Looking for discrete UV absorption features in the early-type eclipsing binaries μ1 Scorpii and AO Cassiopeiae

A search for discrete absorption components in the ultraviolet spectra of the early-type binaries μ1 Scorpii and AO Cassiopeiae has been undertaken by analyzing material secured with the International Ultraviolet Explorer satellite during an exclusively assigned interval of nearly 50 hr. While the spectra of μ1 Sco definitely do not show the presence of such lines, the spectra of AO Cas do confirm them and permit us to draw some conclusions about where they may be formed.Facultad de Ciencias Astronómicas y Geofísica

Looking for discrete UV absorption features in the early-type eclipsing binaries μ1 Scorpii and AO Cassiopeiae

A search for discrete absorption components in the ultraviolet spectra of the early-type binaries μ1 Scorpii and AO Cassiopeiae has been undertaken by analyzing material secured with the International Ultraviolet Explorer satellite during an exclusively assigned interval of nearly 50 hr. While the spectra of μ1 Sco definitely do not show the presence of such lines, the spectra of AO Cas do confirm them and permit us to draw some conclusions about where they may be formed.Facultad de Ciencias Astronómicas y Geofísica

Desarrollo de algoritmos Monte Carlo track – structure para estudiar el efecto de la Interacción de la radiación ionizante con tejido biológico

"Propósito: Extender los códigos Monte Carlo de estructura de track Geant4-DNA y TOPAS-nBio para que sean capaces de recrear y predecir el daño al ADN debido a la radiación ionizante utilizando plásmidos de ADN. Reproducir la respuesta del daño al ADN como función de la concentración de ADN, concentración de DMSO, torcimiento del ADN, y dosis impartida. Metodología: Se llevo a cabo una validación en diferentes etapas de los códigos Monte Carlo Geant4-DNA y TOPAS-nBio para asegurar estos pueden simular de forma exitosa el daño al ADN en plásmidos. En una primera etapa se analizó la respuesta del medio ante diferentes fuentes de radiación (valores G en función de la LET), posteriormente se validaron los algoritmos para su uso a tiempos mayores a los de la química inhomogenea en agua pura (> 1µs), desarrollando los modelos de ADN, finalmente se incorporaron todos los algoritmos implementados en una sola simulación"

Listado taxonómico de organismos que afectan la pitaya amarilla, Selenicereus megalanthus (K. Schum. ex Vaupel) Moran (Cactaceae) en Colombia

A list of organisms associated with yellow pitaya crop, Selenicereus megalanthus (K. Schum. ex Vaupel) Moran in Colombia is provided. The main pests of yellow pitaya in Colombia are the flower-bud fly Dasiops saltans Townsend (Diptera: Lonchaeidae) and Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae). In this study we report 29 organisms affecting yellow pitaya: 4 Classes, i.e., Arachnida (1 sp.), Aves (1 sp.), Gastropoda (2 spp.), Insecta (25 spp.), distributed in 8 Orders and 14 Families.  Se provee una lista de organismos asociados al cultivo de la pitaya amarilla Selenicereus megalanthus (K. Schum. ex Vaupel) Moran en Colombia. Las principales plagas de pitaya amarilla en Colombia son la mosca del botón floral Dasiops saltans Townsend (Diptera: Lonchaeidae) y Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae). En este trabajo se reportan 29 organismos afectando la pitaya amarilla: 4 Clases, i.e., Arachnida (1 sp.), Aves (1 sp.), Gastropoda (2 spp.), Insecta (25 spp.), distribuidos en 8 Órdenes y 14 Familias.  

Listado taxonómico de organismos que afectan la pitaya amarilla, Selenicereus megalanthus (K. Schum. ex Vaupel) Moran (Cactaceae) en Colombia

A list of organisms associated with yellow pitaya crop, Selenicereus megalanthus (K. Schum. ex Vaupel) Moran in Colombia is provided. The main pests of yellow pitaya in Colombia are the flower-bud fly Dasiops saltans Townsend (Diptera: Lonchaeidae) and Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae). In this study we report 29 organisms affecting yellow pitaya: 4 Classes, i.e., Arachnida (1 sp.), Aves (1 sp.), Gastropoda (2 spp.), Insecta (25 spp.), distributed in 8 Orders and 14 Families.  Se provee una lista de organismos asociados al cultivo de la pitaya amarilla Selenicereus megalanthus (K. Schum. ex Vaupel) Moran en Colombia. Las principales plagas de pitaya amarilla en Colombia son la mosca del botón floral Dasiops saltans Townsend (Diptera: Lonchaeidae) y Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae). En este trabajo se reportan 29 organismos afectando la pitaya amarilla: 4 Clases, i.e., Arachnida (1 sp.), Aves (1 sp.), Gastropoda (2 spp.), Insecta (25 spp.), distribuidos en 8 Órdenes y 14 Familias.  

A terahertz-driven non-equilibrium phase transition in a room temperature atomic vapour

There are few demonstrated examples of phase transitions that may be driven directly by terahertz frequency electric fields, and those that are known require field strengths exceeding 1MV cm−1. Here we report a non-equilibrium phase transition driven by a weak (≪1 V cm−1), continuous-wave terahertz electric field. The system consists of room temperature caesium vapour under continuous optical excitation to a high-lying Rydberg state, which is resonantly coupled to a nearby level by the terahertz electric field. We use a simple model to understand the underlying physical behaviour, and we demonstrate two protocols to exploit the phase transition as a narrowband terahertz detector: the first with a fast (20 μs) non-linear response to nano-Watts of incident radiation, and the second with a linearised response and effective noise equivalent power ≤1 pWHz−1/2. The work opens the door to a class of terahertz devices controlled with low-field intensities and operating in a room temperature environment

The regions of formation of C IV resonance lines in β Persei

New IUE images of the close binary β Persei in the phase interval 0.6P-0.8P were analysed in order to confirm or rectify conclusions previously suggested concerning the region where C IV lines are formed. Based on IUE observations taken with high dispersion and small aperture, Sahade and Hernández (1985) concluded that the resonance lines of Si IV would originate in regions near the B8 V component. Instead, the C IV behaviour of velocity-wise in phases 0.65P-0.78P would seem to suggest that this ion would form in a region of the extended envelope that surrounds the whole system. Our recent IUE images, taken with high dispersion and large aperture that cover precisely the phase interval that was not well covered with the first set of observations, show that, in fact, the C IV resonance doublet behaves in the same way as the Si IV. Therefore, Si IV and C IV are formed in the same region of the envelope that surrounds the B8 V component and there is not, indeed, evidence for the existence of more than one high temperature region in the system of Per, such as it had been thought on the basis of former material. On each spectrum the C IV lines are weaker than Si IV. As the available material is not homogeneous, we can not determine variations, with phase in the line profiles and intensities. A new set of observations covering all the orbital cycle ought to be secured to be able to explain the different behaviour of the intensities.Asociación Argentina de Astronomí