7,509 research outputs found
Sigma Decay at Finite Temperature and Density
Sigma decay and its relation with chiral phase transition are discussed at
finite temperature and density in the framework of the Nambu-Jona-Lasinio
model. The decay rate for the process sigma -> 2 pions to first order in a
1/N_c expansion is calculated as a function of temperature T and baryon density
n_b. In particular, only when the chiral phase transition happens around the
tricritical point, the sigma decay results in a non-thermal enhancement of
pions in the final state distributions in relativistic heavy ion collisions.Comment: 6 pages, 3 Postscript figures, submitted to Chin. Phys. Let
Si/SiGe quantum dot with superconducting single-electron transistor charge sensor
We report a robust process for fabrication of surface-gated Si/SiGe quantum
dots (QDs) with an integrated superconducting single-electron transistor
(S-SET) charge sensor. A combination of a deep mesa etch and AlOx backfill is
used to reduce gate leakage. After the leakage current is suppressed, Coulomb
oscillations of the QD and the current-voltage characteristics of the S-SET are
observed at a temperature of 0.3 K. Coupling of the S-SET to the QD is
confirmed by using the S-SET to perform sensing of the QD charge state.Comment: 4 pages, 3 figure
Probabilistic Integration of Object Level Annotations in Chest X-ray Classification
Medical image datasets and their annotations are not growing as fast as their equivalents in the general domain. This makes translation from the newest, more data-intensive methods that have made a large impact on the vision field increasingly more difficult and less efficient. In this paper, we propose a new probabilistic latent variable model for disease classification in chest X-ray images. Specifically we consider chest X-ray datasets that contain global disease labels, and for a smaller subset contain object level expert annotations in the form of eye gaze patterns and disease bounding boxes. We propose a two-stage optimization algorithm which is able to handle these different label granularities through a single training pipeline in a two-stage manner. In our pipeline global dataset features are learned in the lower level layers of the model. The specific details and nuances in the fine-grained expert object-level annotations are learned in the final layers of the model using a knowledge distillation method inspired by conditional variational inference. Subsequently, model weights are frozen to guide this learning process and prevent overfitting on the smaller richly annotated data subsets. The proposed method yields consistent classification improvement across different back-bones on the common benchmark datasets Chest X-ray14 and MIMIC-CXR. This shows how two-stage learning of labels from coarse to fine-grained, in particular with object level annotations, is an effective method for more optimal annotation usage.</p
Phase 1b/2a trial of the superoxide dismutase mimetic GC4419 to reduce chemoradiotherapy-induced oral mucositis in patients with oral cavity or oropharyngeal carcinoma
PURPOSE: To assess the safety of the superoxide dismutase mimetic GC4419 in combination with radiation and concurrent cisplatin for patients with oral cavity or oropharyngeal cancer (OCC) and to assess the potential of GC4419 to reduce severe oral mucositis (OM).
PATIENTS AND METHODS: Patients with locally advanced OCC treated with definitive or postoperative intensity modulated radiation therapy (IMRT) plus cisplatin received GC4419 by 60-minute intravenous infusion, ending \u3c60 minutes before IMRT, Monday through Friday for 3 to 7 weeks, in a dose and duration escalation study. Oral mucositis was assessed twice weekly during and weekly after IMRT.
RESULTS: A total of 46 patients received GC4419 in 11 separate dosing and duration cohorts: dose escalation occurred in 5 cohorts receiving 15 to 112 mg/d over 3 weeks (n=20), duration escalation in 3 cohorts receiving 112 mg/d over 4 to 6 weeks (n=12), and then 3 additional cohorts receiving 30 or 90 mg/d over 6 to 7 weeks (n=14). A maximum tolerated dose was not reached. One dose-limiting toxicity (grade 3 gastroenteritis and vomiting with hyponatremia) occurred in each of 2 separate cohorts at 112 mg. Nausea/vomiting and facial paresthesia during infusion seemed to be GC4419 dose-related. Severe OM occurred through 60 Gy in 4 of 14 patients (29%) dosed for 6 to 7 weeks, with median duration of only 2.5 days.
CONCLUSIONS: The safety of GC4419 concurrently with chemoradiation for OCC was acceptable. Toxicities included nausea/vomiting and paresthesia. Doses of 30 and 90 mg/d administered for 7 weeks were selected for further study. In an exploratory analysis, severe OM seemed less frequent and briefer than expected
Structure of Flux Line Lattices with Weak Disorder at Large Length Scales
Dislocation-free decoration images containing up to 80,000 vortices have been
obtained on high quality BiSrCaCuO superconducting
single crystals. The observed flux line lattices are in the random manifold
regime with a roughening exponent of 0.44 for length scales up to 80-100
lattice constants. At larger length scales, the data exhibit nonequilibrium
features that persist for different cooling rates and field histories.Comment: 4 pages, 3 gif images, to appear in PRB rapid communicatio
The separability of tripartite Gaussian state with amplification and amplitude damping
Tripartite three mode Gaussian state undergoes parametric amplification and
amplitude damping as well as thermal noise is studied. In the case of a state
totally symmetrically interacting with the environment, the time dependent
correlation matrix of the state in evolution is given. The conditions for fully
separability and fully entanglement of the final tripartite three mode Gaussian
state are worked out.Comment: 9 pages, 3 figure
Empirical modeling of the stellar spectrum of galaxies
An empirical method of modeling the stellar spectrum of galaxies is proposed,
based on two successive applications of Principal Component Analysis (PCA). PCA
is first applied to the newly available stellar library STELIB, supplemented by
the J, H and K magnitudes taken mainly from the 2 Micron All Sky Survey
(2MASS). Next the resultant eigen-spectra are used to fit the observed spectra
of a sample of 1016 galaxies selected from the Sloan Digital Sky Survey Data
Release One (SDSS DR1). PCA is again applied, to the fitted spectra to
construct the eigen-spectra of galaxies with zero velocity dispersion. The
first 9 galactic eigen-spectra so obtained are then used to model the stellar
spectrum of the galaxies in SDSS DR1, and synchronously to estimate the stellar
velocity dispersion, the spectral type, the near-infrared SED, and the average
reddening. Extensive tests show that the spectra of different type galaxies can
be modeled quite accurately using these eigen-spectra. The method can yield
stellar velocity dispersion with accuracies better than 10%, for the spectra of
typical S/N ratios in SDSS DR1.Comment: 34 pages with 18 figures, submitted to A
Photoproduction evidence for and against hidden-strangeness states near 2 GeV
Experimental evidence from coherent diffractive proton scattering has been
reported for two narrow baryonic resonances which decay predominantly to
strange particles. These states, with masses close to 2.0 GeV would, if
confirmed, be candidates for hidden strangeness states with unusual internal
structure. In this paper we examine the literature on strangeness
photoproduction, to seek additional evidence for or against these states. We
find that one state is not confirmed, while for the other state there is some
mild supporting evidence favoring its existence. New experiments are called
for, and the expected photoproduction lineshapes are calculated.Comment: 9 pages, RevTex, five postscript figures, submitted to PR
High-Field Electrical Transport in Single-Wall Carbon Nanotubes
Using low-resistance electrical contacts, we have measured the intrinsic
high-field transport properties of metallic single-wall carbon nanotubes.
Individual nanotubes appear to be able to carry currents with a density
exceeding 10^9 A/cm^2. As the bias voltage is increased, the conductance drops
dramatically due to scattering of electrons. We show that the current-voltage
characteristics can be explained by considering optical or zone-boundary phonon
emission as the dominant scattering mechanism at high field.Comment: 4 pages, 3 eps figure
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