361 research outputs found

    Magneto-optical study of thermally annealed InAs-InGaAs-GaAs self-assembled quantum dots

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    We report a magneto-optical study of InAs-InGaAs-GaAs self-assembled quantum dots (QDs) subjected to post-growth thermal annealing at different temperatures. At low temperatures annealing strongly affects the bimodal distribution of QDs; at higher temperatures a strong blueshift of the emission occurs. Magnetophotoluminescence reveals that the annealing increases the QD size, with a larger effect occurring along the growth axis, and decreases the carrier effective masses. The main contribution to the blueshift is deduced to be an increase in the average Ga composition of the QDs. The inadvertent annealing which occurs during the growth of the upper AlGaAs cladding layer in laser structures is also studied

    Societal and cultural research opportunities at a deep UK geological carbon dioxide storage research facility : results from a social science ‘sandpit’ discussion

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    This report describes the outcomes of a sandpit activity in December 2021, and initial follow up discussions, designed to bring together academics from across and beyond the UK, as well as members of public sector organisations. The intended outcomes were to discuss and develop societal and cultural research opportunities as part of a scoping study for a UK CO2 storage research facility. These outcomes are a research community view that inform the questions and knowledge gaps that a research facility would address. The sandpit is the first of many activities that will enable us to build an evidence base to demonstrate how a research facility would benefit from societal and cultural research and unlock new research themes. In particular, how the identified research themes support the UK’s transition to a sustainable future. The following themes were identified: • the role of culture and heritage in shaping community views and energy literacy; • placed-based and participatory research and the links between people’s sense of place and new energy infrastructure activities; • the value of tacit knowledge and collective memory to support co-design and community agency; • energy justice in support of a just and inclusive energy transition; • good governance to support ethical and responsible innovation; • benefits and risks, inclusive knowledge production and community involvement in decision making; • social conflict, controversies and trust in ‘energy actors’; • existing CO2 storage narratives and how these might be changed; • use of creative arts-based approaches to deepen community engagement; • the CO2 storage research facility as a ‘public lab’ to support a range of engagement approaches. Recommendations are made in this report concerning the development a new programme of integrated, interdisciplinary and inclusive research, based on priority research themes, in a timely fashion to ensure maximum benefit and impact. We also recommend that a cross-research council funding strategy is developed in support of this research. We suggest that developing such an integrated programme would: enable community agency in the development and co-design of a CO2 storage research facility; encourage dialogue and investment in wider carbon mitigation strategies and support localised behaviour change; embed an understanding of the role CO2 storage could play in the energy transition; and enable positive, transparent and inclusive energy and climate policy development both locally and nationally

    Virtual patients design and its effect on clinical reasoning and student experience : a protocol for a randomised factorial multi-centre study

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    Background Virtual Patients (VPs) are web-based representations of realistic clinical cases. They are proposed as being an optimal method for teaching clinical reasoning skills. International standards exist which define precisely what constitutes a VP. There are multiple design possibilities for VPs, however there is little formal evidence to support individual design features. The purpose of this trial is to explore the effect of two different potentially important design features on clinical reasoning skills and the student experience. These are the branching case pathways (present or absent) and structured clinical reasoning feedback (present or absent). Methods/Design This is a multi-centre randomised 2x2 factorial design study evaluating two independent variables of VP design, branching (present or absent), and structured clinical reasoning feedback (present or absent).The study will be carried out in medical student volunteers in one year group from three university medical schools in the United Kingdom, Warwick, Keele and Birmingham. There are four core musculoskeletal topics. Each case can be designed in four different ways, equating to 16 VPs required for the research. Students will be randomised to four groups, completing the four VP topics in the same order, but with each group exposed to a different VP design sequentially. All students will be exposed to the four designs. Primary outcomes are performance for each case design in a standardized fifteen item clinical reasoning assessment, integrated into each VP, which is identical for each topic. Additionally a 15-item self-reported evaluation is completed for each VP, based on a widely used EViP tool. Student patterns of use of the VPs will be recorded. In one centre, formative clinical and examination performance will be recorded, along with a self reported pre and post-intervention reasoning score, the DTI. Our power calculations indicate a sample size of 112 is required for both primary outcomes

    p-doped 1.3 μm InAs/GaAs quantum-dot laser with a low threshold current density and high differential efficiency

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    Amodification of the thickness of the low-growth- emperature component of the GaAs spacer layers in multilayer 1.3 um InAs/GaAs quantum-dot (QD) lasers has been used to significantly improve device performance. For a p-doped seven-layer device, a reduction in the thickness of this component from 15 to 2 nm results in a reduced reverse bias leakage current and an increase in the intensity of the spontaneous emission. In addition, a significant reduction of the threshold current density and an increase of the external differential efficiency at room temperature are obtained. These improvements indicate a reduced defect density, most probably a combination of the selective elimination of a very low density of dislocated dots and a smaller number of defects in the thinner low-growth-temperature component of the GaAs spacer layer

    The structural properties of sexual fantasies for sexual offenders : a preliminary model

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    While the phenomenon of sexual fantasy has been researched extensively, little contemporary inquiry has investigated the structural properties of sexual fantasy within the context of sexual offending. In this study, a qualitative analysis was used to develop a descriptive model of the phenomena of sexual fantasy during the offence process. Twenty-four adult males convicted of sexual offences provided detailed retrospective descriptions of their thoughts, emotions and behaviours—before, during and after their offences. A data-driven approach to model development, known as Grounded Theory, was undertaken to analyse the interview transcripts. A model was developed to elucidate the structural properties of sexual fantasy in the process of sexual offending, as well as the physiological and psychological variables associated with it. The Sexual Fantasy Structural Properties Model (SFSPM) comprises eight categories that describe various properties of sexual fantasy across the offence process. These categories are: origin, context, trigger, perceptual modality, clarity, motion, intensity and emotion. The strengths of the SFSPM are discussed and its clinical implications are reviewed. Finally, the limitations of the study are presented and future research directions discussed

    A cognitive framework for object recognition with application to autonomous vehicles

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    Autonomous vehicles or self-driving cars are capable of sensing the surrounding environment so they can navigate roads without human input. Decisions are constantly made on sensing, mapping and driving policy using machine learning techniques. Deep Learning – massive neural networks that utilize the power of parallel processing – has become a popular choice for addressing the complexities of real time decision making. This method of machine learning has been shown to outperform alternative solutions in multiple domains, and has an architecture that can be adapted to new problems with relative ease. To harness the power of Deep Learning, it is necessary to have large amounts of training data that are representative of all possible situations the system will face. To successfully implement situational awareness in driverless vehicles, it is not possible to exhaust all possible training examples. An alternative method is to apply cognitive approaches to perception, for situations the autonomous vehicles will face. Cognitive approaches to perception work by mimicking the process of human intelligence – thereby permitting a machine to react to situations it has not previously experienced. This paper proposes a novel cognitive approach for object recognition. The proposed cognitive object recognition algorithm, referred to as Recognition by Components, is inspired by the psychological studies pertaining to early childhood development. The algorithm works by breaking down images into a series of primitive forms such as square, triangle, circle or rectangle and memory based aggregation to identify objects. Experimental results suggest that Recognition by Component algorithm performs significantly better than algorithms that require large amounts of training data

    Sex and sexuality: An evolutionary view

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    In this article, I first offer a summary of Darwin’s main ideas, especially relating to sex, and explain how these have been elaborated by more recent evolutionary scholars. I then give an account of the historical divergence between psychoanalysis and classical Darwinian thought, and describe how the early psychoanalyst Sabina Spielrein tried to counter this by addressing some biological themes in her work. Following a review of some contemporary attempts to bring psychoanalysis and evolutionary thought into alignment with each other, I make some suggestions regarding a view of sex and sexuality that would be sound in evolutionary terms while also being helpful in psychoanalytic ones
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