A Map of Common Knowledge Logics

In order to capture the concept of common knowledge, various extensions of multi-modal epistemic logics, such as fixed-point ones and infinitary ones, have been proposed. Although we have now a good list of such proposed extensions, the relationships among them are still unclear. The purpose of this paper is to draw a map showing the relationships among them. In the propositional case, these extensions turn out to be all Kripke complete and can be comparable in a meaningful manner. F. Wolter showed that the predicate extension of the Halpern-Moses fixed-point type common knowledge logic is Kripke incomplete. However, if we go further to an infinitary extension, Kripke completeness would be recovered. Thus there is some gap in the predicate case. In drawing the map, we focus on what is happening around the gap in the predicate case. The map enables us to better understand the common knowledge logics as a whole.     

Validation of a Japanese Version of the Work Engagement Scale for Students

We sought to verify the reliability and validity of the Japanese version of the Utrecht Work Engagement Scale for Students (UWES‐S‐J). We examined 824 university students. We calculated the goodness of fit for a single‐factor model and the three‐factor model. The fit to the data was better for the three‐factor than for the single‐factor model, but all factors were highly positively correlated. Additionally, the UWES‐S‐J had good internal consistency and test–retest reliability. For the content validity, there were significant positive correlations between the UWES‐S‐J score and social support, a resilience scale, and subjective happiness. The UWES‐S‐J has good reliability and validity and may therefore be used to assess study engagement among Japanese students.     

Morphological changes in dendritic spines of Purkinje cells associated with motor learning

Experience-dependent changes of spine structure and number may contribute to long-term memory storage. Although several studies demonstrated structural spine plasticity following associative learning, there is limited evidence associating motor learning with alteration of spine morphology. Here, we investigated this issue in the cerebellar Purkinje cells using high voltage electron microscopy (HVEM). Adult rats were trained in an obstacle course, demanding significant motor coordination to complete. Control animals either traversed an obstacle-free runway or remained sedentary. Quantitative analysis of spine morphology showed that the density and length of dendritic spines along the distal dendrites of Purkinje cells were significantly increased in the rats that learned complex motor skills compared to active or inactive controls. Classification of spines into shape categories indicated that the increased spine density and length after motor learning was mainly attributable to an increase in thin spines. These findings suggest that motor learning induces structural spine plasticity in the cerebellar Purkinje neurons, which may play a crucial role in acquiring complex motor skills.     

Perceptual completion of a sound with a short silent gap

Listeners reported the perceptual completion of a sound in stimuli consisting of two crossing frequency glides of unequal duration that shared a short silent gap (40 ms or less) at their crossing point. Even though both glides shared the gap, it was consistently perceived only in the shorter glide, whereas the longer glide could be perceptually completed. Studies on perceptual completion in the auditory domain reported so far have shown that completion of a sound with a gap occurs only if the gap is filled with energy from another sound. In the stimuli used here, however, no such substitute energy was present in the gap, showing evidence for perceptual completion of a sound without local stimulation ('modal' completion). Perceptual completion of the long glide occurred under both monaural and dichotic presentation of the gap-sharing glides; it therefore involves central stages of auditory processing. The inclusion of the gap in the short glide, rather than in both the long and the short glide, is explained in terms of auditory event and stream formation.     

Roles for Drosophila mushroom body neurons in olfactory learning and memory

Olfactory learning assays in Drosophila have revealed that distinct brain structures known as mushroom bodies (MBs) are critical for the associative learning and memory of olfactory stimuli. However, the precise roles of the different neurons comprising the MBs are still under debate. The confusion surrounding the roles of the different neurons may be due, in part, to the use of different odors as conditioned stimuli in previous studies. We investigated the requirements for the different MB neurons, specifically the alpha/beta versus the gamma neurons, and whether olfactory learning is supported by different subsets of MB neurons irrespective of the odors used as conditioned stimuli. We expressed the rutabaga (rut)-encoded adenylyl cyclase in either the gamma or alpha/beta neurons and examined the effects on restoring olfactory associative learning and memory of rut mutant flies. We also expressed a temperature-sensitive shibire (shi) transgene in these neuron sets and examined the effects of disrupting synaptic vesicle recycling on Drosophila olfactory learning. Our results indicate that although we did not detect odor-pair-specific learning using GAL4 drivers that primarily express in gamma neurons, expression of the transgenes in a subset of alpha/beta neurons resulted in both odor-pair-specific rescue of the rut defect as well as odor-pair-specific disruption of learning using shi(ts1).     

An electrophysiological comparison of visual categorization and recognition memory

Object categorization emphasizes the similarities that bind exemplars into categories, whereas recognition memory emphasizes the specific identification of previously encountered exemplars. Mathematical modeling has highlighted similarities in the computational requirements of these tasks, but neuropsychological research has suggested that categorization and recognition may depend on separate brain systems. Following training with families of novel visual shapes (blobs), event-related brain potentials (ERPs) were recorded during both categorization and recognition tasks. ERPs related to early visual processing (N1, 156–200 msec) were sensitive to category membership. Middle latency ERPs (FN400 effects, 300–500 msec) were sensitive to both category membership and old/new differences. Later ERPs (parietal effects, 400–800 msec) were primarily affected by old/new differences. Thus, there was a temporal transition so that earlier processes were more sensitive to categorical discrimination and later processes were more sensitive to recognition-related discrimination. Aspects of these results are consistent with both mathematical modeling and neuropsychological perspectives.     

A model for achievement motives, goal orientations, intrinsic interest, and academic achievement

This study investigated the effects of approach and avoidance achievement motives (the motive to achieve success and the motive to avoid failure) on three goal orientations (mastery, performance-approach, performance-avoidance goals) and the effects of goal orientations on intrinsic interest in learning and academic achievement for 157 tenth and 135 eleventh grade students of a Japanese girls' high school. Structural equation modeling indicated that mastery goals arose mainly from the motive to achieve success; however, the positive relation between the motive to avoid failure and mastery goals was also found. Performance-approach goals were related both the motive to achieve success and the motive to avoid failure. Performance-avoidance goals arouse mainly from the motive to avoid failure; however, the positive relation between the motive to achieve success and these goals was found. Mastery goals positively correlated with intrinsic interest and academic achievement, and scores on both performance-approach goals and performance-avoidance goals had no significant effects on either intrinsic or academic achievement.     

Tuning into the psychotic wavelength: Psychoanalytic supervision for mental health professionals

In this paper, material is presented from supervision groups run for mental health professionals in different mental health settings. I will argue that a psychoanalytic framework, which puts the transference and countertransference at the centre of clinical practice, offers an important model for thinking about psychosis and psychotic means of communication. When staff are able to ‘tune in’ to their patients' communications it can help to change a patient's monologue about his/her delusional world into a meaningful dialogue about their emotional world.     

Novel long-period stacking-ordered structure of martensite in zirconium–cobalt–palladium alloys

A novel long-period stacking-ordered (LPSO) structure of a martensitic phase in a Zr–Co–Pd alloy was discovered and characterized by means of conventional transmission electron microscopy and high-angle annular dark-field scanning transmission electron microscopy. The new phase had a 6O structure and its lattice parameters were estimated to be a = 0.34, b = 0.45 and c = 1.53 nm. The formation mechanism and the space group of the LPSO structure are described.