2,888 research outputs found
A note on the effect of supplementation with microbial phytase and organic acids on feed intake and growth performance of growing pigs
peer-reviewedThis experiment was designed to investigate the effects of supplementation with phytase, either alone or in combination with organic acids, on feed intake and growth of pigs from 8 to 89 kg live weight. Some 240 pigs were used in four experimental treatments comprising: (1) control, (2) control plus phytase, (3) control plus phytase plus liquid organic acids (formic, propionic), and (4) control plus phytase plus powdered organic acids (formic, fumaric, propionic). Feed intake and growth rate in the weaner stage were increased (P < 0.05) by phytase supplementation, with some additional benefits from organic acid inclusion. Interval to slaughter was reduced (P < 0.05) by phytase supplementation
Flight elements: Fault detection and fault management
Fault management for an intelligent computational system must be developed using a top down integrated engineering approach. An approach proposed includes integrating the overall environment involving sensors and their associated data; design knowledge capture; operations; fault detection, identification, and reconfiguration; testability; causal models including digraph matrix analysis; and overall performance impacts on the hardware and software architecture. Implementation of the concept to achieve a real time intelligent fault detection and management system will be accomplished via the implementation of several objectives, which are: Development of fault tolerant/FDIR requirement and specification from a systems level which will carry through from conceptual design through implementation and mission operations; Implementation of monitoring, diagnosis, and reconfiguration at all system levels providing fault isolation and system integration; Optimize system operations to manage degraded system performance through system integration; and Lower development and operations costs through the implementation of an intelligent real time fault detection and fault management system and an information management system
The Beta Problem: A Study of Abell 262
We present an investigation of the dynamical state of the cluster A262.
Existing optical line of sight velocities for select cluster galaxies have been
augmented by new data obtained with the Automated Multi-Object Spectrograph at
Lick Observatory. We find evidence for a virialized early-type population
distinct from a late-type population infalling from the Pisces-Perseus
supercluster ridge. We also report on a tertiary population of low luminosity
galaxies whose velocity dispersion distinguishes them from both the early and
late-type galaxies. We supplement our investigation with an analysis of
archival X-ray data. A temperature is determined using ASCA GIS data and a gas
profile is derived from ROSAT HRI data. The increased statistics of our sample
results in a picture of A262 with significant differences from earlier work. A
previously proposed solution to the "beta-problem" in A262 in which the gas
temperature is significantly higher than the galaxy temperature is shown to
result from using too low a velocity dispersion for the early-type galaxies.
Our data present a consistent picture of A262 in which there is no
"beta-problem", and the gas and galaxy temperature are roughly comparable.
There is no longer any requirement for extensive galaxy-gas feedback to
drastically overheat the gas with respect to the galaxies. We also demonstrate
that entropy-floor models can explain the recent discovery that the beta values
determined by cluster gas and the cluster core radii are correlated.Comment: 31 pages, 14 figures, AAS LaTeX v5.0, Encapsulated Postscript
figures, to be published in The Astrophysical Journa
Indirect age- and sex-standardisation of COVID-19-related mortality rates for the prison population of England and Wales
This paper estimates a standardised mortality ratio (SMR) for death due to COVID-19 among people in prisons in England and Wales between 1 March 2020 and 26 February 2021. Over this period, prisons in England and Wales reported 121 deaths related to COVID-19. The SMR is 3.33 (95% C.I. 2.77–3.98), meaning there were 3.33 times more deaths among people in prisons than expected given the age and sex of the population
Resolving the virial discrepancy in clusters of galaxies with modified Newtonian dynamics
A sample of 197 X-ray emitting clusters of galaxies is considered in the
context of Milgrom's modified Newtonian dynamics (MOND). It is shown that the
gas mass, extrapolated via an assumed model to a fixed radius of 3 Mpc,
is correlated with the gas temperature as predicted by MOND (). The observed temperatures are generally consistent with the inferred
mass of hot gas; no substantial quantity of additional unseen matter is
required in the context of MOND. However, modified dynamics cannot resolve the
strong lensing discrepancy in those clusters where this phenomenon occurs. The
prediction is that additional baryonic matter may be detected in the central
regions of rich clusters.Comment: Submitted to A&A, 4 pages, 3 figures, A&A macro
Effects of Galaxy Formation on Thermodynamics of the Intracluster Medium
We present detailed comparisons of the intracluster medium (ICM) in
cosmological Eulerian cluster simulations with deep Chandra observations of
nearby relaxed clusters. To assess the impact of galaxy formation, we compare
two sets of simulations, one performed in the non-radiative regime and another
with radiative cooling and several physical processes critical to various
aspects of galaxy formation: star formation, metal enrichment and stellar
feedback. We show that the observed ICM properties outside cluster cores are
well-reproduced in the simulations that include cooling and star formation,
while the non-radiative simulations predict an overall shape of the ICM
profiles inconsistent with observations. In particular, we find that the ICM
entropy in our runs with cooling is enhanced to the observed levels at radii as
large as half of the virial radius. We also find that outside cluster cores
entropy scaling with the mean ICM temperature in both simulations and Chandra
observations is consistent with being self-similar within current error bars.
We find that the pressure profiles of simulated clusters are also close to
self-similar and exhibit little cluster-to-cluster scatter. The X-ray
observable-total mass relations for our simulated sample agree with the Chandra
measurements to \~10%-20% in normalization. We show that this systematic
difference could be caused by the subsonic gas motions, unaccounted for in
X-ray hydrostatic mass estimates. The much improved agreement of simulations
and observations in the ICM profiles and scaling relations is encouraging and
the existence of tight relations of X-ray observables, such as Yx, and total
cluster mass and the simple redshift evolution of these relations hold promise
for the use of clusters as cosmological probes.Comment: 14 pages, 6 figures. Matches version accepted to Ap
Wigner-Poisson statistics of topological transitions in a Josephson junction
The phase-dependent bound states (Andreev levels) of a Josephson junction can
cross at the Fermi level, if the superconducting ground state switches between
even and odd fermion parity. The level crossing is topologically protected, in
the absence of time-reversal and spin-rotation symmetry, irrespective of
whether the superconductor itself is topologically trivial or not. We develop a
statistical theory of these topological transitions in an N-mode quantum-dot
Josephson junction, by associating the Andreev level crossings with the real
eigenvalues of a random non-Hermitian matrix. The number of topological
transitions in a 2pi phase interval scales as sqrt(N) and their spacing
distribution is a hybrid of the Wigner and Poisson distributions of
random-matrix theory.Comment: 12 pages, 15 figures; v2 to appear in PRL, with appendix in the
supplementary materia
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