Search results for: Angel Pérez Sánchez
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 466

Search results for: Angel Pérez Sánchez

376 Association of Leptin Gene T3469C Polymorphism on Reproductive Performance of Purebred Sows

Authors: Mariedel Autriz, Angel Lambio, Renato Vega, Severino Capitan, Rita Laude

Abstract:

The study was conducted to associate genetic polymorphism of the leptin gene T3469C with reproductive performance in purebred sows. DNA were isolated from hair follicles of 29 Landrace and 24 Large White sows. Amplification of the leptin gene was done followed by Hinf1digestion to determine the base at the T3469C site. Electrophoresis of the digestion products revealed that there were 25 Landrace and 15 Large White sows with the TT genotype while there were 3 Landrace and 6 Large White TC. There was 1 CC for Landrace and 3 for Large White. Significant genotype associations were observed for total litter size born and total born alive. Significant breed differences, on the other hand, was observed for gestation length and average birth weight. Significant breed by genotype interaction was observed in litter size total born and litter size born alive.

Keywords: genetic polymorphism, leptin, swine, T3469C

Procedia PDF Downloads 391
375 Static Light Scattering Method for the Analysis of Raw Cow's Milk

Authors: V. Villa-Cruz, H. Pérez-Ladron de Guevara, J. E. Diaz-Díaz

Abstract:

Static Light Scattering (SLS) was used as a method to analyse cow's milk raw, coming from the town of Lagos de Moreno, Jalisco, Mexico. This method is based on the analysis of the dispersion of light laser produced by a set of particles in solution. Based on the above, raw milk, which contains particles of fat globules, with a diameter of 2000 nm and particles of micelles of protein with 300 nm in diameter were analyzed. For this, dilutions of commercial milk were made (1.0%, 2.0% and 3.3%) to obtain a pattern of laser light scattering and also made measurements of raw cow's milk. Readings were taken in a sweep initial angle 10° to 170°, results were analyzed with the program OriginPro 7. The SLS method gives us an estimate of the percentage of fat content in milk samples. It can be concluded that the SLS method, is a quick method of analysis to detect adulteration in raw cow's milk.

Keywords: light scattering, milk analysis, adulteration in milk, micelles, OriginPro

Procedia PDF Downloads 346
374 Argon/Oxygen Plasma Surface Modification of Biopolymers for Improvement of Wettability and Wear Resistance

Authors: Binnur Sagbas

Abstract:

Artificial joint replacements such as total knee and total hip prosthesis have been applied to the patients who affected by osteoarthritis. Although different material combinations are used for these joints, biopolymers are most commonly preferred materials especially for acetabular cup and tibial component of hip and knee joints respectively. The main limitation that shortens the service life of these prostheses is wear. Wear is complicated phenomena and it must be considered with friction and lubrication. In this study, micro wave (MW) induced argon+oxygen plasma surface modification were applied on ultra-high molecular weight polyethylene (UHMWPE) and vitamin E blended UHMWPE (VE-UHMWPE) biopolymer surfaces to improve surface wettability and wear resistance of the surfaces. Contact angel measurement method was used for determination of wettability. Ball-on-disc wear test was applied under 25% bovine serum lubrication conditions. The results show that surface wettability and wear resistance of both material samples were increased by plasma surface modification.

Keywords: artificial joints, plasma surface modification, UHMWPE, vitamin E, wear

Procedia PDF Downloads 277
373 Barriers to Innovation Based on Environmentally Friendly Technology Adoption in Developing Countries: The Case of Production in Rural Areas in Cauca-Colombia

Authors: Deycy Janeth Sanchez Preciado, Bjorn Claes, Paola Andrade

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The development of appropriate environmentally friendly technologies has aided communities in rural areas in emerging economies to better use their natural resources, increase productivity while reducing pollution. Moreover, it has improved their innovation capabilities and ability to develop products for new markets. However, despite the advances, the adoption of these technologies is not generalized and does not always show the expected benefits for the communities and other actors involved in the co-creation process. In this paper, we study the barriers that inhibit the adoption of technologies to reach innovation levels and study comparative cases in rural areas of Cauca in Colombia. We develop and test a theory grounded framework, and we compile an overview of the most important of barriers.

Keywords: technology adoption, environmentally friendly technology, developing countries, rural production, innovation, appropriate technology

Procedia PDF Downloads 188
372 Not Suitable for Repatriation nor Refugee Status: How Undocumented Immigrant Women Survives Street Policing

Authors: Angel Mabudusha

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The impression created by the high volume of foreign nationals being deported by the South African Home Affairs and the police departments is that all undocumented foreign nationals insist on staying in South Africa and voluntary repatriation is open for every person. However, those foreign nationals whose request for deportation has been rejected are often not reported on especially their everyday survival as undocumented immigrant women and their encounter with the police on the street. As a result, this paper aims at exploring the everyday experiences of these women on the street and on why the number of undocumented immigrant women in this country will remain a challenge to the police department. The research was conducted in two cities in South Africa, namely: Johannesburg and Pretoria where the police, the undocumented immigrant women, the human rights lawyers and NGO officials were interviewed on this matter. Based on the idea that voluntary repatriation is open for every immigrant, this study has found that some women’ request for voluntary repatriation remain a dream that never came true. Furthermore, this article proposes more humanitarian ways of dealing with undocumented immigrant women.

Keywords: repatriation, refugee status, undocumented foreign nationals, humanitarian

Procedia PDF Downloads 395
371 Human Error Analysis in the USA Marine Accidents Reports

Authors: J. Sánchez-Beaskoetxea

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The analysis of accidents, such as marine accidents, is one of the most useful instruments to avoid future accidents. In the case of marine accidents, from a simple collision of a small boat in a port to the wreck of a gigantic tanker ship, the study of the causes of the accidents is the basis of a great part of the marine international legislation. Some countries have official institutions who investigate all the accidents in which a ship with their flag is involved. In the case of the USA, the National Transportation Safety Board (NTSB) is responsible for these researches. The NTSB, after a deep investigation into each accident, publishes a Marine Accident Report with the possible cause of the accident. This paper analyses all the Marine Accident Reports published by the NTBS and focuses its attention especially in the Human Errors that led to reported accidents. In this research, the different Human Errors made by crew members are cataloged in 10 different groups. After a complete analysis of all the reports, the statistical analysis on the Human Errors typology in marine accidents is presented in order to use it as a tool to avoid the same errors in the future.

Keywords: human error, marine accidents, ship crew, USA

Procedia PDF Downloads 391
370 WHSS: A Platform for Designing Water Harvesting Systems for Multiple Purposes

Authors: Ignacio Sanchez Cohen, Aurelio Pedroza Sandoval, Ricardo Trejo Calzada

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Water harvesting systems (WHS) has become the unique alternative that farmers in dry areas accounts for surviving dry periods. Nevertheless, technicians, agronomists, and users, in general, have to cope with the difficulty of finding suitable technology for optimal design of WHS. In this paper, we describe a user-friendly computer program that uses readily available information for the design of multiple WHS depending upon the water final use (agriculture, household, conservation, etc). The application (APP) itself contains several links to help the user complete the input requirements. It is not a prerequisite to have any computer skills for the use of the APP. Outputs of the APP are the dimensions of the WHS named terraces, micro-catchments, cisterns, and small household cisterns for roof water catchment. The APP also provides guidance on crops for backyard agriculture. We believe that this tool may guide users to better optimize WHS for multiple purposes and to widen the possibility of copping with dry spells in arid lands.

Keywords: rainfall-catchment, models, computer aid, arid lands

Procedia PDF Downloads 149
369 Antimicrobial Activity of Biosynthesized Silver Nanoparticles with Handroanthus Chrysanthus Flower Extract

Authors: Eduardo Padilla, Luis Daniel Rodriguez, Ivan Sanchez, Angelica Sofia Go

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The synthesis and application of metallic nanoparticles have increased in recent years. Biological methods go beyond the chemical and physical synthesis that is expensive and not friendly to the environment. Therefore, in this study, silver nanoparticles were synthesized biologically in an environmentally friendly way by Handroanthus chrysanthus flower aqueous extract (AgNPs) that contains phytochemicals capable of reducing silver nitrate. AgNPs were characterized visually by UV-visible spectroscopy and TEM. The antimicrobial activity of the AgNPs was tested by determining the minimum inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) in Escherichia coli and Staphylococcus aureus strains AgNPs showed potent antimicrobial activity against gram-negative and gram-positive bacteria. MIC and MBC values were as low as 41.6, and 83.2 ug/mL using AgNPs biosynthesized by H. chrysanthus flower extract. This nanoparticle could be the basis for the formulation of disinfectants for use in the food and pharmaceutical industry.

Keywords: antimicrobial, silver nanoparticles, flower extract, Handroanthus

Procedia PDF Downloads 71
368 Exploring the Landscape of Information Visualization through a Mark Lombardi Lens

Authors: Alon Friedman, Antonio Sanchez Chinchon

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This bibliometric study takes an artistic and storytelling approach to explore the term ”information visualization.” Analyzing over 1008 titles collected from databases that specialize in data visualization research, we examine the titles of these publications to report on the characteristics and development trends in the field. Employing a qualitative methodology, we delve into the titles of these publications, extracting leading terms and exploring the cooccurrence of these terms to gain deeper insights. By systematically analyzing the leading terms and their relationships within the titles, we shed light on the prevailing themes that shape the landscape of ”information visualization” by employing the artist Mark Lombardi’s techniques to visualize our findings. By doing so, this study provides valuable insights into bibliometrics visualization while also opening new avenues for leveraging art and storytelling to enhance data representation.

Keywords: bibliometrics analysis, Mark Lombardi design, information visualization, qualitative methodology

Procedia PDF Downloads 51
367 Students’ Experiential Knowledge Production in the Teaching-Learning Process of Universities

Authors: Didiosky Benítez-Erice, Frederik Questier, Dalgys Pérez-Luján

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This paper aims to present two models around the production of students’ experiential knowledge in the teaching-learning process of higher education: the teacher-centered production model and the student-centered production model. From a range of knowledge management and experiential learning theories, the paper elaborates into the nature of students’ experiential knowledge and proposes further adjustments of existing second-generation knowledge management theories taking into account the particularities of higher education. Despite its theoretical nature the paper can be relevant for future studies that stress student-driven improvement and innovation at higher education institutions.

Keywords: experiential knowledge, higher education, knowledge management, teaching-learning process

Procedia PDF Downloads 419
366 Expected Present Value of Losses in the Computation of Optimum Seismic Design Parameters

Authors: J. García-Pérez

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An approach to compute optimum seismic design parameters is presented. It is based on the optimization of the expected present value of the total cost, which includes the initial cost of structures as well as the cost due to earthquakes. Different types of seismicity models are considered, including one for characteristic earthquakes. Uncertainties are included in some variables to observe the influence on optimum values. Optimum seismic design coefficients are computed for three different structural types representing high, medium and low rise buildings, located near and far from the seismic sources. Ordinary and important structures are considered in the analysis. The results of optimum values show an important influence of seismicity models as well as of uncertainties on the variables.

Keywords: importance factors, optimum parameters, seismic losses, seismic risk, total cost

Procedia PDF Downloads 262
365 Improvement of the Traditional Techniques of Artistic Casting through the Development of Open Source 3D Printing Technologies Based on Digital Ultraviolet Light Processing

Authors: Drago Diaz Aleman, Jose Luis Saorin Perez, Cecile Meier, Itahisa Perez Conesa, Jorge De La Torre Cantero

Abstract:

Traditional manufacturing techniques used in artistic contexts compete with highly productive and efficient industrial procedures. The craft techniques and associated business models tend to disappear under the pressure of the appearance of mass-produced products that compete in all niche markets, including those traditionally reserved for the work of art. The surplus value derived from the prestige of the author, the exclusivity of the product or the mastery of the artist, do not seem to be sufficient reasons to preserve this productive model. In the last years, the adoption of open source digital manufacturing technologies in small art workshops can favor their permanence by assuming great advantages such as easy accessibility, low cost, and free modification, adapting to specific needs of each workshop. It is possible to use pieces modeled by computer and made with FDM (Fused Deposition Modeling) 3D printers that use PLA (polylactic acid) in the procedures of artistic casting. Models printed by PLA are limited to approximate minimum sizes of 3 cm, and optimal layer height resolution is 0.1 mm. Due to these limitations, it is not the most suitable technology for artistic casting processes of smaller pieces. An alternative to solve size limitation, are printers from the type (SLS) "selective sintering by laser". And other possibility is a laser hardens, by layers, metal powder and called DMLS (Direct Metal Laser Sintering). However, due to its high cost, it is a technology that is difficult to introduce in small artistic foundries. The low-cost DLP (Digital Light Processing) type printers can offer high resolutions for a reasonable cost (around 0.02 mm on the Z axis and 0.04 mm on the X and Y axes), and can print models with castable resins that allow the subsequent direct artistic casting in precious metals or their adaptation to processes such as electroforming. In this work, the design of a DLP 3D printer is detailed, using backlit LCD screens with ultraviolet light. Its development is totally "open source" and is proposed as a kit made up of electronic components, based on Arduino and easy to access mechanical components in the market. The CAD files of its components can be manufactured in low-cost FDM 3D printers. The result is less than 500 Euros, high resolution and open-design with free access that allows not only its manufacture but also its improvement. In future works, we intend to carry out different comparative analyzes, which allow us to accurately estimate the print quality, as well as the real cost of the artistic works made with it.

Keywords: traditional artistic techniques, DLP 3D printer, artistic casting, electroforming

Procedia PDF Downloads 118
364 MRI Compatible Fresnel Zone Plates made of Polylactic Acid

Authors: Daniel Tarrazó-Serrano, Sergio Pérez-López, Sergio Castiñeira-Ibáñez, Pilar Candelas, Constanza Rubio

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Zone Plates (ZPs) are used in many areas of physics where planar fabrication is advantageous in comparison with conventional curved lenses. There are several types of ZPs, such as the well-known Fresnel ZPs or the more recent Fractal ZPs and Fibonacci ZPs. The material selection of the lens plays a very important role in the beam modulation control. This work presents a comparison between two Fresnel ZP made from different materials in the ultrasound domain: Polylactic Acid (PLA) and brass. PLA is the most common material used in commercial 3D-printers due to its high design flexibility and low cost. Numerical simulations based on Finite Element Method (FEM) and experimental results are shown, and they prove that the focusing capabilities of brass ZPs and PLA ZPs are similar. For this reason, PLA is proposed as a Magnetic Resonance Imaging (MRI) compatible material with great potential for therapeutic ultrasound focusing applications.

Keywords: FZP, PLA, focus, ultrasound, MRI

Procedia PDF Downloads 176
363 Optimal Mitigation of Slopes by Probabilistic Methods

Authors: D. De-León-Escobedo, D. J. Delgado-Hernández, S. Pérez

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A probabilistic formulation to assess the slopes safety under the hazard of strong storms is presented and illustrated through a slope in Mexico. The formulation is based on the classical safety factor (SF) used in practice to appraise the slope stability, but it is introduced the treatment of uncertainties, and the slope failure probability is calculated as the probability that SF<1. As the main hazard is the rainfall on the area, statistics of rainfall intensity and duration are considered and modeled with an exponential distribution. The expected life-cycle cost is assessed by considering a monetary value on the slope failure consequences. Alternative mitigation measures are simulated, and the formulation is used to get the measures driving to the optimal one (minimum life-cycle costs). For the example, the optimal mitigation measure is the reduction on the slope inclination angle.

Keywords: expected life-cycle cost, failure probability, slopes failure, storms

Procedia PDF Downloads 129
362 Forecast Based on an Empirical Probability Function with an Adjusted Error Using Propagation of Error

Authors: Oscar Javier Herrera, Manuel Angel Camacho

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This paper addresses a cutting edge method of business demand forecasting, based on an empirical probability function when the historical behavior of the data is random. Additionally, it presents error determination based on the numerical method technique ‘propagation of errors’. The methodology was conducted characterization and process diagnostics demand planning as part of the production management, then new ways to predict its value through techniques of probability and to calculate their mistake investigated, it was tools used numerical methods. All this based on the behavior of the data. This analysis was determined considering the specific business circumstances of a company in the sector of communications, located in the city of Bogota, Colombia. In conclusion, using this application it was possible to obtain the adequate stock of the products required by the company to provide its services, helping the company reduce its service time, increase the client satisfaction rate, reduce stock which has not been in rotation for a long time, code its inventory, and plan reorder points for the replenishment of stock.

Keywords: demand forecasting, empirical distribution, propagation of error, Bogota

Procedia PDF Downloads 591
361 Improvement of Protein Extraction From Shrimp by Product Used for Electrospinning by Applying Emerging Technologies

Authors: Mario Pérez-Won, Vilbett Briones L., Guido Trautmann, María José Bugueño, Gipsy Tabilo-Munizaga, Luis Gonzalez-Cavieres

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The fishing industry generates a significant amount of shrimp byproducts, which often result in environmental contamination. Protein extraction from these by-products is a potential solution to minimize waste and revalue the by-products. To improve the extraction of proteins (by chemical method) from shrimp (Pleuroncodes monodon) by-products, the emerging technologies of ohmic heating (OH), microwaves (MW) and pulsed electric fields (PEF) were used. The results show that microwaves, electrical pulses, and ohmic heating improved performance by 28.19%, 19.25%, and 3.65%, respectively. Furthermore, conformational changes were studied by DSC and FTIR. Subsequently, the use of these proteins in electrospinning technology was evaluated. In conclusion, this study demonstrates that the application of emerging technologies, can significantly improve the extraction yield of proteins from shrimp by-products.

Keywords: electrospinning, emerging technologies, improving extraction, shrimp by-products

Procedia PDF Downloads 46
360 Heavy Metals Estimation in Coastal Areas Using Remote Sensing, Field Sampling and Classical and Robust Statistic

Authors: Elena Castillo-López, Raúl Pereda, Julio Manuel de Luis, Rubén Pérez, Felipe Piña

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Sediments are an important source of accumulation of toxic contaminants within the aquatic environment. Bioassays are a powerful tool for the study of sediments in relation to their toxicity, but they can be expensive. This article presents a methodology to estimate the main physical property of intertidal sediments in coastal zones: heavy metals concentration. This study, which was developed in the Bay of Santander (Spain), applies classical and robust statistic to CASI-2 hyperspectral images to estimate heavy metals presence and ecotoxicity (TOC). Simultaneous fieldwork (radiometric and chemical sampling) allowed an appropriate atmospheric correction to CASI-2 images.

Keywords: remote sensing, intertidal sediment, airborne sensors, heavy metals, eTOCoxicity, robust statistic, estimation

Procedia PDF Downloads 383
359 The Influence of National Culture on Business Negotiations: An Exploratory Study of Venezuelan and British Managers

Authors: Mohamed Haffar, Loredana Perez

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Significant attention has recently been paid to the cross-cultural negotiations due to the growth of international businesses. Despite the substantial body of literature examining the influence of national culture (NC) dimensions on negotiations, there is a lack of studies comparing the influence of NC in Latin America with a Western European countries, In particular, an extensive review of the literature revealed that a contribution to knowledge would be derived from the comparison of the influence of NC dimensions on negotiations in UK and Venezuela. The primary data was collected through qualitative interviews, to obtain an insight about the perceptions and beliefs of Venezuelan and British business managers about their negotiating styles. The findings of this study indicated that NC has a great influence on the negotiating styles. In particular, Venezuelan and British managers demonstrated to have opposed negotiating styles, affecting the way they communicate, approach people and their willingness to take risks.

Keywords: national culture, negotiation, international business, Venezula, UK

Procedia PDF Downloads 441
358 Mathematical Modelling of the Effect of Glucose on Pancreatic Alpha-Cell Activity

Authors: Karen K. Perez-Ramirez, Genevieve Dupont, Virginia Gonzalez-Velez

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Pancreatic alpha-cells participate on glucose regulation together with beta cells. They release glucagon hormone when glucose level is low to stimulate gluconeogenesis from the liver. As other excitable cells, alpha cells generate Ca2+ and metabolic oscillations when they are stimulated. It is known that the glucose level can trigger or silence this activity although it is not clear how this occurs in normal and diabetic people. In this work, we propose an electric-metabolic mathematical model implemented in Matlab to study the effect of different glucose levels on the electrical response and Ca2+ oscillations of an alpha cell. Our results show that Ca2+ oscillations appear in opposite phase with metabolic oscillations in a window of glucose values. The model also predicts a direct relationship between the level of glucose and the intracellular adenine nucleotides showing a self-regulating pathway for the alpha cell.

Keywords: Ca2+ oscillations, mathematical model, metabolic oscillations, pancreatic alpha cell

Procedia PDF Downloads 148
357 Effects of Medium Composition on the Production of Biomass and a Carbohydrate Isomerase by a Novel Strain of Lactobacillus

Authors: M. Miriam Hernández-Arroyo, Ivonne Caro-Gonzales, Miguel Ángel Plascencia-Espinosa, Sergio R. Trejo-Estrada

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A large biodiversity of Lactobacillus strains has been detected in traditional foods and beverages from Mexico. A selected strain of Lactobacillus sp - PODI-20, used for the obtained from an artisanal fermented beverage was cultivated in different carbon sources in a complex medium, in order to define which carbon sourced induced more effectively the isomerization of arabinose by cell fractions obtained by fermentation. Four different carbon sources were tested in a medium containing peptone and yeast extract and mineral salts. Glucose, galactose, arabinose, and lactose were tested individually at three different concentrations: 3.5, 6, and 10% w/v. The biomass yield ranged from 1.72 to 17.6 g/L. The cell pellet was processed by mechanical homogenization. Both fractions, the cellular debris, and the lysis supernatant were tested for their ability to isomerize arabinose into ribulose. The highest yield of isomer was 12 % of isomerization in the supernatant fractions; whereas up to 9.3% was obtained by the use of cell debris. The isomerization of arabinose has great significance in the production of lactic acid by fermentation of complex carbohydrate hydrolysates.

Keywords: isomerase, tagatose, aguamiel, isomerization

Procedia PDF Downloads 316
356 An Exploratory Study of the Student’s Learning Experience by Applying Different Tools for e-Learning and e-Teaching

Authors: Angel Daniel Muñoz Guzmán

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E-learning is becoming more and more common every day. For online, hybrid or traditional face-to-face programs, there are some e-teaching platforms like Google classroom, Blackboard, Moodle and Canvas, and there are platforms for full e-learning like Coursera, edX or Udemy. These tools are changing the way students acquire knowledge at schools; however, in today’s changing world that is not enough. As students’ needs and skills change and become more complex, new tools will need to be added to keep them engaged and potentialize their learning. This is especially important in the current global situation that is changing everything: the Covid-19 pandemic. Due to Covid-19, education had to make an unexpected switch from face-to-face courses to digital courses. In this study, the students’ learning experience is analyzed by applying different e-tools and following the Tec21 Model and a flexible and digital model, both developed by the Tecnologico de Monterrey University. The evaluation of the students’ learning experience has been made by the quantitative PrEmo method of emotions. Findings suggest that the quantity of e-tools used during a course does not affect the students’ learning experience as much as how a teacher links every available tool and makes them work as one in order to keep the student engaged and motivated.

Keywords: student, experience, e-learning, e-teaching, e-tools, technology, education

Procedia PDF Downloads 82
355 Epigenetic Mechanisms Involved in the Occurrence and Development of Infectious Diseases

Authors: Frank Boris Feutmba Keutchou, Saurelle Fabienne Bieghan Same, Verelle Elsa Fogang Pokam, Charles Ursula Metapi Meikeu, Angel Marilyne Messop Nzomo, Ousman Tamgue

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Infectious diseases are one of the most important causes of morbidity and mortality worldwide. These diseases are caused by micro-pathogenic organisms, such as bacteria, viruses, parasites, and fungi. Heritable changes in gene expression that do not involve changes to the underlying DNA sequence are referred to as epigenetics. Emerging evidence suggests that epigenetic mechanisms are important in the emergence and progression of infectious diseases. Pathogens can manipulate host epigenetic machinery to promote their own replication and evade immune responses. The Human Genome Project has provided new opportunities for developing better tools for the diagnosis and identification of target genes. Several epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA expression, have been shown to influence infectious disease outcomes. Understanding the epigenetic mechanisms underlying infectious diseases may result in the progression of new therapeutic approaches focusing on host-pathogen interactions. The goal of this study is to show how different infectious agents interact with host cells after infection.

Keywords: epigenetic, infectious disease, micro-pathogenic organism, phenotype

Procedia PDF Downloads 52
354 Magnetic Properties and Cytotoxicity of Ga-Mn Magnetic Ferrites Synthesized by the Citrate Sol-Gel Method

Authors: Javier Sánchez, Laura Elena De León Prado, Dora Alicia Cortés Hernández

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Magnetic spinel ferrites are materials that possess size, magnetic properties and heating ability adequate for their potential use in biomedical applications. The Mn0.5Ga0.5Fe2O4 magnetic nanoparticles (MNPs) were synthesized by sol-gel method using citric acid as chelating agent of metallic precursors. The synthesized samples were identified by X-Ray Diffraction (XRD) as an inverse spinel structure with no secondary phases. Saturation magnetization (Ms) of crystalline powders was 45.9 emu/g, which was higher than those corresponding to GaFe2O4 (14.2 emu/g) and MnFe2O4 (40.2 emu/g) synthesized under similar conditions, while the coercivity field (Hc) was 27.9 Oe. The average particle size was 18 ± 7 nm. The heating ability of the MNPs was enough to increase the surrounding temperature up to 43.5 °C in 7 min when a quantity of 4.5 mg of MNPs per mL of liquid medium was tested. Cytotoxic effect (hemolysis assay) of MNPs was determined and the results showed hemolytic values below 1% in all tested cases. According to the results obtained, these synthesized nanoparticles can be potentially used as thermoseeds for hyperthermia therapy.

Keywords: manganese-gallium ferrite, magnetic hyperthermia, heating ability, cytotoxicity

Procedia PDF Downloads 363
353 Discouraged Borrowers: Evidence for Eurozone SMEs

Authors: Javier Sanchez Vidal, Ciarán Mac An Bhaird, Brian Lucey

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This study examines the decision by firm owners not to apply for intermediated debt due to a perception that their application will be rejected. Based on a sample of SMEs in 9 European countries over the period 2009-2011, we examine potential explanatory factors for borrower discouragement, including firm, macroeconomic, regulatory and banking industry variables. Compared with firms that applied for bank loans, discouraged borrowers are smaller, younger, have declining turnover and an increasing debt/assets ratio. Perceived willingness of banks to lend rather than the company’s own credit history is more important to encourage applications. Perceptions of refusal are procyclical and may be self-perpetuating. Increased concentration in the banking sector reduces discouragement, indicating the importance of relationship banking. Transmission of macro effects through the banking system and economic environment may also lead to higher levels of discouragement. A good regulatory scheme is also advisable, either for the lenders or the borrowers (overall the good ones).

Keywords: entrepreneurial finance, discouraged borrowers, banking, financial crisis, eurozone

Procedia PDF Downloads 375
352 Pulsed Electric Field as Pretreatment for Different Drying Method in Chilean Abalone (Concholepas Concholepas) Mollusk: Effects on Product Physical Properties and Drying Methods Sustainability

Authors: Luis González-Cavieres, Mario Perez-Won, Anais Palma-Acevedo, Gipsy Tabilo-Munizaga, Erick Jara-Quijada, Roberto Lemus-Mondaca

Abstract:

In this study, pulsed electric field (PEF: 2.0 kV/cm) was used as pretreatment in drying methods, vacuum microwave (VMD); freeze-drying (FD); and hot air (HAD), in Chilean abalone mollusk. Drying parameters, quality, energy consumption, and Sustainability parameters were evaluated. PEF+VMD showed better values than the other drying systems, with drying times 67% and 83% lower than PEF+FD and FD. In the quality parameters, PEF+FD showed a significantly lower value for hardness (250 N), and a lower change of color value (ΔE = 12). In the case of HAD, the PEF application did not significantly influence its processing. In energy parameters, VMD and PEF+VMD reduced energy consumption and CO2 emissions.

Keywords: PEF technology, vacuum microwave drying, energy consumption, CO2 emissions

Procedia PDF Downloads 52
351 Optimal Tracking Control of a Hydroelectric Power Plant Incorporating Neural Forecasting for Uncertain Input Disturbances

Authors: Marlene Perez Villalpando, Kelly Joel Gurubel Tun

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In this paper, we propose an optimal control strategy for a hydroelectric power plant subject to input disturbances like meteorological phenomena. The engineering characteristics of the system are described by a nonlinear model. The random availability of renewable sources is predicted by a high-order neural network trained with an extended Kalman filter, whereas the power generation is regulated by the optimal control law. The main advantage of the system is the stabilization of the amount of power generated in the plant. A control supervisor maintains stability and availability in hydropower reservoirs water levels for power generation. The proposed approach demonstrated a good performance to stabilize the reservoir level and the power generation along their desired trajectories in the presence of disturbances.

Keywords: hydropower, high order neural network, Kalman filter, optimal control

Procedia PDF Downloads 269
350 Intensive Biological Control in Spanish Greenhouses: Problems of the Success

Authors: Carolina Sanchez, Juan R. Gallego, Manuel Gamez, Tomas Cabello

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Currently, biological control programs in greenhouse crops involve the use, at the same time, several natural enemies during the crop cycle. Also, large number of plant species grown in greenhouses, among them, the used cultivars are also wide. However, the cultivar effects on entomophagous species efficacy (predators and parasitoids) have been scarcely studied. A new method had been developed, using the factitious prey or host Ephestia kuehniella. It allows us to evaluate, under greenhouse or controlled conditions (semi-field), the cultivar effects on the entomophagous species effectiveness. The work was carried out in greenhouse tomato crop. It has been found the biological and ecological activities of predatory species (Nesidiocoris tenuis) and egg-parasitoid (Trichogramma achaeae) can be well represented with the use of the factitious prey or host; being better in the former than the latter. The data found in the trial are shown and discussed. The developed method could be applied to evaluate new plant materials before making available to farmers as commercial varieties, at low costs and easy use.

Keywords: cultivar effects, efficiency, predators, parasitoids

Procedia PDF Downloads 241
349 Neuronal Networks for the Study of the Effects of Cosmic Rays on Climate Variations

Authors: Jossitt Williams Vargas Cruz, Aura Jazmín Pérez Ríos

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The variations of solar dynamics have become a relevant topic of study due to the effects of climate changes generated on the earth. One of the most disconcerting aspects is the variability that the sun has on the climate is the role played by sunspots (extra-atmospheric variable) in the modulation of the Cosmic Rays CR (extra-atmospheric variable). CRs influence the earth's climate by affecting cloud formation (atmospheric variable), and solar cycle influence is associated with the presence of solar storms, and the magnetic activity is greater, resulting in less CR entering the earth's atmosphere. The different methods of climate prediction in Colombia do not take into account the extra-atmospheric variables. Therefore, correlations between atmospheric and extra-atmospheric variables were studied in order to implement a Python code based on neural networks to make the prediction of the extra-atmospheric variable with the highest correlation.

Keywords: correlations, cosmic rays, sun, sunspots and variations.

Procedia PDF Downloads 48
348 Inventory Management to Minimize Storage Costs and Improve Delivery Time in a Pharmaceutical Industry

Authors: Israel Becerril Rosales, Manuel González De La Rosa, Gerardo Villa Sánchez

Abstract:

In this work, the effects that produce not having a good inventory management is analyzed, in addition of the way that how it affects the storage costs. The research began conducting the historical analysis about stored products, its storage capacity, and distribution. The results were not optimal, since in all its raw materials (RM) have overstocking, the warehouse capacity is only used by 61%, does not have a specific place for each of its RM, causing that the delivery times increases and makes difficult a cyclical inventory. These shortcomings allowed to view and select as design alternatives the inventory ABC, so that depending on the consumption of each RM would be redistributed by using economic amount requested. Also, the Delphi method to ensure the practical applicability of the proposed tool was used, taking in account comments and suggestions of the involved experts, as well as the compliance of NOM-059-SSA1-2015 good manufacturing practices of drug. With the actions implemented, the utilization rate drops of 61% to 32% capacity, it shows that the warehouse was not designed properly due to there is not an industrial engineering area.

Keywords: lead time, improve delivery, storage costs, inventory management

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347 European Environmental Policy for Road Transport: Analysis of the Perverse Effects Generated and Proposals for a Good Practice Guide

Authors: Pedro Pablo Ramírez Sánchez, Alassane Ballé Ndiaye, Roberto Rendeiro Martín-Cejas

Abstract:

The aim of this paper is to analyse the different environmental policies adopted in Europe for car emissions, to comment on some of the possible perverse effects generated and point out these policies which are considered more efficient under the environmental perspective. This paper is focused on passenger cars as this category is the most significant in road transport. The utility of this research lies in this being the first step or basis to improve and optimise actual policies. The methodology applied in this paper refers to a comparative analysis from a practical and theoretical point of view of European environmental policies in road transport. This work describes an overview of the road transport industry in Europe pointing out some relevant aspects such as the contribution of road transport to total emissions and the vehicle fleet in Europe. Additionally, we propose a brief practice guide with the combined policies in order to optimise their aim.

Keywords: air quality, climate change, emission, environment, perverse effect, road transport, tax policy

Procedia PDF Downloads 132