Experimental study on oscillatory thermocapillary convection

The transition processes from steady flow into oscillatory flow in a liquid bridge of the half floating zone are studied experimentally. Two methods of noncontacted diagnoses are developed to measure the distribution of critical Marangoni numbers described by the onset of the oscillation st the free surface of the liquid bridge.The experimental results obtained for both cases of the upper rod heated and the lower rod heated agree with the prediction by Rayleigh's instability theory.The sensitive relations between the relatively fat or slender liquid bridge and the onset of oscillatory convection are also discussed to reveal the insight of the pressure distribution near the free surface. The experiments have been performed in a small liquid bridge, where the Bond number is much smaller than 1, and the results can be used to simulate the experiment in the microgravity environment.

Testing the Forecasting Performance of Ibex 35 Option-implied Risk-neutral Densities

Published also as: Documento de Trabajo Banco de España 0504/2005.

Estructura de la bolsa española e introducción del mercado de activos derivados sobre el IBEX-35

[ES] La controversia acerca de si la implantación y negociación de activos derivados afecta a la estabilidad de los respectivos mercados de contado perdura desde hace más de dos décadas. En este trabajo abordamos la problemática anterior desde una nueva perspectiva. Concretamente, analizamos el impacto que sobre la estructura del mercado bursátil ha podido tener la introducción de los mercados de activos derivados sobre el IBEX-35. Para ello, definimos e identificamos la estructura del mercado bursátil para el periodo de estudio, y, a continuación, analizamos el efecto que sobre la misma ha tenido la aparición de los nuevos mercados de derivados. Nuestros resultados son consistentes con los de otros autores, ya que si bien no se ha producido un cambio generalizado y substancial en la estructura del mercado bursátil, la introducción de los nuevos mercados sí parece que ha afectado a un número reducido de empresas incluidas en el IBEX-35.

Diário da Constituinte [gravação de vídeo] : [programa n. 725]

Trata da redivisão territorial do Brasil com a criação do estado de Tocantins, a transformação dos territórios de Roraima e Amapá em Estado e as sugestões da criação de novos estados.

Ibex-35 eta IGBM-ren eraginkortasunaren analisia

Artikulu honetan Markowitz-en eredua azaltzen da. Hasieratik Markowitz-en ereduak garrantzia handia izan du teorikoki, garapen eta eratorri ugari eraginez. Gainera, finantza aktiboen merkatuko oreka teoria desberdinen oinarria ere izan dela esan daiteke. Dena den, karteren kudeatzaile eta analisigileen artean praktikan duen erabileran ez da teorian izan duen adina arrakastatsua izan. Egindako ikerketa enpirikoan Markowitz-en ereduak merkatuko erreferentzia karterak (IBEX-35 eta IGBM) gainditzeko gai diren karterak ematen ditu alde batetik. Eta bestetik, IBEX-35 eta IGBM ez dira kartera eraginkorrak eta ez dute merkatuko kartera teorikoaren portaera islatzen.

Measurement of velocity profiles in a rectangular microchannel with aspect ratio α = 0.35

In this work, we measured 14 horizontal velocity profiles along the vertical direction of a rectangular microchannel with aspect ratio alpha = h/w = 0.35 (h is the height of the channel and w is the width of the channel) using microPIV at Re = 1.8 and 3.6. The experimental velocity profiles are compared with the full 3D theoretical solution, and also with a Poiseuille parabolic profile. It is shown that the experimental velocity profiles in the horizontal and vertical planes are in agreement with the theoretical profiles, except for the planes close to the wall. The discrepancies between the experimental data and 3D theoretical results in the center vertical plane are less than 3.6%. But the deviations between experimental data and Poiseuille's results approaches 5%. It indicates that 2D Poiseuille profile is no longer a perfect theoretical approximation since a = 0.35. The experiments also reveal that, very near the hydrophilic wall (z = 0.5-1 mu m), the measured velocities are significantly larger than the theoretical velocity based on the no-slip assumption. A proper discussion on some physical effects influencing the near wall velocity measurement is given.

Near-diffraction-limited, 35.4 W laser-diode end-pumped Nd:YVO4 slab laser operating at 1342 nm

A diode stack end-pumped Nd:YVO4 slab laser at 1342 nm with near-diffraction-limited beam quality by using a hybrid resonator was presented. At a pump power of 139.5 W, laser power of 35.4 W was obtained with a conversion efficiency of 25.4% of the laser diode to laser output. The beam quality M-2 factors were measured to be 1.2 in the unstable direction and 1.3 in the stable direction at the output power of 29 W. (C) 2009 Optical Society of America

Análisis de los rendimientos del IBEX 35

En el presente trabajo se realiza un estudio econométrico para explicar los rendimientos del IBEX 35 de diciembre de 2006 a febrero de 2014 y contrastar si la crisis es un factor determinante sobre ellos en el período citado. Para ello, en primer lugar se realiza un análisis descriptivo de una serie de variables que se considera que van a tener influencia en los rendimientos, tales como: la prima de riesgo, los tipos de interés y el volumen de contratación. Además, se analiza tanto la estacionalidad diaria como mensual. Posteriormente, se especifica y estima un modelo econométrico inicial y tras una serie de contrastes y restricciones se obtiene un modelo ajustado. El resultado final es el previsto antes de realizar la estimación en lo que corresponde a la prima de riesgo, el tipo de interés, y el volumen de contratación, son relevantes para explicar los rendimientos del IBEX 35. Por el contrario, la crisis, que a priori se espera que tenga influencia en los rendimientos del IBEX 35, resulta no tener influencia significativa en éstos.

Análisis de los rendimientos del IBEX 35

En el presente trabajo se realiza un estudio econométrico para explicar los rendimientos del IBEX 35 de diciembre de 2006 a febrero de 2014 y contrastar si la crisis es un factor determinante sobre ellos en el período citado. Para ello, en primer lugar se realiza un análisis descriptivo de una serie de variables que se considera que van a tener influencia en los rendimientos, tales como: la prima de riesgo, los tipos de interés y el volumen de contratación. Además, se analiza tanto la estacionalidad diaria como mensual. Posteriormente, se especifica y estima un modelo econométrico inicial y tras una serie de contrastes y restricciones se obtiene un modelo ajustado. El resultado final es el previsto antes de realizar la estimación en lo que corresponde a la prima de riesgo, el tipo de interés, y el volumen de contratación, son relevantes para explicar los rendimientos del IBEX 35. Por el contrario, la crisis, que a priori se espera que tenga influencia en los rendimientos del IBEX 35, resulta no tener influencia significativa en éstos.

A study of flow conditions near the substratum in an experimental channel [Translation from: Verhandlungen der Internationalen Vereinigung fur Theoretische und Angewandte Limnologie 18, 718-725, 1972]

In a slow flow, on a smooth uniform substratum, a limited bed allows the existence of currents slow enough for benthic invertebrates. These conditions rarely occur naturally. The investigations carried out in this work aimed, on an intermediary scale, to define the influence of irregularities in the substratum on flow near the bottom. The substrata used were made of glass marbles. The investigations were carried out in a transparent channel of 70 cm in length and a rectangular section 10 x 5 cm. The data was analysed to study the general evolution of flow in terms of average speeds and the appearance of the turbulence near the bottom.

The efficiency of plankton in the utilization of the sun radiation [Translation from: Briroda, 12, 29-35, 1948]

The efficiency of utilisation of the sun's radiation by natural communities has not been properly demonstrated with what so far has been obtained of reliable values, and it represents a great interest in many respects. A systematic study of the biotic balance of lakes was done in the course of a succession of summers starting in 1932, extensive material was obtained, which permitted to compute a value fear the utilisation of the sun's radiation by plankton in lakes, and to compare this with corresponding values for marine plankton and terrestrial vegetation.

Optical properties of the organic substances from aqueous humus surface waters. [Translation from: Gidrochim. Mat. 23, 31-35, 1955]

Dissolved organic matter, especially turf and peat, is repsonsible for the colouration of water. The reported study tried to determine the nature of the colouring agent or organic matter by the establishment of a relationship between the intensity of colouration and the total organic matter content. 44 waters from different sources were examined.