Runaway modes in model field theories

Within the framework of linear quantum field theories, a general study is presented of the existence and removal of runaway modes—solutions of the equations of motion which exhibit a real exponential time dependence. It is hoped that this work will yield insight into the corresponding problem in physically realistic theories. It is shown that runaway modes occur only when the Hamiltonian is not positive definite, and that they occur in linear quantum theories whenever they appear in the corresponding classical theories. Three methods are proposed for eliminating these unphysical modes One is the analog of the method used by Dirac in classical electron theory; the other two are believed to be new

Psychosocial interventions for patients with head and neck cancer.

BACKGROUND: A diagnosis of head and neck cancer, like many other cancers, can lead to significant psychosocial distress. Patients with head and neck cancer can have very specific needs, due to both the location of their disease and the impact of treatment, which can interfere with basic day-to-day activities such as eating, speaking and breathing. There is a lack of clarity on the effectiveness of the interventions developed to address the psychosocial distress experienced by patients living with head and neck cancer. OBJECTIVES: To assess the effectiveness of psychosocial interventions to improve quality of life and psychosocial well-being for patients with head and neck cancer. SEARCH METHODS: We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 17 December 2012. SELECTION CRITERIA: We selected randomised controlled trials and quasi-randomised controlled trials of psychosocial interventions for adults with head and neck cancer. For trials to be included the psychosocial intervention had to involve a supportive relationship between a trained helper and individuals diagnosed with head and neck cancer. Outcomes had to be assessed using a validated quality of life or psychological distress measure, or both. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials, extracted data and assessed the risk of bias, with mediation from a third author where required. Where possible, we extracted outcome measures for combining in meta-analyses. We compared continuous outcomes using either mean differences (MD) or standardised mean differences (SMD) and 95% confidence intervals (CI), with a random-effects model. We conducted meta-analyses for the primary outcome measure of quality of life and secondary outcome measures of psychological distress, including anxiety and depression. We subjected the remaining outcome measures (self esteem, coping, adjustment to cancer, body image) to a narrative synthesis, due to the limited number of studies evaluating these specific outcomes and the wide divergence of assessment tools used. MAIN RESULTS: Seven trials, totaling 542 participants, met the eligibility criteria. Studies varied widely on risk of bias, interventions used and outcome measures reported. From these studies, there was no evidence to suggest that psychosocial intervention promotes global quality of life for patients with head and neck cancer at end of intervention (MD 1.23, 95% CI -5.82 to 8.27) as measured by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30). This quality of life tool includes five functional scales, namely cognitive, physical, emotional, social and role. There was no evidence to demonstrate that psychosocial intervention provides an immediate or medium-term improvement on any of these five functional scales. From the data available, there was no significant change in levels of anxiety (SMD -0.09, 95% CI -0.40 to 0.23) or depression following intervention (SMD -0.03, 95% CI -0.24 to 0.19). At present, there is insufficient evidence to refute or support the effectiveness of psychosocial intervention for patients with head and neck cancer. AUTHORS' CONCLUSIONS: The evidence for psychosocial intervention is limited by the small number of studies, methodological shortcomings such as lack of power, difficulties with comparability between types of interventions and a wide divergence in outcome measures used. Future research should be targeted at patients who screen positive for distress and use validated outcome measures, such as the EORTC scale, as a measure of quality of life. These studies should implement interventions that are theoretically derived. Other shortcomings should be addressed in future studies, including using power calculations that may encourage multi-centred collaboration to ensure adequate sample sizes are recruited

2PI effective action and gauge invariance problems

The problem of maintaining gauge invariance when truncating the two particle irreducible (2PI) effective action has been studied recently by several authors. Here we give a simple and very general derivation of the gauge dependence identities for the off-shell 2PI effective action. We consider the case where the gauge is fixed by an arbitrary function of the quantum gauge field, subject only to the restriction that the Faddeev-Popov matrix is invertable. We also study the background field gauge. We address the role that these identies play in solving gauge invariance problems associated with physical quantities calculated using a truncated on-shell 2PI effective action.Comment: 11 pages, version accepted for publication in Eur. Phys. Jour.

Mechanical properties of ZnO epitaxial layers grown on a- and c-axis sapphire

The mechanical properties of zinc oxide epitaxial layers grown on a- and c-axis sapphire have been studied by spherical nanoindentation and cross-sectional transmission electron microscopy. As-grown threading dislocations, which are characteristic of epitaxialmaterial, combined with the presence of the much harder, underlying substrate are found to have a significant effect on the mechanical behavior of ZnO epilayers as compared to bulk material. Epilayer material is found to be significantly harder than its bulk counterpart. For a-axis epilayers, analysis of load–unload data yields a hardness of 6.6±1.2GPa, and 5.75±0.8GPa for c-axis layers. We attribute this increased hardness to strain compensation via the presence of as-grown defects. These defects inhibit the slip mechanism responsible for relative softness of bulk single crystals. The absence of pop-in events from analyzed continuous-load nanoindentation data is further evidence for strain compensation by native defects within the epilayers. Large variations in the spread of collected data are indicative of inhomegenity in the epilayers.The University of Sydney, for constructive comments and support. The work at UF is partially supported by the AFOSR under Grant Nos. F49620-03-1-0370 sT.S.d and NSF DMR 0400416

Non-DMS related ferromagnetism in transition metal doped zinc oxide

We review pitfalls in recent efforts to make a conventional semiconductor, namely ZnO, ferromagnetic by means of doping with transition metal ions. Since the solubility of those elements is rather low, formation of secondary phases and the creation of defects upon low temperature processing can lead to unwanted magnetic effects. Among others, ion implantation is a method of doping, which is highly suited for the investigation of those effects. By focussing mainly on Fe, Co or Ni implanted ZnO single crystals we show that there are manifold sources for ferromagnetism in this material which can easily be confused with the formation of a ferromagnetic diluted magnetic semiconductor (DMS). We will focus on metallic as well as oxide precipitates and the difficulties of their identification.Comment: 24 pages, 22 figure

Political branding: sense of identity or identity crisis? An investigation of the transfer potential of the brand identity prism to the UK Conservative Party

Brands are strategic assets and key to achieving a competitive advantage. Brands can be seen as a heuristic device, encapsulating a series of values that enable the consumer to make quick and efficient choices. More recently, the notion of a political brand and the rhetoric of branding have been widely adopted by many political parties as they seek to differentiate themselves, and this has led to an emerging interest in the idea of the political brand. Therefore, this paper examines the UK Conservative Party brand under David Cameron’s leadership and examines the applicability of Kapferer’s brand identity prism to political branding. This paper extends and operationalises the brand identity prism into a ‘political brand identity network’ which identifies the inter-relatedness of the components of the corporate political brand and the candidate political brand. Crucial for practitioners, this model can demonstrate how the brand is presented and communicated to the electorate and serves as a useful mechanism to identify consistency within the corporate and candidate political brands

Habitat continuity and stepping-stone oceanographic distances explain population genetic connectivity of the brown alga Cystoseira amentacea

Effective predictive and management approaches for species occurring in a metapopulation structure require good understanding of interpopulation connectivity. In this study, we ask whether population genetic structure of marine species with fragmented distributions can be predicted by stepping-stone oceanographic transport and habitat continuity, using as model an ecosystem-structuring brown alga, Cystoseira amentacea var. stricta. To answer this question, we analysed the genetic structure and estimated the connectivity of populations along discontinuous rocky habitat patches in southern Italy, using microsatellite markers at multiple scales. In addition, we modelled the effect of rocky habitat continuity and ocean circulation on gene flow by simulating Lagrangian particle dispersal based on ocean surface currents allowing multigenerational stepping-stone dynamics. Populations were highly differentiated, at scales from few metres up to thousands of kilometres. The best possible model fit to explain the genetic results combined current direction, rocky habitat extension and distance along the coast among rocky sites. We conclude that a combination of variable suitable habitat and oceanographic transport is a useful predictor of genetic structure. This relationship provides insight into the mechanisms of dispersal and the role of life-history traits. Our results highlight the importance of spatially explicit modelling of stepping-stone dynamics and oceanographic directional transport coupled with habitat suitability, to better describe and predict marine population structure and differentiation. This study also suggests the appropriate spatial scales for the conservation, restoration and management of species that are increasingly affected by habitat modifications.MARES Grant (Doctoral Programme in Marine Ecosystem Health and Conservation) [EU-512002-1-2010-1-BE-EMJD]; Ghent University [FPA 2011-0016]; FCT (Portugal); project TETRIS; [SFRH/BPD/63703/2009]; [SFRH/BPD/107878/2015]; [SFRH/BPD/111003/2015]info:eu-repo/semantics/publishedVersio

Disoriented Chiral Condensate: Theory and Experiment

It is thought that a region of pseudo-vacuum, where the chiral order parameter is misaligned from its vacuum orientation in isospin space, might occasionally form in high energy hadronic or nuclear collisions. The possible detection of such disoriented chiral condensate (DCC) would provide useful information about the chiral structure of the QCD vacuum and/or the chiral phase transition of strong interactions at high temperature. We review the theoretical developments concerning the possible DCC formation in high-energy collisions as well as the various experimental searches that have been performed so far. We discuss future prospects for upcoming DCC searches, e.g. in high-energy heavy-ion collision experiments at RHIC and LHC.Comment: 120 pages, 52 figures. Uses elsart.cls. To appear in Physics Reports. Minor corrections, references adde

Using Cognitive Pre-Testing Methods in the Development of a New Evidenced-Based Pressure Ulcer Risk Assessment Instrument

Background: Variation in development methods of Pressure Ulcer Risk Assessment Instruments has led to inconsistent inclusion of risk factors and concerns about content validity. A new evidenced-based Risk Assessment Instrument, the Pressure Ulcer Risk Primary Or Secondary Evaluation Tool - PURPOSE-T was developed as part of a National Institute for Health Research (NIHR) funded Pressure Ulcer Research Programme (PURPOSE: RP-PG-0407-10056). This paper reports the pre-test phase to assess and improve PURPOSE-T acceptability, usability and confirm content validity. Methods: A descriptive study incorporating cognitive pre-testing methods and integration of service user views was undertaken over 3 cycles comprising PURPOSE-T training, a focus group and one-to-one think-aloud interviews. Clinical nurses from 2 acute and 2 community NHS Trusts, were grouped according to job role. Focus group participants used 3 vignettes to complete PURPOSE-T assessments and then participated in the focus group. Think-aloud participants were interviewed during their completion of PURPOSE-T. After each pre-test cycle analysis was undertaken and adjustment/improvements made to PURPOSE-T in an iterative process. This incorporated the use of descriptive statistics for data completeness and decision rule compliance and directed content analysis for interview and focus group data. Data were collected April 2012-June 2012. Results: Thirty-four nurses participated in 3 pre-test cycles. Data from 3 focus groups, 12 think-aloud interviews incorporating 101 PURPOSE-T assessments led to changes to improve instrument content and design, flow and format, decision support and item-specific wording. Acceptability and usability were demonstrated by improved data completion and appropriate risk pathway allocation. The pre-test also confirmed content validity with clinical nurses. Conclusions: The pre-test was an important step in the development of the preliminary PURPOSE-T and the methods used may have wider instrument development application. PURPOSE-T proposes a new approach to pressure ulcer risk assessment, incorporating a screening stage, the inclusion of skin status to distinguish between those who require primary prevention and those who require secondary prevention/treatment and the use of colour to support pathway allocation and decision making. Further clinical evaluation is planned to assess the reliability and validity of PURPOSE-T and it’s impact on care processes and patient outcomes

1939: Abilene Christian College Bible Lectures - Full Text

Delivered in the Auditorium of Abilene Christian College, February, 1939, Abilene, Texas Published October, 1939 PRICE, $1.00 FIRM FOUNDATION PUBLISHING HOUSE Austin, Texas