217 research outputs found
UPC at MediaEval 2014 social event detection task
This document presents the contribution of the UPC team to the Social Event Detection (SED) Subtask 1 in MediaEval 2014. This contribution extends the solution tested in the previous year with a better optimization of the parameters that determine the clustering algorithm, and by introducing an additional pass that considers the merges of all pairs of mini-clusters generated during the two first passes. Our proposal also addresses the problem of incomplete metadata by generating additional textual tags based on geolocation and natural language processing techniques.Postprint (published version
An exponential family of Lorenz curves
A new method for building parametric-functional families of Lorenz curves, generated from an initial Lorenz curve (which satisfies some regularity conditions), is presented. The method is applied to the exponential family since they use the exponential Lorenz curves as their generating curves. Several properties of these families are analyzed, including the population function, inequality measures, and Lorenz orderings. Finally, an application is presented for data from various countries. The family is shown to perform well in fitting the data across countries. The results are very robust across data sources
Use of autoantigen-loaded phosphatidylserine-liposomes to arrest autoimmunity in type 1 diabetes
This is an open access article distributed under the terms of the Creative Commons Attribution License.-- et al.[Introduction]: The development of new therapies to induce self-tolerance has been an important medical health challenge in type 1 diabetes. An ideal immunotherapy should inhibit the autoimmune attack, avoid systemic side effects and allow β-cell regeneration. Based on the immunomodulatory effects of apoptosis, we hypothesized that apoptotic mimicry can help to restore tolerance lost in autoimmune diabetes.[Objective]: To generate a synthetic antigen-specific immunotherapy based on apoptosis features to specifically reestablish tolerance to β-cells in type 1 diabetes.[Methods]: A central event on the surface of apoptotic cells is the exposure of phosphatidylserine, which provides the main signal for efferocytosis. Therefore, phosphatidylserine-liposomes loaded with insulin peptides were generated to simulate apoptotic cells recognition by antigen presenting cells. The effect of antigen-specific phosphatidylserine-liposomes in the reestablishment of peripheral tolerance was assessed in NOD mice, the spontaneous model of autoimmune diabetes. MHC class II-peptide tetramers were used to analyze the T cell specific response after treatment with phosphatidylserine-liposomes loaded with peptides.[Results]: We have shown that phosphatidylserine-liposomes loaded with insulin peptides induce tolerogenic dendritic cells and impair autoreactive T cell proliferation. When administered to NOD mice, liposome signal was detected in the pancreas and draining lymph nodes. This immunotherapy arrests the autoimmune aggression, reduces the severity of insulitis and prevents type 1 diabetes by apoptotic mimicry. MHC class II tetramer analysis showed that peptide-loaded phosphatidylserine-liposomes expand antigen-specific CD4+ T cells in vivo. The administration of phosphatidylserine-free liposomes emphasizes the importance of phosphatidylserine in the modulation of antigen-specific CD4+ T cell expansion.[Conclusions]: We conclude that this innovative immunotherapy based on the use of liposomes constitutes a promising strategy for autoimmune diseases.This work was supported by a grant from Spanish Government (FIS PI12/00195). IPA was supported by AGAUR, Generalitat de Catalunya. MVP and RA are supported by the Health Dept. of the Catalan Government, Generalitat de Catalunya.Peer reviewe
A Novel Liposome-Based Nanocarrier Loaded with an LPS-dsRNA Cocktail for Fish Innate Immune System Stimulation
Development of novel systems of vaccine delivery is a growing demand of the aquaculture industry. Nano- and micro- encapsulation systems are promising tools to achieve efficient vaccines against orphan vaccine fish diseases. In this context, the use of liposomal based-nanocarriers has been poorly explored in fish; although liposomal nanocarriers have successfully been used in other species. Here, we report a new ~125 nm-in-diameter unilamellar liposome-encapsulated immunostimulant cocktail containing crude lipopolysaccharide (LPS) from E. coli and polyinosinic:polycytidylic acid [poly (I:C)], a synthetic analog of dsRNA virus, aiming to be used as a non-specific vaccine nanocarrier in different fish species. This liposomal carrier showed high encapsulation efficiencies and low toxicity not only in vitro using three different cellular models but also in vivo using zebrafish embryos and larvae. We showed that such liposomal LPS-dsRNA cocktail is able to enter into contact with zebrafish hepatocytes (ZFL cell line) and trout macrophage plasma membranes, being preferentially internalized through caveolae-dependent endocytosis, although clathrin-mediated endocytosis in ZFL cells and macropinocytocis in macrophages also contribute to liposome uptake. Importantly, we also demonstrated that this liposomal LPS-dsRNA cocktail elicits a specific pro-inflammatory and anti-viral response in both zebrafish hepatocytes and trout macrophages. The design of a unique delivery system with the ability to stimulate two potent innate immunity pathways virtually present in all fish species represents a completely new approach in fish health
Uniform circular motion in General Relativity: Existence and extendibility of the trajectories
The notion of uniform circular motion in a general spacetime is introduced as a particular
case of a planar motion. The initial value problem of the corresponding di erential
equation is analysed in detail. Geometrically, an observer which obeys a uniform circular
motion is characterized as a Lorentzian helix. The completeness of its inextensible
trajectories is studied in Generalized Robertson-Walker spacetimes and in a relevant family
of pp-wave spacetimes. The results may be physically interpreted saying that, under
reasonable assumptions, a uniformly circular observer lives forever in these spacetimes,
providing the absence of the singularities de ned by these timelike curves
Polyether-block-amide thin-film composite hollow fiber membranes for the recovery of butanol from ABE process by pervaporation
This work reports the continuation of previous efforts to recover butanol from the ABE (acetone-butanol-ethanol) fermentation process by pervaporation (PV). A key aspect to improve the efficiency of the technology is the membrane used to perform the selective butanol separation; hence, this study focuses on the implementation of hollow fiber (HF) membrane configuration for the ABE separation by PV as opposed to flat sheet membrane configuration. The HF membrane preparation was done by dip coating, a frequently used process for the production of HF membranes, which involves the deposition of a thin film of a coating solution. Different thicknesses of the active layer were obtained by modifying the polymer content in the coating solution, allowing later to evaluate the influence of the thickness on the separation performance. This study includes a description of the procedure to prepare selective membranes, its characterization and an analysis of the influence of operating conditions on membrane separation performance. SEM and water contact angle were used to characterize the produced membranes. The mass transport phenomena in the pervaporation process were characterized using a resistances-in-series model. The results allow to adopt a criterion to select the most suitable thickness for the membrane active layer, which allows to achieve an adequate separation performance, and reveal the importance in the choice of the membrane support material. Finally, a comparative analysis of the self-made hollow fiber membranes performance in terms of flux, separation factor and PSI with respect to those found in the literature is presented.This research is being supported by the Spanish AEI under the projects PID2019-104369RB-I00 and RTI2018-093310-B-I00, and by the Project ENERGY PUSH SOE3/P3/E0865, which is co-financed by the European Regional Development Fund (ERPF) in the framework of the INTERREG SUDOE Programme. Carla Arregoitia also thanks for a FPI research scholarship (BES-2017-081708)
Dynamic Simulation Applied to Refinery Hydrogen Networks
[Abstract] This study analyses the usefulness of process network dynamics simulation for decision-making in refinery hydrogen networks. A theoretical hydrogen network of three desulphurisation plants is modelled, and three case scenarios discussed: baseline, high demand, and low demand. Discussion focuses on how the information from the simulation is interpreted and its usefulness for debottlenecking, scheduling and what-if analysis. Stress is put on dynamics of the system and their consequences in process operation throughout the network. Hydrogen purity is highlighted as the most affected variable, and discussed its network wide effect. In addition, the responses of inflows, outflows and headers are analysed. Although the model used is a simplified representation of the actual processes, the simulation analysis showed potential as decision-making support not provided with steady state models. Further researches based on real case-studies should be conducted to better conclude on the efficient usage of simulation in aiding refinery hydrogen networks operational decision
Training Prescription Guided by Heart Rate Variability Vs. Block Periodization in Well-Trained Cyclists
Predefined training programs are common place when prescribing training. Within predefined training, block periodization (BP) has emerged as a popular methodology because of its benefits. Heart rate variability (HRV) has been proposed as an effective tool for prescribing training. The aim of this study is to examine the effect of HRV-guided training against BP in road cycling. Twenty well-trained cyclists participated in this study. After a preliminary baseline period to establish their resting HRV, cyclists were divided into 2 groups: an HRV-guided group and a BP group, and they completed 8 training weeks. Cyclists completed 3 evaluations weeks, before and after each period. During the evaluation weeks, cyclists performed: (a) a graded exercise test to assess V̇O2max, peak power output (PPO), and ventilatory thresholds with their corresponding power output (VT1, VT2, WVT1, and WVT2, respectively) and (b) a 40-minute simulated time-trial (40 TT). The HRV-guided group improved V̇O2max (p 5 0.03), PPO (p 5 0.01), WVT2 (p 5 0.02), WVT1 (p 5 0.01), and 40 TT (p 5 0.04). The BP group improved WVT2 (p 5 0.02). Between-group fitness and performance were similar after the study. The HRV-guided training could lead to a better timing in training prescription than BP in road cycling
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