4,214 research outputs found
Gamma and neutron dose measurements for a thermal tungsten nuclear rocket critical experiment
Measurements of gamma and neutron dose distributions in core of thermal tungsten nuclear rocket experimen
Healthcare Staffs’ Experiences and Perceptions of Caring for People with Dementia in the Acute Setting: Qualitative Evidence Synthesis
Background
Dementia is a global issue, with increasing prevalence rates impacting on health services internationally. People with dementia are frequently admitted to hospital, an environment that may not be suited to their needs. While many initiatives have been developed to improve their care in the acute setting, there is a lack of cohesive understanding of how staff experience and perceive the care they give to people with dementia in the acute setting.
Objectives
The aim of this qualitative synthesis was to explore health care staffs’ experiences and perceptions of caring for people with dementia in the acute setting. Qualitative synthesis can bring together isolated findings in a meaningful way that can inform policy development.
Settings
A screening process, using inclusion/exclusion criteria, identified qualitative studies that focused on health care staff caring for people with dementia in acute settings.
Participants
Twelve reports of nine studies were included for synthesis. Data extraction was conducted on each report by two researchers.
Methods
Framework synthesis was employed using VIPS framework, using Values, Individualised, Perspective and Social and psychological as concepts to guide synthesis. The VIPS framework has previously been used for exploring approaches to caring for people with dementia. Quality appraisal was conducted using Critical Appraisal Skills Programme (CASP) and NVivo facilitated sensitivity analysis to ensure confidence in the findings.
Results
Key themes, derived from VIPS, included a number of specific subthemes that examined: infrastructure and care pathways, person-centred approaches to care, how the person interacts with their environment and other patients, and family involvement in care decisions. The synthesis identified barriers to appropriate care for the person with dementia. These include ineffective pathways of care, unsuitable environments, inadequate resources and staffing levels and lack of emphasis on education and training for staff caring for people with dementia.
Conclusions
This review has identified key issues in the care of people with dementia in the acute setting: improving pathways of care, creating suitable environments, addressing resources and staffing levels and placing emphasis on the education for staff caring for people with dementia. Recommendations are made for practice consideration, policy development and future research. Leadership is required to instil the values needed to care for this client group in an effective and personcentred way. Qualitative evidence synthesis can inform policy and in this case, recommends VIPS as a suitable framework for guiding decisions around care for people with dementia in acute settings
Symmetric Skyrmions
We present candidates for the global minimum energy solitons of charge one to
nine in the Skyrme model, generated using sophisticated numerical algorithms.
Assuming the Skyrme model accurately represents the low energy limit of QCD,
these configurations correspond to the classical nuclear ground states of the
light elements. The solitons found are particularly symmetric, for example, the
charge seven skyrmion has icosahedral symmetry, and the shapes are shown to fit
a remarkable sequence defined by a geometric energy minimization (GEM) rule. We
also calculate the energies and sizes to within at least a few percent
accuracy. These calculations provide the basis for a future investigation of
the low energy vibrational modes of skyrmions and hence the possibility of
testing the Skyrme model against experiment.Comment: latex, 9 pages, 1 figure (fig1.gif
Characterisation of the effects of salicylidene acylhydrazide compounds on type three secretion in Escherichia coli O157:H7
Recent work has highlighted a number of compounds that target bacterial virulence by affecting gene regulation. In this work, we show that small-molecule inhibitors affect the expression of the type III secretion system (T3SS) of <i>Escherichia coli</i> O157:H7 in liquid culture and when the bacteria are attached to bovine epithelial cells. The inhibition of T3SS expression resulted in a reduction in the capacity of the bacteria to form attaching and effacing lesions. Our results show a marked variation in the ability of four structurally-related compounds to inhibit the T3SS of a panel of isolates. Using transcriptomics, we provide a comprehensive analysis of the conserved- and inhibitor-specific transcriptional responses to the four compounds. These analyses of gene expression show that numerous virulence genes, located on horizontally-acquired DNA elements, are affected by the compounds but the number of genes significantly affected varied markedly between the compounds. Overall, we highlight the importance of assessing the effect of such "anti-virulence" agents on a range of isolates and discuss the possible mechanisms which may lead to the co-ordinate down-regulation of horizontally acquired virulence genes
Skyrmions, Spectral Flow and Parity Doubles
It is well-known that the winding number of the Skyrmion can be identified as
the baryon number. We show in this paper that this result can also be
established using the Atiyah-Singer index theorem and spectral flow arguments.
We argue that this proof suggests that there are light quarks moving in the
field of the Skyrmion. We then show that if these light degrees of freedom are
averaged out, the low energy excitations of the Skyrmion are in fact spinorial.
A natural consequence of our approach is the prediction of a state
and its excitations in addition to the nucleon and delta. Using the recent
numerical evidence for the existence of Skyrmions with discrete spatial
symmetries, we further suggest that the the low energy spectrum of many light
nuclei may possess a parity doublet structure arising from a subtle topological
interaction between the slow Skyrmion and the fast quarks. We also present
tentative experimental evidence supporting our arguments.Comment: 22 pages, LaTex. Uses amstex, amssym
Surface Stress, Morphological Development, and Dislocation Nucleation During SixGe1-x Epitaxy
Utilizing Ge marker layer experiments combined with atomic number contrast (Z-contrast) imaging, we have studied the evolving surface morphology of SixGe1-x alloys during growth by molecular beam epitaxy. The marker layers map out the instability transition between planar two-dimensional (2D) growth and three-dimensional (3D) growth. The transition occurs via the gradual formation of a surface ripple as anticipated from instability theory. However, these undulations rapidly develop into crack-like surface instabilities which we simulate and explain by the mechanism of stress-driven surface diffusion. Finally, we model the large stresses associated with these features within a fracture mechanics formalism. This analysis demonstrates that crack-like instabilities provide ideal candidate sites for the nucleation of misfit dislocations
Interchain coherence of coupled Luttinger liquids at all orders in perturbation theory
We analyze the problem of Luttinger liquids coupled via a single-particle
hopping \tp and introduce a systematic diagrammatic expansion in powers of
\tp. An analysis of the scaling of the diagrams at each order allows us to
determine the power-law behavior versus \tp of the interchain hopping and of
the Fermi surface warp. In particular, for strong interactions, we find that
the exponents are dominated by higher-order diagrams producing an enhanced
coherence and a failure of linear-response theory. Our results are valid at any
finite order in \tp for the self-energy.Comment: 4 pages, 3 ps figures. Accepted for publication in Phys. Rev. Let
Bosonization of interacting fermions in arbitrary dimension beyond the Gaussian approximation
We use our recently developed functional bosonization approach to bosonize
interacting fermions in arbitrary dimension beyond the Gaussian
approximation. Even in the finite curvature of the energy dispersion at
the Fermi surface gives rise to interactions between the bosons. In higher
dimensions scattering processes describing momentum transfer between different
patches on the Fermi surface (around-the-corner processes) are an additional
source for corrections to the Gaussian approximation. We derive an explicit
expression for the leading correction to the bosonized Hamiltonian and the
irreducible self-energy of the bosonic propagator that takes the finite
curvature as well as around-the-corner processes into account. In the special
case that around-the-corner scattering is negligible, we show that the
self-energy correction to the Gaussian propagator is negligible if the
dimensionless quantities are
small compared with unity for all patches . Here is the cutoff
of the interaction in wave-vector space, is the Fermi wave-vector,
is the chemical potential, is the usual dimensionless Landau
interaction-parameter, and is the {\it{local}} density of
states associated with patch . We also show that the well known
cancellation between vertex- and self-energy corrections in one-dimensional
systems, which is responsible for the fact that the random-phase approximation
for the density-density correlation function is exact in , exists also in
, provided (1) the interaction cutoff is small compared with
, and (2) the energy dispersion is locally linearized at the Fermi the
Fermi surface. Finally, we suggest a new systematic method to calculate
corrections to the RPA, which is based on the perturbative calculation of the
irreducible bosonic self-energy arising from the non-Gaussian terms of the
bosonized Hamiltonian.Comment: The abstract has been rewritten. No major changes in the text
Unravelling the macro-evolutionary ecology of fish–jellyfish associations: life in the ‘gingerbread house’
Fish–jellyfish interactions are important factors contributing to fish stock success. Jellyfish can compete with fish for food resources, or feed on fish eggs and larvae, which works to reduce survivorship and recruitment of fish species. However, jellyfish also provide habitat and space for developing larval and juvenile fish which use their hosts as means of protection from predators and feeding opportunities, helping to reduce fish mortality and increase recruitment. Yet, relatively little is known about the evolutionary dynamics and drivers of such associations which would allow for their more effective incorporation into ecosystem models. Here, we found that jellyfish association is a probable adaptive anti-predator strategy for juvenile fish, more likely to evolve in benthic (fish living on the sea floor), benthopelagic (fish living just above the bottom of the seafloor), and reef-associating species than those adapted to other marine habitats. We also found that jellyfish association likely preceded the evolution of a benthic, benthopelagic, and reef-associating lifestyle rather than its evolutionary consequence, as we originally hypothesized. Considering over two-thirds of the associating fish identified here are of economic importance, and the wide-scale occurrence and diversity of species involved, it is clear the formation of fish–jellyfish associations is an important but complex process in relation to the success of fish stocks globally
Theory of many-fermion systems II: The case of Coulomb interactions
In a recent paper (cond-mat/9703164) a general field-theoretical description
of many-fermion systems with short-ranged interactions has been developed. Here
we extend this theory to the case of disordered electrons interacting via a
Coulomb potential. A detailed discussion is given of the Ward identity that
controls the soft modes in the system, and the generalized nonlinear sigma
model for the Coulombic case is derived and discussed.Comment: 12 pp., REVTeX, no figs, final version as publishe
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