16,489 research outputs found
Self-Referencing Fiber-Optic Intensity Sensors Using Ring Resonators and Fiber Bragg Gratings
An improved ring resonator self-referencing technique in a new reflection configuration for remote fiber-optic intensity sensors is demonstrated using fiber Bragg gratings. Sensor sensitivity doubles and a single fiber lead is used. The sensor is interrogated at two subcarrier frequencies having a high rejection of interference from laser source intensity fluctuations and loss in the fiber lead. We experimentally demonstrate the efficiency of the new reflection configuration, the usefulness of the theoretical model proposed, and discuss design parameters for optimum insertion lossesThis work was supported in part by CICYT (TIC2003-03783 and TEC2006-13273-C03-03-MIC), in part by UC3M (FAVICOBIS), in part by CAM (FACTOTEM-CM:S-0505/ESP/000417), and in part by COST 299.Publicad
La sociedad contra el Estado… egipcio: Enfoques etnohistóricos de una revolución inacabada
Los acontecimientos que acabaron con el gobierno de Hosni Mubarak en Egipto el año 2011 supusieron una sorpresa para muchos investigadores, periodistas y, tambiĂ©n, egipcios. Sin embargo, una mirada a la historia de la implantaciĂłn del Estado contemporáneo en el paĂs de los faraones desde el siglo XIX, revela una sucesiĂłn de levantamientos populares contra los distintos gobiernos. En Oriente medio y el Magreb, la calle –el hara, el ashawbiyat o los barrios autoconstruidos– ha sido histĂłricamente el lugar principal para ejercer la polĂtica por el pueblo –shab–, todos aquellos ausentes, aparentemente, de las posiciones de poder. Más allá de la sorpresa, la calle sigue siendo el lugar más importante para la expresiĂłn sonora de las quejas colectivas del pueblo, cuando los regĂmenes locales han ignorado y reprimido sus demandas. El artĂculo propone una revisiĂłn desde la polĂtica tal y como se entiende en AntropologĂa de esos levantamientos entendidos como “armas de los pobres” que permitan contextualizar los sucesos revolucionarios en los paĂses árabes como una forma histĂłricamente arraigada de influir en la polĂtica de los estados.
Palabras claves: Oriente Medio, Egipto, levantamientos populares, polĂtica, etnohistoria.
Paraules claus: Primavera árabe, Magreb, resistencia, revueltas, colonialismo.Los acontecimientos que acabaron con el gobierno de Hosni Mubarak en Egipto el año 2011 supusieron una sorpresa para muchos investigadores, periodistas y, tambiĂ©n, egipcios. Sin embargo, una mirada a la historia de la implantaciĂłn del Estado contemporáneo en el paĂs de los faraones desde el siglo XIX, revela una sucesiĂłn de levantamientos populares contra los distintos gobiernos. En Oriente medio y el Magreb, la calle –el hara, el ashawbiyat o los barrios autoconstruidos– ha sido histĂłricamente el lugar principal para ejercer la polĂtica por el pueblo –shab–, todos aquellos ausentes, aparentemente, de las posiciones de poder. Más allá de la sorpresa, la calle sigue siendo el lugar más importante para la expresiĂłn sonora de las quejas colectivas del pueblo, cuando los regĂmenes locales han ignorado y reprimido sus demandas. El artĂculo propone una revisiĂłn desde la polĂtica tal y como se entiende en AntropologĂa de esos levantamientos entendidos como “armas de los pobres” que permitan contextualizar los sucesos revolucionarios en los paĂses árabes como una forma histĂłricamente arraigada de influir en la polĂtica de los estados.
Palabras claves: Oriente Medio, Egipto, levantamientos populares, polĂtica, etnohistoria
Entre la modernidad y la tradiciĂłn: modos de ser joven en el Cairo
En general, las aproximaciones a las compartimentaciones culturales del ciclo vital han sido establecidas rĂgidamente y casi sin relaciĂłn. En el caso de las representaciones juveniles en contextos occidentales, más que como un continuum en ese ciclo, se presenta como una etapa con unas formas prototĂpicas que parecen invadir otras etapas etáreas. De esa manera parece valioso para el conjunto social que las prácticas y virtudes de la juventud se extiendan a la vejez o la vida adulta. En este articulo, trato de cuestionar la pretendida universalidad de esa forma de contemplar la etapa juvenil a partir de la presentaciĂłn de un caso etnográfico de otro modelo cultural para ese momento de la vida. En El Cairo, el objetivo de los jĂłvenes no es alargar indefinidamente esa situaciĂłn sino acabarla cuánto antes con el matrimonio para alcanzar la madurez, la plenitud social de la vida adulta. En Ăşltima instancia lo que se pretende es presentar una forma de entender la juventud arraigada en una tradiciĂłn cultural diferente de la occidental que permite cuestionar la validez del uso del tĂ©rmino en otros contextos sociales
Correlatos neuronales de las emociones sociales de culpa, vergĂĽenza y orgullo
Tesis inĂ©dita de la Universidad Complutense de Madrid, Facultad de PsicologĂa, Departamento de PsicobiologĂa y MetodologĂa de las Ciencias del Comportamiento, leĂda el 20-07-2021Brain research on emotions is generally focused on basic emotions such as anger, fear, sadness, joy, contempt, surprise and disgust. These basic emotions, are by far, the most well understood. They are easy to approach, presumably universal and linked to other primates and non human animals. These characteristics have permitted a broader search. Social emotions as guilt, shame, embarrasment and pride, nevertheless, remain largely unexplored, although our life is tainted with them,.Social emotions are different to basic ones. They require complex cognitive and evaluative aspects, and not only emotional. In experimental settings are usually studied stemming from imagining or remembering situations removed from social reality. Participants imagines him/herself acting in a precise situation, or tries to restore a memory, relatively recent, in which that emotion has been felt in a similar social context. This experimental setting is very different to social life, where social emotions emerge as a reaction to self predictions, precise contexts, standards and norms...La investigaciĂłn cerebral tradicional sobre las emociones se centra en las llamadas emociones básicas, siendo ira, miedo, tristeza, alegrĂa y asco las más estudiadas. Su facilidad de estudio, ubicuidad y posible vĂnculo con otros primates y animales no humanos, han posibilitado una extensa investigaciĂłn. Las emociones sociales, entre las que destacan principalmente la culpa, la vergĂĽenza, el orgullo y el bochorno, a pesar de que nuestra vida está teñida de ellas, permanecen aĂşn con muchĂsimos aspectos por explorar. Estas emociones sociales a diferencia de las básicas, implican aspectos cognitivos y evaluativos complejos, no solo emocionales. En el ámbito experimental se suelen elicitar a partir de situaciones imaginadas o recordadas, en los que el sujeto se visualiza a sĂ mismo respondiendo en una situaciĂłn precisa, o trata de rescatar de su memoria una experiencia relativamente reciente en la que haya sentido esa emociĂłn en un contexto social similar. Evidentemente este modo experimental está muy lejos de nuestra realidad social cotidiana en la que se las emociones sociales, surgen in situ, como respuesta a predicciones propias, contextos precisos, normas y acuerdos comunes, que toda vida social requiere...Fac. de PsicologĂaTRUEunpu
Social security and the search behaviour of workers approaching retirement
This paper explores the links between unemployment, retirement and their associated public insurance programs. It is a contribution to a growing body of literature focused on a better understanding of the labor behavior of advanced—age workers, which has gained importance as the pension crisis looms. The analysis combines the development of a new theoretical model and a detailed exploration of the empirical regularities using the Spanish Muestra Continua de Vidas Laborales (MCVL) dataset. The model is a extension of the standard search model, designed to reproduce the non—stationary environment faced by workers approaching retirement and to explore the interaction of unemployment benefits and retirement pensions. Via calibrated simulations we show that the basic empirical reemployment and retirement patterns can be rationalized as the optimal responses to both the labor market conditions and the institutional incentives. Generous Unemployment Benefits (for durations of up to two years) together with very significant early retirement penalties, make optimal to stay unemployed without searching for large groups of unemployed workers. This moral hazard problem can he substantially alleviated through institutional reform. Setting the early retirement penalties according to the age when the individual withdraws from the labor force (rather than when he/she claims the pension for the first time) seems particularly beneficial. It increases the labor supply, reduces the financial cost for the social security system and generate enough extra resources to compensate for the welfare loss of those unemployed directly hit by the reform.Unemployment search, job benefit, retirement
Na+-dependent NO3- uptake in leaf cells of the seagrass Posidonia oceanica (L.) Delile
Posidonia oceanica (L.) Delile is an endemic Mediterranean seagrass of recognized ecological significance and, as other seagrasses, this species has secondarily adapted to live in the marine environment. In this alkaline medium with a high Na+ concentration (0.5 M), the high inwardly directed electrochemical potential gradient for sodium is used in the seagrass Zostera marina to energize the uptake of nitrate1 and phosphate that usually occur at concentration below 10 µM. Here we summarize several evidences for the operation of a sodium-dependent high-affinity nitrate transport system at the plasma membrane of the mesophyll leaf cells of P. oceanica.
Leaf cells of P. oceanica possess a H+-ATPase as a primary pump, exhibit a plasma membrane potential (Em) of -174 ± 10 mV and show reduced Na+ permeability. The addition of micromolar nitrate concentrations induces membrane depolarizations that show saturation kinetics. Curve fitting of the values renders a semisaturation constant (Km) of 21.3 ± 6.6 μM and a maximum depolarization (Dmax) of 7 ± 1 mV. In dark conditions, Dmax decreases by fifty percent but no significant effect is observed on the Km value. On the other hand, nitrate induced depolarizations show sodium dependence. The depolarizations induced by 100 µM NO3- in media containing increasing Na+ concentrations (from 0 to 250 mM) show saturation kinetics, rendering a Km value of 16 ± 5 mM Na+. Moreover, the depolarization induced by 100 µM NO3- is accompanied by a simultaneous increase of cytosolic sodium, measured by Na+-sensitive microelectrodes, of 0.4 ± 0.2 mM above the resting cytosolic sodium concentration (17 ± 2 mM).
Finally, nitrate uptake rates, measured in depletion experiments, decreases by 50% and 80% in dark conditions and in the absence of Na+, respectively, compared with control conditions (0.5 M Na+ and light).
All together, these results strongly suggest that NO3- uptake in P. oceanica leaf cells is mediated by a high-affinity nitrate carrier that uses Na+ as the driving ion.
1 Rubio et al. (2005). J. Exp. Bot, 412: 613-622.
Project Funding: CTM 2011-30356. (MEC)Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Tropical Medicine: Sleeping Sickness
[ES]Raquel Cade (Angie Dickinson), una misionera,
viaja al Congo Belga en 1939 para ayudar como enfermera al Dr. Bikel (Douglas Spencer) en el Hospital de la Misión de Dibela. Nada más llegar, el médico fallece de un ataque cardiaco y Raquel tiene que enfrentarse con las costumbres y creencias religiosas de los nativos. El coronel Henry Derode (Peter Finch), el jefe del destacamento del Ejército belga, le ofrece ayudarla a abandonar el lugar pero no acepta. Las cosas van mal, pero todo cambia cuando se ve obligada a intervenir a un niño de una apendicitis aguda, a partir de ese momento la tribu estará dividida. Su situación mejora al estrellarse un avión en las proximidades y atender al único superviviente, un médico llamado Paul Wilton (Roger Moore).[EN]Raquel Cade (Angie Dickinson) is a missionary
nurse who, in 1939, travels to Belgian Congo in order to help Dr. Bikel (Douglas Spencer) in Dibella’s Mission Hospital. Just after her arrival the doctor dies because of a heart attack, and Rachel has to confront the native’s
habits and religious beliefs. Colonel Henry Derode (Peter Finch), the detachment commander of the Belgian army, offers her his help to abandon the place, but she does not accept it. Things seem to go wrong, but everything changes when she has to perform an appendicitis surgery on a child. As of that moment, the tribe is divided.
Her situation improves when an airplane crashes near there and she assists the only survivor, a doctor called Paul Wilton (Roger Moore)
PWM Control of a Buck Converter with an Amorphous Core Coil
Pulse-width modulation is widely used to control electronic converters. One of the most topologies used for high DC voltage/low DC voltage conversion is the Buck converter. It is obtained as a second order system with a LC filter between the switching subsystem and the load. The use of a coil with an amorphous magnetic material core instead of air core lets design converters with smaller size. If high switching frequencies are used for obtaining high quality voltage output, the value of the auto inductance L is reduced throughout the time. Then, robust controllers are needed if the accuracy of the converter response must not be affected by auto inductance and load variations. This paper presents a robust controller for a Buck converter based on a state space feedback control system combined with an additional virtual space variable which minimizes the effects of the inductance and load variations when a not-toohigh switching frequency is applied. The system exhibits a null steady-state average error response for the entire range of parameter variations. Simulation results are presented
Development of an electrochemical maltose biosensor
In this work, electrochemical maltose biosensors based on mutants of the maltose binding protein (MBP) are developed. A ruthenium II complex (Ru II ), which is covalently attached to MBP, serves as an electrochemical reporter of MBP conformational changes. Biosensors were made through direct attachment of Ru II complex modified MBP to gold electrode surfaces. The responses of some individual mutants were evaluated using square wave voltammetry. A maltose-dependent change in Faradic current and capacitance was observed. It is therefore demonstrated that biosensors using generically this family of bacterial periplasmic binding proteins (bPBP) can be made lending themselves to facile biorecognition element preparation and low cost electrochemical transduction
Cabero, J. & GarcĂa, F. (2015). Realidad aumentada: TecnologĂa para la formaciĂłn. Madrid: SĂntesis [Reseñas]
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