4,800 research outputs found
The Notostigmata, a new suborder of Acari
The following studies on this new suborder have been made on material included in the famous French Arachnologist E. Simon's rich collection and lent by him to Drs. H. J. Hansen and W. Sørensen. ..
A magistrate's view on achieving compliance
This conference presentation was given as part of the Achieving Compliance with Road Traffic Law: What can enforcement, prosecution and sentencing contribute? Conference by Chris Hunt Cooke, Magistrate and Chairman of the Magistrates' Association Road Traffic Committee. The conference, jointly organised by PACTS and the Criminal Justice Research Centre with Brunel Law School, was hosted at Brunel University on the 13th June 2012, and was the first opportunity to review the evidence about how to improve compliance with road traffic law. Its aim was to set out the challenges facing the government over the next few years and the steps that need to be taken to improve levels of compliance on our roads. It took a wide look at the process of compliance from initial choices about enforcement through to the effectiveness of the court system
Spectroscopy of Hadrons with b Quarks from Lattice NRQCD
Preliminary results from an extensive lattice calculation of the B, B_c, and
\Upsilon spectrum at quenched \beta = 6.0 are presented. The study includes
radially and orbitally excited mesons, and baryons containing b quarks. The b
quarks are formulated using NRQCD; for light and c quarks, a tadpole-improved
clover action is used.Comment: talk given at LATTICE98(heavyqk), 3 pages LaTeX, 2 Postscript figure
The scaling dimension of low lying Dirac eigenmodes and of the topological charge density
As a quantitative measure of localization, the inverse participation ratio of
low lying Dirac eigenmodes and topological charge density is calculated on
quenched lattices over a wide range of lattice spacings and volumes. Since
different topological objects (instantons, vortices, monopoles, and artifacts)
have different co-dimension, scaling analysis provides information on the
amount of each present and their correlation with the localization of low lying
eigenmodes.Comment: Lattice2004(topology), Fermilab, June 21 - 26, 2004; 3 pages, 3
figure
An apprach to generate large and small leptonic mixing angles
We take up the point of view that Yukawa couplings can be either 0 or 1, and
the mass patterns of fermions are generated purely from the structure of the
Yukawa matrices. We utilize such neutrino as well as charged leptonic textures
which lead to (maximal) mixing angles of in each sector for relevant
transitions. The combined leptonic CKM mixing angles are
which lead to very small relevant to solar neutrino and LSND
experiments. We propose that on the other hand the absence of the charged
leptonic partner of the sterile neutrino maintains the angle from the
neutrino sector for the transition and hence
atmospheric neutrino anomaly is explained through maximal mixing
Canonical General Relativity on a Null Surface with Coordinate and Gauge Fixing
We use the canonical formalism developed together with David Robinson to st=
udy the Einstein equations on a null surface. Coordinate and gauge conditions =
are introduced to fix the triad and the coordinates on the null surface. Toget=
her with the previously found constraints, these form a sufficient number of
second class constraints so that the phase space is reduced to one pair of
canonically conjugate variables: \Ac_2\and\Sc^2. The formalism is related to
both the Bondi-Sachs and the Newman-Penrose methods of studying the
gravitational field at null infinity. Asymptotic solutions in the vicinity of
null infinity which exclude logarithmic behavior require the connection to fall
off like after the Minkowski limit. This, of course, gives the previous
results of Bondi-Sachs and Newman-Penrose. Introducing terms which fall off
more slowly leads to logarithmic behavior which leaves null infinity intact,
allows for meaningful gravitational radiation, but the peeling theorem does not
extend to in the terminology of Newman-Penrose. The conclusions are in
agreement with those of Chrusciel, MacCallum, and Singleton. This work was
begun as a preliminary study of a reduced phase space for quantization of
general relativity.Comment: magnification set; pagination improved; 20 pages, plain te
Generalized stochastic Schroedinger equations for state vector collapse
A number of authors have proposed stochastic versions of the Schr\"odinger
equation, either as effective evolution equations for open quantum systems or
as alternative theories with an intrinsic collapse mechanism. We discuss here
two directions for generalization of these equations. First, we study a general
class of norm preserving stochastic evolution equations, and show that even
after making several specializations, there is an infinity of possible
stochastic Schr\"odinger equations for which state vector collapse is provable.
Second, we explore the problem of formulating a relativistic stochastic
Schr\"odinger equation, using a manifestly covariant equation for a quantum
field system based on the interaction picture of Tomonaga and Schwinger. The
stochastic noise term in this equation can couple to any local scalar density
that commutes with the interaction energy density, and leads to collapse onto
spatially localized eigenstates. However, as found in a similar model by
Pearle, the equation predicts an infinite rate of energy nonconservation
proportional to , arising from the local double commutator in
the drift term.Comment: 24 pages Plain TeX. Minor changes, some new references. To appear in
Journal of Physics
Fourth order indirect integration method for black hole perturbations: even modes
On the basis of a recently proposed strategy of finite element integration in
time domain for partial differential equations with a singular source term, we
present a fourth order algorithm for non-rotating black hole perturbations in
the Regge-Wheeler gauge. Herein, we address even perturbations induced by a
particle plunging in. The forward time value at the upper node of the
grid cell is obtained by an algebraic sum of i) the preceding node values of
the same cell, ii) analytic expressions, related to the jump conditions on the
wave function and its derivatives, iii) the values of the wave function at
adjacent cells. In this approach, the numerical integration does not deal with
the source and potential terms directly, for cells crossed by the particle
world line. This scheme has also been applied to circular and eccentric orbits
and it will be object of a forthcoming publication.Comment: This series of papers deals with EMRI for LISA. With the respect to
the v1 version, the algorithm has been improved; convergence tests and
references have been added; v2 is composed by 23 pages, and 6 figures. Paper
accepted by Class. Quantum Gravity for the special issue on Theory Meets Data
Analysis at Comparable and Extreme Mass Ratios (Capra and NRDA) at Perimeier
Institute in June 201
- …
