Defects in Cu(In,Ga)Se2: Photoluminescence vs Theory

Poster (2018)

Executive functions as moderators of the worked example effect on statistical reasoning. A replication study

Poster (2018)

A Reduced Order Kalman Filter for Computational Fluid-Dynamics Applications

Poster (2018)

Cross-border vocational education and training as a process of cross-border learning. The example of the Saarland-Lorraine border region

Poster (2018)

Cross-border vocational education and training (VET) becomes more and more important in the Saarland (DE)-Lorraine (FR) border region – even if so far there is only a small number of cases. It may be a ... [more ▼]

Cross-border vocational education and training (VET) becomes more and more important in the Saarland (DE)-Lorraine (FR) border region – even if so far there is only a small number of cases. It may be a solution for high youth unemployment rates in Lorraine and difficulties to find appropriated apprentices in Saarland. The main research questions of the research project are: 1. How does cross-border VET develop since the introduction of the Framework agreement on cross-border vocational and further training Saarland/Lorraine in 2014? 2. Which learning processes are related with the development of cross-border VET? [less ▲]

CFD Simulations of Adiabatic Boiling in Different Riser Geometries

Poster (2018)

The low-dimensional algebraic cohomology of the Witt and the Virasoro algebra

Poster (2018)

Poster: Performance Evaluation of an Open-Source Audio-Video Bridging/Time-Sensitive Networking Testbed for Automotive Ethernet

Poster (2018)

Automotive Ethernet (AE) is becoming more and more relevant to the automotive industry due to its support of emerging in-car applications, which have high bandwidth demands and stringent requirements in ... [more ▼]

Automotive Ethernet (AE) is becoming more and more relevant to the automotive industry due to its support of emerging in-car applications, which have high bandwidth demands and stringent requirements in terms of latency and time synchronization. One of the standards under consideration for AE is IEEE 802.1 Audio Video Bridging (AVB)/Time Sensitive Networking (TSN) that provides deterministic data link layer and bounded latency to real-time traffic classes. So far, this protocol stack has only been evaluated using either simulations or proprietary and expensive platforms. In this paper, we design a real testbed system for AE using general-purpose single-board computers and conduct experiments to assess the real-time performance of an open-source AVB/TSN implementation. Our preliminary results show that even under heavy load, AVB/TSN can fulfil the latency requirements of AE while keeping a constant latency variation. [less ▲]

First Vertical Land Movement Estimates on South Georgia Island: An Impact Study on Sea Level Change from Tide Gauge and Altimetry Measurements

Poster (2017, December 11)

South Georgia Island in the Southern Atlantic Ocean has been a key location for the seismic, geomagnetic and oceanic global monitoring networks. However, no permanent geodetic monitoring station had been ... [more ▼]

South Georgia Island in the Southern Atlantic Ocean has been a key location for the seismic, geomagnetic and oceanic global monitoring networks. However, no permanent geodetic monitoring station had been established there despite the lack of observations from this region within, for example, the International GNSS Service (IGS) network of Global Navigation Satellite System (GNSS) stations. Then, in 2013 the King Edward Point (KEP) Geodetic Observatory was established with a focus on sea level studies and in support of general geoscience applications. Currently, this observatory located roughly half-way along the main island and along its northern coastline, consists of two GNSS stations (KEPA and KRSA) with local benchmark networks, allowing the height determinations from the GNSS antennas to be transferred to the KEP tide gauge (GLOSS ID 187) and forming a height reference within the International Terrestrial Reference Frame. In late 2014, three additional GNSS stations (SG01, SG02 and SG03) were established, all on small islands at the perimeter of the main island. Together the stations provide the best possible opportunity to study various geophysical processes in the region. With the GNSS-derived position time series partly reaching over 4.5 years in length, it has become possible to provide first estimates of vertical land movements for the island and KEP with its surrounding area. Together with four precise levelling campaigns of the benchmark network in 2013, 2014 and two in 2017, it has also been possible to investigate the very local character of the vertical motions, ie. the stability of the jetty upon which the tide gauge is mounted. Our measurements show that while South Georgia Island and the area around KEP are rising, the jetty and tide gauge are subsiding. In this study, we will present the preliminary results from the GNSS and levelling measurements and will discuss their impact on the sea level record from the KEP tide gauge which is ideally situated in a mid-ocean location for satellite altimetry calibration over the Southern Atlantic and Southern Oceans. [less ▲]

Early life stress reduces neuropathic pain in adulthood -is alteration of spinal microglial reactivity critically involved?

Poster (2017, November 14)

Growing evidence underlines the association between early life adversity and persistent alterations of neural, endocrine and immune functions that may be accompanied by a host of disease patterns such as ... [more ▼]

Growing evidence underlines the association between early life adversity and persistent alterations of neural, endocrine and immune functions that may be accompanied by a host of disease patterns such as chronic pain in later life. Neuropathy is a debilitating condition presenting a substantial cooccurrence with stress related disorders. Despite the established overlapping of biochemical pathways involved in the etiology of these disorders, the intricacy of their mutual interdependence remains. In this context, immunocompetent cells are largely affected during chronic stress and are a key factor in the sensitization of nociceptive dorsal horn neurons. The goal of the present study was to investigate the impact of maternal separation (MS), a wellestablished model of early life stress in rodents, on chronic constriction injury (CCI)induced neuropathic pain and to reveal the relevance of spinal microglia activation and proinflammatory cytokine regulation. For this purpose 12 groups of rats were exposed to different combinations of stress condition, CCIinjury and pharmacological treatment. Noxious sensitivity was tested during baseline conditions as well as during subsequent neuropathic and pharmacological treatment conditions. Von Frey hair and the cold plate tests were used for the assessment of mechanical and cold hyperalgesia/allodynia. Amphotericin B, a substance known to activate monocytes and macrophages in the periphery and microglial cells in the CNS was administered to subgroups of animals. At the end of the protocol, rats were sacrificed to assess microglial activation using qPCR and immunohistochemistry. Our main finding was that maternal separation led to a reduction of CCIrelated pain hypersensitivity (thermal and mechanical hyperalgesia/allodynia). We concomitantly observed a downregulation of Iba 1, mRNA a marker of microglial cells, and of IL1β mRNA, a proinflammatory cytokine that may be released by microglia. According to preliminary results, Amphotericin B in turn seemed to enhance CCI related pain sensitivity, possibly via an activation of microglia. Our results show that MS may lead to a reduction of neuropathy relatedpain in adult age. Stress related dampening of spinal microglial reactivity may play a critical role in this context. [less ▲]

Reliable Machine Learning for Networking: Key Concerns and Approaches

Poster (2017, October)

Machine learning has become one of the go-to methods for solving problems in the field of networking. This development is driven by data availability in large-scale networks and the commodification of ... [more ▼]

Machine learning has become one of the go-to methods for solving problems in the field of networking. This development is driven by data availability in large-scale networks and the commodification of machine learning frameworks. While this makes it easier for researchers to implement and deploy machine learning solutions on networks quickly, there are a number of vital factors to account for when using machine learning as an approach to a problem in networking and translate testing performance to real networks deployments successfully. This paper, rather than presenting a particular technical result, discusses the necessary considerations to obtain good results when using machine learning to analyze network-related data. [less ▲]

Development of an innovative type of shear connection dedicated to the composite columns application

Poster (2017, September 13)

Avatar Sex Moderates Aggression in Violent Video Games, But Only for Women

Poster (2017, September 07)

Three studies tested findings reported by Yang, Huesmann, and Bushman (2014) that playing a male avatar in a violent video game leads to greater aggression than playing a female avatar in the same game ... [more ▼]

Three studies tested findings reported by Yang, Huesmann, and Bushman (2014) that playing a male avatar in a violent video game leads to greater aggression than playing a female avatar in the same game. The male avatar effect was confirmed in Study 1 (N=79) for post-game aggression: compared to playing a female character, participants who had played the male fighter in a violent mixed martials arts game chose more Hot Sauce for another participant who allegedly disliked spicy food. In contrast to Yang et al. (2014), however, the male avatar effect was qualified by participant sex, indicating that the effect was more strongly pronounced and only significant for female participants. A similar interaction effect was observed in Study 2 (N=76) and Study 3 (N=70) for in-game aggression: only female participants playing a male avatar showed a greater hit ratio in a mixed martials arts game (Study 2) or a greater number of attacks in a brawler game (Study 3) than their colleagues who played a female avatar. At this stage, the reason for this cross-gender effect is unclear. Given that games allow for behavior (i.e., aggression) independent of socially shared gender norms, we may speculate that for women, male avatars may provide the opportunity to “step out” of prevailing social norms regarding non-aggressive female behavior and adopt the role of the (hyper-)aggressive male. However, this hypothesis needs to be tested in future studies. All three studies additionally tested the mediating effect of male gender stereotype activation that was hypothesized by Yang et al. (2014). In addition to priming violent behavior, and in line with the General Aggression Model, the authors had speculated that playing the male avatar automatically activated male gender stereotypes (i.e., aggressive thoughts and behavior) which then caused aggressive behavior. In order to address this activation hypothesis, we designed an indirect cognitive measure of gender role identity using the Positive-Negative Sex-Role Inventory (PN-SRI: Berger & Krahé, 2013). After participants played the violent game, positive and negative aspects of masculinity and femininity were presented as word fragments in a five-minute response window in Study 1 and 2. Fragment completion rates served as indicators of cognitive activation of male stereotypes. In Study 3, participants used the intact PN-SRI gender attributes to rate the avatar after playing the game. However, both direct and indirect measures failed to corroborate the stereotype activation hypothesis in the present studies: word fragments related to male stereotypes were not completed more often than fragments related to female stereotypes (Study 1 and 2). Also, neither in-game aggression nor success in the game was associated with how masculine participants perceived their fighter (Study 3). At the present stage, thus, the mechanisms underlying the gender effect that participants respond differently when playing a male or female avatar in a violent video game remain unclear. [less ▲]

The relevance of verbal and visuo-spatial abilities for verbal number skills – what matters in 5 to 6 year olds?

Poster (2017, September)

The acquisition of verbal number skills, as defined by the meaningful use of number words, marks a milestone in numerical development. In the present study, we were particularly interested in the question ... [more ▼]

The acquisition of verbal number skills, as defined by the meaningful use of number words, marks a milestone in numerical development. In the present study, we were particularly interested in the question, whether verbal number skills are primarily verbal in nature, or if they call upon visuo-spatial processes, reflecting a spatial grounding of verbal number skills. 141 five- to six-year old children were tested on a range of verbal (i.e. vocabulary, phonological awareness and verbal working memory) and visuo-spatial abilities (i.e. spatial perception, visuo-motor integration and visuo-spatial working memory). We were particularly interested in the predictive role of these abilities for children’s verbal number skills (as measured by different counting and number naming tasks). In a latent regression model, basic visuo-spatial abilities, measured by spatial perception and visuo-motor integration, emerge as the most important predictor of verbal number skills. This gives raise to the assumption, that verbal number skills are, despite their verbal nature, spatially grounded in young children. [less ▲]

Influences of acute stress on inhibitory control - does age matter? An ERP study

Poster (2017, September)

Prefrontal cortex (PFC) based cognitive functions have been shown to be impaired with increasing age. Furthermore, the PFC has been found to be highly sensitive to stress and the stress hormone cortisol ... [more ▼]

Prefrontal cortex (PFC) based cognitive functions have been shown to be impaired with increasing age. Furthermore, the PFC has been found to be highly sensitive to stress and the stress hormone cortisol, which are assumed to influence executive functions. Although stress, allegorical for the life in the 21st century, concerns and affects both the young and the elderly in work life, little is known about the mutual impact of stress and aging on executive functioning. The present EEG study investigated the impact of acute stress on the core executive function inhibitory control in young and older males. Forty-nine participants were either stressed via the Trier Social Stress Test or underwent a control condition. Subse- quently, they performed a Go Nogo task while EEG, reaction times, errors and salivary cortisol were measured. Though older participants reacted slower to Go stimuli relative to young participants, both groups showed the same accuracy rate for Go and Nogo stimuli. Surprisingly, stress improved accuracy compared to the control group. The similar pattern was found in the EEG data with an enhanced error-related negativity (Ne/ERN) in the stress group. Beside this, elderly showed a reduced Ne compared to the young. No interaction between stress and age was observed. The present results suggest that stress may have beneficial effects on inhibitory control and error monitoring, irrespectively of the age. However, fur- ther research is needed to clarify if this is valid for other executive functions and under which circumstances negative impacts manifest. [less ▲]

Erloubet mir die selben vart. Episodisches Erzählen hoch zu Ross und in der Luft. Mittelalterliche und moderne Helden auf Aventiure-Fahrt

Poster (2017, September)

Update on national policy relating to the digital literacy and multimodal practices of young children

Poster (2017, August 31)

Tax Challenges of the Digital Economy - Taxation of Personal Data in the E-Economy

Poster (2017, August)

Human in the Loop: Interactive Passive Automata Learning via Evidence-Driven State-Merging Algorithms

Poster (2017, August)

We present an interactive version of an evidence-driven state-merging (EDSM) algorithm for learning variants of finite state automata. Learning these automata often amounts to recovering or reverse ... [more ▼]

We present an interactive version of an evidence-driven state-merging (EDSM) algorithm for learning variants of finite state automata. Learning these automata often amounts to recovering or reverse engineering the model generating the data despite noisy, incomplete, or imperfectly sampled data sources rather than optimizing a purely numeric target function. Domain expertise and human knowledge about the target domain can guide this process, and typically is captured in parameter settings. Often, domain expertise is subconscious and not expressed explicitly. Directly interacting with the learning algorithm makes it easier to utilize this knowledge effectively. [less ▲]

How the Mindfulness Concept Could Benefit the Caregiving of Older Adults

Poster (2017, July 23)

A Global Vertical Land Movement Data Set from a Combination of Global Navigation Satellite System Solutions

Poster (2017, July 13)

Coastal sea-level measurements by tide gauges provide the longest instrumental records of sea-levels with some stretching from the 19th century to present. The derived mean sea-level (MSL) records provide ... [more ▼]

Coastal sea-level measurements by tide gauges provide the longest instrumental records of sea-levels with some stretching from the 19th century to present. The derived mean sea-level (MSL) records provide sea-level relative to a nearby tide gauge benchmark (TGBM), which allows for the continuation of this record in time after, for example, equipment modifications. Any changes in the benchmark levels induced by vertical land movements (VLM) affect the MSL records and hence the computed sea-levels. In the past, MSL records affected by VLM were often excluded from further analyses or the VLM were modelled using numerical models of the glacial isostatic adjustment (GIA) process. Over the last two decades Global Navigation Satellite System (GNSS), in particular Global Positioning System (GPS), measurements at or close to tide gauges and the development of the associated processing strategies, have made it possible to obtain estimates of VLM in a geocentric reference system, such as the International Terrestrial Reference Frame release 2008 (ITRF2008) that approach the required accuracy for sea-level studies. Furthermore, the GPS-derived VLM estimates have been shown to improve estimates of sea-level change compared to those using the aforementioned GIA models as these models cannot predict local subsidence or uplift. The International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group has recently re-processed the global GNSS data set from its archive (1000+ stations for 1995-2014) to provide VLM estimates tuned for the sea-level community. To achieve this, five TIGA Analysis Centers (TAC) contributed their reprocessed global GPS network solutions to the WG, all employing the latest bias models and processing strategies in accordance with the second re-processing compaign (repro2) of the IGS. These individual solutions were then combined by the TIGA Combination Center (TCC) to produce, for the first time, a TIGA combined solution (Release 0.99). This combined solution allows an evaluation of each individual TAC solution while also providing a means to gauge the quality and reliability of the combined solution, which is generally regarded as superior to the individual TAC solutions. Using time series analysis methods, estimates of VLM can then be derived from the daily position estimates, which are sub-sequentially employed to investigate coastal sea-levels. In this study, we show results from the evaluation of the relevant solutions, provide an evaluation of the TIGA VLM estimates and give examples of their impact on sea-level estimates for selected tide gauges from around the world. The TAC and TIGA combined solutions, as well as the derived VLM data sets are available from the IGS TIGA WG and will be accessible through SONEL (www.sonel.org) in the near future. [less ▲]

Luxembourgish national identity and natives’ perception of immigrants

Poster (2017, July)

Migration is an important issue nowadays even more so in the light of the growing antimigrant attitudes we are currently witnessing all over the world. Luxemburg’s history, as many other countries, is ... [more ▼]

Migration is an important issue nowadays even more so in the light of the growing antimigrant attitudes we are currently witnessing all over the world. Luxemburg’s history, as many other countries, is also shaped by important migration waves as well as a growing national consciousness. It is therefore crucial to delve deeper into the way foreigners are perceived by natives in countries with dense immigrant populations. In the present study, we will have a closer look on the perceived threat from Luxembourgish natives’ viewpoint (N = 227; Mage = 37.2, SD = 14.9; range: 16-74; 59% of girls) regarding immigrants in general that could in a long-term perspective favour hostile attitudes towards foreigners. First analyses have showed that commitment to the own national identity, sense of security, satisfaction with current life and a higher proportion of non-Luxembourgish individuals within the circle of friends and own family are related with a lower perceived threat. [less ▲]

Deniability in Quantum Cryptography

Poster (2017, June 14)

This poster describes ongoing work on deniability in quantum cryptography, an area of research that remains almost entirely unexplored in the quantum information processing literature. Deniability is a ... [more ▼]

This poster describes ongoing work on deniability in quantum cryptography, an area of research that remains almost entirely unexplored in the quantum information processing literature. Deniability is a well-known and fundamental concept in classical cryptography and it can be defined as the ability for the sender of a message to deny the contents of a message or the very act of having participated in an exchange, e.g. having sent the said message. We discuss deniability in the context of quantum key exchange and address a particular problem, first discovered by Donald Beaver, where he claims that all QKD protocols are undeniable. The claim is that while we do get a one-time pad (OTP) using QKD, it does not provide the property of key equivocation as it is expected in the Shannon sense for a OTP. Intuitively, this difficulty lies in the quantum channel alone and it has to do with the fact that in QKD, while we generate entropy by expanding an initially short pre-shared key into an arbitrary longer secret key, we do so by exchanging information over a quantum as well as a classical channel, which could potentially leave a binding transcript of Alice's decisions to the final secret key. This is in contrast with the implicit assumption that Eve knows nothing about how two given parties have established their shared OTP in the first place. We discuss the importance of deniability in cryptography and its wide range of applications, along with cryptographic primitives other than key exchange where deniability might be a desired property. Finally, we present a series of fundamental open questions in this area of research and discuss quantum cryptographic primitives that lend themselves to devising deniable protocols. [less ▲]

Poster: Impact of ground truth errors on Wi-Fi localization accuracy

Poster (2017, June)

This study investigates the impact of small ground truth (GT) errors on indoor positioning systems based on Wi-Fi fingerprinting. The results demonstrate that even centimeter-scale GT deviations cause ... [more ▼]

This study investigates the impact of small ground truth (GT) errors on indoor positioning systems based on Wi-Fi fingerprinting. The results demonstrate that even centimeter-scale GT deviations cause severe degradation of measured localization accuracy. [less ▲]

Project NUMTEST: Assessing basic number competence without language

Poster (2017, May 31)

While numerical skills are fundamental in modern societies, some estimated 5-7% of children suffer from a mathematical learning disorder, called developmental dyscalculia (DD). Nevertheless, universally ... [more ▼]

While numerical skills are fundamental in modern societies, some estimated 5-7% of children suffer from a mathematical learning disorder, called developmental dyscalculia (DD). Nevertheless, universally valid diagnostic instruments are still lacking, as all current DD test batteries are based on language instructions. Consequently, their measurements are tightly linked to the specific language context of test administration and thus their results cannot easily be compared across countries. Here we are showing results of the first pilot study of a research project that aims to develop a test for basic math abilities that does not rely on language instruction and minimizes language use. To this aim, video and animation based instructions were implemented on touchscreen devices. A first version of the tasks has been tested with two samples of first grade children in Luxembourg’s fundamental schools, of which half completed the same tasks with traditional verbal instructions. Our results indicate that performance in the experimental group was similar or better than the control group using verbal instructions. Relationships between linguistic background and the sample’s performance on one hand and qualitative usability aspects of nonverbal task instruction and tablet-pc use with young children will be discussed. [less ▲]

A PetriNet Mechanism for OLAP in NUMA

Poster (2017, May 15)

Understanding Android App Piggybacking

Poster (2017, May)

The Android packaging model offers adequate opportunities for attackers to inject malicious code into popular benign apps, attempting to develop new malicious apps that can then be easily spread to a ... [more ▼]

The Android packaging model offers adequate opportunities for attackers to inject malicious code into popular benign apps, attempting to develop new malicious apps that can then be easily spread to a large user base. Despite the fact that the literature has already presented a number of tools to detect piggybacked apps, there is still lacking a comprehensive investigation on the piggybacking processes. To fill this gap, in this work, we collect a large set of benign/piggybacked app pairs that can be taken as benchmark apps for further investigation. We manually look into these benchmark pairs for understanding the characteristics of piggybacking apps and eventually we report 20 interesting findings. We expect these findings to initiate new research directions such as practical and scalable piggybacked app detection, explainable malware detection, and malicious code location. [less ▲]

Evaluation of ERA-Interim for tropospheric delay and water vapour estimation in different climate zones using ground-based GNSS observations

Poster (2017, April 27)

Tropospheric delay and integrated water vapour (IWV) derived from climate reanalysis models, such as that of the European Centre for Medium-range Weather Forecasts (ECMWF) namely the ECMWF ReAnalysis ... [more ▼]

Tropospheric delay and integrated water vapour (IWV) derived from climate reanalysis models, such as that of the European Centre for Medium-range Weather Forecasts (ECMWF) namely the ECMWF ReAnalysis-Interim (ERA-Interim), are widely used in many geodetic and atmospheric applications. Therefore, it is of interest to assess the quality of these reanalysis products using available observations. Observations from Global Navigation Satellite Systems (GNSS) are, as of now, available for a period of over 2 decades and their global availability make it possible to validate the zenith total delay (ZTD) and IWV obtained from climate reanalysis models in different geographical and climatic regions. In this study, a 5-year long homogeneously reprocessed GNSS data set based on double differenced positioning strategy and containing over 400 globally distributed ground-based GNSS stations has been used as a reference to validate the ZTD estimates obtained from the ERA-Interim climate reanalysis model in 25 different climate zones. It has been studied how the difference between the ERA-Interim ZTD and the GNSS-derived ZTD varies with respect to the different climate zones as well as the topographic variations in a particular climate zone. Periodicity in the ZTD residuals in different climate zones has been analyzed. Furthermore, the variation of the ZTD differences with respect to latitude has been presented. Finally, for one GNSS station in each of the 25 climate zones, IWV derived from ERA-Interim has been compared to the IWV derived using GNSS observations. [less ▲]

Mechanical characterisation of alkali activated clay - based geopolymer binder made out of gravel wash mud

Poster (2017, April 03)

One of the most promising cement alternatives are geopolymer cements. The term “geopolymer” was mentioned for the first time by Davidovits and classifies all forms of inorganic polymeric material ... [more ▼]

One of the most promising cement alternatives are geopolymer cements. The term “geopolymer” was mentioned for the first time by Davidovits and classifies all forms of inorganic polymeric material synthesised by chemical reaction of aluminosilicates and an alkaline activating solution. The production of geopolymer binder comprises in two main procedures: calcination and geopolymerisation. The synthesised geopolymer shows interesting characteristics like good mechanical properties, high strength and good durability. [less ▲]

The influence of Forced Answering on response behavior in Online Surveys: A reactance effect?

Poster (2017, March 16)

Relevance: Recent studies have shown that the use of the forced answering (FA) option in online surveys results in reduced data. They especially examined that forcing respondents to answer questions in ... [more ▼]

Relevance: Recent studies have shown that the use of the forced answering (FA) option in online surveys results in reduced data. They especially examined that forcing respondents to answer questions in order to proceed through the questionnaire leads to higher dropout rates and lower answer quality. However, no study researched the psychological mechanism behind the correlation of FA on dropout and data quality before. This response behavior has often been interpreted as psychological reactance reaction. So, the Psychological Reactance Theory (PRT) predicts that reactance appears when an individuals’ freedom is threatened and cannot be directly restored. Reactance describes the motivation to restore this loss of freedom. Respondents could experience FA as a loss of freedom, as (s)he is denied the choice to leave a question unanswered. According to PRT, possible reactions in this situation might be to quit survey participation, to fake answers or to show satisficing tendencies. Research content: This study explores the psychological mechanism that effects response behavior in FA condition (compared to non-FA- condition). Our major hypothesis is that forcing respondents to answer will cause reactance, which turns into increasing dropout rates, decreasing answer quality and a satisficing behavior. Methods and Data: We used an online survey-experiment with two conditions (forced and non-forced answering instructions). The sample consists of 914 participants. Throughout the whole questionnaire, a dropout button was implemented on each page. In both conditions, this button led to the same page that fully compliant participants reached at the end of the questionnaire. Reactance was measured with a self-constructed four-item reactance scale. To determine answer quality, we used self-report for faking as well as the analysis of answers to open ended questions. Results: Zero-order effects showed that FA increased state reactance and questionnaire dropout as well as it reduced answer length in open-ended questions. Mediation analysis (Condition -> state reactance -> dropout/answer quality) supported the hypothesis of reactance as an underlying psychological mechanism behind negative FA effects on data quality. Added Value: This is the first study which offers statistical evidence for the often proposed reactance effect influencing response behavior. This offers a base for a deeper psychological reflection of the use of the FA-option. [less ▲]

Visuo-spatial abilities are key for children’s verbal number skills

Poster (2017, February 22)

Verbal number skills (i.e. counting and number naming) are milestones in numerical development. The aim of the present study was to clarify the role of different verbal abilities (VA) and visuo-spatial ... [more ▼]

Verbal number skills (i.e. counting and number naming) are milestones in numerical development. The aim of the present study was to clarify the role of different verbal abilities (VA) and visuo-spatial abilities (VSA) in the development of these verbal number skills in kindergarten. We recruited 152 children (mean age: 5.8 years) and administered different measures of VA (e.g. phonological awareness, pseudoword recall) and of VSA (e.g. spatial perception, copying) to assess their contribution to verbal number skills. Firstly, we computed two independent regression models, a “VA only” model explaining 23% of variance, and a “VSA only” model explaining 38% of variance. Adding verbal measures to the “VSA only” model does not lead to a significant increase in R2. Our results show that VSA, rather than VA, contribute to a larger extent to children’s verbal number skills. Intriguingly, the development of verbal number skills builds on VA, but more importantly on VSA. These results are potentially informative for the conception early mathematics interventions. [less ▲]

From meta-genomics to causality: Understanding the role of colon cancer-associated bacteria in colorectal cancer

Poster (2017, February 05)

The human gastrointestinal tract is home for trillions of bacteria that influence homeostasis and health in a complex biological system: the gut microbiome. Accumulating evidence suggests that a state of ... [more ▼]

The human gastrointestinal tract is home for trillions of bacteria that influence homeostasis and health in a complex biological system: the gut microbiome. Accumulating evidence suggests that a state of pathological imbalance in the microbiome (dysbiosis) is present in patients suffering from colorectal cancer (CRC). To date, microbiome studies identified specific bacteria being associated with dysbiosis in CRC. Some of these bacteria (e.g. Fusobacteria) directly or indirectly interact with cancer and immune cells of their host. However, current studies only focused on certain microbes in detail, hence, their role in the etiology of the disease remains elusive. Accordingly, my project investigates the role of CRC-associated bacteria in tumor initiation and progression while addressing the question: which and what kind of microbes interact with, favor, or can cause CRC? In a first step, we identified CRC-associated bacteria, enriched at the tumor site of Luxembourgish CRC patients. By using Fusobacterium nucleatum as our study model, we predicted and optimized bacterial growth (media) in silico by using a genome-scale metabolic reconstruction model for a constraint-based modelling approach. Next, we assessed bacterial growth and metabolism in the optimized growth medium by using flow cytometry and mass spectrometry. Finally, we co-cultured the bacteria together with primary patient-derived cultures in the recently developed, microfluidics-based, human-microbial cross-talk model (HuMiX) [1]. As part of our ongoing validations, we infected patient-derived, healthy and cancerous 3D colonic organoids with our bacterial candidate. This workflow enables us to analyze pro-tumorigenic capacities of CRC-associated bacteria on healthy and cancerous colonocytes. It will serve as a promising tool for future analysis of host-microbial interaction mechanisms of various CRC-associated bacteria on a transcriptomic, proteomic, and metabolomic level. [1] Shah P, Fritz JV, Glaab E, Desai MS, Greenhalgh K et al. (2016) A microfluidics-based in vitro model of the gastrointestinal human-microbe interface. Nature communications 7: 11535. [less ▲]

Cats parallel great apes and corvids in motor self-regulation, but size matters

Poster (2017)

We tested domestic cats in the cylinder task, and found that they perform better ifthe cylinder is larger. We also found that their highest performance parallels that ofgreat apes and corvids, which are ... [more ▼]

We tested domestic cats in the cylinder task, and found that they perform better ifthe cylinder is larger. We also found that their highest performance parallels that ofgreat apes and corvids, which are known as the best performing animals on this task.The cylinder task is used to test animals’ motor self-regulation. Recently a large-scalestudy tested 36 species on the task and found that absolute brain size correlatedwith the performance; with great apes as top performers. Another study showedthat corvids perform as good as great apes despite having smaller absolute brainsize. We questioned whether average brained animals have as poor motor self-regulation as suggested, as it appears highly maladaptive; instead the results couldbe a reflection of the sensorimotor set-up of different species in relation to thematerials used. No cats have been tested on the task before.Eight adult domestic cats participated in four versions of the task. We manipulatedthe size and materials, with two large (18.5 cm diameter) and two small (9.5 cmdiameter) cylinders, out of glass and plastic respectively. Each condition comprisedof two phases. First, a subject learned to retrieve a reward from an opaque cylinder(5 trials), and after a 24-hour delay was tested on a transparent cylinder (10 trials). Aretrieval of the reward without touching the cylinder’s front counted as a successfultrial.The success rate differed between conditions, and was highest (98,75) for the “smallplastic” condition. There was a significant main effect of the cylinder size on thesuccess rate [F(1,7)=64.06, p <0.001]. We discuss these results, as they call intoquestion whether the large-scale study took into account the sensorimotor architecture of each species, and more importantly, whether the task alwaysmeasures motor self-regulation. [less ▲]

Comparison of Several RANS Modelling for the Pavia TRIGA Mark II Research Reactor

Poster (2017)

In this study, a detailed analysis of the turbulent regime within the core of the Pavia TRIGA Mark II reactor is perfomed by means of an in-depth comparison of the RAS (Reynolds-Averaged Simulation ... [more ▼]

In this study, a detailed analysis of the turbulent regime within the core of the Pavia TRIGA Mark II reactor is perfomed by means of an in-depth comparison of the RAS (Reynolds-Averaged Simulation) turbulence models implemented in OpenFOAM. Aim of this analysis is to give some important information with respect to the flow regime within the core. The performance of the various models is tested against a LES (Large Eddy Simulation) of the innermost channel. [less ▲]

Towards Estimating Urban Macroscopic Fundamental Diagrams From Mobile Phone Signaling Data: A Simulation Study

Poster (2017)

A study of the molecular mechanisms underlying teh response of human colorectal adenomacarcinoma enterocytes to prebiotics and probiotics

Poster (2017)

Selection criteria of Microthrix parvicella as lipid accumulator in activated sludge treatment plants

Poster (2017)

Langzeitkonsequenzen von frühkindlichem Stress

Poster (2017)

Traumatische Belastungen während der Kindheit können das Risiko für die Entwicklung unsicherer Bindungsstile erhöhen, die bereits mit langfristigen psychischen und körperlichen Gesundheitsproblemen in ... [more ▼]

Traumatische Belastungen während der Kindheit können das Risiko für die Entwicklung unsicherer Bindungsstile erhöhen, die bereits mit langfristigen psychischen und körperlichen Gesundheitsproblemen in Beziehung gebracht wurden. Die zugrundeliegenden Prozesse sind allerdings noch weitestgehend unklar. Wir präsentieren zwei Studien, die den Zusammenhang zwischen kindlichem Stress und Gesundheit im Erwachsenenalter sowie Körperwahrnehmung und Gedächtnisfähigkeit untersuchen. In der ersten Studie nahmen 199 Teilnehmer an einer Onlineumfrage teil, bei der Gesundheit, frühkindliches Trauma, Resilienz und Zurückweisungssensitivität gemessen wurden. Teilnehmer mit geschiedenen Eltern berichteten erhöhte psychische Belastungswerte, kindliches Trauma, Zurückweisungssensitivität und weniger Resilienz. Die Beziehung zwischen elterlicher Scheidung und psychischer Gesundheit konnte vollständig durch diese vier Faktoren erklärt werden (Varianzaufklärung 44%). In einer zweiten Studie wurden bei 60 Teilnehmern verschiedene Selbstbericht-Parameter erhoben und die Gedächtnis- und Interozeptionsfähigkeit vor und nach einem Stresstest untersucht. Erwachsene mit einer Vorgeschichte von elterlicher Trennung berichteten mehr bindungsbezogene Angst und Vermeidung als Kontrollpersonen. Das Erlebnis einer elterlichen Scheidung war negativ mit der Gedächtnisleistung nach dem Stresstest korreliert. Weiterhin weisen die Ergebnisse auf einen quadratischen Zusammenhang zwischen Stress und Interozeptionsfähigkeit hin. [less ▲]

Characterization of Primary and Acute Isolated Microglia under Homeostatic and Inflammatory Conditions

Poster (2017)

Einfluss von akutem Stress auf die Verhaltensinhibition –eine ERP Studie

Poster (2017)

Stress beeinflusst verschiedene Kognitionen, wie zum Bespiel Lernen und Gedächtnisbildung/-abruf. Der Einfluss von Stress auf exekutive Funktionen ist erst in den letzten Jahren vermehrt untersucht worden ... [more ▼]

Stress beeinflusst verschiedene Kognitionen, wie zum Bespiel Lernen und Gedächtnisbildung/-abruf. Der Einfluss von Stress auf exekutive Funktionen ist erst in den letzten Jahren vermehrt untersucht worden. Diese Studien zeigen, dass akuter Stress das Arbeitsgedächtnis, kognitive Flexibilität und kognitive Inhibition negative beeinflusst, während Verhaltensinhibition durch Stress verbessert zu werden scheint. Bislang ist wenig über den Einfluss von Stress auf die zugrundelie- genden kognitiven Prozesse der Verhaltensinhibition bekannt. Um dies zu untersuchen wurden 55 gesunde junge Männer und Frauen zunächst dem sozialevaluativen Kaltwasserstresstest bzw. einer Kontrollbedingung mit warmen Wasser unterzogen und bearbeitet danach eine Go-Nogo-Aufgabe, während EEG und EKG aufgezeichnet wurden. Im Verlauf des Experiments wurden fünf Speichelproben abgegeben. Erste Analysen zeigen, dass akuter Stress die Verhaltensinhibition in Abhängigkeit der Stress-induzierten Cortisol-Konzentration beein- flusst. Versuchspersonen mit einem deutlichen Cortisolanstieg (> 2 nmol/l, Cortisol-high-responder) zeigten eine verbesserte Verhaltens- inhibition, während gestresste Versuchspersonen ohne nennenswer- ten Cortisolanstieg (Cortisol-low-responder) die schlechteste Leistung zeigten. Die Ergebnisse der EKPs bestätigen diesen Eindruck. Wäh- rend die Nogo N2 nur durch den akuten Stress moduliert wurde, zeigte die Nogo P3 Änderungen in Abhängigkeit der Stress- induzierten Cortisol-Konzentration. Diese Ergebnisse bestätigen bisherige Befunde zur verbesserten Verhaltensinhibition durch akuten Stress. Gleichzeitig deuten sie darauf hin, dass die zugrundeliegenden kognitiven Prozesse unter- schiedlich beeinflusst werden und dass Cortisol bei der Umverteilung kognitiver Ressourcen durch Stress entscheidend ist. [less ▲]

On the Impact of Multi-GNSS Solutions on Satellite Products and Positioning

Poster (2016, December 12)

In Global Navigation Satellite System (GNSS) coordinate time series unrecognised errors and un-modelled (periodic) effects may bias non-linear motions induced by geophysical signals. Those spurious ... [more ▼]

In Global Navigation Satellite System (GNSS) coordinate time series unrecognised errors and un-modelled (periodic) effects may bias non-linear motions induced by geophysical signals. Those spurious signals can be caused either due to un-modelled long periodic signals or propagation of sub-daily signals into the time series. Understanding and mitigating these errors is vital to reduce biases and on revealing subtle geophysical signals. Mostly, the spurious signals are caused by unmodelled errors which occur due to the draconitic years, satellite ground repeats and absorption into resonant GNSS orbits. Accordingly, different features can be observed in GNSS-derived products from different single-GNSS or combined-GNSS solutions. To assess the nature of periodic signals on station coordinate time series Precise Point Positioning (PPP) solutions are generated using the Bernese GNSS Software V5.2. The solutions consider only GPS, only GLONASS or combined GPS+GLONASS (GNSS) observations. We assess the periodic signals of station coordinates computed using the combined International GNSS Service (IGS) and four of its Analysis Centers (ACs) products. [less ▲]

Error analysis of Tide Gauge Benchmark Monitoring (TIGA) Analysis Center stacked solutions

Poster (2016, December 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 1995 to the end of 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 Centers (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 center at the University of La Rochelle (www.sonel.org). The TAC solutions contain a total of over 700 stations. This study focuses on the evaluations of any systematic error present in the three TIGA analysis center (TAC) SINEX solutions: the British Isles continuous GNSS Facility – University of Luxembourg consortium (BLT), the GeoForschungsZentrum (GFZ) Potsdam, and of the University of La Rochelle (ULR). We have analyzed the residual position time series of the individual TAC a combination of automatic and manual discontinuity identification, applying a post-seismic deformation model adopted from ITRF2014 for those stations that are affected by earthquakes, followed by the stacking of the daily solution of the individual TAC into a long term linear frame. We have carried out the error analysis using the Combination and Analysis of Terrestrial Reference Frame (CATREF) software package. The TIGA Combination Centre (TCC) at the University of Luxembourg (UL) is responsible for providing a combined solution with a global set of vertical land movement estimates. [less ▲]

Bayesian inference for parameter identification in computational mechanics

Poster (2016, December 12)

Poster: LuST-LTE: A Simulation Package for Pervasive Vehicular Connectivity

Poster (2016, December 08)

Recent technological advances in communication technology have provided new ways to understand human mobility. Connected vehicles with their rising market penetration are particularly representative of ... [more ▼]

Recent technological advances in communication technology have provided new ways to understand human mobility. Connected vehicles with their rising market penetration are particularly representative of this trend. They become increasingly interesting, not only as sensors, but also as participants in Intelligent Transportation System (ITS) applications. More specifically, their pervasive connectivity to cellular networks enables them as passive and active sensing units. In this paper, we introduce LuST-LTE, a package of open-source simulation tools that allows the simulation of vehicular traffic along with pervasive LTE connectivity. [less ▲]

Game-Theoretic Framework for Integrity Verification in Computation Outsourcing

Poster (2016, November 03)

n the cloud computing era, in order to avoid computational burdens, many organizations tend to outsource their computations to third-party cloud servers. In order to protect service quality, the integrity ... [more ▼]

n the cloud computing era, in order to avoid computational burdens, many organizations tend to outsource their computations to third-party cloud servers. In order to protect service quality, the integrity of computation results need to be guaranteed. In this paper, we develop a game theoretic framework which helps the outsourcer to maximize its payo while ensuring the desired level of integrity for the outsourced computation. We de ne two Stackelberg games and analyze the optimal se ing’s sensitivity for the parameters of the model. [less ▲]

Facteurs psychologiques, cognitifs et les influences contextuelles dans la douleur et la souffrance liée à la douleur

Poster (2016, November)

Behavioral Clustering of Non-Stationary IP Flow Record Data

Poster (2016, October)

Different aspects of spatial skills and their relation to early mathematics

Poster (2016, September 29)

We aimed at investigating the predictive role of spatial skills for arithmetic and number line estimation in kindergarten children (N = 125). Several studies highlighted the relation between spatial ... [more ▼]

We aimed at investigating the predictive role of spatial skills for arithmetic and number line estimation in kindergarten children (N = 125). Several studies highlighted the relation between spatial skills and mathematics. However, due to their non-unitary nature, different aspects of spatial skills need to be differentiated to clarify the relative importance of different aspects of spatial skills for mathematics. In the present study, at time 1, a spatial perception task, a spatial visualization task and visuo-motor integration task were administered to assess different aspects of spatial skills. Furthermore we assessed domain-specific skills and verbal domain-general skills. Four months later, the same children performed an arithmetic task and a number line estimation task to evaluate how the abilities measured at time 1 predict early mathematics. Hierarchical regression modelling revealed that children’s performance on the spatial perception task was predictive of their performance in both arithmetic and number line estimation, whereas visuo-motor integration and knowledge of the Arabic numerals significantly predicted arithmetic. The predictive relation between spatial perception and arithmetic was partially mediated by the number line estimation task. Our findings emphasize the role of spatial skills, notably spatial perception, in mathematical development. These results reveal the importance to differentiate within the construct of spatial skills when studying their role in numerical development. The development and implementation of pre-school interventions fostering children’s spatial perception and visuo-motor integration might thus be a promising approach for providing children with a sound foundation for later mathematical learning. [less ▲]

Liquid Transport in Bi-disperse Particle Beds

Poster (2016, September 15)

Flow of highly saturated wet granular matter is encountered in wide range of engineering application, particularly in the pharmaceutics, food industry and energy sector , in addition, granular particles ... [more ▼]

Flow of highly saturated wet granular matter is encountered in wide range of engineering application, particularly in the pharmaceutics, food industry and energy sector , in addition, granular particles beds usually compose of various of particle properties (i.e.,, shape, size, density, etc.) and it well know that particle size polydispersity and shape significantly influence on the transport of mass and liquid in a fluidized bed system. [less ▲]

The role of theatre in education for developing multilingual skills and global competencies

Poster (2016, September 01)

Energy fractionalization after single electron injection into an interacting helical liquid

Poster (2016, September)