabulary and through practical tries of molecules and preparations. To name, to compare, to memorize, to describe and to value these substances are the tasks of the group during two years. As the general topic of the research was to understand professional skills about taste, one of the issues consisted in studying the development of these specific abilities. The focus was on the techniques deployed to install a sensory common frame, alternatively through a research of a bottom- up consensus and some imposed tags. The teacher, who has to transfer a substantial amount of sensory references to the class in narrow times, and to make them able to master those notions, has to face to a double constraint. She must transmit a core-sensorium, but at the same time has to support students’ own contributions, in mode to open the reference document to necessary enrichments. More than « actors », or « informants », the teacher and the students were also masters for me, by contributing to my sensory education. But also when they have confronted me to delicates questions and issues, sometimes against my own first researches. They were what I called though co-inquirer, proposing contradictory and resistant interpretations of the world, teaching me how to realize the study of sensory. [less ▲]

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See detailGaz à effet de serre indirects et qualité de l'air aux latitudes moyennes de l'hémisphère nord : tendances à long terme et variabilité déduites de télémesures effectuées au Jungfraujoch (Alpes suisses, 3580 m)
Franco, Bruno ULg; Bader, Whitney ULg; Lejeune, Bernard ULg et al

Conference (2015, July 01)

Indirect greenhouse gases and air quality at Northern Hemisphere mid-latitudes: long-term trends and variability derived from ground-based remote sensing at Jungfraujoch (Swiss Alps, 3580 m a.s.l.). We ... [more ▼]

Indirect greenhouse gases and air quality at Northern Hemisphere mid-latitudes: long-term trends and variability derived from ground-based remote sensing at Jungfraujoch (Swiss Alps, 3580 m a.s.l.). We present an overview of recent investigations conducted by the Solar and Atmospheric Physics Infrared Group at the University of Liège and dedicated to the long-term monitoring of atmospheric gases with an indirect greenhouse effect and affecting air quality at Northern Hemisphere mid-latitudes. Gas concentrations are derived from high-resolution solar spectra recorded at the Jungfraujoch station (Swiss Alps, 46.5° N, 8.0° E, 3580 m a.s.l.), using Fourier transform infrared spectrometers. Time series obtained from these observations, along with satellite measurements and simulations from numerical models, allow for the study of both variability and recent evolution of these species and are critical for air quality monitoring and understanding climate changes. [less ▲]

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See detailPolarization alignments of quasars from the JVAS/CLASS 8.4-GHz surveys
Pelgrims, Vincent ULg; Hutsemekers, Damien ULg

in Monthly Notices of the Royal Astronomical Society (2015), 450

We test the hypothesis that the polarization vectors of flat-spectrum radio sources (FSRSs) from the JVAS/CLASS 8.4-GHz surveys are randomly oriented in the sky. A sample with robust polarization ... [more ▼]

We test the hypothesis that the polarization vectors of flat-spectrum radio sources (FSRSs) from the JVAS/CLASS 8.4-GHz surveys are randomly oriented in the sky. A sample with robust polarization measurements is made with 4155 objects. Redshift information is known for 1531 of them. We performed two statistical analyses: one in two dimensions and the other in three dimensions when distance is available. We find significant large-scale alignments of polarization vectors for samples containing only quasars among the varieties of FSRS. While these correlations prove difficult to explain either by a physical effect or by biases in the data set, that the quasars that have significantly aligned polarization vectors are found in regions of the sky where optical polarization alignments were previously found is striking. [less ▲]

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