41 research outputs found

    Multi-wavelength laser based on an arrayed waveguide grating and Sagnac loop reflectors monolithically integrated on InP

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    In this paper, a multi-wavelength laser monolithically integrated on InP is presented. A linear laser cavity is built between two integrated Sagnac loop reflectors, with an Arrayed Waveguide Grating (AWG) as frequency selective device, and Semiconductor Optical Amplifiers (SOA) as gain sections. The power is out coupled from the cavity using a side diffraction order of the AWG. Simultaneous laser operation is provided for four wavelengths/cavities in the device. The termination of the laser cavities with integrated Sagnac loop reflectors avoids using high reflection coating. Only anti-reflection coating is used in the output facet of the chip

    InP monolithically integrated label swapper device for spectral amplitude coded optical packet networks

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    In this paper a label swapping device, for spectral amplitude coded optical packet networks, fully integrated using InP technology is presented. Compared to previous demonstrations using discrete component assembly, the device footprint is reduced by a factor of 105 and the operation speed is increased by a factor of 103. This is, to the best of our knowledge, the first demonstration of a totally integrated label swapping device

    Time of flight measurements based on FPGA using a breast dedicated PET

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    In this work the implementation of a Time-to-Digital Converter (TDC) using a Nutt delay line FPGA-based and applied on a Positron Emission Tomography (PET) device is going to be presented in order to check the system’s suitability for Time of Flight (TOF) measurements. In recent years, FPGAs have shown great advantages for precise time measurements in PET. The architecture employed for these measurements is described in detail. The system developed was tested on a dedicated breast PET prototype, composed of LYSO crystals and Positive Sensitive Photomultipliers (PSPMTs). Two distinct experiments were carried out for this purpose. In the first test, system linearity was evaluated in order to calibrate the time measurements, providing a linearity error of less than 2% and an average time resolution of 1.4 ns FWHM. The second set of measurements tested system resolution, resulting in a FWHM as good as 1.35 ns. The results suggest that the coincidence window for the current PET can be reduced in order to minimize the random events and thus, achieve better image qualityAguilar, A.; García Olcina, R.; Martos, J.; Soret, J.; Torres-Pais, J.; Benlloch Baviera, JM.; González Martínez, AJ.... (2014). Time of flight measurements based on FPGA using a breast dedicated PET. Journal of Instrumentation. 9:0-8. doi:10.1088/1748-0221/9/05/C05012S08

    Label swapper device for spectral amplitude coded optical packet networks monolithically integrated on InP

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    This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.19.013540. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawIn this paper the design, fabrication and experimental characterization of an spectral amplitude coded (SAC) optical label swapper monolithically integrated on Indium Phosphide (InP) is presented. The device has a footprint of 4.8x1.5 mm 2 and is able to perform label swapping operations required in SAC at a speed of 155 Mbps. The device was manufactured in InP using a multiple purpose generic integration scheme. Compared to previous SAC label swapper demonstrations, using discrete component assembly, this label swapper chip operates two order of magnitudes faster. © 2011 Optical Society of America.The activities have been carried out in the framework of the Joint Research Activity (JRA) 'Active-phased Arrayed Devices' (WP 44) of the European Commission FP6 Network of Excellence ePIXnet (European Network of Excellence on Photonic Integrated Components and Circuits), Project Reference: 004525, http://www.epixnet.org/. This work has been partially funded through the Spanish Plan Nacional de I+D+i 2008-2011 project TEC2008-06145/TEC. It has also been partially supported by the Canadian Institute for Photonic Innovations. Devices are presently being fabricated through the InP Photonic Integration Platform JePPIX (coordinator D J Robbins), at the COBRA fab, http://www.jeppix.eu/Muñoz Muñoz, P.; Garcia-Olcina, R.; Habib, C.; Chen, LR.; Leijtens, XJM.; De Vries, T.; Robbins, D.... (2011). Label swapper device for spectral amplitude coded optical packet networks monolithically integrated on InP. Optics Express. 19(14):13540-13550. https://doi.org/10.1364/OE.19.013540S13540135501914Yoo, S. J. B. (2006). Optical Packet and Burst Switching Technologies for the Future Photonic Internet. Journal of Lightwave Technology, 24(12), 4468-4492. doi:10.1109/jlt.2006.886060Blumenthal, D. J., Olsson, B.-E., Rossi, G., Dimmick, T. E., Rau, L., Masanovic, M., … Barton, J. (2000). All-optical label swapping networks and technologies. Journal of Lightwave Technology, 18(12), 2058-2075. doi:10.1109/50.908817Srivatsa, A., d. Waardt, H., Hill, M. T., Khoe, G. D., & Dorren, H. J. S. (2001). All-optical serial header processing based on two-pulse correlation. Electronics Letters, 37(4), 234. doi:10.1049/el:20010178Gordon, R. E., & Chen, L. R. (2006). Demonstration of all-photonic spectral label-switching for optical MPLS networks. IEEE Photonics Technology Letters, 18(4), 586-588. doi:10.1109/lpt.2006.870188Habib, C., Baby, V., Chen, L. R., Delisle-Simard, A., & LaRochelle, S. (2008). All-Optical Swapping of Spectral Amplitude Code Labels Using Nonlinear Media and Semiconductor Fiber Ring Lasers. IEEE Journal of Selected Topics in Quantum Electronics, 14(3), 879-888. doi:10.1109/jstqe.2008.918047Cole, C., Huebner, B., & Johnson, J. (2009). Photonic integration for high-volume, low-cost applications. IEEE Communications Magazine, 47(3), S16-S22. doi:10.1109/mcom.2009.4804385Calabretta, N., Jung, H.-D., Llorente, J. H., Tangdiongga, E., Koonen, T. A. M. J., & Dorren, H. J. S. (2009). All-Optical Label Swapping of Scalable In-Band Address Labels and 160-Gb/s Data Packets. Journal of Lightwave Technology, 27(3), 214-223. doi:10.1109/jlt.2008.2009319Smit, M. K., & Van Dam, C. (1996). PHASAR-based WDM-devices: Principles, design and applications. IEEE Journal of Selected Topics in Quantum Electronics, 2(2), 236-250. doi:10.1109/2944.577370Eisenstein, G. (1989). Semiconductor optical amplifiers. IEEE Circuits and Devices Magazine, 5(4), 25-30. doi:10.1109/101.29899Munoz, P., Pastor, D., & Capmany, J. (2002). Modeling and design of arrayed waveguide gratings. Journal of Lightwave Technology, 20(4), 661-674. doi:10.1109/50.996587Soldano, L. B., & Pennings, E. C. M. (1995). Optical multi-mode interference devices based on self-imaging: principles and applications. Journal of Lightwave Technology, 13(4), 615-627. doi:10.1109/50.372474Zilkie, A. J., Meier, J., Mojahedi, M., Poole, P. J., Barrios, P., Poitras, D., … Aitchison, J. S. (2007). Carrier Dynamics of Quantum-Dot, Quantum-Dash, and Quantum-Well Semiconductor Optical Amplifiers Operating at 1.55 μm\mu{\hbox {m}}. IEEE Journal of Quantum Electronics, 43(11), 982-991. doi:10.1109/jqe.2007.90447

    “Tourism, water, and gender”—An international review of an unexplored nexus

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    This international literature review of the tourism–water nexus identifies a gender gap. Tourism development can affect water supply both quantitatively and qualitatively. Many regions will face considerable problems of water availability and quality, affecting their tourism sector and increasing competition with local residents, and other industries especially agriculture. This international review of literature explores the tourism–water nexus, comparing and contrasting literature published in English, Chinese, and Spanish. Securing access to safe water for continued tourism development is a common theme and the vast majority of work has focused on hotels including water pricing, water-saving practices and innovative management methods. In all continents, struggles are apparent, and the unsustainability of tourism is having impacts on water quantity and quality. This article identifies significant gaps in the literature including climate change, the energy-water nexus, and the links with the Sustainable Development Goals. Furthermore, studies from a gendered perspective are minimal and the potential for areas of further gendered studies within the tourism–water nexus are highlighted including intersectionality, water insecurity and sanitation, tourism and gender based violence, and additional unpaid care work

    Cribado de la depresión mayor en la infancia y adolescencia (Parte 2)

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    El síndrome depresivo que aparece durante la infancia o la adolescencia tiende a seguir un curso crónico, con alta probabilidad de permanecer en la edad adulta. Su sintomatología repercute en la vida diaria del menor y, en el caso de la depresión mayor, supone un riesgo para la aparición de conducta suicida. Dada la variabilidad de sus manifestaciones clínicas y las dificultades en el diagnóstico, se plantea la posible utilidad del uso de cuestionarios de cribado en la población infantil y adolescente, a partir de un análisis del rendimiento de estos y de la eficacia de las medidas terapéuticas actuales. El presente trabajo se ha dividido en dos partes, y al final de este se recopilan las recomendaciones de distintos grupos de trabajo y tras el análisis de la evidencia, las recomendaciones que el grupo PrevInfad ha consensuado para la consulta de los pediatras en Atención Primaria

    Female Institutional Directors on Boards and Firm Value

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    The aim of this research is to examine what impact female institutional directors on boards have on corporate performance. Previous research shows that institutional female directors cannot be considered as a homogeneous group since they represent investors who may or may not maintain business relations with the companies on whose corporate boards they sit. Thus, it is not only the effect of female institutional directors as a whole on firm value that has been analysed, but also the impact of pressure-resistant female directors, who represent institutional investors (investment, pension and mutual funds) that only invest in the company, and do not maintain a business relation with the firm. We hypothesize that there is a non-linear association, specifically quadratic, between institutional and pressure-resistant female directors on boards and corporate performance. Our results report that female institutional directors on boards enhance corporate performance, but when they reach a certain threshold on boards (11.72 %), firm value decreases. In line with female institutional directors, pressure-resistant female directors on boards also increase firm value, but only up to a certain figure (12.71 % on boards), above which they have a negative impact on firm performance. These findings are consistent with an inverted U-shaped relationship between female institutional directors and pressure-resistant female directors and firm performance

    Definition of a temporal distribution index for high temporal resolution precipitation data over Peninsular Spain and the Balearic Islands: the fractal dimension; and its synoptic implications

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    Precipitation on the Spanish mainland and in the Balearic archipelago exhibits a high degree of spatial and temporal variability, regardless of the temporal resolution of the data considered. The fractal dimension indicates the property of self-similarity, and in the case of this study, wherein it is applied to the temporal behaviour of rainfall at a fine (10-min) resolution from a total of 48 observatories, it provides insights into its more or less convective nature. The methodology of Jenkinson & Collison which automatically classifies synoptic situations at the surface, as well as an adaptation of this methodology at 500 hPa, was applied in order to gain insights into the synoptic implications of extreme values of the fractal dimension. The highest fractal dimension values in the study area were observed in places with precipitation that has a more random behaviour over time with generally high totals. Four different regions in which the atmospheric mechanisms giving rise to precipitation at the surface differ from the corresponding above-ground mechanisms have been identified in the study area based on the fractal dimension. In the north of the Iberian Peninsula, high fractal dimension values are linked to a lower frequency of anticyclonic situations, whereas the opposite occurs in the central region. In the Mediterranean, higher fractal dimension values are associated with a higher frequency of the anticyclonic type and a lower frequency of the advective type from the east. In the south, lower fractal dimension values indicate higher frequency with respect to the anticyclonic type from the east and lower frequency with respect to the cyclonic type

    Letter of intent for KM3NeT 2.0

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    Letter of intent for KM3NeT 2.0

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    The main objectives of the KM3NeT Collaboration are ( i ) the discovery and subsequent observation of high-energy neutrino sources in the Universe and ( ii ) the determination of the mass hierarchy of neutrinos. These objectives are strongly motivated by two recent important discoveries, namely: ( 1 ) the high- energy astrophysical neutrino signal reported by IceCube and ( 2 ) the sizable contribution of electron neutrinos to the third neutrino mass eigenstate as reported by Daya Bay, Reno and others. To meet these objectives, the KM3NeT Collaboration plans to build a new Research Infrastructure con- sisting of a network of deep-sea neutrino telescopes in the Mediterranean Sea. A phased and distributed implementation is pursued which maximises the access to regional funds, the availability of human resources and the syner- gistic opportunities for the Earth and sea sciences community. Three suitable deep-sea sites are selected, namely off-shore Toulon ( France ) , Capo Passero ( Sicily, Italy ) and Pylos ( Peloponnese, Greece ) . The infrastructure will consist of three so-called building blocks. A building block comprises 115 strings, each string comprises 18 optical modules and each optical module comprises 31 photo-multiplier tubes. Each building block thus constitutes a three- dimensional array of photo sensors that can be used to detect the Cherenkov light produced by relativistic particles emerging from neutrino interactions. Two building blocks will be sparsely con fi gured to fully explore the IceCube signal with similar instrumented volume, different methodology, improved resolution and complementary fi eld of view, including the galactic plane. One building block will be densely con fi gured to precisely measure atmospheric neutrino oscillations. Original content from this work may be used under the ter
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