Authors reply to "On uniqueness, transfer and combination of acoustic sources in one-dimensional systems"

The use of electroacoustic analogies suggests that a source of acoustical energy (such as an engine, compressor, blower, turbine, loudspeaker, etc.) can be characterized by an acoustic source pressure ps and internal source impedance Zs, analogous to the open-circuit voltage and internal impedance of an electrical source. The present paper shows analytically that the source characteristics evaluated by means of the indirect methods are independent of the loads selected; that is, the evaluated values of ps and Zs are unique, and that the results of the different methods (including the direct method) are identical. In addition, general relations have been derived here for the transfer of source characteristics from one station to another station across one or more acoustical elements, and also for combining several sources into a single equivalent source. Finally, all the conclusions are extended to the case of a uniformly moving medium, incorporating the convective as well as dissipative effects of the mean flow.

Dislocation Propagation versus Dislocation Nucleation - Authors' Response

No abstract.

Rafael Pividal y Alberto Duhau : aportes y debates en torno a la idea de democracia en el pensamiento político de intelectuales católicos

Resumen: A finales de la década del treinta, especialmente luego de la visita de Maritain en 1936 a la Argentina, surgieron con mucha fuerza una serie de debates dentro de los círculos intelectuales católicos argentinos. Uno de los temas tratados, entre otros, fue el valor de la democracia y, especialmente, su posible justificación como sistema político y su concordancia con las enseñanzas de la Iglesia. Sin embargo, aun aquellos que defendían la democracia no representaban un grupo homogéneo: tanto las fuentes intelectuales a las que recurrían como los fundamentos antropológicos de sus argumentaciones eran diversas. El presente artículo se propone desarrollar la defensa de la democracia que hicieron R. Pividal y A. Duhau, dos de estos intelectuales católicos. Como intentaré demostrar, aun cuando coinciden en resaltar el valor de la democracia y su plena concordancia con el catolicismo, la recurrencia a autores diversos (Maritain y a través de él la oposición a Maurras y Rousseau en un caso y Adam Smith y el Liberalismo escocés en el otro) generan que las argumentaciones de uno y otro difícilmente coincidan en mucho más que en esa positiva valoración que hacen del sistema democrático.

Clasicismo e Ilustración: modelos sin nostalgia

Javier Alonso Aldama, Cirilo García Román e Idoia Mamolar Sánchez (eds)

An annotated bibliography of research on coarse and salmonid fish (excluding salmon and trout) found in fresh water in Scotland

The authors provide an extensive annotated bibliography to a full list of species occurring in Scotland, to highlight what is known about them and to indicate potential areas for further research. The list of references brings together published research papers and numerous unpublished theses and reports, including experimental and laboratory studies conducted in Scotland, although some may not have unique application to the fish fauna in Scottish waters. There has been no attempt to include references that are made incidentally in the general literature intended for naturalists.

A fisheries management plan for the River Tweed in the Scottish Borders

The River Tweed is, in rod-catch terms, the second most important river in Britain for Atlantic salmon, with an annual rod catch of ca.10,000 fish. This article gives an outline of the second edition of the Tweed Fisheries Management Plan, which is defined as "The co-ordination of data collection and analyses with fundamental research into relevant topics to devise management actions that will beneficially affect the future state of fish stocks". Much of the work set down for the present is concerned with setting up recording and measuring systems for fish catches and exploitation rates, and for the operation of monitoring sites for juvenile densities and adult trout and salmon spawning runs. While surveys show the present state of affairs, the collection of records and regular monitoring of sites will mean that in the future, the past will be better known through a longer series of records. Two case histories are described. The first is concerned with setting aims for managing the brown trout of the Tweed and defining the present state of the fishery. The second is an investigation into the spring salmon of the Tweed.