480 research outputs found
Spatial patterns of African ungulate aggregation reveal complex but limited risk effects from reintroduced carnivores
pi-NN Coupling Constants from NN Elastic Data between 210 and 800 Mev
High partial waves for and elastic scattering are examined
critically from 210 to 800 MeV. Non-OPE contributions are compared with
predictions from theory. There are some discrepancies, but sufficient agreement
that values of the coupling constants for exchange
and for charged exchange can be derived. Results are and , where the first error is statistical and the
second is an estimate of the likely systematic error, arising mostly from
uncertainties in the normalisation of total cross sections and
.Comment: 21 pages of LaTeX, UI-NTH-940
Clinical and laboratory variability in a cohort of patients diagnosed with type 1 VWD in the United States
Von Willebrand disease (VWD) is the most common inherited bleeding disorder, and type 1
VWD is the most common VWD variant. Despite its frequency, diagnosis of type 1 VWD
remains the subject of much debate. In order to study the spectrum of type 1 VWD in the United
States, the Zimmerman Program enrolled 482 subjects with a previous diagnosis of type 1 VWD
without stringent laboratory diagnostic criteria. VWF laboratory testing and full length VWF
gene sequencing were performed for all index cases and healthy control subjects in a central
laboratory. Bleeding phenotype was characterized using the ISTH Bleeding Assessment Tool.
At study entry, 64% of subjects had VWF:Ag or VWF:RCo below the lower limit of normal,
while 36% had normal VWF levels. VWF sequence variations were most frequent in subjects
with VWF:Ag < 30 IU/dL (82%) while subjects with type 1 VWD and VWF:Ag â„ 30 IU/dL had
an intermediate frequency of variants (44%). Subjects whose VWF testing was normal at study
entry had a similar rate of sequence variations as the healthy controls at 14% of subjects. All
subjects with severe type 1 VWD and VWF:Ag †5 IU/dL had an abnormal bleeding score, but
otherwise bleeding score did not correlate with VWF:Ag level. Subjects with a historical
diagnosis of type 1 VWD had similar rates of abnormal bleeding scores compared to subjects
with low VWF levels at study entry. Type 1 VWD in the United States is highly variable, and
bleeding symptoms are frequent in this population
Quantum control and the Strocchi map
Identifying the real and imaginary parts of wave functions with coordinates
and momenta, quantum evolution may be mapped onto a classical Hamiltonian
system. In addition to the symplectic form, quantum mechanics also has a
positive-definite real inner product which provides a geometrical
interpretation of the measurement process. Together they endow the quantum
Hilbert space with the structure of a K\"{a}ller manifold. Quantum control is
discussed in this setting. Quantum time-evolution corresponds to smooth
Hamiltonian dynamics and measurements to jumps in the phase space. This adds
additional power to quantum control, non unitarily controllable systems
becoming controllable by ``measurement plus evolution''. A picture of quantum
evolution as Hamiltonian dynamics in a classical-like phase-space is the
appropriate setting to carry over techniques from classical to quantum control.
This is illustrated by a discussion of optimal control and sliding mode
techniques.Comment: 16 pages Late
Orbitally Driven Spin Pairing in the 3D Non-Magnetic Mott Insulator BaVS3: Evidence from Single Crystal Studies
Static electrical and magnetic properties of single crystal BaVS_3 were
measured over the structural (T_S=240K), metal-insulator (T_MI=69K), and
suspected orbital ordering (T_X=30K) transitions. The resistivity is almost
isotropic both in the metallic and insulating states. An anomaly in the
magnetic anisotropy at T_X signals a phase transition to an ordered low-T
state. The results are interpreted in terms of orbital ordering and spin
pairing within the lowest crystal field quasi-doublet. The disordered insulator
at T_X<T<T_MI is described as a classical liquid of non-magnetic pairs.Comment: 4 pages, 5 figures, revtex, epsf, and multicol style. Problem with
figures fixed. To appear in Phys. Rev. B Rap. Com
Introduction of Empirical Topology in Construction of Relationship Networks of Informative Objects
Understanding the structure of relationships between objects in a given
database is one of the most important problems in the field of data mining. The
structure can be defined for a set of single objects (clustering) or a set of
groups of objects (network mapping). We propose a method for discovering
relationships between individuals (single or groups) that is based on what we
call the empirical topology, a system-theoretic measure of functional
proximity. To illustrate the suitability and efficiency of the method, we apply
it to an astronomical data base
Mixing and coherent structures in two-dimensional viscous flows
We introduce a dynamical description based on a probability density
of the vorticity in two-dimensional viscous flows
such that the average vorticity evolves according to the Navier-Stokes
equations. A time-dependent mixing index is defined and the class of
probability densities that maximizes this index is studied. The time dependence
of the Lagrange multipliers can be chosen in such a way that the masses
m(\sigma,t):=\intdxdy \phi(\sigma,x,y,t) associated with each vorticity value
are conserved. When the masses are conserved then 1) the
mixing index satisfies an H-theorem and 2) the mixing index is the
time-dependent analogue of the entropy employed in the statistical mechanical
theory of inviscid 2D flows [Miller, Weichman & Cross, Phys. Rev. A \textbf{45}
(1992); Robert & Sommeria, Phys. Rev. Lett. \textbf{69}, 2776 (1992)]. Within
this framework we also show how to reconstruct the probability density of the
quasi-stationary coherent structures from the experimentally determined
vorticity-stream function relations and we provide a connection between this
probability density and an appropriate initial distribution
Proposed measurement of tagged deep inelastic scattering in Hall A of Jefferson lab
A tagged deep inelastic scattering (TDIS) experiment is planned for Hall A of Jefferson Lab, which will probe the mesonic content of the nucleon directly. Low momentum recoiling (and spectator) protons will be measured in coincidence with electrons scattered in a deep inelastic regime from hydrogen (and deuterium) targets, covering kinematics of 8 < W2 < 18 GeV2, 1 < Q2 < 3 (GeV/c)2 and 0.05 < x < 0.2. The tagging technique will help identify scattering from partons in the meson cloud and provide access to the pion structure function via the Sullivan process. The experiment will yield the first TDIS results in the valence regime, for both proton and neutron targets. We present here an overview of the experiment
Generalized thermodynamics and Fokker-Planck equations. Applications to stellar dynamics, two-dimensional turbulence and Jupiter's great red spot
We introduce a new set of generalized Fokker-Planck equations that conserve
energy and mass and increase a generalized entropy until a maximum entropy
state is reached. The concept of generalized entropies is rigorously justified
for continuous Hamiltonian systems undergoing violent relaxation. Tsallis
entropies are just a special case of this generalized thermodynamics.
Application of these results to stellar dynamics, vortex dynamics and Jupiter's
great red spot are proposed. Our prime result is a novel relaxation equation
that should offer an easily implementable parametrization of geophysical
turbulence. This relaxation equation depends on a single key parameter related
to the skewness of the fine-grained vorticity distribution. Usual
parametrizations (including a single turbulent viscosity) correspond to the
infinite temperature limit of our model. They forget a fundamental systematic
drift that acts against diffusion as in Brownian theory. Our generalized
Fokker-Planck equations may have applications in other fields of physics such
as chemotaxis for bacterial populations. We propose the idea of a
classification of generalized entropies in classes of equivalence and provide
an aesthetic connexion between topics (vortices, stars, bacteries,...) which
were previously disconnected.Comment: Submitted to Phys. Rev.
Safety and efficacy of eculizumab in the prevention of antibody-mediated rejection in living-donor kidney transplant recipients requiring desensitization therapy: A randomized trial
We report results of a phase 2, randomized, multicenter, openâlabel, twoâarm study
evaluating the safety and efficacy of eculizumab in preventing acute antibodyâ
mediated rejection (AMR) in sensitized recipients of livingâdonor kidney transplants
requiring pretransplant desensitization (NCT01399593). In total, 102 patients underâ
went desensitization. Posttransplant, 51 patients received standard of care (SOC)
and 51 received eculizumab. The primary end point was week 9 posttransplant treatâ
ment failure rate, a composite of: biopsyâproven acute AMR (Banff 2007 grade II or
III; assessed by blinded central pathology); graft loss; death; or loss to followâup. Eculizumab was well tolerated with no new safety concerns. No significant difference
in treatment failure rate was observed between eculizumab (9.8%) and SOC (13.7%;
P = .760). To determine whether data assessment assumptions affected study outâ
come, biopsies were reanalyzed by central pathologists using clinical information. The
resulting treatment failure rates were 11.8% and 21.6% for the eculizumab and SOC
groups, respectively (nominal P = .288). When reassessment included grade I AMR,
the treatment failure rates were 11.8% (eculizumab) and 29.4% (SOC; nominal
P = .048). This finding suggests a potential benefit for eculizumab compared with
SOC in preventing acute AMR in recipients sensitized to their livingâdonor kidney
transplants (EudraCT 2010â019630â28)
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