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Search Results: 1 - 10 of 462049 matches for " A. Lorente "
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Effect of Parameters on Geoa/Geob/1 Queues: Theoretical Analysis and Simulation Results  [PDF]
A. Lorente, M. S. Sánchez
Applied Mathematics (AM) , 2018, DOI: 10.4236/am.2018.92011
Abstract:
This paper analyzes a discrete-time Geoa/Geob/1 queuing system with batch arrivals of fixed size a, and batch services of fixed size b. Both arrivals and services occur randomly following a geometric distribution. The steady-state queue length distribution is obtained as the solution of a system of difference equations. Necessary and sufficient conditions are given for the system to be stationary. Besides, the uniqueness of the root of the characteristic polynomial in the interval (0, 1) is proven which is the only root needed for the computation of the theoretical solution with the proposed procedure. The theoretical results are compared with the ones observed in some simulations of the queuing system under different sets of parameters. The agreement of the results encourages the use of simulation for more complex systems. Finally, we explore the effect of parameters on the mean length of the queue as well as on the mean waiting time.
Rese a de "Educar por competencias, qué hay de nuevo?" de Gimeno Sacristán, J. (Comp.)
Rocío Lorente García
PROFESORADO , 2008,
Abstract:
Configuración de las políticas europeas de formación profesional ante las nuevas demandas del mercado laboral
Rocío Lorente García
PROFESORADO , 2011,
Abstract: La educación y, especialmente, la formación profesional no pueden quedar ajenas a las transformaciones de la estructura social y económica, y deben prestar especial atención a los cambios resultantes de los procesos de globalización y desarrollo de nuevas tecnologías de la información y la comunicación que suponen una nueva reestructuración del trabajo y que, en consecuencia, requieren repensar la formación y preparación de los trabajadores. Ante este panorama, los sistemas europeos de educación y formación están, en la actualidad, inmersos en un proceso de reformas para poder responder a los retos planteados en la Cumbre de Lisboa ante el comienzo del siglo para conseguir que la Unión Europea se convierta en la sociedad del conocimiento más competitiva del mundo. Así, se plantea la necesidad de que las reformas nacionales sigan una misma dirección para la consecución de unos objetivos comunes, dise ando para ello el Método Abierto de Coordinación (MAC). Un concepto clave de la actual política educativa europea es el de "la educación a lo largo de la vida", que se convertirá en el protagonista en el discurso político referido a la educación y formación en la Unión Europea. Otro concepto que impregnará la política educativa europea será el de "competencias profesionales". Al extender la noción de educación a lo largo de toda la vida y hacer hincapié en las competencias profesionales, es posible facilitar el acceso a la educación y elevar el nivel de ésta (objetivo de las políticas educativas de la Unión Europea). En este artículo, reflexionamos sobre las implicaciones que todo esto tiene sobre las ense anzas profesionales que, se reconfiguran siguiendo estas directrices.
Roadmap for double hypernuclei spectroscopy at PANDA
Pochodzalla J.,Sanchez Lorente A.
EPJ Web of Conferences , 2010, DOI: 10.1051/epjconf/20100307008
Abstract: Hypernuclear Physics is currently attracting renewed attention. Thanks to the use of stored $ar{p}$ beams, copious production of double Λ hypernuclei is expected at the $ar{P}$anda experiment which will enable high precision γ–spectroscopy of such nuclei for the rst time. In the present work we have studied the population of particle stable, excited states in double hypernuclei after the capture of a Ξ within a statistical decay model. In order to check the feasibility of producing and performing γ–spectroscopy of double hypernuclei at $ar{P}$ANDA, an event generator based on these calculations has been implemented in the $ar{P}$ANDA simulation framework PANDAROOT.
Size effects in surface reconstructed $<100>$ and $< 110>$ silicon nanowires
R. Rurali,A. Poissier,N. Lorente
Physics , 2006, DOI: 10.1103/PhysRevB.74.165324
Abstract: The geometrical and electronic structure properties of $<100>$ and $<110>$ silicon nanowires in the absence of surface passivation are studied by means of density-functional calculations. As we have shown in a recent publication [R. Rurali and N. Lorente, Phys. Rev. Lett. {\bf 94}, 026805 (2005)] the reconstruction of facets can give rise to surface metallic states. In this work, we analyze the dependence of geometric and electronic structure features on the size of the wire and on the growth direction.
Creating pseudo Kondo-resonances by field-induced diffusion of atomic hydrogen
Werner A Hofer,Gilberto Teobaldi,Nicolas Lorente
Physics , 2007, DOI: 10.1088/0957-4484/19/30/305701
Abstract: In low temperature scanning tunneling microscopy (STM) experiments a cerium adatom on Ag(100) possesses two discrete states with significantly different apparent heights. These atomic switches also exhibit a Kondo-like feature in spectroscopy experiments. By extensive theoretical simulations we find that this behavior is due to diffusion of hydrogen from the surface onto the Ce adatom in the presence of the STM tip field. The cerium adatom possesses vibrational modes of very low energy (3-4meV) and very high efficiency (> 20%), which are due to the large changes of Ce-states in the presence of hydrogen. The atomic vibrations lead to a Kondo-like feature at very low bias voltages. We predict that the same low-frequency/high-efficiency modes can also be observed at lanthanum adatoms.
On new rational approximants to ζ(3)
J. Arvesú,A. Soria-Lorente
Mathematics , 2012,
Abstract: New (infinitely many) rational approximants to \zeta(3) proving its irrationality are given. The recurrence relations for the numerator and denominator of these approximants as well as their continued fraction expansions are obtained. A comparison of our approximants with Ap\'ery's approximants to \zeta(3) is shown.
First order non-homogeneous q-difference equation for Stieltjes function characterizing q-orthogonal polynomials
J. Arvesú,A. Soria-Lorente
Statistics , 2012,
Abstract: In this paper we give a characterization of some classical q-orthogonal polynomials in terms of a difference property of the associated Stieltjes function, i.e this function solves a first order non-homogeneous q-difference equation. The solutions of the aforementioned q-difference equation (given in terms of hypergeometric series) for some canonical cases, namely, q-Charlier, q-Kravchuk, q-Meixner and q-Hahn are worked out.
Neumonitis por hipersensibilidad (alveolitis alérgica extrínseca) Hypersensitivity Pneumonitis (extrinsic allergic alveolitis)
P. Cebollero,S. Echechipía,A. Echegoyen,M. P. Lorente
Anales del Sistema Sanitario de Navarra , 2005,
Abstract: El pulmón del granjero se describió por primera vez en 1932. Podemos definir la neumonitis por hipersensibilidad como una enfermedad pulmonar y sistémica que cursa con disnea y tos, y que se produce por la inflamación de tipo inmunológico de las paredes alveolares y vías aéreas terminales y que es secundaria a la inhalación repetida de una variedad de antígenos por un huésped susceptible. Puede decirse que es una enfermedad infradiagnosticada y sólo un alto grado de sospecha clínica y una historia detallada de la exposición pueden llevar a un diagnóstico precoz y un tratamiento satisfactorio. Una combinación entre los hallazgos clínico-radiológicos, funcionales, citológicos o anatonomopatológicos, en algunos casos, nos llevarán al diagnóstico. El tratamiento se funda en la evitación del agente causal y, en los casos más graves, la administración de tratamiento corticoideo sistémico. Farmer’s lung was first described in 1932. We can define hypersensitivity pneumonitis as a pulmonary and systemic disease that is accompanied by dyspnoea and coughing; it is caused by an immunological type of inflammation of the alveolar walls and the terminal airways and it is secondary to the repeated inhalation of a variety of antigens by a susceptible host. It can be said that it is an underdiagnosed disease and only a high degree of clinical manifestations and a detailed history of exposure can lead to an early diagnosis and satisfactory treatment. A combination among clinical-radiological, functional, cytological or pathological findings leads in some cases to a diagnosis. Treatment is based on avoiding further exposure to the causal agent and in the more serious cases the administration of systemic corticoid treatment.
Viral kinetics during the first month of treatment in patients with genotype 1 chronic hepatitis C Cinética viral durante el primer mes de tratamiento en pacientes con hepatitis crónica C genotipo 1
A. Hernández,F. Domper,A. León,R. Lorente
Revista Espa?ola de Enfermedades Digestivas , 2009,
Abstract: Objective: to identify predictive factors of response to pegylated interferon alpha-2b and ribavirin in patients with genotype 1 chronic hepatitis C. Viral kinetics were studied in weeks 2 and 4. Methods: a prospective and consecutive study of patients with genotype 1 chronic hepatitis C referred to our Hepatology Clinic between January 2004 and October 2006 for antiviral treatment. Baseline data were recorded and viremia levels were determined hours before the weekly dose of pegylated interferon by qualitative and quantitative PCR. Results: 57 patients were included in the study, although 3 of these were excluded during follow up; 65% were male (n = 35), with a mean age of 42 (26-65) years. Baseline viremia levels were > 800,000 IU/mL in 67% (n = 36). Liver biopsy was performed in 86% (n = 46), 22% (n = 12) had advanced fibrosis. Forty were na ve, 4 relapsing and 10 non-responders. Ribavirin dose was modified in one patient alone due to adverse effects. End treatment response and sustained virological response (SVR) were 59 and 41%, respectively. A univariate analysis revealed a statistically significant association of SVR with baseline viremia (p = 0.006), baseline GGT (p = 0.025), and a reduction in viremia ≥ 2 logs at 2, 4 and 12 weeks (p = 0.001). The extent of viremia reduction at week 2 was associated with 100% SVR, and at 4 weeks the positive predictive values was 84% and the negative predictive values was 96.5%. A subanalysis of the na ve group yielded analogous results. Conclusions: in our study, a reduction in viremia ≥ 2 logs 2 weeks after treatment could ensure SVR. At 4 weeks, most non-responders could be identified. Objetivo: identificar qué factores predicen la respuesta al interferón pegilado alfa-2b y ribavirina en pacientes con hepatitis crónica C genotipo 1. Se estudió la cinética viral en la semana 2 y 4. Métodos: se evaluaron de forma prospectiva y consecutiva a los pacientes con hepatitis crónica C genotipo 1 remitidos a nuestra consulta de hepatología entre enero de 2004 y octubre de 2006, para tratamiento antiviral. Se recogieron datos basales y la viremia se determinó horas antes de la dosis semanal de interferón pegilado por PCR cualitativa y cuantitativa. Resultados: cincuenta y siete pacientes fueron incluidos aunque 3 fueron excluidos durante el seguimiento. Un 65% fueron varones (n = 35) con edad media de 42 (26-65) a os. La viremia basal fue > 800.000 UI/ml en 67% (n = 36). Se realizó biopsia hepática en 86% (n = 46), 22% (n = 12) tenían fibrosis avanzada. 40 fueron na ves, 4 recidivantes y 10 no respondedores. La dosis d
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