Pseudo-heteroclinic connections between bicircular restricted four-body problems

In this paper, we show a mechanism to explain transport from the outer to the inner Solar system. Such a mechanism is based on dynamical systems theory. More concretely, we consider a sequence of uncoupled bicircular restricted four-body problems –BR4BP –(involving the Sun, Jupiter, a planet and an infinitesimal mass), being the planet Neptune, Uranus and Saturn. For each BR4BP, we compute the dynamical substitutes of the collinear equilibrium points of the corresponding restricted three-body problem (Sun, planet and infinitesimal mass), which become periodic orbits. These periodic orbits are unstable, and the role that their invariant manifolds play in relation with transport from exterior planets to the inner ones is discussed.Peer ReviewedPostprint (published version

Central configurations of the planar coorbital satellite problem

We study the planar central configurations of the 1 + n body problem where one mass is large and the other n masses are infinitesimal and equal. We find analytically all these central configurations when 2 ≤ n ≤ 4. Numerically, first we provide evidence that when n ≥ 9 the only central configuration is the regular n–gon with the large mass in its barycenter, and second we provide also evidence of the existence of an axis of symmetry for every central configuration

Fast numerical computation of Lissajous and quasi-halo libration point trajectories

In this paper we present a methodology for the automatic generation of quasi–periodic libration point trajectories (Lissajous and quasi–halo) of the Spatial, Circular Restricted Three–Body Problem. This methodology is based on the computation of a mesh of orbits which, using interpolation strategies, gives an accurate quantitative representation of the full set of libration point orbits. This representation, when combined with the one obtained using Poincar´e maps, provides a useful tool for the design of missions to libration points fulfilling specific requirements. The same methodology applies to stable and unstable manifolds as well. This paper extends and improves results presented in [10].Postprint (published version

Tails and bridges in the parabolic restricted three-body problem

This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.After a close encounter of two galaxies, bridges and tails can be seen between or around them. A bridge would be a spiral arm between a galaxy and its companion, whereas a tail would correspond to a long and curving set of debris escaping from the galaxy. The goal of this paper is to present a mechanism, applying techniques of dynamical systems theory, that explains the formation of tails and bridges between galaxies in a simple model, the so-called parabolic restricted three-body problem, i.e. we study the motion of a particle under the gravitational influence of two primaries describing parabolic orbits. The equilibrium points and the final evolutions in this problem are recalled,and we showthat the invariant manifolds of the collinear equilibrium points and the ones of the collision manifold explain the formation of bridges and tails. Massive numerical simulations are carried out and their application to recover previous results are also analysed.Peer ReviewedPostprint (published version

Dynamics of the parabolic restricted three-body problem

The main purpose of the paper is the study of the motion of a massless body attracted, under the Newton's law of gravitation, by two equal masses moving in parabolic orbits all over in the same plane, the planar parabolic restricted three body problem. We consider the system relative to a rotating and pulsating frame where the equal masses (primaries) remain at rest. The system is gradient like and has exactly ten hyperbolic equilibrium points lying on the boundary invariant manifolds corresponding to escape of the primaries in past and future time. The global flow of the system is described in terms of the final evolution (forwards and backwards in time) of the solutions. The invariant manifolds of the equilibrium points play a key role in the dynamics. We study the connections, restricted to the invariant boundaries, between the invariant manifolds associated to the equilibrium points. Finally we study numerically the connections in the whole phase space, paying special attention to capture and escape orbits.Peer ReviewedPostprint (author's final draft

Challenge-based learning and the Barcelona ZeroG Challenge: A space education case study

Challenge-Based Learining is a STEM Education methodology that has been used as a collaborative and hands-on approach to encourage students to put their knowledge in practice by addressing real-life problems. Space Education is a field particularly suited to apply it, with hands-on research projects which require students to take actions and communicate their efforts in a multicultural, international scenario in order to produce an optimal response a specific goal. We herein present a successful Challenge-Based Learning Case Study which involves designing, implementing, and actually flying a microgravity experiment in parabolic flight. The Barcelona ZeroG Challenge is an international competition addressed to University students worldwide. It challenges students to build a team with a mentor, propose, design, build and fly their experiment in microgravity and finally communicate their findings. The experiment has to meet the requirements of a unique microgravity research platform available in Barcelona for educational and research purposes. More than fifty students have flown their experiments on board an aerobatic CAP10B aircraft in Barcelona in previous educational campaigns; having published their results in relevant symposiums and scientific journals. These campaigns have always attracted media attention. The current edition is underway with the winner team expected to fly their experiment before the end of 2022. This edition is jointly organized by Universitat Politècnica de Catalunya, the Barcelona-Sabadell Aviation Club and the Space Generation Advisory Council. Up to fifteen projects have been submitted to this edition, an unprecedent number so far. A panel of experts from the European Space Agency Academy conducted the selection of the winner team, who receives a 2500 euros grant to develop its experiment, aside from the opportunity to fly it in parabolic flight. Furthermore, students from our own University have also the opportunity of designing and testing their microgravity experiments during their studies. Principles of Challenge-Based Learning are herein described as well as how this methodology is applied to this Case Study. Results from our experience are very satisfactory as most of the students who have been involved in it perceive this experience as a boost for their careers. Three key factors to success have been identified: a strong involvement from students' associations, a need for international cooperation and the quality of the students’ mentoring. The experience can be of interest for other organizations to conduct a successful CBL educational projec

Challenge-based learning and the Barcelona ZeroG Challenge: a space education case study

Challenge-Based Learining is a STEM Education methodology that has been used as a collaborative and hands-on approach to encourage students to put their knowledge in practice by addressing real-life problems. Space Education is a field particularly suited to apply it, with hands-on research projects which require students to take actions and communicate their efforts in a multicultural, international scenario in order to produce an optimal response a specific goal. We herein present a successful Challenge-Based Learning Case Study which involves designing, implementing, and actually flying a microgravity experiment in parabolic flight. The Barcelona ZeroG Challenge is an international competition addressed to University students worldwide. It challenges students to build a team with a mentor, propose, design, build and fly their experiment in microgravity and finally communicate their findings. The experiment has to meet the requirements of a unique microgravity research platform available in Barcelona for educational and research purposes. More than fifty students have flown their experiments on board an aerobatic CAP10B aircraft in Barcelona in previous educational campaigns; having published their results in relevant symposiums and scientific journals. These campaigns have always attracted media attention. The current edition is underway with the winner team expected to fly their experiment before the end of 2022. This edition is jointly organized by Universitat Politècnica de Catalunya, the Barcelona-Sabadell Aviation Club and the Space Generation Advisory Council. Up to fifteen projects have been submitted to this edition, an unprecedent number so far. A panel of experts from the European Space Agency Academy conducted the selection of the winner team, who receives a 2500 euros grant to develop its experiment, aside from the opportunity to fly it in parabolic flight. Furthermore, students from our own University have also the opportunity of designing and testing their microgravity experiments during their studies. Principles of Challenge-Based Learning are herein described as well as how this methodology is applied to this Case Study. Results from our experience are very satisfactory as most of the students who have been involved in it perceive this experience as a boost for their careers. Three key factors to success have been identified: a strong involvement from students' associations, a need for international cooperation and the quality of the students’ mentoring. The experience can be of interest for other organizations to conduct a successful CBL educational project.Objectius de Desenvolupament Sostenible::4 - Educació de QualitatObjectius de Desenvolupament Sostenible::4 - Educació de Qualitat::4.3 - Per a 2030, assegurar l’accés en condicions d’igualtat per a tots els homes i dones a una formació tècnica, professional i superior de qualitat, inclòs l’ensenyament universitariObjectius de Desenvolupament Sostenible::4 - Educació de Qualitat::4.5 - Per a 2030, eliminar les disparitats de gènere en l’educació i garantir l’accés en condicions d’igualtat a les persones vulnerables, incloses les persones amb discapacitat, els pobles indígenes i els nens i nenes en situacions de vulnerabilitat, a tots els nivells de l’ensenyament i la formació professionalPostprint (published version

Water

[p.4] Values at stake from the new water culture = Valors en joc des de la nova cultura de l'aigua[p.10] The role of schools in the future of water = El paper de l'àmbit escolar. el futur de l'aigua[p.13] Technocracy versus sustainability: education, ecology and management of the Baix llobregat Campus lake = Tecnocràcia vs. sostenibilitat: educació, ecologia i gestió de l'estany del Campus del Baix Llobregat[p.21] Menorca: the fresh water challenge = Menorca: el repte de l'aigua dolça[p.38] Water for people, water for life: the right to water and the role of development NGOs = Aigua per a tots, aigua per a la vida: el dret a l'aigua i el rol de les ONGD[p.43] Water you shouldn't drink...: the water crisis, sustainability and education in India = Aigua que no has de beure...: crisi dels recursos hidràulics, sostenibilitat i educació a l'Índia[p.46] Interview with Maria Rieradevall, expert in education and water = Entrevista amb Maria Rieradevall, experta en educació ambientalPeer Reviewe

Brot de parotiditis en població de joves correctament vacunada

Parotiditis; Joves; VacunacióParotiditis; Jóvenes; VacunaciónParotitis; Young people; VaccinationIntroducció. Com a conseqüència de la introducció de la vacuna el 1980, es va produir una davallada important de casos i brots de parotiditis. Tanmateix, a inicis del segle XXI hi ha hagut un augment de brots en cohorts de joves ben vacunades que posa en qüestió l’efectivitat de la vacuna. Es descriu un brot en una població de joves altament vacunada i les dificultats per controlar-lo. Mètodes. Estudi descriptiu dels casos de parotiditis notificats durant el període comprès entre el 24 d’agost del 2015 i el 12 de maig del 2016 a la comarca d’Osona. Resultats. Es notifiquen 162 casos amb una mediana d’edat de 21 anys (rang 6-56 anys). Es descriu una correlació positiva entre el nombre de casos i els anys transcorreguts des de l’última dosi de vacuna. S’indiquen mesures de prevenció i control addicionals. Conclusions. Els resultats reforcen la necessitat de continuar els programes de vacunacions i la vigilància epidemiològica de la malaltia per tenir altes cobertures vacunals i poder aplicar les mesures de prevenció i control de forma immediata. Calen més estudis per monitorar l’efectivitat d’una tercera dosi per millorar el control de brots.Introducción. Sconsecuencia de la introducción de la vacuna en 1980, se produjo una importante bajada de casos y brotes de parotiditis. Sin embargo, a inicios del siglo XXI se ha producido un aumento de brotes en cohortes de jóvenes bien vacunadas que pone en cuestión la efectividad de la vacuna. Se describe un brote en una población de jóvenes altamente vacunada y las dificultades para su control. Métodos. Estudio descriptivo de los casos de parotiditis notificados durante el periodo comprendido entre el 24 de agosto del 2015 y el 12 de mayo del 2016 en la comarca de Osona. Resultados. Se notifican 162 casos con una mediana de edad de 21 años (rango 6-56 años). Se describe una correlación positiva entre el número de casos y los años transcurridos desde la última dosis de vacuna. Se indican medidas de prevención y control adicionales. Conclusiones. Los resultados refuerzan la necesidad de continuar los programas de vacunaciones y la vigilancia epidemiológica de la enfermedad con el fin de tener altas coberturas vacunales y poder aplicar las medidas de prevención y control de forma inmediata. Son necesarios más estudios para monitorizar la efectividad de una tercera dosis para mejorar el control de brotes.Background. As a consequence of the introduction of the MMR vaccine in 1980, an important decline of cases and outbreaks of mumps occurred. But at the beginning of the 21st century there has been an increase in outbreaks affecting well vaccinated cohorts of young people that disputes the effectiveness of the vaccine. This work describes an outbreak occurring in a highly-vaccinated population of young adults and the difficulties for its control. Methods: Descriptive study of the cases of mumps reported during the period bought between August 24, 2015 and May 12, 2016 in the region of Osona. Results: 162 cases with a median age of 21 years are reported (6- 56 age range). A positive correlation between the number of cases and the years gone by from the last dose of vaccine is described. Additional prevention and control measures are indicated. Conclusions: The results reinforce the need to continue vaccination schemes and the epidemiological surveillance of the disease in order to have high vaccine coverages and be able to promptly implement prevention and control measures. More studies are needed to monitor the effectiveness of a third dose to improve outbreak control