Return to Dollar, Generalized Distance Function and the Fisher Productivity Index

Exploring the duality between a return to dollar definition of profit and the generalized distance function we establish the relationship between the Laspeyres, Paasche and Fisher productivity indexes and their alternative Malmquist indexes counterparts. By proceeding this way, we propose a consistent decomposition of these productivity indexes into two mutually exclusive components. A technical component represented by the Malmquist index and an economical component which can be identified with the contribution that allocative criteria make to productivity change. With regard to the Fisher index, we indicate how researchers can further decompose the Malmquist technical component rendering explicit the sources of productivity change. We also show how the proposed model can be implemented by means of Data Envelopment Analysis techniques, and illustrate the empirical process with an example data set.Generalized Distance Function; Return to Dollar; Fisher and Malmquist Productivity Indexes

Urban patterns, population density and optimal city dimension: The case of public infrastructure

Determination of the optimal city size underlies the economic rationality of infrastructure provision by local governments. We investigate the existence of decreasing average costs resulting from economies of scale, associated with larger urban dimensions in terms of population and housing, and economies of density, brought about by reductions in urban dispersion, and calculate optimal population densities when providing basic infrastructure. The methodology relies on novel definitions of scale and density economies and their estimation by way of flexible translog cost functions, extensively applied in the literature dealing with the provision of services—i.e., utilities, but extended here to their supporting infrastructure. Our results unveil the existence of latent economies of scale and density resulting in a cost excess in the provision of infrastructure due to the effect of urban sprawl that translates into suboptimal city sizes. Based on these findings several policy guidelines rationalizing urban development are suggested. The model is illustrated using Spanish statistical data collected from the nationwide local infrastructure and equipment survey, and prices from a new database that uses engineering cost benchmarks.Urban patterns; Optimal urban density; Scale and density economies; Translog cost function.

Return to dollar, generalized distance function and the fisher productivity index

Exploring the duality between a return to dollar definition of profit and the generalized distance function we establish the relationship between the Laspeyres, Paasche and Fisher productivity indexes and their alternative Malmquist indexes counterparts. By proceeding this way, we propose a consistent decomposition of these productivity indexes into two mutually exclusive components. A technical component represented by the Malmquist index and an economical component which can be identified with the contribution that allocative criteria make to productivity change. With regard to the Fisher index, we indicate how researchers can further decompose the Malmquist technical component rendering explicit the sources of productivity change. We also show how the proposed model can be implemented by means of Data Envelopment Analysis techniques, and illustrate the empirical process with an example data set

Malmquist productivity index decompositions: a unifying framework

In two widely cited but unpublished working papers, Simar and Wilson (1998) and Zofío and Lovell (1998) proposed an alternative decomposition of the Malmquist Productivity Index, which retained what seemed to be the strongholds of previous proposals with regard to the contribution of technological and efficiency change to productivity change. Namely, a technical change term with regard to the best practice (VRS) technology which is to be found in Ray and Desli (1997) and a scale efficiency change term that illustrates a firm’s situation with regard to optimal scale (benchmark technology), Färe, Grosskopf, Norris and Zhang (1994). Attaining this objective required the introduction of an additional term in the Malmquist Productivity Index decomposition, which would reflect the scale bias of technical change. It is our objective to provide economic rationale for this term within a theory of production context, the existing decompositions and recent articles that further elaborate on this issue. The ideas are illustrated using productivity trends in 17 OECD countrie

Problems and solutions in calculating quality-adjusted life years (QALYs)

The quality-adjusted life-year (QALY) is a measure of the value of health outcomes. Since health is a function of length of life and quality of life, the QALY was developed as an attempt to combine the value of these attributes into a single index number. The QALY calculation is simple: the change in utility value induced by the treatment is multiplied by the duration of the treatment effect to provide the number of QALYs gained. QALYs can then be incorporated with medical costs to arrive at a final common denominator of cost/QALY. This parameter can be used to compare the cost-effectiveness of any treatment. Nevertheless, QALYs have been criticised on technical and ethical grounds. A salient problem relies on the numerical nature of its constituent parts. The appropriateness of the QALY arithmetical operation is compromised by the essence of the utility scale: while life-years are expressed in a ratio scale with a true zero, the utility is an interval scale where 0 is an arbitrary value for death. In order to be able to obtain coherent results, both scales would have to be expressed in the same units of measurement. The different nature of these two factors jeopardises the meaning and interpretation of QALYs. A simple general linear transformation of the utility scale suffices to demonstrate that the results of the multiplication are not invariant. Mathematically, the solution to these limitations happens through an alternative calculation of QALYs by means of operations with complex numbers rooted in the well known Pythagorean theorem. Through a series of examples, the new calculation arithmetic is introduced and discussed

La protección del niño en los conflictos armados por el Derecho Internacional Humanitario. Los niños soldados

El Derecho Internacional Humanitario determina una protección especial para personas particularmente vulnerables como los niños en los conflictos armados. Se protege al niño como miembro de la población civil y se le otorga una protección especial en los conflictos armados internacionales e internos. Se prohíbe reclutarlos, alistarlos y que participen directamente en las hostilidades y, conforme al Protocolo Facultativo a la Convención de los Derechos del Niño de 2000, se eleva la edad hasta los 18 años. La Corte Penal Internacional se encuentra investigando a presuntos responsables de crímenes de guerra cometidos contra los niños en África. Se tipificaron en el Código Penal español de 1995 los «Delitos contra las personas y bienes protegidos en caso de conflicto armado» y por Ley Orgánica 5/2010 se ha mejorado la protección penal de la infancia, incriminando el reclutamiento y participación directa de los niños menores de 18 años en los conflictos armados

La represión del crimen internacional de piratería; una laguna imperdonable de nuestro Código Penal y, ¿por qué no?, un crimen de la competencia de la Corte Penal Internacional

La represión del crimen internacional de piratería presenta arduos problemas relativos a la definición de la piratería y al enjuiciamiento de este delito por los tribunales nacionales (en particular en España) e internacionales. La participación española en la operación naval Atalanta de la UE para luchar contra la piratería en las aguas próximas a Somalia ha puesto de relieve los problemas jurídico-penales e internacionales que plantea la represión del crimen de piratería, y en particular la dificultad de juzgar a los piratas capturados por un buque de guerra cuando no está tipificado el delito en la ley penal española. En este ARI se estudia la definición de piratería en relación con el lugar de ejecución y su comisión en la Zona Económica Exclusiva, diferenciándola del “robo a mano armada”, se da cuenta de la laguna existente en el vigente Código Penal español, de los problemas para la aplicación de la Convención de Roma de 1988 y del contenido de diversas Resoluciones del Consejo de Seguridad de las Naciones Unidas. Asimismo, se pone de manifiesto la indeterminación jurisdiccional para el enjuiciamiento estatal de la piratería y se proponen diversas soluciones normativas, inclinándose el autor por la modificación del Estatuto de Roma de la Corte Penal Internacional para incorporar a la piratería entre los crímenes de la competencia de la Corte

Introduction to Projections of Spanish Jesuit Scholasticism on British Thought. New Horizons in Politics, Law and Rights.

pre-print587 K

Laser Ultrasound Inspection Based on Wavelet Transform and Data Clustering for Defect Estimation in Metallic Samples

Laser-generated ultrasound is a modern non-destructive testing technique. It has been investigated over recent years as an alternative to classical ultrasonic methods, mainly in industrial maintenance and quality control procedures. In this study, the detection and reconstruction of internal defects in a metallic sample is performed by means of a time-frequency analysis of ultrasonic waves generated by a laser-induced thermal mechanism. In the proposed methodology, we used wavelet transform due to its multi-resolution time frequency characteristics. In order to isolate and estimate the corresponding time of flight of eventual ultrasonic echoes related to internal defects, a density-based spatial clustering was applied to the resulting time frequency maps. Using the laser scan beam’s position, the ultrasonic transducer’s location and the echoes’ arrival times were determined, the estimation of the defect’s position was carried out afterwards. Finally, clustering algorithms were applied to the resulting geometric solutions from the set of the laser scan points which was proposed to obtain a two-dimensional projection of the defect outline over the scan plane. The study demonstrates that the proposed method of wavelet transform ultrasonic imaging can be effectively applied to detect and size internal defects without any reference information, which represents a valuable outcome for various applications in the industry. View Full-TextPeer ReviewedPostprint (published version