Electronic structure of fully epitaxial Co2TiSn thin films

In this article we report on the properties of thin films of the full Heusler compound Co2TiSn prepared by DC magnetron co-sputtering. Fully epitaxial, stoichiometric films were obtained by deposition on MgO (001) substrates at substrate temperatures above 600{\deg}C. The films are well ordered in the L21 structure, and the Curie temperature exceeds slightly the bulk value. They show a significant, isotropic magnetoresistance and the resistivity becomes strongly anomalous in the paramagnetic state. The films are weakly ferrimagnetic, with nearly 1 \mu_B on the Co atoms, and a small antiparallel Ti moment, in agreement with theoretical expectations. From comparison of x-ray absorption spectra on the Co L3/L2 edges, including circular and linear magnetic dichroism, with ab initio calculations of the x-ray absorption and circular dichroism spectra we infer that the electronic structure of Co2TiSn has essentially non-localized character. Spectral features that have not been explained in detail before, are explained here in terms of the final state band structure.Comment: 11 pages, 8 figure

Beyond immune escape:a variant surface glycoprotein causes suramin resistance in Trypanosoma brucei

Suramin is one of the first drugs developed in a medicinal chemistry program (Bayer, 1916), and it is still the treatment of choice for the hemolymphatic stage of African sleeping sickness caused by Trypanosoma brucei rhodesiense. Cellular uptake of suramin occurs by endocytosis, and reverse genetic studies with T. b. brucei have linked downregulation of the endocytic pathway to suramin resistance. Here we show that forward selection for suramin resistance in T. brucei spp. cultures is fast, highly reproducible and linked to antigenic variation. Bloodstream-form trypanosomes are covered by a dense coat of variant surface glycoprotein (VSG), which protects them from their mammalian hosts' immune defenses. Each T. brucei genome contains over 2000 different VSG genes, but only one is expressed at a time. An expression switch to one particular VSG, termed VSGSur , correlated with suramin resistance. Reintroduction of the originally expressed VSG gene in resistant T. brucei restored suramin susceptibility. This is the first report of a link between antigenic variation and drug resistance in African trypanosomes

Seebeck coefficients of half-metallic ferromagnets

In this report the Co2 based Heusler compounds are discussed as potential materials for spin voltage generation. The compounds were synthesized by arcmelting and consequent annealing. Band structure calculations were performed and revealed the compounds to be half-metallic ferromagnets. Magnetometry was performed on the samples and the Curie temperatures and the magnetic moments were determined. The Seebeck coefficients were measured from low to ambient temperatures for all compounds. For selected compounds high temperature measurements up to 900 K were performed.Comment: accepted contribution o the Special Issue "Spin Caloritronics" of Solid State Communication

Make your brand heard: A qualitative study on the use of corporate podcasts as a branding tool

As an increasingly popular on-demand medium, podcasts have become more professional and commercialized in recent times. This is also evident from a look at corporate communications, where many companies add podcasts into their communication mix. To align these corporate podcasts with other communication channels, the concept of corporate branding can be helpful. This approach has not been considered by empirical studies so far. Our qualitative interview study wants to investigate the role of corporate podcasts in corporate branding and examines their integration into the communication strategy of nationally and internationally operating companies. 13 experts from large companies responsible for the respective podcast have been interviewed. The research results show that podcasts are mostly integrated into the company’s overarching communications strategy and incorporate company-specific branding aspects to varying degrees. Corporate podcasts are primarily used to highlight innovative and modern aspects of the brands, especially through the tone of voice. The intended impact of corporate podcasts is often a personal and emotional connection, interaction, and resonance with listeners. Increasing reputation, visibility, and conveying authenticity is also targeted. As a branding tool, podcasts are evaluated rather implicitly. The general evaluation is perceived as challenging and tends to focus on qualitative performance measurement. This study underscores the high need for research on corporate podcasts as a branding tool as well as for key performance indicators (KPIs) of podcasts

An Efficient Approach for Quantifying the Mechanical Degradation of Ni‐Rich NMC‐based Cathodes for Lithium‐Ion Batteries using Nano‐XCT Analysis

LiNi$_{0.8}$Co$_{0.1}$Mn$_{0.1}$O$_2$ has emerged as a promising electrode material for automotive lithium-ion batteries due to its high specific discharge capacity, cost-effectiveness, and reduced cobalt content. However, despite all mentioned beneficial attributes, the widespread adoption of this material class is impeded by active material degradation during cycling operation, which is linked to performance loss. This study compares scanning electron microscopy images and nano X-ray computed tomography scans with a 3D reconstruction of pristine and cycle-aged battery electrodes to determine structural changes over cycle life. Although a very moderate current rate was chosen for the cycle test, which suggests a homogeneous load across the entire electrode, particle fracture varied across electrode thickness and particle size. A quantitative analysis of the active material‘s gray scale value distribution reveals severe degradation near the separator interface with a reciprocal relationship to particle radius. Remarkably, particle shape and size remain relatively unchanged despite cracking, eliminating the need to adjust these parameters in aging simulations. Moreover, it underscores the practical significance of particle cracking, as it can significantly impact the electrode‘s performance. Thus, analyzing changes in particle shape and size alone is insufficient, and a comprehensive exploration of the particle interior using nano-XCT is necessary

PyExperimenter: Easily distribute experiments and track results

PyExperimenter is a tool to facilitate the setup, documentation, execution, and subsequent evaluation of results from an empirical study of algorithms and in particular is designed to reduce the involved manual effort significantly. It is intended to be used by researchers in the field of artificial intelligence, but is not limited to those.Comment: Published in Journal of Open Source Softwar

Correlation between leadership style and the use of school performance feedback from state-wide tests

Führung in Schulen wird in diesem Beitrag in die Dimensionen direktiver, diskursiver und delegativer Führungspraktiken differenziert. Diese Differenzierung ist Ausgangspunkt einer explorativen Untersuchung zum Zusammenhang zwischen den Führungsdimensionen und der Nutzung von Ergebnisrückmeldungen aus Vergleichsarbeiten (VERA 8). Bivariate Korrelationsanalysen einer Fragebogenerhebung bei Schulleitungen geben Hinweise darauf, dass die Präferenz bestimmter Führungspraktiken mit Nutzungsweisen von Rückmeldungen durch die Schulleitungen selbst sowie durch weitere schulische Akteure zusammenhängt. Eine direktiv oder diskursiv führende Schulleitung kann die schulische Auseinandersetzung mit VERA eher begünstigen, während eine delegative Schulleitung diese Prozesse eher hemmen kann. (DIPF/Orig.)In this article, we differentiate leadership in the dimensions of a directive, of a dis cursive or of a delegative leadership practice. This differentiation is the starting point of an explorative examination regarding the correlation between leadership dimensions and the use of performance feedback from state-wide tests (VERA 8). Bivariate correlation analyses based on a questionnaire survey with school leaders indicate that particular leadership dimensions correlate with a varied degree of use of performance feedback with different school representatives (e. g., department leaders, teachers). A "directive" or "discursive" leader can support the use of VERA, whereas a "delegative" leader can inhibit these processes. (DIPF/Orig.