2,400 research outputs found
Orientability of Fredholm families and topological degree
We construct a degree theory for oriented Fredholm mappings of index zero between open subsets of Banach spaces and between Banach manifolds. Our approach is based on the orientation of Fredholm mappings: it does not use Fredholm structures on the domain and target spaces. We provide a computable formula for the change in degree through an admissible homotopy that is necessary for applications to global bifurcation. The notion of orientation enables us to establish rather precise relationships between our degree and many other degree theories for particular classes of Fredholm maps, including the Elworthy-Tromba degree, which have appeared in the literature in a seemingly unrelated manner
On the covering dimension of the set of solutions of some nonlinear equations
We prove an abstract theorem whose sole hypothesis is that the degree of a certain map is nonzero and whose parametric equations are studied using cohomological mconclusions imply sharp, multidimensional continuation results. Applications are given to nonlinear partial differential equations
Complementing maps, continuation and global bifurcation
We state, and indicate some of the consequences of, a theorem whose sole assumption is the nonvanishing of the Leray- Schauder degree of a compact vector field, and whose conclusions yield multidimensional existence, continuation and bifurcation result
Bound states in weakly deformed waveguides: numerical vs analytical results
We have studied the emergence of bound states in weakly deformed and/or
heterogeneous waveguides, comparing the analytical predictions obtained using a
recently developed perturbative method, with precise numerical results, for
different configurations (a homogeneous asymmetric waveguide, a heterogenous
asymmetric waveguide and a homogeneous broken-strip). In all the examples
considered in this paper we have found excellent agreement between analytical
and numerical results, thus providing a numerical verification of the
analytical approach.Comment: 11 pages, 6 figure
Raman microprobe characterization of electrodeposited S-rich CuIn(S,Se)2 for photovoltaic applications: Microstructural analysis
This article reports a detailed Raman scattering and microstructural characterization of S-rich CuIn(S,Se)2 absorbers produced by electrodeposition of nanocrystalline CuInSe2 precursors and subsequent reactive annealing under sulfurizing conditions. Surface and in-depth resolved Raman microprobe measurements have been correlated with the analysis of the layers by optical and scanning electron microscopy, x-ray diffraction, and in-depth Auger electron spectroscopy. This has allowed corroboration of the high crystalline quality of the sulfurized layers. The sulfurizing conditions used also lead to the formation of a relatively thick MoS2 intermediate layer between the absorber and the Mo back contact. The analysis of the absorbers has also allowed identification of the presence of In-rich secondary phases, which are likely related to the coexistence in the electrodeposited precursors of ordered vacancy compound domains with the main chalcopyrite phase, in spite of the Cu-rich conditions used in the growth. This points out the higher complexity of the electrodeposition and sulfurization processes in relation to those based in vacuum deposition techniques
Computing Black Hole entropy in Loop Quantum Gravity from a Conformal Field Theory perspective
Motivated by the analogy proposed by Witten between Chern-Simons and
Conformal Field Theories, we explore an alternative way of computing the
entropy of a black hole starting from the isolated horizon framework in Loop
Quantum Gravity. The consistency of the result opens a window for the interplay
between Conformal Field Theory and the description of black holes in Loop
Quantum Gravity.Comment: 9 page
Intermittent hypoxic training and cycling performance in triathletes
Athletes include altitude training as a complement to their conventional training to improve performance. The aim of the study was to analyze the effects on anaerobic threshold (AT) produced by an IHT program in triathletes. 18 male trained triathletes were divided into intermittent hypoxic training group (GIHT: n=9; age: 26±6.73 years, height 173.33±5.94 cm, weight: 66.38±5.91 kg) and control group (GC: n=9; age: 29.27±6.84 years, height 174.89±4.59 cm, weight: 71.59±6.81 kg). The IHT program consisted of two 60-min sessions per week at intensities over the AT and atmospheric conditions between 14.5 and 15% FiO2. Before and after the program, cycling performance in a lactate thresholds test was determined. The treatment caused an improvement in the power output and perceived exertion in AT and enhanced cardiac performance in the aerobic threshold and AT.Actividad Física y Deport
Detailed black hole state counting in loop quantum gravity
We give a complete and detailed description of the computation of black hole
entropy in loop quantum gravity by employing the most recently introduced
number-theoretic and combinatorial methods. The use of these techniques allows
us to perform a detailed analysis of the precise structure of the entropy
spectrum for small black holes, showing some relevant features that were not
discernible in previous computations. The ability to manipulate and understand
the spectrum up to the level of detail that we describe in the paper is a
crucial step towards obtaining the behavior of entropy in the asymptotic (large
horizon area) regime
The Effect of Phosphorus Fertilization on Botanical Composition and Production in Temperate Pastures in Argentina
The objective of this paper is to evaluate floristic changes and above-ground primary production in native grasslands and old pastures dominated by tall fescue (Festuca arundinacea) that were fertilized with different levels of phosphorus. For this, aerial biomass was sequentially harvested from November 1998 to October 1999. Above-ground production of native grassland more than doubled (from 3000 to 7300 kg DM/ha) with the highest level of P through the increment of three naturalized species: the winter annual ryegrass (Lolium multiflorum) and two legumes: white clover (Trifolium repens) and lotus (Lotus corniculatus). In contrast, above-ground production of old fescue pastures remained unchanged while nutritive value improved as legumes and warm-season grasses increased where they were fertilized
Phase-space structure of two-dimensional excitable localized structures
In this work we characterize in detail the bifurcation leading to an
excitable regime mediated by localized structures in a dissipative nonlinear
Kerr cavity with a homogeneous pump. Here we show how the route can be
understood through a planar dynamical system in which a limit cycle becomes the
homoclinic orbit of a saddle point (saddle-loop bifurcation). The whole picture
is unveiled, and the mechanism by which this reduction occurs from the full
infinite-dimensional dynamical system is studied. Finally, it is shown that the
bifurcation leads to an excitability regime, under the application of suitable
perturbations. Excitability is an emergent property for this system, as it
emerges from the spatial dependence since the system does not exhibit any
excitable behavior locally.Comment: 10 pages, 9 figure
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