Thoughts on quantifying overconfidence in economic experiments

This article illustrates the difficulties of quantifying overconfidence in economic experiments and suggests a procedure for the development of the reliable overconfidence measurement instrument (test). Following the suggested two-stage procedure a sample measure of overconfidence is developed. First a pilot test is conducted to divide the initial fifty items into three difficulty levels: hard, moderate and easy questions. A final test was compiled of six questions of each difficulty levels. In the second phase a replicability check was run with the final instrument

Thoughts on quantifying overconfidence in economic experiments

This article illustrates the difficulties of quantifying overconfidence in economic experiments and suggests a procedure for the development of the reliable overconfidence measurement instrument (test). Following the suggested two-stage procedure a sample measure of overconfidence is developed. First a pilot test is conducted to divide the initial fifty items into three difficulty levels: hard, moderate and easy questions. A final test was compiled of six questions of each difficulty levels. In the second phase a replicability check was run with the final instrument

Towards engineering the perfect defect in high-performing permanent magnets

Permanent magnets draw their properties from a complex interplay, across multiple length scales, of the composition and distribution of their constituting phases, that act as building blocks, each with their associated intrinsic properties. Gaining a fundamental understanding of these interactions is hence key to decipher the origins of their magnetic performance and facilitate the engineering of better-performing magnets, through unlocking the design of the "perfect defects" for ultimate pinning of magnetic domains. Here, we deployed advanced multiscale microscopy and microanalysis on a bulk Sm2(CoFeCuZr)17 pinning-type high-performance magnet with outstanding thermal and chemical stability. Making use of regions with different chemical compositions, we showcase how both a change in the composition and distribution of copper, along with the atomic arrangements enforce the pinning of magnetic domains, as imaged by nanoscale magnetic induction mapping. Micromagnetic simulations bridge the scales to provide an understanding of how these peculiarities of micro- and nanostructure change the hard magnetic behaviour of Sm2(CoFeCuZr)17 magnets. Unveiling the origins of the reduced coercivity allows us to propose an atomic-scale defect and chemistry manipulation strategy to define ways toward future hard magnets

Reducing extrinsic hysteresis in first-order La(Fe,Co,Si)13 magnetocaloric systems

Reducing extrinsic hysteresis in first-order la (Fe,Co,Si)13 magnetocaloric system

Generation of a Homozygous Transgenic Rat Strain Stably Expressing a Calcium Sensor Protein for Direct Examination of Calcium Signaling

In drug discovery, prediction of selectivity and toxicity require the evaluation of cellular calcium homeostasis. The rat is a preferred laboratory animal for pharmacology and toxicology studies, while currently no calcium indicator protein expressing rat model is available. We established a transgenic rat strain stably expressing the GCaMP2 fluorescent calcium sensor by a transposon-based methodology. Zygotes were co-injected with mRNA of transposase and a CAG- GCaMP2 expressing construct, and animals with one transgene copy were pre-selected by measuring fluorescence in blood cells. A homozygous rat strain was generated with high sensor protein expression in the heart, kidney, liver, and blood cells. No pathological alterations were found in these animals, and fluorescence measurements in cardiac tissue slices and primary cultures demonstrated the applicability of this system for studying calcium signaling. We show here that the GCaMP2 expressing rat cardiomyocytes allow the prediction of cardiotoxic drug side-effects, and provide evidence for the role of Na+/Ca2+ exchanger and its beneficial pharmacological modulation in cardiac reperfusion. Our data indicate that drug-induced alterations and pathological processes can be followed by using this rat model, suggesting that transgenic rats expressing a calcium-sensitive protein provide a valuable system for pharmacological and toxicological studies

Temperature-dependent Dy diffusion processes in Nd-Fe-B permanent magnets

Nd-Fe-B permanent magnets have been coated with 0.6 wt.% dysprosium and annealed at various temperatures to study the impact of the temperature-dependent Dy diffusion processes on both the magnetic properties and the microstructure. When optimum annealing conditions are applied the Dy processed magnets with initial coercivity of similar to 1100 kA m(-1) yield coercivity increases which can exceed 400 kA m(-1) without a significant reduction of the remanent magnetic polarization. The improved stability against opposing magnetic fields can be observed up to a depth of similar to 3 mm along the diffusion direction, restricting the application of the Dy diffusion process to either thin magnets or magnets with tailored coercivity gradients. While in the proximity of the Dy-coated surface, each grain has a Dy-enriched shell with a Dy content of similar to 6 at.%; the Dy concentration decreases exponentially to similar to 1.8 at.% after a diffusion depth of 400 mu m and to similar to 1 at.% after a diffusion depth of 1500 mu m, as was found with wavelength dispersive X-ray spectroscopy and scanning transmission electron microscopy-energy dispersive X-ray spectroscopy, respectively. In the vicinity of the Dy-coated surface, the mechanism of the Dy-shell formation is attributed to the melting/solidification of a heavy-rare-earth-rich intermediate phase during high-temperature annealing. This is based on the observation that a constant Dy concentration over the width of the shells was found. Also an epitaxial relation between the Dy-poor core and the Dy-rich shell was observed by electron backscattered diffraction, which is supported by results obtained with Kerr microscopy

Exploring La(Fe,Si)13-based magnetic refrigerants towards application

Advanced magnetic refrigerants such as La(Fe,Si)13 materials require large entropy and adiabatic temperature changes based on the control of phase change physics and hysteresis. In order to advance their incorporation in prototypes and industrial applications, processing of single phase materials with graded working temperatures needs to be up-scaled and important engineering properties such as the thermal transport properties, corrosion protection and mechanical stability need to be optimized. These issues, including a last step of near net-shaped manufacturing of complex geometries, are discussed in this Viewpoint paper