1,049 research outputs found
The holographic RG flow in a field theory on a curved background
As shown by Freedman, Gubser, Pilch and Warner, the RG flow in
super-Yang-Mills theory broken to an theory by the addition of a
mass term can be described in terms of a supersymmetric domain wall solution in
five-dimensional gauged supergravity. The FGPW flow is an example
of a holographic RG flow in a field theory on a flat background. Here we put
the field theory studied by Freedman, Gubser, Pilch and Warner on a curved
background, and we construct the supersymmetric domain wall solution
which describes the RG flow in this field theory. This solution is a curved
(non Ricci flat) domain wall solution. This example demonstrates that
holographic RG flows in supersymmetric field theories on a curved
background can be described in terms of curved supersymmetric domain wall
solutions.Comment: 14 pages, LaTe
Superspace formulations of ten-dimensional supergravity
We present a new formulation for N=1, D=10 supergravity in superspace, in
presence of a Lorentz Chern-Simons-form. This formulation entails the following
properties: it furnishes a solution of the Bianchi identities that is
algebraically consistent to all orders in alpha'; at first order it is the
simplest formulation proposed so far, and it is therefore most suitable for an
explicit higher order analysis; it allows a well defined perturbative expansion
in alpha', in which no poltergeist fields appear; it reconciles the two
different classes of first order solutions available in the literature, that
until now appeared physically inequivalent.Comment: 22 pages, no figures, references and comments adde
Kullback-Leibler and Renormalized Entropy: Applications to EEGs of Epilepsy Patients
Recently, renormalized entropy was proposed as a novel measure of relative
entropy (P. Saparin et al., Chaos, Solitons & Fractals 4, 1907 (1994)) and
applied to several physiological time sequences, including EEGs of patients
with epilepsy. We show here that this measure is just a modified
Kullback-Leibler (K-L) relative entropy, and it gives similar numerical results
to the standard K-L entropy. The latter better distinguishes frequency contents
of e.g. seizure and background EEGs than renormalized entropy. We thus propose
that renormalized entropy might not be as useful as claimed by its proponents.
In passing we also make some critical remarks about the implementation of these
methods.Comment: 15 pages, 4 Postscript figures. Submitted to Phys. Rev. E, 199
D terms from D-branes, gauge invariance and moduli stabilization in flux compactifications
We elucidate the structure of D terms in N=1 orientifold compactifications
with fluxes. As a case study, we consider a simple orbifold of the type-IIA
theory with D6-branes at angles, O6-planes and general NSNS, RR and
Scherk-Schwarz geometrical fluxes. We examine in detail the emergence of D
terms, in their standard supergravity form, from an appropriate limit of the
D-brane action. We derive the consistency conditions on gauged symmetries and
general fluxes coming from brane-localized Bianchi identities, and their
relation with the Freed-Witten anomaly. We extend our results to other N=1
compactifications and to non-geometrical fluxes. Finally, we discuss the
possible role of U(1) D terms in the stabilization of the untwisted moduli from
the closed string sector.Comment: 1+31 pages, 1 figur
HOPX functions as a tumour suppressor in head and neck cancer.
Head and neck squamous cell carcinoma (HNSCC) is generalized term that encompasses a diverse group of cancers that includes tumours of the oral cavity (OSCC), oropharynx (OPSCC) and nasopharynx (NPC). Genetic alterations that are common to all HNSCC types are likely to be important for squamous carcinogenesis. In this study, we have investigated the role of the homeodomain-only homeobox gene, HOPX, in the pathogenesis of HNSCC. We show that HOPX mRNA levels are reduced in OSCC and NPC cell lines and tissues and there is a general reduction of HOPX protein expression in these tumours and OPSCCs. HOPX promoter methylation was observed in a subset of HNSCCs and was associated with a worse overall survival in HPV negative tumours. RNAseq analysis of OSCC cells transfected with HOPX revealed a widespread deregulation of the transcription of genes related to epithelial homeostasis and ectopic over-expression of HOPX in OSCC and NPC cells inhibited cell proliferation, plating efficiency and migration, and enhanced sensitivity to UVA-induced apoptosis. Our results demonstrate that HOPX functions as a tumour suppressor in HNSCC and suggest a central role for HOPX in suppressing epithelial carcinogenesis
Thrombus Imaging Characteristics to Predict Early Recanalization in Anterior Circulation Large Vessel Occlusion Stroke
The early management of transferred patients with a large vessel occlusion (LVO) stroke could be improved by identifying patients who are likely to recanalize early. We aim to predict early recanalization based on patient clinical and thrombus imaging characteristics. We included 81 transferred anterior-circulation LVO patients with an early recanalization, defined as the resolution of the LVO or the migration to a distal location not reachable with endovascular treatment upon repeated radiological imaging. We compared their clinical and imaging characteristics with all (322) transferred patients with a persistent LVO in the MR CLEAN Registry. We measured distance from carotid terminus to thrombus (DT), thrombus length, density, and perviousness on baseline CT images. We built logistic regression models to predict early recanalization. We validated the predictive ability by computing the median area-under-the-curve (AUC) of the receiver operating characteristics curve for 100 5-fold cross-validations. The administration of intravenous thrombolysis (IVT), longer transfer times, more distal occlusions, and shorter, pervious, less dense thrombi were characteristic of early recanalization. After backward elimination, IVT administration, DT and thrombus density remained in the multivariable model, with an AUC of 0.77 (IQR 0.72â0.83). Baseline thrombus imaging characteristics are valuable in predicting early recanalization and can potentially be used to optimize repeated imaging workflow.</p
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