4,697 research outputs found
Radiative Tail in Decay and Some Comments on Universality
The result of lowest-order perturbation theory calculations of the photon and
positron spectra in radiative pion(e2) decay are generalized to all orders of
perturbation theory using the structure-function method. An additional source
of radiative corrections to the ratio of the positron and muon channels of pion
decay, due to emission of virtual and real photons and pairs, is considered. It
depends on details of the detection of the final particles and is large enough
to be taken into account in theoretical estimates with a level of accuracy of
0.1%.Comment: 5 pages, LaTeX, some misprints are corrected, submitted to Pisma Zh.
Eksp. Teor. Fi
Managing sleep and wakefulness in a 24 hour world
This article contributes to literature on the sociology of sleep by exploring the sleeping practices and subjective sleep experiences of two social groups: shift workers and students. It draws on data, collected in the UK from 25 semi-structured interviews, to discuss the complex ways in which working patterns and social activities impact upon experiences and expectations of sleep in our wired awake world. The data show that, typically, sleep is valued and considered to be important for health, general wellbeing, appearance and physical and cognitive functioning. However, sleep time is often cut back on in favour of work demands and social activities. While shift workers described their efforts to fit in an adequate amount of sleep per 24-hour period, for students, the adoption of a flexible sleep routine was thought to be favourable for maintaining a work–social life balance. Collectively, respondents reported using a wide range of strategies, techniques, technologies and practices to encourage, overcome or delay sleep(iness) and boost, promote or enhance wakefulness/alertness at socially desirable times. The analysis demonstrates how social context impacts not only on how we come to think about sleep and understand it, but also how we manage or self-regulate our sleeping patterns
Pion Leptonic Decays and Supersymmetry
We compute supersymmetric contributions to pion leptonic (\pi_{l2}) decays in
the Minimal Supersymmetric Standard Model (MSSM). When R-parity is conserved,
the largest contributions to the ratio R_{e/\mu} = \Gamma[ \pi^+ \to e^+
\nu_e(\gamma)]/\Gamma[ \pi^+ \to \mu^+ \nu_\mu(\gamma)] arise from one-loop
(V-A)x(V-A) corrections. These contributions can be potentially as large as the
sensitivities of upcoming experiments; if measured, they would imply
significant bounds on the chargino and slepton sectors complementary to current
collider limits. We also analyze R-parity violating interactions, which may
produce a detectable deviation in R_{e/\mu} while remaining consistent with all
other precision observables.Comment: 12 pages, 11 figures; included additional electroweak constraints in
analysis, simplified abstract, ref. adde
Simulations of a micro-PET System based on Liquid Xenon
The imaging performance of a high-resolution preclinical microPET system
employing liquid xenon as the gamma ray detection medium was simulated. The
arrangement comprises a ring of detectors consisting of trapezoidal LXe time
projection ionization chambers and two arrays of large area avalanche
photodiodes for the measurement of ionization charge and scintillation light. A
key feature of the LXePET system is the ability to identify individual photon
interactions with high energy resolution and high spatial resolution in 3
dimensions and determine the correct interaction sequence using Compton
reconstruction algorithms. The simulated LXePET imaging performance was
evaluated by computing the noise equivalent count rate, the sensitivity and
point spread function for a point source, and by examining the image quality
using a micro-Derenzo phantom according to the NEMA-NU4 standard. Results of
these simulation studies included NECR peaking at 1326 kcps at 188 MBq (705
kcps at 184 MBq) for an energy window of 450 - 600 keV and a coincidence window
of 1 ns for mouse (rat) phantoms. The absolute sensitivity at the center of the
field of view was 12.6%. Radial, tangential, and axial resolutions of 22Na
point sources reconstructed with a list-mode maximum likelihood expectation
maximization algorithm were <= 0.8 mm (FWHM) throughout the field of view.
Hot-rod inserts of < 0.8 mm diameter were resolvable in the transaxial image of
a micro-Derenzo phantom. The simulations show that a liquid xenon system would
provide new capabilities for significantly enhancing PET images
Is communications a strategic activity in UK Education?
This qualitative exploratory paper investigates whether communications/public relations is regarded by opinion formers in UK education as a strategic business activity or a tactical marketing tool. It is based upon depth interviews with 16 senior managers with strategic roles in UK higher or further education, or Government bodies, conducted between June and September 2004. The findings seem to suggest that communications/PR is ideally seen by leaders as a strategic function, but that there are limitations to this vision becoming a reality. The research goes on to offer initial conclusions on some of the issues surrounding perception, resource, and implementation of strategic communications/PR in UK education, with implications for practitioners considered
Underpinning excellence in higher education – an investigation into the leadership, governance and management behaviours of high-performing academic departments
The changes in government funding alongside external pressures of increased international and national competition have meant that higher education institutions need to excel in a turbulent environment. The leadership, governance and management (LGM) of academic departments are key concerns. This study investigates the correlation between behaviours, attitudes and competencies at a department level and overall departmental performance in terms of hard data measures. The research question this paper seeks to address is: what are the LGM behaviours that are associated with high-performance in academic departments? More than 600 people across 50 academic departments in 5 UK universities were surveyed through the use of three research phases consisting of open-ended questionnaires, critical case sampled semi-structured interviews and a fixed-response survey. Synthesising the data and findings of the study revealed a thematic framework of eight broad themes that contribute to excellence in academic departments. These were in the areas of change management, research and teaching, communication, strategy and shared values, leadership, departmental culture, rewards and staffing. The behaviours associated with each of these themes were used to construct the Underpinning Excellence model
Cyprus' image—a sun and sea destination—as a detrimental factor to seasonal fluctuations. Exploration into motivational factors for holidaying in Cyprus
Cyprus is established as a summer destination. To aid the destination in developing its winter season as well, this research uses a qualitative inductive approach to explore the tourists’ current image of the island and their motivations of visiting it. The research indicates that the current image, which essentially portrays Cyprus as a sun-and-sea destination is thought to dissuade tourists from perceiving the island as a year-round destination. Nonetheless, increasing the pull factors of the destination through the development of unique special interest products can help in extending the tourism season as well as broaden its narrow image
Moving beyond the ‘language problem': developing an understanding of the intersections of health, language and immigration status in interpreter-mediated health encounters
Health systems internationally are dealing with greater diversity in patient populations. However the focus on ‘the language problem’ has meant little attention is paid to diversity within and between migrant populations; and how interpreted consultations are influenced by intersecting migratory, ethnicity and sociodemographic variables. Our analysis of the experiences of patients, health care providers and interpreters in Scotland evidences the need to move beyond language, addressing multiple hidden inequalities in health care access and provision that operate in both clinic and, especially, home-based settings. We call for a practice-evidenced research agenda promoting cultural communication across health care and home settings, acknowledging immigration status as a social determinant of health.
Sur le plan international, des systèmes de santé font face à une diversité croissante dans ses populations de patients. Cependant, l’accent sur ‘le problème de langue’ se traduit dans une manque d’attention à la diversité a l’intérieur même et entre des populations des migrants; et la façon par laquelle des variables migratoire, ethnique et sociodémographique influencent elles-mêmes des consultations interprétées. Notre analyse des expériences des patients, des professionnels fournissant de soins de santé et des interprètes offre des preuves du besoin de dépasser le problème de langue. Et en faisant cela, nous adressons des multiples inégalités, souvent cachées dans des contextes de soins de santé, dans les milieux clinique et domicile. Nous proposons un programme de recherche basé sur la pratique, qui favorise la communication culturelle dans des milieux clinique et domicile, et qui reconnait le statut d’immigration comme un déterminant social de la santé
The OPERA trial : a protocol for the process evaluation of a randomised trial of an exercise intervention for older people in residential and nursing accommodation
Background: The OPERA trial is large cluster randomised trial testing a physical activity intervention to address
depression amongst people living in nursing and residential homes for older people. A process evaluation was
commissioned alongside the trial and we report the protocol for this process evaluation. Challenges included the
cognitive and physical ability of the participants, the need to respect the privacy of all home residents, including
study non-participants, and the physical structure of the homes. Evaluation activity had to be organised around the
structured timetable of homes, leaving limited opportunities for data collection. The aims of this process evaluation
are to provide findings that will assist in the interpretation of the clinical trial results, and to inform potential
implementation of the physical activity intervention on a wider scale.
Methods/design: Quantitative data on recruitment of homes and individuals is being collected. For homes in the
intervention arm, data on dose and fidelity of the intervention delivered; including individual rates of participation
in exercise classes are collected. In the control homes, uptake and delivery of depression awareness training is
monitored. These data will be combined with qualitative data from an in-depth study of a purposive sample of
eight homes (six intervention and two control).
Discussion: Although process evaluations are increasingly funded alongside trials, it is still rare to see the findings
published, and even rarer to see the protocol for such an evaluation published. Process evaluations have the
potential to assist in interpreting and understanding trial results as well as informing future roll-outs of
interventions. If such evaluations are funded they should also be reported and reviewed in a similar way to the
trial outcome evaluation
Global communication part 1: the use of apparel CAD technology
Trends needed for improved communication systems, through the development of future computer-aided design technology (CAD) applications, is a theme that has received attention due to its perceived benefits in improving global supply chain efficiencies. This article discusses the developments of both 2D and 3D computer-aided design capabilities, found within global fashion supply chain relationships and environments. Major characteristics identified within the data suggest that CAD/CAM technology appears to be improving; however, evidence also suggest a plateau effect, which is accrediting forced profits towards information technology manufactures, and arguably compromising the industry's competitive advantage. Nevertheless, 2D CAD increases communication speed; whereas 3D human interaction technology is seen to be evolving slowly and questionably with limited success. The article discusses the findings and also presents the issues regarding human interaction; technology education; and individual communication enhancements using technology processes. These are still prevalent topics for the future developments of global strategy and cultural communication amalgamation
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