4,061 research outputs found
Elections and Governments` Behaviour - An Application to Portuguese Municipalities
Governments have an important role at defining the course of the economy. It is crucial, therefore, to understand their behaviour, their motivations and the factors underlying their policies, once the economy evolution can not be dissociated from the institutional and political background. This paper tests the relation between the economy and politics at the local administration level. Specifically, using a Portuguese municipalities`panel dataset, it tests opportunistics and partisan behaviour of local governments, either on instruments of local economic policy or on local economic outcomes. The main findings are: (i) local governments adopt an opportunistics behaviour, observed both on instruments and outcomes; and (ii) there is no evidence of partisan behaviour whatsoever. These results lead to important issues at light of the Stability and Growth Pact requirements.political business cycles, political economy, government behaviour
Acerca de la epistemología de la matemática
Al parecer, el primero en haber utilizado el término epistemología pudo ser J. F. Ferrier (Institutes of Metaphysics 1854). Sin embargo, en Alemania existía, por lo menos desde 1791, la expresión “Teoría del conocimiento”, que es lo que etimológicamente designa el vocablo forjado con componentes griegos. Epistemología es la rama de la filosofía que estudia el origen, la estructura, los métodos y la validez del conocimiento, dice el Diccionario de Filosofía, de Runes. Una buena descripción de epistemología de la matemática es la de conocimiento del conocimiento matemático, donde desde luego, conocimiento desempeña el papel que le corresponde en dos niveles diferentes. Así, epistemología toma un cariz crítico, que no ha de causar extrañeza dado que la filosofía es ante todo un cuestionamiento de cuanto tenga que ver con las creaciones humanas
Ecuación de Riccati mediante grupos de Lie
La cuestión aquí, prácticamente, es la de qué tanto permite avanzar en el estudio de la ecuación la introducción de los grupos de Lie; además, la de si la consideración de los métodos de solución mediante grupos de Lie permite esclarecer la estructura de las ecuaciones de Riccati que admiten grupos de Lie, o la del conjunto de soluciones. Si se logra determinar para una ecuación, o una familia de ecuaciones, de Riccati un grupo de Lie mediante el cual la ecuación sea invariante, es posible que puedan enunciarse propiedades geométricas de la ecuación, o de la familia de ecuaciones
Ecuaciones de Riccati mediante grupos de Lie
Traducción de una comunicación de Daniel Bernoulli. Funciones elementales de Liouville. Ecuaciones de Bessel reducibles a una ecuación de Riccati
Strong Mixing and Recirculation in the Northwestern Argentine Basin
The Atlantic component of the Meridional Overturning Circulation (AMOC) is a key contributor to the global meridional transport of volume, salt, and heat, and thus plays a central role in global climate. As part of ongoing efforts to monitor the intensity and variability of the AMOC in the South Atlantic, hydrographic sections have been regularly occupied since 2009 near the western boundary along a zonal line at 34.5°S. Here this high-quality, high-resolution data set is analyzed to establish the average hydrographic conditions of the northwestern Argentine Basin and the water mass spatial and temporal variability. The water mass analysis also reveals the pathways of the flow in this region, which are further corroborated by full-depth direct velocity measurements. The repeated hydrographic sections capture an extremely rich vertical structure, characterized by seven distinct water mass layers of northern and southern origin, each with unique property signatures. Almost all of these layers exhibit a sharp zonally banded structure, which is indicative of recirculation cells offshore from the western boundary. The circulation at intermediate levels includes a previously undetected recirculation cell confined very close to the western boundary and superimposed on the classical intermediate water pathway beneath the South Atlantic subtropical gyre. The deep level flow is characterized by the Deep Western Boundary Current (DWBC) and a northward recirculation ~500 km east from the slope.Fil: Valla, Daniel. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; ArgentinaFil: Piola, Alberto Ricardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; ArgentinaFil: Meinen, Christopher S.. Atlantic Oceanographic and Meteorological Laboratory; Estados UnidosFil: Campos, Edmo. Universidade de Sao Paulo; Brasi
Diode laser modules based on laser-machined, multi-layer ceramic substrates with integrated water cooling and micro-optics
This thesis presents a study on the use of low temperature co-fired ceramic (LTCC)
material as a new platform for the packaging of multiple broad area single emitter diode
lasers. This will address the recent trend in the laser industry of combining multiple
laser diodes in a common package to reach the beam brightness and power required for
pumping fibre lasers and for direct-diode industrial applications, such as welding,
cutting, and etching. Packages based on multiple single emitters offer advantages over
those derived from monolithic diode bars such as higher brightness, negligible thermal
crosstalk between neighbouring emitters and protection against cascading failed
emitters. In addition, insulated sub-mounted laser diodes based on telecommunication
standards are preferred to diode bars and stacks because of the degree of assembly
automation, and improved lifetime. At present, lasers are packaged on Cu or CuW
platforms, whose high thermal conductivities allow an efficient passive cooling.
However, as the number of emitters per package increases and improvements in the
laser technology enable higher output power, the passive cooling will become
insufficient. To overcome this problem, a LTCC platform capable of actively removing
the heat generated by the lasers through impingement jet cooling was developed. It was
provided with an internal water manifold capable to impinge water at 0.15 lmin-1 flow
rate on the back surface of each laser with a variation of less than 2 °C in the
temperature between the diodes. The thermal impedance of 2.7°C/W obtained allows
the LTCC structure to cool the latest commercial broad area single emitter diode lasers
which deliver up to 13 W of optical power. Commonly, the emitters are placed in a
“staircase” formation to stack the emitters in the fast-axis, maintaining the brightness of
the diode lasers. However, due to technical difficulties of machining the LTCC structure
with a staircase-shaped face, a novel out-plane beam shaping method was proposed to
obtain an elegant and compact free space combination of the laser beam on board using
inexpensive optics. A compact arrangement was obtained using aligned folding mirrors,
which stacked the beams on top of each other in the fast direction with the minimum
dead space
Random walk in a rotational environment
We define a random walk of a particle in where the space is
rotating. The particle is not glued to the space and will collide with it at
random times, resulting in changes in its velocity and direction. After many
collisions, the random walk starts to have some asymptotic behaviors inherited
from the movement of space. The paper will find the limit movement of the
particle, and explain how the randomness of the random walk gives rise to the
particle asymptotic deterministic movement.Comment: 16 pages, 3 figure
Texto literario y cosmovisión cultural: efecto impregnador de la palabra transmisora y creativa.
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