996 research outputs found
Rigid upper bounds for the angular momentum and centre of mass of non-singular asymptotically anti-de Sitter space-times
We prove upper bounds on angular momentum and centre of mass in terms of the
Hamiltonian mass and cosmological constant for non-singular asymptotically
anti-de Sitter initial data sets satisfying the dominant energy condition. We
work in all space-dimensions larger than or equal to three, and allow a large
class of asymptotic backgrounds, with spherical and non-spherical conformal
infinities; in the latter case, a spin-structure compatibility condition is
imposed. We give a large class of non-trivial examples saturating the
inequality. We analyse exhaustively the borderline case in space-time dimension
four: for spherical cross-sections of Scri, equality together with completeness
occurs only in anti-de Sitter space-time. On the other hand, in the toroidal
case, regular non-trivial initial data sets saturating the bound exist.Comment: improvements in the presentation; some statements correcte
Implant strategies for finishing calves
Two hundred-sixteen Angus and Angus-cross
steer calves (690 lb) were used in a 129-
day finishing study to evaluate different implant
strategies, including an experimental new
implant for feedlot cattle that contains 28 mg of
estradiol benzoate and 200 mg of trenbolone
acetate (EBTBA). Treatments were 1)
nonimplanted control, 2) implanted and
reimplanted with Synovex-Sfi, 3) single initial
implant with EBTBA, 4) single initial implant
with Revalor-Sfi, 5) implanted with Synovex-S
and reimplanted with EBTBA, and 6) implanted
and reimplanted with EBTBA. Initial implants
and reimplants were administered on day 0 and
63, respectively. All implant treatments
increased feed intake, slaughter and carcass
weights, and rate and efficiency of gain.
Compared with other implant treatments, the
use of EBTBA as a reimplant treatment (trts 5
and 6) resulted in improved (P<.08) rate and
efficiency of gain and heavier carcass weights
(P<.07). However, only 58.3% of cattle in trts
5 and 6 graded Choice vs. 86.1% for controls
and 80.6% for steers implanted twice with
Synovex-S (P<.07). Carcasses were more
masculine (P<.07) for steers in trts 5 and 6 than
for nonimplanted controls, steers implanted with
Revalor-S, and steers implanted twice with
Synovex-S. Performance of steers implanted
once with EBTBA did not differ from that of
steers implanted once with Revalor-S or twice
with Synovex-S, but carcasses were more
masculine (P<.07) for EBTBA vs. Revalor-S
steers. Implant treatment
did not affect meat tenderness, as
measured by Warner-Bratzler shear force
determinations. Single EBTBA or Revalor-S
implants resulted in performance and carcass
traits similar to those resulting from implanting
twice with Synovex-S
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A specialist toxicity database (TRACE) is more effective than its larger, commercially available counterparts
A comparison of the retrieval precision and recall of a specialist bibliographic toxicity database (TRACE) with that of a wide range of commercial on-line databases indicated that the larger size and resources of the commercial databases did not, for a series of test queries, assure superior retrieval of relevant papers. The specialist database, in which document selection and indexing is undertaken by the same (in this case) expert toxicologists who subsequently use the database in their day-to-day work, achieved markedly better retrieval, using simpler search strategies, than the commercial databases. Small specialist databases may offer a valuable alternative to existing commercial databases
An explicit height bound for the classical modular polynomial
For a prime m, let Phi_m be the classical modular polynomial, and let
h(Phi_m) denote its logarithmic height. By specializing a theorem of Cohen, we
prove that h(Phi_m) <= 6 m log m + 16 m + 14 sqrt m log m. As a corollary, we
find that h(Phi_m) <= 6 m log m + 18 m also holds. A table of h(Phi_m) values
is provided for m <= 3607.Comment: Minor correction to the constants in Theorem 1 and Corollary 9. To
appear in the Ramanujan Journal. 17 pages
Excavation at Aguas Buenas, Robinson Crusoe Island, Chile, of a gunpowder magazine and the supposed campsite of Alexander Selkirk, together with an account of early navigational dividers
Excavations were undertaken of a ruined building at Aguas Buenas, identified as an 18th-century Spanish gunpowder magazine. Evidence was also found for the campsite of an early European occupant of the island. A case is made that this was Alexander Selkirk, a castaway here from 1704 to 1709. Selkirk was the model for Defoe’s Robinson Crusoe. A detailed discussion is given of a fragment of copper alloy identifi ed as being from a pair of navigational dividers
Ground state properties of the 2D disordered Hubbard model
We study the ground state of the two-dimensional (2D) disordered Hubbard
model by means of the projector quantum Monte Carlo (PQMC) method. This
approach allows us to investigate the ground state properties of this model for
lattice sizes up to , at quarter filling, for a broad range of
interaction and disorder strengths. Our results show that the ground state of
this system of spin-1/2 fermions remains localised in the presence of the
short-ranged Hubbard interaction.Comment: 7 pages, 9 figure
Static black holes with a negative cosmological constant: Deformed horizon and anti-de Sitter boundaries
Using perturbative techniques, we investigate the existence and properties of
a new static solution for the Einstein equation with a negative cosmological
constant, which we call the deformed black hole. We derive a solution for a
static and axisymmetric perturbation of the Schwarzschild-anti-de Sitter black
hole that is regular in the range from the horizon to spacelike infinity. The
key result is that this perturbation simultaneously deforms the two boundary
surfaces--i.e., both the horizon and spacelike two-surface at infinity. Then we
discuss the Abbott-Deser mass and the Ashtekar-Magnon one for the deformed
black hole, and according to the Ashtekar-Magnon definition, we construct the
thermodynamic first law of the deformed black hole. The first law has a
correction term which can be interpreted as the work term that is necessary for
the deformation of the boundary surfaces. Because the work term is negative,
the horizon area of the deformed black hole becomes larger than that of the
Schwarzschild-anti-de Sitter black hole, if compared under the same mass,
indicating that the quasistatic deformation of the Schwarzschild-anti-de Sitter
black hole may be compatible with the thermodynamic second law (i.e., the area
theorem).Comment: 31 pages, 5 figures, one reference added, to be published in PR
Solving variational inequalities defined on a domain with infinitely many linear constraints
We study a variational inequality problem whose domain is defined by infinitely many linear inequalities. A discretization method and an analytic center based inexact cutting plane method are proposed. Under proper assumptions, the convergence results for both methods are given. We also provide numerical examples to illustrate the proposed method
Schwinger-Keldysh Approach to Disordered and Interacting Electron Systems: Derivation of Finkelstein's Renormalization Group Equations
We develop a dynamical approach based on the Schwinger-Keldysh formalism to
derive a field-theoretic description of disordered and interacting electron
systems. We calculate within this formalism the perturbative RG equations for
interacting electrons expanded around a diffusive Fermi liquid fixed point, as
obtained originally by Finkelstein using replicas. The major simplifying
feature of this approach, as compared to Finkelstein's is that instead of replicas, we only need to consider N=2 species. We compare the dynamical
Schwinger-Keldysh approach and the replica methods, and we present a simple and
pedagogical RG procedure to obtain Finkelstein's RG equations.Comment: 22 pages, 14 figure
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