Driving quantized vortices with quantum vacuum fluctuations

We propose to use a rotating corrugated material plate in order to stir, through the Casimir-Polder interaction, quantized vortices in an harmonically trapped Bose-Einstein condensate. The emergence of such vortices within the condensate cannot be explained with a computation of the Casimir-Polder potential based on the pairwise summation approach or on the proximity force approximation. It thus appears as a genuine signature of non-trivial geometry effects on the electromagnetic vacuum fluctuations, which fully exploits the superfluid nature of the sample. In order to discuss quantitatively the generation of Casimir-driven vortices, we derive an exact non-perturbative theory of the Casimir-Polder potential felt by the atoms in front of the grating. Our numerical results for a Rb condensate close to a Si grating show that the resulting quantum vacuum torque is strong enough to provide a contactless transfer of angular momentum to the condensate and generate quantized vortices under realistic experimental conditions at separation distances around $3$ microns.Comment: 5 pages, 2 figures. Comparison with the results given by the pairwise summation approach added in the second figure. Accepted for publication in the Euro Physics Letter

Necesidades, intereses, barreras y atributos de un profesor investigador

Este trabajo da cuenta del proceso que se realizó durante un año, acerca de encontrar los elementos que constituyen a un profesor investigador, como las necesidades, intereses barreras y atributos, para lo cual se realizaron tres estudios de caso a tres profesoras de matemáticas de educación básica y media de Bogotá, realizando observaciones y entrevistas para recolectar información que posteriormente se analizarla y llegar a algunas conclusiones acerca de dichos elementos

A representação da comida e da bebida alcoólica na série justiça: efeitos e sentidos em uma série da televisão brasileira

Este projeto de pesquisa objetiva, por meio de um estudo de caso, refletir sobre as relações entre comunicação e consumo, tomando como referência o conceito de texto visual. A partir desse conceito, procura-se analisar a pertinência teórica desse enfoque, tendo em vista o que espera a sociedade midiática na representação da bebida alcoólica em uma série de televisão brasileira. Por meio de uma observação crítica do corpus da pesquisa, formado por fonte audiovisual, a série da Rede Globo Justiça, o trabalho tem como linha entender como é inserida na trama e na concepção de estrutura de personagem a bebida alcoólica

Estimación de ancho de banda disponible por generación de paquetes de prueba a través de NetFPGA

Estimate the available bandwidth required of appropriate measurements and analysis of packet flows produced and the measures contained in them, errors associated with generating and receiving test packets cannot be controlled and are outside the scope of tools estimation. Incorrect timestamp of test packets, using standard network card, the not using the real capacity of transmission of the network interfaces, receiving packets out of order, replication, packet corruption, among others, hinder the correct measurement of available bandwidth. The interchange of process in the operating system ago to be added unnecessary time between sending test packets and therefore are added errors in estimating the available bandwidth. The purpose of this article is to design a mechanism that allows for the generation of test packets at the hardware level using a technology called NetFPGA. This platform allows you to modify their behavior by having programmable logic arrays to generate and transmit packets to the link speed and in turn, interact with the software tool called Traceband estimate. The results raised the various modules for generating test packets and dialing the timestamp sent to the RAM of the NetFPGA; In addition to describing how the NetFPGA and Traceband must communicate it is through Traceband Register module.Estimar el ancho de banda disponible requiere mediciones y análisis adecuados de los flujos de paquetes producidos donde, errores asociados a la generación y recepción de paquetes de prueba son complejos de controlar y en algunos casos están fuera del alcance de las herramientas de estimación. La marcación incorrecta de los paquetes, el uso de tarjetas de red estándar, el no uso de la capacidad real de transmisión, la recepción de los paquetes fuera de orden, la replicación, la manipulación inadecuada de las herramientas de estimación, entre otros, obstaculizan la correcta medición del ancho de banda disponible. A su vez, el rendimiento y precisión impuestos por el sistema operativo, el cual no permite dar prioridad al proceso a la generación, envío y recepción de los paquetes de prueba, son procesos complejos de controlar y en algunos casos están fuera del alcance de las herramientas de estimación. A continuación, se presenta el diseño de una herramienta que permite la generación de paquetes de prueba a nivel de hardware utilizando NetFPGA. Esta plataforma permite modificar su comportamiento por los arreglos lógicos programables que posee para generar y transmitir paquetes a velocidad del enlace e interactúa con la herramienta software de estimación de ancho de banda disponible llamada Traceband. Su diseño contiene diversos módulos que realizan la generación de los paquetes de prueba, la marcación del timestamp de envío de los paquetes de prueba y describe la forma en que la NetFPGA y Traceband se comunican a través del módulo Traceband Register

NUEVAS TENDENCIAS EN EL DESARROLLO DE DESTINOS TURÍSTICOS: MARCOS CONCEPTUALES Y OPERATIVOS PARASU PLANIFICACIÓN Y GESTIÓN

     The continuous quantitative growth of tourism has been accompanied in the last decades by profound qualitative changes. This new scenario makes us rethink periodically our offer, in order to give an adequate respond to the new demands of the tourists. It is obvious that these changes in the consumer behaviour also force us to design new strategies. The traditional model based on product development has been substituted by a more complex marketplace, which leads us to considerate tourist destination as a whole. This report analyses how these changes are taking place and how the methodologies and planning processes should evolve. The aim of this paper is to help complex sustainable tourism destinations in their planning and development task, so that they can better find their market niches and compete against sound and competitive tourist products.     El continuo crecimiento cuantitativo del turismo está siendo acompañado en las últimas décadas de profundos cambios cualitativos, que obligan a pensar periódicamente la oferta con el fin de adaptarla a los nuevos gustos y demandas de los consumidores. Es evidente que estos cambios implican la reformulación de las estrategias y los procesos tradicionales de desarrollo, pasándose de manera general de planteamientos para la creación de productos a un marco de intervención más complejo en el que sea obligado atender a la totalidad del destino turístico. El presente trabajo analiza cómo se están produciendo estos cambios, y cómo deberían evolucionar las metodologías y los procesos de planificación con el fin de atender al desarrollo de destinos complejos, sostenibles y con capacidad para abrirse un hueco competitivo frente a productos sólidamente posicionados

Estimation of available bandwidth by generation of test packets through NetFPGA

Estimar el ancho de banda disponible requiere mediciones y análisis adecuados de los flujos de paquetes producidos donde, errores asociados a la generación y recepción de paquetes de prueba son complejos de controlar y en algunos casos están fuera del alcance de las herramientas de estimación. La marcación incorrecta de los paquetes, el uso de tarjetas de red estándar, el no uso de la capacidad real de transmisión, la recepción de los paquetes fuera de orden, la replicación, la manipulación inadecuada de las herramientas de estimación, entre otros, obstaculizan la correcta medición del ancho de banda disponible. A su vez, el rendimiento y precisión impuestos por el sistema operativo, el cual no permite dar prioridad al proceso a la generación, envío y recepción de los paquetes de prueba, son procesos complejos de controlar y en algunos casos están fuera del alcance de las herramientas de estimación. A continuación, se presenta el diseño de una herramienta que permite la generación de paquetes de prueba a nivel de hardware utilizando NetFPGA. Esta plataforma permite modificar su comportamiento por los arreglos lógicos programables que posee para generar y transmitir paquetes a velocidad del enlace e interactúa con la herramienta software de estimación de ancho de banda disponible llamada Traceband. Su diseño contiene diversos módulos que realizan la generación de los paquetes de prueba, la marcación del timestamp de envío de los paquetes de prueba y describe la forma en que la NetFPGA y Traceband se comunican a través del módulo Traceband Register.Estimate the available bandwidth required of appropriate measurements and analysis of packet flows produced and the measures contained in them, errors associated with generating and receiving test packets cannot be controlled and are outside the scope of tools estimation. Incorrect timestamp of test packets, using standard network card, the not using the real capacity of transmission of the network interfaces, receiving packets out of order, replication, packet corruption, among others, hinder the correct measurement of available bandwidth. The interchange of process in the operating system ago to be added unnecessary time between sending test packets and therefore are added errors in estimating the available bandwidth. The purpose of this article is to design a mechanism that allows for the generation of test packets at the hardware level using a technology called NetFPGA. This platform allows you to modify their behavior by having programmable logic arrays to generate and transmit packets to the link speed and in turn, interact with the software tool called Traceband estimate. The results raised the various modules for generating test packets and dialing the timestamp sent to the RAM of the NetFPGA; In addition to describing how the NetFPGA and Traceband must communicate it is through Traceband Register module

The self-regulatory German health care system between growing competition and state hierarchy

This article focuses on the changing role of the state in financing, providing and regulating health care services under the German health care system from 1970-2000. While a reduced role of the state can be observed in terms of financing, our analysis of service provision indicates inconsistent developments. Monetary resource flow analyses indicate a decrease in private service provision as a percentage of total health expenditure, but when analysing the development of health employment we see a growth in “private” health care personnel. The most important changes, however, have taken place in terms of regulation. Since the early 1990s, the traditionally self-regulatory German health care system has simultaneously faced growing competition and state hierarchy

Effect of the electrophoretic deposition of Au NPs in the performance CdS QDs sensitized solar cells

Solution-processed mesoscopic oxide semiconductor-based materials offer potentially low-cost and high stability alternative for next generation of solar cells, and metallic nanoparticles had shown to be a good alternative to improve specific parameters in such kind of devices. In the present work, it is showed the systematic study of the effect of electrophoretic gold nanospheres (Au NPs) with cadmium sulfide Quantum Dots (CdS QDs) sensitized TiO2 solar cells. Au NPs were added by electrophoretic deposition at several times (0.5, 2.5 and 7.5 minutes) and CdS QDs were deposited by a Successive Ionic Layer Absorption and Reaction (SILAR) method. Electrophoretic deposition allowed to significantly decrease the Au NPs deposition times respect previously reported methods. The results show that Au NPs reduce the photocurrent (from 9.85 to 9.44 mA/cm2) at the same time that increase the open circuit voltage (Voc) (from 575 to 618 mV) and the Fill Factor (FF) (from 46 to 51%) which result in a final increase of the photoconversion efficiency (η) (from 2.63 to 2.96% for 0.5 min of deposit). A systematic characterization permitted to identify the origin of the variations observed in the solar cell parameters with and without Au NPs. Incident Photon to Current conversion efficiency (IPCE) demonstrate that the Au NPs reduces the amount of light that reach the CdS QDs and Impedance Spectroscopy (IS) analysis, indicates a downshift in the TiO2 conduction band (CB) and decreases the recombination processes, resulting in the observed increase in the FF and Voc.We acknowledge financial support from CONACYT through grant 134111, the UC-MEXUS program grant 00007, the European Community Seven Framework Program (FP7- 428 NMP-2010-EU-MEXICO), CIO-UGTO 2013–2015 and the CEMIE-Solar (04002) consortium. D. Esparza, and A. Ceja acknowledge scholarship from CONACYT and thanks to Maria Christian Albor for SEM and EDS analysis. Isaac Zarazúa thanks to CONACYT for the postdoctoral fellow