441 research outputs found

    An Exact Solution for Static Scalar Fields Coupled to Gravity in (2+1)(2+1)-Dimensions

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    We obtain an exact solution for the Einstein's equations with cosmological constant coupled to a scalar, static particle in static, "spherically" symmetric background in 2+1 dimensions.Comment: 9 pages. Replaced by a revised versio

    Energy optimization of a light projection system for buildings that virtually restores artworks

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    Published March 2022: Erratum regarding missing Declaration of Competing Interest statements in previously published articles - Part 1 (Digital Applications in Archaeology and Cultural Heritage, Volume 24, March 2022, Pages e00209). DOI: https://doi.org/10.1016/j.daach.2021.e00209; Erratum incluido en el documentoThe need to achieve energy efficiency standards in the lighting systems of buildings makes it necessary to optimize all aspects of them. Here, the development of a light projection system that achieves this goal by studyingand modifying the spectral output, compared to conventional illumination, is described. A lighting system thatestimates the reflectance characteristics of artwork and emits optimized lighting can reduce light absorption. Adamage-minimizing point-by-point light projection system is developed using an optimization algorithm, toimprove the appearance of the surfaces of artworks whose color has faded. In this case, a simulation of an aged oilpainting was made by manipulating the original photograph, which was printed and to which the proposedsystem was applied. The results show that, when the aged printed image is illuminated with the optimized lightsource, it appears indistinguishable from the non-aged oil painting.This research was supported by project RTI2018-097633-A-I00 from the Spanish Ministry funding "Proyectos I + D Retos de Investigación" entitled Photonic restoration applied to cultural heritage: application to Dali's picture "Dos Figuras

    Constraining Bosonic Supersymmetry from Higgs results and 8 TeV ATLAS multi-jets plus missing energy data

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    The collider phenomenology of models with Universal Extra Dimensions (UED) is surprisingly similar to that of supersymmetric (SUSY) scenarios. For each level-1 bosonic (fermionic) Kaluza-Klein (KK) state, there is a fermionic (bosonic) analog in SUSY and thus UED scenarios are often known as bosonic supersymmetry. The minimal version of UED (mUED) gives rise to a quasi-degenerate particle spectrum at each KK-level and thus, can not explain the enhanced Higgs to diphoton decay rate hinted by the ATLAS collaboration of the Large Hadron Collider (LHC) experiment. However, in the non-minimal version of the UED (nmUED) model, the enhanced Higgs to diphoton decay rate can be easily explained via the suitable choice of boundary localized kinetic (BLK) terms for higher dimensional fermions and gauge bosons. BLK terms remove the degeneracy in the KK mass spectrum and thus, pair production of level-1 quarks and gluons at the LHC gives rise to hard jets, leptons and large missing energy in the final state. These final states are studied in details by the ATLAS and CMS collaborations in the context of SUSY scenarios. We find that the absence of any significant deviation of the data from the Standard Model (SM) prediction puts a lower bound of about 2.1 TeV on equal mass excited quarks and gluons.Comment: 19 page

    Energy optimization of a light projection system for buildings that virtually restores artworks

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    The need to achieve energy efficiency standards in the lighting systems of buildings makes it necessary to optimize all aspects of them. Here, the development of a light projection system that achieves this goal by studying and modifying the spectral output, compared to conventional illumination, is described. A lighting system that estimates the reflectance characteristics of artwork and emits optimized lighting can reduce light absorption. A damage-minimizing point-by-point light projection system is developed using an optimization algorithm, to improve the appearance of the surfaces of artworks whose color has faded. In this case, a simulation of an aged oil painting was made by manipulating the original photograph, which was printed and to which the proposed system was applied. The results show that, when the aged printed image is illuminated with the optimized light source, it appears indistinguishable from the non-aged oil painting

    The effect of continuous ultrasound on chronic low back pain: protocol of a randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Chronic non-specific low-back pain (LBP) is one of the most common and expensive musculoskeletal disorders in industrialized countries. Similar to other countries in the world, LBP is a common health and socioeconomic problem in Iran. One of the most widely used modalities in the field of physiotherapy for treating LBP is therapeutic ultrasound. Despite its common use, there is still inconclusive evidence to support its effectiveness in this group of patients. This randomised trial will evaluate the effectiveness of continuous ultrasound in addition to exercise therapy in patients with chronic LBP.</p> <p>Methods and design</p> <p>A total of 46 patients, between the ages 18 and 65 years old who have had LBP for more than three months will be recruited from university hospitals. Participants will be randomized to receive continuous ultrasound plus exercise therapy or placebo ultrasound plus exercise therapy. These groups will be treated for 10 sessions during a period of 4 weeks. Primary outcome measures will be functional disability and pain intensity. Lumbar flexion and extension range of motion, as well as changes in electromyography muscle fatigue indices, will be measured as secondary outcomes. All outcome measures will be measured at baseline, after completion of the treatment sessions, and after one month.</p> <p>Discussion</p> <p>The results of this trial will help to provide some evidence regarding the use of continuous ultrasound in chronic LBP patients. This should lead to a more evidence-based approach to clinical decision making regarding the use of ultrasound for LBP.</p> <p>Trial registration</p> <p>Netherlands Trial Register (NTR): <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2251">NTR2251</a></p
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