7,203 research outputs found
Studying Double Charm Decays of B_{u,d} and B_{s} Mesons in the MSSM with R-parity Violation
Motivated by the possible large direct CP asymmetry of \bar{B}^0_d \to D^+
D^- decay measured by Belle collaboration, we investigate double charm B_{u,d}
and B_s decays in the minimal supersymmetric standard model with R-parity
violation. We derive the bounds on relevant R-parity violating couplings from
the current experimental data, which show quite consistent measurements among
relative collaborations. Using the constrained parameter spaces, we explore
R-parity violating effects on other observables in these decays, which have not
been measured or have not been well measured yet. We find that the R-parity
violating effects on the mixing-induced CP asymmetries of \bar{B}^0_d \to
D^{(*)+} D^{(*)-} and \bar{B}^0_s \to D^{(*)+}_s D^{(*)-}_s decays could be
very large, nevertheless the R-parity violating effects on the direct CP
asymmetries could not be large enough to explain the large direct CP violation
of \bar{B}^0_d \to D^{+} D^{-} from Belle. Our results could be used to probe
R-parity violating effects and will correlate with searches for direct R-parity
violating signals in future experiments.Comment: 28 pages and 6 figures, matches published versio
Expression of Green Fluorescence Protein (GFP) in Zebrafish Muscle through Injection: A Gene Therapy Model
Expression of the target gene is important for gene therapy. Presently, localized transgenesis is used for gene therapy which can be achieved by a target gene expression. Here, we have reported the plasmid mediated gene therapy to zebrafish model. For this purpose, we have chosen green fluorescent protein (GFP) as a target gene because the expression can be detected easily. GFP was inserted in a plasmid vector, pQE30 to develop the vector pQE30GFP. The plasmid pQE30GFP was constructed form plasmid, pQE30 and pEGFPC2. pQE30GFP injected directly in one group of fish into the muscle where luciferase expression was noted. In another group, after injection electroporation was performed where we have also noted luciferase expression; but, electroporation cause muscle injury to the zebrafish. In our case, the expression was very strong at the site of injection in first group in compare to electroporation group and in both the cases expression was stable more than two weeks
Enhancement factor distribution around a single SERS Hot-spot and its relation to Single Molecule detection
We provide the theoretical framework to understand the phenomenology and
statistics of single-molecule (SM) signals arising in Surface-Enhanced Raman
Scattering (SERS) under the presence of so-called electromagnetic hot-spots
(HS's). We show that most characteristics of the SM-SERS phenomenon can be
tracked down to the presence of tail-like (power law) distribution of
enhancements and we propose a specific model for it. We analyze, in the light
of this, the phenomenology of SM-SERS and show how the different experimental
manifestations of the effect reported in the literature can be analyzed and
understood under a unified ``universal'' framework with a minimum set of
parameters.Comment: 13 pages, 4 figures, submitted to J. Chem. Phy
Ab initio Studies of the Possible Magnetism in BN Sheet by Non-magnetic Impurities and Vacancies
We performed first-principles calculations to investigate the possible
magnetism induced by the different concentrations of non-magnetic impurities
and vacancies in BN sheet. The atoms of Be, B, C, N, O, Al and Si are used to
replace either B or N in the systems as impurities. We discussed the changes in
density of states as well as the extent of the spatial distributions of the
defect states, the possible formation of magnetic moments, the magnitude of the
magnetization energies and finally the exchange energies due to the presence of
these defects. It is shown that the magnetization energies tend to increase as
the concentrations of the defects decreases in most of the defect systems which
implies a definite preference of finite magnetic moments. The calculated
exchange energies are in general tiny but not completely insignificant for two
of the studied defect systems, i.e. one with O impurities for N and the other
with B vacancies.Comment: 8 pages, 10 figures, submitted to Phys. Rev.
Non-Abelian vortices in the emergent U(2) gauge theory of the Hubbard model
By the spin-fermion formula, the Hubbard model on the honeycomb lattice is
represented by a U(2) gauge theory in the mean field method, non-Abelian vortex
solutions are constructed based on this theory. The quantization condition
shows that the magnetic flux quanta are half-integer. There are bosonic
zero modes for winding vortices. For the fermions, there are 2 zero energy
states (ZESs) corresponding to the single elementary vortex. In the vortex core
and on the edge, the system are in the semi-metal phase with a spin gap and in
the insulator phase with N\'eel order phase, and can be mapped to the
superconductor in class A and CI, respectively.Comment: 4pages, 2table
Recognizing Customer Knowledge Level towards Products for Recommendation in Electronic Commerce
A powerful online recommendation system in Electronic Commerce (EC) must know its targeted customers well and employ effective marketing strategies. Market research is a very important way to know the customers well. For high-tech products with great variety such as computers, cellular phones, and digital cameras, customers’ knowledge level towards products may have a decisive influence on their purchase decision. While many online recommendation systems focus on utilizing data mining techniques in user profile and transaction data, this paper presents a method for recognizing customer knowledge level as a preprocess for more effective online recommendation in EC. The method consists of two Back Propagation Networks (BPN) and predicts based on customer characteristics and online navigation behaviors. A simple simulated digital camera EC store case study was conducted and the good preliminary result implies the good potential of the proposed method
Numerical simulation of Quasi-Normal Modes in time-dependent background
We study the massless scalar wave propagation in the time-dependent
Schwarzschild black hole background. We find that the Kruskal coordinate is an
appropriate framework to investigate the time-dependent spacetime. A
time-dependent scattering potential is derived by considering dynamical black
hole with parameters changing with time. It is shown that in the quasinormal
ringing both the decay time-scale and oscillation are modified in the
time-dependent background.Comment: 10 pages, 8 figures; reference adde
Density Fluctuation Effects on Collective Neutrino Oscillations in O-Ne-Mg Core-Collapse Supernovae
We investigate the effect of matter density fluctuations on supernova
collective neutrino flavor oscillations. In particular, we use full
multi-angle, 3-flavor, self-consistent simulations of the evolution of the
neutrino flavor field in the envelope of an O-Ne-Mg core collapse supernova at
shock break-out (neutrino neutronization burst) to study the effect of the
matter density "bump" left by the He-burning shell. We find a seemingly
counterintuitive increase in the overall electron neutrino survival probability
created by this matter density feature. We discuss this behavior in terms of
the interplay between the matter density profile and neutrino collective
effects. While our results give new insights into this interplay, they also
suggest an immediate consequence for supernova neutrino burst detection: it
will be difficult to use a burst signal to extract information on fossil
burning shells or other fluctuations of this scale in the matter density
profile. Consistent with previous studies, our results also show that the
interplay of neutrino self-coupling and matter fluctuation could cause a
significant increase in the electron neutrino survival probability at very low
energyComment: 12 pages, 11 figures. This is a pre-submission version of the pape
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