Fermionic functional renormalization group for first-order phase transitions: a mean-field model

First-order phase transitions in many-fermion systems are not detected in the susceptibility analysis of common renormalization-group (RG) approaches. Here we introduce a counterterm technique within the functional renormalization-group (fRG) formalism which allows access to all stable and metastable configurations. It becomes possible to study symmetry-broken states which occur through first-order transitions as well as hysteresis phenomena. For continuous transitions, the standard results are reproduced. As an example, we study discrete-symmetry breaking in a mean-field model for a commensurate charge-density wave. An additional benefit of the approach is that away from the critical temperature for the breaking of discrete symmetries large interactions can be avoided at all RG scales.Comment: 17 pages, 8 figures. v2 corrects typos, adds references and a discussion of the literatur

Nanocrystalline and stacking-disordered β-cristobalite AlPO4: the now deciphered main constituent of a municipal sewage sludge ash from a full-scale incineration facility

This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.For the first time evidence is provided that a nanocrystalline and stacking-disordered, chemically stabilized β-cristobalite form of AlPO4 occurs in a sewage sludge ash (SSA). This proof is based on a combined X-ray powder diffraction and X-ray fluorescence investigation of an SSA produced at a large-scale fluidized bed incineration facility serving a catching area with a population of 2 million. The structural and chemical characterization was carried out on ‘as received’ SSA samples as well as on solid residues remaining after leaching this SSA in sodium hydroxide solution. Thus, it was ascertained that the observed nanocrystalline and stacking-disordered cristobalite-like component belongs to the aluminum phosphate component of this SSA, rather than to its silicon dioxide component. In addition, a direct proof is presented that the chemically stabilized β-cristobalite form of AlPO4 does crystallize from X-ray amorphous precursors under conditions that mimic the huge heating rate and short retention time (just seconds at T ≈ 850°C), typical for fluidized bed incinerators.Peer Reviewe

Empathy without borders? Cross-cultural heart and mind-reading in first-year medical students

Background: This cross-cultural study was designed to examine cultural differences in empathy levels of first-year medical students.Methods: A total of 257 students from the academic year 2010/11, 131 at Jimma University, Ethiopia, and 126 at the Ludwig Maximilian University, Munich, Germany, completed the Balanced Emotional Empathy Scale (BEES), the Reading the Mind in the Eyes (RME-R) test, and a  questionnaire on sociodemographic and cultural characteristics. Furthermore, we conducted a qualitative analysis of the students’ personal views on the definition of empathy and possible influencing factors. Group comparisons and correlation analyses of empathy scores were performed for the entire cohort and for the Jimma and Munich students separately. We used a regression tree analysis to identify factors influencing the BEES.Results: The male students in Jimma (39.1 ± 22.3) scored significantly higher in the BEES than those male students from Munich (27.2 ± 22.6; p = 0.0002). There was no significant difference between the female groups. We found a moderate, positive correlation between the BEES and RME-R test, i.e. between emotional and cognitive empathy, within each university. Nevertheless, the RME-R test, which shows only Caucasian eyes, appears not to be suitable for use in other cultures.Conclusions: The main findings of our study were the influence of culture, religion, specialization choice, and gender on emotional empathy (assessed with the BEES) and cognitive empathy (assessed with the RME-R test) in first-year medical students. Further research is required into the nature of empathy in worldwide medical curricula.Keywords: Balanced Emotional Empathy Scale, Cross-cultural, Empathy, Medical Student