1,104 research outputs found
Testing pitch recognition to improve talent identification and player development
The goal of this paper is to investigate the usefulness of video-occlusion testing of batters’ pitch recognition skills in professional baseball organizations. A highly valued perceptual attribute of modern batters, pitch recognition can be measured without batters amassing hundreds of plate appearances. Pitch Recognition testing, triangulated with analytics, can improve player evaluation, development, and even opponent preparation at the major league level. This paper merges decades of sport science research using video-occlusion methods with recent “micro-studies” applying video-occlusion testing of pitch recognition in minor league baseball, college baseball, and the Cape Cod Baseball League in order to address issues germane to the field testing that widespread implementation requires
Cosmic ray composition at high energies: Results from the TRACER project
The TRACER instrument Transition Radiation Array for Cosmic Energetic
Radiation is designed to measure the individual energy spectra of cosmic-ray
nuclei in long-duration balloon flights The large geometric factor of TRACER 5
m 2 sr permits statistically significant measurements at particle energies well
beyond 10 14 eV TRACER identifies individual cosmic-ray nuclei with
single-element resolution and measures their energy over a very wide range from
about 0 5 to 10 000 GeV nucleon This is accomplished with a gas detector system
of 1600 single-wire proportional tubes and plastic fiber radiators that measure
specific ionization and transition radiation signals combined with plastic
scintillators and acrylic Cherenkov counters A two-week flight in Antarctica in
December 2003 has led to a measurement of the nuclear species oxygen to iron O
Ne Mg Si S Ar Ca and Fe up to about 3 000 GeV nucleon We shall present the
energy spectra and relative abundances for these elements and discuss the
implication of the results in the context of current models of acceleration and
propagation of galactic cosmic rays The instrument has been refurbished for a
second long-duration flight in the Northern hemisphere scheduled for summer
2006 For this flight the dynamic range of TRACER has been extended to permit
inclusion of the lighter elements B C and N in the measurement.Comment: 36th COSPAR Scientific Assembly. Held 16 - 23 July 2006, in Beijing,
China., p.251
An Effective Lagrangian with Broken Scale and Chiral Symmetry IV: Nucleons and Mesons at Finite Temperature
We study the finite temperature properties of an effective chiral Lagrangian
which describes nuclear matter. Thermal fluctuations in both the nucleon and
the meson fields are considered. The logarithmic and square root terms in the
effective potential are evaluated by expansion and resummation with the result
written in terms of the exponential integral and the error function,
respectively. In the absence of explicit chiral symmetry breaking a phase
transition restores the symmetry, but when the pion has a mass the transition
is smooth. The nucleon and meson masses as a functions of density and
temperature are discussed.Comment: 21 pages LaTeX + 11 postscript figures, uses epsf.st
A new photon recoil experiment: towards a determination of the fine structure constant
We report on progress towards a measurement of the fine structure constant to
an accuracy of or better by measuring the ratio of the
Planck constant to the mass of the cesium atom. Compared to similar
experiments, ours is improved in three significant ways: (i) simultaneous
conjugate interferometers, (ii) multi-photon Bragg diffraction between same
internal states, and (iii) an about 1000 fold reduction of laser phase noise to
-138 dBc/Hz. Combining that with a new method to simultaneously stabilize the
phases of four frequencies, we achieve 0.2 mrad effective phase noise at the
location of the atoms. In addition, we use active stabilization to suppress
systematic effects due to beam misalignment.Comment: 12 pages, 9 figure
Ground state properties of heavy alkali halides
We extend previous work on alkali halides by calculations for the heavy-atom
species RbF, RbCl, LiBr, NaBr, KBr, RbBr, LiI, NaI, KI, and RbI. Relativistic
effects are included by means of energy-consistent pseudopotentials,
correlations are treated at the coupled-cluster level. A striking deficiency of
the Hartree-Fock approach are lattice constants deviating by up to 7.5 % from
experimental values which is reduced to a maximum error of 2.4 % by taking into
account electron correlation. Besides, we provide ab-initio data for in-crystal
polarizabilities and van der Waals coefficients.Comment: accepted by Phys. Rev.
Correlation effects in ionic crystals: I. The cohesive energy of MgO
High-level quantum-chemical calculations, using the coupled-cluster approach
and extended one-particle basis sets, have been performed for (Mg2+)n (O2-)m
clusters embedded in a Madelung potential. The results of these calculations
are used for setting up an incremental expansion for the correlation energy of
bulk MgO. This way, 96% of the experimental cohesive energy of the MgO crystal
is recovered. It is shown that only 60% of the correlation contribution to the
cohesive energy is of intra-ionic origin, the remaining part being caused by
van der Waals-like inter-ionic excitations.Comment: LaTeX, 20 pages, no figure
In Vitro Evaluation of Spider Silk Meshes as a Potential Biomaterial for Bladder Reconstruction
Reconstruction of the bladder by means of both natural and synthetic materials remains a challenge due to severe adverse effects such as mechanical failure. Here we investigate the application of spider major ampullate gland-derived dragline silk from the Nephila edulis spider, a natural biomaterial with outstanding mechanical properties and a slow degradation rate, as a potential scaffold for bladder reconstruction by studying the cellular response of primary bladder cells to this biomaterial. We demonstrate that spider silk without any additional biological coating supports adhesion and growth of primary human urothelial cells (HUCs), which are multipotent bladder cells able to differentiate into the various epithelial layers of the bladder. HUCs cultured on spider silk did not show significant changes in the expression of various epithelial-to-mesenchymal transition and fibrosis associated genes, and demonstrated only slight reduction in the expression of adhesion and cellular differentiation genes. Furthermore, flow cytometric analysis showed that most of the silk-exposed HUCs maintain an undifferentiated immunophenotype. These results demonstrate that spider silk from the Nephila edulis spider supports adhesion, survival and growth of HUCs without significantly altering their cellular properties making this type of material a suitable candidate for being tested in pre-clinical models for bladder reconstruction
Isovector and isoscalar superfluid phases in rotating nuclei
The subtle interplay between the two nuclear superfluids, isovector T=1 and
isoscalar T=0 phases, are investigated in an exactly soluble model. It is shown
that T=1 and T=0 pair-modes decouple in the exact calculations with the T=1
pair-energy being independent of the T=0 pair-strength and vice-versa. In the
rotating-field, the isoscalar correlations remain constant in contrast to the
well known quenching of isovector pairing. An increase of the isoscalar (J=1,
T=0) pair-field results in a delay of the bandcrossing frequency. This
behaviour is shown to be present only near the N=Z line and its experimental
confirmation would imply a strong signature for isoscalar pairing collectivity.
The solutions of the exact model are also discussed in the
Hartree-Fock-Bogoliubov approximation.Comment: 5 pages, 4 figures, submitted to PR
Scale-free static and dynamical correlations in melts of monodisperse and Flory-distributed homopolymers: A review of recent bond-fluctuation model studies
It has been assumed until very recently that all long-range correlations are
screened in three-dimensional melts of linear homopolymers on distances beyond
the correlation length characterizing the decay of the density
fluctuations. Summarizing simulation results obtained by means of a variant of
the bond-fluctuation model with finite monomer excluded volume interactions and
topology violating local and global Monte Carlo moves, we show that due to an
interplay of the chain connectivity and the incompressibility constraint, both
static and dynamical correlations arise on distances . These
correlations are scale-free and, surprisingly, do not depend explicitly on the
compressibility of the solution. Both monodisperse and (essentially)
Flory-distributed equilibrium polymers are considered.Comment: 60 pages, 49 figure
Current-sheet formation in incompressible electron magnetohydrodynamics
The nonlinear dynamics of axisymmetric, as well as helical, frozen-in vortex
structures is investigated by the Hamiltonian method in the framework of ideal
incompressible electron magnetohydrodynamics. For description of current-sheet
formation from a smooth initial magnetic field, local and nonlocal nonlinear
approximations are introduced and partially analyzed that are generalizations
of the previously known exactly solvable local model neglecting electron
inertia. Finally, estimations are made that predict finite-time singularity
formation for a class of hydrodynamic models intermediate between that local
model and the Eulerian hydrodynamics.Comment: REVTEX4, 5 pages, no figures. Introduction rewritten, new material
and references adde
- …