177 research outputs found
Coupling the Deconfining and Chiral Transitions
The Polyakov loop and the chiral condensate are used as order parameters to
explore analytically the possible phase structure of finite temperature QCD.
Nambu-Jona-Lasinio models in a background temporal gauge field are combined
with a Polyakov loop potential in a form suitable for both the lattice and the
continuum. Three possible behaviors are found: a first-order transition, a
second-order transition, and a region with both transitions.Comment: 4 pages, LaTeX, 4 Postscript Figures, uuencoded, Contribution to
Lattice 95 Conference Proceeding
Landau-Ginsberg Theory of Quark Confinement
We describe the SU(3) deconfinement transition using Landau-Ginsberg theory.
Drawing on perturbation theory and symmetry principles, we construct the free
energy as a function of temperature and the Polyakov loop. Once the two
adjustable parameters of the model are fixed, the pressure p, energy epsilon
and Polyakov loop expectation value P_F are calculable functions of
temperature. An excellent fit to the continuum extrapolation of lattice
thermodynamics data can be achieved. In an extended form of the model, the
glueball potential is responsible for breaking scale invariance at low
temperatures. Three parameters are required, but the glueball mass and the
gluon condensate are calculable functions of temperature, along with p, epsilon
and P_F.Comment: Lattice99(Finite Temperature and Density) <= added keywords only
change in revised version, sorry; 3 pages, LaTeX with espcrc2.sty and
epsf.tex. Talk presented at Lattice99, Pisa, 29 June - 3 July 1999, to appear
in Nucl. Phys. B (Proc.Suppl.
Seventy years of sex education in Health Education Journal: a critical review
This paper examines key debates and perspectives on sex education in Health Education Journal (HEJ), from the date of the journalâs first publication in March 1943 to the present day. Matters relating to sexuality and sexual health are revealed to be integral to HEJâs history. First published as Health and Empire (1921 â 1942), a key purpose of the journal since its inception has been to share information on venereal disease and its prevention within the UK and across the former British Empire. From 1943 to the present day, discussions on sex education in the newly-christened HEJ both reflect and respond to evolving socio-cultural attitudes towards sexuality in the UK. Changing definitions of sex education across the decades are examined, from the prevention of venereal disease and moral decline in war-time Britain in the 1940s, to a range of responses to sexual liberation in the 1960s and 1970s; from a focus on preventing sexually-transmitted infections, teenage pregnancy and HIV in the 1980s, to the provision of sexual health services alongside sex education in the 2000s. Over the past 70 years, a shift from prevention of pre-marital sexual activity to the management of its outcomes is apparent; however, while these changes over time are notable, perhaps the most striking findings of this review are the continuities in arguments for and against the discussion of sexual issues. After more than 70 years of debate, it would seem that there is little consensus concerning motivations for and the content of sex education
Static examination of the range of ankle joint dorsiflexion is not related to dynamic foot kinematics
Optics of cone photoreceptors in the chicken (Gallus gallus domesticus)
Vision is the primary sensory modality of birds, and its importance is evident in the sophistication of their visual systems. Coloured oil droplets in the cone photoreceptors represent an adaptation in the avian retina, acting as long-pass colour filters. However, we currently lack understanding of how the optical properties and morphology of component structures (e.g. oil droplet, mitochondrial ellipsoid and outer segment) of the cone photoreceptor influence the transmission of light into the outer segment and the ultimate effect they have on receptor sensitivity. In this study, we use data from microspectrophotometry, digital holographic microscopy and electron microscopy to inform electromagnetic models of avian cone photoreceptors to quantitatively investigate the integrated optical function of the cell. We find that pigmented oil droplets primarily function as spectral filters, not light collection devices, although the mitochondrial ellipsoid improves optical coupling between the inner segment and oil droplet. In contrast, unpigmented droplets found in violet-sensitive cones double sensitivity at its peak relative to other cone types. Oil droplets and ellipsoids both narrow the angular sensitivity of single cone photoreceptors, but not as strongly as those in human cones
Gravitational wave amplification of seed magnetic fields
We discuss how gravitational waves could amplify seed magnetic fields to
strengths capable of supporting the galactic dynamo. We consider the
interaction of a weak magnetic field with gravity wave distortions in almost
FRW cosmologies and find that the magnitude of the original field is amplified
proportionally to the wave induced shear anisotropy and, crucially,
proportionally to the square of the field's initial scale. The latter makes our
mechanism particularly efficient when operating on superhorizon sized magnetic
fields, like those produced during inflation. In that case, the achieved
amplification can easily boost magnetic strengths, which may still lie
relatively close to the galactic dynamo lower limits, well within the currently
accepted range.Comment: Revised version, to appear in Phys. Lett.
Junior doctor psychiatry placements in hospital and community settings : a phenomenological study
OBJECTIVES: The proportion of junior doctors required to complete psychiatry placements in the UK has increased, due in part to vacant training posts and psychiatry career workforce shortages, as can be seen across the world. The aim of this study was to understand the lived experience of a Foundation Year 1 junior doctor psychiatry placement and to understand how job components influence attitudes. DESIGN: The study was conducted using a cross-sectional qualitative phenomenological approach. SETTING: Hospital and community psychiatry department settings in the North East of England, UK. PARTICIPANTS: In total, 14 Foundation Year 1 junior doctors were interviewed including seven men and seven women aged between 23 and 34 years. The majority had completed their medical degree in the UK and were White British. RESULTS: The lived experience of a junior doctor psychiatry placement was understood by three core themes: exposure to patient recovery, connectedness with others in the healthcare team and subjective interpretations of psychiatry. The experiences were moderated by instances of role definition, reaction to the specialty and the organisational fit of the junior doctor capacity in the specialty. CONCLUSIONS: The study reinforces and adds to the literature by identifying connectedness as being important for both job satisfaction and morale, which is currently damaged within the junior doctor population. The study provides in-depth insights into the lived experience of psychiatry placements and can be taken forward by educationalists to ensure the placements are meaningful experiences for junior doctors by developing role definition, belonging, structure and psychiatric care responsibility
Nonequilibrium Quantum-Field Dynamics and Off-Shell Transport for -theory in 2+1 dimensions
We solve the Kadanoff-Baym equations for nonequilibrium initial
configurations of the -theory in 2+1 dimensions and compare to explicit
solutions of generalized transport equations for the same theory. The latter
transport equations are derived from the Kadanoff-Baym equation in a first
order gradient expansion in phase space and explicitly retain the off-shell
dynamics as inherent in the time-dependent spectral functions. The solutions of
these equations compare very well with the exact solutions of the full
Kadanoff-Baym equations with respect to the occupation numbers of the
individual modes, the spectral evolution as well as the chemical equilibration
process. Furthermore, the proper equilibrium off-shell distribution is reached
for large times contrary to the quasiparticle Boltzmann limit. We additionally
present a direct comparison of the solution of the generalized transport
equations in the Kadanoff-Baym and Botermans-Malfliet form; both solutions are
found to agree very well with each other.Comment: 43 pages, LaTex, including 15 postscript figures, submitted to Nucl.
Phys.
Cost-Effective Use of Silver Dressings for the Treatment of Hard-to-Heal Chronic Venous Leg Ulcers
Aim
To estimate the cost-effectiveness of silver dressings using a health economic model based on time-to-wound-healing in hard-to-heal chronic venous leg ulcers (VLUs).
Background
Chronic venous ulceration affects 1â3% of the adult population and typically has a protracted course of healing, resulting in considerable costs to the healthcare system. The pathogenesis of VLUs includes excessive and prolonged inflammation which is often related to critical colonisation and early infection. The use of silver dressings to control this bioburden and improve wound healing rates remains controversial.
Methods
A decision tree was constructed to evaluate the cost-effectiveness of treatment with silver compared with non-silver dressings for four weeks in a primary care setting. The outcomes: âHealed ulcerâ, âHealing ulcerâ or âNo improvementâ were developed, reflecting the relative reduction in ulcer area from baseline to four weeks of treatment. A data set from a recent meta-analysis, based on four RCTs, was applied to the model.
Results
Treatment with silver dressings for an initial four weeks was found to give a total cost saving (ÂŁ141.57) compared with treatment with non-silver dressings. In addition, patients treated with silver dressings had a faster wound closure compared with those who had been treated with non-silver dressings.
Conclusion
The use of silver dressings improves healing time and can lead to overall cost savings. These results can be used to guide healthcare decision makers in evaluating the economic aspects of treatment with silver dressings in hard-to-heal chronic VLUs
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