13,101 research outputs found
Solar science with the Atacama Large Millimeter/submillimeter Array - A new view of our Sun
The Atacama Large Millimeter/submillimeter Array (ALMA) is a new powerful
tool for observing the Sun at high spatial, temporal, and spectral resolution.
These capabilities can address a broad range of fundamental scientific
questions in solar physics. The radiation observed by ALMA originates mostly
from the chromosphere - a complex and dynamic region between the photosphere
and corona, which plays a crucial role in the transport of energy and matter
and, ultimately, the heating of the outer layers of the solar atmosphere. Based
on first solar test observations, strategies for regular solar campaigns are
currently being developed. State-of-the-art numerical simulations of the solar
atmosphere and modeling of instrumental effects can help constrain and optimize
future observing modes for ALMA. Here we present a short technical description
of ALMA and an overview of past efforts and future possibilities for solar
observations at submillimeter and millimeter wavelengths. In addition, selected
numerical simulations and observations at other wavelengths demonstrate ALMA's
scientific potential for studying the Sun for a large range of science cases.Comment: 73 pages, 21 figures ; Space Science Reviews (accepted December 10th,
2015); accepted versio
Photo-damage, photo-protection and age-related macular degeneration
Age-related macular degeneration (AMD) is a degenerative retinal disease that causes blindness in people 60-65 years and older, with the highest prevalence appearing in people 90 years-old or more. Epidemiological estimates indicate that the number of cases is increasing, and will almost double in the next 20 years. Preventive measures require precise etiological knowledge. This is quite difficult, since AMD is a multifactorial condition with intricate relationships between causes and risk factors. In this review, we describe the impact of light on the structure and physiology of the retina and the pigment epithelium, taking into account the continuous exposure to natural and artificial light sources along the life of an individual. A large body of experimental evidence demonstrates the toxic effects of some lighting conditions on the retina and the pigment epithelium, and consensus exists about the importance of photo-oxidation phenomena in the causality chain between light and retinal damage. Here, we analyzed the transmission of light to the retina, and compared the aging human macula in healthy and diseased retinas, as shown by histology and non-invasive imaging systems. Finally, we have compared the putative retinal photo-sensitive molecular structures that might be involved in the genesis of AMD. The relationship between these compounds and retinal damage supports the hypothesis of light as an important initiating cause of AMD.Fil: Marquioni Ramella, Melisa Daniela. Universidad Austral. Facultad de Ciencias BiomĂ©dicas. Laboratorio de Investigaciones BiomĂ©dicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Suburo, Angela Maria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Austral. Facultad de Ciencias BiomĂ©dicas. Laboratorio de Investigaciones BiomĂ©dicas; Argentin
- …