767 research outputs found
Performance of early weaned calves fed lasalocid
Twenty-two newborn, bull calves were used to determine the effects of
lasalocid on growth and feed intake of early-weaned calves from week 1 to 12.
Calves were assigned to lasalocid or control groups on day 3. Lasalocid-fed group
received lasalocid in milk from day 4 to 7 and in milk and pre-starter from days 7
to 14 and in starter feed from weeks 2 to 12. Lasalocid-fed calves had a
significantly higher feed consumption and greater weight gain than calves that did
not receive lasalocid. The difference became apparent only after 6 wk of age.
Lasalocid appears to be a beneficial feed additive for newborn calves
Effect of route of administration of lasalocid on response of young dairy calves
Forty newborn bull calves were assigned to one of four feeding groups. The feeds
either contained lasalocid in milk (M), prestarter (PS), and starter (S); lasalocid in PS and S;
lasalocid in S only; or no lasalocid. Calves were fed M at 8% of birth weight (bw) daily and
offered PS to a maximum of 0.5 lb daily. When 0.5 lb of PS was consumed in one day the
calves were fed M at 4% of bw daily. They were weaned when they consumed dry feed at
the rate of 1.3% of bw. Daily feed intake and weekly weight gains of calves were evaluated.
Blood serum samples were used to evaluate blood metabolites at wk 4, 8, and 12. We
concluded that lasalocid in M, PS, and S supported greater feed efficiency and allowed earlier
weaning with less animal variation than when lasalocid was delivered in PS and S, only in S,
or not at all
Fermi edge singularities in X-ray spectra of strongly correlated fermions
We discuss the problem of the X-ray absorption in a system of interacting
fermions and, in particular, those features in the X-ray spectra that can be
used to discriminate between conventional Fermi-liquids and novel "strange
metals". Focusing on the case of purely forward scattering off the core-hole
potential, we account for the relevant interactions in the conduction band by
means of the bosonization technique. We find that the X-ray Fermi edge
singularities can still be present, although modified, even if the density of
states vanishes at the Fermi energy, and that, in general, the relationship
between the two appears to be quite subtle.Comment: Latex, 16 pages, Princeton preprin
'Hole-digging' in ensembles of tunneling Molecular Magnets
The nuclear spin-mediated quantum relaxation of ensembles of tunneling
magnetic molecules causes a 'hole' to appear in the distribution of internal
fields in the system. The form of this hole, and its time evolution, are
studied using Monte Carlo simulations. It is shown that the line-shape of the
tunneling hole in a weakly polarised sample must have a Lorentzian lineshape-
the short-time half-width in all experiments done so far should be
, the half-width of the nuclear spin multiplet. After a time
, the single molecule tunneling relaxation time, the hole width begins
to increase rapidly. In initially polarised samples the disintegration of
resonant tunneling surfaces is found to be very fast.Comment: 4 pages, 5 figure
Long-time behavior of an angiogenesis model with flux at the tumor boundary
This paper deals with a nonlinear system of partial differential equations
modeling a simplified tumor-induced angiogenesis taking into account only the
interplay between tumor angiogenic factors and endothelial cells. Considered
model assumes a nonlinear flux at the tumor boundary and a nonlinear
chemotactic response. It is proved that the choice of some key parameters
influences the long-time behaviour of the system. More precisely, we show the
convergence of solutions to different semi-trivial stationary states for
different range of parameters.Comment: 17 page
Study of solid 4He in two dimensions. The issue of zero-point defects and study of confined crystal
Defects are believed to play a fundamental role in the supersolid state of
4He. We report on studies by exact Quantum Monte Carlo (QMC) simulations at
zero temperature of the properties of solid 4He in presence of many vacancies,
up to 30 in two dimensions (2D). In all studied cases the crystalline order is
stable at least as long as the concentration of vacancies is below 2.5%. In the
2D system for a small number, n_v, of vacancies such defects can be identified
in the crystalline lattice and are strongly correlated with an attractive
interaction. On the contrary when n_v~10 vacancies in the relaxed system
disappear and in their place one finds dislocations and a revival of the
Bose-Einstein condensation. Thus, should zero-point motion defects be present
in solid 4He, such defects would be dislocations and not vacancies, at least in
2D. In order to avoid using periodic boundary conditions we have studied the
exact ground state of solid 4He confined in a circular region by an external
potential. We find that defects tend to be localized in an interfacial region
of width of about 15 A. Our computation allows to put as upper bound limit to
zero--point defects the concentration 0.003 in the 2D system close to melting
density.Comment: 17 pages, accepted for publication in J. Low Temp. Phys., Special
Issue on Supersolid
Have mirror micrometeorites been detected?
Slow-moving ( km/s) 'dark matter particles' have allegedly been
discovered in a recent experiment. We explore the possibility that these slow
moving dark matter particles are small mirror matter dust particles originating
from our solar system. Ways of further testing our hypothesis, including the
possibility of observing these dust particles in cryogenic detectors such as
NAUTILUS, are also discussed.Comment: Few changes, about 8 pages lon
Implications of the HERA Events for the R-Parity Breaking SUSY Signals at Tevatron
The favoured R-parity violating SUSY scenarios for the anomalous HERA events
correspond to top and charm squark production via the and
couplings. In both cases the corresponding electronic
branching fractions of the squarks are expected to be . Consequently the
canonical leptoquark signature is incapable of probing these scenarios at the
Tevatron collider over most of the MSSM parameter space. We suggest alternative
signatures for probing them at Tevatron, which seem to be viable over the
entire range of MSSM parameters.Comment: 20 pages Latex file with 4 ps files containing 4 figure
Quantum Theory in Accelerated Frames of Reference
The observational basis of quantum theory in accelerated systems is studied.
The extension of Lorentz invariance to accelerated systems via the hypothesis
of locality is discussed and the limitations of this hypothesis are pointed
out. The nonlocal theory of accelerated observers is briefly described.
Moreover, the main observational aspects of Dirac's equation in noninertial
frames of reference are presented. The Galilean invariance of nonrelativistic
quantum mechanics and the mass superselection rule are examined in the light of
the invariance of physical laws under inhomogeneous Lorentz transformations.Comment: 25 pages, no figures, contribution to Springer Lecture Notes in
Physics (Proc. SR 2005, Potsdam, Germany, February 13 - 18, 2005
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