Identifying Productive Resources in Secondary School Students\u27 Discourse About Energy

A growing program of research in science education acknowledges the beginnings of disciplinary reasoning in students’ ideas and seeks to inform instruction that responds productively to these disciplinary progenitors in the moment to foster their development into sophisticated scientific practice. This dissertation examines secondary school students’ ideas about energy for progenitors of disciplinary knowledge and practice. Previously, researchers argued that students’ ideas about energy were constrained by stable and coherent conceptual structures that conflicted with an assumed unified scientific conception and therefore needed to be replaced. These researchers did not attend to the productive elements in students’ ideas about energy. To analyze the disciplinary substance in students’ ideas, a theoretical perspective was developed that extends Hammer and colleagues’ resources framework. This elaboration allows for the identification of disciplinary productive resources—i.e., appropriately activated declarative and procedural pieces of knowledge—in individual students’ utterances as well as in the interactions of multiple learners engaged in group learning activities. Using this framework, original interview transcripts from one of the most influential studies of students’ ideas about energy (Watts, 1983. Some alternative views of energy. Physics Education, 18/5, 213-217) were analyzed. Disciplinary productive resources regarding the ontology of energy, indicators for energy, and mechanistic reasoning about energy were found to be activated by interviewed students. These valuable aspects were not recognized by the original author. An interpretive analysis of video recorded student-centered discourse in rural Maine middle schools was carried out to find cases of resource activation in classroom discussions. Several cases of disciplinary productive resources regarding the nature of energy and its forms as well as the construction of a mechanistic energy story were identified and richly described. Like energy, resources are manifested in various ways. The results of this study imply the necessity of appropriate disciplinary training for teachers that enables them to recognize and productively respond to disciplinary progenitors of the energy concept in students’ ideas

XDJ1, a gene encoding a novel non-essential DnaJ homologue from Saccharomyces cerevisiae

The gene encoding a novel DnaJ-like protein, termed Xdj1, has been identified by amplification of Saccharomyces cerevisiae genomic DNA. An open reading frame of 1380 bp was detected. Disruption of XDJ1 did not yield any detectable new phenotype. A double-deletion strain containing a disruption of both XDJ1 and YDJ1, another gene coding for a DnaJ-like protein, was still viable. Under a variety of growth conditions, no XDJ1 transcripts could be detected by Northern blot analysis and no translation product was found by immunoblotting with antibody against Xdj1 produced in Escherichia coli. Thus, XDJ1 is either expressed only under very specific conditions or represents a silent gene

Designing Cooperative Gamification: Conceptualization and Prototypical Implementation

Organizations deploy gamification in CSCW systems to enhance motivation and behavioral outcomes of users. However, gamification approaches often cause competition between users, which might be inappropriate for working environments that seek cooperation. Drawing on the social interdependence theory, this paper provides a classification for gamification features and insights about the design of cooperative gamification. Using the example of an innovation community of a German engineering company, we present the design of a cooperative gamification approach and results from a first experimental evaluation. The findings indicate that the developed gamification approach has positive effects on perceived enjoyment and the intention towards knowledge sharing in the considered innovation community. Besides our conceptual contribution , our findings suggest that cooperative gamification may be beneficial for cooperative working environments and represents a promising field for future research

Anomalous magneto-transport in disordered structures: classical edge-state percolation

By event-driven molecular dynamics simulations we investigate magneto-transport in a two-dimensional model with randomly distributed scatterers close to the field-induced localization transition. This transition is generated by percolating skipping orbits along the edges of obstacle clusters. The dynamic exponents differ significantly from those of the conventional transport problem on percolating systems, thus establishing a new dynamic universality class. This difference is tentatively attributed to a weak-link scenario, which emerges naturally due to barely overlapping edge trajectories. We make predictions for the frequency-dependent conductivity and discuss implications for active colloidal circle swimmers in a heterogeneous environment.Comment: accepted for publication in Phys. Rev. Let

Success Factors of Communities for User Driven Content: the Case of Ciao.com

Virtual communities that produce “user driven content ” are a relatively new phenomenon. In this study we present the findings of an exploratory empirical study that focus on the success factors that stimulate content production from the perspective of community members. One main finding is that methods or tools that advance the transparency of what is going on in the community platform results in more content production. This accents the importance of new tools like RSS for example. Furthermore an ambiguous role of sociological motives was found. On the one hand there is statistical evidence that sociological motives and content production activities are closely linked. But on the other hand our descriptive data indicates only very weak sociological forces at work. We discuss some causes that may explain this result. KEYWORDS: Virtual communities, user driven content, exploratory empirical stud

Association of Gene Variants for Mechanical and Metabolic Muscle Quality with Cardiorespiratory and Muscular Variables Related to Performance in Skiing Athletes

BACKGROUND Skiing is a popular outdoor sport posing different requirements on musculoskeletal and cardiorespiratory function to excel in competition. The extent to which genotypic features contribute to the development of performance with years of ski-specific training remains to be elucidated. We therefore tested whether prominent polymorphisms in genes for angiotensin converting enzyme (ACE-I/D, rs1799752), tenascin-C (TNC, rs2104772), actinin-3 (ACTN3, rs1815739) and PTK2 (rs7460 and rs7843014) are associated with the differentiation of cellular hallmarks of muscle metabolism and contraction in high level skiers. MATERIAL & METHODS Forty-three skiers of a world-leading national ski team performed exhaustive cardiopulmonary exercise testing as well as isokinetic strength testing for single contractions, whereby 230 cardiopulmonary measurements were performed in the period from 2015-2018. A total of 168 and 62 data measurements were from the Alpine and Nordic skiing squads, respectively. Ninety-five and one hundred thirty-five measurements, respectively, were from male and female athletes. The average (±SD) age was 21.5 ± 3.0 years, height 174.0 ± 8.7 cm, and weight 71.0 ± 10.9 kg for the analysed skiers. Furthermore, all skiers were analysed concerning their genotype ACE-I/D, Tenascin C, ACTN3, PTK2. RESULTS The genotype distribution deviated from Hardy-Weinberg equilibrium for the ACTN3 genotype, where rs1815739-TT genotypes (corresponding to the nonsense mutation) were overrepresented in world-class skiers, indicating a slow muscle fibre phenotype. Furthermore, the heterozygous rs2104772-AT genotypes of TNC also demonstrated the best scaled peak power output values during ramp exercise to exhaustion. The highest values under maximum performance for heart rate were associated with the rs1799752-II and rs1815739-CC genotypes. The lowest values for peak power of single contractions were achieved for rs1815739-CC, rs1799752-II and rs7843014-CT genotypes. The skiing discipline demonstrated a main influence on cardiorespiratory parameters but did not further interact with genotype-associated variability in performance. DISCUSSION Classically, it is pointed out that muscles of, for example, alpine skiers do not possess a distinct fibre type composition, but that skiers tend to have a preponderance of slow-twitch fibres. Consequently, our findings of an overrepresentation of ACTN3-TT genotypes in a highly selective sample of elite world class skiers support the potential superiority of a slow fibre type distribution. CONCLUSIONS We suggest that one competitive advantage that results from a slow, typically fatigue-resistant fibre type distribution might be that performance during intense training days is better preserved, whereby simply a higher technical training volume can be performed, yielding to a competitive advantage