Field induced phase transitions in the helimagnet Ba2CuGe2O7

We present a theoretical study of the two-dimensional spiral antiferromagnet Ba2CuGe2O7 in the presence of an external magnetic field. We employ a suitable nonlinear sigma model to calculate the T=0 phase diagram and the associated low-energy spin dynamics for arbitrary canted fields, in general agreement with experiment. In particular, when the field is applied parallel to the c axis, a previously anticipated Dzyaloshinskii-type incommensurate-to-commensurate phase transition is actually mediated by an intermediate phase, in agreement with our earlier theoretical prediction confirmed by the recent observation of the so-called double-k structure. The sudden pi/2 rotations of the magnetic structures observed in experiment are accounted for by a weakly broken U(1) symmetry of our model. Finally, our analysis suggests a nonzero weak-ferromagnetic component in the underlying Dzyaloshinskii-Moriya anisotropy, which is important for quantitative agreement with experiment.Comment: 17 pages, 14 figures. Corrected typos in the abstrac

Artikulations- und Intonationsveränderungen als Ausdrucksweisen der sozialen Distanz : (soziale Funktionen phonostilistischer Merkmale in der Konversation)

Die Beschreibungen der phonologischen und phonetischen Gebrauchsmerkmale erschöpfen sich aus der Sicht der informellen Kommunikation bekanntlich vorwiegend in den sprecherbezogenen phonologischen Prozessen, die dominant mit einer durch natürliches Sprechtempo bedingten ausspracheerleichternden Funktion einhergehen. Auch verfügt die moderne Interaktionslinguistik über Kenntnisse einiger linguistischer Funktionen von Intonation. Dennoch wissen wir immer noch sehr wenig über die soziale (d. h. auch strategische) Funktionalität der artikulatorischen und prosodischen (also der segmentalen und suprasegmentalen) Merkmale im Gesprächsverhalten. Dieser Beitrag setzt sich zum Ziel, die kontextsensitiven konversationsphonologischen Sprachmerkmale und ihre soziale Funktionsweise im Alltagsgespräch zu skizzieren. Die Problematik der Herangehensweise an die Erfassung der sozialen Bedeutung von konversationeller Phonetik, Phonologie und Prosodie wird anhand von drei exemplarischen Analysen der Kontextualisierung der sozialen Distanz in den Gesprächen bei verschiedenen informellen Gruppen Jugendlicher beleuchtet

When They Are Gone: How We Grieve

Dr. Chovan reflects on his roots through the lens of grief.https://digitalcommons.otterbein.edu/is/1000/thumbnail.jp

The importance of efficient designs in discrete choice experiments for environmental valuation

Master in Economics: Empirical Applications and Policies. Academic Year 2021-2022.Discrete Choice Experiments (DCEs) are considered to be an appealing approach that is nowadays frequently used among researchers in many fields. No exception is their application in the field of environmental valuation, where we usually deal with relatively small sample sizes. This Master thesis analyzes the efficiency of different experimental designs used in DCEs. Moreover, it tries to examine the effect of prior parameter values in generation of efficient designs for a DCE. All the results are applied on a real case study devoted to climate change adaptations of winemakers in the Rioja region, Spain. The results are obtained through simulation exercises, which are emphasized to be crucial for checking our statistical design before conducting a DCE. The conclusions highlight the use of a specific method to set the prior parameter values necessary for the generation of an efficient design. Finally, the simulation exercises also draw conclusions regarding the trustworthiness of results obtained in the real case study