35,180 research outputs found
Natural law, natural philosophy, natural rights
Who or what is the creator (and how is that we can presume to read his mind and know his intentions) and how do we know there are inalienable rights? As will become clear in the pages below, the idea of the creator is a powerful concept that permeates western thought from at least the period of ancient Greeks to Jefferson\u27s day. In fact, it is the confluence of ancient pagan philosophy (here represented by Cicero)and seventeenth century science, with only a dollop of Christian thought, that combines to create the ideas so fundamental to the American civil experience
Something Wicked this Way Comes: Constitutional Transformation and the Growing Power of the Supreme Court
Immersed Boundary Smooth Extension: A high-order method for solving PDE on arbitrary smooth domains using Fourier spectral methods
The Immersed Boundary method is a simple, efficient, and robust numerical
scheme for solving PDE in general domains, yet it only achieves first-order
spatial accuracy near embedded boundaries. In this paper, we introduce a new
high-order numerical method which we call the Immersed Boundary Smooth
Extension (IBSE) method. The IBSE method achieves high-order accuracy by
smoothly extending the unknown solution of the PDE from a given smooth domain
to a larger computational domain, enabling the use of simple Cartesian-grid
discretizations (e.g. Fourier spectral methods). The method preserves much of
the flexibility and robustness of the original IB method. In particular, it
requires minimal geometric information to describe the boundary and relies only
on convolution with regularized delta-functions to communicate information
between the computational grid and the boundary. We present a fast algorithm
for solving elliptic equations, which forms the basis for simple, high-order
implicit-time methods for parabolic PDE and implicit-explicit methods for
related nonlinear PDE. We apply the IBSE method to solve the Poisson, heat,
Burgers', and Fitzhugh-Nagumo equations, and demonstrate fourth-order pointwise
convergence for Dirichlet problems and third-order pointwise convergence for
Neumann problems
OPE analysis of the nucleon scattering tensor including weak interaction and finite mass effects
We perform a systematic operator product expansion of the most general form
of the nucleon scattering tensor including electro-magnetic and
weak interaction processes. Finite quark masses are taken into account and a
number of higher-twist corrections are included. In this way we derive
relations between the lowest moments of all 14 structure functions and matrix
elements of local operators. Besides reproducing well-known results, new sum
rules for parity-violating polarized structure functions and new mass
correction terms are obtained.Comment: 50 pages, additional references adde
Identification of gravity waves in hydrodynamical simulations
The excitation of internal gravity waves by an entropy bubble oscillating in
an isothermal atmosphere is investigated using direct two-dimensional numerical
simulations. The oscillation field is measured by a projection of the simulated
velocity field onto the anelastic solutions of the linear eigenvalue problem
for the perturbations. This facilitates a quantitative study of both the
spectrum and the amplitudes of excited g-modes.Comment: 12 pages, 11 figures, Appendices only available onlin
Magnetic correlations of the quasi-one-dimensional half-integer spin-chain antiferromagnets SrVO ( = Co, Mn)
Magnetic correlations of two iso-structural quasi-one-dimensional (1D)
antiferromagnetic spin-chain compounds SrVO ( = Co, Mn) have
been investigated by magnetization and powder neutron diffraction. Two
different collinear antiferromagnetic (AFM) structures, characterized by the
propagation vectors, = (0 0 1) and = (0 0 0), have been found below
5.2 K and 42.2 K for the Co- and Mn-compounds, respectively. For
the Mn-compound, AFM chains (along the axis) order ferromagnetically within
the plane, whereas, for the Co-compound, AFM chains order
ferro-/antiferromagnetically along the direction. The critical exponent
study confirms that the Co- and Mn-compounds belong to the Ising and Heisenberg
universality classes, respectively. For both compounds, short-range spin-spin
correlations are present over a wide temperature range above . The reduced
ordered moments at base temperature (1.5 K) indicate the presence of quantum
fluctuations in both compounds due to the quasi-1D magnetic interactions.Comment: 14 pages, 10 figures, 9 table
- …