190 research outputs found
The hierarchy problem, radion mass, localization of gravity and 4D effective Newtonian potential in string theory on
We present a systematical study of brane worlds in string theory on
. Starting with the toroidal compactification of the NS/NS sector
in (D+d) dimensions, we first obtain an effective -dimensional action, and
then compactify one of the spatial dimensions by introducing two
orbifold branes as its boundaries. By combining the Gauss-Codacci and Lanczos
equations, we write down explicitly the general gravitational field equations
on each of the two branes, while using distribution theory we express the
matter field equations on the branes in terms of the discontinuities of the
first derivatives of the matter fields. Afterwards, we address three important
issues: (i) the hierarchy problem; (ii) the radion mass; and (iii) the
localization of gravity, the 4-dimensional Newtonian effective potential and
the Yukawa corrections due to the gravitational high-order Kaluza-Klein (KK)
modes. With a very conservative estimation, we find that the radion mass is of
the order of . The gravity is localized on the visible brane, and
the spectrum of the gravitational KK modes is discrete and can be of the order
of TeV. The corrections to the 4-dimensional Newtonian potential from the
higher order of gravitational KK modes are exponentially suppressed and can be
safely neglected in current experiments. In an appendix, we also present a
systematical and pedagogical study of the Gauss-Codacci equations and Israel's
junction conditions across a (D-1)-dimensional hypersurface, which can be
either spacelike or timelike.Comment: Considerably extended, Revtex4, 19 pages, 5 figures, published in
IJMPA, 25, 1661-1698 (2010
A new software tool for carbohydrate microarray data storage, processing, presentation, and reporting
Publisher Copyright: © 2022 The Author(s) 2022. Published by Oxford University Press. This project is supported by Wellcome Trust Biomedical Resource grants (WT099197/Z/12/Z, 108430/Z/15/Z and 218304/Z/19/Z); March of Dimes European Prematurity Research Centre grant 22-FY18-82 and NIH Commons Fund 1U01GM125267-01Glycan microarrays are essential tools in glycobiology and are being widely used for assignment of glycan ligands in diverse glycan recognition systems. We have developed a new software, called Carbohydrate microArray Analysis and Reporting Tool (CarbArrayART), to address the need for a distributable application for glycan microarray data management. The main features of CarbArrayART include: (i) Storage of quantified array data from different array layouts with scan data and array-specific metadata, such as lists of arrayed glycans, array geometry, information on glycan-binding samples, and experimental protocols. (ii) Presentation of microarray data as charts, tables, and heatmaps derived from the average fluorescence intensity values that are calculated based on the imaging scan data and array geometry, as well as filtering and sorting functions according to monosaccharide content and glycan sequences. (iii) Data export for reporting in Word, PDF, and Excel formats, together with metadata that are compliant with the guidelines of MIRAGE (Minimum Information Required for A Glycomics Experiment). CarbArrayART is designed for routine use in recording, storage, and management of any slide-based glycan microarray experiment. In conjunction with the MIRAGE guidelines, CarbArrayART addresses issues that are critical for glycobiology, namely, clarity of data for evaluation of reproducibility and validity.publishersversionpublishe
Some remarks on the dynamical systems approach to fourth order gravity
Building on earlier work, we discuss a general framework for exploring the
cosmological dynamics of Higher Order Theories of Gravity. We show that once
the theory of gravity has been specified, the cosmological equations can be
written as a first-order autonomous system and we give several examples which
illustrate the utility of our method. We also discuss a number of results which
have appeared recently in the literature.Comment: 19 pages, LaTe
Classification of High Intensity Zones of the Lumbar Spine and Their Association with Other Spinal MRI Phenotypes: The Wakayama Spine Study
published_or_final_versio
Search for the decay
We performed a search for the decay with the
E391a detector at KEK. In the data accumulated in 2005, no event was observed
in the signal region. Based on the assumption of
proceeding via parity-violation, we obtained the single event sensitivity to be
, and set an upper limit on the branching ratio to
be at the 90% confidence level. This is a factor of 3.2
improvement compared to the previous results. The results of proceeding via parity-conservation were also presented in this paper
Experimental study of the decay
The first dedicated search for the rare neutral-kaon decay
has been carried out in the E391a experiment at the
KEK 12-GeV proton synchrotron. The final upper limit of 2.6 at
the 90% confidence level was set on the branching ratio for the decay.Comment: 23 pages, 27 figures, accepted for publication as a regular article
in Physical Review
Accelerating Universes in String Theory via Field Redefinition
We study cosmological solutions in the effective heterotic string theory with
-correction terms in string frame. It is pointed out that the
effective theory has an ambiguity via field redefinition and we analyze
generalized effective theories due to this ambiguity. We restrict our analysis
to the effective theories which give equations of motion of second order in the
derivatives, just as "Galileon" field theory. This class of effective actions
contains two free coupling constants. We find de Sitter solutions as well as
the power-law expanding universes in our four-dimensional Einstein frame. The
accelerated expanding universes are always the attractors in the present
dynamical system.Comment: 22 pages, 3 figures, some additional formulae adde
- …