Visible and infrared photocurrent enhancement in a graphene-silicon Schottky photodetector through surface-states and electric field engineering

The design of efficient graphene-silicon (GSi) Schottky junction photodetectors requires detailed understanding of the spatial origin of the photoresponse. Scanning-photocurrent-microscopy (SPM) studies have been carried out in the visible wavelengths regions only, in which the response due to silicon is dominant. Here we present comparative SPM studies in the visible ($\lambda$ = 633nm) and infrared ($\lambda$ = 1550nm) wavelength regions for a number of GSi Schottky junction photodetector architectures, revealing the photoresponse mechanisms for silicon and graphene dominated responses, respectively, and demonstrating the influence of electrostatics on the device performance. Local electric field enhancement at the graphene edges leads to a more than ten-fold increased photoresponse compared to the bulk of the graphene-silicon junction. Intentional design and patterning of such graphene edges is demonstrated as an efficient strategy to increase the overall photoresponse of the devices. Complementary simulations and modeling illuminate observed effects and highlight the importance of considering graphene's shape and pattern and device geometry in the device design

Constraints and tensions in testing general relativity from Planck and CFHTLenS data including intrinsic alignment systematics

We present constraints on testing general relativity (GR) at cosmological scales using recent data sets and assess the impact of galaxy intrinsic alignment in the CFHTLenS lensing data on those constraints. We consider data from Planck temperature anisotropies, the galaxy power spectrum from the WiggleZ survey, weak-lensing tomography shear-shear cross-correlations from the CFHTLenS survey, integrated Sachs Wolfe-galaxy cross-correlations, and baryon acoustic oscillation data. We use three different parametrizations of modified gravity (MG), one that is binned in redshift and scale, a parametrization that evolves monotonically in scale but is binned in redshift, and a functional parametrization that evolves only in redshift. We present the results in terms of the MG parameters Q and Sigma. We employ an intrinsic alignment model with an amplitude A(CFHTLenS) that is included in the parameter analysis. We find an improvement in the constraints on the MG parameters corresponding to a 40-53% increase on the figure of merit compared to previous studies, and GR is found consistent with the data at the 95% confidence level. The bounds found on ACFHTLenS are sensitive to the MG parametrization used, and the correlations between ACFHTLenS and MG parameters are found to be weak to moderate. For all three MG parametrizations ACFHTLenS is found to be consistent with zero when the whole lensing sample is used; however, when using the optimized early-type galaxy sample a significantly nonzero A(CFHTLenS) is found for GR and the scale-independent MG parametrization. We find that the tensions observed in previous studies persist, and there is an indication that cosmic microwave background (CMB) data and lensing data prefer different values for MG parameters, particularly for the parameter Sigma. The analysis of the confidence contours and probability distributions suggest that the bimodality found follows that of the known tension in the sigma(8) parameter

Loop algorithm for Heisenberg models with biquadratic interaction and phase transitions in two dimensions

We present a new algorithm for quantum Monte Carlo simulation based on global updating with loops. While various theoretical predictions are confirmed in one dimension, we find, for S=1 systems on a square lattice with an antiferromagnetic biquadratic interaction, that the intermediate phase between the antiferromagnetic and the ferromagnetic phases is disordered and that the two phase transitions are both of the first order in contrast to the one-dimensional case. It is strongly suggested that the transition points coincide those at which the algorithm changes qualitatively.Comment: 4 pages including 4 figures, to appear in JPS

Study on Doping Prevention: A map of Legal, Regulatory and Prevention Practice Provisions in EU 28

Historically, anti-doping efforts have focused on the detection and deterrence of doping in elite and competitive sport. There is, however, a growing concern that doping is occurring outside the organised sporting system; giving rise to the belief that the misuse of doping agents in recreational sport has become a societal problem and a public health issue that must be addressed. The EU Commission awarded a contract (EAC/2013/0617) to a Consortium to undertake this Study with the aim of developing the evidence-base for policies designed to combat doping in recreational sport. Fourteen internationally recognised experts shaped the Study which comprised (i) the collection of primary data through a structured survey, and (ii) secondary data through literature searches and website analysis. All 28 Member States participated in the information-gathering process. Specifically, this involved a systematic study of the ethical considerations, legal position, prevention research landscape, and current practise in relation to the prevention of doping in recreational sport. The Study provides a comprehensive overview of current practice and legislation as it applies to the prevention of doping and promotes and supports the sharing of best practices in the EU regarding the fight against doping in recreational sport. It concludes with seven recommendations for future action that focus on the need for a coordinated response in relation to the problems arising from doping in recreational sport

'It's always difficult when it's family. . . whereas when you're talking to a therapist. . .': Parents' views of cognitive-behaviour therapy for depressed adolescents

BACKGROUND: Parents are key to helping their adolescent child access psychological therapy for mental health problems such as depression. However, little is known about how parents experience their child's psychological therapy. We aimed to explore parents' experiences of their adolescent child's cognitive behaviour therapy for depression. METHOD: We applied Thematic Analysis (TA) to qualitative data from in-depth interviews with parents (N = 16) whose adolescent child was randomly allocated to CBT in a large multisite RCT for adolescent depression (the IMPACT trial). Interviews were conducted at the end of treatment. RESULTS: We generated two main themes: parents' perceptions of the adolescent's journey through therapy, and parents' perceptions of the therapeutic setting and process. Each included four sub-themes. Parents talked about key factors that impacted on their child's progress through treatment, including the adolescent's readiness for therapy and the adolescent-therapist relationship. CONCLUSION: Parents' insights confirm the foundations of what is considered good clinical practice of CBT for adolescent depression, including tailoring therapy to the adolescent, and establishing a strong adolescent-therapist relationship. Parents recognised that, for CBT to be helpful, their child had to be willing to engage in therapy and able to develop a trusting relationship with their therapist

Exact solution of A-D Temperley-Lieb Models

We solve for the spectrum of quantum spin chains based on representations of the Temperley-Lieb algebra associated with the quantum groups {\cal U}_q(X_n } for X_n = A_1,B_n,C_n$and$D_n$. We employ a generalization of the coordinate Bethe-Ansatz developed previously for the deformed biquadratic spin one chain. As expected, all these models have equivalent spectra, i.e. they differ only in the degeneracy of their eigenvalues. This is true for finite length and open boundary conditions. For periodic boundary conditions the spectra of the lower dimensional representations are containded entirely in the higher dimensional ones. The Bethe states are highest weight states of the quantum group, except for some states with energy zero

A multi-criteria model analysis framework for assessing integrated water-energy system transformation pathways

Sustainable development objectives surrounding water and energy are interdependent, and yet the associated performance metrics are often distinct. Regional planners tasked with designing future supply systems therefore require multi-criteria analysis methods and tools to determine a suitable combination of technologies and scale of investments. Previous research focused on optimizing system development strategy with respect to a single design objective, leading to potentially negative outcomes for other important sustainability metrics. This paper addresses this limitation, and presents a flexible multi-criteria model analysis framework that is applicable to long-term energy and water supply planning at national or regional scales in an interactive setup with decision-makers. The framework incorporates a linear systems-engineering model of the coupled supply technologies and inter-provincial transmission networks. The multi-criteria analysis approach enables the specification of diverse decision-making preferences for disparate criteria, and leads to quantitative understanding of trade-offs between the resulting criteria values of the corresponding Pareto-optimal solutions. A case study of the water-stressed nation of Saudi Arabia explores preferences combining aspiration and reservation levels in terms of cost, water sustainability and electricity sector CO2 emissions. The analysis reveals a suite of trade-off solutions, in which potential integrated water-energy system configurations remain relatively ambitious from both an economic and environmental perspective. The results highlight the importance of identifying suitable tradeoffs between water and energy sustainability objectives during the formulation of coupled transformation strategies

Framework analysis: a worked example of a study exploring young people’s experiences of depression

Framework analysis is an approach to qualitative research which is being increasingly used across multiple disciplines, including psychology, social policy and nursing research. The stages of framework analysis have been described in published work, but the literature is lacking in articles describing how to conduct it in practice, particularly in the field of psychology, where researchers may be working as part of a team. Having used framework analysis on a study exploring adolescents' experiences of depression, we faced various challenges along the way and learned from experience how to use this approach to qualitative analysis. In this reflective article, we describe a worked example of using framework, which we hope will assist other researchers in deciding if this approach is suitable for their own research, and will provide guidance on how one might go about conducting framework analysis when working as part of a research team. We conclude that framework is a valuable contribution to qualitative methods in psychology, offering a pragmatic, flexible and rigorous approach to data analysis