University of Leon

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    16349 research outputs found

    Combustion of avocado crop residues: varieties and nature of nutrients influence

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    The thermal behaviour of avocado crop residues was studied. The seeds and the pruning remains from Hass and Bacon varieties were analysed to know their fuel properties. The influence of the fertiliser nature was also studied thorough the application of cow manure and inorganic products. Thermogravimetric analysis (TGA) was carried out under 10, 20 and 40 ºC/min heating rates. Kinetics was also estimated according to the Friedman, Flynn-Wall-Ozawa (FWO) and Kissinger- Akahira-Sunose (KAS) methods. Results indicated the good fuel performance of the samples. Higher heating values (HHV) were higher for pruning remains (19.43 MJ/kg) when compared to seeds (18.74 MJ/kg). Cow manure improved the behaviour of all avocado samples regardless of the varieties. Average action energy was lower for wood (143.89 – 211.04 kJ/mol) than seeds (174.05 - 279.99 kJ/mol). Regarding TGA, this analysis showed three different mass loss associated to hemicellulose, cellulose and lignin release. TGA profiles were so different for the different biomass sources according to the fertiliser employed. Hence, the heating rate influenced the thermal behaviour of the samples, highlighting the fast release of the SBC and WHM for the 10 and 20ºC/min ramps respectivelySIF. Lima investigation was conducted within the framework of a predoctoral contract (A.2) under the I Research and Transfer Plan of the University of Málag

    A Comparative Study on Feature Selection for a Risk Prediction Model for Colorectal Cancer

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    [EN]Background and objective: Risk prediction models aim at identifying people at higher risk of developing a target disease. Feature selection is particularly important to improve the prediction model performance avoiding overfitting and to identify the leading cancer risk (and protective) factors. Assessing the stability of feature selection/ranking algorithms becomes an important issue when the aim is to analyze the features with more prediction power. Methods: This work is focused on colorectal cancer, assessing several feature ranking algorithms in terms of performance for a set of risk prediction models (Neural Networks, Support Vector Machines (SVM), Logistic Regression, k-Nearest Neighbors and Boosted Trees). Additionally, their robustness is evaluated following a conventional approach with scalar stability metrics and a visual approach proposed in this work to study both similarity among feature ranking techniques as well as their individual stability. A comparative analysis is carried out between the most relevant features found out in this study and features provided by the experts according to the state-of-the-art knowledge. Results: The two best performance results in terms of Area Under the ROC Curve (AUC) are achieved with a SVM classifier using the top-41 features selected by the SVM wrapper approach (AUC=0.693) and Logistic Regression with the top-40 features selected by the Pearson (AUC=0.689). Experiments showed that performing feature selection contributes to classification performance with a 3.9% and 1.9% improvement in AUC for the SVM and Logistic Regression classifier, respectively, with respect to the results using the full feature set. The visual approach proposed in this work allows to see that the Neural Network-based wrapper ranking is the most unstable while the Random Forest is the most stable. Conclusions: This study demonstrates that stability and model performance should be studied jointly as Random Forest turned out to be the most stable algorithm but outperformed by others in terms of model performance while SVM wrapper and the Pearson correlation coefficient are moderately stable while achieving good model performance. © 2019 Elsevier B.V. All rights reservedS

    Tantalum Alloy Welding: Does the Thermal Cycle Influence the Microstructure?

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    [EN] The aim of the present work is to verify the microstructural behavior of a B 521 tantalum alloy UNS Grade R05200 after welding, in relation to the welding thermal cycle. The joint design was a 1.5 mm thickness circumferential butt welding, on a 32 mm outside diameter pipe, welded in 1 G position (horizontal, flat, and rotating). The chosen welding process was gas tungsten arc welding (GTAW). The microstructural analysis showed the presence of coarse, dendritic-columnar structures, as well as a hexagonal cell, with no cracks noted. Hardness tests showed an increase in hardness, from 120 HV to 425 HV, in the heat-affected zone. Through finite element methods, the behavior of the temperature field was estimated and compared.S

    The effects of scale-up and coal-biomass blending on supercritical coal oxy-combustion power plants

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    [EN] Carbon Capture and Storage (CCS) with biomass is called to be one of the most important technologies to reduce the climate change all over the world. In addition, supercritical pulverized coal plants have been pointed out as interesting power installations because its high efficiency. In this work, the effects of plants scaling and biomass-coal co-firing level on net present value (NPV), cost of energy (COE) and cost of CO2 avoided (CCA) have been studied on a supercritical pulverized combusting coal/biomass blends. Aspen Plus© was used to implement technical simulations. Finally, the main factors affecting plants viability were identified by a sensitivity analysis. The results obtained revealed that the use of biomass reduces the NPV in (-0.23,-1.75) M€/MWe, and increases the COE by (0.007,0.263) M€/MWe. However, plant scaling was found to be a more important factor, by reaching an impact of 4.32M€/MWe on NPV variation in best case. The reduction of oxy-plants viability by biomass using as raw material could be compensated by an increasing of the designed scale-up. Finally, 300 MWe power plants with 40-50% biomass co-firing level were identified as a compromise solution between economy and risk, improving in this way the interest for potential investmentSIThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Authors thanks the assistance of University of Oviedo (Spain) Chemical Engineering Department in the implementation of the technical simulations of this stud

    Impact of resistance training on the autophagy-inflammation-apoptosis crosstalk in elderly subjects

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    [EN]Aging is associated with a decline in autophagy and a state of low-grade inflammation which further affects apoptosis and autophagy. Importantly, these alterations could reverse with regular physical activity. This study assessed the effects of a resistance exercise training program on autophagy, NLRP3 inflammasome, and apoptosis in peripheral blood mononuclear cells (PBMCs) from old subjects. Twenty-six healthy women and men (age, 69.6±1.5 yr) were randomized to a training (TG) or a control (CG) group. TG performed an 8-week resistance training program, while CG followed their daily routines. Protein expression of beclin-1, Atg12, Atg16 and LAMP-2 increased following the training program, while expression of p62/SQSTM1 and phosphorylation of ULK-1 at Ser757 were significantly lower. Resistance exercise also induced a decrease in NLRP3 expression and in the caspase-1/procaspase-1 ratio. Expression of Bcl-2 and Bcl-xL, as well as the Bad/BcL-2 ratio were reduced, and there was a significant decrease in the protein content of caspase-3. The results obtained seem to indicate that 8-week resistance training stimulates autophagy, prevents NLRP3 inflammasome activation, and reduces apoptosis in PBMCs from elderly subjects. These data could have a significant impact in prevention and rehabilitation programs currently employed in elderly population.S

    An analysis and enhanced proposal of atmospheric boundary layer wind modelling techniques for automation of air traffic management

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    Production and hosting by Elsevier[EN] The air traffic management automation imposes stringent requirements on the weather models, in such a way that they should be able to provide reliable short-time forecasts in digital formats in almost real time. The atmospheric boundary layer is one of the regions where aircraft operation and coordination are critical and therefore atmospheric model performance is also vital. This paper presents conventional and innovative techniques to improve the accuracy in the forecasting of winds in the lower atmospheric layer, proposing mechanisms to develop better models including deterministic and stochastic simulations. Accuracy is improved by optimizing the grid, assimilating observations in cycling simulations and managing a number of ensemble members. An operation-driven post-processing stage helps to incorporate detailed terrain definitions and real-time observations without re-running the model. The improvements are checked against mesoscale weather simulations at different scales and a dedicated flight campaign. The results show good performance of the model without sensitively increasing the required throughput.SIBoeing Research & Technology Europ

    Ivermectin inhibits ovine ABCG2-mediated in vitro transport of meloxicam and reduces its secretion into milk in sheep

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    [EN] The ATP-binding cassette transporter G2 (ABCG2) is an efflux protein involved in the bioavailability and secretion into milk of several compounds including anti inflammatory drugs. The aim of this work was to determine the effect in sheep of an ABCG2 inhibitor, such as the macrocyclic lactone ivermectin, on the secretion into milk of meloxicam, a non-steroidal anti-inflammatory drug widely used in veterinary medicine, and recently reported as an ABCG2 substrate. In vitro meloxicam transport assays in ovine ABCG2-transduced cells have shown that ivermectin is an efficient inhibitor of in vitro transport of meloxicam mediated by ovine ABCG2, with a 75% inhibition in the transport ratio (24.85 ± 4.62 in controls vs 6.31 ± 1.37 in presence of ivermectin). In addition, the role of ovine ABCG2 in secretion into milk of meloxicam was corroborated using Assaf lactating sheep coadministered with ivermectin. Animals were administered subcutaneously with meloxicam (0.5 mg/kg) with or without ivermectin (0.2 mg/kg). No difference in plasma pharmacokinetic parameters was found between treatments. In the case of milk, a significant reduction in the area under concentration-time curve (AUC) (3.92 ± 0.66 vs 2.26 ± 1.52 vs μg·h/mL) and the AUC milk-to-plasma ratio (0.17 ± 0.03 vs 0.09 ± 0.06) was reported for ivermectin-treated animals compared to controls.SIThis work was supported by the research projects AGL2015-65626-R (MCIN/AEI/10.13039/501100011033/FEDER” Una manera de hacer Europa”) and RTI2018-100903-B-I00 (MCIN/AEI/10.13039/501100011033/FEDER” Una manera de hacer Europa”); and by the predoctoral grants (FPU18/01559 grant to EBP, FPU19/04169 grant to LAF) from the Spanish Ministry of Education, Culture and Sport and BES-2016-077235 grant to AMGL (MCIN/AEI/10.13039/501100011033 y FSE ”El FSE invierte en tu futuro”). We are grateful to Prof. James McCue for assistance with language editing

    The effect of match fatigue in elite badminton players using plantar pressure measurements and the implications to injury mechanisms

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    [EN] The purpose of this study was to investigate the differences in plantar pressure under the lead and trail foot between two lunge tasks to the net in the dominant (LD) and non-dominant (LND) directions, and to explore how fatigue affects the plantar pressure patterns whilst performing movements before and after a competitive match. Peak and mean pressure were measured with the Biofoot-IBV in-shoe system from five repetitions of each task, with sensors positioned under the calcaneus, midfoot and phalanges on the lead and trail foot. Data were collected pre and immediately post playing an official 1st national league competition match. The study was conducted with a sample of thirteen 1st league badminton players. A 2x2 repeated ANOVA found significant differences between the two tasks and between pre and post match (fatigued state). Players also had different foot pressure distributions for the LD and LND tasks, which indicated a difference in loading strategy. In a fatigued state the plantar pressure shifted to the medial aspect of the midfoot in the trail limb, indicating a reduction in control and a higher injury risk during non-dominant lunge tasks.SIGeneralitat Valenciana ACIF121/2015Universidad Católica de Valencia San Vicente Márti

    Towards a network place branding through multiple stakeholders and based on cultural identities

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    [EN] Purpose: This paper aims to analyse the o-eation of a place brand for Colombia's coffee region, within the framework of the evolution of place branding from traditional, one institution-led marketing approaches towards a more modem concept of network branding involving multiple stakeholders. The production of quality coffee in this region has been complemented with the development of coffee-themed rural tourism, which helps Colombia to enhance the value and positionings of its resources in the context of the economic and cultural exchanges inherent in globalisation. Design/methodology/approach: Following a theoretical and conceptual analysis of place branding, this paper explores the case of the Coffee Triangle, examining the network of interrelationships involved in the process ofbusiness-led coffee branding and place branding by public institutions to achieve a dynamic identity asset shared by various parties. This study entailed fieldwork in Colombia to visit the region and hold meetings with managers in public administration, representative companies in the region and various social groups and entities. Findings: Following a conceptual analysis which attempts to demonstrate the evolution of place branding towards a more holistic, multi-party and networked approach, the case study confirms the formation of complex interactions between stakeholders and public and private institutions at the local, regional, national and even international leve!. Practical/implications: This successful initiative can serve as an example for other food production regions in emerging countries, helping them to improve their positions in global scenarios and enhance the value of their physical products through a heightened awareness and appreciation of the culture associated with these natural environments and landscapes. Synergies between business and place branding are also analysed. Originality/value: This paper looks at an instance of place branding involving multiple stakeholders and on the basis of cultural and dynamic identity. It comprises an ínter-regional case study in Colombia. South America is a sub-continent where sorne interesting and successful place projects are being implemented that add nuances to global economic and cultural dialogue, which has probably focused mainly on the Western world and the industrial nations of Asia.S

    Heart Disease, Now What? Improving Quality of Life through Education

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    Introduction: The management of chronic illness assumes a level of demand for permanent care and reaches a priority dimension in the health context. Given the importance of nursing care to post-acute coronary syndrome patients, the objective of this study is to evaluate the impact of an educational intervention program on quality of life in patients after acute coronary syndrome. Method: Quasi-experimental study with two groups: an experimental group exposed to the educational intervention program and the control group without exposure to the educational intervention program. Results: The results showed statistically significant differences between both groups (p < 0.001). Although only valid for the specific group of subjects studied, the educational intervention program enabled significant gains in quality of life. Conclusions: According to the findings of the study, a systematized and structured educational program, integrated into the care organization and based on transition processes, is effective in developing self-care skills and improves the quality of life in patients after acute coronary syndrome.S


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