2,091 research outputs found
Measurement and models accounting for cell death capture hidden variation in compound response.
Cancer cell sensitivity or resistance is almost universally quantified through a direct or surrogate measure of cell number. However, compound responses can occur through many distinct phenotypic outcomes, including changes in cell growth, apoptosis, and non-apoptotic cell death. These outcomes have divergent effects on the tumor microenvironment, immune response, and resistance mechanisms. Here, we show that quantifying cell viability alone is insufficient to distinguish between these compound responses. Using an alternative assay and drug-response analysis amenable to high-throughput measurement, we find that compounds with identical viability outcomes can have very different effects on cell growth and death. Moreover, additive compound pairs with distinct growth/death effects can appear synergistic when only assessed by viability. Overall, these results demonstrate an approach to incorporating measurements of cell death when characterizing a pharmacologic response
Consistency of hadronic vacuum polarization between lattice QCD and the R ratio
There are emerging tensions for theory results of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment both within recent lattice QCD calculations and between some lattice QCD calculations and R-ratio results. In this paper, we work toward scrutinizing critical aspects of these calculations. We focus in particular on a precise calculation of Euclidean position-space windows defined by RBC/UKQCD that are ideal quantities for cross-checks within the lattice community and with R-ratio results. We perform a lattice QCD calculation using physical up, down, strange, and charm sea quark gauge ensembles generated in the staggered formalism by the MILC Collaboration. We study the continuum limit using inverse lattice spacings from a(-1) approximate to 1.6 GeV to 3.5 GeV, identical to recent studies by FNAL/HPQCD/MILC and Aubin et al. and similar to the recent study of BMW. Our calculation exhibits a tension for the particularly interesting window result of a(mu)(ud,conn.,isospin,W) from 0.4 to 1.0 fm with previous results obtained with a different discretization of the vector current on the same gauge configurations. Our results may indicate a difficulty related to estimating uncertainties of the continuum extrapolation that deserves further attention. In this work, we also provide results for a(mu)(ud,conn.,isospin), a(mu)(s,conn.,isospin), a(mu)(SIB,conn.) for the total contribution and a large set of windows. For the total contribution, we find a(mu)(HVPLO) = 714(27)(13)10(-10), a(mu)(ud,conn.,isospin) 657(26)(12)10(-1)0, a(mu)(s,conn.,isospin) = 52.83(22)(65)10(-1)0, and a(mu)(SIB,conn.) = 9.0(0.8)(1.2)10(-10), where the first uncertainty is statistical and the second systematic. We also comment on finite-volume corrections for the strong-isospin-breaking corrections
Analysis, Visualization, and Transformation of Audio Signals Using Dictionary-based Methods
date-added: 2014-01-07 09:15:58 +0000 date-modified: 2014-01-07 09:15:58 +0000date-added: 2014-01-07 09:15:58 +0000 date-modified: 2014-01-07 09:15:58 +000
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Nucleon mass with highly improved staggered quarks
We present the first computation in a program of lattice-QCD baryon physics using staggered fermions for sea and valence quarks. For this initial study, we present a calculation of the nucleon mass, obtaining with all sources of statistical and systematic errors controlled and accounted for. This result is the most precise determination to date of the nucleon mass from first principles. We use the highly improved staggered quark action, which is computationally efficient. Three gluon ensembles are employed, which have approximate lattice spacings , , and , each with equal-mass , , and quarks in the sea. Further, all ensembles have the light valence and sea quarks tuned to reproduce the physical pion mass, avoiding complications from chiral extrapolations. Our work opens a new avenue for precise calculations of baryon properties, which are both feasible and relevant to experiments in particle and nuclear physics
First measurements of high frequency cross-spectra from a pair of large Michelson interferometers
Measurements are reported of the cross-correlation of spectra of differential
position signals from the Fermilab Holometer, a pair of co-located 39 m long,
high power Michelson interferometers with flat, broadband frequency response in
the MHz range. The instrument obtains sensitivity to high frequency correlated
signals far exceeding any previous measurement in a broad frequency band
extending beyond the 3.8 MHz inverse light crossing time of the apparatus. The
dominant but uncorrelated shot noise is averaged down over
independent spectral measurements with 381 Hz frequency resolution to obtain
sensitivity to stationary
signals. For signal bandwidths kHz, the sensitivity to strain
or shear power spectral density of classical or exotic origin surpasses a
milestone where
is the Planck time.Comment: 5 pages, 3 figure
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Computing nucleon charges with highly improved staggered quarks
This work continues our program of lattice-QCD baryon physics using staggered fermions for both the sea and the valence quarks. We present a proof-of-concept study that demonstrates, for the first time, how to calculate baryon matrix elements using staggered quarks for the valence sector. We show how to relate the representations of the continuum staggered flavor-taste group to those of the discrete lattice symmetry group. The resulting calculations yield the normalization factors relating staggered baryon matrix elements to their physical counterparts. We verify this methodology by calculating the isovector vector and axial-vector charges and . We use a single ensemble from the MILC Collaboration with flavors of sea quark, lattice spacing , and a pion mass . On this ensemble, we find results consistent with expectations from current conservation and neutron beta decay. Thus, this work demonstrates how highly improved staggered quarks can be used for precision calculations of baryon properties and, in particular, the isovector nucleon charges
Interferometric Constraints on Quantum Geometrical Shear Noise Correlations
Final measurements and analysis are reported from the first-generation
Holometer, the first instrument capable of measuring correlated variations in
space-time position at strain noise power spectral densities smaller than a
Planck time. The apparatus consists of two co-located, but independent and
isolated, 40 m power-recycled Michelson interferometers, whose outputs are
cross-correlated to 25 MHz. The data are sensitive to correlations of
differential position across the apparatus over a broad band of frequencies up
to and exceeding the inverse light crossing time, 7.6 MHz. By measuring with
Planck precision the correlation of position variations at spacelike
separations, the Holometer searches for faint, irreducible correlated position
noise backgrounds predicted by some models of quantum space-time geometry. The
first-generation optical layout is sensitive to quantum geometrical noise
correlations with shear symmetry---those that can be interpreted as a
fundamental noncommutativity of space-time position in orthogonal directions.
General experimental constraints are placed on parameters of a set of models of
spatial shear noise correlations, with a sensitivity that exceeds the
Planck-scale holographic information bound on position states by a large
factor. This result significantly extends the upper limits placed on models of
directional noncommutativity by currently operating gravitational wave
observatories.Comment: Matches the journal accepted versio
WALLABY Early Science - I. The NGC 7162 Galaxy Group
We present Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY) early
science results from the Australian Square Kilometre Array Pathfinder (ASKAP)
observations of the NGC 7162 galaxy group. We use archival HIPASS and Australia
Telescope Compact Array (ATCA) observations of this group to validate the new
ASKAP data and the data reduction pipeline ASKAPsoft. We detect six galaxies in
the neutral hydrogen (HI) 21-cm line, expanding the NGC 7162 group membership
from four to seven galaxies. Two of the new detections are also the first HI
detections of the dwarf galaxies, AM 2159-434 and GALEXASC J220338.65-431128.7,
for which we have measured velocities of and km s,
respectively. We confirm that there is extended HI emission around NGC 7162
possibly due to past interactions in the group as indicated by the
offset between the kinematic and morphological major axes for NGC 7162A, and
its HI richness. Taking advantage of the increased resolution (factor of
) of the ASKAP data over archival ATCA observations, we fit a tilted
ring model and use envelope tracing to determine the galaxies' rotation curves.
Using these we estimate the dynamical masses and find, as expected, high dark
matter fractions of for all group members. The
ASKAP data are publicly available.Comment: 20 pages, 11 figures, accepted for publication in MNRA
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