Emergence of world-stock-market network

In the age of globalization, it is natural that the stock market of each country is not independent form the other markets. In this case, collective behavior could be emerged form their dependency together. This article studies the collective behavior of a set of forty influential markets in the world economy with the aim of exploring a global financial structure that could be called world-stock-market network. Towards this end, we analyze the cross-correlation matrix of the indices of these forty markets using Random Matrix Theory (RMT). We find the degree of collective behavior among the markets and the share of each market in their structural formation. This finding together with the results obtained from the same calculation on four stock markets reinforce the idea of a world financial market. Finally, we draw the dendrogram of the cross-correlation matrix to make communities in this abstract global market visible. The dendrogram, drawn by at least thirty percent of correlation, shows that the world financial market comprises three communities each of which includes stock markets with geographical proximity

On functions with strongly δ-semiclosed graphs

In 1997, Park et al. [5] offered a new notion called δ-semiopen sets which are stronger than semi-open sets but weaker than δ-open sets. It is the aim of this paper to introduce and study some properties of functions with strongly δ-semiclosed graphs by utilizing δ-semiopen sets and the δ-semi-closure operator

Impact of loss on the wave dynamics in photonic waveguide lattices

We analyze the impact of loss in lattices of coupled optical waveguides and find that in such case, the hopping between adjacent waveguides is necessarily complex. This results not only in a transition of the light spreading from ballistic to diffusive, but also in a new kind of diffraction that is caused by loss dispersion. We prove our theoretical results with experimental observations.Comment: Accepted for publication in PRL, 5+8 pages (Paper + Supplemental material), 4 figure

Polypill for prevention of cardiovascular disease in an Urban Iranian population with special focus on nonalcoholic steatohepatitis: A pragmatic randomized controlled trial within a cohort (PolyIran - Liver) – Study protocol

Background: Cardiovascular disease (CVD) is among the most common causes of mortality in all populations. Nonalcoholic steatohepatitis is a common finding in patients with CVD. Prevention of CVD in individual patients typically requires periodic clinical evaluation, as well as diagnosis and management of risk factors such as hypertension and hyperlipidemia. However, this is resource consuming and hard to implement, especially in developing countries. We designed a study to investigate the effects of a simpler strategy: a fixed-dose combination pill consisting of aspirin, valsartan, atorvastatin and hydrochlorthiazide (PolyPill) in an unselected group of persons aged over 50 years. Design: The PolyIran-Liver study was performed in Gonbad city as an open label pragmatic randomized controlled trial nested within the Golestan Cohort Study. We randomly selected 2,400 cohort study participants aged above 50 years, randomly assigned them to intervention or usual care and invited them to participate in an additional measurement study (if they met the eligibility criteria) to measure liver related outcomes. Those agreeing and randomized to the intervention arm were offered a daily single dose of PolyPill. We will follow participants for 5 years. The primary outcome is major cardiovascular events, secondary outcomes include all-cause mortality and liver related outcomes: liver stiffness and liver enzyme levels. Cardiovascular outcomes and mortality will be determined from the cohort study and liver-related outcomes in those consenting to follow up. Analysis will be by allocated group. Trial Status: Between October and December 2011, 1,320 intervention and 1,080 control participants were invited to participate in the additional measurement study. For all these participants, the major cardiovascular events will be determined using blind assessment of outcomes through the cohort study. In the intervention and control arms, 875 (66%) and 721 (67%) respectively, met the eligibility criteria and agreed to participate in the additional measurement study. Liver related outcomes will be measured in these participants. Of the 1,320 participants randomized to the intervention, 787 (60%) accepted the PolyPill. Conclusion: The PolyIran-liver urban study will provide us with important information on the effectiveness of PolyPill on major cardiovascular events, all-cause mortality and liver related outcomes. (ClinicalTrials.gov ID: NCT01245608). © 2015, Academy of Medical Sciences of I.R. Iran. All rights reserved

Design and implementation of an amorphous high-frequency transformer coupling multiple converters in a smart microgrid

© 1982-2012 IEEE. Recent improvements in magnetic material characteristics and switching devices have generated a possibility to replace the electrical buses with high-frequency magnetic links in microgrids. Multiwinding transformers (MWTs) as magnetic links can effectively reduce the number of conversion stages of renewable energy system by adjusting turn ratio of windings according to the source voltage level. Other advantages are galvanic isolation, bidirectional power flow capability, and simultaneous power transfer between multiple ports. Despite the benefits, design, and characterization of MWTs are relatively complex due to their structural complexity and cross-coupling effects. This paper presents all stages of numerical design, prototyping, and characterization of an MWT for microgrid application. To design the transformer for certain value of parameters, the reluctance network method is employed. Due to the iterative nature of transformer design, it presented less computation time and reasonable accuracy. A prototype of designed transformer is implemented using amorphous magnetic materials. A set of experimental tests are conducted to measure the magnetic characteristics of the core and series coupling and open-circuit tests are applied to measure the transformer parameters. A comparison between the simulation and experimental test results under different loads within the medium-frequency range validated both design and modeling procedures

Anderson Transition in Disordered Graphene

We use the regularized kernel polynomial method (RKPM) to numerically study the effect disorder on a single layer of graphene. This accurate numerical method enables us to study very large lattices with millions of sites, and hence is almost free of finite size errors. Within this approach, both weak and strong disorder regimes are handled on the same footing. We study the tight-binding model with on-site disorder, on the honeycomb lattice. We find that in the weak disorder regime, the Dirac fermions remain extended and their velocities decrease as the disorder strength is increased. However, if the disorder is strong enough, there will be a {\em mobility edge} separating {\em localized states around the Fermi point}, from the remaining extended states. This is in contrast to the scaling theory of localization which predicts that all states are localized in two-dimensions (2D).Comment: 4 page

Progress on outbound tourism expenditure research: A review

This study aims to identify how the paradigm of outbound tourism expenditure (OTE) research transforms from economic to social concern. It also explicates the evolution of OTE from an advocacy platform to a sustainability platform. This study adopts a hybrid of narrative and systematic reviews to study OTE as a complex social phenomenon. This hybrid review is complemented by a thematic review and semantic network analysis on gaps and future directions of relevant studies. The results reveal that the paradigm of OTE research is directed from economic toward social thinking. This study proposes an application of socially related antecedent configurations, social theories, pragmatic methods, and various scales of study contexts as promising solutions to address the complexity and heterogeneity of OTE. The study concludes that the conceptual structure of OTE is premised on a sustainability platform, which is influenced by socio-cultural, environmental, economic, and political issues. This study provides a road map that enlightens the current state of OTE, prevailing topics, and pathways for further research

Controlling surface statistical properties using bias voltage: Atomic force microscopy and stochastic analysis

The effect of bias voltages on the statistical properties of rough surfaces has been studied using atomic force microscopy technique and its stochastic analysis. We have characterized the complexity of the height fluctuation of a rough surface by the stochastic parameters such as roughness exponent, level crossing, and drift and diffusion coefficients as a function of the applied bias voltage. It is shown that these statistical as well as microstructural parameters can also explain the macroscopic property of a surface. Furthermore, the tip convolution effect on the stochastic parameters has been examined.Comment: 8 pages, 11 figures

Nonlinear Optical Response Functions of Mott Insulators Based on Dynamical Mean Field Approximation

We investigate the nonlinear optical susceptibilities of Mott insulators with the dynamical mean field approximation. The two-photon absorption (TPA) and the third-harmonic generation (THG) spectra are calculated, and the classification by the types of coupling to external fields shows different behavior from conventional semiconductors. The direct transition terms are predominant both in the TPA and THG spectra, and the importance of taking all types of interaction with the external field into account is illustrated in connection with the THG spectrum and dcKerr effect. The dependence of the TPA and THG spectra on the Coulomb interaction indicate a scaling relation. We apply this relation to the quantitative evaluation and obtain results comparable to those of experiments.Comment: 14 pages, 12 figure

Dynamical mean field theory of optical third harmonic generation

We formulate the third harmonic generation (THG) within the dynamical mean field theory (DMFT) approximation of the Hubbard model. In the limit of large dimensions, where DMFT becomes exact, the vertex corrections to current vertices are identically zero, and hence the calculation of the THG spectrum reduces to a time-ordered convolution, followd by appropriate analytic continuuation. We present the typical THG spectrum of the Hubbard model obtained by this method. Within our DMFT calculation, we observe a nontrivial approximate {\em scaling} function describing the THG spectra in all Mott insulators, independent of the gap magnitude.Comment: 4 eps figure