Searching for a Cosmological Preferred Axis in complicated class of cosmological models:Case study f(R,T)f(R,T) model

Recent astronomical observations show that the universe may be anisotropic on large scales. The Union2 SnIa data hint that the universe has a preferred direction. If such a cosmological privileged axis indeed exists, one has to consider an anisotropic expanding Universe instead of the isotropic cosmological model. In this paper, we present a detailed analysis of the dark energy dipole in $f(R,T)=f_{1}(R)+f_{2}(T)$ Cosmological Model using three types of dipole fit (DF) method which are (I)dipole + monopole fitting for distance modulus(DMFDM), (II)dipole + monopole fitting for luminosity distance(DMFLD) and (III) general dipole fitting for luminosity distance(GDFLD). We have found the maximum anisotropic deviation direction for (DMFDM) method as $(l, b)=(315^{+25}_{-25},-23^{+14}_{-15})$, for (DMFLD) as $(l, b)=(l, b)=(315^{+35}_{-37},-23^{+18}_{-18})$, and for (GDFLD) method as $(l, b)=(317^{+32}_{-32},-23^{+18}_{-18})$ which are located very close to each other. We compare our model with the $CPL$, $\Lambda CDM$ and $\omega CDM$ models. Constraints on $(l, b)$ in $f(R, T)$ model are not much different from the cases of the $CPL$, $\Lambda CDM$ and $\omega CDM$ models. Moreover, the results are consistent with other studies.Comment: 40 page 25 fig. arXiv admin note: text overlap with arXiv:1303.0961, arXiv:1302.1866, arXiv:1411.1466, arXiv:1107.5807, arXiv:1306.3164 by other author

Mechanism for a Decaying Cosmological Constant

A mechanism is introduced to reduce a large cosmological constant to a sufficiently small value consistent with observational upper limit. The basic ingradient in this mechanism is a distinction which has been made between the two unit systems used on cosmology and particle physics. We have used a conformal invariant gravitational model to define a particular conformal frame in terms of the large scale properties of the universe. It is then argued that the contributions of mass scales in particle physics to the vacuum energy density should be considered in a different conformal frame. In this manner a cancellation mechanism is presented in which the conformal factor plays a key role to relax the large effective cosmological constant.Comment: 6 pages, no figur

Measuring the burden of treatment for chronic disease: implications of a scoping review of the literature

Background: Although there has been growing research on the burden of treatment, the current state of evidence on measuring this concept is unknown. This scoping review aimed to provide an overview of the current state of knowledge as well as clear recommendations for future research, within the context of chronic disease. Methods: Four health-based databases, Scopus, CINAHL, Medline, and PsychInfo, were comprehensively searched for peer-reviewed articles published between the periods of 2000–2016. Titles and abstracts were independently read by two authors. All discrepancies between the authors were resolved by a third author. Data was extracted using a standardized proforma and a comparison analysis was used in order to explore the key treatment burden measures and categorize them into three groups. Results: Database searching identified 1458 potential papers. After removal of duplications, and irrelevant articles by title, 1102 abstracts remained. An additional 22 papers were added via snowball searching. In the end, 101 full papers were included in the review. A large number of the studies involved quantitative measures and conceptualizations of treatment burden (n = 64; 63.4%), and were conducted in North America (n = 49; 48.5%). There was significant variation in how the treatment burden experienced by those with chronic disease was operationalized and measured. Conclusion: Despite significant work, there is still much ground to cover to comprehensively measure treatment burden for chronic disease. Greater qualitative focus, more research with cultural and minority populations, a larger emphasis on longitudinal studies and the consideration of the potential effects of “identity” on treatment burden, should be considered

The Effect of the Circumstellar Material on the Light Curves of Eclipsing Binary Systems

This study inspects the influence of various effects and free parameters of the accretion disc and circumstellar material on the emerging light curve of eclipsing binary systems that have a circumstellar disc, by using the SHELLSPEC code. The results indicate that some of the parameters namely the temperature and inclination of the disc, spot, jet, stream and shell significantly affect on the emerging light curve while some other parameters namely the exponent of the power-law behavior of the density of the disc, microturbulence, inner and outer radius of the disc don't noticeably affect on the emerging light curve. An application to the Algol-type eclipsing binary system AV Del and an accretion disc model for the system using the SHELLSPEC code is included.Comment: was accepted for publication in PASA. arXiv admin note: substantial text overlap with arXiv:astro-ph/0501108 (by different authors

Hadamard States and Two-dimensional Gravity

We have used a two-dimensional analog of the Hadamard state-condition to study the local constraints on the two-point function of a linear quantum field conformally coupled to a two-dimensional gravitational background. We develop a dynamical model in which the determination of the state of the quantum field is essentially related to the determination of a conformal frame. A particular conformal frame is then introduced in which a two-dimensional gravitational equation is established.Comment: 7 pages, no figur

Incorporating Betweenness Centrality in Compressive Sensing for Congestion Detection

This paper presents a new Compressive Sensing (CS) scheme for detecting network congested links. We focus on decreasing the required number of measurements to detect all congested links in the context of network tomography. We have expanded the LASSO objective function by adding a new term corresponding to the prior knowledge based on the relationship between the congested links and the corresponding link Betweenness Centrality (BC). The accuracy of the proposed model is verified by simulations on two real datasets. The results demonstrate that our model outperformed the state-of-the-art CS based method with significant improvements in terms of F-Score

Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator

Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here we lower the chemical potential of three-dimensional (3D) Bi$_2$Se$_3$ films to $\sim$ 30 meV above the Dirac point, and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 T, we observed quantized Faraday and Kerr rotations, whereas the DC transport is still semi-classical. A non-trivial Berry phase offset to these values gives evidence for axion electrodynamics and the topological magnetoelectric effect. The time structure used in these measurements allows a direct measure of the fine structure constant based on a topological invariant of a solid-state system.Comment: A shortened version has been published in Science. Discussion on AC quantum Hall effect without involving edge states is adde