6,150 research outputs found
BG Group and “Conditions” to Arbitral Jurisdiction
Although the Supreme Court has over the last decade generated a robust body of arbitration caselaw, its first decision in the area of investment arbitration under a Bilateral Investment Treaty was only handed down in 2014. BG Group v. Argentina was widely anticipated and has attracted much notice, and general approval, on the part of the arbitration community. In this paper we assess the Court’s decision from two different perspectives—the first attempts to situate it in the discourse of the American law of commercial arbitration; the second considers it in light of the expectations of the international community surrounding the proper construction of Conventions between states.
Our initial goal had been to write jointly, with the hope that we could bridge our differences to find, if not common, at least neighboring, ground. On some points we did so, but ultimately our divergent appreciations of the proper way to interpret the condition precedent in the investment treaty in BG Group overcame the idealism with which we commenced the project. Nonetheless we have decided to present the two papers together to emphasize the dichotomous approaches to treaty interpretation that two moderately sensible people, who inhabit overlapping but non-congruent interpretive communities, can have.The Kay Bailey Hutchison Center for Energy, Law, and Busines
Chiral Hadronic Mean Field Model including Quark Degrees of Freedom
In an approach inspired by Polyakov loop extended NJL models, we present a
nonlinear hadronic SU(3) sigma-omega mean field model augmented by quark
degrees of freedom. By introducing the effective Polyakov loop related scalar
field \Phi and an associated effective potential, the model includes all known
hadronic degrees of freedom at low temperatures and densities as well as a
quark phase at high temperatures and densities. Hadrons in the model exhibit a
finite volume in order to suppress baryons at high T and \mu. This ensures that
the right asymptotic degrees of freedom are attained for the description of
strongly interacting matter and allows to study the QCD phase diagram in a wide
range of temperatures and chemical potentials. Therefore, with this model it is
possible to study the phase transition of chiral restoration and deconfinement.
In this paper, the impact of quarks on the resulting phase diagram is shown.
The results from the chiral model are compared to recent data from lattice QCD.Comment: 25 pages, 10 figure
Efficient implementation of the adaptive scale pixel decomposition algorithm
Context. Most popular algorithms in use to remove the effects of a
telescope's point spread function (PSF) in radio astronomy are variants of the
CLEAN algorithm. Most of these algorithms model the sky brightness using the
delta-function basis, which results in undesired artefacts when used on image
extended emission. The adaptive scale pixel decomposition (Asp-Clean) algorithm
models the sky brightness on a scale-sensitive basis and thus gives a
significantly better imaging performance when imaging fields that contain both
resolved and unresolved emission.
Aims. However, the runtime cost of Asp-Clean is higher than that of
scale-insensitive algorithms. In this paper, we identify the most expensive
step in the original Asp-Clean algorithm and present an efficient
implementation of it, which significantly reduces the computational cost while
keeping the imaging performance comparable to the original algorithm. The PSF
sidelobe levels of modern wide-band telescopes are significantly reduced,
allowing us to make approximations to reduce the computing cost, which in turn
allows for the deconvolution of larger images on reasonable timescales.
Methods. As in the original algorithm, scales in the image are estimated
through function fitting. Here we introduce an analytical method to model
extended emission, and a modified method for estimating the initial values used
for the fitting procedure, which ultimately leads to a lower computational
cost.
Results.The new implementation was tested with simulated EVLA data and the
imaging performance compared well with the original Asp-Clean algorithm. Tests
show that the current algorithm can recover features at different scales with
lower computational cost.Comment: 6 pages; 4 figure
Gamma-Ray Bursts Observed with the Spectrometer SPI Onboard INTEGRAL
The spectrometer SPI is one of the main detectors of ESA's INTEGRAL mission.
The instrument offers two interesting and valuable capabilities for the
detection of the prompt emission of Gamma-ray bursts. Within a field of view of
16 degrees, SPI is able to localize Gamma-ray bursts with an accuracy of 10
arcmin. The large anticoincidence shield, ACS, consisting of 512 kg of BGO
crystals, detects Gamma-ray bursts quasi omnidirectionally above ~70 keV. Burst
alerts from SPI/ACS are distributed to the interested community via the
INTEGRAL Burst Alert System. The ACS data have been implemented into the 3rd
Interplanetary Network and have proven valuable for the localization of bursts
using the triangulation method. During the first 8 months of the mission
approximately one Gamma-ray burst per month was localized within the field of
fiew of SPI and 145 Gamma-ray burst candidates were detected by the ACS from
which 40 % have been confirmed by other instruments.Comment: 4 pages, 2 figures, to appear in the Proceedings of the Conference
"30 Years of GRB Discovery", Santa Fe, New Mexico, USA, September 8-12, 200
High-precision measurement of the deuteron’s atomic mass
- In the framework of this thesis, a measurement campaign on the atomic mass of the deuteron, the nucleus of deuterium, was conducted at the Penning-trap experiment Liontrap (Light-Ion TRAP). For this purpose, major parts of the original experimental facility were rebuilt and improved. The measurement principle at Liontrap is based on a comparison of the cyclotron frequency of the ion to of interest and the cyclotron frequency of a carbon ion. From this, the mass in atomic mass units is deduced. Liontrap is optimized on the special requirements of light ions, as inconsistencies in the combination of different measurements hamper the use of their mass values for applications for example in neutrino physics. In the measurement campaign, it was possible to measure the atomic mass of deuteron with a relative precision of 8.5 · 10−12. This is the most precise measurement in atomic mass units to date. The value is a factor 2.4 more precise than the previously most precise measurement and shows a discrepancy of 5 standard deviations. Additionally, a measurement of the molecular ion HD+ was conducted. The mass of this molecular ion can be derived from the masses of the deuteron and the proton, previously also measured at Liontrap. The atomic mass of the electron and the molecular binding energy are sufficiently known to not add an additional uncertainty. Both values for the atomic mass of HD+ agree, giving a strong confidence check of the measurement methods used at Liontrap
Advances in Calibration and Imaging Techniques in Radio Interferometry
This paper summarizes some of the major calibration and image reconstruction
techniques used in radio interferometry and describes them in a common
mathematical framework. The use of this framework has a number of benefits,
ranging from clarification of the fundamentals, use of standard numerical
optimization techniques, and generalization or specialization to new
algorithms
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