De las escuelas rurales: el ejemplo de la Escuela de Barxell "Santa Rosa de Lima", Alcoy

El presente texto se ha elaborado pensando en objetivos aparentemente diferentes, pero en conjunto interrelacionados: El primer objetivo era reconstruir la historia de una escuela rural, como otras muchas, unitaria y mixta. Estas escuelas rurales no han atraido la atención de la sociedad contemporánea, de sus investigadores y sus medios de comunicación, y difícilmente realizaran un homenaje sobre sus bodas de plata, oro, etc., como ocurre en muchas de las escuelas urbanas. Y no podrán hacerlo porque la sociedad en la que se crearon, desarrollaron y finalmente desaparecieron, igualmente, se ha extinguido. No se trata, como es normal, de una desaparición relacionada sólo con el paso del tiempo, tempus fugit. Es obvio que el paso del tiempo ha influido, pero también ha sido decisiva la transformación de una sociedad rural en otra urbana. Esta transición cronológicamente se sitúa en la provincia de Alicante entre 1960 y 1970, con el “take off” o despegue industrial, y en otros casos con el desarrollo turístico. Fue especialmente en la década de los setenta, coincidiendo con la crisis económica y política cuando se cerraron muchas escuelas rurales. Como elemento decisivo influyó un criterio económico y no educativo o social. La concentración de los niños de población rural en un centro urbano era más barato, incluso si se tenía que pagar los gastos de transporte y comedor escolar. Con el tiempo, este criterio económico que podemos calificar de fordista, se ha manifestado como problemático e inadecuado en diferentes actividades, sin que su cuestionamiento en el mundo de la educación se haya generalizado. Es cierto, que en la educación es esencial la socialización del niño y el que exista un cierto número de niños en la escuela, pero esta razón, o no ha estado presente, o no se ha explicitado lo suficiente. El segundo objetivo era reconstruir la historia de una escuela rural, a partir de fuentes documentales, preferentemente no conservadas en archivos oficiales, sino a partir de la experiencia de sus protagonistas, alumnos, maestros, padres, mediante documentos conservados en sus casas como notas, cuadernos, libros de texto, fotografías, etc. Es decir, mediante los nuevos métodos de investigación que se potenciaron a partir de la renovación que supuso la Escuela de los Annales. Esta historia no es la historia “oficial” de grandes personajes, ilustres pedagogos, reconocidos docentes o avanzados investigadores. Esta historia narra un determinado aspecto de la vida cotidiana de muchas personas que hacen historia, pero de la que los investigadores, en muchas ocasiones, hacen caso omiso. El tercer objetivo era el de contribuir a la reconstrucción de la historia de la escuela rural. El alcance de este objetivo no se limita al “caso” de la escuela, sino que pretende servir de modelo y estímulo para que muchos docentes jubilados, familiares, estudiantes, vean este trabajo como ejemplo para recuperar la historia de sus escuelas y con ellas la de una sociedad cuyo modelo ha sido hasta fechas recientes el más extenso. El investigador que decida seguir esta senda encontrará un amplio apoyo social. Es grande la predisposición de los implicados en colaborar en la recuperación de la memoria colectiva. La inicial dificultad de carecer del clásico archivo público no suele ser un obstáculo. La investigación se desarrolla a través de un circuito en el que establecido el primer contacto, éste te facilita otro y al final se dispone de una estructura piramidal de contactos, que permiten obtener una información diversa y compleja. La amplitud de la documentación facilitada puede generar el problema de cómo tener que elegir para evitar la divagación. En la investigación afloran cuestiones etnográficas, sociales y culturales, que aunque interesantes y que permiten conocer mejor la sociedad en la que se asienta la escuela, en ocasiones llegan a obstruir el cumplimiento de nuestro propósito. Por esta razón conviene tener en todo momento clara la intención que se persigue y seleccionar aquello que se considere más directamente relacionado con el tema.

Integration of different models in the design of chemical processes: Application to the design of a power plant

With advances in the synthesis and design of chemical processes there is an increasing need for more complex mathematical models with which to screen the alternatives that constitute accurate and reliable process models. Despite the wide availability of sophisticated tools for simulation, optimization and synthesis of chemical processes, the user is frequently interested in using the ‘best available model’. However, in practice, these models are usually little more than a black box with a rigid input–output structure. In this paper we propose to tackle all these models using generalized disjunctive programming to capture the numerical characteristics of each model (in equation form, modular, noisy, etc.) and to deal with each of them according to their individual characteristics. The result is a hybrid modular–equation based approach that allows synthesizing complex processes using different models in a robust and reliable way. The capabilities of the proposed approach are discussed with a case study: the design of a utility system power plant that has been decomposed into its constitutive elements, each treated differently numerically. And finally, numerical results and conclusions are presented.

Minimizing the IOL Power Error Induced by Keratometric Power

Purpose. To evaluate theoretically in normal eyes the influence on IOL power (PIOL) calculation of the use of a keratometric index (nk) and to analyze and validate preliminarily the use of an adjusted keratometric index (nkadj) in the IOL power calculation (PIOLadj). Methods. A model of variable keratometric index (nkadj) for corneal power calculation (Pc) was used for IOL power calculation (named PIOLadj). Theoretical differences ($PIOL) between the new proposed formula (PIOLadj) and which is obtained through Gaussian optics (PIOL Gauss) were determined using Gullstrand and Le Grand eye models. The proposed new formula for IOL power calculation (PIOLadj) was prevalidated clinically in 81 eyes of 81 candidates for corneal refractive surgery and compared with Haigis, HofferQ, Holladay, and SRK/T formulas. Results. A theoretical PIOL underestimation greater than 0.5 diopters was present in most of the cases when nk = 1.3375 was used. If nkadj was used for Pc calculation, a maximal calculated error in $PIOL of T0.5 diopters at corneal vertex in most cases was observed independently from the eye model, r1c, and the desired postoperative refraction. The use of nkadj in IOL power calculation (PIOLadj) could be valid with effective lens position optimization nondependent of the corneal power. Conclusions. The use of a single value of nk for Pc calculation can lead to significant errors in PIOL calculation that may explain some IOL power overestimations with conventional formulas. These inaccuracies can be minimized by using the new PIOLadj based on the algorithm of nkadj.

Logic-Based Outer-Approximation Algorithm for Solving Discrete-Continuous Dynamic Optimization Problems

We present an extension of the logic outer-approximation algorithm for dealing with disjunctive discrete-continuous optimal control problems whose dynamic behavior is modeled in terms of differential-algebraic equations. Although the proposed algorithm can be applied to a wide variety of discrete-continuous optimal control problems, we are mainly interested in problems where disjunctions are also present. Disjunctions are included to take into account only certain parts of the underlying model which become relevant under some processing conditions. By doing so the numerical robustness of the optimization algorithm improves since those parts of the model that are not active are discarded leading to a reduced size problem and avoiding potential model singularities. We test the proposed algorithm using three examples of different complex dynamic behavior. In all the case studies the number of iterations and the computational effort required to obtain the optimal solutions is modest and the solutions are relatively easy to find.

Error induced by the estimation of the corneal power and the effective lens position with a rotationally asymmetric refractive multifocal intraocular lens

AIM: To evaluate the prediction error in intraocular lens (IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position (ELP). METHODS: Retrospective study including a total of 25 eyes of 13 patients (age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL (Oculentis GmbH, Germany). In all cases, an adjusted IOL power (PIOLadj) was calculated based on Gaussian optics using a variable keratometric index value (nkadj) for the estimation of the corneal power (Pkadj) and on a new value for ELP (ELPadj) obtained by multiple regression analysis. This PIOLadj was compared with the IOL power implanted (PIOLReal) and the value proposed by three conventional formulas (Haigis, Hoffer Q and Holladay). RESULTS: PIOLReal was not significantly different than PIOLadj and Holladay IOL power (P>0.05). In the Bland and Altman analysis, PIOLadj showed lower mean difference (-0.07 D) and limits of agreement (of 1.47 and -1.61 D) when compared to PIOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELPadj was significantly lower than ELP calculated with other conventional formulas (P<0.01) and was found to be dependent on axial length, anterior chamber depth and Pkadj. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing the keratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.

Positional accommodative intraocular lens power error induced by the estimation of the corneal power and the effective lens position

Purpose: To evaluate the predictability of the refractive correction achieved with a positional accommodating intraocular lenses (IOL) and to develop a potential optimization of it by minimizing the error associated with the keratometric estimation of the corneal power and by developing a predictive formula for the effective lens position (ELP). Materials and Methods: Clinical data from 25 eyes of 14 patients (age range, 52–77 years) and undergoing cataract surgery with implantation of the accommodating IOL Crystalens HD (Bausch and Lomb) were retrospectively reviewed. In all cases, the calculation of an adjusted IOL power (PIOLadj) based on Gaussian optics considering the residual refractive error was done using a variable keratometric index value (nkadj) for corneal power estimation with and without using an estimation algorithm for ELP obtained by multiple regression analysis (ELPadj). PIOLadj was compared to the real IOL power implanted (PIOLReal, calculated with the SRK-T formula) and also to the values estimated by the Haigis, HofferQ, and Holladay I formulas. Results: No statistically significant differences were found between PIOLReal and PIOLadj when ELPadj was used (P = 0.10), with a range of agreement between calculations of 1.23 D. In contrast, PIOLReal was significantly higher when compared to PIOLadj without using ELPadj and also compared to the values estimated by the other formulas. Conclusions: Predictable refractive outcomes can be obtained with the accommodating IOL Crystalens HD using a variable keratometric index for corneal power estimation and by estimating ELP with an algorithm dependent on anatomical factors and age.

Optimization of test and maintenance of ageing components consisting of multiple items and addressing effectiveness

There are many models in the literature that have been proposed in the last decades aimed at assessing the reliability, availability and maintainability (RAM) of safety equipment, many of them with a focus on their use to assess the risk level of a technological system or to search for appropriate design and/or surveillance and maintenance policies in order to assure that an optimum level of RAM of safety systems is kept during all the plant operational life. This paper proposes a new approach for RAM modelling that accounts for equipment ageing and maintenance and testing effectiveness of equipment consisting of multiple items in an integrated manner. This model is then used to perform the simultaneous optimization of testing and maintenance for ageing equipment consisting of multiple items. An example of application is provided, which considers a simplified High Pressure Injection System (HPIS) of a typical Power Water Reactor (PWR). Basically, this system consists of motor driven pumps (MDP) and motor operated valves (MOV), where both types of components consists of two items each. These components present different failure and cause modes and behaviours, and they also undertake complex test and maintenance activities depending on the item involved. The results of the example of application demonstrate that the optimization algorithm provide the best solutions when the optimization problem is formulated and solved considering full flexibility in the implementation of testing and maintenance activities taking part of such an integrated RAM model.