30,128 research outputs found
Flux and Freund-Rubin Superpotentials in M-theory
We discuss the effective action for weak G_2 compactifications of M-theory.
The presence of fluxes acts as a source for the the axions and drives the
Freund-Rubin parameter to zero. The result is a stable non-supersymmetric
vacuum with a negative cosmological constant. We also give the superpotential
which generates the effective potential and discuss a simple model which aims
to incorporate the effects of supersymmetry breaking by the gauge sector.Comment: Discussion of KK-scale and cosmological scales revise
On the VLBI measurement of the Solar System acceleration
We propose new estimates of the secular aberration drift, mainly due to the
rotation of the Solar System about the Galactic center, based on up-to-date
VLBI observations and and improved method of outlier elimination. We fit
degree-2 vector spherical harmonics to extragalactic radio source proper motion
field derived from geodetic VLBI observations spanning 1979-2013. We pay
particular attention to the outlier elimination procedure to remove outliers
from (i) radio source coordinate time series and (ii) the proper motion sample.
We obtain more accurate values of the Solar system acceleration compared to
those in our previous paper. The acceleration vector is oriented towards the
Galactic center within 7 deg. The component perpendicular to the Galactic plane
is statistically insignificant. We show that an insufficient cleaning of the
data set can lead to strong variations in the dipole amplitude and orientation,
and statistically biased results.Comment: Accepted for publication in A&
Gauge Symmetry and Supersymmetry of Multiple M2-Branes
In previous work we proposed a field theory model for multiple M2-branes
based on an algebra with a totally antisymmetric triple product. In this paper
we gauge a symmetry that arises from the algebra's triple product. We then
construct a supersymmetric theory that is consistent with all the symmetries
expected of a multiple M2-brane theory: 16 supersymmetries, conformal
invariance, and an SO(8) R-symmetry that acts on the eight transverse scalars.
The gauge field is not dynamical. The result is a new type of maximally
supersymmetric gauge theory in three dimensions.Comment: 15 page
Contractile properties of fibroblasts derived from primary frozen shoulder and effects of TGF beta 1 stimulation
INTRODUCTION: Primary Frozen Shoulder (PFS) is a debilitating disease of unknown aetiology. There is fibrosis and contracture of the coracohumeral ligament, tissues of the rotator interval and the glenohumeral ligaments, leading to restrictive shoulder movements requiring surgical intervention [1]. Frozen shoulder has been postulated to be dupuytren’s disease of the shoulder with an association inferred since 1936. The purpose of the study was to test the hypothesis that cellular mechanisms of fibroblasts derived from primary frozen shoulder exhibited similar activity in terms of contraction and response to cytokine (transforming growth factor beta1) to fibroblasts derived from dupuytren’s disease. Understanding of cellular responses is critical to developing non surgical treatment strategies
Dynamic power load simulator
Two independent models simulate dynamic and steady-state responses of electrical and electronic equipment under power load. One is resistance/capacitance/inductance network, and the other is variable resistance analog device. Resistance, inductance, and/or capacitance are selected by iterative process; time-domain response is compared with that of real equipment to select optimal values
- …