5,046 research outputs found
The Hormone Conflict Between the EEC and the United States Within the Context of GATT
For many years, consumer organizations within the European Community have demanded the prohibition of natural and synthetic hormones from use in animal fodder. Since the level of hormone use by breeders varies among Member States, demands for a hormone prohibition have also differed in intensity from State to State. After lengthy negotiations beset with legal difficulties, a general, community-wide prohibition became reality at the beginning of 1989. The price of this policy has been trade difficulties with the United States which, up to the present time,\u27 have resulted in trade sanctions and economic losses on both sides. Since both parties have agreed to resolve future economic differences in a more rational manner, General Agreement of Tariffs and Trade ( GATT ) related questions of international law that surfaced and were championed by both sides must be examined to clarify the role of the law in such cases. The following discussion will deal with these relevant issues
Anisotropic emission of thermal dielectrons from Au+Au collisions at ~GeV with EPOS3
Dileptons, as an electromagnetic probe, are crucial to study the properties
of a Quark-Gluon Plasma (QGP) created in heavy ion collisions. We calculated
the invariant mass spectra and the anisotropic emission of thermal dielectrons
from Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC) energy
~GeV based on EPOS3. This approach provides a realistic
(3+1)-dimensional event-by-event viscous hydrodynamic description of the
expanding hot and dense matter with a very particular initial condition, and a
large set of hadron data and direct photons (besides and !) can
be successfully reproduced. Thermal dilepton emission from both the QGP phase
and the hadronic gas are considered, with the emission rates based on Lattice
QCD and a vector meson model, respectively. We find that the computed invariant
mass spectra (thermal contribution + STAR cocktail) can reproduce the measured
ones from STAR at different centralities. Different compared to other model
predictions, the obtained elliptic flow of thermal dileptons is larger than the
STAR measurement referring to all dileptons. We observe a clear centrality
dependence of thermal dilepton not only for elliptic flow but also for
higher orders. At a given centrality, of thermal dileptons decreases
monotonically with for .Comment: 10pages, 12fig
Particles in classically forbidden area, neutron skin and halo, and pure neutron matter in Ca isotopes
The nucleon density distributions and the thickness of pure neutron matter in
Ca isotopes were systematically studied using the Skyrme-Hartree-Fock model
(SHF) from the -stability line to the neutron drip-line. The pure
neutron matter, related with the neutron skin or halo, was shown to depend not
only on the Fermi levels of the neutrons but also on the orbital angular
momentum of the valence neutrons. New definitions for the thickness of pure
neutron matter are proposed.Comment: 6 pages, 5 figure
iQIST : An open source continuous-time quantum Monte Carlo impurity solver toolkit
Quantum impurity solvers have a broad range of applications in theoretical studies of strongly correlated electron systems. Especially, they play a key role in dynamical mean-field theory calculations of correlated lattice models and realistic materials. Therefore, the development and implementation of efficient quantum impurity solvers is an important task. In this paper, we present an open source interacting quantum impurity solver toolkit (dubbed iQIST). This package contains several highly optimized quantum impurity solvers which are based on the hybridization expansion continuous-time quantum Monte Carlo algorithm, as well as some essential pre- and post-processing tools. We first introduce the basic principle of continuous-time quantum Monte Carlo algorithm and then discuss the implementation details and optimization strategies. The software framework, major features, and installation procedure for iQIST are also explained. Finally, several simple tutorials are presented in order to demonstrate the usage and power of iQIST
Single-Transverse Spin Asymmetry in Semi-Inclusive Deep Inelastic Scattering
We study the single-transverse spin asymmetry in semi-inclusive hadron
production in deep inelastic scattering. We derive the leading contribution to
the asymmetry at moderate transverse momentum of the produced
hadron in terms of twist-three quark-gluon correlation functions, and compare
with the approach based on the factorization at fixed transverse momentum
involving the asymmetric transverse-momentum and spin-dependent quark
distribution. We verify that the two approaches yield identical results in this
regime. By a comparison with our earlier calculations for the single-spin
asymmetry in the Drell-Yan process we recover the well-established
process-dependence of the time-reversal-odd transverse-momentum-dependent quark
distributions that generate single-spin phenomena.Comment: 17 pages, 3 figure
Depth-resolved holographic reconstructions by three-dimensional deconvolution
Methods of three-dimensional deconvolution with a point-spread function as
frequently employed in optical microscopy to reconstruct true three-dimensional
distribution of objects are extended to holographic reconstructions. Two such
schemes have been developed and are discussed: an instant deconvolution using
the Wiener filter as well as an iterative deconvolution routine. The instant
3d-deconvolution can be applied to restore the positions of volume-spread
objects such as small particles. The iterative deconvolution can be applied to
restore the distribution of complex and extended objects. Simulated and
experimental examples are presented and demonstrate artifact and noise free
three-dimensional reconstructions from a single two-dimensional holographic
record. Keywords: digital holography, volumetric deconvolution,
three-dimensional volumetric deconvolution, particle tracking, holographic
particle tracking, resolution, PSFComment: including MATLAB cod
A Foundational View on Integration Problems
The integration of reasoning and computation services across system and
language boundaries is a challenging problem of computer science. In this
paper, we use integration for the scenario where we have two systems that we
integrate by moving problems and solutions between them. While this scenario is
often approached from an engineering perspective, we take a foundational view.
Based on the generic declarative language MMT, we develop a theoretical
framework for system integration using theories and partial theory morphisms.
Because MMT permits representations of the meta-logical foundations themselves,
this includes integration across logics. We discuss safe and unsafe integration
schemes and devise a general form of safe integration
Star Formation Properties in Barred Galaxies(SFB). I. Ultraviolet-to-Infrared Imaging and Spectroscopic Studies of NGC 7479
Large-scale bars and minor mergers are important drivers for the secular
evolution of galaxies. Based on ground-based optical images and spectra as well
as ultraviolet data from the Galaxy Evolution Explorer and infrared data from
the Spitzer Space Telescope, we present a multi-wavelength study of star
formation properties in the barred galaxy NGC 7479, which also has obvious
features of a minor merger. Using various tracers of star formation, we find
that under the effects of both a stellar bar and a minor merger, star formation
activity mainly takes place along the galactic bar and arms, while the star
formation rate changes from the bar to the disk. With the help of spectral
synthesis, we find that strong star formation took place in the bar region
about 100 Myr ago, and the stellar bar might have been 10 Gyr old. By
comparing our results with the secular evolutionary scenario from Jogee et al.,
we suggest that NGC 7479 is possibly in a transitional stage of secular
evolution at present, and it may eventually become an earlier type galaxy or a
luminous infrared galaxy. We also note that the probable minor merger event
happened recently in NGC 7479, and we find two candidates for minor merger
remnants.Comment: 33 pages, 10 figures, 4 tables; accepted for publication in AJ, 142,
3
Dual Role of MoS in Polysulfide Conversion and Shuttle for Mg–S Batteries
Magnesium–Sulfur batteries are one of most appealing options among the post-lithium battery systems due to its potentially high energy density, safe and sustainable electrode materials. The major practical challenges are originated from the soluble magnesium polysulfide intermediates and their shuttling between the electrodes, which cause high overpotentials, low sulfur utilization, and poor Coulombic efficiency. Herein, a functional MoS modified separator is designed to effectively address these issues. Both the experimental results and density functional theory calculations show that the electrochemically active Mo6S8 layer has a superior adsorption capability of polysulfides and simultaneously acts as a mediator to accelerate the polysulfide conversion kinetics. Remarkably, the magnesium–sulfur cell assembled with the functional separator delivers a high specific energy density (942.9 mA h g in the 1st cycle) and can be cycled at 0.2 C for 200 cycles with a Coulombic efficiency of 96%. This work demonstrates a new design concept toward high-performance metal–sulfur batteries
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