9,672 research outputs found
Estimates of Scaling Violations for Pure SU(2) LGT
We investigate the approach of pure SU(2) lattice gauge theory with the
Wilson action to its continuum limit using the deconfining transition,
Luescher's gradient flow, and the cooling flow to set the scale. Of those, the
cooling flow turns out to be computationally most efficient. We explore
systematic errors due to use of three different energy observables and two
distinct reference values for the flow time, the latter obtained by matching
initial scaling behavior of some energy observables to that of the deconfining
transition. Another important source of systematic errors are distinct fitting
forms for the approach to the continuum limit. Besides relying in the
conventional way on ratios of masses, we elaborate on a form introduced by
Allton, which incorporates asymptotic scaling behavior. Ultimately we find
that, though still small, our systematic errors are considerably larger than
our statistical errors. ~Comment: 8 pages, 5 figures (lattice 2017 contribution
Analysis of free analyte fractions by rapid affinity chromatography
The invention is generally directed toward an analytical method to determine the concentration of the free analyte fraction in a sample. More particularly, the method encompasses applying a sample comprising a free and bound analyte fraction to an affinity column capable of selectively extracting the free fraction in the millisecond time domain. The signal generated by the free fraction is then quantified by standard analytical detection techniques. The concentration of the free fraction may then be determined by comparison of its signal with that of a calibration curve depicting the signal of known concentration of the same analyte
MHD simulations of the formation and propagation of protostellar jets to observational length scales
We present 2.5-D global, ideal MHD simulations of magnetically and
rotationally driven protostellar jets from Keplerian accretion discs, wherein
only the initial magnetic field strength at the inner radius of the disc,
, is varied. Using the AMR-MHD code AZEUS, we self-consistently
follow the jet evolution into the observational regime ()
with a spatial dynamic range of . The simulations reveal a
three-component outflow: 1) A hot, dense, super-fast and highly magnetised 'jet
core'; 2) a cold, rarefied, trans-fast and highly magnetised 'sheath'
surrounding the jet core and extending to a tangential discontinuity; and 3) a
warm, dense, trans-slow and weakly magnetised shocked ambient medium entrained
by the advancing bow shock. The simulations reveal power-law relationships
between and the jet advance speed, , the average jet
rotation speed, , as well as fluxes of mass,
momentum, and kinetic energy. Quantities that do not depend on
include the plasma- of the transported material which, in all cases,
seems to asymptote to order unity. Jets are launched by a combination of the
'magnetic tower' and 'bead-on-a-wire' mechanisms, with the former accounting
for most of the jet acceleration---even for strong fields---and continuing well
beyond the fast magnetosonic point. At no time does the leading bow shock leave
the domain and, as such, these simulations generate large-scale jets that
reproduce many of the observed properties of protostellar jets including their
characteristic speeds and transported fluxes.Comment: 26 pages, 16 figures. Accepted for publication in MNRA
Vehicle infrastructure cooperative localization using Factor Graphs
Highly assisted and Autonomous Driving is dependent on the accurate localization of both the vehicle and other targets within the environment. With increasing traffic on roads and wider proliferation of low cost sensors, a vehicle-infrastructure cooperative localization scenario can provide improved performance over traditional mono-platform localization. The paper highlights the various challenges in the process and proposes a solution based on Factor Graphs which utilizes the concept of topology of vehicles. A Factor Graph represents probabilistic graphical model as a bipartite graph. It is used to add the inter-vehicle distance as constraints while localizing the vehicle. The proposed solution is easily scalable for many vehicles without increasing the execution complexity. Finally simulation indicates that incorporating the topology information as a state estimate can improve performance over the traditional Kalman Filter approac
AZEuS: An Adaptive Zone Eulerian Scheme for Computational MHD
A new adaptive mesh refinement (AMR) version of the ZEUS-3D astrophysical
magnetohydrodynamical (MHD) fluid code, AZEuS, is described. The AMR module in
AZEuS has been completely adapted to the staggered mesh that characterises the
ZEUS family of codes, on which scalar quantities are zone-centred and vector
components are face-centred. In addition, for applications using static grids,
it is necessary to use higher-order interpolations for prolongation to minimise
the errors caused by waves crossing from a grid of one resolution to another.
Finally, solutions to test problems in 1-, 2-, and 3-dimensions in both
Cartesian and spherical coordinates are presented.Comment: 52 pages, 17 figures; Accepted for publication in ApJ
Stripes in thin ferromagnetic films with out-of-plane anisotropy
We examine the T=0 phase diagram of a thin ferromagnetic film with a strong
out-of-plane anisotropy in the vicinity of the reorientation phase transition
(with Co on Pt as an example). The phase diagram in the anisotropy-applied
field plane is universal in the limit where the film thickness is the shortest
length scale. It contains uniform fully magnetized and canted phases, as well
as periodically nonuniform states: a weakly modulated spin-density wave and
strongly modulated stripes. We determine the boundaries of metastability of
these phases and point out the existence of a critical point at which the
difference between the SDW and stripes vanishes. Out-of-plane magnetization
curves exhibit a variety of hysteresis loops caused by the coexistence of one
or more phases. Additionally, we study the effect of a system edge on the
orientation of stripes. We compare our results with recent experiments.Comment: added references and clarified derivations in response to referee
comment
Transitions in the morphological features, habitat use, and diet of young-of-the-year goosefish (Lophius americanus)
This study was designed to improve our understanding of transitions in the early life history and the distribution, habitat use, and diets for young-of-the-year (YOY) goosefish
(Lophius americanus) and, as a result, their role in northeastern U.S. continental shelf ecosystems. Pelagic juveniles (>12 to ca. 50 mm total length [TL]) were distributed over most portions of the continental shelf in the Middle Atlantic Bight, Georges Bank, and into the Gulf of Maine. Most individuals settled by 50−85 mm TL and reached approximately 60−120 mm TL by one year of age. Pelagic YOY fed on chaetognaths, hyperiid amphipods, calanoid copepods, and ostracods, and benthic YOY had a varied diet of fishes and benthic crustaceans. Goosefish are
widely scattered on the continental shelf in the Middle Atlantic Bight during their early life history and once settled, are habitat generalists, and thus play a role in many continental shelf habi
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