2,960 research outputs found
Zero phase sequence voltage injection for the alternate arm converter
The Alternate Arm Converter (AAC) is a voltage source converter being developed as an alternative to the Modular Multilevel Converter (MMC) for HVDC power transmission and reactive power compensation. Each Arm of the converter contains high voltage series IGBT Director Switches and full-bridge cells, which enables the VSC to ride through AC and DC network faults. This paper describes how the AAC can be optimised by modulating the converter terminal voltages with zerophase sequence triplen harmonic components. The optimisation reduces the ratio of the number of the full-bridge cells compared to the simpler Director Switches which offers a valuable improvement in footprint and efficiency
Evidence on the Bidirectional Relationship Between Health and Life Satisfaction in Older Adults
AbstractPrevious research on health and life satisfaction in older adults has suggested a bidirectional relationship. However, most evidence either is based on cross-sectional data, being unsuitable for inferring any directionality on the results, or disregards the within-person stability of both variables over time, thus providing potentially biased results. We analysed data from 11,667 older adults interviewed between 2008 and 2016 within the English Longitudinal Study of Ageing. A health measure including self-reported and measured tests on cognitive and physical performance was computed using a Bayesian multilevel item-response theory approach. Life satisfaction was assessed with the Satisfaction with Life Scale. Cross-lagged models using a Structural Equation Modelling approach were used to analyse the longitudinal interrelation between health and life satisfaction. Models accounting and not accounting for the within-person stability in the measures were computed. Additional sensitivity models were ran using an exclusively self-reported measure of health. Health and life satisfaction were significant longitudinal predictors of one another only when the within-person stability was not considered. The effect of life satisfaction on health became negligible once that stability was modelled. The impact of not accounting for within-person stability was larger when health was measured exclusively with self-reported information. Our study suggests that health and life satisfaction are not bidirectionally related in older adults, but only health predicts a better life satisfaction over time. Thus, policies aimed at fostering older adults’ life satisfaction by focusing on health enhancement and maintenance may be fruitful, whereas the opposite may not.</jats:p
An Ecological Alternative to Snodgrass & Vanderwart: 360 High Quality Colour Images with Norms for Seven Psycholinguistic Variables
This work presents a new set of 360 high quality colour images belonging to 23 semantic subcategories. Two hundred and thirty-six Spanish speakers named the items and also provided data from seven relevant psycholinguistic variables: age of acquisition, familiarity, manipulability, name agreement, typicality and visual complexity. Furthermore, we also present lexical frequency data derived from Internet search hits. Apart from the high number of variables evaluated, knowing that it affects the processing of stimuli, this new set presents important advantages over other similar image corpi: (a) this corpus presents a broad number of subcategories and images; for example, this will permit researchers to select stimuli of appropriate difficulty as required, (e.g., to deal with problems derived from ceiling effects); (b) the fact of using coloured stimuli provides a more realistic, ecologically-valid, representation of real life objects. In sum, this set of stimuli provides a useful tool for research on visual object-and word- processing, both in neurological patients and in healthy controls
Perinatal Tuberculosis: Is it a Forgotten Disease?
Perinatal tuberculosis is an uncommon condition but with a high mortality and a challenging diagnosis. We present four cases of perinatal tuberculosis managed between 1991-2014 in a Spanish Tertiary Hospital. The infection should be considered in patients with progressive respiratory symptoms and with a poor response to conventional antibiotic therapy, especially in those with positive epidemiologic risk. Bronchoscopy can be a useful tool for diagnosis
Pathogen burden, inflammation, proliferation and apoptosis in human in-stent restenosis - Tissue characteristics compared to primary atherosclerosis
Pathogenic events leading to in-stent restenosis (ISR) are still incompletely understood. Among others, inflammation, immune reactions, deregulated cell death and growth have been suggested. Therefore, atherectomy probes from 21 patients with symptomatic ISR were analyzed by immunohistochemistry for pathogen burden and compared to primary target lesions from 20 stable angina patients. While cytomegalovirus, herpes simplex virus, Epstein-Barr virus and Helicobacter pylori were not found in ISR, acute and/or persistent chlamydial infection were present in 6/21 of these lesions (29%). Expression of human heat shock protein 60 was found in 8/21 of probes (38%). Indicated by distinct signals of CD68, CD40 and CRP, inflammation was present in 5/21 (24%), 3/21 (14%) and 2/21 (10%) of ISR cases. Cell density of ISR was significantly higher than that of primary lesions ( 977 +/- 315 vs. 431 +/- 148 cells/mm(2); p < 0.001). There was no replicating cell as shown by Ki67 or PCNA. TUNEL+ cells indicating apoptosis were seen in 6/21 of ISR specimens (29%). Quantitative analysis revealed lower expression levels for each intimal determinant in ISR compared to primary atheroma (all p < 0.05). In summary, human ISR at the time of clinical presentation is characterized by low frequency of pathogen burden and inflammation, but pronounced hypercellularity, low apoptosis and absence of proliferation. Copyright (C) 2004 S. Karger AG, Basel
Coupling of individual quantum emitters to channel plasmons.
Efficient light-matter interaction lies at the heart of many emerging technologies that seek on-chip integration of solid-state photonic systems. Plasmonic waveguides, which guide the radiation in the form of strongly confined surface plasmon-polariton modes, represent a promising solution to manipulate single photons in coplanar architectures with unprecedented small footprints. Here we demonstrate coupling of the emission from a single quantum emitter to the channel plasmon polaritons supported by a V-groove plasmonic waveguide. Extensive theoretical simulations enable us to determine the position and orientation of the quantum emitter for optimum coupling. Concomitantly with these predictions, we demonstrate experimentally that 42% of a single nitrogen-vacancy centre emission efficiently couples into the supported modes of the V-groove. This work paves the way towards practical realization of efficient and long distance transfer of energy for integrated solid-state quantum systems.E.B.-U., R.M., M.G. and R.Q. acknowledge the European Community’s Seventh Framework Programme (grant ERC- Plasmolight; no. 259196) and Fundació privada CELLEX. E.B.-U. acknowledges support of the FPI fellowship from the Spanish MICINN. R.M. acknowledges support of Marie Curie and NEST fellowships. C.G.-B. and F.J.G.-V. acknowledge the European Research Council (ERC-2011-AdG, Proposal No. 290981). C.G.-B., E.M., and F.J.G.-V. acknowledge the Spanish MINECO (Contract No. MAT2011-28581-C02-01). C.G.-B. acknowledges support of the FPU fellowship from the Spanish MECD. I.P.R., T.H. and S.I.B. acknowledge financial support for this work from the Danish Council for Independent Research (the FTP project ANAP, Contract No. 09-072949) and from the European Research Council, Grant No. 341054 (PLAQNAP). Y.A. acknowledges the support of RYC-2011-08471 fellowship from MICINN. We thank Luis Martin-Moreno and Cesar E. García for fruitful discussions, Jana M. Say and Louise J. Brown for providing the ND solution, and Ioannis Tsioutsios for support with the AFM manipulation technique.This is the final published version. It first appeared at http://www.nature.com/ncomms/2015/150807/ncomms8883/full/ncomms8883.html
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