Generation of maximally entangled states of qudits using twin photons

We report an experiment to generate maximally entangled states of D-dimensional quantum systems, qudits, by using transverse spatial correlations of two parametric down-converted photons. Apertures with D-slits in the arms of the twin fotons define the qudit space. By manipulating the pump beam correctly the twin photons will pass only by symmetrically opposite slits, generating entangled states between these differents paths. Experimental results for qudits with D=4 and D=8 are shown. We demonstrate that the generated states are entangled states.Comment: 04 pages, 04 figure

Propagation of spatially entangled qudits through free space

We show the propagation of entangled states of high-dimensional quantum systems. The qudits states were generated using the transverse correlation of the twin photons produced by spontaneous parametric down-conversion. Their free-space distribution was performed at the laboratory scale and the propagated states maintained a high-fidelity with their original form. The use of entangled qudits allow an increase in the quantity of information that can be transmitted and may also guarantee more privacy for communicating parties. Therefore, studies about propagating entangled states of qudits are important for the effort of building quantum communication networks.Comment: 5 Pages, 4 Figures, REVTeX

Current Trends of Teaching Computer Programming in Undergraduate CS Programs: A Survey from Ecuadorian Universities

Abstract. Computer programming has become a relevant element of the modern era. Practically it is involved in all sectors of modern society. Currently, many universities around the globe offer bachelor’s degree programs that contain computer programming related courses. In order to gain insight into how computer programming is taught in Ecuadorian Higher Education Institutions (HEIs), we have conducted the first national survey on teaching computer programming in undergraduate CS programs. In this survey participated 53 respondents from 13 Ecuadorian HEIs. We report on programming paradigms, programming languages, integrated development environments and teaching strategies used in the programming learning process. We found that the object-oriented paradigm along with the Java programming language are the most often used. The NetBeans integrated development environment is the most commonly used among the respondents. Concerning teaching strategies, e-learning platforms are commonly used as part of computer programming courses. More than half of the respondents use collaborative strategies such as pair programming in their courses. Finally, a half of the respondents use traditional computer labs for teaching programming; however, other approaches such as mobile devices, games and simulations, Arduino kits and robots start to be used as a teaching strategy. Our findings can serve as a starting point for addressing reforms in computer programming courses taught in Ecuadorian CS undergraduate programs

Super-poissonian photon statistics and correlations between pump and probe fields in Electromagnetically Induced Transparency

We have measured the photon statistics of pump and probe beams after interaction with Rb atoms in a situation of Electromagnetically Induced Transparency. Both fields present super-poissonian statistics and their intensities become correlated, in good qualitative agreement with theoretical predictions in which both fields are treated quantum-mechanically. The intensity correlations measured are a first step towards the observation of entanglement between the fields.Comment: 4 pages, two-column, 4 figures, first submitted to PRL on Aug. 6, 200

Laser-noise-induced correlations and anti-correlations in Electromagnetically Induced Transparency

High degrees of intensity correlation between two independent lasers were observed after propagation through a rubidium vapor cell in which they generate Electromagnetically Induced Transparency (EIT). As the optical field intensities are increased, the correlation changes sign (becoming anti-correlation). The experiment was performed in a room temperature rubidium cell, using two diode lasers tuned to the $^{85}$Rb $D_2$ line ($\lambda = 780$nm). The cross-correlation spectral function for the pump and probe fields is numerically obtained by modeling the temporal dynamics of both field phases as diffusing processes. We explored the dependence of the atomic response on the atom-field Rabi frequencies, optical detuning and Doppler width. The results show that resonant phase-noise to amplitude-noise conversion is at the origin of the observed signal and the change in sign for the correlation coefficient can be explained as a consequence of the competition between EIT and Raman resonance processes.Comment: Accepted for publication in EPJ

Micronúcleos y otras anormalidades nucleares en células de mucosa bucal como biomarcadores de genotoxicidad y citotoxicidad en personal expuesto a gases anestésicos

Associated damage to health during occupational exposition is a controvert issue. It has been reported either reproductive toxicity, affections to organs, cancer and genotoxicity. Objective: To evaluate micronuclei and other nuclear abnormalities frequencies at epithelial mouth cells from people exposed to anesthetic gasses as genotoxicity and cytotoxicity markers. Methodology: We gathered a total of 164 epithelial mouth samples from 81 anesthesiologists from different Mexican Health clinics across, 43 health people not exposed and with no addictions and 40 patients receiving antineoplastic drugs. The survey included questions related with habits, work location and schedules and general data that could be related with results. Epithelial cell smears were obtained with gentle scraping, dried and fixed with 80% ethylic alcohol and stained with orcein and fast green. We analyzed 2,000 cells from each sample under microscope (100x) and counted for Micronucleated cells (CMN) and Nuclear abnormalities (AN) [Binucleated (CBN), Lobulated nucleus (NL), Karyorrhexis (CR), condensed chromatin (CC), Pyknosis (PN) and Karyolysis (CL)]. Results: Counts from anesthesiologists MN were statistically higher than not exposed [2.8(1.9)/ 0.7(0.7)/ 1,000 cells, (p: <0.001)]. No matter of exposition time, age or sex, 86% of the anesthesiologists presented micronucleus genotoxicity and the complement presented cytotoxicity. Conclusions: Occupational exposition to anesthetic gases at Mexican health clinics system induces genotoxic and cytotoxic damage been evident by the MN and AN count at mouth epithelial cells. We highly recommend increasing security measures.El daño a la salud asociado a exposición ocupacional de anestésicos es controversial, se ha encontrado toxicidad reproductiva, afección de órganos, cáncer y genotoxicidad. Objetivo: Evaluar la frecuencia de micronúcleos y otras anormalidades nucleares en células de mucosa bucal de personal expuesto a gases, como marcadores de genotoxicidad y citotoxicidad. Métodología: Se colectaron 164 muestras de mucosa bucal de 81 anestesiólogos que laboraban en diferentes hospitales en México, 43 personas sanas no expuestas y sin toxicomanías, y 40 pacientes tratados con antineoplásicos. Se preguntó hábitos, lugar y horas de trabajo, sistemas de eliminación de gases del centro de trabajo y datos que podrían influir en los resultados. Se realizaron frotis de mucosa bucal mediante un raspado suave, se dejaron secar, se fijaron con etanol al 80% y se tiñeron con orceína y verde rápido. Al microscopio (100X), por muestra se analizaron 2,000 células, se identificaron células micronucleadas (CMN) y anormaliades nucleares (AN) [binucleadas (CBN), núcleo lobulado (NL), cariorrexis (CR), cromatina condensada (CC), picnosis (PN) y cariólisis (CL)]. Resultados: La frecuencia de CMN es mayor en anestesiólogos que en no expuestos, [2.8 (1.9)/ 0.7(0.7)/ 1,000 células, (p: <0.001)]. Independiente de tiempo de exposición, lugar de trabajo, edad o sexo, en el 86.4% de anestesiólogos se observó micronucleogenicidad y en el resto citotoxicidad. Conclusiones: La exposición ocupacional a gases anestésicos en el ambiente hospitalario mexicano induce daño genotóxico y citotóxico evidenciado por presencia de MN y AN en células exfoliadas de mucosa bucal, por ello se sugiere reforzar las medidas de seguridad

Innovación educativa con tecnologías emergentes en el contexto de las prácticas educativas abiertas

Las Tecnologías de la Información y la Comunicación (TIC) modifican las prácticas sociales e influyen en diferentes ámbitos de la vida cotidiana. En la actual Sociedad del Conocimiento, éste se entiende subjetivo, dinámico y producido colaborativamente. La conectividad se constituye en un aspecto clave: permite a los individuos crear y distribuir sus propios materiales, incorporar nuevas ideas, tecnologías y tendencias de uso, permitiendo a los docentes adoptar modelos y metodologías innovadoras. La integración de la tecnología puede promover cambios en el sistema educativo al impactar en las prácticas. Los Recursos Educativos Abiertos (REA), surgen como iniciativa para compartir materiales digitales disponibles en la web de forma libre y gratuita, utilizables en el ámbito académico y de investigación de todo el mundo. A partir de los REA surgen las Prácticas Educativas Abiertas (PEA), las que apoyan la producción, utilización y reutilización de REA de alta calidad a través de políticas institucionales y modelos pedagógicos innovadores. Con la adopción de las nuevas tecnologías se requiere el desarrollo de nuevas teorías, métodos, enfoques de enseñanza, evaluación y organización. Las relaciones entre las pedagogías emergentes y las tecnologías emergentes producen un doble vínculo: algunas tecnologías desarrolladas sin una finalidad educativa específica se usan con fines educativos y las prácticas pedagógicas se modifican transformando las prestaciones tecnológicas. Las tecnologías emergentes resultan mediadoras de los procesos de cambio y la innovación educativa es el camino para avanzar hacia la calidad. Este proyecto tiene por objetivo: Analizar, diseñar e implementar Modelos Pedagógicos y Estrategias Didácticas para el desarrollo de PEA, aplicado a prácticas educativas innovadoras con tecnologías emergentes, mediante la metodología propia de la Investigación-Acción y con el objetivo amplio de explorar estrategias de mejora para el sistema educativo y social. EL grupo de trabajo se plantea un doble propósito: el de investigación, para generar conocimiento y comprensión y el de acción, para potenciar la reflexión de las prácticas educativas. Se espera que docentes de distintos niveles educativos experimenten las PEA como diseños instruccionales y como objetos mediadores en la apropiación del conocimiento, para impactar en los métodos y estrategias de enseñanza con vistas a que esas prácticas puedan ser replicadas.Eje: Innovación en Educación Informática.Red de Universidades con Carreras en Informátic

Operations of and Future Plans for the Pierre Auger Observatory

Technical reports on operations and features of the Pierre Auger Observatory, including ongoing and planned enhancements and the status of the future northern hemisphere portion of the Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200