Measuring the effective focal length and shape factor of a thick lens using a microscope

The optical power of a thick spherical lens and its Coddington shape factor are essential magnitudes that characterize its image quality. Here, we propose an experimental procedure and apparatus that allow accurate determination of those magnitudes for any spherical lens from geometrical measurements. The performance of the technique and the used instruments are simple since it only requires a microscope and an optical mouse. The propose overcomes the drawbacks of other devices that need of the refractive index or may damage the lens surfaces, like spherometers, and provides similar results to those from commercial lensmeters.Authors thank the University of Alicante for the funds (GITE-09003-UA). This work was supported by the “Vicerrectorado de Tecnología e Innovación Educativa” of the University of Alicante (Spain) and under the project GV/2013/009

Analysis of the Learning Process through Eye Tracking Technology and Feature Selection Techniques

In recent decades, the use of technological resources such as the eye tracking methodology is providing cognitive researchers with important tools to better understand the learning process. However, the interpretation of the metrics requires the use of supervised and unsupervised learning techniques. The main goal of this study was to analyse the results obtained with the eye tracking methodology by applying statistical tests and supervised and unsupervised machine learning techniques, and to contrast the effectiveness of each one. The parameters of fixations, saccades, blinks and scan path, and the results in a puzzle task were found. The statistical study concluded that no significant differences were found between participants in solving the crossword puzzle task; significant differences were only detected in the parameters saccade amplitude minimum and saccade velocity minimum. On the other hand, this study, with supervised machine learning techniques, provided possible features for analysis, some of them different from those used in the statistical study. Regarding the clustering techniques, a good fit was found between the algorithms used (k-means ++, fuzzy k-means and DBSCAN). These algorithms provided the learning profile of the participants in three types (students over 50 years old; and students and teachers under 50 years of age). Therefore, the use of both types of data analysis is considered complementary.European Project “Self-Regulated Learning in SmartArt” 2019-1-ES01-KA204-065615

Phytoextraction of heavy metals from mine soils using hyperaccumulator plants.

Phytoextraction is an environmental-friendly and cost-effective technology that uses metal hyperaccumulator plants to remove heavy metals from soils. The metals are absorbed by the roots, transported and accumulated in the aerial parts of the plants, which can be harvested and eliminated. The aim of this work was to study some hyperaccumulator species that could be useful to decontaminate mine soils and also to investigate the bioavailability and uptake of these metals by plants with the addition of organic amendments. Pot experiments were performed with soil samples collected from two mining areas in the north of Madrid, where there was an intense mining activity more than 50 years ago. Three species (Thlaspi arvense, Brassica juncea and Atriplex halimus) were grown under controlled conditions in pots filled with contaminated soils mixed with 0 Mg, 30 Mg and 60 Mg per hectare of two different organic amendments: a commercial compost made of pine bark, peat and wood fiber and other made of horse and sheep manure and wood fiber. Plants were harvested at the end of their crop cycle and were digested in order to measure metal concentration (Zn, Cu and Cd) in roots and shoots. Highest plant metal concentration was observed in pots treated with pine bark amendment and with pure soil due to an increase in metal bioavailability with decreasing pH. Also in those treatments the total plant biomass was lower, even some plants could not germinate. On the contrary, there was a lower metal concentration in plant tissues of pots with manure because its higher pH whereas plant growth was significantly larger so there was an incresing amount of metals removed from soil by plants. Comparing the three species results indicate a higher total metal uptake in A. halimus than B. juncea and T. arvense. In conclusion, results show that pH affects metal bioavailability and uptake by hyperaccumulator plants. Addition of organic amendments could be a successful technique for stabilization of metals in contaminated soils

Complete algorithm for the calculation light patterns inside the ocular media

Realistic mathematical models are of great importance for studying the optical performance of the human eye. Light propagation algorithms provide robust methods to calculate field distributions inside a homogeneous medium, and thus they can be applied to the study of light patterns inside the anterior and posterior chambers of the eye. Dealing with real eyes implies using very short propagation distances together with highly refractive power surfaces. Thus, the general solutions of the field equation are used instead of paraxial Fresnel solutions. Conditions of application and sampling conditions of the method are clearly stated here. Numerical evaluation of the different refractive surfaces is also analysed. The main result is that a complete algorithm to obtain light patterns at any axial distance inside the eye is proposed. The method uses real corneal measures and axial distances together with crystalline models. Statistical results and individual predictions show the validity of the model. Application of the method is illustrated with the study of a bifocal intraocular lens.This work has been partially supported by the Conselleria de Cultura, Educació i Esport of the Generalitat Valenciana, through project GV04A/578

Competencias Tutoriales en los Programas de Postgrado: Una Mirada desde la Experiencia Venezolana

La Tutoría representa un componente fundamental en los Programas de Postgrado; su acción trasciende lo meramente académico y consolida la formación en investigación de sus participantes, traduciéndose en calidad de producción intelectual y progreso social. El propósito de la investigación de tipo documental es proporcionar aportes teóricos referenciales, relacionados con los estudios de Postgrado en Venezuela, así como abordar la concepción, caracterización, tipología y operacionalización de la competencia tutorial. Este abordaje referencial forma parte de un estudio de mayor alcance denominado Competencias Tutoriales para la producción de textos académicos en el nivel de postgrado. Es así como, desde el ejercicio reflexivo, surge un conjunto de consideraciones sobre aspectos trascendentales de la competencia tutorial en la que prevalece la imprescindible formación en el plano investigativo. Desde esta visión se espera promover procesos reflexivos tendentes a generar mayor interés por programar acciones significativas en esta área la cual precisa de constante revisión sistemática y autorreflexión

Effect of high pressure homogenization and heat treatment on physical properties and stability of almond and hazelnut milks

[EN] The effect of high pressure homogenisation (HPH) and heat treatments on physicochemical properties and physical stability of almond and hazelnut milks was studied. Vegetable milks were obtained and homogenised by applying 62, 103 and 172 MPa (MF1, MF2 and MF3, respectively). Untreated and MF3 samples were also submitted to two different heat treatments (85ºC/30 min (LH) or 121ºC/15 min (HH)). Physical and structural properties of the products were greatly affected by heat treatments and HPH. In almond milk, homogenised samples showed a significant reduction in particle size, which turned from bimodal and polydisperse to monodisperse distributions. Particle surface charge, clarity and Whiteness Index were increased and physical stability of samples was improved, without affecting either viscosity or protein stability. Hazelnut beverages showed similar trends, but HPH notably increased their viscosity while change their rheological behaviour, which suggested changes in protein conformation. HH treatments caused an increment of particle size due to the formation oil droplet-protein body clusters, associated with protein denaturation. Samples submitted to the combined treatment MF3 and LH showed the greatest stability.The authors acknowledge the financial support provided by Universitat Politecnica de Valencia (Valencia, Spain) for the project (PAID 05-11-2740). Author N. Bernat appreciates the Conselleria de Eduacion of Valencia (Spain) for a FPI Grant (Programa VALi + d para investigadores en formacion. ACIF/2011).Bernat Pérez, N.; Cháfer Nácher, MT.; Rodríguez García, J.; Chiralt, A.; González Martínez, MC. (2015). Effect of high pressure homogenization and heat treatment on physical properties and stability of almond and hazelnut milks. Food Science and Technology. 62:488-496. https://doi.org/10.1016/j.lwt.2014.10.045S4884966

Determinación de la aberración cromática longitudinal en ojos humanos

En este trabajo, el Grupo de Óptica y Ciencias de la Visión de la Universidad de Alicante muestra los últimos resultados obtenidos en su línea de trabajo. Los autores calculan la aberración cromática longitudinal mediante el cálculo de patrones de luz propagados a través del ojo encontrando dichas distribuciones, tanto en amplitud como en fase, en un plano cualquiera del interior del ojo humano del cual se conocen su topografía corneal y sus medidas biométricas. Se ha modelado la dependencia de todos los medios oculares con la longitud de onda siguiendo la ecuación de Cauchy. Los autores han realizado el estudio de diez sujetos y han comparado los resultados con medidas reales de aberración cromática, mostrando la concordancia del cálculo numérico. Como muestra de la capacidad de la técnica utilizada, se ha aplicado el método al estudio de la aberración cromática de un queratocono.In this communication the authors have determined the longitudinal chromatic aberration using an algorithm for free space propagated pattern calculation. From topographical and biometric data, the algorithm is capable of provide amplitude and phase distribution of the field at any distance inside the eye. The wavelength dependence of all ocular media has been modelled through the Cauchy formula. Results from the study of ten subjects are compared with real measures of the chromatic aberration, showing a good agreement with numerical calculations. The capabilities of the technique have been demonstrated by applying the method to the study of the chromatic aberration of a keratoconus.Este trabajo ha sido financiado por la Conselleria de Cultura, Educació i Esport de la Generalitat Valenciana, a través del proyecto GV04A/578

IV Edición. Colaboración con centros de secundaria para la formación experimental de alumnos de bachillerato

La “Red para la colaboración con centros de secundaria para la formación experimental de alumnos de bachillerato” ha llevado a cabo este año su quinta edición. La línea de actuación prioritaria se mantiene siendo el fomento del intercambio de experiencias en diferentes campos del conocimiento científico dirigidas al alumnado que cursa Bachillerato o estudios de Secundaria. En la edición de este curso hemos recibido en nuestros laboratorios a 233 alumnos procedentes de 11 centros de la provincia de Alicante para la realización de diferentes prácticas. El periodo elegido, como viene siendo habitual han sido los meses de Enero y Febrero, durante el periodo de elaboración de exámenes, no lectivo que tiene la Universidad de Alicante para los alumnos de todas las titulaciones de grado. en las que los alumnos han sido los verdaderos protagonistas. Esto significaría que en las 5 ediciones de nuestra red hemos recibido en nuestros laboratorios en total a 858 alumnos de Bachiller y de de 4º año de educación secundaria obligatoria (ESO). Estudiantes que han realizado bajo nuestra supervisión las prácticas de laboratorio que previamente habían sido ofertadas a sus centros. En todas las ediciones, los resultados obtenidos han sido plenamente satisfactorios tanto para los alumnos como para todos los profesores integrantes de la Red. Pensamos que es tiempo de reunir y reflexionar sobre todo el trabajo realizado

Nursing Students’ Perceived Satisfaction with Flipped Learning Experiences: A Mixed-Methods Study

Nowadays, technological teaching tools, such as virtual labs, have become essential, especially in nursing degrees. These resources help implement practical learning based on selfregulation and it is important to know how satisfied students are with them. This means it is important to study students’ perceived satisfaction with virtual labs in flipped learning experiences, which was the general objective of the present study. The aims of the study were: (1) to determine whether there were significant differences in nursing students’ perceived levels of satisfaction according to the type of subject or gender; (2) to ascertain what strengths and weaknesses nursing students perceived about using virtual labs; and (3) to determine the kinds of feelings (positive, negative or neutral) nursing students had using virtual labs. A mixed research methodology was applied, with a sample of 222 undergraduate nursing students at Burgos University (Spain). There were significant differences in the satisfaction perceived by students depending on the subject. Students reported medium-high satisfaction with virtual labs, although they did note that digital skills are needed to use them and suggested incorporating intelligent assistants. Virtual labs seem to be effective, although further studies are needed.This work was supported by the Vice-Rectorate for Teaching Staff from University of Burgos (Spain) (grant numbers TVLab_01, 3/02/21) and the Ministry of Science and Innovation of Spain Projects I+D+i Research Challenges (grant number PID2020-117111RB-I00, 01/01/21)

Lectoescritura: Más allá de una construcción escolar

PublishedEl siguiente capítulo presenta de forma clara los resultados obtenidos en la investigación “El texto narrativo y la construcción de habilidades de lecto-escritura en el nivel preescolar”, teniendo como referencia las etapas y proceso de adquisición del lenguaje oral y escrito que tienen los niños, teniendo en cuenta diferentes perspectivas pedagógicas, donde se reafirma que la competencia comunicativa está lejos de ser un aprendizaje mecánico y repetitivo como fuente de aprendizaje. El objetivo central de la mencionada investigación fue identificar las habilidades de lectura y el proceso de escritura a través del texto narrativo en niños de preescolar en la ciudad de Cali. El desarrollo de este proyecto permitió ver a cada niño como un sujeto diferente de los demás, autónomo, que se comunica con otros, que apela a su responsabilidad de escribir como él considera que está bien, que busca soluciones, que propone ideas