8,829 research outputs found
Comparison Between Geese, Peking Ducks and Mallards in Ability to Digest Common Rye-Grass
The aim of this digestibility experiment was to observe the differences between geese, peking ducks and mallards to digest common ryegrass (Lolium perenne L.). Adult birds were used for the trials. The grass was frozen after harvesting, stored until the experimental period and fed in fresh constitution. The birds were reared in special single cages and had free access to water and grass. Geese have the best adapted digestive tract of all waterfowl species to consume and digest high-fibre feedstuffs. Peking ducks are able to consume a lot of grass and it seems the digestibility values are similar to geese. The acceptance of mallards for grass is low but the feed value appears not strongly different from geese and peking ducks
Biologic Therapies for Severe Asthma
Biologic Therapies for Severe Asthma Patients with severe asthma are at increased risk for a decreased quality of life, fixed airway obstruction, hospitalization, and death. Biologics may be required to reduce the disease burden. This review discusses the mechanisms, efficacy, and safety of biologics for severe asthma
Nonlocal First-Order Hamilton-Jacobi Equations Modelling Dislocations Dynamics
We study nonlocal first-order equations arising in the theory of
dislocations. We prove the existence and uniqueness of the solutions of these
equations in the case of positive and negative velocities, under suitable
regularity assumptions on the initial data and the velocity. These results are
based on new -type estimates on the viscosity solutions of first-order
Hamilton-Jacobi Equations appearing in the so-called ``level-sets approach''.
Our work is inspired by and simplifies a recent work of Alvarez, Cardaliaguet
and Monneau
The bisymplectomorphism group of a bounded symmetric domain
An Hermitian bounded symmetric domain in a complex vector space, given in its
circled realization, is endowed with two natural symplectic forms: the flat
form and the hyperbolic form. In a similar way, the ambient vector space is
also endowed with two natural symplectic forms: the Fubini-Study form and the
flat form. It has been shown in arXiv:math.DG/0603141 that there exists a
diffeomorphism from the domain to the ambient vector space which puts in
correspondence the above pair of forms. This phenomenon is called symplectic
duality for Hermitian non compact symmetric spaces.
In this article, we first give a different and simpler proof of this fact.
Then, in order to measure the non uniqueness of this symplectic duality map, we
determine the group of bisymplectomorphisms of a bounded symmetric domain, that
is, the group of diffeomorphisms which preserve simultaneously the hyperbolic
and the flat symplectic form. This group is the direct product of the compact
Lie group of linear automorphisms with an infinite-dimensional Abelian group.
This result appears as a kind of Schwarz lemma.Comment: 19 pages. Version 2: minor correction
On the Large Time Behavior of Solutions of Hamilton-Jacobi Equations Associated with Nonlinear Boundary Conditions
In this article, we study the large time behavior of solutions of first-order
Hamilton-Jacobi Equations, set in a bounded domain with nonlinear Neumann
boundary conditions, including the case of dynamical boundary conditions. We
establish general convergence results for viscosity solutions of these
Cauchy-Neumann problems by using two fairly different methods : the first one
relies only on partial differential equations methods, which provides results
even when the Hamiltonians are not convex, and the second one is an optimal
control/dynamical system approach, named the "weak KAM approach" which requires
the convexity of Hamiltonians and gives formulas for asymptotic solutions based
on Aubry-Mather sets
HST/NICMOS Observations of Fast Infrared Flickering in the Microquasar GRS 1915+105
We report infrared observations of the microquasar GRS 1915+105 using the
NICMOS instrument of the Hubble Space Telescope during 9 visits in April-June
2003. During epochs of high X-ray/radio activity near the beginning and end of
this period, we find that the \um infrared flux is generally low ( mJy) and relatively steady. However, during the X-ray/radio ``plateau''
state between these epochs, we find that the infrared flux is significantly
higher ( mJy), and strongly variable. In particular, we find events
with amplitudes % occurring on timescales of s
(e-folding timescales of s). These flickering timescales are several
times faster than any previously-observed infrared variability in GRS 1915+105
and the IR variations exceed corresponding X-ray variations at the same () timescale. These results suggest an entirely new type of infrared
variability from this object. Based on the properties of this flickering, we
conclude that it arises in the plateau-state jet outflow itself, at a distance
AU from the accretion disk. We discuss the implications of this work and
the potential of further flickering observations for understanding jet
formation around black holes.Comment: 19 pages, incl. 4 figures; accepted for publication in Ap
V1647 Ori (IRAS 05436-0007) in Outburst: the First Three Months
We report on photometric (BVRIJHK) and low dispersion spectroscopic
observations of V1647 Ori, the star that drives McNeil's Nebula, between 10
February and 7 May 2004. The star is photometrically variable atop a general
decline in brightness of about 0.3-0.4 magnitudes during these 87 days. The
spectra are featureless, aside from H-alpha and the Ca II infrared triplet in
emission, and a Na I D absorption feature. The Ca II triplet line ratios are
typical of young stellar objects. The H-alpha equivalent width may be modulated
on a period of about 60 days. The post-outburst extinction appears to be less
than 7 mag. The data are suggestive of an FU Orionis-like event, but further
monitoring will be needed to definitively characterize the outburst.Comment: Accepted for publication in the Astronomical Journa
Large deviations in boundary-driven systems: Numerical evaluation and effective large-scale behavior
We study rare events in systems of diffusive fields driven out of equilibrium
by the boundaries. We present a numerical technique and use it to calculate the
probabilities of rare events in one and two dimensions. Using this technique,
we show that the probability density of a slowly varying configuration can be
captured with a small number of long wave-length modes. For a configuration
which varies rapidly in space this description can be complemented by a local
equilibrium assumption
Auxiliary master equation for nonequilibrium dual-fermion approach
We introduce auxiliary quantum master equation - dual fermion approach
(QME-DF) and argue that it presents a convenient way to describe steady-states
of correlated impurity systems. The combined scheme yields an expansion around
a reference much closer to the true nonequilibrium state than in the original
dual fermion formulation. In steady-state situations, the scheme is numerically
cheaper and allows to avoid long time propagation of previous considerations.
Anderson impurity is used as a test model. The QME-DF simulations are compared
with numerically exact tdDMRG results.Comment: 8 pages, 4 figure
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