909 research outputs found
The Birman-Schwinger Operator for a Parabolic Quantum Well in a Zero-Thickness Layer in the Presence of a Two-Dimensional Attractive Gaussian Impurity
ProducciĂłn CientĂficaVer abstrac
Spectral properties of the two-dimensional Schrödinger Hamiltonian with various solvable confinements in the presence of a central point perturbation
We study three solvable two-dimensional systems perturbed by a point interaction centered at the
origin. The unperturbed systems are the isotropic harmonic oscillator, a square pyramidal
potential and a combination thereof. We study the spectrum of the perturbed systems. We show
that, while most eigenvalues are not affected by the point perturbation, a few of them are strongly
perturbed. We show that for some values of one parameter, these perturbed eigenvalues may take
lower values than the immediately lower eigenvalue, so that level crossings occur. These level
crossings are studied in some detail
Clumsiness and Motor Competence in Physical Education and Sport Pedagogy
One of the main objectives of physical education and sport (PES) pedagogy in schools is to develop motor competence in children. While many schoolchildren practice sports, there is a group of children that does not receive the educational opportunities to be competent. These children show low motor competence and poor motor coordination. International agencies have called this condition as developmental coordination disorders (DCD) and its definition in short is “poor motor performance in daily activities that is not consistent with the child’s age and intelligence, and is not due to medical condition.” Physical education and sport teachers are the first interventionist with these children. They have the first opportunity of providing primary care to these children. In this chapter, motor coordination problems in school, its prevalence, how these children learn, how physical education and sport teachers can detect them, and why physical education and sport pedagogy must be concerned with this problem, will be analyzed
Geodiversity as a Tool for the Nature Conservation
Geodiversity and biodiversity are the two fundamental components of Nature that must be analyzed simultaneously for good management of the natural environment. Geodiversity, including geomorphodiversity, has values that make it possible to define the geosystem services on the basis of which it is possible to establish protocols for the sustainable development of the territory analyzed. Both the values of geodiversity and the geosystem services they provide are key elements for the definition of Natural Protected Areas (NPAs). Furthermore, it is also necessary to consider the assessment of the geodiversity and geomorphodiversity of the territory under consideration, so that a zoning can be established in terms of the geodiversity index (geodiversity/geomorphodiversity gradient) that favors the establishment of specific geoconservation protocols according to the value of these indices. In addition, NPAs should be considered as elements belonging to a network in which the different natural systems of the territory in which the network is defined are represented. In the case of geodiversity or geomorphodiversity, the network must be supported by the definition of geological contexts, representative of the major geological units that are observable in the territory
Coherent states for a generalization of the harmonic oscillator
Coherent states for a family of isospectral oscillator Hamiltonians are derived from a suitable choice of annihilation and creation operators. The Fock-Bargmann representation is also obtained
Quadratic Hamiltonians in phase-space quantum mechanics
The dynamical evolution is described within the phase-space
formalism by means of the Moyal propagator, which is the symbol of the
evolution operator. Quadratic Hamiltonians on the phase space are
distinguished in that their Moyal bracket with any function equals
their Poisson bracket. It is shown that, for general time-independent
quadratic Hamiltonians, the Moyal propagators transform covariantly
under linear canonical transformations; they are then derived and
classified in a fully explicit manner using the theory of Hamiltonian
normal forms. We present several tables of propagators. It is proved
that these propagators belong to the Moyal algebra of distributions,
and that the spectrum of the Hamiltonian may be obtained directly as
the support of the Fourier transform of the Moyal propagator with
respect to time. From that, the quantum-mechanical problem for these
Hamiltonians is in principle completely solved. The appropriate
path-integral formalism for phase-space quantum mechanics, leading
back to the same results, is outlined in appendix.UCR::VicerrectorĂa de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Matemátic
The Frailes alluvial-travertine system (Alcalá la Real Neogene-Quaternary Basin, Jaén province, Betic Cordillera)
On study an alluvial-travertine complex system located near to Frailes village (Betic Cordillera, Jaén province).
It is made up of two steps with their flat top located at 930 and 1026 m a.s.l. The lower one prograding to
N130ÂşE is mainly formed by allochthonous travertine facies. The upper step consists of alluvial and travertine
facies. There are two detrital facies associations, characteristic of alluvial fan, and three carbonate facies
associations consisting of allochthonous and bioconstructed travertine sediments, oncolite and stromatolite
facies. The carbonate facies associations were deposited in pool-dam-cascade sub-environments. The
progradation of the upper step is to N210Âş
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