2,290 research outputs found
ASSESSING ADMINISTRATION CHARGES FOR THE AFFILIATE IN INDIVIDUAL ACCOUNT SYSTEMS
In any pension system based on capitalization, affiliates have to cover certain explicit costs which in a pay-as-you-go system would be implicit. In this paper we set out a model based on Whitehouse (2000) and Diamond (1999) to enable the explicit costs borne by the affiliate both during his working life and his retirement period to be assessed. It also shows the relationships between the different ways of measuring the costs that make up the total price finally paid by the contributors. Included in the model is the notable effect that some factors -such as gaps in contribution profiles, account transfers and changes in salary profiles- have on projecting the costs borne by the affiliates. Finally we carry out an international comparison of administration costs from the point of view of the affiliate, focusing special attention on the countries of Latin America and Spain. This has a double objective: 1.- To test the validity of criticisms made by some researchers as to whether the new capitalization systems introduced in Latin America are too expensive to run for the affiliates. 2.- To serve as a reference for the individual pension scheme system in Spain. En un sistema de pensiones basado en la capitalización los afiliados deben hacer frentea unos costes explícitos que en el sistema de reparto son implícitos. En este trabajo sedesarrolla un modelo, basado en Whitehouse (2000) y Diamond (1999), que permite evaluarlas comisiones explícitas que soporta el afiliado, tanto durante la vida laboral como durante laetapa de jubilación y que, además, muestra la relación entre las diferentes medidas de loscostes que integran el precio total que finalmente pagan los cotizantes. En el modelo seintroduce el efecto de algunos aspectos que tienen una repercusión muy importante en laproyección de los costes que soportan los afiliados: ¿vacíos¿ en los perfiles de aportación,efecto de los traspasos de fondos y cambio en los perfiles de salarios. Por último, se realizauna comparación internacional de los costes de administración desde la óptica de los afiliadoscon un doble objetivo:1.-Contrastar la validez de la crítica realizada por algunos investigadores a los nuevossistemas de capitalización individual implantados en América Latina, en el sentido de que sonexcesivamente caros de gestionar para los afiliados.2.-Servir de referencia para el sistema de planes de pensiones individuales en España.Capitalización, Costes de Administración, Fondo de pensiones, América Latina. Capitalization, Administration Costs, Pension Funds, Latin America
Effect of metal micro-structuring on the mechanical behavior of polymer–metal laser T-joints
AbstractThe metal was locally structured by pulsed laser radiation producing microscopic patterns on its surface. In a second step the opposite side of the micro-structured metal was irradiated by a continuous wave (CW) fiber laser to achieve the mechanical interlock between the two materials. A tight relationship between the microstructure parameters and pull-out test performance was observed. The greatest strength was achieved when the distance between subsequent grooves was minimized. The T-joint mechanical performance did not reveal any significant dependence on the considered range of joining areas. The morphological and topographical features of the detached surfaces showed that the micro-structured grooves were completely filled during the laser conductive joining process. Different alignment angles of patterns produced different failure modes although there was no evidence of an additional mechanical interlock
Importance of Treatment Process on the Analysis of Penicillins in Milk Samples by Capillary Electrophoresis
Laser transmission welding of Acrylonitrile-Butadiene-Styrene (ABS) using a tailored high power diode-laser optical fiber coupled system
Laser transmission welding (LTW) of polymers is a direct bonding technique which is already used in different
industrial applications sectors such as automobile, microfluidic, electronic and biomedicine. This technique offers several advantages over conventional methods, especially when a local deposition of energy and minimum thermal distortions are required. In LTW one of the polymeric materials needs to be transparent to the laser wavelength and the second part needs to be designed to be absorbed in IR spectrum. This report presents a study of laser weldability of ABS (acrylonitrile/butadiene/styrene) filled with two different concentrations of carbon nanotubes (0.01% and 0.05% CNTs). These additives are used as infrared absorbing components in the laser welding process, affecting the thermal and optical properties of the material and, hence, the final quality of the weld seam. A tailored laser system has been designed to obtain high quality weld seams with widths between 0.4 and 1.0mm. It consists of two diode laser bars (50W per bar) coupled into an optical fiber using a non-imaging solution: equalization of the beam quality factor (M2 ) in the slow and fast axes by a pair of micro step-mirrors. The beam quality factor has been analyzed at different laser powers with the aim to guarantee a coupling efficiency to the multimode optical fiber. The power scaling is carried out by means of multiplexing polarization technique. The analysis of energy balance and beam quality is performed in two linked steps: first by means ray tracing simulations (ZEMAX® ) and second, by validation. Quality of the weld seams is analyzed in terms of the process parameters (welding speed, laser power and clamping
pressure) by visual and optical microscope inspections. The optimum laser power range for three different welding speeds is determinate meanwhile the clamping pressure is held constant. Additionally, the corresponding mechanical shear tests were carried out to analyze the mechanical properties of the weld seams. This work provides a detailed study concerning the effect of the material microstructure and laser beam quality on the final weld formation and surface integrity
Bird roadkill occurences in Aragon, Spain
The increase in road networks and vehicular traffic has posed a major threat to vertebrates over the last century. Although it is difficult to determine the annual number of avian–vehicle collisions, 2 to 9 million roadkills have been estimated for Europe, with numbers varying from country to country. Few studies have been conducted at a national or regional level in Spain. In this study we used data from La Alfranca Wildlife Rehabilitation Centre database to determine location, season and incidence of avian–vehicle collisions in the autonomous county of Aragon (Spain). A total of 643 wild birds representing 71 species were killed on roads between 2012 and 2014. Nine of these species have a high incidence of avian–vehicle collisions, four a moderate incidence, and 57 a low incidence. The species with the highest incidence was the griffon vulture (120 individuals). Spatial distribution of avian–vehicle collisions was heterogeneous, and the incidence was highest in July, August and September. We identified 41 reas of high roadkill occurrence, using a number of roadkills per km index (RI): 28 in the province of Zaragoza, 9 in Huesca and 4 in Teruel. Management strategies are proposed to reduce this threat on wild birds
Modelo de aprovechamiento de aguas lluvias en zonas de pobreza extrema
Las ventajas de captar agua lluvia en un entorno natural son: agua extremadamente limpia en comparación con otras fuentes de agua dulce disponibles, recurso esencialmente gratuito e independiente de empresas suministradoras habituales y que requiere de infraestructura sencilla para su captación, almacenamiento y distribución. El sistema de captación del agua lluvia permite almacenarla y posteriormente someter a tratamiento la que se utilizará para el consumo humano. A este sistema se le denomina CATDALL, que fue el prototipo resultado final del desarrollo del proyecto, gracias al apoyo del Fondo para la Investigación en Educación Superior (FIES) y la Universidad Tecnológica de El Salvador (UTEC). El prototipo puede ser replicable en otros centros escolares, que presenten escasez de agua bajo las circunstancias que fueren o como simple alternativa de ahorro aprovechando un recurso natural que es gratuito.Investigación desarrollada bajo el convenio FIES-UTEC, 2008-2009Universidad Tecnológica de El Salvado
Buccodental health and oral mucositis : clinical study in patients with hematological diseases
El objetivo del presente trabajo fue valorar si un buen estado buco-dental (valorado mediante índices dento-gingivales), se asociaba a una menor incidencia y gravedad de mucositis oral en pacientes con enfermedades hematológicas que iban a recibir tratamiento con quimioterapia o un trasplante de médula ósea. Diseño del estudio: El estudio se llevó a cabo en 97 pacientes ingresados en el Servicio de Hematología del Hospital Duran y Reynals en Barcelona en los años 2002-2003. Estos pacientes recibían tratamiento con quimioterapia o bien el acondicionamiento previo a un trasplante de médula ósea. Se realizó un estudio descriptivo analizando un índice dental, dos índices gingivales y la higiene oral y su relación con la aparición de mucositis. Resultados: Los pacientes que durante la quimioterapia mostraron valores elevados del índice de placa (IP) y gingival (IG) presentaron un mayor porcentaje de mucositis (77.4% y 65.7% respectivamente) frente a los que tenían poca placa o ésta no era visible. En el caso del IP las diferentas fueron estadísticamente significativas (p=0.015). Asimismo los pacientes que cepillaban los dientes 3veces/día sólo presentaron mucositis en un 26.7% de los casos, frente a los que no cepillaban o lo hacían una vez al día (65.9% y 68.4%), siendo estas diferencias también estadísticamente significativas (p=0.013). El ICAO mostró resultados similares en los pacientes con o sin mucositis (7.59 y 7.03 respectivamente). Conclusiones: En nuestro trabajo, un buen estado gingival así como una buena higiene oral durante la quimiorradioterapia, se asocian a una menor incidencia y gravedad de mucositis
Histopathological Analogies in Chronic Pulmonary Lesions between Cattle and Humans: Basis for an Alternative Animal Model
Most of the natural cases of pneumonia in feedlot cattle are characterized by a longer clinical course due to chronic lung lesions. Microscopically, these lesions include interstitial fibroplasia, bronchitis, bronchiectasis, bronchiolitis obliterans, and epithelial metaplasia of the airways. Herein, the aim was to review, under a medical perspective, the pathologic mechanisms operating in these chronic pneumonic lesions in calves. Based on the similarities of these changes to those reported in bronchiolitis obliterans/organising pneumonia (BO/OP) and chronic obstructive pulmonary disease (COPD) in human beings, calves are proposed as an alternative animal model
Front microrheology of the non-Newtonian behavior of blood: scaling theory of erythrocyte aggregation by aging
We introduce a new framework to study the non-Newtonian behaviour of fluids at the microscale based on the analysis of front advancement. We apply this methodology to study the non-linear rheology of blood in microchannels. We carry out experiments in which the non-linear viscosity of blood samples is quantified at different haematocrits and ages. Under these conditions, blood exhibits a power-law dependence on the shear rate. In order to analyse our experimental data, we put forward a scaling theory which allows us to define an adhesion scaling number. This theory yields a scaling behaviour of the viscosity expressed as a function of the adhesion capillary number. By applying this scaling theory to samples of different ages, we are able to quantify how the characteristic adhesion energy varies as time progresses. This connection between microscopic and mesoscopic properties allows us to estimate quantitatively the change in the cell-cell adhesion energies as the sample age
How old are giant squids? First approach to aging Architeuthis beaks
The giant squid Architeuthis dux Steenstrup, 1857 is one of the largest and most enigmatic marine species. Its age estimation remains controversial with many estimates of maximum age ranging from 1 to 14 yrs. Successful results regarding the study of aging in cephalopod beaks for some octopod and oegopsid squids support using these structures for age estimation. We analyzed the beaks of 10 individuals, caught between 1995 and 2006, with reconstructed dorsal mantle lengths (DMLs) between 823 and 1418 mm. The beaks were measured and weighed, and their microstructure was analyzed in three ways: (1) in the rostrum area [rostrum sagittal sections (RSS)] for both upper and lower jaws, and the (2) inner lateral wall surfaces (LWS) and (3) inner crest surfaces (CS) for upper jaws. A constant sequence of increments was observed along the RSS, indicating that the use of lower jaws is more feasible due to the higher erosion and tighter packing of increments of upper jaws. The statolith of one individual was analyzed, resulting in 520 increments (579 increments from RSS of its lower jaw). Assuming daily deposition, the age estimations in RSS between 411 and 674 d suggest rapid growth of A. dux, averaging 1.97 mm DML d–1 (SD 0.45). When maximum ages were estimated by applying these results to the largest measured specimens in the literature (e.g., 2400 mm DML), an age of approximately 3 yrs was obtained. Analysis over a greater size range of individuals would allow more accurate age estimations of this emblematic squid.En prensa1,14
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