Marche et attention sélective chez les personnes âgées

Poster (2014, May)

Un lien entre troubles de la marche, chutes et fonction cognitives (fonctions exécutives et attention), chez les personnes âgées peut être considéré comme établi. En ce qui concerne les paramètres de la ... [more ▼]

Un lien entre troubles de la marche, chutes et fonction cognitives (fonctions exécutives et attention), chez les personnes âgées peut être considéré comme établi. En ce qui concerne les paramètres de la marche, une variabilité du pas élevée et un ralentissement de la vitesse de marche sous condition de double tâche, sont des indicateurs sensibles permettant d’évaluer le risque de chute. La présente étude s´est intéressée aux différences de ces paramètres de marche en fonction de la performance dans un test d´attention sélective. L´échantillon est composé de 33 personnes âgées en long séjour (âge moyen : 83.7, écart-type : 6.2). L´analyse de la marche a été effectué à l´aide du système Gaitrite® qui permet de mesurer e.a. la vitesse, la variabilité de la durée du cycle de marche et la variabilité de la longueur du cycle de marche. L´attention sélective a été mesurée avec un test d´attention sélective adapté aux personnes âgées. Les personnes ont été regroupées sur la base de leur performance dans ce test (temps requis et erreurs commises) afin d´obtenir deux groupes : un groupe plus performant et un groupe moins performant. On a pu observer des différences de marche en fonction de l´attention sélective. Plus précisément, dans le groupe moins performant considérant les erreurs commises lors du test, la variabilité de la longueur du cycle de marche sous condition double tâche était sifnificativement supérieure à celle du groupe plus performant (U = 175.0, p < .05). Ces résultats mettent en évidence les différences dans les paramètres de marche, et le risque de chute associé, en fonction de la capacité d´attention sélective chez les personnes âgées. [less ▲]

Integrated Omic Analyses of the Human Gut Microbiome in a Multiplex Family Study of Type 1 Diabetes Mellitus

Poster (2014, April 30)

Semi-empirical phonon calculations for graphene on different substrates

Poster (2014, April 02)

We investigate the graphene-substrate interaction via changes in the phonon dispersion of graphene. Ab-initio calculations on these systems are of high computational cost due to the non-commensurability ... [more ▼]

We investigate the graphene-substrate interaction via changes in the phonon dispersion of graphene. Ab-initio calculations on these systems are of high computational cost due to the non-commensurability of the unit cells of graphene and the substrate. This leads to the formation of Moiré patterns with accordingly large supercell sizes. We use a semi-empirical force constant model for the calculation of phonons of graphene on different metallic and insulating substrates. The interaction of graphene with the substrate is described via suitably chosen spring constants. The phonon dispersion in the primitive unit cell of graphene is obtained via an “unfolding procedure” similar to the ones used for the discussion of ARPES (angular resolved photo-emission spectroscopy) of graphene on incommensurate substrates. [less ▲]

Dynamic change of host gastrointestinal microbiome and immune status in relation to mucosal barrier effects during chemotherapy and immune ablative intervention in humans

Poster (2014, April)

The human gastrointestinal tract is colonized by communities of endogenous microbes, commonly referred to as the microbiome. Here, the microbiota are in close contact with the host intestinal mucosa and ... [more ▼]

The human gastrointestinal tract is colonized by communities of endogenous microbes, commonly referred to as the microbiome. Here, the microbiota are in close contact with the host intestinal mucosa and its innate and adaptive immune systems. The fact that certain stimuli induce an inflammatory response whereas others induce tolerance suggests, that the host immune system interacts with the microbiota and vice versa in different ways. However, the exact details of theses interactions remain largely unknown. It is known that cancer treatment can result in severe adverse effects like mucositis and in combination with allogeneic stem cell transplantation (Tx), in graft-versus host disease (GvHD). However, there is at present only sparse information available on the effects of chemotherapy on the intestinal microbiota and resulting changes in microbiome-immune system interactions. Almost no data exists on the effect of allogeneic stem cell Tx on the composition of the gastrointestinal microbiota. In this project, we are studying the complex interactions between the host and the intestinal microbiota after chemotherapy with or without allogeneic Tx and the occurrence of severe adverse side effects such as mucositis and GvHD. Using a systems biology approach including metagenomics and RNAseq, fecal samples and blood plasma samples from patients undergoing these treatments for malignancies will be analysed to identify the composition of the gastrointestinal microbiome and bacterial small RNAs. The main research hypothesis is that there are quantitative and qualitative changes in the gastrointestinal microbiome following chemotherapy and allogeneic Tx which are linked to the immune status of the patients and possible treatment side-effects, in particular mucositis and GvHD. We aim to provide knowledge on how the host's intestinal mucosa and immune system influence the gastrointestinal microbiome and on the role and involvement of the gastrointestinal microbiota in development in mucositis and GvHD. Importantly, this could help in the formulation of measures to prevent mucositis and GvHD development. [less ▲]

Field-induced spin helix chirality in nanocrystalline Ho

Poster (2014, April)

Developing a mathematics large-scale assessment at the beginning of first grade in Luxembourg

Poster (2014, April)

Gender differences in mathematics achievement in 3rd and 9th grade students: A large-scale study in Luxembourg.

Poster (2014, March 30)

Since 2009, ÉpStan (Épreuves Standardisées) is an annual large-scale study in Luxembourg. It aims to evaluate Luxembourg's school system, in particular students’ achieved competency level in mathematics ... [more ▼]

Since 2009, ÉpStan (Épreuves Standardisées) is an annual large-scale study in Luxembourg. It aims to evaluate Luxembourg's school system, in particular students’ achieved competency level in mathematics implemented in 3rd and 9th grade. The present study aims to investigate whether the existing gender gap in mathematics among 15-year-olds revealed by PISA 2012 can be confirmed in ÉpStan 9th grade and if it already exists in younger students’ mathematics performance (ÉpStan 3rd grade) (Robinson, & Theule Lubienski, 2011). Further, we study wether a gender gap in students’ drive, motivation and self-beliefs concerning mathematics performance exists. [less ▲]

Strain-induced low-frequency relaxation in colloidal DGEBA/SiO2 suspensions

Poster (2014, March)

Assimilation of zenith total delays in the AROME France convective scale model: a recent assessment

Poster (2014, February)

Gradient Smoothing for Nearly Incompressible Hyperelasticity

Poster (2014)

SLAPn: A Tool for slicing Algebraic Petri nets

Poster (2014)

Algebraic Petri nets is a well suited formalism to represent the behavior of concurrent and distributed systems by handling complex data. For the analysis of systems modelled in Algebraic Petri nets ... [more ▼]

Algebraic Petri nets is a well suited formalism to represent the behavior of concurrent and distributed systems by handling complex data. For the analysis of systems modelled in Algebraic Petri nets, model checking and testing are used commonly. Petri nets slicing is getting an attention recently to improve the analysis of systems modelled in Petri nets or Algebraic Petri nets. This work is oriented to define Algebraic Petri nets slicing and implement it in a verification tool. [less ▲]

Preservice teachers implicit and explicit attitudes and judgments of students with secial educational needs from different backgrounds

Poster (2014)

A 16S rRNA gene Illumina–based barcoded assay design for high throughput characterisation of microbial communities from anaerobic digesters

Poster (2014)

High throughput sequencing of 16S/18S rRNA gene is becoming an indispensable tool to explore microbial community ecology. To date, most of the studies using next generation amplicon sequencing of ... [more ▼]

High throughput sequencing of 16S/18S rRNA gene is becoming an indispensable tool to explore microbial community ecology. To date, most of the studies using next generation amplicon sequencing of microorganisms involved in the anaerobic digestion process (AD) are based on the 454 pyrosequencing. However, the cost per read obtained with the Illumina technology is currently less than 1/100 of that for the 454 pyrosequencing, thus enabling throughout sequencing and larger number of samples to be analysed per study (e.g. given the current Miseq output, around 100 000 reads per sample can be expected for a pool of 96 libraries). Moreover, the Illumina technology is less biased by the GC content of the template and currently allows for a relatively long sequence read of 600 bp (2 x 300bp). This consideration is particularly important, since longer sequences permit for more accurate assignment to a taxonomic group. Here, we designed and optimized an Illumina–based 16S rRNA amplicon approach for a high throughput characterization of microbial communities from different AD. [less ▲]

„For the Most Part, Teachers Are Very Friendly and Fair—But Not All of Them!“ Negative teacher behavior in the classroom.

Poster (2014)

Canonical finger numeral configurations are perceived holistically

Poster (2014)

Sooner or later human beings represent or see numerosities represented by hands. This handling of small numerosities by prototypical finger configurations has been the focus of many experiments ... [more ▼]

Sooner or later human beings represent or see numerosities represented by hands. This handling of small numerosities by prototypical finger configurations has been the focus of many experiments investigating the possibility that semantic representations of numbers are motor-rooted. Canonical finger configurations (i.e. the culturally determined way to express numerosity with fingers) are for instance recognized faster (Di Luca et al., 2006), and give direct access to number semantics (Di Luca et Pesenti, 2008). It is also known that these effects are not due to a visual facilitation of canonical configurations (Di Luca et Pesenti, 2010), but to a different inner representation (Di Luca, Lefèvre and Pesenti, 2010). However, a precise characterization of their visual processing is currently lacking. We addressed this shortcoming by using an eye-tracking method based on gaze-contingent stimulus presentation (Van Belle et al., 2010). While participants named numerosities expressed by canonical and non-canonical finger numeral configurations presented in upright or inverted orientations, we selectively impaired analytical or holistic visual perception by respectively masking (in real time) peripheral or focal vision. Our data confirm the results found in literature: canonical configurations are processed faster than non-canonical ones, upright configurations are processed faster than inverted ones and holistic perception is faster than analytical one. Most importantly, we also demonstrate that canonical configurations are impaired by the peripheral mask (i.e. holistic vision hindered) whereas non-canonical ones are impaired by the foveal mask (i.e. analytical vision hindered). These results confirm that the practice of finger numeral configurations modifies not only the way human beings process and represent numerosities but especially the way to visually perceive them. [less ▲]

The development of number symbol processing: A fast periodic visual stimulation study

Poster (2014)

In our cultures the meaning of number symbols is acquired and reinforced through education. Accordingly, it is critical to understand how children become experts in the use of Arabic numbers (AN). Here ... [more ▼]

In our cultures the meaning of number symbols is acquired and reinforced through education. Accordingly, it is critical to understand how children become experts in the use of Arabic numbers (AN). Here, we used fast periodic visual stimulation (FPVS) combined with a repetition-suppression paradigm (Rossion & Boremanse, 2011) to measure rapidly and objectively the sensitivity to symbolic numerical stimuli of 6-to-12-y.o. children (n=20) and adults (n=11). Participants were presented four sequences: two of AN and two of AN-like sham stimuli. Half of the sequences consisted of different stimuli (“10”, “18”, “12”,...), the other half of same stimuli (“10”) presented repeatedly. Stimuli appeared at 3.5 items/second (fundamental frequency=3.5 Hz), for 60 seconds. We observed a large increase of the EEG response at 3.5 Hz (a steady-state visual-evoked potential; Regan, 1966) over parieto-occipital electrodes. This response was larger during different than same sequences, especially when participants saw real (vs. sham) AN. The amplitude of this specific response to numbers increased with children’s age. Moreover its location changed from posterior occipital electrodes in childhood to more lateral parietal electrodes in adulthood. These results indicate that FPVS of AN is a promising tool to study the sensitivity to numerical magnitude in children and adults. [less ▲]

Promoting Equality: Social Work and CRPD

Poster (2014)

Performance Evaluation of an IaaS Opportunistic Cloud Computing

Poster (2014)

This poster shows the performance evaluation of UnaCloud Opportunistic Computing IaaS. We analyze from an HPC perspective, two virtualization frameworks Virtual Box and VMware ESXi and compare them over ... [more ▼]

This poster shows the performance evaluation of UnaCloud Opportunistic Computing IaaS. We analyze from an HPC perspective, two virtualization frameworks Virtual Box and VMware ESXi and compare them over this particular opportunistic cloud environment. The benchmarks consist of two set of tests, High Performance Linpack and IOzone, that examine the performance and the Input/Output response. The purpose of the experiments is to evaluate the behavior of the different virtual environments over an opportunistic cloud environment and investigate how these are affected by different percentage of end-users. The results show a better performance for Virtual Box than VMware and the other way around for I/O response. Nevertheless, the experiments shows that VBox have more robustness than VMware. [less ▲]

Recycle your stress! How the interpretation of acute stress influences blood pressure, cognitive performance and rumination

Poster (2014)

Reappraising arousal boosts efficient sympathetic activation and analytic performance. We investigated if mindful awareness of bodily changes without positive re-evaluation of this perception also helps ... [more ▼]

Reappraising arousal boosts efficient sympathetic activation and analytic performance. We investigated if mindful awareness of bodily changes without positive re-evaluation of this perception also helps to buffer against negative stress responses. Taken together the results suggest that both mindfulness and reappraisal influence stress-related blood pressure, working memory performance and rumination. [less ▲]

Trabalho Escravo and the Globalized World

Poster (2014)

Comparative Analysis of Real-Time Precise Point Positioning Zenith Total Delay Estimates

Poster (2013, December 13)

The use of observations from Global Navigation Satellite Systems (GNSS) in operational meteorology is increasing worldwide due to the continuous evolution of GNSS. The assimilation of near real-time (NRT ... [more ▼]

The use of observations from Global Navigation Satellite Systems (GNSS) in operational meteorology is increasing worldwide due to the continuous evolution of GNSS. The assimilation of near real-time (NRT) GNSS-derived zenith total delay (ZTD) estimates into local, regional and global scale numerical weather prediction (NWP) models is now in operation at a number of meteorological institutions. The development of NWP models with high update cycles for nowcasting and monitoring of extreme weather events in recent years, requires the estimation of ZTD with minimal latencies, i.e. from 5 to 10 minutes, while maintaining an adequate level of accuracy for these. The availability of real-time (RT) observations and products from the IGS RT service and associated analysis centers make it possible to compute precise point positioning (PPP) solutions in RT, which provide ZTD along with position estimates. This study presents a comparison of the RT ZTD estimates from three different PPP software packages (G-Nut/Tefnut, BNC2.7 and PPP-Wizard) to the state-of-the-art IGS Final Troposphere Product employing PPP in the Bernese GPS Software. Overall, the ZTD time series obtained by the software packages agree fairly well with the estimates following the variations of the other solutions, but showing various biases with the reference. After correction of these the RMS differences are at the order of 0.01 m. The application of PPP ambiguity resolution in one solution or the use of different RT product streams shows little impact on the ZTD estimates. [less ▲]

Social Inequality and the transition to retirement in Europe and the US

Poster (2013, November 28)

This study examines the transition to retirement in a comparative analysis. The intersection to retirement has been linked with diverse consequences in past research. On one side, studies find negative ... [more ▼]

This study examines the transition to retirement in a comparative analysis. The intersection to retirement has been linked with diverse consequences in past research. On one side, studies find negative effects on psychological well-being of retirement due to loss of employment, social networks and stability through work life. Others present results of a positive effect connected to pension. From a life course perspective, experiences in one’s employment history might impact the transition to and the retirement period itself. I hypothesize on the individual level that transition to retirement is influenced by working life experience and quality. The transition to retirement might be easier for people with a higher socio-economic status thus high education as well as financial resources. On the other hand, the experience of unemployment or lower job placement might cause depression or a decline of life satisfaction. The Theory of Cumulative Advantages and the mechanism of scarring propose that unemployment will have a long-life effect on the career. But is the effect even sustaining in old age? How does the transition to retirement influence life satisfaction and what impact has scarring? To answer these questions I will make use of SHARE and HRS longitudinal data on well-being of seniors and their socioeconomic situation and work history. The rich variation of countries in SHARE makes it possible to compare different welfare regimes. As SHARE lacks liberal countries, I will include the US to have a more consistent picture. [less ▲]

Accelerating short transfers in 802.11 networks

Poster (2013, November 14)

The legacy bandwidth discovery phase of TCP spends an unnecessary number of RTTs for reaching the fair share of the network. In this article we introduce a simple modification at the receiver that splits ... [more ▼]

The legacy bandwidth discovery phase of TCP spends an unnecessary number of RTTs for reaching the fair share of the network. In this article we introduce a simple modification at the receiver that splits the TCP ACKs in a controlled manner. This mechanism allows to fast ramp-up the TCP congestion window. Our experiments performed in a real testbed show benefits not only in the increased data throughput but also in a non-congested uplink (Acknowledgement) path in an 802.11 access. [less ▲]

German University-based Science: From Model to Contemporary Reality?

Poster (2013, November)

This QNRF-funded project features a cross-national investigation of the influence of higher education development and science capacity-building on scientific knowledge production. Measuring science on the ... [more ▼]

This QNRF-funded project features a cross-national investigation of the influence of higher education development and science capacity-building on scientific knowledge production. Measuring science on the basis of published papers in selected STEM disciplines, we identify factors behind national differences and global similarities. How does variation in national models and strategies to develop higher education and research universities explain long-term cross-national trajectories in science productivity over the 20th century? Observing unprecedented growth in scientific knowledge productivity, we selected six national cases that represent three phases of higher education development and science-based societies: a major European precursor model (Germany), American broad institutionalization of the currently dominant model, and, finally, Asian (Japan, China, Taiwan) and Middle Eastern (Qatar) innovators seeking to learn from the best. The enormous potential of a knowledge economy and society depends on continued production of scientific knowledge, but also its specification and enhanced quality. Even though scientists globally add to the world’s store of scientific knowledge, there are significant cross-national differences in relative contribution. While global production grows substantially, a few nations still produce the overwhelming majority of new science. For example, the U.S. leads the world in research, producing 21% of all research papers (2004-2008). Together with China (10%), UK (7%), Japan (6%) and Germany (6%), these five countries contribute 60% of all publications globally. Our preliminary research suggests that differences in key aspects of institutional models of higher education development and science capacity-building are associated with cross-national differences in scientific knowledge production over time. We use mixed-methods to analyze the institutional model of higher education development and science capacity-building in these nations over time. Our main measure is the number of published papers in journals, relying on a unique dataset from Thomson Reuters’ Web of Science (1900-2011). Examining trends in journal publications in selected STEM disciplines, we analyze how universities, investments in higher education and science, international collaborations, and scientific networks have changed to create the conditions for the “knowledge society”. Mainly, this poster presentation explains the influential German institutional model of the research university, which enjoyed preeminent status in modern science’s early institutionalization. Placing primacy on autonomous science and valorizing the unity of teaching and research, this type of university continues to dominate German higher education. Yet massive tertiary educational expansion, the rise of extra-university research institutes, and establishment of praxis-oriented universities of applied sciences challenge the foundational principle, threaten this globally popular model, and reduce university-based research capacity in Germany. Nevertheless, Germany’s dual pillars of mass universities and prestigious independent research institutes continue to boast one of the largest national scientific outputs globally. With an annual R&D investment of 2.84% GDP (2011), Germany has among the highest levels of science investment in Europe. Measured in publications, Germany still competes at the very top. While still a model for other countries, other top science countries today rely on their universities more in producing competitive science than does Germany. [less ▲]

The King Edward Point Geodetic Observatory in Support of Sea Level Research

Poster (2013, October 28)

During February 2013 the King Edward Point (KEP) Geodetic Observatory was established in South Geor- gia, South Atlantic Ocean, through a University of Luxembourg funded research project and in ... [more ▼]

During February 2013 the King Edward Point (KEP) Geodetic Observatory was established in South Geor- gia, South Atlantic Ocean, through a University of Luxembourg funded research project and in collaboration with the United Kingdom’s National Oceanography Centre, British Antarctic Survey and Unavco, Inc. Due to its remote location in the South Atlantic Ocean, as well as, being one of few subaerial exposures of the Scotia plate, South Georgia Island has been a key location for a number of global monitoring networks, e.g. seismic, geomagnetic and oceanic. However, no geodetic monitoring station has been established, e.g. by the International Global Navigation Satellite System (GNSS) Service (IGS) community, despite the lack of such observations from this region. In this study we give details of the establishment of the KEP Geodetic Observatory, i.e. the installation of the continuous GNSS station KEPA on Brown Mountain and the estab- lishment of a new height datum for the tide gauge through a network of benchmarks at the KEP research station. We will present an evaluation of the GNSS positioning results for the period from February to August 2013 and of the survey/levelling work carried out for the height reference. We will discuss the installation in terms of its potential contributions to sea level observations using tide gauges and satellite altimetry, studies of tectonics, glacio-isostatic adjustment and atmospheric processes. [less ▲]

Rumination, interoceptive awareness and suggestibility predict the occurrence of the thermal grill illusion

Poster (2013, October 10)

ruminationInterposed non-noxious cold and warm cutaneous stimuli applied via a thermal grill have repeatedly been shown to generate a paradoxical pain sensation, also described as ‘thermal grill illusion ... [more ▼]

ruminationInterposed non-noxious cold and warm cutaneous stimuli applied via a thermal grill have repeatedly been shown to generate a paradoxical pain sensation, also described as ‘thermal grill illusion of pain’. According to the ‘central disinhibition theory’ proposed by Craig and Bushnell [1], the pain phenomenon commonly qualified as burning can be explained by “an unmasking of cold-evoked activity of polymodal nociceptive lamina I spinothalamic neurons (activation by polymodal Cnociceptors) resulting from the reduction of normal coldevoked activity of thermoreceptive lamina I spinothalamic neurons (activation by Aδ cooling thermoreceptors) by spatial summation of the simultaneous warm stimuli in the thermoreceptive but not the nociceptive neurons.” Since a significant part of the tested subjects do however not display the thermal grill percept, it may be hypothesized that not only physiological-, but also psychological determinants play a crucial role in the generation of the paradoxical pain. Sad mood [2] and anxiety [3] have already been proposed as relevant psychological factors. The aim of the present research consisted in validating our custom made, water-driven and fMRI compatible thermal grill device [4], in identifying thermal grill ‘responders’ and ‘non-responders’ and in investigating whether different personality traits or states constitute predictors for the elicitation of the thermal grill illusion. [less ▲]

Estimation abilities of large numerosities in preschool children

Poster (2013, October)

The approximate number system (ANS) is thought to be a building block for the elaboration of formal mathematics. However, little is known about how this core system develops and if it can be influenced by ... [more ▼]

The approximate number system (ANS) is thought to be a building block for the elaboration of formal mathematics. However, little is known about how this core system develops and if it can be influenced by external factors at a young age (before the child enters formal numeracy education). The purpose of this study was to examine numerical magnitude representations of 5-6 year old children at 2 different moments of Kindergarten considering children's early number competence as well as schools' socio-economic index (SEI). This study investigated estimation abilities of large numerosities using symbolic and non-symbolic output formats (8-64). In addition, we assessed symbolic and non-symbolic early number competence (1-12) at the end of the 2nd (N = 42) and the 3rd (N = 32) Kindergarten grade. By letting children freely produce estimates we observed surprising estimation abilities at a very young age (from 5 year on) extending far beyond children's symbolic explicit knowledge. Moreover, the time of testing has an impact on the ANS accuracy since 3rd Kindergarteners were more precise in both estimation tasks. Additionally, children who presented better exact symbolic knowledge were also those with the most refined ANS. However, this was true only for 3rd Kindergarteners who were a few months from receiving math instructions. In a similar vein, higher SEI positively impacted only the oldest children's estimation abilities whereas it played a role for exact early number competences already in 2nd and 3rd graders. Our results support the view that approximate numerical representations are linked to exact number competence in young children before the start of formal math education and might thus serve as building blocks for mathematical knowledge. Since this core number system was also sensitive to external components such as the SEI this implies that it can most probably be targeted and refined through specific educational strategies from preschool on. [less ▲]

The exogenous RNA spectrum in human plasma and the gastrointestinal tract

Poster (2013, October)

Design principles study of ROS management and ROS-induced mitophagy with a kinetic model

Poster (2013, September 27)

In vivo evidence demonstrates three fundamental interconnected adaptive survival mechanisms , which protect against excessive ROS that is generated during mitochondrial dysfunction: (i) autophagy ... [more ▼]

In vivo evidence demonstrates three fundamental interconnected adaptive survival mechanisms , which protect against excessive ROS that is generated during mitochondrial dysfunction: (i) autophagy/mitophagy, (ii) adaptive antioxidant response and (iii) NFkB signaling in cancer and neurodegeneration. We have been expanding a kinetic model which recapitulates the consensus understanding of the mechanisms responsible for cellular ROS – management system and performed modular analysis to analyze emergent behavior. We started with the simplest model and added stepwise new modules. We identify the qualitative role (certain emergent behavior) attributed to each module and thus understand the design principles of the system. We propose a detailed, mechanistic, kinetic model for studying how mutations relevant for diseases such as PD and cancer affect the emergent behavior of ROS management network. [less ▲]

Potential Contributions to Geoscience from GNSS Observations of the King Edward Point Geodetic Observatory, South Georgia, South Atlantic Ocean

Poster (2013, September 01)

During February 2013 the King Edward Point (KEP) Geodetic Observatory was established in South Georgia, South Atlantic Ocean, through a University of Luxembourg funded research project and in ... [more ▼]

During February 2013 the King Edward Point (KEP) Geodetic Observatory was established in South Georgia, South Atlantic Ocean, through a University of Luxembourg funded research project and in collaboration with the United Kingdom’s National Oceanography Centre, British Antarctic Survey and Unavco, Inc. Due to its remote location in the South Atlantic Ocean, as well as, being one of few subaerial exposures of the Scotia plate, South Georgia Island has been a key location for a number of global monitoring networks, e.g. seismic, geomagnetic and oceanic. However, no geodetic monitoring station has been established, e.g. by the International Global Navigation Satellite System (GNSS) Service (IGS) community, despite the lack of such observations from this region. In this study we will present an evaluation of the GNSS observations from the KEP Geodetic Observatory for the period from February to August 2013. We calculate multipath and positioning statistics and compare these to those from IGS stations. The on-site meteorological data is compared to those from the nearby KEP meteorological station and global numerical weather models, and the impact of these data sets on delay and integrated water vapour estimates will be evaluated. We will discuss the installation in terms of its potential contributions to sea level observations using tide gauges and satellite altimetry, studies of tectonics, glacio-isostatic adjustment and atmospheric processes. [less ▲]

Effizienz gleich Leistung? Analyse des Antwortverhaltens bei einem distraktorfreien Matrizentest.

Poster (2013, September)

Anwendung effizienter Bearbeitungsstrategien abhängt. Bisherige Studien zeigen, dass strukturiertes und sequentielles Bearbeiten der Gestaltungsregeln nach aufsteigender Schwierigkeit zu einer besseren ... [more ▼]

Anwendung effizienter Bearbeitungsstrategien abhängt. Bisherige Studien zeigen, dass strukturiertes und sequentielles Bearbeiten der Gestaltungsregeln nach aufsteigender Schwierigkeit zu einer besseren Leistung führt. Während Bearbeitungsstrategien bislang durch Blickbewegungsstudien, Computersimulationen und die Methode des lauten Denkens ermittelt wurden, wurde in dieser Studie die Matrizenkonstruktionsaufgabe verwendet, bei der die Lösung in einer computerisierten Testumgebung generiert wird. Dies ermöglicht eine zeitgenaue und objektive Aufzeichnung des Prozesses der Antwortgenerierung. In Antwortprotokollen von 480 Probanden konnte mittels verschiedener Prozessindikatoren (Regelsprünge, Abweichung von erwarteter Bearbeitungsreihenfolge, Zurücksetzen generierter Lösungen, Ausmaß der Verwendung relevanter Gestaltungselemente) in einer multiplen Regression bis zu 28.8 % der Varianz der Testleistung aufgeklärt werden. Insbesondere strukturiertes und sequentielles Bearbeiten von Gestaltungsregeln sowie der Ausschluss irrelevanter Gestaltungselemente sind entscheidend für eine bessere Leistung. Entgegen bisheriger Befunde zeigt sich jedoch, dass die Bearbeitungsreihenfolge der Gestaltungsregeln nicht auf einer allgemeingültigen Schwierigkeit der Gestaltungsregeln beruht. [less ▲]

Effect of grafted alumina nanoparticles on thermal and dynamic mechanical properties of the styrene-butadiene rubber

Poster (2013, September)

Elastomers filled with hard nanoparticles are of great technical importance for the rubber industry. In general, fillers improve mechanical properties of polymer materials, e.g. elastic moduli, tensile ... [more ▼]

Elastomers filled with hard nanoparticles are of great technical importance for the rubber industry. In general, fillers improve mechanical properties of polymer materials, e.g. elastic moduli, tensile strength etc. The smaller the size of the particles the larger is the interface where interactions between polymer molecules and fillers can generate new properties. The aim of this contribution is to study the influence of the fillers’ surface treatment on the thermal and mechanical behavior of nanocomposites made of styrene-butadiene rubber (SBR). Three types of nanocomposites are investigated : (i) SBR-unmodified alumina, (ii) SBR – silanized alumina and (iii) SBR – alumina grafted to polymer chains. The surface-modified alumina nanoparticles were prepared using the method described in [1]. The grafting of the SBR chains to the alumina nanoparticles was realized by means of the procedures described in [2] and [3]. Temperature Modulated Differential Scanning Calorimetry (TMDSC) and Dynamic Mechanical Analysis (DMA) are well appropriated tools to investigate the thermal and dynamic glass transition behavior of the different nanocomposites, which is expected to be very sensitive to interfacial interactions between the nanoparticles and matrix molecules. TMDSC experiments reveal that all of the nanocomposites undergo a single glass transition. Thus, interphases induced by interfacial interactions do not manifest themselves by an additional glass transition unless it is hidden by the one of the matrix. Moreover, TMDSC measurements reveal that in general the glass transition temperature Tg depends in a complex manner on the concentration and surface treatment of the nanoparticles. The most important change of Tg is observed for the grafted nanocomposites: increasing the nanoparticle weight concentration beyond 4% yields an increase of Tg by 4 K. The corresponding slowing down of the molecular dynamics goes along with a significant decrease of the relaxator strength. More generally the presented results prove that, at the same filler concentration, the number of degrees of freedom freezing at the glass transition in case of un-grafted systems is practically independent on the chemical nature of the particles surface whereas it changes when there exist covalent bonds between the polymer molecules and the nanoparticles. DMA was used to probe the rheological behaviour of the nanocomposites under oscillatory shear. Isothermal frequency sweeps performed at different temperatures yield the real (G’) and imaginary (G”) parts of the complex shear modulus. Linear response regime conditions were strictly respected. The temperature-frequency equivalence principle was exploited to construct mastercurves for G’ and G” at the reference temperature T=273 K. As usual in polymers, three different behaviors were observed: the dynamic glass transition at high frequencies, the entanglement plateau at intermediary frequencies and viscoelastic “flowing” at very low frequencies. It generally appears that the filling of the SBR matrix with nanoparticles leads to an increase of the storage modulus that is more prominent in the rubbery region than in the glassy segment. While, in the low frequency regime, untreated and silanized alumina yield a mechanical behaviour that is rather near to the one of the neat SBR matrix, the grafting of elastomer molecules to the silanized fillers obviously induces a quasi-solid like response of the system. References: 1. Y.-Ch. Yang, S.-B. Jeong, B.-G. Kim, P.-R. Yoon, Powder Technology, 191, 117–121, 2009. 2. E. Passaglia, F. Donati, Polymer, 48, 35-42, 2007. 3. A. Bhattacharya, B. Misra, Prog. Polym. Sci. 29, 767–814, 2004. [less ▲]

Investigation of an integrative model of emotional competences: theoretical and methodological competences

Poster (2013, September)

Assessing the Status of GNSS Data Processing Systems to Estimate Integrated Water Vapour for Use in Numerical Weather Prediction models

Poster (2013, September)

Modern Numerical Weather Prediction (NWP) models make use of the GNSS derived Zenith Total Delay (ZTD) or Integrated Water Vapour (IWV) estimates to enhance the quality of their forecasts. Usually, the ... [more ▼]

Modern Numerical Weather Prediction (NWP) models make use of the GNSS derived Zenith Total Delay (ZTD) or Integrated Water Vapour (IWV) estimates to enhance the quality of their forecasts. Usually, the ZTD is assimilated into the NWP models on hourly intervals but with the advancement of NWP models towards higher update rates, it has become necessary to estimate the ZTD on sub-hourly intervals. In turn, this imposes requirements related to the timeliness and accuracy of the ZTD estimates and has lead to a development of various strategies to process GNSS observations to obtain ZTD with different latencies and accuracies. Using present GNSS products and tools, ZTD can be estimated in real-time (RT), near real-time (NRT) and post-processing (PP) modes. The aim of this study is to provide an overview and accuracy assessment of various RT, NRT, and PP IWV estimation systems and comparing their achieved accuracy with the user requirements for GNSS meteorology. The NRT and PP systems are based on the Bernese GNSS Software v5.2 using a double-difference network and Precise Point Positioning (PPP) strategy, and the RT systems are based on BKG Ntrip Client 2.7 and PPP-Wizard both using PPP. One of the RT systems allows integer ambiguity resolution with PPP and therefore the effect of fixing integer ambiguities on ZTD estimates will also be presented. [less ▲]

Fluctuation Relations and Crystallization

Poster (2013, August)

Hard Spheres undergo a fluid to solid phase transition if the packing fraction is approx. $>0.5$. The nucleation process itself and structure formation in this transient process are still under ... [more ▼]

Hard Spheres undergo a fluid to solid phase transition if the packing fraction is approx. $>0.5$. The nucleation process itself and structure formation in this transient process are still under investigation. Here a new approach is proposed to correlate forming structure and dissipation directly. Fluctuation relations are the method of choice. Increasing the pressure with time results in thermodynamic work, linked by the first law of thermodynamics to dissipation.\\ Studying fluctuation relations of structural phase transition and even slow dynamics is important. A new kind of fluctuation enters the dynamics that is macroscopic instead of microscopic based on thermal fluctuations. [less ▲]

Modeling cellular ROS defense in mitochondrial-related diseases

Poster (2013, July 22)

Reactive Oxygen Species (ROS) generation is an unavoidable background process during normal cellular function. The main contributor to ROS production is the electron transport chain, which reduces oxygen ... [more ▼]

Reactive Oxygen Species (ROS) generation is an unavoidable background process during normal cellular function. The main contributor to ROS production is the electron transport chain, which reduces oxygen to water. Some incompletely-reduced oxygen species escape and oxidize a variety of organic molecules, leading to molecular dysfunction and initiating a positive feedback loop of ever increasing active radical production. The increased concentration of ROS damages the mitochondria, therefore further elevating the rate of ROS generation. Healthy cells manage ROS enzymatically and by mitophagy of damaged mitochondria. The precise tuning of the latter mechanism is crucial for cell survival and is controlled by a ROS-induced regulatory network. We have built a set of kinetic models of varying complexity, based on the current understanding of the mechanism of cellular ROS defense. Our models allow simulation of various patho-physiological scenarios related to mitochondrial dysfunction and the failure of the system of ROS regulation in human cells. We employ the models we have constructed to simulate the effects of diseases related to mitochondrial dysfunction and excessive ROS generation, such as Parkinson’s disease, Huntington’s disease and cancer. Experimental evidence is used for model fitting, and we propose model improvements based on incorporation of single-cell experimental measurements. Finally, we discuss the perspective of integrating our kinetic models with genome-scale, constraint-based, tissue-specific models of metabolism, in order to study the effect of ROS misregulation on metabolic phenotype. [less ▲]

Cooperativity, geometrical constraints and slowed dynamics in glass-forming epoxy nanocomposites

Poster (2013, July)

Multilingual Teaching of Psychology: Does language matter?

Poster (2013, July)

Modifications of the Simpson moduli spaces of 1-dimensional sheaves on a projective plane by vector bundles

Poster (2013, June)

We study how to modify the Simpson moduli spaces of 1-dimensional coherent sheaves on a projective plane in order to obtain a space of vector bundles on curves.

Effects of sport club membership, sex, and age on physical self-concept and goal orientation in german primary school children

Poster (2013, June)

Mental disorders and personality characteristics in parents of patients with eating disorders

Poster (2013, May 25)

Spezifität der Körperbildstörung für Anorexia nervosa

Poster (2013, May 10)

Installation and First Evaluation of the King Edward Point Geodetic Observatory, South Georgia

Poster (2013, May)

During February 2013 the King Edward Point (KEP) Geodetic Observatory was established in South Georgia through a University of Luxembourg funded research project in collaboration with the National ... [more ▼]

During February 2013 the King Edward Point (KEP) Geodetic Observatory was established in South Georgia through a University of Luxembourg funded research project in collaboration with the National Oceanography Centre and the British Antarctic Survey. Due to its remote location in the South Atlantic Ocean as well as being one of few subaerial exposures of the Scotia plate, South Georgia has been a key location for a number of global monitoring networks, e.g. seismic, magnetic and oceanic. However, no geodetic monitoring station had been established previously despite the global network of Global Navigation Satellite System (GNSS) stations is lacking observations from this region. In this presentation we will present a first evaluation of the observations from the KEP Geodetic Observatory for the period from 14 February to 14 April 2013. We calculate multipath characteristics and positioning statistics from precise point positioning (PPP) and discuss the installation in terms of benefits for studies of tectonics and glacio-isostatic adjustment processes. The meteorological data is evaluated by comparison to the data from the existing KEP meteorological station and a widely used numerical weather model. [less ▲]

Récits de parents en situation vulnérable: Trajectoires de résilience familiale?

Poster (2013, May)

Dans la société actuelle, la famille est confrontée à plusieurs domaines d’action et politiques visant l’épanouissement familial et l’amélioration de la situation socio-économique et psycho-éducative ... [more ▼]

Dans la société actuelle, la famille est confrontée à plusieurs domaines d’action et politiques visant l’épanouissement familial et l’amélioration de la situation socio-économique et psycho-éducative, mais ceci en poursuivant différents objectifs à la fois. Dans ces domaines, nous retrouvons l’encouragement de l’emploi des femmes, la promotion de l’égalité des sexes, l’accueil de la petite enfance et l’école désirant entrer en partenariat éducatif, l’aide à l’enfance et à la famille proposant des soutiens à la parentalité etc. (cf. OCDE, 2011). Mais que vivent les parents bénéficiant d’une intervention socio-éducative quant à l’éducation des enfants ou quant aux difficultés intrafamiliales? L’étude qualitative communiquée se centre sur les récits de vie de parents en situation vulnérable dans le but de repérer leur élaboration de la notion de parentalité et d’éducation familiale. Plus spécifiquement, la recherche s’adresse aux difficultés rencontrées par les parents, aux réponses trouvées face aux difficultés parentales voire familiales, et aux trajectoires familiales contenant un développement favorable pour la famille. En outre, l'étude cherche à identifier des critères qualifiant les trajectoires familiales positives comme caractéristiques résilientes. Par ailleurs, nous examinons si le parent occupe un rôle central dans le processus de résilience familiale. Le raisonnement avec le concept de résilience familiale, c’est-à-dire la possibilité de trouver des résultats positifs préservant le développement de chaque membre et de l’unité familiale (Delage, 2010), nous permet de refléter les aspects favorables des trajectoires familiales, sans pour autant négliger les aspects vulnérables. [less ▲]

Executive functions in language-minority children with specific language impairment

Poster (2013, May)

This study explored executive function skills and language abilities in bilingual immigrant children with specific language impairment (SLI) from low income families in Luxembourg. Data from 81 eight-year ... [more ▼]

This study explored executive function skills and language abilities in bilingual immigrant children with specific language impairment (SLI) from low income families in Luxembourg. Data from 81 eight-year-olds from three different groups were analyzed: (1) 15 Portuguese-Luxembourgish children with SLI living in Luxembourg (Bi-SLI); (2) 33 typically developing Portuguese-Luxembourgish bilinguals from Luxembourg (Bi-TD); (3) 33 typically developing monolinguals from Portugal (Mo-TD). Groups were matched on first language, chronological age, and socioeconomic status, and did not differ in nonverbal intelligence. All children came from low income families and completed a range of measures tapping verbal and visuospatial working memory, selective attention, interference suppression and different domains of language (syntax and expressive and receptive vocabulary). Results indicate that despite large differences in their language scores (Bi-SLI < Bi-TD < Mo-TD), the groups exhibited comparable performance on the measures of visuospatial working memory, focused attention, and inhibitory suppression. Group differences emerged on the verbal working memory measures with Bi-SLI children performing significantly less well than the bilingual and monolingual typically developing groups that manifested comparable performance. The data suggests that: (a) children with SLI present verbal working memory limitations accompanied by preserved visuospatial executive functioning; (b) the measure that best discriminated the Bi-SLI group from their typically developing peers was the verbal working memory task digit recall. Practical implication for diagnosing SLI in bilingual children from disadvantaged social contexts will be discussed. [less ▲]

The influence of language on exact additions in bilingual adults.

Poster (2013, April)

To which degree is language involved in arithmetic? We investigated this question in a German-French bilingual setting. In Luxembourg, bilingualism is acquired through education: mathematics are taught in ... [more ▼]

To which degree is language involved in arithmetic? We investigated this question in a German-French bilingual setting. In Luxembourg, bilingualism is acquired through education: mathematics are taught in German in primary and in French in secondary school. Interestingly, the decades and units within two-digit number names follow the unit-decade order in German but the decade-unit order in French. Forty-eight bilingual adults performed simple and complex additions. Participants had to orally respond either in German or in French. Additions were presented in different conditions: (1) visual Arabic presentation, (2) auditory presentation (in German or in French), and (3) as a dual task in which visually presented additions were preceded by visually presented semantic judgments to indirectly activate a German or French language context. The results showed that participants performed complex calculations better in the dominant language (German), while there were no differences for simple calculations. Thus, language proficiency seems to be crucial for the computation of more complex calculations, whereas arithmetic facts can be retrieved equally well in both languages. Further, adding language at the input level (auditory presentation) enhanced performances for simple calculations, especially in the non-dominant language (French), while it was exactly the opposite effect for complex calculations. Additionally, visual additions were better performed within a surrounding linguistic context (3) than alone (1) in their non-dominant language, suggesting the crucial role of the linguistic context of an addition task in bilinguals. Taken together, these results support the view of a strong language impact on calculations. [less ▲]

Poverty and executive functions A latent variable study of children growing up in enriched and deprived conditions in Brazil

Poster (2013, April)

The Parkinson's Disease Map: A Framework for Integration, Curation and Exploration of Disease-related Pathways

Poster (2013, March 09)

Objectives: The pathogenesis of Parkinson's Disease (PD) is multi-factorial and age-related, implicating various genetic and environmental factors. It becomes increasingly important to develop new ... [more ▼]

Objectives: The pathogenesis of Parkinson's Disease (PD) is multi-factorial and age-related, implicating various genetic and environmental factors. It becomes increasingly important to develop new approaches to organize and explore the exploding knowledge of this field. Methods: The published knowledge on pathways implicated in PD, such as synaptic and mitochondrial dysfunction, alpha-synuclein pathobiology, failure of protein degradation systems and neuroinflammation has been organized and represented using CellDesigner. This repository has been linked to a framework of bioinformatics tools including text mining, database annotation, large-scale data integration and network analysis. The interface for online curation of the repository has been established using Payao tool. Results: We present the PD map, a computer-based knowledge repository, which includes molecular mechanisms of PD in a visually structured and standardized way. A bioinformatics framework that facilitates in-depth knowledge exploration, extraction and curation supports the map. We discuss the insights gained from PD map-driven text mining of a corpus of over 50 thousands full text PD-related papers, integration and visualization of gene expression in post mortem brain tissue of PD patients with the map, as well as results of network analysis. Conclusions: The knowledge repository of disease-related mechanisms provides a global insight into relationships between different pathways and allows considering a given pathology in a broad context. Enrichment with available text and bioinformatics databases as well as integration of experimental data supports better understanding of complex mechanisms of PD and formulation of novel research hypotheses. [less ▲]

The impact of inhibition capacities on number-space associations

Poster (2013, March 01)

Numerical and spatial representations are tightly linked (for a review see de Hevia et al., 2008). One specific instance of this link is the finding that when doing a binary classification judgment on ... [more ▼]

Numerical and spatial representations are tightly linked (for a review see de Hevia et al., 2008). One specific instance of this link is the finding that when doing a binary classification judgment on single Arabic digits, participants are faster to respond with their left/right hand to small/large numbers respectively. This observation has first been described by Dehaene and colleagues in the early 1990’s (Dehaene et al., 1993) and termed the SNARC effect (Spatial Numerical Association of Response Codes). Celebrating its 20th anniversary this year, the SNARC effect has been extensively replicated (for a meta-analysis see Wood et al., 2008) but one of its characteristics remains its high inter-individual variability (Wood et al., 2006a; 2006b). The source of this variability can partly be ascribed to differences in mathematical proficiency (Hoffmann et al., submitted) but a more domain general hypothesis implicating general inhibition capacities warrants further investigation. For the present study a total of 77 participants have been evaluated with a SNARC paradigm as well as standard inhibition tests (Stroop, Incompatibility subtest of the TAP test). Results show that when age-appropriate inhibition tests are used, inhibition capacities are strongly correlated with the SNARC effect, in the way that very efficient inhibition capacities lead to weaker SNARC effects. Consequently this finding could at least partly explain the impact of arithmetical proficiency on the SNARC effect. A study combining both measures would be an appropriate next step. [less ▲]

Thermal and mechanical properties of styrene butadiene rubber/alumina nanocomposites

Poster (2013, March)

SBR is a rubber material with high technical relevance. In order to enhance the mechanical properties of the rubber one method consists e. g. in dispersing inorganic nanoparticles in the polymer matrix ... [more ▼]

SBR is a rubber material with high technical relevance. In order to enhance the mechanical properties of the rubber one method consists e. g. in dispersing inorganic nanoparticles in the polymer matrix. By doing so, the properties of a given composite can be tuned either by changing the nanoparticle concentration or by modifying the surface properties of the fillers. Both interventions have indeed the potential to take influence on the structure and properties of the interphases emerging between the fillers and the polymer matrix. In this contribution we report on the glass transition behavior of SBR/alumina nanocomposites when the concentration and surface properties of the Al2O3 nanoparticles are changed. We also discuss the influence of the fillers on the shear stiffness of the rubber material. The samples were investigated by temperature modulated differential scanning calorimetry (TMDSC) and dynamic mechanical analysis (DMA). TMDSC investigations shed light on a surprising behavior of the glass transition temperature when the nanoparticle concentration is changed: at low filler contents the quasi-static glass transition temperature Tg passes through a minimum. While further increasing the nanoparticle content Tg increases to finally saturate at high concentrations. One of the main DMA results is that increasing of the Al2O3 concentration induces a quasi-solid-like frequency-independent response of the nanocomposites in the low frequency regime. [less ▲]