698 research outputs found
High performance computation of landscape genomic models integrating local indices of spatial association
Since its introduction, landscape genomics has developed quickly with the
increasing availability of both molecular and topo-climatic data. The current
challenges of the field mainly involve processing large numbers of models and
disentangling selection from demography. Several methods address the latter,
either by estimating a neutral model from population structure or by inferring
simultaneously environmental and demographic effects. Here we present
Samada, an integrated approach to study signatures of local adaptation,
providing rapid processing of whole genome data and enabling assessment of
spatial association using molecular markers. Specifically, candidate loci to
adaptation are identified by automatically assessing genome-environment
associations. In complement, measuring the Local Indicators of Spatial
Association (LISA) for these candidate loci allows to detect whether similar
genotypes tend to gather in space, which constitutes a useful indication of the
possible kinship relationship between individuals. In this paper, we also
analyze SNP data from Ugandan cattle to detect signatures of local adaptation
with Samada, BayEnv, LFMM and an outlier method (FDIST approach in
Arlequin) and compare their results. Samada is an open source software
for Windows, Linux and MacOS X available at \url{http://lasig.epfl.ch/sambada}Comment: 1 figure in text, 1 figure in supplementary material The structure of
the article was modified and some explanations were updated. The methods and
results presented are the same as in the previous versio
Breve história da lei de biossegurança do Brasil.
bitstream/item/192268/1/ARTIGO-2-Maria-Pedrozo.pd
Longtime behavior of nonlocal Cahn-Hilliard equations
Here we consider the nonlocal Cahn-Hilliard equation with constant mobility
in a bounded domain. We prove that the associated dynamical system has an
exponential attractor, provided that the potential is regular. In order to do
that a crucial step is showing the eventual boundedness of the order parameter
uniformly with respect to the initial datum. This is obtained through an
Alikakos-Moser type argument. We establish a similar result for the viscous
nonlocal Cahn-Hilliard equation with singular (e.g., logarithmic) potential. In
this case the validity of the so-called separation property is crucial. We also
discuss the convergence of a solution to a single stationary state. The
separation property in the nonviscous case is known to hold when the mobility
degenerates at the pure phases in a proper way and the potential is of
logarithmic type. Thus, the existence of an exponential attractor can be proven
in this case as well
Simultaneous Continuation of Infinitely Many Sinks Near a Quadratic Homoclinic Tangency
We prove that the diffeomorphisms on surfaces, exhibiting infinitely
many sinksnear the generic unfolding of a quadratic homoclinic tangency of a
dissipative saddle, can be perturbed along an infinite dimensional manifold of
diffeomorphisms such that infinitely many sinks persist simultaneously.
On the other hand, if they are perturbed along one-parameter families that
unfold generically the quadratic tangencies, then at most a finite number of
those sinks have continuation
Incorporating Inductances in Tissue-Scale Models of Cardiac Electrophysiology
In standard models of cardiac electrophysiology, including the bidomain and
monodomain models, local perturbations can propagate at infinite speed. We
address this unrealistic property by developing a hyperbolic bidomain model
that is based on a generalization of Ohm's law with a Cattaneo-type model for
the fluxes. Further, we obtain a hyperbolic monodomain model in the case that
the intracellular and extracellular conductivity tensors have the same
anisotropy ratio. In one spatial dimension, the hyperbolic monodomain model is
equivalent to a cable model that includes axial inductances, and the relaxation
times of the Cattaneo fluxes are strictly related to these inductances. A
purely linear analysis shows that the inductances are negligible, but models of
cardiac electrophysiology are highly nonlinear, and linear predictions may not
capture the fully nonlinear dynamics. In fact, contrary to the linear analysis,
we show that for simple nonlinear ionic models, an increase in conduction
velocity is obtained for small and moderate values of the relaxation time. A
similar behavior is also demonstrated with biophysically detailed ionic models.
Using the Fenton-Karma model along with a low-order finite element spatial
discretization, we numerically analyze differences between the standard
monodomain model and the hyperbolic monodomain model. In a simple benchmark
test, we show that the propagation of the action potential is strongly
influenced by the alignment of the fibers with respect to the mesh in both the
parabolic and hyperbolic models when using relatively coarse spatial
discretizations. Accurate predictions of the conduction velocity require
computational mesh spacings on the order of a single cardiac cell. We also
compare the two formulations in the case of spiral break up and atrial
fibrillation in an anatomically detailed model of the left atrium, and [...].Comment: 20 pages, 12 figure
Towards a liquid Argon TPC without evacuation: filling of a 6 m^3 vessel with argon gas from air to ppm impurities concentration through flushing
In this paper we present a successful experimental test of filling a volume
of 6 m with argon gas, starting from normal ambient air and reducing the
impurities content down to few parts per million (ppm) oxygen equivalent. This
level of contamination was directly monitored measuring the slow component of
the scintillation light of the Ar gas, which is sensitive to {\it all} sources
of impurities affecting directly the argon scintillation.Comment: 9 pages, 6 figures, to appear in Proc. 1st International Workshop
towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba,
March 201
Hardware-in-the-loop performance analysis of a railway traction system under sensor faults
Fault mode and effects analysis (FMEA) has been used during decades for analysing the effects of faults in different applications. Initially, FMEA based on risk priority numbers provided information about the effects in the system, but during the last years different approaches have been developed to obtain a more robust risk evaluation. The proposed enhanced FMEA can provide the quantitative effects of sensor faults in a railway traction drive, in variables such as torque, current and voltages. In addition to the previous work, quantitative effects on overall performance indicators, such as energy efficiency and comfort, are obtained too. Hardware-in-the-loop (HIL)-based fault injection approach has been used to generate fault scenarios. The test platform is composed of a real-time simulator and a commercial traction control unit for a railway application
Health Industries in the Twentieth Century. Introduction
This article is the introduction to the special issue' Health Industries in the Twentieth Century'. It offers a broad literature review of scholarly works about the history of health and medicine, and stresses the opportunities for business historians to tackle the field of healthcare
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