2,418 research outputs found
Evaluation of a Simplified Measurement for Low Glomerular Filtration Rates With lndium-111 DTPA
A rapid new method for measuring glomerular filtration rates using 111In diethylenetriamine pentaacetic acid (111In- DTPA) was evaluated with 39 patients who showed marked impairment of renal function (creatinine clearance less than 20 ml/min). A simple, single compartment system was assumed. For comparison, parallel inulin and creatinine clearances were performed. High linear correlations (r = 0.96-0.97) were demonstrated when 111In- DTPA clearances were compared with the standard nonisotopic tests. Initial data indicate that reliable isotopic clearance values could be obtained for low clearances by withdrawing only two blood samples for assay at 6 and 48 hours after isotope injection (without urine assay)
A high-finesse Fabry-Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab
A high-finesse Fabry-Perot cavity with a frequency-doubled continuous wave
green laser (532~nm) has been built and installed in Hall A of Jefferson Lab
for high precision Compton polarimetry. The infrared (1064~nm) beam from a
ytterbium-doped fiber amplifier seeded by a Nd:YAG nonplanar ring oscillator
laser is frequency doubled in a single-pass periodically poled MgO:LiNbO
crystal. The maximum achieved green power at 5 W IR pump power is 1.74 W with a
total conversion efficiency of 34.8\%. The green beam is injected into the
optical resonant cavity and enhanced up to 3.7~kW with a corresponding
enhancement of 3800. The polarization transfer function has been measured in
order to determine the intra-cavity circular laser polarization within a
measurement uncertainty of 0.7\%. The PREx experiment at Jefferson Lab used
this system for the first time and achieved 1.0\% precision in polarization
measurements of an electron beam with energy and current of 1.0~GeV and
50~A.Comment: 20 pages, 22 figures, revised version of arXiv:1601.00251v1,
submitted to NIM
Phase diagram of a generalized Winfree model
We study the phase diagram of a generalized Winfree model. The modification
is such that the coupling depends on the fraction of synchronized oscillators,
a situation which has been noted in some experiments on coupled Josephson
junctions and mechanical systems. We let the global coupling k be a function of
the Kuramoto order parameter r through an exponent z such that z=1 corresponds
to the standard Winfree model, z<1 strengthens the coupling at low r (low
amount of synchronization) and, at z>1, the coupling is weakened for low r.
Using both analytical and numerical approaches, we find that z controls the
size of the incoherent phase region, and one may make the incoherent behavior
less typical by choosing z<1. We also find that the original Winfree model is a
rather special case, indeed the partial locked behavior disappears for z>1. At
fixed k and varying gamma, the stability boundary of the locked phase
corresponds to a transition that is continuous for z1.
This change in the nature of the transition is in accordance with a previous
study on a similarly modified Kuramoto model.Comment: 9 pages, 3 figure
Plasmonic atoms and plasmonic molecules
The proposed paradigm of plasmonic atoms and plasmonic molecules allows one
to describe and predict the strongly localized plasmonic oscillations in the
clusters of nanoparticles and some other nanostructures in uniform way.
Strongly localized plasmonic molecules near the contacting surfaces might
become the fundamental elements (by analogy with Lego bricks) for a
construction of fully integrated opto-electronic nanodevices of any complexity
and scale of integration.Comment: 30 pages, 16 figure
The Seroepidemiology of Haemophilus influenzae Type B Prior to Introduction of an Immunization Programme in Kathmandu, Nepal.
Haemophilus influenzae type b (Hib) is now recognized as an important pathogen in Asia. To evaluate disease susceptibility, and as a marker of Hib transmission before routine immunization was introduced in Kathmandu, 71 participants aged 7 months-77 years were recruited and 15 cord blood samples were collected for analysis of anti-polyribosylribitol phosphate antibody levels by enzyme-linked immunosorbent assay. Only 20% of children under 5 years old had levels considered protective (>0.15 µg/ml), rising to 83% of 15-54 year-olds. Prior to introduction of Hib vaccine in Kathmandu, the majority of young children were susceptible to disease
Mode-coupling theory for multiple-time correlation functions of tagged particle densities and dynamical filters designed for glassy systems
The theoretical framework for higher-order correlation functions involving
multiple times and multiple points in a classical, many-body system developed
by Van Zon and Schofield [Phys. Rev. E 65, 011106 (2002)] is extended here to
include tagged particle densities. Such densities have found an intriguing
application as proposed measures of dynamical heterogeneities in structural
glasses. The theoretical formalism is based upon projection operator techniques
which are used to isolate the slow time evolution of dynamical variables by
expanding the slowly-evolving component of arbitrary variables in an infinite
basis composed of the products of slow variables of the system. The resulting
formally exact mode-coupling expressions for multiple-point and multiple-time
correlation functions are made tractable by applying the so-called N-ordering
method. This theory is used to derive for moderate densities the leading mode
coupling expressions for indicators of relaxation type and domain relaxation,
which use dynamical filters that lead to multiple-time correlations of a tagged
particle density. The mode coupling expressions for higher order correlation
functions are also succesfully tested against simulations of a hard sphere
fluid at relatively low density.Comment: 15 pages, 2 figure
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