2,778 research outputs found

    Possibility of the new type phase transition

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    The scalar field theory and the scalar electrodynamics quantized in the flat gap are considered. The dynamical effects arising due to the boundary presence with two types of boundary conditions (BC) satisfied by scalar fields are studied. It is shown that while the Neumann BC lead to the usual scalar field mass generation, the Dirichlet BC give rise to the dynamical mechanism of spontaneous symmetry breaking. Due to the later, there arises the possibility of the new type phase transition from the normal to spontaneously broken phase. The decreasing in the characteristic size of the quantization region (the gap size here) and increasing in the temperature compete with each other, tending to transport the system in the spontaneously broken and in the normal phase, respectively. The system evolves with a combined parameter, simultaneously reflecting the change in temperature and in the size. As a result, at the critical value of this parameter there occurs the phase transition from the normal phase to the spontaneously broken one. In particular, the usual massless scalar electrodynamics transforms to the Higgs model

    The introduction, deployment and impact of assistant practitioners in diagnostic radiography in Scotland

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    This article describes the outcomes of an evaluation of the impact of introducing Assistant Practitioners (AP) roles into imaging departments in 13 of the 14 NHS Boards in Scotland. Between 2006 and 2009 some 34 individuals were trained as APs in diagnostic radiography with 33 subsequently taking up AP posts. In 2010 NHS Education for Scotland commissioned an evaluation of the impact brought about through introduction of the diagnostic imaging AP role in imaging departments. The research found that a minority of the managers had considered the workforce implications of introducing the new roles or the supervisory arrangements that would be required. In some sites implementation of the roles had resulted in the release of radiographers for additional training and higher level activities, but in others financial constraints had limited such initiatives. Managers believed that APs had helped maintain or improve service capacity and quality

    Naturalness and Higgs Decays in the MSSM with a Singlet

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    The simplest extension of the supersymmetric standard model - the addition of one singlet superfield - can have a profound impact on the Higgs and its decays. We perform a general operator analysis of this scenario, focusing on the phenomenologically distinct scenarios that can arise, and not restricting the scope to the narrow framework of the NMSSM. We reexamine decays to four b quarks and four tau's, finding that they are still generally viable, but at the edge of LEP limits. We find a broad set of Higgs decay modes, some new, including those with four gluon final states, as well as more general six and eight parton final states. We find the phenomenology of these scenarios is dramatically impacted by operators typically ignored, specifically those arising from D-terms in the hidden sector, and those arising from weak-scale colored fields. In addition to sensitivity of m_Z, there are potential tunings of other aspects of the spectrum. In spite of this, these models can be very natural, with light stops and a Higgs as light as 82 GeV. These scenarios motivate further analyses of LEP data as well as studies of the detection capabilities of future colliders to the new decay channels presented.Comment: 3 figures, 1 appendix; version to appear in JHEP; typos fixed and additional references and acknowledgements adde

    Application of remote sensing to state and regional problems

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    The author has identified the following significant results. The Lowndes County data base is essentially complete with 18 primary variables and 16 proximity variables encoded into the geo-information system. The single purpose, decision tree classifier is now operational. Signatures for the thematic extraction of strip mines from LANDSAT Digital data were obtained by employing both supervised and nonsupervised procedures. Dry, blowing sand areas of beach were also identified from the LANDSAT data. The primary procedure was the analysis of analog data on the I2S signal slicer

    The Triple Higgs Boson Self-Coupling at Future Linear e+e- Colliders Energies: ILC and CLIC

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    We analyzed the triple Higgs boson self-coupling at future e+ee^{+}e^{-} colliders energies, with the reactions e+ebbˉHH,ttˉHHe^{+}e^{-}\to b \bar b HH, t \bar t HH. We evaluate the total cross-sections for both bbˉHHb\bar bHH and ttˉHHt\bar tHH, and calculate the total number of events considering the complete set of Feynman diagrams at tree-level. We vary the triple coupling κλ3H\kappa\lambda_{3H} within the range κ=1\kappa=-1 and +2. The numerical computation is done for the energies expected to be available at a possible Future Linear e+ee^{+}e^{-} Collider with a center-of-mass energy 800,1000,1500800, 1000, 1500 GeVGeV and a luminosity 1000 fb1fb^{-1}. Our analysis is also extended to a center-of-mass energy 3 TeVTeV and luminosities of 1000 fb1fb^{-1} and 5000 fb1fb^{-1}. We found that for the process e+ebbˉHHe^{+}e^{-}\to b \bar b HH, the complete calculation differs only by 3% from the approximate calculation e+eZHH(Zbbˉ)e^{+}e^{-}\to ZHH(Z\to b\bar b), while for the process e+ettˉHHe^{+}e^{-}\to t \bar tHH, the expected number of events, considering the decay products of both tt and HH, is not enough to obtain an accurate determination of the triple Higgs boson self-coupling.Comment: 19 pages, 12 figure

    Probing the Higgs mechanism via γγW+W\gamma\gamma\to W^+W^-

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    We investigate the sensitivity of the reaction γγW+W\gamma\gamma\to W^+W^- to the Higgs sector based on the complete one-loop corrections in the minimal Standard Model and the gauged non-linear σ\sigma-model. While this sensitivity is very strong for the suppressed cross-section of equally polarized photons and longitudinal W bosons, it is only marginal for the dominant mode of transverse polarizations. The corrections within the σ\sigma-model turn out to be UV-finite in accordance with the absence of \log\MH terms in the Standard Model with a heavy Higgs boson.Comment: 12 pages uuencoded postscrip

    Application of remote sensing to state and regional problems

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    There are no author-identified significant results in this report

    Zero Temperature Properties of RNA Secondary Structures

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    We analyze different microscopic RNA models at zero temperature. We discuss both the most simple model, that suffers a large degeneracy of the ground state, and models in which the degeneracy has been remove, in a more or less severe manner. We calculate low-energy density of states using a coupling perturbing method, where the ground state of a modified Hamiltonian, that repels the original ground state, is determined. We evaluate scaling exponents starting from measurements of overlaps and energy differences. In the case of models without accidental degeneracy of the ground state we are able to clearly establish the existence of a glassy phase with θ1/3\theta \simeq 1/3.Comment: 20 pages including 9 eps figure

    Filling the intervention gap: service evaluation of an intensive nonsurgical weight management programme for severe and complex obesity

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    Background: Weight management including formula total diet replacement (TDR) is emerging as an effective intervention for severe and complex obesity, particularly with respect to type 2 diabetes (T2DM). However, no prospective audit and service evaluation of such programmes have been reported. Methods: Following initial feasibility piloting, the Counterweight‐Plus programme was commissioned across a variety of healthcare providers. The programme includes: Screening, TDR (formula low energy diet), food reintroduction and weight loss maintenance, all delivered by staff with 8 h of training, in‐service mentoring, ongoing specialist support and access to medical consultant expertise. Anonymised data are returned centrally for clinical evaluation. Results: Up to December 2016, 288 patients commenced the programme. Mean (SD) baseline characteristics were: age 47.5 (12.7) years, weight 128.0 (32.0) kg, body mass index 45.7 (10.1) kg m−2, n = 76 (26.5%) were male and n = 99 (34.5%) had T2DM. On an intention‐to‐treat (ITT) basis, a loss of ≥15 kg at 12 months was achieved by 48 patients, representing 22.1% of all who started and 40% of those who maintained engagement. For complete cases, mean (95% confidence interval) weight loss was 13.3 (12.1–14.4) kg at 3 months, 16.0 (14.4–17.6) kg at 6 months and 14.2 (12.1–16.3) kg at 12 months (all P < 0.001), with losses to follow‐up of 10.8%, 29.3% and 44.2%, respectively. Mean loss at 12 months by ITT analyses was: single imputation –10.5 (9.5) kg, last observation carried forward –10.9 (11.6) kg and baseline observation carried forward –7.9 (11.1) kg. The presence of diabetes had no significant impact on weight change outcomes. Conclusions: This nonsurgical approach is effective for many individuals with severe and complex obesity, representing an option before considering surgery. The results are equally effective in terms of weight loss for people with T2DM

    What do parents and preschool staff tell us about young children's physical activity: a qualitative study

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    <p>Abstract</p> <p>Background</p> <p>Physical activity and small screen recreation are two modifiable behaviours associated with childhood obesity and the development of chronic health problems. Parents and preschool staff shape behaviour habits in young children. The aims of this qualitative study were to explore the attitudes, values, knowledge and understanding of parents and carers of preschool-age children in relation to physical activity and small screen recreation and to identify influences upon these behaviours.</p> <p>Methods</p> <p>This research involved a focus group study with parents and carers of the target population. A purposive sample of 39 participants (22 parents, 17 carers) participated in 9 focus groups. Participants were drawn from three populations of interest: those from lower socioeconomic status, and Middle-Eastern and Chinese communities in the Sydney (Australia) metropolitan region.</p> <p>Results</p> <p>All participants understood the value of physical activity and the impact of excessive small screen recreation but were unfamiliar with national guidelines for these behaviours. Participants described the nature and activity patterns of young children; however, the concept of activity 'intensity' in this age group was not a meaningful term. Factors which influenced young children's physical activity behaviour included the child's personality, the physical activity facilities available, and the perceived safety of their community. Factors facilitating physical activity included a child's preference for being active, positive parent or peer modelling, access to safe play areas, organised activities, preschool programs and a sense of social connectedness. Barriers to physical activity included safety concerns exacerbated by negative media stories, time restraints, financial constraints, cultural values favouring educational achievement, and safety regulations about equipment design and use within the preschool environment. Parents considered that young children are naturally 'programmed' to be active, and that society 'de-programs' this behaviour. Staff expressed concern that free, creative active play was being lost and that alternate activities were increasingly sedentary.</p> <p>Conclusion</p> <p>The findings support the relevance of the socioecological model of behavioural influences to young children's physical activity. In this age group, efforts may best be directed at emphasising national guidelines for small screen recreation and educating families and carers about the importance of creative, free play to reinforce the child's inherent nature to be active.</p
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