Abnormal photosensitivity effects and the formation of type IA FBGs

We report the abnormal photosensitivity effects leading to the formation of Type IA FBGs. We show the rate at which these gratings form is related to the intensity of the UV inscription laser. We report the first measurement of the reflection along the gratings’ length.

Highly sensitive type IA fiber Bragg gratings as sensors in radiation environments

Type IA fiber gratings have unusual physical properties compared with other grating types. We compare with performance characteristics of Type IA and Type I Bragg gratings exposed to the effects of Co60 gamma-irradiation. A Bragg peak shift of 190 pm was observed for Type IA gratings written in Fibercore PS-1250/1500 photosensitive fiber at a radiation dose of 116 kGy. This is the largest wavelength shift recorded to date under radiation exposure. The Type IA and Type I gratings show different kinetics under radiation and during post-radiation annealing; this can be exploited for the design of a grating based dosimetry system. © 2012 SPIE.

A Minimal History of the Cuban Revolution (Historia mínima de Ia Revolución Cubana), Book Presentation by Author Rafael Rojas

This flyer promotes the event "A Minimal History of the Cuban Revolution (Historia mínima de Ia Revolución Cubana), Book Presentation by Author Rafael Rojas", part at the SIPA at Books & Books series. This event held at Books & Books in Coral Gables.

Santiago de Cuba en Ia música, Lecture by Emilio Cueto

This flyer promotes the event "Santiago de Cuba en Ia música, Lecture by Emilio Cueto" cosponsored by FIU's Cuban Research Institute, Latin American and Caribbean Center, and the FIU Libraries.

Type Ia supernovae from violent mergers of carbon-oxygen white dwarfs: polarization signatures

The violent merger of two carbon-oxygen white dwarfs has been proposed as a viable progenitor for some Type Ia supernovae. However, it has been argued that the strong ejecta asymmetries produced by this model might be inconsistent with the low degree of polarization typically observed in Type Ia supernova explosions. Here, we test this claim by carrying out a spectropolarimetric analysis for the model proposed by Pakmor et al. for an explosion triggered during the merger of a 1.1 and 0.9 M⊙ carbon-oxygen white dwarf binary system. Owing to the asymmetries of the ejecta, the polarization signal varies significantly with viewing angle. We find that polarization levels for observers in the equatorial plane are modest (≲1 per cent) and show clear evidence for a dominant axis, as a consequence of the ejecta symmetry about the orbital plane. In contrast, orientations out of the plane are associated with higher degrees of polarization and departures from a dominant axis. While the particular model studied here gives a good match to highly polarized events such as SN 2004dt, it has difficulties in reproducing the low polarization levels commonly observed in normal Type Ia supernovae. Specifically, we find that significant asymmetries in the element distribution result in a wealth of strong polarization features that are not observed in the majority of currently available spectropolarimetric data of Type Ia supernovae. Future studies will map out the parameter space of the merger scenario to investigate if alternative models can provide better agreement with observations.

The peculiar Type Ia supernova iPTF14atg: Chandrasekhar-mass explosion or violent merger?

iPTF14atg, a subluminous peculiar Type Ia supernova (SN Ia) similar to SN 2002es, is the first SN Ia for which a strong UV flash was observed in the early-time light curves. This has been interpreted as evidence for a single-degenerate (SD) progenitor system, where such a signal is expected from interactions between the SN ejecta and the non-degenerate companion star. Here, we compare synthetic observables of multidimensional state-of-the-art explosion models for different progenitor scenarios to the light curves and spectra of iPTF14atg. From our models, we have difficulties explaining the spectral evolution of iPTF14atg within the SD progenitor channel. In contrast, we find that a violent merger of two carbon-oxygen white dwarfs with 0.9 and 0.76 M⊙, respectively, provides an excellent match to the spectral evolution of iPTF14atg from 10 d before to several weeks after maximum light. Our merger model does not naturally explain the initial UV flash of iPTF14atg. We discuss several possibilities like interactions of the SN ejecta with the circumstellar medium and surface radioactivity from an He-ignited merger that may be able to account for the early UV emission in violent merger models.

Searching for swept-up hydrogen and helium in the late-time spectra of 11 nearby Type Ia supernovae

The direct detection of a stellar system that explodes as a Type Ia supernova (SN Ia) has not yet been successful. Various indirect methods have been used to investigate SN Ia progenitor systems but none have produced conclusive results. A prediction of single-degenerate models is that H- (or He-) rich material from the envelope of the companion star should be swept up by the SN ejecta in the explosion. Seven SNe Ia have been analysed to date looking for signs of H-rich material in their late-time spectra and none were detected. We present results from new late-time spectra of 11 SNe Ia obtained at the Very Large Telescope using XShooter and FORS2. We present the tentative detection of Hα emission for SN 2013ct, corresponding to ∼0.007 M_⊙ of stripped/ablated companion star material (under the assumptions of the spectral modelling). This mass is significantly lower than expected for single-degenerate scenarios, suggesting that >0.1 M_⊙ of H-rich is present but not observed. We do not detect Hα emission in the other 10 SNe Ia. This brings the total sample of normal SNe Ia with non-detections (<0.001–0.058 M_⊙) of H-rich material to 17 events. The simplest explanation for these non-detections is that these objects did not result from the explosion of a CO white dwarf accreting matter from a H-rich companion star via Roche lobe overflow or symbiotic channels. However, further spectral modelling is needed to confirm this. We also find no evidence of He-emission features, but models with He-rich companion stars are not available to place mass limits.

Predicting polarization signatures for double-detonation and delayed-detonation models of Type Ia supernovae

Calculations of synthetic spectropolarimetry are one means to test multidimensional explosion models for Type Ia supernovae. In a recent paper, we demonstrated that the violent merger of a 1.1 and 0.9 M⊙ white dwarf binary system is too asymmetric to explain the low polarization levels commonly observed in normal Type Ia supernovae. Here, we present polarization simulations for two alternative scenarios: the sub-Chandrasekhar mass double-detonation and the Chandrasekhar mass delayed-detonation model. Specifically, we study a 2D double-detonation model and a 3D delayed-detonation model, and calculate polarization spectra for multiple observer orientations in both cases. We find modest polarization levels (<1 per cent) for both explosion models. Polarization in the continuum peaks at ∼0.1–0.3 per cent and decreases after maximum light, in excellent agreement with spectropolarimetric data of normal Type Ia supernovae. Higher degrees of polarization are found across individual spectral lines. In particular, the synthetic Si II λ6355 profiles are polarized at levels that match remarkably well the values observed in normal Type Ia supernovae, while the low degrees of polarization predicted across the O I λ7774 region are consistent with the non-detection of this feature in current data. We conclude that our models can reproduce many of the characteristics of both flux and polarization spectra for well-studied Type Ia supernovae, such as SN 2001el and SN 2012fr. However, the two models considered here cannot account for the unusually high level of polarization observed in extreme cases such as SN 2004dt.

US Highway 65 / IA-330 Improvements Polk and Jasper Counties, Iowa : Limited Phase I, Environmental Site Assessment, 1998

The Iowa Department of Transportation (IDOT) is currently considering improvements for US Highway 65 (US-65) and Iowa State Highway 330 (IA-330) in Polk and Jasper Counties, Iowa. As part of its project planning effort, IDOT is preparing an Environmental Assessment (EA) report which will include a section entitled "Hazardous Waste" to identify known sites in or near the proposed corridors that are, or could be, contaminated with hazardous or petroleum substances.

Aplicación de las políticas de crédito de FONAVIPO por medio las instituciones autorizadas (IA's) para facilitar el otorgamiento de créditos de vivienda al sector informal del área metropolítana de San Salvador.

La investigación se origina por la necesidad de FONAVIPO en obtener información sobre los requisitos que están imponiendo las Instituciones Autorizadas (IA´s) a las personas del Sector Informal del área metropolitana de San Salvador al momento que solicitan créditos para Vivienda, teniendo como propósito principal Identificar las políticas de crédito que influyen en el otorgamiento de créditos de vivienda al momento que este se solicita, con el fin de que mediante su aplicación se flexibilicen los requisitos para solicitar créditos para vivienda y así cumplir con los objetivos de FONAVIPO. De esta forma la institución contribuirá a reducir el número de familias sin acceso al crédito para una vivienda digna. La investigación ha sido abordada bajo la metodología del esquema científico, a través del Método Deductivo y con un diseño No Experimental. A nivel general dentro de los resultados más relevantes obtenidos de la investigación se tiene que: los créditos más solicitados por las personas del Sector Informal son compra de vivienda y compra de lote, pero además la mayoría de las personas manifiestan que el crédito no les fue otorgado, por no tener capacidad de pago, record crediticio y por falta de documentación que respalde sus ingresos además se pudo identificar que el Fondo Nacional de Vivienda Popular (FONAVIPO) sólo da a conocer las Instituciones Autorizadas (IA’s) y los tipos de crédito que otorgan, al momento que las personas visitan dicha institución para solicitar información sobre créditos de vivienda, como también se observó que las personas que laboran en las Instituciones Autorizadas (IA’s) no proporcionan la información necesaria sobre las líneas de crédito que promueve FONAVIPO Ante esta situación se diseña una Propuesta Sobre la Aplicación de las Políticas de Crédito de FONAVIPO que incluye una propuesta de requisitos de crédito, Medidas de Control para las Instituciones Autorizadas, así como también Medidas de Apoyo para FONAVIPO para que se dé a conocer en los diferentes medios de comunicación la siguiente información: Ubicación actual de FONAVIPO, los beneficios que brinda la Institución, los proyectos disponibles, los destinos de los créditos y sus Instituciones Autorizadas (IA’s).

Tjerita dari Boekoe Sam Kok In - Ia itoe di tjeritaken Soema Tong Siang jang Preksa Perkara Gantiken Giam Lo Ong

Cover contains Terkoempoel dari boekoe Roepa-Roepa Tjerita.

High-level concept annotation using ontology and probabilistic inference

Image annotation is a significant step towards semantic based image retrieval. Ontology is a popular approach for semantic representation and has been intensively studied for multimedia analysis. However, relations among concepts are seldom used to extract higher-level semantics. Moreover, the ontology inference is often crisp. This paper aims to enable sophisticated semantic querying of images, and thus contributes to 1) an ontology framework to contain both visual and contextual knowledge, and 2) a probabilistic inference approach to reason the high-level concepts based on different sources of information. The experiment on a natural scene database from LabelMe database shows encouraging results.