Underlying SUSY in a generalized Jaynes–Cummings model

We present a general qubit-boson interaction Hamiltonian that describes the Jaynes–Cummings model and its extensions as a single Hamiltonian class. Our model includes non-linear processes for both the free qubit and boson field as well as non-linear, multi-boson excitation exchange between them. It shows an underlying algebra with supersymmetric quantum mechanics features allowing an operator based diagonalization that simplifies the calculations of observables. As a practical example, we show the evolution of the population inversion and the boson quadratures for an initial state consisting of the qubit in the ground state interacting with a coherent field for a selection of cases covering the standard Jaynes–Cummings model and some of its extensions including Stark shift, Kerr-like, intensity dependent coupling, multi-boson exchange and algebraic deformations

Short- and mid-term evaluation of the use of electric vehicles in urban freight transport collaborative networks: a case study

Despite its negative impacts, freight transportation is a primary component of all supply chains. Decision makers have considered diverse strategies, such as Horizontal Collaboration (HC) and the usage of alternative types of vehicles, to reduce overall cost and the related environmental and social impacts. This paper assesses the implementation of an electric fleet of vehicles in urban goods distribution under HC strategy between carriers. A biased randomisation based algorithm is used to solve the problem with a multi-objective function to explore the relationships between both delivery and environmental costs. Real data from the city of Bogota, Colombia are used to validate this approach. Experiments with different costs and demands projections are performed to analyse short- and medium-term impacts related to the usage of electric vehicles in collaborative networks. Results show that the optimal selection of vehicle types depends considerably on the time horizon evaluation and demand variation.This work has been partially supported by the Spanish Ministry of Economy and Competitiveness (TRA2013-48180-C3-P and TRA2015-71883-REDT) and the Ibero-American Program for Science and Technology for Development (CYTED2014-515RT0489). Likewise, we want to acknowledge the support received by the Special Patrimonial Fund from Universidad de La Sabana (Colombia) and the doctoral grant from the UOC-Open University of Catalonia (Spain)

GENESIS Y ELEMENTOS FUNDAMENTALES EN LA INNOVACIÓN EDUCATIVA DE TRES INSTITUCIONES DE BUCARAMANGA Y FLORIDABLANCA

RESUMEN Este artículo describe tres experiencias pedagógicas que hacen parte de la investigación sobre innovaciones educativas realizado en tres instituciones educativas de Bucaramanga y Floridablanca. Inicialmente se revisan los conceptos sobre Innovación y a continuación se presenta para cada una de las innovaciones la perspectiva teórica que las sustenta, luego se analizan, muy brevemente, los cambios realizados en las prácticas pedagógicas de cada una de las instituciones y los logros alcanzados en los procesos de enseñanza y aprendizaje por parte de los miembros de la comunidad educativa.   Palabras claves: Innovación, Pedagogía conceptual, Modificabilidad cognitiva, estrategias pedagógicas, evaluación   SUMMARY This article describes three pedagogical experiences which make part of the research on educational innovations carried out in three educational institutions in Bucaramanga and Floridablanca. First of all the concepts about innovations are rewied, and next each one of the innovations is presented based on the theoretical prospective which supported them. After that, the changes carried out in the pedagogical practices of each one of the institutions are briefly analized, as well as the achievements reach in the processes of teaching and learning on the part of the members of the educative community.   Key words: Innovation, conceptual pedagogy, cognitive variation, pedagogical strategies, evaluation

A low-absorption disk zone at low Galactic latitude in Centaurus

We investigate the properties of two stellar concentrations in a low-absorption disk zone in Centaurus, located respectively at $\ell=306.47^{\circ}$, $b=-0.61 ^{\circ}$, and $\ell=307.01^{\circ}$, $b=-0.74 ^{\circ}$. The present analysis is based mostly on 2MASS photometry, as well as optical photometry. Based on colour-magnitude diagrams and stellar radial density profiles, we show that these concentrations are not open star clusters. Instead, they appear to be field stars seen through a differentially-reddened window. We estimate that the bulk of the stars in both stellar concentrations is located at $\sim1.5$ kpc from the Sun, a distance consistent with that of the Sgr-Car arm in that direction. This low-absorption window allows one to probe into distant parts of the disk besides the Sgr-Car arm, probably the tangent part of the Sct-Cru arm, and/or the far side of the Sgr-Car arm in that direction. The main sequence associated to the Sgr-Car arm is reddened by \ebv\sim0.5, so that this window through the disk is comparable in reddening to Baade's window to the bulge. We also investigate the nature of the open cluster candidate Ru 166. The presently available data do not allow us to conclude whether Ru 166 is an actual open cluster or field stars seen through a small-scale low-absorption window

Updated Big Bang Nucleosynthesis Bounds on Long-lived Particles from Dark Sectors

As electromagnetic showers may alter the abundance of Helium, Lithium, and Deuterium, we can place severe constraints on the lifetime and amount of electromagnetic energy injected by long-lived particles. Considering up-to-date measurements of the light element abundances that point to $Y_p=0.245\pm 0.003$,$({\rm D/H})= (2.527\pm 0.03)\times 10^{-5}$,$(^7{\rm Li/H})=1.58 ^{+0.35}_{-0.28} \times 10^{-10}$, $(^6{\rm Li/^7 Li})=0.05$, and the baryon-to-photon ratio obtained from the Cosmic Microwave Background data, $\eta=6.104 \times 10^{-10}$, we derive upper limits on the fraction of electromagnetic energy produced by long-lived particles. Our findings apply to decaying dark matter models, long-lived gravitinos, and other non-thermal processes that occurred in the early universe between $10^2-10^{10}$ seconds.Comment: 7 pages, 3 figure

Conocimiento didáctico del contenido curricular en la enseñanza de la combustión

Esta comunicación presenta resultados parciales de la investigación Conocimiento didáctico del contenido curricular en la enseñanza de la combustión, realizada en el año 2008 en la UPN en Bogotá, donde se caracterizó el conocimiento didáctico del contenido curricular en química (CDCC) de los profesores en formación inicial (PFI) y en ejercicio (PE) en relación con la enseñanza del concepto Combustión; se hizo un análisis documental de lo diseñado para la enseñanza y se determinaron si sus concepciones eran propias de la teoría del flogisto o de la teoría del oxígeno; se diseñó una trama histórica/epistemológica (THE) de estas teorías y una trama didáctica (TD) para construir una unidad didáctica. Esta investigación es parte de un proyecto financiado por el Centro de investigaciones de la UPN, DQU-025-07