Sharp values for the constants in the polynomial Bohnenblust-Hille inequality

In this paper we prove that the complex polynomial Bohnenblust-Hille constant for $2$-homogeneous polynomials in ${\mathbb C}^2$ is exactly $\sqrt[4]{\frac{3}{2}}$. We also give the exact value of the real polynomial Bohnenblust-Hille constant for $2$-homogeneous polynomials in ${\mathbb R}^2$. Finally, we provide lower estimates for the real polynomial Bohnenblust-Hille constant for polynomials in ${\mathbb R}^2$ of higher degrees.Comment: 16 page

Neogene to recent contraction and basin inversion along the Nubia-Iberia boundary in SW Iberia

The SW of Iberia is currently undergoing compression related to the convergence between Nubia and Iberia. Multiple compressive structures, and their related seismic activity, have been documented along the diffuse Nubia-Iberia plate boundary, including the Gorringe bank west of the Gulf of Cadiz, and the Betic-Rif orogen to the east. Despite seismic activity indicating a dominant compressive stress along the Algarve margin in the Gulf of Cadiz, the structures at the origin of this seismicity remain elusive. This paper documents the contractional structures that provide linkage across the Gulf of Cadiz and play a major role in defining the present-day seismicity and bathymetry of this area. The structures described in this paper caused the Neogene inversion of the Jurassic oblique passive margin that formed between the central Atlantic and the Ligurian Tethys. This example of a partially inverted margin provides insights into the factors that condition the inversion of passive margins

Low-loss inverted taper edge coupler in silicon nitride

"This paper is a postprint of a paper submitted to and accepted for publication in IET Optoelectronics and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library"[EN] An inverted lateral taper with one vertical discrete step was designed for a medium confinement silicon nitride waveguide platform in the C-band, as a chip edge coupler, with a predicted insertion loss of 0.58¿dB. The design is supported by an extensive study to evaluate the impact of fabrication process variations on the performance of such a coupler. The device was manufactured and measured, showing an insertion loss of 1.47 dB, which was traced back to fabrication process variations as cross-checked with simulations. To the authors¿ knowledge, the reported edge coupler is the shortest and among the best performing found for silicon nitride platforms.The authors acknowledge financial support through projects TEC2015-69787-REDT PIC4TB, TEC2016-80385-P SINXPECT, TEC2014-54449-C3-1-R, GVA PROMETEO 2017/103, EC H2020-ICT-27-2015 PICs4all CSA 68777.Fernández-Vicente, J.; Baños Lopez, R.; Doménech Gómez, JD.; Domínguez-Horna, C.; Muñoz Muñoz, P. (2019). Low-loss inverted taper edge coupler in silicon nitride. IET Optoelectronics. 13(2):62-66. https://doi.org/10.1049/iet-opt.2018.5065S6266132Marcatili, E. A. J. (1969). Dielectric Rectangular Waveguide and Directional Coupler for Integrated Optics. Bell System Technical Journal, 48(7), 2071-2102. doi:10.1002/j.1538-7305.1969.tb01166.xMiller, S. E. (1969). Integrated Optics: An Introduction. Bell System Technical Journal, 48(7), 2059-2069. doi:10.1002/j.1538-7305.1969.tb01165.xTomlinson, W. J., & Brackett, C. A. (1987). Telecommunications applications of integrated optics and optoelectronics. Proceedings of the IEEE, 75(11), 1512-1523. doi:10.1109/proc.1987.13912Lim, A. E.-J., Junfeng Song, Qing Fang, Chao Li, Xiaoguang Tu, Ning Duan, … Tsung-Yang Liow. (2014). Review of Silicon Photonics Foundry Efforts. IEEE Journal of Selected Topics in Quantum Electronics, 20(4), 405-416. doi:10.1109/jstqe.2013.2293274Smit, M., Leijtens, X., Ambrosius, H., Bente, E., van der Tol, J., Smalbrugge, B., … van Veldhoven, R. (2014). An introduction to InP-based generic integration technology. Semiconductor Science and Technology, 29(8), 083001. doi:10.1088/0268-1242/29/8/083001Taillaert, D., Bogaerts, W., Bienstman, P., Krauss, T. F., Van Daele, P., Moerman, I., … Baets, R. (2002). An out-of-plane grating coupler for efficient butt-coupling between compact planar waveguides and single-mode fibers. IEEE Journal of Quantum Electronics, 38(7), 949-955. doi:10.1109/jqe.2002.1017613Dillon, T., Murakowski, J., Shi, S., & Prather, D. (2008). Fiber-to-waveguide coupler based on the parabolic reflector. Optics Letters, 33(9), 896. doi:10.1364/ol.33.000896Li, H., Cao, Z., Lu, H., & Shen, Q. (2003). Free-space coupling of a light beam into a symmetrical metal-cladding optical waveguide. Applied Physics Letters, 83(14), 2757-2759. doi:10.1063/1.1616205Cardenas, J., Poitras, C. B., Luke, K., Luo, L.-W., Morton, P. A., & Lipson, M. (2014). High Coupling Efficiency Etched Facet Tapers in Silicon Waveguides. IEEE Photonics Technology Letters, 26(23), 2380-2382. doi:10.1109/lpt.2014.2357177Shiraishi, K., Yoda, H., Ohshima, A., Ikedo, H., & Tsai, C. S. (2007). A silicon-based spot-size converter between single-mode fibers and Si-wire waveguides using cascaded tapers. Applied Physics Letters, 91(14), 141120. doi:10.1063/1.2795337Tao, H., Song, J., Fang, Q., Yu, M., Lo, G., & Kwong, D. (2008). Improving coupling efficiency of fiber-waveguide coupling with a double-tip coupler. Optics Express, 16(25), 20803. doi:10.1364/oe.16.020803Muñoz, P., Micó, G., Bru, L., Pastor, D., Pérez, D., Doménech, J., … Domínguez, C. (2017). Silicon Nitride Photonic Integration Platforms for Visible, Near-Infrared and Mid-Infrared Applications. Sensors, 17(9), 2088. doi:10.3390/s17092088Papes, M., Cheben, P., Benedikovic, D., Schmid, J. H., Pond, J., Halir, R., … Vašinek, V. (2016). Fiber-chip edge coupler with large mode size for silicon photonic wire waveguides. Optics Express, 24(5), 5026. doi:10.1364/oe.24.005026Cheben, P., Schmid, J. H., Wang, S., Xu, D.-X., Vachon, M., Janz, S., … Picard, M.-J. (2015). Broadband polarization independent nanophotonic coupler for silicon waveguides with ultra-high efficiency. Optics Express, 23(17), 22553. doi:10.1364/oe.23.022553Shani, Y., Henry, C. H., Kistler, R. C., Orlowsky, K. J., & Ackerman, D. A. (1989). Efficient coupling of a semiconductor laser to an optical fiber by means of a tapered waveguide on silicon. Applied Physics Letters, 55(23), 2389-2391. doi:10.1063/1.102290Zhuang, L., Marpaung, D., Burla, M., Beeker, W., Leinse, A., & Roeloffzen, C. (2011). Low-loss, high-index-contrast Si_3N_4/SiO_2 optical waveguides for optical delay lines in microwave photonics signal processing. Optics Express, 19(23), 23162. doi:10.1364/oe.19.02316

Intervalo entre partos en el vacuno de carne extensivo de raza retinta

La eficacia reproductiva en el vacuno depende, entre otros parámetros, del intervalo entre partos. Esta variable está considerada una de las más importantes para la rentabilidad de la explotación en el caso del vacuno de carne en régimen extensivo. En este trabajo se estudia la influencia de distintos factores sobre el intervalo entre partos en la raza retinta mediante el análisis de 7356 partos de 1803 vacas pertenecientes al Núcleo de Control de Rendimientos de la Asociación de Ganaderos de esta raza. Nuestros resultados muestran que este parámetro se ve afectado principalmente por la ganadería, la campaña ganadera, época, sus interacciones y el tipo de parto, no existiendo relación significativa entre este período y el peso al destete de los terneros El valor medio obtenido para todo el intervalo analizado ha sido de 16,144 ± 0,086 meses y la heredabilidad estimada para este carácter fue de 0,1104 ± 0,08

Brief Results of a Trawl Experimental Survey at NW Atlantic

An experimental survey was carried out in NAFO Regulatory Area (Div. 6EFGH and 4XWVs) and adjacent international Southern waters during last Quarter of year 2004, with one polyvalent Spanish trawler, using "Gloria" pelagic gear and bottom gear, with the aim to obtain data on distribution and biology on pelagic and demersal species in non-habitual grounds for the Spanish fleet. A scientific observer was on board to collect the information on fishing activity (effort, depth, etc.) and biological data (length distributions, length-weight relationships, etc.). A total of 119 hauls were carried out. Samplings were conducted in a wide geographical and bathymetrical range. During the survey, Alfonsino (Beryx splendens) was the main caught species

Polynomial Inequalities on the π/4-Circle Sector

A number of sharp inequalities are proved for the space P (2D (π/4)) of 2-homogeneous polynomials on ℝ2 endowed with the supremum norm on the sector D (π/4) := {eiθ : θ ∈ [0, π/4]}. Among the main results we can find sharp Bernstein and Markov inequalities and the calculation of the polarization constant and the unconditional constant of the canonical basis of the space P (2D (π/4))

Quality procedures and ABP proposal in the subject of Pharmaceutical Management and Planning

Se diseña e implanta convenientemente una propuesta de aprendizaje basada en problema (ABP), donde el alumno se enfrente a una problemática real, consistente en incrementar la rentabilidad en una farmacia, y la presentación de la solución como procedimientos normalizados de trabajo (PNT). Objetivo: diseño y caracterización de la propuesta ABP en Gestión y Planificación Farmacéutica, dando a conocer la metodología desarrollada a la comunidad académica y contrastar los resultados con el fin de mejorarla. Metodología: incluye etapas del diseño detalladas y se determinan las repercusiones en la enseñanza. Se recogen las opiniones de los alumnos con cuestionario con ítems referentes a aspectos generales de la asignatura y datos específicos del ABP. Conclusiones: El ABP mejorar los resultados los alumnos, siendo la opinión favorables tanto en los aspectos generales como en cuestiones específicas del caso problema, incluso en los alumnos con puntuación más bajas que reconocen el interés del ABP en el contexto de la asignatura. Son mejorables la documentación y recursos tecnológicos utilizados.We implant a proposal for a Learning Based on Problems (LBP) methodology, where students are facing a real problem, in how to increase the profitability of a pharmacy, and the presentation of the solution as standard operating procedures (SOPs). Objective: To design and characterize the proposal PEL (Pharmaceutical Management and Planning), publicizing the methodology developed for the academic community and contrast the results to improve it. Methodology: includes detailed design stages and determining the impact on teaching. It also reflects the opinions of students with questionnaire items concerning general aspects of the subject and specifics of PBL. Conclusions: The PBL improve students’ results, being the favorable opinion in both the general and specific issues of the case problem.Este trabajo ha sido subvencionado dentro de la Convocatoria de Ayudas para la Divulgación de Proyectos de Investigación, Innovación y Mejora de la Actividad Docente, del II Plan Propio de Docencia, de la Universidad de Sevila