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(Ril editores, 2016) Del Barrio Vásquez, Diego
Taxanes for advanced non-small cell lung cancer (Protocol)
(Cochrane, 2018) Madrid, Eva; Barros Monge, Manuel J; Urrútia, Gerard; Roqué I Figuls, Marta; Pérez Bracchiglione, Javier; Vargas Peirano, Manuel; Loézar Hernández, Cristóbal Nicolás; Bonfill Cosp, Xavier
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To assess the effects of taxanes as part of a combined or single‐agent therapy versus other agents or best supportive care as first‐ or second‐line treatment for advanced non‐small cell lung cancer (NSCLC). A secondary objective is to assess different modes or schemes of administration of taxanes in patients with this disease.
Pre‐ and postnatal alcohol exposure delays, in female but not in male rats, the extinction of an auditory fear conditioned memory and increases alcohol consumption
(Wiley, 2019) Plaza, Wladimir; Gaschino, Felice; Gutiérrez, Camilo; Santibañez, Nicolás; Estay‐Olmos, Camila; Sotomayor‐Zárate, Ramón; De la Fuente‐Ortega, Erwin; Pautass, Ricardo M.; Haeger, Paola A.
Repeated exposure to alcohol increases retrieval of fear‐conditioned memories, which facilitates, among other factors, the emergence of post‐traumatic stress disorder (PTSD). Individuals with PTSD are more likely to develop alcohol and substance abuse related disorders. We assessed if prenatal and early postnatal alcohol exposure (PAE) increased the susceptibility to retain aversive memories and if this was associated with subsequent heightened alcohol consumption. Pregnant Sprague‐Dawley rats were exposed for 22 hr/day, throughout pregnancy and until postnatal Day 7 to a single bottle of sucralose ‐ sweetened 10% alcohol solution (PAE Group), or to a single bottle of tap water and sucralose (Control Group). Auditory fear conditioning (AFC) was performed in the adolescent offspring at postnatal Day 40. Freezing was measured during acquisition, retention and extinction phases, followed by 3 weeks of free choice alcohol intake. Female, but not male, PAE rats exhibited impaired extinction of the aversive memory, a finding associated with higher levels of 3‐4 Dihidroxyphenylacetic acid (DOPAC) in the nucleus accumbens and heightened alcohol intake, respect to controls. These findings suggest that PAE makes females more vulnerable to long‐term retention of aversive memories, which coexist with heightened alcohol intake. These findings are reminiscent of those of PTSD
Development of Fixed Dose Combination Products Workshop Report: Considerations of Gastrointestinal Physiology and Overall Development Strategy
(Springer, 2019) Hens, Bart; Corsetti, Maura; Bermejo, Marival; Löbenberg, Raimar; González, Pablo M.; Mitra, V; Desai, Divyakant; Murthy Chilukuri, Dakshina; Aceituno, Alexis
The gastrointestinal (GI) tract is one of the most popular and used routes of drug product administration due to the convenience for better patient compliance and reduced costs to the patient compared to other routes. However, its complex nature poses a great challenge for formulation scientists when developing more complex dosage forms such as those combining two or more drugs. Fixed dose combination (FDC) products are two or more single active ingredients combined in a single dosage form. This formulation strategy represents a novel formulation which is as safe and effective compared to every mono-product separately. A complex drug product, to be dosed through a complex route, requires judicious considerations for formulation development. Additionally, it represents a challenge from a regulatory perspective at the time of demonstrating bioequivalence (BE) for generic versions of such drug products. This report gives the reader a summary of a 2-day short course that took place on the third and fourth of November at the Annual Association of Pharmaceutical Scientists (AAPS) meeting in 2018 at Washington, D.C. This manuscript will offer a comprehensive view of the most influential aspects of the GI physiology on the absorption of drugs and current techniques to help understand the fate of orally ingested drug products in the complex environment represented by the GI tract. Through case studies on FDC product development and regulatory issues, this manuscript will provide a great opportunity for readers to explore avenues for successfully developing FDC products and their generic versions.
Inclusión de salud basada en evidencia en carreras de la salud en Chile y el modelo integrado Metodología de la Investigación Científica-Medicina Basada en Evidencia en la Universidad de Valparaíso
(Elsevier, 2019) Papuzinski, Cristian; Loézar, Cristóbal; Carvajal, Natalia; Vargas, Manuel; Borgeat, Marjorie; Madrid, Eva; Pérez-Bracchiglione, Javier; Arancibia, Marcelo
Introducción: La salud basada en evidencia (SBE) integra el uso de la mejor evidencia, la experiencia clínica y los valores y preferencias del paciente para la toma de decisiones. Su incorporación en las carreras sanitarias de Chile es desconocida. Métodos: Se realizó un estudio de corte transversal para evaluar la incorporación de SBE en los programas de las carreras sanitarias en Chile hasta 2019. Se describe la integración del modelo Metodología de la Investigación Científica (MIC)-Medicina Basada en la Evidencia (MBE) en la Escuela de Medicina de la Universidad de Valparaíso. Resultados: Un total de 49 universidades imparten carreras sanitarias. Un 8,13% incorpora SBE como asignatura explícitamente. Todas incorporan asignaturas que potencialmente incluyen contenidos de SBE. Las carreras de Medicina y Enfermería son las que más incorporan SBE, pero solo una carrera de Medicina incluye SBE como asignatura por más de un semestre. El modelo integrado MIC/MBE (4 semestres), orientado en competencias y centrado en el alumno, involucra el diseno ̃ y ejecución de un protocolo de investigación, así como el análisis crítico de la mejor evidencia, integrado con los valores de los pacientes. Conclusión: La incorporación de SBE como asignatura es muy infrecuente en carreras sanitarias chilenas. Se enfatiza su inclusión transdisciplinaria como asignatura individual desde un modelo que integre la ensenanza ̃ de MIC, sobre todo en universidades estatales.
¿Qué tecnología escojo para mi clase? Percepción de estudiantes de medicina sobre clickers y Kahoot
(Fundación Educación Médica, 2020) Guerra Zuñiga, Maria; Cuevas Lang, Katherine; Segovia Chamorro, Jaime
Introducción: Las nuevas generaciones de estudiantes y las distintas problemáticas de las asignaturas instan a modificar las actividades formativas hacia nuevas formas utilizando tecnologías de la información y la comunicación. Objetivo: Identificar la opinión de los alumnos de primer y segundo año de la carrera de medicina, Universidad de Valparaíso, respecto del uso de un sistema inalámbrico de respuesta (clicker) y Kahoot en el aula. Sujetos y métodos: Estudio cualitativo, fenomenológico. Para la producción de información se realizaron 2 grupos focales con un total de 18 participantes, los cuales se transcribieron según el principio de verbatim. El análisis utilizado fue de contenido. Se efectuó triangulación de la información con técnica de investigadores. Resultados: El uso de clickersy Kahoot se ha valorado positivamente. Se produjo información acerca de las ventajas e inconvenientes de cada una de las tecnologías. Ambas logran focalizar la atención de los estudiantes y aumentan su sensación de disfrute, aprendizaje y calidad de vida al ser estrategias de gamificación. Conclusión: Ambas estrategias tienen la potencialidad de modificar favorablemente los ambientes del aula, con ventajas y limitaciones que deben ser conocidas por los docentes. Es relevante insertarlas dentro de estrategias educativas coherentes para potenciar los procesos de enseñanza-aprendizaje.
Cataclysmic variable evolution and the white dwarf mass problem: A Review
(Elsevier, 2020) Zorotovic, Mónica; Schreiber, Matthias R.
Although the theory of cataclysmic variable (CV) evolution is able to explain several observational aspects, strong discrepancies have existed for decades between observations and theoretical predictions of the orbital period distribution, the location of the minimum period, and the space density of CVs. Moreover, it has been shown in the last decade that the average white dwarf (WD) mass observed in CVs is significantly higher than the average mass in single WDs or in detached progenitors of CVs, and that there is an absence of helium-core WDs in CVs which is not observed in their immediate detached progenitors. This highly motivated us to revise the theory of CV formation and evolution. A new empirical model for angular momentum loss in CVs was developed in order to explain the high average WD mass observed and the absence of systems with helium-core WDs. This model seems to help, at the same time, with all of the above mentioned disagreements between theory and observations. Moreover, it also provides us with a very likely explanation for the existence of low-mass WDs without a companion. Here we will review the standard model for CV evolution and the disagreements that have existed for decades between simulations and observations with their possible solutions and/or improvements. We will also summarize the recently confirmed disagreement related to the average WD mass and the fraction of helium-core WDs among CVs, as well as the development of an empirical model that allows us to solve all the disagreements, discussing the physics that could be involved.
Efecto de la ingesta de los edulcorantes estevia y D-tagatosa sobre glicemia, péptido C y apetito-saciedad en mujeres con resistencia a la insulina
(Sociedad Chilena De Endocrinología Y Diabetes, 2020) Sambra Vásquez, Verónica; Vega Soto, Claudia; Vicuña Herrera, Isabella; Priken Figueroa, Kathleen; Novik Assael, Victoria; Allendes González, Daniela; Godoy Vega, Paula; Luna Selva, Leticia
Objetivos: Comparar los efectos de la ingesta de una precarga de edulcorantes no nutritivos (ENN) estevia y D-tagatosa, previo a una carga de glucosa oral, sobre la glicemia, péptido C y apetito objetivo y subjetivo en mujeres con resistencia a la insulina (RI). Diseño Experimental: Se usó un diseño de tratamiento cruzado donde cada voluntaria fue su propio control, doble ciego. La 1° prueba correspondió a administración de agua, la 2° y 3° prueba a la administración aleatoria de ENN. En cada prueba, se instaló un catéter intravenoso en la vena antecubital y se tomó muestra de sangre basal. Inmediatamente, bebió 60 ml de agua solo o con 5 g de D-tagatosa o 15.3 mg de estevia. Después de 10 minutos, la voluntaria recibió una carga de glucosa oral, 75 g en la prueba con D-tagatosa y 77.1 g en la prueba con agua o estevia (2.1 g más de glucosa para compensar el aporte calórico de D-tagatosa, 1.5 kcal/g), y se tomó la muestra de sangre “tiempo 0”. Posteriormente, extracciones de sangre a los 30, 60, 90, 120 y 180 minutos. Se evaluó el apetito al término de la prueba. Sujetos y métodos: 33 mujeres (IMC 28.1 ± 3.4 kg/m2, edad 23.4 ± 3.8 años) con RI según HOMA-IR. La glicemia se midió usando un método GOD-PAP, y el Péptido-C, un inmunoensayo enzimático colorimétrico ELISA. Se realizó una evaluación objetiva de apetito, a través del consumo de un buffet. Además, se aplicó una Escala Visual Análoga (EVA) conformada por 8 preguntas para la evaluación subjetiva de apetito. Resultados: En el tiempo 30, la glicemia de los tratamientos control (p=0.004) y estevia (p=0.02) fueron más altas que el tratamiento tagatosa. En el tiempo 90 la concentración de péptido-C fue significativamente más alta en el tratamiento con estevia v/s el control (p=0.035) y en el tiempo 120 estevia presentó un valor significativamente más alto de péptido C al compararlo con tagatosa (p=0.039). El área bajo la curva (ABC) (p=0.005) y ABCincremental (p=0.009) de péptido C fue significativamente mayor tras la ingesta de estevia al comparar con tagatosa y agua (control). Hubo mayor sensación de hambre a los 30 minutos de haber ingerido estevia al compararlo con tagatosa (p=0.014) y agua (p<0.001) y a los 60 minutos post ingesta de estevia (p<0.001) y tagatosa (p=0.02) respecto al control. Mayor reporte de sensación de saciedad una hora después de la ingesta de estevia (p<0.001) y tagatosa (p<0.001) al comparar con agua. Además, mayor “deseo de ingerir un alimento” a los 90 (p=0.00) y 120 (p=0.00) minutos después de haber ingerido estevia sólo al comparar con agua. Conclusión: La tagatosa podría ser beneficiosa para la salud metabólica de una mujer con RI; la estevia, podría promover un efecto insulinotrópico no beneficioso en estas mujeres. A los 60 minutos con ambos ENN hubo más saciedad, pero la estevia a los 120 minutos generó mayor deseo de ingerir alimentos, que no se vio reflejado en el apetito objetivo, puesto que no hubo diferencias en la ingesta de alimentos del buffet ad libitum. Financiamiento: Sociedad Chilena de Endocrinología y Diabetes, proyecto SOCHED 17-10
Pharmacological Characterization of 4- Methylthioamphetamine Derivatives
(MDPI, 2020) Guajardo, Fabrizzio G.; Velásquez, Victoria B.; Raby, Daniela; Núñez-Vivanco, Gabriel; Iturriaga-Vásquez, Patricio; España, Rodrigo A.; Miguel, Reyes-Parada; Sotomayor-Zárate, Ramón
Amphetamine derivatives have been used in a wide variety of pathologies because of their pharmacological properties as psychostimulants, entactogens, anorectics, and antidepressants. However, adverse cardiovascular effects (sympathomimetics) and substance abuse problems (psychotropic and hallucinogenic effects) have limited their use. 4-Methylthioamphetamine (MTA) is an amphetamine derivative that has shown to inhibit monoamine uptake and monoamine oxidase. However, the pharmacological characterization (neurochemical, behavioral, and safety) of its derivatives 4-ethylthioamphetamine (ETA) and 4-methylthio-phenil-2-butanamine (MT-But) have not been studied. In the current experiments, we show that ETA and MT-But do not increase locomotor activity and conditioned place preference with respect to MTA. At the neurochemical level, ETA and MT-But do not increase in vivo DA release in striatum, but ETA and MT-But affect the nucleus accumbens bioaccumulation of DA and DOPAC. Regarding cardiovascular effects, the administration of MTA and ETA increased the mean arterial pressure and only ETA significantly increases the heart rate. Our results show that the pharmacological and safety profiles of MTA are modulated by changing the methyl-thio group or the methyl group of the aminoethyl chain.
Dust trapping around Lagrangian points in protoplanetary disks
(European Southern Observatory, 2020) Montesinos, Matías; Olofsson, Johan; Bayo, Amelia; Sucerquia, Mario
Aims. Trojans are defined as objects that share the orbit of a planet at the stable Lagrangian points L4 and L5. In the Solar System, these bodies show a broad size distribution ranging from micrometer (μm) to centimeter (cm) particles (Trojan dust) and up to kilometer (km) rocks (Trojan asteroids). It has also been theorized that earth-like Trojans may be formed in extra-solar systems. The Trojan formation mechanism is still under debate, especially theories involving the effects of dissipative forces from a viscous gaseous environment. Methods. We perform hydro-simulations to follow the evolution of a protoplanetary disk with an embedded 1–10 Jupiter-mass planet. On top of the gaseous disk, we set a distribution of μm–cm dust particles interacting with the gas. This allows us to follow dust dynamics as solids get trapped around the Lagrangian points of the planet. Results. We show that large vortices generated at the Lagrangian points are responsible for dust accumulation, where the leading Lagrangian point L4 traps a larger amount of submillimeter (submm) particles than the trailing L5, which traps mostly mm–cm particles. However, the total bulk mass, with typical values of ~Mmoon, is more significant in L5 than in L4, in contrast to what is observed in the current Solar System a few gigayears later. Furthermore, the migration of the planet does not seem to affect the reported asymmetry between L4 and L5. Conclusions. The main initial mass reservoir for Trojan dust lies in the same co-orbital path of the planet, while dust migrating from the outer region (due to drag) contributes very little to its final mass, imposing strong mass constraints for the in situ formation scenario of Trojan planets.
Braquiterapia adaptativa guiada por resonancia magnética para el cáncer cervical localmente avanzado: Experiencia del Hospital Carlos Van Buren
(Sociedad Chilena de Obstetricia y Ginecología, 2020) Solis, JA; Olivares, J; Tudela, B; Veillon, G; Perrot, I; Lazcano, G
Introducción y objetivos: El tratamiento estándar para pacientes con cáncer cervical localmente avanzado (CCLA) se basa en radioterapia externa y quimioterapia concomitante seguida de braquiterapia adaptativa guiada por imágenes (BTAGI). El objetivo de este estudio fue describir los resultados del protocolo de BTAGI de resonancia magnética del Servicio de Oncología del Hospital Carlos Van Buren. Métodos: En pacientes con CCLA tratadas con Radioquimioterapia concomitante seguida de BTAGI de resonancia magnética se evaluó la reducción tumoral, parámetros dosimétricos y la toxicidad aguda. Resultados: Se evaluó la reducción tumoral entre el diagnóstico y el momento de la braquiterapia en 34 pacientes. Todas las pacientes completaron el tratamiento de radioterapia externa. Veinticuatro pacientes recibieron 3 sesiones de braquiterapia. Dosis equivalentes totales > 80 Gy se logro en todos los pacientes. Doce pacientes presentaron reducción del volumen tumoral mayor al 70%. La mediana de las dosis equivalentes totales prescritas al D2cc de vejiga fue 73.9 Gy, al recto 65.6 Gy y al intestino fue de 69.1 Gy. Una paciente presento toxicidad gastrointestinal grado ≥ 3. No hubo diferencias estadísticamente significativas al comparar pacientes que recibieron dosis equivalentes totales desde los 85 Gy con las que recibieron menor dosis respecto a toxicidad gastrointestinal (p=0.33) y genitourinaria (p=0.97). Conclusión: La braquiterapia adaptativa guiada por resonancia magnética se puede realizar en el sistema público de salud y cumplir con las recomendaciones internacionales requeridas para el tratamiento estándar del CCLA.
Managing slow-moving item: a zero- inflated truncated normal approach for modeling demand
(PeerJ Publishing, 2020) Rojas, Fernando; Wanke, Peter; Coluccio, Giuliani; Vega-Vargas, Juan; Huerta-Canepa, Gonzalo F.
This paper proposes a slow-moving management method for a system using of intermittent demand per unit time and lead time demand of items in service enterprise inventory models. Our method uses zero-inflated truncated normal statistical distribution, which makes it possible to model intermittent demand per unit time using mixed statistical distribution. We conducted numerical experiments based on an algorithm used to forecast intermittent demand over fixed lead time to show that our proposed distributions improved the performance of the continuous review inventory model with shortages.Weevaluated multi-criteria elements (total cost, fill-rate, shortage of quantity per cycle, and the adequacy of the statistical distribution of the lead time demand) for decision analysis using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). We confirmed that our method improved the performance of the inventory model in comparison to other commonly used approaches such as simple exponential smoothing and Croston's method. We found an interesting association between the intermittency of demand per unit of time, the square root of this same parameter and reorder point decisions, that could be explained using classical multiple linear regression model. We confirmed that the parameter of variability of the zeroinflated truncated normal statistical distribution used to model intermittent demand was positively related to the decision of reorder points. Our study examined a decision analysis using illustrative example. Our suggested approach is original, valuable, and, in the case of slow-moving item management for service companies, allows for the verification of decision-making using multiple criteria.
The ALPINE-ALMA [CII] survey: Survey strategy, observations, and sample properties of 118 star-forming galaxies at 4
(European Southern Observatory, 2020) Ibar, Eduardo; Mendez Hernandez, Hugo
The ALMA-ALPINE [CII] survey is aimed at characterizing the properties of a sample of normal star-forming galaxies (SFGs). The ALMA Large Program to INvestigate (ALPINE) features 118 galaxies observed in the [CII]-158μm line and far infrared (FIR) continuum emission during the period of rapid mass assembly, right after the end of the HI reionization, at redshifts of 45). Based on a visual inspection of the [CII] data cubes together with the large wealth of ancillary data, we find a surprisingly wide range of galaxy types, including 40% that are mergers, 20% extended and dispersion-dominated, 13% compact, and 11% rotating discs, with the remaining 16% too faint to be classified. This diversity indicates that a wide array of physical processes must be at work at this epoch, first and foremost, those of galaxy mergers. This paper sets a reference sample for the gas distribution in normal SFGs at 4
Involvement of NO in Antinociception of NSAIDS in Murine Formalin Hind Paw Assay
(Thieme, 2020) Noriega, Viviana; Miranda, Hugo F.; Prieto, Juan Carlos; Sotomayor-Zárate, Ramón; Sierralta, Fernando
There are different animal models to evaluate pain among them the formalin hind paw assay which is widely used since some of its events appear to be similar to the clinical pain of humans. The assay in which a dilute solution of formalin is injected into the dorsal hindpaw of a murine produces two ‘phases’ of pain behavior separated by a inactive period. The early phase (Phase I) is probably due to direct activation of nociceptors and the second phase (Phase II) is due to ongoing inflammatory input and central sensitization. Mice were used to determine the potency antinociceptive of piroxicam (1,3,10,and 30 mg/kg), parecoxib (0.3, 1,3,10 and 30 mg/kg), dexketoprofen (3,10,30 and 100 mg/kg) and ketoprofen (3,10,30 and 100 mg/kg). Doseresponse for each NSAIDs were created before and after 5 mg/kg of LNAME i.p. or 5 mg/kg i.p. of 7nitroindazole. A leastsquares linear regression analysis of the log dose–response curves allowed the calculation of the dose that produced 50 % of antinociception (ED50) for each drug. The ED50 demonstrated the following rank order of potency, in the phase I: piroxicam > dexketoprofen > ketoprofen > parecoxib and in the phase II: piroxicam > ketoprofen > parecoxib > dexketoprofen. Pretreatment of the mice with LNAME or 7nitroindazol induced a significant increase of the analgesic power of the NSAIDs, with a significant reduction of the ED50. It is suggested that NO may be involved in both phases of the trial, which means that nitric oxide regulates the bioactivity of NSAIDs.
Polis en conflicto: memoria urbana del Golpe de Estado de septiembre de 1973 en Valparaíso, Chile
(Centro de Investigaciones Geográficas, 2020) Castañeda Meneses, Patricia; Cazorla Becerra, Ketty; Cuevas Lang, Katherine
En Chile, el 11 de septiembre de 1973 se produce un Golpe de Estado que inicia una dictadura cívico militar que se extendió hasta marzo de 1990. El presente trabajo tiene por objetivo rescatar la memoria urbana de la población mayor de Valparaíso respecto del desarrollo del Golpe de Estado en la ciudad. Se realizó un trabajo de campo aplicando 32 entrevistas cualitativas de enfoque biográfico. Los resultados indican que la memoria de la ciudad reconoce en el Golpe de Estado un hito que fracturó la polis a través de la ruptura del espacio político ciudadano debido a la intervención militar. Como consecuencia, las relaciones entre el Estado y la ciudadanía quedaron retenidas dentro de un marco dictatorial de 17 años, aportando un complejo legado de confrontación urbana definida desde el conflicto y la hostilidad.
Screening de Lesiones Orales Malignas y Potencialmente Malignas en Funcionarios de Universidad de Valparaíso y Universidad Viña del Mar Durante los Años 2016 - 2017
(Universidad de La Frontera, 2020) Cordero, Karina; Torres, Coral; Anabalón, Paula; Fernández, María José; Suzarte, Josefina; Wu, Kai
El objetivo de este estudio es determinar la prevalencia de lesiones orales malignas y potencialmente malignas (LPM) en funcionarios de la Universidad de Valparaíso y de Viña del Mar durante los años 2016 - 2017. Fueron citados 161 funcionarios, quienes accedieron a una encuesta que evaluaba factores de riesgo de cáncer oral (tabaco y alcohol) y si habían escuchado de la patología, sumado a un examen clínico. De los pacientes examinados, se diagnosticaron 121 lesiones de las cuales 2 fueron diagnosticadas como lesiones potencialmente malignas: Liquen plano y Leucoplasia, con una prevalencia de 1,7 %. El 50,3 % de los pacientes sabía de la existencia de cáncer oral. El Screening es una medida que permite dar a conocer a la población la existencia de cáncer oral y alertarlos sobre la importancia de su examen para su identificación de manera temprana.
The Gaia-ESO survey: 3D NLTE abundances in the open cluster NGC 2420 suggest atomic diffusion and turbulent mixing are at the origin of chemical abundance variations
(European Southern Observatory, 2020)
Context. Atomic diffusion and mixing processes in stellar interiors influence the structure and the surface composition of stars. Some of these processes cannot yet be modelled from the first principles, and they require calibrations. This limits their applicability in stellar models used for studies of stellar populations and Galactic evolution. Aims. Our main goal is to put constraints on the stellar structure and evolution models using new refined measurements of the chemical composition in stars of a Galactic open cluster. Methods. We used medium-resolution, 19 200 ≤ R ≤ 21 500, optical spectra of stars in the open cluster NGC 2420 obtained within the Gaia-ESO survey. The sample covers all evolutionary stages from the main sequence to the red giant branch. Stellar parameters were derived using a combined Bayesian analysis of spectra, 2MASS photometry, and astrometric data from Gaia DR2. The abundances of Mg, Ca, Fe, and Li were determined from non-local thermodynamic equilibrium (NLTE) synthetic spectra, which were computed using one-dimensional (1D) and averaged three-dimensional (3D) model atmospheres. We compare our results with a grid of Code d’Evolution Stellaire Adaptatif et Modulaire (CESTAM) stellar evolution models, which include atomic diffusion, turbulent, and rotational mixing. Results. We find prominent evolutionary trends in the abundances of Fe, Ca, Mg, and Li with the mass of the stars in the cluster. Furthermore, Fe, Mg, and Ca show a depletion at the cluster turn-off, but the abundances gradually increase and flatten near the base of the red giant branch. The abundance trend for Li displays a signature of rotational mixing on the main sequence and abrupt depletion on the sub-giant branch, which is caused by advection of Li-poor material to the surface. The analysis of abundances combined with the CESTAM model predictions allows us to place limits on the parameter space of the models and to constrain the zone in the stellar interior, where turbulent mixing takes place.
The lithium-rotation connection in the newly discovered young stellar stream Psc-Eri (Meingast 1)
(European Southern Observatory, 2020) Bayo, Amelia; Arancibia Silva
Context. As a fragile element, lithium is a sensitive probe of physical processes occurring in stellar interiors. Aims. We aim to investigate the relationship between lithium abundance and rotation rate in low-mass members of the newly discovered 125 Myr-old Psc–Eri stellar stream. Methods. We obtained high-resolution optical spectra and measured the equivalent width of the 607.8 nm LiI line for 40 members of the Psc–Eri stream, whose rotational periods have been previously derived. Results. We show that a tight correlation exists between the lithium content and rotation rate among the late-G to early-K-type stars of the Psc–Eri stream. Fast rotators are systematically Li rich, while slow rotators are Li depleted. This trend mimics that previously reported for the similar age Pleiades cluster. Conclusions. The lithium-rotation connection thus seems to be universal over a restricted effective temperature range for low-mass stars at or close to the zero-age main sequence, and does not depend on environmental conditions.
TDCOSMO
(European Southern Observatory, 2020) Motta, Verónica
Time-delay cosmography of lensed quasars has achieved 2.4% precision on the measurement of the Hubble constant, H0. As part of an ongoing effort to uncover and control systematic uncertainties, we investigate three potential sources: 1- stellar kinematics, 2- line-of-sight effects, and 3- the deflector mass model. To meet this goal in a quantitative way, we reproduced the H0LiCOW/SHARP/STRIDES (hereafter TDCOSMO) procedures on a set of real and simulated data, and we find the following. First, stellar kinematics cannot be a dominant source of error or bias since we find that a systematic change of 10% of measured velocity dispersion leads to only a 0.7% shift on H0 from the seven lenses analyzed by TDCOSMO. Second, we find no bias to arise from incorrect estimation of the line-of-sight effects. Third, we show that elliptical composite (stars + dark matter halo), power-law, and cored power-law mass profiles have the flexibility to yield a broad range in H0 values. However, the TDCOSMO procedures that model the data with both composite and power-law mass profiles are informative. If the models agree, as we observe in real systems owing to the “bulge-halo” conspiracy, H0 is recovered precisely and accurately by both models. If the two models disagree, as in the case of some pathological models illustrated here, the TDCOSMO procedure either discriminates between them through the goodness of fit, or it accounts for the discrepancy in the final error bars provided by the analysis. This conclusion is consistent with a reanalysis of six of the TDCOSMO (real) lenses: the composite model yields H0 = 74.0−1.8+1.7 km s−1 Mpc−1, while the power-law model yields 74.2−1.6+1.6 km s−1 Mpc−1. In conclusion, we find no evidence of bias or errors larger than the current statistical uncertainties reported by TDCOSMO.
Lo educativo en tiempos trans-modernos: aportes para la construcción de un pensamiento educativo situado
(Universidad del Zulia, 2020) Toro Arévalo, Sergio; Peña Troncoso, Sebastián; Vega Ramírez, Javier; Moreno Doña, Alberto
El presente trabajo aborda dos aspectos fundamentales en el contexto del pensamiento educativo contemporáneo. Por una parte, se adentra en caracterizar lo educativo desde el contexto latinoamericano social, teórico e histórico, describiendo los componentes configurativos de dicho proceso a partir de Freire, Maturana, Dussel e Ilich y, por otra parte, desarrollar una síntesis de las propuestas de frontera de las ciencias de la cognición a través de una base comprensiva y activa de orientación educativa situada en el contexto de la ecología de saberes y el mosaico cultural singular de América del Sur. La base metodológica es fundamentalmente hermenéutica y epistemológica-política. El resultado es un aporte a la discusión educativa revelando, desde lo situado, los procesos de transformación educativa, tanto a nivel personal como comunitario.

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