Real-time evolution of a large-scale relativistic jet

Context. Astrophysical jets are ubiquitous in the Universe on all scales, but their large-scale dynamics and evolution in time are hard to observe since they usually develop at a very slow pace. Aims. We aim to obtain the first observational proof of the expected large-scale evolution and interaction with the environment in an astrophysical jet. Only jets from microquasars offer a chance to witness the real-time, full-jet evolution within a human lifetime, since they combine a 'short', few parsec length with relativistic velocities. Methods. The methodology of this work is based on a systematic recalibraton of interferometric radio observations of microquasars available in public archives. In particular, radio observations of the microquasar GRS 1758-258 over less than two decades have provided the most striking results. Results. Significant morphological variations in the extended jet structure of GRS 1758-258 are reported here that were previously missed. Its northern radio lobe underwent a major morphological variation that rendered the hotspot undetectable in 2001 and reappeared again in the following years. The reported changes confirm the Galactic nature of the source. We tentatively interpret them in terms of the growth of instabilities in the jet flow. There is also evidence of surrounding cocoon. These results can provide a testbed for models accounting for the evolution of jets and their interaction with the environment.Comment: 5 pages, 3 figures, 2 tables. Accepted for publication in Astronomy and Astrophysics Letter

Nuevas estrategias docentes en Histología. Más aprendizaje y menos enseñanza: Uso de microscopios virtuales e Historrelatos.

Current teaching at the University needs novel methodologies to increase students’ motivation. Here, we present two approaches to engage the student body to Human Histology subject at the University of Malaga. Virtual teaching was propelled by the COVID-19 crisis and confinement. The software for the study of histological/histopathological samples has become a valuable tool. Moreover, digital competences are in high demand within the biomedical field but students usually do not receive sufficient training. For these reasons, we have implemented the use of virtual microscopy (VM, Olympus), sharing 66 digitalized slides accessible under a username/password. VM provides real-time dynamic microscopy and offers an innovative experience at exceptionally high resolution. VM allows students to explore the samples online from anywhere, favoring autonomy and self-learning. Moreover, VM enables capturing specific tissue areas using these pictures to ask specific questions. On the other hand, transversal competences such as reading and writing skills, along with synthesis capability can be underdeveloped in our students. We initiated the activity of writing stories about histology contents (Histostories). Professional graphic designers from a webpage of scientific divulgation (masscience.com) illustrated the first story about erythrocytes. We conducted a survey among medical students to analyze the impact of this narration on their learning. Most of them welcome the initiative, considering it as an appropriate and enjoyable instrument for summarizing and revising the concepts. Immunity was among the topics more demanded between the students. Finally, we encouraged our students to write their own Histostories mentored by our teaching staff. These stories are shared through the virtual campus and on masscience website. So far, two medical students are collaborating with us in this experimental project that we expect it will bring more benefits to both readers and participants.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Are T Tauri stars gamma-ray emitters?

T Tauri stars are young, low-mass, pre-main-sequence stars surrounded by an accretion disk. These objects present strong magnetic activity and powerful magnetic reconnection events. Strong shocks are likely associated with fast reconnection in the stellar magnetosphere. Such shocks can accelerate particles up to relativistic energies. We aim at developing a simple model to calculate the radiation produced by non-thermal relativistic particles in the environment of T Tauri stars. We want to establish whether this emission is detectable at high energies with the available or forthcoming γ-ray telescopes. We assume that particles (protons and electrons) pre-accelerated in reconnection events are accelerated at shocks through the Fermi mechanism and we study the high-energy emission produced by the dominant radiative processes. We calculate the spectral energy distribution of T Tauri stars up to high energies and we compare the integrated flux obtained with that from a specific Fermi source, 1FGL J1625.8-2429c, that we tentatively associate with this kind of young stellar object. We suggest that under reasonable general conditions nearby T Tauri stars might be detected at high energies and be responsible for some unidentified Fermi sources on the Galactic plane.Instituto Argentino de RadioastronomíaFacultad de Ciencias Astronómicas y Geofísica

Real-time evolution of a large-scale relativistic jet

Context. Astrophysical jets are ubiquitous in the Universe on all scales, but their large-scale dynamics and evolution in time are hard to observe since they usually develop at a very slow pace. Aims. We aim to obtain the first observational proof of the expected large-scale evolution and interaction with the environment in an astrophysical jet. Only jets from microquasars offer a chance to witness the real-time, full-jet evolution within a human lifetime, since they combine a "short", few parsec length with relativistic velocities. Methods. The methodology of this work is based on a systematic recalibraton of interferometric radio observations of microquasars available in public archives. In particular, radio observations of the microquasar GRS 1758-258 over less than two decades have provided the most striking results. Results. Significant morphological variations in the extended jet structure of GRS 1758-258 are reported here that were previously missed. Its northern radio lobe underwent a major morphological variation that rendered the hotspot undetectable in 2001 and reappeared again in the following years. The reported changes confirm the Galactic nature of the source. We tentatively interpret them in terms of the growth of instabilities in the jet flow. There is also evidence of surrounding cocoon. These results can provide a testbed for models accounting for the evolution of jets and their interaction with the environment.Instituto Argentino de RadioastronomíaFacultad de Ciencias Astronómicas y Geofísica

El sistema de cohesión social y sus efectos en la tasa de delincuencia

Se describe el comportamiento de la tasa de delincuencia a partir de la cohesión social. Se toma como referencia la teoría general de sistemas y tiene como elemento base el cálculo con geometría analítica, pues a través de esta herramienta matemática pudo predecirse teóricamente que el nivel de cohesión es un factor detonante del dinamismo de la tasa de delincuencia, es decir, "a mayor cohesión social, menor tasa de delincuencia".This article gives a description of the behavior of the crime rate from the social cohesion, by reference to the General Systems Theory and having as a base element calculations with analytical geometry. While using this mathematical tool it was predicted theoretically that the level of cohesion is a trigger factor of the dynamism of the crime rate, so it means that "the greater the social cohesion, the lower the crime rate". (author's abstract

New teaching strategies in Histology. More learning and less teaching

Las transformaciones de la educación Médica conciernen a la Histología, ocasionando reducciones en la carga docente y asignación de créditos, redefinición de competencias y objetivos de aprendizaje, así como una creciente orientación médica de sus contenidos y una disminución de las clases magistrales. Por ello se hace necesario el empleo de nuevos métodos que se aproximen más al aprendizaje que a la enseñanza, pero que no supongan ni un aumento de la carga docente del alumnado ni un incremento de los ya hipertrofiados planes de estudios. En la Facultad de Medicina de Málaga hemos implementado nuevas metodologías docentes: orientación médica , clase inversa, ABP, microscopia virtual, HistolCasts), HistolWord, Instagram, Historrelatos), y evaluación continua . Sobre estas actividades los estudiantes han mostrado un alto grado de participación y satisfacción, estimulando su interés y motivación por la Histología y mejorando el rendimiento académico. Adicionalmente, muchas de estas estrategias se pueden extrapolar a otras áreas de la educación médica, tanto para estudiantes como para residentes y formación continuada. Algunas de estas metodologías ya han sido ya presentadas y otras lo serán por algunos de mis compañeros. Me voy a referir a continuación al HistolWord. Se trata de una actividad de gamificación basada en el juego del pasapalabra, empleando términos histológicos. Se formaron 32 equipos de 5 estudiantes que compitieron en un sistema de eliminatorias desde dieciseisavos de final, confeccionándose 70 roscos de palabras. Todo se desarrollaba en un aula con casi 200 estudiantes, donde se leían las preguntas y se proyectaba el rosco, de manera que no solo participaban los dos equipos que se enfrentaban en ese momento, sino todos los presentes. Los estudiantes indicaron la utilidad de HistolWord como motivación para el estudio, complemento de las clases, revisión y aplicaciones médicas, existiendo una correlación positiva con las calificaciones.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Longitudinal Analysis of Plantar Pressures with Wear of a Running Shoe

Running shoes typically have a lifespan of 300–1000 km, and the plantar pressure pattern during running may change as the shoe wears. So, the aim of this study was to determine the variation of plantar pressures with shoe wear, and the runner’s subjective sensation. Maximun Plantar Pressures (MMP) were measured from 33 male recreational runners at three times during a training season (beginning, 350 km, and 700 km) using the Biofoot/IBV® in-shoe system (Biofoot/IBV®, Valencia, Spain). All the runners wore the same shoes (New Balance® 738, Boston, MA, USA) during this period, and performed similar training. The zones supporting most pressure at all three study times were the medial (inner) column of the foot and the forefoot. There was a significant increase in pressure on the midfoot over the course of the training season (from 387.8 to 590 kPa, p = 0.003). The runners who felt the worst cushioning under the midfoot were those who had the highest peak pressures in that area (p = 0.002). The New Balance® 738 running shoe effectively maintains the plantar pressure pattern after 700 km of use under all the zones studied except the midfoot, probably due to material fatigue or deficits of the specific cushioning systems in that area.Junta de Extremadura y Fondo Europeo de Desarrollo Regional (FEDER) GR15073 y GR1817

Are T Tauri stars gamma-ray emitters?

T Tauri stars are young, low mass, pre-main sequence stars surrounded by an accretion disk. These objects present strong magnetic activity and powerful magnetic reconnection events. Strong shocks are likely associated with fast reconnection in the stellar magnetosphere. Such shocks can accelerate particles up to relativistic energies. We aim at developing a simple model to calculate the radiation produced by non-thermal relativistic particles in the environment of T Tauri stars. We want to establish whether this emission is detectable at high energies with the available or forthcoming gamma-ray telescopes. We assume that particles (protons and electrons) pre-accelerated in reconnection events are accelerated at shocks through Fermi mechanism and we study the high-energy emission produced by the dominant radiative processes. We calculate the spectral energy distribution of T Tauri stars up to high-energies and we compare the integrated flux obtained with that from a specific Fermi source, 1FGL J1625.8-2429c, that we tentatively associate with this kind of young stellar objects (YSOs). We suggest that under reasonable general conditions nearby T Tauri stars might be detected at high energies and be responsible for some unidentified Fermi sources on the Galactic plane.Comment: 7 pages, 10 figure