13,934 research outputs found

    Modelling uncertainties for measurements of the H → γγ Channel with the ATLAS Detector at the LHC

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    The Higgs boson to diphoton (H → γγ) branching ratio is only 0.227 %, but this final state has yielded some of the most precise measurements of the particle. As measurements of the Higgs boson become increasingly precise, greater import is placed on the factors that constitute the uncertainty. Reducing the effects of these uncertainties requires an understanding of their causes. The research presented in this thesis aims to illuminate how uncertainties on simulation modelling are determined and proffers novel techniques in deriving them. The upgrade of the FastCaloSim tool is described, used for simulating events in the ATLAS calorimeter at a rate far exceeding the nominal detector simulation, Geant4. The integration of a method that allows the toolbox to emulate the accordion geometry of the liquid argon calorimeters is detailed. This tool allows for the production of larger samples while using significantly fewer computing resources. A measurement of the total Higgs boson production cross-section multiplied by the diphoton branching ratio (σ × Bγγ) is presented, where this value was determined to be (σ × Bγγ)obs = 127 ± 7 (stat.) ± 7 (syst.) fb, within agreement with the Standard Model prediction. The signal and background shape modelling is described, and the contribution of the background modelling uncertainty to the total uncertainty ranges from 18–2.4 %, depending on the Higgs boson production mechanism. A method for estimating the number of events in a Monte Carlo background sample required to model the shape is detailed. It was found that the size of the nominal γγ background events sample required a multiplicative increase by a factor of 3.60 to adequately model the background with a confidence level of 68 %, or a factor of 7.20 for a confidence level of 95 %. Based on this estimate, 0.5 billion additional simulated events were produced, substantially reducing the background modelling uncertainty. A technique is detailed for emulating the effects of Monte Carlo event generator differences using multivariate reweighting. The technique is used to estimate the event generator uncertainty on the signal modelling of tHqb events, improving the reliability of estimating the tHqb production cross-section. Then this multivariate reweighting technique is used to estimate the generator modelling uncertainties on background V γγ samples for the first time. The estimated uncertainties were found to be covered by the currently assumed background modelling uncertainty

    Walking with the Earth: Intercultural Perspectives on Ethics of Ecological Caring

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    It is commonly believed that considering nature different from us, human beings (qua rational, cultural, religious and social actors), is detrimental to our engagement for the preservation of nature. An obvious example is animal rights, a deep concern for all living beings, including non-human living creatures, which is understandable only if we approach nature, without fearing it, as something which should remain outside of our true home. “Walking with the earth” aims at questioning any similar preconceptions in the wide sense, including allegoric-poetic contributions. We invited 14 authors from 4 continents to express all sorts of ways of saying why caring is so important, why togetherness, being-with each others, as a spiritual but also embodied ethics is important in a divided world

    BECOMEBECOME - A TRANSDISCIPLINARY METHODOLOGY BASED ON INFORMATION ABOUT THE OBSERVER

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    ABSTRACT Andrea T. R. Traldi BECOMEBECOME A Transdisciplinary Methodology Based on Information about the Observer The present research dissertation has been developed with the intention to provide practical strategies and discover new intellectual operations which can be used to generate Transdisciplinary insight. For this reason, this thesis creates access to new knowledge at different scales. Firstly, as it pertains to the scale of new knowledge generated by those who attend Becomebecome events. The open-source nature of the Becomebecome methodology makes it possible for participants in Becomebecome workshops, training programmes and residencies to generate new insight about the specific project they are working on, which then reinforce and expand the foundational principles of the theoretical background. Secondly, as it pertains to the scale of the Becomebecome framework, which remains independent of location and moment in time. The method proposed to access Transdisciplinary knowledge constitutes new knowledge in itself because the sequence of activities, described as physical and mental procedures and listed as essential criteria, have never been found organised 6 in such a specific order before. It is indeed the order in time, i.e. the sequence of the ideas and activities proposed, which allows one to transform Disciplinary knowledge via a new Transdisciplinary frame of reference. Lastly, new knowledge about Transdisciplinarity as a field of study is created as a consequence of the heretofore listed two processes. The first part of the thesis is designated ‘Becomebecome Theory’ and focuses on the theoretical background and the intellectual operations necessary to support the creation of new Transdisciplinary knowledge. The second part of the thesis is designated ‘Becomebecome Practice’ and provides practical examples of the application of such operations. Crucially, the theoretical model described as the foundation for the Becomebecome methodology (Becomebecome Theory) is process-based and constantly checked against the insight generated through Becomebecome Practice. To this effect, ‘information about the observer’ is proposed as a key notion which binds together Transdisciplinary resources from several studies in the hard sciences and humanities. It is a concept that enables understanding about why and how information that is generated through Becomebecome Practice is considered of paramount importance for establishing the reference parameters necessary to access Transdisciplinary insight which is meaningful to a specific project, a specific person, or a specific moment in time

    Botanical Journeys and China's Colonial Frontiers: 1840-1940

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    Over recent years, a body of scholarship has emerged on the topic of European and American travel writing in China. This thesis contributes to this growing field by examining four writers who travelled in China and worked as plant collectors and botanists. Largely forgotten today, these writers were influential and successful in their own day. Despite differences in geographical location and historical period, there are a number of common links that make a comparison of these travel writings productive. As travellers seeking botanical rarity and novelty, these writers explored regions of China unknown in the West, which over a period of one hundred years expanded outwards from the fringes of the treaty port areas to more remote regions of China's southwest. These writers, therefore, were on the frontiers of Western knowledge of China, and an examination of their writing provides important insights into the ways in which racial, geographical, and ecological differences were articulated and understood in the context of colonial and scientific exploration. While discussing how such differences have imperial significance, this study will also call attention to the instability of colonialist discourse in the context of China. Rather than focus exclusively on questions of imperialism, this study will show how representations of China's periphery regions also speak to metropolitan literary and cultural concerns, and a close reading of these travel writings shows that China offered powerful imaginary landscapes for home audiences. This project is organised chronologically and the chapters are divided according to the authors, with the exception of the first chapter where I introduce the historical and theoretical framework of the study and the final concluding chapter where I consider the significance of this study in the context of modern China

    Identification of new regenerative therapies in reproductive medicine and their application as a future therapeutic approach for endometrial regeneration

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    El útero es uno de los principales órganos internos del sistema reproductor femenino. Está compuesto de tres capas tisulares: perimetrio, miometrio y endometrio. Esta última capa recubre la cavidad intrauterina y es responsable directa de la implantación embrionaria (para la cual necesita un grosor endometrial mínimo). Entre las patologías que afectan al endometrio pueden distinguirse, entre otras, la atrofia endometrial (insuficiente grosor endometrial) y el síndrome de Asherman (presencia de adhesiones intrauterinas y tejido fibrótico), las cuales conforman el hilo conductor de esta tesis, compuesta de 4 artículos científicos. En ambos casos, el tejido endometrial se encuentra degenerado, lo que dificulta la implantación embrionaria, ocasionando problemas de fertilidad. A día de hoy, ninguna de estas patologías cuenta con una cura totalmente efectiva. Hasta el momento, una de las opciones terapéuticas más prometedora es la inyección de células madre. Por ello, el primer objetivo de esta tesis fue evaluar como la inyección de células madre derivadas de la médula ósea (aisladas con la detección del antígeno CD133), que había resultado ser efectiva tanto en un modelo humano como en uno animal, estaba modificando el endometrio molecularmente. Para así, intentar entender cuáles son los mecanismos paracrinos a través de los cuales llevan a cabo su acción terapéutica. Este primer estudio reveló que estas células madre parecían estar promoviendo la regeneración endometrial mediante la creación de un escenario inmunomodulador (sub-expresión del gen CXCL8), que daría paso a la sobreexpresión de genes involucrados en la regeneración tisular, como SERPINE1, IL4, y JUN. Otro tratamiento que ha ido ganando acepción con los años es el plasma rico en plaquetas, eje central del manuscrito 2. Este manuscrito evidencia como este plasma, especialmente si proviene de sangre de cordón umbilical, es capaz de promover procesos celulares, como la migración y la proliferación de las células endometriales, así como eventos regenerativos en un modelo animal con daño endometrial inducido. Sea cual sea la aproximación terapéutica de elección, se ha hipotetizado que esta regeneración tisular podría surgir de la estimulación del nicho de células madre presente en el endometrio. Es por ello que el objetivo 3 supuso el estudio de los trabajos publicados, tanto de modelos murinos como humanos, relativos a esta población de células madre endometriales. Esta búsqueda permitió concluir que aún quedan lagunas de conocimiento, bien sea en la definición de marcadores celulares específicos o en de la contribución de la médula ósea a este nicho de células madre endometriales. Finalmente, dada la mencionada falta actual de una terapia definitiva para las pacientes con atrofia endometrial o síndrome de Asherman, el cuarto y último objetivo de esta tesis supuso el estudio de todas aquellas aproximaciones que se han llevado a cabo en modelos animales que simulan este tipo de patologías humanas. Este trabajo concluyó que si bien están emergiendo nuevas terapias muy prometedoras, como son aquellas derivadas de la bioingeniería (por ejemplo, uso de hidrogeles o biomoldes), todavía falta perfeccionar y estandarizar los modelos tanto animales como in vitro que permitan una mejor traslación clínica de las mismas.The uterus is one of the main internal organs of the female reproductive system. It is composed of three different tissue layers: perimetrium, myometrium, and endometrium. This last layer covers the intrauterine cavity and is directly responsible for embryo implantation (for which it needs a certain minimum endometrial thickness). Among the pathologies affecting the endometrium, we can distinguish, among others, endometrial atrophy (characterized by an insufficient endometrial thickness) and Asherman's syndrome (a rare disease characterized by the presence of intrauterine adhesions and fibrotic tissue), which form the common thread of this thesis, composed of four original manuscripts. In both cases, the endometrial tissue is degenerated, which hinders the correct embryo implantation, causing then fertility problems. To date, none of these pathologies has a totally effective cure. So far, one of the most promising therapeutic options is the injection of stem cells. Therefore, the first objective was to evaluate how the infusion of bone marrow-derived stem cells (isolated with the antigen CD133), which had proven effective in both a human and an animal model, was modifying the endometrium at the molecular level. Then, this work aimed to understand the paracrine mechanisms through which these cells were carrying out their therapeutic and regenerative action over the endometrial tissue. This first study revealed that these stem cells appeared to be promoting endometrial regeneration by creating an immunomodulatory scenario (down-regulation of the CXCL8 gene), which would give way to the over-expression of genes (SERPINE1, IL4, and JUN) involved in tissue regeneration. Another treatment gaining acceptance over the years is a blood derivate, platelet-rich plasma, which was the focus of the second manuscript. This work shows how this plasma, mainly derived from umbilical cord blood rather than adult peripheral blood, can promote cellular processes, such as cell migration and proliferation of different types of endometrial cells (from primary culture and from stem cell lines). These plasmas also revealed how they triggered the over-expression of certain proteins involved in regenerative events in a mouse model with induced endometrial damage. Whatever the therapeutic approach of choice, it has been hypothesized that regeneration could arise from stimulation of the stem cell niche present in the endometrium. That is why objective three involved studying those works, both murine and human models, concerning this population of endometrial stem cells. This search concluded that there are still gaps in knowledge, either in the definition of specific endometrial stem cell markers or in the contribution of the bone marrow to this endogenous endometrial stem cell niche. Finally, given the aforementioned current lack of definitive therapy for patients with endometrial atrophy or Asherman's syndrome, the last objective involved studying all those approaches that have been carried out in animal models that simulate this type of human pathology. This work concluded that although new therapies are emerging, such as those derived from bioengineering (e.g. use of decellularized scaffolds or hydrogels), there is still a need to perfect and standardize both animal and in vitro models to allow a better clinical translation of these therapies

    Adaptive task selection using threshold-based techniques in dynamic sensor networks

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    Sensor nodes, like many social insect species, exist in harsh environments in large groups, yet possess very limited amount of resources. Lasting for as long as possible, and fulfilling the network purposes are the ultimate goals of sensor networks. However, these goals are inherently contradictory. Nature can be a great source of inspiration for mankind to find methods to achieve both extended survival, and effective operation. This work aims at applying the threshold-based action selection mechanisms inspired from insect societies to perform action selection within sensor nodes. The effect of this micro-model on the macro-behaviour of the network is studied in terms of durability and task performance quality. Generally, this is an example of using bio-inspiration to achieve adaptivity in sensor networks
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