145 research outputs found
The Breathing Mode in Extended Skyrme Model
We study an extended Skyrme model which includes fourth and sixth-order
terms. We explore some static properties like the -nucleon mass
splitting and investigate the Skyrmion breathing mode in the framework of the
linear response theory. We find that the monopole response function has a
pronounced peak located at 400 MeV, which we identify to the Roper
resonance . As compared to the standard one, the extended Skyrme model
provides a more accurate description of baryon properties.Comment: 12 pages of plain Latex and 3 figures (available from the authors),
preprint IPNO/TH 93-0
Effective chiral Lagrangians for spin-1 mesons
The commonly used types of effective theory for vector mesons are reviewed
and their relationships clarified. They are shown to correspond to different
choices of field for spin-1 particles and the rules for transforming between
them are described. The importance of respecting chiral symmetry is stressed.
The choice of fields that transform homogeneously under the nonlinear
realisation of chiral symmetry imposes no preconceptions about the types of
coupling for the mesons. This representation thus provides a convenient
framework for relating different theories. It is also used to elucidate the
nature of the assumptions in specific hidden-gauge and massive Yang-Mills
models that have been widely used.Comment: 46 pages (RevTeX
Infection control and the prevalence, management and outcomes of SARS-CoV-2 infections in mental health wards in London, UK: lessons learned from wave 1 to wave 2
Background:
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) has high morbidity and mortality in older adults and people with dementia. Infection control and prevention measures potentially reduce transmission within hospitals.
Aims:
We aimed to replicate our earlier study of London mental health in-patients to examine changes in clinical guidance and practice and associated COVID-19 prevalence and outcomes between COVID-19 waves 1 and 2 (1 March to 30 April 2020 and 14 December 2020 to 15 February 2021).
Method:
We collected the 2 month period prevalence of wave 2 of COVID-19 in older (≥65 years) in-patients and those with dementia, as well as patients’ characteristics, management and outcomes, including vaccinations. We compared these results with those of our wave 1 study.
Results:
Sites reported that routine testing and personal protective equipment were available, and routine patient isolation on admission occurred throughout wave 2. COVID-19 infection occurred in 91/358 (25%; 95% CI 21–30%) v. 131/344, (38%; 95% CI 33–43%) P < 0.001 in wave 1. Hospitals identified more asymptomatic carriers (26/91; 29% v. 16/130; 12%) and fewer deaths (12/91; 13% v. 19/131; 15%; odds ratio = 0.92; 0.37–1.81) compared with wave 1. The patient vaccination uptake rate was 49/58 (85%).
Conclusions:
Patients in psychiatric in-patient settings, mostly admitted without known SARS-CoV-2 infection, had a high risk of infection compared with people in the community but lower than that during wave 1. Availability of infection control measures in line with a policy of parity of esteem between mental and physical health appears to have lowered within-hospital COVID-19 infections and deaths. Cautious management of vulnerable patient groups including mental health patients may reduce the future impact of COVID-19
On different lagrangian formalisms for vector resonances within chiral perturbation theory
We study the relation of vector Proca field formalism and antisymmetric
tensor field formalism for spin-one resonances in the context of the large N_C
inspired chiral resonance Lagrangian systematically up to the order O(p6) and
give a transparent prescription for the transition from vector to antisymmetric
tensor Lagrangian and vice versa. We also discuss the possibility to describe
the spin-one resonances using an alternative "mixed" first order formalism,
which includes both types of fields simultaneously, and compare this one with
the former two. We also briefly comment on the compatibility of the above
lagrangian formalisms with the high-energy constraints for concrete VVP
correlator.Comment: 34 pages, 3 figure
Cooperative Regulation of the Activity of Factor Xa within Prothrombinase by Discrete Amino Acid Regions from Factor Va Heavy Chain†
ABSTRACT: The prothrombinase complex catalyzes the activation of prothrombin to R-thrombin. We have repetitively shown that amino acid region 695DYDY698 from the COOH terminus of the heavy chain of factor Va regulates the rate of cleavage of prothrombin at Arg271 by prothrombinase. We have also recently demonstrated that amino acid region 334DY335 is required for the optimal activity of prothrombinase. To assess the effect of these six amino acid residues on cofactor activity, we created recombinant factor Va molecules combining mutations at amino acid regions 334–335 an
Isoscalar NN spin-orbit potential from a Skyrme model with scalar mesons
As a first step toward circumventing the difficulty to obtain an attractive
isospin-independent NN spin-orbit force from Skyrme-type models involving only
pions, we investigate an improved Skyrme Lagrangian that incorporates the
scalar-isoscalar meson \epsilon which can be viewed as the cause behind the
enhancement of the -wave. We find that at large distances, the main
contribution to the spin-orbit potential comes from the scalar Lagrangian and
it is found to be attractive. We briefly discuss how to pursue this work to
finally obtain a medium-range attractive interaction.Comment: 10 pages (revtex) + 2 figures; use \psfig command. Minor changes in
the text and some discussion added in the last section. To be published in Z.
Phys.
Mild cognitive impairment: the Manchester consensus
Given considerable variation in diagnostic and therapeutic practice, there is a need for national guidance on the use of neuroimaging, fluid biomarkers, cognitive testing, follow-up and diagnostic terminology in mild cognitive impairment (MCI). MCI is a heterogenous clinical syndrome reflecting a change in cognitive function and deficits on neuropsychological testing but relatively intact activities of daily living. MCI is a risk state for further cognitive and functional decline with 5–15% of people developing dementia per year. However, ~50% remain stable at 5 years and in a minority, symptoms resolve over time. There is considerable debate about whether MCI is a useful clinical diagnosis, or whether the use of the term prevents proper inquiry (by history, examination and investigations) into underlying causes of cognitive symptoms, which can include prodromal neurodegenerative disease, other physical or psychiatric illness, or combinations thereof. Cognitive testing, neuroimaging and fluid biomarkers can improve the sensitivity and specificity of aetiological diagnosis, with growing evidence that these may also help guide prognosis. Diagnostic criteria allow for a diagnosis of Alzheimer’s disease to be made where MCI is accompanied by appropriate biomarker changes, but in practice, such biomarkers are not available in routine clinical practice in the UK. This would change if disease-modifying therapies became available and required a definitive diagnosis but would present major challenges to the National Health Service and similar health systems. Significantly increased investment would be required in training, infrastructure and provision of fluid biomarkers and neuroimaging. Statistical techniques combining markers may provide greater sensitivity and specificity than any single disease marker but their practical usefulness will depend on large-scale studies to ensure ecological validity and that multiple measures, e.g. both cognitive tests and biomarkers, are widely available for clinical use. To perform such large studies, we must increase research participation amongst those with MCI
Cleavage Requirements for Activation of Factor V by Factor Xa
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65728/1/j.1432-1033.1997.00012.x.pd
- …