2,759 research outputs found

    Transitions into permanent employment in Spain : an empirical analysis for young workers

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    We analyze the Spanish temporary workers’ transitions into permanent employment and to what extent those who become unemployed are able to achieve a permanent job. Our focus is placed on the role of the individual’s sequence of temporary contracts on the probability of moving from temporary into permanent employment. We apply multiplespell duration techniques to a longitudinal dataset of temporary workers obtained from Social Security records for the period 1996-2003. We basically find that even though transitions into permanent employment increase with tenure, temporary jobs do not constitute stepping stones towards permanent employment, since the probability of obtaining a permanent job decreases with repeated temporary jobs. Results also show that individuals with high duration of unemployment flow into permanent work less frequently.

    A 300 GHz "Always-in-Focus" Focusing System for Target Detection

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    A focusing system for a 300 GHz radar with 5 m target distance and 10 mm diameter spot size resolution is proposed. The focusing system is based on a Gaussian telescope scheme and its main parameters have been deÂŹsigned using Gaussian beam quasi-optical propagation theory with an in-house developed MATLABÂź based analysis tool. Then, this approach has been applied to a real focusing system based on two elliptical mirrors in order to reduce the distortion and cross-polar level and a plane mirror to provide scanning capabilities. The overÂŹall system has been simulated with a full-wave electromagÂŹnetic simulator and its behavior is presented. With this approach, the focusing system always works "in-focus" since the only mirror that is rotated when scanning is the output plane mirror, so the beam is almost not distorted. The design process, although based in the well-known Gaussian beam quasi-optical propagation theory, provides a fast and accurate method and minimizes the overall size of the mirrors. As a consequence, the size of the focusing system is also reduced

    Inferencia del origen del bovino Criollo Cubano a través del anålisis de patri- y matrilinajes

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    Antes de descubrimiento, no existĂ­an bovinos en AmĂ©rica. Los primeros, fueron introducidos en la Antillas Mayores (La Española, Puerto Rico, Jamaica y Cuba), y desde allĂ­ trasladados al resto de LatinoamĂ©rica. Actualmente, existen en Cuba alrededor de 1300 bovinos Criollos, concentrados principalmente en la regiĂłn oriental. Con el objetivo de analizar el origen materno de esta raza y detectar eventos contemporĂĄneos de flujo gĂ©nico por vĂ­a paterna, se analizĂł un fragmento de 240 pb del D-loop mitocondrial (mtADN) y 5 microsatĂ©lites del cromosoma Y (BTY), en 36 hembras y 21 machos respectivamente. La diversidad genĂ©tica se estimĂł mediante el nĂșmero de haplotipos, el nĂșmero de sitios polimĂłrficos, el nĂșmero de diferencias nucleotĂ­dicas entre pares de secuencias y el Ă­ndice de diversidad nucleotĂ­dica, mientras que el anĂĄlisis filogenĂ©tico se realizĂł utilizando el mĂ©todo de median joining network. Dicho anĂĄlisis permitiĂł detectar 15 haplotipos mitocondriales (10 del haplogrupo europeo T3, 3 del africano T1, 1 del cercano oriente T2 y 1 ambiguo T1-T3) y 3 haplotipos en el BTY, ambos del haplogrupo cebuĂ­no Y3. En el mtADN se detectaron 23 sitios polimĂłrficos con una diversidad nucleotĂ­dica de 0,014 y 3,36 diferencias medias entre pares de secuencias. En conclusiĂłn, la poblaciĂłn de bovinos Criollos Cubanos presentĂł una composiciĂłn haplotĂ­pica mitocondrial comparable a la de otras razas criollas y mediterrĂĄneas, hecho que concuerda con su origen histĂłrico. El BTY evidenciĂł altos niveles de introgresion paterna de genes del zebĂș.Cattle was absent from America before the discovery. Initially, bovine were brought to Greater Antilles (La Española, Puerto Rico, Jamaica and Cuba islands), and in the course of a few years, they were taken from Caribbean islands to the rest of Latin America. Nowadays, Cuban Creole cattle population is about 1300 heads, mainly located in the eastern region of the island. With the aim of analyzing the maternal origin of Cuban Creole cattle and detect possible contemporaneous, male mediated, gene flow, a 240 pb fragment of mitochondrial D-loop (mtDNA) and five microsatellites of Y chromosome (BTY) were studied in 36 dams and 21 sires, respectively. Genetic diversity was evaluated through number of haplotypes, mean number of pairwise differences and nucleotide diversity. The phylogenetic analysis was performed using a median joining. A total of 15 mtDNA haplotypes were detected in the studied population (10 from the European haplogroup T3, 3 from the African T1, 1 from the Nearern East T2, and 1 ambiguous T1-T3). The number of polymorphic sites, the mean nucleotide diversity, and the mean number of pairwise differences were 23, 0.014 and 3.36, respectively. Two patrilinages were detected, both belonging to the Y3 Zebu haplogroup. In conclusion, Cuban Creole cattle population had a mtDNA haplotypic composition similar to the observed in Creole and Mediterranean breeds, what is in concordance with its historical origin. Y chromosome analysis evidenced a male mediated process of zebu introgression.Fil: Liron, Juan Pedro. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; ArgentinaFil: Acosta, A.. Centro Nacional de Sanidad Agropecuaria. Laboratorio de GenĂ©tica Molecular; CubaFil: Rogberg Muñoz, Andres. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; ArgentinaFil: Uffo, O.. Centro Nacional de Sanidad Agropecuaria. Laboratorio de GenĂ©tica Molecular; CubaFil: Posik, Diego Manuel. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; ArgentinaFil: Garcia, J.. Ministerio de la Agricultura. DirecciĂłn Nacional de GenĂ©tica; CubaFil: Peral Garcia, Pilar. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; ArgentinaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CONICET- La Plata. Instituto de GenĂ©tica Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de GenĂ©tica Veterinaria; Argentin

    Transfer learning or design a custom CNN for tactile object recognition

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    International Workshop on Robotac: New Progress in Tactile Perception and Learning in RoboticsNovel tactile sensors allow treating pressure lectures as standard images due to its highresolution. Therefore, computer vision algorithms such as Convolutional Neural Networks (CNNs) can be used to identify objects in contact. In this work, a high-resolution tactile sensor has been attached to a robotic end-effector to identify objects in contact. Moreover, two CNNs-based approaches have been tested in an experiment of classification of pressure images. These methods include a transfer learning approach using a pre-trained CNN on an RGB images dataset and a custom-made CNN trained from scratch with tactile information. A comparative study of performance between them has been carried out.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂ­a Tech. Spanish project DPI2015-65186-R, the European Commission under grant agreement BES-2016-078237, the educational project PIE-118 of the University of Malag

    Laser performance of Coumarin 540A dye molecules in polymeric host media with different viscosities: From liquid solution to solid polymer matrix

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    11 pages, 12 figures, 3 tables.-- PACS: 42.70.Hj; 42.55.Rz; 42.55.Mv; 66.20.+d; 78.55.Bq; 78.55.KzPhotophysical parameters and lasing properties of Coumarin 540A dye molecules are studied in solutions of increasing viscosity, from liquid solutions in 1,4-dioxane to solid solutions in poly(methyl methacrylate). The fluorescence quantum yield and lasing efficiencies decrease as the viscosity of the solution increases, reflecting the strong influence of the rigidity of the medium on the radiative processes. The photodegradation mechanisms acting on the fluorophores are analyzed by following the dependence of laser induced fluorescence and laser output on the number of pump laser pulses. The fluorescence redistribution after pattern photobleaching technique is used, and Fick's second law is applied to study the diffusion of dye molecules in the highly viscous polymer solutions. The diffusion coefficients of the dye molecules as a function of the increased viscosity of the medium are determined.This work was supported by the Spanish CICYT Project MAT94-0757.Peer reviewe

    Validación con datos in-situ de alturas de ola obtenidas mediante radar altimétrico

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    Los rĂĄdares altimĂ©tricos a bordo de satĂ©lites artificiales, han sido diseñados para dar informaciĂłn precisa de la altura del nivel del mar, la altura de ola significante y la velocidad del viento sobre la superficie del mar. En los estudios, tanto anteriores como actuales, se observan problemas en las regiones costeras, donde las medidas del altĂ­metro tienen menor precisiĂłn y una mayor dificultad a la hora de interpretar estos datos. Estos inconvenientes son debidos a dos factores principales. En primer lugar, la contaminaciĂłn de la señal radar debido a la cercanĂ­a de la costa. En segundo lugar, inexactitudes en las correcciones de marea y troposfĂ©rica hĂșmeda. A estos problemas se añade la complejidad de la zona de estudio, al ser una regiĂłn con una amplia gama de procesos hidrodinĂĄmicos con diversas escalas espacio-temporales. Tener acceso a informaciĂłn exacta en la costa, con las condiciones que conlleva, tiene una gran importancia debido al enorme interĂ©s econĂłmico-estratĂ©gico de la zona litoral. Este interĂ©s hace que surjan nuevas estrategias para generar productos altimĂ©tricos optimizados para tales condiciones. Las medidas de la altura de ola significante y su variabilidad en las ĂĄreas costeras son usadas para muchos propĂłsitos (por ejemplo, anĂĄlisis del transporte de sedimento, setup de la ola y tormentas de marea), y para la validaciĂłn/calibraciĂłn de modelos (pronĂłstico de oleaje, circulaciĂłn oceĂĄnica). Estas aplicaciones sirven para un amplio rango de propĂłsitos sociales relevantes, tales como el diseño de estructuras de ingenierĂ­a en alta mar, la protecciĂłn de las zonas costeras, rutas para los buques y la planificaciĂłn de las operaciones en el ocĂ©ano. Muchos estudios se han dedicado a la validaciĂłn de los datos de la altura de ola significante dados por el radar altimĂ©trico a bordo de satĂ©lites artificiales, utilizando observaciones in-situ. El objetivo de esta ponencia es exponer una metodologĂ­a para validar los datos de altura de oleaje proporcionados por el radar altimĂ©trico RA-2 a bordo del satĂ©lite ENVISAT, a partir de datos in-situ medidos por una boya, y su aplicaciĂłn a un caso particular

    Application of intensified Fenton oxidation to the treatment of hospital wastewater: Kinetics, ecotoxicity and disinfection

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    Fenton oxidation has proved to be effective for the treatment of a real hospital wastewater. The intensification of the process viz. the improvement on the efficiency of H2O2consumption, by increasing the temperature, is necessary to operate in a single step and avoid high reaction times and the need of large H2O2 and iron concentrations. This approach would allow taking advantage of the heat energy contained in the laundry stream since the washing process is performed at high temperature to assure disinfectionof the hospital textiles. In this work, temperatures within the range of 50-90 °C have been tested, which allowed an effective oxidation of the real wastewater ([COD]0 = 365 mg L-1, [Phenols]0 = 8.4 mg L-1, [total coliforms]0 = 4.16 × 106 MPN/100 mL, 5 toxicity units) with the stoichiometric amount of H2O2 (1000 mg L-1) and a relatively low iron concentration (25 mg L-1 Fe3+). Operating at 90 °C, complete disappearance of phenolic compounds and 70% and 50% reduction of COD and TOC were achieved in 1 h reaction time. Time evolution of those global parameters were appropriately fitted to pseudo-first and second order kinetic equations, providing a useful approach for design purposes. The main by-products were short-chain organic acids (oxalic and formic), being the final effluents non-toxic. Disinfection of the hospital wastewater was also achieved at all the operating temperatures tested, as confirmed by the absence of coliformsThis research has been supported by the CM through the project S2013/MAE-2716 and by the Spanish MINECO through the project CTQ2013-41963-R. M. Munoz thanks the Spanish MINECO for a Juan de la Cierva-Incorporación postdoctoral contract (IJCI-2014-19427
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