Beyond conventional factorization: Non-Hermitian Hamiltonians with radial oscillator spectrum

The eigenvalue problem of the spherically symmetric oscillator Hamiltonian is revisited in the context of canonical raising and lowering operators. The Hamiltonian is then factorized in terms of two not mutually adjoint factorizing operators which, in turn, give rise to a non-Hermitian radial Hamiltonian. The set of eigenvalues of this new Hamiltonian is exactly the same as the energy spectrum of the radial oscillator and the new square-integrable eigenfunctions are complex Darboux-deformations of the associated Laguerre polynomials.Comment: 13 pages, 7 figure

Scaling, genetic drift and clonal interference in the extinction pattern of asexual populations

We investigate the dynamics of loss of favorable mutations in an asexual haploid population. In the current work, we consider homogeneous as well as spatially structured population models. We focus our analysis on statistical measurements of the probability distribution of the maximum population size N(sb) achieved by those mutations that have not reached fixation. Our results show a crossover behavior which demonstrates the occurrence of two evolutionary regimes. In the first regime, which takes place for small N(sb) , the probability distribution is described by a power law with characteristic exponent theta(d) =1.8 +/- 0.01. This power law is not influenced by the rate of beneficial mutations. The second regime, which occurs for intermediate to large values of N(sb), has a characteristic exponent theta(c) which increases as the rate of beneficial mutations grows. These results establish where genetic drift and clonal interference become the main underlying mechanism in the extinction of advantageous mutations

Educação rodoviária: estudo de caso

A sinistralidade rodoviária transformou-se numa doença social, das principais causas de morte, internamentos, tratamentos prolongados e incapacidades permanentes. Com os programas de segurança rodoviária a sinistralidade rodoviária tem diminuído. Em que medida estes programas incluem a educação rodoviária? Na escolaridade obrigatória é (ou não) abordada a educação rodoviária? O que pensam os professores sobre esta temática nos currículos escolares? Usa-se o método comparativo na análise das orientações e programas internacionais sobre segurança rodoviária. Analisa-se em estudo de caso as representações de professores sobre a educação rodoviária nas escolas. A educação rodoviária constitui uma necessidade básica de aprendizagem para todos

El Alto y el Bajo Imperio

Síntesis arqueológica de las comarcas castellonenses entre los periodos romano y visigótico

FOODLIT-tool: Development and validation of the adaptable food literacy tool towards global sustainability within food systems

Facing multiple anthropogenic challenges and considering the current global pandemic, food sustainability is stated as threatened by major intergovernmental agencies. Given the heterogeneity of food systems, the need to enhance food-related behaviours by promoting the acquisition of knowledge and competencies, and the demand to involve stakeholder's diversity, this study aims to develop and validate an instrument that measures food literacy (FL), its determinants and its influential factors in an adult sample. Based on the Food Literacy Wheel (FLW) framework and integrated within the FOODLIT-PRO - Food Literacy Project, this study has three phases and a total of 2406 participants: (1) item development and content validity, (2) instrument development entailing item reduction strategies, factor extraction methodologies (exploratory and confirmatory analyses) and sensitivity testing, with two samples of a total of 1447 adults, and (3) instrument validation encompassing tests of dimensionality (confirmatory factor analysis), reliability (composite reliability) and validity (convergent and discriminant validity), and measure invariance testing, with 959 adults. Concerning statistical and psychometric properties, (1) a pool of 40 items (26 for FL; single items: five for determinants and nine for influential factors) was developed with inductive and deductive methodologies and reflected the FLW, (2) a 5-factor structure was explored, demonstrated acceptable model fit, and good sensitivity indices, and (3) a 5-dimensional reliable structure with 24 items was validated, configural invariance was achieved, and convergent and discriminant validity were significant in most dimensions. The FOODLIT-Tool contributes with an innovative measure of FL in adults that allows for a tailored assessment when approaching food-related issues within global food systems, providing a multidisciplinary tool that can be cross-widely applied to promote food-related behaviour change.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

The supersymmetric modified Poschl-Teller and delta-well potentials

New supersymmetric partners of the modified Poschl-Teller and the Dirac's delta well potentials are constructed in closed form. The resulting one-parametric potentials are shown to be interrelated by a limiting process. The range of values of the parameters for which these potentials are free of singularities is exactly determined. The construction of higher order supersymmetric partner potentials is also investigated.Comment: 20 pages, LaTeX file, 4 eps figure

Are the reported coralline red seaweeds species for the Macaronesian region taxonomically still valid?

43rd European Marine Biology Symposium. Ponta Delgada, Açores, 8-12 de Setembro de 2008

Taxonomy and distribution of rhodolith beds from the Azores, Portugal.

2nd International Rhodolith Workshop. Ciencias Marinas, Universidad Autónoma de Baja California Sur, La Paz, B.C.S., México, 23-29 de Outubro de 2006

Quantum mechanical spectral engineering by scaling intertwining

Using the concept of spectral engineering we explore the possibilities of building potentials with prescribed spectra offered by a modified intertwining technique involving operators which are the product of a standard first-order intertwiner and a unitary scaling. In the same context we study the iterations of such transformations finding that the scaling intertwining provides a different and richer mechanism in designing quantum spectra with respect to that given by the standard intertwiningComment: 8 twocolumn pages, 5 figure