Mostrando recursos 1 - 20 de 307.169

  1. The impact of memristive devices and systems on nonlinear circuit theory

    Riaza Rodríguez, Ricardo
    In this talk we present a discussion of the impact of memristive devices (memristors, memcapacitors and meminductors) and memristive systems on the fundamentals of nonlinear circuit theory and also on electronics. The interest on this topic has increased continuously since the design in 2008 of a nanoscale device with a charge-flux characteristic, displaying a very promising industrial scope in memory design. We survey theoretical concepts and also discuss some recent applications in this area, providing references for further study.

  2. Stability breakdown along a line of equilibria in nonlinear circuits with memristors

    Riaza Rodríguez, Ricardo
    The design in 2008 of a device with a memristive characteristic has had a great impact in electronics, specially at the nanometer scale. This device, whose existence was predicted by Leon Chua in 1971 for symmetry reasons, is governed in a flux-controlled setting by a relation of the form i = W(ϕ)v, and systematically leads to the presence of non-isolated equilibria. In this communication we examine how the stability of such manifolds of equilibria may break down when normal hyperbolicity fails. This phenomenon may be due to the transition of an eigenvalue either through the origin or through infinity. Our approach is a...

  3. Evaluación de la diagénesis ósea mediante el uso de microscopía electrónica de barrido (meb): Aproximaciones analíticas aplicables a muestras arqueológicas

    Barrientos, Gustavo; Sarmiento, Patricia L.; Galligani, Paula E.
    The aim of this paper is to review analytic approaches to bone diagenesis based on the use of scanning electron microscopy (SEM). In order to do this, we present a) a synthesis of current knowledge about diagenetic processes affecting the histological integrity of human and faunal skeletal remains in terrestrial sedimentary deposits; b) a brief description of the general principles of electron microscopy, particularly of SEM, and c) a comparison of the main differences -in terms of requirements, recoverable information, and associated pros and cons- between analyses centered on the use of either of the two main kinds of images...

  4. The effect of electronic learning systems on the employee's commitment

    Zareie, Batool; Navimipour, Nima Jafari
    E-learning as a popular learning approach utilized by many organizations has become an important trend in recent years. It generally refers to the use of computer network technology, primarily over an intranet or through the Internet, to deliver information and instruction to individuals. It allows training to reach diverse and geographically dispersed workforces in a cost-efficient manner, and can take place on-demand and at a lesser cost than on-site training. Also, employee commitment is a dominant source of competitive advantage of many organizations and thus, has been drawn to its reported ability to solve intractable organizational challenges. Therefore, this study...

  5. Báez, Fernando (2013), Los primeros libros de la Humanidad: el mundo antes de la imprenta y el libro electrónico. Madrid: Fórcola, 621 pp.


  6. La hipermedia

    Arango Martínez, José Samuel
    Un día cualquiera de nuestra vida actual, es definitivamente muy diferente a un día típico de hace cinco años.Nos despertó el celular y se encendió el televisor en el noticiero de la cadena que nos gusta. Antes de saludar a la familia, miramos en el correo electrónico lo que nos había llegado en la noche. Sacamos de las páginas web el menú para el almuerzo y la cena. Ojeamos los periódicos en Internet. Le replicamos a un columnista que afirmaba, en nuestra opinión, barbaridades.Recibimos la actualización de los blogs y sitios webs a los que estamos suscritos y en el...

  7. Los niños menores de tres años y la televisión: perspectivas de investigación y debate (1999-2010)

    Sánchez, Adriana Rodríguez
    En este texto se reproduce la introducción y las conclusiones de la investigación “Los niños menores de tres años y la Televisión: Perspectivas de investigación y debate (1999-2010)” publicada por el Ministerio de Cultura de Colombia. En la revisión bibliográfica realizada, se establece que la presencia de la televisión y de otros medios electrónicos es central en la vida cotidiana de los niños, y que el número de horas que pasan frente a la pantalla tiende a incrementarse con el tiempo, con la edad y si tienen televisor en su cuarto.Se encuentra también que aunque buena parte de los videos yprogramas de televisión dirigidos a niños menores de tres años señalan que...

  8. La comunicación entre los ciudadanos y los representantes políticos a través del correo electrónico. : Análisis del caso de la delegación española en el Parlamento Europeo durante los años 2013 y 2014

    Puchades Arce, Francisco Javier
    La participación ciudadana en los asuntos públicos ha encontrado un nuevo campo de expansión en las tecnologías de la información, favoreciendo la implicación política de las personas. El presente trabajo analiza la comunicación entre ciudadanos y eurodiputados españoles a través del correo electrónico. Para ello, el investigador ha dirigido un grupo de individuos que, durante tres oleadas, se han comunicado con los europarlamentarios a través de esta vía. Junto con el análisis cuantitativo se ha realizado un análisis de contenido para evaluar la calidad de las respuestas. Las conclusiones señalan bajos porcentajes de respuesta en el uso que los eurodiputados...

  9. Criterios para la selección de información Científica Odontológica en la World Wide Web

    Espinoza, Norelkys
    Abtract This paper describes a research strategy developed as didactic strategy during 2002, in Computación, subject which is part of the curricular unit Introducción a la Investigación, for undergraduate students, Dentistry Faculty, Universidad de Los Andes, Mérida, Venezuela. Based on constructivism, one of the strategies for selecting scientific dental information in the World Wide Web was applied. Digital information is selected by using two verifying information techniques: Content Analysis and Epistemological Watching, ordinarily applied for written texts. After word, this information will be used to support a documental research. Moreover, three fundamental concepts of the electronic communication model, actually used...

  10. Manifestaciones Periodontales en pacientes infectados con el Virus de la Inmunodeficiencia humana (Vih) y síndrome de Inmunodeficiencia adquirida (Sida) (Revisión Bibliográfica)

    López A, Luis Ernesto; Borges, Nora; Salazar, Carmen Rosa; Salazar V., Juan Luis
    Abstract The objective of this study was to gather and to systematize the information with relationship to the most frequent periodontal alterations in patient with the human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS). For their execution it was appealed to the techniques of the investigation monografic that allowed: to get de botton in the knowledge of the problem, with support, mainly, in previous scientific works, information and data disclosed by printed, audiovisual and electronic means. This way, the gingivitis and periodontitis related with HIV/AIDS and the measures of security and hygiene are detailed to prevent the infection for...

  11. Evaluación del grabado del esmalte en piezas con ápice inmaduro y maduro utilizando ácido ortofosfórico al 37% por medio de microscopia electrónica de barrido

    Meléndez Ruiz, José Luis; Varela Ochoa, Rubén; Cueto Arvizu, Guillermo; Mondragón Espinoza, Jaime Darío; Carrillo Palacios, Lorena; Coronado, Edith; García López, Eliezer; Rojo Hurtado, Claudia María; Orozco Varela, Karin Anette
    The purpose of this study was to evaluate enamel etching with orthophosphoric acid at 37% using different time on young teeth (inmatured apex), analyzed with electronic microscopy (MEB). 40 bicuspids were the sample recently extracted, 20 with inmatured apex and 20 fully developed. Each tooth was selected and etched for 15, 30, 45 and 60 seconds and then analyzed by the MEB. Data was evaluated statistically with the Ji ² (Chi square). There were no significantly differences neither between groups nor times of etching at 15, 30, 45 except in fully developed teeth etched at 60 seconds were we found...

  12. La ley foral de la transparencia y del gobierno abierto

    Razquin Lizarraga, José Antonio
    This paper provides an analysis of the Law 11/2012 about Transparency and Open Goverment adopted by Foral Community of Navarra. This Act rules the access to information and public participation in Administration of Community of Navarra, considering that the aim is to achieve an open, transparent, participative and responsible Public Administration, using electronic means.

  13. Solution-processed transparent dielectric based on spin-on glass for electronic devices

    Domínguez-Jiménez, M.A.; Luna López, J.A.; Moreno, M.; Orduña, A.; García, M.; Alcántara Iniesta, S.; Soto, S.
    In this work, the fabrication and characterization of MOS and MIM capacitors using a solution-processed dielectric based on spin-on glass (SOG) solution is presented. The SOG solution is diluted with deionized water (DI) in order to make easier the evaporation of the organic material presented in the SOG. The films are highly transparent in the visible range, which makes feasible they use in transparent electronics. The capacitance-voltage and current-voltage characteristics of the MOS and MIM capacitors demonstrate the application of the solutionprocessed SOG/DI film as dielectric for electronic devices.

  14. Convergence of resonance expansions in quantum wave buildup

    Hernandez Maldonado, Alberto; Romo, Roberto; Villavicencio, Jorge
    The convergence of stationary and dynamical resonance expansions that involve complex eigenenergies of the system is analyzed in the calculation of the electronic probability density along the internal region of a resonant structure. We show that an appropriate selection of the resonance contributions leads to results that are numerically indistinguishable from the exact Hermitian calculation. In particular, the role played by the anti-resonances in the convergence process is emphasized. An interesting scaling property of the Schrödinger equation, and the stationary resonance expansion, useful for the analysis of convergence of families of systems, is also demonstrated. The convergence of a dynamical...

  15. A cluster randomised controlled trial of educational prompts in diabetes care: study protocol.

    Foy, R; Hawthorne, G; Gibb, I; Eccles, MP; Steen, N; Hrisos, S; White, T; Croal, BL; Grimshaw, JM
    Background: laboratory services have a central role in supporting screening, diagnosis, and management of patients. The increase in chronic disease management in primary care for conditions such as diabetes mellitus requires regular monitoring of patients' biochemical parameters. This process offers a route for improving the quality of care that patients receive by using test results as a vehicle for delivering educational messages as well as the test result itself. Aim: to develop and evaluate the effectiveness of a quality improvement initiative to improve the care of patients with diabetes using test report reminders. Design: a programme of four cluster randomised...

  16. Analysis and Design of an Isolated Single-Stage Three-Phase Full-Bridge with Current Injection Path PFC Rectifier for Aircraft Application

    Zhao, Sisi; Silva, M.; Oliver Ramírez, Jesús Angel; Alou Cervera, Pedro; García Suárez, Oscar; Cobos Márquez, José Antonio
    Nowadays there has been an important increase of electric equipment in modern aircraft which leads to a rising demand of electrical power. This highlights the necessity of efficient, reliable and high energy density power converters which rectify three-phase 115V ac to 270V dc for power distribution. This paper presents an isolated single-stage PWM rectifier with the integration of a current injection path and a full-bridge topology (IS2 FBCIP PFC Rectifier). The operating principle and modulation method are presented together with design guidelines for the rectifier. Simulation results are shown to validate the functionality of the topology. The advantages of the...

  17. Pressure management in water distribution systems: current status, proposals, and future trends

    Vicente Gonzalez, David Jesus; Garrote de Marcos, Luis; Sánchez Calvo, Raúl; Santillan Sanchez, David
    Pressure management (PM) is commonly used in water distribution systems (WDSs). In the last decade, a strategic objective in the field has been the development of new scientific and technical methods for its implementation. However, due to a lack of systematic analysis of the results obtained in practical cases, progress has not always been reflected in practical actions. To address this problem, this paper provides a comprehensive analysis of the most innovative issues related to PM. The methodology proposed is based on a case-study comparison of qualitative concepts that involves published work from 140 sources. The results include a qualitative...

  18. Event-based design for mitigating energy in electronic systems

    Fesquet, Laurent; Simatic, J.; Darwish, Amani; Cherkaoui, Abdelkarim
    International audience

  19. What does Left Dislocation Syntactically Comprise? Evidence from Late Modern English

    Tizón-Couto, David
    [Abstract] As part of a major project on left dislocation in the recent history of the English language, this paper aims at defining the Left Dislocation phenomenon taking data from a late Modern English corpus as a point of departure. Given that the label LD has not been uniformly applied to the same periphery phenomena across the board in the specialized literature, it is crucial to make clear what I understand and label as LD in order to continue on with functional and pragmatic analyses in my future research. Furthermore, the aim of this paper is to point out several...

  20. Feasibility of extracting data from electronic medical records for research: an international comparative study

    van Velthoven, Michelle Helena; Mastellos, Nikolaos; Majeed, Azeem; O’Donoghue, John; Car, Josip

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