Abstract: The objective of this study is to quantitatively estimate the probability of transmission of the SARS-CoV-2 virus inside the train carriage and to develop a simulation for the model based on the passenger demand for calculating the risk associated with origin-destination. The transmission rate of the virus in train carriage was analyzed using trip data from Pakenham Station to Flinders Street Station in Melbourne, Victoria, Australia, and the modified Wells-Riley model.

Semi-regular sequences over F2 are sequences of homogeneous elements of the algebra B(n) = F2[X1, ...,Xn]/(X21, ...,X2n), which have as few relations between them as possible. They were introduced in order to assess the complexity of Gröbner basis algorithms such as F4, F5 for the solution of polynomial equations. Despite the experimental evidence that semi-regular sequences are common, it was unknown whether there existed semi-regular sequences for all n, except in extremely trivial situations. We prove some results on the existence and non-existence of semi-regular sequences. In particular, we show that if an element of degree d in B(n) is semi-regular, then we must have n ≤3d. Also, we show that if d = 2t and n = 3d there exits a semi-regular element of degree d establishing that the bound is sharp for infinitely many n. Finally, we generalize the result of non-existence of semi-regular elements to the case of sequences of a fixed length m.

Semi-regular sequences over F2 are sequences of homogeneous elements of the algebra B(n) = F2[X1,…, Xn]/(X2 1,…, X2n), which have as few relations between them as possible. It is believed that most such systems are F2-semi-regular and this property has important consequences for understanding the complexity of Gröbner basis algorithms such as F4 and F5 for solving such systems. In fact even in one of the simplest and most important cases, that of quadratic sequences of length n in n variables, the question of the existence of semi-regular sequences for all n remains open. In this paper we present a new framework for the concept of F2-semi-regularity which we hope will allow the use of ideas and machinery from homological algebra to be applied to this interesting and important open question. First we introduce an analog of the Koszul complex and show that F2-semi-regularity can be characterized by the exactness of this complex. We show how the well known formula for the Hilbert series of a F2-semi-regular sequence can be deduced from the Koszul complex. Finally we show that the concept of first fall degree also has a natural description in terms of the Koszul complex.

Abstract: This paper studies the potential drivers of governments’ approval rates in 18 Latin American countries using Internet search query data from Google Trends and traditional data sources. It employs monthly panel data between January 2006 and December 2015. The analysis tests several specifications including traditional explanatory variables of governments’ approval rates – i.e. inflation, unemployment rate, GDP growth, output gap – and subjective explanatory variables – e.g. perception of corruption and insecurity. For the latter, it uses Internet search query data to proxy citizens’ main social concerns, which are expected to drive governments’ approval rates. The results show that the perception of corruption and insecurity, and complaints about public services have a statistically significant association with governments’ approval rates. This paper also discusses the potential of Internet search query data as a tool for policy makers to understand better citizens’ perceptions, since it provides highly anonymous and high-frequency series in real-time.

Résumé: Ce projet a ses débuts à la Institución Educativa Gonzalo Suárez Rendón, Siège San Ignacio de Tunja, Colombie, avec 16 étudiants de CE2 et CM1. Il s’agit d’un travail de recherche qui se base sur la magie pour renforcer les habiletés de compréhension et production orale en langue française. On propose la magie comme stratégie pédagogique pour renforcer, également, les connaissances préalables des enfants, en tant qu’élément motivationnel pour réveiller leur intérêt face à l’apprentissage de la langue étrangère et pour promouvoir le travail collaboratif. On constate que le processus d’enseignement - apprentissage du FLE devient un outil essentiel pour permettre une construction de connaissances significative et partagée. La deuxième étape du projet a eu lieu dans la 3ème École Primaire Expérimentale d’Evosmos, dans la ville de Thessalonique, en Grèce. Où l’on a validé les stratégies mises en marche lors de la première étape en Colombie. En plus des résultats et conclusions méthodologiques, on a constaté des expériences et analyses intéressantes en ce qui concerne l’interculturalité, la magie comme stratégie didactique et l’universalité des éléments didactiques qui touchent tant le contexte colombien que le grec. Abstract: This project began at the Institución Educativa Gonzalo Suárez Rendón, at the Sede San Ignacio of Tunja, Colombia, with 16 students of third and fourth grade. This research work is based on magic to enhance the oral comprehension and production skills in French. Magic is proposed as a teaching strategy to strengthen, likewise, children's prior knowledge, as a motivational element to awaken their interest in learning a foreign language and to promote collaborative work. We note that the teaching - learning process of french as a foreign language becomes an essential tool to allow the construction of significant and shared knowledge. The second stage of the project took place in the 3rd Primary Experimental School of Evosmos, in the city of Thessaloniki, Greece. Where we validated the strategies implemented during the first stage in Colombia. In addition to the methodological results and conclusions, there were various interesting experiences and analysis in regard to interculturality, magic as a didactic strategy and the universality of didactic elements that touch both the Colombian and the Greek context. Resumen: Este proyecto tiene sus inicios en la Institución Educativa Gonzalo Suárez Rendón, sede San Ignacio de Tunja, Colombia, con 16 estudiantes de tercer y cuarto grado. Se trata de un trabajo de investigación que se basa en la magia para reforzar las habilidades de comprensión y producción oral en lengua francesa. Se propone la magia como estrategia pedagógica para reforzar, igualmente, los conocimientos previos de los niños, como elemento motivacional para despertar su interés frente al aprendizaje de la lengua extranjera y para promover el trabajo colaborativo. Se constata que el proceso de enseñanza-aprendizaje del francés como lengua extranjera llega a ser una herramienta esencial para permitir una construcción de conocimientos significativa y compartida. La segunda etapa del proyecto tiene lugar en el 3er colegio experimental de Evosmos, en la ciudad de Salónica, en Grecia. Es allí donde se validan las estrategias propuestas durante la primera etapa en Colombia. Además de los resultados y las conclusiones metodológicas, se constata experiencias y análisis interesantes en lo que concierne a la interculturalidad, a la magia como estrategia didáctica y a la universalidad de elementos didácticos que tocan tanto el contexto colombiano como el griego.

Abstract: Colombia is the country with the highest number of internal displaced persons (IDPs) in the world, hence one of the biggest challenges for its development as a nation, in terms of peacebuilding, is to overcome the impacts that this phenomenon causes. One of them is the reconstruction of the social capital destroyed by forced displacement and the community integration of the population into the new contexts in which they return or relocate. As a proposal not just of diagnosis and measurement of needs of integration of these communities, but as a method to introduce and settle process of social capital reconstruction, this chapter presents the results of the investigation and the elaboration process of the Tool for the Measurement of Community Integrations Needs, built by the National Planning Department (DNP) and the National University of Colombia, during 2015 and 2016. This work shows the importance of privileging territorial interventions over population interventions, being more efficient and avoiding the competition among groups for resources, public services and social programs, which represent an obstacle for the community integration themselves. Likewise confirms that in the contexts where the tool was tried, the access to fundamental rights of the populations that are not IDPs is significantly lower than the access of the populations who are IDPs, despite of having similar live conditions and poverty. Furthermore, demonstrates that intangible elements as identity, sense of belonging and deep-rooted, promotes tangible elements as income-generation and socioeconomic stability, in a more effective manner than when is pursue the other way round, which is the manner as public policy in Colombia address vulnerable populations. Resumen: Colombia es el país con mayor número de desplazados internos del mundo, es por ello que uno de los retos más importantes para su desarrollo como nación, en términos de construcción de paz, es superar los impactos que ocasiona. Entre estos se encuentran la reconstrucción del capital social destruido por el desplazamiento forzado, y la integración comunitaria de la población víctima en los nuevos contextos en los que se reubica o en aquellos a los que retorna. Como propuesta no sólo de diagnóstico y medición de las necesidades de integración de las comunidades que han sido sujeto de retorno o reubicación, sino como medio para introducir y apalancar procesos de recomposición del capital social, se presentan los resultados de la investigación y del proceso de construcción y pilotaje de la Herramienta de Medición de Necesidades de Integración Comunitaria, construida entre el Departamento Nacional de Planeación y la Universidad Nacional de Colombia, durante los años 2015 y 2016. Este trabajo conjunto evidencia la importancia de privilegiar las intervenciones territoriales sobre las intervenciones poblacionales, al ser más eficientes y evitar promover la competencia entre grupos de personas por recursos, servicios y oferta social, lo cual representa un obstáculo en sí mismo para la integración comunitaria. Asimismo, comprueba que en los contextos en los que se piloteó la herramienta, el acceso a derechos fundamentales de la población no víctima es significativamente menor que aquella con la que cuenta la población desplazada retornada o reubicada, a pesar de tener las mismas condiciones de vida y de pobreza. Adicionalmente, demuestra que elementos inmateriales como la identidad, el sentido de pertenencia y arraigo, potencian elementos materiales como la generación de ingresos y la estabilidad socioeconómica, de forma más efectiva que si se busca hacerlo al contrario, que es la manera como se ha concebido e implementado la política pública dirigida a poblaciones vulnerables en Colombia.

Resumen: El objetivo del presente artículo es evidenciar que emociones como la empatía y la compasión son constitutivas de la política, dada la naturaleza relacional de la misma. En este sentido, señala que no es posible escindir la razón de la emoción en la política, al apelar esta al mismo tiempo al intelecto y a la afectividad, y por ende, a la capacidad cognoscitiva racional del alma humana. Es por ello que la política no puede tener lugar en escenarios de exterminio, violencia generalizada, indolencia y desprecio sistemático por la vida de los otros. Igualmente, se alude a la importancia de reivindicar la afectividad en constructos como la política y el conocimiento, para lo cual plantea una propuesta para su investigación, y enfatiza la necesidad y utilidad de hacerlo en un contexto de tanta victimización y sufrimiento como el colombiano. Abstract: The objective of this article is to show that emotions as empathy and compassion, are constituent of politics, given its relational nature. In this sense, indicates that is not possible to separate reason and emotion from politics, because of its relation with intellect and affectivity at the same time, and therefore, with the rational cognitive capacity of the human soul. Hence, politics cannot have place in scenarios of extermination, widespread violence, indolence and systematic contempt towards others’ lives. Likewise, points out the importance of asserting the affectivity in constructs as politics and knowledge, for which raise a research proposal and emphasizes the necessity and usefulness of carry it out in a context of such victimization and suffering as the Colombian.

Abstract: Using low-cost gas sensors for air quality monitoring promises cost e ective and convenient measurement systems. Nevertheless, the results obtained have a questionable quality due to di erent factors that can a ect sensor performance. The most discussed ones are relative humidity and air temperature. This investigation aimed to assess the behavior of B4-series low-cost gas sensors from Alphasense for measuring CO, NO, NO2, and O3 for di erent levels of relative humidity and temperature. These low-cost gas sensors were tested for six relative humidity levels from 10% to 85% with increasing steps of 15% and four temperature levels of 10 C, 25 C, 35 C, and 45 C against reference instruments in the laboratory. The e ect of these parameters on low-cost gas sensors was quantified in laboratory from which a correction algorithm was calculated, which was then applied to the field data. The applied algorithm improved the data quality of the low-cost gas sensors in most of the cases. Additionally, a low-cost dryer was assessed to reduce the influence of these factors on the low-cost gas sensors, which also proved to be suitable to enhance the data quality.

Abstract: Learning controllers that reproduce legged locomotion in nature have been a long-time goal in robotics and computer graphics. While yielding promising results, recent approaches are not yet flexible enough to be applicable to legged systems of different morphologies. This is partly because they often rely on precise motion capture references or elaborate learning environments that ensure the naturality of the emergent locomotion gaits but prevent generalization. This work proposes a generic approach for ensuring realism in locomotion by guiding the learning process with the spring-loaded inverted pendulum model as a reference. Leveraging on the exploration capacities of Reinforcement Learning (RL), we learn a control policy that fills in the information gap between the template model and full-body dynamics required to maintain stable and periodic locomotion. The proposed approach can be applied to robots of different sizes and morphologies and adapted to any RL technique and control architecture. We present experimental results showing that even in a model-free setup and with a simple reactive control architecture, the learned policies can generate realistic and energy-efficient locomotion gaits for a bipedal and a quadrupedal robot. And most importantly, this is achieved without using motion capture, strong constraints in the dynamics or kinematics of the robot, nor prescribing limb coordination. We provide supplemental videos.

Abstract: Bioturbation involves the incorporation of residues from the surface soil into the subsoil; however, common small soil ‘bioengineers’, such as earthworms or termites, are unlikely to transport human artifacts to deeper soil horizons. However, such artifacts occur in the deeper soil horizons within Amazonian Anthrosols (Terra Preta). Here we test the assumption that such tasks could be carried out by fly larvae, which could thus play a crucial role in waste decomposition and associated soil mixing under tropical conditions. We performed two greenhouse experiments with sandy substrate covered with layers of organic waste, ceramic fragments, and black soldier fly larvae (BSFL) (Hermetia illucens (L.) (Dipt.: Stratiomyidae)). We used in-situ images to assess the rate of bioturbation by BSFL, and then designed our main study to observe waste dissipation (reduction of organic carbon and phosphorus contents from waste model trials with and without charcoal) as related to larval-induced changes in soil properties. We found that the bioturbation of macroinvertebrates like BSFL was able to bury even large (> 5 cm) ceramic fragments within hours, which coincided with high soil growth rates (0.5 cm h-1). The sandy soil was subsequently heavily enriched with organic matter and phosphorus originating from organic waste. We conclude that BSFL, and possibly other fly species, are important, previously overlooked soil ‘bioengineers’, which may even contribute to the burial of artifacts in Anthrosols and other terrestrial waste dumps. Resumen: La bioturbación implica la incorporación de residuos del suelo superficial al subsuelo; sin embargo, es poco probable que los pequeños "bioingenieros" comunes del suelo, como las lombrices o las termitas, transporten artefactos humanos a los horizontes más profundos del suelo. Sin embargo, tales artefactos se encuentran en los horizontes más profundos del suelo dentro de los antrosoles amazónicos (Terra Preta). Aquí probamos la suposición de que tales tareas podrían ser llevadas a cabo por larvas de mosca, que podrían así desempeñar un papel crucial en la descomposición de residuos y la mezcla de suelos asociada en condiciones tropicales. Realizamos dos experimentos en invernadero con sustrato arenoso cubierto con capas de residuos orgánicos, fragmentos de cerámica y larvas de mosca soldado negra (Hermetia illucens (L.) (Dipt.: Stratiomyidae)). Utilizamos imágenes in situ para evaluar la tasa de bioturbación por parte de las BSFL, y luego diseñamos nuestro estudio principal para observar la disipación de los residuos (reducción de los contenidos de carbono orgánico y fósforo de los ensayos de modelos de residuos con y sin carbón vegetal) en relación con los cambios inducidos por las larvas en las propiedades del suelo. Encontramos que la bioturbación de macroinvertebrados como BSFL fue capaz de enterrar incluso fragmentos cerámicos grandes (> 5 cm) en cuestión de horas, lo que coincidió con altas tasas de crecimiento del suelo (0,5 cm h-1). El suelo arenoso se enriqueció posteriormente con materia orgánica y fósforo procedente de residuos orgánicos. Concluimos que las BSFL, y posiblemente otras especies de moscas, son importantes "bioingenieros" del suelo, hasta ahora ignorados, que pueden incluso contribuir al enterramiento de artefactos en antrosoles y otros vertederos terrestres.