381 research outputs found

    Weak field and slow motion limits in energy-momentum powered gravity

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    We explore the weak field and slow motion limits, Newtonian and Post-Newtonian limits, of the energy-momentum powered gravity (EMPG), viz., the energy-momentum squared gravity (EMSG) of the form f(TμνTμν)=α(TμνTμν)ηf(T_{\mu\nu}T^{\mu\nu})=\alpha (T_{\mu\nu}T^{\mu\nu})^{\eta} with α\alpha and η\eta being constants. We have shown that EMPG with η0\eta\geq0 and general relativity (GR) are not distinguishable by local tests, say, the Solar System tests; as they lead to the same gravitational potential form, PPN parameters, and geodesics for the test particles. However, within the EMPG framework, MastM_{\rm ast}, the mass of an astrophysical object inferred from astronomical observations such as planetary orbits and deflection of light, corresponds to the effective mass Meff(α,η,M)=M+Mempg(α,η,M)M_{\rm eff}(\alpha,\eta,M)=M+M_{\rm empg}(\alpha,\eta,M), MM being the actual physical mass and MempgM_{\rm empg} being the modification due to EMPG. Accordingly, while in GR we simply have the relation Mast=MM_{\rm ast}=M, in EMPG we have Mast=M+MempgM_{\rm ast}=M+M_{\rm empg}. Within the framework of EMPG, if there is information about the values of {α,η}\{\alpha,\eta\} pair or MM from other independent phenomena (from cosmological observations, structure of the astrophysical object, etc.), then in principle it is possible to infer not only MastM_{\rm ast} alone from astronomical observations, but MM and MempgM_{\rm empg} separately. For a proper analysis within EMPG framework, it is necessary to describe the slow motion condition (also related to the Newtonian limit approximation) by peff/ρeff1|p_{\rm eff}/\rho_{\rm eff}|\ll1 (where peff=p+pempgp_{\rm eff}=p+p_{\rm empg} and ρeff=ρ+ρempg\rho_{\rm eff}=\rho+\rho_{\rm empg}), whereas this condition leads to p/ρ1|p/\rho|\ll1 in GR.Comment: 12 pages, no figures and table

    Innovation and opportunity: review of the UK’s national AI strategy

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    The publication of the UK’s National Artificial Intelligence (AI) Strategy represents a step-change in the national industrial, policy, regulatory, and geo-strategic agenda. Although there is a multiplicity of threads to explore this text can be read primarily as a ‘signalling’ document. Indeed, we read the National AI Strategy as a vision for innovation and opportunity, underpinned by a trust framework that has innovation and opportunity at the forefront. We provide an overview of the structure of the document and offer an emphasised commentary on various standouts. Our main takeaways are: Innovation First: a clear signal is that innovation is at the forefront of UK’s data priorities. Alternative Ecosystem of Trust: the UK’s regulatory-market norms becoming the preferred ecosystem is dependent upon the regulatory system and delivery frameworks required. Defence, Security and Risk: security and risk are discussed in terms of utilisation of AI and governance. Revision of Data Protection: the signal is that the UK is indeed seeking to position itself as less stringent regarding data protection and necessary documentation. EU Disalignment—Atlanticism?: questions are raised regarding a step back in terms of data protection rights. We conclude with further notes on data flow continuity, the feasibility of a sector approach to regulation, legal liability, and the lack of a method of engagement for stakeholders. Whilst the strategy sends important signals for innovation, achieving ethical innovation is a harder challenge and will require a carefully evolved framework built with appropriate expertise

    Imaging characteristics and treatment of a penetrating brain injury caused by an oropharyngeal foreign body in a dog

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    A 4-year-old Border collie was presented with one episode of collapse, altered mentation, and a suspected pharyngeal stick injury. Magnetic resonance imaging (MRI) and computed tomography showed a linear foreign body penetrating the right oropharynx, through the foramen ovale and the brain parenchyma. The foreign body was surgically removed and medical treatment initiated. Complete resolution of clinical signs was noted at recheck 8 weeks later. Repeat MRI showed chronic secondary changes in the brain parenchyma. To the authors' knowledge, this is the first report of the advanced imaging findings and successful treatment of a penetrating oropharyngeal intracranial foreign body in a dog

    Prototype modeling of security system with metal detector

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    The security system provides the ease to people in order to manage their mall easier and this system is concern on the security of each item. This system will provide not only the items identification but also the anti-theft security. Nowadays, each items produced have a barcode that is printed on its surface as product code. The old system seems not to fully utilize the barcode on each item. This system combines the barcode with electromagnetic security strips in order to reduce the security cost. The barcode strip will be developed in two layers, the barcode and the magnetic strip. The system is working such as the customers self service in the library. The items need to be check at the counter before it been taking out from the store. If the item is not registered then, the alarm will give a warning when it passes through the electromagnetic gate. The LabVIEW program developed by National Instrument is found out to be the best selection as the wave recognition to this system. Identification of patrons and materials by barcode is a reliable technique and gave great service when combined with electro-magnetic security device

    Refurbishment of public housing villas in the United Arab Emirates (UAE): energy and economic impact

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    © 2016, Springer Science+Business Media Dordrecht. This study aims at assessing the technical and economic benefits of refurbishing existing public housing villas in the UAE. Four representative federal public housing villas built between 1980s and 2010s were modeled and analyzed. The Integrated Environmental Solutions-Virtual Environment (IES-VE) energy modeling software was used to estimate the energy consumption and savings due to different refurbishment configurations applied to the villas. The refurbishment technical configurations were based on the UAE’s Estidama green buildings sustainability assessment system. The refurbishment configurations include upgrading three elements: the wall and roof insulation as well as replacing the glazing. The annual electricity savings results indicated that the most cost-efficient refurbishment strategy is upgrading of wall insulation (savings up to 20.8 %) followed by upgrading the roof’s insulation (savings up to 11.6 %) and lastly replacing the glazing (savings up to 3.2 %). When all three elements were refurbished simultaneously, savings up to 36.7 % were achieved (villa model 670). The savings translated to CO2 emission reduction of 22.6 t/year. The simple and discounted payback periods for the different configurations tested ranged between 8 and 28 and 10 and 50 years, respectively

    Effectiveness of Meningococcal B Vaccine against Endemic Hypervirulent Neisseria meningitidis W Strain, England

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    Serum samples from children immunized with a meningococcal serogroup B vaccine demonstrated potent serum bactericidal antibody activity against the hypervirulent Neisseria meningitidis serogroup W strain circulating in England. The recent introduction of this vaccine into the United Kingdom national immunization program should also help protect infants against this endemic strain

    Application of large datasets to assess trends in the stability of perovskite photovoltaics through machine learning

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    Current trends in manufacturing indicate that optimised decision making using new state-of-the-art machine learning (ML) technologies will be used. ML is a versatile technique that rapidly and accurately generates new insights from multifactorial data. The ML approach has been applied to a perovskite solar cell (PSC) database to elucidate trends in stability and forecast the stability of new configurations. A database consisting of 6038 entries of device characteristics, performance, and stability data was utilised, and a sequential minimal optimisation regression (SMOreg) model was employed to determine the most influential factors governing solar cell stability. When considering sub-sections of data, it was found that pin-device architectures provided the best model fittings with a training correlation efficiency of 0.963, compared to 0.699 for all device architectures. By establishing models for each PSC architecture, the analysis allows the identification of materials that can lead to improvements in stability. This paper also attempts to summarise some key challenges and trends in the current research methodologies
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