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See detailSelf-assembly of binary colloidal nanocrystals
Mravlak, Marko UL

Doctoral thesis (2017)

The synthesis of functional nanoparticles is an important step in the hierarchical construction of hybrid materials for nanotechnological applications. A useful path to build these components is to use ... [more ▼]

The synthesis of functional nanoparticles is an important step in the hierarchical construction of hybrid materials for nanotechnological applications. A useful path to build these components is to use colloidal nanocrystals that can spontaneously agglomerate into ordered structures under confinement. The focus of this thesis is to explore the diversity of superstructures that can be self-assembled using binary dispersions where the dispersed colloids have spherical or quasi-spherical shapes and interact through simple potentials with repulsive cores and short-range attractions. Using computer simulations we demonstrate that agglomeration experiments with heterogeneous binary mixtures of nanoparticles can be exploited for the synthesis of structured clusters which are proposed as potential intermediate building blocks in hierarchical self-assembly of colloidal molecules and crystals. To describe the structural properties of aggregates resulting from confined mixtures of particles with heterogeneous attractions we analyse the structure diagrams of binary Lennard-Jones clusters by means of a basin-hopping global optimisation approach for a broad range of cluster sizes, compositions and interaction energies and present a large database of minimal energy structures. We identify a variety of structures such as core-shell clusters, Janus clusters and clusters in which the minority species is located at the vertices of icosahedra. For a binary mixture with heterogeneous particle diameters we use molecular dynamics simulations to demonstrate that pressure-dependent inter-particle potentials affect the self-assembly route of the confined particles. This is in agreement with experiments where crystalline superlattices, Janus particles, and core-shell particle arrangements form in the same dispersions for moderate changes in the working pressure or the surfactant that sets the Laplace pressure inside the droplets. Comparison of experimental analysis and simulations confirms that the onset of self-assembly depends on particle size and pressure. Finally, we explore regular superlattices into which clusters can arrange by investigating the equilibrium phase behaviour for a monodisperse system of Mackay icosahedra. Monte Carlo simulations show that either a fluid phase, a crystal phase or rotator phases with different degrees of rotational correlations form. We analyse the correlations using the positional and orientational pair correlation functions and find that the densest lattice packing of hard icosahedra is stable at finite temperatures. [less ▲]

Detailed reference viewed: 118 (19 UL)
See detailSelf-Assessment in Elementary School with a Tablet-Computer-Based Tool: A Chance for Fairer Educational Assessment?
Villanyi, Denise UL

Doctoral thesis (2018)

Student self-assessment (SSA) is beneficial for students’ learning and achievement through processes of self-regulation. Furthermore, SSA is a valuable feedback for the teachers on students’ perceptions ... [more ▼]

Student self-assessment (SSA) is beneficial for students’ learning and achievement through processes of self-regulation. Furthermore, SSA is a valuable feedback for the teachers on students’ perceptions of their competencies. SSA can complete teachers’ view on and judgment about the students’ competencies and it can help teachers to adapt teaching and learning activities to better meet the needs of the students. Knowing that teachers’ assessments can be biased regarding students’ ethnic or immigration background, students’ SAs might be an important complementary source of information that increases fairness in educational assessment. Despite its proven benefits, the implementation of self-assessment (SA) in elementary school classrooms is limited, most probably due to the skepticism towards learners’ SA accuracy at all ages, but even more so when students are younger. The objective of the present dissertation was to capture students’ SAs of key academic competencies with an innovative tool—a tablet-computer-based SA-tool—, and to make it visible to teachers by giving them feedback on their students’ SAs. The dissertation is based on three empirical studies. In the first study, we investigated, whether third- and fourth-graders have the ability to assess key academic competencies (mathematics, German reading comprehension) with acceptable accuracy, when provided with an innovative tablet-computer-based tool that was designed respecting the requirements that facilitate SA for that age group. The second study concentrated on the domain of mathematics. We investigated how mathematics self-efficacy, the construct measured with the tool, relates to other competence beliefs such as mathematics self-concept and general academic self-concept and covariates (standardized tests in mathematics, reading comprehension, listening, comprehension; general academic and mathematics interest; general academic and mathematics anxiety; and gender). In the third study, we investigated whether feedbacks on students’ SAs and achievement test results (from Luxembourg school monitoring) are valuable information for teachers that they would triangulate with their own assessments. We hypothesized that the information captured via SSA and achievement test would trigger critical reflection in teachers, and offer them feedback on the appropriateness of their assessments (unbiased versus biased treatment) and thus make educational assessment fairer. The findings of the three studies contribute to answer the questions of how SA can be implemented in the classroom (Grades 3 and 4) in a way that it becomes meaningful to students and teachers, and whether SSA in the classroom is a chance for fairer educational assessment. Based on the results of Studies 1 and 2, we conclude that with an appropriate SA-tool, displaying self-efficacy items on task level on tablet-computer, third- and fourth-graders were able to assess key academic competencies with acceptable accuracy and thus to give valuable information to the teachers. Based on the results of Study 3, we conclude that teachers were able to triangulate the information from students’ SAs with their own assessments and with external achievement test results. Indeed, SSA in the classroom can be a chance for fairer educational assessment. [less ▲]

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See detailSelf-care Assistive Technologies: A systematic review of studies on efficiency and factors influencing their use
Abri, Diana UL; Boll, Thomas UL; Ferring, Dieter UL

Scientific Conference (2017, July 05)

A gradual decline in functional and mental capacity, as well as a growing risk of care dependency constitute major concerns of life in old age. These are expected to become more urgent in the future ... [more ▼]

A gradual decline in functional and mental capacity, as well as a growing risk of care dependency constitute major concerns of life in old age. These are expected to become more urgent in the future, because the old-age dependency ratio in the EU is projected to nearly double until 2060 due to demographic change. On the other side, there is a strong desire to maintain the autonomy of older people as long as possible. In reaction to this, there have been strong health and social policy recommendations across Europe to develop and promote the use of assistive technologies (ATs). Whereas systematic reviews already exist for several kinds of ATs, reviews about self-care ATs are still missing. Based on a systematic literature search in PsycINFO, MEDLINE, and Google Scholar databases 203 papers were identified of which 13 were included according to our selection criteria. The methodological quality of all the reviewed studies is evaluated. We reviewed findings on objective and subjective indicators of independent living as efficiency criteria as well as evidence about facilitating and inhibiting factors in the use of these technologies. Self-care ATs turned out to be efficient, with respect to care hours, independence level, and self-reported satisfaction. The actual use of these ATs was influenced by diverse personal, contextual, and device aspects. Lack of randomized control trial studies and the need for a further research about ATs in the diverse subdomains of self-care activities is revealed. Based on the findings of the current study, we generate recommendations for future research. [less ▲]

Detailed reference viewed: 130 (43 UL)
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See detailSelf-commuting lattice polynomial functions on chains
Couceiro, Miguel UL; Lehtonen, Erkko UL

in Aequationes Mathematicae (2011), 81(3), 263-278

We provide sufficient conditions for a lattice polynomial function to be self-commuting. We explicitly describe self-commuting polynomial functions on chains.

Detailed reference viewed: 70 (0 UL)
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See detailSelf-Concept Clarity Scale (SCSS): Psychometric properties and aggression correlates of a German version
Steffgen, Georges UL; Da Silva, Marco; Recchia, Sophie UL

in Individual Differences Research (2007), 5(4), 230-245

Two studies (participants: N =126; N = 247) examined the reliability and validity of the German version of the Self-Concept Clarity Scale (Stucke, 2002). The results from exploratory and confirmatory ... [more ▼]

Two studies (participants: N =126; N = 247) examined the reliability and validity of the German version of the Self-Concept Clarity Scale (Stucke, 2002). The results from exploratory and confirmatory factor analysis showed a one-factor solution fit best for adults, whereas a two-factor solution fit best for adolescents. Internal reliability was high for adult and adolescent samples. In adults, self-concept clarity was negatively correlated with both narcissism and self-reported aggression. The German version of the SCCS is a useful scale for predicting aggression, especially in adults. [less ▲]

Detailed reference viewed: 337 (3 UL)
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See detailSelf-concept in adolescence: A longitudinal study on reciprocal effects of self-perceptions in academic and social domains
Preckel, Franzis; Niepel, Christoph UL; Schneider, Marian et al

in Journal of Adolescence (2013), 36

Detailed reference viewed: 141 (3 UL)
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See detailSelf-concept, interest, and achievement within and across math and verbal domains in first- and third-graders
van der Westhuizen, Lindie UL; Arens, A. Katrin; Keller, Ulrich UL et al

Scientific Conference (2020, April)

The generalized internal/external frame-of-reference (G)I/E model explains the formation of domain-specific motivational-affective constructs through social and dimensional comparisons. We examined the ... [more ▼]

The generalized internal/external frame-of-reference (G)I/E model explains the formation of domain-specific motivational-affective constructs through social and dimensional comparisons. We examined the associations between verbal and math achievement and corresponding domain-specific academic self-concepts (ASCs) and interests for first-graders and third-graders (N=21,192). Positive achievement-self-concept and achievement-interest relations were found within matching-domains in both grades, while negative cross-domains achievement-self-concept and achievement-interest relations were only found for third-graders. These findings suggest that while the formation of domain-specific ASCs and interests seem to rely on social and dimensional comparisons for third-graders, only social comparisons seem to be in operation for first-graders. Gender and cohort invariance was established in both grade levels. Findings are discussed within the framework of ASC differentiation and dimensional comparison theory. [less ▲]

Detailed reference viewed: 24 (1 UL)
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See detailSelf-confidence and sports performance
Bund, Andreas UL

Scientific Conference (2001, July)

Detailed reference viewed: 51 (1 UL)
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See detailSelf-confidence and sports performance
Bund, Andreas UL

in Mester, J.; King, G.; Strüder, H. (Eds.) et al 6th Annual Conference of the ECSS. Book of Abstracts (2001, July)

Detailed reference viewed: 54 (0 UL)
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See detailSelf-Consistent Quantum Master Equation Approach to Molecular Transport
Esposito, Massimiliano UL; Galperin, Michael

in Journal of Physical Chemistry C (2010), 114(48),

We propose a self-consistent generalized quantum master equation (GQME) to describe electron transport through molecular junctions. In a previous study [Esposito, M.; Galperin, M. Phys. ReV. B 2009, 79 ... [more ▼]

We propose a self-consistent generalized quantum master equation (GQME) to describe electron transport through molecular junctions. In a previous study [Esposito, M.; Galperin, M. Phys. ReV. B 2009, 79, 205303], we derived a time-nonlocal GQME to cure the lack of broadening effects in Redfield theory. To do so, the free evolution used in the Born-Markov approximation to close the Redfield equation was replaced by a standard Redfield evolution. In the present paper, we propose a backward Redfield evolution leading to a time-local GQME which allows for a self-consistent procedure of the GQME generator. This approach is approximate but properly reproduces the nonequilibrium steady-state density matrix and the currents of an exactly solvable model. The approach is less accurate for higher moments such as the noise. [less ▲]

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See detailSelf-control motivationally reconsidered: "Acting" self-controlled is different to "being good" at self-control
Grund, Axel UL; Carstens, Christoph-Alexander

in MOTIVATION AND EMOTION (2019), 43(1), 63-81

Self-control is typically conceptualized as an inherent human skill, focusing on the imperative control of thoughts, feelings, and behavior. In the present research, we scrutinize this understanding by ... [more ▼]

Self-control is typically conceptualized as an inherent human skill, focusing on the imperative control of thoughts, feelings, and behavior. In the present research, we scrutinize this understanding by differentiating between an ability self-concept of self-control strength and experiential acts of self-control. Moreover, by taking a motivational perspective, we analyze how much of a role intrapsychic conflict plays in both conceptions of self-control, and with regard to psychological well-being. In cross-sectional Study 1 (N = 228), we compared a typicality measure of experiential acts of imperative self-control with the widely used Self-Control Scale (Tangney et al. in J Pers 72:271-322, 2004). Findings confirm that "being good" at self-control does not correspond to "acting" self-controlled, and that both measures show opposing relationships to intrapsychic conflict, as well as to well-being. In Study 2 (N = 114), we corroborated these findings by using an experience-sampling approach. Multilevel analyses showed that between-person differences (Level 2) in self-control strength were generally unrelated to experiential acts of self-control in everyday life. By contrast, we found a positive Level 2 effect for acting self-controlled. With regard to momentary affect, both between- and within differences (Level 1) in acting self-controlled served as substantial predictors, in addition to momentary self-determination. Other context-dependent effects (i.e., studying vs. leisure time) further emphasize the need to consider motivational interpretations of self-control (strength). [less ▲]

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See detailSelf-controlled learning of a complex motor skill: Effects of the learner's preferences on performance and self-efficacy.
Bund, Andreas UL; Wiemeyer, Josef

in Journal of Human Movement Studies (2004), 47

Detailed reference viewed: 150 (0 UL)
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See detailSelf-controlled learning of motor skills: Is there a trade-off between cognition and motivation?
Bund, Andreas UL

in Balagué, N.; Torrents, C.; Vilanova, A. (Eds.) et al Book of Abstracts (2013, June)

Detailed reference viewed: 72 (0 UL)
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See detailSelf-controlled learning of the forehand topspin stroke in table tennis
Bund, Andreas UL

in Kahn, Jean-Francois; Lees, Adrian; Maynard, Ian (Eds.) Science and Racket Sports III (2004, February)

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See detailSelf-controlled learning of the forehand topspin stroke in table tennis.
Bund, Andreas UL

Scientific Conference (2003, May)

Detailed reference viewed: 79 (0 UL)
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See detailSelf-controlled practice of decision-making skills
Bund, Andreas UL; Memmert, Daniel

Poster (2006, July)

Detailed reference viewed: 93 (1 UL)
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See detailSelf-controlled practice of decision-making skills
Bund, Andreas UL; Memmert, Daniel

in Hoppeler, H.; Reilly, T.; Tsolakidis, E. (Eds.) et al Book of Abstracts (2006, July)

Detailed reference viewed: 80 (0 UL)
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See detailA self-correcting iteration schema for argumentation networks
Gabbay, Dov M. UL; Rodrigues, Odinaldo

in Computational Models of Argument - Proceedings of COMMA 2014, Atholl Palace Hotel, Scottish Highlands, UK, September 9-12, 2014 (2014)

Detailed reference viewed: 31 (2 UL)