On the competitive effects of divisionalization

In this paper, we assume that firms can create independent divisions which compete in quantities in a homogeneous good market. Assuming identical firms and constant returns to scale, we prove that the strategic interaction of firms yields Perfect Competition if the number of firms is beyond some critical level. Assuming a fixed cost per firm and an upper bound on the maximum number of divisions, we show that when this upper bound tends to infinity and the fixed cost tends to zero, market equilibrium may yield either Perfect Competition or a Natural Oligopoly.Publicad

Second Best Trade Policies in Cournot Oligopoly

In this paper we study the optimal import policy in an oligopolistic market with a given number of quantity-setting firms. In the absence of fixed costs, we show that if the policy instrument is an import quota, the optimal policy is either free trade or autarky, while if the instrument is a tariff the optimal policy is neither free trade nor autarky. In the case of fixed costs, we show that contrary to the traditional protectionist argument, a restrictive import policy might increase domestic welfare by increasing domestic consumers’ surplus, instead of increasing domestic profits.Publicad

Eclogite facies relics in metabasites from the Sierra de Guadarrama (Spanish Central System): P-T estimations and implications for the Hercynian evolution

Relics of HP-MT eclogitic assemblages related to the first metamorphic stage of the Hercynian orogeny in the Sierra de Guadarrama (Spanish Central System, SCS) are preserved as boudins of pre-Ordovician metabasites enclosed by felsic gneisses. Textures indicate a multi-stage metamorphic history starting in the MT eclogite facies (as deduced from the presence of omphacite and rutile included in garnet) and continuing through medium to low pressure granulite and retrograde amphibolite-greenschist facies. Thermobarometric calculations in the eclogitic paragenesis yield pressures of ~14 kbar for temperatures in the range 725 7758C. Thermobarometry for the subsequent granulitic stage indicates a significant drop in pressure (P < 10 kbar) for similar temperatures of ~7508C. Metabasites vary from gabbro to leucotonalites showing the typical Fe enrichment of the tholeiitic series. Chemical characteristics indicate a derivation from low-pressure crystallization of tholeiitic melts more enriched than typical MORB compositions. Their original location far from continental margins as evidenced by the absence of ophiolitic material in the area and their association with platform sediments suggests that eclogitization was related to intracontinental crustal subduction and thickening. The P-T conditions estimated in the metabasites for the first metamorphic stage are similar to ones deduced for the surrounding metasediments and suggest that the Hercynian crust could have reached a thickness of ~70 80 km, which is more than the double the present thickness

Strain mapping and nanocrystallite size determination by neutron diffraction in an aluminum alloy (AA5083) severely plastically deformed through equal channel angular pressing

Six specimens of an aluminum alloy (AA-5083) extruded by Equal Channel Angular Pressing following two different routes plus a blank sample were examined with a neutron radiation of 1.5448 Å. Macrostrain maps from the (311) reflection were obtained. A clear difference about accumulated macrostrain with the extrusion cycles between the two routes is shown. The diffraction data of annealed specimens did permit to estimate crystallite sizes that range between 89 nm and 115 nm depending on the routes

Consumer Search and Oligopolistic Pricing: An Empirical Investigation

This paper presents an empirical examination of oligopoly pricing and consumer search. The theoretical model allows for sequential and non-sequential search and, using the theoretical restrictions firm and consumer behavior impose on the data, we study the empirical validity of the models. Two equilibria arise: one with costless search and the other with costly search. We find that the costless search equilibrium works well for products with a relatively low value, and, by implication, a small number of sellers. By contrast, the costly search equilibrium explains the observed data in a manner that is consistent with the underlying theoretical model for almost all products (for 86 out of 87!).consumer search, oligopoly, price dispersion, maximum likelihood estimation

Prótesis total de cadera con poropatita: Resultados a 12 años

El trabajo analiza 150 prótesis totales de cadera, con un seguimiento de 12 años. En todos los pacientes se implantaron los componentes de Poropatita fabricados con aleación de Titanio y recubiertos de Poropatita. La edad de los pacientes oscilo entre los 25 y 85 años, con una media de 61 años, y en las revisiones posteriores realizadas, tanto clínica como radiográficamente, se observó una rápida integración de los implantes con áreas de osteoconducción y osteointegración evidentes.We reviewed 150 hip arthroplasties with a follow-up of 12 years. In all patients we used the components made of a titanium alloy with poropatita. The average age of the patients was 85 years (range 25-85 years). The follow-up period showed good clinical outcome, and radiographic parameters disclosed excellent integration of the implants with areas of osteoconduction and osteointegration

Descripción de la flora causante de candidemia en pacientes adultos críticamente enfermos y determinación de los factores de riesgo relacionados en las unidades de cuidado intensivo del Hospital Militar Central en los años 2006 a 2011

El presente proyecto de investigación busca describir la distribución epidemiológica de las diferentes especies de Cándida spp, causantes de candidemia en los pacientes adultos ingresados a las Unidades de Cuidado Intensivo del Hospital Militar Central durante los años 2006 a 2011. Se trata de una investigación de diseño descriptivo analítico retrospectivo a realizarse mediante la revisión y recolección de datos de las historias clínicas de los pacientes con hemocultivos positivos para cándida de acuerdo con los registros de la sección de Microbiología del Laboratorio Clínico del HM

Tratamiento de la pseudoartrosis con P15

La reconstrucción de los defectos óseos, es un problema que se plantea con frecuencia en Cirugía Traumatológica. El objetivo de este trabajo esa evaluar la regeneración ósea en paciente con retardo de consolidación de fracturas de húmero y tibia, utilizando un factor de crecimiento (P15 combinado con Hidroxiapatita) y observar la respuesta osteoinductiva de la regeneración ósea. Se intervinieron quirúrgicamente 12 pacientes, con un seguimiento mínimo de 2 años. Describimos la metodología en cuanto a técnica y control post-operatorio y valoramos el estado clínico, radiológico e histológico. Los resultados fueron muy buenos en 10 casos. El P15 combinado con la Hidroxiapatita, ha permitido ver una respuesta osteoconductiva y osteoinductiva en los defectos óseos, con un futuro presumiblemente prometedor en Cirugía Ortopédica.The reconstruction of bone defects is a problem in the current orthopaedic surgery practice. The object of this study is to evaluate the regeneration in bones defects under the influence of a growth factor (P15 combined with hidroxyapatite), recording the evidence of osteo-inductive activity. Twelve patients with bone defects were operated with a minimal follow up of two years, we detailed the technique and postoperative management of the patients. Clinical, radiology and histology results were assessed, with excellent outcome in 10 cases. The P15 combined with Hidroxyapatite has allowed for a bone conductive and inductive response in bones defects