14,977 research outputs found
Effect of neck cut position on time to collapse in halal slaughtered cattle without stunning
This study examined the effect of neck cut position on the time to physical collapse in upright restrained halal slaughtered cattle (n = 644). Time to collapse was used as an indirect indicator of the early stages of onset of unconsciousness. Cattle were slaughtered with either a conventional low (LNC) (n = 561) or a high neck cut (HNC) (n = 83). Mean time to final collapse was higher in the LNC compared to HNC group (18.9 ± 1.1 s and 13.5 ± 1.3 s respectively (P 20 s to final collapse had larger false aneurysms. In summary, the HNC reduced the mean time to final collapse and the frequency of animals that took longer than 20 s to collapse
Charged Condensate and Helium Dwarf Stars
White dwarf stars composed of carbon, oxygen or heavier elements are expected
to crystallize as they cool down below certain temperatures. Yet, simple
arguments suggest that the helium white dwarf cores may not solidify, mostly
because of zero-point oscillations of the helium ions that would dissolve the
crystalline structure. We argue that the interior of the helium dwarfs may
instead form a macroscopic quantum state in which the charged helium-4 nuclei
are in a Bose-Einstein condensate, while the relativistic electrons form a
neutralizing degenerate Fermi liquid. We discuss the electric charge screening,
and the spectrum of this substance, showing that the bosonic long-wavelength
fluctuations exhibit a mass gap. Hence, there is a suppression at low
temperatures of the boson contribution to the specific heat -- the latter being
dominated by the specific heat of the electrons near the Fermi surface. This
state of matter may have observational signatures.Comment: 10 pages; v2: to appear in JCAP, brief comments and section titles
added, typos correcte
The Green's function for the radial Schramm-Loewner evolution
We prove the existence of the Green's function for radial SLE(k) for k<8.
Unlike the chordal case where an explicit formula for the Green's function is
known for all values of k<8, we give an explicit formula only for k=4. For
other values of k, we give a formula in terms of an expectation with respect to
SLE conditioned to go through a point.Comment: v1: 16 pages, 0 figure
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Glucocorticoid-regulated localization of cell surface glycoproteins in rat hepatoma cells is mediated within the Golgi complex.
Glucocorticoid hormones regulate the post-translational maturation and sorting of cell surface and extracellular mouse mammary tumor virus (MMTV) glycoproteins in M1.54 cells, a stably infected rat hepatoma cell line. Exposure to monensin significantly reduced the proteolytic maturation and externalization of viral glycoproteins resulting in a stable cellular accumulation of a single 70,000-Mr glycosylated polyprotein (designated gp70). Cell surface- and intracellular-specific immunoprecipitations of monensin-treated cells revealed that gp70 can be localized to the cell surface only in the presence of 1 microM dexamethasone, while in uninduced cells gp70 is irreversibly sequestered in an intracellular compartment. Analysis of oligosaccharide processing kinetics demonstrated that gp70 acquired resistance to endoglycosidase H with a half-time of 65 min in the presence or absence of hormone. In contrast, gp70 was inefficiently galactosylated after a 60-min lag in uninduced cells while rapidly acquiring this carbohydrate modification in the presence of dexamethasone. Furthermore, in the absence or presence of monensin, MMTV glycoproteins failed to be galactosylated in hormone-induced CR4 cells, a complement-selected sorting variant defective in the glucocorticoid-regulated compartmentalization of viral glycoproteins to the cell surface. Since dexamethasone had no apparent global effects on organelle morphology or production of total cell surface-galactosylated species, we conclude that glucocorticoids induce the localization of cell surface MMTV glycoproteins by regulating a highly selective step within the Golgi apparatus after the acquisition of endoglycosidase H-resistant oligosaccharide side chains but before or at the site of galactose attachment
A universe in a global monopole
We investigate brane physics in a universe with an extra dimensional global
monopole and negative bulk cosmological constant. The graviton zero mode is
naturally divergent; we thus invoke a physical cut-off to induce four
dimensional gravity on a brane at the monopole core. Independently, the massive
Kaluza-Klein modes have naturally compactified extra dimensions, inducing a
discrete spectrum. This spectrum remains consistent with four dimensional
gravity on the brane, even for small mass gap. Extra dimensional matter fields
also induce four dimensional matter fields on the brane, with the same
Kaluza-Klein spectrum of excited states. We choose parameters to solve the
hierarchy problem; that is, to induce the observed hierarchy between particle
and Planck scales in the effective four dimensional universe.Comment: 22 pages, 2 eps figures, revte
Inflating magnetically charged braneworlds
Numerical solutions of Einstein, scalar, and gauge field equations are found
for static and inflating defects in a higher-dimensional spacetime. The defects
have -dimensional core and magnetic monopole configuration in
extra dimensions. For symmetry-breaking scale below the critical value
, the defects are characterized by a flat worldsheet geometry and
asymptotically flat extra dimensions. The critical scale is comparable
to the higher-dimensional Planck scale and has some dependence on the gauge and
scalar couplings. For , the extra dimensions degenerate into a
`cigar', and for all static solutions are singular. The
singularity can be removed if the requirement of staticity is relaxed and
defect cores are allowed to inflate. The inflating solutions have de Sitter
worldsheets and cigar geometry in the extra dimensions. Exact analytic
solutions describing the asymptotic behavior of these inflating monopoles are
found and the parameter space of these solutions is analyzed.Comment: 35 pages, revtex, 18 eps figure
Local 4/5-Law and Energy Dissipation Anomaly in Turbulence
A strong local form of the ``4/3-law'' in turbulent flow has been proved
recently by Duchon and Robert for a triple moment of velocity increments
averaged over both a bounded spacetime region and separation vector directions,
and for energy dissipation averaged over the same spacetime region. Under
precisely stated hypotheses, the two are proved to be proportional, by a
constant 4/3, and to appear as a nonnegative defect measure in the local energy
balance of singular (distributional) solutions of the incompressible Euler
equations. Here we prove that the energy defect measure can be represented also
by a triple moment of purely longitudinal velocity increments and by a mixed
moment with one longitudinal and two tranverse velocity increments. Thus, we
prove that the traditional 4/5- and 4/15-laws of Kolmogorov hold in the same
local sense as demonstrated for the 4/3-law by Duchon-Robert.Comment: 14 page
Zerobrane Matrix Mechanics, Monopoles and Membrane Approach in QCD
We conjecture that a T-dual form of pure QCD describes dynamics of point-like
monopoles. T-duality transforms the QCD Lagrangian into a matrix quantum
mechanics of zerobranes which we identify with monopoles. At generic points of
the monopole moduli space the SU(N) gauge group is broken down to
reproducing the key feature of 't Hooft's Abelian projection. There are certain
points in the moduli space where monopole positions coincide, gauge symmetry is
enhanced and gluons emerge as massless excitations. We show that there is a
linearly rising potential between zerobranes. This indicates the presence of a
stretched flux tube between monopoles. The lowest energy state is achieved when
monopoles are sitting on top of each other and gauge symmetry is enhanced. In
this case they behave as free massive particles and can condense. In fact, we
find a constant eigenfunction of the corresponding Hamiltonian which describes
condensation of monopoles. Using the monopole quantum mechanics, we argue that
large QCD in this T-dual picture is a theory of a closed bosonic membrane
propagating in {\em five} dimensional space-time. QCD point-like monopoles can
be regarded in this approach as constituents of the membrane.Comment: 16 pages, new section and references adde
Nonsingular global string compactifications
We consider an exotic `compactification' of spacetime in which there are two
infinite extra dimensions, using a global string instead of a domain wall. By
having a negative cosmological constant we prove the existence of a nonsingular
static solution using a dynamical systems argument. A nonsingular solution also
exists in the absence of a cosmological constant with a time-dependent metric.
We compare and contrast this solution with the Randall-Sundrum universe and the
Cohen-Kaplan spacetime, and consider the options of using such a model as a
realistic resolution of the hierarchy problem.Comment: 8 pages revtex, 1 figure : References added and equation correcte
Supergravity and The Large N Limit of Theories With Sixteen Supercharges
We consider field theories with sixteen supersymmetries, which includes U(N)
Yang-Mills theories in various dimensions, and argue that their large N limit
is related to certain supergravity solutions. We study this by considering a
system of D-branes in string theory and then taking a limit where the brane
worldvolume theory decouples from gravity. At the same time we study the
corresponding D-brane supergravity solution and argue that we can trust it in
certain regions where the curvature (and the effective string coupling, where
appropriate) are small. The supergravity solutions typically have several
weakly coupled regions and interpolate between different limits of
string-M-theory.Comment: 24 pages, latex. v2: reference added, v3: typos correcte
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