10,597 research outputs found
The genomes and history of domestic animals
This paper reviews how mammalian genomes are utilized in modern genetics for the detection of genes and polymorphisms (mutations) within domesticated animal (mostly livestock) genomes that are related to traits of economic importance to humans. Examples are given of how genetic analysis allows to determine key genes associated with the quality and quantity of milk in cattle and key genes for meat production. Various questions are reviewed, such as how contemporary methods of genome sequencing allow to maximise the effective detection of coding and regulatory DNA polymorphisms within the genomes of major domesticated mammals (cattle, sheep and pigs) and the history of their formation from the standpoint of genetics
Binary fluid amplifier solves stability and load problems
Digital fluid amplifier has load intensity, high stability, and operates at low reynolds numbers. It contains specially designed nozzles to provide uniform exit-velocity profiles and to ensure jets of low turbulence
Fate of the inert three-flavor, spin-zero color-superconducting phases
I investigate some of the inert phases in three-flavor, spin-zero
color-superconducting quark matter: the CFL phase (the analogue of the B phase
in superfluid ), the A and A* phases, and the 2SC and sSC phases. I
compute the pressure of these phases with and without the neutrality condition.
It is shown that the 2SC phase is identical to the A* phase up to a color
rotation. The CFL phase is the energetically favored phase except for a small
region of intermediate densities where the 2SC/A* phase is favored.Comment: 9 pages, 1 figure; the version accepted to publish in PR
A constrained random-force model for weakly bending semiflexible polymers
The random-force (Larkin) model of a directed elastic string subject to
quenched random forces in the transverse directions has been a paradigm in the
statistical physics of disordered systems. In this brief note, we investigate a
modified version of the above model where the total transverse force along the
polymer contour and the related total torque, in each realization of disorder,
vanish. We discuss the merits of adding these constraints and show that they
leave the qualitative behavior in the strong stretching regime unchanged, but
they reduce the effects of the random force by significant numerical
prefactors. We also show that a transverse random force effectively makes the
filament softer to compression by inducing undulations. We calculate the
related linear compression coefficient in both the usual and the constrained
random force model.Comment: 4 pages, 1 figure, accepted for publication in PR
Induced superfluidity of imbalanced Fermi gases near unitarity
The induced intraspecies interactions among the majority species, mediated by
the minority species, is computed for a population-imbalanced two-component
Fermi gas. Although the Feshbach-resonance mediated interspecies interaction is
dominant for equal populations, leading to singlet s-wave pairing, we find that
in the strongly imbalanced regime the induced intraspecies interaction leads to
p-wave pairing and superfluidity of the majority species. Thus, we predict that
the observed spin-polaron Fermi liquid state in this regime is unstable to
p-wave superfluidity, in accordance with the results of Kohn and Luttinger,
below a temperature that, near unitarity, we find to be within current
experimental capabilities. Possible experimental signatures of the p-wave state
using radio-frequency spectroscopy as well as density-density correlations
after free expansion are presented.Comment: 15 pages, 13 figures, submitted to Phys. Rev.
Vortex Viscosity in Magnetic Superconductors Due to Radiation of Spin Waves
In type-II superconductors that contain a lattice of magnetic moments,
vortices polarize the magnetic system inducing additional contributions to the
vortex mass, vortex viscosity, and vortex-vortex interaction. Extra magnetic
viscosity is caused by radiation of spin waves by a moving vortex. Like in the
case of Cherenkov radiation, this effect has a characteristic threshold
behavior and the resulting vortex viscosity may be comparable to the well-known
Bardeen-Stephen contribution. The threshold behavior leads to an anomaly in the
current-voltage characteristics, and a drop in dissipation for a current
interval that is determined by the magnetic excitation spectrum.Comment: 4 pages, 1 figur
Conventional and charge six superfluids from melting hexagonal Fulde-Ferrell-Larkin-Ovchinnikov phases in two dimensions
We consider defect mediated melting of Fulde-Ferrell-Larkin-Ovchinnikov
(FFLO) and pair density wave (PDW) phases in two dimensions. Examining
mean-field ground states in which the spatial oscillations of the FFLO/PDW
superfluid order parameter exhibit hexagonal lattice symmetry, we find that
thermal melting leads to a variety of novel phases. We find that a spatially
homogeneous charge six superfluid can arise from melting a hexagonal
vortex-anitvortex lattice FFLO/PDW phase. The charge six superfluid has an
order parameter corresponding to a bound state of six fermions. We further find
that a hexagonal vortex-free FFLO/PDW phase can melt to yield a conventional
(charge two) homogeneous superfluid. A key role is played by topological
defects that combine fractional vortices of the superfluid order and fractional
dislocations of the lattice order.Comment: 8 pages, 3 figure
Superfluid phases of triplet pairing and neutrino emission from neutron stars
Neutrino energy losses through neutral weak currents in the triplet-spin
superfluid neutron liquid are studied for the case of condensate involving
several magnetic quantum numbers. Low-energy excitations of the multicomponent
condensate in the timelike domain of the energy and momentum are analyzed.
Along with the well-known excitations in the form of broken Cooper pairs, the
theoretical analysis predicts the existence of collective waves of spin density
at very low energy. Because of a rather small excitation energy of spin waves,
their decay leads to a substantial neutrino emission at the lowest
temperatures, when all other mechanisms of neutrino energy loss are killed by a
superfluidity. Neutrino energy losses caused by the pair recombination and
spin-wave decays are examined in all of the multicomponent phases that might
represent the ground state of the condensate, according to modern theories, and
for the case when a phase transition occurs in the condensate at some
temperature. Our estimate predicts a sharp increase in the neutrino energy
losses followed by a decrease, along with a decrease in the temperature, that
takes place more rapidly than it would without the phase transition. We
demonstrate the important role of the neutrino radiation caused by the decay of
spin waves in the cooling of neutron stars.Comment: 24 pages, 5 figure
Pairing of a trapped resonantly-interacting fermion mixture with unequal spin populations
We consider the phase separation of a trapped atomic mixture of fermions with
unequal spin populations near a Feshbach resonance. In particular, we determine
the density profile of the two spin states and compare with the recent
experiments of Partridge et al. (cond-mat/0511752). Overall we find quite good
agreement. We identify the remaining discrepancies and pose them as open
problems.Comment: 4 figures, 4+ pages, revtex
Criticality in inhomogeneous magnetic systems: Application to quantum ferromagnets
We consider a -theory with a position-dependent distance from the
critical point. One realization of this model is a classical ferromagnet
subject to non-uniform mechanical stress. We find a sharp phase transition
where the envelope of the local magnetization vanishes uniformly. The
first-order transition in a quantum ferromagnet also remains sharp. The
universal mechanism leading to a tricritical point in an itinerant quantum
ferromagnet is suppressed, and in principle one can recover a quantum critical
point with mean-field exponents. Observable consequences of these results are
discussed.Comment: 4pp, 4 eps figs, contains additional information compared to PRL
version. PRl, in pres
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