1,576 research outputs found
The classification of all single travelling wave solutions to Calogero-Degasperis-Focas equation
Under the travelling wave transformation, Calogero-Degasperis-Focas equation
was reduced to an ordinary differential equation. Using a symmetry group of
one-parameter, this ODE was reduced to a second order linear inhomogeneous ODE.
Furthermore, we applied the change of the variable and complete discrimination
system for polynomial to solve the corresponding integrals and obtained the
classification of all single travelling wave solutions to
Calogero-Degasperis-Focas equation.Comment: 9 page
Unitarization of Total Cross Section and Coherent Effect in pQCD
A formula to unitarize the leading-log BFKL-Pomeron amplitude is derived
using a coherent property of two-body collision in the peripheral region. This
procedure also allows an algebraic characterization of the Reggeon in QCD based
on color, instead of the total angular momentum of the gluons being exchanged.Comment: Talk given at the DIS99 Meeting in Zeuthen, Germany. April, 1999. 3
page
The Unique Effect of Depreciation on Earnings Properties: Persistence and Value Relevance of Earnings
Prior studies document high persistence of earnings is a desirable earningsâ attribute and associated with high value relevance of earnings. Nevertheless, other studies indicate negative earnings components depress persistence of earnings. Depreciation expense constitutes a major negative earnings component for most firms. Larger depreciation could represent higher cost of utilizing resources; however, it could also represent a higher level of capital improvements and conservative accounting choice. We find firms reporting higher depreciation and amortization expense (High DP) outperform other firms (Low DP) in terms of future operating cash flows. Though the persistence of earnings is lower for High DP firms, the stock markets actually place higher valuation weight of their earnings. Our study contributes to research on earnings attributes and the role of accounting information in the stock markets. We identify potential biases of overly reliance on the persistence of earnings to evaluate a firmâs performance and to predict the stock market reactions
Unitarized Diffractive Scattering in QCD and Application to Virtual Photon Total Cross Sections
The problem of restoring Froissart bound to the BFKL-Pomeron is studied in an
extended leading-log approximation of QCD. We consider parton-parton scattering
amplitude and show that the sum of all Feynman-diagram contributions can be
written in an eikonal form. In this form dynamics is determined by the phase
shift, and subleading-logs of all orders needed to restore the Froissart bound
are automatically provided. The main technical difficulty is to find a way to
extract these subleading contributions without having to compute each Feynman
diagram beyond the leading order. We solve that problem by using nonabelian cut
diagrams introduced elsewhere. They can be considered as colour filters used to
isolate the multi-Reggeon contributions that supply these subleading-log terms.
Illustration of the formalism is given for amplitudes and phase shifts up to
three loops. For diffractive scattering, only phase shifts governed by one and
two Reggeon exchanges are needed. They can be computed from the
leading-log-Reggeon and the BFKL-Pomeron amplitudes. In applications, we argue
that the dependence of the energy-growth exponent on virtuality for
total cross section observed at HERA can be interpreted as the
first sign of a slowdown of energy growth towards satisfying the Froissart
bound. An attempt to understand these exponents with the present formalism is
discussed.Comment: 41 pages in revtex preprint format, with 10 figure
Singlet-triplet transitions in highly correlated nanowire quantum dots
We consider a quantum dot embedded in a three-dimensional nanowire with
tunable aspect ratio a. A configuration interaction theory is developed to
calculate the energy spectra of the finite 1D quantum dot systems charged with
two electrons in the presence of magnetic fields B along the wire axis.
Fruitful singlet-triplet transition behaviors are revealed and explained in
terms of the competing exchange interaction, correlation interaction, and spin
Zeeman energy. In the high aspect ratio regime, the singlet-triplet transitions
are shown designable by tuning the parameters a and B. The transitions also
manifest the highly correlated nature of long nanowire quantum dots.Comment: 4 pages, 4 figure
A Multiple Commutator Formula for the Sum of Feynman Diagrams
In the presence of a large parameter, such as mass or energy, leading
behavior of individual Feynman diagrams often get cancelled in the sum. This is
known to happen in large- QCD in the presence of a baryon, and also in the
case of high-energy electron-electron as well as quark-quark scatterings. We
present an exact combinatorial formula, involving multiple commutators of the
vertices, which can be used to compute such cancellations. It is a non-abelian
generalization of the eikonal formula, and will be applied in subsequent
publications to study the consistency of large- QCD involving baryons, as
well as high-energy quark-quark scattering in ordinary QCD.Comment: uu-encoded latex file with two postscript figure
Quantitative evaluation of motor function before and after engraftment of dopaminergic neurons in a rat model of Parkinson's disease
Although gait change is considered a useful indicator of severity in animal models of Parkinson's disease, systematic and extensive gait analysis in animal models of neurological deficits is not well established. The CatWalk-assisted automated gait analysis system provides a comprehensive way to assess a number of dynamic and static gait parameters simultaneously. In this study, we used the Catwalk system to investigate changes in gait parameters in adult rats with unilateral 6-OHDA-induced lesions and the rescue effect of dopaminergic neuron transplantation on gait function. Four weeks after 6-OHDA injection, the intensity and maximal area of contact were significantly decreased in the affected paws and the swing speed significantly decreased in all four paws. The relative distance between the hind paws also increased, suggesting that animals with unilateral 6-OHDA-induced lesions required all four paws to compensate for loss of balance function. At 8 weeks post-transplantation, engrafted dopaminergic neurons expressed tyrosine hydroxylase. In addition, the intensity, contact area, and swing speed of the four limbs increased and the distance between the hind paws decreased. Partial recovery of methamphetamine-induced rotational response was also noted
Hadronic Charmed Meson Decays Involving Tensor Mesons
Charmed meson decays into a pseudoscalar meson P and a tensor meson T are
studied. The charm to tensor meson transition form factors are evaluated in the
Isgur-Scora-Grinstein-Wise (ISGW) quark model. It is shown that the
Cabibbo-allowed decay is dominated by the
W-annihilation contribution and has the largest branching ratio in
decays. We argue that the Cabibbo-suppressed mode
should be suppressed by one order of magnitude relative to . When the finite width effect of the tensor resonances is taken
into account, the decay rate of is generally enhanced by a factor of
. Except for , the predicted branching ratios
of decays are in general too small by one to two orders of magnitude
compared to experiment. However, it is very unlikely that the
transition form factors can be enhanced by a factor of within the
ISGW quark model to account for the discrepancy between theory and experiment.
As many of the current data are still preliminary and lack sufficient statistic
significance, more accurate measurements are needed to pin down the issue.Comment: 11 page
Did Information Amount Matter in Framing Effect?
Framing the product attribute(s) in either positive or negative way can result in different responses. This phenomenon is referred to attribute framing effect. This article reported results from a laboratory experiment which examines the influence of message framing and information amounts on Internet buyersâ judgments. The amount of information was defined in terms of the number of attribute information of the target product. The result indicated significant framing effects no matter how much attribute information was presented. Positive information leads to more favorable responses than negative information. In addition, respondents who were exposed to more amounts of positive information showed more favorable evaluations than those who were exposed to less amounts of positive information condition. However, more amounts of negative information did not result in less favorable responses
Decays in R-parity violating supersymmetry
In light of the recent experimental data from factories, We try to
explain the large branching ratio (compared to the Standard Model prediction)
of the decay in the context of R-parity violating
(\rpv) supersymmetry. We investigate other observed modes
and find that only two pairs of \rpv coupling can satisfy the requirements
without affecting the other and decay modes except the
mode . We also calculate the CP asymmetry for the observed decay
modes affected by the new couplings.Comment: 3 pages, 1 figure, Proceedings of the Fifth KEK Topical Conferenc
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