Dynamics of quantum correlations and linear entropy in a multi-qubit-cavity system

We present a theoretical study of the relationship between entanglement and entropy in multi-qubit quantum optical systems. Specifically we investigate quantitative relations between the concurrence and linear entropy for a two-qubit mixed system, implemented as two two-level atoms interacting with a single-mode cavity field. The dynamical evolutions of the entanglement and entropy, are controlled via time-dependent cavity-atom couplings. Our theoretical findings lead us to propose an alternative measure of entanglement, which could be used to develop a much needed correlation measure for more general multi-partite quantum systems.Comment: New discussions on the generality of entanglement-entropy relationship, one new reference, and other minor changes. 10 pages, 6 figures, accepted for publication in J.Opt. B: "Special Issue on Fluctuations & Noise in Photonics & Quantum Optics.

Effectiveness of a new approach for exclusive breastfeeding counselling on breastfeeding prevalence, infant growth velocity and postpartum weight loss in overweight or obese women: protocol for a randomized controlled trial

Background: Maternal overweight, infant feeding and early growth velocity are risk factors for obesity later in life. The first one thousand days are a window of opportunity to program health and disease. Exclusive breastfeeding may protect against obesity; however, it is not consistently practiced. Obesity rates have been increasing worldwide. Overweight or obese women have lower rates of breastfeeding and face mechanical, psychological and biological difficulties. Breastfeeding counselling is a successful strategy to support breastfeeding in normal weight women; but there is a lack of evidence on its effectiveness in overweight women. Our purpose is to evaluate a new approach to exclusive breastfeeding counselling based on Carl Rogers' Centred-Client Theory in overweight women, and to examine effects on breastfeeding prevalence, infant growth velocity and maternal postpartum weight loss. Methods: A two-arm simple randomized controlled trial will be conducted in overweight and obese women recruited in a Baby Friendly Hospital in Bogotá, Colombia. The intervention is exclusive breastfeeding counselling based on Rogers' theory but adapted for overweight women; it will be performed during the last month of pregnancy, 24 h after delivery and during early infancy (1 and 3 months postpartum). The primary outcomes will be exclusive breastfeeding prevalence, infant growth velocity and maternal weight loss from birth up to 4 months after delivery; and the secondary outcomes will be prolactin and macronutrient levels in breast milk and serum prolactin levels. Intention to treat analysis will be performed to estimate the effect of the new counselling approach compared to standard management on the prevalence of exclusive breastfeeding, infant growth velocity and maternal weight loss. Discussion: We hypothesize that the intervention will result in an increase in the initiation and maintenance of exclusive breastfeeding, allowing adequate infant growth velocity and maternal weight loss after delivery. It is hoped that the results of this trial will provide evidence to support public health policy on supporting breastfeeding in this vulnerable group of women. Trial registration: (UTN) U1111-1228-9913 February 20th 2019; ISRCTN15922904February 27th 2019, retrospectively registered

Quantitative aspects of entanglement in the optically driven quantum dots

We present a novel approach to look for the existence of maximum entanglement in a system of two identical quantum dots coupled by the Forster process and interacting with a classical laser field. Our approach is not only able to explain the existing treatments, but also provides further detailed insights into the coupled dynamics of quantum dots systems. The result demonstrates that there are two ways for generating maximum entangled states, one associated with far off-resonance interaction, and the other associated with the weak field limit. Moreover, it is shown that exciton decoherence results in the decay of entanglement.Comment: 13 pages, 4 figure

Efficiency of energy transfer in a light-harvesting system under quantum coherence

We investigate the role of quantum coherence in the efficiency of excitation transfer in a ring-hub arrangement of interacting two-level systems, mimicking a light-harvesting antenna connected to a reaction center as it is found in natural photosynthetic systems. By using a quantum jump approach, we demonstrate that in the presence of quantum coherent energy transfer and energetic disorder, the efficiency of excitation transfer from the antenna to the reaction center depends intimately on the quantum superposition properties of the initial state. In particular, we find that efficiency is sensitive to symmetric and asymmetric superposition of states in the basis of localized excitations, indicating that initial state properties can be used as a efficiency control parameter at low temperatures.Comment: Extended version of original paper. 7 pages, 2 figure

La bicicleta como transporte sostenible en México

De acuerdo a los datos publicados por el Banco Mundial (actualización 31 de octubre del 2012), México presentó una tendencia hacia la baja a pesar de esto, aún sigue siendo considerable sus emisiones de CO2 actualmente es de 3.98 ton per cápita. Esto contribuye al efecto invernadero y a su vez desequilibrios en nuestros ecosistemas. Siendo así uno de los eventos que aportan efectos al cambio climático. A partir de este planteamiento se busca llevar a cabo propuestas viables y que motiven a la creación de un sistema que sea respetuoso con el medio ambiente con un desarrollo económico local y eficientizar la infraestructura existente además de mejorar la imagen urbana así como promover la salud a través del uso de la bicicleta, así mismo tener una ciudad más competitiva con reducciones de emisiones de carbono que abone a la reducción del cambio climático. Para contribuir en su mitigación, se impulsa la realización del Plan de Movilidad Ciclista de Ensenada, con el fin de mejorar la calidad de vida de la población y mejorar las condiciones actuales de los problemas medioambientales al participar en la reducción de CO2 y promover el uso de la bicicleta como medio de transporte no motorizado. El proyecto, en su primera fase, consiste en retirar 166 aparcamientos dispuestos a lo largo del Boulevard Costero de la zona turística en aparcamientos públicos, y así usar este espacio para desarrollar una ruta de la ciclovía. Comprobamos que uno de los medios de transporte más vendidos en México (no así en el 2012) es el Nissan Tsuru 2008, por ser un auto económico y de bajo mantenimiento. Analizamos la emisión del CO2, considerándolo como un vehículo de rango medio en la eficiencia de emisión de gases contaminantes, y si consideramos que el 34.14% (como valor representativo) de los autos que ya no estarían estacionados en esa vialidad se sustituyen por uso de bicicleta, obtenemos que la reducción de emisiones de CO2 durante un año al implementar la primera fase del Plan de Movilidad Ciclista, es de 71,76 tonelada

Association between traumatic events and post-traumatic stress disorder: results from the ESEMeD-Spain study

Background: The relative importance of traumatic events (TEs) in accounting for the social burden of post-traumatic stress disorder (PTSD) could vary according to cross-cultural factors. In that sense, no such studies have yet been conducted in the Spanish general population. The present study aims to determine the epidemiology of trauma and PTSD in a Spanish community sample using the randomly selected TEs method. Methods: The European Study of the Epidemiology of Mental Disorders (ESEMeD)-Spain is a cross-sectional household survey of a representative sample of adult population. Lifetime prevalence of self-reported TEs and lifetime and 12-month prevalence of PTSD were evaluated using the World Health Organization (WHO) Composite International Diagnostic Interview. Reports of PTSD associated with randomly selected TEs were weighted by the individual-level probabilities of TE selection to generate estimates of population-level PTSD risk associated with each TE. Results: Road accident was the most commonly self-reported TE (14.1%). Sexual assault had the highest conditional risk of PTSD (16.5%). The TEs that contributed most to societal PTSD burden were unexpected death of a loved one (36.4% of all cases) and sexual assault (17.2%). Being female and having a low educational level were associated with low risk of overall TE exposure and being previously married was related to higher risk. Being female was related to high risk of PTSD after experiencing a TE. Conclusions: Having an accident is commonly reported among Spanish adults, but two TE are responsible for the highest burden associated with PTSD: the unexpected death of someone close and sexual assault. These results can help designing public health interventions to reduce the societal PTSD burden

Optical signatures of quantum phase transitions in a light-matter system

Information about quantum phase transitions in conventional condensed matter systems, must be sought by probing the matter system itself. By contrast, we show that mixed matter-light systems offer a distinct advantage in that the photon field carries clear signatures of the associated quantum critical phenomena. Having derived an accurate, size-consistent Hamiltonian for the photonic field in the well-known Dicke model, we predict striking behavior of the optical squeezing and photon statistics near the phase transition. The corresponding dynamics resemble those of a degenerate parametric amplifier. Our findings boost the motivation for exploring exotic quantum phase transition phenomena in atom-cavity, nanostructure-cavity, and nanostructure-photonic-band-gap systems.Comment: 4 pages, 4 figure

Flipped Learning to improve students' motivation in Physical Education

Background: Active methodologies have emerged in which they focus their importance of the teaching-learning process in students and not only on the result. In this way, research has been conducted using the active methodology Flipped Learning (FL) in all areas of Primary, Secondary and Higher Education. Objective: The current study aims to analyze the effect on student motivation after an intervention with the FL teaching technique, using a Parkour Didactic Unit in primary school students. Methods: One hundred students of 6th grade of Primary (11-12 years old) participated in this study, of which, 45 were girls and 55 were boys. It was randomly decided that 6ºB and 6ºD would follow the teaching styles that were already used in the center regularly (TRAD group) and otherwise, the 6ºA and 6ºC groups used FL teaching technique by watching videos created by the principal investigator for the present investigation (FLIP group). The Motivation Questionnaire in Physical Education in primary education and personal interview were applied before and after intervention. Results: The results showed an increase of intrinsic motivation (p < .001), identified motivation (p < .001) and introjected motivation (p < .001) in FLIP group. Moreover, external motivation, as well as the amotivation of the students, has decreased after the intervention. Regarding the TRAD group, a significant decrease in intrinsic motivation and identified motivation was observed. According to qualitative results, the most remarkable thing is that students consider FL as more fun, efficient, accepted and motivating. Conclusions: Intrinsic motivation increased significantly and amotivation values decrease in FL group. FL approach allows using more time in Physical Education classes and, consequently, it is perceived as more fun for the students

Evolución de las funciones ejecutivas de adictos a la cocaína tras un año de tratamiento

Introducción: Numerosos estudios han confirmado la presencia de alteraciones en las funciones ejecutivas de adictos a la cocaína, pero pocos han investigado el curso temporal y patrón evolutivo de estos déficits. Los objetivos del presente estudio consistieron en (1) evaluar el perfil neuropsicológico de consumidores de cocaína que han completado un año de tratamiento, (2) describir la evolución de los déficits a lo largo del tratamiento y discutir qué variables pueden mediar su recuperación. Material y Método: 50 pacientes en tratamiento por adicción a la cocaína fueron reclutados aleatoriamente en el programa ambulatorio de Proyecto Hombre Asturias. Durante la admisión al programa y tras completar doce meses de tratamiento se aplicó un protocolo de evaluación neuropsicológica sensible a la detección de alteraciones en diferentes componentes de las funciones ejecutivas. Resultados: en general se encontró una tendencia hacia la mejoría en las puntuaciones en la batería neuropsicológica tras doce meses de tratamiento, aunque no en todas las tareas. El rendimiento neuropsicológico en pruebas relacionadas con atención y fluidez mejoró, se mantuvo estable en tareas relacionadas con control inhibitorio y empeoró en tareas de flexibilidad mental. Discusión: se produjo una mejoría global del rendimiento neuropsicológico, por lo que se puede pensar en la posibilidad de reversibilidad de las alteraciones en las funciones ejecutivas en pacientes adictos a la cocaína

Non-Markovian stochastic description of quantum transport in photosynthetic systems

We analyze several aspects of the transport dynamics in the LH1-RC core of purple bacteria, which consists basically in a ring of antenna molecules that transport the energy into a target molecule, the reaction center, placed in the center of the ring. We show that the periodicity of the system plays an important role to explain the relevance of the initial state in the transport efficiency. This picture is modified, and the transport enhanced for any initial state, when considering that molecules have different energies, and when including their interaction with the environment. We study this last situation by using stochastic Schr{\"o}dinger equations, both for Markovian and non-Markovian type of interactions.Comment: 21 pages, 5 figure