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See detailOnline least-squares policy iteration for reinforcement learning control
Busoniu, Lucian; Ernst, Damien ULg; De Schutter, Bart et al

in Proceedings of the 2010 American Control Conference (2010)

Reinforcement learning is a promising paradigm for learning optimal control. We consider policy iteration (PI) algorithms for reinforcement learning, which iteratively evaluate and improve control ... [more ▼]

Reinforcement learning is a promising paradigm for learning optimal control. We consider policy iteration (PI) algorithms for reinforcement learning, which iteratively evaluate and improve control policies. State-of-the-art, least-squares techniques for policy evaluation are sample-efficient and have relaxed convergence requirements. However, they are typically used in offline PI, whereas a central goal of reinforcement learning is to develop online algorithms. Therefore, we propose an online PI algorithm that evaluates policies with the so-called least-squares temporal difference for Q-functions (LSTD-Q). The crucial difference between this online least-squares policy iteration (LSPI) algorithm and its offline counterpart is that, in the online case, policy improvements must be performed once every few state transitions, using only an incomplete evaluation of the current policy. In an extensive experimental evaluation, online LSPI is found to work well for a wide range of its parameters, and to learn successfully in a real-time example. Online LSPI also compares favorably with offline LSPI and with a different flavor of online PI, which instead of LSTD-Q employs another least-squares method for policy evaluation. [less ▲]

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See detailLa vignette thérapeutiqu de l'étudiant Diagnostic différentiel étiologique des oedmes
Krzesinski, Jean-Marie ULg

in Revue Médicale de Liège (2010), 65(11), 655-661

Oedema is a frequent disorder and the easily detectable consequence of an increase of fluid located in the interstitial tissue. It could be localized or generalized and related either to a primary ... [more ▼]

Oedema is a frequent disorder and the easily detectable consequence of an increase of fluid located in the interstitial tissue. It could be localized or generalized and related either to a primary disturbance of hemodynamics at the capillary level, due to a modification of the Starling’s law components with secondary water and saline retention, or to a primary retention of salt and water linked to a kidney abnormality. Generalized forms are pitting oedema, most often painless, white, bilateral and symmetric, distributed at the lower part of the body (localisation according to the gravitation law). They are different in their characteristics from localized oedema or lymphoedema which are tough. We propose a diagnostic approach based on medical history, clinical examination which allows a confident medical diagnosis and so an adapted therapy. [less ▲]

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See detailAb initio calculation of H + He+ charge-transfer cross section for plasma physics
Loreau, Jérôme; Sodoga, Komi; Lauvergnat, David et al

in Physical Review. A (2010), 82

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See detailAssessing the Impact of Weather on Traffic Intensity
Cools, Mario ULg; Moons, Elke; Wets, Geert

in Weather, Climate and Society (2010), 2(1), 6068

This paper focuses on the effect of weather conditions on daily traffic intensities (the number of cars passing a specific segment of a road). The main objective is to examination whether or not weather ... [more ▼]

This paper focuses on the effect of weather conditions on daily traffic intensities (the number of cars passing a specific segment of a road). The main objective is to examination whether or not weather conditions uniformly alter daily traffic intensities in Belgium, or in other words whether or not road usage on a particular location determines the size of the impacts of various weather conditions. This general examination is a contribution that allows policymakers to assess the appropriateness of countrywide versus local traffic management strategies. In addition, a secondary goal of this paper is to validate findings in international literature within a Belgian context. To achieve these goals, the paper analyzes the effects of weather conditions on both upstream (toward a specific location) and downstream (away from a specific location) traffic intensities at three traffic count locations typified by a different road usage. Perhaps the most interesting results of this study for policymakers are the heterogeneity of the weather effects between different traffic count locations, and the homogeneity of the weather effects on upstream and downstream traffic at specific locations. The results also indicate that snowfall, rainfall, and wind speed diminish traffic intensity, and high temperatures increase traffic intensity. Further generalizations of the findings might be possible by studying weather impacts on local roads and by shifting the focus of research toward travel behavior. [less ▲]

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See detailEthique de l’information clinique et consentement des patients
Jamoulle, Marc ULg

Report (2010)

Le projet de recherche REGM (Enregistrement de morbidité) du Service Public Fédéral Belge de la Santé Publique (SPF-SP) se propose d’étudier la faisabilité de la constitution de base de données de ... [more ▼]

Le projet de recherche REGM (Enregistrement de morbidité) du Service Public Fédéral Belge de la Santé Publique (SPF-SP) se propose d’étudier la faisabilité de la constitution de base de données de morbidité en médecine générale en Belgique. Dans ce cadre la question du consentement des patients (et des médecins) est bien sur centrale et préalable à tous développements ultérieurs. On examine ici les conditions de réalisations d’un tel consentement du patient et les différentes formes qu’il peut prendre. Des expériences sont relatées qui permettent de prendre la mesure des enjeux. Une recommandation est formulée pour un consentement différencié, distinct et dynamique qui se fait l’écho de la relation de confiance médecin patient dont il est la traduction. [less ▲]

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See detailCortisol awakening response (CAR)’s flexibility leads to larger and more consistent associations with psychological factors than CAR magnitude
Mikolajczak, M.; Quoidbach, Jordi ULg; Vanootighem, Valentine ULg et al

in Psychoneuroendocrinology (2010)

The cortisol awakening response (CAR) is increasingly recognized as a potential biological marker of psychological and physical health status. Yet, the CAR literature is replete with contradictory results ... [more ▼]

The cortisol awakening response (CAR) is increasingly recognized as a potential biological marker of psychological and physical health status. Yet, the CAR literature is replete with contradictory results: both supposedly protective and vulnerability psychosocial factors have been associated with both increased and decreased CAR. In this study, we tested the hypothesis that the CAR flexibility would be a better indicator of psychological status than CAR magnitude. Forty-two men measures of happiness, perceived stress and neuroticism, and took saliva samples immediately on awakening, then at 15, 30, 45 and 60 min post-awakening on three study days (i.e., Sunday, Monday and Tuesday). When considering the CAR magnitude, our effects perfectly reflect the inconsistencies previously observed in the literature (i.e., the main effects of the psychological predictors are not consistent with each other, and the effect of one predictor on a given day contradicts the effect of the same predictor on another day). However, considering the CAR flexibility leads to a fully consistent pattern: protective factors (i.e., high happiness, low stress, low neurotiscim) are associated with a flexible CAR (i.e., lower CAR during weekends compared to workdays) whereas vulnerability factors (i.e., low happiness, high stress, high neurotiscim) are associated with a stiff CAR (i.e., same magnitude during weekends and workdays). We conclude that considering the CAR flexibility (e.g., between weekends and workdays) rather than the traditional CAR magnitude might be a way to understand the apparent conflicts in the CAR literature. [less ▲]

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See detailCrown rot of banana: Preharvest factors involved in postharvest disease development and integrated control methods
Lassois, Ludivine ULg; Jijakli, Haissam ULg; Chillet, M. et al

in Plant Disease (2010), 94(6), 648-658

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See detailOn the Sets of Real Numbers Recognized by Finite Automata in Multiple Bases
Boigelot, Bernard ULg; Brusten, Julien ULg; Bruyère, Véronique

in Logical Methods in Computer Science (2010), 6(1), 1-17

This article studies the expressive power of finite automata recognizing sets of real numbers encoded in positional notation. We consider Muller automata as well as the restricted class of weak ... [more ▼]

This article studies the expressive power of finite automata recognizing sets of real numbers encoded in positional notation. We consider Muller automata as well as the restricted class of weak deterministic automata, used as symbolic set representations in actual applications. In previous work, it has been established that the sets of numbers that are recognizable by weak deterministic automata in two bases that do not share the same set of prime factors are exactly those that are definable in the first order additive theory of real and integer numbers. This result extends Cobham's theorem, which characterizes the sets of integer numbers that are recognizable by finite automata in multiple bases. In this article, we first generalize this result to multiplicatively independent bases, which brings it closer to the original statement of Cobham's theorem. Then, we study the sets of reals recognizable by Muller automata in two bases. We show with a counterexample that, in this setting, Cobham's theorem does not generalize to multiplicatively independent bases. Finally, we prove that the sets of reals that are recognizable by Muller automata in two bases that do not share the same set of prime factors are exactly those definable in the first order additive theory of real and integer numbers. These sets are thus also recognizable by weak deterministic automata. This result leads to a precise characterization of the sets of real numbers that are recognizable in multiple bases, and provides a theoretical justification to the use of weak automata as symbolic representations of sets. [less ▲]

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See detailImplicit Real Vector Automata
Boigelot, Bernard ULg; Brusten, Julien ULg; Degbomont, Jean-François ULg

in Electronic Proceedings in Theoretical Computer Science (2010), 39

This paper addresses the symbolic representation of non-convex real polyhedra, i.e., sets of real vectors satisfying arbitrary Boolean combinations of linear constraints. We develop an original data ... [more ▼]

This paper addresses the symbolic representation of non-convex real polyhedra, i.e., sets of real vectors satisfying arbitrary Boolean combinations of linear constraints. We develop an original data structure for representing such sets, based on an implicit and concise encoding of a known structure, the Real Vector Automaton. The resulting formalism provides a canonical representation of polyhedra, is closed under Boolean operators, and admits an efficient decision procedure for testing the membership of a vector. [less ▲]

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See detailSemantic Hyperpriming in Normal Aging: A Consequence of Instructions?
Stefaniak, Nicolas ULg; Meulemans, Thierry ULg; Willems, Sylvie ULg

in Neuropsychology, Development, and Cognition. Section B, Aging, Neuropsychology and Cognition (2010), 17(5), 615-632

Semantic hyperpriming has consistently been found in normal aging. However, <br />because the standard instructions to test semantic priming are generally ambiguous <br />(focusing on both accuracy and ... [more ▼]

Semantic hyperpriming has consistently been found in normal aging. However, <br />because the standard instructions to test semantic priming are generally ambiguous <br />(focusing on both accuracy and speed), it is difficult to account for hyperpriming in <br />older adults. By using the direct and mediated priming paradigms, this study investigates <br />whether older adults’ response mode at testing may explain hyperpriming. First, we <br />show that, under identical conditions, inducing a response mode that favors speed leads <br />to greater priming effects in older adults. The pattern of results is similar to what is <br />observed under standard instructions. Second, prompting a response mode that favors <br />accuracy leads to greater priming effects in younger adults. We discuss various explanations <br />for these findings and conclude, in accordance with the Ratcliff, Thapar, <br />Gomez, and McKoon (2004a) diffusion model, that hyperpriming in normal aging is <br />contingent on older adults’ response mode at testing. [less ▲]

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See detailIntegrated control of crown rot of banana with Candida oleophila strain O, calcium chloride and modified atmosphere packaging
Bastiaanse, H.; de Lapeyre de Bellaire, Luc; Lassois, Ludivine ULg et al

in Biological Control (2010), 53

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See detailSoluble forms of VEGF receptor-1 and -2 promote vascular maturation via mural cell recruitment.
LORQUET, Sophie ULg; Berndt, Sarah; Blacher, Silvia ULg et al

in FASEB Journal (2010), 24(10), 3782-95

Two soluble forms of vascular endothelial growth factor (VEGF) receptors, sVEGFR-1 and sVEGFR-2, are physiologically released and overproduced in some pathologies. They are known to act as anti-VEGF ... [more ▼]

Two soluble forms of vascular endothelial growth factor (VEGF) receptors, sVEGFR-1 and sVEGFR-2, are physiologically released and overproduced in some pathologies. They are known to act as anti-VEGF agents. Here, we report that these soluble receptors contribute to vessel maturation by mediating a dialogue between endothelial cells (EC) and mural cells that leads to blood vessel stabilization. Through a multidisciplinary approach, we provide evidences that these soluble VEGF receptors promote mural cell migration through a paracrine mechanism involving interplay in EC between VEGF/VEGFR-2 and sphingosine-1- phosphate type-1 (S1P)/S1P1 pathways that leads to endothelial nitric oxyde synthase (eNOS) activation. This new paradigm is supported by the finding that sVEGFR-1 and -2: 1) induce an eNOS-dependent outgrowth of a mural cell network in an ex vivo model of angiogenesis, 2) increase the mural cell coverage of neovessels in vitro and in vivo, 3) promote mural cell migration towards EC, 4) stimulate endothelial S1P1 overproduction and eNOS activation that promote the migration and the recruitment of neighboring mural cells. These findings provide new insights into mechanisms regulating physiological and pathological angiogenesis and vessel stabilization. [less ▲]

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See detailReliable hydraulic numerical modeling with multiblock grids and linked models
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Proc. Int. Conf. SimHydro 2010: Hydraulic modeling and uncertainty (2010)

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See detailContribution théorique et numérique a la modélisation des écoulements mixtes diphasiques hautement transitoires
Kerger, François ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Proc. Int. Conf. SimHydro 2010: Hydraulic modeling and uncertainty (2010)

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See detailSHIP-1 inhibits CD95/APO-1/Fas-induced apoptosis in primary T lymphocytes and T leukemic cells by promoting CD95 glycosylation independently of its phosphatase activity
Charlier, Edith ULg; Condé, Claude ULg; Zhang, Jing et al

in Leukemia : Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K (2010)

SHIP-1 functions as a negative regulator of immune responses by hydrolyzing phosphatidylinositol-3,4,5-triphosphate generated by PI 3-kinase activity. As a result, SHIP-1 deficiency in mice results in ... [more ▼]

SHIP-1 functions as a negative regulator of immune responses by hydrolyzing phosphatidylinositol-3,4,5-triphosphate generated by PI 3-kinase activity. As a result, SHIP-1 deficiency in mice results in myeloproliferation and B cell lymphoma. On the other hand, SHIP-1 deficient mice have a reduced T cell population, but the underlying mechanisms are unknown. In this work, we hypothesized that SHIP-1 plays anti-apoptotic functions in T cells upon stimulation of the death receptor CD95/APO-1/Fas. Using primary T cells from SHIP-1-/- mice and T leukemic cell lines, we report here that SHIP-1 is a potent inhibitor of CD95-induced death. We observed that a small fraction of the SHIP-1 pool is localized to the endoplasmic reticulum where it promotes CD95 glycosylation. This post-translational modification requires an intact SH2 domain of SHIP-1, but is independent of its phosphatase activity. The glycosylated CD95 fails to oligomerize upon stimulation, resulting in impaired DISC formation and downstream apoptotic cascade. These results uncover an unanticipated inhibitory function for SHIP-1 and emphasize the role of glycosylation in the regulation of CD95 signaling in T cells. This work may also provide a new basis for therapeutic strategies using compounds inducing apoptosis through the CD95 pathway on SHIP-1 negative leukemic T cells. [less ▲]

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See detailChapter 6 : Agrometeorological forecasting
Gommes, René; Das, Haripada; Mariani, Luigi et al

in WMO/CAgM Guide to Agricultural Meteorological Practices (GAMP) WMO n° 134 (2010)

This chapter presents a set of tools and techniques for crop yield forecasting.

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See detailNational Forest Inventories Pathways for Common Reporting: Belgium (Walloon Region)
Rondeux, Jacques ULg; Sanchez, Christine; Latte, Nicolas ULg

in Tomppo, Erkki; Gschwantner, Thomas; Lawrence, Mark (Eds.) et al National Forest Inventories. Pathways for Common Reporting (2010)

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See detailModave/Modave : elements du Mésolithique recent de la couche 4b-delta du Trou Al'Wesse
Miller, Rebecca ULg; Otte, Marcel ULg; Stewart, John

in Chronique de l'Archéologie Wallonne (2010), 17

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See detailEffect of exogenous circulating anti-bPL antibodies on bovine placental lactogen measurements in foetal samples.
Alvarez Oxiley, Andrea Vivian ULg; Melo de Sousa, Noelita ULg; Hornick, Jean-Luc ULg et al

in Acta Veterinaria Scandinavica (2010), 52

BACKGROUND: The involvement of placental lactogen (PL) in the regulation of foetal growth has been investigated in different species by in vivo immunomodulation techniques. However, when circulating ... [more ▼]

BACKGROUND: The involvement of placental lactogen (PL) in the regulation of foetal growth has been investigated in different species by in vivo immunomodulation techniques. However, when circulating antibodies are present together with the hormone, the procedure for hormonal measurement becomes considerably complex. The aim of this study was the immunoneutralization of bovine placental lactogen (bPL) concentrations in bovine foetal circulation by direct infusion of rabbit anti-bPL purified immunoglobulins (IgG) via a foetal catheter (in vivo study). The ability of a RIA based on guinea pig anti-bPL antiserum, for the measurement of bPL concentrations in samples containing exogenous rabbit anti-bPL immunoglobulins, was also analyzed in in vitro and in vivo conditions. METHODS: Six bovine foetuses were chronic cannulated on the aorta via the medial tarsal artery. Infusion of rabbit anti-bPL IgG was performed during late gestation. Pooled rabbit anti-bPL antisera had a maximal neutralization capacity of 25 microg bPL/mL of immunoglobulin. Interference of rabbit anti-bPL immunoglobulin with radioimmunoassay measurement using guinea pig anti-bPL as primary antibody was first evaluated in vitro. Polyclonal anti-bPL antibodies raised in rabbit were added in foetal sera to produce 100 samples with known antibodies titers (dilutions ranging from 1:2,500 till 1:1,280,000). RESULT(S): Assessment of the interference of rabbit anti-bPL antibody showed that bPL concentrations were significantly lower (P < 0.05) in samples added with dilutions of rabbit antiserum lower than 1:80,000 (one foetus) or 1:10,000 (four foetuses). It was also shown that the recovery of added bPL (12 ng/mL) was markedly reduced in those samples in which exogenous rabbit anti-bPL were added at dilutions lower than 1:20,000. Concentrations of foetal bPL were determined in samples from cannulated foetuses. In foetuses 1 and 6, bPL concentrations remained almost unchanged (<5 ng/mL) during the whole experimental period. In Foetus 3, bPL concentrations decreased immediately after IgG infusion and thereafter, they increased until parturition. CONCLUSION(S): The use of a bPL RIA using a guinea pig anti-bPL as primary antiserum allowed for the measurement of bPL concentrations in foetal plasma in presence of rabbit anti-bPL IgG into the foetal circulation. Long-term foetal catheterization allowed for the study of the influence of direct infusion of anti-bPL IgG on peripheral bPL concentrations in bovine foetuses. [less ▲]

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See detailContractile reserve assessed using dobutamine echocardiography predicts left ventricular reverse remodeling after cardiac resynchronization therapy: prospective validation in patients with left ventricular dyssynchrony.
Sénéchal, Mario; Lancellotti, Patrizio ULg; Magne, Julien ULg et al

in Echocardiography (2010), 27(6), 668-76

Background: The presence of viable myocardium may predict response to cardiac resynchronization therapy (CRT). The aim of this study is to evaluate in patients with left ventricular (LV) dyssynchrony ... [more ▼]

Background: The presence of viable myocardium may predict response to cardiac resynchronization therapy (CRT). The aim of this study is to evaluate in patients with left ventricular (LV) dyssynchrony whether response to CRT is related to myocardial viability in the region of the pacing lead. Methods: Forty-nine consecutive patients with advanced heart failure, LV ejection fraction < 35%, QRS duration > 120 ms and intraventricular asynchronism ≥ 50 ms were included. Dobutamine stress echocardiography was performed within the week before CRT implantation. Resting echocardiography was performed 6 months after CRT implantation. Viability in the region of LV pacing lead was defined as the presence of viability in two contiguous segments. Response to CRT was defined by evidence of reverse LV remodeling (≥15% reduction in LV end-systolic volume). Results: Thirty-one patients (63%) were identified as responders at follow-up. The average of viable segments was 5.9 ± 2 in responders and 3.2 ± 3 in nonresponders (P = 0.0003). Viability in the region of the pacing lead had a sensitivity of 94%, a specificity of 67%, a positive predictive value of 83%, and a negative predictive value of 86% for the prediction of response to CRT. Conclusions: In patients with LV dyssynchrony, reverse remodeling after CRT requires viability in the region of the pacing lead. This simple method using echocardiography dobutamine for the evaluation of local viability (i.e., viability in two contiguous segments) may be useful to the clinician in choosing the best LV lead positioning. [less ▲]

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