20,460 research outputs found
High-precision measurement of the half-life of Ga
The beta-decay half-life of 62Ga has been studied with high precision using
on-line mass separated samples. The decay of 62Ga which is dominated by a 0+ to
0+ transition to the ground state of 62Zn yields a half-life of T_{1/2} =
116.19(4) ms. This result is more precise than any previous measurement by
about a factor of four or more. The present value is in agreement with older
literature values, but slightly disagrees with a recent measurement. We
determine an error weighted average value of all experimental half-lives of
116.18(4) ms.Comment: 9 pages, 5 figures, accepted for publication in PR
Preparing the foundations for video-based, practice-placement support: establishing the role from a studentsâ perspective
Currently, many placement-based health programme students within the UK are supported through face-to-face visits from university staff. Whilst cited in literature as being of value, the face-to-face nature of this contact is not supported. Alternatives including video-based communications methods offer the potential for cost effective, environmentally responsible support. However, in order to establish the fitness for purpose of alternative approaches, the content and purpose of current support needs to be understood. This project aimed to investigate student perceptions of the ideal content and purpose of clinical support visits, and alternatives to the current face-to-face approach. Fifty-six Physiotherapy undergraduate students responded to questionnaires with a further nine participating in a follow-up focus group. Participants emphasised the value of the visit in guiding learning, ensuring progression and resolving arising issues, and highlighted concerns over alternative approaches. Focus group participants discussed the importance of personal and professional confidence in directing requirements for support, and went on to propose a menu of options for methods of communication.Whilst limited in some applications, video technologies may be one of the options. Overall, however, this project supports the need for consideration of individualised learning journeys within curriculum planning
Stable and Metastable vortex states and the first order transition across the peak effect region in weakly pinned 2H-NbSe_2
The peak effect in weakly pinned superconductors is accompanied by metastable
vortex states. Each metastable vortex configuration is characterized by a
different critical current density J_c, which mainly depends on the past
thermomagnetic history of the superconductor. A recent model [G. Ravikumar, et
al, Phys. Rev. B 61, R6479 (2000)] proposed to explain the history dependent
J_c postulates a stable state of vortex lattice with a critical current density
J_c^{st}, determined uniquely by the field and temperature. In this paper, we
present evidence for the existence of the stable state of the vortex lattice in
the peak effect region of 2H-NbSe_2. It is shown that this stable state can be
reached from any metastable vortex state by cycling the applied field by a
small amplitude. The minor magnetization loops obtained by repeated field
cycling allow us to determine the pinning and "equilibrium" properties of the
stable state of the vortex lattice at a given field and temperature
unambiguously. The data imply the occurence of a first order phase transition
from an ordered phase to a disordered vortex phase across the peak effect.Comment: 20 pages, 10 figures. Corresponding author: S. Ramakrishna
Flow Induced Organization and Memory of a Vortex Lattice
We report on experiments probing the evolution of a vortex state in response
to a driving current in 2H-NbSe crystals. By following the vortex motion
with fast transport measurements we find that the current enables the system to
reorganize and access new configurations. During this process the system
exhibits a long-term memory: if the current is turned off the vortices freeze
in place remembering their prior motion. When the current is restored the
motion resumes where it stopped. The experiments provide evidence for a
dynamically driven structural change of the vortex lattice and a corresponding
dynamic phase diagram that contains a previously unknown regime where the
critical current can be either or by applying an
appropriate driving current.Comment: 5 pages, 4figure
Empirically Driven Use Case Metamodel Evolution
Metamodel evolution is rarely driven by empirical evidences of metamodel
drawbacks. In this paper, the evolution of the use case metamodel used
by the publicly available requirements management tool REM is presented. This
evolution has been driven by the analysis of empirical data obtained during the
assessment of several metricsâbased verification heuristics for use cases developed
by some of the authors and previously presented in other international fora.
The empirical analysis has made evident that some common defects found in
use cases developed by software engineering students were caused not only by
their lack of experience but also by the expressive limitations imposed by the underlying
use case metamodel used in REM. Once these limitations were clearly
identified, a number of evolutionary changes were proposed to the REM use case
metamodel in order to increase use case quality, i.e. to avoid those situations in
which the metamodel were the cause of defects in use case specifications.Ministerio de Ciencia y TecnologĂa TIC 2003-02737-C02-0
Public knowledge, attitudes, social distance and reported contact regarding people with mental illness 2009-2015
Objective To investigate whether public knowledge, attitudes, desire for social distance and reported contact in relation to people with mental health problems have improved in England during the Time to Change (TTC) programme to reduce stigma and discrimination 2009â2015. Methods Using data from an annual face-to-face survey of a nationally representative sample of adults, we analysed longitudinal trends in the outcomes with regression modelling using standardised scores of the measures overall and by age and gender subgroups. Results There were improvements in all outcomes. The improvement for knowledge was 0.17 standard deviation units in 2015 compared to 2009 (95% CI 0.10, 0.23); for attitudes 0.20 standard deviation units (95% CI 0.14, 0.27) and for social distance 0.17 standard deviation units (95% CI 0.11, 0.24). Survey year for 2015 vs. 2009 was associated with a higher likelihood of reported contact (OR 1.32, 95% CI 1.13, 1.53). Statistically significant interactions between year and age suggest the campaign had more impact on the attitudes of the target age group (25â45) than those aged over 65 or under 25. Women's reported contact with people with mental health problems increased more than did men's. Conclusion The results provide support for the effectiveness of TTC
Engagement in activities and occupations by people who have experienced psychosis : a metasynthesis of lived experience
Longer fixation duration while viewing face images
The spatio-temporal properties of saccadic eye movements can be influenced by the cognitive demand and the characteristics of the observed scene. Probably due to its crucial role in social communication, it is argued that face perception may involve different cognitive processes compared with non-face object or scene perception. In this study, we investigated whether and how face and natural scene images can influence the patterns of visuomotor activity. We recorded monkeysâ saccadic eye movements as they freely viewed monkey face and natural scene images. The face and natural scene images attracted similar number of fixations, but viewing of faces was accompanied by longer fixations compared with natural scenes. These longer fixations were dependent on the context of facial features. The duration of fixations directed at facial contours decreased when the face images were scrambled, and increased at the later stage of normal face viewing. The results suggest that face and natural scene images can generate different patterns of visuomotor activity. The extra fixation duration on faces may be correlated with the detailed analysis of facial features
- âŠ