394 research outputs found

    Comments on "Particle Markov chain Monte Carlo" by C. Andrieu, A. Doucet, and R. Hollenstein

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    This is the compilation of our comments submitted to the Journal of the Royal Statistical Society, Series B, to be published within the discussion of the Read Paper of Andrieu, Doucet and Hollenstein.Comment: 7 pages, 4 figure

    Reflexive obstacle avoidance for kinematically-redundant manipulators

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    Dexterous telerobots incorporating 17 or more degrees of freedom operating under coordinated, sensor-driven computer control will play important roles in future space operations. They will also be used on Earth in assignments like fire fighting, construction and battlefield support. A real time, reflexive obstacle avoidance system, seen as a functional requirement for such massively redundant manipulators, was developed using arm-mounted proximity sensors to control manipulator pose. The project involved a review and analysis of alternative proximity sensor technologies for space applications, the development of a general-purpose algorithm for synthesizing sensor inputs, and the implementation of a prototypical system for demonstration and testing. A 7 degree of freedom Robotics Research K-2107HR manipulator was outfitted with ultrasonic proximity sensors as a testbed, and Robotics Research's standard redundant motion control algorithm was modified such that an object detected by sensor arrays located at the elbow effectively applies a force to the manipulator elbow, normal to the axis. The arm is repelled by objects detected by the sensors, causing the robot to steer around objects in the workspace automatically while continuing to move its tool along the commanded path without interruption. The mathematical approach formulated for synthesizing sensor inputs can be employed for redundant robots of any kinematic configuration

    S.E.O.: a Biblioteconomia no Brasil

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    O status dos bibliotecários é baixo, apesar de a profissão ser regulamentada por lei. A Biblioteconomia é uma profissão predominantemente feminina e os salários são reduzidos, embora venham melhorando, tanto quanto vem aumentando o ingresso de homens em bibliotecas e centros de documentação. A Documentação goza de mais prestigio do que a Biblioteconomia e as bibliotecas mais eficientes são normalmente as que desenvolvem atividades de documentação. Essas bibliotecas, em geral, são as melhores, seguidas pelas bibliotecas universitárias e públicas. A fim de melhorar o status e a eficácia da profissão como fator essencial na vida social e econômica da nação e de preparar professores capacitados é preciso que se estabeleçam cursos de pós-graduação. Uma associação nacional é necessária para influir junto ao Governo no que diz respeito à  implantação e melhoramento dos serviços bibliotecários e de documentação. Todos os bibliotecários devem apoiar a implantação de um serviço nacional de bibliotecas que seja forte e tenha amplas atribuições

    A 17 degree of freedom anthropomorphic manipulator

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    A 17 axis anthropomorphic manipulator, providing coordinated control of two seven degree of freedom arms mounted on a three degree of freedom torso-waist assembly, is presented. This massively redundant telerobot, designated the Robotics Research K/B-2017 Dexterous Manipulator, employs a modular mechanism design with joint-mounted actuators based on brushless motors and harmonic drive gear reducers. Direct joint torque control at the servo level causes these high-output joint drives to behave like direct-drive actuators, facilitating the implementation of an effective impedance control scheme. The redundant, but conservative motion control system models the manipulator as a spring-loaded linkage with viscous damping and rotary inertia at each joint. This approach allows for real time, sensor-driven control of manipulator pose using a hierarchy of competing rules, or objective functions, to avoid unplanned collisions with objects in the workplace, to produce energy-efficient, graceful motion, to increase leverage, to control effective impedance at the tool or to favor overloaded joints

    The perception and management of risk in UK office property development

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    Risk is an ever-present aspect of business, and risk taking is necessary for profit and economic progress. Speculative property development is popularly perceived as a 'risky business' yet, like other entrepreneurs, developers have opportunities to manage the risks they face; techniques include phasing and joint ventures. The associated areas of investment portfolio risk, development risk analysis and construction risk management have all been addressed by research. This article presents new knowledge about how developers perceive risks and the means they subsequently adopt to manage them. The developers of office projects across the UK were sent questionnaires by post. Respondents were asked about their perceptions of risks at the first appraisal stage and currently and about the risk management techniques that they had adopted. In-depth interviews with a selection of respondents were then used to discuss and augment the findings. Developers were most concerned about market-based risks at both stages. Concern about production-orientated risks was lower and fell significantly between the two stages. A fixed price contract was the most common risk management technique. Risk management techniques were used more often outside London and the South East. Developer type affects both the perception and management of risk. While developers do manage risk, decisions are made on the basis of professional and business experience. These findings should help development companies manage risk in a more objective and analytical way

    Malignant and Nonmalignant Gene Signatures in Squamous Head and Neck Cancer

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    Genetic events specific to the pathogenesis of malignancy can offer clues to the tumorigenesis process. The objective of this study was to identify gene alterations that differentiate tumor and nontumor lesions in squamous head and neck cancer (HNSCC). DNA from 220 primary HNSCC with concurrently present tumor and nontumor lesions from the same patient was interrogated for genomic alterations of loss or gain of copy. Conditional logistic regression dealt with tumor and non-tumor records within a patient. Of 113 genes, 53 had univariate effects (P < 0.01), of which 16 genes remained in the multivariable model with P < 0.01. The model had a C-index (ROC) of 0.93. Loss of CDKN2B and gain of BCL6, FGF3, and PTP4A3 predicted tumor. Loss of BAK1 and CCND1 and gain of STCH predicted nontumor. This highly powered model assigned alterations in 16 genes specific for malignant versus nonmalignant lesions, supporting their contribution to the pathogenesis of HNSCC as well as their potential utility as relevant targets for further evaluation as markers of early detection and progression

    Consent procedures and relationship with outcome in the Rapid Intervention with Glyceryl trinitrate in Hypertensive stroke Trial-2 (RIGHT-2)

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    Background: Obtaining consent in emergency situations is challenging. Proxy consent allows patients to be recruited when they lack capacity, a common scenario in stroke patients. The rapid intervention with glyceryl trinitrate in hypertensive stroke trial-2 (RIGHT-2) recruits patients in the pre-hospital setting within 4 hours of stroke onset. Methods: In RIGHT-2, informed or proxy consent is taken in the ambulance. A brief assessment of capacity is performed by the paramedic. Patients with capacity provide consent and in patients without capacity, proxy consent is obtained from a relative, carer or friend, or by the paramedic, witnessed by a crew member. Results: Of 879 participants enrolled into RIGHT-2 as of 15th December 2017, 468 (53.2%) participants gave their own consent; proxy consent was given by a relative/carer/friend for 325 (37%) and by a paramedic for 85 (9.7%). Participants who consented themselves were younger, had less dependency and had less severe strokes than those with proxy consent. Participants who gave their own consent had a lower rate of intracerebral haemorrhage (9% vs 16%) and a higher rate of non-stroke (20% vs 13%) as their final diagnosis than those who gave proxy consent. Consenting patients had better scores for dependency, cognition, disability and quality of life at day 90 than those recruited via proxy consent. Conclusion: Proxy consent can ensure participants are enrolled rapidly into emergency clinical trials where they may otherwise be excluded due to lack of capacity. These patients have more severe strokes and therefore poorer clinical outcomes

    Ambulance-delivered transdermal glyceryl trinitrate versus sham for ultra-acute stroke: rationale, design and protocol for the Rapid Intervention with Glyceryl trinitrate in Hypertensive stroke Trial-2 (RIGHT-2) trial (ISRCTN26986053)

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    Rationale: Vascular nitric oxide levels are low in acute stroke and donors such as glyceryl trinitrate have shown promise when administered very early after stroke. Potential mechanisms of action include augmentation of cerebral reperfusion, thrombolysis and thrombectomy, lowering blood pressure, and cytoprotection. Aim: To test the safety and efficacy of four days of transdermal glyceryl trinitrate (5 mg/day) versus sham in patients with ultra-acute presumed stroke who are recruited by paramedics prior to hospital presentation. Sample size estimates: The sample size of 850 patients will allow a shift in the modified Rankin Scale with odds ratio 0.70 (glyceryl trinitrate versus sham, ordinal logistic regression) to be detected with 90% power at 5% significance (two-sided). Design: The Rapid Intervention with Glyceryl trinitrate in Hypertensive stroke Trial-2 (RIGHT-2) is a multicentre UK prospective randomized sham-controlled outcome-blinded parallel-group trial in 850 patients with ultra-acute (4 h of onset) FAST-positive presumed stroke and systolic blood pressure 120 mmHg who present to the ambulance service following a 999 emergency call. Data collection is performed via a secure internet site with real-time data validation. Study outcomes: The primary outcome is the modified Rankin Scale measured centrally by telephone at 90 days and masked to treatment. Secondary outcomes include: blood pressure, impairment, recurrence, dysphagia, neuroimaging markers of the acute lesion including vessel patency, discharge disposition, length of stay, death, cognition, quality of life, and mood. Neuroimaging and serious adverse events are adjudicated blinded to treatment. Discussion: RIGHT-2 has recruited more than 500 participants from seven UK ambulance services. Status: Trial is ongoing. Funding: British Heart Foundation. Registration: ISRCTN26986053

    An empirical approach to selecting community-based alcohol interventions:combining research evidence, rural community views and professional opinion

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    <p>Abstract</p> <p>Background</p> <p>Given limited research evidence for community-based alcohol interventions, this study examines the intervention preferences of rural communities and alcohol professionals, and factors that influence their choices.</p> <p>Method</p> <p>Community preferences were identified by a survey of randomly selected individuals across 20 regional Australian communities. The preferences of alcohol professionals were identified by a survey of randomly selected members of the Australasian Professional Society on Alcohol and Other Drugs. To identify preferred interventions and the extent of support for them, a budget allocation exercise was embedded in both surveys, asking respondents to allocate a given budget to different interventions. Tobit regression models were estimated to identify the characteristics that explain differences in intervention preferences.</p> <p>Results</p> <p>Community respondents selected school programs most often (88.0%) and allocated it the largest proportion of funds, followed by promotion of safer drinking (71.3%), community programs (61.4%) and police enforcement of alcohol laws (60.4%). Professionals selected GP training most often (61.0%) and allocated it the largest proportion of funds, followed by school programs (36.6%), community programs (33.8%) and promotion of safer drinking (31.7%). Community views were susceptible to response bias. There were no significant predictors of professionals' preferences.</p> <p>Conclusions</p> <p>In the absence of sufficient research evidence for effective community-based alcohol interventions, rural communities and professionals both strongly support school programs, promotion of safer drinking and community programs. Rural communities also supported police enforcement of alcohol laws and professionals supported GP training. The impact of a combination of these strategies needs to be rigorously evaluated.</p
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