30 research outputs found

    The (2+1)-dimensional charged gravastars

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    This is a continuation and generalization of our earlier work on {\it gravastar} in (2+1) anti-de Sitter space-time to 2+1 dimensional solution of charged gravastar. Morphologically this gravastar contains three regions namely: (i) charged interior, (ii) charged shell and (iii) electrovacuum exterior. We have studied different characteristics in terms of Length and Energy, Entropy, and Junction conditions of the spherical charged distribution. It is shown that the present model of charged gravastar is non-singular and represents itself an alternative of Black Hole.Comment: 14 pages, Accepted in Phys. Lett.

    Higher Dimensional Dark Energy Investigation with Variable Λ\Lambda and GG

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    Time variable Λ\Lambda and GG are studied here under a phenomenological model of Λ\Lambda through an (n+2n+2) dimensional analysis. The relation of Zeldovich (1968) Λ=8πG2mp6/h4|\Lambda| = 8\pi G^2m_p^6/h^4 between Λ\Lambda and GG is employed here, where mpm_p is the proton mass and hh is Planck's constant. In the present investigation some key issues of modern cosmology, viz. the age problem, the amount of variation of GG and the nature of expansion of the Universe have been addressed.Comment: 7 Latex pages with few change

    Bianchi Type III Anisotropic Dark Energy Models with Constant Deceleration Parameter

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    The Bianchi type III dark energy models with constant deceleration parameter are investigated. The equation of state parameter ω\omega is found to be time dependent and its existing range for this model is consistent with the recent observations of SN Ia data, SN Ia data (with CMBR anisotropy) and galaxy clustering statistics. The physical aspect of the dark energy models are discussed.Comment: 12 pages, 2 figures, Accepted version of IJT

    Stability of Non-asymptotically flat thin-shell wormholes in generalized dilaton-axion gravity

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    We construct a new type of thin-shell wormhole for non-asymptotically flat charged black holes in generalized dilaton-axion gravity inspired by low-energy string theory using cut-and-paste technique. We have shown that this thin shell wormhole is stable. The most striking feature of our model is that the total amount of exotic matter needed to support the wormhole can be reduced as desired with the suitable choice of the value of a parameter. Various other aspects of thin-shell wormhole are also analyzed.Comment: 15 pages and 11 figures. Minor revisions have been done. Accepted in Int.J.Theor.Phy

    Thin-shell wormholes from black holes with dilaton and monopole fields

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    We provide a new type of thin-shell wormhole from the black holes with dilaton and monopole fields. The dilaton and monopole that built the black holes may supply fuel to construct the wormholes. Several characteristics of this thin-shell wormhole have been discussed. Finally, we discuss the stability of the thin-shell wormholes with a "phantom-like" equation of state for the exotic matter at the throat.Comment: 6 pages and 3 figures, some typos are corrected and accepted in Int.J.Theor.Phy

    Next-generation care pathways for allergic rhinitis and asthma multimorbidity: A model for multimorbid non-communicable diseases—Meeting Report (Part 2)

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    Identification by cluster analysis of patients with asthma and nasal symptoms using the MASK-air® mHealth app

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    peer reviewedBackground: The self-reporting of asthma frequently leads to patient misidentification in epidemiological studies. Strategies combining the triangulation of data sources may help to improve the identification of people with asthma. We aimed to combine information from the self-reporting of asthma, medication use and symptoms to identify asthma patterns in the users of an mHealth app. Methods: We studied MASK-air® users who reported their daily asthma symptoms (assessed by a 0-100 visual analogue scale – “VAS Asthma”) at least three times (either in three different months or in any period). K-means cluster analysis methods were applied to identify asthma patterns based on: (i) whether the user self-reported asthma; (ii) whether the user reported asthma medication use and (iii) VAS asthma. Clusters were compared by the number of medications used, VAS asthma levels and Control of Asthma and Allergic Rhinitis Test (CARAT) levels. Findings: We assessed a total of 8,075 MASK-air® users. The main clustering approach resulted in the identification of seven groups. These groups were interpreted as probable: (i) severe/uncontrolled asthma despite treatment (11.9-16.1% of MASK-air® users); (ii) treated and partly-controlled asthma (6.3-9.7%); (iii) treated and controlled asthma (4.6-5.5%); (iv) untreated uncontrolled asthma (18.2-20.5%); (v) untreated partly-controlled asthma (10.1-10.7%); (vi) untreated controlled asthma (6.7-8.5%) and (vii) no evidence of asthma (33.0-40.2%). This classification was validated in a study of 192 patients enrolled by physicians. Interpretation: We identified seven profiles based on the probability of having asthma and on its level of control. mHealth tools are hypothesis-generating and complement classical epidemiological approaches in identifying patients with asthma. © 2022 Sociedade Portuguesa de Pneumologi
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