Jet substructure at the LHC with soft collinear effective theory

This thesis investigates the use of Soft-Collinear effective theory (SCET) in order to obtain precise QCD predictions for jet substructure observables. We used SCET to obtain factorization theorems that allow us to resum towers of logarithms that become large in certain regions of phase space, improving the convergence of perturbation theory. Pushing for higher orders in logarithmic accuracy is a crucial part of having reliable predictions to be put up against data, and a necessary condition for precision. The jet substructure observables studied in this thesis are the jet shape, the angle between different jet axes, the jet energy drop, and the Soft Drop momentum sharing fraction zg

A general Markov chain approach for disease and rumour spreading in complex networks

Spreading processes are ubiquitous in natural and artificial systems. They can be studied via a plethora of models, depending on the specific details of the phenomena under study. Disease contagion and rumour spreading are among the most important of these processes due to their practical relevance. However, despite the similarities between them, current models address both spreading dynamics separately. In this article, we propose a general spreading model that is based on discrete time Markov chains. The model includes all the transitions that are plausible for both a disease contagion process and rumour propagation. We show that our model not only covers the traditional spreading schemes but that it also contains some features relevant in social dynamics, such as apathy, forgetting, and lost/recovering of interest. The model is evaluated analytically to obtain the spreading thresholds and the early time dynamical behaviour for the contact and reactive processes in several scenarios. Comparison with Monte Carlo simulations shows that the Markov chain formalism is highly accurate while it excels in computational efficiency. We round off our work by showing how the proposed framework can be applied to the study of spreading processes occurring on social networks

Design, implementation and evaluation of transnational collaborative programmes in astronomy education and public outreach

This thesis presents a study of how science can most effectively be used to engage and educate the global public and specifically describes the role of astronomy in doing this. Astronomy has a special place in the field of science education and public engagement with science. It has great appeal for large sections of the public for several reasons. We shall use astronomy as a case study to consider the effect and impact of transnational collaborations with innovative approaches and centralised coordination in science education and public outreach. The thesis is based on eight years of designing, implementing and evaluating transnational collaborative programmes in astronomy education and public outreach, from the perspective of the practitioner. We shall also show that large global science EPO projects can result in sustainable outcomes that outlive the projects themselves and analyse the various aspects of global science communication project that are necessary for their success.History of Scienc

Space Awareness: Inspiring A New Generation of Space Explorers

History of Scienc

A survey of techniques applied to non-stationary waveforms in electrical power systems

The well-known and ever-present time-varying and non-stationary nature of waveforms in power systems requires a comprehensive and precise analytical basis that needs to be incorporated in the system studies and analyses. This time-varying behavior is due to continuous changes in system configurations, linear load levels and operating modes of nonlinear load / equipment and thus present conceptual and practical challenges. The objective of this paper is to provide a comprehensive bibliographical survey of the proposed techniques to deal with time-varying and non-stationary waveforms in power systems

Dinosaur tracks from the Early Cretaceous (Albian) of Parede (Cascais, Portugal): new contributions for the sauropod palaeobiology of the Iberian Peninsula

A recently discovered Early Cretaceous (early late Albian) dinosaur tracksite at Parede beach (Cascais, Portugal) reveals evidence of dinoturbation and at least two sauropod trackways. One of these trackways can be classified as narrow-gauge, which represents unique evidence in the Albian of the Iberian Peninsula and provides for the improvement of knowledge of this kind of trackway and its probable trackmaker, in an age when the sauropod record is scarce. These dinosaur tracks are preserved on the upper surface of a marly limestone bed that belongs to the Galé Formation (Água Doce Member, middle to lower upper Albian). The study of thin-sections of the beds C22/24 and C26 in the Parede section has revealed a microfacies composed of foraminifers, radiolarians, ostracods, corals, bivalves, gastropods, and echinoids in a mainly wackestone texture with biomicritic matrix. These assemblages match with the lithofacies, marine molluscs, echinids, and ichnofossils sampled from the section and indicate a shallow marine, inner shelf palaeoenvironment with a shallowing-upward trend. The biofacies and the sequence analysis are compatible with the early late Albian age attributed to the tracksite. These tracks and the moderate dinoturbation index indicate sauropod activity in this palaeoenvironment. Titanosaurs can be dismissed as possible trackmakers on the basis of the narrow-gauge trackway, and probably by the kidney-shaped manus morphology and the pes-dominated configuration of the trackway. Narrow-gauge sauropod trackways have been positively associated with coastal palaeoenvironments, and the Parede tracksite supports this interpretation. In addition, this tracksite adds new data about the presence of sauropod pes-dominated trackways in cohesive substrates. As the Portuguese Cretaceous sauropod osteological remains are very scarce, the Parede tracksite yields new and relevant evidence of these dinosaurs. Furthermore, the Parede tracksite is the youngest evidence of sauropods in the Portuguese record and some of the rare evidence of sauropods in Europe during the Albian. This discovery enhances the palaeobiological data for the Early Cretaceous Sauropoda of the Iberian Peninsula, where the osteological remains of these dinosaurs are relatively scarce in this region of southwestern Europe. Therefore, this occurrence is also of overall interest due to its impact on Cretaceous Sauropoda palaeobiogeography.El reciente descubrimiento de huellas de dinosaurios del Cretácico Inferior (inicio del Albiense tardío) en la playa de Parede (Cascais, Portugal) ha revelado evidencias de dinoturbación y al menos dos rastros de saurópodos. Uno de ellos puede clasificarse como estrecho y representa la única evidencia de este tipo de rastros en el Albiense de la Península Ibérica. Estos nuevos datos permiten mejorar el conocimiento tanto de este tipo de rastros como de su posible productor, en una edad en la que el registro de saurópodos es escaso. Las huellas de dinosaurios se localizan en un nivel de caliza margosa perteneciente a la Formación Galé (Miembro Água Doce, Albiense medio-base del superior). El estudio de láminas delgadas de los niveles C22/24 y C26 de la sección estratigráfica de Parede ha mostrado ricas biomicrofacies compuestas por foraminíferos, radiolarios, ostrácodos, corales, bivalvos, gasterópodos y equinoideos, mayoritariamente en textura “wackestone” con matriz biomicrítica. Estas asociaciones coinciden con las litofacies, los moluscos marinos, los equínidos y los icnofósiles obtenidos en la sección, y corresponden a un paleoambiente marino somero de plataforma interna con tendencia somerizante hacia techo. Las biofacies y el análisis secuencial resultan compatibles con la edad del inicio del Albiense tardío atribuida al yacimiento. Estas huellas y el moderado índice de dinoturbación son indicadores de la actividad de saurópodos en este paleoambiente. En base a la estrechez del rastro, probablemente a la morfología arriñonada/semicircular de la mano y al hecho que se trata de un rastro “pes-dominated”, pueden descartarse a los titanosaurios como posibles productores. Los rastros estrechos han sido relacionados con paleoambientes costeros, y el yacimiento de Parede sustenta esta interpretación. Además, este yacimiento proporciona nuevos datos sobre la presencia de rastros de tipo “pes-dominated” en substratos cohesivos. Los restos osteológicos de saurópodos cretácicos portugueses son muy escasos, aportando el yacimiento de Parede una nueva y relevante evidencia de estos dinosaurios. Asimismo, el yacimiento de Parede constituye el hallazgo más moderno de saurópodos en el registro portugués, y una de las pocas evidencias de saurópodos en Europa durante el Albiense. Este descubrimiento incrementa los datos paleobiogeográficos de Sauropoda en el Cretácico Inferior en la Península Ibérica, en un período de tiempo en el que los restos de estos dinosaurios son escasos en esta región del Suroeste de Europa. Por tanto, este hallazgo muestra un elevado interés debido a su trascendencia para la paleobiogeografía de Sauropoda en el Cretácico

How astronomers perceive the societal impact of research: an exploratory study

We present an exploratory study of the perception of professional astronomers about the societal impact of astronomy. Ten semi-structured interviews with astronomers from a range of career and cultural backgrounds have been conducted to gain in-depth insight into their opinion about societal impact and their approach in realising it. The results show that the interviewees are aware of the diversity of impacts that astronomical research has. However, they are mostly active in out-reach and only a few activities are incorporated into their jobs to achieve an impact on development. There is little contact with stakeholders in industry, policy or other fields, like development. Besides, a structured approach in their personal out-reach is lacking, and assessment is only done informally. Despite the limited sample size of this study, the results indicate that a further change is necessary to engage professional astronomers with topics of development and societal impact to create action on the level of individual researchers.Science Communication and Societ

Effects of different prey and rearing densities on growth and survival of octopus maya hatchlings

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