bluuebunny/crossref_metadata_2025 huggingface dataset:
New Techniques for Seed Shape Description in Silene Species
Authors: Juan Ana , Martín-Gómez José Javier , Rodríguez-Lorenzo José Luis , Janoušek Bohuslav , Cervantes Emilio
Published: December 2021

Seed shape in Silene species is often described by means of adjectives such as reniform, globose, and orbicular, but the application of seed shape for species classification requires quantification. A method for the description and quantification of seed shape consists in the comparison with geometric models. Geometric models based on mathematical equations were applied to characterize the general morphology of the seeds in 21 species of Silene. In addition to the previously described four models (M1 is the cardioid, and M2 to M4 are figures derived from it), we present four new geometric models (model 5–8). Models 5 and 6 are open cardioids that resemble M3, quite different from the flat models, M2 and M4. Models 7 and 8 were applied to those species not covered by models 2 to 6. Morphological measures were obtained to describe and characterize the dorsal view of the seeds. The analyses done on dorsal views revealed a notable morphological diversity and four groups were identified. A correlation was found between roundness of dorsal view and the geometric models based on lateral views, such that some of the groups defined by seed roundness are also characterized by the similarity to particular models. The usefulness of new morphological tools of seed morphology to taxonomy is discussed.
Two New Species of Pristimantis (Anura: Strabomantidae) from Amazonas Department in Northeastern Peru
Authors: Venegas Pablo J. , García-Ayachi Luis A. , Catenazzi Alessandro
Published: December 2021

We describe two new species of terrestrial-breeding frogs in the genus Pristimantis from the Andes of northeastern Peru, Amazonas Department. Both species share several characters with other congeners from northern Peru, such as the presence of prominent conical tubercles on their eyelids and heel, prominent conical tubercles along the outer edge of the tarsus, and discs on fingers and toes widely expanded. However, both species can be diagnosed from morphologically similar Pristimantis in the region. Pristimantis kiruhampatu has axillae, groins, and hidden surfaces of hindlimbs that are cherry with white minute flecks, tympanic membrane and tympanic annulus evident, conical tubercles along the edge of snout and outer edge of tibia, and \/ shaped folds in the scapular region. Pristimantis paulpittmani has yellow or dirty cream groins and hidden surfaces of hindlimbs, whitish cream irises with scattered dark brown reticulations, and a thin vertical dark brown streak at the middle of the eye, snout subacuminate with a conical tubercle at the tip, and lacks a tympanic annulus and membrane. Additionally, we provide a short description of the advertisement call of P. kiruhampatu.
Feasibility of Magnetic Resonance Fingerprinting on Aging MRI Hardware
Authors: Eck Brendan Lee , Liu Kecheng , Lo Wei-ching , Jiang Yun , Gulani Vikas , Seiberlich Nicole
Published: December 2021

The purpose of this work is to evaluate the feasibility of performing magnetic resonance fingerprinting (MRF) on older and lower-performance MRI hardware as a means to bring advanced imaging to the aging MRI install base. Phantom and in vivo experiments were performed on a 1.5T Siemens Aera (installed 2015) and 1.5T Siemens Symphony (installed 2002). A 2D spiral MRF sequence for simultaneous T1/T2/M0 mapping was implemented on both scanners with different gradient trajectories to accommodate system specifications. In phantom, for T1/T2 values in a physiologically relevant range (T1: 195–1539 ms; T2: 20–267 ms), scanners had strong correlation (R2 > 0.999) with average absolute percent difference of 8.1% and 10.1%, respectively. Comparison of the two trajectories on the newer scanner showed differences of 2.6% (T1) and 10.9% (T2), suggesting a partial explanation of the observed inter-scanner bias. Inter-scanner agreement was better when the same trajectory was used, with differences of 6.0% (T1) and 4.0% (T2). Intra-scanner coefficient of variation (CV) of T1 and T2 estimates in phantom were <2.0% and in vivo were ≤3.5%. In vivo inter-scanner white matter CV was 4.8% (T1) and 5.1% (T2). White matter measurements on the aging scanner after two months were consistent, with differences of 1.9% (T1) and 3.9% (T2). In conclusion, MRF is feasible on an aging MRI scanner and required only changes to the gradient trajectory.
Influence of Prolonged Serotonin and Ergovaline Pre-Exposure on Vasoconstriction Ex Vivo
Authors: Valente Eriton E. L. , Harmon David L. , Klotz James L.
Published: December 2021

Ergot alkaloid mycotoxins interfere in many functions associated with serotonergic neurotransmitters. Therefore, the objective was to evaluate whether the association of serotonin (5-hydroxytryptamine, 5-HT) and ergot alkaloids during a 24 h pre-incubation could affect the vascular contractile response to ergot alkaloids. To evaluate the effects of 24 h exposure to 5-HT and ergot alkaloids (ergovaline, ERV), two assays were conducted. The first assay determined the half-maximal inhibitory concentration (IC50) following the 24 h pre-exposure period, while the second assay evaluated the effect of IC50 concentrations of 5-HT and ERV either individually or in combination. There was an interaction between previous exposure to 5-HT and ERV. Previous exposure to 5-HT at the IC50 concentration of 7.57 × 10−7 M reduced the contractile response by more than 50% of control, while the exposure to ERV at IC50 dose of 1.57 × 10−10 M tended to decrease (p = 0.081) vessel contractility with a response higher than 50% of control. The 24 h previous exposure to both 5-HT and ERV did not potentiate the inhibitory response of blood vessels in comparison with incubation with each compound alone. These results suggest receptor competition between 5-HT and ERV. More studies are necessary to determine the potential of 5-HT to treat toxicosis caused by ergot alkaloids.
Structural Analysis of Botulinum Neurotoxins Type B and E by Cryo-EM
Authors: Košenina Sara , Martínez-Carranza Markel , Davies Jonathan R. , Masuyer Geoffrey , Stenmark Pål
Published: December 2021

Botulinum neurotoxins (BoNTs) are the causative agents of a potentially lethal paralytic disease targeting cholinergic nerve terminals. Multiple BoNT serotypes exist, with types A, B and E being the main cause of human botulism. Their extreme toxicity has been exploited for cosmetic and therapeutic uses to treat a wide range of neuromuscular disorders. Although naturally occurring BoNT types share a common end effect, their activity varies significantly based on the neuronal cell-surface receptors and intracellular SNARE substrates they target. These properties are the result of structural variations that have traditionally been studied using biophysical methods such as X-ray crystallography. Here, we determined the first structures of botulinum neurotoxins using single-particle cryogenic electron microscopy. The maps obtained at 3.6 and 3.7 Å for BoNT/B and /E, respectively, highlight the subtle structural dynamism between domains, and of the binding domain in particular. This study demonstrates how the recent advances made in the field of single-particle electron microscopy can be applied to bacterial toxins of clinical relevance and the botulinum neurotoxin family in particular.
Design of New Resonant Haloscopes in the Search for the Dark Matter Axion: A Review of the First Steps in the RADES Collaboration
Authors: Díaz-Morcillo Alejandro , García Barceló José María , Lozano Guerrero Antonio José , Navarro Pablo , Gimeno Benito , Arguedas Cuendis Sergio , Álvarez Melcón Alejandro , Cogollos Cristian , Calatroni Sergio , Döbrich Babette , Gallego-Puyol Juan Daniel , Golm Jessica , Irastorza Igor García , Malbrunot Chloe , Miralda-Escudé Jordi , Peña Garay Carlos , Redondo Javier , Wuensch Walter
Published: December 2021

With the increasing interest in dark matter axion detection through haloscopes, in which different international groups are currently involved, the RADES group was established in 2016 with the goal of developing very sensitive detection systems to be operated in dipole magnets. This review deals with the work developed by this collaboration during its first five years: from the first designs—based on the multi-cavity concept, aiming to increase the haloscope volume, and thereby improve sensitivity—to their evolution, data acquisition design, and finally, the first experimental run. Moreover, the envisaged work within RADES for both dipole and solenoid magnets in the short and medium term is also presented.
Neutron Stars in the Symmetron Model
Authors: de Aguiar Bernardo F. , Mendes Raissa F. P. , Falciano Felipe T.
Published: December 2021

Screening mechanisms are often deployed by dark energy models to conceal the effects of their new degrees of freedom from the scrutiny of terrestrial and solar system experiments. However, the extreme properties of nuclear matter may lead to a partial failure of screening mechanisms inside the most massive neutron stars observed in nature, opening up the possibility of probing these theories with neutron star observations. In this work, we explore equilibrium and stability properties of neutron stars in two variants of the symmetron model. We show that around sufficiently compact neutron stars, the symmetron is amplified with respect to its background (cosmological) value by several orders of magnitude, and that the properties of such unscreened stars are sensitive to corrections to the leading linear coupling between the symmetron and matter.
Dengue Infection Susceptibility of Five Aedes aegypti Populations from Manaus (Brazil) after Challenge with Virus Serotypes 1–4
Authors: Chaves Bárbara Aparecida , Godoy Raquel Soares Maia , Campolina Thaís Bonifácio , Júnior Ademir Bentes Vieira , Paz Andréia da Costa , Vaz Evelyn Beatriz da Costa , Silva Breno Mello , Nascimento Rêgila Mello , Guerra Maria das Graças Vale Barbosa , Lacerda Marcus Vinicius Guimarães , Monteiro Wuelton Marcelo , Secundino Nágila Francinete Costa , Pimenta Paulo Filemon Paolucci
Published: December 2021

The successful spread and maintenance of the dengue virus (DENV) in mosquito vectors depends on their viral infection susceptibility, and parameters related to vector competence are the most valuable for measuring the risk of viral transmission by mosquitoes. These parameters may vary according to the viral serotype in circulation and in accordance with the geographic origin of the mosquito population that is being assessed. In this study, we investigated the effect of DENV serotypes (1–4) with regards to the infection susceptibility of five Brazilian Ae. aegypti populations from Manaus, the capital of the state of Amazonas, Brazil. Mosquitoes were challenged by oral infection with the DENV serotypes and then tested for the presence of the arbovirus using quantitative PCR at 14 days post-infection, which is the time point that corresponds to the extrinsic incubation period of Ae. aegypti when reared at 28 °C. Thus, we were able to determine the infection patterns for DENV-1, -2, -3 and -4 in the mosquito populations. The mosquitoes had both interpopulation and inter-serotype variation in their viral susceptibilities. All DENV serotypes showed a similar tendency to accumulate in the body in a greater amount than in the head/salivary gland (head/SG), which does not occur with other flaviviruses. For DENV-1, DENV-3, and DENV-4, the body viral load varied among populations, but the head/SG viral loads were similar. Differently for DENV-2, both body and head/SG viral loads varied among populations. As the lack of phenotypic homogeneity represents one of the most important reasons for the long-term fight against dengue incidence, we expect that this study will help us to understand the dynamics of the infection patterns that are triggered by the distinct serotypes of DENV in mosquitoes.
Identification of the Human Papillomavirus Genotypes, According to the Human Immunodeficiency Virus Status in a Cohort of Women from Maputo, Mozambique
Authors: Maueia Cremildo , Murahwa Alltalents , Manjate Alice , Andersson Soren , Sacarlal Jahit , Kenga Darlene , Mussá Tufária , Williamson Anna-Lise
Published: December 2021

Background: Human papillomavirus (HPV) infection is now a well-established cause of cervical cancer and other anogenital cancers. An association between human immunodeficiency virus (HIV) infection and higher HPV incidence and prevalence are commonly reported. This study was conducted to demonstrate HPV prevalence, genotypes and its characteristics, according to the HIV status in women from Maputo in Mozambique. Methods: A total of 233 participants with ages ranging from fourteen to forty-five were included. Cervical samples were collected, DNA extracted, and HPV genotyping was performed using the HPV Direct Flow CHIP Kit. Results: In total, 177 HIV-negative and 56 HIV-positive women were included in the analysis. The overall HPV prevalence was 63% and was significantly higher among HIV-positive women (79% versus 58% among HIV-negative women; p = 0.005). The prevalence of multiple HPV type infections was 32%. High-risk HPV types 52, 68, 35, 18 and 16 were the most frequent. A higher proportion of HIV-positive women had multiple HPV types compared with HIV-negative women. Conclusions: This study demonstrated a high prevalence of HPV in the study cohort. HIV-positive women were identified as having the highest HPV prevalence and infection with multiple HPV types across all ages. High-risk genotypes were the most commonly found.
Pandemics of the 21st Century: The Risk Factor for Obese People
Authors: Hancková Miriam , Betáková Tatiana
Published: December 2021

The number of obese adults and children is increasing worldwide, with obesity now being a global epidemic. Around 2.8 million people die annually from clinical overweight or obesity. Obesity is associated with numerous comorbid conditions including hypertension, cardiovascular disease, type 2 diabetes, hypercholesterolemia, hypertriglyceridemia, nonalcoholic fatty liver disease, and cancer, and even the development of severe disease after infection with viruses. Over the past twenty years, a number of new viruses has emerged and entered the human population. Moreover, influenza (H1N1)pdm09 virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have caused pandemics. During pandemics, the number of obese patients presents challenging and complex issues in medical and surgical intensive care units. Morbidity amongst obese individuals is directly proportional to body mass index. In this review, we describe the impact of obesity on the immune system, adult mortality, and immune response after infection with pandemic influenza virus and SARS-CoV-2. Finally, we address the effect of obesity on vaccination.
Vaccination Hesitancy among Health-Care-Workers in Academic Hospitals Is Associated with a 12-Fold Increase in the Risk of COVID-19 Infection: A Nine-Month Greek Cohort Study
Authors: Ntziora Fotinie , Kostaki Evangelia Georgia , Grigoropoulos Ioannis , Karapanou Amalia , Kliani Ismini , Mylona Maria , Thomollari Alexa , Tsiodras Sotirios , Zaoutis Theoklis , Paraskevis Dimitrios , Sipsas Nikolaos V. , Antoniadou Anastasia , Sfikakis Petros P.
Published: December 2021

Health-Care-Workers (HCWs) are considered at high risk for SARS-CoV-2 infection. We sought to compare rates and severity of Coronavirus disease 2019 (COVID-19) among vaccinated and unvaccinated HCWs conducting a retrospective cohort study in two tertiary Academic Hospitals, namely Laiko and Attikon, in Athens, Greece. Vaccinated by BNT162b2 Pfizer-BioNTech COVID-19 mRNA vaccine and unvaccinated HCWs were included and data were collected between 1 January 2021 and 15 September 2021. Overall, 2921 of 3219 HCWs without a history of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection were fully vaccinated during the study period (90.7% at each Hospital). Demographic characteristics were comparable between 102/2921 (3.5%) vaccinated and 88/298 (29.5%) unvaccinated HCWs with COVID-19, although age and occupation differed significantly. None were in need of hospital admission in the vaccinated Group, whereas in the unvaccinated Group 4/88 (4.5%) were hospitalized and one (1.1%) died. Multivariable logistic regression analysis revealed that lack of vaccination was an independent risk factor for COVID-19 with an odds ratio 11.54 (95% CI: 10.75–12.40). Vaccination hesitancy among HCWs resulted to highly increased COVID-19 rates; almost one in three unvaccinated HCWs was SARS-CoV-2 infected during the 9-month period. The absolute need of vaccination of HCWs, including boosting dose, is highlighted. Evidence should be used appropriately to overcome any hesitancy.
The Signal Peptide and Chaperone UNC93B1 Both Influence TLR8 Ectodomain Intracellular Endosomal Localization
Authors: Ao Da , Liu Xueliang , Jiang Sen , Xu Yulin , Zheng Wanglong , Chen Nanhua , Meurens François , Zhu Jianzhong
Published: December 2021

Toll-like receptor 8 (TLR8) is a single-stranded RNA sensing receptor and is localized in the cellular compartments, where it encounters foreign or self-nucleic acids and activates innate and adaptive immune responses. However, the mechanism controlling intracellular localization TLR8 is not completely resolved. We previously revealed the intracellular localization of TLR8 ectodomain (ECD), and in this study, we investigated the mechanism of the intracellular localization. Here we found that TLR8 ECDs from different species as well as ECDs from different TLRs are all intracellularly localized, similarly to the full-length porcine TLR8. Furthermore, porcine, bovine, and human TLR8 ECDs are all localized in cell endosomes, reflecting the cellular localization of TLR8. Intriguingly, none of post-translational modifications at single sites, including glycosylation, phosphorylation, ubiquitination, acetylation, and palmitoylation alter porcine TLR8-ECD endosomal localization. Nevertheless, the signal peptide of porcine TLR8-ECD determines its endosomal localization. On the other hand, signaling regulator UNC93B1 also decides the endosomal localization of porcine, bovine, and human TLR8 ECDs. The results from this study shed light on the mechanisms of not only TLR8 intracellular localization but also the TLR immune signaling.
Factors Associated with Adverse Reactions to BNT162b2 COVID-19 Vaccine in a Cohort of 3969 Hospital Workers
Authors: Rivera-Izquierdo Mario , Soler-Iborte Eva , de Rojas Javier Pérez , Pegalajar-García María Dolores , Gil-Villalba Ana , Ruiz-Villaverde Ricardo , Valero-Ubierna María del Carmen
Published: December 2021

Factors associated with adverse reactions to BNT162b2 COVID-19 vaccine reported by hospital workers are unclear. Our aim was to collect all reported adverse events in a cohort of hospital workers and to analyze the factors associated with their presence. We conducted an observational longitudinal study on all hospital workers of our center who received COVID-19 vaccination from 27 December 2020 to 1 September 2021. Information on adverse events was reported telephonically and confirmed through clinical records. Chi-square and t tests as well as multivariate logistic regression models were used. Cluster analysis was designed to explore associations between reactions. A total of 3969 hospital workers were included in the sample. Of the total sample, 182 workers (4.6%) reported adverse events. The most frequent symptoms were general malaise (n = 95), fever (n = 92), arthromyalgia (n = 80), and headache (n = 47). The factors associated with adverse events in adjusted analyses were an antecedent of COVID-19 infection (OR = 2.09, 95% CI: 1.47–2.98), female sex (OR = 1.51, 95% CI: 1.03–2.20), and professional category (OR for physicians = 0.41, 95% CI: 0.21–0.80). We report a low frequency of adverse events in hospital workers after COVID-19 vaccination and no severe reaction. Men and physicians underreported their symptoms. These data should guide future strategies for recording adverse events and future research on COVID-19 vaccination safety.
COVID-19 Seroprevalence in Canada Modelling Waning and Boosting COVID-19 Immunity in Canada a Canadian Immunization Research Network Study
Authors: Dick David W. , Childs Lauren , Feng Zhilan , Li Jing , Röst Gergely , Buckeridge David L. , Ogden Nick H. , Heffernan Jane M.
Published: December 2021

COVID-19 seroprevalence changes over time, with infection, vaccination, and waning immunity. Seroprevalence estimates are needed to determine when increased COVID-19 vaccination coverage is needed, and when booster doses should be considered, to reduce the spread and disease severity of COVID-19 infection. We use an age-structured model including infection, vaccination and waning immunity to estimate the distribution of immunity to COVID-19 in the Canadian population. This is the first mathematical model to do so. We estimate that 60–80% of the Canadian population has some immunity to COVID-19 by late Summer 2021, depending on specific characteristics of the vaccine and the waning rate of immunity. Models results indicate that increased vaccination uptake in age groups 12–29, and booster doses in age group 50+ are needed to reduce the severity COVID-19 Fall 2021 resurgence.
Characterization of Fructose-1,6-Bisphosphate Aldolase 1 of Echinococcus multilocularis
Authors: He Xuedong , Zhang Jing , Sun Yue , Lan Tianyan , Guo Xiaola , Wang Xiaoqiang , Kandil Omnia M. , Ayaz Mazhar , Luo Xuenong , Song Houhui , Zheng Yadong
Published: December 2021

Glycolysis is one of the important ways by which Echinococcus multilocularis acquires energy. Fructose-1, 6-bisphosphate aldolase (FBA) plays an important role in this process, but it is not fully characterized in E. multilocularis yet. The results of genome-wide analysis showed that the Echinococcus species contained four fba genes (FBA1-4), all of which had the domain of FBA I and multiple conserved active sites. EmFBA1 was mainly located in the germinal layer and the posterior of the protoscolex. The enzyme activity of EmFBA1 was 67.42 U/mg with Km and Vmax of 1.75 mM and 0.5 mmol/min, respectively. EmFBA1 was only susceptible to Fe3+ but not to the other four ions (Na+, Ca2+, K+, Mg2+), and its enzyme activity was remarkably lost in the presence of 0.5 mM Fe3+. The current study reveals the biochemical characters of EmFBA1 and is informative for further investigation of its role in the glycolysis in E. multilocularis.
Spatial–Temporal Distribution of Phosphorus Fractions and Their Relationship in Water–Sediment Phases in the Tuojiang River, China
Authors: Liu Dandan , Li Xueying , Zhang Yue , Lu Zhibo , Bai Lu , Qiao Qi , Liu Jingyang
Published: December 2021

Understanding the distribution and transportation of phosphorus is vital for the sustainable development of aquatic environmental protection and ecological security. The spatial–temporal distribution of phosphorus fractions in water–sediment phases in river systems and their relationships remain unclear in Southwest China. In this study, the spatial and temporal distribution of phosphorus fractions in water–sediment phases in the Tuojiang River, a primary tributary of the Yangtze River which plays important roles in the economy and ecology of the region, and the relationships among the different phosphorus fractions were analyzed. These fractions were soluble reactive phosphorus (SRP), dissolved organic phosphorus (DOP), and total particulate phosphorus (PP) fractions in water, and exchangeable phosphorus (Ex-P), organic phosphorus (Or-P), phosphorus bound by Fe oxides (Fe-P), authigenic phosphorus (Ca-P), detrital phosphorus (De-P), and refractory phosphorus (Res-P) fractions in sediment. The SPR and Fe-P were the dominant phosphorus fractions in the water and sediment, respectively. The TP content was greater in the lower reaches than in the middle and upper reaches. The average abundances of most phosphorus fractions in water–sediment phases showed significant seasonal variations. The Fe-P, Org-P, and TP in sediments were released to the water interface, resulting in the increase of phosphorus in the overlying water. Redundancy analysis (RDA) indicated that the physicochemical properties of water and sediment have a certain influence on the spatial–temporal distribution of the phosphorus fractions. Principal component analysis (PCA) revealed that the main phosphorus source was anthropogenic activities. These results provide primary data regarding phosphorus fractions and contribute to understanding phosphorus cycling and controlling phosphorus pollution in the Tuojiang River.
Salinity Contributions from Geothermal Waters to the Rio Grande and Shallow Aquifer System in the Transboundary Mesilla (United States)/Conejos-Médanos (Mexico) Basin
Authors: Pepin Jeff D. , Robertson Andrew J. , Kelley Shari A.
Published: December 2021

Freshwater scarcity has raised concerns about the long-term availability of the water supplies within the transboundary Mesilla (United States)/Conejos-Médanos (Mexico) Basin in Texas, New Mexico, and Chihuahua. Analysis of legacy temperature data and groundwater flux estimates indicates that the region’s known geothermal systems may contribute more than 45,000 tons of dissolved solids per year to the shallow aquifer system, with around 8500 tons of dissolved solids being delivered from localized groundwater upflow zones within those geothermal systems. If this salinity flux is steady and eventually flows into the Rio Grande, it could account for 22% of the typical average annual cumulative Rio Grande salinity that leaves the basin each year—this salinity proportion could be much greater in times of low streamflow. Regional water level mapping indicates upwelling brackish waters flow towards the Rio Grande and the southern part of the Mesilla portion of the basin with some water intercepted by wells in Las Cruces and northern Chihuahua. Upwelling waters ascend from depths greater than 1 km with focused flow along fault zones, uplifted bedrock, and/or fractured igneous intrusions. Overall, this work demonstrates the utility of using heat as a groundwater tracer to identify salinity sources and further informs stakeholders on the presence of several brackish upflow zones that could notably degrade the quality of international water supplies in this developed drought-stricken region.
LLC DC-DC Converter Performances Improvement for Bidirectional Electric Vehicle Charger Application
Authors: Al Attar Houssein , Hamida Mohamed Assaad , Ghanes Malek , Taleb Miassa
Published: December 2021

Electric Vehicle (EV) bidirectional charger technology is growing in importance. It defines the fact of returning the electricity stored in the batteries of EV to Grid (V2G), to Home (V2H), to Load (V2L), or in one word V2X mode. The EV onboard charger is divided into two parts: AC-DC and DC-DC converters. The isolated bidirectional DC-DC LLC resonant converter is used to improve the charger efficiency within both battery power and voltage ranges. It is controlled by varying the switching frequency based on a small signal modeling approach using the gain transfer function inversion method. The dimensions of the DC-DC LLC converter directly affect the charger cost. Moreover, they cause an important control frequency saturation zone, especially in V2X mode, where the switching frequency is out of the feasibility zone. The new challenge in this paper is to design an optimization strategy to minimize the LLC converter cost and improve the control frequency feasibility zone, for a wide variation of battery voltage and converter power, in the charging (G2V) and discharging (V2X) modes simultaneously. For our best knowledge, this optimization problem, in the case of a bidirectional (G2V and V2X) charger, is not yet considered in the literature. An optimal design that considers the control stability equations in the optimization algorithm is elaborated. The obtained results show a significant converter cost decrease and important expansion of control frequency feasibility zones. A comparative study between initial and optimized values, in G2V and V2X modes, is generated according to the converter efficiency.
El desafío de las nuevas tecnologías: el uso del aula virtual y su influencia en el rendimiento académico.
Authors: Gómez Vera Katherine
Published: December 2021

Las aulas virtuales han venido a revolucionar el contexto educativo, muchas veces se ha confundido el empleo de una aplicación determinada con este tipo de escenarios, pero la realidad, es que el aula virtual tiene un contexto de aprendizaje bien definido, que requiere la predisposición de los docentes y una óptima preparación de los estudiantes. El auge de las nuevas tecnologías de la información y la comunicación exige, que los profesores tengan conocimientos más actualizados sobre el tema y diseñen aulas virtuales que tengan como propósito complementar el aprendizaje presencial, así como también sé definan nuevos procedimientos y prácticas para la construcción del conocimiento. Una de las ventajas es que con la aplicación de este proceso el aprendizaje, se da de forma autónoma y permite a los estudiantes acceder a recursos educativos a través de internet. En este sentido, el objetivo de este trabajo académico es analizar, la forma en que este tipo de innovadoras estrategias educativas, aplicadas por el docente influyen en el rendimiento académico de los alumnos, y dio como resultado que el uso de las aulas virtuales mejoran el aprendizaje de los estudiantes, donde así mismo se corroboro que la mayoría de los estudiantes no tiene un conocimiento adecuado del uso de las aulas virtuales y que los educadores no han podido enseñar a los alumnos las ventajas que tienen las mismas en el proceso educativo. Los materiales de estudio, la interacción con los usuarios, el maestro, el acceso a diversas plataformas son algunas de las ventajas y beneficios con que cuentan las aulas virtuales. Con ello el proceso de enseñanza- aprendizaje se convierte en una práctica personalizada en la que los participantes encuentran una motivación mayor para acceder al conocimiento disponible a través de nuevos recursos educativos que la tecnología ofrece, donde se puede indicar que las aulas virtuales, contribuyen a una enseñanza autónoma y mejoran el aprendizaje significativo de los estudiantes, donde a su vez se evidenció que hay ciertas limitaciones en el uso del aula virtual.
La alfabetización informacional: funciones en el desarrollo del pensamiento crítico.
Authors: Rodríguez Mendoza Liccette
Published: December 2021

Las competencias informacionales cada vez son más necesarias para la constitución de un conocimiento propio brindando una lectura crítica a los contenidos disponibles. En este ámbito, la   presente investigación  tiene como objetivo analizar el aporte  de la alfabetización informacional al desarrollo del  pensamiento crítico de los estudiantes de la escuela Nueva Paquisha del cantón Rocafuerte, provincia de Manabí, Ecuador. Se  realizó un estudio empírico con los niños de educación  básica media a quienes se les aplicó una encuesta cuyos resultados demuestran una utilización de técnicas para búsqueda de información,  empleo de la alfabetización informacional  y de sus niveles de preferencia al momento de realizar la búsqueda de datos para algún asunto académico, además se infiere la existencia de habilidades informacionales  para la búsqueda de información en internet, por otro lado se colige un conocimiento y valoración de la alfabetización informacional para potenciar la criticidad en la expresión de ideas por parte de los estudiantes. Se concluye que los educandos por medio de las diversas páginas de consulta  pueden discernir qué tipo de fuentes ofrecen mejores contenidos y cómo emplear esos contenidos en el contexto de sus tareas escolares.
Tareas integradas para mejorar la habilidad de hablar en inglés
Authors: Barrionuevo Villacrés Jeaneth , Vanegas Quishpi Oscar , Otavalo Alvarado Karina
Published: December 2021

Las Tareas Integradas son estrategias de enseñanza-aprendizaje que permiten al docente utilizar diferentes actividades en el aula para mejorar el nivel de inglés de los estudiantes y facilitar la adquisición de nuevos conocimientos, vinculándolos con la interacción social de ntro del aula. Estas actividades impactan en el estudiante y su forma de trabajar ya que las tareas son componentes importantes para desarrollar la competencia comunicativa y facilitar el aprendizaje de una segunda lengua o lengua extranjera. El presente trabajo es de orden cuali-cuantitativo, desarrollado con catorce estudiantes del tercer año de Bachillerato del Colegio Nacional Chordeleg año lectivo 2017 que, a través de la aplicación de las Tareas Integradas significativas e integradas a las cuatro competencias a través de ejercicios, los estudiantes mejoraron sus habilidades del idioma en el hablar, escribir, leer y escuchar, sin embargo, el estudio refleja que los estudiantes mejoraron el nivel de leer más que el de hablar.

Palabras clave: Tareas integradas;investigación pedagógica; metodología; enseñanza de lenguaje
Estado de la pintura de la provincial de Imbabura desde el fin de la colonia hasta inicios del siglo XX: Caso San Antonio de Ibarra
Authors: Gálvez Sánchez Susan Mercedes
Published: December 2021

Durante el periodo colonial se da en el territorio de la Real Audiencia de Quito, un gran desarrollo del arte, ligado al arte religioso. El epicentro de dicha producción artística estuvo centrado en Quito, sin embargo, desde finales del siglo XIX, esta tradición artística se traslada a la localidad de San Antonio de Ibarra, en la provincia de Imbabura (Ecuador), dando paso a un período de florecimiento del arte. El presente artículo se estructura en dos apartados. El primero, hace un acercamiento al estado del arte de la provincia desde el fin de la colonia hasta inicios de este periodo de auge, donde se intenta esclarecer si hubo o no producción artística durante esta etapa. Se toma como referencia las ciudades de Ibarra y Otavalo, principales centros económicos y administrativos de la provincia desde la época colonial. El segundo apartado, estudia la etapa de florecimiento del arte en San Antonio de Ibarra, enfocado sobre todo en el arte de la pintura, que marca a partir de 1884, momento en que se instala la primera escuela de arte y oficios en San Antonio de Ibarra, a cargo de los hermanos Reyes, siendo Luis Reyes, el hermano menor, el encargado de transmitir el arte de la pintura bajo la estética de la Escuela Quiteña, manifestación artística desarrollada durante la época colonial. Esta investigación se apoya principalmente en fuentes primarias: censos de ocupación, certificados de bautismo, libros de actas, inventarios de bienes; además de algunas fuentes secundarias que proporcionan datos parciales que ayudan a reconstruir algunos aspectos del pasado.
Enfoque de género, violencia de género y políticas públicas: un acercamiento desde las Ciencias Sociales al marco jurídico ecuatoriano
Authors: Vera Viteri Leonardo Vicente
Published: December 2021

Se realizó un estudio descriptivo, cuyo objetivo está en caracterizar cuestiones relacionadas con el enfoque de género, violencia de género y políticas públicas desde las Ciencias Sociales y la visión desde el ámbito ecuatoriano. Se empleó el método de análisis documental de contenido en la fundamentación teórica expuesta proveniente de la revisión bibliográfica realizada. Para la contextualización internacional, se consultó revistas de las bases de datos de la Web Of Science y de Scopus que tratan estos temas desde las Ciencias Sociales. Igualmente, para plasmar los referentes nacionales, se realizó búsquedas más específicas sobre el Ecuador en Google Académico. Como resultados se destaca la incidencia de varias leyes, normativas, planes y programas que se han venido elaborando desde la propia Presidencia de la República del Ecuador, así como desde la Asamblea Nacional y de ministerios como el de Educación. Como conclusiones se sugiere el trabajo mancomunado entre todos los sectores sociales y organismos e instituciones gubernamentales para que estas políticas sean implementadas tal como han sido concebidas y se erradique la violencia de género en la sociedad ecuatoriana.
El sentido de una comprensión de textos con sentido. Un estudio de caso.
Authors: Acosta Gómez Israel , Suárez Mena José , Águila Consuegra Maritza , Betancourt Rodríguez Gladys , Rodríguez Álvarez Maidelys
Published: December 2021

La comprensión es un proceso mediante el cual originamos significados al comprender un texto, y en donde el receptor comienza por reconocer las palabras y signos auxiliares, dependiendo del contexto, de las características del texto y la situación comunicativa que se plantee, para luego dotar de sentido, y codificar el conocimiento del mundo, de la ideología, en la reconstrucción de los hechos evocados por el autor-emisor. La presente investigación, aborda una problemática actual dentro de las condiciones de la enseñanza actual; identificada además como un problema de la práctica donde se desempeña el autor de este trabajo. En consecuencia, el objetivo consignado es proponer una estrategia de enseñanza-aprendizaje, que en función del diseño de actividades docentes, se potencie la comprensión del texto poético desde esencias meta cognitivas, reflexivas y estratégicas. Para la consecución de este fin se ejecutó una sistematización de los presupuestos filosóficos, psicológicos, sociológicos y pedagógicos que sustentan el problema; se empleó un sistema de métodos que permitieron un diagnóstico inicial y final, del nivel de desarrollo de habilidades para la comprensión de textos que poseen los estudiantes de Décimo grado. Su aplicación permitió apreciar las dificultades y potencialidades para dar solución al problema detectado.
El empleo del YouTube como herramienta de aprendizaje.
Authors: Posligua Anchundia Rosa
Published: December 2021

Este trabajo se inserta en la línea temática de la utilización  de Youtube  como canal de comunicación educativa y como una herramienta pertinente para el aprendizaje. El objetivo es examinar las potencialidades de YouTube como medio para compartir conocimientos. Se trata de un estudio descriptivo, haciendo uso del método de análisis documental. Se realizó un trabajo empírico  en profesores de bachillerato de la Unidad enmarca en la línea del aprovechamiento de las oportunidades educativas que ofrece este tipo de redes. El proceso Educativa 5 de Junio de la ciudad de Manta, Manabí, Ecuador. Los resultados de esta investigación  evidencian  que los docentes tienen conocimiento de esta herramienta y por tanto  es utilizada  con fines académicos para  apoyar el proceso de enseñanza aprendizaje con los estudiantes. Se concluye que el empleo del Youtube es una oportunidad para la innovación en la educación y un aliado del  proceso formativo y que el profesorado la utiliza de manera frecuente con fines académicos.  El avance de este estudio se de aprendizaje de las diversas disciplinas se facilita con la inclusión de este tipo de recursos.
Fundamentos para potenciar el proceso de aprendizaje del idioma inglés a través de la música
Authors: Almeida Luque Pamela
Published: December 2021

La enseñanza de un nuevo idioma es siempre un reto para los docentes. Particularmente, el inglés exigido en las instituciones de educación presenta una serie de normativas que requiere especial atención por parte de los profesores especializados para motivar a los estudiantes en su proceso de aprendizaje. En este marco, la pedagogía ofrece una serie de estrategias que pueden aplicarse en el plano práctico que permitan incentivar a los alumnos de tal forma que se sientan seducidos por esta disciplina. Algunas de esas estrategias son las que se abordan en el presente trabajo de investigación, especialmente la música. Estas estrategias, que son muy útiles, fomentan habilidades tan esenciales del inglés como son el speaking y el listening; El objetivo de este trabajo fue identificar la influencia de la música en el aprendizaje del idioma inglés.  Esta investigación es de tipo exploratorio, se aplicó una encuesta dirigida a los estudiantes de la Unidad Educativa Sara Belén Guerrero Vargas de Bahía de Caráquez, Manabí, Ecuador. El estudio demuestra que los docentes hacen uso de la música en sus clases y aporta para el aprendizaje del idioma inglés especialmente en las habilidades para el Listening, y Speaking.
Aprendizaje Basado en la Investigación como práctica docente en las aulas Universitarias y su relación con los procesos de titulación de los estudiantes.
Authors: Almeida Monge Elka , Pacheco Mendoza Silvia , Astudillo Cobos Alexandra , Fierro Saltos Raúl
Published: December 2021

El presente trabajo tiene como objetivo fundamental promover que los estudiantes, durante sus años de estudio sean capaces de desarrollar las habilidades y competencias necesarias para investigar, como son: lectura y pensamiento crítico, análisis, síntesis, autodirección, capacidad de trabajar por cuenta propia, liderazgo, innovación, creatividad, utilización adecuada de los recursos disponibles en biblioteca y medios electrónicos entre otras, con la finalidad de involucrarlos en el proceso de descubrimiento científico dentro del trabajo del aula en sus disciplinas específicas, con la finalidad de culminar con excito su trabajo de titulación, la metodología empleada es no experimental, descriptiva y cuantitativa. La muestra empleada fue de 176 docentes de 4 universidades y de 5 facultades, los mismos que son tanto ocasionales como titulares y de diferente grado de formación, los resultados muestran que existe una relación altamente relevante entre el aprendizaje basado en la investigación en el aula y el planteamiento de propuestas exitosas en su proceso de titulación.
La superficialidad en la enseñanza de la trigonometría en el bachillerato y su incidencia en el aprendizaje del cálculo en el nivel universitario.
Authors: Aray Andrade Carlos , Guerrero Alcívar Yandri , Montenegro Palma Luis , Navarrete Ampuero Segundo
Published: December 2021

La trigonometría es una rama importante de las matemáticas. Su riqueza, producto de la estrecha relación con otros dominios matemáticos, las ciencias naturales y la vida cotidiana, abarca varias dimensiones. En este contexto, el propósito de este artículo es presentar los resultados obtenidos de la investigación realizada en la Universidad Técnica de Manabí a alumnos para conocer su percepción sobre las dificultades encontradas en el aprendizaje del cálculo en todos sus niveles (una y varias variables) debido al poco conocimiento de la trigonometría plana y esférica en el nivel secundario. Los resultados muestran que la superficialidad de enseñanza de la trigonometría en la educación secundaria ha provocado un vacío en el conocimiento holístico de la matemática, lo cual dificulta la enseñanza de materias como cálculo de una variable, cálculo de varias variables, ecuaciones diferenciales, álgebra lineal, geometría descriptiva, física, estática y topografía. La destreza para la resolución de identidades trigonométricas desarrolla un coherente razonamiento deductivo y al existir este déficit en el nivel medio este tipo de habilidades y destrezas no adquiridas dificultan la resolución de ejercicios y problemas de cálculo en el ámbito educativo superior.
Information literacy standards for information skills in social work curricula
Authors: Quindemil Torrijo Eneida María , Marzal García-Quismondo Miguel Ángel , Morales Intriago Juan Carlos , Rumbaut León Felipe , Chaparro Martínez Exio Isaac
Published: December 2021

This study proposes information literacy standards to be met by social work curricula. The documentary review used as a point of departure included papers on the introduction of literacy in the curriculum to develop information skills; internationally defined information literacy standards; and the specific and general skills required for social work. The outcome of that review, a proposal for information literacy standards in social work curricula, was assessed by social workers and information scientists. As a result of these two stages of the study, five information literacy standards were defined: one, knowing what type of information is needed; two, accessing the information needed effectively, efficiently and ethically; three, assessing the information and sources, ethically and responsibly building new knowledge with the information selected; four, using and disseminating information effectively and ethically to a specific purpose; and five, keeping abreast of and networking with the information. Implementing those standards helps develop information skills while working toward a degree in social work. Coupled with other specific and general professional aptitudes, such skills help graduates address the issues with which they are confronted in social research and intervention.
Código de ética del profesional bibliotecario caso: Biblioteca Central de la UTM
Authors: Soledispa Fernández Randy , Zambrano Cedeño Edison
Published: December 2021

El presente trabajo de investigación hace referencia a la ética del profesional bibliotecario, a través de la existencia de un código deontológico en las bibliotecas universitarias como lo es la Biblioteca Central Dr. Alejandro Muñoz Dávila de la Universidad Técnica de Manabí. El objetivo de este trabajo fue investigar la existencia de un código de ética del profesional bibliotecario: caso Biblioteca Central de la UTM. Además proponer a la comunidad bibliotecaria un análisis teórico del tema, para así poder  emprender la tarea de fundamentar una ética bibliotecaria, definir el papel ético de las bibliotecas en la sociedad contemporánea y su compromiso social, ante lo cual vemos la necesidad de que al conocimiento teórico de la Bibliotecología se le sumen unos principios éticos básicos en relación con esa responsabilidad social del bibliotecario, encaminadas a mejorar su desempeño profesional y su contribución a la sociedad además se pretende promover una ética bibliotecaria para el ejercicio de la profesión y será un aporte al conformar un código deontológico aplicado a la bibliotecología especialmente a la Biblioteca Central Dr. Alejandro Muñoz Dávila de la UTM. Además, con la aplicación de las técnicas de la encuesta dirigida al personal que labora en la biblioteca de la UTM y la entrevista dirigida a los profesionales especializados en el área de la Bibliotecología se determinara los criterios y sugerencias sobre el código de ética que debe poseer el bibliotecario.
Incidencia de los juegos individuales y colectivos en las habilidades y destrezas de los estudiantes
Authors: Cedeño Zambrano Efrén , Calle García Robertson
Published: December 2021

Las actividades lúdicas constituyen un poderoso aliado para los docentes en el ámbito formativo. Los juegos, particularmente, contribuyen de forma significativa al desarrollo de habilidades y destrezas de los estudiantes tanto físicas como cognitivas debido a que dinamizan el proceso de enseñanza y aprendizaje. En este contexto, la presente investigación que se propone a continuación pretende determinar y analizar la incidencia que los juegos, tanto individuales como colectivos, en el desarrollo de las capacidades de los estudiantes. Para ello se ha focalizado el estudio en la sección básica superior de la Unidad Educativa Pedro Zambrano Barcia de Portoviejo. Adicional a ello se busca identificar las estrategias didácticas empleadas por los profesores que motivan el proceso de enseñanza en el aula de clases, así como los procedimientos y tipos de juegos que tengan más relevancia para los alumnos en estos niveles de estudio. Por ello se realizará un abordaje metodológico mixto, tanto cualitativo como cuantitativo, y se elaborará un trabajo empírico para concretar los objetivos plasmados. Se pretende que la investigación sea un aporte en cuando a la construcción de nuevos conocimientos en los que se emplee la innovación y el carácter lúdico de determinadas temáticas propuestas en clases.