Exploration of auditory P50 gating in schizophrenia by way of difference waves

Electroencephalographic measures of information processing encompass both mid-latency evoked potentials like the pre-attentive auditory P50 potential and a host of later more cognitive components like P300 and N400. Difference waves have mostly been employed in studies of later event related potentials but here this method along with low frequency filtering is applied exploratory on auditory P50 gating data, previously analyzed in the standard format (reported in Am J Psychiatry 2003, 160:2236-8). The exploration was motivated by the observation during visual peak detection that the AEP waveform was different in the patient group, although this was not reflected by the peak measures. The sample included un-medicated schizophrenia spectrum patients (n = 17) and healthy controls (n = 24). The patients had an attenuated difference P50. This attenuation was primarily seen in the sub-sample of patients with severe negative symptoms. The difference attenuation was due to low amplitude at the first stimulus. This suggests an abnormality in readiness more than an abnormality in gating in the patient group

Phase transitions and anomalous normal state in superconductors with broken time reversal symmetry

Using Monte Carlo simulations, we explore the phase diagram and the phase transitions in \groupUZ $n$-band superconductors with spontaneously broken time-reversal symmetry (also termed $s+is$ superconductors), focusing on the three-band case. In the limit of infinite penetration length, the system under consideration can, for a certain parameter regime, have a single first order phase transition from a \groupUZ broken state to a normal state due to a nontrivial interplay between \groupU vortices and \groupZ domain walls. This regime may also apply to multicomponent superfluids. For other parameters, when the free energy of the domain walls is low, the system undergoes a restoration of broken \groupZ time reversal symmetry at temperatures lower than the temperature of the superconducting phase transition.{We show that inclusion of fluctuations can strongly suppress the temperature of the \groupZ-transition when frustration is weak. The main result of our paper is that} for relatively short magnetic field penetration lengths, the system has a superconducting phase transition at a temperature lower than the temperature of the restoration of the broken \groupZ symmetry. Thus, there appears a new phase which is \groupU-symmetric, but breaks \groupZ time reversal symmetry, an anomalous dissipative (metallic) state.Comment: 12 pages, 12 figures, submitted to Physical Review

The Performance of Pictorialist Dance Photography

Looking to the widely disseminated pictorialist photos of Waldemar Eide (Norway) and Henry B. Goodwin (Sweden) featuring the Russian ballerina Vera Fokina and the Swedish ballerina Jenny Hasselquist, the article is an enquiry into the role of the dancer in the pictorialist studio and the contribution of pictorialist photography to the turning point when the aesthetics of dance was being re-considered, the dancing body reconfigured, and photography emerged into an art form in its own right. Taking inspiration from the socio-material approach of photography historian Elizabeth Edwards, the analysis downplays the question of content in favor of a focus on the material practices in the photographic studio at the level of the photographer as well as the dancer-model posing before the camera. Placed within a discourse of new materialism, performance and performativity, it moreover considers the resulting photos as material objects that perform in continuing processes of meaning production. An example of the latter discussed at the end of the text is Harald Giersing’s abstract painting ’The Dancer’ based on a photo of Jenny Hasselquist as The Dying Swan