294 research outputs found
High-Order Numerical Method for 1D Non-local Diffusive Equation
In this paper we present a non-local numerical scheme based on the Local
Discontinuous Galerkin method for a non-local diffusive partial differential
equation with application to traffic flow. In this model, the velocity is
determined by both the average of the traffic density as well as the changes in
the traffic density at a neighborhood of each point. We discuss nonphysical
behaviors that can arise when including diffusion, and our measures to prevent
them in our model. The numerical results suggest that this is an accurate
method for solving this type of equation and that the model can capture desired
traffic flow behavior. We show that computation of the non-local convolution
results in complexity, but the increased computation time
can be mitigated with high-order schemes like the one proposed.Comment: 17 pages and 8 figure
Elevated alanine aminotransferase in blood donors: role of different factors and multiple viral infections.
Many different aetiological agents stimulate alanine aminotransferase (ALT) production. Viral markers and other aetiologies were investigated in 2166 individuals, randomly selected from 10 000 consecutive blood donors. Elevation of ALT was found in 10.8% of subjects. Grouping donors according to ALT level and correlating with, respectively, hepatitis B core antibody (HBcAb), cytomegalovirus antibody alone, or associated with HBcAb, showed similar findings (high ALT 11.1%, normal 11.6%; high 85.4%, normal 81.4%; high 10.2%, normal 11.0%, respectively). Hepatitis C virus (HCV) antibody was found to be significantly associated with elevated ALT levels (high 1.7%, normal 0.26%). Other causes of ALT elevation were alcohol abuse (17%), obesity (25%) and dyslipidaemia (38%), but in 11% there was no obvious aetiology. Although HCV is a rare cause of elevated ALT in blood donors, it seems to be the only virus, among those tested, to account for liver damage. This may be due to the non-protective role of HCV antibody, the low specificity of ALT, or the pathogenic role of uninvestigated viruses
Comparison of the economic impact of different wind power forecast systems for producers
Deterministic forecasts of wind production for the next 72 h at a single
wind farm or at the regional level are among the main end-users requirement.
However, for an optimal management of wind power production and distribution
it is important to provide, together with a deterministic prediction, a
probabilistic one. A deterministic forecast consists of a single value for
each time in the future for the variable to be predicted, while
probabilistic forecasting informs on probabilities for potential future
events. This means providing information about uncertainty (i.e. a forecast
of the PDF of power) in addition to the commonly provided single-valued
power prediction. A significant probabilistic application is related to the
trading of energy in day-ahead electricity markets. It has been shown that,
when trading future wind energy production, using probabilistic wind power
predictions can lead to higher benefits than those obtained by using
deterministic forecasts alone. In fact, by using probabilistic forecasting
it is possible to solve economic model equations trying to optimize the
revenue for the producer depending, for example, on the specific penalties
for forecast errors valid in that market. In this work we have applied a
probabilistic wind power forecast systems based on the "analog ensemble"
method for bidding wind energy during the day-ahead market in the case of a
wind farm located in Italy. The actual hourly income for the plant is
computed considering the actual selling energy prices and penalties
proportional to the unbalancing, defined as the difference between the
day-ahead offered energy and the actual production. The economic benefit of
using a probabilistic approach for the day-ahead energy bidding are
evaluated, resulting in an increase of 23% of the annual income for a
wind farm owner in the case of knowing "a priori" the future energy
prices. The uncertainty on price forecasting partly reduces the economic
benefit gained by using a probabilistic energy forecast system
What kind of hepatitis
Finding one major hepatotropic virus may not be enough to identify the aetiology of liver disease when risk factors are present, particularly in patients with past or present infection with other viral agents, or chronic liver disease. The pathogenic process in these cases is often complex. In the five cases we report, acute hepatitis (initiated by halothane, cytomegalovirus or Epstein-Barr virus) preceded the reactivation of hepatitis B infection, and these events occurred in patients with chronic hepatitis C infection. Each case demonstrates how several viruses can be implicated in the development of hepatitis, either as single agents or via cross-activation of T cells. The nosography of hepatitis, therefore, and the optimum therapeutic choices, can puzzle the clinical team
A Presence- and Performance-Driven Framework to Investigate Interactive Networked Music Learning Scenarios
Cooperative music making in networked environments has been subject of extensive research, scientific and artistic. Networked music performance (NMP) is attracting renewed interest thanks to the growing availability of effective technology and tools for computer-based communications, especially in the area of distance and blended learning applications. We propose a conceptual framework for NMP research and design in the context of classical chamber music practice and learning: presence-related constructs and objective quality metrics are used to problematize and systematize the many factors affecting the experience of studying and practicing music in a networked environment. To this end, a preliminary NMP experiment on the effect of latency on chamber music duos experience and quality of the performance is introduced. The degree of involvement, perceived coherence, and immersion of the NMP environment are here combined with measures on the networked performance, including tempo trends and misalignments from the shared score. Early results on the impact of temporal factors on NMP musical interaction are outlined, and their methodological implications for the design of pedagogical applications are discussed
Sulodexide counteracts endothelial dysfunction induced by metabolic or non-metabolic stresses through activation of the autophagic program
OBJECTIVE: Endothelial dysfunction (ED) predisposes to venous thrombosis (VT) and post-thrombotic syndrome (PTS), a long-term VT-related complication. Sulodexide (SDX) is a highly purified glycosaminoglycan with antithrombotic, pro-fibrinolytic and anti-inflammatory activity used in the treatment of chronic venous disease (CVD), including patients with PTS. SDX has recently obtained clinical evidence in the “extension therapy” after initial-standard anticoagulant treatment for the secondary prevention of recurrent deep vein thrombosis (DVT). Herein, we investigated how SDX counteracts ED. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVEC) were used. Metabolic and non metabolic-induced ED was induced by treating with methylglyoxal (MGO) or irradiation (IR), respectively. Bafilomycin A1 was used to inhibit autophagy. The production of reactive oxygen species (ROS), tetrazolium bromide (MTT) assay for cell viability, terminal de-oxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay for cell apoptosis, Real-time PCR and Western blot analysis for gene and protein expression were used. RESULTS: SDX protected HUVEC from MGO- or IR-induced apoptosis by counteracting the activation of the intrinsic and extrinsic caspase cascades. The cytoprotective effects of SDX resulted from a reduction in a) ROS production, b) neo-synthesis and release of pro-inflammatory cytokines (TNFα, IL1, IL6, IL8), c) DNA damage induced by MGO or IR. These effects were reduced when autophagy was inhibited. CONCLUSIONS: Data herein collected indicate the ability of SDX to counteract ED induced by metabolic or non-metabolic stresses by involving the intracellular autophagy pathway. Our experience significantly increases the knowledge of the mechanisms of action of SDX against ED and supports the use of SDX in the treatment of CVD, PTS and in the secondary prevention of recurrent DVT
Characterisation of large changes in wind power for the day-ahead market using a fuzzy logic approach
Wind power has become one of the renewable resources with a major growth in the electricity market. However, due to its inherent variability, forecasting techniques are necessary for the optimum scheduling of the electric grid, specially during ramp events. These large changes in wind power may not be captured by wind power point forecasts even with very high resolution Numerical Weather Prediction (NWP) models. In this paper, a fuzzy approach for wind power ramp characterisation is presented. The main benefit of this technique is that it avoids the binary definition of ramp event, allowing to identify changes in power out- put that can potentially turn into ramp events when the total percentage of change to be considered a ramp event is not met. To study the application of this technique, wind power forecasts were obtained and their corresponding error estimated using Genetic Programming (GP) and Quantile Regression Forests. The error distributions were incorporated into the characterisation process, which according to the results, improve significantly the ramp capture. Results are presented using colour maps, which provide a useful way to interpret the characteristics of the ramp events
Modeling the impact of sea-spray on particle concentrations in a coastal city
Abstract 18 An atmospheric chemistry-transport model is used to assess the impacts of sea-spray chemistry 19 on the particle composition in and downwind of a coastal city -Vancouver, British Columbia. 20 Reactions in/on sea-spray affect the entire particle ensemble and particularly the size distribution 21 of particle nitrate. 2
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