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See detailWhen children stop trusting what they have perceived
Geurten, Marie ULg; Willems, Sylvie; Meulemans, Thierry ULg

in Neuropsychological Rehabilitation Special Interest Group of the WFNR - Conference Programme (2014, July)

Background and aims: A common hypothesis to explain metamemory heuristics learning throughout childhood lies on the assumption that the knowledge underlying these metacognitive rules develop from people’s ... [more ▼]

Background and aims: A common hypothesis to explain metamemory heuristics learning throughout childhood lies on the assumption that the knowledge underlying these metacognitive rules develop from people’s prior day-to-day experiences. However, the specific processes that sustain this learning are still unclear. In this study, we examined the mechanisms implicated in this empirical development by manipulating the learned interpretation of the Easily Learned = Easily Remembered (ELER) heuristic through an implicit process involving the detection of environmental regularities. Method: A sample of sixty normally developing children aged 4-5, 6-7, and 8-9 years old was recruited for this study. Each child participated in three 60-minute sessions separated approximately by one-week interval and was trained to learn implicitly a reverse interpretation of the ELER heuristic. The influence of executive functions on children’s judgment of learning at posttest was also investigated. Results: In addition to an early development of the ELER heuristic, results revealed a reduction of this heuristic’s use after the implicit training in the two youngest groups. Furthermore, executive monitoring was demonstrated to account for the lack of change observed in older children after the training phases. Conclusions: In a developmental perspective, these findings present a coherent picture of children’s learning of metacognitive heuristics. Specifically, automatic and implicit learning was demonstrated to be followed by an effortful control of the heuristics’ use. [less ▲]

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See detailDroplet synchronization in multiple interconnected parallel channels
Van Loo, Stéphanie ULg; Stoukatch, Serguei ULg; Gilet, Tristan ULg

Poster (2014, July)

In droplet microfluidics, the pairing of droplets in parallel channels is sometimes required, e.g. to control their encounter and to promote their coalescence. Prakash and Gershenfeld [1] showed that ... [more ▼]

In droplet microfluidics, the pairing of droplets in parallel channels is sometimes required, e.g. to control their encounter and to promote their coalescence. Prakash and Gershenfeld [1] showed that passive synchronization could be achieved with bubbles in a ladder-like channel network. Bubbles flow in the rails and induce recirculation in the interconnecting rungs, which supposedly provides the feedback and subsequent synchronization. Ahn et al. recently extended this study to trains of droplets in flow-rate-driven conditions [2]. We here present an extensive experimental and theoretical investigation of droplets synchonization in multiple parallel channels. Droplets are produced with independent flow-focusing structures. Several experimental conditions are tested, including several geometries (and subsequent flow resistance) and inlet conditions (pressure-driven vs. flow-rate-driven). An extension to three rails is also considered. The microfluidic chips are designed with the help of a lumped-element model in which droplets are driven by the flows. [1] M. Prakash and N. Gershenfeld, Science 2007, 315, 832-835 [2] Ahn et al., Lab-on-a-chip, 2011, 11, 3956-3962 [less ▲]

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See detail« Sémiotique de l’action : textualisation et notation »
Dondero, Maria Giulia ULg

in CASA - Cadernos de Semiótica Aplicada (2014), 12(1), 15-57

Our essay focuses on some methodological issues concerning the semiotic analysis of practice. We will initially retrace the debate about the epistemological relationship between text and action, outlining ... [more ▼]

Our essay focuses on some methodological issues concerning the semiotic analysis of practice. We will initially retrace the debate about the epistemological relationship between text and action, outlining the forms of enunciative praxis through different levels of pertinence analysis. Secondly, we propose the concept of ‘textualization’ as a mediation between text and action: textualizations (photographs, videos, notes) organize and represent practices which are in themselves ephemeral and elusive. Finally, we will consider the textual diagrammatization that we call ‘notation’: this analytical form of mediation between text and practice does not have the same status of in-vivo textualisations, but it works like an ex-post reconstruction which highlights the main gestures and exchanges while performing their grammaticalization. A more general aim of this essay is an enquiry into the legitimate objects of textual semiotics: what are the objects that it can analyze without betraying its principle of immanence, but also without being confined to it and, as a consequence, being unable to analyze practices and respond to topical questions on social issues and on the research in the human sciences? [less ▲]

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See detailMathematical modeling of HIV dynamics after antiretroviral therapy initiation: A clinical research
Moog, Claude; Rivadeneira, Pablo; Stan, Guy-Bart et al

in AIDS Research and Human Retroviruses (2014)

Immunological failure is identified from the estimation of certain parameters of a mathematical model of the HIV infection dynamics. This identification is supported by clinical research results from an ... [more ▼]

Immunological failure is identified from the estimation of certain parameters of a mathematical model of the HIV infection dynamics. This identification is supported by clinical research results from an original clinical trial. Standard clinical data were collected from infected patients starting Highly Active Anti-Retroviral Therapy (HAART), just after one month following therapy initiation and were used to carry out the model identification. The early diagnosis is shown to be consistent with the patients monitoring after six months. [less ▲]

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See detailThe puzzling new class of variable stars in NGC 3766 : old friend pulsators?
Salmon, Sébastien ULg; Montalban Iglesias, Josefa ULg; Reese, Daniel et al

in Astronomy and Astrophysics (2014)

The recent variability survey of the NGC 3766 cluster revealed a considerable number of periodic variable stars in a region of the H-R diagram where no pulsation is expected. This region lies between the ... [more ▼]

The recent variability survey of the NGC 3766 cluster revealed a considerable number of periodic variable stars in a region of the H-R diagram where no pulsation is expected. This region lies between the instability strips of the delta Scuti and SPB stars. Moreover the periods of the new phenomenon, P~0.1-0.7 d, do not allow to associate it a priori to either of these two types of pulsations. Stars in the NGC 3766 cluster are known as fast rotators with rotational velocities typically larger than half of their critical velocity. Rotation can affect both the geometrical properties and period domain of pulsations. It also alters the apparent stellar luminosity through gravity darkening, effect seldom taken considered in theoretical studies of the rotation-pulsation interaction. We explore if both of these effects are able to deliver a consistent interpretation for the observed properties of the "new variables" in NGC 3766: explaining their presence outside the known instability strips and their variability periods. We carry out an instability analysis of SPB models within the framework of the Traditional Approximation of Rotation and study the visibility of modes according to the angle of view and rotation. We also check how gravity darkening affects the effective temperature and luminosity of stellar models for different angles of view and rotation velocities. At the red (cold) border of the instability strip, prograde sectoral modes are preferentially excited and their visibilities are maximum when seen equator-on. Furthermore low-mass SPB models seen equator-on can appear in the gap between non-rotating SPB and delta Scuti stars due to gravity darkening. In that case, periods of these most visible modes are shifted to the 0.2-0.5 d range due to the effects of the Coriolis force. We hence suggest that the new variable stars observed in NGC 3766 are actually fast rotating SPB pulsators. [less ▲]

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See detailTHE NORDIC TEST SYSTEM FOR VOLTAGE STABILITY ASSESSMENT
Van Cutsem, Thierry ULg

Conference (2014, July)

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See detailEarly Prediction of Transient Voltage Sags caused by Rotor Swings
Weckesser, Tilman; Johannsson, Hjortur; Van Cutsem, Thierry ULg

in Proc. IEEE PES general meeting (2014, July)

The paper investigates various methods to predict voltage sags at load buses caused by large generator rotor swings and following a transient disturbance. Three different prediction methods are proposed ... [more ▼]

The paper investigates various methods to predict voltage sags at load buses caused by large generator rotor swings and following a transient disturbance. Three different prediction methods are proposed, which all use real-time measurements from PMUs. One of the methods uses a slightly extended version of the E-SIME method. The other two methods use measurements and process them by recursive least square estimation. It is shown that the prediction method employing E-SIME allows the earliest detection of a critical voltage sag with satisfactory accuracy. [less ▲]

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See detailLe regard cosmopolite et rétrospectif de la bande dessinée alternative
Dejasse, Erwin ULg

in Dony, Christophe; Habrand, Tanguy; Meesters, Gert (Eds.) La bande dessinée en dissidence / Comics in Dissent Alternative, indépendance, auto-édition / Alternative, Independence, Self-Publishing (2014)

When critically exploring alternative comics, the various actors participating in the processes of legitimization of the form — including print and broadcast media, festivals, scholars and fans — often ... [more ▼]

When critically exploring alternative comics, the various actors participating in the processes of legitimization of the form — including print and broadcast media, festivals, scholars and fans — often privilege a handful of people (Sfar, Trondheim, Ware, Satrapi,…), a small number of publishers (especially L’Association), a few particular formats such as the “graphic novel,” emblematic genres (the memoir and autobiography), or certain geographical areas such as France and/or the United States. And yet, the phenomenon of alternative comics may take a multitude of forms and is resolutely international in scope. Despite this diversity, alternative comics worldwide nevertheless share common objectives. They notably include the challenging of two of the most common critical stances directed against a multitude of “traditional” publishers, namely : their inclination towards ethnocentricity and their cultivation of amnesia. Far from sweeping away the history of the form, alternative comics artists and publishers alike attach great value to the past of the medium and generally embrace it. [less ▲]

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See detailOn the convergence of relaxation schemes to couple phasor-mode and electromagnetic transients simulations
Plumier, Frédéric ULg; Geuzaine, Christophe ULg; Van Cutsem, Thierry ULg

in Proceedings of the IEEE PES General Meeting (2014, July)

Hybrid simulations combining phasor-mode and electromagnetic transients models aim at taking advantage of computational speed of the former and accuracy of the latter. For simulation accuracy, a ... [more ▼]

Hybrid simulations combining phasor-mode and electromagnetic transients models aim at taking advantage of computational speed of the former and accuracy of the latter. For simulation accuracy, a relaxation process is used, which consists of iterating between both models. The convergence properties of this relaxation process are investigated. The speed of convergence is assessed when the variables exchanged at the interface between both models are respectively pure voltage/current sources, Norton/Thévenin equivalents, or a combination of them. Iteratively updated Norton/Thévenin equivalents are shown to drastically reduce the number of relaxation iterations. [less ▲]

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See detailThe concept of economic security of the hospital: A new look at the levers of control
Shutyak, Yuliya ULg; Van Caillie, Didier ULg

in Forum Scientiae Oeconomia (2014), 2/2

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See detailMultidimensional analysis of the importance given to physical activity promotion in secondary schools of French-speaking Belgium
Snyers, Jérôme; Halkin, Anne-Sophie; Lejacques, Thibaut et al

in Global Journal of Health and Physical Education Pedagogy (2014), 3(3), 212-227

Schools present a privileged environment to address physical inactivity. Actions to promote an active lifestyle have been launched for over 20 years in the European Union. In French-speaking Belgium, such ... [more ▼]

Schools present a privileged environment to address physical inactivity. Actions to promote an active lifestyle have been launched for over 20 years in the European Union. In French-speaking Belgium, such actions have multiplied, but efficiency remains undocumented due to the lack of systematic data regarding health and physical activity (PA) promotion at school. This research aimed to create a tool and to use it to establish an empirical baseline regarding PA promotion in secondary schools. Six main dimensions, all broken into variables, were identified after an extensive literature search. Six experts assigned different weighting factors to each dimension and variable, thereby allowing the attribution of scores. Fifty-one secondary schools were analyzed on this basis. The mean global score of the sample was 44.7 on a maximum of 100. PA was better promoted in urban schools with 250 to 499 students with high socioeconomic status. Real in-school policies aimed at promoting PA were lacking. Active transport to and from school was seldom encouraged. The number of PE classes was insufficient. The facilities used were of better quality than expected. This exploratory research constitutes an important step toward the conception of a tool based solely on objective variables. It should also serve as a catalyst to implement new field projects. [less ▲]

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See detailChina, 1978-2013: from one Plenum to another. Reflections on hopes and constraints for reform in the Xi Jingping era
Florence, Eric ULg

E-print/Working paper (2014)

Why is it so difficult to talk about China in a nuanced and contrasting manner without falling back on superlatives and generalisations? In about thirty years, China’s GDP per capita has multiplied by ... [more ▼]

Why is it so difficult to talk about China in a nuanced and contrasting manner without falling back on superlatives and generalisations? In about thirty years, China’s GDP per capita has multiplied by eight. From a marginal economic power during the Maoist period (1949-1978), China is now ranked tenth in terms of global economic weight. “Wealth and power” (fu qiang) is the expression that embodies China’s quest for modernity since the second half of the 19th century, when China was still under the yoke of the West. This ambition is still at the heart of the “Chinese dream of rejuvenation of the Chinese nation” dear to Xi Jinping, which he set out during the Third Plenum of the 18th Central Committee of the Chinese Communist Party. But focusing only on this vision of “wealth and power” takes us back to one of the most common ways of representing China: reducing the ongoing socio-economic changes and dynamics to a set of numeric values, ultimately reified and homogenised. The increased power and internationalisation of the Chinese economy has prompted a combination of worry and enthusiasm. What does this imply about the paradigm shift in the way we portray this country? Perhaps it is still hard to leave behind the image of a subordinate, poor and voiceless China and consider the Chinese people as, at least, our equals. [less ▲]

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See detailNew Orleans Jazz & Heritage Festival 2014
Sacré, Robert ULg

E-print/Working paper (2014)

Compte rendu du NOLA Jazz & Heritage Festival avril-mai 2014 , avec photos

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See detail3D analysis and determination of stride parameters for different type of foot strike in running
Deflandre, Dorian ULg; Bury, Thierry ULg; Schwartz, Cédric ULg et al

Poster (2014, July)

The purpose of the study was to compare methods for the determination of foot strike and toe off for runners with different foot strike patterns. A 3D optoelectronic system usually used in motion ... [more ▼]

The purpose of the study was to compare methods for the determination of foot strike and toe off for runners with different foot strike patterns. A 3D optoelectronic system usually used in motion laboratories was compared with tools commonly used on the field: an optical based detection system (OptoGait) and an accelerometer based system (Myotest). [less ▲]

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See detailWenn Puppen es machen. Eindrücke von der 11. figuma in Eupen (B)
Wunsch-Viehöver, Vera ULg; Wunsch, Stephan

in Das Andere Theater (2014), 24(85),

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See detailReactor mixing angle from hybrid neutrino masses
Aristizabal Sierra, Diego ULg; de Medeiros Varzielas, Ivo

in Journal of High Energy Physics [=JHEP] (2014), 2014(7),

In terms of its eigenvector decomposition, the neutrino mass matrix (in the basis where the charged lepton mass matrix is diagonal) can be understood as originating from a tribimaximal dominant structure ... [more ▼]

In terms of its eigenvector decomposition, the neutrino mass matrix (in the basis where the charged lepton mass matrix is diagonal) can be understood as originating from a tribimaximal dominant structure with small deviations, as demanded by data. If neutrino masses originate from at least two different mechanisms, referred to as "hybrid neutrino masses", the experimentally observed structure naturally emerges provided one mechanism accounts for the dominant tribimaximal structure while the other is responsible for the deviations. We demonstrate the feasibility of this picture in a fairly model-independent way by using lepton-number-violating effective operators, whose structure we assume becomes dictated by an underlying A4 flavor symmetry. We show that if a second mechanism is at work, the requirement of generating a reactor angle within its experimental range always fixes the solar and atmospheric angles in agreement with data, in contrast to the case where the deviations are induced by next-to-leading order effective operators. We prove this idea is viable by constructing an A4-based ultraviolet completion, where the dominant tribimaximal structure arises from the type-I seesaw while the subleading contribution is determined by either type-II or type-III seesaw driven by a non-trivial A4 singlet (minimal hybrid model). After finding general criteria, we identify all the ZN symmetries capable of producing such A4-based minimal hybrid models. [less ▲]

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See detailHigh throughput sequencing analysis reveals genetic variability and selection pressure in different murine norovirus genomic regions during in vitro replication
Mauroy, Axel ULg; Taminiau, Bernard ULg; Nezer, Carine et al

Poster (2014, July)

Murine norovirus (MuNoV), a single stranded positive sense RNA virus belonging to the Caliciviridae family, is considered as a representative model for human norovirus infections, one of the most ... [more ▼]

Murine norovirus (MuNoV), a single stranded positive sense RNA virus belonging to the Caliciviridae family, is considered as a representative model for human norovirus infections, one of the most important etiological cause of both epidemic and sporadic gastroenteritis cases worldwide. Four open reading frames are described into its genome: ORF1 codes the non-structural (NS) proteins, including the viral RNA dependent RNA polymerase (RdRp); ORF2 codes the single capsid protein (VP1), wherein two domains are present: a relatively conserved domain (“shell”) and a more variable domain (“protruding”); ORF3 codes a minor structural protein; and ORF4, currently only found in viruses genetically related to MuNoV codes a virulence factor. In this study, we demonstrated by high throughput sequencing that, during serial passages of MuNoV in cell culture, the substitution rates, estimated by Bayesian inferences, did not significantly differ across the five targeted genomic regions except one. These rates were similar in four genomic regions encompassing partial non-structural 1-2 protein (NS1-2)-, NS5-, NS6-, NS7 (RdRp)- and VP1-coding sequences (coding the conserved part of the protein also including the ORF4 region). In the partial minor structural protein-coding region, this substitution rate was however estimated to be at least one log higher when expressed as substitution/site/day. The precise localisation of the detected nucleotide point mutations (substitution, deletion and insertion) were reported as well as the quantitative increase or decrease of the sequences harbouring them along ten cell culture passages. The non-silent amino acid mutations were also depicted in 3D models for four out of the five studied regions. These results have important implications for different norovirus research fields, especially in terms of diagnosis, classification methodology and genetic evolution. [less ▲]

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See detailEvaluation of process-driven spray retention model on ear-ly growth stage barley
Massinon, Mathieu ULg; Ouled Taleb Salah, Sofiene ULg; De Cock, Nicolas ULg et al

Conference (2014, July)

The efficiency of spray application of foliar plant protection products with hydraulic nozzles on vertically oriented and hydrophobic plants at early growth stages can be very low. The spray retention by ... [more ▼]

The efficiency of spray application of foliar plant protection products with hydraulic nozzles on vertically oriented and hydrophobic plants at early growth stages can be very low. The spray retention by crop leaves is affected by application parameters resulting from nozzle kind, size and operating pressure as well as spray mixture physicochemical properties. When optimizing the spray application, such targets are often used to perform retention trials for comparative purpose, i.e. indoor grown monocotyledonous at two leaves stage. A typical arrangement consists in spraying few plants sufficiently spaced underneath the nozzle to avoid interference due to secondary droplets from impacts on other plants. However, retention trials turn out to ineffective for significantly discriminating between application methods and mixtures due to the high variability between trials resulting from the different droplets retained by each plant. An alternative to retention trials is to tackle spray retention with a physical approach at the droplet scale. Such tests are often performed using high speed imaging with high magnification optics to characterize droplet impacts; adhesion, rebound or shatter on small excised leaf areas and neglect, however, the overall plant architecture. The aim of this paper is to evaluate a droplet interception model connecting actual spray retention with process-driven retention models. In this study, barley plants (BBCH11) were sprayed with 2 formulations using the same nozzle. The actual spray retention was assessed by dosing a fluorescent tracer added to the sprayed mixture. The plants were placed linearly below the center of a single moving nozzle during sprayings. Each plant was reconstructed in 3D afterwards using a structured light 3D scanner and used as input for the model. A virtual nozzle was built on the base of droplet size distributions measured with high speed shadow imaging by performing an adjustment of the distribution by the method of moments. A ran-dom droplet distribution was allocated for each spraying of a barley plant. Droplet velocities were given to droplets on the basis of the droplet velocity – diameter correlation by resolving the droplet transport equations for different droplet sizes. Initial droplet positions were ran-domly given. The interception model is based on a mathematical formalism for the intercep-tion between triangles of the 3D plant and droplet directions. If the droplet impacts a leaf, the amount actually retained by the leaf was computed on the basis of the droplet impact energy and impact behavior from experiments with high speed shadow imaging. In conclusion, the interception model allowed determining the spray retention by plants and discriminating ap-plication parameters by explaining the variability resulting from various droplet size distribu-tions intercepted by single plant. [less ▲]

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See detailEnhancement of ray tracing method for radiative heat transfer with new isocell quasi-monte carlo technique and application to EUI space instrument
Jacques, Lionel ULg; Masset, Luc ULg; Kerschen, Gaëtan ULg

in Proceedings of the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, HEFAT2014 (2014, July)

Monte Carlo ray tracing method for thermal analysis. The rationale for this research is the speed-up of radiative heat transfer computation with the Finite Element Method, widely used in mechanical ... [more ▼]

Monte Carlo ray tracing method for thermal analysis. The rationale for this research is the speed-up of radiative heat transfer computation with the Finite Element Method, widely used in mechanical engineering especially for space structure design but not yet often for thermal analysis of these structures. Based on Nusselt’s analogy, the ray direction sampling is done by sampling the unit disc to derive the ray directions. Stratified sampling is applied to the unit disc that is divided into cells or strata into which random points are generated. The isocell method relies on cells that have the particularity of presenting almost the same area and shape. This enhances the uniformity of the generated quasi-random sequence of ray directions and leads to faster convergence. The isocell method is associated with different surface sampling to derive REFs. The method is benchmarked against ESARAD, the standard ray tracing engine of the thermal analysis software used in the European aerospace industry. Various geometries are used. In particular, one entrance baffle of the Extreme Ultraviolet Imager (EUI) instrument developed at the Centre Spatial de Liège in Belgium is presented. The EUI instrument of the Solar Orbiter European Space Agency mission and will be launched in a 0.28 perihelion orbit around the Sun in 2018. [less ▲]

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See detailInventory-routing problem with pickups and deliveries of RTI in closed-loop supply chain
Limbourg, Sabine ULg

Scientific conference (2014, July)

Reducing environmental impact, related regulations and potential for operational benefits are the main reasons why companies share their Returnable Transport Items (RTIs) among different partners of a ... [more ▼]

Reducing environmental impact, related regulations and potential for operational benefits are the main reasons why companies share their Returnable Transport Items (RTIs) among different partners of a closed-loop supply chain. This research deals with an inventory-routing problem with pickups and deliveries of RTIs. A mixed-integer linear program is developed and tested on small instances. To handle realistic large size problems, a clustering algorithm is coupled with a simulation model. This hybrid heuristic allows assessing the benefits of information and RTIs sharing among partners. [less ▲]

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