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See detailStructural identifiability analysis of a cardiovascular system model
Pironet, Antoine ULg; Dauby, Pierre ULg; Chase, J. Geoffrey et al

in Medical engineering & physics (2016)

The six-chamber cardiovascular system model of Burkhoff and Tyberg has been used in several theoretical and experimental studies. However, this cardiovascular system model (and others derived from it) are ... [more ▼]

The six-chamber cardiovascular system model of Burkhoff and Tyberg has been used in several theoretical and experimental studies. However, this cardiovascular system model (and others derived from it) are not identifiable from any output set. In this work, two such cases of structural non-identifiability are first presented. These cases occur when the model output set only contains a single type of information (pressure or volume). A specific output set is thus chosen, mixing pressure and volume information and containing only a limited number of clinically available measurements. Then, by manipulating the model equations involving these outputs, it is demonstrated that the six-chamber cardiovascular system model is structurally globally identifiable. A further simplification is made, assuming known cardiac valve resistances. Because of the poor practical identifiability of these four parameters, this assumption is usual. Under this hypothesis, the six-chamber cardiovascular system model is structurally identifiable from an even smaller dataset. As a consequence, parameter values computed from limited but well-chosen datasets are theoretically unique. This means that the parameter identification procedure can safely be performed on the model from such a well-chosen dataset. Thus, the model may be considered suitable for use in diagnosis. [less ▲]

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See detailSeasonal variability of surface and column carbon monoxide over megacity Paris, high altitude Jungfraujoch and Southern Hemispheric Wollongong stations
Té, Y; Jeseck, P; Franco, Bruno ULg et al

in Atmospheric Chemistry & Physics Discussions (2016)

Carbon monoxide (CO) is an atmospheric key species due to its toxicity and its impact on the atmospheric oxidizing capacity, both factors affecting air quality. The paper studies the altitude dependent ... [more ▼]

Carbon monoxide (CO) is an atmospheric key species due to its toxicity and its impact on the atmospheric oxidizing capacity, both factors affecting air quality. The paper studies the altitude dependent seasonal variability of CO at the three different sites Paris, Jungfraujoch and Wollongong, with an emphasis on establishing a link between the CO vertical distribution and the nature of CO emission sources. The CO seasonal variability obtained from the total columns and from the free tropospheric partial columns shows a maximum around March-April and a minimum around September-October in the Northern Hemisphere (Paris and Jungfraujoch). In the Southern Hemisphere (Wollongong) this seasonal variability is shifted by about 6 months. Satellite observations by IASI-MetOp and MOPITT instruments confirm this seasonality. Ground-based FTIR is demonstrated to provide useful complementary information due to good sensitivity in the boundary layer. In situ surface measurements of CO volume mixing ratios in Paris and at Jungfraujoch reveal a time-lag of the near surface seasonal variability of about 2 months with respect to the total column variability at the same sites. The chemical transport model GEOS-Chem is employed to interpret our observations. GEOS-Chem sensitivity runs allow identifying the emission sources influencing the seasonal cycle of CO. In Paris and on top of Jungfraujoch, the surface seasonality is mainly driven by anthropogenic emissions, while the total column seasonality is also controlled by air masses transported from distant sources. In the case of Wollongong, where the CO seasonality is mainly affected by biomass burning, no time shift is observed between surface and above the boundary layer. [less ▲]

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See detailAnalyse qualitative interdisciplinaire du discours de travailleurs à l’aide d’un logiciel collaboratif : le cas de la flexicurité
Beuker, Laura ULg; DE CIA, Julie ULg; Dervaux, Amélie ULg et al

in Recherches Qualitatives (2016), 35(1), 29-55

L’ambition de cet article est double : explorer les vertus de l’utilisation d’un logiciel d’analyse qualitative dans le cadre d’un travail interdisciplinaire sur la flexicurité, et réaliser une revue de ... [more ▼]

L’ambition de cet article est double : explorer les vertus de l’utilisation d’un logiciel d’analyse qualitative dans le cadre d’un travail interdisciplinaire sur la flexicurité, et réaliser une revue de littérature transversale à partir des problématiques concrètes que ce concept cristallise dans le vécu des travailleurs. La flexicurité constitue un oxymore qui prône la recherche d’un équilibre entre besoins de flexibilité et de sécurité sur le marché du travail. Cet équilibre est avant tout un objectif politique, mais il reste fragile aux yeux des acteurs concernés. En cherchant à croiser le regard analytique de trois disciplines – psychologie, gestion et sociologie –, nous avons recouru au logiciel Cassandre (Lejeune, 2008) pour dégager des tensions discursives autour des notions de flexibilité et de sécurité dans un corpus de vingt entretiens qualitatifs. L’article permet ainsi de concrétiser l’intérêt et les limites de l’utilisation d’un logiciel d’analyse qualitative dans le cadre d’un travail interdisciplinaire. [less ▲]

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See detailTénotomie chez le veau
Djebala, Salem ULg; Sartelet, Arnaud ULg

in Point Vétérinaire (2016), 363

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See detailSéance de cours : Presse et jeu vidéo
Dozo, Björn-Olav ULg; Krywicki, Boris ULg

Scientific conference (2016, March)

Cours sur la presse vidéoludique. Cinquième séance du cycle de conférences "Histoire et analyse des pratiques du jeu vidéo"

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See detailCalcifications articulaires, péri et juxtarticulaires « physiologiques » chez le chien
François, Marion; Bolen, Géraldine ULg

in Monde Vétérinaire (Le) (2016), (158), 14-17

Il existe, chez le chien, de nombreuses petites calcifications péri-, juxta- et articulaires « physiologiques » avec une présence inconstante, qui peuvent être confondues avec des lésions type fragment ... [more ▼]

Il existe, chez le chien, de nombreuses petites calcifications péri-, juxta- et articulaires « physiologiques » avec une présence inconstante, qui peuvent être confondues avec des lésions type fragment. Une bonne connaissance de leur localisation anatomique permet de distinguer les variations anatomiques normales des lésions pathologiques. Cet article reprend une liste de ces principales calcifications « physiologiques » pouvant être retrouvées sur des radiographies. [less ▲]

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See detailDisorders of Consciousness
Bodart, Olivier ULg; Thibaut, Aurore ULg; Laureys, Steven ULg et al

in Citerio, G.; Smith, M.; Kofke, A. (Eds.) Oxford Textbook of neurocritical care (2016)

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See detailReview of: K. Mulligan, Wittgenstein et la philosophie austro-allemande (Paris, 2012)
Seron, Denis ULg

in Dialectica : International Journal of Philosophy & Official Organ of the ESAP (2016), 70(1),

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See detailBad News in Service Encounters: Ideas and Insights
Delcourt, Cécile ULg; Gremler, Dwayne

Conference (2016, March)

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See detailFaraday rotation, band splitting, and one-way propagation of plasmon waves on a nanoparticle chain
Pike, Nicholas ULg; Stroud, David

in Journal of Applied Physics (2016), 119

We calculate the dispersion relations of plasmonic waves propagating along a chain of semiconducting or metallic nanoparticles in the presence of both a static magnetic field B and a liquid crystalline ... [more ▼]

We calculate the dispersion relations of plasmonic waves propagating along a chain of semiconducting or metallic nanoparticles in the presence of both a static magnetic field B and a liquid crystalline host. The dispersion relations are obtained using the quasistatic approximation and a dipole-dipole approximation to treat the interaction between surface plasmons on different nanoparticles. For plasmons propagating along a particle chain in a nematic liquid crystalline host with both B and the director parallel to the chain, we find a small, but finite, Faraday rotation angle. For B perpendicular to the chain, but director still parallel to the chain, the field couples the longitudinal and one of the two transverse plasmonic branches. This coupling is shown to split the two branches at the zero field crossing by an amount proportional to |B||B|. In a cholesteric liquid crystal host and an applied magnetic field parallel to the chain, the dispersion relations for left- and right-moving waves are found to be different. For some frequencies, the plasmonic wave propagates only in one of the two directions. [less ▲]

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See detailIncidence and risk factors for early renal dysfunction after liver transplantation.
WIESEN, Patricia ULg; MASSION, Paul ULg; JORIS, Jean ULg et al

in World journal of transplantation (2016), 6(1), 220-232

AIM: To determine renal dysfunction post liver transplantation, its incidence and risk factors in patients from a Belgian University Hospital. METHODS: Orthotopic liver transplantations performed from ... [more ▼]

AIM: To determine renal dysfunction post liver transplantation, its incidence and risk factors in patients from a Belgian University Hospital. METHODS: Orthotopic liver transplantations performed from January 2006 until September 2012 were retrospectively reviewed (n = 187). Patients with no renal replacement therapy (RRT) before transplantation were classified into four groups according to their highest creatinine plasma level during the first postoperative week. The first group had a peak creatinine level below 12 mg/L, the second group between 12 and 20 mg/L, the third group between 20 and 35 mg/L, and the fourth above 35 mg/L. In addition, patients who needed RRT during the first week after transplantation were also classified into the fourth group. Perioperative parameters were recorded as risk factors, namely age, sex, body mass index (BMI), length of preoperative hospital stay, prior bacterial infection within one month, preoperative ascites, preoperative treatment with beta-blocker, angiotensin-converting enzyme inhibitor or non steroidal anti-inflammatory drugs, preoperative creatinine and bilirubin levels, donor status (cardiac death or brain death), postoperative lactate level, need for intraoperative vasopressive drugs, surgical revision, mechanical ventilation for more than 24 h, postoperative bilirubin and transaminase peak levels, postoperative hemoglobin level, amount of perioperative blood transfusions and type of immunosuppression. Univariate and multivariate analysis were performed using logistic ordinal regression method. Post hoc analysis of the hemostatic agent used was also done. RESULTS: There were 78 patients in group 1 (41.7%), 46 in group 2 (24.6%), 38 in group 3 (20.3%) and 25 in group 4 (13.4%). Twenty patients required RRT: 13 (7%) during the first week after transplantation. Using univariate analysis, the severity of renal dysfunction was correlated with presence of ascites and prior bacterial infection, preoperative bilirubin, urea and creatinine level, need for surgical revision, use of vasopressor, postoperative mechanical ventilation, postoperative bilirubin and urea, aspartate aminotransferase (ASAT), and hemoglobin levels and the need for transfusion. The multivariate analysis showed that BMI (OR = 1.1, P = 0.004), preoperative creatinine level (OR = 11.1, P < 0.0001), use of vasopressor (OR = 3.31, P = 0.0002), maximal postoperative bilirubin level (OR = 1.44, P = 0.044) and minimal postoperative hemoglobin level (OR = 0.059, P = 0.0005) were independent predictors of early post-liver transplantation renal dysfunction. Neither donor status nor ASAT levels had significant impact on early postoperative renal dysfunction in multivariate analysis. Absence of renal dysfunction (group 1) was also predicted by the intraoperative hemostatic agent used, independently of the extent of bleeding and of the preoperative creatinine level. CONCLUSION: More than half of receivers experienced some degree of early renal dysfunction after liver transplantation. Main predictors were preoperative renal dysfunction, postoperative anemia and vasopressor requirement. [less ▲]

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See detailDouble genetic defect in a case of congenital hypogonadotropic hypogonadism
Potorac, Iulia ULg; Pintiaux, Axelle ULg; VALDES SOCIN, Hernan Gonzalo ULg et al

in Abstract book - 17th World Congress of Gynecological Endocrinology (2016, March)

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See detailActive Management of Low-Voltage Networks for Mitigating Overvoltages due to Photovoltaic Units
Olivier, Frédéric ULg; Aristidou, Petros ULg; Ernst, Damien ULg et al

in IEEE Transactions on Smart Grid (2016), 2(7), 926-936

In this paper, the overvoltage problems that might arise from the integration of photovoltaic panels into low-voltage distribution networks is addressed. A distributed scheme is proposed that adjusts the ... [more ▼]

In this paper, the overvoltage problems that might arise from the integration of photovoltaic panels into low-voltage distribution networks is addressed. A distributed scheme is proposed that adjusts the reactive and active power output of inverters to prevent or alleviate such problems. The proposed scheme is model-free and makes use of limited communication between the controllers, in the form of a distress signal, only during emergency conditions. It prioritizes the use of reactive power, while active power curtailment is performed only as a last resort. The behavior of the scheme is studied using dynamic simulations on a single low-voltage feeder and on a larger network composed of 14 low-voltage feeders. Its performance is compared to a centralized scheme based on the solution of an Optimal Power Flow problem, whose objective function is to minimize the active power curtailment. The proposed scheme successfully mitigates overvoltage situations due to high photovoltaic penetration and performs almost as well as the Optimal Power Flow based solution with significantly less information and communication requirements. [less ▲]

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See detailNovel composite heterozygous mutation of the receptor for hCG and LH leading to male disorder of sexual development
Potorac, Iulia ULg; FUDVOYE, Julie ULg; GAILLEZ, Stephanie ULg et al

in Abstract book - 17th World Congress of Gynecological Endocrinology (2016, March)

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See detailOption Replication and the Performance of a Market Timer
Hübner, Georges ULg

in Studies in Economics & Finance (2016), 33(1), 2-25

The Treynor and Mazuy framework is a widely used return-based model of market timing. However, existing corrections to the regression intercept can be manipulated through derivatives trading. We propose ... [more ▼]

The Treynor and Mazuy framework is a widely used return-based model of market timing. However, existing corrections to the regression intercept can be manipulated through derivatives trading. We propose an adjustment based on Merton's option replication approach. The linear and quadratic coefficients of the regression are exploited to assess the cost of the replicating option that yields similar convexity for a passive portfolio. A similar reasoning applies for various timing patterns and in multi-factor models. The proposed framework induces a potential rebalancing risk and involves the delicate issue of choosing the cheapest option. We show that these issues can be overcome for reasonable tolerance levels. [less ▲]

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See detailDynamics of upstream movements of the European eel Anguilla anguilla in an inland area of the River Meuse over the last 20 years
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg

in Environmental Biology of Fishes (2016), 99

The dynamics of upstream movements of the yellow eel Anguilla anguilla were investigated at Lixhe on the Belgian River Meuse in an inland fish pass regularly monitored from 1992 to 2014. Based on a ... [more ▼]

The dynamics of upstream movements of the yellow eel Anguilla anguilla were investigated at Lixhe on the Belgian River Meuse in an inland fish pass regularly monitored from 1992 to 2014. Based on a constant year-to-year sampling effort, we examined the abundance of ascending yellow eels and their body size, seasonal movement, and the associated water temperature and flow. Over the last 23 years, the number of ascending yellow eels has declined at an average 4.2% per year since 1992. The abundance of eels in 2014 is estimated at 4.5% of the ascending stock in 1992. We observed that some annual variations in eel abundance at Lixhe might be related to opening fish passes downstream of the study site. The results clearly demonstrated that long-term declining abundance of eels has resulted in increased sizes (mean increase, 4.1 mm per year since 1992) and temperatures triggering the upstream movement process (1.03°C per decade), with earlier dates for the last eel passages reducing the difference between temperature extremes of eel passages through the fish pass during the migration season. Eel movements occurred in spring and summer at low river discharge and were mainly triggered by high-temperature events. Eels have become larger with time because of improved feeding opportunities and more growth habitats available resulting from the long-term reduction in recruitment. This study highlights the importance of investigating long time spans for a better comprehension of the changes observed in yellow eels and for the optimization of management measures and future research. [less ▲]

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See detailAdolescence, et "double identité". Quand l’engagement radical violent devient une réponse à un questionnement identitaire
Garcet, Serge ULg

in L'Observatoire (2016), 86

L’engagement radical violent est caractérisé par la jeunesse de ses participants. Il apparaît comme une réponse individuelle à un questionnement identitaire dans lequel des processus cognitifs ... [more ▼]

L’engagement radical violent est caractérisé par la jeunesse de ses participants. Il apparaît comme une réponse individuelle à un questionnement identitaire dans lequel des processus cognitifs caractéristiques de l’adolescence sont associés aux représentations qu’engendre la problématique de la « double identité » chez les jeunes issus de l’immigration. L’article tente de décrire ce processus du point de vue psychologique tout en relevant le rôle déterminant tenu par les cognitions et les émotions sur l’adoption d’une posture victimaire derrière l’engagement radical. [less ▲]

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See detailGeschichtsvereine und Geschichtsbewusstsein in der DG (3. Teil)
Brüll, Christoph ULg

Article for general public (2016)

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