1,791 research outputs found
Negative-Energy Spinors and the Fock Space of Lattice Fermions at Finite Chemical Potential
Recently it was suggested that the problem of species doubling with
Kogut-Susskind lattice fermions entails, at finite chemical potential, a
confusion of particles with antiparticles. What happens instead is that the
familiar correspondence of positive-energy spinors to particles, and of
negative-energy spinors to antiparticles, ceases to hold for the Kogut-Susskind
time derivative. To show this we highlight the role of the spinorial ``energy''
in the Osterwalder-Schrader reconstruction of the Fock space of non-interacting
lattice fermions at zero temperature and nonzero chemical potential. We
consider Kogut-Susskind fermions and, for comparison, fermions with an
asymmetric one-step time derivative.Comment: 14p
Issues and scenarios for nuclear waste management systems analysis
The Planning and Analysis Branch of the Department of Energy's Nuclear Waste Management Programs is developing a new systems integration program. The Pacific Northwest Laboratory was requested to perform a brief scoping analysis of what scenarios, questions, and issues should be addressed by the systems integration program. This document reports on that scoping analysis
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Glass: an available material for the immobilization of nuclear waste
This paper describes the properties of waste glass as it can be produced today, and shows how the properties of waste glass can fit into a multibarrier nuclear waste management system. The composition of the wastes that are to be immobilized and the design of processing equipment are also discussed
A Cross-Sectional Study of All Clinicians’ Conflict of Interest Disclosures to NHS Hospital Employers in England 2015-2016
Objective We set out to document how NHS trusts in the UK record and share disclosures of conflict of interest by their employees. Design Cross-sectional study of responses to a Freedom of Information Act request for Gifts and Hospitality Registers. Setting NHS Trusts (secondary/tertiary care organisations) in England. Participants 236 Trusts were contacted, of which 217 responded. Main outcome measures We assessed all disclosures for completeness and openness, scoring them for achieving each of five measures of transparency. Results 185 Trusts (78%) provided a register. 71 Trusts did not respond within the 28 day time limit required by the FoIA. Most COI registers were incomplete by design, and did not contain the information necessary to assess conflicts of interest. 126/185 (68%) did not record the names of recipients. 47/185 (25%) did not record the cash value of the gift or hospitality. Only 31/185 registers (16%) contained the names of recipients, the names of donors, and the cash amounts received. 18/185 (10%) contained none of: recipient name, donor name, and cash amount. Only 15 Trusts had their disclosure register publicly available online (6%). We generated a transparency index assessing whether each Trust met the following criteria: responded on time; provided a register; had a register with fields identifying donor, recipient, and cash amount; provided a register in a format that allowed further analysis; and had their register publicly available online. Mean attainment was 1.9/5; no NHS trust met all five criteria. Conclusion Overall, recording of employees’ conflicts of interest by NHS trusts is poor. None of the NHS Trusts in England met all transparency criteria. 19 did not respond to our FoIA requests, 51 did not provide a Gifts and Hospitality Register and only 31 of the registers provided contained enough information to assess employees’ conflicts of interest. Despite obligations on healthcare professionals to disclose conflicts of interest, and on organisations to record these, the current system for logging and tracking such disclosures is not functioning adequately. We propose a simple national template for reporting conflicts of interest, modelled on the US ‘Sunshine Act’
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Chemical durability of zinc borosilicate nuclear waste glass
Chemical durability is of primary concern when evaluating the safety of waste glass. For this reason, testing the leachability of waste glasses is a fundamental part of their development and characterization. The leachability is also very much a function of glass composition as previously discussed. This discussion is limited to a representative waste glass composition, a high-zinc borosilicate formulation which has been studied in detail by Battelle Pacific Northwest Laboratories. (GHT
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Waste Solidification Demonstration Program: Characterization of Nonradioactive Samples of Solidified High-Level Waste
The Savvidy ``ferromagnetic vacuum'' in three-dimensional lattice gauge theory
The vacuum effective potential of three-dimensional SU(2) lattice gauge
theory in an applied color-magnetic field is computed over a wide range of
field strengths. The background field is induced by an external current, as in
continuum field theory. Scaling and finite volume effects are analyzed
systematically. The first evidence from lattice simulations is obtained of the
existence of a nontrivial minimum in the effective potential. This supports a
``ferromagnetic'' picture of gluon condensation, proposed by Savvidy on the
basis of a one-loop calculation in (3+1)-dimensional QCD.Comment: 9pp (REVTEX manuscript). Postscript figures appende
The KMOS^3D Survey: design, first results, and the evolution of galaxy kinematics from 0.7<z<2.7
We present the KMOS^3D survey, a new integral field survey of over 600
galaxies at 0.7<z<2.7 using KMOS at the Very Large Telescope (VLT). The KMOS^3D
survey utilizes synergies with multi-wavelength ground and space-based surveys
to trace the evolution of spatially-resolved kinematics and star formation from
a homogeneous sample over 5 Gyrs of cosmic history. Targets, drawn from a
mass-selected parent sample from the 3D-HST survey, cover the star
formation-stellar mass () and rest-frame planes uniformly. We
describe the selection of targets, the observations, and the data reduction. In
the first year of data we detect Halpha emission in 191
Msun galaxies at z=0.7-1.1 and z=1.9-2.7. In
the current sample 83% of the resolved galaxies are rotation-dominated,
determined from a continuous velocity gradient and , implying
that the star-forming 'main sequence' (MS) is primarily composed of rotating
galaxies at both redshift regimes. When considering additional stricter
criteria, the Halpha kinematic maps indicate at least ~70% of the resolved
galaxies are disk-like systems. Our high-quality KMOS data confirm the elevated
velocity dispersions reported in previous IFS studies at z>0.7. For
rotation-dominated disks, the average intrinsic velocity dispersion decreases
by a factor of two from 50 km/s at z~2.3 to 25 km/s at z~0.9 while the
rotational velocities at the two redshifts are comparable. Combined with
existing results spanning z~0-3, disk velocity dispersions follow an
approximate (1+z) evolution that is consistent with the dependence of velocity
dispersion on gas fractions predicted by marginally-stable disk theory.Comment: 20 pages, 11 figures, 1 Appendix; Accepted to ApJ November 2
Recovering 3D structural properties of galaxies from SDSS-like photometry
Because of the 3D nature of galaxies, an algorithm for constructing spatial
density distribution models of galaxies on the basis of galaxy images has many
advantages over surface density distribution approximations. We present a
method for deriving spatial structure and overall parameters of galaxies from
images and estimate its accuracy and derived parameter degeneracies on a sample
of idealised model galaxies. The test galaxies consist of a disc-like component
and a spheroidal component with varying proportions and properties. Both
components are assumed to be axially symmetric and coplanar. We simulate these
test galaxies as if observed in the SDSS project through ugriz filters, thus
gaining a set of realistically imperfect images of galaxies with known
intrinsic properties. These artificial SDSS galaxies were thereafter remodelled
by approximating the surface brightness distribution with a 2D projection of a
bulge+disc spatial distribution model and the restored parameters were compared
to the initial ones. Down to the r-band limiting magnitude 18, errors of the
restored integral luminosities and colour indices remain within 0.05 mag and
errors of the luminosities of individual components within 0.2 mag. Accuracy of
the restored bulge-to-disc ratios (B/D) is within 40% in most cases, and
becomes worse for galaxies with low B/D, but the general balance between bulges
and discs is not shifted systematically. Assuming that the intrinsic disc axial
ratio is < 0.3, the inclination angles can be estimated with errors < 5deg for
most of the galaxies with B/D < 2 and with errors < 15deg up to B/D = 6. Errors
of the recovered sizes of the galactic components are below 10% in most cases.
In general, models of disc components are more accurate than models of
spheroidal components for geometrical reasons.Comment: 15 pages, 13 figures, accepted for publication in RA
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