Search results for: Monica Gonzalez Machorro

Authors: C. Castro-Egler, A. Durán-Escalante, A. García-González

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This paper presents a method to generate a finite element model of the human auditory inner ear system. The geometric model has been realized using 2D images from a virtual model of temporal bones. A point cloud has been gotten manually from those images to construct a whole mesh with hexahedral elements. The main difference with the predecessor models is the spiral shape of the cochlea with its three scales completely defined: scala tympani, scala media and scala vestibuli; which are separate by basilar membrane and Reissner membrane. To validate this model, numerical simulations have been realised with two models: an isolated inner ear and a whole model of human auditory system. Ideal conditions of displacement are applied over the oval window in the isolated Inner Ear model. The whole model is made up of the outer auditory channel, the tympani, the ossicular chain, and the inner ear. The boundary condition for the whole model is 1Pa over the auditory channel entrance. The numerical simulations by FEM have been done using a harmonic analysis with a frequency range between 100-10.000 Hz with an interval of 100Hz. The following results have been carried out: basilar membrane displacement; the scala media pressure according to the cochlea length and the transfer function of the middle ear normalized with the pressure in the tympanic membrane. The basilar membrane displacements and the pressure in the scala media make it possible to validate the response in frequency of the basilar membrane.

Keywords: finite elements method, human auditory system model, numerical analysis, 3D modelling cochlea

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Authors: Nora Gavira Duron, Cinthya Moreda Gonzalez-Ortega, Reyna Susana Garcia Ruiz

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This paper objective is to analyze the mathematics performance in the Learning Evaluation National Plan (PLANEA for its Spanish initials: Plan Nacional para la Evaluación de los Aprendizajes), applied to Mexican students who are enrolled in the last elementary-school year over the 2017-2018 academic year. Such test was conducted nationwide in 3,573 schools, using a sample of 108,083 students, whose average in mathematics, on a scale of 0 to 100, was 45.6 points. 75% of the sample analyzed did not reach the sufficiency level (60 points). It should be noted that only 2% got a 90 or higher score result. The performance is analyzed while considering whether there are differences in gender, marginalization level, public or private school enrollment, parents’ academic background, and living-with-parents situation. Likewise, this variable impact (among other variables) on school performance by gender is evaluated, considering multivariate logistic (Logit) regression analysis. The results show there are no significant differences in mathematics performance regarding gender in elementary school; nevertheless, the impact exerted by mothers who studied at least high school is of great relevance for students, particularly for girls. Other determining variables are students’ resilience, their parents’ economic status, and the fact they attend private schools, strengthened by the mother's education.

Keywords: multivariate regression analysis, academic performance, learning evaluation, mathematics result per gender

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Authors: Gyorgy Deak, Marius C. Raischi, Lucian P. Georgescu, Tiberius M. Danalache, Elena Holban, Madalina G. Boboc, Monica Matei, Catalina Iticescu, Marius V. Olteanu, Stefan Zamfir, Gabriel Cornateanu

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At present, on the Lower Danube, different types of pressures have been identified that affect the anadromous sturgeons stocks with an impact that leads to their decline. This paper presents techniques and procedures used by Romanian experts in the tagging and monitoring of anadromous sturgeons, as well as unique results at international level obtained on the basis of an informational volume collected in over 7 years of monitoring on these species behavior (both for adults as well as for ultrasonically tagged juveniles) on the Lower Danube. The local impact of hydrotechnical constructions (bottom sill, maritime navigation channel), the global impact of the poaching phenomenon and the impact of the restocking programs with sturgeon juveniles were assessed. Thus, the bottom sill impact on the Bala branch, the Bastroe Channel (cross-border impact) and the poaching phenomenon at the level of the Lower Danube was analyzed on the basis of a unique informational volume obtained through the use of patented monitoring systems by the Romanian experts (DKTB respectively, DKMR-01T). At the same time, the results from the monitoring of ultrasonically tagged sturgeon juveniles from the 2015 repopulation program are presented. Conclusions resulting from research can ensure favorable premises for finding some conservation solutions for CITES-protected sturgeon species that have survived for millions of years, currently being 1 species on the brink of extinction - Russian sturgeon, 2 species in danger of extinction - Beluga sturgeon and Stellate sturgeon and 2 species already extinct from the Lower Danube, namely common sturgeon and ship sturgeon.

Keywords: Lower Danube, sturgeons monitoring (adults and juveniles), tagging, impact on conservation

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Authors: Marianna Ciaccia, Gennaro Agrimi, Isabella Pisano, Maurizio Bettiga, Silvia Rapacioli, Giulia Mensa, Monica Marzagalli

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Objective: Untargeted metabolomic analysis of extracellular metabolites is a powerful approach that focuses on comprehensively profiling in the extracellular space. In this study, we applied extracellular metabolomic analysis to investigate the metabolism of two probiotic microorganisms with health benefits that extend far beyond the digestive tract and the immune system. Methods: Analytical techniques employed in extracellular metabolomic analysis encompass various technologies, including mass spectrometry (MS), which enables the identification of metabolites present in the fermentation media, as well as the comparison of metabolic profiles under different experimental conditions. Multivariate statistical analysis techniques like principal component analysis (PCA) or partial least squares-discriminant analysis (PLS-DA) play a crucial role in uncovering metabolic signatures and understanding the dynamics of metabolic networks. Results: Different types of supernatants from fermentation processes, such as dairy-free, not dairy-free media and media with no cells or pasteurized, were subjected to metabolite profiling, which contained a complex mixture of metabolites, including substrates, intermediates, and end-products. This profiling provided insights into the metabolic activity of the microorganisms. The integration of advanced software tools has facilitated the identification and characterization of metabolites in different fermentation conditions and microorganism strains. Conclusions: In conclusion, untargeted extracellular metabolomic analysis, combined with software tools, allowed the study of the metabolites consumed and produced during the fermentation processes of probiotic microorganisms. Ongoing advancements in data analysis methods will further enhance the application of extracellular metabolomic analysis in fermentation research, leading to improved bioproduction and the advancement of sustainable manufacturing processes.

Keywords: biotechnology, metabolomics, lactic bacteria, probiotics, postbiotics

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Authors: William Mahony, L. Jacqueline Hirth, Richard Rupp, Sandra Gonzalez, Roger Zoorob

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Background: The impact of the COVID-19 pandemic on physicians has been considered by many researchers, but less is known about non-physician healthcare workers. The aim of this study is to examine the association of COVID-19 safety training and communication with stress. Methods: A 91-item online survey was distributed, starting January 2, 2021, to non-physician healthcare workers, including physician assistants, nurse practitioners, and medical assistants (MAs) in the United States through email and social media. A $1 donation was made to the Red Cross for each completed survey. The survey consisted of demographics, occupational questions, and perceived stress (perceived stress scale, PSS). Items on the PSS were combined for an overall score and categorized according to the severity of perceived stress. Chi-square tests were performed for bivariate analyses of categorical variables. Results: Of the 284 participants consenting to complete the survey, 197 participants completed the full survey. MAs made up most of the sample at 79%. Among all respondents, 47% had moderate PSS scores (scored between 14 and 26), and 51% had severe PSS scores (scored between 27 and 40). Unvaccinated participants reported statistically significantly lower levels of perceived stress (p = 0.002). Performing tasks outside of typical job responsibilities was not associated with PSS scores (p = .667). Discussion: Non-physician healthcare workers demonstrated a high level of perceived stress overall. The association between vaccination status and perceived stress should be examined in order to evaluate whether vaccination levels could be improved with further education about the virus and associated risks.

Keywords: COVID-19, SARS-Cov-2, nursing, public health

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Authors: J. Gonzalez, P. Jimenez, C. Isaza

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Palms have different characteristics that make them vulnerable; that is the case of the Chamaedorea linearis, with the presence of solitary stems of small diameter and medium leaves, culturally harvested, and in religious festivities used. Additionally, they present a weak apical meristem as the only emergency point, slow development and growth, and an affectation due to the high rate of deforestation in Colombia. Propagation of this species can improve the pressure on wild populations and help their survival in the environment. In this study was used in 177 plants biosolids humus from the Wastewater Treatment Plant (WWTP), located at the UMNG Campus Cajica (Cundinamarca, Colombia). The experiment used a control and two treatments with 10% and 20% of humus. During the process, the variables evaluated were number of leaves, percentage of chlorophyll, stem length, and estimated leaf area. The data set were taking during 14 weeks before the reproductive maturity, evidencing that the most representative development of the palms was in the treatment of 20%, plants in this treatment presented major number of leaves, larger stems, a high quantity of chlorophyll, and was a first treatment that present pinnate leaves them represent an important point in maturity process. The research gives an opportunity to improve times of growth in another species of palms and plants (Product result from INV ING 2986 UMNG).

Keywords: biosolids, humus, growth, palms, wastewater treatment plant, WWTP

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Authors: Arredondo Valdés Roberto, Hernández Castillo Francisco Daniel, Laredo Alcalá Elan Iñaky, Gonzalez Gallegos Esmeralda, Castro Del Angel Epifanio

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The common bean or Phaseolus vulgaris L. is the most important food legume for direct consumption in the world. Fusarium dry rot in the major fungus disease affects Phaseolus vulgaris L, after planting. In another hand, Rhizoctonia can be found on all underground parts of the plant and various times during the growing season. In recent years, the world has conducted studies about the use of natural products as substitutes for herbicides and pesticides, because of possible ecological and economic benefits. Plants respond to fungal invasion by activating defense responses associated with accumulation of several enzymes and inhibitors, which prevent pathogen infection. This study focused on the role of proteins, peroxidase (POD), phenylalanine ammonia lyase (PAL), in imparting resistance to soft rot pathogens by applied different bacterial consortium, formulated and provided by Biofertilizantes de Méxicanos industries, analyzing the enzyme activity at different times of application (6 h, 12 h and 24 h). The resistance of these treatments was correlated with high POD and PAL enzyme activity as well as increased concentrations of proteins. These findings show that PAL, POD and synthesis of proteins play a role in imparting resistance to Phaseolus vulgaris L. soft rot infection by Fusarium and Rhizoctonia.

Keywords: fusarium, peroxidase, phenylalanine ammonia lyase, rhizoctonia

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Authors: Brenda O. Mazzola, Adriel Larsen, Romina P. Ollier, Leandro N. Ludueña, Vera A. Alvarez, Jimena S. Gonzalez

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Seaweed is a natural renewable resource with great potential that is not being used by the domestic industry. Here, it was used a kind of invasive algae U. Pinnatifida that causes serious ecological damage on the Argentinian coasts. Alginate is one of the most widely used materials for encapsulation, and has the advantage that is a natural polysaccharide derived from a marine plant. It can form thermally stable hydrogel in the presence of calcium cation. In addition, the hydrogel can be easily produced into particulate form by using simple and gentle method. The aim of this work was to obtain and to characterize novel compounds (alginate/seaweed powder) for the soil nutrition. Alginate water solutions were prepared by concentrations of 20, 30, 40 and 50 g/L, in those solutions 10g/L of seaweed powder was added. Then the dispersions were transferred from a beaker to the atomizer by a peristaltic pump (with 0.05 to 0.1 L/h flow). A tank was filled with 1 L of calcium chloride solution (4 g/L), and the solution was agitated with a magnetic stirrer. The beads were analyzed by means TGA, FTIR and swelling determinations. In addition, the improvements in the soil were qualitative measured. It was obtained beads with different diameters depend on the initial concentration and the flow used. A better dispersions of seaweed and optimal diameter for the plant nutrition applications were obtained for 40g/L concentration and 0.1 L/h flow. The beads show thermal stability and high swelling degree. It can be successfully obtained alginate beads with seaweed powder with a novelty application as plant nutrient.

Keywords: biodegradable, characterization, hydrogel, plant nutrition, seaweed

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Authors: S. Mohamed, D. Gonzalez, C. Sayada, P. Halfon

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Drug resistance mutations are routinely detected using standard Sanger sequencing, which does not detect minor variants with a frequency below 20%. The impact of detecting minor variants generated by ultra-deep sequencing (UDS) on HIV drug-resistance (DR) interpretations has not yet been studied. Fifty HIV-1 patients who experienced virological failure were included in this retrospective study. The HIV-1 UDS protocol allowed the detection and quantification of HIV-1 protease and reverse transcriptase variants related to genotypes A, B, C, E, F, and G. DeepChek®-HIV simplified DR interpretation software was used to compare Sanger sequencing and UDS. The total time required for the UDS protocol was found to be approximately three times longer than Sanger sequencing with equivalent reagent costs. UDS detected all of the mutations found by population sequencing and identified additional resistance variants in all patients. An analysis of DR revealed a total of 643 and 224 clinically relevant mutations by UDS and Sanger sequencing, respectively. Three resistance mutations with > 20% prevalence were detected solely by UDS: A98S (23%), E138A (21%) and V179I (25%). A significant difference in the DR interpretations for 19 antiretroviral drugs was observed between the UDS and Sanger sequencing methods. Y181C and T215Y were the most frequent mutations associated with interpretation differences. A combination of UDS and DeepChek® software for the interpretation of DR results would help clinicians provide suitable treatments. A cut-off of 1% allowed a better characterisation of the viral population by identifying additional resistance mutations and improving the DR interpretation.

Keywords: HIV-1, ultra-deep sequencing, Sanger sequencing, drug resistance

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Authors: Isabel Cristina Ortiz Trujillo, Lina Maria Martinez Sanchez, Felipe Hernández Restrepo, Daniel Gallego Gonzalez, Natalia Vargas Grisales, Camilo Andrés Agudelo Vélez

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Chorioamnionitis, is a pregnancy infection, causes different fetal and maternal symptoms. Streptococcus agalactiae present in the normal vaginal microflora of some women, favouring its abnormal multiplication during pregnancy, causing perinatal morbidity and mortality. Objective. Describe the clinical and epidemiological profile of the patients with diagnosis of clinical chorioanmionitis. Methodology. Descriptive, cross-sectional study. The population was patients with diagnosis of clinical chorioanmionitis. The information was taken from the medical records. The research was approved by the Ethics Committee. We used the program SPSS ® version 17.0 (SPSS Inc; Chicago, Illinois, USA) for the information analysis, descriptive statistics were used. Results. 78 patients in total with clinical chorioamnionitis, with a mean age of 26.3 ±5, 8 years old, the 69.2% primigravid women. 2.6% of women had positive culture for Streptococcus agalactiae in urine sample during current pregnancy and 30.7% had received some kind of antibiotics during current pregnancy. The 57.7% had 37 to 40 weeks of gestation in the current pregnancy it was calculated more frequently by ultrasound (66.7% in first quarter, 11.5% in the second and 1.9% in the third). In a 60.3% way of termination of pregnancy was vaginal and a 35.9 percent were caesarean section. Among the women in the study, a 30.8% had premature rupture of membranes. Conclusion. The chorioamnionitis continues to be an important cause of antibiotic use during pregnancy or labour and the decision to do a caesarean, with highest percentage in pregnancies-preterm and preterm premature rupture of membranes.

Keywords: chorioamnionitis, Streptococcus agalactiae, pregnancy complications, infectious

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Authors: Maria Monica D. Espinosa

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This study aimed to identify and examine the characteristics of an effective leader in a Hospital institution from the perspectives of military nurse-managers. The researcher extracted the different facets of leadership from the stories of six nurse- managers from a military hospital. The stories which are in pre-reflective stage convey an unbiased perspective from which clinical leadership may be defined. Using Phenomenology as a method of Research, the lived experiences of the military nurse-managers served as empirical data which were reflected upon until the formulation of insights. The information from the co-researchers became gallows from which the characteristics of effective leadership in the clinical area were drawn. These insights were synthesized through layers of reflection that resulted to the knowledge about clinical leadership. The reflections are the following, (a) Clinical leaders develop their skills through experiences and hardwork; (b) Clinical leaders are devoted; (c) Clinical leaders are focused; (d) Clinical leaders are good in interpersonal relationship; (e) Clinical leaders are mentors; (f) Clinical leaders seek affirmation and recognition; and (g) Clinical leaders are responsible and dependable. The common themes that emerged from the nurse manager’s stories showed that clinical leadership maybe attained if leaders possessed the following traits, (a) The gift to establish a steadfast and firm management; (b) The proficiency to guide and encourage others towards the achievement of their goals and objectives; (c) The ability to instigate participative and collaborative work among his/her subordinates and (d) The aptitude and skill to address the institutional concerns in their unit. In the future, Clinical leaders should continually adapt an evaluation program on how they can relate socially with their subordinates, the result of which can be used as a basis in developing strategies on relationship enhancement. Moreover, they should empower the nurses by allowing them to voice out their opinions and concerns regarding assignments, role expectations, and workload issues to improve and strengthen the relationships among nurses. Lastly, they can incorporate a collaborative strategy to promote professional socialization attitudes of nurse managers who work with staff nurses to improve the quality of their proficiencies and enhance a positive clinical environment.

Keywords: clinical leadership, experiences, implications, military nurse - managers, phenomenology

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Authors: María Jesús Luengo-Valderrey, Mónica Moso-Díez

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In the knowledge-based economy, innovation is considered essential in order to achieve survival and growth in organizations. On the other hand, knowledge management is currently understood as one of the keys to innovation process. Both factors are generally admitted as generators of competitive advantage in organizations. Specifically, activities on R&D&I and those that generate internal knowledge have a positive influence in innovation results. This paper examines this effect and if it is similar or not is what we aimed to quantify in this paper. We focus on the impact that proportion of knowledge workers, the R&D&I investment, the amounts destined for ICTs and training for innovation have on the variation of tangible and intangibles returns for the sector of high and medium technology in Spain. To do this, we have performed an empirical analysis on the results of questionnaires about innovation in enterprises in Spain, collected by the National Statistics Institute. First, using clusters methodology, the behavior of these enterprises regarding knowledge management is identified. Then, using SEM methodology, we performed, for each cluster, the study about cause-effect relationships among constructs defined through variables, setting its type and quantification. The cluster analysis results in four groups in which cluster number 1 and 3 presents the best performance in innovation with differentiating nuances among them, while clusters 2 and 4 obtained divergent results to a similar innovative effort. However, the results of SEM analysis for each cluster show that, in all cases, knowledge workers are those that affect innovation performance most, regardless of the level of investment, and that there is a strong correlation between knowledge workers and investment in knowledge generation. The main findings reached is that Spanish high and medium technology companies improve their innovation performance investing in internal knowledge generation measures, specially, in terms of R&D activities, and underinvest in external ones. This, and the strong correlation between knowledge workers and the set of activities that promote the knowledge generation, should be taken into account by managers of companies, when making decisions about their investments for innovation, since they are key for improving their opportunities in the global market.

Keywords: high and medium technology sector, innovation, knowledge management, Spanish companies

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Authors: Gizem Derya Demir, Ilayda Yankilic, Daglar Karamuftuoglu, Dante Dorantes

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ABSTRACT HAPTIC ROBOTIC GLOVE FOR TELE-EXPLORATION OF EXPLOSIVE DEVICES Gizem Derya Demir, İlayda Yankılıç, Dağlar Karamüftüoğlu, Dante J. Dorantes-González Department of Mechanical Engineering, MEF University Ayazağa Cad. No.4, 34396 Maslak, Sarıyer, İstanbul, Turkey Nowadays, terror attacks are, unfortunately, a more common threat around the world. Therefore, safety measures have become much more essential. An alternative to providing safety and saving human lives is done by robots, such as disassembling and liquidation of bombs. In this article, remote exploration and manipulation of potential explosive devices from a safe-distance are addressed by designing a novel, simple and ergonomic haptic robotic glove. SolidWorks® Computer-Aided Design, computerized dynamic simulation, and MATLAB® kinematic and static analysis were used for the haptic robotic glove and finger design. Angle controls of servo motors were made using ARDUINO® IDE codes on a Makeblock® MegaPi control card. Simple grasping dexterity solutions for the fingers were obtained using one linear soft and one angle sensors for each finger, and six servo motors are used in total to remotely control a slave multi-tooled robotic hand. This project is still undergoing and presents current results. Future research steps are also presented.

Keywords: Dexterity, Exoskeleton, Haptics , Position Control, Robotic Hand , Teleoperation

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Authors: Mario Isaza-Ruget, Claudia C. Colmenares-Mejia, Nancy Yomayusa, Camilo A. González, Andres Cely, Jossie Murcia

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Quantification of risks associated with complications development from chronic kidney disease (CKD) through accurate survival models can help with patient management. A retrospective cohort that included patients diagnosed with CKD from a primary care program and followed up between 2013 and 2018 was carried out. Time-dependent and static covariates associated with demographic, clinical, and laboratory factors were included. Deep Learning (DL) survival analyzes were developed for three CKD outcomes: CKD stage progression, >25% decrease in Estimated Glomerular Filtration Rate (eGFR), and Renal Replacement Therapy (RRT). Models were evaluated and compared with Random Survival Forest (RSF) based on concordance index (C-index) metric. 2.143 patients were included. Two models were developed for each outcome, Deep Neural Network (DNN) model reported C-index=0.9867 for CKD stage progression; C-index=0.9905 for reduction in eGFR; C-index=0.9867 for RRT. Regarding the RSF model, C-index=0.6650 was reached for CKD stage progression; decreased eGFR C-index=0.6759; RRT C-index=0.8926. DNN models applied in survival analysis context with considerations of longitudinal covariates at the start of follow-up can predict renal stage progression, a significant decrease in eGFR and RRT. The success of these survival models lies in the appropriate definition of survival times and the analysis of covariates, especially those that vary over time.

Keywords: artificial intelligence, chronic kidney disease, deep neural networks, survival analysis

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Authors: Camila Amin-Puello, Lina Vasco-Diaz, Juan Ramirez-Arias, Claudia Munoz, Carlos Gonzalez-Calderon

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Operational flexibility is a fundamental aspect in the field of airlines because although demand is constantly changing, it is the duty of companies to provide a service to users that satisfies their needs in an efficient manner without sacrificing factors such as comfort, safety and other perception variables. The objective of this research is to understand the factors that describe and explain operational flexibility by implementing advanced analytical methods such as exploratory factor analysis and structural equation modeling, examining multiple levels of operational flexibility and understanding how these variable influences users' decision-making when choosing an airline and in turn how it affects the airlines themselves. The use of a hybrid model and latent variables improves the efficiency and accuracy of airline performance prediction in the unpredictable Colombian market. This pioneering study delves into traveler motivations and their impact on domestic flight demand, offering valuable insights to optimize resources and improve the overall traveler experience. Applying the methods, it was identified that low-cost airlines are not useful for flexibility, while users, especially women, found airlines with greater flexibility in terms of ticket costs and flight schedules to be more useful. All of this allows airlines to anticipate and adapt to their customers' needs efficiently: to plan flight capacity appropriately, adjust pricing strategies and improve the overall passenger experience.

Keywords: hybrid choice model, airline, business travelers, domestic flights

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Authors: Adriana Martínez-Arias, John Josephraj Selvaraj, Luis Octavio González-Salcedo

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In the Colombian Pacific, Dorado fish (Coryphaena hippurus L.) fisheries is of great commercial interest. However, its habitat and fisheries may be affected by climatic change especially by the actual increase in sea surface temperature. Hence, it is of interest to study the dynamics of these species fishing zones. In this study, we developed Artificial Neural Networks (ANN) models to predict Catch per Unit Effort (CPUE) as an indicator of species abundance. The model was based on four oceanographic variables (Chlorophyll a, Sea Surface Temperature, Sea Level Anomaly and Bathymetry) derived from satellite data. CPUE datasets for model training and cross-validation were obtained from logbooks of commercial fishing vessel. Sea surface Temperature for Colombian Pacific were projected under Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5 using Coupled Model Intercomparison Project Phase 5 (CMIP5) and CPUE maps were created. Our results indicated that an increase in sea surface temperature reduces the potential fishing zones of this species in the Colombian Pacific. We conclude that ANN is a reliable tool for simulation of climate change effects on the potential fishing zones. This research opens a future agenda for other species that have been affected by climate change.

Keywords: climatic change, artificial neural networks, dorado fish, CPUE

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Authors: Guang Zou, Kian Banisoleiman, Arturo González

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Crack initiation and propagation threatens structural integrity of welded joints and normally inspections are assigned based on crack propagation models. However, the approach based on crack propagation models may not be applicable for some high-quality welded joints, because the initial flaws in them may be so small that it may take long time for the flaws to develop into a detectable size. This raises a concern regarding the inspection planning of high-quality welded joins, as there is no generally acceptable approach for modeling the whole fatigue process that includes the crack initiation period. In order to address the issue, this paper reviews treatment methods for crack initiation period and initial crack size in crack propagation models applied to inspection planning. Generally, there are four approaches, by: 1) Neglecting the crack initiation period and fitting a probabilistic distribution for initial crack size based on statistical data; 2) Extrapolating the crack propagation stage to a very small fictitious initial crack size, so that the whole fatigue process can be modeled by crack propagation models; 3) Assuming a fixed detectable initial crack size and fitting a probabilistic distribution for crack initiation time based on specimen tests; and, 4) Modeling the crack initiation and propagation stage separately using small crack growth theories and Paris law or similar models. The conclusion is that in view of trade-off between accuracy and computation efforts, calibration of a small fictitious initial crack size to S-N curves is the most efficient approach.

Keywords: crack initiation, fatigue reliability, inspection planning, welded joints

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Authors: Bello Gonzalez, Setten Van M., Brouwer M.

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The chicken small intestine represents a dynamic and complex organ in which the enzymatic digestion and absorption of nutrients take place. The development of an in vitro fermentation chicken small intestinal model could be used as an alternative to explore the interaction between the microbiota and nutrient metabolism and to enhance the efficacy of targeting interventions to improve animal health. In the present study we have developed an in vitro fermentation chicken ileum microbiota model for unrevealing the complex interaction of ileum microbial community under physiological conditions. A two-vessel continuous fermentation process simulating in real-time the physiological conditions of the ileum content (pH, temperature, microaerophilic/anoxic conditions, and peristaltic movements) has been standardized as a proof of concept. As inoculum, we use a pool of ileum microbial community obtained from chicken broilers at the age of day 14. The development and validation of the model provide insight into the initial characterization of the ileum microbial community and its dynamics over time-related to nutrient assimilation and fermentation. Samples can be collected at different time points and can be used to determine the microbial compositional structure, dynamics, and diversity over time. The results of studies using this in vitro model will serve as the foundation for the development of a whole small intestine in vitro fermentation chicken gastrointestinal model to complement our already established in vitro fermentation chicken caeca model. The insight gained from this model could provide us with some information about the nutritional strategies to restore and maintain chicken gut homeostasis. Moreover, the in vitro fermentation model will also allow us to study relationships between gut microbiota composition and its dynamics over time associated with nutrients, antimicrobial compounds, and disease modelling.

Keywords: broilers, in vitro model, ileum microbiota, fermentation

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Authors: Maria Gonzalez Alriols, Itziar Egues, Maria A. Andres, Mirari Antxustegi

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Peer to peer learning is an educational tool very useful to enhance teamwork and reinforce cooperation between mates. It is particularly successful to work with students of different level of previous knowledge, as it often happens among pupils of subjects in the first course of science and engineering studies. Depending on the performed pre-university academic itinerary, the acquired knowledge in disciplines as mathematics, physics, or chemistry may be quite different. This fact is an added difficulty to the tuition of first-course basic science subjects of engineering degrees, with inexperienced students that do not know each other. In this context, peer to peer learning applied in small groups facilitates the communication between mates and makes it easier for the students with low level to be helped by the ones with better prior knowledge. In this work, several collaborative learning strategies were designed to be applied in the tuition of the subject 'chemistry', which is imparted in the first course of an engineering degree. Students were organized in groups combining mates with different level of prior knowledge. The teaching role was offered to the more experienced students who were responsible for designing learning pills to help the other mates in their group. This workload was rewarded with an extra mark, and more extra points were offered to all the group mates if every student in the group reached a determined level at the end of the semester. It was very important to start these activities from the beginning of the semester in order to avoid absenteeism. The obtained results were positive as a higher percentage of mates signed up and passed the final exam, the obtained final marks were higher, and a much better atmosphere was observed in the class.

Keywords: peer to peer tuition, collaborative learning, engineering instruction, chemistry

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Authors: Thalía Moreno-García Malo, Santiago Torres-Ríos, María G. González-Cruz, María M. Hernández-Arroyo, Sergio R. Trejo-Estrada

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Agave atrovirens is the main source of agave sap, the raw material for the production of pulque, an artisanal fermented beverage, traditional since prehispanic times in the highlands of central Mexico. Agave sap is rich in glucose, sucrose and fructooligosaccharides, and strongly differs from agave syrup from A. tequilana, which is mostly a high molecular weight fructan. Agave sap is converted into pulque by a highly diverse microbial community which includes bacteria, yeast and even filamentous fungi. The bacterial diversity has been recently studied. But the composition of consortia derived from directed enrichments differs sharply from the whole fermentative consortium. Using classical microbiology methods, and selective liquid and solid media formulations, either bacterial or fungal consortia were developed and analyzed. Bacterial consortia able to catabolize specific prebiotic saccharides were selected and preserved for future developments. Different media formulations, selective for bacterial genera such as Bifidobacterium, Lactobacillus, Pediococcus, Lactococcus and Enterococcus were also used. For yeast, specific media, osmotic pressure and unique carbon sources were used as selective agents. Results show that most groups are represented in the enrichment cultures; although very few are recoverable from the whole consortium in artisanal pulque. Diversity and abundance vary among consortia. Potential bacterial probiotics obtained from agave sap and agave juices show tolerance to hydrochloric acid, as well as strong antimicrobial activity.

Keywords: Agave, pulque, microbial consortia, prebiotic activity

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Authors: Felipe Bedoya Maya, Agustina Calatayud, Vileydy Gonzalez Mejia

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Encompassing inventory, warehousing, and transportation management, logistics is a crucial predictor of firm performance. This has been extensively proven by extant literature in business and operations management. Logistics is also a fundamental determinant of a country's ability to access international markets. Available studies in international and transport economics have shown that limited transport infrastructure and underperforming transport services can severely affect international competitiveness. However, the evidence lacks the overall impact of logistics performance-encompassing all inventory, warehousing, and transport components- on global trade. In order to fill this knowledge gap, the paper uses a gravitational trade model with 155 countries from all geographical regions between 2007 and 2018. Data on logistics performance is obtained from the World Bank's Logistics Performance Index (LPI). First, the relationship between logistics performance and a country’s total trade is estimated, followed by a breakdown by the economic sector. Then, the analysis is disaggregated according to the level of technological intensity of traded goods. Finally, after evaluating the intensive margin of trade, the relevance of logistics infrastructure and services for the extensive trade margin is assessed. Results suggest that: (i) improvements in both logistics infrastructure and services are associated with export growth; (ii) manufactured goods can significantly benefit from these improvements, especially when both exporting and importing countries increase their logistics performance; (iii) the quality of logistics infrastructure and services becomes more important as traded goods are technology-intensive; and (iv) improving the exporting country's logistics performance is essential in the intensive margin of trade while enhancing the importing country's logistics performance is more relevant in the extensive margin.

Keywords: gravity models, infrastructure, international trade, logistics

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Authors: Oloruntegbe Kunle Oke, Alake Ese Monica, Odutuyi Olubu Musili

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This research explores the differing effectiveness of cascade and cluster models in professional development programs for educators in Ondo State, Nigeria. The cascade model emphasizes a top-down approach, where training is cascaded from expert trainers to lower levels of teachers. In contrast, the cluster model, a bottom-up approach, fosters collaborative learning among teachers within specific clusters. Through a review of the literature and empirical studies of the implementations of the former in two academic sessions followed by the cluster model in another two, the study examined their effectiveness on teacher development, productivity and students’ achievements. The study also drew a comparative analysis of the strengths and weaknesses associated with each model, considering factors such as scalability, cost-effectiveness, adaptability in various contexts, and sustainability. 2500 teachers from Ondo State Primary Schools participated in the cascade with intensive training in five zones for a week each in two academic sessions. On the other hand, 1,980 and 1,663 teachers in 52 and 34 clusters, respectively, were in the first and the following session. The programs were designed for one week of rigorous training of teachers by facilitators in the former while the latter was made up of four components: sit-in-observation, need-based assessment workshop, pre-cluster and the actual cluster meetings in addition to sensitization, and took place one day a week for ten weeks. Validated Cluster Impact Survey Instruments, CISI and Teacher’s Assessment Questionnaire (TAQ) were administered to ascertain the effectiveness of the models during and after implementation. The findings from the literature detailed specific effectiveness, strengths and limitations of each approach, especially the potential for inconsistencies and resistance to change. Findings from the data collected revealed the superiority of the cluster model. Response to TAQ equally showed content knowledge and skill update in both but were more sustained in the cluster model. Overall, the study contributes to the ongoing discourse on effective strategies for improving teacher training and enhancing student outcomes, offering practical recommendations for the development and implementation of future professional development projects.

Keywords: cascade model, cluster model, teachers’ development, productivity, students’ achievement

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Authors: Saeid Mehvari, Yolanda Sanchez-Vicente, Sergio González Sánchez, Khalid Lafdi

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Abstract- Materials with a combination of transparency, electrical conductivity, and flexibility are required in the ‎growing electronic sector. In this research, electrically conductive and flexible films have been prepared. These ‎composite films consist of dispersing micro-copper particles into polyurethane (PU) matrix. Two sets of samples were ‎made using both spin coating technique (sample thickness lower than 30 μm) and materials casting (sample thickness ‎lower than 100 μm). Copper concentrations in the PU matrix varied from 0.5 to 20% by volume. The dispersion of ‎micro-copper particles into polyurethane (PU) matrix were characterised using optical microscope and scanning electron ‎microscope. The electrical conductivity measurement was carried out using home-made multimeter set up under ‎pressures from 1 to 20 kPa through thickness and in plane direction. It seems that samples made by casting were not ‎conductive. However, the sample made by spin coating shows through-thickness conductivity when they are under ‎pressure. The results showed that spin-coated films with higher concentration of 2 vol. % of copper displayed a ‎significant increase in the conductivity value, known as percolation threshold. The maximum conductivity of 7.2 × 10-1 ‎S∙m-1 was reached at concentrations of filler with 20 vol. % at 20kPa. A semi-empirical model with adjustable ‎coefficients was used to fit and predict the electrical behaviour of composites. For the first time, the finite element ‎method based on the representative volume element (FE-RVE) was successfully used to predict their electrical ‎behaviour under applied pressures. ‎

Keywords: electrical conductivity, micro copper, numerical simulation, percolation threshold, polyurethane, RVE model

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Authors: P. Gil Del Álamo, J. García Pereda, A. Castañeda De La Paz, D. Arazola Lopez, M. D. Cubiles De La Vega, A. Enguíx González, J. M. Muñoz Pichardo

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In the last decades, obesity has more than doubled and is, with overweight, the second leading cause of preventable death. Despite multiple strategies against obesity, no country to date has reduced the number of obese people. To achieve World Health Organization’s target to reverse this tendency we need dramatic and different actions to engage the civil society in creating demand for a healthy style of life. The objective of this study is to demonstrate that a social media as the television can be used to convince the civil society that a healthy nutrition and physical activity are affordable, effective and necessary to prevent and to treat the obesity. Methodology: 61 individuals (34 women and 27 men) with obesity (mean BMI 45,51) were recruited to follow during 22 weeks an intensive lifestyle intervention in order to lose weight in a healthy manner. They were not isolated or moved from their usual environment. This program included endocrinological and nutritional assessment, promotion of physical activity and psychological support. BMI was measured every week. Time to leave obesity between men and women was analyzed with a survival analysis. Results: BMI decreased in all the cases. Analysing Time to leave obesity, around the week 30, 25% of men leave the obesity and around the week 39, 25% of women leave the obesity too. Conclusion: We demonstrate the audience that improving the quality of the diet and increasing the physical activity is a realistic way to lose weight. This evidence can encourage the people to act in their own self-interest changing their style of life in order to prevent or to reduce their overweight.

Keywords: obesity epidemic, obesity prevention, obesity strategies, social media

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Authors: Paula García-Llamas, Polonia Díez González, Angela Taboada

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In an era marked by unprecedented anthropogenic alterations to landscapes and biodiversity, the consequential loss of fauna, flora, and habitats poses a grave concern. It is imperative to evaluate our capacity to manage and mitigate such changes effectively. This study aims to scrutinize the efficacy of the Natura 2000 Network (NN2000) in landscape conservation within the autonomous community of Castile and Leon (Spain), spanning from 1990 to 2018. Leveraging land use change maps from the European Corine Land Cover database across four subperiods (1990-2000, 2000-2006, 2006-2012, and 2012-2018), we quantified alterations occurring both within NN2000 protected sites and within a 5km buffer zone. Additionally, we spatially assess land use/land cover patterns of change considering fluxes of various habitat types defined within NN2000. Our findings reveal that the protected areas under NN2000 were particularly susceptible to change, with the most significant transformations observed during the 1990-2000 period. Predominant change processes include secondary succession and scrubland formation due to land use cessation, deforestation, and agricultural intensification. While NN2000 demonstrates efficacy in curtailing urbanization and industrialization within buffer zones, its management measures have proven insufficient in safeguarding landscapes against the dynamic changes witnessed between 1990 and 2018, especially in relation to rural abandonment.

Keywords: Corine land cover, land cover changes, site of community importance, special protection area

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Authors: Jorge Gonzalez-Camus

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In this work is proved the existence of at least one minimal and maximal mild solutions to the Cauchy problem, for fractional evolution equation of neutral type, involving a general kernel. An operator A generating a resolvent family and integral resolvent family on a Banach space X and a kernel belonging to a large class appears in the equation, which covers many relevant cases from physics applications, in particular, the important case of time - fractional evolution equations of neutral type. The main tool used in this work was the Kuratowski measure of noncompactness and fixed point theorems, specifically Darbo-type, and an iterative method of lower and upper solutions, based in an order in X induced by a normal cone P. Initially, the equation is a Cauchy problem, involving a fractional derivate in Caputo sense. Then, is formulated the equivalent integral version, and defining a convenient functional, using the theory of resolvent families, and verifying the hypothesis of the fixed point theorem of Darbo type, give us the existence of mild solution for the initial problem. Furthermore, the existence of minimal and maximal mild solutions was proved through in an iterative method of lower and upper solutions, using the Azcoli-Arzela Theorem, and the Gronwall’s inequality. Finally, we recovered the case derivate in Caputo sense.

Keywords: fractional evolution equations, Volterra integral equations, minimal and maximal mild solutions, neutral type equations, non-local in time equations

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Authors: Ana Munguia, Gerardo Ortiz, Guadalupe Gonzalez, Fiacro Jimenez

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Parkinson's disease (PD) is a neurodegenerative disorder that causes motor and cognitive symptoms. The first-choice treatment for these patients is pharmacological, but this generates several side effects. Because of that new treatments were introduced such as Repetitive Transcranial Magnetic Stimulation (rTMS) in order to improve the life quality of the patients. Several studies suggest significant changes in motor symptoms. However, there is a great diversity in the number of pulses, amplitude, frequency and stimulation targets, which results in inconsistent data. In addition, these studies do not have an analysis of the neuropsychological effects of the treatment. The main purpose of this study is to evaluate the impact of rTMS on the cognitive performance of 6 patients with H&Y III and IV (45-65 years, 3 men and 3 women). An initial neuropsychological and neurological evaluation was performed. Patients were randomized into two groups; in the first phase one received rTMS in the supplementary motor area, the other group in the dorsolateral prefrontal cortex contralateral to the most affected hemibody. In the second phase, each group received the stimulation in the area that he had not been stimulated previously. Reassessments were carried out at the beginning, at the end of each phase and a follow-up was carried out 6 months after the conclusion of the stimulation. In these preliminary results, it is reported that there's no statistically significant difference before and after receiving rTMS in the neuropsychological test scores of the patients, which suggests that the cognitive performance of patients is not detrimental. There are even tendencies towards an improvement in executive functioning after the treatment. What added to motor improvement, showed positive effects in the activities of the patients' daily life. In a later and more detailed analysis, will be evaluated the effects in each of the patients separately in relation to the functionality of the patients in their daily lives.

Keywords: Parkinson's disease, rTMS, cognitive, treatment

Procedia PDF Downloads 145

Authors: Amanda C. Q. M. Vieira, Cybelly M. Melo, Camila B. M. Figueirêdo, Giovanna C. R. M. Schver, Salvana P. M. Costa, Magaly A. M. de Lyra, Ping I. Lee, José L. Soares-Sobrinho, Pedro J. Rolim-Neto, Mônica F. R. Soares

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Epiisopiloturine (EPI) is a drug candidate that is extracted from Pilocarpus microphyllus and isolated from the waste of Pilocarpine. EPI has demonstrated promising schistosomicidal, leishmanicide, anti-inflammatory and antinociceptive activities, according to in vitro studies that have been carried out since 2009. However, this molecule shows poor aqueous solubility, which represents a problem for the release of the drug candidate and its absorption by the organism. The purpose of the present study is to investigate the extent of enhancement of kinetic solubility of a solid solution (SS) of EPI in hipromellose phthalate HP-55 (HPMCP), an enteric polymer carrier. SS was obtained by the solvent evaporation methodology, using acetone/methanol (60:40) as solvent system. Both EPI and polymer (drug loading 10%) were dissolved in this solvent until a clear solution was obtained, and then dried in oven at 60ºC during 12 hours, followed by drying in a vacuum oven for 4 h. The results show a considerable modification in the crystalline structure of the drug candidate. For instance, X-ray diffraction (XRD) shows a crystalline behavior for the EPI, which becomes amorphous for the SS. Polarized light microscopy, a more sensitive technique than XRD, also shows completely absence of crystals in SS sample. Differential Scanning Calorimetric (DSC) curves show no signal of EPI melting point in SS curve, indicating, once more, no presence of crystal in this system. Interaction between the drug candidate and the polymer were found in Infrared microscopy, which shows a carbonyl 43.3 cm-1 band shift, indicating a moderate-strong interaction between them, probably one of the reasons to the SS formation. Under sink conditions (pH 6.8), EPI SS had its dissolution performance increased in 2.8 times when compared with the isolated drug candidate. EPI SS sample provided a release of more than 95% of the drug candidate in 15 min, whereas only 45% of EPI (alone) could be dissolved in 15 min and 70% in 90 min. Thus, HPMCP demonstrates to have a good potential to enhance the kinetic solubility profile of EPI. Future studies to evaluate the stability of SS are required to conclude the benefits of this system.

Keywords: epiisopiloturine, hipromellose phthalate HP-55, pharmaceuticaltechnology, solubility

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Authors: Anny Zambrano, German Gonzalez, Yair Quintero

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The continuum damage concept is used to study the interaction between hydraulic fractures and natural fractures, the objective is representing the path and relation among this two fractures types and predict its complex behavior without the need to pre-define their direction as occurs in other finite element applications, providing results more consistent with the physical behavior of the phenomenon. The approach uses finite element simulations through Abaqus software to model damage fracturing, the fracturing process by damage propagation in a rock. The modeling the phenomenon develops in two dimensional (2D) so that the fracture will be represented by a line and the crack front by a point. It considers nonlinear constitutive behavior, finite strain, time-dependent deformation, complex boundary conditions, strain hardening and softening, and strain based damage evolution in compression and tension. The complete governing equations are provided and the method is described in detail to permit readers to replicate all results. The model is compared to models that are published and available. Comparisons are focused in five interactions between natural fractures (NF) and hydraulic fractures: Fractured arrested at NF, crossing NF with or without offset, branching at intersecting NFs, branching at end of NF and NF dilation due to shear slippage. The most significant new finding is, that is not necessary to use pre-defined addresses propagation and stress condition can be evaluated as a dominant factor in the process. This is important because it can model in a more real way the generated complex hydraulic fractures, and be a valuable tool to predict potential problems and different geometries of the fracture network in the process of fracturing due to fluid injection.

Keywords: continuum damage, hydraulic fractures, natural fractures, complex fracture network, stiffness

Procedia PDF Downloads 343

Authors: González A. Julio, Ramírez L. Leonardo, Puerta A. Gabriel

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Telemedicine services use a large amount of data, most of which are diagnostic images in Digital Imaging and Communications in Medicine (DICOM) and Health Level Seven (HL7) formats. Metadata is generated from each related image to support their identification. This study presents the use of decision trees for the optimization of information search processes for diagnostic images, hosted on the cloud server. To analyze the performance in the server, the following quality of service (QoS) metrics are evaluated: delay, bandwidth, jitter, latency and throughput in five test scenarios for a total of 26 experiments during the loading and downloading of DICOM images, hosted by the telemedicine group server of the Universidad Militar Nueva Granada, Bogotá, Colombia. By applying decision trees as a data mining technique and comparing it with the sequential search, it was possible to evaluate the search times of diagnostic images in the server. The results show that by using the metadata in decision trees, the search times are substantially improved, the computational resources are optimized and the request management of the telemedicine image service is improved. Based on the experiments carried out, search efficiency increased by 45% in relation to the sequential search, given that, when downloading a diagnostic image, false positives are avoided in management and acquisition processes of said information. It is concluded that, for the diagnostic images services in telemedicine, the technique of decision trees guarantees the accessibility and robustness in the acquisition and manipulation of medical images, in improvement of the diagnoses and medical procedures in patients.

Keywords: cloud storage, decision trees, diagnostic image, search, telemedicine

Procedia PDF Downloads 204