Nongauge bright soliton of the nonlinear Schrodinger (NLS) equation and a family of generalized NLS equations

We present an approach to the bright soliton solution of the NLS equation from the standpoint of introducing a constant potential term in the equation. We discuss a `nongauge' bright soliton for which both the envelope and the phase depend only on the traveling variable. We also construct a family of generalized NLS equations with solitonic sech^p solutions in the traveling variable and find an exact equivalence with other nonlinear equations, such as the Korteveg-de Vries and Benjamin-Bona-Mahony equations when p=2Comment: ~4 pages, 3 figures, 16 references, published versio

Nongauge Bright Soliton of the Nonlinear Schrodinger (NLS) Equation and a Family of Generalized NLS Equations

We present an approach to the bright soliton solution of the nonlinear Schrödinger (NLS) equation from the standpoint of introducing a constant potential term in the equation. We discuss a “nongauge” bright soliton for which both the envelope and the phase depend only on the traveling variable. We also construct a family of generalized NLS equations with solitonic sechpsechp solutions in the traveling variable and find an exact equivalence with other nonlinear equations, such as the Korteveg–de Vries (KdV) and Benjamin–Bona–Mahony (BBM) equations when p=2

Characterization and distribution of sedimentary facies of Cartagena Bay, Colombia.

En el análisis sedimentológico de 253 muestras de sedimentos de fondo y borde de playa de la Bahía de Cartagena, se identificaron 26 facies sedimentarias. Las muestras fueron tomadas con draga tipo Van Veen para el fondo, multimuestreador de sedimento tipo Beeker y apiques para los bordes de playa. Las muestras fueron tamizadas y se obtuvieron 15 categorías de acuerdo al tamaño de grano, posteriormente se realizó el análisis de carbonato de calcio (CaCO3) usando el calcímetro de Bernard. Los sedimentos fueron clasificados de acuerdo con el tamaño medio de grano y el contenido de CaCO3, para definir las facies sedimentarias existentes, donde la facies lodo litoclástico es la más representativa y se distribuye en la bahía interna y externa; al norte y sur de la Isla de Tierra Bomba. Se encontró que durante los últimos 30 años la distribución de las facies sedimentarias ha experimentado variaciones significativas: en la bahía interna ha disminuido el contenido de CaCO3 y al suroeste ha disminuido el tamaño de grano y el contenido de CaCO3; como resultado del creciente aporte de sedimentos del Canal de Dique y las condiciones oceanográficas presentes. Estas condiciones hidrodinámicas favorecen la meteorización y erosión de las formaciones coralinas presentes en el Caribe Colombiano.In the sedimentological analysis of 253 sediment samples from the edges and the bottom of the Cartagena bay, we identified 26 sedimentary facies. Samples were taken with Van Veen dredge for the bottom sediment Beeker multisampler and test pits for shorelines. Using the Bernard calcimeter we carried out the calcium carbonate (CaCO3) analysis in every sieved sample. Sediments were classified according to the average grain size and content of CaCO3, to define the existing sedimentary facies, where mud litoclast facies was the most representative and distributed to the north and south of the Tierra Bomba in the internal and external bay. We found that during the past 30 years the distribution of sedimentary facies has experienced significant changes: in the inner bay the content of CaCO3 has decreased and in the southwest the grain size and content of CaCO3 have decreased, as a result of the sediments contribution from Canal del Dique and present oceanographic conditions. These hydrodynamic conditions contribute to the weathering and erosion of coral formations present in the Colombian CaribbeanFil: Franco Arias, Diana Aillen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Geológico del Sur; Argentina. Universidad Industrial de Santander; ColombiaFil: Restrepo López, J. C.. Universidad del Norte; ColombiaFil: Sanabria Ruiz, N. Y.. Universidad Industrial de Santander; ColombiaFil: Gutierrez, Julio C.. Centro de Investigaciones Oceanográficas e Hidrográficas; Colombi

Detection and Analysis of ERPs for Social Cognition Evaluation

This paper describes an approach for elicitation, acquisition, and analysis of event-related potentials (ERPs) for social cognition evaluation. We used images of emotional content that were classified into three groups according to their valence: pleasant, unpleasant, and neutral. An application for stimuli generation based on the emotional oddball paradigm (EOP) was developed, and a commercial wireless EEG headset was used for signal acquisition. The ERPs of 13 volunteers for the three types of stimuli were obtained and analyzed to extract the N100 and P300 components. The results show increased amplitudes in ERP components due to unpleasant stimuli and longer latencies observed in neutral stimuli. © 2022 IEEE

Discovering dynamic laws from observations: the case of self-propelled, interacting colloids

Active matter spans a wide range of time and length scales, from groups of cells and synthetic self-propelled particles to schools of fish, flocks of birds, or even human crowds. The theoretical framework describing these systems has shown tremendous success at finding universal phenomenology. However, further progress is often burdened by the difficulty of determining the forces that control the dynamics of the individual elements within each system. Accessing this local information is key to understanding the physics dominating the system and to create the models that can explain the observed collective phenomena. In this work, we present a machine-learning model, a graph neural network, that uses the collective movement of the system to learn the active and two-body forces controlling the individual dynamics of the particles. We verify our approach using numerical simulations of active brownian particles, considering different interaction potentials and levels of activity. Finally, we apply our model to experiments of electrophoretic Janus particles, extracting the active and two-body forces that control the dynamics of the colloids. Due to this, we can uncover the physics dominating the behavior of the system. We extract an active force that depends on the electric field and also area fraction. We also discover a dependence of the two-body interaction with the electric field that leads us to propose that the dominant force between these colloids is a screened electrostatic interaction with a constant length scale. We expect that this methodology can open a new avenue for the study and modeling of experimental systems of active particles

Fluorescent and Electroactive Monoalkyl BTD-Based Liquid Crystals with Tunable Self-Assembling and Electronic Properties

We report here on a series of redox active benzothiadiazole-based luminophores ffinctionalized on one edge with a phenyl-nonyl substituent, which confers these molecules a rodlike shape and a tendency to self-assemble into layered superstructures. On the other edge, the molecules are endowed with different p-substituted phenyl rings, which allows the modulation of their redox and optical properties on the basis of the electronic nature of the terminal substituents. We have found that just one lateral alkyl chain is sufficient to induce mesomorphism in these molecules, which present nematic or smectic mesophases upon therinal treatment. Single-crystal analysis allows us to get an insight into the nature of the forces responsible for different supramolecular assemblies in these derivatives, and point to a strong contribution of the terminal groups in the different arrangements observed. The interesting redox and optical properties together with their self-assembling tendencies render these new materials interesting candidates for optoelectromcs