Developing oral language skills in language-minority children

Doctoral thesis (2018)

The aim of the research presented in this thesis is two-fold. Firstly, it explores the early oral language development in Portuguese-speaking language-minority children growing up in Luxembourg in the ... [more ▼]

The aim of the research presented in this thesis is two-fold. Firstly, it explores the early oral language development in Portuguese-speaking language-minority children growing up in Luxembourg in the kindergarten years. Secondly, it purports to develop and evaluate the effectiveness of a 30-week oral language intervention programme designed to support the home language development in language-minority children, using a randomised controlled study design. The study specifically examines the hypothesis that skills acquired in a first language can transfer to a second language. The study adopts a longitudinal experimental design and includes a sample of 186 Portuguese-speaking kindergarten children in Luxembourg. Children were randomly allocated to a Portuguese oral language group (N = 93) or an active control group (N = 93). Participants were followed longitudinally and assessed on four occasions over a period of two years. The study also included two peer comparison groups: one classroom peer group from Luxembourg (N = 75) and one age-matched group of monolingual children from Portugal (N = 44). The first key research question addressed was: What are the early oral language skills in Portuguese and Luxembourgish within this group of bilingual language-minority children, and how do these skills develop during the kindergarten years? Results indicate that when compared to their peers in both languages, these children lagged behind. Despite manifesting language growth in Luxembourgish, the language-minority group continued to score below their classroom peers at the end of kindergarten. Findings further suggest that the home language skills of these children are not only less developed at school entry, but are also growing at a slower rate in contrast to the school language. Overall, results raise the possibility that Portuguese-speaking children in Luxembourg might be at risk of acquiring their second language at the expense of their first language. It is clear that these children are in need of targeted language support, not only in their school language but also their home language. The second major research question addressed was: Can an intervention focusing on language-minority children’s home language effectively support their home language development, and might this have knock on effects on second language learning? Results of the randomised controlled trial demonstrate that the newly developed oral language intervention MOLLY successfully improved children’s home language skills. Additionally, the results showed that supporting children in their home language facilitated second language learning. Effect sizes of important educational significance were found on both primary and secondary outcomes in Portuguese and in Luxembourgish. This thesis clearly reinforces that it is possible to effectively support language-minority children’s home language through rich and regular language support in a school setting, without hindering the development of the school language. Findings suggest that supporting children in their home language can facilitate second language learning. This study takes a step forward towards providing robust evidence on what the appropriate conditions are in supporting language-minority children’s language development. [less ▲]

Developing spaces for technology-mediated inquiry in education

Scientific Conference (2014, August 28)

Interactive communication technologies enter our everyday activities at an impressive pace. The proliferation of mobile computing devices coupled to a ubiquitous connectivity initiates a “historical shift ... [more ▼]

Interactive communication technologies enter our everyday activities at an impressive pace. The proliferation of mobile computing devices coupled to a ubiquitous connectivity initiates a “historical shift to digital” and profoundly changes the ways we organize our daily life, communicate, interact, learn or gather information. Digital media also shape the life contexts of our children, who keep on using interactive tools from game-playing to explicit learning activities. This issue creates a growing need to investigate the potential of mobile computing devices in educational contexts and analyse its impact on pedagogical, organisational and technological challenges, the school communities are dealing with. The present paper is discussing findings from a research project that studies the use of tablet-cloud systems in fundamental schools. Luxembourg’s schools and homes are well equipped with computers and internet access. However, little is known about promising strategies and existing barriers to integrate mobile devices effectively into educational contexts. Our research supplies schools with tablet-cloud systems in order to study the impact on collaborative and student-centred learning activities. The project’s core research foci put attention on processes of a) student-led inquiries and creative productions and b) the empowerment of teachers. Prior research often reveals a reluctance of teachers to use IC technologies in classroom activities. Often, teachers experience a lack of digital literacy skills to support students in using interactive devices in classroom inquiries and hands-on activities. This contribution analyses how ICT-enhanced learning practices challenge existing notions of educational achievement, learning, student engagement and participation among the involved teachers. Our transformative research approach puts specific emphasis on threads and opportunities that members of four fundamental school communities experience concerning technological, organisational and pedagogical innovation. We ground our developmental work on the concept of ‘expansive learning’, where “learners learn something that is not yet there. In other words, the learners construct a new object and concept for their collective activity, and implement this new object and concept in practice“ (Engeström & Sannino 2010, 2). Cultural-historical activity theory (CHAT) offers a sound theoretical and methodological framework for implementing and investigating innovation in organisations and institutions, especially in order to interrelate individual and collective actions. CHAT considers both as dialectically interrelated, that is to say, they can be understood only historically and in interaction with each other. The research data are gathered by a multi-method approach, which combines video-ethnographic data of students’ classroom tasks, multimodal analysis of students’ multimodal productions and self-recordings (on the cloud), video-taped stimulated recall sessions with students about their own learning. Excerpts from these data sets are discussed with teachers in developmental work sessions to identify current barriers and successful strategies to integrate technology in learning and teaching practices. The outcomes of our analysis allow to identify potential levers for increasing the use of mobile computing devices in educational contexts and expand the object of socio-digital activity systems in the field of education. [less ▲]

Developing the AM G-code based thermomechanical finite element platform for the analysis of thermal deformation and stress in metal additive manufacturing process

in Journal of Mechanical Science and Technology (2023)

The 3D printing process known as SLM involves the melting of the metal powder, which results in a melt-pool. When this melt-pool solidifies, the solidified metal undergoes cooling and reheating in the ... [more ▼]

The 3D printing process known as SLM involves the melting of the metal powder, which results in a melt-pool. When this melt-pool solidifies, the solidified metal undergoes cooling and reheating in the presence of air and multiple laser passes for continuous material consolidation. As a result of such thermal cycles, the manufactured part develops permanent thermal deformation and residual stresses. The current work proposes the FEM and AM G-code based numerical strategy to qualitatively analyze the formation of such deformations and stresses at part scale. A multi-physics model was developed by coupling of transient thermal heat equation with non-linear structural solver. To mimic the consolidation of material with laser motion, the finite elements were activated as per the pattern of metal deposition under the influence of AM G-code. A numerical experiment was conducted to virtually manufacture the part with mechanical properties of 15--5PH stainless steel [1]. We found that the thermomechanical FEM model interfaced with the AM G-code translated data helps to evaluate the comparable trends of thermal deformation and residual stress results with already established studies. This demonstrates that with a given set of operational instructions, how the thermal conduction, convection and radiation drive the AM process by thermally loading the deposited material. Furthermore, the AM G-code interfacing facilitated the communication of laser scanning path with numerical FEM solver. We anticipate that such development may enable the manufacturing and simulation engineers to early estimate the possible final deformation of the AM fabricated part. Additionally, the developed strategy may also be the initial step for the physically informed neural networks to optimize the laser scan path for precise manufacturing of the metal parts. [less ▲]

Development across the life span and (Cross-)Cultural Psychology

Presentation (2019, October 21)

Development and Application of an Asymptotic Level Transport Pollution Model for Luxembourg Energy Air Quality Project

Doctoral thesis (2013)

The connections between air pollution and the increase of respiratory diseases, are well known. In Europe, many efforts have been carried out towards the mitigation of the pollutants’ emissions over the ... [more ▼]

The connections between air pollution and the increase of respiratory diseases, are well known. In Europe, many efforts have been carried out towards the mitigation of the pollutants’ emissions over the last decades. The European Union supports the implementation of structural planning measures to control air pollution. The assessment and evaluation of these air quality policies must be carried out with the help of dedicated integrated assessment models. The use of integrated assessment models, which combine models from different fields, raises the need for developing specific modelling concepts in order to provide results to support policy decisions within a practical time frame. This work presents the methodology and the development of a dedicated air quality model for an integrated assessment model. This approach has been designed for the Luxembourg Energy and Air Quality, LEAQ, integrated assessment model. It combines an air quality model, AUSTAL2000-AYLTP, with a techno-economic model, ETEM, which computes ozone precursors emissions related to energy consumption. The models are coupled via an optimization engine, which minimizes the total energy cost for a given ozone level. AUSTAL2000, a Lagrangian transport model, has been adapted to receive a photochemical module, the AsYmptotic Level Transport Pollution, AYLTP. This module consists of a Look-Up Table of quasi-linear reaction rates. A balance has been found that gives an acceptable level of accuracy, given the reduction of computational time. The results of the air quality model have been compared with measurements, and with the regional model LOTOS-EUROS and are considered satisfactory for this type of approach. Regarding the LEAQ framework, two study cases have been simulated, one including only the national emissions from Luxembourg country, and a second one for the Luxembourg region, including the neighbouring countries emissions. [less ▲]

Development and Application of Liquid Chromatographic Retention Time Indices in HRMS-Based Suspect and Nontarget Screening

in Analytical Chemistry (2021), 93(33), 11601--11611

There is an increasing need for comparable and harmonized retention times (tR) in liquid chromatography (LC) among different laboratories, to provide supplementary evidence for the identity of compounds ... [more ▼]

There is an increasing need for comparable and harmonized retention times (tR) in liquid chromatography (LC) among different laboratories, to provide supplementary evidence for the identity of compounds in high-resolution mass spectrometry (HRMS)-based suspect and nontarget screening investigations. In this study, a rigorously tested, flexible, and less system-dependent unified retention time index (RTI) approach for LC is presented, based on the calibration of the elution pattern. Two sets of 18 calibrants were selected for each of ESI+ and ESI-based on the maximum overlap with the retention times and chemical similarity indices from a total set of 2123 compounds. The resulting calibration set, with RTI set to range between 1 and 1000, was proposed as the most appropriate RTI system after rigorous evaluation, coordinated by the NORMAN network. The validation of the proposed RTI system was done externally on different instrumentation and LC conditions. The RTI can also be used to check the reproducibility and quality of LC conditions. Two quantitative structure−retention relationship (QSRR)-based models were built based on the developed RTI systems, which assist in the removal of false-positive annotations. The applicability domains of the QSRR models allowed completing the identification process with higher confidence for substances within the domain, while indicating those substances for which results should be treated with caution. The proposed RTI system was used to improve confidence in suspect and nontarget screening and increase the comparability between laboratories as demonstrated for two examples. All RTI-related calculations can be performed online at http://rti.chem.uoa.gr/. [less ▲]

Development and characterization of a novel fluorescent indicator protein PMCA4-GCaMP2 in cardiomyocytes.

in Journal of molecular and cellular cardiology (2013), 63

Isoform 4 of the plasma membrane calcium/calmodulin dependent ATPase (PMCA4) has recently emerged as an important regulator of several key pathophysiological processes in the heart, such as contractility ... [more ▼]

Isoform 4 of the plasma membrane calcium/calmodulin dependent ATPase (PMCA4) has recently emerged as an important regulator of several key pathophysiological processes in the heart, such as contractility and hypertrophy. However, direct monitoring of PMCA4 activity and assessment of calcium dynamics in its vicinity in cardiomyocytes are difficult due to the lack of molecular tools. In this study, we developed novel calcium fluorescent indicators by fusing the GCaMP2 calcium sensor to the N-terminus of PMCA4 to generate the PMCA4-GCaMP2 fusion molecule. We also identified a novel specific inhibitor of PMCA4, which might be useful for studying the role of this molecule in cardiomyocytes and other cell types. Using an adenoviral system we successfully expressed PMCA4-GCaMP2 in both neonatal and adult rat cardiomyocytes. This fusion molecule was correctly targeted to the plasma membrane and co-localised with caveolin-3. It could monitor signal oscillations in electrically stimulated cardiomyocytes. The PMCA4-GCaMP2 generated a higher signal amplitude and faster signal decay rate compared to a mutant inactive PMCA4(mut)GCaMP2 fusion protein, in electrically stimulated neonatal and adult rat cardiomyocytes. A small molecule library screen enabled us to identify a novel selective inhibitor for PMCA4, which we found to reduce signal amplitude of PMCA4-GCaMP2 and prolong the time of signal decay (Tau) to a level comparable with the signal generated by PMCA4(mut)GCaMP2. In addition, PMCA4-GCaMP2 but not the mutant form produced an enhanced signal in response to beta-adrenergic stimulation. Together, the PMCA4-GCaMP2 and PMCA4(mut)GCaMP2 demonstrate calcium dynamics in the vicinity of the pump under active or inactive conditions, respectively. In summary, the PMCA4-GCaMP2 together with the novel specific inhibitor provides new means with which to monitor calcium dynamics in the vicinity of a calcium transporter in cardiomyocytes and may become a useful tool to further study the biological functions of PMCA4. In addition, similar approaches could be useful for studying the activity of other calcium transporters during excitation-contraction coupling in the heart. [less ▲]

Development and evaluation of a harmonized whole body physiologically based pharmacokinetic (PBPK) model for flutamide in rats and its extrapolation to humans.

in Environmental research (2020), 182

By their definition, inadvertent exposure to endocrine disrupting compounds (EDCs) intervenes with the endocrine signalling system, even at low dose. On the one hand, some EDCs are used as important ... [more ▼]

By their definition, inadvertent exposure to endocrine disrupting compounds (EDCs) intervenes with the endocrine signalling system, even at low dose. On the one hand, some EDCs are used as important pharmaceutical drugs that one would not want to dismiss. On the other hand, these pharmaceutical drugs are having off-target effects and increasingly significant exposure to the general population with unwanted health implications. Flutamide, one of the top pharmaceutical products marketed all over the world for the treatment of prostate cancer, is also a pollutant. Its therapeutic action mainly depends on targeting the androgen receptors and inhibiting the androgen action that is essential for growth and survival of prostate tissue. Currently flutamide is of concern with respect to its categorization as an endocrine disruptor. In this work we have developed a physiologically based pharmacokinetic (PBPK) model of flutamide that could serve as a standard tool for its human risk assessment. First we built the model for rat (where many parameters have been measured). The rat PBPK model was extrapolated to human where the re-parameterization involved human-specific physiology, metabolic kinetics derived from in-vitro studies, and the partition coefficient same as the rat model. We have harmonized the model by integrating different sets of in-vitro, in-vivo and physiological data into a PBPK model. Then the model was used to simulate different exposure scenarios and the results were compared against the observed data. Both uncertainty and sensitivity analysis was done. Since this new whole-body PBPK model can predict flutamide concentrations not only in plasma but also in various organs, the model may have clinical applications in efficacy and safety assessment of flutamide. The model can also be used for reverse dosimetry in the context of interpreting the available biomonitoring data to estimate the degree to which the population is currently being exposed, and a tool for the pharmaceutical companies to validate the estimated Permitted Daily Exposure (PDE) for flutamide. [less ▲]

Development and Investigation of a New Dry-Stacked Wall System

Doctoral thesis (2015)

The present study examines the potential use of a new mortarless and modular masonry system by carrying out its development and performing experimental, numerical, analytical and practical investigations ... [more ▼]

The present study examines the potential use of a new mortarless and modular masonry system by carrying out its development and performing experimental, numerical, analytical and practical investigations. Different forms of interlocking masonry elements have been modelled and optimised. Fullscale masonry walls were assembled and tested under compressive, flexural and shear loads. The overall structural behaviour was compared to conventional masonry systems such as hollow and shuttering blocks. The investigations showed overall high structural performances for the developed dry-stacked elements. The effect of the dry joint interfaces were extensively investigated experimentally and numerically under FE analysis. Furthermore, a new numerical technique for the determination of stress-percolation in drystacked load-bearing structures has been developed under numerical computing environment, which supports the better understanding of early fissuring in dry-stacked masonry structures. Finally, based on the experimental observations, a numeric-analytical failure mechanism of the dry-stacked masonry structure is proposed under axial and flexural loading. The completion of the package of dry-stacked units, consisting of interlocking modular masonries and an accompanying array of various other precast parts, confirmed the practical issues and solutions towards the exploitation of the developed dry-stacked elements for the construction of ready-to-build, modular and load-bearing walls. [less ▲]

The development and validation of a short conscientiousness questionnaire for large-scale educational assessment

Scientific Conference (2020, July)

Conscientiousness and its subfacets are related to multiple learning-related outcomes. MacCann, Duckworth and Roberts (2009) developed a questionnaire measuring seven subfacets of conscientiousness with ... [more ▼]

Conscientiousness and its subfacets are related to multiple learning-related outcomes. MacCann, Duckworth and Roberts (2009) developed a questionnaire measuring seven subfacets of conscientiousness with 59 items. However, the resources required to complete such long scales often renders it unsuitable for large-scale educational assessment. Consequently, an economic and psychometrically sound conscientiousness questionnaire that is specifically customized for this context is needed. We developed and validated a short version of the MacCann et al. (2009) questionnaire. In study 1, French and German adaptations of the questionnaire were administered to a representative dataset comprising all ninth-graders in Luxembourg (N1=6325, Cohort 2017). Using an exhaustive search algorithm, we identified the optimal combination of four items for each subfacet by simultaneously considering three criteria: goodness of fit, factor saturation, and scalar measurement invariance across the German and French versions. In study 2, we validated our short 28-item questionnaire on a second, independent sample comprising 6,279 Luxembourgish ninth-graders (Cohort 2018). A 7-factor model assuming separate factors for each subfacet obtained acceptable fit (CFI=.93, RMSEA=.04, SRMR=.06). The criterion validity for each subfacet was tested by examining the relation to standardized achievement tests (SATs). In study 3, drawing on a dataset of 275 tenth-graders (linked longitudinally with the ninth-grade data from study 1), evidence of predictive validity (i.e., school grades) was examined. The subfacets of industriousness, caution and perfectionism showed the strongest relations with both SATs (study 2) and school grades (study 3). Our study delivered a short, valid and reliable questionnaire for the assessment of seven conscientiousness facets in the educational context. The scale is invariant across the German and French language versions and its brevity makes it suitable for large-scale educational assessment. [less ▲]