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Ítem Modified Slash Lindley Distribution(Hindawi, 2017) Reyes, Jimmy; Venegas, Osvaldo; Gómez, Héctor W.Ítem The Power Muth Distribution*(Taylor&Francis and VGTU, 2017) Jodrá, Pedro; Gómez, Héctor Wladimir; Jiménez-Gamero, María Dolores; Alba-Fernández, María VirtudesMuth introduced a probability distribution with application in reliability theory. We propose a new model from the Muth law. This paper studies its statistical properties, such as the computation of the moments, computer generation of pseudo-random data and the behavior of the failure rate function, among others. The estimation of parameters is carried out by the method of maximum likelihood and a Monte Carlo simulation study assesses the performance of this method. The practical usefulness of the new model is illustrated by means of two real data sets, showing that it may provide a better fit than other probability distributionsÍtem Melatonin relations with respiratory Quotient Weaken on acute exposure to high altitude(Frontiers Media SA, 2018) Tapia, Marcelo; Wulff-Zottele, Cristian; De Gregorio, Nicole; Lang, Moring; Varela, Héctor; Serón-Ferré, María Josefa; Vivaldi, Ennio A; Araneda, Oscar F.; Silva-Urra, Juan; Gunga, Hanss-Christian; Behn, ClausHigh altitude (HA) exposure may affect human health and performance by involving the body timing system. Daily variations of melatonin may disrupt by HA exposure, thereby possibly affecting its relations with a metabolic parameter like the respiratory quotient (RQ). Sea level (SL) volunteers (7 women and 7 men, 21.0 ± 2.04 y) were examined for daily changes in salivary melatonin concentration (SMC). Sampling was successively done at SL (Antofagasta, Chile) and, on acute HA exposure, at nearby Caspana (3,270 masl). Saliva was collected in special vials (Salimetrics Oral Swab, United Kingdom) at sunny noon (SMCD) and in the absence of blue light at midnight (SMCN). The samples were obtained after rinsing the mouth with tap water and were analyzed for SMC by immunoassay (ELISA kit; IBL International, Germany). RQ measurements (n = 12) were realized with a portable breath to breath metabolic system (OxiconTM Mobile, Germany), between 8:00 PM and 10:00 PM, once at either location. At SL, SMCD, and SMCN values (mean ± SD) were, respectively, 2.14 ± 1.30 and 11.6 ± 13.9 pg/ml (p < 0.05). Corresponding values at HA were 8.83 ± 12.6 and 13.7 ± 16.7 pg/ml (n.s.). RQ was 0.78 ± 0.07 and 0.89 ± 0.08, respectively, at SL and HA (p < 0.05). Differences between SMCN and SMCD (SMCN–SMCD) strongly correlate with the corresponding RQ values at SL (r = −0.74) and less tight at HA (r = −0.37). Similarly, mean daily SMC values (SMC¯ x) tightly correlate with RQ at SL (r = −0.79) and weaker at HA (r = −0.31). SMCN–SMCD, as well as, SMC¯ x values at SL, on the other hand, respectively, correlate with the corresponding values at HA (r = 0.71 and r = 0.85). Acute exposure to HA appears to loosen relations of SMC with RQ. A personal profile in daily SMC variation, on the other hand, tends to be conserved at HA.Ítem Truncated power-normal distribution with application to non-negative measurements(MDPI, 2018) Castillo, Nabor O.; Gallardo, Diego I.; Bolfarine, Heleno; Gómez, Héctor W.This paper focuses on studying a truncated positive version of the power-normal (PN) modelconsidered in Durrans (1992). The truncation point is considered to be zero so that the resulting model is an extension of the half normal distribution. Some probabilistic properties are studied for the proposed model along with maximum likelihood and moments estimation. The model is fitted to two real datasets and compared with alternative models for positive data. Results indicate good performance of the proposed modeÍtem Generalized modified slash Birnbaum-Saunders distribution(MDPI, 2018) Reyes, Jimmy; Barranco Chamorro, Inmaculada; Gallardo, Diego I.; Gómez, Héctor W.In this paper, a generalization of the modified slash Birnbaum–Saunders (BS) distribution is introduced. The model is defined by using the stochastic representation of the BS distribution, where the standard normal distribution is replaced by a symmetric distribution proposed by Reyes et al. It is proved that this new distribution is able to model more kurtosis than other extensions of BS previously proposed in the literature. Closed expressions are given for the pdf (probability density functio), along with their moments, skewness and kurtosis coefficients. Inference carried out is based on modified moments method and maximum likelihood (ML). To obtain ML estimates, two approaches are considered: Newton–Raphson and EM-algorithm. Applications reveal that it has potential for doing well in real problems.Ítem The Slashed-Rayleigh Fading Channel Distribution(Hindawi, 2019) Gómez Déniz, E.; Gómez, L.; Gómez, H.W.Ítem Bimodal extension based on the skew-t-normal distribution(Brazilian Statistical Association, 2019) Amiri, Mehdi; Gómez, Héctor W.; Jamalizadeh, Ahad; Towhidi, MinaIn this paper, a skew and uni-/bi-modal extension of the Student-t distribution is considered. This model is more flexible and has wider ranges of skewness and kurtosis than the other skew distributions in literature. Fisher information matrix for the proposed model and some submodels are derived. With a simulation study and some real data sets, applicability of the proposed models are illustrated.Ítem Fucoxanthin from marine microalga Isochrysis galbana: optimization of extraction methods with organic solvents•(Universidad Nacional de Colombia, 2019) Medina, Elena; Cerezal, Pedro; Morales, Juan; Ruiz Domínguez, Mari CarmenFucoxanthin was the carotenoid studied from the marine microalga Isochrysis galbana for its importance in preventing obesity and diabetes. In this manner, seven solvents were used to fucoxanthin extraction, highlighting methanol and ethanol with 6.282 and 4.187 mg/g, respectively. However, petroleum ether and n-hexane were the worst solvents for fucoxanthin extraction, obtaining approximately 12-folds less content. Extraction time was another relevant parameter in improve fucoxanthin extraction where 10 min was the best time reaching 7.464 mg/g under 100% ethanol. Finally, we propose the use of I. galbana as natural source of fucoxanthin, a bioactive compound useful for food industry.Ítem Conceptos asociados al rol profesional del médico en estudiantes de la asignatura de ‘Introducción a la Medicina’(Fundación Educación Médica, 2019) Torres Belma, Alvaro; Varas Varas, DiegoIntroducción. En la asignatura de ‘Introducción a la Medicina’, correspondiente al primer semestre del plan de estudios de la carrera de medicina de la Universidad de Antofagasta, se abordan aspectos relacionados con el papel del médico y del estudiante de medicina utilizando metodologías activas, como el aprendizaje basado en problemas y la entrevista a un paciente. Objetivo. Identificar los conceptos que el estudiante de primer año de medicina asocia con el quehacer profesional del médico cirujano. Sujetos y métodos. El diseño corresponde al de una investigación no experimental. El estudio es de carácter descriptivo. La muestra comprendió 35 estudiantes de un total de 49, lo que representa el 71,4% del total. Resultados. En la variable ‘perfil de egreso’, los conceptos experimentan diversas variaciones en relación con las características propias de las actividades de la asignatura. En la variable ‘objetivos específicos de la asignatura’, se constata que la mayoría de las respuestas se concentran en la categoría ‘totalmente de acuerdo’. Conclusiones. La visión de los estudiantes de medicina respecto al papel del médico se asocia progresivamente con los objetivos específicos planteados en el programa de la asignatura y con lo comprometido en el perfil de egreso.Ítem Atención de salud de personas transgéneros para médicos no especialistas en Chile(Sociedad Médica de Santiago, 2019) Zapata Pizarro, Antonio; Díaz Díaz, Karina; Barra Ahumada, Luis; Maureira Sales, Lorena; Linares Moreno, Jeanette; Zapata Pizarro, FrancoThe health care demand for transgenders has increased in Chile and worldwide. However, in Chile health care professionals are not trained to understand and face this problem. We herein review issues that should be considered in the training of non-specialist physicians to provide health care to transgenders, issues about terminology of body reassignment treatments and gender identity and the way Chilean professionals should deal with transgender persons.Ítem Skewness of maximum likelihood estimators in the weibull censored data(MDPI, 2019) Magalhães, Tiago M; Gallardo, Diego I.; Gómez, Héctor W.In this paper, we obtain a matrix formula of order n−1/2, where n is the sample size, for the skewness coefficient of the distribution of the maximum likelihood estimators in the Weibull censored data. The present result is a nice approach to verify if the assumption of the normality of the regression parameter distribution is satisfied. Also, the expression derived is simple, as one only has to define a few matrices. We conduct an extensive Monte Carlo study to illustrate the behavior of the skewness coefficient and we apply it in two real datasets.Ítem Serine–Arginine Protein Kinase SRPK2 Modulates the Assembly of the Active Zone Sca olding Protein CAST1/ERC2(MDPI, 2019) Arancibia, Duxan; Lira, Matias; Cruz, Yocelin; Barrera, Daniela P.; Montenegro Venegas, Carolina; Godoy, Juan A.; Garnen, Craig C.; Inestrosa, Nibaldo C.; Gundelfinger, Eckart D.; Zamorano, Pedro; Torres, Viviana I.Neurons release neurotransmitters at a specialized region of the presynaptic membrane, the active zone (AZ), where a complex meshwork of proteins organizes the release apparatus. The formation of this proteinaceous cytomatrix at the AZ (CAZ) depends on precise homo- and hetero-oligomerizations of distinct CAZ proteins. The CAZ protein CAST1/ERC2 contains four coiled-coil (CC) domains that interact with other CAZ proteins, but also promote self-assembly, which is an essential step for its integration during AZ formation. The self-assembly and synaptic recruitmentoftheDrosophilaproteinBruchpilot(BRP),apartialhomologofCAST1/ERC2,ismodulated by the serine-arginine protein kinase (SRPK79D). Here, we demonstrate that overexpression of the vertebrate SRPK2 regulates the self-assembly of CAST1/ERC2 in HEK293T, SH-SY5Y and HT-22 cells and the CC1 and CC4 domains are involved in this process. Moreover, the isoform SRPK2 forms a complex with CAST1/ERC2 when co-expressed in HEK293T and SH-SY5Y cells. More importantly, SRPK2 is present in brain synaptic fractions and synapses, suggesting that this protein kinase might control the level of self-aggregation of CAST1/ERC2 in synapses, and thereby modulate presynaptic assembly.Ítem Estudio de Diabetes Mellitus y pie diabético en la internación: Datos de Argentina(Lugones Editorial Seal of Biotecnologica SRL, 2019) Carro, Gabriela V.; Saurral, Rubén; Salvador Sagüez, Francisco; Witman, Érica L.; Carrió, Luisa Mabel; Dituro, Claudio F.; Dicatarina Losada, María Victoria; Braver, José D.; Illuminati, Gabriela; Torres, Julio C.; David, Raúl A.; Maldonado, NatachaIntroducción: el pie diabético es una complicación que se pre-senta del 15 al 25% de los pacientes con diabetes mellitus (DM) a lo largo de su vida. Una vez que aparece, demanda un abordaje multidisciplinario y a menudo requiere internación. Estas internaciones suelen ser prolongadas y costosas dado que para su atención se necesitan complejos procedimientos de diagnóstico y tratamiento. En este contexto, el conocimiento de los datos acerca de la internación de pacientes con pie diabético es importante al momento de tomar decisiones de salud pública e implementar acciones para la prevención, derivación temprana, referencia y contrarreferencia de pacientes.Objetivos: el objetivo de este estudio fue determinar la prevalencia de DM y la tasa de pie diabético (PD) en pacientes internados.Materiales y métodos: se estudiaron 6.776 pacientes internados en 104 instituciones argentinas. El estudio se realizó durante un día elegido por cada institución dentro de un lapso de dos meses (septiembre y octubre de 2017).Resultados: la prevalencia de DM fue de 17,86% y la tasa de PD 14,11%. La tasa de pie diabético con lesiones Wagner 1 o mayor fue de 4,47%. El pie diabético fue el motivo de internación en el 3,16% del total de internados y al 17,85% de los diabéticos internados.Conclusiones: en nuestro conocimiento, este trabajo es el primero realizado en Argentina que abarca ese tamaño muestral y sienta precedente para nuevos trabajos de investigación en el temaÍtem Metagenomics of Atacama Lithobiontic Extremophile Life Unveils Highlights on Fungal Communities, Biogeochemical Cycles and Carbohydrate-Active Enzymes(MDPI, 2019) Gómez Silva, Benito; Vilo-Muñoz, Claudia; Galetović, Alexandra; Dong, Qunfeng; Castelán-Sánchez, Hugo G.; Pérez-Llano, Yordanis; Sánchez-Carbente, María del Rayo; Dávila-Ramos, Sonia; Cortés-López, Nohemí Gabriela; Martínez-Ávila, Liliana; Dobson, Alan D. W.; Batista-García, Ramón AlbertoHalites, which are typically found in various Atacama locations, are evaporitic rocks that are considered as micro-scaled salterns. Both structural and functional metagenomic analyses of halite nodules were performed. Structural analyses indicated that the halite microbiota is mainly composed of NaCl-adapted microorganisms. In addition, halites appear to harbor a limited diversity of fungal families together with a biodiverse collection of protozoa. Functional analysis indicated that the halite microbiome possesses the capacity to make an extensive contribution to carbon, nitrogen, and sulfur cycles, but possess a limited capacity to fix nitrogen. The halite metagenome also contains a vast repertory of carbohydrate active enzymes (CAZY) with glycosyl transferases being the most abundant class present, followed by glycosyl hydrolases (GH). Amylases were also present in high abundance, with GH also being identified. Thus, the halite microbiota is a potential useful source of novel enzymes that could have biotechnological applicability. This is the first metagenomic report of fungi and protozoa as endolithobionts of halite nodules, as well as the first attempt to describe the repertoire of CAZY in this community. In addition, we present a comprehensive functional metagenomic analysis of the metabolic capacities of the halite microbiota, providing evidence for the first time on the sulfur cycle in Atacama halites.Ítem Habilidades pedagógicas en docentes cirujanos de la carrera de medicina de la Universidad de Antofagasta(Fundación Educación Médica, 2019) Álvarez Iguaín, Claudia; Becerra Mellado, Natalia; Díaz Díaz, Karina; Torres Belma, AlbertoIntroducción. Como parte de las actividades de perfeccionamiento académico del departamento de Ciencias Médicas, se aplicó un cuestionario a médicos especialistas en cirugía de la carrera de medicina de la universidad de antofagasta que desarrollan actividades curriculares en el ámbito clínico o teórico en el internado de cirugía y asignaturas clínicas del plan de estudios, con el fin de caracterizar su experiencia en docencia universitaria. Sujetos y métodos. Estudio cuantitativo transversal de carácter exploratorio y descriptivo, en el que participaron 13 médicos cirujanos especialistas que cumplen labores docentes en el internado de cirugía y asignaturas clínicas de la carrera de medicina de la universidad de antofagasta. El procedimiento de recogida de información consistió en una encuesta descriptiva. Resultados. la mayoría de los docentes posee trayectoria en docencia entre 1 y 15 años; no obstante, es importante realizar perfeccionamiento académico considerando que un 53,8% refiere no poseer capacitaciones en docencia, lo que se refleja en una mayor utilización de estrategias de aprendizaje y de evaluación tradicionales. además, las necesidades de capacitación aluden a estrategias metodológicas de enseñanza y de evaluación. Conclusión. la investigación realizada da cuenta de la oportunidad del departamento de Ciencias Médicas para capacitar en habilidades pedagógicas a sus docentes médicos especialistas en cirugía, para la adopción de estrategias metodológicas y evaluativas centradas en el estudianteÍtem Contribution of Fcy Receptor-Mediated Immunity to the Pathogenesis Caused by the Human Respiratory Syncytial Virus(Frontiers Media S.A, 2019) Acevedo, Orlando A.; Díaz, Fabián E; Beals, Tomas E.; Benavente, Felipe M.; Soto, Jorge A.; Escobar Vera, Jorge; González, Pablo A.; Kalergis, Alexis M.The human Respiratory Syncytial Virus (hRSV) is the leading cause of severe acute lower respiratory tract infections (ALRTIs) in humans at all ages and is the main cause of hospitalization due to pneumonia, asthma, and bronchiolitis in infants. hRSV symptoms mainly develop due to an excessive host immune and inflammatory response in the respiratory tissue. hRSV infection during life is frequent and likely because of non-optimal immunological memory is developed against this virus. Vaccine development against this pathogen has been delayed after the detrimental effects produced in children by vaccination with a formalin-inactivated hRSV preparation (FI-hRSV), which caused enhanced disease upon natural viral infection. Since then, several studies have focused on understanding the mechanisms underlying such disease exacerbation. Along these lines, several studies have suggested that antibodies elicited by immunization with FI-hRSV show low neutralizing capacity and promote the formation of immune complexes containing hRSV (hRSV-ICs), which contribute to hRSV pathogenesis through the engagement of Fc gamma receptors (FcγRs) expressed on the surface of immune cells. Furthermore, a role for FcγRs is supported by studies evaluating the contribution of these molecules to hRSV-induced disease. These studies have shown that FcγRs can modulate viral clearance by the host and the inflammatory response triggered by hRSV infection. In addition, ICs can facilitate viral entry into host cells expressing FcγRs, thus extending hRSV infectivity. In this article, we discuss current knowledge relative to the contribution of hRSV-ICs and FcγRs to the pathogenesis caused by hRSV and their putative role in the exacerbation of the disease caused by this virus after FI-hRSV vaccination. A better understanding FcγRs involvement in the immune response against hRSV will contribute to the development of new prophylactic or therapeutic tools to promote virus clearance with limited inflammatory damage to the airwaysÍtem Observational cross-sectional study of Trichomonas tenax in patients with periodontal disease attending a Chilean university dental clinic(BioMed Central, 2019) Bracamonte Wolf, Casandra; Orrego, Patricio R.; Muñoz, Christian; Herrera, Daniel; Bravo, Joel; Gonzalez, Jorge; Varela, Héctor; Catalán, Alejandro; Araya, Jorge E.Background: The oral flagellated protozoan Trichomonas tenax has been associated with patients with periodontal disease. However, no recent studies have been conducted on the prevalence of T. tenax in Chile. The aim of this study was to determine the presence of T. tenax in patients with periodontal disease, admitted to the Dental Clinic of the University of Antofagasta, Chile, through Polymerase Chain Reaction (PCR) amplification of the beta-tubulin gene. Methods: An observational, cross-sectional study was conducted on 50 patients diagnosed with periodontal disease, 20 of them with gingivitis and 30 with periodontitis. T. tenax was identified by PCR amplification of the beta-tubulin gene. Associations between the protozoan and periodontal disease or the presence of risk factors to establish T. tenax infection were determined using the chi-square test and binary logistic regression analysis. Results: T. tenax was present in 28 out of 50 (56%) of patients with periodontal disease, and was more prevalent when associated with periodontitis (21 out of 30; 70%) than dental plaque-induced gingivitis (7 out of 20; 35%). Non-statistically-significant associations were observed between the presence of T. tenax and age, gender, smoking habit or diabetes. Statistically significant associations were observed between the presence of T. tenax and periodontal disease, and between T. tenax and the Periodontal Screening and Recording (PSR) index. Conclusion: T. tenax showed a high presence in patients with progressive states of periodontal diseases. Consequently, T. tenax detection is strongly recommended in patients with periodontal disease diagnosis and with a PSR index greater than 3.Ítem A Regenerative Endodontic Approach in Mature Ferret Teeth Using Rodent Preameloblast-conditioned Medium(Instituto Internacional de Investigación Anticancerígena, 2019) Bucchi, Cristina; Gimeno-Sandig, Álvaro; Valdivia Gandur, Ívan; Céspedes-Manzanares, Cristina; Maria de Anta, JosepBackground: This study evaluated the effectiveness of a regenerative endodontic approach to regenerate the pulp tissue in mature teeth of ferret. The presence of odontoblastlike cells in the newly-formed tissue of teeth treated with or without preameloblast-conditioned medium was evaluated based on morphological criteria. Materials and Methods: Twenty-four canines from six ferrets were treated. The pulp was removed, and the apical foramen was enlarged. After inducing the formation of a blood clot, a collagen sponge with or without preameloblast-conditioned medium was placed underneath the cementoenamel junction. The samples were analyzed at the eighth week of follow-up. Results: Vascularized connective tissue was observed in 50% of teeth, without differences between groups. The tissue occupied the apical third of the root canals. Odontoblast-like cells were not observed in any group. Conclusion: Revitalization of mature teeth is possible, at least in the apical third of the root canal. Further experimental research is needed to produce more reliable outcomes.Ítem Flexible Birnbaum-Saunders distribution(MDPI, 2019) Martínez Flórez, Guillermo; Barranco Chamorro, Inmaculada; Bolfarine, Heleno; Gómez, HectorW.In this paper, we propose a bimodal extension of the Birnbaum–Saunders model by including an extra parameter. This new model is termed flexible Birnbaum–Saunders (FBS) and includes the ordinary Birnbaum–Saunders (BS) and the skew Birnbaum–Saunders (SBS) model as special cases. Its properties are studied. Parameter estimation is considered via an iterative maximum likelihood approach. Two real applications, of interest in environmental sciences, are included, which reveal that our proposal can perform better than other competing models.Ítem Application of microencapsulated anthocyanin extracted from purple cabbage in fermented milk drinks(Universidad Nacional de Colombia, 2019) Espinosa Álvarez, Carolina; López Contreras, Javiera; Escobar Rodríguez, Darling; Jiménez Rondón, Diana; Bugueño Muñoz, Waldo; Cerezal Mezquita, PedroMicroencapsulation protects different bioactive compounds (anthocyanins) from environmental factors, increasing their half-life. In this study, the extraction and microencapsulation conditions for purple cabbage anthocyanins were determined, in addition to stability of the natural pigment obtained in a fermented milk beverage. Scalded was used for enzymatic inactivation in purple cabbage (Brassica oleracea L. ssp. Capitata f. Rubra) leaves, the extraction of bioactive compounds was carried out using green technologies (microwaves), concentrating the anthocyanin solution and mixing with wall materials such as maltodextrin, inulin and gum arabic for microencapsulation and addition to fermented milk beverage. The color stability was determined for 8 days; the ΔE of the beverage was slightly perceptible by the human eye. The concentration of anthocyanins was 199 mg/L with a solution of water and 2% acidified ethyl alcohol at 880 W of power for 90 s; the best drying performance was 58.9%.