Societies in the wild: cooperation, norms, and hierarchies

Mención Internacional en el título de doctorThis research has been funded in part by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” through grant PGC2018-098186-B-I00 (BASIC).Programa de Doctorado en Ingeniería Matemática por la Universidad Carlos III de MadridPresidente: Sandro Meloni.- Secretaria: Francesca Lipari.- Vocal: Giulia Andrighett

Fire legacies in Mediterranean streams: the key roles of the riparian canopy and the top predator on food webs

[eng] Wildfires are expected to increase in frequency and intensity because of climate change and changes in land use and management. In last decades, the research on fire effects on aquatic systems has grown, but it has been mainly conducted in the short- and mid-term (<5 years). Therefore, longer time frames are needed to assess fire effects on freshwater ecosystems. For instance, fire impacts on riparian and upland forests can be long-lived and wildfires often extirpate fish populations from streams, which may not recover due to barriers within the river network. Regarding fish extirpations, it is worth noting that freshwater fish are one of the most threatened fauna worldwide, especially the small-bodied species. In this context, the overarching goal of this PhD thesis was to investigate the long-term effects of a wildfire in Mediterranean streams. Specifically, this PhD thesis covered the indirect effects of two fire legacies: (1) the riparian canopy reduction and (2) the local extinction of the top predator in these streams, the endangered small-bodied fish Barbus meridionalis. The findings of this PhD thesis showed how the fire legacy in the riparian forest accelerated leaf-litter breakdown in an intermittent Mediterranean stream eight years after fire. The opening of the riparian forest canopy by fire increased light levels and water temperatures and reduced terrestrial-to-aquatic litter inputs. The increased water temperatures engendered by removal of canopy cover enhanced microbial mediated leaf breakdown. The reduction in leaf-litter inputs probably led to lower benthic organic matter levels, bringing to the observed increased shredder aggregation in leaf packs, thereby accelerating leaf breakdown rates. Our results demonstrated that the apex consumer was functionally irreplaceable, its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. Our mesocom experiment showed that Barbus meridionalis absence led to 'mesopredator release, and also to 'prey release despite intraguild predation, which contrasted with traditional food web theory. Top predator extirpation also changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. Moreover, we studied the feeding ecology of B. meridionalis from a functional perspective. Our results indicated that prey morphological and behavioral traits may explain prey vulnerability to predation. Specifically, the trait-based analysis showed that 10 of the 13 traits tested significantly influenced food choice (e.g. body size, concealment, locomotion, aggregation tendency, feeding habits). In addition, the leaf bags experiment confirmed that top predator absence enhanced leaf-litter breakdown, which was caused by the increase in shredder and scraper biomass in the absence of the predatory fish top-down control. Fish absence reduced leaf fungal biomass, but did not decrease microbially mediated leaf breakdown. These results suggested that leaf fungal biomass was stimulated from the bottom-up through nutrient recycling by the top predator. This PhD thesis demonstrated that past fires may have current influence on the structure and function of Mediterranean streams. Moreover, our findings evidenced that intermittent streams can be affected by the consequences of apex consumers’ extinctions, and that the loss of small-bodied top predators can lead to complex ecosystem changes. This PhD thesis interconnected several current topics in ecology research (i.e. fire effects on aquatic systems, top predator declines, and intermittent streams). Its relevance lies in the projected increase in fires in the Mediterranean region and in the current high extinction risk of small-bodied fish in freshwater ecosystems.[spa] Debido al cambio climático y a los cambios en el uso y la gestión de la tierra, se espera que la frecuencia e intensidad de los incendios forestales aumenten. La mayoría de los estudios sobre los efectos de los incendios forestales en los ecosistemas acuáticos continentales cubren el corto y medio plazo (<5 años), siendo necesarias series temporales más largas. En este contexto, el objetivo general de esta tesis doctoral fue investigar los efectos a largo plazo de un incendio forestal en ríos mediterráneos. En concreto, esta tesis doctoral se centra en los efectos de dos legados del fuego: (1) la reducción de la cobertura del bosque de ribera y (2) la extinción local del superdepredador en estos ríos, Barbus meridionalis, un pez amenazado de pequeño tamaño. Los resultados de esta tesis doctoral probaron cómo el legado del fuego en el bosque de ribera aceleró la descomposición de la hojarasca en un arroyo mediterráneo intermitente ocho años después del incendio. Nuestros resultados también demostraron que el superdepredador era funcionalmente insustituible. Nuestro experimento de mesocosmos mostró que la ausencia de Barbus meridionalis provocó el incremento de los depredadores y de los consumidores primarios, y redujo la producción primaria del perifiton. El estudio de la ecología trófica de B. meridionalis desde una perspectiva funcional reveló que los rasgos morfológicos y de comportamiento de los macroinvertebrados pueden explicar su vulnerabilidad a la depredación. Esta tesis también confirmó que la ausencia del superdepredador modificó otra función clave del ecosistema, aceleró la descomposición de las hojas. Nuestros resultados también sugirieron que el superdepredador tiene un papel clave en el reciclado de nutrientes. Esta tesis doctoral ha demostrado que los incendios del pasado pueden influir en la estructura y función actual de los ríos mediterráneos. Además, también ha evidenciado que los ríos intermitentes pueden verse afectados por las consecuencias de la extinción de sus superdepredadores. La relevancia de esta tesis doctoral radica en el incremento esperado de los incendios forestales en la región mediterránea y en el alto riesgo de extinción de los peces de pequeño tamaño en los ecosistemas acuáticos continentales

Modelos de formación de redes socioeconomicas

El objetivo del presente trabajo es la modelización matemática de la formación de redes sociales y económicas y su posterior evolución. En una sociedad tan conectada como la actual, la reputación es una herramienta indispensable para guiar las decisiones económicas y sociales con individuos desconocidos; por ello, es importante conocer cómo crecen y se desarrollan las redes que forman las personas en función de la reputación de las mismas. En este proyecto se ha realizado un modelo matemático que intenta simular el comportamiento observado en los experimentos llevados a cabo en la Universidad de Lausanne y en el Ecole Polytechnique Fédérale of Lausanne, y obtener a partir de dicho modelo unas leyes que los expliquen. Se ha conseguido un modelo que, con solo dos parámetros, es capaz de simular el comportamiento observado. Se obtiene además una interpretación cuantitativa de la reputación. Esta se construye, en el modelo, como resultado de las interacciones de los agentes, que juegan al Dilema del Prisionero en redes dinámicas.Ingeniería en Tecnologías Industriale

Influence of the track quality and of the properties of the wheel rail rolling contact on vehicle dynamics

This work describes an analytical approach to determine what degree of accuracy is required in the definition of the rail vehicle models used for dynamic simulations. This way it would be possible to know in advance how the results of simulations may be altered due to the existence of errors in the creation of rolling stock models, whilst also identifying their critical parameters. This would make it possible to maximize the time available to enhance dynamic analysis and focus efforts on factors that are strictly necessary.In particular, the parameters related both to the track quality and to the rolling contact were considered in this study. With this aim, a sensitivity analysis was performed to assess their influence on the vehicle dynamic behaviour. To do this, 72 dynamic simulations were performed modifying, one at a time, the track quality, the wheel-rail friction coefficient and the equivalent conicity of both new and worn wheels. Three values were assigned to each parameter, and two wear states were considered for each type of wheel, one for new wheels and another one for reprofiled wheels.After processing the results of these simulations, it was concluded that all the parameters considered show very high influence, though the friction coefficient shows the highest influence. Therefore, it is recommended to undertake any future simulation job with measured track geometry and track irregularities, measured wheel profiles and normative values of wheel-rail friction coefficient

Economic Model Predictive Control for Smart and Sustainable Farm Irrigation

The joint effects of rise of global population, climate change and water scarcity makes the shift towards an efficient and sustainable agriculture more and more urgent. Fortunately, recent developments in low-cost, IoT-based sensors and actuators can help us to incorporate advanced control techniques for efficient irrigation system. This paper proposes the use of an economic model predictive control at a farm scale. The controller makes use of soil moisture data sent by the sensors, price signals, operative restrictions, and accurate dynamical models of water dynamics in the soil. Its performance is demonstrated through simulations based on a real case-study, showing that it is possible to obtain significant reductions in water and energy consumption and operation costs

Pulse-based, Periodic MPC for Irrigation in Smart and Sustainable Agriculture

The growing population, together with global warming and the difficulty of accessing water, makes the increase of efficient and sustainable agriculture a priority. Undoubtedly, the recent development of low-cost IoT-based sensors and actuators presents great opportunities in this direction, since these devices can be easily deployed to implement advanced monitoring and irrigation control techniques at a farm scale. This paper proposes a pulse-based, periodic, economic predictive controller. Its goal is to find the irrigation pulse trains that optimize water and energy consumption while ensuring adequate levels of soil moisture for the crops. For this purpose, the developed MPC makes use of soil moisture data at different depths, sent by a set of field sensors, and formulates a constrained optimization problem that takes into account water costs, electricity prices, and an accurate dynamical nonlinear agro-hydrological model. Its performance is tested by simulating real case studies, which show that water and energy consumption can be significantly reduced

Economic model predictive control for smart and sustainable agriculture

The joint effects of rise of global population, climate change and water scarcity makes the shift towards an efficient and sustainable agriculture more and more urgent. Fortunately, recent developments in low-cost, IoT-based sensors and actuators can help us to incorporate advanced control techniques for efficient irrigation system. This paper proposes the use of an economic model predictive control at a farm scale. The controller makes use of soil moisture data sent by the sensors, price signals, operative restrictions, and accurate dynamical models of water dynamics in the soil. Its performance is demonstrated through simulations based on a real case-study, showing that it is possible to obtain significant reductions in water and energy consumption and operation costs.This research was partially funded by the proyect INNOREGA: Riego sostenible basado en monitorización distribuida e inteligencia artificial (PP.AVA.AVA2019.024). This project is co-financed by the FEDER funds (UE) within the “Programa Operativo de Andalucía 2014–2020”

Wi-Fi Handshake: analysis of password patterns in Wi-Fi networks

This work is supported by the General Directorate of Culture, Education and University Management of Xunta de Galicia (Ref. ED431G/01, ED431D 2017/16), the Galician Network for Colorectal Cancer Research (Ref. ED431D 2017/23), Competitive Reference Groups (Ref. ED431C 2018/49) and the Spanish Ministry of Economy and Competitiveness via funding of the unique installation BIOCAI (UNLC08-1E-002, UNLC13-13-3503) and the European Regional Development Funds (FEDER). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.[Abstract]: This article seeks to provide a snapshot of the security of Wi-Fi access points in the metropolitan area of A Coruña. First, we discuss the options for obtaining a tool that allows the collection and storage of auditable information from Wi-Fi networks, from location to signal strength, security protocol or the list of connected clients. Subsequently, an analysis is carried out aimed at identifying password patterns in Wi-Fi networks with WEP, WPA and WPA2 security protocols. For this purpose, a password recovery tool called Hashcat was used to execute dictionary or brute force attacks, among others, with various word collections. The coverage of the access points in which passwords were decrypted is displayed on a heat map that represents various levels of signal quality depending on the signal strength. From the handshakes obtained, and by means of brute force, we will try to crack as many passwords as possible in order to create a targeted and contextualized dictionary both by geographical location and by the nature of the owner of the access point. Finally, we will propose a contextualized grammar that minimizes the size of the dictionary with respect to the most used ones and unifies the decryption capacity of the combination of all of them.Xunta de Galicia; ED431G/01Xunta de Galicia; ED431D 2017/16Xunta de Galicia; ED431D 2017/23Xunta de Galicia; ED431C 2018/4

What Do Students Know about Rivers and Their Management? Analysis by Educational Stages and Territories

The overall purpose of this study was to assess the knowledge that students have about the ecosystem concept of rivers and their sustainable management. A survey of nine questions gathered responses from 3447 students at three different Spanish education levels (Primary, Secondary, and bachelor’s degree in Primary Education) and six different geographic territories in the Iberian Peninsula. Respondents showed a limited understanding of rivers, much simpler than the ecosystem concept, which was related to proposals of unsustainable management of these ecosystems. Although the results were analogous among territories, undergraduate students had a more complex concept of rivers as well as more sustainable ideas regarding their management compared with Primary and Secondary Education students. This study demonstrates the lack of knowledge transfer between science and students regarding river ecosystems. Current educational programs should be adapted to address, even at early stages of education, the sustainability challenges around river ecosystems

TREE STRUCTURE IN THE FOREST OF PINDO MIRADOR BIOLOGICAL STATION, PASTAZA, ECUADOR

The objective of this research was to characterize the arboreal structure of the evergreen piedmont forest of the Pindo Mirador biological station, Pastaza, Ecuador. Eight plots of 0.1 ha were systematically established; all trees were measured with D1. 30 from the floor ≥ 10 cm, and its total height. The abundance data by species and plots, diameter classes and height ranges were taken to be analyzed with descriptive statistics, and by means of non-parametric Kruskal-Wallis comparisons to verify differences between them. The contribution of species to the structure of the forest was evaluated by determining indices of structural diversity, including the Importance Value Index (IVI) of species, and their basal area. The results show a richness of 89 species belonging to 58 genera from 39 families, where trees with diameters between 10 and 20 cm and heights between 8 and 20 m predominate. It is concluded that it is a relatively homogeneous forest, with typical elements of the Andean-Amazonian transition, whose vertical structure of the dominant flight is of the middle or sub-canopy, moderately dense, dominated by trees of Iriartea deltoidea Ruiz & Pav., Alchornea latifolia Swartz, Hyeronima oblonga (Tul.) Müll. Arg. and Piptocoma discolor (Kunth) Pruski, those that have the greatest impact on its structure