3,672 research outputs found
Kink Chains from Instantons on a Torus
We describe how the procedure of calculating approximate solitons from
instanton holonomies may be extended to the case of soliton crystals. It is
shown how sine-Gordon kink chains may be obtained from CP1 instantons on a
torus. These kink chains turn out to be remarkably accurate approximations to
the true solutions. Some remarks on the relevance of this work to Skyrme
crystals are also made.Comment: latex 17 pages, DAMTP 94-7
Inversion symmetric 3-monopoles and the Atiyah-Hitchin manifold
We consider 3-monopoles symmetric under inversion symmetry. We show that the
moduli space of these monopoles is an Atiyah-Hitchin submanifold of the
3-monopole moduli space. This allows what is known about 2-monopole dynamics to
be translated into results about the dynamics of 3-monopoles. Using a numerical
ADHMN construction we compute the monopole energy density at various points on
two interesting geodesics. The first is a geodesic over the two-dimensional
rounded cone submanifold corresponding to right angle scattering and the second
is a closed geodesic for three orbiting monopoles.Comment: latex, 22 pages, 2 figures. To appear in Nonlinearit
Analysis of the relationship between disease activity and damage in patients with systemic lupus erythematosus—a 5-yr prospective study
Objective. To determine whether initial damage, disease duration, age, initial health status, average disease activity over the 5 yr or an average medication score covering the follow-up period would predict an increase in damage in patients with systemic lupus erythematosus (SLE) within the next 5 yr. Methods. A 5-yr prospective longitudinal study of a cohort of 141 consecutive patients with SLE attending a specialist lupus out-patient clinic in London from their first assessment between July 1994 and February 1995. Disease activity was assessed using the BILAG system, initial health status by the Medical Outcome Survey Short Form 20 with an extra question about fatigue (SF-20+) and damage by the SLICC/ACR Damage Index (SDI). Damage was reassessed 5 yr later. Statistical analysis was carried out using multiple logistic regression analysis (logXact). Results. One hundred and thirty-three female and eight male SLE patients (97 Caucasians, 16 Afro-Caribbeans, 22 Asians and 6 others) were included, their age at inclusion was 41.1 ± 12.5 yr and their disease duration 10.2 ± 6.3 yr. The mean measures at inclusion were: total BILAG 5.2 (range 0-17), total SDI 1.2 (0-7) and medication score 1.2 (0-3). Six patients were lost to follow-up because they had moved. Of the remaining 135 patients total damage had increased in 40 patients and 10 patients had died. At the end of the study, at 4.63 ± 0.19 yr, the total SDI had increased to 1.6 ± 1.7. Multiple logistic regression analysis revealed that death and increase in damage were strongly predicted by a high total disease activity over the entire study period (P<0.001) as we had hypothesized. When the total BILAG score was replaced by the average number of A-flares the prediction of accrual of damage during the study period was again highly significant (P = 0.004). Conclusions. In this first prospective study of its type a highly significant impact of total disease activity, as measured over 5 yr using the BILAG system, on the development of total damage was revealed. Moreover, these results provide further proof of the validity of the SDI and support the BILAG concept of the A-flare
Symmetric Instantons and Skyrme Fields
By explicit construction of the ADHM data, we prove the existence of a charge
seven instanton with icosahedral symmetry. By computing the holonomy of this
instanton we obtain a Skyrme field which approximates the minimal energy charge
seven Skyrmion. We also present a one parameter family of tetrahedrally
symmetric instantons whose holonomy gives a family of Skyrme fields which
models a Skyrmion scattering process, where seven well-separated Skyrmions
collide to form the icosahedrally symmetric Skyrmion.Comment: 22 pages plus 1 figure in GIF forma
Can remote STI/HIV testing and eClinical Care be compatible with robust public health surveillance?
In this paper we outline the current data capture systems for human immunodeficiency virus (HIV) and sexually transmitted infection (STI) surveillance used by Public Health England (PHE), and how these will be affected by the introduction of novel testing platforms and changing patient pathways. We outline the Chlamydia Online Clinical Care Pathway (COCCP), developed as part of the Electronic Self-Testing for Sexually Transmitted Infections (eSTI(2)) Consortium, which ensures that surveillance data continue to be routinely collected and transmitted to PHE. We conclude that both novel diagnostic testing platforms and established data capture systems must be adaptable to ensure continued robust public health surveillance
Patient-maintained sedation for oral surgery using a target-controlled infusion of propofol - a pilot study
OBJECTIVE: To assess the safety and efficacy of a new patient-maintained propofol system for conscious sedation in dentistry. DESIGN: Prospective clinical trial SETTING: Department of Sedation, Glasgow Dental Hospital and School, 2001 SUBJECTS AND METHODS: Patients scheduled for oral surgery with conscious sedation. Exclusions included ASA IV -V, inability to use the handset, opioid use and severe respiratory disease. INTERVENTIONS: Patients were given intravenous propofol to a level of 1.0 microg/ml (reducing from 1.5 microg/ml) using a target controlled infusion system, they then controlled their sedation level by double-clicking a handset which on each activation increased the propofol concentration by 0.2 microg/ml. MAIN OUTCOME MEASURES: Oxygen saturation, patient satisfaction, and surgeon satisfaction. RESULTS: Twenty patients were recruited, 16 female and four male. Nineteen patients completed sedation and treatment successfully. Mean lowest oxygen saturation was 94%. No patients were over-sedated. All patients successfully used the system to maintain a level of sedation adequate for their comfort. Patient and surgeon satisfaction were consistently high. CONCLUSIONS: Initial experience with this novel system has confirmed safety, patient satisfaction and surgeon satisfaction
New Integrable Sectors in Skyrme and 4-dimensional CP^n Model
The application of a weak integrability concept to the Skyrme and
models in 4 dimensions is investigated. A new integrable subsystem of the
Skyrme model, allowing also for non-holomorphic solutions, is derived. This
procedure can be applied to the massive Skyrme model, as well. Moreover, an
example of a family of chiral Lagrangians providing exact, finite energy
Skyrme-like solitons with arbitrary value of the topological charge, is given.
In the case of models a tower of integrable subsystems is obtained. In
particular, in (2+1) dimensions a one-to-one correspondence between the
standard integrable submodel and the BPS sector is proved. Additionally, it is
shown that weak integrable submodels allow also for non-BPS solutions.
Geometric as well as algebraic interpretations of the integrability conditions
are also given.Comment: 23 page
Dynamical Toroidal Hopfions in a Ferromagnet with Easy-Axis Anisotropy
Three-dimensional toroidal precession solitons with a nonzero Hopf index,
which uniformly move along the anisotropy axis in a uniaxial ferromagnet, have
been found. The structure and existence region of the solitons have been
numerically determined by solving the Landau-Lifshitz equation.Comment: 6 pages, 4 figure
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
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