680 research outputs found
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Incentive Regulation, Productivity Growth and Environmental Effects: The Case of Electricity Networks in Great Britain
We analyse the productivity growth of electricity transmission and distribution networks in Great Britain and how changes in incentive mechanism have influenced the measured total factor productivity (TFP). In doing so we are also concerned to examine the effects of quality of service and environmental targets on measured productivity growth. It is increasingly important that productivity measures adjust for the increasing regulatory pressure to reduce the wider societal impacts of the electricity sector and improve quality of service. Failure to do so, may mean that productivity growth may look slower than it actually is. We employ a DEA technique which considers the underlying data without a stochastic element. Our findings show that productivity growth is consistently low for the period we examine, in the region of 1% p.a. over the 29 years from 1990/1991-2018/2019. For both electricity transmission and electricity distribution we try to monetise a wider range of quality and emissions variables in order to show the difference their inclusion makes to measured productivity growth. We show that it can make a difference both positively and negatively, though often this difference is small (e.g. 0.1% p.a.). However, the impact can be much larger (c. 1% p.a.), especially with respect to improvements in quality of service in the distribution network. In the context of generally slow productivity growth, we therefore show the importance of appropriate measurement
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The Productivity Puzzle in Network Industries: Evidence from the Energy Sector
What accounts for the recent widespread slowdown in the productivity in advanced economies has remained a puzzle. One plausible explanation has been attributable to regulation, particularly anti-competitive regulations and environmental regulations. Thi
Stabilized mixed approximation of axisymmetric Brinkman flows
This paper is devoted to the numerical analysis of an augmented finite element approximation of the axisymmetric Brinkman equations. Stabilization of the variational formulation is achieved by adding suitable Galerkin least-squares terms, allowing us to transform the original problem into a formulation better suited for performing its stability analysis. The sought quantities (here velocity, vorticity, and pressure) are approximated by Raviart−Thomas elements of arbitrary order k ≥ 0, piecewise continuous polynomials of degree k + 1, and piecewise polynomials of degree k, respectively. The well-posedness of the resulting continuous and discrete variational problems is rigorously derived by virtue of the classical Babuška–Brezzi theory. We further establish a priori error estimates in the natural norms, and we provide a few numerical tests illustrating the behavior of the proposed augmented scheme and confirming our theoretical findings regarding optimal convergence of the approximate solutions
Localization and Capacitance Fluctuations in Disordered Au Nano-junctions
Nano-junctions, containing atomic-scale gold contacts between strongly
disordered leads, exhibit different transport properties at room temperature
and at low temperature. At room temperature, the nano-junctions exhibit
conductance quantization effects. At low temperatures, the contacts exhibit
Coulomb-Blockade. We show that the differences between the room-temperature and
low temperature properties arise from the localization of electronic states in
the leads. The charging energy and capacitance of the nano-junctions exhibit
strong fluctuations with applied magnetic field at low temperature, as
predicted theoretically.Comment: 20 pages 8 figure
Immediate effect of cryotherapy on the spastic reflex excitability in people with spasticity post-stroke
Introducción: Existe controversia sobre los efectos terapéuticos de la crioterapia en el músculo espástico y las implicaciones clínicas que fundamentan su uso como coadyuvante en el proceso de rehabilitación. Objetivo: Evaluar el efecto inmediato de la aplicación del paquete de hielo sobre la excitabilidad refleja en la musculatura plantiflexora espástica en personas post-ECV. Métodos: Estudio experimental de mediciones repetidas con asignación aleatoria a dos grupos de intervención: Grupo Experimental (n=10) y Grupo Control (n=5). Se registró latencia (ms), duración (ms) y amplitud (mV) de las ondas M y H y el índice de amplitud Hmáximo/Mmáximo (%) antes y después de la crioterapia o reposo. Los participantes fueron quince individuos de ambos géneros con hemiparesia espástica post-ECV, edad media de 60,7±10,7años, mediana tiempo de evolución 36 meses (RIC17-49). No hubo diferencias significativas en las características basales entre los grupos de intervención. Resultados: La crioterapia induce un aumento estadísticamente significativo en la latencia de la onda H (32,9±3,3 vs. 34,9±3,6ms, p<0,001) y M (8,0±1,9 vs. 9,4±2,4ms, p<0,05) y en la duración de la onda M (6,3±1,3 vs. 9,8±2,2ms, p<0,001) y H (7,2±1,6 vs. 9,9± 2,0ms, p<0,001). No se determinaron cambios significativos en la amplitud, ni en el índice Hmáx/Mmáx. Conclusiones: Nuestros hallazgos sugieren que el enfriamiento puede ser útil para el tratamiento de la espasticidad, pues retrasa la respuesta muscular evocada por estimulación eléctrica directa y refleja. A su vez, prolonga el período refractario del potencial de acción, por lo cual se requeriría más tiempo para activar las fibras musculares.Introduction: There is controversy about the therapeutic effects of cryotherapy on spasticity and clinical implications underlying its use as an adjunct in the rehabilitation process. Objetive: To evaluate the immediate effect of the application of ice pack on the H-reflex excitability in spastic muscles post-stroke people. Methods: A randomized experimental study of repeated measurements, with two intervention groups, was performed: Experimental group (n=10) and control group (n=5). Latency (ms) duration (ms) and amplitude (mV) of M and H waves and the amplitude index Hmáximo / Mmáximo (%) were recorded before and after cryotherapy or rest. The participants were fifteen subjects with spastic hemiparesis post-stroke were screened, mean age 60.7±10.7 years, median of injury duration 36 months (IQR17-49). There were no significant differences in baseline characteristics between the intervention groups. Results: Cryotherapy induces a statistically significant increase in the H wave latency (32.9±3.3 vs. 34.9± 3.6ms, p<0,001) and M wave (8.0±1.9 vs. 2.4ms±9.4, p< 0.05); as well as, increase was observed in the duration of the M wave (6.3±1.3 vs. 9.8±2.2ms, p<0.001) and H (7.2±1.6 vs. 9.9±2.0ms, p<0.001). No significant changes in the amplitude or the Hmax/Mmax ratio were determined. There were no differences between the H-reflex or the M-wave variables recorded before and after in the control group. Conclusions: Our findings suggest that cooling may be useful for the treatment of spasticity, due to it delays muscle response evoked by direct and reflects electrical stimulation. Simultaneously, cooling prolongs the refractory period of the action potential, whereby more time is required to activate the muscle fibers
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Neutron metrology for SBSS
This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this work is to develop new detector technologies for Science-Based Stockpile Stewardship (SBSS) at the Los Alamos Neutron Scattering Center (LANSCE) using existing expertise and infrastructure from the nuclear and particle physics programs at LANL
Distance protection algorithm for multiterminal HVDC systems using the Hilbert–Huang transform
Multiterminal high-voltage direct current (HVDC) systems still need advances in terms of protection in order to improve their reliability. In this context, the distance protection can play a major role by adding selectivity to the existing DC fault detection algorithms. Hence, the present work proposes a non-unit DC distance protection algorithm that uses the frequency of the DC voltage transient oscillation to estimate the distance of the fault. The DC voltage transient frequency is extracted using the Hilbert–Huang transform and compared with a pre-defined frequency/distance curve. The technique was evaluated by simulating faults in a four-terminal symmetric monopole multiterminal HVDC system. In the simulation environment the algorithm was fully selective for faults within the first protection zone and had a correct operation rate of 94% or more for faults located in the second protection zone. To further validate the presented technique, the proposed algorithm was embedded in a digital signal controller, running in real-time. In all performed tests in hardware, the faults were correctly detected and identified as being internal or external. The results indicate that the proposed algorithm could be used in real-world applications, in conjunction with fault detection techniques, adding selectivity to multiterminal DC protection schemes
Atlas construction and spatial normalisation to facilitate radiation-induced late effects research in childhood cancer
Reducing radiation-induced side effects is one of the most important challenges in paediatric cancer treatment. Recently, there has been growing interest in using spatial normalisation to enable voxel-based analysis of radiation-induced toxicities in a variety of patient groups. The need to consider three-dimensional distribution of doses, rather than dose-volume histograms, is desirable but not yet explored in paediatric populations. In this paper, we investigate the feasibility of atlas construction and spatial normalisation in paediatric radiotherapy. We used planning computed tomography (CT) scans from twenty paediatric patients historically treated with craniospinal irradiation to generate a template CT that is suitable for spatial normalisation. This childhood cancer population representative template was constructed using groupwise image registration. An independent set of 53 subjects from a variety of childhood malignancies was then used to assess the quality of the propagation of new subjects to this common reference space using deformable image registration (i.e., spatial normalisation). The method was evaluated in terms of overall image similarity metrics, contour similarity and preservation of dose-volume properties. After spatial normalisation, we report a dice similarity coefficient of 0.95±0.05, 0.85±0.04, 0.96±0.01, 0.91±0.03, 0.83±0.06 and 0.65±0.16 for brain and spinal canal, ocular globes, lungs, liver, kidneys and bladder. We then demonstrated the potential advantages of an atlas-based approach to study the risk of second malignant neoplasms after radiotherapy. Our findings indicate satisfactory mapping between a heterogeneous group of patients and the template CT. The poorest performance was for organs in the abdominal and pelvic region, likely due to respiratory and physiological motion and to the highly deformable nature of abdominal organs. More specialised algorithms should be explored in the future to improve mapping in these regions. This study is the first step toward voxel-based analysis in radiation-induced toxicities following paediatric radiotherapy
Training Habits of Eumenorrheic Active Women during the Different Phases of Their Menstrual Cycle: A Descriptive Study
This research was supported by the Pre-competitive Projects for Early Stage
Researchers Program from the University of Granada (ref: PPJIA2020.03). The authors would like to
thank all the participants.This study meets the ethical standards of theWorld Medical
Association’s Declaration of Helsinki (2013), and it was approved by the Institutional Review Board
(Universidad de La Frontera, Temucho, Chile, 005_19).Informed consent was obtained from all subjects involved in the study.The purpose of this study was to examine the training habits of eumenorrheic active women during their menstrual cycle (MC), and its perceived influence on physical performance regarding their athletic level. A group of 1250 sportswomen filled in a questionnaire referring to demographic information, athletic performance and MC-related training habits. Of the participants, 81% reported having a stable duration of MC, with most of them (57%) lasting 26-30 days. Concerning MC-related training habits, 79% indicated that their MC affects athletic performance, although 71% did not consider their MC in their training program, with no differences or modifications in training volume or in training intensity for low-level athletes (LLA) and high-level athletes (HLA) with hormonal contraceptive (HC) use. However, LLA with a normal MC adapted their training habits more, compared with HLA, also stopping their training (47.1% vs. 16.1%, respectively). Thus, different training strategies should be designed for HLA and LLA with a normal MC, but this is not so necessary for HLA and LLA who use HC. To sum up, training adaptations should be individually designed according to the training level and use or non-use of HC, always taking into account the pain suffered during the menstrual phase in most of the athletes.Pre-competitive Projects for Early Stage Researchers Program from the University of Granada
PPJIA2020.0
Transcriptome analysis reveals differential splicing events in IPF lung tissue
Idiopathic pulmonary fibrosis (IPF) is a complex disease in which a multitude of proteins and networks are disrupted. Interrogation of the transcriptome through RNA sequencing (RNA-Seq) enables the determination of genes whose differential expression is most significant in IPF, as well as the detection of alternative splicing events which are not easily observed with traditional microarray experiments. We sequenced messenger RNA from 8 IPF lung samples and 7 healthy controls on an Illumina HiSeq 2000, and found evidence for substantial differential gene expression and differential splicing. 873 genes were differentially expressed in IPF (FDR<5%), and 440 unique genes had significant differential splicing events in at least one exonic region (FDR<5%). We used qPCR to validate the differential exon usage in the second and third most significant exonic regions, in the genes COL6A3 (RNA-Seq adjusted pval = 7.18e-10) and POSTN (RNA-Seq adjusted pval = 2.06e-09), which encode the extracellular matrix proteins collagen alpha-3(VI) and periostin. The increased gene-level expression of periostin has been associated with IPF and its clinical progression, but its differential splicing has not been studied in the context of this disease. Our results suggest that alternative splicing of these and other genes may be involved in the pathogenesis of IPF. We have developed an interactive web application which allows users to explore the results of our RNA-Seq experiment, as well as those of two previously published microarray experiments, and we hope that this will serve as a resource for future investigations of gene regulation in IPF. © 2014 Nance et al
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