12,920 research outputs found
A Phillips curve to the Dominican Republic
This paper has provided an empirical evidence to support the existence of the Phillips curve in the case of the Dominican Republic. The Phillips curve is estimated using data over the last forty years and includes a role for supply factors. The most striking feature of the model is the strong relationship between inflation and excess demand.Phillips curve, output gap, unemployment gap
Sparse inversion of Stokes profiles. I. Two-dimensional Milne-Eddington inversions
Inversion codes are numerical tools used for the inference of physical
properties from the observations. Despite their success, the quality of current
spectropolarimetric observations and those expected in the near future presents
a challenge to current inversion codes. The pixel-by-pixel strategy of
inverting spectropolarimetric data that we currently utilize needs to be
surpassed and improved. The inverted physical parameters have to take into
account the spatial correlation that is present in the data and that contains
valuable physical information. We utilize the concept of sparsity or
compressibility to develop an new generation of inversion codes for the Stokes
parameters. The inversion code uses numerical optimization techniques based on
the idea of proximal algorithms to impose sparsity. In so doing, we allow for
the first time to exploit the presence of spatial correlation on the maps of
physical parameters. Sparsity also regularizes the solution by reducing the
number of unknowns. We compare the results of the new inversion code with
pixel-by-pixel inversions, demonstrating the increase in robustness of the
solution. We also show how the method can easily compensate for the effect of
the telescope point spread function, producing solutions with an enhanced
contrast.Comment: 13 pages, 8 figures, accepted for publication in A&
Factores de infraestructura determinantes en el acceso a Internet en México en el período 2000-2008
56 páginas. Maestría en Economía.Un aspecto relevante en el desarrollo social y económico ha sido el acceso a la información y a las tecnologías de la comunicación (TIC), dando énfasis en la disminución de la pobreza. Organismos internacionales como el Banco Mundial centran uno de sus objetivos en la reducción de la pobreza, y es por ello que la incorporación de las TIC ha sido promovida como un mecanismo para: la integración de comunidades rurales que todavía viven aisladas; fomentar el desarrollo entre países y regiones e incrementar el crecimiento de los países dentro de una economía global. Debido a que la penetración de Internet es aún relativamente baja en México a pesar de las varias iniciativas oficiales para abatir la brecha digital, en esta investigación se plantea analizar los efectos de algunos de los principales factores en infraestructura en el acceso a Internet que siguen incidiendo en la persistencia de la brecha digital en el país, como son las inversiones en infraestructura de telecomunicaciones, el precio de acceso a Internet y el efecto del ingreso per-cápita de la población. Estos factores se analizarán en el período 2000 a 2008
El uso de Twitter por parte de actores armados: explicando la Renuencia de Hezbollah
En la tesis de Grado se analiza la naturaleza de la ideología de Hezbollah y como está determina la utilización de Twitter por parte de este grupo terrorista.The aim of the thesis is to analyse the influence of the ideology of a terrorist organization (i.e. Hezbollah) in the usage of a social network e.g. Twitte
Short dynamic fibrils in sunspot chromospheres
Sunspot chromospheres display vigorous oscillatory signature when observed in
chromospheric diagnostics like the strong Ca II lines and H-alpha. New
high-resolution sunspot observations from the Swedish 1-m Solar Telescope show
the ubiquitous presence of small-scale periodic jet-like features that move up
and down. This phenomenon has not been described before. Their typical width is
about 0.3 arcsec and they display clear parabolic trajectories in space-time
diagrams. The maximum extension of the top of the jets is lowest in the umbra,
a few 100 km, and progressively longer further away from the umbra in the
penumbra, with the longest more than 1000 km. These jets resemble dynamic
fibrils found in plage regions but at smaller extensions. LTE inversion of
spectro-polarimetric Ca II 8542 observations enabled for a comparison of the
magnetic field inclination and the properties of these short jets. We find that
the most extended of these jets also have longer periods and tend to be located
in regions with more horizontal magnetic fields. This is a direct observational
confirmation of the mechanism of long-period waves propagating along inclined
magnetic fields into the solar chromosphere. This mechanism was identified
earlier as the driver of dynamic fibrils in plage, part of the mottles in quiet
Sun, and type I spicules at the limb. The sunspot dynamic fibrils that we
report here represent a new class of manifestation of this mechanism. They are
not the same as the transient penumbral and umbral micro-jets reported earlier.Comment: animations of figures can be found at
http://folk.uio.no/rouppe/dfsunspot
Exchange arrangements and economic growth: What relationship is there?
Abstract. This article provides empirical support for the hypothesis that different exchange rate regimes have an impact on economic growth in advanced, emerging and developing countries. The effects of different exchange rate arrangements on economic growth are examined through least squares dummy variable regressions using panel data on 125 countries during the post-Bretton Woods period (1974-1999). Also, this article addresses the issue of measurement errors in the classification of exchange rate regimes by using four different classification schemes. Three de facto and one de jure classifications are used. Consequently, the sensitivity of these results to alternative exchange rate classifications is also tested. The empirical findings indicate that developing countries with fixed regimes tend to have a higher economic growth.Keywords. Exchange rate regimes; Economic growth.JEL. F31; F33; O47
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