La importancia de la semiótica para una pedagogía de los medios de comunicación

En el presente artículo, el autor realiza un estudio sobre los medios empleados en la comunicación didáctica (lengua, imagen, texto...) desde una perspectiva semiática-pedagógica. En el análisis de esta cuestión se subraya la diferente eficacia didáctica que muestran poseer los distintos medios de codificar los mensajes a enseñar. Cada medio -se argumenta- utiliza signos nítidamente diferenciados; de ahí que sea preciso realizar investigaciones serias, y posteriormente confeccionar taxonomías adecuadas, respecto a la distinta virtualidad de cada medio a la hora de provocar aprendizajes óptimos (facilidad, rapidez, creatividad, ausencia de estrés...). Finalmente, el autor refiere los resultados de una investigación llevada a cabo por él mismo sobre esta temática.In this article the author has carried out a study on the means used in didactic communication (language, picture, text...) from a semiotic-pedagogical perspective. The different didactic efficiency shown by the various means of coding the messages that are to be taught has been underlined in the analysis of this question. It is contended that each medium uses clearly differentiated signs, hence reliable research must be done and subsequently, appropriate taxonomies made with regard to the different potentiality of each medium when the best learning conditions are striven for (ease, speed, creativity, lack of stress...). Finally the author applies the results of research carried out by himself on this subjec

Bessel beam CARS of axially structured samples

We report about a Bessel beam CARS approach for axial profiling of multi-layer structures. This study presents an experimental implementation for the generation of CARS by Bessel beam excitation using only passive optical elements. Furthermore, an analytical expression is provided describing the generated anti-Stokes field by a homogeneous sample. Based on the concept of coherent transfer functions, the underling resolving power of axially structured geometries is investigated. It is found that through the non-linearity of the CARS process in combination with the folded illumination geometry continuous phase-matching is achieved starting from homogeneous samples up to spatial sample frequencies at twice of the pumping electric field wave. The experimental and analytical findings are modeled by the implementation of the Debye Integral and scalar Green function approach. Finally, the goal of reconstructing an axially layered sample is demonstrated on the basis of the numerically simulated modulus and phase of the anti-Stokes far-field radiation pattern

Hydroxyapatite deposition disease of the wrist with intraosseous migration to the lunate bone

Hydroxyapatite deposition disease (HADD) is a mostly uniarticular, self-limiting condition caused by deposition of hydroxyapatite (HA) crystals in tendons or in the peritendinous soft tissues. Commonly, the glenohumeral joint is affected. More rarely, the HA depot can be cause of a carpal tunnel syndrome due to an acute inflammatory reaction and space-occupying soft tissue oedema. We report a case of acute HA depot located at the volar site of the right wrist with affection of the deep flexor tendons and intraosseous migration into the lunate bone in a 50-year-old female. There are two main goals of this case report: First, to remind the diagnosis of HADD as a cause of wrist pain and also of carpal tunnel syndrome, as this entity being often misdiagnosed clinically, and second, to report a rare case of intraosseous migration of HA crystals into the lunate bone

The Physics of Protoplanetesimal Dust Agglomerates. Vi. Erosion of Large Aggregates as a Source of Micrometer-Sized Particles

Observed protoplanetary disks consist of a large amount of micrometer-sized particles. Dullemond and Dominik (2005) pointed out for the first time the difficulty in explaining the strong mid-IR excess of classical T-Tauri stars without any dust-retention mechanisms. Because high relative velocities in between micrometer-sized and macroscopic particles exist in protoplanetary disks, we present experimental results on the erosion of macroscopic agglomerates consisting of micrometer-sized spherical particles via the impact of micrometer-sized particles. We find that after an initial phase, in which an impacting particle erodes up to 10 particles of an agglomerate, the impacting particles compress the agglomerate's surface, which partly passivates the agglomerates against erosion. Due to this effect the erosion halts within our error bars for impact velocities up to ~30 m/s. For larger velocities, the erosion is reduced by an order of magnitude. This outcome is explained and confirmed by a numerical model. In a next step we build an analytical disk model and implement the experimentally found erosive effect. The model shows that erosion is a strong source of micrometer-sized particles in a protoplanetary disk. Finally we use the stationary solution of this model to explain the amount of micrometer-sized particles in observational infrared data of Furlan et al. (2006)

Aussiedlerjugendliche: im Spannungsfeld zwischen deutsch und fremd

In dem vorliegenden Aufsatz stehen deutschstämmige jugendliche Aussiedler im Mittelpunkt mit ihren spezifischen Migrations- und Integrationsproblemen. Viele dieser Jugendlichen sind ohne ausdrücklichen Wunsch in die Bundesrepublik gekommen, da sie in ihrem Land, sei es Rußland, Polen oder Rumänien voll integriert waren. Obwohl die meisten Jugendlichen behaupten, die einheimischen Deutschen seien 'anders' als sie selbst, gibt es wenig Anzeichen für eine mißlungene Anpassung und Entwicklung unter Aussiedlerjugendlichen. Diese unerwartet gelungene Anpassung läßt sich besser verstehen, wenn gezeigt werden kann, daß sich die Jugendlichen tatsächlich schnell, schneller jedenfalls als ihre Eltern, dem 'Skript' des Erwachsenwerdens in Deutschland anpassen. Hierzu zählen die Abfolge und der Zeittakt neuer Anforderungen und Vorrechte beim Übergang von der Kindheit zur Jugend. Dies wird anhand zugrundeliegender Daten bewiesen, die einem interdisziplinären Projekt 'Erfolg und Verlauf der Aneignung durch Ausländer' entstammen, daß von 1990 bis 1993 durchgeführt wurde. (psz