The effects of inadvertent venting introduced by a probe tube in real ear gain

This paper discusses a study to determine if inadvertent venting introduced by a probe-tube significantly alters real ear gain measurements when vented earmolds fit tightly.

Notas sobre la presencia mapuche en la literatura chilena (Crítica)

Mauricio Ostria revisa la manera en que el mapuche es presentado en la literatura chilena. Durante la Colonia, ciertos rasgos de los indios mapuches resaltados por La Araucana, de Alonso de Ercilla (valor, rebeldía, destino épico de resistencia), contribuyeron a configurar la identidad del pueblo chileno. Durante la república, la percepción camina entre la admiración y la conmiseración, y el desprecio por el excluido. En el siglo XX predomina la exclusión, la idea del mapuche como un ser moralmente degradado, sin embargo, poetas como Gabriela Mistral y Pablo Neruda se aproximan con distintos puntos de vista, apartados del desprecio. A fines del siglo XX, la mirada multicultural inicia una literatura que pretende dar voz al mapuche, escritores de esta línea son Violeta Cáceres, Clemente Riedemann, y poetas de origen mapuche, como Jaime Luis Huenún, Leonel Lienlaf, Elicura Chihuailaf («la más reflexiva, la más polémica, la más lúcida de las voces mapuches, la más consciente de la función de resistencia e identidad cultural»), son los que más luchan por una nueva percepción del mapuche que, aun ahora, es visto por la sociedad chilena como héroe, bárbaro o víctima.

Anharmonic force constant calculations

The relationship of the anharmonic force constants in curvilinear internal coordinates to the observed vibration-rotation spectrum of a molecule is reviewed. A simplified method of setting up the required non-linear coordinate transformations is described: this makes use of an / tensor, which is a straightforward generalization of the / matrix used in the customary description of harmonic force constant calculations. General formulae for the / tensor elements, in terms of the familiar L matrix elements, are presented. The use of non-linear symmetry coordinates and redundancies are described. Sample calculations on the water and ammonia molecules are reported.

Inspecting the teaching of singing in the teacher training colleges of England, Wales and Scotland 1883-1899

This paper investigates the links between the teaching of singing, training and inspection during the late Victorian era. It utilises as a primary source the annual inspection reports of the music inspector, Sir John Stainer. More specifically it focuses upon the musical background of the students in the training colleges of England, Wales and Scotland, the methods employed to teach sight singing and voice production, the vocal repertoire and preparation for the teaching of singing in schools. Finally, some comparison is made with the present day and the relationship between the teaching of singing, training and inspection.

Control strategy for Boolean input systems

The purpose of this paper is to design a control law for continuous systems with Boolean inputs allowing the output to track a desired trajectory. Such systems are controlled by items of commutation. This type of systems, with Boolean inputs, has found increasing use in the electric industry. Power supplies include such systems and a power converter represents one of theses systems. For instance, in power electronics the control variable is the switching OFF and ON of components such as thyristors or transistors. In this paper, a method is proposed for the designing of a control law in state space for such systems. This approach is implemented in simulation for the control of an electronic circuit.

Variation in the sensitivity of Callosobruchus (Coleoptera: Bruchidae) acetylcholinesterase to the organophosphate insecticide malaoxon: effect of species, geographical strain and food type

BACKGROUND: Bruchid beetles, Callosobruchus species, are serious pests of economically important grain legumes; their activity in stores is often controlled by use of synthetic insecticides. Esterases are known to be involved in insecticide resistance in insects. However, there is dearth of information on esterase activity in the genus Callosobruchus. In this study we investigated the effect of species, geographical strain and food type on the variation of acetylcholinesterase (AChE) activity and its inhibition by malaoxon (malathion metabolite) using an in vitro spectrophotometric method. RESULT: AChE activity varied significantly among species and strains and also among legume type used for rearing them. Generally irrespective of species, strain or food type, the higher the AChE activity of a population, the higher its inhibition by malaoxon. C. chinensis had the highest AChE activity of the species studied and in the presence of malaoxon it had the lowest remaining AChE activity, while C. rhodesianus retained the highest activity. CONCLUSION: A firsthand knowledge of AChE activity in regional Callosobruchus in line with the prevailing food types should be of utmost importance to grain legume breeders, researchers on plant materials for bruchid control and pesticide manufacturer/applicators for a robust integrated management of these bruchids.