647 research outputs found
Enzyme-linked immunosorbent assay for urinary albumin at low concentrations
We describe an enzyme-linked immunosorbent assay (ELISA) for urinary albumin. It requires only commercially available reagents, can detect as little as 16 micrograms of albumin per liter, and analytical recovery ranges from 92 to 116%. The assay is simple, rapid, and inexpensive. Albumin excretion was 6.2 (SD 4.1) mg/24 h in healthy subjects (n = 40), 14.7 (SD 7.2) mg/24 h in albumin-test-strip-negative Type I diabetics (n = 11), and 19.7 (SD 16.2) mg/24 h in patients with essential hypertension (n = 12)
A New Perspective on Families that Receive Temporary Assistance for Needy Families (TANF)
A review of the scholarly literature shows that a number of analyses of welfare are mistakenly based upon the premise that the overwhelming majority of welfare recipients receive benefits because they are young single women who are undereducated and caring for a child either born out of wedlock or abandoned by divorce/separation. The term welfare can encompasses a number of social programs (e.g. Food Stamps, state general assistance programs, Medicaid), but in this paper it refers specifically to Aid to Families with Dependent Children (AFDC) or its contemporary Temporary Assistance for Needy Families (TANF). In an attempt to calibrate the accuracy of this long held stereotype, the authors surveyed a representative stratified random sample of individuals who received TANF in the state of Georgia. The resulting profile led to the identification of four distinctive groups on the welfare rolls. These groups or groupings, as they are referred to in the paper, show that only some families fit the traditional stereotype while others are accessing the welfare system because of health problems, child abandonment, limited retirement assets, poor education, and fluctuating labor markets
Undulation Instability of Epithelial Tissues
Treating the epithelium as an incompressible fluid adjacent to a viscoelastic
stroma, we find a novel hydrodynamic instability that leads to the formation of
protrusions of the epithelium into the stroma. This instability is a candidate
for epithelial fingering observed in vivo. It occurs for sufficiently large
viscosity, cell-division rate and thickness of the dividing region in the
epithelium. Our work provides physical insight into a potential mechanism by
which interfaces between epithelia and stromas undulate, and potentially by
which tissue dysplasia leads to cancerous invasion.Comment: 4 pages, 3 figure
Accelerating Cosmic Microwave Background map-making procedure through preconditioning
Estimation of the sky signal from sequences of time ordered data is one of
the key steps in Cosmic Microwave Background (CMB) data analysis, commonly
referred to as the map-making problem. Some of the most popular and general
methods proposed for this problem involve solving generalised least squares
(GLS) equations with non-diagonal noise weights given by a block-diagonal
matrix with Toeplitz blocks. In this work we study new map-making solvers
potentially suitable for applications to the largest anticipated data sets.
They are based on iterative conjugate gradient (CG) approaches enhanced with
novel, parallel, two-level preconditioners. We apply the proposed solvers to
examples of simulated non-polarised and polarised CMB observations, and a set
of idealised scanning strategies with sky coverage ranging from nearly a full
sky down to small sky patches. We discuss in detail their implementation for
massively parallel computational platforms and their performance for a broad
range of parameters characterising the simulated data sets. We find that our
best new solver can outperform carefully-optimised standard solvers used today
by a factor of as much as 5 in terms of the convergence rate and a factor of up
to in terms of the time to solution, and to do so without significantly
increasing the memory consumption and the volume of inter-processor
communication. The performance of the new algorithms is also found to be more
stable and robust, and less dependent on specific characteristics of the
analysed data set. We therefore conclude that the proposed approaches are well
suited to address successfully challenges posed by new and forthcoming CMB data
sets.Comment: 19 pages // Final version submitted to A&
Coherent motion of stereocilia assures the concerted gating of hair-cell transduction channels
The hair cell's mechanoreceptive organelle, the hair bundle, is highly
sensitive because its transduction channels open over a very narrow range of
displacements. The synchronous gating of transduction channels also underlies
the active hair-bundle motility that amplifies and tunes responsiveness. The
extent to which the gating of independent transduction channels is coordinated
depends on how tightly individual stereocilia are constrained to move as a
unit. Using dual-beam interferometry in the bullfrog's sacculus, we found that
thermal movements of stereocilia located as far apart as a bundle's opposite
edges display high coherence and negligible phase lag. Because the mechanical
degrees of freedom of stereocilia are strongly constrained, a force applied
anywhere in the hair bundle deflects the structure as a unit. This feature
assures the concerted gating of transduction channels that maximizes the
sensitivity of mechanoelectrical transduction and enhances the hair bundle's
capacity to amplify its inputs.Comment: 24 pages, including 6 figures, published in 200
Universal critical behavior of noisy coupled oscillators: A renormalization group study
We show that the synchronization transition of a large number of noisy
coupled oscillators is an example for a dynamic critical point far from
thermodynamic equilibrium. The universal behaviors of such critical
oscillators, arranged on a lattice in a -dimensional space and coupled by
nearest neighbors interactions, can be studied using field theoretical methods.
The field theory associated with the critical point of a homogeneous
oscillatory instability (or Hopf bifurcation of coupled oscillators) is the
complex Ginzburg-Landau equation with additive noise. We perform a perturbative
renormalization group (RG) study in a dimensional space. We
develop an RG scheme that eliminates the phase and frequency of the
oscillations using a scale-dependent oscillating reference frame. Within a
Callan-Symanzik RG scheme to two-loop order in perturbation theory, we find
that the RG fixed point is formally related to the one of the model
dynamics of the real Ginzburg-Landau theory with an O(2) symmetry of the order
parameter. Therefore, the dominant critical exponents for coupled oscillators
are the same as for this equilibrium field theory. This formal connection with
an equilibrium critical point imposes a relation between the correlation and
response functions of coupled oscillators in the critical regime. Since the
system operates far from thermodynamic equilibrium, a strong violation of the
fluctuation-dissipation relation occurs and is characterized by a universal
divergence of an effective temperature. The formal relation between critical
oscillators and equilibrium critical points suggests that long-range phase
order exists in critical oscillators above two dimensions.Comment: 24 pages, published in 200
Influence of strenuous exercise on albumin excretion
Renal albumin excretion rate was 7.3 mg/24 h (SEM 0.5, range 0.6-21.0) in 66 healthy subjects. This rate increased markedly during and shortly after strenuous exercise on a bicycle ergometer (before: 5.5 +/- 0.6 micrograms/min; during and just after: 16.9 +/- 2.2 micrograms/min; P less than 0.001; n = 30). However, albumin excretion/24 h was not significantly higher during 24 h with a period of strenuous exercise than during 24 h without such exercise (10.3 +/- 0.9 mg/24 h vs 8.5 +/- 0.7 mg/24 h)
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Experimental Transport Benchmarks for Physical Dosimetry to Support Development of Fast-Neutron Therapy with Neutron Capture Augmentation
The Idaho National Laboratory (INL), the University of Washington (UW) Neutron Therapy Center, the University of Essen (Germany) Neutron Therapy Clinic, and the Northern Illinois University(NIU) Institute for Neutron Therapy at Fermilab have been collaborating in the development of fast-neutron therapy (FNT) with concurrent neutron capture (NCT) augmentation [1,2]. As part of this effort, we have conducted measurements to produce suitable benchmark data as an aid in validation of advanced three-dimensional treatment planning methodologies required for successful administration of FNT/NCT. Free-beam spectral measurements as well as phantom measurements with Lucite{trademark} cylinders using thermal, resonance, and threshold activation foil techniques have now been completed at all three clinical accelerator facilities. The same protocol was used for all measurements to facilitate intercomparison of data. The results will be useful for further detailed characterization of the neutron beams of interest as well as for validation of various charged particle and neutron transport codes and methodologies for FNT/NCT computational dosimetry, such as MCNP [3], LAHET [4], and MINERVA [5]
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