Self-aligned 0.12mm T-gate In.53Ga.47As/In.52Al.48As HEMT Technology Utilising a Non Annealed Ohmic Contact Strategy

An InGaAs/InAlAs based HEMT structure, lattice matched to an InP substrate, is presented in which drive current and transconductance has been optimized through a double-delta doping strategy. Together with an increase in channel carrier density, this allows the use of a non-annealed ohmic contact process. HEMT devices with 120 nm standard and self-aligned T-gates were fabricated using the non-annealed ohmic process. At DC, self-aligned and standard devices exhibited transconductances of up to 1480 and 1100 mS/mm respectively, while both demonstrated current densities in the range 800 mA/mm. At RF, a cutoff frequency f/sub T/ of 190 GHz was extracted for the self-aligned device. The DC characteristics of the standard devices were then calibrated and modelled using a compound semiconductor Monte Carlo device simulator. MC simulations provide insight into transport within the channel and illustrate benefits over a single delta doped structure

Introduction: building the history of language learning and teaching (HoLLT)

The papers presented in this issue are the result of a workshop held at the University of Nottingham in December 2012 as part of an Arts and Humanities Research Council research network Towards a History of Modern Foreign Language Teaching and Learning (2012–14) intended to stimulate historical research into language teaching and learning. This, the first workshop in the programme, focused on exchanging information on the history of language learning and teaching (HoLLT) across the different language traditions, for it had become clear to us that scholars working within their own language disciplines were often relatively unaware of work outside these. We hope that this special issue — with overview articles on the history of English, French, German, and Spanish as second/foreign languages — will help overcome that lack of awareness and facilitate further research collaboration. Charting the history of language teaching and learning will, in turn, make us all better informed in facing challenges and changes to policy and practice now and in the future. It is instructive in the current climate, for example, to realize that grave doubts were held about whether second foreign languages could survive alongside French in British schools in the early twentieth century (McLelland, forthcoming), or to look back at earlier attempts to establish foreign languages in primary schools (Bayley, 1989; Burstall et al., 1974; Hoy, 1977). As we write, language learning in England is undergoing yet more radical change. Language teaching for all children from the age of seven is being made compulsory in primary schools from 2014, while at Key Stage 3 (up to age 16), where a foreign language has not been compulsory since 2002, the most recent programme of study for England has virtually abandoned the recent focus on intercultural competence and now requires learners to ‘read great literature in the original language’,1 a radical change in emphasis compared to the previous half-century, which seems to reflect a very different view of what language learning is for. We seem to be little closer in 2014 than we were at the dawn of the twentieth century to answering with any certainty the questions that lie at the very foundations of language teaching: who should learn a foreign language, why learners learn, what they need to learn, and what we want to teach them — answers that we need before we can consider how we want to teach. The research programme begun under our research network is intended to help us to take ‘the long view’ on such questions

Completeness of intervention reporting in randomised trials of technology-enabled remote or hybrid exercise-based cardiac rehabilitation: a systematic review using the TIDieR framework

Background: Exercise-based cardiac rehabilitation improves clinical outcomes and quality of life. Technology-enabled delivery of remote cardiac rehabilitation is as effective in improving health outcomes as in-person delivery and has the potential to transform clinical service delivery. However, for the successful translation of research to clinical practice, interventions must be adequately reported in the literature. Methods: Systematic review of MedLine, CINAHL, PubMed and SPORT Discus databases applying PRISMA guidance. Randomised controlled trials of remote or hybrid technology-enabled exercise-based cardiac rehabilitation interventions were included. Completeness of reporting was evaluated against the TIDieR checklist. Results: The search strategy returned 162 articles which, following screening, resulted in 12 randomised trials being included containing data for 1588 participants. No trial fully reported their rehabilitation intervention as per the 12-item TIDieR checklist, with a median score of eight out of 12 categories. Notably, intervention detail, dosage and modification were comparatively poorly reported. Conclusion: Technology-enabled remotely delivered cardiac rehabilitation may be effective at improving cardiovascular fitness; however, the quality of reporting of these interventions in randomised trials is insufficient for replication which has material implications for translation into clinical practice.</p

Le magmatisme de la région de Kwyjibo, Province\ud du Grenville (Canada) : intérêt pour les\ud minéralisations de type fer-oxydes associées

The granitic plutons located north of the Kwyjibo property in Quebec’s Grenville Province are of\ud Mesoproterozoic age and belong to the granitic Canatiche Complex . The rocks in these plutons are calc-alkalic, K-rich,\ud and meta- to peraluminous. They belong to the magnetite series and their trace element characteristics link them to\ud intraplate granites. They were emplaced in an anorogenic, subvolcanic environment, but they subsequently underwent\ud significant ductile deformation. The magnetite, copper, and fluorite showings on the Kwyjibo property are polyphased\ud and premetamorphic; their formation began with the emplacement of hydraulic, magnetite-bearing breccias, followed by\ud impregnations and veins of chalcopyrite, pyrite, and fluorite, and ended with a late phase of mineralization, during\ud which uraninite, rare earths, and hematite were emplaced along brittle structures. The plutons belong to two families:\ud biotite-amphibole granites and leucogranites. The biotite-amphibole granites are rich in iron and represent a potential\ud heat and metal source for the first, iron oxide phase of mineralization. The leucogranites show a primary enrichment in\ud REE (rare-earth elements), F, and U, carried mainly in Y-, U-, and REE-bearing niobotitanates. They are metamict and\ud underwent a postmagmatic alteration that remobilized the uranium and the rare earths. The leucogranites could also be\ud a source of rare earths and uranium for the latest mineralizing events

Synaptic dysfunction, memory deficits and hippocampal atrophy due to ablation of mitochondrial fission in adult forebrain neurons

Well-balanced mitochondrial fission and fusion processes are essential for nervous system development. Loss of function of the main mitochondrial fission mediator, dynamin-related protein 1 (Drp1), is lethal early during embryonic development or around birth, but the role of mitochondrial fission in adult neurons remains unclear. Here we show that inducible Drp1 ablation in neurons of the adult mouse forebrain results in progressive, neuronal subtype-specific alterations of mitochondrial morphology in the hippocampus that are marginally responsive to antioxidant treatment. Furthermore, DRP1 loss affects synaptic transmission and memory function. Although these changes culminate in hippocampal atrophy, they are not sufficient to cause neuronal cell death within 10 weeks of genetic Drp1 ablation. Collectively, our in vivo observations clarify the role of mitochondrial fission in neurons, demonstrating that Drp1 ablation in adult forebrain neurons compromises critical neuronal functions without causing overt neurodegeneration

The pharmacological regulation of cellular mitophagy

Small molecules are pharmacological tools of considerable value for dissecting complex biological processes and identifying potential therapeutic interventions. Recently, the cellular quality-control process of mitophagy has attracted considerable research interest; however, the limited availability of suitable chemical probes has restricted our understanding of the molecular mechanisms involved. Current approaches to initiate mitophagy include acute dissipation of the mitochondrial membrane potential (ΔΨm) by mitochondrial uncouplers (for example, FCCP/CCCP) and the use of antimycin A and oligomycin to impair respiration. Both approaches impair mitochondrial homeostasis and therefore limit the scope for dissection of subtle, bioenergy-related regulatory phenomena. Recently, novel mitophagy activators acting independently of the respiration collapse have been reported, offering new opportunities to understand the process and potential for therapeutic exploitation. We have summarized the current status of mitophagy modulators and analyzed the available chemical tools, commenting on their advantages, limitations and current applications

Asymmetric effects of a modelled tidal turbine on the flow and seabed

The extraction of power from the flow of water has become an important potential source of clean energy. In spite of significant interest in the interaction between energy extraction devices and water currents, comparatively little work has focused on flow asymmetry. Indeed, unusual wake behaviour and limits of turbine array efficiency have typically been attributed to boundary effects rather than the particular turbine geometry. The aim of the present study was to reveal the asymmetries in the hydrodynamic wake and the interactions with the sediment bed due to the presence of a hydrokinetic turbine. We combined: (i) computational fluid dynamics simulations; (ii) optical flow measurements from a series of flume experiments above a fixed rough bed; and (iii) acoustic measurements from a further series of flume experiments above a mobile sand bed. Results showed flow asymmetry due to the presence of the rotor which appeared to be related to the development of the wake and potentially to the gyre of the blades. Suspended sediments in the flume also exhibited asymmetrical characteristics due to the flow asymmetry. This imbalance in the flow field and sediment transport may decrease energy extraction efficiency in turbine arrays and also could have important environmental consequences

Laboratory study on the effects of hydro kinetic turbines on hydrodynamics and sediment dynamics

© 2018 The Authors The need for hydrokinetic turbine wake characterisation and their environmental impact has led to a number of studies. However, a small number of them have taken into account mobile sediment bed effects. The aim of the present work is to study the impact of the presence of a horizontal-axis three-bladed turbine with the flow and a mobile sediment bed. We use a series of laboratory experiments with a scaled modelled turbine installed in a flume with a mobile sandy bed at the bottom. Acoustic instruments were used to monitor flow, suspended sediment and bed behaviour. Results show a velocity decrease of about 50% throughout the water column and no flow recovery after a distance of 15 rotor diameters. Clearly visible ripples in the absence of the model turbine were replaced by horseshoe-shaped scour pit in the near wake region, and a depositional heap in the far wake. Suspended sediment differences were recorded in the streamwise direction with a possible effect of the wake as far as 15 rotor diameters. These results imply potentially important effects on the efficiency of turbine arrays, if the flow were to be lower than expected, on turbine foundations and modify coastal sediment transport