Consuming identity : the case of Scotland

The paper examines national identity in Scotland. The research explores how consumers perceive the symbols used to represent Scotland, how these symbols relate to their perceptions of contemporary Scottish identity and their responses to the use of these symbols to promote Scotland and Scottishness. A series of in-depth interviews revealed that national identity in Scotland was seen to be multidimensional. Activities associated with art and culture, as opposed to business and industry, were identified as primary characteristics of contemporary Scotland. The traditional symbols of Scottish identity (e.g. tartan and whiskey) remain dominant signifiers, however, and the problems of this are discussed

Dominant role of many-body effects on the carrier distribution function of quantum dot lasers

The effects of free-carrier-induced shift and broadening on the carrier distribution function are studied considering different extreme cases for carrier statistics (Fermi–Dirac and random carrier distributions) as well as quantum dot (QD) ensemble inhomogeneity and state separation using a Monte Carlo model. Using this model, we show that the dominant factor determining the carrier distribution function is the free carrier effects and not the choice of carrier statistics. By using empirical values of the free-carrier-induced shift and broadening, good agreement is obtained with experimental data of QD materials obtained under electrical injection for both extreme cases of carrier statistics

Epitaxial designs for maximizing efficiency in resonant tunnelling diode based terahertz emitters

We discuss the modelling of high current density InGaAs/AlAs/InP resonant tunneling diodes to maximize their efficiency as THz emitters. A figure of merit which contributes to the wall plug efficiency, the intrinsic resonator efficiency, is used for the development of epitaxial designs. With the contribution of key parameters identified, we analyze the limitations of accumulated stress to assess the manufacturability of such designs. Optimal epitaxial designs are revealed, utilizing thin barriers, with a wide and shallow quantum well that satisfies the strained layer epitaxy constraint. We then assess the advantages to epitaxial perfection and electrical characteristics provided by devices with a narrow InAs sub-well inside a lattice-matched InGaAs alloy. These new structures will assist in the realization of the next-generation submillimeter emitters

Isolation and characterization of microsatellites in the lichen Buellia frigida (Physciaceae), an Antarctic endemic

Premise of the study: Microsatellite markers were characterized for an Antarctic endemic, Buellia frigida, to investigate population structure and origin of Antarctic lichens. Methods and Results: Five primer sets were characterized. All loci were polymorphic with eight to 16 alleles per locus in a sample of 59 lichens. Conclusions: The microsatellite markers potentially provide insight into population structure and gene flow of B. frigida

The Swift BAT Survey Detects Two Optical Broad Line, X-ray Heavily Obscured Active Galaxies: NVSS 193013+341047 and IRAS 05218-1212

The Swift Burst Alert Telescope (BAT) is discovering interesting new objects while monitoring the sky in the 14-195 keV band. Here we present the X-ray properties and spectral energy distributions for two unusual AGN sources. Both NVSS 193013+341047 and IRAS 05218-1212 are absorbed, Compton-thin, but heavily obscured (NH \sim 10^23 cm-2), X-ray sources at redshifts < 0.1. The spectral energy distributions reveal these galaxies to be very red, with high extinction in the optical and UV. A similar SED is seen for the extremely red objects (EROs) detected in the higher redshift universe. This suggests that these unusual BAT-detected sources are a low- redshift (z << 1) analog to EROs, which recent evidence suggests are a class of the elusive type II quasars. Studying the multi-wavelength properties of these sources may reveal the properties of their high redshift counterparts.Comment: 20 pages, accepted to Ap

Evaluating resonances in PCSEL structures based on modal indices

The frequently sought after combination of characteristics in semiconductor lasers of high power together with narrow beam divergence and monochromatic output is usually difficult to attain. The photonic crystal surface emitting laser (PCSEL) is one category of device, however, which tends to provide the above-mentioned desirable output features. The PCSEL uses a large area optically active surface but with a two-dimensional periodic structure that enables it to generate high power in a narrow vertically emitted beam yet maintaining single wavelength operation. A primary requirement to model PCSELs is to obtain the optical field resonances that identify the lasing mode. This study presents an alternative method for evaluating the resonances, based essentially on the transfer-matrix technique and wave propagation in multilayer medium, which is relatively easy to formulate, and has quite modest demands on computing requirements

Characterisation of High Current Density Resonant Tunneling Diodes for THz Emission Using Photoluminescence Spectroscopy

We discuss the numerical simulation of high current density InGaAs/AlAs/InP resonant tunneling diodes with a view to their optimization for application as THz emitters. We introduce a figure of merit based upon the ratio of maximum extractable THz power and the electrical power developed in the chip. The aim being to develop high efficiency emitters as output power is presently limited by catastrophic failure. A description of the interplay of key parameters follows, with constraints on strained layer epitaxy introduced. We propose an optimized structure utilizing thin barriers paired with a comparatively wide quantum well that satisfies strained layer epitaxy constraints

Growth of quantum three-dimensional structure of InGaAs emitting at ~1 µm applicable for a broadband near-infrared light source

We obtained a high-intensity and broadband emission centered at ~1 µm from InGaAs quantum three-dimensional (3D) structures grown on a GaAs substrate using molecular beam epitaxy. An InGaAs thin layer grown on GaAs with a thickness close to the critical layer thickness is normally affected by strain as a result of the lattice mismatch and introduced misfit dislocations. However, under certain growth conditions for the In concentration and growth temperature, the growth mode of the InGaAs layer can be transformed from two-dimensional to 3D growth. We found the optimal conditions to obtain a broadband emission from 3D structures with a high intensity and controlled center wavelength at ~1 µm. This method offers an alternative approach for fabricating a broadband near-infrared light source for telecommunication and medical imaging systems such as for optical coherence tomography