61,741 research outputs found
Pulsar Velocity with Three-Neutrino Oscillations in Non-adiabatic Processes
We have studied the position dependence of neutrino energy on the
Kusenko-Segr\`{e} mechanism as an explanation of the proper motion of pulsars.
The mechanism is also examined in three-generation mixing of neutrinos and in a
non-adiabatic case. The position dependence of neutrino energy requires the
higher value of magnetic field such as Gauss in order
to explain the observed proper motion of pulsars. It is shown that possible
non-adiabatic processes decrease the neutrino momentum asymmetry, whereas an
excess of electron neutrino flux over other flavor neutrino fluxes increases
the neutrino momentum asymmetry. It is also shown that a general treatment with
all three neutrinos does not modify the result of the two generation treatment
if the standard neutrino mass hierarchy is assumed.Comment: 8 pages, REVTEX, no figure
Business integration models in the context of web services.
E-commerce development and applications have
been bringing the Internet to business and marketing
and reforming our current business styles and
processes. The rapid development of the Web, in
particular, the introduction of the semantic web and
web service technologies, enables business
processes, modeling and management to enter an
entirely new stage. Traditional web based business
data and transactions can now be analyzed,
extracted and modeled to discover new business
rules and to form new business strategies, let alone
mining the business data in order to classify
customers or products. In this paper, we investigate
and analyze the business integration models in the
context of web services using a micro-payment
system because a micro-payment system is
considered to be a service intensive activity, where
many payment tasks involve different forms of
services, such as payment method selection for
buyers, security support software, product price
comparison, etc. We will use the micro-payment case
to discuss and illustrate how the web services
approaches support and transform the business
process and integration model.
Viscosity from elliptic flow: the path to precision
Using viscous relativistic hydrodynamics we show that systematic studies of
the impact parameter dependence of the eccentricity scaled elliptic flow can
distinguish between different models for the calculation of the initial source
eccentricity. This removes the largest present uncertainty in the extraction of
the specific viscosity of the matter created in relativistic heavy-ion
collisions from precise elliptic flow measurements.Comment: 4 pages, incl. 4 figure
The geometrically-averaged density of states as a measure of localization
Motivated by current interest in disordered systems of interacting electrons,
the effectiveness of the geometrically averaged density of states,
, as an order parameter for the Anderson transition is
examined. In the context of finite-size systems we examine complications which
arise from finite energy resolution. Furthermore we demonstrate that even in
infinite systems a decline in with increasing disorder
strength is not uniquely associated with localization.Comment: 8 pages, 8 figures; revised text and figure
Unusual Tunneling Characteristics of Double-quantum-well Heterostructures
We report tunneling phenomena in double InGaAs quantum-well
structures that are at odds with the conventional parallel-momentum-conserving
picture of tunneling between two-dimensional systems. We found that the
tunneling current was mostly determined by the correlation between the emitter
and the state in one well, and not by that between those in both wells. Clear
magnetic-field-dependent features were first observed before the main
resonance, corresponding to tunneling channels into the Landau levels of the
well near the emitter. These facts provide evidence of the violation of
in-plane momentum conservation in two-dimensional systems.Comment: Submitted to ICPS-27 conference proceeding as a contributed pape
Screen key genes associated with distraction-induced osteogenesis of stem cells using bioinformatics methods
Background: Applying mesenchymal stem cells (MSCs), together with the distraction osteogenesis (DO) process, displayed enhanced bone quality and shorter treatment periods. The DO guides the differentiation of MSCs by providing mechanical clues. However, the underlying key genes and pathways are largely unknown. The aim of this study was to screen and identify hub genes involved in distraction-induced osteogenesis of MSCs and potential molecular mechanisms.
Material and Methods: The datasets were downloaded from the ArrayExpress database. Three samples of negative control and two samples subjected to 5% cyclic sinusoidal distraction at 0.25 Hz for 6 h were selected for screening differentially expressed genes (DEGs) and then analysed via bioinformatics methods. The Gene Ontology (GO) terms and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment were investigated. The protein–protein interaction (PPI) network was visualised through the Cytoscape software. Gene set enrichment analysis (GSEA) was conducted to verify the enrichment of a self-defined osteogenic gene sets collection and identify osteogenic hub genes.
Results: Three hub genes (IL6, MMP2, and EP300) that were highly associated with distraction-induced osteogenesis of MSCs were identified via the Venn diagram. These hub genes could provide a new understanding of distraction-induced osteogenic differentiation of MSCs and serve as potential gene targets for optimising DO via targeted therapies
Drastic Reduction of Shot Noise in Semiconductor Superlattices
We have found experimentally that the shot noise of the tunneling current
through an undoped semiconductor superlattice is reduced with respect to the
Poissonian noise value , and that the noise approaches 1/3 of that value
in superlattices whose quantum wells are strongly coupled. On the other hand,
when the coupling is weak or when a strong electric field is applied to the
superlattice the noise becomes Poissonian. Although our results are
qualitatively consistent with existing theories for one-dimensional mulitple
barriers, the theories cannot account for the dependence of the noise on
superlattice parameters that we have observed.Comment: 4 Pages, 3Figure
- …