A Low-Cost Visible Light Positioning System for Indoor Positioning.

Currently, a high percentage of the world's population lives in urban areas, and this proportion will increase in the coming decades. In this context, indoor positioning systems (IPSs) have been a topic of great interest for researchers. On the other hand, Visible Light Communication (VLC) systems have advantages over RF technologies; for instance, they do not need satellite signals or the absence of electromagnetic interference to achieve positioning. Nowadays, in the context of Indoor Positioning (IPS), Visible Light Positioning (VLP) systems have become a strong alternative to RF-based systems, allowing the reduction in costs and time to market. This paper shows a low cost VLP solution for indoor systems. This includes multiple programmable beacons and a receiver which can be plugged to a smartphone running a specific app. The position information will be quickly and securely available through the interchange between the receiver and any configurable LED-beacon which is strategically disposed in an area. The implementation is simple, inexpensive, and no direct communication with any data server is required.

Interlaboratory proficiency processing scheme in CSF aliquoting: implementation and assessment based on biomarkers of Alzheimer's disease.

BACKGROUND: In this study, we tested to which extent possible between-center differences in standardized operating procedures (SOPs) for biobanking of cerebrospinal fluid (CSF) samples influence the homogeneity of the resulting aliquots and, consequently, the concentrations of the centrally analyzed selected Alzheimer's disease biomarkers. METHODS: Proficiency processing samples (PPSs), prepared by pooling of four individual CSF samples, were sent to 10 participating centers, which were asked to perform aliquoting of the PPSs into two secondary aliquots (SAs) under their local SOPs. The resulting SAs were shipped to the central laboratory, where the concentrations of amyloid beta (Aß) 1-42, pTau181, and albumin were measured in one run with validated routine analytical methods. Total variability of the concentrations, and its within-center and between-center components, were analyzed with hierarchical regression models. RESULTS: We observed neglectable variability in the concentrations of pTau181 and albumin across the centers and the aliquots. In contrast, the variability of the Aß1-42 concentrations was much larger (overall coefficient of variation 31%), with 28% of the between-laboratory component and 10% of the within-laboratory (i.e., between-aliquot) component. We identified duration of the preparation of the aliquots and the centrifugation force as two potential confounders influencing within-center variability and biomarker concentrations, respectively. CONCLUSIONS: Proficiency processing schemes provide objective evidence for the most critical preanalytical variables. Standardization of these variables may significantly enhance the quality of the collected biospecimens. Studies utilizing retrospective samples collected under different local SOPs need to consider such differences in the statistical evaluations of the data.

Producción de sevicios y prácticas populares de salud: una experiencia de integración de la Maestría en Práctica Social y Salud / Production of health services and popular health practices: an integration experience from the Master in Social Practice and Health

La producción de sevicios y prácticas populares de salud, identifica un área que se desarrolla en la Maestría en Práctica Social y Salud desde 1993 en la FOUCV. Nos permite desde el espacio concreto de los servicios y con la comunidad, el abordaje de la situación de la salud colectiva. Pretendemos desde el quehacer en los servicios, analizar la práctica y descubrir sus relaciones con la totalidad, rescatar su objetivo social y retroalimentar el proceso donde los actores involucrados y la práctica misma se transforman, a partir de las decisiones del colectivo y de su acción comprometida en el espacio social de la Salud. Ello, solo es posible a través del esfuerzo conjunto desde diferentes áreas que componen el curso de maestría por la integración. Desde y hacia su interior, con los cursantes y donde el quehacer de los mismos con la comunidad y de la propia comunidad. Presentamos en este papel parte de nuestra experiencia, una visión desde el área

Venezuela, desde la antesala de los noventa / Venezuela, from the hall of the ninety

Venezuela en medio de una crisis socio-económica y política, intenta, a partir de 1989, cambiar de un estado de bienestar social a un estado neoliberal; bajo las recomendaciones del Fondo Monetario Internacional, el Banco Mundial y del Banco Interamericano de Desarrollo (FMI, BM, BID). El desarrollo del proceso ha sido traumático y afecta drásticamente a los sectores menos favorecidos de la población. El estado parece debilitarse progresivamente y se pierden los referentes nacionales. Todo ello fue estudiado exhaustivamente en la década de los ochenta y antes de la aplicación de las primeras medidas económicas; muchos autores presentaron sus análisis, anunciaron sus expectativas y argumentaron posibles salidas ante la crisis. Sin embargo, nuestros gobiernos insisten en actuar erradamente a espaldas del colectivo interés nacional, escribiendo las páginas más dolorosas de nuestra historia contemporánea por la ausencia de una voluntad política nacional, de un verdadero compromiso con la sociedad venezolana