31 research outputs found
Integrability of Coupled Conformal Field Theories
The massive phase of two-layer integrable systems is studied by means of RSOS
restrictions of affine Toda theories. A general classification of all possible
integrable perturbations of coupled minimal models is pursued by an analysis of
the (extended) Dynkin diagrams. The models considered in most detail are
coupled minimal models which interpolate between magnetically coupled Ising
models and Heisenberg spin-ladders along the discrete series.Comment: 23 pages, four figure
Integrable quantum field theories with OSP(m/2n) symmetries
We conjecture the factorized scattering description for OSP(m/2n)/OSP(m-1/2n)
supersphere sigma models and OSP(m/2n) Gross Neveu models. The non-unitarity of
these field theories translates into a lack of `physical unitarity' of the S
matrices, which are instead unitary with respect to the non-positive scalar
product inherited from the orthosymplectic structure. Nevertheless, we find
that formal thermodynamic Bethe ansatz calculations appear meaningful,
reproduce the correct central charges, and agree with perturbative
calculations. This paves the way to a more thorough study of these and other
models with supergroup symmetries using the S matrix approach.Comment: 32 pages, 9 figure
Beobachtungen und Folgerungen aus der Katamnese organisch-psychogener Grenzzustände bei Kriegsbeschädigten
Klinisch-experimentelle Untersuchungen �ber die kreislaufdynamischen Wirkungen der dihydrierten Mutterkornalkaloide
European Starlings Are Capable of Discriminating Subtle Size Asymmetries in Paired Stimuli
Small deviations from bilateral symmetry (fluctuating asymmetries) are cues to fitness differences in some animals. Therefore, researchers have considered whether animals use these small asymmetries as visual cues to determine appropriate behavioral responses (e.g., mate preferences). However, there have been few systematic studies of animals' abilities to visually discriminate such minor asymmetries. If the asymmetries cannot be discriminated, fluctuating asymmetry can not be a visual cue. Here, we report an investigation of European starlings' (Sturnus vulgaris) abilities to discriminate small size asymmetries. We trained starlings, through operant conditioning in a free-flight aviary, to discriminate achromatic, symmetric paired stimuli from size-matched asymmetric stimuli. By starting the learning process with a large asymmetry and progressing through sequential trials of decreasing asymmetry, we elucidated a behavioral limit to asymmetry discrimination. We found that starlings are capable of discriminating a 10% size asymmetry. There was weaker evidence for discrimination of 5% asymmetry but no evidence for signal discrimination at 2.5% size asymmetry. This level of asymmetry discrimination suggests that many size asymmetry cues in nature can be discriminated by birds. At each level of asymmetry discrimination, we also tested whether starlings could generalize their learned symmetry preference to unreinforced novel images. Consistent with previous findings, we found that starlings could generalize their symmetry preferences