Hamiltonian Dynamics and the Phase Transition of the XY Model

A Hamiltonian dynamics is defined for the XY model by adding a kinetic energy term. Thermodynamical properties (total energy, magnetization, vorticity) derived from microcanonical simulations of this model are found to be in agreement with canonical Monte-Carlo results in the explored temperature region. The behavior of the magnetization and the energy as functions of the temperature are thoroughly investigated, taking into account finite size effects. By representing the spin field as a superposition of random phased waves, we derive a nonlinear dispersion relation whose solutions allow the computation of thermodynamical quantities, which agree quantitatively with those obtained in numerical experiments, up to temperatures close to the transition. At low temperatures the propagation of phonons is the dominant phenomenon, while above the phase transition the system splits into ordered domains separated by interfaces populated by topological defects. In the high temperature phase, spins rotate, and an analogy with an Ising-like system can be established, leading to a theoretical prediction of the critical temperature $T_{KT}\approx 0.855$.Comment: 10 figures, Revte

Semiclassical coherent state propagator for systems with spin

We derive the semiclassical limit of the coherent state propagator for systems with two degrees of freedom of which one degree of freedom is canonical and the other a spin. Systems in this category include those involving spin-orbit interactions and the Jaynes-Cummings model in which a single electromagnetic mode interacts with many independent two-level atoms. We construct a path integral representation for the propagator of such systems and derive its semiclassical limit. As special cases we consider separable systems, the limit of very large spins and the case of spin 1/2.Comment: 19 pages, no figure

A Business Intelligence Framework for Analyzing Educational Data

Currently, universities are being forced to change the paradigms of education, where knowledge is mainly based on the experience of the teacher. This change includes the development of quality education focused on students’ learning. These factors have forced universities to look for a solution that allows them to extract data from different information systems and convert them into the knowledge necessary to make decisions that improve learning outcomes. The information systems administered by the universities store a large volume of data on the socioeconomic and academic variables of the students. In the university field, these data are generally not used to generate knowledge about their students, unlike in the business field, where the data are intensively analyzed in business intelligence to gain a competitive advantage. These success stories in the business field can be replicated by universities through an analysis of educational data. This document presents a method that combines models and techniques of data mining within an architecture of business intelligence to make decisions about variables that can influence the development of learning. In order to test the proposed method, a case study is presented, in which students are identified and classified according to the data they generate in the different information systems of a university

Analysis of Educational Data in the Current State of University Learning for the Transition to a Hybrid Education Model

Currently, the 2019 Coronavirus Disease pandemic has caused serious damage to health throughout the world. Its contagious capacity has forced the governments of the world to decree isolation and quarantine to try to control the pandemic. The consequences that it leaves in all sectors of society have been disastrous. However, technological advances have allowed people to continue their different activities to some extent while maintaining isolation. Universities have great penetration in the use of technology, but they have also been severely affected. To give continuity to education, universities have been forced to move to an educational model based on synchronous encounters, but they have maintained the methodology of a face-to-face educational model, what has caused several problems in the learning of students. This work proposes the transition to a hybrid educational model, provided that this transition is supported by data analysis to identify the new needs of students. The knowledge obtained is contrasted with the performance presented by the students in the face-to-face modality and the necessary parameters for the transition to this modality are clearly established. In addition, the guidelines and methodology of online education are considered in order to take advantage of the best of both modalities and guarantee learning

Proceso agrario en Bolivia y América Latina

El material esta distribuido en cinco partes. La primera está referida a los resultados y perspectivas de la Reforma Agraria en Bolivia. Está dividida en tres temáticas: la Reforma Agraria en las Tierras Altas, la Reforma Agraria en las Tierras Bajas y la Reforma Agraria en el Chaco. La segunda parte contiene las intervenciones realizadas por los invitados extranjeros sobre los resultados y perspectivas de la Reforma Agraria en América Latina y en México, Perú y Ecuador. La tercera parte corresponde a las intervenciones de los representantes de las organizaciones indígenas y campesinas bolivianas, que fueron invitados para debatir el tema Tierra, Democracia y Poder. Esta parte esta precedida por un recuento general de la situación de los Movimientos Indígenas-Campesinos en América Latina y sus perspectivas. La cuarta da cuenta de las intervenciones hechas por los representantes de las organizaciones de productores agrarios, campesinos y empresarios, quienes fueron invitados para debatir el tema Tierra, Economía e Integración. La última parte es una síntesis de las ideas y aspectos relevantes producto de las exposiciones y de las preguntas de los asistentes al seminario, que dejaron una estela de inquietudes e iniciativas que son el eslabón para futuros debates en otros espacios de reflexión en diferentes lugares del país, con la participación de actores y pensadores, operadores y promotores del desarrollo rural.Presentación 7; Introducción 8; La Reforma Agraria abandonada: valles y altiplano, Miguel Urioste F. de C. 19; Medio siglo de Reforma Agraria boliviana, Danilo Paz Ballivián 53; La tierra es de quien la trabaja, René Salomón Vargas 65; La Reforma Agraria en las tierras bajas de Bolivia, Carlos Romero Bonifaz 83; Lógicas de ocupación territorial en la agricultura y la forestería empresarial en las tierras bajas, Alan Bojanic 127; Antecedentes, situación actual y recomendaciones en la tenencia de la tierra en el oriente boliviano, Cámara Agropecuaria del Oriente 137; 50 años de la Reforma Agraria en el Chaco boliviano, Oscar Bazoberry Chali 145; Resultados de los cambios introducidos por la Reforma Agraria, Erwin Galoppo von Borries 177; La Reforma Agraria en Bolivia y el MST, Ermelinda Fernández Bamba 191; La Reforma Agraria en América Latina, Jacques Chonchol 205; De rústicas revueltas: Añoranza y utopía en el México rural, Armando Bartra 223; Reforma y contrarreforma agraria en el Perú, Laureano del Castillo Pinto 255; Reforma Agraria en el Ecuador, Fausto Jordán B. 285; 50 años después, emergencia étnica, Xavier Albó 321; Tierra, mujer y desarrollo, María Machaca 329; Tierra y territorio comunitario, Bienvenido Zacu 333; Tierra, migración y colonización, José Luis Méndez Chaurara 341; Tierra, coca y desarrollo, Dionisio Núñez 355; Tierra para todos, Ángel Durán 359; Tierra y producción orgánica, Mario R. Cordero Camacho 367; Tierra y producción campesina, María Julia Jiménez 377; Tierra y Territorio y Políticas para la Tierra, Elizabeth Jiménez Zamora 385; Ideas y aspectos relevantes del Seminario, John D.Vargas Vega 429

The treatment of Internet Gaming Disorder: a brief overview of the PIPATIC program

Over the last decade, there has been an increase in children and adolescents accessing psychology services regarding problematic use of online videogames. Consequently, providing effective treatment is essential. The present paper describes the design process of a manualized PIPATIC (Programa Individualizado Psicoterapéutico para la Adicción a las Tecnologías de la información y la comunicación) intervention program for 12- to 18-year-old adolescents with Internet Gaming Disorder. The design and application of the PIPATIC program integrates several areas of intervention structured into six modules: psychoeducational, treatment as usual, intrapersonal, interpersonal, family intervention, and development of a new lifestyle. The program’s goals are to reduce the addiction symptoms related to online videogames and to improve the well-being of adolescents. Preliminary findings suggest positive and encouraging effects

Do lambs perceive regular human stroking as pleasant? Behavior and heart rate variability analyses

Stroking by humans is beneficial to the human-animal relationship and improves welfare in many species that express intraspecific allogrooming, but very few studies have looked at species like sheep that do not express such contact except around parturition. This study investigated the way lambs perceive regular human tactile contact using behavioral and physiological responses. Twenty-four lambs were reared and bucket-fed in groups of four. All were stroked daily by their familiar caregiver. At 8 weeks of age, the lambs were individually tested in their home pen but in a 1×1m open-barred pen after a 15h period of habituation to physical separation from peers while remaining in visual and auditory contact. Half of the lambs received stroking by their caregiver for 8min and half were exposed to their caregiver’s immobile presence. Heart rate and heart rate variability were recorded and analyzed by 2-min slots over the same interval based on three measures: mean heart rate value (HR), root mean square of successive differences (RMSSD) and standard deviation of all intervals measured between consecutive sinus beats (SDNN). Behavioral responses (ear postures of the lamb and time spent in contact with the familiar caregiver, on the knees of the familiar caregiver, and moving) were recorded throughout the test. Lamb HR decreased continuously while in the presence of their caregiver. Lambs being stroked showed slower HR and higher RMSSD which reflected positive emotional states compared to lambs left unstroked. All behavioral variables were highly correlated with the main component axis of the PCA analyses: the more the animals stayed in contact with their caregiver, the less they moved and the more their ears were hanging. This first component clearly differentiates lambs being stroked or not. Behavioral and physiological observations support the hypothesis that gentle physical contact with the caregiver is perceived positively by lambs

The 12p13.33/RAD52 locus and genetic susceptibility to squamous cell cancers of upper aerodigestive tract

Acknowledgments: The authors thank all of the participants who took part in this research and the funders and support and technical staff who made this study possible. We also acknowledge and thank The Cancer Genome Atlas initiative whose data contributed heavily to this study. Funding: Funding for study coordination, genotyping of replication studies and statistical analysis was provided by the US National Institutes of Health (R01 CA092039 05/05S1) and the National Institute of Dental and Craniofacial Research (1R03DE020116). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

The problematic use of Information and Communication Technologies (ICT) in adolescents by the cross sectional JOITIC study

Background: The emerging field of Information and Communications Technology (ICT) has brought about new interaction styles. Its excessive use may lead to addictive behaviours. The objective is to determine the prevalence of the problematic use of ICT such as Internet, mobile phones and video games, among adolescents enrolled in mandatory Secondary Education (ESO in Spanish) and to examine associated factors. Methods: Cross sectional, multi-centric descriptive study. Population: 5538 students enrolled in years one to four of ESO at 28 schools in the Vallès Occidental region (Barcelona, Spain). Data collection: self-administered socio-demographic and ICT access questionnaire, and validated questionnaires on experiences related to the use of the Internet, mobile phones and video games (CERI, CERM, CERV). Results: Questionnaires were collected from 5,538 adolescents between the ages of 12 and 20 (77.3 % of the total response), 48.6 % were females. Problematic use of the Internet was observed in 13.6 % of the surveyed individuals; problematic use of mobile phones in 2.4 % and problematic use in video games in 6.2 %. Problematic Internet use was associated with female students, tobacco consumption, a background of binge drinking, the use of cannabis or other drugs, poor academic performance, poor family relationships and an intensive use of the computer. Factors associated with the problematic use of mobile phones were the consumption of other drugs and an intensive use of these devices. Frequent problems with video game use have been associated with male students, the consumption of other drugs, poor academic performance, poor family relationships and an intensive use of these games. Conclusions: This study offers information on the prevalence of addictive behaviours of the Internet, mobile phones and video game use. The problematic use of these ICT devices has been related to the consumption of drugs, poor academic performance and poor family relationships. This intensive use may constitute a risk marker for ICT addictio