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Evidence of Molecular Evolution Driven by Recombination Events Influencing Tropism in a Novel Human Adenovirus that Causes Epidemic Keratoconjunctivitis
In 2005, a human adenovirus strain (formerly known as HAdV-D22/H8 but renamed here HAdV-D53) was isolated from an outbreak of epidemic keratoconjunctititis (EKC), a disease that is usually caused by HAdV-D8, -D19, or -D37, not HAdV-D22. To date, a complete change of tropism compared to the prototype has never been observed, although apparent recombinant strains of other viruses from species Human adenovirus D (HAdV-D) have been described. The complete genome of HAdV-D53 was sequenced to elucidate recombination events that lead to the emergence of a viable and highly virulent virus with a modified tropism. Bioinformatic and phylogenetic analyses of this genome demonstrate that this adenovirus is a recombinant of HAdV-D8 (including the fiber gene encoding the primary cellular receptor binding site), HAdV-D22, (the Δ determinant of the hexon gene), HAdV-D37 (including the penton base gene encoding the secondary cellular receptor binding site), and at least one unknown or unsequenced HAdV-D strain. Bootscanning analysis of the complete genomic sequence of this novel adenovirus, which we have re-named HAdV-D53, indicated at least five recombination events between the aforementioned adenoviruses. Intrahexon recombination sites perfectly framed the Δ neutralization determinant that was almost identical to the HAdV-D22 prototype. Additional bootscan analysis of all HAdV-D hexon genes revealed recombinations in identical locations in several other adenoviruses. In addition, HAdV-D53 but not HAdV-D22 induced corneal inflammation in a mouse model. Serological analysis confirmed previous results and demonstrated that HAdV-D53 has a neutralization profile representative of the Δ determinant of its hexon (HAdV-D22) and the fiber (HAdV-D8) proteins. Our recombinant hexon sequence is almost identical to the hexon sequences of the HAdV-D strain causing EKC outbreaks in Japan, suggesting that HAdV-D53 is pandemic as an emerging EKC agent. This documents the first genomic, bioinformatic, and biological descriptions of the molecular evolution events engendering an emerging pathogenic adenovirus
Three Family Type IIB Orientifold String Vacua with Non-Abelian Wilson Lines
We address the implementation of non-Abelian Wilson lines in D=4 N=1 Type IIB
orientifold constructions. We present an explicit three-family example with the
gauge group (U(4)xU(2)xSU(2)xSU(2))^2x(U(6)xSp(4))^2 and give the particle
spectrum and the trilinear superpotential. Emphasizing the new subtleties
associated with the introduction of non-Abelian Wilson lines, we show that the
Abelian gauge anomalies are cancelled by the Green-Schwarz-type mechanism, and
calculate the Fayet-Iliopoulos terms and gauge coupling corrections. The
analysis thus sets a stage for further investigations of the phenomenological
implications of this model.Comment: 23 pages, Latex; minor changes, final version to appear in JHE
Multiple Texture Boltzmann Machines
We assess the generative power of the mPoTmodel of [10] with tiled-convolutional weight sharing as a model for visual textures by specifically training on this task, evaluating model performance on texture synthesis and inpainting tasks using quantitative metrics. We also analyze the relative importance of the mean and covariance parts of the mPoT model by comparing its performance to those of its subcomponents, tiled-convolutional versions of the PoT/FoE and Gaussian-Bernoulli restricted Boltzmann machine (GB-RBM). Our results suggest that while state-of-the-art or better performance can be achieved using the mPoT, similar performance can be achieved with the mean-only model. We then develop a model for multiple textures based on the GB-RBM, using a shared set of weights but texturespecific hidden unit biases. We show comparable performance of the multiple texture model to individually trained texture models.
D=4, N=1 orientifolds with vector structure
We construct compact type IIB orientifolds with discrete groups Z_4, Z_6,
Z_6', Z_8, Z_12 and Z_12'. These models are N=1 supersymmetric in D=4 and have
vector structure. The possibility of having vector structure in Z_N
orientifolds with even N arises due to an alternative Omega-projection in the
twisted sectors. Some of the models without vector structure are known to be
inconsistent because of uncancelled tadpoles. We show that vector structure
leads to a sign flip in the twisted Klein bottle contribution. As a
consequence, all the tadpoles can be cancelled by introducing D9-branes and
D5-branes.Comment: Latex, 44 pages, 2 figures, v2: misprints and an error concerning
Omega^2_{95} corrected, a comment on D5-branes with negative NSNS charge
added, references and acknowledgements adde
Unstable states in QED of strong magnetic fields
We question the use of stable asymptotic scattering states in QED of strong
magnetic fields. To correctly describe excited Landau states and photons above
the pair creation threshold the asymptotic fields are chosen as generalized
Licht fields. In this way the off-shell behavior of unstable particles is
automatically taken into account, and the resonant divergences that occur in
scattering cross sections in the presence of a strong external magnetic field
are avoided. While in a limiting case the conventional electron propagator with
Breit-Wigner form is obtained, in this formalism it is also possible to
calculate -matrix elements with external unstable particles.Comment: Revtex, 7 pages. To appear in Phys. Rev. D53(2
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