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See detailINVESTIGATION OF PARAMETERS AFFECTING VOLTAGE SECURITY OF THE HELLENIC INTERCONNECTED SYSTEM
Christoforidis, George; Kabouris, John; Vournas, Costas et al

(2005, August)

The Hellenic Interconnected System pre-sents a structural geographical imbalance between generation sites and load centers. This imbalance leads to bulk power transfers on long electrical distances ... [more ▼]

The Hellenic Interconnected System pre-sents a structural geographical imbalance between generation sites and load centers. This imbalance leads to bulk power transfers on long electrical distances leading to voltage stability problems. In order to improve the opera-tional practices aiming at improving the voltage security, an on-line Voltage Security Assessment tool has been installed at the National Control Center of the Hellenic Transmission System Operator that operates and controls the interconnected power system of Greece. This paper presents some indicative results obtained by the use of this tool. The analysis includes the investigation of the main parameters that affect the voltage stability of the system, such as the position of non-automatic taps of autotrans-formers, the network topology, and the spatial distribution of generation. [less ▲]

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See detailFeedback mechanisms for global oscillations in Lure systems
Sepulchre, Rodolphe ULg; Stan, G. B.

in Systems & Control Letters (2005), 54(8), 809-818

The paper presents two mechanisms for global oscillations in feedback systems, based on bifurcations in absolutely stable systems. The external characterization of the oscillators provides the basis for a ... [more ▼]

The paper presents two mechanisms for global oscillations in feedback systems, based on bifurcations in absolutely stable systems. The external characterization of the oscillators provides the basis for a (energy-based) dissipativity theory for oscillators, thereby opening new possibilities for rigorous stability analysis of high-dimensional systems and interconnected oscillators. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailOxygen influence on the ß-oxidative metabolism of methyl ricinoleate for lactones production by the yeast Yarrowia lipolytica
Aguedo, Mario ULg

in Proceedings of the 2nd Mercosur Congress on Chemical Engineering – ENPROMER and 4th Mercosur Congress on Process Systems Engineering (2005, August)

The yeast Yarrowia lipolytica is able to carry out the peroxisomal b-oxidative catabolism of methyl ricinoleate, a process leading notably to the production of g-decalactone, a high-value aroma compound ... [more ▼]

The yeast Yarrowia lipolytica is able to carry out the peroxisomal b-oxidative catabolism of methyl ricinoleate, a process leading notably to the production of g-decalactone, a high-value aroma compound. In fact, this metabolic pathway gives rise to different C10 lactones and their accumulations report the efficiency of the peroxisomal beta-oxidation enzymes. gamma-Decalactone or 3-hydroxydecan-4-olide accumulate when acyl-CoA oxidase or 3-hydroxyacyl-CoA dehydrogenase, respectively, control the flux within the pathway. We investigated the accumulation of C10 lactones in various aeration conditions. An important accumulation of 3-hydroxydecan-4-olide was observed when increasing the aeration up to a certain point, above it its concentration was lowered, which indicates a stimulation of the activity of 3-hydroxyacyl-CoA dehydrogenase. Cultures under high-pressure were performed in order to increase the oxygen in the medium by an alternative mean. Y. lipolytica growth in glucose medium was accelerated at 0.5 MPa of total air pressure. A decrease in g-decalactone production was observed with the increase in pressure. Curiously, applying a pressure of 0.5 MPa during growth and then during biotransformation resulted in high decenolides concentrations. [less ▲]

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See detailImpact of surface properties of lactic acid bacteria on the stability of emulsions
Ly, M. H.; Waché, Y.; Bouchez-Naïtali, M. et al

in Proceedings of the 2nd Mercosur Congress on Chemical Engineering – ENPROMER and 4th Mercosur Congress on Process Systems Engineering (2005, August)

Bacteria have physicochemical surface properties which depend on the chemical composition of the cell surface. These characters proceed from several type of physicochemical interactions and are involved ... [more ▼]

Bacteria have physicochemical surface properties which depend on the chemical composition of the cell surface. These characters proceed from several type of physicochemical interactions and are involved in attachment processes of microorganisms to surfaces. Thus they are of interest in several areas, as biomedicine, formation of biofilms and adhesion to apolar surfaces. Moreover, food matrix are complex heterogeneous media, which structure settles on interaction forces between molecules (van der Waals, electrostatic or structural forces…). When bacteria are present in a matrix, it is probable that their surface interacts with the other constituents. So far, few studies have mentioned this subject. In order to understand the involvement of cells surface properties in a food matrix, the effect of surface properties of lactic bacteria on the stability of model emulsions were studied. The results showed that the choice of a bacterium according to its surface properties may have a strong impact on the stability and on the behavior of an emulsion. [less ▲]

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See detail• Caractérisation hydrochimique et qualité des eaux souterraines du projet hydraulique villageois 310 forages dans la boucle du Mouhoun dans les provinces des Banwa des Balés, Mouhoun et de la Kossi (Burkina Faso)
Sauret, Elie ULg

Master of advanced studies dissertation (2005)

Le projet hydraulique villageoise dont a été bénéficiaire les provinces des Banwa, du Mouhoun, de la Kossi, et des Bales a permis de réaliser 310 forages entre 1998 et 2004. Cette opportunité offerte aux ... [more ▼]

Le projet hydraulique villageoise dont a été bénéficiaire les provinces des Banwa, du Mouhoun, de la Kossi, et des Bales a permis de réaliser 310 forages entre 1998 et 2004. Cette opportunité offerte aux communautés rurales de la Boucle du Mouhoun est salutaire au regard des difficultés d’alimentation en eau potable des populations de la région. Toutefois, l’occurrence de fer, zinc et nitrites dans les eaux de forages à des concentrations supérieures aux normes admises par l’OMS indique un réel problème de potabilité. Au total, 63 forages présentent des anomalies en fer (teneurs > 0.3mg/l) et 14 forages des anomalies en zinc (teneurs > 5 mg/l). Les forages à teneur anomale en nitrites (teneurs > 0.1 mg/l) sont au nombre de 49. La plus grande majorité des forages à teneurs anomales en fer sont implantés dans les aquifères cristallins et gréseux de type fissuré (notamment dans les provinces des Balés et sur sa bordure avec la province du Mouhoun). Les aquifères constitués de schistes et argilites semblent beaucoup moins affecté par ce type de pollution. Le fer et le zinc montre une même dynamique d’accumulation dans les eaux de forages. Cette accumulation serait liée à des processus de réduction par les microorganismes. Les formations cristallines et gréseuses de type fissuré rencontrées dans les zones parcourues par les mégalinéaments (province des Balés, du Mouhoun et de la Kossi) constituent les types d’aquifères les plus affectés par la pollution des nitrites résultant des pratiques agricoles et culturales (utilisation de fertilisants azotés, brûlis des résidus cotonniers, pratique de fosses fumiers). Des poches de pollution par les nitrites ont été identifiées dans les systèmes aquifères gréseux et schisteux de type altéré (province des Banwa et bordure orientale de la province du Mouhoun). Elles seraient liées à l’infiltration des eaux rejetées par l’unité industrielle de traitement du coton localisée dans le département de Solenzo (province des Banwa où les sols présentent un bon drainage : sols minéraux bruts et à sesquioxydes de fer et manganèse). [less ▲]

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See detailDynamics of a bouncing dimer
Dorbolo, Stéphane ULg; Volfson, D.; Tsimring, L. et al

in Physical Review Letters (2005), 95(4),

We investigate the dynamics of a dimer bouncing on a vertically oscillated plate. The dimer, composed of two spheres rigidly connected by a light rod, exhibits several modes depending on initial and ... [more ▼]

We investigate the dynamics of a dimer bouncing on a vertically oscillated plate. The dimer, composed of two spheres rigidly connected by a light rod, exhibits several modes depending on initial and driving conditions. The first excited mode has a novel horizontal drift in which one end of the dimer stays on the plate during most of the cycle, while the other end bounces in phase with the plate. The speed and direction of the drift depend on the aspect ratio of the dimer. We employ event-driven simulations based on a detailed treatment of frictional interactions between the dimer and the plate in order to elucidate the nature of the transport mechanism in the drift mode. [less ▲]

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See detailLimitation of the Pupil Replication Technique in the Presence of Instrumental Defects
Riaud, Pierre ULg; Mawet, Dimitri; Absil, Olivier ULg

in Astrophysical Journal Letters (2005), 628

Pupil replication has been proposed by Greenaway et al. as a new optical technique to improve the suppression of starlight in high dynamic imaging. This Letter extends numerical simulations in the two ... [more ▼]

Pupil replication has been proposed by Greenaway et al. as a new optical technique to improve the suppression of starlight in high dynamic imaging. This Letter extends numerical simulations in the two-dimensional case with various realistic imperfections (surface error, chromatic smearing, and pupil shift). These results demonstrate some strong limitations compared to single-pupil apodization techniques for exoplanet detection. [less ▲]

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See detailBudgeting sinks and sources of CO2 in the coastal ocean: Diversity of ecosystems counts
Borges, Alberto ULg; Delille, Bruno ULg; Frankignoulle, M.

in Geophysical Research Letters (2005), 32(14),

Air-water CO2 fluxes were up-scaled to take into account the latitudinal and ecosystem diversity of the coastal ocean, based on an exhaustive literature survey. Marginal seas at high and temperate ... [more ▼]

Air-water CO2 fluxes were up-scaled to take into account the latitudinal and ecosystem diversity of the coastal ocean, based on an exhaustive literature survey. Marginal seas at high and temperate latitudes act as sinks of CO2 from the atmosphere, in contrast to subtropical and tropical marginal seas that act as sources of CO2 to the atmosphere. Overall, marginal seas act as a strong sink of CO2 of about -0.45 Pg C yr(-1). This sink could be almost fully compensated by the emission of CO2 from the ensemble of near-shore coastal ecosystems of about 0.40 Pg C yr(-1). Although this value is subject to large uncertainty, it stresses the importance of the diversity of ecosystems, in particular near-shore systems, when integrating CO2 fluxes at global scale in the coastal ocean. [less ▲]

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See detailFactors that influence physicians' detection of distress in patients with cancer - Can a communication skills training program improve physicians' detection?
Merckaert, Isabelle; Libert, Yves; Delvaux, Nicole et al

in Cancer (2005), 104(2), 411-421

BACKGROUND. No study to date has assessed the impact of skills acquisition after a communication skills training program on physicians' ability to detect distress in patients with cancer. METHODS. First ... [more ▼]

BACKGROUND. No study to date has assessed the impact of skills acquisition after a communication skills training program on physicians' ability to detect distress in patients with cancer. METHODS. First, the authors used a randomized design to assess the impact, on physicians' ability to detect patients' distress, of a 1-hour theoretical information course followed by 2 communication skills training programs: a 2.5-day basic training program and the same training program consolidated by 6 3-hour consolidation workshops. Then, the investigate contextual, patient, and communication variables or factors associated with physicians' detection of patients' distress were investigated. After they attended the basic communication skills training program, physicians were assigned randomly to consolidation workshops or to a waiting list. Interviews with a cancer patient were recorded before training, after consolidation workshops for the group that attended consolidation workshops, and approximate to 5 months after basic training for the group that attended basic training without the consolidation workshops. Patient distress was recorded with the Hospital Anxiety and Depression Scale before the interviews. Physicians rated their patients' distress on a visual analog scale after the interviews. Physicians' ability to detect patients' distress was measured through computing differences between physicians' ratings of patients' distress and patients' self-reported distress. Communication skills were analyzed according to the Cancer Research Campaign Workshop Evaluation Manual. RESULTS. Fifty-eight physicians were evaluable. Repeated -measures analysis of variance showed no statistically significant changes over time and between groups in physicians' ability to assess patient distress. Mixed-effects modeling showed that physicians' detection of patients' distress was associated negatively with patients' educational level (P = 0.042) and with patients' self-reported distress (P < 0.000). Mixed-effects modeling also showed that physicians' detection of patient distress was associated positively with physicians breaking bad news (P = 0.022) and using assessment skills (P = 0.015) and supportive skills (P = 0.045). CONCLUSIONS. Contrary to what was expected, no change was observed in physicians' ability to detect distress in patients with cancer after a communication skills training programs, regardless of whether physicians attended the basic training program or the basic training program followed by the consolidation workshops. The results indicated a need for further improvements in physicians' detection skills through specific training modules, including theoretical information about factors that interfere with physicians' detection and through role-playing exercises that focus on assessment and supportive skills that facilitate detection. (c) 2005 American Cancer Society. [less ▲]

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See detailBulletin agrométéorologique - Juin 2005
Tychon, Bernard ULg; Ozer, Pierre ULg; De Longueville, Florence ULg et al

in Bulletin Agrométéorologique (2005), 4(3), 6

Tous les paramètres climatiques furent anormaux à exceptionnels par rapport à la moyenne durant le mois de juin. Aussi, les prévisions de rendements de principales cultures sont globalement à la baisse ... [more ▼]

Tous les paramètres climatiques furent anormaux à exceptionnels par rapport à la moyenne durant le mois de juin. Aussi, les prévisions de rendements de principales cultures sont globalement à la baisse sur le territoire. [less ▲]

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See detailLe G8 ou la Guerre des Mondes
Ozer, Pierre ULg; Balthasar, Jean Pierre

Article for general public (2005)

Les inconditionnels de Steven Spielberg, les passionnés de science fiction et les fans de Tom Cruise comptent les minutes. C'est ce mercredi que sort dans les salles obscures le très attendu « La Guerre ... [more ▼]

Les inconditionnels de Steven Spielberg, les passionnés de science fiction et les fans de Tom Cruise comptent les minutes. C'est ce mercredi que sort dans les salles obscures le très attendu « La Guerre des Mondes » dont les affiches promotionnelles tapissent nos villes depuis deux semaines déjà. La bande annonce nous met en appétit : « Préparez-vous pour un événement qui va changer le monde ». [...] [less ▲]

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See detailRôle des protéinases et de leurs inhibiteurs dans les formes associées à une néovascularisation anormale sous-rétinienne. Caractérisation par l’étude de modèles animaux transgéniques et développements thérapeutiques.
Lambert, Vincent ULg

Doctoral thesis (2005)

La dégénérescence maculaire liée à l'âge (DMLA) est la principale cause de perte visuelle chez les personnes de plus de 70 ans dans le monde occidental. Cette cécité résulte de la perte de fonction de la ... [more ▼]

La dégénérescence maculaire liée à l'âge (DMLA) est la principale cause de perte visuelle chez les personnes de plus de 70 ans dans le monde occidental. Cette cécité résulte de la perte de fonction de la macula (au centre de la rétine) qui est responsable de la vision centrale. Cette dégénérescence réprésente un handicap social indéniable et une perte de liberté pour ces personnes atteintes, car elle affecte des activités telles que la conduite, la lecture ou tout simplement la reconnaissance d’un visage. La pathogénie de cette affection est complexe et peu comprise. La forme la plus grave de cette maladie est associée à une poussée vasculaire (angiogenèse) vers l'espace sous-rétinien qui entraîne une fibrose avec perte des photorécepteurs. La plupart des lésions ne sont pas curables par photocoagulation laser et les stratégies thérapeutiques actuelles sont insuffisantes. Nous avons étudié, dans notre laboratoire, les mécanismes moléculaires de l’angiogenèse. Ce processus invasif requiert la digestion de la matrice extracellulaire avant la prolifération et la migration des capillaires. Deux systèmes enzymatiques sont principalement impliqués dans la digestion tissulaire : le système plasminogène/plasmine et les métalloprotéinases matricielles (MMPs). 1) Le système protéolytique activateur du plasminogène/plasmine : Afin d'évaluer la pertinence biologique de ce système dans l'angiogenèse sous-rétinienne, nous avons mis au point un modèle de néovascularisation choroidienne à l'aide d'un impact laser à l'argon chez des souris déficientes pour une série de gènes fondamentaux de ce système, comparées à des souris normales. Nos observations mettent en évidence le rôle essentiel du PAI-1 dans la néovascularisation sous-rétinienne et contribuent à expliquer l'aspect multifonctionnel du PAI-1 dans l'angiogenèse. 2) Les métalloprotéinases matricielles (MMPs) : Les métalloprotéinases matricielles (MMPs) participent au remodelage normal tissulaire et sont impliquées dans un large éventail de phénomènes physiologiques et pathologiques, tels que l'invasion cellulaire tumorale, la cicatrisation et l'angiogenèse. Nous avons appliqué notre modèle expérimental à des souris déficientes pour deux types de MMP (MMP-2 et MMP-9). La déficience en MMP-2 et -9 inhibe la néovascularisation sous-rétinienne induite par laser, soulignant l’importance de cette enzyme in vivo. Ces études laissent entrevoir des perspectives thérapeutiques dans la lutte contre la DMLA par l’utilisation d’inhibiteur spécifiques des ces MMPs. En conclusion, ces différents aspects de notre étude ouvrent des perpectives de développements thérapeutiques. Ils démontrent l’importance des MMP-2, MMP-9 et de PAI-1 dans la néovascularisation sous-rétinienne. L’inhibition spécifique de ces enzymes laisse entrevoir des espoirs dans le traitement curatif de la dégénérescence maculaire liée à l’âge. Malheureusement de grandes lacunes existent encore quand aux perturbations métaboliques à l’origine de la DMLA, ce qui est l’objet de cette étude. [less ▲]

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See detailMulti-frequency nonlinear energy transfer from linear oscillators to mdof essentially nonlinear attachments
Tsakirtzis, Stylianos; Kerschen, Gaëtan ULg; Panagopoulos, Panagiotis et al

in Journal of Sound & Vibration (2005), 285(1-2), 483-490

We report on multi-frequency energy transfer from a two-mode, initially excited linear system to a multi-degree-of-freedom (mdof) essentially nonlinear attachment. This occurs through simultaneous ... [more ▼]

We report on multi-frequency energy transfer from a two-mode, initially excited linear system to a multi-degree-of-freedom (mdof) essentially nonlinear attachment. This occurs through simultaneous resonance interactions of both linear modes with a set of nonlinear normal modes (NNMs) of the attachment, and is studied utilizing numerical wavelet transforms. The multi-frequency nonlinear energy transfer discussed herein differs from multi-frequency energy transfer caused by resonance capture cascading where sequential energy transfer from a set of linear modes to single-dof nonlinear attachments takes place. (c) 2004 Elsevier Ltd. All rights reserved. [less ▲]

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See detailEtude du classement par forêts aléatoires d'échantillons perturbés à forte structure d'interaction
Brostaux, Yves ULg

Doctoral thesis (2005)

Amongst classification methods, forests of decision trees (Random Forests, BREIMAN, 2001) are highly versatile concerning descriptive attributes' or target variable's nature and shape of the concept to ... [more ▼]

Amongst classification methods, forests of decision trees (Random Forests, BREIMAN, 2001) are highly versatile concerning descriptive attributes' or target variable's nature and shape of the concept to estimate. Their diffusion in agronomical sciences is slowed by a lack of information about their ability to learn models with high interaction structures using learning samples with few examples and affected by random noise and irrelevant attributes. This research aim to fill this gap by a systematic exploration of those factors' effects and of the parameters of the Random Forests method, which is done by computer simulations, taking as a reference the classification trees generated by Breiman's CART method (1984). Results show that generating random forests with a partially deterministic attributes selection and a forest size of at least 100 or 500 trees give the best prediction accuracy. Those random forests show a significant increase in prediction accuracy on CART trees, even for low learning sample size (50 examples). This advantage reduce with the global perturbation level (noise and irrelevant attributes) but increase with the learning sample size, as random forests aren't affected by the asymptotic limitation of the learning curve showed by CART method. [less ▲]

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See detailLiving radical polymerization under emulsion conditions
Szkurhan, K.; Chan-Seng, D.; Kasahara, T. et al

Poster (2005, July 03)

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See detailComet C/2005 K2 (LINEAR)
Jehin, Emmanuel ULg; Nielsen, O.; Bryssinck, E.

in International Astronomical Union Circulars [=IAUCs] (2005), 8566

IAUC 8566 available at Central Bureau for Astronomical Telegrams.

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See detailYin Yang 1 cooperates with activator protein 2 to stimulate ERBB2 gene expression in mammary cancer cells.
Begon, Dominique ULg; Delacroix, Laurence ULg; Vernimmen, Douglas et al

in Journal of Biological Chemistry (2005), 280(26), 24428-34

Overexpression of the ERBB2 oncogene is observed in about 30% of breast cancers and is generally correlated with a poor prognosis. Previous results from our and other laboratories indicated that elevated ... [more ▼]

Overexpression of the ERBB2 oncogene is observed in about 30% of breast cancers and is generally correlated with a poor prognosis. Previous results from our and other laboratories indicated that elevated transcriptional activity contributes significantly to the overexpression of ERBB2 mRNA in mammary adenocarcinoma cell lines. Activator protein 2 (AP-2) transcription factors account for this overexpression through two recognition sequences located 215 and 500 bp upstream from the transcription start site. Furthermore, AP-2 transcription factors are highly expressed in cancer cell lines overexpressing ERBB2. In this report, we examined the cooperative effect of Yin Yang 1 (YY1) on AP-2-induced activation of ERBB2 promoter activity. We detected high levels of YY1 transcription factor in mammary cancer cell lines. Notably, we showed that YY1 enhances AP-2alpha transcriptional activation of the ERBB2 promoter through an AP-2 site both in HepG2 and in HCT116 cells, whereas a carboxyl-terminal-truncated form of YY1 cannot. Moreover, we demonstrated the interaction between endogenous AP-2 and YY1 factors in the BT-474 mammary adenocarcinoma cell line. In addition, inhibition of endogenous YY1 protein by an antisense decreased the transcription of an AP-2-responsive ERBB2 reporter plasmid in BT-474 breast cancer cells. Finally, we detected in vivo AP-2 and YY1 occupancy of the ERBB2 proximal promoter in chromatin immunoprecipitation assays. Our data thus provide evidence that YY1 cooperates with AP-2 to stimulate ERBB2 promoter activity through the AP-2 binding sites. [less ▲]

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