20,949 research outputs found
The SQCD vacuum coupled to supergravity and string theory moduli
We calculate the scalar potential of supersymmetric QCD (in the regime N_f <
N_c) coupled to N=1 supergravity with moduli-dependent gauge kinetic function
and masses. The gauge dynamics are described by the
Taylor-Veneziano-Yankielowicz superpotential for composite effective fields.
The potential can be expanded about the ``truncated'' point in the gaugino and
matter condensate directions in order to find corrections to the globally
supersymmetric minimum. The results are relevant to the phenomenology of
supersymmetry-breaking in string-inspired supergravity models, and also to
recent work on domain walls in SQCD.Comment: 13 pages, 3 eps figures. Minor typos and layout change
Fundamental constants and their variability in theories of High Energy Physics
The Standard Model of particle physics and the theory of General Relativity
(GR) currently provide a good description of almost all phenomena of particle
physics and gravitation that have received controlled experimental tests.
However, the Standard Model contains many a priori variable parameters whose
values, and whose apparent (near-)constancy, have yet to receive a convincing
theoretical explanation. At the same time, GR may now require to be extended or
altered at the largest length scales, to account for the recent apparent
accelerated cosmological expansion. In this introductory review I present
theoretical aspects of the search for explanations of the values and possible
variations of fundamental ``constants'', focusing on the possibility of
unification of interactions. I also relate cosmological variations to
modifications of gravity both locally and cosmologically.Comment: 17 pages pdflatex, proceedings of introductory lecture for ACFC
Seminar, Bad Honnef 2007, to be published in EPJ Special Topic
On the modular invariance of mass eigenstates and CP violation
We investigate the modular transformation properties of observable (light)
fields in heterotic orbifolds, in the light of recent calculations of
CP-violating quantities. Measurable quantities must be modular invariant
functions of string moduli, even if the light fields are noninvariant. We show
that physical invariance may arise by patching smooth functions that are
separately noninvariant. CP violation for on the unit circle, which
requires light and heavy states to mix under transformation, is allowed in
principle, although the Jarlskog parameter J_CP(T) must be amended relative to
previous results. However, a toy model of modular invariant mass terms
indicates that the assumption underlying these results is unrealistic. In
general the mass eigenstate basis is manifestly modular invariant and coupling
constants are smooth invariant functions of T, thus CP is unbroken on the unit
circle. We also discuss the status of CP-odd quantities when CP is a discrete
gauge symmetry, and point out a link with baryogenesis.Comment: 18 pages JHEP style, 1 fig., amssymb, amsmath, graphicx. As publishe
Modular symmetry, twisted sectors and flavour
We investigate the implications for fermion mass models in heterotic
orbifolds of the modular symmetry mixing twisted states localized at different
fixed points. We show that, unlike in the case of continuous gauge symmetries,
the mass eigenstates do not mix under the symmetry; thus coupling constants in
the low-energy theory are invariant functions of the moduli.Comment: 4 pages, ws-procs9x6.cls included. Contribution to conference
proceedings, String Phenomenology '02, Oxfor
What is the impact of 12-hour shifts on midwives' emotional wellbeing and ability to safely deliver care?
Work-related stress and burnout are not uncommon within the midwifery workforce in the UK. The reasons for this are likely to be multifactorial, but organisational issues, like insufficient staffing, 12-hour shifts and dissatisfaction with the quality of care provided are all thought to contribute. Staff within maternity services influence the safety, effectiveness and quality of care a woman, her baby and family receive yet if a midwife’s overall wellbeing is significantly affected by stress and low morale, it can have a detrimental impact on the delivery of that care. Despite this, there is currently a lack of research on how organisational issues in midwifery settings might contribute to work-related stress or burnout. 12-hour shifts are thought to have a negative impact on wellbeing, performance and delivery of care, yet the evidence remains conflicting. This study employs a quantitative methodology using a non-experimental design through the use of surveys to explore and analyse the impact of shift length and working practices on midwives’ emotional wellbeing and ability to safely deliver care. Cognitive interviewing techniques will be used to pre-test the second survey to promote the validity and reliability of results. Descriptive and inferential statistics will be used in the analyses, with control of confounding variables.Peer reviewe
In the line of duty: the emotional wellbeing of midwives
The culture and working practices within midwifery settings are key modifiable factors that influence the emotional wellbeing of midwives. As a caring profession, a culture of self-sacrifice still appears to be expected in the provision of care, despite this having a negative effect on care provision. Shift patterns, long shifts and working practices where midwives continue to miss rest breaks, work unpaid beyond their contracted hours or present for work when unwell, all have a negative impact on emotional wellbeing. Future wellbeing strategies in midwifery settings should focus on supporting a positive workplace culture that cares equally for its midwives as it does for the women and babies in its care.Peer reviewe
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