revista de física mexicana

Any impact factor or scientometric indicator alone will not give you the full picture of a science journal. (Learn More), The h-index is an author-level metric that attempts to measure both Responsable: Prensa Científica, S.A. Finalidad: enviarle por correo electrónico los boletines que haya solicitado recibir.Derechos: tiene derecho a acceder, rectificar y suprimir sus datos, así como a otros derechos, como se explica en la información adicional y detallada que puede consultar en nuestra . The installed neutron irradiation cell at the USB-Laboratory is employed frequently for applications where the neutron field should be monitored. Reservas de Derechos al Uso Exclusivo No. Bi-monthly publication. A heterocyclic compound 5-acetyl-2,4-dimethylthiazole, spectroscopic, natural bond orbital, nonlinear optical and molecular docking studies. Revista Mexicana de Política Exterior número 123, es una publicación cuatrimestral de la Secretaría de Relaciones Exteriores por medio del Instituto Matías Romero, República de El Salvador núm. - Verificando disponibilidad . The track density reveals the boron density spatial distribution. G. Lara-Hernandez, Revista Mexicana de sociología CD 301/R lC H8/R Revista Mexicana de sociología / ed. 5. Neste sentido, o objectivo deste estudo era adaptar e validar o CIPEF (Cuestionario de Influencia en la Planificación en la Educación Física) ao contexto mexicano. D.V. Journal of Radioanalytical and Nuclear Chemistry. Límite de responsabilidad / Descargo de responsabilidad de la garantía: Si bien el editor/es y los autores y autoras han realizado un esfuerzo para preparar este libro, no hacen declaraciones ni garantías con respecto a la exactitud o integridad del contenido de este libro y . DE BARCELONA A LA BRETAÑA FRANCESA. 70-348 , México, Distrito Federal, MX, 04510, (52-55)5622-4946. ISO 4 (Information and documentation - Rules for the abbreviation of title words and titles of publications) is an international standard, defining a uniform system for the abbreviation of serial publication titles. Revista con exportación de datos en desde Redalyc, Investigations of the spin hamiltonian parameters and local structure for Cr3+inK2PdCl4 single crystal. The Pb-target (diameter 8.4 cm, length 45.6 cm) is surrounded by a natU-blanket (206.4 kg) and used for transmutation studies of hermetically sealed radioactive samples of 129I, 237Np, 238Pu and 239Pu. Lateral distribution of the 10B isotope within a boron carbide film of 550 nm maximum thickness deposited on silicon wafer using pulsed laser deposition technique has been determined taking advantage of the high cross section for (n,α) reaction and nuclear tracks detectors (NTD – LR-115 Kodak Pathé). I, Entropía de discos rígidos auto-impulsados como parámetro de orden para peatones en contraflujo. 欢迎内容投稿、网站推荐或举报！联系邮箱：ikx#ikx.cn（#修改为@）, scielo.unam.mx/scielo.php/script_sci_serial/pid_0035-001X/lng_en/nrm_iso. Leave this field blank . Academia.edu no longer supports Internet Explorer. Keywords: LR-115 detector;... Journal of Radioanalytical and Nuclear Chemistry. Revista Mexicana de Investigación Educativa Revista Educarnos Revista Electrónica de Investigación Educativa. Username or e-mail * Password * Forgot Password. Investigaciones Educativas Hispano-Mexicanas. Publicación bimestral. most cited papers and the number of citations that they have received Abstract: A model of irreversible Carnot-like power plant with n Carnot-like cycles is optimized. Academic field: . Istmo Revista virtual de estudios literarios y culturales centroamericanos Panamá . 5. Instrucciones para autores ; Envío de artículos; medigraphic.com . 《revista mexicana de fisica》发布于爱科学网，并永久归类相关sci期刊导航类别中，本站只是硬性分析 "《rev mex fis》" 杂志的可信度。学术期刊真正的价值在于它是否能为科技进步及社会发展带来积极促进作用。 Número actual. Abstract: We present a model of a charged membrane where the charge density is distributed in a region of thickness d m . J.J.A. Original research or instrumental papers which require fast publication. 62 (2016) 362-368], Criterios Altamente Valorados / Criterios Deseables, Criterios Altamente Valorados Cuantitativos, {{criterio.prioridadCriterio}}. Has supplement: Suplemento de la revista mexicana de física, 2683-2585. Cartas. You can download the paper by clicking the button above. A quién se dirige? M.E. The maximum length for a letter is seven pages. Hui-Ning Dong. Revisión. S.M. *La presidenta municipal Lili Campos continuará impulsando en este 2023, la activación física en beneficio de las familias solidarenses con la biciruta Playa del Carmen, Solidaridad a 08 de enero.- Cartas. Revista Ciencia es el órgano oficial de la Academia Mexicana de Ciencias. Individual pedestrians are modeled as self- propelled hard disks with local evasive interactions. Haydn Barros Rosemerie Alvarado. Los peatones individuales se modelan como discos r ́ ıgidos auto-impulsados con interacciones locales de evasi ́ on. Revista Mexicana de Fisioterapia Trimestral IssN: 0188-2503 Publicación trimestral del Instituto de Investigaciones sociales de la Universidad . Medigraphic. Revista Mexicana de Medicina Física y Rehabilitación; Revista Argentina de Rehabilitación; Para terminar, te interesa saber un par de detalles más. M.A. Entre los episodios del proceso de Conquista que serán rememorados este 2020, se encuentra la llamada "Noche triste", del cual existe un testimonio ma. This experimental setup provide us with an intense neutron beam with a white spectrum from thermal to 1 GeV and with an outstanding high resolution provided. Demirkol. Academic field: . Valora este material: 5.0. The 1-dimensional confined harmonic oscillator revisited, Abstract: We study the size effect on the energy levels of the 1 –dimensional harmonic oscillator confined within a box of with impenetrable walls and large L . Abstract: In this work the study of the structural, morphologic characteristics, optical and electrical properties of the thin films of ZnO in temperatures and annealing atmospheres different was realized. 值还取决于各种因素的综合分析。, 此文由爱科学编辑！：首页 > SCI期刊 > ç‰©ç† » REVISTA MEXICANA DE FISICA, Copyright © 2015-至今   爱科学 iikx.com All Rights Reserved. The advantages of the technique are discussed. The passive device is a Kodak-Path`e LR-115 externally coated with a thin (0,1mm) binary glass metal strip Fe75B25 where the 10B(n,®)7Li reaction converts free neutrons into alpha particles that are registered as etched tracks. A radioisotope neutron source (252Cf, 20 μg) and a 60 × 60 × 80 cm3 graphite cube as moderator produce a relatively uniform thermal neutron field. Revista Mexicana de Física. The Pb-target (diameter 8.4 cm, length 45.6 cm) is surrounded by a natU-blanket (206.4 kg) and used for transmutation studies of hermetically sealed radioactive samples of 129I, 237Np, 238Pu and 239Pu. Abstract: A model to describe the interaction between a spherical permanent magnet and a square superconductor in the mixed state was elaborated. ¡Gracias por este primer año! Revista Mexicana de Mastología: Mastología: Revista Mexicana de Medicina Familiar: Medicina de familia, medicina comunitaria, atención primaria de salud: Revista Mexicana de Medicina Física y Rehabilitación: Discapacidad, rehabilitación, fisioterapia, terapia ocupacional: Revista Mexicana de Medicina Forense y Ciencias de la Salud Li-Na Wu, Translate PDF. SCImago Journal Rank (SJR indicator) is a measure of scientific influence En Revista TURISMO, Medio de Información y Promoción Turística Fundado en 1978, nos dedicamos a promover los lugares más extraordinarios de México y el Mundo. The correspondent flat or curved (de Sitter or hyperbolic) dilatonic two branes are created, as a rule, thanks to quantum . Como parte de los procesos para reacreditar la Licenciatura en Educación Física, la Facultad de Ciencias de la Cultura Física de la UACH recibió el 12 y 13 de diciembre al Comité Evaluador del Consejo Mexicano para la Reacreditación de la Enseñanza de la Cultura de la Actividad Física A.C. (Comacaf) Es importante . CdS nanoparticles were first synthesized using chemical precipitation. Terra Revista de la Sociedad Mexicana de la Ciencia del Suelo Nicaragua . You can download the paper by clicking the button above. Abstract: We present a theorical study of the kinetic orientational relaxation of a colloidal monodispersed system of stiff and long rods, for small wavevectors. [ Revista mexicana de medicina física y rehabilitación, México, 2005 Vol. Aniversario de la Sociedad Mexicana de Física70th anniversary of the Mexican Physical Society Previous Next NOTICIAS SMF NEWS CONVOCATORIAS Y EVENTOS CALLS AND EVENTS MIEMBROS SMF MEMBERSHIP PROGRAMAS PERMANENTES PERMANENT PROGRAMS CONGRESO CONGRESS PUBLICACIONES PUBLICATIONS OLIMPIADAS OLYMPICS DIVULGACIÓN OUTREACH ENSEÑANZA EDUCATION Aparatos y Experimentos de Física PHYSICS DEVICES AND . Mex. 04-2021-071613424100-102 otorgado por el instituto nacional del derecho de autor. Abstract: The spin Hamiltonian parameters (SHPs) (g factors and zero-field splittings (ZFSs) D and E) and the local structure for Cr 3+ in K 2 PdCl 4 single crystal are theoretically investigated from the perturbation calculations of the SHPs for an orthorhombically di, Levitation forces between a finite rectangular superconductor and a spherical magnet. The maximum length for a letter is seven pages. Revista bimestral de la Sociedad Mexicana de Física, en la que el alumno podrá encontrar artículos relacionados a temas de física principalmente pero también cuentan con recursos de matemáticas y química. Distribution of articles . A 3D picture is produced to visualize the boron-10 spatial distribution. Scandinavian Journal of Medicine & Science in Sports. Revista Mexicana de Ciencias de la Cultura Física - Portal principal de la Facultad de Ciencias de la Cultura Física de la Universidad Autónoma de Chihuahua (México). Robert Zamenhof, Saverio Altieri, L. Menichetti, Radioisotopes - Applications in Bio-Medical Science, Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment - NUCL INSTRUM METH PHYS RES A, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Characterization of the Energy Spectrum at the Indiana University Neutron Source, Design parameters and technology optimization of 3He-filled proportional counters for thermal neutron detection and spectrometry applications, First results studying the transmutation of 129 I, 237 Np, 238 Pu, and 239 Pu in the irradiation of an extended nat U/Pb-assembly with 2.52 GeV deuterons, Characterization of the neutron field from the 241Am-Be isotopic source of the IPHC irradiator, 10Boron distribution measurement in laser ablated B 4C thin films using (n,α) reaction and LR115 passive detector, Neutron-induced fission fragment angular distribution at CERN n TOF: The Th-232 case, Characterization of Neutron Beams for Boron Neutron Capture Therapy: In-Air Radiobiological Dosimetry, Influence of neutrons and γ-rays in the Fréjus underground laboratory on the NEMO experiment, Monte Carlo simulation of additional safety control rod for commercial MNSR to enhance safety, Measurements in quasi-monoenergetic neutron beams at the EC-IRMM Van der Graaf accelerator for calibration of the UAB PADC based neutron dosimeter, TRANSPORT AND SHIELDING OF IONISING RADIATION, Boron analysis and boron imaging in biological materials for Boron Neutron Capture Therapy (BNCT), Preparations for phase I clinical trials of boron neutron capture therapy at the mit reactor and the New England Medical Center, The comparison of four neutron sources for Prompt Gamma Neutron Activation Analysis (PGNAA) in vivo detections of boron, Quantitative evaluation of essential and trace elements in nine medicinal plants by IPAA and XRF techniques, Measurement of the U-234 (n, f) cross section with PPAC detectors at the n TOF facility, Filtered fast neutron irradiation system using Texas A&M University Nuclear Science Center Reactor, Wall effect study by PADC detector for an improved proportional counter neutron spectrometer, Alternative method for thermal neutron flux measurements based on common boric acid as converter and LR 115 detectors, Boron Studies in Interdisciplinary Fields Employing Nuclear Track Detectors (NTDs), Complex Workplace Radiation Fields at European High-energy Accelerators and Thermonuclear Fusion Facilities, Production of a 62 PBq 51Cr low energy neutrino source for GALLEX, Tritium breeding mock-up experiments containing lithium titanate ceramic pebbles and lead irradiated with DT neutrons, SSNTD TEchnique in Photo- neutron Applications, Monte-Carlo investigation of radiation beam quality of the CRNA neutron irradiator for calibration purposes, Monte Carlo optimization of sample dimensions of an 241Am–Be source-based PGNAA setup for water rejects analysis, Neutron field characterisation of the OB26 CRNA irradiator in view of its use for calibration purposes, Estimation of neutron-equivalent dose in organs of patients undergoing radiotherapy by the use of a novel online digital detector, Performance of Multisphere Spectrometry Systems, Neutron Spectra Unfolding with Artificial Neural Networks, Neutron area monitor with passive detector, Neutron spectra and H*(10) of photoneutrons inside the vault room of an 18 MV LINAC, 74 Kageji Teruyoshi Clinical results and radiation dose of BSH, BPA-based non-operative BNCT with additional external beam irradiation 7 Barth Rolf What is the future for boron neutron capture therapy? NA DE A FI IC X. Noviembre - diciembre 2021 www.remefis.com.mx. ISSN 1405-8790; Diffusion; Title: REVISTA MEXICANA DE MEDICINA FISICA Y REHABILITACIÓN Country: Mexico. scientist or scholar. Ir al material. A comparison of experimental data with theoretical model calculations using the MCNPX program was performed yielding satisfactory results. Revista Mexicana de Física. Xu-Sheng Liu, Revista Mexicana de Física, diciembre, año/vol. Libros. mex. M. Pacio, REMEFIS.COM.MX Este sitio web utiliza cookies Sports Medicine. Reportes originales de investigación o instrumentación que requieren publicación rápida. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Michael O Adeleye, Sunday Jonah, Raymond Njinga, M. Balata, Frank. E. Suaste-Gomez, DISTRIBUCIÓN GRATUITA, PROHIBIDA SU VENTA Análisis críticos originales del estado del conocimiento en temas específicos de física. Flores-Cuautle. A Monte Carlo simulation of additional safety rods for NIRR-1 HEU and LEU cores was carried out using the MCNP5 version 1.6 code. The design calculations of the rectangular moderator, which were obtained through Monte Carlo simulation, have been verified experimentally through thermal neutron yield measurement using CR-39 nuclear track detectors (NTDs). Abstract: In this paper, the synthesis of nanocomposites of poly(3-hexylthiophene-2,5-diyl)) (P3HT) and cadmium sulfide (CdS) nanoparticles are reported. 1 no. Las cartas tienen una extensión máxima de siete cuartillas. Revista Mexicana de Física. MEMORIAS. Revista Mexicana de Medicina Física y Rehabilitación. A.L. REVISTA MEXICANA. Reviews. 2014. Revista mexicana de física. Revista Mexicana de Fisica | Citations: 553 | Read 1100 articles with impact on ResearchGate, the professional network for scientists. Vera-Herrera, It has been establi, Family of Lamé spheroconal quadrupole harmonic current distributions on spherical surfaces of magnetic induction fields with constant gradients inside and vanishing asymptotically outside [Rev. Aceptamos artículos en español o en inglés relacionados con todas las áreas de la agricultura. 04-2021-071613424100-102 otorgado por el instituto nacional del derecho de autor. the productivity and citation impact of the publications of a C. Bueno, Este sitio utiliza cookies . Reportes originales de investigación o instrumentación que requieren publicación rápida. Articles containing new and original ways of presenting concepts or problems in physics, experiments and designs which can be worked out in laboratories, and original simulation programs. Original research or instrumental papers which require fast publication. México. The Revista Mexicana de Física (Mexican Journal of Physics) publishes original papers of interest to a broad group of readers from the physical science community, in the following sections: 1. Letters. Las cartas tienen una extensión máxima de siete cuartillas. Convocatoria Revista Mexicana de Investigación en Cultura Física y Deporte. There are also other factors such as H-Index, Self-Citation Ratio, SJR, SNIP, etc. Find out more: What is a good impact factor? / LA HORA DEL ODIO. Investigación. Instrumentación. Acceso a lectura en español. R. Perez, "La Revista Mexicana de la Cultura Física" y "Cultura Física y Bienestar Humano" se centran en las áreas de ejercicio físico, actividad física, educación física, biomecánica, salud y bienestar humano, con 10 publicaciones. La Revista Mexicana de Física publica artículos originales, de interés para un grupo significativo de lectores, en las siguientes secciones: 1. D´ ıaz Garc´ ıa y J.L. 1 (marzo 1939- ).-- México: Universidad Nacional autónoma de México, IIS, 1939-v-. By using our site, you agree to our collection of information through the use of cookies. The installed neutron irradiation cell at the USB-Laboratory is employed frequently for applications where the neutron field should be monitored. To get a discrete spectrum of quasinormal frequencies for the scalar type electromagnetic field we fin, Glucose in aqueous solution thermal characterization by photopyroelectric techniques. 4. The installed neutron irradiation cell at the USB-Laboratory is employed frequently for applications where the neutron field should be monitored. Impact factor (IF) is a scientometric factor based on the yearly average number of citations on articles published by a particular journal in the last two years. ENSENANZA REVISTA MEXICANA DE F˜ ´ISICA E 52 (1) 78-83 JUNIO 2006 Cartas. useof impact factors of science journals easier. 51, número enseñanza 2 Sociedad Mexicana de Física . received by a journal and the importance or prestige of the journals where 2. La Mesa Directiva de la Sociedad Mexicana de Física, convoca al LXV Congreso Nacional de Física, que se celebrará del 02 al 07 de octubre del 2022 en la Cd. The following reactor core physics parameters were determined; neutron flux distribution within the core with safety rods withdrawn, control rod (CR) worth for each rod, core excess reactivity, shutdown margin and some kinetic parameters. The result suggests that a gradient in the boron distribution exists to almost a factor of three. Facultad de Ciencias, Universidad Autonoma de Mexico. Piso), A.P. 2 Abr-Jun, Pág. A comparison of experimental data with theoretical model calculations using the MCNPX program was performed yielding satisfactory results. Wasim, O. González-Amezcua. SCImago Journal Rank (SJR indicator) is a measure of scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from. Education. Structural changes in ZrOxNy/ZrO2 coatings deposited through spray pyrolisis-nitriding. Esta página y sus contenidos pueden ser utilizados y reproducidos con fines no lucrativos, siempre y cuando no se mutile, se cite la fuente completa y su dirección electrónica. Año 2019, Vol. Research. 3. Mex. Enseñanza. The passive device is a Kodak-Path`e LR-115 externally coated with a thin (0,1mm) binary glass metal strip Fe75B25 where the 10B(n,®)7Li reaction converts free neutrons into alpha particles that are registered as etched tracks. A. Cruz-Orea, Information about the spatial and energy distribution of neutrons in the volume of the lead target and the uranium blanket was obtained with sets of activation threshold detectors (Al, Y and Au) and solid state nuclear track detectors (SSNTD). A. López-Ortega. Durante los últimos años, los responsables de la Revista Mexicana de Física, la Revista Mexicana de Física E y la Revista Mexicana de Física S, hemos realizado esfuerzos para fortalecer la presencia de estas publicaciones en nuestra página Web ( http://rmf.smf.mx). A. León-Galicia. M.E. Caracas, Venezuela.  All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License, Circuito exterior s/n (Facultad de Ciencias, Departamento de Física 2o. D. Montiel-Condado, Programas de Licenciatura; Programas de Posgrado; Departamento de Física, 2do piso, Facultad de Ciencias UNAM, C.P. La Revista Española de Física, publicada por la Real Sociedad Española de Física con una periodicidad trimestral, está dedicada a aspectos académicos, pedagógicos y sociales de la física. Rehabilitación. 60, Núm. Sus objetivos son dar a conocer trabajos científicos originales en español, servir de instrumento de opinión y debate y facilitar la educación continuada para todos los interesados en . The irreversibilities of each cycle are: finite rate heat transfer between the working fluid and the external heat sources, internal dissipation of the working fluid, and, Resumen: Se optimiza un modelo de planta de potencia irreversible con n ciclos tipo Carnot. This thesis work was done in the frame of the study of the neutron-induced fission of actinides and subactinides at the CERN n TOF facility using a fast Parallel Plate Avalanche Counters (PPACs) setup. These papers present and discuss physical principles applied in a new way to instrumentation and techniques for the solution of physical problems. Please check the journal website for updated information prior to submission. por el Instituto de Investigaciones sociales.-- vol. Avignone III, L. Carbone, Radioisotopes - Applications in Bio-Medical Science, Haydn Barros, Ruben Ingles Atauchi Ingles, Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment - NUCL INSTRUM METH PHYS RES A, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Characterization of the Energy Spectrum at the Indiana University Neutron Source, Verification of design calculations of a PGNAA setup using nuclear track detectors, Design parameters and technology optimization of 3He-filled proportional counters for thermal neutron detection and spectrometry applications, Direct Measurement of Neutron-Neutron Scattering, n , α ) Reaction study with LR115 for binary glass metal boron distribution, Boron analysis and boron imaging in biological materials for Boron Neutron Capture Therapy (BNCT, First results studying the transmutation of 129 I, 237 Np, 238 Pu, and 239 Pu in the irradiation of an extended nat U/Pb-assembly with 2.52 GeV deuterons, Characterization of the neutron field from the 241Am-Be isotopic source of the IPHC irradiator, Neutron-induced fission fragment angular distribution at CERN n TOF: The Th-232 case, Reaction study with LR-115 for binary glass metal boron distribution, Characterization of Neutron Beams for Boron Neutron Capture Therapy: In-Air Radiobiological Dosimetry, Understanding Neutron Radiography Reading VII-NRHB Part 1 of 2, Influence of neutrons and γ-rays in the Fréjus underground laboratory on the NEMO experiment, Monte Carlo simulation of additional safety control rod for commercial MNSR to enhance safety, Measurements in quasi-monoenergetic neutron beams at the EC-IRMM Van der Graaf accelerator for calibration of the UAB PADC based neutron dosimeter, Production of a 62 PBq 51Cr low energy neutrino source for GALLEX, CUORE: a cryogenic underground observatory for rare events, Workplace characterisation in mixed neutron-gamma fields, specific requirements and available methods at high-energy accelerators, Measurement of the U-234 (n, f) cross section with PPAC detectors at the n TOF facility, Transmutation of 129I and 237Np using spallation neutrons produced by 1.5, 3.7 and 7.4GeV protons, Filtered fast neutron irradiation system using Texas A&M University Nuclear Science Center Reactor, Methods to Collect, Compile, and Analyze Observed Short-lived Fission Product Gamma Data, Boron Studies in Interdisciplinary Fields Employing Nuclear Track Detectors (NTDs), Complex Workplace Radiation Fields at European High-energy Accelerators and Thermonuclear Fusion Facilities, Tritium breeding mock-up experiments containing lithium titanate ceramic pebbles and lead irradiated with DT neutrons, SSNTD TEchnique in Photo- neutron Applications, Monte-Carlo investigation of radiation beam quality of the CRNA neutron irradiator for calibration purposes, Neutron field characterisation of the OB26 CRNA irradiator in view of its use for calibration purposes, Alternative method for thermal neutron flux measurements based on common boric acid as converter and LR 115 detectors, Estimation of neutron-equivalent dose in organs of patients undergoing radiotherapy by the use of a novel online digital detector, Performance of Multisphere Spectrometry Systems, Neutron area monitor with passive detector, Neutron spectra and H*(10) of photoneutrons inside the vault room of an 18 MV LINAC, 74 Kageji Teruyoshi Clinical results and radiation dose of BSH, BPA-based non-operative BNCT with additional external beam irradiation 7 Barth Rolf What is the future for boron neutron capture therapy?

Instituto De Bellas Artes, Fiscalización Municipal Trabajo, Canjear Puntos Bbva Perú, Conafovicer Navidad 2021, Tierra Preparada 4 Estaciones, Acreditar Idioma Pucp, Temperatura En Lima Hoy En La Noche, Noticias De Abuso Infantil Perú, Es Obligatorio Responder Una Carta Notarial Perú, Que Pasa Cuando Haces Ejercicio Por Primera Vez, Comprar Directv Prepago,