The Transit Light Curve project. XIV. Confirmation of Anomalous Radii for the Exoplanets TrES-4b, HAT-P-3b, and WASP-12b

We present transit photometry of three exoplanets, TrES-4b, HAT-P-3b, and WASP-12b, allowing for refined estimates of the systems' parameters. TrES-4b and WASP-12b were confirmed to be "bloated" planets, with radii of 1.706 +/- 0.056 R_Jup and 1.736 +/- 0.092 R_Jup, respectively. These planets are too large to be explained with standard models of gas giant planets. In contrast, HAT-P-3b has a radius of 0.827 +/- 0.055 R_Jup, smaller than a pure hydrogen-helium planet and indicative of a highly metal-enriched composition. Analyses of the transit timings revealed no significant departures from strict periodicity. For TrES-4, our relatively recent observations allow for improvement in the orbital ephemerides, which is useful for planning future observations.Comment: AJ, in press [11 pages]; corrected error in distance to WASP-1

Towards spin injection from silicon into topological insulators: Schottky barrier between Si and Bi2Se3

A scheme is proposed to electrically measure the spin-momentum coupling in the topological insulator surface state by injection of spin polarized electrons from silicon. As a first approach, devices were fabricated consisting of thin (<100nm) exfoliated crystals of Bi2Se3 on n-type silicon with independent electrical contacts to silicon and Bi2Se3. Analysis of the temperature dependence of thermionic emission in reverse bias indicates a barrier height of 0.34 eV at the Si-Bi2Se3 interface. This robust Schottky barrier opens the possibility of novel device designs based on sub-band gap internal photoemission from Bi2Se3 into Si

USE OF SYNTHETIC TANINES DURING THE SKIN CURTITION PROCESS OF Cavia porcellus (CUY) IN FINE PELETERY

The Cavia porcellus skin (Cuy), after receiving a tanning process, using synthetic tannins, becomes a high quality leather, very suitable in the articles manufacture of high quality. Its main objective was the evaluation of different levels of synthetic tannin (6, 7, 8%) during the tanning process of guinea pig skins with hair; using 48 skins, with an average mass of 200 g each. The experimental units modeled with a Completely Random Design (DCA. Once the experimental phase was completed, it observed that the most skin tanning suitable level the guinea pig (retaining hair) is 6 % of synthetic tanning agent; it´s supported by the excellent results the tests performed. The physical resistance evaluation determined that the best tensile strength (1945.75 N/cm2) it´s reached whit 6 % of synthetic tannin and the best percentage of elongation (89.69 %) achieved with the use of 7 % of tannin (which fully meet the requirements quality the Spanish Leather Association). The most efficient sensorial characteristics obtained with 6 % of tannin: fullness 4.88; softness 4.63 and roundness 4.75 points, respectively; producing a very soft, flexible skin and above all with the fullness suitable for the fine articles manufacture. Keywords: tanning, skins, guinea pig, synthetic tannins. Resumen La piel del Cavia porcellus (Cuy), después de curtida, empleando taninos sintéticos, se convierte en un cuero de alta calidad, muy adecuado en la peletería fina. Esta investigación tuvo por objetivo fundamental la evaluación de diferentes niveles de tanino sintético (6, 7, 8 %) durante el proceso de curtición de pieles de cuyes con pelo; utilizando para ello un total de 48 pieles, con una masa promedio de 200 g cada una. Las unidades experimentales fueron modeladas con un Diseño Completamente al Azar (DCA). Una vez culminada la fase experimental, se pudo constatar que el nivel más adecuado para la curtición de la piel de cuy (conservando el pelo) es del 6 % de curtiente sintético; lo cual quedó avalado por los excelentes resultados de las pruebas practicadas. La evaluación de las resistencias físicas determinó que la mejor resistencia a la tensión (1945,75 N/cm2) se alcanzó al curtir con 6 % de tanino sintético, y el mejor porcentaje de elongación (89,69 %), se logró con la utilización de 7 % de tanino (que satisfacen completamente con las exigencias de calidad de la Asociación Española del Cuero). Las características sensoriales más eficientes fueron logradas al curtir las pieles con 6 % de tanino: llenura 4,88; blandura 4,63 y redondez 4,75 puntos, respectivamente; produciéndose una piel muy suave, flexible y sobre todo con la llenura adecuada para la confección de artículos de peletería fina. Palabras Clave: Clave: curtición, pieles, cuy, taninos sintéticos

Dialectical Interrelation Between: Problematic Situation, Real Problem, Scientific Problem, Object and Field, in the Investigation Design: A Necessary Reflection

All research responds to the need of solutions to a problem that directly or indirectly affects society. The development of the same largely certifies and determines the constant search for solutions. The main objective of the present study was to arrive at a clear conceptualization, as complete as possible, of some the most important terms that come up during an investigation design: Problematic Situation, Real Problem, Scientific Problem, and Object and Field, given the visible shortcomings observed in pre- and post-graduate theses when the research work is being developed and defended. The methodology consisted of basically developing a reflection around these terms (the vision that different authors have in this regard was very helpful), as well as the presentation of varied examples contributed to see the meaning of these important concepts more clearly. The study shows in a scientifically grounded way the achievement of the above. The way in which the presentation of the different concepts was handled removes any possibility of mistakes. Keywords: methodology scientific investigation, problem, object, field. Resumen Toda investigación parte del apremio en dar una respuesta a la solución de un problema que afecta de una manera directa o indirecta a la Sociedad. En gran medida, el propio desarrollo de la misma compulsa y determina esa constante búsqueda de soluciones. El objetivo principal del presente estudio fue llegar a una conceptualización clara, y lo más acabada posible, de algunos de los más importantes términos que se manejan durante el diseño de una investigación: Situación Problémica, Problema Real, Problema Científico, Objeto y Campo, dada las visibles falencias que se observan en tesistas de pre y postgrado a la hora de desarrollar y defender sus trabajos de investigación. La metodología consistió, básicamente, en desarrollar una reflexión en torno a estos términos; para lo cual resultó de gran ayuda la visión que tienen diferentes autores al respecto; así como, la exposición de variados ejemplos contribuyó a ver más definidamente el significado de estos importantes conceptos. El estudio muestra de forma científicamente fundamentada el logro de lo anterior. La forma en que se maneja la presentación de los diferentes conceptos aleja toda posibilidad de equívocos. Palabras clave: metodología investigación científica, problema, objeto, campo

Calculation of the interventilatory threshold area: a method for examining the aerobic-anaerobic transition

El objetivo fue determinar la relación entre el área interumbrales (ITA) [la zona comprendida entre el primer y el segundo umbral ventilatorio (VT1 y VT2) en la función VO2/VE, Carga/VO2 y Carga/VE] y las variables ergoespirométricas. Treinta y tres hombres realizaron un test incremental. El ITA se calculó: 1) como la integral definida por el área entre VT1 y VT2 bajo las curvas de VO2/VE, Carga/VO2 y Carga/VE y 2) como la suma de las áreas descritas por el triángulo y rectángulo entre los mismos puntos. El ITA para la función Carga/VE se correlacionó positivamente (p<0,01) con la carga en VT2 (r = 0,831) y la ventilación en VT2 (r = 0,799). El ITA para la función VO2/VE fue significativamente mayor en los ciclistas que en los estudiantes. La determinación del ITA es un método simple para evaluar la transición aeróbica-anaeróbica durante las pruebas de esfuerzo incremental.The aim was to determine the relationship between the interthreshold area (ITA) [the area between the first and second ventilatory threshold (VT1 and VT2) for the function VO2/VE, load/VO2 and load/VE] and the traditional variables measured. Thirty-three men underwent an incremental test. The ITA was calculated: 1) as the integral defined by the area between VT1 and VT2 under the curves for the functions VO2/VE, load/VO2 and load/VE and 2) as the simple sum of the areas described by the triangle and rectangle between the same points. The mean ITA for the function load/VE was positively correlated (p<0.01) with load at VT2 (r=0.831) and ventilation at VT2 (r=0.799). The mean ITA for the function VO2/VE was significantly greater in the cyclists than in the students. The ITA for the function load/VE differed between March and July as training progressed. The determination of the ITA is a simple method of assessing the aerobic-anaerobic transition process during incremental exercise tests

Kepler-47: A Transiting Circumbinary Multi-Planet System

We report the detection of Kepler-47, a system consisting of two planets orbiting around an eclipsing pair of stars. The inner and outer planets have radii 3.0 and 4.6 times that of the Earth, respectively. The binary star consists of a Sun-like star and a companion roughly one-third its size, orbiting each other every 7.45 days. With an orbital period of 49.5 days, eighteen transits of the inner planet have been observed, allowing a detailed characterization of its orbit and those of the stars. The outer planet's orbital period is 303.2 days, and although the planet is not Earth-like, it resides within the classical "habitable zone", where liquid water could exist on an Earth-like planet. With its two known planets, Kepler-47 establishes that close binary stars can host complete planetary systems.Comment: To appear on Science Express August 28, 11 pages, 3 figures, one table (main text), 56 pages, 28 figures, 10 table

Size of the Vela Pulsar's Radio Emission Region: 500 km

We use interstellar scattering of the Vela pulsar to determine the size of its emission region. From interferometric phase variations on short baselines, we find that radio-wave scattering broadens the source by 3.4+/-0.3 milliarcseconds along the major axis at position angle 81+/-3 degrees. The ratio of minor axis to major axis is 0.51+/-0.03. Comparison of angular and temporal broadening indicates that the scattering material lies in the Vela-X supernova remnant surrounding the pulsar. From the modulation of the pulsar's scintillation on very short baselines, we infer a size of 500 km for the pulsar's emission region. We suggest that radio-wave refraction within the pulsar's magnetosphere may plausibly explain this size.Comment: 14 pages, includes 2 figures. Also available at: http://charm.physics.ucsb.edu:80/people/cgwinn/cgwinn_group/cgwinn_group.htm

Pinning and switching of magnetic moments in bilayer graphene

We examine the magnetic properties of the localized states induced by lattice vacancies in bilayer graphene with an unrestricted Hartree-Fock calculation. We show that with realistic values of the parameters and for experimentally accessible gate voltages we can have a magnetic switching between an unpolarized and a fully polarized system.Comment: 9 pages, 4 figure