Polar optical phonons in core-shell semiconductor nanowires

We obtain the the long-wavelength polar optical vibrational modes of semiconductor core-shell nanowires by means of a phenomenological continuum model. A basis for the space of solutions is derived, and by applying the appropriate boundary conditions, the transcendental equations for the coupled and uncoupled modes are attained. Our results are applied to the study of the GaAs-GaP core-shell nanowire, for which we calculate numerically the polar optical modes, analyzing the role of strain in the vibrational properties of this nanosystem

Un nuevo tratamiento para las epístaxis de la enfermedad de Rendu-Osler-Weber ó telangiectasia hemorrágica hereditaria (HHT).

Hereditary Haemorrhagic Telangiectasia or Rendu-Osler-Weber syndrome is an autosomal dominant vascular rare disease whose clinical manifestations are mucocutaneous and gastrointestinal telangiectases and localized arteriovenous malformations in lung, brain and liver. Epistaxis, due to the telangiectases on the nasal mucosa, is the most frequent clinical manifestation of this syndrome leading in many cases to severe impairment of the quality of life in the patients.Several treatments have been used to reduce epistaxis, but none has been completely effective. The polydocanol (Aethoxysklerol ®) in submucosa or subpericondric injection was first presented for us in 2000, with very good results.After more than fifteen years using the polydocanol in submucosa injection in almost one hundred patients and over 500 injections, we have confirmed that over 95 % of these patients improved their nose bleeds without important side effects.La Enfermedad de Rendu-Osler-Weber, o Telangiectasia Hemorrágica Hereditaria es una rara enfermedad que se transmite con carácter autonómico dominante y que se manifiesta clínicamente con telangiectasias mucocutáneas y gastrointestinales, además de malformaciones arteriovenosas en pulmón, cerebro e hígado.Las hemorragias nasales o epístaxis provocadas por estas telangiectasias son la manifestación más conocida de esta enfermedad, produciendo en muchos casos, por su frecuencia e intensidad, un importante deterioro en la calidad de vida de estos enfermos. Se han utilizado múltiples tratamientos para disminuir las epístaxis, pero ninguno ha sido completamente eficaz. En el año 2000, nosotros presentamos un nuevo tratamiento, inyectando Polidocanol (Etoxisclerol ®) por via submucosa o subpericondral; fuimos los primeros en usarlo en el mundo y los resultados han sido excelentes.Después de más de 15 años usando el polidocanol por esta vía en casi 100 pacientes y con más de 500 infiltraciones, confirmamos que más del 95 % de los pacientes mejoran de sus epístaxis, no habiendo observado ningún efecto secundario importante

Propagación de luz en medios turbulentos

The study of phenomena occurring in a turbulent fluid has been successively improved during the last 40 years. Speci cally, the concentration of a substance advected by the turbulence has received most of the attention, for it covers a wide range of natural and engineering settings: heat transport, dye di usion, microscopic organism movements, etc. These substances are described by scalar elds with a negligible back-e ect on the flow; thus, they are called passive scalar elds. The turbulent refractive index also belongs to this class; this is not a novelty (?). The temperature is a passive scalar eld whenever it produces buoyancy forces smaller than the inertial stresses driving the flow, and a direct calculation shows that its fluctuations are proportional to those of the index. Our interest in lightwave propagation through turbulent media must start here then. That is, we have to comprehend the media before attempt a description of the propagation itself. In the forthcoming sections we will study the dynamics and stochastic properties of passive scalars, and eventually propose models for the refractive index.Facultad de Ciencias Exacta

Brain Music : Sistema generativo para la creación de música simbólica a partir de respuestas neuronales afectivas

gráficas, tablasEsta tesis de maestría presenta una metodología de aprendizaje profundo multimodal innovadora que fusiona un modelo de clasificación de emociones con un generador musical, con el propósito de crear música a partir de señales de electroencefalografía, profundizando así en la interconexión entre emociones y música. Los resultados alcanzan tres objetivos específicos: Primero, ya que el rendimiento de los sistemas interfaz cerebro-computadora varía considerablemente entre diferentes sujetos, se introduce un enfoque basado en la transferencia de conocimiento entre sujetos para mejorar el rendimiento de individuos con dificultades en sistemas de interfaz cerebro-computadora basados en el paradigma de imaginación motora. Este enfoque combina datos de EEG etiquetados con datos estructurados, como cuestionarios psicológicos, mediante un método de "Kernel Matching CKA". Utilizamos una red neuronal profunda (Deep&Wide) para la clasificación de la imaginación motora. Los resultados destacan su potencial para mejorar las habilidades motoras en interfaces cerebro-computadora. Segundo, proponemos una técnica innovadora llamada "Labeled Correlation Alignment"(LCA) para sonificar respuestas neurales a estímulos representados en datos no estructurados, como música afectiva. Esto genera características musicales basadas en la actividad cerebral inducida por las emociones. LCA aborda la variabilidad entre sujetos y dentro de sujetos mediante el análisis de correlación, lo que permite la creación de envolventes acústicos y la distinción entre diferente información sonora. Esto convierte a LCA en una herramienta prometedora para interpretar la actividad neuronal y su reacción a estímulos auditivos. Finalmente, en otro capítulo, desarrollamos una metodología de aprendizaje profundo de extremo a extremo para generar contenido musical MIDI (datos simbólicos) a partir de señales de actividad cerebral inducidas por música con etiquetas afectivas. Esta metodología abarca el preprocesamiento de datos, el entrenamiento de modelos de extracción de características y un proceso de emparejamiento de características mediante Deep Centered Kernel Alignment, lo que permite la generación de música a partir de señales EEG. En conjunto, estos logros representan avances significativos en la comprensión de la relación entre emociones y música, así como en la aplicación de la inteligencia artificial en la generación musical a partir de señales cerebrales. Ofrecen nuevas perspectivas y herramientas para la creación musical y la investigación en neurociencia emocional. Para llevar a cabo nuestros experimentos, utilizamos bases de datos públicas como GigaScience, Affective Music Listening y Deap Dataset (Texto tomado de la fuente)This master’s thesis presents an innovative multimodal deep learning methodology that combines an emotion classification model with a music generator, aimed at creating music from electroencephalography (EEG) signals, thus delving into the interplay between emotions and music. The results achieve three specific objectives: First, since the performance of brain-computer interface systems varies significantly among different subjects, an approach based on knowledge transfer among subjects is introduced to enhance the performance of individuals facing challenges in motor imagery-based brain-computer interface systems. This approach combines labeled EEG data with structured information, such as psychological questionnaires, through a "Kernel Matching CKA"method. We employ a deep neural network (Deep&Wide) for motor imagery classification. The results underscore its potential to enhance motor skills in brain-computer interfaces. Second, we propose an innovative technique called "Labeled Correlation Alignment"(LCA) to sonify neural responses to stimuli represented in unstructured data, such as affective music. This generates musical features based on emotion-induced brain activity. LCA addresses variability among subjects and within subjects through correlation analysis, enabling the creation of acoustic envelopes and the distinction of different sound information. This makes LCA a promising tool for interpreting neural activity and its response to auditory stimuli. Finally, in another chapter, we develop an end-to-end deep learning methodology for generating MIDI music content (symbolic data) from EEG signals induced by affectively labeled music. This methodology encompasses data preprocessing, feature extraction model training, and a feature matching process using Deep Centered Kernel Alignment, enabling music generation from EEG signals. Together, these achievements represent significant advances in understanding the relationship between emotions and music, as well as in the application of artificial intelligence in musical generation from brain signals. They offer new perspectives and tools for musical creation and research in emotional neuroscience. To conduct our experiments, we utilized public databases such as GigaScience, Affective Music Listening and Deap DatasetMaestríaMagíster en Ingeniería - Automatización IndustrialInvestigación en Aprendizaje Profundo y señales BiológicasEléctrica, Electrónica, Automatización Y Telecomunicaciones.Sede Manizale

Video Flashcards, a strategy for the development of communication skills in vocabulary and pronunciation in a third grade English Class.

Los nuevos métodos de enseñanza se centran en el uso de herramientas que son efectivas, como las flashcards, que a lo largo de los años han demostrado ser un método excelente para enseñar inglés como lengua extranjera y pueden adaptarse a las nuevas tecnologías a través de plataformas digitales. Por otro lado, los estudiantes actuales tienen una gran afinidad con la tecnología y los medios audiovisuales, por esta razón surge la idea de crear una nueva herramienta pedagógica: las Video Flahcards, que une los dos conceptos: flashcards y videos. Lo que se busca con este proyecto aplicado es unir dos métodos que puedan llevarnos a un aprendizaje significativo del inglés como idioma extranjero: la eficiencia de las flashcards para memorizar conceptos y el video que nos brinda la posibilidad de aprender la pronunciación. Se demostrará a través de un análisis cuantitativo que esta herramienta pedagógica es bien aceptada por los estudiantes como un nuevo método de aprendizaje. El proyecto consiste en la realización de material didáctico llamado Video Flashcards, elaborado en material tradicional y también a través de una plataforma digital. Esta herramienta la realizan los propios alumnos con la ayuda de su maestro y, como consecuencia, cuando la realizan los propios alumnos, genera mucho más interés en esta actividad y ayuda a adquirir un aprendizaje significativo.The new teaching methods focus on the use of effective tools, such as flashcards, which over the years have proven to be an excellent method of teaching English as a foreign language and can be adapted to new technologies through digital platforms. On the other hand, current students have a great affinity with technology and audiovisual media, for this reason the idea arises to create a new pedagogical tool: Video Flahcards, which unites the two concepts: flashcards and videos. What is sought with this applied project is to unite two methods that can lead us to a significant learning of English as a foreign language: the efficiency of flashcards to memorize concepts and the video that gives us the possibility of learning pronunciation. It will be demonstrated through a quantitative analysis that this pedagogical tool is well accepted by students as a new learning method. The project consists in the realization of didactic material called Video Flashcards, elaborated in traditional material and also through a digital platform. This tool is carried out by the students themselves with the help of their teacher and, as a consequence, when they are carried out by the students themselves, it generates much more interest in this activity and helps to acquire significant learning

Multiscale permutation entropy analysis of laser beam wandering in isotropic turbulence

We have experimentally quantified the temporal structural diversity from the coordinate fluctuations of a laser beam propagating through isotropic optical turbulence. The main focus here is on the characterization of the long-range correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. To fulfill this goal, a laboratory-controlled experiment was conducted in which coordinate fluctuations of the laser beam were recorded at a sufficiently high sampling rate for a wide range of turbulent conditions. Horizontal and vertical displacements of the laser beam centroid were subsequently analyzed by implementing the symbolic technique based on ordinal patterns to estimate the well-known permutation entropy. We show that the permutation entropy estimations at multiple time scales evidence an interplay between different dynamical behaviors. More specifically, a crossover between two different scaling regimes is observed. We confirm a transition from an integrated stochastic process contaminated with electronic noise to a fractional Brownian motion with a Hurst exponent H = 5/6 as the sampling time increases. Besides, we are able to quantify, from the estimated entropy, the amount of electronic noise as a function of the turbulence strength. We have also demonstrated that these experimental observations are in very good agreement with numerical simulations of noisy fractional Brownian motions with a well-defined crossover between two different scaling regimes.Comment: 8 pages, 6 figure

Beam wandering statistics of twin thin laser beam propagation under generalized atmospheric conditions

Under the Geometrics Optics approximation is possible to estimate the covariance between the displacements of two thin beams after they have propagated through a turbulent medium. Previous works have concentrated in long propagation distances to provide models for the wandering statistics. These models are useful when the separation between beams is smaller than the propagation path—regardless of the characteristics scales of the turbulence. In this work we give a complete model for these covariances, behavior introducing absolute limits to the validity of former approximations. Moreover, these generalizations are established for non-Kolmogorov atmospheric models.Fil: Pérez, Darío Gabriel. Pontificia Universidad Católica de Valparaíso; ChileFil: Funes, Gustavo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Ópticas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones Ópticas. Universidad Nacional de La Plata. Centro de Investigaciones Ópticas; Argentin