El «acorazado Sebastopol» y la censura cinematográfica: una relación amor odio

I Congreso Internacional de Historia y Cine: 5, 6, 7 y 8 de Septiembre de 2007

Coordination Environment Prevents Access to Intraligand Charge-Transfer States through Remote Substitution in Rhenium(I) Terpyridinedicarbonyl Complexes

Six rhenium(I) κ3N-dicarbonyl complexes with 4′-(4-substituted phenyl)terpyridine ligands were evaluated in their ground and excited states. These complexes, bearing substituents of different electron-donating strengths—from CN to NMe2—were studied by a combination of transient IR (TRIR), electrochemistry, and IR spectroelectrochemistry, as well as time-dependent density functional theory (TD-DFT). They exhibit panchromatic absorption and can act as stronger photoreductants than their tricarbonyl counterparts. The ground- and excited-state potentials, absorption maxima, and lifetimes (250–750 ps) of these complexes correlate well with the Hammett σp substituent constants, showing the systematic effect of remote substitution in the ligand framework. TRIR spectroscopy allowed us to assign the lowest singlet and triplet excited states to a metal-to-ligand charge-transfer (MLCT) character. This result contrasts our previous report on analogous κ2N-tricarbonyl complexes, where remote substitution switched the character from MLCT to intraligand charge transfer. With the help of TD-DFT calculations, we dissect the geometric and electronic effects of coordination of the third pyridine, local symmetries, and increasing conjugation length. These results give valuable insights for the design of complexes with long-lived triplet excited states and enhanced absorption throughout the visible spectrum, while showcasing the boundaries of the excited-state switching strategy via remote substitution

Nuevas perspectivas en torno a la política de pensiones de la Junta para Ampliación de Estudios: modelos de encuentro con Europa de la Universidad española.

Sin resume

El criterio de relevancia científica y la organización histórica por generaciones de la ciencia española

Si la aportación de nuestro país a las Artes ha constituido tradicionalmente una referencia a nivel internacional, la Ciencia española ha tardado muchos siglos en aproximarse a los estándares de los países más avanzados de nuestro entorno. Realmente, a las puertas de la Guerra Civil podíamos presumir de haberlo logrado, y de ello se han hecho eco numerosos historiadores de nuestro pasado científico. En este artículo se presenta una organización histórica de la Ciencia española contemporánea que pretendemos sea novedosa. Atendiendo al criterio de relevancia internacional de sus respectivas contribuciones científicas, a las tradicionalmente conocidas como generaciones de sabios y generaciones intermedias añadimos una nueva categoría: la de las generaciones tuteladas, justificando convenientemente su caracterización

Valoración del profesorado en formación de educación infantil sobre su participación activa en itinerarios patrimoniales

Research on what happens in early childhood teacher training classrooms when working on cultural heritage is still of little significance with respect to primary and secondary education. This work presents an analysis of the evaluations of a specific proposal, with students in initial training in early childhood education, participating in a heritage-based didactic itinerary, with trainees interacting in all the didactic processes. The research has been carried out in a specific group, with 52 students from the University of Cordoba. The objective is to evaluate the conceptual and competence contributions of this teaching practice to the training of future teachers. It is an exploratory and descriptive study, with two tools for data collection: a semi-structured questionnaire and closed questions; and a focal study. The results are quite positive, although it is necessary to continue considering a globalized and interdisciplinary heritage education, leaving aside methodologies of contemplation and exaltation of monumental heritage

Nuevas perspectivas en torno a la política de pensiones de la Junta para Ampliación de Estudios: modelos de encuentro con Europa de la Universidad española.

Sin resume

Analysis of injection-locked pulsed waveform oscillators

The injection-locked behaviour of a high efficiency pulsed waveform oscillator is analyzed in detail. The design is based on a closed-loop configuration, loaded with a short nonlinear transmission line (NLTL). A new technique is provided to predict the effect of the circuit elements on the synchronization bandwidth, which enables an overall optimization of the oscillator design, considering efficiency, pulse width and locking interval. The phase-noise minimum in free-running conditions, obtained for particular values of the design parameters, is investigated through the use of phase sensitivity functions. The impact of this minimum on the noise spectrum in injection-locked conditions is also studied. The techniques have been applied to a pulsed-waveform oscillator at 0.9 GHz

Stability analysis of oscillators driven with multi-harmonic sources

An investigation of the synchronization behavior of oscillators driven with multi-harmonic sources is presented. The occurrence of ultra-subharmonic synchronization is demonstrated, which gives rise to a multi-resonance behavior versus the fundamental input frequency. When this frequency decreases, instabilities arise in the low amplitude intervals of the multi-resonance curve, and both flip and Hopf bifurcation may delimit the stable synchronization intervals. The study provides a generalization of the theory of fundamentally locked oscillators to the case of oscillators driven with multi-harmonic signals. It is illustrated through application to an oscillator at 5.7 GHz.This work has been supported by the Spanish Government under contract TEC2011-29264-C03-01

Subharmonically injection-locked oscillator using a nonlinear transmission line

This work describes a first realization of an oscillator driven through a nonlinear transmission line (NLTL). In this way, the oscillator is able to synchronize to a sinusoidal injection source of much lower frequency. This can be understood as the result of two processes: high harmonic generation in the NLTL and frequency multiplication plus mixing in the oscillator device. The concept can be applicable in ultrawideband signal oscillators where synchronization should enable a fast oscillation start-up and facilitate the modulation process. As an example, it has been used here to obtain a pulsed-envelope oscillator at 6 GHz injected with a sinusoidal signal in the order of 100 MHz. The operation bands have been analyzed with a Poincaré map technique, allowing the detection of the bifurcation phenomena that delimit the stable synchronization ranges. For an understanding of the phase-noise spectrum, this spectrum is analyzed at higher injection frequencies with the conversion matrix approach. Very good results have been obtained in comparison with measurements.Spanish project TEC2011-29264-C03-01 for financial support