Time-Optimal Transfer of Coherence

We provide exact analytical solutions for the problem of time-optimal transfer of coherence from one spin polarization to a three-fold coherence in a trilinear Ising chain with a fixed energy available and subject to local controls with a non negligible time cost. The time of transfer is optimal and consistent with a previous numerical result obtained assuming instantaneous local controls.Comment: Published version (with typos in eqs. (25)-(27) corrected

A socio-cultural perspective on the first year of teaching secondary mathematics

The purpose of this study was to investigate the experiences of a group of four beginning secondary mathematics teachers in their first year of teaching. Each teacher was interviewed individually for approximately 30 minutes in the middle of the school year. The interview responses were analysed in terms of the participants’ views of themselves as teachers and the factors which they identified as influencing their classroom practices. The study indicates that the culture of the school and the practices of more experienced teachers were important factors in the beginning teachers’ perception of themselves as effective teachers.8 page(s

Different spatial representations guide eye and hand movements

Our visual system allows us to localize objects in the world and plan motor actions toward them. We have recently shown that the localization of moving objects differs between perception and saccadic eye movements (Lisi & Cavanagh, 2015), suggesting different localization mechanisms for perception and action. This finding, however, could reflect a unique feature of the saccade system rather than a general dissociation between perception and action. To disentangle these hypotheses, we compared object localization between saccades and hand movements. We flashed brief targets on top of double-drift stimuli (moving Gabors with the internal pattern drifting orthogonally to their displacement, inducing large distortions in perceived location and direction) and asked participants to point or make saccades to them. We found a surprising difference between the two types of movements: Although saccades targeted the physical location of the flashes, pointing movements were strongly biased toward the perceived location (about 63% of the perceptual illusion). The same bias was found when pointing movements were made in open-loop conditions (without vision of the hand). These results indicate that dissociations are present between different types of actions (not only between action and perception) and that visual processing for saccadic eye movements differs from that for other actions. Because the position bias in the double-drift stimulus depends on a persisting influence of past sensory signals, we suggest that spatial maps for saccades might reflect only recent, short-lived signals, and the spatial representations supporting conscious perception and hand movements integrate visual input over longer temporal intervals

Guided self-help cognitive behavioral intervention for VoicEs (GiVE): study protocol for a pilot randomized controlled trial

Background: Cognitive behavior therapy for psychosis (CBTp) is an effective intervention for people who hear distressing voices (auditory hallucinations). However, there continues to be a problem of poor access to CBTp. Constraints on health care funding require this problem to be addressed without a substantial increase in funding. One solution is to develop guided self-help forms of CBTp to improve access, and a symptom-specific focus on, for example, distressing voices (auditory verbal hallucinations) has the potential to enhance effectiveness. We term this cognitive behavior therapy for distressing voices (CBTv). Methods/design: This trial is an external pilot randomized controlled trial comparing the effects of 12 week guided self-help CBTv (with eight therapist support sessions) with a wait list control condition. Informed consent will be obtained from each participant. Half of the 30 participants will be randomized to receive guided self-help CBTv immediately; the remaining half will receive the intervention after a 12-week delay. All participants will continue with their usual treatment throughout the study. Outcomes will be assessed using questionnaires completed at baseline and 12 weeks postrandomization. Interviews will be offered to all those who receive therapy immediately to explore their experiences with the intervention. Discussion: The outcomes of this trial, both quantitative and qualitative, will inform the design of a definitive randomized controlled trial of guided self-help CBTv. If this intervention is effective, it could help to increase access to CBT for those who hear distressing voices

Muffled price signals: Household water demand under increasing-block prices

In many areas of the world, including large parts of the United States, scarce water supplies are a serious resource and environmental concern. The possibility exists that water is being used at rates that exceed what would be dictated by efficiency criteria, particularly when externalities are taken into account. Because of this, much attention has been given by policy makers and others to the use of various techniques of demand management, including requirements for the adoption of specific technologies and restrictions on particular uses. A natural question for economists to ask is whether price would be a more effective instrument to facilitate efficient management of water resources. As a first step in such an investigation, this paper draws upon a newly available set of detailed data to estimate econometrically the demand function for household use of urban water supplies. Because of the diverse multiple-block pricing structures that abound, estimation of this relationship poses some challenging and interesting problems