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See detailExcitation dependence of photoluminescence transitions
Spindler, Conrad UL

Poster (2016)

Detailed reference viewed: 54 (6 UL)
Peer Reviewed
See detailComplex problem solving and intelligence. A meta-analysis
Stadler, Matthias; Becker, N.; Gödker, M. et al

Poster (2016)

Detailed reference viewed: 123 (1 UL)
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See detailDiscrete mechanical models and upscaling techniques for discrete materials
Beex, Lars UL; Bordas, Stéphane UL

Poster (2016)

Numerous natural and man-made materials are essentially discrete structures at the mesoscale or microscale (see Fig. 1). Discrete mechanical models can be formulated to capture typical mechanical ... [more ▼]

Numerous natural and man-made materials are essentially discrete structures at the mesoscale or microscale (see Fig. 1). Discrete mechanical models can be formulated to capture typical mechanical phenomena arising from this discreteness. Failure in these materials, which often starts with the fracture of an individual bond, can be predicted based on the small-scale mechanics with these models. For failure, but also for non-local mechanics, no phenomenological descriptions are required in these models. This makes them more predictive than constitutive material models for this type of materials. [less ▲]

Detailed reference viewed: 113 (5 UL)
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See detailSome Properties of Homogenous Trellis-Constrained Codes
Franck, Christian UL; Sorger, Ulrich UL

Poster (2016)

We consider Homogenous Trellis-Constrained Codes (HTCC), a generalization of Turbo-codes where all bits are constrained. No efficient decoding algorithm is known for these codes, so our results are ... [more ▼]

We consider Homogenous Trellis-Constrained Codes (HTCC), a generalization of Turbo-codes where all bits are constrained. No efficient decoding algorithm is known for these codes, so our results are primarily of theoretical interest. We propose a technique to derive an upper bound for the maximum-likelihood (ML) decoding of BSC errors. Our tech- nique is based on the weight distributions of the constituent codes and it can also be used when a specific number of errors e is known. We observe that with an ML-decoder some HTCC codes exhibit an error correcting performance close to that of random codes. For those codes we also observe a significant performance gap between ML-decoding and practical decoding based on belief-propagation. [less ▲]

Detailed reference viewed: 140 (7 UL)
Peer Reviewed
See detailVorurteile von Grundschüler/innen gegenüber fiktiven Kindern unterschiedlicher Herkunft.
Paßreiter, L; Schäfer, A.; Baudson, Tanja Gabriele UL

Poster (2016)

Detailed reference viewed: 37 (0 UL)
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See detailEvaluation of a CFD-Simulation approach for modelling CO2 evaporation in microchannels in Ansys Fluent using a mixture-model
Dvorak, Tom; Mazitzis, Nikolaos; Cousin, René et al

Poster (2016)

Microchannels shall be used for evaporation of CO2 in a heat-pump cycle of a hybrid PV-module with direct heat recovery (PVT-direct). In order to predict the required tube length and the expected pressure ... [more ▼]

Microchannels shall be used for evaporation of CO2 in a heat-pump cycle of a hybrid PV-module with direct heat recovery (PVT-direct). In order to predict the required tube length and the expected pressure losses of the microchannel evaporator, a CFD simulation model was implemented and evaluated. The simulation shall finally help finding the adequate size of the evaporator and optimize its geometry. For the simulation the software “Fluent” was chosen using the two phase mixture-model including the Lee-model for evaporation. As the tubes in the microchannel system represent an axis-symmetric setup, a 2D-geometry is sufficiently suitable for the model and its mesh. After an initial testing of the mixture model, it could be seen that the conservation of mass and energy were not correctly calculated with the advised standard set of parameters, neither the phase change mechanism with its characteristic latent heat. In order to get reasonable results with the mixture model, the input parameters of the evaporation rate and the bubble diameter were systematically varied and validated by manual calculation based on experimental data published in the standard literature. To further improve the numerical quality and stability of the simulation, solver parameters were changed. The adjustment of discretization schemes and the under-relaxation factors were most successful. The effect of different boundary conditions for solar radiation and convective heat on the relevant evaporator surface was also investigated. The test simulations showed that the mixture model is appropriate for a low vapor volume fraction but maybe reaches its limits at higher vapor volume fractions as the flow regime changes. It needs more investigation to prove if drop-evaporation will be sufficiently represented by the chosen model. Consequently, the modelling approach must be optimized and validated for the relevant volume vapor fraction of up to 95 Vol %. This will be the task for the future. And also completely different model approaches have to be considered. [less ▲]

Detailed reference viewed: 227 (0 UL)
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See detailAssessment of BLT Tide Gauge Benchmark Monitoring (TIGA) repro2 Solutions
Hunegnaw, Addisu UL; Teferle, Felix Norman UL

Poster (2015, December 17)

In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning ... [more ▼]

In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning System (GPS) observations from 1994 to 2013. This re-processed dataset will provide high quality estimates of land motions, enabling regional and global high-precision geophysical/geodetic studies. Several of the individual TIGA Analysis Centres (TACs) have completed processing the full history of GPS observations recorded by the IGS global network, as well as, many other GPS stations at or close to tide gauges, which are available from the TIGA data centre at the University of La Rochelle (www.sonel.org). Following the recent improvements in processing models and strategies, this is the first complete reprocessing attempt by the BLT TIGA Analysis centre to provide homogeneous position time series. We report the quality of the multi-year daily solutions from the consortium of the British Isles continuous GNSS Facility (BIGF) and the University of Luxembourg TIGA Analysis Centres (BLT) based on the Bernese GNSS Software Version 5.2 using a double difference (DD) network processing strategy. [less ▲]

Detailed reference viewed: 86 (9 UL)
Peer Reviewed
See detailMetacognitive approach of decision processes implied in time perception
Lamotte, Mathilde UL; Droit-Volet, Sylvie; Izaute, Marie

Poster (2015, November)

Detailed reference viewed: 43 (0 UL)
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See detailSignal Obstructions at GNSS Stations: Benefits From Multi-GNSS Observations
Abraha, Kibrom Ebuy UL; Teferle, Felix Norman UL; Hunegnaw, Addisu UL et al

Poster (2015, October 27)

The current accuracy of IGS products, few centimeter level, requires amongst other things that the location for GNSS antennas are nearly optimal for GNSS observations. This includes a low multipath ... [more ▼]

The current accuracy of IGS products, few centimeter level, requires amongst other things that the location for GNSS antennas are nearly optimal for GNSS observations. This includes a low multipath environment and little to no signal obstructions. However, this is not guaranteed for every station especially in urban areas and mountainous regions. As some applications such as GNSS for sea level studies or to monitor landslides require GNSS antennas to be installed at a specific site, it is clear that the environment might not be favourable for GNSS observations. In this study, we investigate the effect of signal obstructions on station positions, specifically the height component, based on simulated obstruction scenarios using a modified Bernese GNSS Software version 5.2 (BSW52). The behaviours of different obstruction scenarios and the impact of multi-GNSS (GPS+GLONASS for now) observations for both clear and obstructed stations are discussed. [less ▲]

Detailed reference viewed: 163 (19 UL)
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See detailPraxis- a Kontaktdag
Böwen, Petra UL; Dujardin, Céline UL; Romberg, Kathrin UL

Poster (2015, October 22)

Wir bieten Studierenden und Arbeitgebern die Möglichkeit, persönlichen Kontakt herzustellen und/oder zu pflegen. Auch Studieninteressierte und die interessierte Öffentlichkeit können „Wissenschaft und ... [more ▼]

Wir bieten Studierenden und Arbeitgebern die Möglichkeit, persönlichen Kontakt herzustellen und/oder zu pflegen. Auch Studieninteressierte und die interessierte Öffentlichkeit können „Wissenschaft und Praxis“ hautnah erleben. Im Mittelpunkt steht der persönliche Kontakt. Sie als Praxiseinrichtungen bekommen die Möglichkeit, sich und Ihre Arbeit zu präsentieren. Sie können Kontakte mit potentiellen Praktikanten, Honorarkräften und evtl. zukünftigen Berufseinsteigern herstellen und auch ehrenamtliche Mitarbeiter gewinnen. Sie als Studierende können Kontakte knüpfen für ein konkretes Praktikum, zum Kennenlernen eines bestimmten Praxisfeldes oder zur Kontaktaufnahme mit einem potentiellen Arbeitgeber. [less ▲]

Detailed reference viewed: 91 (7 UL)
Peer Reviewed
See detailMath anxiety is predicted by the strength of number-space associations, over and beyond arithmetic ability and WM
Georges, Carrie UL; Hoffmann, Danielle UL; Schiltz, Christine UL

Poster (2015, October)

Math skills are undeniably important in everyday life. Math anxiety can, however, threaten their optimal development. Given that a fifth of the population experiences high math anxiety, it is important to ... [more ▼]

Math skills are undeniably important in everyday life. Math anxiety can, however, threaten their optimal development. Given that a fifth of the population experiences high math anxiety, it is important to identify its origins in order to improve mathematical learning. Research on math anxiety typically focusses on the effects of math ability, WM, and spatial performance. Recent evidence, however, suggests that it also depends on basic numerical processes, with high math anxious individuals featuring less precise numerical representations, as indexed by stronger distance effects. Another marker for the nature of numerical representations is the SNARC effect, alluding to their spatial organization. Although number-space associations depend on WM, spatial performance and arithmetic ability - all related to math anxiety - their relationship with the latter has never been tested. We thus determined whether math anxiety is related to the strength of number-space associations. All participants (n=60, 28 female) completed the r-MARS, the parity judgment, an arithmetic, and visuospatial WM task. We replicated previous findings on the negative relationships between math anxiety and arithmetic ability (r=-0.3, p=0.02), and WM (r=-0.29, p=0.03). But most importantly, we found a significant negative correlation between the SNARC effect and math anxiety (slope=-11.42, r=-0.43, p<0.001), with high math anxious individuals featuring greater interference of the irrelevant magnitude-associated spatial code. Interestingly, number-space associations were the only significant predictor of math anxiety in a multiple regression analysis. Our findings thus provide further evidence for the association between numerical representations and math anxiety, over and beyond arithmetic ability and WM. [less ▲]

Detailed reference viewed: 100 (10 UL)
See detailQuantum moment maps and retracts for symmetric bounded domains
Korvers, Stéphane UL

Poster (2015, October)

Detailed reference viewed: 35 (1 UL)
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See detailHow does Language influence Number transcoding?
Poncin, Alexandre UL; Van Rinsveld, Amandine; Schiltz, Christine UL

Poster (2015, September 29)

The German number word system inverts units and tens compared to the Arabic notation. This is not the case in French, which is more transparent with respect to the Arabic number code. The linguistic ... [more ▼]

The German number word system inverts units and tens compared to the Arabic notation. This is not the case in French, which is more transparent with respect to the Arabic number code. The linguistic structure of number words can facilitate or impede numerical development and performances in number transcoding tasks. We used an original transcoding paradigm with 4th grade French-speaking children, 4th grade German-speaking children, as well as French-speaking and German-speaking young adults who listened to two-digit numbers and had to identify the heard number among four visually presented Arabic numbers. The novelty of our paradigm consisted in manipulating the order of appearance of the units and tens of the Arabic numbers, leading to three conditions: units-first, tens-first and simultaneous appearance. Results revealed that German-speaking children were globally slower than their French-speaking peers. In contrast, language did not affect overall transcoding speed in young adults. Moreover children from both language groups were faster in transcoding when the order of digit appearance was congruent with the number word system (i.e. units-first in German and tens-first in French) compared to the incongruent and the simultaneous presentation order. This pattern indicates that children tended to process number sequentially during the transcoding task. This pattern differed from the behavior observed in adult, since both German- and French-speaking adults solved the transcoding task faster when tens were presented before units (i.e. tens-first) than the reverse. [less ▲]

Detailed reference viewed: 73 (6 UL)
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See detailIdentification with Europe – a matter of exposure?
Murdock, Elke UL; Ferring, Dieter UL

Poster (2015, September 11)

Research on European identity has consistently found low identification with the supra-national category European for participants with low experience levels of Europe. In some instances, higher ... [more ▼]

Research on European identity has consistently found low identification with the supra-national category European for participants with low experience levels of Europe. In some instances, higher experience levels of Europe, for example through language competence, exchange programs or work experience have also produced higher levels of identification with Europe. However, overall identification levels with Europe rest still low. To assess the impact of exposure to Europe on identification with Europe, two empirical studies were carried out among adolescents who are growing up with high experience levels of Europe. Participants are students at the European School of Luxembourg, which is divided into language sections representing the member states of the European Union. The students learn a second language from Primary school onwards and more languages are added later on. They attend weekly “European hour” classes and many parents work for one of the European institutions located in Luxembourg. Luxembourg itself is a trilingual country, sharing borders with three countries and a foreign population of 44%. In the first study, 106 students, average age M = 13.64, SD = 1.72 participated and the salience of the supra-national category European was assessed in the spontaneous self-concept using a modified version of the Twenty Statement Test. None of the European school students mentioned “European” in their spontaneous self-concept. In the second study (N = 204, average age M =15.16, SD = 0.84) students were asked to self-categorize in terms of nationality. Bicultural self-definitions were common, but only one student described herself as “European”. These findings amongst the high exposure group to Europe are discussed against a background of identity theories including theories on national identity and wider collective identities. I will argue that European identity is likely to remain elusive and alternative research approaches are suggested within a globalizing world. [less ▲]

Detailed reference viewed: 47 (6 UL)
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See detailZur Relevanz psychosozialer Arbeitsbedingungen und mentaler Arbeitsanforderungen für das Erleben von Stress und Burnout.
Sischka, Philipp UL; Steffgen, Georges UL

Poster (2015, September 07)

Das Job Demands-Resources-Modell(JD-R-Modell, z.B.Bakker & Demerouti, 2007; Schaufeli, Bakker, vanRhenen, 2009) weist auf die Bedeutung von psycho-sozialen Arbeitsbedingungen für das Erleben von Stress ... [more ▼]

Das Job Demands-Resources-Modell(JD-R-Modell, z.B.Bakker & Demerouti, 2007; Schaufeli, Bakker, vanRhenen, 2009) weist auf die Bedeutung von psycho-sozialen Arbeitsbedingungen für das Erleben von Stress und Burnout hin. Während unterschiedliche ‚JobDemands‘ (Berufsbelastungen, z.B. emotionale, kognitive, physische) einen negativen Einfluss auf die Gesundheit ausüben können, können sich ‚JobResources‘ positiv auf die Gesundheit auswirken. Diese Ressourcen können unterschiedliche Formen annehmen, z.B. soziale Unterstützung durch Kollegen oder eine hohe Autonomie bei der Arbeit. In dieser Studie wurde geprüft, ob wahrgenommener Respekt, Kooperation mit Arbeitskollegen sowie Autonomie bei der Ausführung der Arbeit als Job Ressourcen einen Einfluss auf das Erleben von Stress und Burnout haben. [less ▲]

Detailed reference viewed: 286 (22 UL)
See detailGroundwater Storage in a Karst Vadose Zone Evidenced Using Gravimetric and Surface-to-borehole ERT Monitoring Systems
Watlet, A.; Kaufmann, O.; Francis, Olivier UL et al

Poster (2015, September 06)

Detailed reference viewed: 159 (11 UL)
See detailProblematizing science as a primary school discipline: Learning from contingencies and diversities
Schreiber, Catherina UL; Siry, Christina UL; Reuter, Robert UL et al

Poster (2015, September 03)

This paper puts the idea of a contingent nature of science at its fore, asking what we as researchers can learn from seemingly irreconcilable differences in our approaches and interpretations to past ... [more ▼]

This paper puts the idea of a contingent nature of science at its fore, asking what we as researchers can learn from seemingly irreconcilable differences in our approaches and interpretations to past, present and future developments in science education. To do so, we aim to explore the potentials of multi-perspectivity in an academic self-experiment. The idea is to problematize science as a school discipline from different theoretical, disciplinary and methodological standpoints. By taking one concrete example of a Luxembourgian primary school curriculum document, four researchers will independently apply their individual lenses on science as a school discipline. Concretely, the coverage of the hedgehog as a “characteristic animal” in our primary school curriculum will be commented on in historical, sociocultural and pedagogical perspectives. This concrete curricular example is seemingly defined and non disputable as a content theme in primary school science education in Luxembourg, and is also to be found in international curriculum policy documents. Yet a seemingly proven fact can be interpreted in multiple ways, not only to bridge controversies, as it is done so often, but as exploring the differences in a self-reflective manner. Through such multiple interpretations, we are specifically looking for inconsistencies between the four different narratives, instead of focusing on consensual conclusions or firm and consistent patterns. Instead we will follow a multi-layered approach to research in order to undertake a métissage approach to analyzing a component of the science pedagogical practice, allowing the different understandings on the Luxembourgian science curriculum to remain and complement each other in a complex manner. [less ▲]

Detailed reference viewed: 205 (41 UL)
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See detailRelationship between cardiovascular reactivity and the perception of the thermal grill illusion of pain
Scheuren, Raymonde UL; Duschek, Stefan; Schulz, André UL et al

Poster (2015, September 03)

Alterations in blood pressure (BP) and concomitant changes in baroreceptor activation contribute to the modulation of pain sensitivity to warrant homeostatic regulation processes [1][2]. Numerous pain ... [more ▼]

Alterations in blood pressure (BP) and concomitant changes in baroreceptor activation contribute to the modulation of pain sensitivity to warrant homeostatic regulation processes [1][2]. Numerous pain studies have described an inverse relationship between BP and nociceptive sensitivity [3][4][5]. It is not known whether a similar relationship plays a role in the framework of the induction of pain in the absence of noxious stimulation. The thermal grill (TG) paradigm is commonly used to trigger this type of paradoxical pain also termed thermal grill illusion of pain (TGI). The goal of the present study was to explore the relationship between cardiovascular activity/reactivity and paradoxical pain sensitivity to get additional insight in the variability of responsiveness (responders and non-responders) to TG stimulation described in the literature [6][7]. We hypothesized that higher BP would be associated with stronger pain inhibitory effects in participants not perceiving the thermal grill illusion of pain (TGI). We moreover expected that the perception of paradoxical pain in the responder group would be paired with lower BP. We tested this hypothesis by comparing both groups with respect to their spontaneous cardiovascular activity (recorded in resting conditions) and their cardiovascular responses to TG stimulation. [less ▲]

Detailed reference viewed: 108 (4 UL)
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See detailCognitive Processing of Interoceptive Information and Negative Health Outcomes
Sütterlin, Stefan; Scheuren, Raymonde UL; Mueller, Sven et al

Poster (2015, September 02)

Detailed reference viewed: 42 (3 UL)
Peer Reviewed
See detailMagnetic SANS correlation functions of bulk magnetic materials
Mettus, Denis UL; Michels, Andreas UL

Poster (2015, September 02)

We present model calculations, based on the continuum theory of micromagnetics, for the correlation function of the spin-misalignment SANS cross section of bulk ferromagnets (e.g. elemental ... [more ▼]

We present model calculations, based on the continuum theory of micromagnetics, for the correlation function of the spin-misalignment SANS cross section of bulk ferromagnets (e.g. elemental polycrystalline ferromagnets, soft and hard magnetic nanocomposites, nanoporous ferromagnets, or magnetic steels). For such materials, the spin disorder which is related to spatial variations in the saturation magnetization and magnetic anisotropy field results in strong spin-misalignment scattering dΣM/dΩ along the forward direction [1]. When the applied magnetic field is perpendicular to the incoming neutron beam, the characteristics of dΣM/dΩ (e.g. the angular anisotropy on a two-dimensional detector or the asymptotic power-law exponent) are determined by the ratio of magnetic anisotropy-field strength Hp to the jump ΔM in the saturation magnetization at internal interfaces. Here, we analyze the corresponding one and two-dimensional real-space correlations as a function of applied magnetic field, ratio Hp/ΔM, single-particle form factor, and particle volume fraction. Finally, we compare the theoretical results for the correlation function to experimental data on a Nd-Fe-B-based nanocomposite. [less ▲]

Detailed reference viewed: 62 (2 UL)
Peer Reviewed
See detailTop-down control over pain in fibromyalgia patients: An experimental study.
Van Ryckeghem, Dimitri; Rost, Silke UL; Van Damme, Stefaan et al

Poster (2015, September)

Detailed reference viewed: 57 (1 UL)
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See detailParafermion bound states and the fractional Josephson effect in Rashba spin-orbit coupled nanowires
Pedder, Christopher UL; Meng, Tobias; Tiwari, Rakesh et al

Poster (2015, September)

Detailed reference viewed: 56 (0 UL)
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See detailActivity tracking and indoor positioning with a wearable magnet
Popleteev, Andrei UL

Poster (2015, September)

This paper presents an unconventional application of digital compass sensors for localization and activity monitoring in ambient assisted living scenarios. Benefits and limitations of the proposed ... [more ▼]

This paper presents an unconventional application of digital compass sensors for localization and activity monitoring in ambient assisted living scenarios. Benefits and limitations of the proposed approach are reviewed and compared to these of traditional tracking methods, such as wearable devices, surveillance cameras and device-free localization. [less ▲]

Detailed reference viewed: 154 (13 UL)
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See detailThe link between number-space associations and visuospatial abilities depends on visualization profile
Georges, Carrie UL; Hoffmann, Danielle UL; Schiltz, Christine UL

Poster (2015, September)

Background: Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster RTs to small/large digits with the left/right hand ... [more ▼]

Background: Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster RTs to small/large digits with the left/right hand respectively. However, the cognitive origin of the effect remains elusive. Previous studies suggested that it might depend on visuospatial processes, since individuals with better performances in 2D (but not 3D) mental rotation tasks displayed weaker number-space associations (Viarouge et al., 2014). Aims: Given the high inter-individual variability of number-space associations, we determined whether the SNARC effect always relies on visuospatial processes or whether its cognitive origin varies with visualization preferences. Method: We distinguished between object-visualizers (n=42, 23 female, age=22.93) and spatial-visualizers (n=42, 15 female, age=23.9) using the Object-Spatial Imagery Questionnaire (Blajenkova et al., 2006). All participants performed the parity judgment task, a 2D visuospatial test and a 3D mental rotation task. Results: In object-visualizers, weaker SNARC slopes were associated with better performances in the 2D (r=0.46, p=0.004), but not 3D (r=-0.04, p=0.79) task, thereby replicating previous observations. Conversely, in spatial-visualizers, the performances in both visuospatial tasks were unrelated to the SNARC effect (2D: r=0.02, p=0.89; 3D: r=0.2, p=0.22). Conclusions: These findings suggest that in object-visualizers, number-space associations and 2D performances underlie common visuospatial processes. Conversely, in spatial-visualizers, number-space associations seem to result from cognitive mechanisms other than those recruited during the aforementioned visuospatial tasks (e.g., verbal-spatial coding mechanisms). All in all, we were able to further unravel the mechanisms underlying number-space associations and could highlight visualization preferences as an additional explanation for the great inter-individual variability of the SNARC effect. [less ▲]

Detailed reference viewed: 74 (9 UL)
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See detailDoes body motion influence arithmetic problem solving
Sosson, Charlotte UL; Guillaume, Mathieu UL; Schuller, Anne-Marie UL et al

Poster (2015, September)

Recent evidence indicates that body movements can influence number processing (Hartmann, et al., 2012) and arithmetic problem solving (Lugli, et al., 2013). Thus it was for instance observed that moving ... [more ▼]

Recent evidence indicates that body movements can influence number processing (Hartmann, et al., 2012) and arithmetic problem solving (Lugli, et al., 2013). Thus it was for instance observed that moving the arm rightward and upward led to better performance during additions and leftward and downward during subtractions (Wiemers, et al., 2014). These results could be explained by the fact that left/right body motion can be (in)compatible with the attentional motion towards the left/right on the mental number line known to underlie subtractions/additions (i.e. operational momentum effect) (McCrink, et al., 2007; Lindemann, et al., 2011). The compatible situations (i.e. leftwards motion - subtraction and rightwards motion - addition) thus are expected to facilitate arithmetic performance compared to incompatible ones. The present study was designed to test this hypothesis during arithmetic problem solving using: (1) physical passive rotary whole-body motion and (2) virtual environment mimicking a similar passive body motion. Findings of the present study confirm the classical effects known to play a role in arithmetic problem solving. They also revealed that passive rotary whole-body motion - implemented physically or by virtual reality - had no particular effect on the solving of calculations. This is in contrast with previous studies that showed an influence of active head/arm or passive translational movements on numerical task performance. [less ▲]

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See detailElectronic and Vibrational proprieties of graphene on Ir(111) and SiC(100)
Pereira Coutada Miranda, Henrique UL; Molina-Sanchez, Alejandro UL; Wirtz, Ludger UL

Poster (2015, September)

In the last years, graphene has become one of the most studied materials due to its peculiar electronic, optical, thermal, and mechanical properties. It is thus of major importance, for practical ... [more ▼]

In the last years, graphene has become one of the most studied materials due to its peculiar electronic, optical, thermal, and mechanical properties. It is thus of major importance, for practical applications, to study how the electronic and vibrational proprieties of graphene change when deposited on a substrate. The non-commensurability of the unit cell of graphene with the substrate leads to the formation of Moiré patterns with accordingly large supercell sizes. Ab-initio calculations using standard plane-wave based codes on these large systems are of high computational cost even for the ground-state calculations. We show the effect that such Moiré patterns have on the band structure by projecting the resulting electronic structure and phonon dispersion onto the unit cell of free-standing graphene with an unfolding scheme. We compare our results with HREELS measurements of the phonon dispersion of graphene on Ir(111). The accurate knowledge of the interaction graphene-substrate will provide important information for future applications of graphene on electronic devices. Work performed in collaboration with the experimental groups of J. Kroeger (TU Ilmenau, Germany) and T. Seyller (TU Chemnitz, Germany). [less ▲]

Detailed reference viewed: 197 (3 UL)
Peer Reviewed
See detailMagnetic small-angle neutron scattering: beyond the particle-matrix concept
Michels, Andreas UL

Poster (2015, September)

Detailed reference viewed: 48 (2 UL)
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See detailA global description of the fine Simpson moduli space of 1-dimensional sheaves supported on plane quartics
Iena, Oleksandr UL

Poster (2015, September)

We give a global description of the fine Simpson moduli spaces of 1-dimensional sheaves supported on plane quartics.

Detailed reference viewed: 45 (10 UL)
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See detailFracture in augmented reality
Bilger, Alexandre UL; Cotin, Stephane; Dequidt, Jeremie et al

Poster (2015, August)

Detailed reference viewed: 113 (1 UL)
See detailRaman spectroscopy as probe of nanometre-scale strain variations in graphene
Neumann, Christoph; Reichardt, Sven UL; Venezuela, Pedro et al

Poster (2015, July 14)

Detailed reference viewed: 99 (1 UL)
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See detailDevelopment and validation of a test intrument to assess basic motor qualifications in primary school
Scheuer, Claude; Bund, Andreas UL; Herrmann, Christian

Poster (2015, July)

Detailed reference viewed: 52 (3 UL)
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See detailFEniCS in Linux Containers
Hale, Jack UL; Li, Lizao; Wells, Garth N.

Poster (2015, June 29)

We present a collection of Docker images for running FEniCS in Linux containers. With one command, a user can launch a lightweight container that provides a consistent environment for using or developing ... [more ▼]

We present a collection of Docker images for running FEniCS in Linux containers. With one command, a user can launch a lightweight container that provides a consistent environment for using or developing FEniCS. Once the initial image has been fetched, 'FEniCS terminals' can be launched near-instantly. We show through a range of tests that performance within a container is to equal to that on the host system. Moreover, MPI programs can be run from inside the container, and host CPU vectorisation features can be exploited. In practice, container versions of FEniCS will be faster than user installations as the container images can be carefully tuned for performance. Live demonstrations of user and developer container use will be presented. The containers are built and hosted on Docker Hub [less ▲]

Detailed reference viewed: 154 (18 UL)
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See detailImpact of Limited Multi-GNSS Visibility on Vertical Land Movement Estimates
Abraha, Kibrom Ebuy UL; Teferle, Felix Norman UL; Hunegnaw, Addisu UL et al

Poster (2015, June 27)

The number of GNSS satellites and their geometry directly affect the quality of positioning and derived satellite products. Accordingly, the International GNSS Service (IGS) recommends GNSS antennas to be ... [more ▼]

The number of GNSS satellites and their geometry directly affect the quality of positioning and derived satellite products. Accordingly, the International GNSS Service (IGS) recommends GNSS antennas to be installed away from natural and man-made surfaces and structures, which may affect the incoming signals through severe multipath or obstructions. Following these recommendations, continuous GNSS (cGNSS) stations are generally located in low multipath environments with minimal signal obstructions. However, some applications require GNSS antennas to be installed at specific locations in order to measure local processes. Hence, in support of sea level studies, cGNSS stations must be installed close to or at tide gauges in order to accurately monitor the local vertical land movements experienced by the sea level sensors. However, the environment at the tide gauge might not be optimal for GNSS observations due to the aforementioned station-specific effects, which degrade the quality of coordinate solutions.This first study investigates the impact of severe signal obstructions on long-term monitoring results by use of simulated and real observations for selected cGNSS stations, and evaluates if the use of multi-GNSS (GPS+GLONASS) constellations will benefit derived results. To investigate these effects, we implemented azimuth and elevation dependent masking in the Bernese GNSS Software version 5.2. We present our preliminary results on the impact of different obstruction scenarios and combined GPS and GLONASS solutions on coordinate and vertical land movement estimates. [less ▲]

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See detailCalibration of the Tide Gauge at King Edward Point, South Georgia Island, South Atlantic Ocean
Teferle, Felix Norman UL; Hunegnaw, Addisu UL; Woodworth, P. L. et al

Poster (2015, June 27)

In 2008 a new pressure tide gauge with Global Sea Level Observing System Number 187 was installed at King Edward Point (KEP), South Georgia Island, South Atlantic Ocean. This installation was carried out ... [more ▼]

In 2008 a new pressure tide gauge with Global Sea Level Observing System Number 187 was installed at King Edward Point (KEP), South Georgia Island, South Atlantic Ocean. This installation was carried out as part of the Antarctic Circumpolar Current Levels by Altimetry and Island Measurements (ACCLAIM) programme. In 2013 the KEP Geodetic Observatory was established in support of various scientific applications including the monitoring of vertical land movements at KEP. Currently, the observatory consists of two state-of-the-art Global Navigation Satellite System (GNSS) stations with local benchmark networks. This ties all benchmarks and the tide gauge into the International Terrestrial Reference Frame 2008, and allows the establishment of a local height datum in a global height system through the use of a global gravitational model. In 2014 a tide board was added to the tide gauge, which, together with the GNSS and levelling observations, now enables a calibration of the tide gauge. This will make it possible to include the KEP tide gauge in the Permanent Service for Mean Sea Level (PSMSL) database. In this study, we will present the results from the calibration of the tide gauge using the GNSS observations from the KEP Geodetic Observatory for the period from February 2013 to present, the levelling campaigns in 2013 and 2014, and geoid undulations derived from a seamless combination of the latest Gravity Observation Combination (GOCO) 05S and Earth Gravitational Model (EGM) 2008 models. [less ▲]

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See detailShared alterations in the human brain transcriptome during adult aging and in Parkinson's disease
Glaab, Enrico UL; Schneider, Reinhard UL

Poster (2015, June 15)

Aging-related biomolecular changes in the human brain are thought to be associated with an increased risk for neurodegenerative diseases. In particular, aging and Parkinson’s disease (PD) share various ... [more ▼]

Aging-related biomolecular changes in the human brain are thought to be associated with an increased risk for neurodegenerative diseases. In particular, aging and Parkinson’s disease (PD) share various molecular hallmarks, including a gradual decline in dopamine synthesis and increased levels of deleted mitochondrial DNA. While some specific mechanistic links between brain aging and PD have been proposed and investigated previously, systematic analyses of shared molecular alterations at a genome-scale level are required to obtain a better understanding of the affected cellular processes and their interrelations. We present a joint analysis of high-throughput brain transcriptomics data from PD patients and unaffected individuals from different adult age groups using a statistical meta-analysis and a recently published pathway and network analysis approach. Our analyses provide statistical evidence for specific functional associations between molecular network changes in PD and aging, identify new significant joint pathway deregulations and suggest mechanistic explanations for the observed age-dependence of PD risk. [less ▲]

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See detailA New Datum-Controlled Tide Gauge Record for Sea Level Studies in the South Atlantic Ocean: King Edward Point, South Georgia Island
Teferle, Felix Norman UL; Hunegnaw, Addisu UL; Woodworth, P. L. et al

Poster (2015, June 12)

In 2008 a new pressure tide gauge with Global Sea Level Observing System Number 187 was installed at King Edward Point (KEP), South Georgia Island, South Atlantic Ocean. This installation was carried out ... [more ▼]

In 2008 a new pressure tide gauge with Global Sea Level Observing System Number 187 was installed at King Edward Point (KEP), South Georgia Island, South Atlantic Ocean. This installation was carried out as part of the Antarctic Circumpolar Current Levels by Altimetry and Island Measurements (ACCLAIM) programme. In 2013 the KEP Geodetic Observatory was established in support of various scientific applications including the monitoring of vertical land movements at KEP. Currently, the observatory consists of two state-of-the-art Global Navigation Satellite System (GNSS) stations with local benchmark networks. In 2014 a tide board was added to the tide gauge, which, together with the measurements from the KEP Geodetic Observatory, now enables a calibration of the tide gauge. This will make it possible to include the KEP tide gauge in the Permanent Service for Mean Sea Level (PSMSL) database and make it available for future sea level studies. In this study, we will present the GNSS and levelling observations from the KEP Geodetic Observatory for the period from February 2013 to May 2015 used for the calibration of the tide gauge. While it is still too early to obtain accurate vertical land movement estimates from the GNSS data, the levelling campaigns in 2013 and 2014 indicated 7-9 mm of subsidence near the tide gauge. For the computation of the new height datum, geoid undulations derived from a seamless combination of the latest Gravity Observation Combination (GOCO) and Earth Gravitational Model (EGM) 2008 models were used. The use of this combined gravity model introduced a datum shift of approximately -24 cm compared to the previous datum. [less ▲]

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See detailComment favoriser la collaboration école-famille: la boîte à outils
Kerger, Sylvie UL; Poncelet, Débora UL; Dierendonck, Christophe UL

Poster (2015, June 11)

We presented a tool of concrete actions how to strengthen the relation between school, families and community. These concrete actions were the outcome of an action-research in Luxembourgish fundamental ... [more ▼]

We presented a tool of concrete actions how to strengthen the relation between school, families and community. These concrete actions were the outcome of an action-research in Luxembourgish fundamental schools. This set of actions is not a " ready for use kit " but rather a "guide" in the transposition of experiences of a situation given to an other. [less ▲]

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See detailNon-integral torsion and 1-dimensional singular sheaves in the Simpson moduli space
Leytem, Alain UL

Poster (2015, June 01)

In my thesis I am interested in the Simpson moduli spaces $M_{am+b}$ of semi-stable sheaves on $P_2$ with linear Hilbert polynomial $am+b$ where $a,b\in N$. More precisely I want to know which ones and ... [more ▼]

In my thesis I am interested in the Simpson moduli spaces $M_{am+b}$ of semi-stable sheaves on $P_2$ with linear Hilbert polynomial $am+b$ where $a,b\in N$. More precisely I want to know which ones and “how many” of them are locally free on their support. I also started a study apart to analyze how torsion of a module behaves in the non-integral case. Apparently this has not been done in detail yet. [less ▲]

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See detailFunctional connectivity and structural analyses in the bilingual brain: implications for arithmetic.
Van Rinsveld, Amandine UL; Dricot, Laurence; Guillaume, Mathieu UL et al

Poster (2015, June)

Do bilinguals use the same brain networks than monolinguals when they solve arithmetic problems? We investigated this question by using resting-state functional connectivity and cortical thickness ... [more ▼]

Do bilinguals use the same brain networks than monolinguals when they solve arithmetic problems? We investigated this question by using resting-state functional connectivity and cortical thickness measurements. Recent studies highlighted differences of functional connectivity (e.g. Grady et al., 2015) and of brain structure (e.g. Klein et al., 2014) between bilinguals and monolinguals. However, no study so far has linked these differences to arithmetic problem solving, a cognitive skill that may at least partially rely on language processing. Our study population was composed of carefully selected German-French bilinguals (N = 20) who acquired each language at the same age, leading to high proficiency levels in both languages. These bilinguals all attended university in their second language at the time of the experiment, namely French. Therefore we selected a control group of French-speaking monolinguals (N = 12). Structural and functional images of brain activity were collected using a 3T MRI scanner. Functional scans of resting-state were acquired during a 6-minute session, with eyes closed. A 3D T1-weighted data set encompassing the whole brain was acquired to provide detailed anatomy (1 mm3), which was used both for the co-registration of functional data and for morphometric analyses. Prior to the scanning session, all participants took a behavioral test measuring their arithmetic skill. For the resting-state part of the study, we generated spheres based on ROIs reported in the literature as magnitude manipulation- and language-related areas during arithmetic problem solving (Klein et al. 2013), and addition-related areas reported in a recent meta-analysis (Arsalidou & Tayor, 2011). We used these spheres as seed regions for the analyses. We correlated resting activations between these regions and compared these correlations in bilinguals versus monolinguals. Results showed significantly higher correlations between the three seed regions in monolinguals than in bilinguals (all ts > 2.306; ps < .05), suggesting that regions used to solve arithmetic problems form a different network in bilinguals than in monolinguals. To control for general differences between both populations, we also created two spheres in areas not specifically related to neither arithmetic nor language regions. There were no significant differences between groups in terms of correlations of these regions with resting-state activations. These results suggest that the differences observed in arithmetic problem solving regions could not account for by general differences between groups. In the second part of the study, we aimed at verifying whether the differences in functional connectivity we observed between bilinguals and monolinguals coincide with structural brain differences. We measured and compared cortical thickness in both groups. Then we compared the correlations between cortical thickness and arithmetic skill in both groups (considering differences with corrected p < .001). Cortical thickness of areas commonly associated to language or number processing correlated differently with arithmetic skill as a function of the group: Higher cortical thickness of left pars triangularis, bilateral superior parietal gyri and precuneus positively correlated with arithmetic skill in monolinguals but negatively correlated with arithmetic skill in bilinguals. These results highlight that there are different relations between brain structure and arithmetic skills in bilinguals and monolinguals. In conclusion the current study provides new evidence for differences between bilinguals’ and monolinguals’ brain networks engaged in arithmetic problem solving, even without any arithmetic task during the data acquisition. These findings based on functional connectivity and brain structure analyses also reveal the general involvement of language in arithmetic problem solving in bilingual as well as non-bilingual individuals. [less ▲]

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See detailLearning movement phases during early stages of learning
Ghorbani, Saeed; Bund, Andreas UL

Poster (2015, June)

Detailed reference viewed: 48 (2 UL)
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See detailCoping with Bullying questionnaire: Validation of the German adaptation
Pinto Costa, Andreia UL; Steffgen, Georges UL; Skrzypiec, Grace

Poster (2015, May 21)

Detailed reference viewed: 84 (6 UL)
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See detailControl of Flame Spray Pyrolysis synthesis of Li4Ti5O12: Experimental and Computational study
Tsikourkitoudi, Vasiliki; Gavriliadis, Panagiotis; Bourantas, Georgios UL et al

Poster (2015, May 14)

Lithium titanate (Li4Ti5O12, LTO) is a promising anode material for the next generation of lithium ion batteries. Its physical properties and morphology (which consequently affect its electrochemical ... [more ▼]

Lithium titanate (Li4Ti5O12, LTO) is a promising anode material for the next generation of lithium ion batteries. Its physical properties and morphology (which consequently affect its electrochemical performance) highly depend on its synthesis method. Flame spray pyrolysis (FSP) is an attractive process for the controlled one-step synthesis of functional multicomponent oxides from low cost precursors. The main aim of this study is to control the growth process of LTO by FSP in order to maintain the desired particle properties. LTO nanoparticles of different sizes are synthesized by variation of the FSP processing conditions and characterized accordingly. Numerical simulations based on Population Balance Models are also implemented in order to investigate the evolution of primary and agglomerate particle growth. [less ▲]

Detailed reference viewed: 320 (1 UL)
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See detailInhibitory control influences number-space associations in atypical young adults with ADHD
Georges, Carrie UL; Hoffmann, Danielle UL; Schiltz, Christine UL

Poster (2015, May)

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times (RTs) to small/large digits with the left/right ... [more ▼]

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times (RTs) to small/large digits with the left/right hand respectively. The SNARC effect is, however, characterized by high inter-individual variability, depending amongst others on inhibition capacities. Hoffmann et al. (2014) showed that individuals more sensitive to the interference of irrelevant information in the classical color-word Stroop task displayed stronger number-space associations. This relation was most pronounced in elderly, but did not reach significance in young healthy adults. To determine whether the negligible correlation in the young resulted from their near ceiling performances on the color-word Stroop task, we recruited young adults featuring atypically weak and variable inhibitory control. Our study population consisted of individuals (n=32; 18 females; age=27.28 years) formally diagnosed with attention-deficit/hyperactivity disorder (ADHD; n=4) and/or displaying symptoms consistent with ADHD according to the Adult ADHD Self-Report Scale (ASRS-v1.1; n=29). Within this population, a significant negative correlation (r=-0.45; p=0.009) could be observed between the parity SNARC effect (mean slope=-14.17; p<0.001) and Stroop interference, as indexed by the color-word Stroop ratio score (i.e. the difference in RTs between the color-word interference condition and the color naming condition divided by the RT in the word reading condition; mean ratio=0.82). The relationship remained significant even after controlling for arithmetic performance and general processing speed, as assessed using the arithmetic battery (Rubinsten & Henik, 2005; Shalev et al., 2001; mean accuracy=84.61%) and a speeded matching-to-sample task respectively (mean RT=671.86ms; r=-0.47; p=0.008). Our findings thus reveal that stronger number-space associations are associated with weaker Stroop inhibitory control in young adults with atypical attentional profiles, thereby further confirming the similarities between SNARC effects and Stroop-like interference effects. [less ▲]

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See detailNeural correlates of arithmetic problem solving in bilinguals: an fMRI study.
Van Rinsveld, Amandine UL; Dricot, Laurence; Guillaume, Mathieu UL et al

Poster (2015, May)

Detailed reference viewed: 84 (1 UL)
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See detailA Multi-Year Combination of Tide Gauge Benchmark Monitoring (TIGA) Analysis Center Products
Hunegnaw, Addisu UL; Teferle, Felix Norman UL

Poster (2015, April 12)

In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning ... [more ▼]

In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning System (GPS) observations from 1994 to 2013. This re-processed dataset will provide high quality estimates of land motions, enabling regional and global high-precision geophysical/geodetic studies. Several of the individual TIGA Analysis Centres (TACs) have completed processing the full history of GPS observations recorded by the IGS global network, as well as, many other GPS stations at or close to tide gauges, which are available from the TIGA data centre at the University of La Rochelle (www.sonel.org). Following the recent improvements in processing models and strategies, this is the first complete reprocessing attempt by the TIGA WG to provide homogeneous position time series. We report a first multi-year weekly combined solutions from the TIGA Combination Centre (TCC) at the University of Luxembourg (UL) using two independent combination software packages: CATREF and GLOBK. These combinations allow an evaluation of any effects from the combination software and of the individual TAC parameters and their influences on the combined solution. Some major results of the UL TIGA multi-year combinations in terms of geocentric sea level changes will be presented and discussed. [less ▲]

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See detailHydrokinetic Micro-Power Generation in Small Rivers - a New Approach
Norta, David Peter Benjamin UL; Ramanathan, Sriram; Sachau, Jürgen UL et al

Poster (2015, March 25)

The so called German electrical “Energiewende” is mainly based on the installation of solar photovoltaic and wind energy converters as the main new renewable European generation resources. The third ... [more ▼]

The so called German electrical “Energiewende” is mainly based on the installation of solar photovoltaic and wind energy converters as the main new renewable European generation resources. The third renewable energy resource, the hydropower has been already developed within the last decades and grew not significantly in the last years. Since some years the development of smaller hydrokinetic turbines increased. The smaller size of some hydrokinetic turbines enables new, unused sites to be harnessed in smaller rivers. The paper deals with the key specifications of hydrokinetic turbines and their influence on a villages’ energy supply. It introduces the concept of a turbine with variable immersion depths to exploit also locations with a varying water level. Based on historical hydrological data a propeller and oscillating hydrofoil type of hydrokinetic turbine are compared, it was found that the variable immersion depths increases the energy harvest. Furthermore, it is shown that in a generation portfolio of hydrokinetic and solar power plants an average Luxembourgish household theoretically renewable supplied has to exchange less energy with the power grid, the higher its share of hydrokinetic generation is. [less ▲]

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See detailCalibration of the Tide Gauge at King Edward Point, South Georgia Island
Teferle, Felix Norman UL; Hunegnaw, Addisu UL; Woodworth, P L et al

Poster (2015, March 12)

After initial sea level observations in the 1950s, a new pressure tide gauge (Global Sea Level Observing System 187) was installed at King Edward Point (KEP), South Georgia Island, British Overseas ... [more ▼]

After initial sea level observations in the 1950s, a new pressure tide gauge (Global Sea Level Observing System 187) was installed at King Edward Point (KEP), South Georgia Island, British Overseas Territories in the South Atlantic Ocean, in 2008. This was car-ried out as part of the ACCLAIM (Antarctic Circumpolar Current Levels by Altimetry and Island Measurements) programme. In 2013 the KEP Geodetic Observato-ry was established in support of various geoscience applications including the monitor-ing of vertical land movements at KEP. Currently, the observatory consists of two state-of-the-art GNSS stations with local benchmark networks, allowing the height determina-tions from the GNSS antennas to be transferred to the tide gauge and forming a height reference within the International Terrestrial Reference Frame. Finally in 2014, a tide board was added to the tide gauge, which, together with the GNSS and levelling obser-vations, now allows the calibration of the tide gauge. In this study, we will present the results from the calibration of the tide gauge using the GNSS observations from the KEP Geodetic Observatory for the period from February 2013 to present, the levelling campaigns in 2013 and 2014, and geoid undulations de-rived from a seamless combination of the latest GOCO and EGM2008 gravity models. [less ▲]

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See detailAssessing IT Security Standards Against the Upcoming GDPR for Cloud Systems
Bartolini, Cesare UL; Gheorghe, Gabriela UL; Giurgiu, Andra UL et al

Poster (2015, March 11)

This work in progress aims at identifying a mapping between the current security standards (in particular, but not limited to, ISO 27001-2013) and the upcoming regulations in data protection. The aim is ... [more ▼]

This work in progress aims at identifying a mapping between the current security standards (in particular, but not limited to, ISO 27001-2013) and the upcoming regulations in data protection. The aim is to find an overlap between the requirements for data protection and the existing security standards, to measure the gap that a business has to cross (and consequently an estimate of the expenses that it must sustain) to achieve compliance with the GDPR. [less ▲]

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See detail11,8-100% Rural Renewable Energy and Power Supply and its Influence on the Luxembourgish Power System
Norta, David Peter Benjamin UL; Winkler, Christoph; Sachau, Jürgen UL et al

Poster (2015, March 10)

Introduction; Currently, the majority of countries tries to reduce their dependency on fossil fuels by the introduction of renewable resources in their energy systems. In the following the relatively ... [more ▼]

Introduction; Currently, the majority of countries tries to reduce their dependency on fossil fuels by the introduction of renewable resources in their energy systems. In the following the relatively small Luxembourgish electricity system is analysed (0.55 Mio Inhabitants). Current power-system-models mainly focus on larger systems, due to the unavailability of specific consumption-data. Prices and effects on the Luxembourgish power system of different supply scenarios for rural-private households are analysed. Methodology; A linear optimisation for the minimum-cost of the power-supply of all villages with the following renewable energy resources: wind- (max.100kW), solar-PV- and hydrokinetic-power is made. The electricity-demand scales with the number of inhabitants and agricultural-consumers. The wind-power-potential differs with the location of the village. The solar-radiation is assumed to be the equal over the country, due to the small size of approximately 80 by 50 km. The hydrokinetic turbines complete the supply where a village is located close to a river. Results; The minimum cost of the specific village power-supply is the result of the optimization. The installation- and maintenance-cost of each renewable technology are considered. The whole number of rural Luxembourgish private households is considered and their power contribution to the system is estimated for different renewable energy supply scenarios, namely from 11,8% to 100% renewable-energy-scenarios. For each scenario the power exchanged from the village to the grid is calculated in 15-min-steps for 9-years, the amount differs widely with the amount of applied technologies. Discussion; Due to the high share of imported electricity of about 80% in the recent years, every consideration of national power generation does not harm the supply security. Conclusion; Luxembourg is a good model country to analyse the high share of distributed, renewable generators, due to its structure of rural and civic regions and their effects on a central European region with a high electricity consumption. [less ▲]

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See detailDoes body motion influence arithmetic
Sosson, Charlotte UL; Guillaume, Mathieu UL; Schuller, Anne-Marie UL et al

Poster (2015, March)

« Embodiment theory » proposes that bodily actions impact the quality of mental representations. Two recent studies (Loetscher, et al., 2008; Hartmann, et al., 2011) have shown that leftward movements of ... [more ▼]

« Embodiment theory » proposes that bodily actions impact the quality of mental representations. Two recent studies (Loetscher, et al., 2008; Hartmann, et al., 2011) have shown that leftward movements of the head or the body enhanced small number generation while rightward movements increased the generation of larger numbers. The present study aimed to investigate the influence of passive whole-body movement on arithmetic-problem solving. Our design was elaborated in the context of operational momentum effect (Pinhas, & Fischer, 2008; McCrink, et al., 2007). In the domain of arithmetic this effect refers to the fact that outcomes of additions are systematically estimated to be larger than the outcomes of subtractions and vice versa for subtraction (Knops, et al., 2009; Lindemann, et al., 2011). Interestingly this bias is present for non-carry but not for carry problems. To account for the operational momentum effect it has been proposed that subtractions involve an attentional motion towards the left of the mental number line and additions towards the right inducing the above-mentioned under- and over-estimation. In line with these findings we reasoned that passive body motion might orient attention towards the side of the body movement and consequently enhance the attentional shifts supposed to underlie the operational momentum effects that occur during numerical tasks. In the present paradigm participants were sitting blindfolded on a swivel chair. While they were rotated alternatively 180° towards the left and the right with a pace of 49°/sec., they were asked to orally solve different kinds of calculations presented via headphones. Calculations consisted in additions and subtractions (first operand: from 1 to 98; second operand: from 1 to 13 and results: from 3 to 89) that were composed of carry and non-carry problems and had different levels of difficulty (easy: results from 1 to 9; medium: results from 11 to 19; difficult: from 21 to 89). Contrary to our predictions, results indicate that the direction of passive body motion (i.e. leftwards vs. rightwards) did not influence arithmetic performance. Indeed the ANOVA for repeated measures with the factor Motion (left, right), Problem type (carry, non-carry) and Operation type (addition, subtraction) revealed no main effect of motion (F(1,33)= 0,856, p=0.361). In contrast we observed a main effect of Problem type (F(1,33)=29.065, p<0.001), a main effect of Operation type (F(1,33)= 20,721, p<0.001) and a significant interaction of Problem type x Operation type (F(1,30)=5.605,p=0.024). As would be expected from the results observed with classical stationary experiment settings, participants were more accurate while solving additions than subtractions and made less errors with non-carry problems. Moreover the carry effect was larger for subtractions than additions. Analyses of the reaction times led to the same conclusions. These results indicate that orally solving arithmetic problems is not influenced by the direction (leftwards vs. rightwards) of passive rotary body-motion. This finding contrasts with previous observations that active head movements and/or passive translational movements impacts numerical task performance. Future studies which systematically contrast the effects of the different movement types on numerical tasks should help to clarify this discrepancy. [less ▲]

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See detailInhibitory Control Influences the SNARC Effect in Tasks without Explicit Reference to Numerical Magnitude
Georges, Carrie UL; Hoffmann, Danielle UL; Schiltz, Christine UL

Poster (2015, March)

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times to small/large digits with the left/right hand ... [more ▼]

Evidence for number-space associations comes from the spatial-numerical association of response-codes (SNARC) effect, consisting in faster reaction times to small/large digits with the left/right hand respectively. Although the SNARC effect has now been extensively replicated, it is characterized by high inter-individual variability (Wood et al., 2008). For instance, it has been shown to depend on inhibitory control as indexed by the color Stroop effect in the elderly, with individuals having weaker inhibitory control displaying stronger SNARC effects (Hoffmann et al., 2014). Apart from these well-documented inter-individual differences, number-space associations are also influenced by intra-individual factors. Georges et al. (2014) found that in a population of healthy young university students (n=85, 39 females, mean age=23.44 years), the SNARC effect was qualitatively different within single individuals depending on the number-processing task that they performed. While the strength of the SNARC effects were related in a parity and color judgment task (parity slope=-11.58; color slope=-6.79; r=0.36, p=0.001), as well as in the parity and a magnitude comparison task (magnitude slope=-6.98; r=0.36, p=0.001), no relation could be observed between number-space associations in the color and magnitude tasks (r=0.18, p=0.11). These findings indicate that two distinct factors seem to account for the variance related to number-space associations observed during the three tasks. In the present study, we built on these findings while investigating how inhibitory control influences variance in the SNARC effect observed during different numerical tasks. To this aim, we performed a principle component analysis followed by varimax rotation to combine the color and parity SNARC effects (i.e. number-space associations in tasks without explicit reference to numerical magnitude) and the parity and magnitude SNARC effects (i.e. number-space associations in tasks involving semantic number processing) into single factors (color-parity-SNARC and parity-magnitude-SNARC factors respectively). We then investigated how these two extracted SNARC factors were influenced by inter-individual characteristics such as inhibitory control. Inhibitory control was evaluated in a task that involved responding to the color (green or red) of a centrally presented arrow pointing either in the left or right direction by pressing on the left or right hand-side. To get a single inhibitory control measure for each individual, we calculated inverse efficiency scores on compatible and incompatible trials and computed performance differences between those two conditions. The scores of the extracted parity-color-SNARC factor significantly correlated with the inhibitory control measure (μ=109.98ms, SD=85.82ms; r=-0.26, p=0.02), while no relation was observed between inhibitory control and the parity-magnitude SNARC factor scores (r=-0.1, p=0.42). This suggests that individuals with better inhibitory control (i.e. smaller performance differences between compatible and incompatible trials) displayed weaker SNARC effects only in number-processing tasks that required the suppression of an irrelevant numerical (magnitude) code for successful task completion. Number-space associations are characterized by high inter- and intra-individual variability. We determined how the SNARC effect observed in tasks with and without explicit numerical magnitude processing related to inhibitory control. Individuals with better inhibitory control displayed weaker SNARC effects only in tasks requiring the suppression of an irrelevant numerical magnitude. [less ▲]

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See detailA force-constant model of graphene for conductivity calculations
Pereira Coutada Miranda, Henrique UL; Wirtz, Ludger UL

Poster (2015, January)

Transport in graphene is strongly limited by the electron-phonon interaction. Accurate description of the phonon dispersion relations is essential for the study of this interaction. Using current state-of ... [more ▼]

Transport in graphene is strongly limited by the electron-phonon interaction. Accurate description of the phonon dispersion relations is essential for the study of this interaction. Using current state-of-the-art ab initio density-functional theory plane-wave codes, we are limited to systems with few atoms. For larger systems (e.g., nanotubes, nanoribbons), accurate semi-empircal models are needed. We have developed a force constant model for the phonon dispersion of graphene. Our implementation can include a large number of neighbours, which allows us to simulate accurately long-range interaction effects. As shown in previous publications it is possible to reproduce the phonon dispersion frequencies of graphene with a 4th nearest neighbours force constant model. However, some features can only be captured using long-range interactions (Kohn-anomalies, certain phonon eigenvectors). Using an ab initio phonon dispersion calculated with DFPT as reference, we show the nature of the long-range interactions and explore different ways to include them in our semi-empirical model. We also study the dependence of the force constants on charge and strain. Work in collaboration with Jing Li, Yann-Michel Niquet, Luigi Genovese, and Ivan Duchemin from L_Sim, SP2M, UMR-E CEA/UJF-Grenoble 1, INAC, Grenoble, France and Christophe Delerue from IEMN - Dept. ISEN, UMR CNRS 8520, Lille, France [less ▲]

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See detailAssessment of BLT Tide Gauge Benchmark Monitoring (TIGA) repro2 solutions
Hunegnaw, Addisu UL; Teferle, Felix Norman UL

Poster (2015)

In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning ... [more ▼]

In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning System (GPS) observations from 1994 to 2013. This re-processed dataset will provide high quality estimates of land motions, enabling regional and global high-precision geophysical/geodetic studies. Several of the individual TIGA Analysis Centres (TACs) have completed processing the full history of GPS observations recorded by the IGS global network, as well as, many other GPS stations at or close to tide gauges, which are available from the TIGA data centre at the University of La Rochelle (www.sonel.org). Following the recent improvements in processing models and strategies, this is the first complete reprocessing attempt by the BLT TIGA Analysis centre to provide homogeneous position time series. We report the quality of the multi-year daily solutions from the consortium of the British Isles continuous GNSS Facility (BIGF) and the University of Luxembourg TIGA Analysis Centres (BLT) based on the Bernese GNSS Software Version 5.2 using a double difference (DD) network processing strategy. [less ▲]

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See detailVariables associated to aging well in poor Peruvian older adults
Tournier, Isabelle UL; Olivera, Javier

Poster (2015)

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See detailTablet-based visuo-spatial training tool for preschoolers
Cornu, Véronique UL; Pazouki, Tahereh; Martin, Romain UL

Poster (2015)

In the context of numerical development, visuo-spatial skills are are assumed to provide an early foundation for later mathematical learning. First evidence for positive effects of visuo-spatial training ... [more ▼]

In the context of numerical development, visuo-spatial skills are are assumed to provide an early foundation for later mathematical learning. First evidence for positive effects of visuo-spatial training on numerical performance in children has recently been provided (Cheng & Mix, 2014). In sum, visuo-spatial training can be considered as being a promising approach for enhancing young children’s early math performance and providing them with a sound foundation for later mathematical learning. Nevertheless, rarely any visuo-spatial training material is currently available for the preschool setting. Based on this, we have developed a tablet-based visual-spatial intervention tool for preschoolers. This tool has been specifically designed for the school setting and should be administered by a teacher to a whole classroom or a small group of children. In terms of design, the tablet workspace is conceptualized as an electronic blackboard being used in combination with external material such as booklets. A multitude of tasks targeting different levels of visual-spatial abilities have been developed and will be presented. This tool is currently being scientifically evaluated in the context of a first classroom based intervention study in Luxembourgish kindergartens (N=125). In a pretest-posttest design, we are evaluating changes in visuo-spatial abilities and potential transfer effects on numerical abilities in the intervention group (n=68) compared to a “teaching as usual” control group (n=57). The intervention is carried out twice per week (20 minutes per session) over a period of 10 weeks. Only near transfer effects could be observed, but no further transfer to non-trained transformation skills and early math abilities. Training effects were thus restricted to skills that have been specifically targeted during training sessions. [less ▲]

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See detailHorizontal tuning of face-specific processing from childhood to elderly adulthood.
Goffaux, Valerie; Poncin, Aude; Schiltz, Christine UL

Poster (2015)

Face recognition in adults recruits specialised mechanisms that are selectively driven by horizontal information. This range indeed conveys the most optimal and stable cues to identity. Whether the ... [more ▼]

Face recognition in adults recruits specialised mechanisms that are selectively driven by horizontal information. This range indeed conveys the most optimal and stable cues to identity. Whether the horizontal tuning of adult face recognition reflects horizontal bias already active at infancy and/or whether it also results from the extensive experience acquired with faces over the lifespan is elusive. Answering these questions is crucial to determine the information constraining the developmental specialisation of core visual functions such as face perception. Participants aged between 6 and 74 years matched unfamiliar faces that were filtered to retain information in narrow ranges centred on horizontal (H), vertical (V), or both orientation ranges (HV). H and V ranges respectively maximize and minimize the recruitment of face-specific mechanisms (Goffaux and Dakin, 2010). Stimuli were presented at upright and inverted planar orientations and the face inversion effect (FIE; i.e., better performance for upright than inverted faces) was taken as a marker of face-specific processing. In H and HV conditions, FIE size increased linearly from childhood to adulthood, manifesting the progressive specialization of face perception. FIE emerged earlier when processing HV than H faces (FIE onset: 6 and 12 years, respectively) indicating that until 12 years horizontal information is necessary but not sufficient to trigger face-specialised processing. Partial correlations further showed that FIE development in HV condition was not fully explained by FIE development in H condition. Besides a progressive maturation of horizontal processing, the specialization of the face processing system thus also depends on the improved integration of horizontal range with other orientations. In contrast, FIE size was small and stable when processing V information. These results show that the face processing system matures over the life span based on the refined encoding of horizontally-oriented (upright) face cues. Meeting abstract presented at VSS 2015. [less ▲]

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See detailHigher response rates at the expense of validity? Consequences of the implementation of the ‘forced response‘ option within online surveys
Decieux, Jean Philippe Pierre UL; Mergener, Alexandra; Neufang, Kristina et al

Poster (2015)

Due to the low cost and the ability to reach thousands of people in a short amount of time, online surveys have become well established as a source of data for research. As a result, many non ... [more ▼]

Due to the low cost and the ability to reach thousands of people in a short amount of time, online surveys have become well established as a source of data for research. As a result, many non-professionals gather their data through online questionnaires, which are often of low quality due to having been operationalised poorly (Jacob/Heinz/Décieux 2013; Schnell/Hill/Esser 2011). A popular example for this is the ‘forced response‘ option, whose impact will be analysed within this research project. The ‘forced response’ option is commonly described as a possibility to force the respondent to give an answer to each question that is asked. In most of the online survey computer software, it is easily achieved by enabling a checkbox. Relevance: There has been a tremendous increase in the use of this option, however, the inquirers are often not aware of the possible consequences. In software manuals, this option is praised as a strategy that significantly reduces item non-response. In contrast, research studies offer many doubts that counter this strategy (Kaczmirek 2005, Peytchev/Crawford 2005, Dillman/Smyth/Christian 2009, Schnell/Hill/Esser 2011, Jacob/Heinz/Décieux 2013). They are based on the assumption that respondents typically have plausible reasons for not answering a question (such as not understanding the question; absence of an appropriate category; personal reasons e.g. privacy). Research Question: Our thesis is that forcing the respondents to select an answer might cause two scenarios: - Increasing unit non-response (increased dropout rates) - Decreasing validity of the answers (lying or random answers). Methods and Data: To analyse the consequences of the implementation of ‘forced response’ option, we use split ballot field experiments. Our analysis focuses especially on dropout rates and response behaviour. Our first split ballot experiment was carried out in July 2014 (n=1056) and we have planned a second experiment for February 2015, so that we will be able to present our results based on strong data evidence. First results: If the respondents are forced to answer each question, they will - cancel the study earlier and - choose more often the response category “No” (in terms of sensitive issues). [less ▲]

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See detailThe Good Side of Pride: When Being Proud Protects Us From Suggestions.
Schaan, Violetta UL; Walther, Eva

Poster (2015)

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See detailPraxisBüro BSSE
Böwen, Petra UL; Dujardin, Céline UL; Romberg, Kathrin

Poster (2015)

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See detailBT Quantization on K3 Surfaces
Castejon-Diaz, Hector UL

Poster (2015)

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See detailMother and father competence and child attachment representations in a sample of internationally adopted adolescents
Molina, Paola; Casonato, Marta; Ongari, Barbara et al

Poster (2015)

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See detailROS homeostasis in a dynamic model: How to save PD neuron?
Kolodkin, Alexey UL; Ignatenko, Andrew UL; Sangar, Vineet et al

Poster (2014, December)

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See detailReproducible Research Results R3
Trefois, Christophe UL; Jarosz, Yohan UL; Gu, Wei UL et al

Poster (2014, December)

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See detailRelaxation times and electron-phonon interaction in graphene quantum dots
Reichardt, Sven UL; Volk, Christian; Neumann, Christoph et al

Poster (2014, November 07)

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See detailCardiff/Luxembourg Computational Mechanics Research Group
Bordas, Stéphane UL; Kerfriden, Pierre; Hale, Jack UL et al

Poster (2014, November)

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See detailField-Induced Spin Helix Chirality in Nanocrystalline Ho
Szary, Philipp UL; Bick, Jens-Peter UL; Kaiser, Daniel UL et al

Poster (2014, November)

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See detailMagnetic properties of Ta/NdFeB core-shell microwires
Szary, Philipp UL; Luciu, Ioana; Duday, David et al

Poster (2014, November)

Detailed reference viewed: 70 (8 UL)