Description of Gluon Propagation in the Presence of an A^2 Condensate

There is a good deal of current interest in the condensate A^2 which has been seen to play an important role in calculations which make use of the operator product expansion. That development has led to the publication of a large number of papers which discuss how that condensate could play a role in a gauge-invariant formulation. In the present work we consider gluon propagation in the presence of such a condensate which we assume to be present in the vacuum. We show that the gluon propagator has no on-mass-shell pole and, therefore, a gluon cannot propagate over extended distances. That is, the gluon is a nonpropagating mode in the gluon condensate. In the present work we discuss the properties of both the Euclidean-space and Minkowski-space gluon propagator. In the case of the Euclidean-space propagator we can make contact with the results of QCD lattice calculations of the propagator in the Landau gauge. With an appropriate choice of normalization constants, we present a unified representation of the gluon propagator that describes both the Minkowski-space and Euclidean-space dynamics in which the A^2 condensate plays an important role.Comment: 28 pages, 11 figure

The Nielsen Identities for the Two-Point Functions of QED and QCD

We consider the Nielsen identities for the two-point functions of full QCD and QED in the class of Lorentz gauges. For pedagogical reasons the identities are first derived in QED to demonstrate the gauge independence of the photon self-energy, and of the electron mass shell. In QCD we derive the general identity and hence the identities for the quark, gluon and ghost propagators. The explicit contributions to the gluon and ghost identities are calculated to one-loop order, and then we show that the quark identity requires that in on-shell schemes the quark mass renormalisation must be gauge independent. Furthermore, we obtain formal solutions for the gluon self-energy and ghost propagator in terms of the gauge dependence of other, independent Green functions.Comment: 25 pages, plain TeX, 4 figures available upon request, MZ-TH/94-0

Non-verbal communication in meetings of psychiatrists and patients with schizophrenia

Objective Recent evidence found that patients with schizophrenia display non‐verbal behaviour designed to avoid social engagement during the opening moments of their meetings with psychiatrists. This study aimed to replicate, and build on, this finding, assessing the non‐verbal behaviour of patients and psychiatrists during meetings, exploring changes over time and its association with patients' symptoms and the quality of the therapeutic relationship. Method 40‐videotaped routine out‐patient consultations, involving patients with schizophrenia, were analysed. Non‐verbal behaviour of patients and psychiatrists was assessed during three fixed, 2‐min intervals using a modified Ethological Coding System for Interviews. Symptoms, satisfaction with communication and the quality of the therapeutic relationship were also measured. Results Over time, patients' non‐verbal behaviour remained stable, whilst psychiatrists' flight behaviour decreased. Patients formed two groups based on their non‐verbal profiles, one group (n = 25) displaying pro‐social behaviour, inviting interaction and a second (n = 15) displaying flight behaviour, avoiding interaction. Psychiatrists interacting with pro‐social patients displayed more pro‐social behaviours (P < 0.001). Patients' pro‐social profile was associated reduced symptom severity (P < 0.05), greater satisfaction with communication (P < 0.001) and positive therapeutic relationships (P < 0.05). Conclusion Patients' non‐verbal behaviour during routine psychiatric consultations remains unchanged, and is linked to both their psychiatrist's non‐verbal behaviour and the quality of the therapeutic relationship

Managing medical emergencies in mental health settings using an interprofessional in-situ simulation training programme: A mixed methods evaluation study

BACKGROUND: In the UK, people with severe mental illness die up to 20years earlier than the general population, prompting increased focus on physical health in mental illness. However, training for mental health inpatient staff to meet patients' physical health needs has not received the same attention, with physical health training often being reactive and lacking evidence of effectiveness. OBJECTIVES: To evaluate an interprofessional, in situ, simulation training intervention for managing medical deterioration in mental health settings. Investigating the impact of training on: 1. Participants' knowledge, confidence, and attitudes towards managing medical deterioration; and 2. Incident reporting, as an objective index of incident management. Participants' perceptions of the impact on their practice were qualitatively explored. DESIGN: This evaluation employed a mixed-methods pre-post intervention design. PARTICIPANTS & SETTINGS: Fifty-three healthcare professionals participated including: mental health nurses, psychiatrists, healthcare assistants, and activity co-ordinators from two busy psychiatric triage wards in South London, UK. METHODS: The intervention comprised eight half-day sessions delivered weekly across two wards. Structured surveys assessed participants' knowledge, confidence, and attitudes towards medical deterioration pre and post training. Participants' experience of training was qualitatively captured through post-course surveys and focus groups three months post training. Incident reporting rates for seven-month periods pre and post training were compared. RESULTS: Following training, participants showed significant improvement in knowledge (p<0.001), confidence (p<0.001), and attitudes towards (p<0.02) managing medical deterioration. Incident reporting increased by 33% following training. Participants' reported improved confidence in managing medical deterioration, better understanding of effective communication, improved self-reflection and team working, and an increased sense of responsibility for patients' physical health. CONCLUSIONS: Interprofessional, in situ simulation training for medical deterioration yielded promising outcomes for individuals and teams. Simulation is an under-used training modality in mental health, offering a holistic training approach with the potential to provide educational and clinical benefits while supporting workforce resilience

Asymptotic Dynamics in Quantum Field Theory

A crucial element of scattering theory and the LSZ reduction formula is the assumption that the coupling vanishes at large times. This is known not to hold for the theories of the Standard Model and in general such asymptotic dynamics is not well understood. We give a description of asymptotic dynamics in field theories which incorporates the important features of weak convergence and physical boundary conditions. Applications to theories with three and four point interactions are presented and the results are shown to be completely consistent with the results of perturbation theory.Comment: 18 pages, 3 figure

The factorisation of glue and mass terms in SU(N) gauge theories

In this paper we investigate the structure of the glue in Zwanziger's gauge invariant expansion for the A^2-type mass term in Yang-Mills theory. We show how to derive this expansion, in terms of the inverse covariant Laplacian, and extend it to higher orders. In particular, we give an explicit expression, for the first time, for the next to next to leading order term. We further show that the expansion is not unique and give examples of the resulting ambiguity.Comment: 22 page