Teachers as researchers: Reflecting on the challenges of research–practice partnerships between school and university in Chile

Teachers have tended to be underestimated as experts of their own practice and relegated to a technical role. In this context, action research appears as a form to legitimate teachers as active agents and producers of educational knowledge. This article aims to examine how a collaborative research–practice partnership between schools and universities in Chile fosters teachers’ role as researchers. It adopts a qualitative methodology based on thematic analysis of data collected from questionnaires and focus groups. In particular, it reports perceptions of inservice teacher researchers who conducted research projects between 2016 and 2017 as a part of a researcher–practitioner partnership strategy implemented by a university in Chile. The findings suggest that the partnerships were highly valued among teachers because the partnerships allowed them to develop pedagogical reflection towards the improvement of their practices and required particular awareness and recognition of roles and the relationships between practical and theoretical knowledge. Finally, possibilities for strengthening teachers’ role as researchers and collaborative research are presented at the end of the article

Optical properties of polycrystalline Cd(1-x)Mn(x)Te

Bulk polycrystalline cadmium manganese telluride, Cd(l-x)Mn(x)Te, was manufactured in several compositions by a synthesis process. The structure of the obtained compounds was the characteristic zinc-blende polycrystalline pattern being the grain size lOOj=20 nm. These materials are manufactured to replace single-crystal compounds in some magneto-optical devices. The cut-off wavelength and the Verdet constant are the same as the single-crystals with identical composition. A polarized laser beam, after having passed through a sample of 0.76 mm thickness, was depolarized less than 2.5%, and 90% of its energy was spread into a 2º cone. Scattering of light is produced because of the polycrystalline structure of these ompounds. Some scattering diagrams, due to the diffraction and Mie scattering in the polycrystalline grains are shown

Incidence of complications in breast reconstruction with autologous tissue in a third level hospital

Background: The objective of this study is to analyze the incidence of complications after breast reconstruction with pedicled or free flaps at the hospital general de Mexico "Dr. Eduardo Liceaga”. Methods: A retrospective, single-center study, including 44 female patients, who underwent immediate or delayed breast reconstruction after breast cancer, between 2019 and 2020, and had at least a 2-year follow up, evaluating the association between patient risk factors (age, history of radiotherapy, presence of overweight or obesity and immediate or delayed reconstruction) with the presence of complications such as seroma, hematoma, wound infection or wound dehiscence. We analyzed data with SPSS software, v23.0. Results: There was no statistically significant difference for the presence of complications associated with risk factors studied. Conclusions: We need more prospective, multicenter studies, including larger sample and strict follow up of patients

Estimating the urban atmospheric boundary layer height from remote sensing applying machine learning techniques

This work was supported by the Spanish Ministry of Economy and Competitiveness through projects CGL2015- 73250-JIN, CGL2016-81092-R, CGL2017-83538-C3-1-R ,CGL2017-90884-REDT and PID2020-120015RB-I00 and by the University of Granada through “Plan Propio. Programa 9 Convocatoria 2013. The financial support for EARLINET in the ACTRIS Research Infrastructure Project by the European Union’s Horizon 2020 research and innovation program through project ACTRIS-2 (grant agreement No 654109). The authors thankfully acknowledge the FEDER program for the instrumentation used in this work and the University of Granada that supported this study through the Excellence Units Program. COST Action TOPROF (ES1303), supported by497 COST (European Cooperation in Science and Technology), is also acknowledged.This study proposes a new methodology to estimate the Atmospheric Boundary Layer Height (ABLH), discriminating between Convective Boundary Layer and Stable Boundary Layer heights, based on the machine learning algorithm known as Gradient Boosting Regression Tree. The algorithm proposed here uses a first estimation of the ABLH derived applying the gradient method to a ceilometer signal and several meteorological variables to obtain ABLH values comparable to those derived from a microwave radiometer. A deep analysis of the model configuration and its inputs has been performed in order to avoid the model overfitting and ensure its applicability. The hourly and seasonal values and variability of the ABLH values obtained with the new algorithm have been analyzed and compared with the initial estimations obtained using only the ceilometer signal. Mean Relative Errors (MRE) between the ABLH estimated with the new algorithm and microwave radiometer show a daily pattern with their highest values during the night-time (stable situations) and their lowest values along the day-time (convective situations). This pattern has been observed for all the seasons with MRE ranging between −5% and 35%. This result notably improves those ABLH values derived by applying the gradient method to ceilometer data during convective situations and enables the Stable Boundary Layer height detection at night and early morning, instead of only Residual Layer top height. Finally, the model performance has been directly validated in three particular cases: clear-sky day, presence of low-clouds and dust outbreak event. In these three particular situations, ABLH values obtained with the new algorithm follow the pattern obtained with the microwave radiometer presenting very similar values, thus confirming the good model performance. In this way it is feasible by the combination of the proposed method with gradient method, to estimate Convective, Stable and Residual Boundary Layer height from ceilometer data and surface meteorological data in extended network that include ceilometer profiling.Spanish Ministry of Economy and Competitiveness through projects CGL2015-73250-JIN, CGL2016-81092-R, CGL2017-83538-C3-1-R, CGL2017-90884-REDT and PID2020-120015RB-I00COST Action TOPROF (ES1303), supported by COST (European Cooperation in Science and Technology

Unveiling the stellar origin of the Wolf-Rayet nebula NGC6888 through infrared observations

We present a comprehensive infrared (IR) study of the iconic Wolf-Rayet (WR) wind-blown bubble NGC6888 around WR136. We use Wide-field Infrared Survey Explorer (WISE), Spitzer IRAC and MIPS and Herschel PACS IR images to produce a sharp view of the distribution of dust around WR136. We complement these IR photometric observations with Spitzer IRS spectra in the 5-38 $\mu$m wavelength range. The unprecedented high-resolution IR images allowed us to produce a clean spectral energy distribution, free of contamination from material along the line of sight, to model the properties of the dust in NGC6888. We use the spectral synthesis code Cloudy to produce a model for NGC6888 that consistently reproduces its optical and IR properties. Our best model requires a double distribution with the inner shell composed only of gas, whilst the outer shell requires a mix of gas and dust. The dust consists of two populations of grain sizes, one with small sized grains $a_\mathrm{small}$=[0.002-0.008] $\mu$m and another one with large sized grains $a_\mathrm{big}$=[0.05-0.5] $\mu$m. The population of big grains is similar to that reported for other red supergiants stars and dominates the total dust mass, which leads us to suggest that the current mass of NGC6888 is purely due to material ejected from WR136, with a negligible contribution of swept up interstellar medium. The total mass of this model is 25.5$^{+4.7}_{-2.8}$ M$_{\odot}$, a dust mass of $M_\mathrm{dust}=$0.14$^{+0.03}_{-0.01}$ M$_{\odot}$, for a dust-to-gas ratio of $5.6\times10^{-3}$. Accordingly, we suggest that the initial stellar mass of WR136 was $\lesssim$50 M$_{\odot}$, consistent with current single stellar evolution models.Comment: 13 pages, 11 figures, 6 tables; Accepted to MNRA

Unidad Técnica de Geodesia, Geofísica y Magnetismo de Rocas: Laboratorio de Paleomagnetismo, Magnetismo de Rocas y Modelado Geomagnético

Trabajo presentado en la I Reunión Científica del Instituto de Geociencias (CSIC-UCM), los días 15 y 16 de septiembre de 2011.Peer reviewe

Descriptive analysis of histological types in women undergoing post mastectomy breast reconstruction

Background: Breast cancer is a pathological entity that widely compromises the life and quality of life of affected women; in addition to the great affectation to the current health services. Therefore, maintaining an accurate and complete cancer registry program is one of the most important factors in implementing national cancer control programs and evaluating the results of screening, diagnosis, and treatment. Among the current limitations in the studies, there is a gap in the study of the population undergoing breast reconstruction. Methods: A retrospective study was carried out at hospital general de México “Dr. Eduardo Licéaga” with the information from the clinical records of the period 2019-2020. Patients undergoing breast reconstruction after mastectomy with histological report were included. Through non-probabilistic sampling, a population of 138 women was formed. For data analysis, frequencies and percentages were calculated for the qualitative variables; while for the quantitative variables, mean and standard deviation were calculated. Results: 138 women who underwent breast reconstruction were included, the mean age was 49.9±10.85 years, the mean BMI was 26.80±4.62 kg/m2, the secondary educational level predominated (34.8%), radiotherapy was applied to 34.1%, reconstruction was late in 75.4%, the most frequent reconstruction technique was TRAM flap (44.2%), the histological type of invasive ductal carcinoma predominated (68.1%). Conclusions: In women undergoing post-mastectomy breast reconstruction, the histological type of invasive ductal carcinoma predominates.

Andrological characteristics of tropical milking criollo bulls

ABSTRACT Objective: To assess the testicular and semen characteristics in Criollo Lechero Tropical (CLT) bulls in the subhumid Mexican tropics. Design/methodology/approach: Eight bulls were included in the study and distributed in two groups: G1 (n=5): young bulls and G2 (n=3): adult bulls. All bulls were managed under grazing and were evaluated throughout one year. From each bull the following measurements were taken once a month: live weight, body condition score, scrotal circumference, and testicular width, length and volume. Semen was obtained every 3 months via artificial vagina. Semen variables evaluated in each collection were: aspect, volume, mass and individual motility, and sperm concentration and morphology. Results: Live weight and testicular measurements increased linearly during the study in bulls from both groups. All bulls had scrotal circumference larger than the minimum threshold value for cattle and semen of high quality. Study limitations/implications: The low availability of CLT bulls prevented the inclusion of a larger number of animals in the study. This low availability of animals makes it necessary to establish standard values for testicular measurements and semen characteristics in the CLT breed in order to select the best individuals as sires and contribute to its conservation. Findings/conclusions:The CLT bulls had good scrotal circumference and semen quality since a young age and into adulthood. These traits make the CLT bulls an important alternative for livestock breeding in the tropics.Objective: To assess the testicular and semen characteristics in Criollo LecheroTropical (CLT) bulls in the subhumid Mexican tropics.Design/methodology/approach: Eight bulls were included in the study and distributedin two groups: G1 (n=5): young bulls and G2 (n=3): adult bulls. All bulls were managedunder grazing and were evaluated throughout one year. From each bull the followingmeasurements were taken once a month: live weight, body condition score, scrotalcircumference, and testicular width, length and volume. Semen was obtained every 3months via artificial vagina. Semen variables evaluated in each collection were: aspect,volume, mass and individual motility, and sperm concentration and morphology. Results: Live weight and testicular measurements increased linearly during the study inbulls from both groups. All bulls had scrotal circumference larger than the minimumthreshold value for cattle and semen of high quality.Study limitations/implications: The low availability of CLT bulls prevented theinclusion of a larger number of animals in the study. This low availability of animalsmakes it necessary to establish standard values for testicular measurements and semencharacteristics in the CLT breed in order to select the best individuals as sires andcontribute to its conservation.Findings/conclusions: The CLT bulls had good scrotal circumference and semenquality since a young age and into adulthood. These traits make the CLT bulls animportant alternative for livestock breeding in the tropics

Distributed event-triggered communication for angular speed synchronization of networked BLDC motors

[EN] This work presents the design and implementation of a collaborative and decentralized control for synchronizing the angular velocity of a group of spatially distributed brushless direct current (BLDC) motors. Via an Active Disturbance Rejection Control (ADRC), acting as an internal-loop, the dynamics of the BLDC can be assimilated to that of a first-order integrator, which is considered an agent. Then, a decentralized collaborative control strategy with event-triggered communication is proposed, which solves the problem of leader-follower consensus for the multi-agent system and thus speed synchronization. The communication topology between agents is modeled using an undirected and connected graph. The decentralized control law incorporates an event function, which indicates the instant at which the i-th agent transmits the angular velocity information to its neighbor. An experimental platform using two BLDC and a virtual leader was developed to validate the proposed approach. The experimental results show excellent performance for angular velocity consensus for regulation tasks, while the bandwidth usage is only 1.25 % regarding a periodic communication implementation.[ES] Este trabajo presenta el diseño e implementación de un control colaborativo descentralizado para la sincronización de velocidad angular de un conjunto de motores de corriente continua sin escobillas (BLDC) distribuidos espacialmente. Apoyándose de un control por rechazo activo de perturbaciones, actuando como un bucle interno, la dinámica del BLDC puede asimilarse a la de un integrador de primer orden y el cual será considerado un agente. Se propone entonces una estrategia de control colaborativo descentralizado con una comunicación activada por eventos, que resuelve el problema del consenso líder-seguidor del sistema multi-agente y, con ello, la sincronización de velocidades entre motores. La topología de comunicación entre agentes se modela usando un grafo conectado y no dirigido. La ley de control descentralizado incorpora una función de evento, que indica el instante en el que $i$-ésimo agente transmite la información de velocidad angular a su vecino. El intercambio asíncrono de información permite reducir el tráfico de datos en la red de comunicaciones, lo que permite aprovechar el ancho de banda. Al analizar la dinámica de la trayectoria del error del sistema, se establece que el vector de error del sistema multi-agente tiende de forma exponencial y permanece confinado a una vecindad del origen del espacio de estados de error. Aunque la estrategia está diseñada para n-agentes, se desarrolló una plataforma experimental compuesta por dos motores y un líder virtual, permitiendo validar la estrategia. Los resultados experimentales muestran un excelente desempeño del consenso de velocidad angular de ambos motores BLDC para tareas de regulación, mientras que el uso del ancho de banda es de solamente 1.25 % con respecto a una implementación de comunicación periódica.Hernández-Méndez, A.; Guerrero-Castellanos, J.; Orozco-Urbieta, T.; Linares-Flores, J.; Mino-Aguilar, G.; Curiel, G. (2021). Comunicación distribuida activada por eventos para la sincronización de velocidad angular de motores BLDC en red. Revista Iberoamericana de Automática e Informática industrial. 18(4):360-370. https://doi.org/10.4995/riai.2021.14989OJS360370184Ahmed, N., Cortes, J., Martinez, S., 2016. Distributed control and estimation of robotic vehicle networks: Overview of the special issue-part II. IEEE Control Systems 36 (4), 18-21. https://doi.org/10.1109/MCS.2016.2558398Aranda-Escolástico, E., Guinaldo, M., Heradio, R., Chacon, J., Vargas, H., Sánchez, J., Dormido, S., 2020. 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Power active filter control based on a resonant disturbance observer. IET Power Electronics 8 (4), 554-564. https://doi.org/10.1049/iet-pel.2014.0032Garcia, E., Cao, Y., Wang, X., Casbeer, D. W., July 2015. Decentralized eventtriggered consensus of linear multi-agent systems under directed graphs. In: 2015 American Control Conference (ACC). pp. 5764-5769. https://doi.org/10.1109/ACC.2015.7172242Guerrero-Castellanos, J., Rifaï, H., Arnez-Paniagua, V., Linares-Flores, J., Saynes-Torres, L., Mohammed, S., 2018. Robust active disturbance rejection control via control lyapunov functions: Application to actuated-ankle-footorthosis. Control Engineering Practice 80, 49 - 60. https://doi.org/10.1016/j.conengprac.2018.08.008Guerrero-Castellanos, J., Vega-Alonzo, A., Durand, S., Marchand, N., Gonzalez-Diaz, V., Casta˜neda-Camacho, J., Guerrero-Sánchez, W., 2019. Leader-following consensus and formation control of vtol-uavs with eventtriggered communications. 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A backstepping approach to decentralized active disturbance rejection control of interacting boost converters. Transactions on Industry Applications 53 (4), 4063-4072. https://doi.org/10.1109/TIA.2017.2683441Lee, J., Bagheri, B., Kao, H.-A., 2015. A cyber-physical systems architecture for industry 4.0-based manufacturing systems. Manufacturing Letters 3, 18- 23. https://doi.org/10.1016/j.mfglet.2014.12.001Lewis, F. L., Zhang, H., Hengster-Movric, K., Das, A., 2013. Cooperative control of multi-agent systems: optimal and adaptive design approaches. Springer Science & Business Media. https://doi.org/10.1007/978-1-4471-5574-4Marchand, N., Durand, S., Guerrero-Castellanos, J. F., 2013. A general formula for event-based stabilization of nonlinear systems. Automatic Control, IEEE Transactions on 58 (5), 1332-1337. https://doi.org/10.1109/TAC.2012.2225493Miskowicz, M., 2015. Event-Based Control and Signal Processing. CRC Press.Neenu, T., Poongodi, P., 07 2009. Position control of dc motor using genetic algorithm based pid controller. Lecture Notes in Engineering and Computer Science 2177.Olfati-Saber, R., Murray, R. M., 2004a. Consensus problems in networks of agents with switching topology and time-delays. Automatic Control, IEEE Transactions on 49 (9), 1520-1533. https://doi.org/10.1109/TAC.2004.834113Olfati-Saber, R., Murray, R. M., Sep. 2004b. Consensus problems in networks of agents with switching topology and time-delays. IEEE Transactions on Automatic Control 49 (9), 1520-1533. https://doi.org/10.1109/TAC.2004.834113Ren, W., Beard, R. W., 2008. Distributed consensus in multi-vehicle cooperative control. Springer. https://doi.org/10.1007/978-1-84800-015-5Sánchez-Santana, J., Guerrero-Castellanos, J., Villarreal-Cervantes, M., Ramırez-Martınez, S., 2018. Control distribuido y disparado por eventos para la formación de robots m'oviles tipo (3, 0)?. In: Congreso Nacional de Control Automático.Seyboth, G. S., Dimarogonas, D. V., Johansson, K. H., 2013. Event-based broadcasting for multi-agent average consensus. Automatica 49 (1), 245-252. https://doi.org/10.1016/j.automatica.2012.08.042Shi, T., Liu, H., Geng, Q., Xia, C., 2016. Improved relative coupling control structure for multi-motor speed synchronous driving system. IET Electric Power Applications 10 (6), 451-457. https://doi.org/10.1049/iet-epa.2015.0515Sira-Ramírez, H., Hernández-Méndez, A., Linares-Flores, J., Luviano-Juarez, A., 2016. Robust flat filtering dsp based control of the boost converter. Control Theory and Technology 14 (3), 224-236. https://doi.org/10.1007/s11768-016-6025-6Sira-Ramírez, H., Linares-Flores, J., Luviano-Juárez, A., Cortés-Romero, J., 2015. Ultramodelos globales y el control por rechazo activo de perturbaciones en sistemas no lineales diferencialmente planos. Revista Iberoamericanade Automática e Informática Industrial RIAIg 12 (2), 133 - 144. https://doi.org/10.1016/j.riai.2015.02.001Song, H., Rawat, D. 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Respuesta biológica, nutricional y hematoinmune en juveniles Cherax quadricarinatus (Decapoda: Parastacidae) alimentados con mezcla probiótica

Objetivo: Evaluar indicadores biológicos, nutricionales y hematoinmunes en juveniles Cherax quadricarinatus que fueron cultivados y alimentados con una mezcla de probióticos. Materiales y métodos: Un diseño completamente aleatorizado (DCA) con seis tratamientos: 0 (control), 1×102 µL, 2×102 µL, 3×102 µL, 4×102 µL y 5×102 µL de mezcla de probióticos (Bacterol Shrimp Forte), con tres repeticiones cada una; se utilizaron 18 tanques experimentales de diametro 1.7 m y área de 2.26 m2, con una densidad de 20 juveniles (0.95±0.10 g y 7.78±0.77mm) por tanque durante 60 días. Se midieron los parámetros biológicos (peso, longitud, aumento de peso, aumento de peso, tasa de crecimiento específico, aumento de longitud, aumento de longitud y supervivencia), nutricionales (conversión alimenticia, eficiencia alimenticia y eficiencia proteica) y hematoinmune (total de hemocitos, hemocitos diferenciales, tasa fagocítica, superóxido dismutasa y estrés hipóxico). Resultados: Para los indicadores biológicos, los mejores resultados (p<0.05) se obtuvieron al utilizar 4×102 µL del probiótico (peso final: 9.11 g; longitud final: 68.95 mm; tasa de crecimiento específico: 3.74). En cuanto a los parámetros nutricionales, los mejores resultados se obtuvieron con 3×102 µL (conversion alimenticia: 1.09, eficiencia alimenticia: 0.91 y eficiencia proteica: 2.61); aunque no hubo diferencias entre 3×102 y 4×102 µL. Para la respuesta hematoinmune, hubo diferencias (p <  0.05) para todos los indicadores en estudio, con un mejor desempeño para 4×102 µL de la mezcla de probióticos. Conclusiones: La mezcla de probióticos induce la respuesta hematoinmune, biológica y nutricional con la mejor respuesta para concentraciones de 3×102 µL y 4×102 µL