Double excitations and state-to-state transition dipoles in pi-pi* excited singlet states of linear polyenes: Time-dependent density-functional theory versus multiconfigurational methods

The effect of static and dynamic electron correlation on the nature of excited states and state-to-state transition dipole moments is studied with a multideterminant wave function approach on the example of all-trans linear polyenes (C4H6, C6H8, and C8H10). Symmetry-forbidden singlet nA(g) states were found to separate into three groups: purely single, mostly single, and mostly double excitations. The excited-state absorption spectrum is dominated by two bright transitions: 1B(u)-2A(g) and 1B(u)-mA(g), where mA(g) is the state, corresponding to two-electron excitation from the highest occupied to lowest unoccupied molecular orbital. The richness of the excited-state absorption spectra and strong mixing of the doubly excited determinants into lower-nA(g) states, reported previously at the complete active space self-consistent field level of theory, were found to be an artifact of the smaller active space, limited to pi orbitals. When dynamic sigma-pi correlation is taken into account, single- and double-excited states become relatively well separated at least at the equilibrium geometry of the ground state. This electronic structure is closely reproduced within time-dependent density-functional theory (TD DFT), where double excitations appear in a second-order coupled electronic oscillator formalism and do not mix with the single excitations obtained within the linear response. An extension of TD DFT is proposed, where the Tamm-Dancoff approximation (TDA) is invoked after the linear response equations are solved (a posteriori TDA). The numerical performance of this extension is validated against multideterminant-wave-function and quadratic-response TD DFT results. It is recommended for use with a sum-over-states approach to predict the nonlinear optical properties of conjugated molecules

All-optical delay technique for supporting multiple antennas in a hybrid optical - wireless transmission system

We introduce a novel continuously-variable optical delay technique to support beam-forming wireless communications systems using antenna arrays. We demonstrate delay with 64-QAM modulated signals at a rate of 15 Msymbol/sec with 2.5 GHz carrier frequency

Two Models of Coteaching from University Teaching Staff: Phenomenographic Research

The literature of coteaching in the post-secondary landscape encompasses a wide array of different conceptions. Having multiple meanings of coteaching in higher education may pose some challenges for effectively implementing and researching this collaborative model. We should have a clear picture of the qualitatively different ways in which educators who co-teach in post-secondary settings understand this practice. Aiming to offer one of the first contributions to this effort, we analyzed the experiences of 16 university coteaching practitioners from a top university in Bogotá, Colombia. The sample participants´ interviews were analyzed using a phenomenographic methodology (Marton, 1981), which seeks to capture the variation and complexity of the understanding of a phenomenon. Our findings reveal two perspectives for understanding coteaching, one relying on the meaning (referential conceptions) and the other on the practice (structural conceptions). Participants´ coteaching meanings are determined by four qualitatively different understandings: cooperative teaching, collaborative teaching, pedagogical training, and critical pedagogy. When it comes to practice, the findings show eight categories, some of which have been previously described in narrative accounts about coteaching. The variability emerging from our findings highlights conceptual multiplicity rather than uniformity, thereby shedding light on the complexity of coteaching in post-secondary settings

Conocimiento y poder: la asimetría de intereses de los médicos colombianos y de Rockefeller en la construcción del concepto de fiebre amarilla selvática, 1907-1938

Este estudio examina las asimetrías entre los diferentes intereses de los funcionarios y médicos que trabajaron para la Fundación Rockefeller y sus contrapartes colombianas en el desarrollo y consolidación del concepto de 'fiebre amarilla de la selva', a diferencia de la conocida forma urbana de fiebre amarilla. Exploramos las respuestas de investigación a una variedad de brotes de enfermedades en Colombia en el contexto de las campañas de Rockefeller contra la fiebre amarilla, desde la descripción inicial de Roberto Franco de la 'fiebre amarilla de los bosques' en 1907 hasta la consolidación del concepto. de 'fiebre amarilla de la jungla' de Fred Soper en 1938.This study examines the asymmetries among the different interests of officials and medical doctors who worked for the Rockefeller Foundation and their Colombian counterparts in the development and consolidation of the concept of “jungle yellow fever,” as distinguished from the known urban form ofyellow fever. We explore the research responses to a variety of disease outbreaks in Colombia in the context of the Rockefeller campaigns against yellow fever, from the time of Roberto Franco’s initial description of “yellow fever of the forests” in 1907 until the consolidation of the concept of “jungle yellow fever” by Fred Soper in 1938.Cette étude examine las divergencias de interes parmi les fonction-naires et les meddecins qui ont travaillé pour la Fondation Rockefeller et sa filiale colombienne dans le développement et la consolidation du concept de «la fièvre jaune selvatique», qui diffère de la forme connue de fièvre jaune urbaine. Nous explorons les réponses de recherche à une variété d'irruptions de maladie en Colombie dans le contextte des campagnes de la Fondation Rockefeller con-tre la fìèvre jaune depuis la description initle de la «fièvre jaune des forêts» de Roberto Franco en 1907 jusqu ' à la consolidación del concepto de fièvre jaune sel-vatique por Fred Soper en 1938

Live Migration Downtime Analysis of a VNF Guest for a Proposed Optical FMC Network Architecture

Fixed Mobile Convergence (FMC) implies use of a shared optical fronthaul network infrastructure able to carry transparently both fixed and mobile traffic including Wi-Fi, Mobile and fixed Ethernet. Network Function Virtualization (NFV) is a main enabler for FMC using a shared infrastructure for fixed and mobile gateways. Live migration, a virtualization key-feature, offers load-balancing, increased energy efficiency, application elasticity and other worthy advantages. This paper presents the evaluation of migrating a VNF over an FMC infrastructure. Our results show that, performing a livemigration over a dedicated connection yielded zero downtime and met a benchmark delay. The following scenario, where the ongoing connection is re-routed on a different optical path, shows the successful completion of the migration with an increase in delay of 2.4 seconds (22% higher than the benchmark) and only 2.1 seconds downtime Fixed Mobile Convergence (FMC) implies use of a shared optical fronthaul network infrastructure able to carry transparently both fixed and mobile traffic including Wi-Fi, Mobile and fixed Ethernet. Network Function Virtualization (NFV) is a main enabler for FMC using a shared infrastructure for fixed and mobile gateways. Live migration, a virtualization key-feature, offers load-balancing, increased energy efficiency, application elasticity and other worthy advantages. This paper presents the evaluation of migrating a VNF over an FMC infrastructure. Our results show that, performing a live migration over a dedicated connection yielded zero downtime and met a benchmark delay. The following scenario, where the ongoing connection is re-routed on a different optical path, shows the successful completion of the migration with an increase in delay of 2.4 seconds (22% higher than the benchmark) and only 2.1 seconds downtime