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2. Use of E-Learning Functionalities and Standards: The Spanish Case

Author

Llamas-Nistal, M., Caeiro-Rodriguez, M., and Castro, M.

Abstract

This paper shows the results of a survey performed in Spain on the different functionalities of e-learning platforms. This survey was filled in by a group of teachers, experts in engineering education from across Spain, within the scope of the Spanish Chapter of the IEEE Education Society. This paper presents their opinions on several aspects of e-learning functionalities, such as knowledge levels, levels of use, and usefulness, as well as describing the most commonly used platforms. One of the objectives of this work is to create a debate in the international community about the use of e-learning platforms and their main functionalities, the most frequently used standards, the implications for and the levels of support by institutions in their use of e-learning platforms, and in general, their advantages and disadvantages. (Contains 5 tables and 20 figures.)

Published
2011
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3. A Wave-Optics Approach to Paraxial Geometrical Laws Based on Continuity at Boundaries

Author

Linares, J. and Nistal, M. C.

Abstract

We present a derivation of the paraxial geometrical laws starting from a wave-optics approach, in particular by using simple continuity conditions of paraxial spherical waves at boundaries (discontinuities) between optical media. Paraxial geometrical imaging and magnification laws, under refraction and reflection at boundaries, are derived for several instructive cases and without using Fresnel diffraction theory. The primary aim is to provide a complementary insight into the standard axiomatic approach of paraxial geometrical optics and likewise to allow the introduction of some wave imaging concepts, such as the transmittance function, with a notable didactic interest for advanced subjects such as Fourier optics. This approach provides a more homogeneous vision of classical optics in which the use of the optical field continuity conditions at a boundary is a usual requirement as is clearly seen, for example, in the case of the derivation of Fresnel formulas. The work is particularly intended for university physics teachers and pregraduate and first year postgraduate students. (Contains 1 figure.)

Published
2011
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4. Optical Field-Strength Polarization of Two-Mode Single-Photon States

Author

Linares, J., Nistal, M. C., and Barral, D.

Abstract

We present a quantum analysis of two-mode single-photon states based on the probability distributions of the optical field strength (or position quadrature) in order to describe their quantum polarization characteristics, where polarization is understood as a significative confinement of the optical field-strength values on determined regions of the two-mode optical field-strength plane. We will show that the mentioned probability distributions along with the values of quantum Stokes parameters allow us to characterize the polarization of a two-mode single-photon state, in an analogous way to the classical case, and to distinguish conceptually between mixture and partially polarized quantum states; in this way, we propose a simple definition of the quantum polarization degree based on the recent concept of distance measure to an unpolarized distribution, which gives rise to a depolarization degree equivalent to an overlapping between the probability distribution of the quantum state and a non-polarized two-mode Gaussian distribution. The work is particularly intended to university physics teachers and graduate students as well as to physicists and specialists concerned with the issue of optical polarization. (Contains 5 figures.)

Published
2010
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23. Predictors and early warning systems in higher education: a systematic literature review

Author

Martín Liz-Domínguez, Caeiro-Rodríguez, M., Llamas-Nistal, M., and Mikic-Fonte, F.

Subjects
1203.04 Inteligencia Artificial, 1209.03 Análisis de Datos
Abstract

The topic of predictive algorithms is often regarded among the most relevant fields of study within the data analytics discipline. Nowadays, these algorithms are widely used by entrepreneurs and researchers alike, having practical applications in a broad variety of contexts, such as in finance, marketing or healthcare. One of such contexts is the educational field, where the development and implementation of learning technologies led to the birth and popularization of computerbased and blended learning. Consequently, student-related data has become easier to collect. This Research Full Paper presents a literature review on predictive algorithms applied to higher education contexts, with special attention to early warning systems (EWS): tools that are typically used to analyze future risks such as a student failing or dropping a course, and that are able to send alerts to instructors or students themselves before these events can happen. Results of using predictors and EWS in real academic scenarios are also highlighted.

Published
2019

27. Combined surgical and endovascular repair of a ruptured bilateral aortoiliac aneurysm

Author

Moral, L. Riera del, Nistal, M. Gutierrez, Kiuri, S. Stefanov, Alonso, S. Fernandez, Moll, A. Garzon, and Cubas, L. Riera de

Subjects
Aortic aneurysms -- Case studies, Aortic aneurysms -- Diagnosis, Aortic aneurysms -- Care and treatment, Stent (Surgery) -- Usage, Blood vessels -- Surgery, Blood vessels -- Methods, Blood vessels -- Usage, Health
Published
2007

30. Geometric phases in magnetooptic channel waveguide devices

Author

Nistal, M. Concepcion, Linares, Jesus, and Baldomir, Daniel

Subjects
Waveguides -- Research, Magneto-optical devices -- Research, Electromagnetic waves -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

Geometric phases, generated by a coupling process between TE and TM polarizations through anisotropic chiral media - magnetooptic channel waveguides - are determined. In fact, many of the conventional phase and frequency shifters are based on this geometrical effect, nevertheless, the physical origin of these phase factors (spatial and temporal ones) has never been explained. In this work a physical interpretation, based on the topological phases theory, is given. Likewise, an integrated interferometer is proposed for both generating and checking these phases by changing the characteristics of the channel waveguides. The relationship between geometric factors and phase and frequency shifters is shown along the work.

Published
1995

41. Immunohistochemical and quantitative study of interstitial and intratubular Leydig cells in normal men, cryptorchidism, and Klinefelter's syndrome

Author

Regadera, J., Codesal, J., Paniagua, R., Gonzalez-Peramato, P., and Nistal, M.

Subjects
Cryptorchism -- Physiological aspects, Testis -- Abnormalities, Leydig cells -- Abnormalities, Klinefelter's syndrome -- Physiological aspects, Health
Abstract

Cells from the testes of normal men, men with cryptorchidism (CR), and Klinefelter's syndrome (KS) were examined for the presence of testosterone, the hormone associated with maleness. CR is the failure of one or both of the testicles to descend into the scrotum during fetal development. KS is an inherited syndrome affecting the male genital system. Leydig cells are cells of the testes that produce testosterone. Leydig cells can be classified into three groups based on morphology (structure): normal, multivacuolated (containing many vacuoles), and pleomorphic (varied). In normal testes, normal and multivacuolated Leydig cells were found. Testes from CR patients had a decreased number of normal Leydig cells and an increased number of multivacuolated Leydig cells. Testes from KS patients had decreased numbers of normal cells, but increased numbers of multivacuolated and pleomorphic Leydig cells. The number of Leydig cells that contained testosterone was decreased in patients with CR and KS. Multivacuolated Leydig cells contained lower levels of testosterone, compared with normal cells. Pleomorphic Leydig cells did not contain testosterone. Decreased numbers of cells containing testosterone indicate that the cells are not functioning properly. Leydig cells are normally found in the interstitial spaces of the testes. In CR and KS, Leydig cells were also found in the tubules of the testes; these cells contained less testosterone than those in the interstitial spaces. The location of Leydig cells in the tubules indicates that these cells are not functioning properly. (Consumer Summary produced by Reliance Medical Information, Inc.)

Published
1991

42. The syndrome of central hypothyroidism and macroorchidism: IGSF1 controls TRHR and FSHB expression by differential modulation of pituitary TGF beta and Activin pathways

Author

Garcia, M, Barrio, R, Garcia-Lavandeira, M, Garcia-Rendueles, AR, Escudero, A, Diaz-Rodriguez, E, del Blanco, DG, Fernandez, A, de Rijke, Yolanda, Vallespin, E, Nevado, J, Lapunzina, P, Matre, V, Hinkle, PM, Hokken - Koelega, Anita, de Miguel, MP, Cameselle-Teijeiro, JM, Nistal, M, Alvarez, CV, Moreno, JC, Garcia, M, Barrio, R, Garcia-Lavandeira, M, Garcia-Rendueles, AR, Escudero, A, Diaz-Rodriguez, E, del Blanco, DG, Fernandez, A, de Rijke, Yolanda, Vallespin, E, Nevado, J, Lapunzina, P, Matre, V, Hinkle, PM, Hokken - Koelega, Anita, de Miguel, MP, Cameselle-Teijeiro, JM, Nistal, M, Alvarez, CV, and Moreno, JC

Published
2017

43. Datos normativos de las Matrices Progresivas Coloreadas en niños indígenas yaquis

Author

Mercado Ibarra, Santa Magdalena and Fernández Nistal, M. Teresa

Subjects
Matrices Progresivas Escala Coloreada, indígenas yaquis, inteligencia, normas, Matrices Progresivas Escala Coloreada, Yaqui indigenous, inteligencia, normas, Raven's Coloured Progressive Matrices, intelligence, indígenas yaquis, norms
Abstract

Normative data for Raven´s Coloured Progressive Matrices (RCPM) are presented for a Mexican sample of 665 indigenous Yaqui children (Mexico) from 5 to 11.11 years old. The data are compared with the Mexican normative data used at the national level (Méndez y Palacios, 2008). Analysis of the metric properties shows good validity and reliability indices, which proves the test to be a useful tool for assessing nonverbal intelligence of Yaqui children. The comparison of these normative data with national norms shows differences in all age groups, with the Yaqui children scoring lowest. We conclude that there is a need for local standards of the test in this indigenous population to ensure the correct inferences and interpretations about the meaning of the scores., Se presentan datos normativos del Test de Matrices Progresivas Escala Coloreada (MPC) obtenidos de una muestra de 665 niños de la comunidad indígena yaqui (México) entre los 5 y los 11.11 años de edad y los resultados de la comparación de estas normas con el baremo mexicano usado a nivel nacional (Méndez y Palacios, 2008). El análisis de las características métricas del MPC indicó buenos índices de validez y fiabilidad, lo que demuestra que es un instrumento útil para evaluar la inteligencia no verbal de niños de la comunidad yaqui. Los resultados de la comparación entre las normas obtenidas y las nacionales mostraron una ejecución inferior en los niños yaquis detodos los grupos de edad, por lo que se concluye la necesidad de utilizar normas locales de este test en esta población indígena, que aseguren la realización de inferencias e interpretaciones correctas sobre el significado de las puntuaciones que obtienen estos niños.

Published
2014

47. Diagnostic value of the gonadal biopsy in the disorders of sex development

Author

Nistal, M., García-Fernández, E., Mariño-Enríquez, A., Serrano, A., Regadera, J., and González-Peramato, P.

Subjects
endocrine system, Estados intersexuales, Hermafroditismo, Pseudohermafroditismo, Anorquia, Biopsia gonadal, Disgenesia gonadal
Abstract

La información proporcionada por la biopsia testicular en los estados intersexuales es primordial para la identificación, clasificación y detección precoz de neoplasias en estos pacientes. Antes de decidir una determinada opción terapéutica, los datos del estudio histológico de la biopsia gonadal deberán ser evaluados junto con los datos clínicos, genéticos, hormonales y moleculares. La diferenciación sexual es el resultado de complejos mecanismos genéticos y endocrinos, por ello, en el presente trabajo se revisan en primer lugar los acontecimientos que ocurren en el desarrollo embrionario de las gónadas, atendiendo a los mecanismos genéticos implicados en la determinación sexual y en la diferenciación testicular y del tracto urogenital. En segundo lugar se revisan los distintos tipos de gónadas observadas en los desórdenes del desarrollo sexual (síndromes de regresión testicular, cintilla fibrosa, disgenesia testicular, cintilla testículo, ovotestes, testículos microscópicamente normales y ovario), haciendo énfasis en los datos histológicos presentes en cada uno de ellos y en los datos diferenciales que permiten al patólogo distinguir unos desórdenes de otros, junto con la integración de los datos clínicos, genéticos hormonales y moleculares de cada una de estas situaciones. En tercer lugar se considera la incidencia de neoplasias, tanto en las diferentes situaciones clásicamente llamadas disgenesia gonadal, como de pseudohermafroditismos masculinos y hermafroditismo verdadero. Por último, se comentan las limitaciones de la biopsia gonadal que pueden impedir que el patólogo llegue a un diagnóstico preciso de un desórden del desarrollo sexual. The gonadal biopsy provides essential information for the identification, classification and early detection of neoplasias in patients with disorders of sex development. Histopathological findings in these cases must be analysed together with clinical, hormonal, genetic and molecular information before deciding a therapeutic option. Sexual differentiation is the result of multiple and complex genetic and endocrinal mechanisms; therefore, we first present the events taking place during gonadal embryonic development, focusing on the genetic mechanisms involved in sexual determination and the differentiation of the testis and the urogenital tract. In second place, we describe the different gonads in the intersexual states -in testicular regression syndrome, fibrous streak, testicular dysgenesis, streak testes, ovotestes and microscopically normal testes and ovaries-, highlighting the histological features and the differential findings that allow the pathologist to distinguish between these entities with the aid of clinical, genetic, hormonal and molecular information that are characteristic for each situation. In third place, we studied the incidence of neoplasias in gonadal dysgenesis, male pseudohermaphroditism and true hermaphroditism. Finally, we discuss the limitations of gonadal biopsy to achieve a correct diagnosis in the disorders of sex development.

Published
2007

50. Conceptualization of night and day. A cross-cultural study

Author

Fernández Nistal, M. Teresa

Subjects
conceptions of day and night, cross-cultural differences, Knowledge construction, diferencias transculturales, construcción del conocimiento, concepciones del dia y la noche
Abstract

The development of the understanding of the concept of day andnight is studied in children from Barcelona and from the Karaja tribe in Brazil, of several ages. Different conceptions of this understanding are identified in the groups and compared with each other. The instruments used is a semi-structured interview, administered individually. A qualitative analysis of the answers to this interview identifiesfive conceptions in the Barcelona children andfive in the Karaja children, which are classified in four categories: (a) conceptions based on apparent perceptions, (b)conceptions that articulate data on the apparent perception with cultural knowledge, (c) conceptions that are misinterpretations o f cultural knowledge and (d) scientijic conceptions. The distribution of the frequency of the two groups in the different conceptions indicates that a development of this knowledge exists, and is age-related. Results of the cross-cultural comparison reveal that the conceptions are fairly homogeneous, which is explained by a process of common construction and by the access of bothgroups to a scientific explanation. The differences draw attention to the determination of the apparent perception in the initial construction of this knowledge., Se estudia el desarrollo del conocimiento del dia y la noche en niños de Barcelona e indigenas karajás (Brasil) de diferentes edades, se identifican las distintas concepciones sobre este conocimiento en ambos grupos de participantes y se comparan entre sí. El instrumento utilizado es una entrevista semiestructurada de aplicación individual. Un análisis cualitativo de las respuestas a esta entrevista permite identificar cincoconcepciones en los niños de Barcelona y cinco en los participantes karajás, que se clasifican en cuatro categorías: (a) concepciones basadas en la percepción aparente; (b) concepciones que articulan datos de la percepción aparente con conocimientos culturales; (e) concepciones que son interpretaciones erróneas de los conocimientos culturales y (d) concepción cientfica. La distribución de frecuencias de ambos grupos de participantes en las distintas concepciones indica que existe un desarrollo de este conocimiento relacionado con la edad. Los resultados de la comparacióntranscultural revelan bastante homogeneidad en las concepciones que se explica por un proceso de construcción común y por el acceso de ambos grupos de participantes a la explicación científca. Las diferencias afirman la determinación de la percepción aparente en la construcción inicial de este conocimiento.

Published
2004

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