A comparison of lyman alpha and HeI lambda 10830 line structure and variations in early-type star atmospheres

Fabry-Perot interferometric profiles for fifty of the early-type stars including supergiants, eclipsing binaries, Bp and Ap stars, Be and shell stars, and variable stars have been obtained. Results for beta Persei (Algol) just before primary and secondary eclipses show strong emission profiles lasting about 0.1 phase. An absorption line was seen during secondary eclipse. Bright supergiant stars (O9-A2) show time-variable, complicated absorption/emission profiles similar to those obtained for the Be/shell stars

A comparison of lyman alpha and He lambda 10830 line structures and variations in early-type star atmospheres

Line profiles were first obtained at maximum velocity separation of the spectroscopic binary Spica (alpha Vir), and then high resolution spectrophotometric images of selected features in the 1.1 micron spectrum of Comet Kohoutek were obtained in order to gain insight into the structures and variations in early-type star atmospheres

New approaches to some methodological problems of meteor science

Several low cost approaches to continuous radioscatter monitoring of the incoming meteor flux are described. Preliminary experiments were attempted using standard time frequency stations WWVH and CHU (on frequencies near 15 MHz) during nighttime hours. Around-the-clock monitoring using the international standard aeronautical beacon frequency of 75 MHz was also attempted. The techniques are simple and can be managed routinely by amateur astronomers with relatively little technical expertise. Time series analysis can now be performed using relatively inexpensive microcomputers. Several algorithmic approaches to the analysis of meteor rates are discussed. Methods of obtaining optimal filter predictions of future meteor flux are also discussed

A study of meteor spectroscopy and physics from earth-orbit: A preliminary survey into ultraviolet meteor spectra

Preliminary data required to extrapolate available meteor physics information (obtained in the photographic, visual and near ultraviolet spectral regions) into the middle and far ultraviolet are presented. Wavelength tables, telluric attenuation factors, meteor rates, and telluric airglow data are summarized in the context of near-earth observation vehicle parameters using moderate to low spectral resolution instrumentation. Considerable attenuation is given to the problem of meteor excitation temperatures since these are required to predict the strength of UV features. Relative line intensities are computed for an assumed chondritic composition. Features of greatest predicted intensities, the major problems in meteor physics, detectability of UV meteor events, complications of spacecraft motion, and UV instrumentation options are summarized

Magnetic Properties of a Two-Dimensional Mixed-Spin System

Using a Langmuir-Blodgett (LB) synthesis method, novel two-dimensional (2D) mixed-spin magnetic systems, in which each magnetic layer is both structurally and magnetically isolated, have been generated. Specifically, a 2D Fe-Ni cyanide-bridged network with a face-centered square grid structure has been magnetically and structurally characterized. The results indicate the presence of ferromagnetic exchange interactions between the Fe$^{3+}$ ($S=1/2$) and Ni$^{2+}$ (S=1) centers.Comment: 2 pages, 3 figs., submitted 23rd International Conference on Low Temperature Physics (LT-23), Aug. 200

A historical analysis of central bank independence in Latin America: the Colombian experience, 1923-2008

This paper explores the relationship between central bank independence and inflation in Latin America, using the experience of Colombia (1923-2008) as a case study. Since its creation, in 1923, Colombia’s central bank has undergone several reforms that have changed its objectives and degree of independence. Between 1923 and 1951, it was private and independent, with a legal commitment to price stability. In 1962, monetary responsibilities were divided between a government-dominated monetary board, in charge of monetary policies, and the central bank, which carried them out. In the early 1990s, the bank recovered its independence and its focus on price stability. Inflation varied substantially during these subperiods. Our analysis suggests that the central bank independence, combined with a commitment to price stability, renders the best results in terms of price stability.Este documento explora la relación entre la independencia del banco central y los niveles de inflación en Latinoamérica, usando como estudio de caso la experiencia de Colombia (1923-2008). Desde su creación en 1923, la independencia y objetivos del banco central en Colombia han sido modificados substancialmente. Entre 1923 y 1951, el banco central fue privado e independiente, y con objetivo principal la estabilidad de precios. En 1962, la responsabilidad monetaria fue dividida entre la Junta Monetaria, encargada del diseño de la política monetaria, y el banco central, que se encargaba de ejecutarla. A principios de los 1990s, el banco recobro´ su independencia y su objetivo fue el control de la inflación. Los niveles de inflación fueron diferentes en estos periodos. El análisis sugiere que la combinación entre un banco central independiente y un objetivo de estabilidad de precios produce los mejores resultados en términos de estabilización de precios

Crystal structure of aluminium cyclononaphosphate, Al3P9O27

Al3O27P9, trigonal, P3̄c1 (No. 165), a = 10.935(2) Å, c = 9.191(2) Å, V = 951.8 Å3, Z = 8, Rgt(F) = 0.037, wRref(F2) = 0.094, T = 293 K

Un análisis histórico de la independencia de la banca central en América Latina: la experiencia colombiana, 1923-2008

Este documento explora la relación entre la independencia del banco central y los niveles de inflación en América Latina, usando como estudio de caso la experiencia de Colombia (1923-2008). Desde su creación en 1923 la independencia y objetivos del banco central en Colombia han sido modificados substancialmente. Entre 1923 y 1951 el banco central fue un ente privado e independiente, teniendo como objetivo principal la estabilidad de precios. En 1962 la responsabilidad monetaria se dividió entre la Junta Monetaria, encargada del diseño de la política monetaria, y el banco central, que la ejecutaba. A principios de los años noventa el banco recobró su independencia y su objetivo pasó a ser el control de la inflación. Los niveles de inflación en estos períodos fueron diferentes. El análisis sugiere que la combinación de un banco central independiente con un objetivo de estabilidad de precios produce mejores resultados en tales términos.Inflación, independencia del banco central, Latinoamérica, Colombia

Magnetodielectric coupling of infrared phonons in single crystal Cu2_{2}OSeO3_{3}

Reflection and transmission as a function of temperature have been measured on a single crystal of the magnetoelectric ferrimagnetic compound Cu$_{2}$OSeO$_{3}$ utilizing light spanning the far infrared to the visible portions of the electromagnetic spectrum. The complex dielectric function and optical properties were obtained via Kramers-Kronig analysis and by fits to a Drude-Lortentz model. The fits of the infrared phonons show a magnetodielectric effect near the transition temperature ($T_{c}\sim 60$~K). Assignments to strong far infrared phonon modes have been made, especially those exhibiting anomalous behavior around the transition temperature