Interaction control and bright solitons in coherently-coupled Bose-Einstein condensates

We demonstrate fast control of the interatomic interactions in a Bose-Einstein condensate by coherently coupling two atomic states with intra- and inter-state scattering lengths of opposite signs. We measure the elastic and inelastic scattering properties of the system and find good agreement with a theoretical model describing the interactions between dressed states. In the attractive regime, we observe the formation of bright solitons formed by dressed-state atoms. Finally, we study the response of the system to an interaction quench from repulsive to attractive values, and observe how the resulting modulational instability develops into a bright soliton train.Comment: 6 pages, 4 figure

Is attending a mental process?

The nature of attention has been the topic of a lively research programme in psychology for over a century. But there is widespread agreement that none of the theories on offer manage to fully capture the nature of attention. Recently, philosophers have become interested in the debate again after a prolonged period of neglect. This paper contributes to the project of explaining the nature of attention. It starts off by critically examining Christopher Mole’s prominent “adverbial” account of attention, which traces the failure of extant psychological theories to their assumption that attending is a kind of process. It then defends an alternative, process-based view of the metaphysics of attention, on which attention is understood as an activity and not, as psychologists seem to implicitly assume, an accomplishment. The entrenched distinction between accomplishments and activities is shown to shed new light on the metaphysics of attention. It also provides a novel diagnosis of the empirical state of play

Assessment of novel binocular colour, motion and contrast tests in glaucoma

The effects of glaucoma on binocular visual sensitivity for the detection of various stimulus attributes are investigated at the fovea and in four paracentral retinal regions. The study employed a number of visual stimuli designed to isolate the processing of various stimulus attributes. We measured absolute contrast detection thresholds and functional contrast sensitivity by using Landolt ring stimuli. This psychophysical Landolt C-based contrast test of detection and gap discrimination allowed us to test parafoveally at 6 ° from fixation and foveally by employing interleaved testing locations. First-order motion perception was examined by using moving stimuli embedded in static luminance contrast noise. Red/green (RG) and yellow/blue (YB) colour thresholds were measured with the Colour Assessment and Diagnosis (CAD) test, which utilises random dynamic luminance contrast noise (± 45 %) to ensure that only colour and not luminance signals are available for target detection. Subjects were normal controls (n = 65) and glaucoma patients with binocular visual field defects (n = 15) classified based on their Humphrey Field Analyzer mean deviation (MD) scores. The impairment of visual function varied depending on the stimulus attribute and location tested. Progression of loss was noted for all tests as the degree of glaucoma increased. For subjects with mild glaucoma (MD −0.01 dB to −6.00 dB) significantly more data points fell outside the normal age-representative range for RG colour thresholds than for any other visual test, followed by motion thresholds. This was particularly the case for the parafoveal data compared with the foveal data. Thus, a multifaceted measure of binocular visual performance, incorporating RG colour and motion test at multiple locations, might provide a better index for comparison with quality of life measures in glaucoma

Older and Younger Driver Performance at Complex Intersections: Implications for Using Perception-Response Time and Driving Simulation

Older drivers are at increased accident risk at intersections for a variety of maneuvers. To examine why, a study was conducted to assess older driver performance at complex intersections in a driving simulator. The University of Calgary Driving Simulator was used to test healthy older drivers (65-83, M = 71.4) and younger drivers (19-22, M = 20.7). Critical scenarios included the sudden appearance of a pedestrian in an intersection, a lastsecond yellow light, an unexpected change during a left, and a vehicle violating a stoplight. Older drivers had significantly higher perception response times (PRT) than younger drivers for the latter three of the four intersection scenarios. Analysis of specific maneuvers also revealed qualitative response differences between young and old groups. In contradiction to expectation, more older drivers ran the yellow light than younger drivers. The capability of older drivers to respond under time constraints is implicated. The utility of driving simulators to assess older driver performance at intersections was limited by the prevalence of simulator sickness

Older and Younger Driver Performance at Complex Intersections: Implications for Using Perception-Response Time and Driving Simulation

Older drivers are at increased accident risk at intersections for a variety of maneuvers. To examine why, a study was conducted to assess older driver performance at complex intersections in a driving simulator. The University of Calgary Driving Simulator was used to test healthy older drivers (65-83, M = 71.4) and younger drivers (19-22, M = 20.7). Critical scenarios included the sudden appearance of a pedestrian in an intersection, a lastsecond yellow light, an unexpected change during a left, and a vehicle violating a stoplight. Older drivers had significantly higher perception response times (PRT) than younger drivers for the latter three of the four intersection scenarios. Analysis of specific maneuvers also revealed qualitative response differences between young and old groups. In contradiction to expectation, more older drivers ran the yellow light than younger drivers. The capability of older drivers to respond under time constraints is implicated. The utility of driving simulators to assess older driver performance at intersections was limited by the prevalence of simulator sickness

Kelvin mode of a vortex in a nonuniform Bose-Einstein condensate

In a uniform fluid, a quantized vortex line with circulation h/M can support long-wavelength helical traveling waves proportional to e^{i(kz-\omega_k t)} with the well-known Kelvin dispersion relation \omega_k \approx (\hbar k^2/2M) \ln(1/|k|\xi), where \xi is the vortex-core radius. This result is extended to include the effect of a nonuniform harmonic trap potential, using a quantum generalization of the Biot-Savart law that determines the local velocity V of each element of the vortex line. The normal-mode eigenfunctions form an orthogonal Sturm-Liouville set. Although the line's curvature dominates the dynamics, the transverse and axial trapping potential also affect the normal modes of a straight vortex on the symmetry axis of an axisymmetric Thomas-Fermi condensate. The leading effect of the nonuniform condensate density is to increase the amplitude along the axis away from the trap center. Near the ends, however, a boundary layer forms to satisfy the natural Sturm-Liouville boundary conditions. For a given applied frequency, the next-order correction renormalizes the local wavenumber k(z) upward near the trap center, and k(z) then increases still more toward the ends.Comment: 9 pages, 1 figur

Narrative exposure therapy for survivors of human trafficking: feasibility randomised controlled trial

Background Human trafficking is a grave human rights violation and a major public health concern. Survivors present with high rates of mental health problems including post-traumatic stress disorder (PTSD). Studies of effective treatments for PTSD in survivors of human trafficking are lacking. Narrative exposure therapy (NET) is an effective PTSD treatment for multiple, prolonged and complex trauma, but its efficacy has not been rigorously tested in survivors of human trafficking. Aims To test the feasibility and acceptability of a randomised controlled trial (RCT) offering NET as a treatment for PTSD in trafficking survivors with a history of multiple traumatic events, as well as providing preliminary evidence regarding its efficacy (trial registration: ISRCTN95136302). Method A single-blind RCT compared NET with a wait-list control in survivors of trafficking with PTSD (n = 25). In the NET arm of the study, participants attended a mean of 17 sessions. Results NET was well tolerated by participants. There were significant reductions in PTSD, depression and anxiety symptoms post-treatment in the NET group but no significant change in the wait-list group. Conclusions The results indicate that NET is a promising and acceptable treatment for trafficking survivors. Psychological therapy in an RCT design can be safely delivered to this vulnerable group, although modifications are required to ensure their holistic needs are properly addressed

Narrative exposure therapy for survivors of human trafficking: feasibility randomised controlled trial

BACKGROUND: Human trafficking is a grave human rights violation and a major public health concern. Survivors present with high rates of mental health problems including post-traumatic stress disorder (PTSD). Studies of effective treatments for PTSD in survivors of human trafficking are lacking. Narrative exposure therapy (NET) is an effective PTSD treatment for multiple, prolonged and complex trauma, but its efficacy has not been rigorously tested in survivors of human trafficking. AIMS: To test the feasibility and acceptability of a randomised controlled trial (RCT) offering NET as a treatment for PTSD in trafficking survivors with a history of multiple traumatic events, as well as providing preliminary evidence regarding its efficacy (trial registration: ISRCTN95136302). METHOD: A single-blind RCT compared NET with a wait-list control in survivors of trafficking with PTSD (n = 25). In the NET arm of the study, participants attended a mean of 17 sessions. RESULTS: NET was well tolerated by participants. There were significant reductions in PTSD, depression and anxiety symptoms post-treatment in the NET group but no significant change in the wait-list group. CONCLUSIONS: The results indicate that NET is a promising and acceptable treatment for trafficking survivors. Psychological therapy in an RCT design can be safely delivered to this vulnerable group, although modifications are required to ensure their holistic needs are properly addressed

Clustering of Primordial Black Holes. II. Evolution of Bound Systems

Primordial Black Holes (PBHs) that form from the collapse of density perturbations are more clustered than the underlying density field. In a previous paper, we showed the constraints that this has on the prospects of PBH dark matter. In this paper we examine another consequence of this clustering: the formation of bound systems of PBHs in the early universe. These would hypothetically be the earliest gravitationally collapsed structures, forming when the universe is still radiation dominated. Depending upon the size and occupation of the clusters, PBH merging occurs before they would have otherwise evaporated due to Hawking evaporation.Comment: 23 pages, 1 figure. Submitted to PR

'New to me': changing patient understanding of psoriasis and identifying mechanisms of change. The Pso Well® patient materials mixed-methods feasibility study

BACKGROUND: Psoriasis is an inflammatory long-term condition involving comorbidities, unhealthy lifestyle and significant life impact. Patients' understanding of psoriasis is limited and support lacking. The Common-Sense Model of Self-Regulation of Health and Illness emphasizes the role of illness and treatment beliefs on coping and self-management. New 'Pso Well® ' patient materials informed by the model, addressed psoriasis as a long-term condition, medication management and lifestyle behaviours. OBJECTIVES: To investigate whether Pso Well® materials (i) broaden understanding of psoriasis without increasing anxiety; (ii) are acceptable; and (iii) comprise features that appear to effect change. METHODS: The Revised Illness Perceptions Questionnaire (IPQ-R modified) and the Hospital Anxiety and Depression Scale (HADS) were administered in patients before and after intervention. Numerical rating scales assessed perceptions of change in understanding and anxiety resulting from engagement with the materials. Qualitative interviews explored acceptability and perceived 'active ingredients'. RESULTS: Fifty-five patients completed pre- and postintervention questionnaires (56% female; median age 59 years). Postintervention, a large effect size was indicated in two IPQ-R domains - illness coherence [t(55) = -3·48, P = 0·001 (two-tailed), η2  = 0·19] and personal control [t(55) = -2·98, P = 0·004 (two-tailed), η2  = 0·14] - and a medium effect in one, treatment control [t(55) = -2·08, P = 0·042 (two-tailed), η2  = 0·08]. HADS scores did not change. For numerical rating scales, 80% of participants reported increased understanding of psoriasis and none reported increased anxiety. Interviews with 19 patients indicated the materials were acceptable and usable. Factors reported to broaden understanding and promote engagement with self-management included linking of related disease aspects, personally relevant content and high-quality design. CONCLUSIONS: High-quality, theory-based psoriasis materials are acceptable to patients and can improve understanding and sense of control without increasing anxiety