3,192 research outputs found
(De)Constructing Dimensions
We construct renormalizable, asymptotically free, four dimensional gauge
theories that dynamically generate a fifth dimension.Comment: 10 pages, late
Fully Point-wise Convolutional Neural Network for Modeling Statistical Regularities in Natural Images
Modeling statistical regularity plays an essential role in ill-posed image
processing problems. Recently, deep learning based methods have been presented
to implicitly learn statistical representation of pixel distributions in
natural images and leverage it as a constraint to facilitate subsequent tasks,
such as color constancy and image dehazing. However, the existing CNN
architecture is prone to variability and diversity of pixel intensity within
and between local regions, which may result in inaccurate statistical
representation. To address this problem, this paper presents a novel fully
point-wise CNN architecture for modeling statistical regularities in natural
images. Specifically, we propose to randomly shuffle the pixels in the origin
images and leverage the shuffled image as input to make CNN more concerned with
the statistical properties. Moreover, since the pixels in the shuffled image
are independent identically distributed, we can replace all the large
convolution kernels in CNN with point-wise () convolution kernels while
maintaining the representation ability. Experimental results on two
applications: color constancy and image dehazing, demonstrate the superiority
of our proposed network over the existing architectures, i.e., using
1/101/100 network parameters and computational cost while achieving
comparable performance.Comment: 9 pages, 7 figures. To appear in ACM MM 201
Anomalies on Orbifolds
We discuss the form of the chiral anomaly on an S1/Z2 orbifold with chiral
boundary conditions. We find that the 4-divergence of the higher-dimensional
current evaluated at a given point in the extra dimension is proportional to
the probability of finding the chiral zero mode there. Nevertheless the
anomaly, appropriately defined as the five dimensional divergence of the
current, lives entirely on the orbifold fixed planes and is independent of the
shape of the zero mode. Therefore long distance four dimensional anomaly
cancellation ensures the consistency of the higher dimensional orbifold theory.Comment: 11 pages, latex, no figure
Twisted supersymmetry and the topology of theory space
We present examples of four dimensional, non-supersymmetric field theories in
which ultraviolet supersymmetry breaking effects, such as bose-fermi splittings
and the vacuum energy, are suppressed by , where
is a weak coupling factor and can be made arbitrarily large. The particle
content and interactions of these models are conveniently represented by a
graph with sites and links, describing the gauge theory space structure. While
the theories are supersymmetric ``locally'' in theory space, supersymmetry can
be explicitly broken by topological obstructions.Comment: 9 pages, revtex
Recent Decisions
Comments on recent decisions by Joseph C. Spalding, R. Emmett Fitzgerald, Howard G. Burke, Andrew V. Giorgi, Richard F. Welter, Edward L. Burke, Frank A. Howard, Robert C. Enburg, Carl F. Eiberger, William L. Kirchner, Jr., and William J. Hurley
Atmospheric Characterization of the Hot Jupiter Kepler-13Ab
Kepler-13Ab (= KOI-13.01) is a unique transiting hot Jupiter. It is one of
very few known short-period planets orbiting a hot A-type star, making it one
of the hottest planets currently known. The availability of Kepler data allows
us to measure the planet's occultation (secondary eclipse) and phase curve in
the optical, which we combine with occultations observed by warm Spitzer at 4.5
mic and 3.6 mic and a ground-based occultation observation in the Ks band (2.1
mic). We derive a day-side hemisphere temperature of 2,750 +- 160 K as the
effective temperature of a black body showing the same occultation depths.
Comparing the occultation depths with one-dimensional planetary atmosphere
models suggests the presence of an atmospheric temperature inversion. Our
analysis shows evidence for a relatively high geometric albedo, Ag= 0.33 +0.04
-0.06. While measured with a simplistic method, a high Ag is supported also by
the fact that the one-dimensional atmosphere models underestimate the
occultation depth in the optical. We use stellar spectra to determine the
dilution, in the four wide bands where occultation was measured, due to the
visual stellar binary companion 1.15 +- 0.05" away. The revised stellar
parameters measured using these spectra are combined with other measurements
leading to revised planetary mass and radius estimates of Mp = 4.94 - 8.09 Mjup
and Rp = 1.406 +- 0.038 Rjup. Finally, we measure a Kepler mid-occultation time
that is 34.0 +- 6.9 s earlier than expected based on the mid-transit time and
the delay due to light travel time, and discuss possible scenarios.Comment: V2: Accepted to ApJ on 2014 April 11. Spitzer photometry and model
fitting Matlab pipeline code is publicly available at:
http://gps.caltech.edu/~shporer/spitzerphot
Infrared Lightcurves of Near Earth Objects
We present lightcurves and derive periods and amplitudes for a subset of 38
near earth objects (NEOs) observed at 4.5 microns with the IRAC camera on the
the Spitzer Space Telescope, many of them having no previously reported
rotation periods. This subset was chosen from about 1800 IRAC NEO observations
as having obvious periodicity and significant amplitude. For objects where the
period observed did not sample the full rotational period, we derived lower
limits to these parameters based on sinusoidal fits. Lightcurve durations
ranged from 42 to 544 minutes, with derived periods from 16 to 400 minutes. We
discuss the effects of lightcurve variations on the thermal modeling used to
derive diameters and albedos from Spitzer photometry. We find that both
diameters and albedos derived from the lightcurve maxima and minima agree with
our previously published results, even for extreme objects, showing the
conservative nature of the thermal model uncertainties. We also evaluate the
NEO rotation rates, sizes, and their cohesive strengths.Comment: 16 pages, 4 figures, 3 tables, to appear in the Astrophysical Journal
Supplement Serie
PrimPol bypasses UV photoproducts during eukaryotic chromosomal DNA replication
DNA damage can stall the DNA replication machinery, leading to genomic instability. Thus, numerous mechanisms exist to complete genome duplication in the absence of a pristine DNA template, but identification of the enzymes involved remains incomplete. Here, we establish that Primase-Polymerase (PrimPol; CCDC111), an archaeal-eukaryotic primase (AEP) in eukaryotic cells, is involved in chromosomal DNA replication. PrimPol is required for replication fork progression on ultraviolet (UV) lightdamaged DNA templates, possibly mediated by its ability to catalyze translesion synthesis (TLS) of these lesions. This PrimPol UV lesion bypass pathway is not epistatic with the Pol h-dependent pathway and, as a consequence, protects xeroderma pigmentosum variant (XP-V) patient cells from UV-induced cytotoxicity. In addition, we establish that PrimPol is also required for efficient replication fork progression during an unperturbed S phase. These and other findings indicate that PrimPol is an important player in replication fork progression in eukaryotic cells
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