796 research outputs found
Lattice model of three-dimensional topological singlet superconductor with time-reversal symmetry
We study topological phases of time-reversal invariant singlet
superconductors in three spatial dimensions. In these particle-hole symmetric
systems the topological phases are characterized by an even-numbered winding
number . At a two-dimensional (2D) surface the topological properties of
this quantum state manifest themselves through the presence of flavors of
gapless Dirac fermion surface states, which are robust against localization
from random impurities. We construct a tight-binding model on the diamond
lattice that realizes a topologically nontrivial phase, in which the winding
number takes the value . Disorder corresponds to a (non-localizing)
random SU(2) gauge potential for the surface Dirac fermions, leading to a
power-law density of states . The bulk
effective field theory is proposed to be the (3+1) dimensional SU(2) Yang-Mills
theory with a theta-term at .Comment: 5 pages, 3 figure
Case report: Infection with Dicrocoelium dendriticum in a Japanese Chin dog
Dicrocoelium dendriticum is a trematode colonising the bile ducts of herbivores. Coproscopic findings in dogs are usually considered gastrointestinal passages of eggs after ingestion of unheated liver tissue or infected ruminant faeces. Here, a Japanese Chin presented with diarrhoea and weight loss. Eggs comparable to D. dendriticum were detected in faeces and infection was confirmed via PCR and by ruling out differential diagnoses. Egg excretion continued for a period of 10 months. Praziquantel (50 mg/kg body weight [BW]) was administered orally for four consecutive days. Egg excretion 10 days after treatment entailed further treatments with 100 mg/kg BW, again for four days. Faecal samples were negative ten days and four weeks afterwards, diarrhoea resolved, and the dog gained weight. In cases of repeated coproscopic positivity for D. dendriticum, an infection with dogs acting as definitive hosts should be considered. Treatment with praziquantel at a higher dosage may be required
Facharztweiterbildung Psychiatrie und Psychotherapie: Problemorientiertes Lernen - Evaluation eines Modellprojekts
Zusammenfassung: Die Betonung individueller Lernbedürfnisse, der Fähigkeit zur Lösung komplexer klinischer Probleme sowie einer von interkollegialer Kommunikation geprägten professionellen Grundhaltung durch das problemorientierte Lernen (POL) spricht für dessen Eignung als didaktisches Format in der Facharztweiterbildung. Dennoch wurde es bisher selten hierfür eingesetzt. Im Rahmen dieses Modellprojektes wurde das POL in das Kurrikulum der strukturierten Facharztweiterbildung Psychiatrie und Psychotherapie aufgenommen und über einen Zeitraum von 12Monaten mittels strukturierter Fragebögen evaluiert. Es fanden im Evaluationszeitraum 41POL-Kurse statt, an denen insgesamt 447 Assistenzärzte teilnahmen. Die Teilnehmer und die Tutoren bewerteten 19 von 21 erfragten Aspekten der POL-Kurse als gut bis sehr gut (Mittelwert auf einer 5-stufigen Likert-Skala >4). Insgesamt wurde das POL als besonders geeignet für die Weiterbildung eingeschätzt (Teilnehmer 4,5±0,8; Tutoren 5,0±0,2). Die Ergebnisse dieses Modellprojekts sprechen für die Eignung des POL als Teil eines vielfältigen Weiterbildungsangebots, um den Praxisbezug und die Anwendbarkeit des Wissens im klinischen Alltag zu stärke
Electromagnetic and gravitational responses and anomalies in topological insulators and superconductors
One of the defining properties of the conventional three-dimensional
("-", or "spin-orbit"-) topological insulator is its
characteristic magnetoelectric effect, as described by axion electrodynamics.
In this paper, we discuss an analogue of such a magnetoelectric effect in the
thermal (or gravitational) and the magnetic dipole responses in all symmetry
classes which admit topologically non-trivial insulators or superconductors to
exist in three dimensions. In particular, for topological superconductors (or
superfluids) with time-reversal symmetry which lack SU(2) spin rotation
symmetry (e.g. due to spin-orbit interactions), such as the B phase of He,
the thermal response is the only probe which can detect the non-trivial
topological character through transport. We show that, for such topological
superconductors, applying a temperature gradient produces a thermal- (or mass-)
surface current perpendicular to the thermal gradient. Such charge, thermal, or
magnetic dipole responses provide a definition of topological insulators and
superconductors beyond the single-particle picture. Moreover we find, for a
significant part of the 'ten-fold' list of topological insulators found in
previous work in the absence of interactions, that in general dimensions the
effective field theory describing the space-time responses is governed by a
field theory anomaly. Since anomalies are known to be insensitive to whether
the underlying fermions are interacting or not, this shows that the
classification of these topological insulators is robust to adiabatic
deformations by interparticle interactions in general dimensionality. In
particular, this applies to symmetry classes DIII, CI, and AIII in three
spatial dimensions, and to symmetry classes D and C in two spatial dimensions.Comment: 16 pages, 2 figure
Different Forces, Same Consequence: Conscientiousness and Competence Beliefs are Independent Predictors of Academic Effort and Achievement
Conscientiousness and domain-specific competence beliefs are known to be highly important predictors of academic effort and achievement. Given their basis in distinct research traditions, however, these constructs have rarely been examined simultaneously. Three studies with 571, 415, and 1,535 students, respectively, found a moderate association between conscientiousness and competence beliefs, but competence beliefs meaningfully predicted both conscientiousness and academic effort, irrespective of how academic effort was measured (student report or diary data). The associations of competence beliefs with academic effort were highly domain specific, whereas conscientiousness was predictive of academic effort across a wide range of academic subjects. Conscientiousness and competence beliefs were also associated with academic achievement. Cognitive ability, although associated with academic achievement, only loosely predicted academic effort
Combinatorial Properties of Triangle-Free Rectangle Arrangements and the Squarability Problem
We consider arrangements of axis-aligned rectangles in the plane. A geometric
arrangement specifies the coordinates of all rectangles, while a combinatorial
arrangement specifies only the respective intersection type in which each pair
of rectangles intersects. First, we investigate combinatorial contact
arrangements, i.e., arrangements of interior-disjoint rectangles, with a
triangle-free intersection graph. We show that such rectangle arrangements are
in bijection with the 4-orientations of an underlying planar multigraph and
prove that there is a corresponding geometric rectangle contact arrangement.
Moreover, we prove that every triangle-free planar graph is the contact graph
of such an arrangement. Secondly, we introduce the question whether a given
rectangle arrangement has a combinatorially equivalent square arrangement. In
addition to some necessary conditions and counterexamples, we show that
rectangle arrangements pierced by a horizontal line are squarable under certain
sufficient conditions.Comment: 15 pages, 13 figures, extended version of a paper to appear at the
International Symposium on Graph Drawing and Network Visualization (GD) 201
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