22282 research outputs found
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Searching for New High Mass Resonances in the Dielectron Channel, using the ATLAS Detector at CERN
No full textA search is conducted in the dielectron channel for beyond the Standard Model high mass neutral resonances, such as E6 motivated Z′ states and the Randall-Sundrum Graviton. The data in this thesis was recorded by the ATLAS detector during proton-proton collisions in 2011 at √s = 7 TeV, provided by the Large Hadron Collider at CERN in Geneva, Switzerland. The dataset used constitutes a total integrated luminosity of 2.12 fb−1 after data quality checks. The dielectron channel result is presented and combined with the equivalent 1.21 fb−1 dimuon channel result for the Z′. Additionally these results are combined with the 2.12 fb−1 diphoton channel result for the RS Graviton. The greatest excess in the dielectron channel is observed at 580 GeV with a significance of 1.34 σ. Therefore as no significant excess is observed in data above the Standard Model expectation, exclu- sion limits are set at 95% confidence level on the cross section times branching ratio for various signal scenarios as a function of resonance mass. A combined lower mass limit of 1.96 TeV is set on the ZS′ SM, and 1.95 TeV for a Randall-Sundrum Graviton with k/MPl = 0.10. These limits represent the world’s highest observed mass exclusion for the models considered, at the time of writing this thesis
On the effects of large-scale transcriptomics datasets on gene functional analyses
No full textThe Guilt-by-Association (GBA) principle, according to which genes with similar expression profiles are functionally associated, is widely applied for functional analyses using large heterogeneous collections of transcriptomics data. In this thesis we show that using such large collections could hamper GBA functional analysis for genes whose expression is condition specific. In these cases a smaller set of condition related experiments should instead be used, but identifying such functionally relevant experiments from large collections based on literature knowledge alone is an impractical task. The study begins by discussing the basic principles underlying the definition of gene function and the use of large microarray collections for GBA based gene function analyses. We look at the effects of condition specific gene expression on GBA analyses and provide a mathematical and biological perspective. We show that using large microarray collections to calculate correlation can mask the effectiveness of the GBA principle. We suggest that using only those experiments that are relevant to the biological function under analysis can significantly improve GBA based gene functional analyses. We then present a semi-supervised algorithm that can select functionally relevant experiments from large collections of transcriptomics experiments. The algorithm is able to select experiments relevant to a given GO term, MIPS FunCat term or even KEGG pathways. We extensively test our algorithm on large dataset collections for Yeast and Arabidopsis. We demonstrate that: (i) using the selected experiments there is a statistically significant improvement both in correlation between genes in the functional category of interest and in GBA based function predictions; (ii) the effectiveness of the selected experiments increases with annotation specificity; (iii) our algorithm can be successfully applied to GBA based pathway reconstruction. We conclude by discussing the potential applications of our technique. We outline several developments that could be implemented in the future to improve the efficiency of the experiment selection procedure
Designing and experiencing sensory urban environments: An intensive case study of Grand Union Village in West London
No full textInvestigating the role of the urban village within ‘neo-traditional’ urbanism, existing studies focus on flagship projects such as Poundbury. By contrast, this thesis explores the under-researched everyday and mainstream developments undertaken by volume house builders. These developments are not associated with a philanthropic disregard for profit, nor are they showcases for urban theories such as the urban village movement. Through an intensive investigation of one urban village: Grand Union Village (GUV) in Ealing, West London this thesis tracks the development process from conception in 1999 to completion in 2011. It maps the compromises made along the journey resulting from conflicting relationships within the developer, volume house builder Taylor Woodrow. Utilising research drawn from unprecedented access to the development team and original Vision documents, the thesis examines the ‘macro-environmental’ elements of the Grand Union Vision, which were guided by urban village principles. The ‘micro-environment’ is examined through the design details, and textures of the built environment which informed the way a sense of place and experience were scripted into GUV. Furthermore, experiential qualities of GUV are explored through walking interviews considering the ‘after-life’ of the Village and the relationship between design and the lived reality of place. To conclude, this thesis demonstrates how the conflict between the drive for profit and desire to implement urban village principles could not be reconciled at GUV resulting in a development that is more akin to a large housing estate than an urban village. Whilst the sensory and experiential design details of GUV set it apart from normal suburban housing, such details are superficial and will diminish over time. Furthermore, within a suburban setting, the ambiguities of theorising the urban and the village prove problematic, and residents transgress and resist key urban village elements. As such wider attitudes towards suburban urban village developments need to change to allow true urban villages to be delivered
Riches from Rags or Persistent Poverty? Inequality in the Transnational Second-hand Clothing Trade in Mozambique
No full textAn ecological assessment of Impatiens glandulifera in its introduced and native range and the potential for its classical biological control
No full textOn Wanting the Moon: Avant-Garde Women and Ambition
No full textThis essay forms part of the catalogue to the exhibition 'Avant-Garde Women 1920-1940', held at the Louisiana Museum of Modern Art, Denmark, 14 February - 28 May 2012. It considers the place of ambition in the life and work of eight avant-garde women artists
Hamann, Nietzsche, and Wittgenstein on the Language of Philosophers
No full textIn this chapter I shall examine some of Johann Georg Hamann’s claims about how philosophers misuse, misunderstand, and are misled by language. I will then examine how he anticipates things that Friedrich Nietzsche and Ludwig Wittgenstein say on this topic
Multipulse Addressing of a Raman Quantum Memory: Configurable Beam Splitting and Efficient Readout
No full textQuantum memories are vital to the scalability of photonic quantum information processing (PQIP), since the storage of photons enables repeat-until-success strategies. On the other hand the key element of all PQIP architectures is the beam splitter, which allows to coherently couple optical modes. Here we show how to combine these crucial functionalities by addressing a Raman quantum memory with multiple control pulses. The result is a coherent optical storage device with an extremely large time-bandwidth product, that functions as an array of dynamically configurable beam splitters, and that can be read out with arbitrarily high efficiency. Networks of such devices would allow fully scalable PQIP, with applications in quantum computation, long-distance quantum communications and quantum metrology
A field trip through spin ice
No full textFractionalisation -- the breaking up of an apparently indivisible microscopic degree of freedom -- is one of the most counterintuitive phenomena in many-body physics. Here we study its most fundamental manifestation in spin ice, the only known fractionalised magnetic compound in 3D: we directly visualise the magnetic Coulomb field of monopoles which emerge as the atomic magnetic dipoles fractionalise. We analyse the internal magnetic field distribution, relevant for local experimental probes. In particular, we present new zero-field NMR measurements which exhibit excellent agreement with the calculated lineshapes, noting that this experimental technique can in principle measure directly the monopole density in spin ice. The distribution of field strengths is captured by a simple analytical form which exhibits a low density of low-field sites---in apparent disagreement with reported SR results. Counterintuitively, the density of low-field locations decreases as the local ferromagnetic correlations imposed by the ice rules weaken
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