6,359 research outputs found
Near-Horizon Extremal Geometries: Coadjoint Orbits and Quantization
The NHEG algebra is an extension of Virasoro introduced in
[arXiv:1503.07861]; it describes the symplectic symmetries of
-dimensional Near Horizon Extremal Geometries with isometry. In this work we construct the NHEG group and classify the
(coadjoint) orbits of its action on phase space. As we show, the group consists
of maps from an -torus to the Virasoro group, so its orbits are bundles of
standard Virasoro coadjoint orbits over . We also describe the unitary
representations that are expected to follow from the quantization of these
orbits, and display their characters. Along the way we show that the NHEG
algebra can be built from u(1) currents using a twisted Sugawara construction.Comment: 22 pages, one figure. v2: Title expanded, various minor
clarifications added. Published in JHE
Many lives of KATs - detector, integrator and modulator of cellular environment
Research over the past three decades has firmly established lysine acetyltransferases (KATs) as central players in regulating transcription. Recent advances in genomic sequencing, metabolomics, animal models and mass spectrometry technologies have uncovered unexpected new roles for KATs at the nexus between the environment and transcriptional regulation. Thousands of reversible acetylation sites have been mapped in the proteome that respond dynamically to the cellular milieu and maintain major processes such as metabolism, autophagy and stress response. Concurrently, researchers are continuously uncovering how deregulation of KAT activity drives disease, including cancer and developmental syndromes characterized by severe intellectual disability. These novel findings are reshaping our view of KATs away from mere modulators of chromatin to detectors of the cellular environment and integrators of diverse signalling pathways with the ability to modify cellular phenotype
A study to evaluate the efficacy of combined prostaglandins and vaginal estradiol compared to prostaglandin alone in labor induction
Background: Induction of labor (IOL) is a process where labor is initiated artificially before its spontaneous onset for the delivery of feto placental unit by mechanical or pharmacologic methods.Methods: The present Hospital based prospective randomized comparative study was conducted in the department of obstetrics and gynecology, KLES Dr. Prabhakar Kore Charitable Hospital, Belagavi during the period of January 2015 to December 2015.The selected women were randomized into two groups by simple randomization using an opaque sealed envelope, into either without vaginal estradiol Group A: Group PGE2 - Prostaglandin E2 gel intracervical alone group or Group B: PGE2 + E (Estradiol) - combined Prostaglandin E2 gel intracervical and 50 ”g of estradiol tablet intravaginal group.Results: In the present study 65% of the women in group PGE2 required three doses of prostaglandins compared to 23.33% in group PGE2 and estradiol for the cervix to become favorable. In this study there is significantly longer mean interval time noted for induction to cervical ripening (12.88±4.91 versus 8.92±5.07; p <0.001), induction to active labor (16.97±4.93 versus 11.02±4.72; p <0.001) and induction to delivery time (21.97±3.83 versus 13.14±4.98; p <0.001) in group PGE2 compared to combined PGE2 and estradiol group.Conclusions: Thus, vaginal estradiol along with prostaglandins has the potential in cervical ripening and induce labor and in an efficacious way. There is beneficial fetal outcome when combined vaginal estradiol along with intracervical prostaglandin E2 was used
Gravitational Waves from Preheating in M-flation
Matrix inflation, or M-flation, is a string theory motivated inflationary
model with three scalar field matrices and gauge fields in the adjoint
representation of the gauge group. One of these scalars
appears as the effective inflaton while the rest of the fields (scalar and
gauge fields) can play the role of isocurvature fields during inflation and
preheat fields afterwards. There is a region in parameter space and initial
field values, "the hilltop region," where predictions of the model are quite
compatible with the recent Planck data. We show that in this hilltop region, if
the inflaton ends up in the supersymmetric vacuum, the model can have an
embedded preheating mechanism. Couplings of the preheat modes are related to
the inflaton self-couplings and therefore are known from the CMB data. Through
lattice simulations performed using a symplectic integrator, we numerically
compute the power spectra of gravitational waves produced during the preheating
stage following M-flation. The preliminary numerical simulation of the spectrum
from multi-preheat fields peaks in the GHz band with an amplitude
, suggesting that the model has
concrete predictions for the ultra-high frequency gravity-wave probes. This
signature could be used to distinguish the model from rival inflationary modelsComment: v1:27 pages and 7 figures; v2: typos corrected; v3: references added;
v4: matched the JCAP versio
HEVC based Multi-View Video Codec using Frame Interleaving technique
this paper presents a HEVC based multi-view video codec. The frames of the multi-view videos are interleaved to generate a monoscopic video sequence. The interleaving is conducted in a way to increase the exploitation of the temporal and inter-views correlations. The MV-HEVC standard codec is configured to work as a single layered codec, which functions as a monoscipic HEVC codec with AVC capabilities, and used to encode interleaved multi-view video frames. The performance of the codec is compared with the anchor standard MV-HEVC codec by coding the three standard multi-view video sequences: âBalloonâ, âKendoâ and âNewspaper1â. Experimental results show the proposed codec out performs the anchor standard MV-HEVC codec in term of bitrate and PSNR
A note on the M2-M5 brane system and fuzzy spheres
This note covers various aspects of recent attempts to describe membranes
ending on fivebranes using fuzzy geometry. In particular, we examine the
Basu-Harvey equation and its relation to the Nahm equation as well as the
consequences of using a non-associative algebra for the fuzzy three-sphere.
This produces the tantalising result that the fuzzy funnel solution
corresponding to Q coincident membranes ending on a five-brane has
degrees of freedom.Comment: 17 pages, late
Measuring emission coordinates in a pulsar-based relativistic positioning system
A relativistic deep space positioning system has been proposed using four or
more pulsars with stable repetition rates. (Each pulsar emits pulses at a fixed
repetition period in its rest frame.) The positioning system uses the fact that
an event in spacetime can be fully described by emission coordinates: the
proper emission time of each pulse measured at the event. The proper emission
time of each pulse from four different pulsars---interpolated as
necessary---provides the four spacetime coordinates of the reception event in
the emission coordinate system. If more than four pulsars are available, the
redundancy can improve the accuracy of the determination and/or resolve
degeneracies resulting from special geometrical arrangements of the sources and
the event.
We introduce a robust numerical approach to measure the emission coordinates
of an event in any arbitrary spacetime geometry. Our approach uses a continuous
solution of the eikonal equation describing the backward null cone from the
event. The pulsar proper time at the instant the null cone intersects the
pulsar world line is one of the four required coordinates. The process is
complete (modulo degeneracies) when four pulsar world lines have been crossed
by the light cone.
The numerical method is applied in two different examples: measuring emission
coordinates of an event in Minkowski spacetime using pulses from four pulsars
stationary in the spacetime; and measuring emission coordinates of an event in
Schwarzschild spacetime using pulses from four pulsars freely falling toward a
static black hole.
These numerical simulations are merely exploratory, but with improved
resolution and computational resources the method can be applied to more
pertinent problems. For instance one could measure the emission coordinates,
and therefore the trajectory, of the Earth.Comment: 9 pages, 2 figures, v3: replaced with version accepted by Phys. Rev.
p-p' System with B-field, Branes at Angles and Noncommutative Geometry
We study the generic system in the presence of constant NS
2-form field. We derive properties concerning with the
noncommutativity of D-brane worldvolume, the Green functions and the spectrum
of this system. In the zero slope limit, a large number of light states appear
as the lowest excitations in appropriate cases. We are able to relate the
energies of the lowest states after the GSO projection with the configurations
of branes at angles. Through analytic continuation, the system is compared with
the branes with relative motion.Comment: 21 pages, Latex. References regarding to section 3 and 4 added. Typos
correcte
Human Re-identification with Global and Local Siamese Convolution Neural Network
Human re-identification is an important task in surveillance system to determine whether the same human re-appears in multiple cameras with disjoint views. Mostly, appearance based approaches are used to perform human re-identification task because they are less constrained than biometric based approaches. Most of the research works apply hand-crafted feature extractors and then simple matching methods are used. However, designing a robust and stable feature requires expert knowledge and takes time to tune the features. In this paper, we propose a global and local structure of Siamese Convolution Neural Network which automatically extracts features from input images to perform human re-identification task. Besides, most of the current human re-identification task in single-shot approaches do not consider occlusion issue due to lack of tracking information. Therefore, we apply a decision fusion technique to combine global and local features for occlusion cases in single-shot approaches
The non-specific lethal (NSL) complex at the crossroads of transcriptional control and cellular homeostasis
The functionality of chromatin is tightly regulated by post-translational modifications that modulate transcriptional output from target loci. Among the post-translational modifications of chromatin, reversible Δ-lysine acetylation of histone proteins is prominent at transcriptionally active genes. Lysine acetylation is catalyzed by lysine acetyltransferases (KATs), which utilize the central cellular metabolite acetyl-CoA as their substrate. Among the KATs that mediate lysine acetylation, males absent on the first (MOF/KAT8) is particularly notable for its ability to acetylate histone 4 lysine 16 (H4K16ac), a modification that decompacts chromatin structure. MOF and its non-specific lethal (NSL) complex members have been shown to localize to gene promoters and enhancers in the nucleus, as well as to microtubules and mitochondria to regulate key cellular processes. Highlighting their importance, mutations or deregulation of NSL complex members has been reported in both human neurodevelopmental disorders and cancer. Based on insight gained from studies in human, mouse, and Drosophila model systems, this review discusses the role of NSL-mediated lysine acetylation in a myriad of cellular functions in both health and disease. Through these studies, the importance of the NSL complex in regulating core transcriptional and signaling networks required for normal development and cellular homeostasis is beginning to emerge
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