Sensitivity of Modern Lighting Technologies to Rapid Voltage Changes

Rapid Voltage Changes (RVCs) are one of the Power Quality disturbances that are recently receiving a lot of attention from the point of view of international standards. However, although they can cause or contribute to flicker, IEC 61000-4-15 only addresses periodic amplitude fluctuations and more effort is needed to regulate the occurrence of RVCs, according to their effect on flicker perceptibility. Alongside, flicker perception is challenged by the integration of modern lighting technology, whose response is different from the traditional incandescent lamp. This paper studies the connection between the increasing importance of RVCs and the evolution of illumination technologies. Sensitivity of modern lighting technologies to RVCs is studied by measuring flicker with a high precision light flickermeter. A large set of modern lamps is tested and the relationship between RVCs parameters and flicker perceptibility is analyzed

Metodología de selección de especies de arbolado para el sombreado urbano en la parte oriental de la cornisa Cantábrica

The mitigation of the Urban Heat Island is one of the biggest future challenges in cities due to climate change. One of the methods to achieve the cooling of urban spaces is the attenuation of solar radiation provided by the trees. In the present article, a methodology of selection of arboreal species is proposed for the improvement of thermal comfort in urbanized areas of the eastern part of the Cantabrian coast. Starting from a pre-selection of native species, a classification of various species suitable for shading is obtained, describing its main characteristics and its possible use scope according to the typology of urban space.La mitigación del efecto Isla de Calor es uno de los mayores retos del futuro en las ciudades debido al cambio climático. Uno de los métodos para conseguir el enfriamiento de los espacios urbanos es la atenuación de radiación solar proporcionada por el arbolado. En el presente artículo se plantea una metodología de selección de especies arbóreas para la mejora del confort térmico en zonas urbanizadas de la parte oriental de la cornisa cantábrica. Partiendo de una preselección de especies autóctonas, se obtiene una clasificación de diversas especies aptas para el sombreado describiéndose sus principales características y su posible ámbito de utilización en función de la tipología de espacio urbano

Efecto de la localización del electrodo ventricular izquierdo sobre los parámetros ecocardiográficos de asincronía en pacientes sometidos a terapia de resincronización cardíaca

Introduction and objectives. Cardiac resynchronization therapy has been shown to be an option in the treatment of patients with congestive heart failure. The current indication for this treatment is based on clinical and electrocardiographic criteria, although echocardiography has also been shown to be a useful tool for the diagnosis of ventricular dyssynchrony. The aim of this study was to assess left ventricular dyssynchrony by echocardiography and to evaluate the effect of the stimulation site on the magnitude of resynchronization. Patients and method. We studied 25 patients with biventricular stimulation (left ventricular lead located in a lateral position in 13 patients, and in an anterior position in 12). A complete echo-Doppler evaluation, including left ventricular ejection fraction, ventricular diameters and parameters of inter- and intraventricular dyssynchrony, was performed before implantation and 3 months after the procedure, with the device connected and disconnected. Results. Left ventricular ejection fraction increased significantly from 23.7 (6.5) to 27.8 (5.5) (P=.007) at 3 months. In the group as a whole, biventricular pacing was associated with a significant decrease in all intraventricular dyssynchrony parameters (septal-to-lateral wall motion delay and septal-to-posterior wall motion delay). This decrease in septal-to-posterior wall motion delay and septalto- lateral wall motion delay was significantly greater in patients with the electrode implanted in the lateral position (58.1 ms vs 118 ms; P=.02) than with the lead in the anterior position (39.5 ms vs 86.5 ms; P=.04). Three patients, all with the electrode in an anterior location, were considered non-responders. Conclusions. Left lateral free wall stimulation provided significantly better intraventricular resynchronization compared to stimulation at an anterior site. Echocardiography is a useful tool to evaluate changes in intra- and interventricular synchrony related to the pacing site

Tratamiento de la insuficiencia cardíaca avanzada mediante estimulación biventricular. Experiencia inicial en una serie de 22 casos consecutivos

Recent data suggest that biventricular pacing may play an important role in treating advanced heart failure in the presence of a significant interventricular and/or intraventricular conduction disorder by correcting cardiac dysynchrony. In this article, we review the initial technical and clinical experience with cardiac resynchronization therapy in an electrophysiology laboratory. METHODS: The first 22 consecutive patients with severe congestive heart failure, ejection fraction < 0.35, NYHA functional class III or IV, and QRS duration > 120 ms who were implanted biventricular pacemakers were studied. Clinical, electrocardiographic, and echocardiographic evaluations were made before and three months after pacemaker implantation. Acute functional capacity testing with peak oxygen uptake was measured during biventricular pacing and during intrinsic rhythm or right ventricular pacing three months after the implantation procedure. RESULTS: The success rate of pacemaker implantation was 95%. Pre-discharge left ventricular pacing was achieved in 91%, with an average pacing threshold of 1.53 (1.04) volts. NYHA functional class improved (p = 0.039) from 3.4 (0.7) to 2.3 (0.78). The rate of hospitalization for heart failure decreased from an average of 3.12 (0.58) three months before the procedure to 1.38 (0.34) three months after the procedure. Peak oxygen uptake was significantly greater (p = 0.028) during biventricular pacing: 14.89 (2.1) ml/min/kg, than during intrinsic rhythm or right ventricular pacing: 12.65 (2.3) ml/min/kg. CONCLUSIONS: Cardiac resynchronization therapy can be performed safely and with a high success rate in the electrophysiology laboratory. Biventricular pacing seems to improve the symptoms of congestive heart failure in patients with evidence of atrioventricular and/or interventricular/intraventricular dysynchrony. An acute benefit in peak oxygen uptake was associated with biventricular pacing after the implantation procedure

Preliminary Evidence for an Association Between the Composition of the Gut Microbiome and Cognitive Function in Neurologically Healthy Older Adults

Objectives: Dysbiosis of the gut microbiome is implicated in numerous human health conditions. Animal studies have linked microbiome disruption to changes in cognitive functioning, although no study has examined this possibility in neurologically healthy older adults. Methods: Participants were 43 community-dwelling older adults (50-85 years) that completed a brief cognitive test battery and provided stool samples for gut microbiome sequencing. Participants performing ≥ 1 SD below normative performance on two or more tests were compared to persons with one or fewer impaired scores. Results: Mann Whitney U tests revealed different distributions of Bacteroidetes (p = .01), Firmicutes (p = .02), Proteobacteria (p = .04), and Verrucomicrobia (p = .003) between Intact and Impaired groups. These phyla were significantly correlated with cognitive test performances, particularly Verrucomicrobia and attention/executive function measures. Conclusions: The current findings suggest that composition of the gut microbiome is associated with cognitive test performance in neurologically healthy older adults. Future studies are needed to confirm these findings and explore possible mechanisms. (JINS, 2017, 23, 700-705