9,144 research outputs found
Type 1 2HDM as effective theory of supersymmetry
It is generally believed that the low energy effective theory of the minimal
supersymmetric standard model is the type 2 two Higgs doublet model. We will
show that the type 1 two Higgs doublet model can also as the effective of
supersymmetry in a specific case with high scale supersymmetry breaking and
gauge mediation. If the other electroweak doublet obtain the vacuum expectation
value after the electroweak symmetry breaking, the Higgs spectrum is quite
different. A remarkable feature is that the physical Higgs boson mass can 125
GeV unlike in the ordinary models with high scale supersymmetry in which the
Higgs mass is generally around 140 GeV.Comment: 11 pages, 3 figures, Published in Commun.Theor.Phy
Supersymmetric Boost on Intersecting D-branes
We study the effect of the Born-Infeld electric field on the supersymmetric
configuration of various composite D-branes. We show that the generic values of
the electric field do not affect the supersymmetry but, as it approaches
keeping the magnetic field finite, various combinations of the
magnetic fields allow up to 8 supersymmetries. We also explore the unbroken
supersymmetries for two intersecting D-strings which are in uniform or relative
motion. For a finite uniform Lorentz boost, 16 supersymmetries are guaranteed
only when they are parallel. For an infinite one, 8 supersymmetries are
preserved only when both the D-strings are oriented to the forward or backward
direction of the boost. Under a finite relative boost, 8 supersymmetries are
preserved only when the intersecting angle is less than and the
intersecting point moves at the speed of light. As for an infinite relative
boost, 8 supersymmetries are preserved regardless of the values of the
intersecting angle.Comment: 27 pages using REVTeX4, 7 figure
Wettability characteristics of an Al2O3/SiO2-based ceramic modified with CO2, Nd:YAG, excimer and high-power diode lasers
Interaction of CO2, Nd:YAG, excimer and high power diode laser (HPDL) radiation with the
surface of an Al2O3/SiO2 based ceramic was found to effect significant changes in the
wettability characteristics of the material. It was observed that interaction with CO2, Nd:YAG
and HPDL radiation reduced the enamel contact angle from 1180 to 310, 340 and 330
respectively. In contrast, interaction with excimer laser radiation resulted an increase in the
contact angle to 1210. Such changes were identified as being due to: (i) the melting and partial
vitrification of the Al2O3/SiO2 based ceramic surface as a result of interaction with CO2,
Nd:YAG HPDL radiation. (ii) the surface roughness of the Al2O3/SiO2 based ceramic
increasing after interaction with excimer laser radiation. (iii) the surface oxygen content of the
Al2O3/SiO2 based ceramic increasing after interaction with CO2, Nd:YAG and HPDL radiation.
The work has shown that the wettability characteristics of the Al2O3/SiO2 based ceramic could
be controlled and/or modified with laser surface treatment. In particular, whether the laser
radiation had the propensity to cause surface melting. However, a wavelength dependance of
the change of the wetting properties could not be deduced from the findings of this work
Review of the Marine Monitoring Program (MMP)
The Marine Monitoring Program (MMP) monitors the condition of inshore water quality and aims to link this to changes in the health of key inshore environments (coral reefs and seagrass). This report provides a review of each of the 5 programs based on the best available information that was provided by the MMP providers at the time of the review
Removing Singularities
Big bang/crunch curvature singularities in exact CFT string backgrounds can
be removed by turning on gauge fields. This is described within a family of
{SL(2)xSU(2)xU(1)_x}/{U(1)xU(1)} quotient CFTs. Uncharged incoming
wavefunctions from the ``whiskers'' of the extended universe can be fully
reflected if and only if a big bang/crunch curvature singularity, from which
they are scattered, exists. Extended BTZ-like singularities remain as long as
U(1)_x is compact.Comment: 21 pages, harvma
On the instability of 3d null singularities
String propagation on a three-dimensional Lorentzian string orbifold with a
null singularity has been studied by Horowitz and Steif, and more recently by
Liu, Moore and Seiberg. We analyze the target space as a classical
gravitational background. The singularity becomes spacelike when an arbitrarily
small amount of matter is thrown at the singularity. This can be seen directly
by studying the null singularity as a limit of the M=0, J=0 BTZ black hole
metric.Comment: 9 pages, uses harvmac.tex. v2: minor wording changes in introduction,
fixed reference typo, new reference
Null Brane Intersections
We study pairs of planar D-branes intersecting on null hypersurfaces, and
other related configurations. These are supersymmetric and have finite energy
density. They provide open-string analogues of the parabolic orbifold and
null-fluxbrane backgrounds for closed superstrings. We derive the spectrum of
open strings, showing in particular that if the D-branes are shifted in a
spectator dimension so that they do not intersect, the open strings joining
them have no asymptotic states. As a result, a single non-BPS excitation can in
this case catalyze a condensation of massless modes, changing significantly the
underlying supersymmetric vacuum state. We argue that a similar phenomenon can
modify the null cosmological singularity of the time-dependent orbifolds. This
is a stringy mechanism, distinct from black-hole formation and other strong
gravitational instabilities, and one that should dominate at weak string
coupling. A by-product of our analysis is a new understanding of the appearance
of 1/4 BPS threshold bound states, at special points in the moduli space of
toroidally-compactified type-II string theory.Comment: Tex file, uses harvmac, 24 pages with 5 figures. Corrected typos and
added references. Final version to appear in JHE
Amplification of TLO Mediator Subunit Genes Facilitate Filamentous Growth in Candida Spp
Funding: This work was funded by the National Institutes of Allergy and Infectious Disease (AI113390, LCM) and the National Institutes of General Medical Sciences (GM62483, LCM). The funders had no role in study design, data collection and analysis, decision topublish, or preparation of the manuscript.Non peer reviewedPublisher PD
The period gene encodes a predominantly nuclear protein in adult Drosophila
The period gene of Drosophila melanogaster (per) is important for the generation and maintenance of biological rhythms. Previous light microscopic observations indicated that per is expressed in a variety of tissues and cell types and suggested that the per protein (PER) may be present in different subcellular compartments. To understand how PER influences circadian rhythms, it is important to define its subcellular location, especially in adult flies where inducible promoter experiments suggested that it is most relevant to circadian locomotor activity rhythms. To this end, we report the results of an immunoelectron microscopic analysis of wild-type flies and per-beta- galactosidase (beta-gal) fusion gene transgenics using a polyclonal anti-PER antibody or an anti-beta-gal antibody, respectively. Most of the PER antigen and the fusion gene product were located within nuclei, suggesting that PER acts in that subcellular compartment to affect circadian rhythms. The results are discussed in terms of per's possible biochemical functions
Bayesian Centroid Estimation for Motif Discovery
Biological sequences may contain patterns that are signal important
biomolecular functions; a classical example is regulation of gene expression by
transcription factors that bind to specific patterns in genomic promoter
regions. In motif discovery we are given a set of sequences that share a common
motif and aim to identify not only the motif composition, but also the binding
sites in each sequence of the set. We present a Bayesian model that is an
extended version of the model adopted by the Gibbs motif sampler, and propose a
new centroid estimator that arises from a refined and meaningful loss function
for binding site inference. We discuss the main advantages of centroid
estimation for motif discovery, including computational convenience, and how
its principled derivation offers further insights about the posterior
distribution of binding site configurations. We also illustrate, using
simulated and real datasets, that the centroid estimator can differ from the
maximum a posteriori estimator.Comment: 24 pages, 9 figure
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