Search

In order to determine the frequency and severity of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (MD), a cross-sectional descriptive study was conducted in 3,239 patients of the Regional Institute of Ophthalmology in the city of Trujillo, La Libertad region, Peru. After pupil dilation, trained personnel took two photographs of each eye, centered on macula and optic nerve. The frequency of DR was 25.9%, with a higher proportion in men with DR (28.2%) and in those with more than 10 years of MD disease (49.0%). Most patients had mild to moderate non-proliferative diabetic retinopathy (NPDR) (79.3%); 10.1% had severe NPDR, and 9.7% had proliferative DR. We conclude that DR occurs in one in four patients and about 20% in advanced degrees. There is a need to expand screening coverage from the time of diagnosis of DM and to implement preventive measures such as metabolic control and periodic ocular fundus exam. [ABSTRACT FROM AUTHOR]

We analyze the limitations of two-dimensional (2D) raster digital images for graphic representation of documents with volume or three-dimensional (3D) elements, proposing a visual model based on 3D techniques that complements the visual information conveyed by the 2D raster images that are usually offered in digital archives or library services. The proposed model concurrently applies stereoscopic photography techniques, reflectance transformation imaging (RTI) and 3D models obtained by structure for motion (SfM) procedures. [ABSTRACT FROM AUTHOR]

Copyright of Enl@ce: Revista Venezolana de Información, Tecnología y Conocimiento is the property of Universidad del Zulia, Laboratorio de Investigacion y Sistemas de Informacion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents a survey of international research studies and development in digital preservation, devoting a section to the situation in Spain. The author outlines applications in areas such as institutional repositories, administrative records, personal archives, aerospace industry and museum archives, but the greatest attention is given to digital preservation applications in libraries and archives. The pre-eminent role of certain libraries and the national archives and records of certain countries is evident in an analysis of the protagonists of this research, as well as the emerging role of software companies. The major lines of research include the integration of tools to create integrated preservation systems. [ABSTRACT FROM AUTHOR]

The evaluation and description of image quality after applying lossy compression is described. It remains an open research issue in the sense of finding an objective criterion to stop lossy compression at a maximum level of compression with a minimum distortion. This value is found by implementing a set of quantitative bivariate measures such as the Mean Square Error (MSE), the Peak Signal to Noise Ratio (PSNR), the Structural Simmilarity index (SSIM index) and the Spectral Distance among others. A review is also done about the physical meaning of prediction algorithms for quality comparison such as the Hotelling Observer (HO), the channelized forms (CHO and LGHO), and the Non-Prewhitened Matched Filter (NPWE). Finally, the subjective evaluation of image quality is investigated through ROC analysis based on diagnostic performance curves. [ABSTRACT FROM AUTHOR]