559 research outputs found

    Human Like Adaptation of Force and Impedance in Stable and Unstable Tasks

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    Abstract—This paper presents a novel human-like learning con-troller to interact with unknown environments. Strictly derived from the minimization of instability, motion error, and effort, the controller compensates for the disturbance in the environment in interaction tasks by adapting feedforward force and impedance. In contrast with conventional learning controllers, the new controller can deal with unstable situations that are typical of tool use and gradually acquire a desired stability margin. Simulations show that this controller is a good model of human motor adaptation. Robotic implementations further demonstrate its capabilities to optimally adapt interaction with dynamic environments and humans in joint torque controlled robots and variable impedance actuators, with-out requiring interaction force sensing. Index Terms—Feedforward force, human motor control, impedance, robotic control. I

    Acupuncture and bee venom therapy in the chronic low back pain: A short review

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    Background: Many pharmacological and nonpharmacologic therapies are available for the treatment of the low back pain (LBP). Despite medications are the most frequently prescribed therapy for LBP, the use of various complementary medicine techniques is increasing. The paper summarizes the latest evidence on the treatment of musculoskeletal conditions (with special focus on chronic LBP) by using acupuncture and bee venom therapy (BVT).Methodology: The overview is based on English-language studies and articles found by searches of Medline over more than last 10 years. All the paper found that refer to LBP and at least one of the analyzed therapies have been taken into account.Results: The mechanism of action, efficiency, harms, toxicity and contraindications are highlighted for the two therapies. The literature on these topics is extensive and controversial. There are trials in favour of using the two complementary therapies for rheumatic diseases, as well trials arguing that the observed analgesic effects are related to a strong placebo response.Conclusions: The choice of using acupuncture and BVT for chronic LBP depends on various factors related to patient features and preferences, but nowadays an increased attention and support has to be noted.Key words: Chronic low back pain, Acupuncture, Bee venom therapy

    Association phenomena in quaternized polysulfones/solvent/nonsolvent systems

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    Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.Theoretical and experimental aspects on association phenomena generated by hydrogen bonding, dispersive and electrostatic interactions in ternary systems consisting of a proton-donor solvent (N,N-dimethylformamide or methanol), a proton-acceptor solvent (water), and a proton-acceptor polymer (polysulfone with different alkyl side chains), are investigated. In this context, binary and ternary thermodynamic interaction parameters are corrected on the basis of different association constants. Numerical values for these constants were evaluated as a function of the system composition, by mathematical simulations. As a result, mathematical simulations allow a good theoretical description of the preferential adsorption in agreement with experimental data.dc201

    Evidence for variation in the effective population size of animal mitochondrial DNA

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    Background: It has recently been shown that levels of diversity in mitochondrial DNA are remarkably constant across animals of diverse census population sizes and ecologies, which has led to the suggestion that the effective population of mitochondrial DNA may be relatively constant. Results: Here we present several lines of evidence that suggest, to the contrary, that the effective population size of mtDNA does vary, and that the variation can be substantial. First, we show that levels of mitochondrial and nuclear diversity are correlated within all groups of animals we surveyed. Second, we show that the effectiveness of selection on non-synonymous mutations, as measured by the ratio of the numbers of non-synonymous and synonymous polymorphisms, is negatively correlated to levels of mitochondrial diversity. Finally, we estimate the effective population size of mitochondrial DNA in selected mammalian groups and show that it varies by at least an order of magnitude. Conclusions: We conclude that there is variation in the effective population size of mitochondria. Furthermore we suggest that the relative constancy of DNA diversity may be due to a negative correlation between the effective population size and the mutation rate per generation

    Helmholtz's inverse problem of the discrete calculus of variations

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    International audienceWe derive the discrete version of the classical Helmholtz's condition. Precisely, we state a theorem characterizing second order finite differences equations admitting a Lagrangian formulation. Moreover, in the affirmative case, we provide the class of all possible Lagrangian formulations

    Shifts in Soil Bacterial Communities as a Function of Carbon Source Used During Anaerobic Soil Disinfestation

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    Anaerobic soil disinfestation (ASD) is an organic amendment-based management practice for controlling soil-borne plant pathogens. Pathogen suppression appears to be carbon source-dependent and mediated by bacteria that proliferate and produce volatile organic compounds, as well as physico-chemical changes (i.e., elevated temperature, lowered redox potential and pH, release of metal ions) in soil. ASD is under study for adoption in tree crops as a replacement for chemical-fumigation, but its widespread use is limited by incomplete understanding of its suppression mechanisms and high economic costs. The carbon substrate is one component of the ASD process that can be optimized to enhance effectiveness and affordability. While rice bran is currently the standard carbon source used for ASD, we identified three alternative substrates (molasses, mustard seed meal, and tomato pomace) that are similar in efficacy to rice bran at generating and sustaining soil anoxia and reducing populations of introduced plant pathogens. Here, we used replicated ASD field trials to determine if rice bran and the alternative carbon substrates would elicit similar soil bacterial communities (characterized via amplicon sequencing of the 16S rRNA gene v4 region) and to assess if any observed community shifts were consistent across repeated trials. We found significant, but minimal differences in community composition between ASD carbon treatments (F4, 30 = 2.80, P < 0.001, R2 = 0.22) and trials (F1, 30 = 5.24, P < 0.001, R2 = 0.10). In both trials, the abundances of Bacteroidales, Clostridiales, Selenomonadales, and Enterobacteriales increased significantly (>5 log2 fold change) in all ASD treatments compared to untreated controls. A group of shared core genera belonging to the Clostridiales and Selenomonadales were identified in both trials and constituted 22.6 and 21.5% of the communities. Bacterial taxa that were most responsive to ASD treatments had the genomic potential for denitrification, nitrogen fixation, and fermentation reactions that produce organic acids (such as acetate and butyrate) known to inhibit in vitro growth of plant pathogens based on predicted metagenomes. Together, these results indicate that reproducible and effective implementation of ASD is achievable with alternative carbon substrates to rice bran

    Direct and Inverse Variational Problems on Time Scales: A Survey

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    We deal with direct and inverse problems of the calculus of variations on arbitrary time scales. Firstly, using the Euler-Lagrange equation and the strengthened Legendre condition, we give a general form for a variational functional to attain a local minimum at a given point of the vector space. Furthermore, we provide a necessary condition for a dynamic integro-differential equation to be an Euler-Lagrange equation (Helmholtz's problem of the calculus of variations on time scales). New and interesting results for the discrete and quantum settings are obtained as particular cases. Finally, we consider very general problems of the calculus of variations given by the composition of a certain scalar function with delta and nabla integrals of a vector valued field.Comment: This is a preprint of a paper whose final and definite form will be published in the Springer Volume 'Modeling, Dynamics, Optimization and Bioeconomics II', Edited by A. A. Pinto and D. Zilberman (Eds.), Springer Proceedings in Mathematics & Statistics. Submitted 03/Sept/2014; Accepted, after a revision, 19/Jan/201

    An interrupted time series analysis to determine the effect of an electronic health record-based intervention on appropriate screening for type 2 diabetes in urban primary care clinics in New York city

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    OBJECTIVE To determine the impact of a health system–wide primary care diabetes management system, which included targeted guidelines for type 2 diabetes (T2DM) and prediabetes (dysglycemia) screening, on detection of previously undiagnosed dysglycemia cases. RESEARCH DESIGN AND METHODS Intervention included electronic health record (EHR)–based decision support and standardized providers and staff training for using the American Diabetes Association guidelines for dysglycemia screening. Using EHR data, we identified 40,456 adults without T2DM or recent screening with a face-to-face visit (March 2011–December 2013) in five urban clinics. Interrupted time series analyses examined the impact of the intervention on trends in three outcomes: 1) monthly proportion of eligible patients receiving dysglycemia testing, 2) two negative comparison conditions (dysglycemia testing among ineligible patients and cholesterol screening), and 3) yield of undiagnosed dysglycemia among those tested. RESULTS Baseline monthly proportion of eligible patients receiving testing was 7.4–10.4%. After the intervention, screening doubled (mean increase + 11.0% [95% CI 9.0, 13.0], proportion range 18.6–25.3%). The proportion of ineligible patients tested also increased (+5.0% [95% CI 3.0, 8.0]) with no concurrent change in cholesterol testing (+0% [95% CI 20.02, 0.05]). About 59% of test results in eligible patients showed dysglycemia both before and after the intervention. CONCLUSIONS Implementation of a policy for systematic dysglycemia screening including formal training and EHR templates in urban academic primary care clinics resulted in a doubling of appropriate testing and the number of patients who could be targeted for treatment to prevent or delay T2DM
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