Quantum spin spiral ground state of the ferrimagnetic sawtooth chain

The ferrimagnetic phase of the sawtooth chain with mixed ferromagnetic nearest-neighbour interactions $J$ and antiferromagnetic next-nearest-neighbour interactions $J'$ (within the isotropic Heisenberg model) was previously characterized as a phase with commensurate order. In this paper, we demonstrate that the system in fact exhibits an incommensurate quantum spin spiral. Even though the ground state is translationally invariant in terms of the local spin expectations \avg{\vec{S}_i}, the spiral can be detected via the connected spin-spin correlations \avg{\vec{S}_i\cdot\vec{S}_j}-\avg{\vec{S}_i}\cdot\avg{\vec{S}_j} between the apical spins. It has a long wavelength that grows with $J'$ and that soon exceeds finite-system sizes typically employed in numerical simulations. A faithful treatment thus requires the use of state-of-the-art simulations for large, periodic systems. In this work, we are able to accurately treat up to $L=400$ sites (200 unit cells) with periodic boundary conditions using the density-matrix renormaliztion group (DMRG). Exploiting the SU(2) symmetry allows us to directly compute the lowest-energy state for a given total spin. Our results are corroborated by variational uniform matrix product state (VUMPS) calculations, which work directly in the thermodynamic limit at the cost of a lower accuracy

Die LUCA Office Simulation in der Lehrerinnen- und Lehrerbildung - didaktische Design-Empfehlungen und erforderliche Lehrkompetenzen

Vor dem Hintergrund einer u. a. durch die Digitalisierung bedingten Verschiebung von Kompetenzanforderungen an Lernende bei gleichzeitig wachsenden digitalen Möglichkeiten an beruflichen Schulen muss nicht nur von einer neuen digitalen Rea- lität beruflicher Lernprozesse, sondern auch von einer neuen Realität beruflicher Lehrprozesse ausgegangen werden. Wie ein digital gestützter Unterricht für die kauf- männische Bildung aussehen kann und welche professionellen Kompetenzen von Lehrkräften hierfür relevant sein könnten, wird am Beispiel der an der Universität Mannheim entwickelten Bürosimulation LUCA1 erörtert. Der Beitrag geht konzeptio- nell-induktiv anhand der LUCA-Funktionen eines konkreten Anwendungsbeispiels sowie Modellen digitaler Lehrkompetenzen der Frage nach, welche Unterrichtskom- petenzen diesbezüglich bei Lehrkräften erforderlich sind. Im Ergebnis werden spezi- fische Aspekte digitaler Unterrichtskompetenz identifiziert, die für die Anwendung virtueller Lernsimulationen, wie der LUCA-Bürosimulation, hilfreich sind

Position statement regarding the current standing of exercise therapy in Austria (Positionspapier zur Situation der Trainingstherapie in Österreich)

In Austria, exercise therapy is an accredited profession that requires academic training on the university master’s level. However, exercise therapy is not listed in the service plans of health and medical insurance funds and is therefore not reimbursed as a health service for patients. This position paper aims to compile the scientific evidence of the efficacy and effectiveness of exercise therapy as a treatment component in medical care. It also informs about the skills and competencies that exercise therapists acquire during their university studies in sport science. Thus, the necessity to include exercise therapy as a health service for patients is argued. Additionally, legal parity for exercise therapists within the healthcare professions offering evidence-based treatment methods is advocated. Numerous studies confirm that exercise therapy clearly leads to improvements in musculoskeletal, internal, neurological, psychiatric, and psychosomatic diseases. Exercise therapy is a highly evidence-based, low-side-effect component of prevention, treatment, and rehabilitation measures for almost all chronic diseases. It has a positive impact on pathogenesis, symptoms, fitness, quality of life, morbidity, and mortality of affected patients. The five-year academic training in sport science for exercise therapists conveys medical, theoretical knowledge, and practical skills on training and exercise, communication-related, sports-, and movement-related skills, as well as a profound education in scientific methodology. Consequently, the integration of exercise as therapeutic treatment into the healthcare system is highly indicated from a medical, societal and economic perspective. A new legal framework offering self-employment regulations for exercise therapists is required

Cytochrome P450 2B6 (CYP2B6) and constitutive androstane receptor (CAR) polymorphisms are associated with early discontinuation of efavirenz-containing regimens

Objectives Cytochrome P450 2B6 (CYP2B6) is responsible for the metabolic clearance of efavirenz and single nucleotide polymorphisms (SNPs) in the CYP2B6 gene are associated with efavirenz pharmacokinetics. Since the constitutive androstane receptor (CAR) and the pregnane X receptor (PXR) correlate with CYP2B6 in liver, and a CAR polymorphism (rs2307424) and smoking correlate with efavirenz plasma concentrations, we investigated their association with early (<3 months) discontinuation of efavirenz therapy. Methods Three hundred and seventy-three patients initiating therapy with an efavirenz-based regimen were included (278 white patients and 95 black patients; 293 male). DNA was extracted from whole blood and genotyping for CYP2B6 (516G → T, rs3745274), CAR (540C → T, rs2307424) and PXR (44477T → C, rs1523130; 63396C → T, rs2472677; and 69789A → G, rs763645) was conducted. Binary logistic regression using the backwards method was employed to assess the influence of SNPs and demographics on early discontinuation. Results Of the 373 patients, 131 withdrew from therapy within the first 3 months. Black ethnicity [odds ratio (OR) = 0.27; P = 0.0001], CYP2B6 516TT (OR = 2.81; P = 0.006), CAR rs2307424 CC (OR = 1.92; P = 0.007) and smoking status (OR = 0.45; P = 0.002) were associated with discontinuation within 3 months. Conclusions These data indicate that genetic variability in CYP2B6 and CAR contributes to early treatment discontinuation for efavirenz-based antiretroviral regimens. Further studies are now required to define the clinical utility of these association

Review: Karin Reiber (2005). Organisation im Spiegel der Regula Benedicti

Seit 1500 Jahren wird das klösterliche Leben der Benediktiner durch Regeln aus der Zeit der ersten Klostergründung bestimmt. Dies lässt auf eine geschichtliche Umbrüche und Veränderungen überdauernde Organisationsstruktur schließen. Ausgehend von einem neuen Verständnis der Organisationsentwicklung als Organisationslernen sucht Karin REIBER durch eine hermeneutische Textanalyse der Regula Benedicti aus dem 6. Jahrhundert nach Hinweisen für Organisationsgestaltung und Organisationslernen. In einer theoretischen Rahmenlegung entwickelt REIBER drei Dimensionen der Organisationsgestaltung und drei Stufen organisationalen Lernens. In einer historischen Rekonstruktion analysiert die Autorin den Text der Regula Benedicti. In einer zweiten Phase rezipiert und interpretiert REIBER die Ergebnisse der hermeneutischen Analyse entlang eines doppelt-dreischrittigen Theoriemodells. Sie arbeitet interessante Aspekte für das Organisationslernen heraus, die individuelles Lernen und organisationales Lernen zu Gunsten des Organisationsmitgliedes in Beziehung setzen, wobei die Rücksichtnahme auf Individualität Teil des Führungskonzeptes ist und als soziales Beziehungsgefüge neben der formalen Struktur eine informelle Organisationsstruktur herausbildet. Die aufschlussreiche Arbeit führt zu einem integrativen Konzept organisationalen Lernens, das Tradition als konstitutives Merkmal einer Organisation um die Innovationsfähigkeit erweitert und so durch Kontinuität und Aktualität den Bestand moderner Organisation in die Zukunft sichern kann.For 1500 years, the monastic life of the Benedictines has been defined by rules dating from the time of the first foundation of the order, suggesting an organizational structure that has outlasted historical upheavals and changes. Starting from a new understanding of organisational development as organisational learning, Karin REIBER has looked for clues to organisational formation and learning through a hermeneutic textual analysis of the Regula Benedicti of the 6th Century. Within a theoretical framework, REIBER develops three dimensions of organisational formation and three stages of organisational learning. In a historical reconstruction, the author analyses the text of the Regula Benedicti. In a second section, REIBER adapts and interprets the results of the hermeneutic analysis through a double three-stage theoretical model. She works out interesting aspects for organisational learning, which relate individual learning to organisational learning in favour of members of the organisation, for which consideration for individuality forms a part of the leadership concept and as a framework for social relationships, establishing an informal organisational structure beside the formal one. This illuminating work leads to an integrated concept of organisational learning, which extends the notion of tradition as a characteristic feature of an innovative organisation and which, through continuity and topicality, can hence guarantee the continued existence of modern organisations in the future.Durante 1500 años, la vida monástica de los Benedictinos se definió mediante reglas que se establecieron en la fundación de la orden, lo que ha dado paso a una estructura organizacional que ha superado cambios y sacudidas. A partir de una nueva visión del desarrollo organizacional como aprendizaje organizativo, Karin REIBER ha buscado pistas para apoyar la formación y el aprendizaje en la organización a través de un análisis textual hermenéutico de la Regla Benedictina del siglo VI. REIBER parte de marco teórico y desarrolla tres dimensiones de la formación en la organización y tres etapas del aprendizaje organizativo. La autora analiza primero el texto de la Regla Benedictina haciendo una reconstrucción histórica. En una segunda sección, REIBER adapta e interpreta los resultados del análisis hermenéutico a través de un modelo teórico de tres etapas. Aporta cuestiones interesantes para el aprendizaje organizacional: relaciona el aprendizaje individual con el aprendizaje que hace la organización en favor de sus miembros; considera las formas de individualidad como una parte del concepto de lideradgo y como un marco para las relaciones sociales; y establece una estructura organizativa informal situada junto a la formal. Este trabajo clarificador conduce a una concepción integrada del aprendizaje organizacional, que extiende la noción de la tradición como un rasgo característico de una organización innovadora y que, siguiendo un continuo que hace de la tradición algo de actualidad, puede garantizar la continuidad de las modernas organizaciones en el futuro