Learning feedforward controller for a mobile robot vehicle

This paper describes the design and realisation of an on-line learning posetracking controller for a three-wheeled mobile robot vehicle. The controller consists of two components. The first is a constant-gain feedback component, designed on the basis of a second-order model. The second is a learning feedforward component, containing a single-layer neural network, that generates a control contribution on the basis of the desired trajectory of the vehicle. The neural network uses B-spline basis functions, enabling a computationally fast implementation and fast learning. The resulting control system is able to correct for errors due to parameter mismatches and classes of structural errors in the model used for the controller design. After sufficient learning, an existing static gain controller designed on the basis of an extensive model has been outperformed in terms of tracking accuracy

Adaptive neural network control of fes-induced cyclical lower leg movements

As a first step to the control of paraplegic gait by functional electrical stimulation (FES), the control of the swinging lower leg is being studied. This paper deals with a neural control system, that has been developed for this case. The control system has been tested for a model of the swinging lower leg using computer simulations. The neural controller was trained by supervised learning (SL) and by backpropagation through time (BTT). The performance of the controller with random initial weights was poor after training with BTT and fair after SL. BTT training of the neural controller with weights, which had been initialized by SL, resulted in good control. Training with BTT thus improved the performance of the controller that initially had been trained by SL. An adaptive neural control system based on BTT has been proposed and partially tested. The controller adapted relatively fast to the change of an important model parameter

Living positive: eHealth for people with HIV and depressive symptoms

This dissertation contains the results of an RCT into the effectiveness of an online self-help intervention for people living with HIV (PLWH) and depressive symptoms. Many PLWH suffer from depressive symptoms. Online interventions to treat depression may have benefits, such as less perceived stigma, a large reach and high accessibility. The online self-help intervention that we investigated is based on cognitive behavioral therapy and contains 4 components: stimulating activities, relaxation exercises, changing negative thoughts and goal attainment. Two meta-analyses were conducted and the results point to the effectiveness of psychosocial interventions for PLWH to improve depressive symptoms, anxiety symptoms, quality of life, psychological well-being, and medication adherence. The most important result of the RCT was that the intervention together with telephone coaching is effective in reducing depressive symptoms, compared to an attention-only control group. It was also found that the intervention may be effective for all PLWH, regardless of certain baseline characteristics. Furthermore, behavioral activation and goal reengagement were found to be mediators of the intervention effect. Also, the intervention is likely to be cost-effective compared to attention only. As eHealth interventions have benefits compared to face-to-face interventions, they should be more widely implemented in the mental healthcare for PLWH.AidsfondsStress and Psychopatholog

Rte-1, a retrotransposon-like element in Caenorhabditis elegans

AbstractWe have characterized a retrotransposon-like element (Rte-1) in C. elegans. It was identified while we were sequencing the pim related kinase-1 (prk-1) gene. The element is 3,298 bp long and flanked by a 200 bp direct repeat. 95 bp of the direct repeat are present in the coding region of prk-1. Rte-1 contains an open reading frame, in the opposite orientation of prk-1, potentially encoding 625 amino acids, with similarity to reverse transcriptases. The element is most similar to members of the non-LTR group of retrotransposable elements. There is weak homology of the predicted amino acid sequence of Rte-1 to several reverse transcriptase-like genes identified by the C. elegans genome sequencing consortium, suggesting that there may be a large family of these elements. Southern blots indicate that there are approximately 10–15 additional Rte-1 elements in the C. elegans Bristol N2 genome and a similar number is found in the genomes of two other geographically distinct strains. The insertion pattern of Rte-1 is polymorphic between these strains

Assessing excellence in translational cancer research: a consensus based framework

Background: It takes several years on average to translate basic research findings into clinical research and eventually deliver patient benefits. An expert-based excellence assessment can help improve this process by: identifying high performing Comprehensive Cancer Centres; best practices in translational cancer research; improving the quality and efficiency of the translational cancer research process. This can help build networks of excellent Centres by aiding focused partnerships. In this paper we report on a consensus building exercise that was undertaken to construct an excellence assessment framework for translational cancer research in Europe. Methods: We used mixed methods to reach consensus: a systematic review of existing translational research models critically appraised for suitability in performance assessment of Cancer Centres; a survey among European stakeholders (researchers, clinicians, patient representatives and managers) to score a list of potential excellence criteria, a focus group with selected representatives of survey participants to review and rescore the excellence criteria; an expert group meeting to refine the list; an open validation round with stakeholders and a critical review of the emerging framework by an independent body: a committee formed by the European Academy of Cancer Sciences. Results: The resulting excellence assessment framework has 18 criteria categorized in 6 themes. Each criterion has a number of questions/sub-criteria. Stakeholders favoured using qualitative excellence criteria to evaluate the translational research “process” rather than quantitative criteria or judging only the outputs. Examples of criteria include checking if the Centre has mechanisms that can be rated as excellent for: involvement of basic researchers and clinicians in translational research (quality of supervision and incentives provided to clinicians to do a PhD in translational research) and well designed clinical trials based on ground-breaking concepts (innovative patient stratification, substantial fraction of phase I/II trials, investigator-initiated trials). Critically, the framework supports reduced bureaucracy by building on existing European evaluation systems. Conclusions: The excellence framework is the product of an intense stakeholder consensus building exercise. It will be piloted during an expert peer review/site visit of at least three European Comprehensive Cancer Centres. The findings regarding content, governance and implementation can have relevance for other clinical and research fields

mut-7 of C. elegans, Required for Transposon Silencing and RNA Interference, Is a Homolog of Werner Syndrome Helicase and RNaseD

AbstractWhile all known natural isolates of C. elegans contain multiple copies of the Tc1 transposon, which are active in the soma, Tc1 transposition is fully silenced in the germline of many strains. We mutagenized one such silenced strain and isolated mutants in which Tc1 had been activated in the germline (“mutators”). Interestingly, many other transposons of unrelated sequence had also become active. Most of these mutants are resistant to RNA interference (RNAi). We found one of the mutated genes, mut-7, to encode a protein with homology to RNaseD. This provides support for the notion that RNAi works by dsRNA-directed, enzymatic RNA degradation. We propose a model in which MUT-7, guided by transposon-derived dsRNA, represses transposition by degrading transposon-specific messengers, thus preventing transposase production and transposition

Long‑term effectiveness of an online self‑help intervention for people with HIV and depressive symptoms

Stress and Psychopatholog

Psychosocial interventions enhance HIV medication adherence: a systematic review and meta-analysis

About 40 per cent of people living with HIV do not sufficiently adhere to their medication regimen, which adversely affects their health. The current meta-analysis investigated the effect of psychosocial interventions on medication adherence in people living with HIV. Databases were systematically searched, resulting in 43 included randomized controlled trials. Study and intervention characteristics were investigated as moderators. The overall effect size indicates a small to moderate positive effect (Hedges' g = 0.37) of psychosocial interventions on medication adherence in people living with HIV. No evidence for publication bias was found. This meta-analysis study concludes that various psychosocial interventions can improve medication adherence and thereby the health of people living with HIV.Stress and Psychopatholog

A systematic review on the use of mHealth to increase physical activity in older people

Stress and Psychopatholog