524 research outputs found

    Design principles of a rotating medium speed mechanism

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    Design principles of a medium speed mechanism (MSM) are presented, including discussion on the relative merits of beryllium and aluminium as structural materials. Rotating at a speed of 60 rpm, the application envisaged for the MSM was as a despin bearing for the despun platform or despun antenna of a spin stabilized satellite. The MSM was built and tested to qualification level and is currently undergoing real time life testing

    Development of a high stability pointing mechanism for wide application

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    A recurrent requirement of spaceborne instruments and communications equipment is that of accurate pointing. This need is recognizable in such diverse applications as Star Sensor trimming, Momentum Wheel gimballing, in-orbit adjustment or alignment of equipment, inter-satellite communication and Antenna Pointing. A pointing mechanism of novel design having several advantages over the more conventional gimbal, centre-pivoted, or cross axis pointing concepts is described

    A modular docking mechanism for in-orbit assembly and spacecraft servicing

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    A Docking Mechanism concept is described which is suitable for use with autonomous docking systems. The central feature of using simple cylindrical handles on one side and a type of prism seating on the other is offered as a practical method of achieving a standardized structural interface without freezing continued development of the latches, either technically or commercially. The main emphasis in docking mechanism concepts is in two directions: (1) a very simple docking mechanism, involving mainly the latch mechanism to achieve a structural link; and (2) a sophisticated Docking Mechanism, where the latch mechanism is designed for nonrigid spacecraft and the achievement of very low dynamic interactions between spacecraft during the docking process

    Current European developments in solar paddle drives

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    The European Space Research and Technology Centre (ESTEC) is sponsoring the development of a number of critical spacecraft hardware items. The hardware under development includes two competing solar paddle drives which are being produced to similar specifications. Three mechanisms of each type are being produced and will undergo thermal vacuum testing. All mechanisms have lead lubricated bearings

    Availability and Use of Water in Nebraska, 1975

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    Student Volunteering and Global Citizenship at UCL

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    This paper is based on a small study of UCL student volunteers doing placements through the Volunteering Services Unit (VSU) in 2016. The research aimed to identify the extent to which UCL students who engage in volunteering activities through UCL see a connection between their experience and UCL’s mission of equipping graduates to be ‘global citizens’. We were interested in how students understand the concept of global citizenship, how aware there were of this agenda at UCL, and to what extent their understandings aligned with UCL goals. We were also keen to explore whether students made links between volunteering and global citizenship, as well as how their volunteering and ideas about global citizenship related to their degree

    Cognitive behavioural therapy for psychosis: The end of the line or time for a new approach?

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    Purpose Following its introduction in the early 1990s, cognitive behavioural therapy for psychosis (CBTp) has been evaluated in a large number of clinical trials and is now established as a recommended treatment in the UK National Health Service and elsewhere in the world. Meta-analyses, however, indicate modest effects compared to treatment as usual or comparison therapies such as supportive counselling. Here, we seek to identify factors impacting the effectiveness of CBTp, and avenues for future psychotherapy research that may improve outcomes. Method We outline two recent umbrella reviews and discuss factors likely to impact the effectiveness of CBTp. Results Modest effect sizes from meta-analyses mask heterogeneous outcomes, with some people benefiting and others possibly being harmed by therapy. Common factors such as the therapeutic alliance play an important role in determining outcomes but have been largely neglected by CBTp researchers. There is also the promise of improving outcomes by identifying and targeting the psychological mechanisms that either maintain psychotic symptoms (e.g. worry) or are causally implicated (e.g. trauma). Conclusions It is unlikely that everyone with psychosis will be equally responsive to the same therapeutic protocols. We need a new, personalised psychotherapy approach to CBTp research and practice, and can learn from research for anxiety and depression examining predictors of therapeutic response to inform treatment decisions. Precision psychological therapies informed by a combination of individual characteristics, common factors and a focus on specific mechanisms will require new research strategies and are likely to lead to improved outcomes for people with psychosis

    Negative cognition, affect, metacognition and dimensions of paranoia in people at ultra-high risk of psychosis: a multi-level modelling analysis

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    Background: Paranoia is one of the commonest symptoms of psychosis but has rarely been studied in a population at risk of developing psychosis. Based on existing theoretical models, including the proposed distinction between ‘poor me’ and ‘bad me’ paranoia, we aimed to test specific predictions about associations between negative cognition, metacognitive beliefs and negative emotions and paranoid ideation and the belief that persecution is deserved (deservedness). Method: We used data from 117 participants from the Early Detection and Intervention Evaluation for people at risk of psychosis (EDIE-2) trial of cognitive–behaviour therapy, comparing them with samples of psychiatric in-patients and healthy students from a previous study. Multi-level modelling was utilized to examine predictors of both paranoia and deservedness, with post-hoc planned comparisons conducted to test whether person-level predictor variables were associated differentially with paranoia or with deservedness. Results: Our sample of at-risk mental state participants was not as paranoid, but reported higher levels of ‘bad-me’ deservedness, compared with psychiatric in-patients. We found several predictors of paranoia and deservedness. Negative beliefs about self were related to deservedness but not paranoia, whereas negative beliefs about others were positively related to paranoia but negatively with deservedness. Both depression and negative metacognitive beliefs about paranoid thinking were specifically related to paranoia but not deservedness. Conclusions: This study provides evidence for the role of negative cognition, metacognition and negative affect in the development of paranoid beliefs, which has implications for psychological interventions and our understanding of psychosis

    Identifying the bridge between depression and mania: a machine learning and network approach to bipolar disorder

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    Objectives Although the cyclic nature of bipolarity is almost by definition a network system, no research to date has attempted to scrutinize the relationship of the two bipolar poles using network psychometrics. We used state-of-the-art network and machine learning methodologies to identify symptoms, as well as relations thereof, that bridge depression and mania. Methods Observational study that used mental health data (12 symptoms for depression and 12 for mania) from a large, representative Canadian sample (the Canadian Community Health Survey of 2002). Complete data (N = 36,557; 54.6% female) were analysed using network psychometrics, in conjunction with a random forest algorithm, to examine the bidirectional interplay of depressive and manic symptoms. Results Centrality analyses pointed to symptoms relating to emotionality and hyperactivity as being the most central aspects of depression and mania, respectively. The two syndromes were spatially segregated in the bipolar model and four symptoms appeared crucial in bridging them: sleep disturbances (insomnia and hypersomnia), anhedonia, suicidal ideation, and impulsivity. Our machine learning algorithm validated the clinical utility of central and bridge symptoms (in the prediction of lifetime episodes of mania and depression), and suggested that centrality, but not bridge, metrics map almost perfectly onto a data-driven measure of diagnostic utility. Conclusions Our results replicate key findings from past network studies on bipolar disorder, but also extend them by highlighting symptoms that bridge the two bipolar poles, while also demonstrating their clinical utility. If replicated, these endophenotypes could prove fruitful targets for prevention/intervention strategies for bipolar disorders

    Childhood maltreatment and problematic social media use: The role of attachment and depression

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    Childhood maltreatment is associated with many maladaptive outcomes. This study sought to examine the association between childhood maltreatment and problematic social media use using a cross-sectional sample of young adults aged 17–25 years (n = 1029). Specifically, we studied whether the relationship is mediated through (i) attachment anxiety, (ii) attachment avoidance, or (iii) both attachment dimensions operating in series with depressive symptoms. Results revealed that a history of childhood maltreatment was significantly associated with more problematic social media use. Both anxious and avoidant attachment dimensions independently mediated the relationship between childhood maltreatment and problematic use of social media, but in opposing directions. Avoidant attachment was associated with less problematic social media use, whilst anxious attachment was associated with more problematic social media use. Avoidant attachment and depressive symptoms in series accounted for part of the relationship between childhood maltreatment and problematic social media use. Anxious attachment and depressive symptoms in series fully mediated the relationship between childhood maltreatment and problematic social media use. The results suggest that childhood maltreatment may influence social media use directly, but also indirectly. People experiencing depressive symptoms may overuse social media in an attempt to alleviate their distress. However, causality cannot be established with the current design
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