12,400 research outputs found
Non-perturbative renormalization of the axial current with improved Wilson quarks
We present a new normalization condition for the axial current, which is
derived from the PCAC relation with non-vanishing mass.
Using this condition reduces the O(r_0 m) corrections to the axial current
normalization constant Z_A for an easier chiral extrapolation in the cases,
where simulations at zero quark-mass are not possible. The method described
here also serves as a preparation for a determination of Z_A in the full
two-flavor theory.Comment: 3 pages, 3 figures, Lattice2003(improve
Development and screening of selective catalysts for the synthesis of clean liquid fuels
This article is a compilation of the research carried out under EEC contract EN3V-0400-D at the Institut für Energieverfahrenstechnik in Jülich and at the Faculty of Chemical Technology and Materials Science, Delft, concerning the development and screening of copper/cobalt-based catalysts for the synthesis of alcohol mixtures from syngas. Analogous work, based on copper/zinc oxide/alumina catalysts, has been performed at the Faculty of Chemical Technology in Twente University at Enschede. This work is described in a companion paper. Comparative tests of several catalysts in a pressure micropulse reactor and in a plug flow tubular reactor, carried out at the Institut für Technische Chemie, TU Braunschweig, are presented in a second companion paper. \ud
In the discussion section of the present article the results obtained by the joint groups are compared with the initial objectives of the programme
J Fluorescence
The scope of this paper is to illustrate the need for an improved quality assurance in fluorometry. For this purpose, instrumental sources of error and their influences on the reliability and comparability of fluorescence data are highlighted for frequently used photoluminescence techniques ranging from conventional macro- and microfluorometry over fluorescence microscopy and flow cytometry to microarray technology as well as in vivo fluorescence imaging. Particularly, the need for and requirements on fluorescence standards for the characterization and performance validation of fluorescence instruments, to enhance the comparability of fluorescence data, and to enable quantitative fluorescence analysis are discussed. Special emphasis is dedicated to spectral fluorescence standards and fluorescence intensity standards
Operational challenges of engaging development partners in district health planning in Tanzania
BACKGROUND: Development Assistance for Health (DAH) represents an important source of health financing in many low and middle-income countries. However, there are few accounts on how priorities funded through DAH are integrated with district health priorities. This study is aimed at understanding the operational challenges of engaging development partners in district health planning in Tanzania. METHODS: This explanatory mixed-methods study was conducted in Kinondoni and Bahi districts, representing urban and rural settings of the country. Data collection took place between November and December 2015. The quantitative tools (mapping checklist, district questionnaire and Development partners (DPs) questionnaire) mapped the DPs and their activities and gauged the strength of DP engagement in district health planning. The qualitative tool, a semi-structured in-depth interview guide administered to 20 key informants (the council health planning team members and the development partners) explained the barriers and facilitators of engagement. Descriptive and thematic analysis was utilized for quantitative and qualitative data analysis respectively. RESULTS: Eighty-six per cent (85%) of the development partners delivering aid in the studied districts were Non-Governmental Organizations. Twenty percent (20%) of the interventions were HIV/AIDS interventions. We found that only four (4) representing 25 % (25%) DPs had an MOU with the District Council, 56 % (56%) had submitted their plans in writing to be integrated into the 2014/15 CCHP. Six (6) representing 38 % (38%) respondents had received at least one document (guidelines, policies and other planning tools) from the district for them to use in developing their organization activity plans. Eighty-seven point 5 % (87.5%) from Bahi had partial or substantial participation, in the planning process while sixty-two point 5 % (62.5%) from Kinondoni had not participated at all (zero participation). The operational challenges to engagements included differences in planning cycles between the government and donors, uncertainties in funding from the prime donors, lack of transparency, limited skills of district planning teams, technical practicalities on planning tools and processes, inadequate knowledge on planning guidelines among DPs and, poor donor coordination at the district level. CONCLUSIONS: We found low engagement of Development Partners in planning. To be resolved are operational challenges related to differences in planning cycles, articulations and communication of local priorities, donor coordination, and technical skills on planning and stakeholder engagement
Incompatible Magnetic Order in Multiferroic Hexagonal DyMnO3
Magnetic order of the manganese and rare-earth lattices according to
different symmetry representations is observed in multiferroic hexagonal (h-)
DyMnO by optical second harmonic generation and neutron diffraction. The
incompatibility reveals that the 3d-4f coupling in the h-MnO system (
= Sc, Y, In, Dy - Lu) is substantially less developed than commonly expected.
As a consequence, magnetoelectric coupling effects in this type of split-order
parameter multiferroic that were previously assigned to a pronounced 3d-4f
coupling have now to be scrutinized with respect to their origin
The Mean Field Ensemble Kalman Filter: Near-Gaussian Setting
The ensemble Kalman filter is widely used in applications because, for high
dimensional filtering problems, it has a robustness that is not shared for
example by the particle filter; in particular it does not suffer from weight
collapse. However, there is no theory which quantifies its accuracy as an
approximation of the true filtering distribution, except in the Gaussian
setting. To address this issue we provide the first analysis of the accuracy of
the ensemble Kalman filter beyond the Gaussian setting. Our analysis is
developed for the mean field ensemble Kalman filter. We rewrite the update
equations for this filter, and for the true filtering distribution, in terms of
maps on probability measures. We introduce a weighted total variation metric to
estimate the distance between the two filters and we prove various stability
estimates for the maps defining the evolution of the two filters, in this
metric. Using these stability estimates we demonstrate that if the true
filtering distribution is close to Gaussian in the joint space of state and
data, in the weighted total variation metric, then the true-filter is well
approximated by the ensemble Kalman filter, in the same metric. Finally, we
provide a generalization of these results to the Gaussian projected filter,
which can be viewed as a mean field description of the unscented Kalman filter
Ductilisation of tungsten (W) through cold-rolling: Correlation of microstructure and mechanical properties
Deep Learning to Estimate Biological Age From Chest Radiographs
OBJECTIVES The goal of this study was to assess whether a deep learning estimate of age from a chest radiograph image (CXR-Age) can predict longevity beyond chronological age. BACKGROUND Chronological age is an imperfect measure of longevity. Biological age, a measure of overall health, may improve personalized care. This paper proposes a new way to estimate biological age using a convolutional neural network that takes as input a CXR image and outputs a chest x-ray age (in years) as a measure of long-term mortality risk. METHODS CXR-Age was developed using CXR from 116,035 individuals and validated in 2 held-out testing sets: 1) 75% of the CXR arm of PLCO (Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial) (N = 40,967); and 2) the CXR arm of NLST (National Lung Screening Trial) (N = 5,414). CXR-Age was compared to chronological age and a multivariable regression model of chronological age, risk factors, and radiograph findings to predict all-cause and cardiovascular mortality with a maximum 23 years and 13 years of follow-up, respectively. The primary outcome was observed mortality; results are provided for the testing datasets only. RESULTS In the PLCO testing dataset, a 5-year increase in CXR-Age carried a higher risk of all-cause mortality than a 5-year increase in chronological age (CXR-Age hazard ratio [HR]: 2.26 [95% confidence interval (CI): 2.24 to 2.29] vs. chronological age HR: 1.77 [95% CI: 1.75 to 1.78]; p < 0.001). A similar pattern was found for cardiovascular mortality (CXR-Age cause-specific HR: 2.45 per 5 years [95% CI: 2.34 to 2.56] vs. chronological age HR: 1.82 per 5 years [95% CI: 1.74 to 1.90]). Similar results were seen for both outcomes in the NLST external testing dataset. Adding CXR-Age to the multivariable model resulted in significant improvements for predicting both outcomes in both testing datasets (p < 0.001 for all comparisons). CONCLUSIONS Based on a CXR image, CXR-Age predicted long-term all-cause and cardiovascular mortality. (J Am Coll Cardiol Img 2021;14:2226-2236 ) (c) 2021 by the American College of Cardiology Foundation
Ductility in ultrafine-grained (UFG) tungsten foil: Correlation between microstructure and mechanical properties
Magnetoelastic and structural properties of azurite Cu3(CO3)2(OH)2 from neutron scattering and muon spin rotation
Azurite, Cu3(CO3)2(OH)2, has been considered an ideal example of a
one-dimensional (1D) diamond chain antiferromagnet. Early studies of this
material imply the presence of an ordered antiferromagnetic phase below K while magnetization measurements have revealed a 1/3 magnetization
plateau. Until now, no corroborating neutron scattering results have been
published to confirm the ordered magnetic moment structure. We present recent
neutron diffraction results which reveal the presence of commensurate magnetic
order in azurite which coexists with significant magnetoelastic strain. The
latter of these effects may indicate the presence of spin frustration in zero
applied magnetic field. Muon spin rotation, SR, reveals an onset of
short-range order below 3K and confirms long-range order below .Comment: 5 pages, 4 figures, PHYSICAL REVIEW B 81, 140406(R) (2010
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