1,089 research outputs found
A C0 interior penalty discontinuous Galerkin method for fourth‐order total variation flow I: Derivation of the method and numerical results
We consider the numerical solution of a fourth‐order total variation flow problem representing surface relaxation below the roughening temperature. Based on a regularization and scaling of the nonlinear fourth‐order parabolic equation, we perform an implicit discretization in time and a C0 Interior Penalty Discontinuous Galerkin (C0IPDG) discretization in space. The C0IPDG approximation can be derived from a mixed formulation involving numerical flux functions where an appropriate choice of the flux functions allows to eliminate the discrete dual variable. The fully discrete problem can be interpreted as a parameter dependent nonlinear system with the discrete time as a parameter. It is solved by a predictor corrector continuation strategy featuring an adaptive choice of the time step sizes. A documentation of numerical results is provided illustrating the performance of the C0IPDG method and the predictor corrector continuation strategy. The existence and uniqueness of a solution of the C0IPDG method will be shown in the second part of this paper
Quantum-number projection in the path-integral renormalization group method
We present a quantum-number projection technique which enables us to exactly
treat spin, momentum and other symmetries embedded in the Hubbard model. By
combining this projection technique, we extend the path-integral
renormalization group method to improve the efficiency of numerical
computations. By taking numerical calculations for the standard Hubbard model
and the Hubbard model with next nearest neighbor transfer, we show that the
present extended method can extremely enhance numerical accuracy and that it
can handle excited states, in addition to the ground state.Comment: 11 pages, 7 figures, submitted to Phys. Rev.
Stereotypes help people connect with others in the community: A situated functional analysis of the stereotype consistency bias in communication
Communicators tend to share more stereotype-consistent than stereotype-inconsistent information. The authors propose and test a situated functional model of this stereotype consistency bias: Stereotype-consistent and inconsistent information differentially serve 2 central functions of communication-sharing information and regulating relationships; depending on the communication context, information seen to serve these different functions better is more likely communicated. Results showed that stereotype-consistent information is perceived as more socially connective but less informative than inconsistent information, and when the stereotype is perceived to be highly shared in the community, more stereotype-consistent than inconsistent information is communicated due to its greater social connectivity function. These results highlight the need to examine communication as a dynamic and situated social activity. © 2007 American Psychological Association
A subdifferential formulation of fourth order singular diffusion equations
A fourth order equation with singular diffusivity, which is a model of relaxation dynamics for crystalline surfaces driven by surface diffusion, is formulated. The notion of subdifferentials enables us to formulate the singular diffusion equation mathematically as a gradient flow equation in the Sobolev space of negative power H-1. The subdifferential of the singular energy in H-1 is calculated. Moreover, the speed of a special profile is calculated for one dimensional problem. It turns out that a seemingly natural free boundary formulation with facets is inconsistent with a subdifferential formulation which can be approximated by a smooth energy
Enzootic bovine leukosis accompanied by splenomegaly in an 8-month-old calf
ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗIn this report, an 8-month-old calf (crossbred, Holstein × Japanese Black) developed fever and accompanied abomasum displacement. Blood chemical test showed remarkably high values of white blood cell count and heteromorphic lymphocytes. In pathological appraisal, enlarged splenomegaly and swelling of the lymph nodes were observed. Histopathological examination revealed invasion of tumor cells derived from B1 cells into systemic lymph nodes, liver and spleen. The provirus loads of bovine leukemia virus (BLV) was 1,439 copies per 10 ng DNA by using real time PCR. In conclusion, this case was diagnosed as bovine leukemia caused by BLV infection with a huge splenomegaly
Precise estimation of shell model energy by second order extrapolation method
A second order extrapolation method is presented for shell model
calculations, where shell model energies of truncated spaces are well described
as a function of energy variance by quadratic curves and exact shell model
energies can be obtained by the extrapolation. This new extrapolation can give
more precise energy than those of first order extrapolation method. It is also
clarified that first order extrapolation gives a lower limit of shell model
energy. In addition to the energy, we derive the second order extrapolation
formula for expectation values of other observables.Comment: PRC in pres
Ab initio Derivation of Low-energy Model for Iron-Based Superconductors LaFeAsO and LaFePO
Effective Hamiltonians for LaFeAsO and LaFePO are derived from the
downfolding scheme based on first-principles calculations and provide insights
for newly discovered superconductivity in the family of LnFeAsOF,
Ln = La, Ce, Pr, Nd, Sm, and Gd. Extended Hubbard Hamiltonians for five
maximally localized Wannier orbitals per Fe are constructed dominantly from
five-fold degenerate iron-3 bands. They contain parameters for effective
Coulomb and exchange interactions screened by the polarization of other
electrons away from the Fermi level. The onsite Coulomb interaction estimated
as 2.2-3.3 eV is compared with the transfer integrals between the
nearest-neighbor Fe-3 Wannier orbitals, 0.2-0.3 eV, indicating moderately
strong electron correlation. The Hund's rule coupling is found to be 0.3-0.6
eV. The derived model offers a firm basis for further studies on physics of
this family of materials. The effective models for As and P compounds turn out
to have very similar screened interactions with slightly narrower bandwidth for
the As compound.Comment: 5 pages, 3 figures, 1 table; to appear in J. Phys. Soc. Jpn. Vol. 77
No.9: Revised version contains corrected table values and discussions of
quantitative accuracy of constrained random-phase approximatio
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