42,035 research outputs found
Remote spectral imaging with simultaneous extraction of 3D topography for historical wall paintings
PRISMS (Portable Remote Imaging System for Multispectral Scanning) is designed for in situ, simultaneous high resolution spectral and 3D topographic imaging of wall paintings and other large surfaces. In particular, it can image at transverse resolutions of tens of microns remotely from distances of tens of metres, making high resolution imaging possible from a fixed position on the ground for areas at heights that is difficult to access. The spectral imaging system is fully automated giving 3D topographic mapping at millimetre accuracy as a by-product of the image focusing process. PRISMS is the first imaging device capable of both 3D mapping and spectral imaging simultaneously without additional distance measuring devices. Examples from applications of PRISMS to wall paintings at a UNESCO site in the Gobi desert are presented to demonstrate the potential of the instrument for large scale 3D spectral imaging, revealing faded writing and material identification
Intrinsic electronic superconducting phases at 60 K and 90 K in double-layer YBaCuO
We study superconducting transition temperature () of oxygen-doped
double-layer high-temperature superconductors YBaCuO (0
1) as a function of the oxygen dopant concentration
() and planar hole-doping concentration (). We find that ,
while clearly influenced by the development of the chain ordering as seen in
the plot, lies on a universal curve originating at the
critical hole concentration () = 1/16 in the plot.
Our analysis suggests that the universal behavior of () can be
understood in terms of the competition and collaboration of chemical-phases and
electronic-phases that exist in the system. We conclude that the global
superconductivity behavior of YBaCuO as a function of
doping is electronically driven and dictated by pristine electronic phases at
magic doping numbers that follow the hierarchical order based on , such as
2 , 3 and 4 . We find that there are
at least two intrinsic electronic superconducting phases of = 60 K at 2
= 1/8 and = 90 K at 3 = 3/16.Comment: 4 pages, 2 figure
c-Axis longitudinal magnetoresistance of the electron-doped superconductor Pr1.85Ce0.15CuO4
We report c-axis resistivity and longitudinal magnetoresistance measurements
of superconducting Pr1.85Ce0.15CuO4 single crystals. In the temperature range
13K<T<32K, a negative magnetoresistance is observed at fields just above Hc2.
Our studies suggest that this negative magnetoresistance is caused by
superconducting fluctuations. At lower temperatures (T<13K), a different
magnetoresistance behavior and a resistivity upturn are observed, whose origin
is still unknown.Comment: Accepted for publication in Phys. Rev.
Automating Carotid Intima-Media Thickness Video Interpretation with Convolutional Neural Networks
Cardiovascular disease (CVD) is the leading cause of mortality yet largely
preventable, but the key to prevention is to identify at-risk individuals
before adverse events. For predicting individual CVD risk, carotid intima-media
thickness (CIMT), a noninvasive ultrasound method, has proven to be valuable,
offering several advantages over CT coronary artery calcium score. However,
each CIMT examination includes several ultrasound videos, and interpreting each
of these CIMT videos involves three operations: (1) select three end-diastolic
ultrasound frames (EUF) in the video, (2) localize a region of interest (ROI)
in each selected frame, and (3) trace the lumen-intima interface and the
media-adventitia interface in each ROI to measure CIMT. These operations are
tedious, laborious, and time consuming, a serious limitation that hinders the
widespread utilization of CIMT in clinical practice. To overcome this
limitation, this paper presents a new system to automate CIMT video
interpretation. Our extensive experiments demonstrate that the suggested system
significantly outperforms the state-of-the-art methods. The superior
performance is attributable to our unified framework based on convolutional
neural networks (CNNs) coupled with our informative image representation and
effective post-processing of the CNN outputs, which are uniquely designed for
each of the above three operations.Comment: J. Y. Shin, N. Tajbakhsh, R. T. Hurst, C. B. Kendall, and J. Liang.
Automating carotid intima-media thickness video interpretation with
convolutional neural networks. CVPR 2016, pp 2526-2535; N. Tajbakhsh, J. Y.
Shin, R. T. Hurst, C. B. Kendall, and J. Liang. Automatic interpretation of
CIMT videos using convolutional neural networks. Deep Learning for Medical
Image Analysis, Academic Press, 201
Hyperon polarization in e^-p --> e^-HK with polarized electron beams
We apply the picture proposed in a recent Letter for transverse hyperon
polarization in unpolarized hadron-hadron collisions to the exclusive process
e^-p --> e^-HK such as e^-p-->e^-\Lambda K^+, e^-p --> e^-\Sigma^+ K^0, or
e^-p--> e^-\Sigma^0 K^+, or the similar process e^-p\to e^-n\pi^+ with
longitudinally polarized electron beams. We present the predictions for the
longitudinal polarizations of the hyperons or neutron in these reactions, which
can be used as further tests of the picture.Comment: 15 pages, 2 figures. submitted to Phys. Rev.
Local tunneling spectroscopy of the electron-doped cuprate Sm1.85Ce0.15CuO4
We present local tunneling spectroscopy in the optimally electron-doped
cuprate Sm2-xCexCuO4 x=0.15. A clear signature of the superconducting gap is
observed with an amplitude ranging from place to place and from sample to
sample (Delta~3.5-6meV). Another spectroscopic feature is simultaneously
observed at high energy above \pm 50meV. Its energy scale and temperature
evolution is found to be compatible with previous photoemission and optical
experiments. If interpreted as the signature of antiferromagnetic order in the
samples, these results could suggest the coexistence on the local scale of
antiferromagnetism and superconductivity on the electron-doped side of cuprate
superconductors
On the variational limits of lattice energies on prestrained elastic bodies
We study the asymptotic behaviour of the discrete elastic energies in
presence of the prestrain metric , assigned on the continuum reference
configuration . When the mesh size of the discrete lattice in
goes to zero, we obtain the variational bounds on the limiting (in the sense of
-limit) energy. In case of the nearest-neighbour and
next-to-nearest-neibghour interactions, we derive a precise asymptotic formula,
and compare it with the non-Euclidean model energy relative to
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