1,120 research outputs found
Effects of non-universal large scales on conditional structure functions in turbulence
We report measurements of conditional Eulerian and Lagrangian structure
functions in order to assess the effects of non-universal properties of the
large scales on the small scales in turbulence. We study a 1m 1m
1.5m flow between oscillating grids which produces
while containing regions of nearly homogeneous and highly inhomogeneous
turbulence. Large data sets of three-dimensional tracer particle velocities
have been collected using stereoscopic high speed cameras with real-time image
compression technology. Eulerian and Lagrangian structure functions are
measured in both homogeneous and inhomogeneous regions of the flow. We
condition the structure functions on the instantaneous large scale velocity or
on the grid phase. At all scales, the structure functions depend strongly on
the large scale velocity, but are independent of the grid phase. We see clear
signatures of inhomogeneity near the oscillating grids, but even in the
homogeneous region in the center we see a surprisingly strong dependence on the
large scale velocity that remains at all scales. Previous work has shown that
similar correlations extend to very high Reynolds numbers. Comprehensive
measurements of these effects in a laboratory flow provide a powerful tool for
assessing the effects of shear, inhomogeneity and intermittency of the large
scales on the small scales in turbulence
Short-term leprosy forecasting from an expert opinion survey.
We conducted an expert survey of leprosy (Hansen's Disease) and neglected tropical disease experts in February 2016. Experts were asked to forecast the next year of reported cases for the world, for the top three countries, and for selected states and territories of India. A total of 103 respondents answered at least one forecasting question. We elicited lower and upper confidence bounds. Comparing these results to regression and exponential smoothing, we found no evidence that any forecasting method outperformed the others. We found evidence that experts who believed it was more likely to achieve global interruption of transmission goals and disability reduction goals had higher error scores for India and Indonesia, but lower for Brazil. Even for a disease whose epidemiology changes on a slow time scale, forecasting exercises such as we conducted are simple and practical. We believe they can be used on a routine basis in public health
System Design and Implementation of a National Image Registry for Orthopaedic Oncology Image Management, Research and Teaching
Orthopaedic oncology is highly dependent on imaging studies to diagnose and treat patients. However, many types of bone tumors are rare creating a lack of teaching and research cases. We have developed a system to locally document and nationally register electronic images for teaching and research on bone tumors. The system minimizes storage requirements and maintains confidentiality using a unique approach. This paper demonstrates the system design and current implementation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46052/1/10796_2004_Article_5150940.pd
A bibliometric search of citation classics in anesthesiology
BACKGROUND: Articles cited counts are catalogued and help identify landmark papers. This study provides a citation classics of anesthesiology literature using the framework of subspecialties to provide a review of well-developed areas of research in anesthesiology. METHODS: A comprehensive list of the most-cited articles in anesthesia was compiled using a bibliometric database and general search terms such as "anesthesia" as well as subspecialty-specific search terms. Queries were reviewed for relevance to anesthesiology practice, categorized by subspecialty, and ranked according to their citation counts. RESULTS: The database resulted in 2519 articles published between 1945 and 2008. The specialty areas most represented were chronic pain medicine (11%), pharmacology (9%), and pain sciences (9%). CONCLUSIONS: This citations classic allows for advances in anesthesiology and its subspecialties to be highlighted as well to provide useful manuscripts to guide patient care, direct future research, and serve as sources for future academic pursuit
Nucleon isovector structure functions in (2+1)-flavor QCD with domain wall fermions
We report on numerical lattice QCD calculations of some of the low moments of
the nucleon structure functions. The calculations are carried out with gauge
configurations generated by the RBC and UKQCD collaborations with (2+1)-flavors
of dynamical domain wall fermions and the Iwasaki gauge action (). The inverse lattice spacing is GeV, and two spatial
volumes of ((2.7{\rm fm})^3) and ((1.8 {\rm fm})^3) are used. The up and down
quark masses are varied so the pion mass lies between 0.33 and 0.67 GeV while
the strange mass is about 12 % heavier than the physical one. The structure
function moments we present include fully non-perturbatively renormalized
iso-vector quark momentum fraction, (_{u-d}), helicity fraction, (< x
>_{\Delta u - \Delta d}), and transversity, (_{\delta u - \delta d}), as
well as an unrenormalized twist-3 coefficient, (d_1). The ratio of the momentum
to helicity fractions, (_{u-d}/_{\Delta u - \Delta d}), does not show
dependence on the light quark mass and agrees well with the value obtained from
experiment. Their respective absolute values, fully renormalized, show
interesting trends toward their respective experimental values at the lightest
quark mass. A prediction for the transversity, (0.7 _{\delta u -\delta
d} < 1.1), in the (\bar{\rm MS}) scheme at 2 GeV is obtained. The twist-3
coefficient, (d_1), though yet to be renormalized, supports the perturbative
Wandzura-Wilczek relation.Comment: 14 pages, 22 figures
A Comparative Study of the Properties of Polar and Nonpolar Solvent/Solute/Polystyrene Solutions in Microwave Fields Via Molecular Dynamics
The influence of an applied microwave field on the dynamics of methylamine-dichloromethane (DCM) mixtures bound within atactic polystyrene (a-PS) over a range of polymer densities from 30 to 94 wt % polymer was examined using atomistic molecular dynamics simulations. This study is an extension of previous studies on methylamine transport in relatively polar polystyrene solutions of methanol and dimethylformamide [M. J. Purdue et al., J. Chem. Phys. 124, 204904 (2006)]. A direct comparison is made across the three types of polystyrene solutions. Consideration is given to both solvent and reagent transport within the polymer solutions under zero-field conditions and in an external electromagnetic field in the canonical ensemble (NVT) at 298.0 K. Various frequencies up to 104 GHz and a rms electric field intensity of 0.1 V/Å were applied. The simulation studies were validated by comparison of the simulated zero-field self-diffusion coefficients of DCM in a-PS with those obtained using pulsed-gradient spin-echo NMR spectrometry. Athermal effects of microwave fields on solute transport behavior within polymer solutions are discussed
Molecular Dynamics of Polystyrene Solutions in Microwave Fields
Equilibrium and nonequilibrium molecular dynamics simulation techniques were used to assess the influence of an applied microwave field on the dynamics of methylamine-methanol and methylamine-dimethylformamide (DMF) solutions bound within atactic polystyrene over a range of polymer densities from 35 to 96 wt % polymer. Atomistically detailed systems were studied, ranging from 3000 to 10 644 particles, using previously established potential models. Structural and dynamical properties were determined in the canonical (NVT) ensemble at 298 K. The simulated DMF self-diffusion coefficients in polystyrene solutions were compared with the zero-field experimental results established with pulsed-gradient spin-echo NMR spectrometry. A simulated external microwave field, with a rms electric field intensity of 0.1 V/Å, was applied to these systems and the simulated dynamical results over field frequencies up to 104 GHz were compared with the zero-field values. Simulated evidence of athermal effects on the diffusive characteristics of these mixtures is reported
Quenched hadron spectroscopy with improved staggered quark action
We investigate light hadron spectroscopy with an improved quenched staggered
quark action. We compare the results obtained with an improved gauge plus an
improved quark action, an improved gauge plus standard quark action, and the
standard gauge plus standard quark action. Most of the improvement in the
spectroscopy results is due to the improved gauge sector. However, the improved
quark action substantially reduces violations of Lorentz invariance, as
evidenced by the meson dispersion relations.Comment: New references adde
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