Imagina que eres... Indagación sobre el uso de la lengua común en contexto matemático en la escuela media

Este artículo presenta los resultados de una investigación, realizada en la escuela media, sobre el uso de la lengua natural en contexto matemático, y sobre la producción de modelos externos en torno a las concepciones profundas de algunos conceptos elementales que poseen los alumnos. Con una técnica que invita a los alumnos a asumir un papel diferente del que usualmente juegan en la clase de matemáticas, se intentaba empujarlos a escribir acerca de asuntos matemáticos elementales en un lenguaje coloquial, sin los aparatos formales que con frecuencia exhiben. No obstante haber acogido bien el juego del cambio de papel que les propusimos y haber respondido a las situaciones problemáticas usando lengua natural, la mayoría de los alumnos presentó la tendencia a completar su respuesta inicial con una respuesta formal, a menudo vacía, que tenía poco que ver con la tarea. En casos en que los alumnos no usaron aparatos formales para responder se identificaron modelos que resultan interesantes en el plano de verificación de los aprendizajes

Variational collocation for systems of coupled anharmonic oscillators

We have applied a collocation approach to obtain the numerical solution to the stationary Schr\"odinger equation for systems of coupled oscillators. The dependence of the discretized Hamiltonian on scale and angle parameters is exploited to obtain optimal convergence to the exact results. A careful comparison with results taken from the literature is performed, showing the advantages of the present approach.Comment: 14 pages, 10 table

Inversion of perturbation series

We investigate the inversion of perturbation series and its resummation, and prove that it is related to a recently developed parametric perturbation theory. Results for some illustrative examples show that in some cases series reversion may improve the accuracy of the results

Variational collocation on finite intervals

In this paper we study a new family of sinc--like functions, defined on an interval of finite width. These functions, which we call ``little sinc'', are orthogonal and share many of the properties of the sinc functions. We show that the little sinc functions supplemented with a variational approach enable one to obtain accurate results for a variety of problems. We apply them to the interpolation of functions on finite domain and to the solution of the Schr\"odinger equation, and compare the performance of present approach with others.Comment: 12 pages, 8 figures, 1 tabl

Fungal solid state fermentation on agro-industrial wastes for acid wastewater decolourization in a continuous flow packed-bed bioreactor

This study was aimed at developing a process of solid state fermentation (SSF) with the fungi Pleurotus ostreatus and Trametes versicolor on apple processing residues for wastewater decolorization. Both fungi were able to colonize apple residues without any addition of nutrients, material support or water. P. ostreatus produced the highest levels of laccases (up to 9 U g-1 of dry matter) and xylanases (up to 80 U g-1 of dry matter). A repeated batch decolorization experiment was set up with apple residues colonized by P. ostreatus, achieving 50% decolorization and 100% detoxification after 24 h, and, adding fresh wastewater every 24 h, a constant decolorization of 50% was measured for at least 1 month. A continuous decolorization experiment was set up by a packed-bed reactor based on colonized apple residues achieving a performance of 100 mg dye L-1 day-1 at a retention time of 50

The confined hydrogen atom with a moving nucleus

We study the hydrogen atom confined to a spherical box with impenetrable walls but, unlike earlier pedagogical articles on the subject, we assume that the nucleus also moves. We obtain the ground-state energy approximately by means of first--order perturbation theory and by a more accurate variational approach. We show that it is greater than the one for the case in which the nucleus is clamped at the center of the box. Present approach resembles the well-known treatment of the helium atom with clamped nucleus

Pay Dispersion and Executive Behaviour:Evidence from Innovation

Compensation packages are widely used to motivate top executives. Pay dispersion among a firm’s executives, however, can be associated with the antithetic effects of social comparison and individual motivation, with unclear implications for the company. We focus on innovation activities, which represent an important channel through which pay dispersion can affect firm performance, and test our predictions by exploring innovative output as a function of executives’ pay dispersion in a panel of US firms. We find that executive pay dispersion acts as a double-edged sword: on the one hand, the higher the dispersion in variable pay, the higher the innovation. On the other hand, the larger the dispersion in fixed pay, the lower the innovation. Results are robust to a number of tests, such as restricting the analysis to executives with direct responsibility for innovation projects and considering individual incentives in the form of cash pay

Réadaptation et psychose : de l’enveloppe soignante à l’enveloppe sociale

International audienceAfter a theoretical reminder of main notions of readjustment, rehabilitation, reintegration, the authors broaden the thought on readjustment from clinical experience near chronic psychotic patients in therapeutic flats.They show how the patient converts his ties with his circle and social world, through a new psychic organization with moments of crisis: the patient must gradually free oneself from “nursing envelope” to invest others envelopes, before being able to integrate a new group which constitute “social envelope”.Après un rappel théorique des notions essentielles de réadaptation, réhabilitation et réinsertion, les auteurs ouvrent la réflexion sur la réadaptation à partir d’une expérience clinique auprès de patients psychotiques chroniques en appartements thérapeutiques. Ils montrent comment le patient réaménage ses liens à son entourage et au monde social, à travers une réorganisation psychique parsemée de moments de crise: le patient doit progressivement se détacher de l’«enveloppe soignante» pour investir des enveloppes substitutives, avant de pouvoir intégrer un nouveau groupe constitutif de l’«enveloppe sociale»

Réadaptation et psychose : de l'enveloppe soignante à l'enveloppe sociale

International audienceAfter a theoretical reminder of main notions of readjustment, rehabilitation, reintegration, the authors broaden the thought on readjustmentfrom clinical experience near chronic psychotic patients in therapeutic flats.They show how the patient converts his tieswith his circle and social world, through a new psychic organization with moments of crisis: the patient must gradually free oneselffrom “nursing envelope” to invest others envelopes, before being able to integrate a new group which constitute “social envelope”.Après un rappel théorique des notions essentielles de réadaptation,réhabilitation et réinsertion,les auteurs ouvrent la réflexion sur la réadaptation à partir d’une expérience clinique auprès de patients psychotiques chroniques en appartements thérapeutiques. Ils montrent comment le patient réaménage ses liens à son entourage et au monde social,à travers une réorganisation psychique par-semée de moments de crise:le patient doit progressivement se détacher de l’«enveloppe soignante» pour investir des enveloppes substitutives,avant de pouvoir intégrer un nouveau groupe constitutif de l’«enveloppe sociale

Solution to the Equations of the Moment Expansions

We develop a formula for matching a Taylor series about the origin and an asymptotic exponential expansion for large values of the coordinate. We test it on the expansion of the generating functions for the moments and connected moments of the Hamiltonian operator. In the former case the formula produces the energies and overlaps for the Rayleigh-Ritz method in the Krylov space. We choose the harmonic oscillator and a strongly anharmonic oscillator as illustrative examples for numerical test. Our results reveal some features of the connected-moments expansion that were overlooked in earlier studies and applications of the approach