Hydrodynamics in the wake of a pitching foil

The effect of flexibility on the hydrodynamic loads and on the flow structures generated on a rectangular foil when oscillating in pitch has been studied. Hydrodynamic loads were measured with a 6-axes balance, and the flow structures were investigated by using a Digital Particle Image Velocimetry (DPIV). It is known from nature's fin based propulsion mechanisms, that appendage stiffness plays an important role in their propulsive efficiency. We have studied four different stiffnesses, ranging from completely rigid to highly flexible. Optimal efficiency has been observed for an intermediate case. In this case, a moderately stronger trailing-edge vortex system takes place. A very high level of flexibility of the foil results in a reduction of efficiency.Comment: 4 pages, 4 figures, there are two videos include

The Autonomous Image: Cinematic Narration and Humanism

Blowup, says Armando Prats, is one of the necessary movies. It is a “living expression of the transition into the new narrative domains” in terms of man’s “new vision of himself as a narrative creature in a world whose very essence is cinematic narration.” Prats’ work on the new humanism inherent in postwar filmmaking is a rewarding work with implications for the fields of esthetics and axiology as well as film criticism. In his analyses of four films by three directors—Fellini’s Director’s Notebook and The Clowns, Wertmiller’s Seven Beauties, Antonioni’s Blowup—Prats shows the contrasts between the conventional, word-bound narrative methods of the past and the new narrative in which images are free to display their energies fully, to lead the eye beyond rational concepts of reality and illusion, truth and falsity, good an evil, beauty and ugliness. The autonomous visual event, Prats finds, offers one of the most direct ways of entering into adventures of ideas, particularly in the realm of human values. Movies have revolutionized art as well as thought about art, and inasmuch as art and life converge, they have revolutionized life itself. A. J. Prats is associate professor of English at the University of Kentucky. Helps to explain why so many teachers of religious studies have found film so important, if not essential, for exploring contemporary philosophical and theological issues. —Horizonshttps://uknowledge.uky.edu/upk_film_and_media_studies/1005/thumbnail.jp

On gonihedric loops and quantum gravity

We present an analysis of the gonihedric loop model, a reformulation of the two dimensional gonihedric spin model, using two different techniques. First, the usual regular lattice statistical physics problem is mapped onto a height model and studied analytically. Second, the gravitational version of this loop model is studied via matrix models techniques. Both methods lead to the conclusion that the model has $c_{matter}=0$ for all values of the parameters of the model. In this way it is possible to understand the absence of a continuous transition

Hydrological and erosion response at micro-plot to -catchment scale following forest wildfire, north-central Portugal

Wildfires can have important impacts on hydrological and soil erosion processes, due to the destruction of vegetation cover and changes to soil properties. According to Shakesby and Doerr (2006), these wildfire effects are: i) much better known at small spatial scales (especially erosion plots) than at the scale of catchments; ii) much better studied with respect to overland flow and streamflow (and, then, especially peak discharges) than to soil erosion. Following up on a precursor project studying runoff generation and the associated soil losses from micro-plot to slope-scale in Portuguese eucalypt forests, the EROSFIRE-II project addresses the connectivity of these processes across hillslopes as well as within the channel network. This is done in the Colmeal study area in central Portugal, where the outlet of an entirely burnt catchment of roughly 10 ha was instrumented with a gauging station continuously recording water level and tubidity, and five slopes were each equipped with 4 runoff plots of < 0,5 m2 (“micro-plot”) and 4 slope-scale plots as well as 1 slope-scale sediment fence. Starting one month after the August 2008 wildfire, the plots were monitored at 1- to 2-weekly intervals, depending on the occurrence of rainfall. The gauging station became operational at the end of November 2008, since the in-situ construction of an H-flume required several weeks. A preliminary analysis of the data collected till the end of 2008, focusing on two slopes with contrasting slope lengths as well as the gauging station: revealed clear differences in runoff and erosion between: (i) the micro-plot and slope-scale plots on the same hillslope; (ii) the two slopes; (iii) an initial dry period and a subsequent much wetter period; (iv) the slopes and the catchment-scale, also depending on the sampling period. These results suggest that the different processes govern the hydrological and erosion response at different spatial scales as well as for different periods, with soil water repellency playing a role during the initial post-fire period. The current presentation will review these preliminary results based on the data collected during the first year after the wildfire

INNOVACIÓN COMO CAMBIO INSTITUCIONAL: UNA APROXIMACIÓN DESDE LAS TEORÍAS DE LA COMPLEJIDAD

Uno de los temas más controvertidos dentro de la literatura sobre gestión de la innovación es el grado en que estos procesos son controlables y planificables. Esta literatura ha evolucionado desde una posición racional dentro de la cual los procesos de innovación son el resultado de decisiones racionales, intencionadas y debidamente planificadas, a una posición más evolutiva en la cual si bien no es posible controlar y gestionar el proceso directamente, si que lo es controlar el las condiciones del contexto organizativo de la innovación con objeto de incrementar el éxito del proceso. En este artículo, analizamos el proceso de innovación desde un nuevo paradigma que va más allá de los anteriores y que se fundamenta en los postulados de las teorías de la complejidad y en la asimilación de los procesos de innovación a los procesos de cambio institucional. Desde esta nueva perspectiva, se deduce que los procesos de innovación y el cambio institucional consiguiente tienen una base pragmática y, en consecuencia, el potencial para la planificación y control de los procesos de innovación se ve altamente limitado

Influence of general convective motions on the exterior of isolated rotating bodies in equilibrium

The problem of describing isolated rotating bodies in equilibrium in General Relativity has so far been treated under the assumption of the circularity condition in the interior of the body. For a fluid without energy flux, this condition implies that the fluid flow moves only along the angular direction, i.e. there is no convection. Using this simplification, some recent studies have provided us with uniqueness and existence results for asymptotically flat vacuum exterior fields given the interior sources. Here, the generalisation of the problem to include general sources is studied. It is proven that the convective motions have no direct influence on the exterior field, and hence, that the aforementioned results on uniqueness and existence of exterior fields apply equally in the general case.Comment: 8 pages, LaTex, uses iopart style files. To appear in Class. Quatum Gra

Artritis séptica de hombro: caso clínico en varón joven

La artritis séptica de hombro en adultos es poco frecuente, representando aproximadamente un 3% de todas las artritis sépticas. Con frecuencia se diagnostica tardíamente con lo que se compromete el resultado final. Se presenta el caso de un varón de 15 años de edad que acudió a urgencias hospitalarias por dolor intenso e impotencia funcional del hombro izquierdo, tumefacción y aumento de la temperatura local. Como antecedente refería haber realizado un esfuerzo físico unos días antes. Pese a la inespecificidad de los resultados de las pruebas realizadas en urgencias, clínicamente se sospechó una artritis séptica de hombro, confirmándose el diagnóstico mediante RM y punción, y realizándose tratamiento antibiótico precoz y limpieza artroscópica. El paciente evolucionó satisfactoriamente con recuperación completa. A propósito del mismo revisamos las claves para el diagnóstico y tratamiento actuales de esta patología.Septic arthritis of the shoulder in adults is an unusual disease (only 3 % of all septic arthritis). Diagnosis is usually made too late, thus interfering in the last result. We report a clinical case in a fifteen years old man who went to the emergency room relating a great pain and difficult movement in his left shoulder, which was swelling and warm. He had made an effort some days before. The initial studies results in the emergency room were normal but clinically we suspected a septic arthritis of the glenohumeral joint. This diagnosis was ratified with RM and punture of the joint. We carried out a treatment consisting of early antibiotic therapy and arthroscopic cleaning. The patient goes on satisfactorily with complete recovery. Thereafter we review the present diagnosis and treatment of this entity