9,590 research outputs found

    Solar Magnetic Tracking. IV. The Death of Magnetic Features

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    The removal of magnetic flux from the quiet-sun photosphere is important for maintaining the statistical steady-state of the magnetic field there, for determining the magnetic flux budget of the Sun, and for estimating the rate of energy injected into the upper solar atmosphere. Magnetic feature death is a measurable proxy for the removal of detectable flux. We used the SWAMIS feature tracking code to understand how nearly 20000 detected magnetic features die in an hour-long sequence of Hinode/SOT/NFI magnetograms of a region of quiet Sun. Of the feature deaths that remove visible magnetic flux from the photosphere, the vast majority do so by a process that merely disperses the previously-detected flux so that it is too small and too weak to be detected. The behavior of the ensemble average of these dispersals is not consistent with a model of simple planar diffusion, suggesting that the dispersal is constrained by the evolving photospheric velocity field. We introduce the concept of the partial lifetime of magnetic features, and show that the partial lifetime due to Cancellation of magnetic flux, 22 h, is 3 times slower than previous measurements of the flux turnover time. This indicates that prior feature-based estimates of the flux replacement time may be too short, in contrast with the tendency for this quantity to decrease as resolution and instrumentation have improved. This suggests that dispersal of flux to smaller scales is more important for the replacement of magnetic fields in the quiet Sun than observed bipolar cancellation. We conclude that processes on spatial scales smaller than those visible to Hinode dominate the processes of flux emergence and cancellation, and therefore also the quantity of magnetic flux that threads the photosphere.Comment: Accepted by Ap

    Laying Down the Foundations for International Student Journey. Students as Academic Partners Project Report.

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    The aim of this project was to explore the lived experiences of being an international student studying at a University within the UK and to make recommendations for future provision. There are increasing numbers of international students studying at Universities within the UK. Positive learning environments and arrangements are the responsibility of the host University and international students’ needs should be taken into consideration. This project was led by international students in collaboration with academic staff. It involved a qualitative exploration of international student perspectives and their experiences of studying within the UK. Ten international students completed a questionnaire that was designed by international students. Respondents were asked questions in relation to three areas: coming to the UK, arriving in the UK and studying in the UK

    Development of an awareness-based intervention to enhance quality of life in severe dementia: trial platform.

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    RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Quality of residential care for people with severe dementia is in urgent need of improvement. One reason for this may be the assumption that people with severe dementia are unaware of what is happening to them. However, there is converging evidence to suggest that global assumptions of unawareness are inappropriate. This trial platform study aims to assist care staff in perceiving and responding to subtle signs of awareness and thus enhance their practice. METHODS/DESIGN: In Stage One, a measure of awareness in severe dementia will be developed. Two focus groups and an expert panel will contribute to item and scale development. In Stage Two observational data will be used to further develop the measure. Working in four care homes, we will recruit 40 individuals with severe dementia who have no, or very limited, verbal communication. Data on inter-rater reliability and frequency of all items and exploratory factor analysis will be used to identify items to be retained. Test-retest and inter-rater reliability for the new measure will be calculated. Correlations with scores for well-being and behaviour and with proxy ratings of quality of life will provide an indication of concurrent validity. In Stage Three the new measure will be used in a single blind cluster randomised trial. Eight care homes will participate, with 10 residents recruited in each giving a total sample of 80 people with severe dementia. Homes will be randomised to intervention or usual care conditions. In the intervention condition, staff will receive training in using the new measure and will undertake observations of designated residents. For residents with dementia, outcomes will be assessed in terms of change from baseline in scores for behaviour, well-being and quality of life. For care staff, outcomes will be assessed in terms of change from baseline in scores for attitudes, care practice, and well-being. DISCUSSION: The results will inform the design of a larger-scale trial intended to provide definitive evidence about the benefits of increasing the sensitivity of care staff to signs of awareness in residents with severe dementia. TRIAL REGISTRATION: ISRCTN59507580 http://www.controlled-trials.com.Published versio

    Calibration and Cross-Validation of Accelerometery for Estimating Movement Skills in Children Aged 8-12 Years

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    This study sought to calibrate triaxial accelerometery, worn on both wrists, waist and both ankles, during children’s physical activity (PA), with particular attention to object control motor skills performed at a fast and slow cadence, and to cross-validate the accelerometer cut-points derived from the calibration using an independent dataset. Twenty boys (10.1 ±1.5 years) undertook seven, five-minute bouts of activity lying supine, standing, running (4.5kmph−1) instep passing a football (fast and slow cadence), dribbling a football (fast and slow cadence), whilst wearing five GENEActiv accelerometers on their non-dominant and dominant wrists and ankles and waist. VO2 was assessed concurrently using indirect calorimetry. ROC curve analysis was used to generate cut-points representing sedentary, light and moderate PA. The cut-points were then cross-validated using independent data from 30 children (9.4 ± 1.4 years), who had undertaken similar activities whilst wearing accelerometers and being assessed for VO2. GENEActiv monitors were able to discriminate sedentary activity to an excellent level irrespective of wear location. For moderate PA, discrimination of activity was considered good for monitors placed on the dominant wrist, waist, non-dominant and dominant ankles but fair for the non-dominant wrist. Applying the cut-points to the cross-validation sample indicated that cut-points validated in the calibration were able to successfully discriminate sedentary behaviour and moderate PA to an excellent standard and light PA to a fair standard. Cut-points derived from this calibration demonstrate an excellent ability to discriminate children’s sedentary behaviour and moderate intensity PA comprising motor skill activity.N/

    Decoherence of a Josephson qubit due to coupling to two level systems

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    Noise and decoherence are major obstacles to the implementation of Josephson junction qubits in quantum computing. Recent experiments suggest that two level systems (TLS) in the oxide tunnel barrier are a source of decoherence. We explore two decoherence mechanisms in which these two level systems lead to the decay of Rabi oscillations that result when Josephson junction qubits are subjected to strong microwave driving. (A) We consider a Josephson qubit coupled resonantly to a two level system, i.e., the qubit and TLS have equal energy splittings. As a result of this resonant interaction, the occupation probability of the excited state of the qubit exhibits beating. Decoherence of the qubit results when the two level system decays from its excited state by emitting a phonon. (B) Fluctuations of the two level systems in the oxide barrier produce fluctuations and 1/f noise in the Josephson junction critical current I_o. This in turn leads to fluctuations in the qubit energy splitting that degrades the qubit coherence. We compare our results with experiments on Josephson junction phase qubits.Comment: 23 pages, Latex, 6 encapsulated postscript figure

    The Ambivalence of Promising Technology

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    Issues of responsibility in the world of nanotechnology are becoming explicit with the emergence of a discourse on ‘responsible development’ of nanoscience and nanotechnologies. Much of this discourse centres on the ambivalences of nanotechnology and of promising technology in general. Actors must find means of dealing with these ambivalences. Actors’ actions and responses to ambivalence are shaped by their position and context, along with strategic games they are involved in, together with other actors. A number of interviews were conducted with industrial actors with the aim of uncovering their ethical stances towards responsible development of nanotechnology. The data shows that standard repertoires of justification of nanotechnological development were used. Thus, the industrial actors fell back on their position and associated responsibilities. Such responses reinforce a division of moral labour in which industrial actors and scientists can focus on the progress of science and technology, while other actors, such as NGOs, are expected to take care of broader considerations, such as ethical and social issues

    Mealtime Behaviour and Parent-Child Interaction: A Comparison of Children with Cystic Fibrosis, Children with Feeding Problems, and Nonclinic Controls

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    Examined the role of family interaction factors in dietary compliance problems reported by parents of children with cystic fibrosis (CF). The family mealtime interactions of children with CF, children with feeding problems and nonclinic controls were observed, and parents monitored children's eating behavior at home. Parents of children with CF reported more concern about feeding problems and recorded more disruptive mealtime behavior than parents of nonclinic children. Observational data showed children with CF to display overall rates of disruptive mealtime behavior not significantly different from either comparison group. Mothers of children with CF were observed to engage in higher rates of aversive interaction with their child than did mothers of nonclinic controls. Fathers of children with CF reported lower marital satisfaction than fathers of controls. Both mothers and fathers of children with CF reported lower parenting self-efficacy than non-CF families. Clinical implications are discussed
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