Lehr-Lernprozesse im Physikunterricht - eine Videostudie

[Der Beitrag berichtet aus einem Projekt des DFG-Schwerpunktprogramms Bildungsqualität]. Hintergrund für dieses Projekt sind ... die Befunde aus internationalen Vergleichsstudien (TIMSS, PISA). Die Studie untersucht den deutschen Physikunterricht und die Lernprozesse, die in diesem Unterricht ermöglicht werden. Ziel ist es, eine erste Bestandsaufnahme der "didaktischen Orchestrierung" von Physikuntericht vorzunehmen und insbesondere die Möglichkeiten für verständnisvolles Lernen zu untersuchen ... . Mit theoriegeleiteten Analysen von Unterrichtsbeobachtungen und von ergänzenden Daten aus Befragungen und Tests soll geklärt werden, wie sich Bedingungen bzw. Muster des Physikunterrichts auf Lernprozesse und Bildungsergebnisse auswirken. Der Beitrag konzentriert sich auf die Zielorientierung und die Lernbegleitung. (DIPF/Orig.

Profound Re-Organization of Cell Surface Proteome in Equine Retinal Pigment Epithelial Cells in Response to In Vitro Culturing

The purpose of this study was to characterize the cell surface proteome of native compared to cultured equine retinal pigment epithelium (RPE) cells. The RPE plays an essential role in visual function and represents the outer blood-retinal barrier. We are investigating immunopathomechanisms of equine recurrent uveitis, an autoimmune inflammatory disease in horses leading to breakdown of the outer blood-retinal barrier and influx of autoreactive T-cells into affected horses' vitrei. Cell surface proteins of native and cultured RPE cells from eye-healthy horses were captured by biotinylation, analyzed by high resolution mass spectrometry coupled to liquid chromatography (LC MS/MS), and the most interesting candidates were validated by PCR, immunoblotting and immunocytochemistry. A total of 112 proteins were identified, of which 84% were cell surface membrane proteins. Twenty-three of these proteins were concurrently expressed by both cell states, 28 proteins exclusively by native RPE cells. Among the latter were two RPE markers with highly specialized RPE functions: cellular retinaldehyde-binding protein (CRALBP) and retinal pigment epithelium-specific protein 65kDa (RPE65). Furthermore, 61 proteins were only expressed by cultured RPE cells and absent in native cells. As we believe that initiating events, leading to the breakdown of the outer blood-retinal barrier, take place at the cell surface of RPE cells as a particularly exposed barrier structure, this differential characterization of cell surface proteomes of native and cultured equine RPE cells is a prerequisite for future studies

Assessment of socio-economic functions of tropical lowland transformation systems in Indonesia - sampling framework and methodological approach

EFForTS is a collaborative research center (CRC) which focuses on Ecological and socioeconomic Functions of Tropical Lowland Rainforest Transformation Systems in Sumatra,Indonesia. The paper presents the common sampling frame of the socio economic sub-projects.The investigations and data collections intertwine and complement one another. Thus themethodological approach reflects the idea of an interdisciplinary and integrative research approach. Lead by hypotheses we structured our sampling procedure hierarchically. Starting at the household level in the core villages of the research regions we investigate additional local villages. Further we extend the data collections on the regional level with household, village and trader surveys. The national and international levels we reach by stakeholder interviews with governmental and non-governmental experts. The applied methods are composed of qualitative and quantitative empirical studies

Tailoring of the electrical and thermal properties using ultra-short period non-symmetric superlattices

Thermoelectric modules based on half-Heusler compounds offer a cheap and clean way to create eco-friendly electrical energy from waste heat. Here we study the impact of the period composition on the electrical and thermal properties in non-symmetric superlattices, where the ratio of components varies according to (TiNiSn)ₙ:(HfNiSn)₆₋ₙ, and 0 ⩽ n ⩽ 6 unit cells. The thermal conductivity (κ) showed a strong dependence on the material content achieving a minimum value for n = 3, whereas the highest value of the figure of merit ZT was achieved for n = 4. The measured κ can be well modeled using non-symmetric strain relaxation applied to the model of the series of thermal resistances

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Thermal conductance in spin caloritronics

Spin caloritronics is a field of research that relates the interaction of the electronic spin to a heat flow in a sample. Since the magnitude of such a heat flow is only quantifiable with precise knowledge of the thermal conductivity of the sample, this thesis studies the role of the thermal conductivity in spin caloritronics. However, the 3 omega method as developed by Cahill et al. that isrncommonly used to determine the thermal conductivity in thin films is only capable of analyzing films with a thermal conductivity much lower than that of the substrate.rnThis thesis describes and applies a suitable extension of the original 3 omega method that eliminates these shortcomings. So far, determining the thermal conductivity by this extension led to large numerical uncertainties. The novel data evaluation scheme presented here is based on Bayesian statistics in order to reduce the numerical instability.rnWhile the majority of the projects within spin caloritronics considers the impact of a temperature gradient applied to a solid on the spin structure, this project analyzes the inverse question: How does a change in magnetic texture change the thermal conductivity of a material? In particular, such an effect of a magnetic field on the thermal conductivity was studied concerning thermal transport perpendicular to the film plane in La0.67Ca0.33MnO3 and in the film plane in Permalloy. In both cases the measured change in thermal conductivity inrnthe presence of a magnetic field is discussed.rnFinally, as explained, the community of spin caloritronics relies on accurate values of the thin film thermal conductivity of a number of characteristic materials. Especially Y3Fe5O12 (YIG) is studied frequently, so that as an example of particular interest the thin film thermal conductance of YIG is presented and analyzed. The methods and results presented here provide a different approach to spin caloritronic research and allow a novel path to studying thermal conductivity.Spin-Kaloritronik ist ein Forschungsfeld, in dem die Wechselwirkung von Spin mit Wärmeströmen untersucht wird. Da die Größe solcher Ströme nur durch genaue Kenntnis der Wärmeleitfähigkeit des Materials zu untersuchen ist, beschäftigt sich diese Arbeit mit der Rolle der Wärmeleitfähigkeit im Bereich der Spin-Kaloritronik. Allerdings ist die 3-omega-Methode, wie sie von Cahill et al. etwickelt wurde, und die häufig verwendet wird um die Wärmeleitfähigkeitrndünner Filme zu bestimmen, nicht für alle erdenklichen Film-Substrat-Systeme geeignet.rnDie vorliegende Arbeit beschreibt eine geeignete Erweiterung der ursprünglichen 3-omega-Methode, die diese Mängel ausgleicht, und ihre Anwendung. Bisher war die Bestimmung der Wärmeleitfähigkeit durch diese Erweiterung mit großen numerischen Unsicherheiten verbunden. Das neuartige Auswertungsschema, das hier gezeigt wird, basiert auf Bayesscher Statistik, um diese Unsicherheiten zu reduzieren.rnWährend sich die Mehrzahl der Projekte in der Spin-Kaloritronik mit dem Einfluss eines Temperaturgradienten auf die Spinstruktur eines Festkörpers auseinandersetzt, analysiert diese Arbeit die inverse Fragestellung: Wie beeinflusst eine Änderung der magnetischen Struktur die Wärmeleitfähigkeit eines Materials? Insbesondere wurde ein solcher Effekt eines Magnetfeldsrnauf die Wärmeleitfähigkeit senkrecht zur Filmebene von La0.67Ca0.33MnO3 und in der Filmebene von Permalloy untersucht. In beiden Fällen wird die gemessenernÄnderung der Wärmeleitfähigkeit in einem Magnetfeld diskutiert.rnSchließlich beruht die Spin-Kaloritronik auf präzisen Werten der Dünnfilmwärmeleitfähigkeit relevanter Materialien. Insbesondere wird Y3Fe5O12 (YIG) häufig untersucht, sodass als Beispiel von besonderem Interesse die Dünnfilmwärmeleitfähigkeit von YIG gezeigt und analysiert wird.Die vorgestellten Methoden und Ergebnisse stellen einen anderen Blick auf die Spin-Kaloritronik und einen neuartigen Zugang zur Untersuchung der Wärmeleitfähigkeit dar

Learning Sustainability Entrepreneurship by Doing: Providing a Lecturer-Oriented Service Learning Framework

Due to its growing practical relevance, sustainability entrepreneurship receives a high degree of academic attention. However, literature on how to educate sustainability entrepreneurs remains scarce. A promising didactical approach in this context is service learning. We ask if service learning is an effective way to educate sustainability entrepreneurs, and which framework conditions impact those educators. First, we draw on an established sustainable entrepreneurship capability framework and provide direct evidence from entrepreneurship educators about the effectiveness of service learning. Second, based on grounded theory, qualitative interviews with those educators reveal a framework composed of personal and institutional factors that they have to navigate when provide service learning. Our findings contribute to the interface of service learning and sustainability entrepreneurship by highlighting its effectiveness and the framework conditions for educators