3,809 research outputs found
Accurate theoretical fits to laser ARPES EDCs in the normal phase of cuprate superconductors
Anderson has recently proposed a theory of the strange metal state above Tc
in the high Tc superconductors. [arXiv:cond-mat/0512471] It is based on the
idea that the unusual transport properties and spectral functions are caused by
the strong Mott- Hubbard interactions and can be computed by using the formal
apparatus of Gutzwiller projection. In ref. 1 Anderson computed only the
tunneling spectrum and the power-law exponent of the infrared conductivity. He
had calculated the energy distribution curves (EDCs) in angle resolved
photoemission spectroscopy (ARPES) but was discouraged when these differed
radically from the best ARPES measurements available at the time, and did not
include them. In this letter we compare the spectral functions computed within
this model to the novel laser-ARPES data of the Dessau group.These are found to
capture the shape of the experimental EDCs with unprecedented accuracy and in
principle have only one free parameter
THE EFFECT OF ROUNDING ON THE PROBABILITY DISTRIBUTION OF REGRADING IN THE U.S. PEANUT INDUSTRY
This article determines the effect of rounding (pointing-off) of grade percentages to the nearest whole number on the probability distribution of regrading in the peanut industry. Results show that rounding causes graders to have to regrade an extra 4% of samples even when they follow all directions and make no mistakes. When rounding was not used, the sample weight had little effect on the probability of regrading. With rounding, the probability of regrading was reduced by beginning with a larger than 500-gram sample. Thus, rounding provides an incentive to take overweight samples in order to avoid regrading. Overweight samples can overestimate the value of peanuts. A low-cost way to improve peanut grading accuracy would be to round to tenths rather than whole numbers.grading, normal-jump distribution, peanuts, regrading, rounding, Crop Production/Industries,
Prediction and benefits of minimal disease activity in patients with psoriatic arthritis and active skin disease in the ADEPT trial
Objectives: To determine the proportion of patients with psoriatic arthritis in the Adalimumab Effectiveness in Psoriatic Arthritis trial achieving minimal disease activity (MDA) and its individual components at 1 or more visits over 144 weeks, identify baseline predictors of MDA achievement, and evaluate the association of MDA status with independent quality of life (QoL)-related patient-reported outcomes (PROs).
Methods: Univariate and multivariate analyses were used to identify the baseline characteristics that predicted achievement of MDA at individual time points (weeks 12 through 144) or sustained MDA (achievement of MDA at 2 consecutive time points 12 weeks apart). The association of independent QoL-related PROs with MDA achievement was evaluated at weeks 24 and 144.
Results: In univariate analyses, higher baseline patient assessment of pain, tender joint count (TJC), enthesitis and Health Assessment Questionnaire-Disability Index (HAQ-DI) score were significantly associated with lower likelihood of achieving MDA at later time points. Multivariate analyses confirmed higher baseline HAQ-DI as a significant predictor for failure to achieve MDA at later time points. Achievement of sustained MDA was associated with lower baseline TJC and HAQ-DI score. Achievement of different MDA components appeared to be treatment dependent. MDA achievers had significantly better QoL-related PROs and greater improvements in PROs from baseline to week 24 compared with non-achievers.
Conclusions: Higher HAQ-DI score was the most consistent baseline factor that decreased the likelihood of achieving MDA and sustained MDA at later time points. Achieving MDA was associated with better independent QoL-related PROs
On the magnetic structure of the solar transition region
We examine the hypothesis that ``cool loops'' dominate emission from solar
transition region plasma below temperatures of K. We compare
published VAULT images of H L, a lower transition region line, with
near-contemporaneous magnetograms from Kitt Peak, obtained during the second
flight (VAULT-2) on 14 June 2002. The measured surface fields and potential
extrapolations suggest that there are too few short loops, and that L
emission is associated with the base regions of longer, coronal loops. VAULT-2
data of network boundaries have an asymmetry on scales larger than
supergranules, also indicating an association with long loops. We complement
the Kitt Peak data with very sensitive vector polarimetric data from the
Spectro-Polarimeter on board Hinode, to determine the influence of very small
magnetic concentrations on our analysis. From these data two classes of
behavior are found: within the cores of strong magnetic flux concentrations ( Mx) associated with active network and plage, small-scale mixed
fields are absent and any short loops can connect just the peripheries of the
flux to cell interiors. Core fields return to the surface via longer, most
likely coronal, loops. In weaker concentrations, short loops can connect
between concentrations and produce mixed fields within network boundaries as
suggested by Dowdy and colleagues. The VAULT-2 data which we examined are
associated with strong concentrations. We conclude that the cool loop model
applies only to a small fraction of the VAULT-2 emission, but we cannot
discount a significant role for cool loops in quieter regions. We suggest a
physical picture for how network L emission may occur through the
cross-field diffusion of neutral atoms from chromospheric into coronal plasma.Comment: Accepted by ApJ, 9 May 200
Enhanced Local Moment Formation in a Chiral Luttinger Liquid
We derive here a stability condition for a local moment in the presence of an
interacting sea of conduction electrons. The conduction electrons are modeled
as a Luttinger liquid in which chirality and spin are coupled. We show that an
Anderson-U defect in such an interacting system can be transformed onto a
nearly-Fermi liquid problem. We find that correlations among the conduction
electrons stabilize the local moment phase. A Schrieffer-Wolff transformation
is then performed which results in an anisotropic exchange interaction
indicative of the Kondo effect in a Luttinger liquid. The ground-state
properties of this model are then equivalent to those of the Kondo model in a
Luttinger liquid.Comment: 11 pages, no figure
Quantum logic gates for coupled superconducting phase qubits
Based on a quantum analysis of two capacitively coupled current-biased
Josephson junctions, we propose two fundamental two-qubit quantum logic gates.
Each of these gates, when supplemented by single-qubit operations, is
sufficient for universal quantum computation. Numerical solutions of the
time-dependent Schroedinger equation demonstrate that these operations can be
performed with good fidelity.Comment: 4 pages, 5 figures, revised for publicatio
Indication, from Pioneer 10/11, Galileo, and Ulysses Data, of an Apparent Anomalous, Weak, Long-Range Acceleration
Radio metric data from the Pioneer 10/11, Galileo, and Ulysses spacecraft
indicate an apparent anomalous, constant, acceleration acting on the spacecraft
with a magnitude cm/s, directed towards the Sun.
Two independent codes and physical strategies have been used to analyze the
data. A number of potential causes have been ruled out. We discuss future
kinematic tests and possible origins of the signal.Comment: Revtex, 4 pages and 1 figure. Minor changes for publicatio
Spectroscopy of Three-Particle Entanglement in a Macroscopic Superconducting Circuit
We study the quantum mechanical behavior of a macroscopic, three-body,
superconducting circuit. Microwave spectroscopy on our system, a resonator
coupling two large Josephson junctions, produced complex energy spectra well
explained by quantum theory over a large frequency range. By tuning each
junction separately into resonance with the resonator, we first observe strong
coupling between each junction and the resonator. Bringing both junctions
together into resonance with the resonator, we find spectroscopic evidence for
entanglement between all three degrees of freedom and suggest a new method for
controllable coupling of distant qubits, a key step toward quantum computation.Comment: 4 pages, 3 figure
Opportunities and conditions to learn (OCL): A conceptual framework
“Opportunity to learn” has evolved into an umbrella phrase for describing a large range of settings, resources, structures, and processes. The aim of this study is to develop a conceptual framework that can accommodate a wide range of opportunities to learn, not just those provided by teachers in classrooms. An inclusive framework can bring together diverse studies about opportunity to learn, increasing synergies and uncovering interconnections, and making more visible marginalized forms of learning. It can also be used as a framework for holding governments, education authorities, and policy makers accountable for providing equitable opportunities and conditions to learn. This article presents a three-dimensional conceptual framework of opportunities and conditions to learn (OCL) that captures (a) notions of what opportunities exist and where those opportunities exist and opportunities offered by whom, as well as (b) a spate of conditions that can shape those opportunities
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