Daylight Spectrum Index: A New Metric to Assess the Affinity of Light Sources with Daylighting

The current scenario of colorimetry shows a wide variety of different metrics which do not converge in the assessment of the color rendering of light sources. The limitations of the Color Rendering Index have promoted the emergence of new metrics, such as the Color Quality Scale. As in the case of the previous metric, these new concepts are based on the analysis of the deviation of different color samples in a color space, contrasting the results with those obtained with a light source reference, which can vary depending on the color temperature. Within this context, the Daylight Spectrum Index is proposed. This new concept aims to determine the affinity with daylighting of electric light sources, comparing the resulting spectral power distributions of the lamps studied and that observed under natural light. The affinity of an electric light source with daylighting allows for lower energy consumption due to the better performance of human vision. The new metric proposed is evaluated following the results obtained from 80 surveys, demonstrating the usefulness of this new concept in the quantification of color rendering of LED lamps and the affinity of electric light sources with daylighting.Government of Spain BIA2017-86997-

Analytical modeling of reinforced concrete columns subjected to bidirectional shear

Under general seismic loading, reinforced concrete columns may be subjected to lateral loads in more than one direction. Available experimental data on columns subjected to bidirectional forces indicate that higher levels of damage and a higher loss of ductility and strength have been observed compared to similar tests under unidirectional shear forces. In this study, an experimental program was conducted in which six lightly reinforced concrete columns were subjected to unidirectional and bidirectional cyclic shear forces. This observation was used to identify the mechanisms and parameters governing the behavior of columns subjected to cyclic bidirectional lateral loads. Hence, a new conceptual model was developed to obtain the capacity of member. The shear forces were analyzed and an analytical formulation was derived to account for the effects in the concrete stress-strain relationship, the moment-curvature diagram and the plastic hinge length. These equations were used along with a structural model with concentrated plastic hinges to obtain the capacity curve of the column. The results of the formulations developed were verified using the results of the experiments performed on columns subjected to unidirectional and bidirectional cyclic lateral forces.Peer ReviewedPostprint (author's final draft

Correlations and preliminary validation of laboratory asphalt binder and HMA reflective cracking resistance to field performance of in-service highway sections

Reflective cracking is one of the dominant distress modes occurring when hot-mix asphalt (HMA) overlays are placed over existing cracked flexible and/or jointed rigid pavements. Various tests have been conducted in the literature for measuring, characterizing, and quantifying the cracking resistance potential of HMA mixes in the laboratory. Asphalt-binder is one of the key constituent elements that significantly influences and controls the fracture behavior and cracking performance of hot-mix asphalt (HMA), both in the laboratory and field. In particular, the low-temperature rheological properties of the asphalt-binders are very critical in terms of improving the HMA fracture properties in the laboratory and ultimately mitigating cracking in the field. The Elastic Recovery (ER) and Bending Beam Rheometer (BBR) are the most widely used laboratory test methods for evaluating and quantifying the asphalt-binder behavior at low temperatures, mostly using the ductility (ER), stiffness (S), and m-value parameters. Some cracking test related to mixes have been studied, both of dynamic and monotonic loading modes. However, one key challenge with most of these laboratory tests is correlations and validation with field performance data. Quite often, field data availability is a challenge or otherwise, needs costly long-term performance monitoring. Using the Texas flexible pavements and overlays database, namely the Texas Data Storage System (DSS), as the data source, this study was conducted to correlate and preliminarily validate the asphalt-binder low-temperature properties (measured using the BBR and ER tests) and laboratory monotonic-loading overlay tester (OT) to the field crack (reflective) performance of in-service highway sections.MaestríaMagister en Ingeniería Civi

Carta de Pedro de San Buenaventura a fray Bernardino de Sahagún acerca del calendario solar mexicano.

Sin resume

Del petróleo a la bio-inteligencia. Cambio de matriz productiva y economía del conocimiento. Discurso, realidad y proyecciones del caso ecuatoriano

Este artículo pretende analizar críticamente y exponer el proceso de apropiación y explotación de los recursos en Ecuador, el cual se vincula con el objetivo político de la soberanía sobre aquellos recursos y los procesos propuestos de cambio de la matriz productiva, junto a la búsqueda de construcción de una economía social del conocimiento, enfatizando en la relevancia de la planificación, la inversión en ciencia y tecnología, y la institucionalización de estas acciones en normas, leyes, organismos y políticas públicas. La propuesta se realiza a través de la revisión, estudio y análisis de documentación oficial, complementada con material de prensa y contrastada con información emanada de fuentes institucionales. Finalmente, se establecen algunas propuestas y conclusiones como elementos que pudiesen contribuir en los procesos señalados particularmente en Ecuador, y, más ampliamente, en otras experiencias de apropiación y utilización soberana de los recursos naturales y búsqueda del desarrollo en América Latina

Impact on outcomes across KDIGO-2012 AKI criteria according to baseline renal function

Producción CientíficaAcute kidney injury (AKI) and Chronic Kidney Disease (CKD) are global health problems. The pathophysiology of acute-on-chronic kidney disease (AoCKD) is not well understood. We aimed to study clinical outcomes in patients with previous normal (pure acute kidney injury; P-AKI) or impaired kidney function (AoCKD) across the 2012 Kidney Disease Improving Global Outcomes (KDIGO) AKI classification. We performed a retrospective study of patients with AKI, divided into P-AKI and AoCKD groups, evaluating clinical and epidemiological features, distribution across KDIGO-2012 criteria, in-hospital mortality and need for dialysis. One thousand, two hundred and sixty-nine subjects were included. AoCKD individuals were older and had higher comorbidity. P-AKI individuals fulfilled more often the serum creatinine (SCr) > 3.0x criterion in AKI-Stage3, AoCKD subjects reached SCr > 4.0 mg/dL criterion more frequently. AKI severity was associated with in-hospital mortality independently of baseline renal function. AoCKD subjects presented higher mortality when fulfilling AKI-Stage1 criteria or SCr > 3.0x criterion within AKI-Stage3. The relationship between mortality and associated risk factors, such as the net increase of SCr or AoCKD status, fluctuated depending on AKI stage and stage criteria sub-strata. AoCKD patients that fulfil SCr increment rate criteria may be exposed to more severe insults, possibly explaining the higher mortality. AoCKD may constitute a unique clinical syndrome. Adequate staging criteria may help prompt diagnosis and administration of appropriate therapy

La conformación de la Antropología como disciplina científica, el Museo Nacional de México y los Congresos Internacionales de Américanistas

This work analyses the process through which the Mexican National Museum —originally embracing all branches of knowledge— reached both institutional maturity and highest social significance in the form of an Anthropological Museum. This case study shows how necessary it is to critically reformulate the current presuppositions and theories dealing with the origin and institutionalization of Anthropology as a discipline.En este trabajo se analiza el proceso por el que el Museo Nacional de México, originalmente un museo que abarcaba todas las ramas del saber, alcanza su madurez institucional y su máxima significación social como un Museo de Antropología. Un caso de estudio que muestra la necesidad de replantear críticamente los presupuestos y teorías habitualmente más aceptados acerca del origen e institucionalización de la Antropología como disciplina