The Use of Parametric and Non Parametric Frontier Methods to Measure the Productive Efficiency in the Industrial Sector. A Comparative Study

Parametric frontier models and non-parametric methods have monopolised the recent literature on productive efficiency measurement. Empirical applications have usually dealt with either one or the other group of techniques. This paper applies a range of both types of approaches to an industrial organisation setup. The joint use can improve the accuracy of both, although some methodological difficulties can arise. The robustness of different methods in ranking productive units allows us to make an comparative analysis of them. Empirical results concern productive and market demand structure, returns-to-scale, and productive inefficiency sources. The techniques are illustrated using data from the US electric power industry.Productive efficiency; parametric frontiers; DEA; industrial sector

Latitudinal and temporal variation of equatorial ionospheric irregularities determined from GPS scintillation observations

International audienceIn this paper we investigate the spatial and temporal distribution of ionospheric irregularities in the South-East Asian longitude sector by analysing the scintillation of GPS signals received at ground based stations. The data used for this work were collected during 1998 to 2002 with our regional network of GPS based scintillation monitors (Thomas et al., 2001). The aim of this analysis is to better understand the morphology and climatology of ionospheric irregularities in our region. Interesting differences between the north and south anomalies are noted when we examine the latitudinal?temporal variation of irregularity activity. We investigate the possible causes of these differences and note that variations in the irregularity seeding mechanism and in the background ionosphere at the two anomalies could be important. Phase screen diffraction theory is used to analyse our scintillation data and we note problems with this theory for ray-paths with large off-zenith angles. The height of the phase screen is another important issue. We discuss the implications for models which rely on phase screen diffraction theory

Detectors for leptonic CP violation at the neutrino factory

Studies carried out in the framework of the International Design Study for the Neutrino Factory (the IDS-NF) show that the sensitivity to the CP violating phase and the last unknown mixing angle θ13 is maximised when two far detectors optimized to detect the sub-leading νe to νμ oscillation are combined. Several technologies are being discussed for these detectors: magnetised iron calorimeters; giant liquid argon TPCs; and totally active scintillating detectors. The IDS-NF baseline option, a compromise between feasibility, cost, and performance, is documented in the Interim Design Report (IDR) that has recently been completed. It consists of two magnetised iron sampling calorimeters, similar to the existing MINOS detector, but with 10-20 times more mass and improved performance. A detector of mass 100 kton is assumed at the intermediate baseline (between 2500 km and 5000 km) and a 50 kton detector at the long baseline (between 7000 km and 8000 km). The other far-detector options, which have better granularity, may be able to detect additional oscillation channels, thus improving the overall performance of the facility. However, these options are likely to be more expensive and require significant R&D

Aqueous suspension processing of multicomponent submicronic Y-TZP/Al2O3/SiC particles for suspension plasma spraying

In order to obtain thermal barrier coatings by Suspension Plasma Spraying (SPS) process with potential new self-healing ability multicomponent submicronic Y-TZP/Al2O3/SiC suspensions were prepared. For this purpose, concentrated aqueous suspensions of individual components, as well as the multicomponent mixture were studied and characterised, in terms of colloidal stability and rheological behaviour to determine the best conditions for processing and preparation of the coatings. In the study, different dispersant contents and sonication times were tested. Subsequently, low concentrated suspensions were prepared to obtain preliminary thermal barrier coatings with the optimised feedstock. Thus, ceramic coatings were deposited by SPS and then characterised in order to assess the microstructure and phase distribution, in particular, the degree of preservation of the sealing agent, SiC, in the final coating as a previous indicator of its self-healing ability

Presión arterial : ¿esfigmomanómetro manual o digital?

El presente es un estudio prospectivo y comparativo entre la medición de la presión arterial obtenida de manera manual con esfigmomanómetro aneroide y la obtenida mediante monitor automático. El desarrollo de la práctica se realizó sobre un grupo de 100 pacientes hospitalizados en el servicio de Neurocirugía y Otorrinolaringología del Consorcio Hospital General de Valencia durante el primer trimestre del año 2007, mediante mediciones secuenciales y efectuadas por el mismo observador con ambos aparatos bien calibrados. Se observó mediante el método de correlación bivariada de Pearson que no existen diferencias estadísticamente significativas entre las presiones tomadas por ambos aparatos determinando así la fiabilidad del aparato automático utilizado en esta sala para el registro de la tensión arterial.This is a prospective and comparative work between arterial pressure obtained through manual measurement with aneroid sphygmomanometer and the arterial pressure obtained through automatic monitor. The practice was carried out in a group of 100 inpatients in the Neurosurgery and Otolaryngology Service in the Consortium of the General Hospital of Valencia during the first term of 2007. The development of this hospital training was made on each individual through sequential measurements and executed by the same observer with both well-calibrated machines. It was observed that through the method of Pearson's bivaried correlation there are not statistically significant differences between the pressures taken by both machines. As regards this fact, both automatic machines of arterial pressure register are [email protected] [email protected]