Effect of Anisotropy on the Localization in a Bifractal System

Bifractal is a highly anisotropic structure where planar fractals are stacked to form a 3-dimensional lattice. The localization lengths along fractal structure for the Anderson model defined on a bifractal are calculated. The critical disorder and the critical exponent of the localization lengths are obtained from the finite size scaling behavior. The numerical results are in a good agreement with previous results which have been obtained from the localization lengths along the perpendicular direction. This suggests that the anisotropy of the embedding lattice structure is irrelevant to the critical properties of the localization.Comment: 3 pages, source TeX file and 3 epsi figures. submitted to PR

Cosmological Evolution of a Tachyon-Quintom Model of Dark Energy

In this work we study the cosmological evolution of a dark energy model with two scalar fields, i.e. the tachyon and the phantom tachyon. This model enables the equation of state $w$ to change from $w>-1$ to $w<-1$ in the evolution of the universe. The phase-space analysis for such a system with inverse square potentials shows that there exists a unique stable critical point, which has power-law solutions. In this paper, we also study another form of tachyon-quintom model with two fields, which voluntarily involves the interactions between both fields.Comment: 17 pages, 10 figure

Temporal networks of face-to-face human interactions

The ever increasing adoption of mobile technologies and ubiquitous services allows to sense human behavior at unprecedented levels of details and scale. Wearable sensors are opening up a new window on human mobility and proximity at the finest resolution of face-to-face proximity. As a consequence, empirical data describing social and behavioral networks are acquiring a longitudinal dimension that brings forth new challenges for analysis and modeling. Here we review recent work on the representation and analysis of temporal networks of face-to-face human proximity, based on large-scale datasets collected in the context of the SocioPatterns collaboration. We show that the raw behavioral data can be studied at various levels of coarse-graining, which turn out to be complementary to one another, with each level exposing different features of the underlying system. We briefly review a generative model of temporal contact networks that reproduces some statistical observables. Then, we shift our focus from surface statistical features to dynamical processes on empirical temporal networks. We discuss how simple dynamical processes can be used as probes to expose important features of the interaction patterns, such as burstiness and causal constraints. We show that simulating dynamical processes on empirical temporal networks can unveil differences between datasets that would otherwise look statistically similar. Moreover, we argue that, due to the temporal heterogeneity of human dynamics, in order to investigate the temporal properties of spreading processes it may be necessary to abandon the notion of wall-clock time in favour of an intrinsic notion of time for each individual node, defined in terms of its activity level. We conclude highlighting several open research questions raised by the nature of the data at hand.Comment: Chapter of the book "Temporal Networks", Springer, 2013. Series: Understanding Complex Systems. Holme, Petter; Saram\"aki, Jari (Eds.

Alteration in the plasma concentration of a DAAO inhibitor, 3-methylpyrazole-5-carboxylic acid, in the ketamine-treated rats and the influence on the pharmacokinetics of plasma d-tryptophan

A determination method for 3-methylpyrazole-5-carboxylic acid (MPC), an inhibitor of d-amino acid oxidase (DAAO), in rat plasma was developed by using high-performance liquid chromatography-mass spectrometry (LC-MS). The structural isomer of MPC, 3-methylpyrazole-4-carboxylic acid, was used as an internal standard, and the intra- and inter-day accuracies and precisions were satisfactory for the determination of plasma MPC

Drug use among British Bangladeshis in London: a macro-structural perspective focusing on disadvantages contributing to individuals’ drug use trajectories and engagement with treatment services

Aims: The main aim of our study was to produce an understanding of factors contributing to drug-using trajectories among men and women from a Bangladeshi background living in East London. Methods: Fifteen semi-structured, one-to-one interviews were conducted with male and female Bangladeshi drug users accessing treatment services. A macro-structural lens was adopted to interpret participants’ accounts of their drug use and explored the intersecting factors that at a micro, meso, and macro level impacted on their drug-using trajectories. Findings: Problem drug use (heroin and crack cocaine) among participants was the result of inter-related factors such as their friendship networks and the embeddedness of drugs in drug-using networks, the structural disadvantages participants experienced, and the need for concealment of their drug use which impacted on participants’ effective utilisation of drug treatment services. Problem drug use was a functional way of responding to and dealing with social, economic, and cultural disconnection from mainstream institutions as participants faced severe multiple disadvantages engendering stigma and shame. Conclusions: We propose a ‘life-focused’ intervention aimed at creating extra opportunities and making critically-needed resources available in the marginalised environment of the study’s participants, which are key to restoring and maintaining agency and sustaining well-being

Urban assets and the financialisation fix: land tenure, renewal and path dependency in the city of Birmingham

Cities are places of incremental decision-making involving complex negotiations that produce accumulations of urban assets and path dependency. The ownership, control and co-ordination of urban land and its transformation into an investment asset is a key link between economic interests and urban activities that come together in site-based “financialisation fixes”. A financialisation fix combines a development solution for a specific site with a financial model creating a locally embedded asset. This article examines how land tenure (freehold versus leasehold rights) influences the transformation of a city and the role a local authority plays in the financial management of land assets. This includes an analysis of the application of financialisation to urban assets and the first tax increment financing scheme of 1875