30,498 research outputs found
Delay in diabetic retinopathy screening increases the rate of detection of referable diabetic retinopathy
Aims - To assess whether there is a relationship between delay in retinopathy screening after diagnosis of Type 2 diabetes and level of retinopathy detected.
Methods - Patients were referred from 88 primary care practices to an English National Health Service diabetic eye screening programme. Data for screened patients were extracted from the primary care databases using semi-automated data collection algorithms supplemented by validation processes. The programme uses two-field mydriatic digital photographs graded by a quality assured team.
Results - Data were available for 8183 screened patients with diabetes newly diagnosed in 2005, 2006 or 2007. Only 163 with Type 1 diabetes were identified and were insufficient for analysis. Data were available for 8020 with newly diagnosed Type 2 diabetes. Of these, 3569 were screened within 6 months, 2361 between 6 and 11 months, 1058 between 12 and 17 months, 366 between 18 and 23 months, 428 between 24 and 35 months, and 238 at 3 years or more after diagnosis. There were 5416 (67.5%) graded with no retinopathy, 1629 (20.3%) with background retinopathy in one eye, 753 (9.4%) with background retinopathy in both eyes and 222 (2.8%) had referable diabetic retinopathy. There was a significant trend (P = 0.0004) relating time from diagnosis to screening detecting worsening retinopathy. Of those screened within 6 months of diagnosis, 2.3% had referable retinopathy and, 3 years or more after diagnosis, 4.2% had referable retinopathy.
Conclusions - The rate of detection of referable diabetic retinopathy is elevated in those who were not screened promptly after diagnosis of Type 2 diabetes
Economic Implications of ERISA
If the intent of the Employee Retirement Income Security Act, ERISA, was to assure that beneficiaries of insolvent pension plans receive adequate pension benefits, sharp increases in nominal rates of interest have blunted that purpose. Without an increase in these rates, the Pension Benefit Guarantee Corporation, PBGC, the insurance agency established to guarantee benefits, faced large liabilities on the terminations of pension plans. We examine the economics of pension funds and the funding of pension funds before and after the enactment of ERISA. The Act changed the economics of pension funds. The PBGC, the employer, and the employees have interests in the assets of the pension plan. The PBGC can tax corporations to pay off liabilities and to fund guaranteed benefits; employers can terminate pension plans or overfund them; employees can ask for more benefits or claim the assets in the fund. Although the PBGC insures benefits, the insurance agent forbears, not acting quickly to protect its own interests. To prevent potential huge increases in its liabilities, the PBGC could require that employers hedge the guaranteed benefits, and fund their increases in promised benefits. Given its policies, these requirements could protect the PBGC.
Relation between chiral symmetry breaking and confinement in YM-theories
Spectral sums of the Dirac-Wilson operator and their relation to the Polyakov
loop are thoroughly investigated. The approach by Gattringer is generalized to
mode sums which reconstruct the Polyakov loop locally. This opens the
possibility to study the mode sum approximation to the Polyakov loop
correlator. The approach is re-derived for the ab initio continuum formulation
of Yang-Mills theories, and the convergence of the mode sum is studied in
detail. The mode sums are then explicitly calculated for the Schwinger model
and SU(2) gauge theory in a homogeneous background field. Using SU(2) lattice
gauge theory, the IR dominated mode sums are considered and the mode sum
approximation to the static quark anti-quark potential is obtained numerically.
We find a good agreement between the mode sum approximation and the static
potential at large distances for the confinement and the high temperature
plasma phase.Comment: 17 pages, 10 figures, typos corrected, references added, final
version to appear in PR
Microscopic theory of resonant soft x-ray scattering in systems with charge order
We present a microscopic theory of resonant soft x-ray scattering (RSXS) that
accounts for the delocalized character of valence electrons. Unlike past
approaches defined in terms of form factors for atoms or clusters, we develop a
functional determinant method that allows us to treat realistic band
structures. This method builds upon earlier theoretical work in mesoscopic
physics and accounts for both excitonic effects as well as the orthogonality
catastrophe arising from interaction between the core hole and the valence band
electrons. Comparing to RSXS measurements from stripe-ordered LBCO, we show
that the two-peak structure observed near the O K edge can be understood as
arising from dynamic nesting within the canonical cuprate band structure. Our
results provide evidence for reasonably well-defined, high-energy
quasiparticlesComment: 7 pages, 2 figure
Triple Bars and Complex Central Structures in Disk Galaxies
We present an analysis of ground-based and HST images of three early-type
barred galaxies. The first, NGC 2681, may be the clearest example yet of a
galaxy with three concentric bars. The two other galaxies were previously
suggested as triple-barred. Our analysis shows that while NGC 3945 is probably
double-barred, NGC 4371 has only one bar; but both have intriguing central
structures. NGC 3945 has a large, extremely bright disk inside its primary bar,
with patchy dust lanes, a faint nuclear ring or pseudo-ring within the disk,
and an apparent secondary bar crossing the ring. NGC 4371 has a bright nuclear
ring only marginally bluer than the surrounding bulge and bar. There is no
evidence for significant dust or star formation in either of these nuclear
rings. The presence of stellar nuclear rings suggests that the centers of these
galaxies are dynamically cool and disklike.Comment: LaTeX: 6 pages, 3 figures, uses emulateapj.sty. Accepted by
Astrophysical Journal Letters. Version with full-resolution figures available
at: http://www.astro.wisc.edu/~erwin/research
Nonequilibrium electron transport using the density matrix renormalization group
We extended the Density Matrix Renormalization Group method to study the real
time dynamics of interacting one dimensional spinless Fermi systems by applying
the full time evolution operator to an initial state. As an example we describe
the propagation of a density excitation in an interacting clean system and the
transport through an interacting nano structure
Cosmological Inflation and the Quantum Measurement Problem
According to cosmological inflation, the inhomogeneities in our universe are
of quantum mechanical origin. This scenario is phenomenologically very
appealing as it solves the puzzles of the standard hot big bang model and
naturally explains why the spectrum of cosmological perturbations is almost
scale invariant. It is also an ideal playground to discuss deep questions among
which is the quantum measurement problem in a cosmological context. Although
the large squeezing of the quantum state of the perturbations and the
phenomenon of decoherence explain many aspects of the quantum to classical
transition, it remains to understand how a specific outcome can be produced in
the early universe, in the absence of any observer. The Continuous Spontaneous
Localization (CSL) approach to quantum mechanics attempts to solve the quantum
measurement question in a general context. In this framework, the wavefunction
collapse is caused by adding new non linear and stochastic terms to the
Schroedinger equation. In this paper, we apply this theory to inflation, which
amounts to solving the CSL parametric oscillator case. We choose the
wavefunction collapse to occur on an eigenstate of the Mukhanov-Sasaki variable
and discuss the corresponding modified Schroedinger equation. Then, we compute
the power spectrum of the perturbations and show that it acquires a universal
shape with two branches, one which remains scale invariant and one with nS=4, a
spectral index in obvious contradiction with the Cosmic Microwave Background
(CMB) anisotropy observations. The requirement that the non-scale invariant
part be outside the observational window puts stringent constraints on the
parameter controlling the deviations from ordinary quantum mechanics...
(Abridged).Comment: References added, minor corrections, conclusions unchange
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