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- Identifying an effective mobile health application for the self-management of allergic rhinitis and asthma in AustraliaPublication . Tan, Rachel; Cvetkovski, Biljana; Koshelev, Alexey; O'Hehir, Robyn; Lourenço, Olga; Bousquet, Jean; Bosnic-Anticevich, SinthiaObjective: People with allergic rhinitis (AR) often self-manage in the community pharmacy setting without consulting health care professionals and trivialize their comorbidities such as asthma. A mobile health application (mHealth app) with a self-monitoring and medication adherence system can assist with the appropriate self-management of AR and asthma. This study aimed to identify an app effective for the self-management of AR and/or asthma. Methods: MHealth apps retrieved from the Australian Apple App Store and Android Google Play Store were included in this study if they were developed for self-management of AR and/or asthma; in English language; free of charge for the full version; and accessible to users of the mHealth app. The mHealth app quality was evaluated on three domains using a two-stage process. In Stage 1, the apps were ranked along Domain 1 (Accessibility in both app stores). In Stage 2, the apps with Stage 1, maximum score were ranked along Domain 2 (alignment with theoretical principles of the self-management of AR and/or asthma) and Domain 3 (usability of the mHealth app using Mobile App Rating Scale instrument). Results: Of the 418 apps retrieved, 31 were evaluated in Stage 1 and 16 in Stage 2. The MASK-air achieved the highest mean rank and covered all self-management principles except the doctor's appointment reminder and scored a total MARS mean score of 0.91/1. Conclusions:MASK-air is ranked most highly across the assessment domains for the self-management of both AR and coexisting asthma. This mHealth app covers the majority of the self-management principles and is highly engaging.
- Towards conformally flat, non-Kasner vacuum solution in infinite derivative gravityPublication . Koshelev, Alexey; Marto, João; Mazumdar, AnupamIn this paper, we will show that the equations of motion of the quadratic in curvature, ghost free, infinite derivative theory of gravity will not permit an anisotropic collapse of a homogeneous Universe such as Kasner-type vacuum solution. However, such a solution is shown to be admissible in the local quadratic curvature gravity. Therefore pointing towards the crucial role played by the non-local infinite derivatives. We will show that it is possible to obtain conformally flat and singularity-free spacetime metrics.
- Effective models of inflation from a non-local frameworkPublication . Koshelev, Alexey; Kumar, K. Sravan; Moniz, PauloThe dilaton is a possible inflaton candidate following recent CMB data allowing a non-minimal coupling to the Ricci curvature scalar in the early Universe. In this paper, we introduce an approach that has seldom been used in the literature, namely dilaton inflation with non-local features. More concretely, employing non-local features expressed in J. High Energy Phys. 04 (2007) 029, we study quadratic variations around a de Sitter geometry of an effective action with a non-local dilaton. The non-locality refers to an infinite derivative kinetic term involving the operator $\mathcal{F}\left(\Box\right)$. Algebraic roots of the characteristic equation $\mathcal{F}(z)=0$ play a crucial role in determining the properties of the theory. We subsequently study the cases when $\mathcal{F}\left(\Box\right)$ has one real root and one complex root, from which we retrieve two concrete effective models of inflation. In the first case we retrieve a class of single field inflations with universal prediction of $n_{s}\sim0.967$ with any value of the tensor to scalar ratio $r<0.1$ intrinsically controlled by the root of the characteristic equation. The second case involves a new class of two field conformally invariant models with a peculiar quadratic cross-product of scalar fields. In this latter case, we obtain Starobinsky like inflation through a spontaneously broken conformal invariance. Furthermore, an uplifted minimum of the potential, which accounts for the vacuum energy after inflation is produced naturally through this mechanism intrinsically within our approach.
- Conformally-flat, non-singular static metric in infinite derivative gravityPublication . Buoninfante, Luca; Koshelev, Alexey; Lambiase, Gaetano; Marto, João; Mazumdar, AnupamIn Einstein's theory of general relativity the vacuum solution yields a blackhole with a curvature singularity, where there exists a point-like source with a Dirac delta distribution which is introduced as a boundary condition in the static case. It has been known for a while that ghost-free infinite derivative theory of gravity can ameliorate such a singularity at least at the level of linear perturbation around the Minkowski background. In this paper, we will show that the Schwarzschild metric does not satisfy the boundary condition at the origin within in nite derivative theory of gravity, since a Dirac delta source is smeared out by non-local gravitational interaction. We will also show that the spacetime metric becomes conformally-flat and singularity-free within the non-local region, which can be also made devoid of an event horizon. Furthermore, the scale of non-locality ought to be as large as that of the Schwarzschild radius, in such a way that the gravitational potential in any metric has to be always bounded by one, implying that gravity remains weak from the infrared all the way up to the ultraviolet regime, in concurrence with the results obtained in [arXiv:1707.00273]. The singular Schwarzschild blackhole can now be potentially replaced by a non-singular compact object, whose core is governed by the mass and the e efective scale of non-locality.
- Non-singular rotating metric in ghost-free infinite derivative gravityPublication . Buoninfante, Luca; Cornell, Alan; Harmsen, Gerhard; Koshelev, Alexey; Lambiase, Gaetano; Marto, João; Mazumdar, AnupamIt is well-known that the vacuum solution of Einstein's theory of general relativity provides a rotating metric with a ring singularity, which is covered by the inner and outer horizons, and an ergo region. In this paper, we will discuss how ghost free, quadratic curvature, Infinite Derivative Gravity (IDG) may resolve the ring-type singularity in nature. It is well-known that a class of IDG actions admit linearized metric solutions which can avoid point-like singularity by a smearing process of the Delta-source distribution induced by non-locality, which makes the metric potential finite everywhere including at $r=0$, and even at the non-linear level may resolve the Schwarzschild singularity. The same action can also resolve the ring singularity in such a way that no horizons are formed in the linear regime, where in this case non-locality plays a crucial role in smearing out a delta-source distribution on a ring. We will also study the full non-linear regime. First, we will argue that the presence of non-local gravitational interaction will not allow the Kerr metric as an exact solution, as there are infinite order derivatives acting on the theta-Heaviside and the delta-Dirac distributions on a ring. Second, we will explicitly show that the Kerr-metric is not a pure vacuum solution when the Weyl squared term, with a non-constant form-factor, is taken into account in the action.
- Schwarzschild 1/r-singularity is not permissible in ghost free quadratic curvature infinite derivative gravityPublication . Koshelev, Alexey; Marto, João; Mazumdar, AnupamIn this paper we will study the complete equations of motion for a ghost free quadratic curvature infinite derivative gravity. We will argue that within the scale of non-locality, Schwarzschild-type singular metric solution is not permissible. Therefore, Schwarzschild-type vacuum solution which is a prediction in Einstein-Hilbert gravity may not persist within the region of non-locality. We will also show that just quadratic curvature gravity, without infinite derivatives, always allows Schwarzschild-type singular metric solution.