382 research outputs found

    Electrochemistry in supercritical fluids

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    A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ratio nanopores and the use of metallocenes as redox probes and standards in both supercritical carbon dioxide–acetonitrile and supercritical HFCs

    The effect of boundary adaptivity on hexagonal ordering and bistability in circularly confined quasi hard discs

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    The behaviour of materials under spatial confinement is sensitively dependent on the nature of the confining boundaries. In two dimensions, confinement within a hard circular boundary inhibits the hexagonal ordering observed in bulk systems at high density. Using colloidal experiments and Monte Carlo simulations, we investigate two model systems of quasi hard discs under circularly symmetric confinement. The first system employs an adaptive circular boundary, defined experimentally using holographic optical tweezers. We show that deformation of this boundary allows, and indeed is required for, hexagonal ordering in the confined system. The second system employs a circularly symmetric optical potential to confine particles without a physical boundary. We show that, in the absence of a curved wall, near perfect hexagonal ordering is possible. We propose that the degree to which hexagonal ordering is suppressed by a curved boundary is determined by the `strictness' of that wall.Comment: 10 pages, 8 figure

    The Forensic Restrictiveness Questionnaire : development, validation and revision

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    Introduction: Forensic psychiatric care is often practiced in closed institutions. These highly regulated, secure, and prescriptive environments arguably reduce patient autonomy, self-expression, and personhood. Taken together these settings are restrictive as patients’ active participation in clinical, organizational, community, and personal life-worlds are curtailed. The consequences of patients’ experiences of restrictiveness have not been explored empirically. This study aimed to develop a psychometrically-valid measure of experiences of restrictiveness. This paper presents the development, validation, and revision of the Forensic Restrictiveness Questionnaire (FRQ). Methods: In total, 235 patients recruited from low, medium, and high secure hospitals across England completed the FRQ. The dimensionality of the 56-item FRQ was tested using Principle Axis Factor Analysis and parallel analysis. Internal consistency was explored with Cronbach’s α. Ward climate (EssenCES) and quality of life (FQL-SV) questionnaires were completed by participants as indicators of convergent validity. Exploratory Factor Analysis (EFA) and Cronbach’s α guided the removal of items that did not scale adequately. Results: The analysis indicated good psychometric properties. EFA revealed a unidimensional structure, suggesting a single latent factor. Convergent validity was confirmed as the FRQ was significantly negatively correlated with quality of life (Spearman’s ρ = −0.72) and ward climate (Spearman’s ρ = −0.61). Internal consistency was strong (α = 0.93). Forty-one items were removed from the pilot FRQ. The data indicate that a final 15-item FRQ is a valid and internally reliable measure. Conclusion: The FRQ offers a novel and helpful method for clinicians and researchers to measure and explore forensic patients’ experiences of restrictiveness within secure hospitals

    Treadmill Platform for Quadrupedal Robots

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    Cal Poly Legged Robots, led by Professor Refvem and Professor Xing, has been leading Cal Poly’s attempts to simulate, produce, and test their legged robots. The initial testing of the locomotion of these robots can be dangerous to the robot since any bugs in the code could cause the robot to fall over and harm itself. Our responsibility as a team was to deliver a portable platform for testing the locomotion capabilities containing a fall prevention mechanism. In short, we have designed a platform for this purpose that consists of a treadmill surrounded by a wheeled chassis with a system of ropes, pulleys, and a winch for a fall prevention mechanism. Our method of lifting the robot is a success in two ways. First, our method only requires the addition of four eyebolts to the robot, a rather minor modification. Second, our method does not impede the motion of the robot when it is running normally. However, it was found that our method requires 1-1.7 seconds to lift the robot (depending on where the robot is located on the treadmill) – a rather crippling amount of time to lift a robot, seeing as how it is desired for the robot to run at 8 mph on the treadmill. Regardless, our design provides a great starting point for future Senior Project teams to improve upon it. It is our hope that our design will allow Cal Poly Legged Robots to further the development of legged robots and to generate interest, both at Cal Poly and hopefully around the world, in this area of study

    Experiences of restrictiveness in forensic psychiatric care: systematic review and concept analysis

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    Mentally disordered offenders may be sent to secure psychiatric hospitals. These settings can resemble carceral spaces, employing high levels of security restricting resident autonomy, expression and social interaction. However, research exploring the restrictiveness of forensic settings is sparse. A systematic review was therefore undertaken to conceptualize this restrictiveness. Eight databases were searched for papers that address restrictive elements of secure forensic care in a non-cursory way. Fifty sources (empirical articles and policy documents) were included and subject to thematic analysis to identify 1) antecedent conditions to, 2) characteristic attributes, 3) consequences and 4) ‘deviant’ cases of the developing concept. The restrictiveness of forensic care was experienced across three levels: individual, institutional and systemic. Restrictiveness was subjective and included such disparate elements as limited leave and grounds access, ownership of personal belongings and staff attitudes. The manner and extent to which these are experienced as restrictive was influenced by two antecedent conditions; whether the purpose of forensic care was to be more caring or custodial and the extent to which residents were perceived to be risky. We argue that there must be a reflexivity from stakeholders between the level of restrictiveness needed to safely provide care in a therapeutic milieu and enable the maximum amount of resident autonomy

    Magnetic frustration and spontaneous rotational symmetry breaking in PdCrO2

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    In the triangular layered magnet PdCrO2 the intralayer magnetic interactions are strong, however the lattice structure frustrates interlayer interactions. In spite of this, long-range, 120∘^\circ antiferromagnetic order condenses at TN=38T_N = 38~K. We show here through neutron scattering measurements under in-plane uniaxial stress and in-plane magnetic field that this occurs through a spontaneous lifting of the three-fold rotational symmetry of the nonmagnetic lattice, which relieves the interlayer frustration. We also show through resistivity measurements that uniaxial stress can suppress thermal magnetic disorder within the antiferromagnetic phase.Comment: 9 pages, 9 figure

    From the tobacco industry's uses of science for public relations purposes to the alcohol industry: Tobacco industry documents study

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    Introduction Associates for Research in Substances of Enjoyment (ARISE) was formed by tobacco companies in the late 1980s designed to counter public health policy development. This study examines the alcohol content of ARISE and the contribution of ARISE to alcohol industry activities in a key period in the globalisation of the alcohol industry, generating insights into the inter-relationships between the tobacco and alcohol industries in their involvements in policy-oriented science. Methods We systematically searched the UCSF Truth Tobacco Documents Library for information about ARISE, alcohol and the alcohol industry. This material was supplemented with an analysis of the contributions by ARISE associates to one volume in the International Center for Alcohol Policies (ICAP) book series on alcohol and pleasure. Results ARISE placed nicotine alongside caffeine, chocolate and other foods, and alcohol as treats which brought pleasure and other benefits. Alcohol was thus intrinsic to the ARISE project for the tobacco industry. This study shows that at a formative moment in the mid-1990s the major alcohol companies took advantage of the intellectual inheritance and personnel provided by the tobacco industry when establishing ICAP. Key to this was an ICAP conference that resulted in Alcohol and pleasure: A health perspective (1999). Discussion and Conclusions Not only did ARISE use alcohol to play a supporting role in a sophisticated tobacco industry strategy, the alcohol industry engaged with ARISE as part of its own strategy. This shows the importance of careful attention to corporate activities on the fringes of peer-reviewed science

    The social and cultural context of remembering : implications for recalling childhood sexual abuse

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    Remembering is a social cultural activity. Contributors to this Special Issue were asked to address how conversations about personally experienced past events might or might not influence subsequent memory, especially in light of current controversies regarding historical memories of sexual abuse. For many years, the study of human memory focused on the individual engaging in a cognitive activity that produced a specific representation of a past event at a specific time point. But as the papers in this issue make clear, memory is an active ongoing social process that has cascading effects over time, an idea first developed by Bartlett (1932) and championed by Neisser (1982). Even when reminiscing to ourselves, there is an imagined audience, a way of expressing memories of our past selves to our current selves (Halbwachs, 1925/1952). What is remembered about any given event on any given day will depend on both the history of that memory, the specific local context within which the individual is remembering, and the larger sociocultural developmental history within which the individual is embedded (Nelson & Fivush, 2004). In this commentary, we pull the threads through these contributions, and discuss three major factors that contribute to remembering: language, emotion and time. These are, obviously, “big” constructs, but we try to weave together arguments and findings presented across the contributions to this issue. We end with some thoughts on what this might mean specifically for remembering childhood sexual abuse