5,114 research outputs found

    The GraviGUT Algebra Is not a Subalgebra of E8E_8, but E8E_8 Does Contain an Extended GraviGUT Algebra

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    The (real) GraviGUT algebra is an extension of the spin(11,3)\mathfrak{spin}(11,3) algebra by a 6464-dimensional Lie algebra, but there is some ambiguity in the literature about its definition. Recently, Lisi constructed an embedding of the GraviGUT algebra into the quaternionic real form of E8E_8. We clarify the definition, showing that there is only one possibility, and then prove that the GraviGUT algebra cannot be embedded into any real form of E8E_8. We then modify Lisi's construction to create true Lie algebra embeddings of the extended GraviGUT algebra into E8E_8. We classify these embeddings up to inner automorphism

    Discrimination, Lending Practices and Housing Values: Preliminary Evidence from the Houston Market

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    At the center of the debate on racially induced price differentials in housing is the issue of discrimination. This research studies the impact that ethnic as well as racial composition in a neighborhood exerts on value. In an attempt to extend previous efforts, aggregate data is used to study the effects of discrimination and lending bias on residential real estate in Houston, Texas. The data do not support allegations of systematic bias in the mortgage lending process.

    What Are The Implications of The Global Crisis and its Aftermath for Developing Countries, 2010-2020?

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    Some major ?game changers? beyond the recent economic crisis and food/fuel crisis will have an impact on the Millennium Development Goals (MDGs) to 2015 and afterwards. ?Future-proofing? the MDGs is about thinking how future(s) might impact the Goals, MDG gains, costs, strategies and opportunities for faster progress on poverty reduction. Scenarios?multiple coherent and plausible futures?are a vehicle both for acting on possible future(s) and interpreting their implications. This paper explores the implications for growth and poverty reduction in developing countries of four futures scenarios to address the following question: ?What are the implications of the global financial crisis and its aftermath, regionally and globally, for developing countries, taking a 5?10 year view? The scenarios and modelling were developed through interviews and workshops with a range of stakeholders in the United Kingdom, India and Kenya. This paper takes a structured approach to reviewing outcomes for growth, poverty reduction and the MDGs for different developing economies, against the background of the post-crisis context. The scenarios were developed using a version of the morphological scenarios approach, field anomaly relaxation (FAR). This creates a backdrop of internally consistent futures for policy formation and decision making by identifying and analysing the most significant drivers of change in the global financial and political systems. The scenarios are closely connected to a ?soft? model that identifies possible pathways, causal linkages and transmission variables between the scenarios and associated levels of economic growth and poverty reduction via key economic variables. This permits more granular interpretation of the scenario outcomes than conventional scenario-analysis techniques. The work was financed by Britain?s Department for International Development (DFID). (...)What Are The Implications of The Global Crisis and its Aftermath for Developing Countries, 2010-2020?

    A multi-paradigm, whole system view of health and social care for age-related macular degeneration

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    The progenitors of calcium-rich transients are not formed in situ

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    We present deep VLT and HST observations of the nearest examples of calcium-rich 'gap' transients -- rapidly evolving transient events, with a luminosity intermediate between novae and supernovae. These sources are frequently found at large galactocentric offsets, and their progenitors remain mysterious. Our observations find no convincing underlying quiescent sources coincident with the locations of these transients, allowing us to rule out a number of potential progenitor systems. The presence of surviving massive-star binary companions (or other cluster members) are ruled out, providing an independent rejection of a massive star origin for these events. Dwarf satellite galaxies are disfavoured unless one invokes as yet unknown conditions that would be extremely favourable for their production in the lowest mass systems. Our limits also probe the majority of the globular cluster luminosity function, ruling out the presence of an underlying globular cluster population at high significance, and thus the possibility that they are created via dynamical interactions in dense globular cluster cores. Given the lack of underlying systems, previous progenitor suggestions have difficulty reproducing the remote locations of these transients, even when considering solely halo-borne progenitors. Our preferred scenario is that calcium-rich transients are high velocity, kicked systems, exploding at large distances from their natal site. Coupled with a long-lived progenitor system post-kick, this naturally explains the lack of association these transients have with their host stellar light, and the extreme host-offsets exhibited. Neutron star -- white dwarf mergers may be a promising progenitor system in this scenario.Comment: Accepted for publication in MNRAS, 11 pages, 9 figure

    A contra-rotating marine current turbine on a flexible mooring : development of a scaled prototype

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    The contra-rotating marine current turbine concept developed by the Energy Systems Research Unit at the University of Strathclyde is aimed at extracting energy in a wide range of water depths by 'flying' a neutrally-buoyant device from a flexible, tensioned mooring. After successful proof of concept turbine trials, the development programme has moved on to investigate the performance of a scaled prototype of the complete system incorporating the turbine, submersible contra-rotating generator and mooring. The turbine/generator assembly has been tested in a towing tank, and the entire system is now undergoing sea trials. An investigation into turbine wake development (an area in which it is hoped that the contra-rotating turbine will have uniquely beneficial properties) has recently begun. Small single-rotor model turbines have been deployed in a flume. Trends observed so far are in accordance with those observed by other researchers
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