74 research outputs found

    An influence based error identification for kinematics calibration of serial robotic manipulators

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    In serial robotic manipulators, due to the nature of the coupling of links, the influence of errors in joint parameters on pose accuracy varies with the configuration. Kinematics parameter’s error identification in the standard kinematics calibration has been configuration independent which does not consider the influence of kinematics parameter on robot tool pose accuracy for a given configuration. Mutually dependent joint parameter errors cannot be identified at the same time, and hence error of one parameter in each pair is identified. In a pair of mutually dependent joint parameters, the effect of error in one parameter on positional error can be more than the other one depending on the configuration. Therefore, the error detection may be incorrect if the influence of joint parameters is ignored during the error identification. This research analyses the configuration dependent influences of kinematics parameters error on pose accuracy of a robot. Based on the effect of kinematics parameters, the errors in the kinematics parameters are identified. Kinematics model of the robot is composed of the modified DH method and an improved DH method to avoid the limitations of the original DH method. First, the robot is calibrated to identify errors in 17 kinematics parameters conventionally, and then errors are detected based on the proposed method.D. A. Patel, T. F. Lu and L. Che

    The Transfer of Evolved Artificial Immune System Behaviours between Small and Large Scale Robotic Platforms

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    This paper demonstrates that a set of behaviours evolved in simulation on a miniature robot (epuck) can be transferred to a much larger scale platform (a virtual Pioneer P3-DX) that also differs in shape, sensor type, sensor configuration and programming interface. The chosen architecture uses a reinforcement learning-assisted genetic algorithm to evolve the epuck behaviours, which are encoded as a genetic sequence. This sequence is then used by the Pioneers as part of an adaptive, idiotypic artificial immune system (AIS) control architecture. Testing in three different simulated worlds shows that the Pioneer can use these behaviours to navigate and solve object-tracking tasks successfully, as long as its adaptive AIS mechanism is in place.Comment: 12 pages, 3 figures, 2 tables, 9th International Conference on Artificial Evolution (EA 09)

    Go4it; study design of a randomised controlled trial and economic evaluation of a multidisciplinary group intervention for obese adolescents for prevention of diabetes mellitus type 2

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    <p>Abstract</p> <p>Background</p> <p>In the Netherlands, the first adolescents with diabetes mellitus type 2 as a result of obesity have recently been diagnosed. Therefore, it is very important that programs aiming at the prevention of type 2 diabetes of obese adolescents are developed and evaluated.</p> <p>Methods</p> <p>Go4it is a multidisciplinary group treatment that focuses on: 1) increasing awareness of the current dietary and physical activity behaviour (i.e. energy balance behaviour), 2) improving diet, 3) decreasing sedentary behaviour, 4) increasing levels of physical activity, and 5) coping with difficult situations. Go4it consists of 7 sessions with an interval of 2–3 weeks.</p> <p>The effectiveness of the multidisciplinary group treatment compared with usual care (i.e. referral to a dietician) was evaluated in a randomised controlled trial. We examined effects on BMI(sds), body composition, energy expenditure, glucose tolerance and insulin resistance (primary outcome measure), as well as dietary and physical activity behaviour and quality of life. An economic evaluation from a societal perspective was conducted alongside the randomised trial to evaluate the cost-effectiveness of the multidisciplinary treatment program vs. usual care.</p> <p>Discussion</p> <p>In this paper we described a multidisciplinary treatment program (Go4it) for obese adolescents and the design of a randomised controlled trial and economic evaluation to evaluate its effectiveness and cost-effectiveness.</p> <p>Trial registration</p> <p>Netherlands Trial Register (ISRCTN27626398).</p

    Evaluation of an online interactive Diabetes Needs Assessment Tool (DNAT) versus online self-directed learning: a randomised controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Methods for the dissemination, understanding and implementation of clinical guidelines need to be examined for their effectiveness to help doctors integrate guidelines into practice. The objective of this randomised controlled trial was to evaluate the effectiveness of an interactive online Diabetes Needs Assessment Tool (DNAT) (which constructs an e-learning curriculum based on individually identified knowledge gaps), compared with self-directed e-learning of diabetes guidelines.</p> <p>Methods</p> <p>Health professionals were randomised to a 4-month learning period and either given access to diabetes learning modules alone (control group) or DNAT plus learning modules (intervention group). Participants completed knowledge tests before and after learning (primary outcome), and surveys to assess the acceptability of the learning and changes to clinical practice (secondary outcomes).</p> <p>Results</p> <p>Sixty four percent (677/1054) of participants completed both knowledge tests. The proportion of nurses (5.4%) was too small for meaningful analysis so they were excluded. For the 650 doctors completing both tests, mean (SD) knowledge scores increased from 47.4% (12.6) to 66.8% (11.5) [intervention group (n = 321, 64%)] and 47.3% (12.9) to 67.8% (10.8) [control group (n = 329, 66%)], (ANCOVA p = 0.186). Both groups were satisfied with the usability and usefulness of the learning materials. Seventy seven percent (218/284) of the intervention group reported combining the DNAT with the recommended reading materials was "<it>very useful"/"useful"</it>. The majority in both groups (184/287, 64.1% intervention group and 206/299, 68.9% control group) [95% CI for the difference (-2.8 to 12.4)] reported integrating the learning into their clinical practice.</p> <p>Conclusions</p> <p>Both groups experienced a similar and significant improvement in knowledge. The learning materials were acceptable and participants incorporated the acquired knowledge into practice.</p> <p>Trial registration</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/ISRCTN67215088">ISRCTN67215088</a></p

    Effect of solution saturation state and temperature on diopside dissolution

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    Steady-state dissolution rates of diopside are measured as a function of solution saturation state using a titanium flow-through reactor at pH 7.5 and temperature ranging from 125 to 175°C. Diopside dissolved stoichiometrically under all experimental conditions and rates were not dependent on sample history. At each temperature, rates continuously decreased by two orders of magnitude as equilibrium was approached and did not exhibit a dissolution plateau of constant rates at high degrees of undersaturation. The variation of diopside dissolution rates with solution saturation can be described equally well with a ion exchange model based on transition state theory or pit nucleation model based on crystal growth/dissolution theory from 125 to 175°C. At 175°C, both models over predict dissolution rates by two orders of magnitude indicating that a secondary phase precipitated in the experiments. The ion exchange model assumes the formation of a Si-rich, Mg-deficient precursor complex. Lack of dependence of rates on steady-state aqueous calcium concentration supports the formation of such a complex, which is formed by exchange of protons for magnesium ions at the surface. Fit to the experimental data yields [Formula: see text] where the Mg-H exchange coefficient, n = 1.39, the apparent activation energy, E(a )= 332 kJ mol(-1), and the apparent rate constant, k = 10(41.2 )mol diopside cm(-2 )s(-1). Fits to the data with the pit nucleation model suggest that diopside dissolution proceeds through retreat of steps developed by nucleation of pits created homogeneously at the mineral surface or at defect sites, where homogeneous nucleation occurs at lower degrees of saturation than defect-assisted nucleation. Rate expressions for each mechanism (i) were fit to [Formula: see text] where the step edge energy (α) for homogeneously nucleated pits were higher (275 to 65 mJ m(-2)) than the pits nucleated at defects (39 to 65 mJ m(-2)) and the activation energy associated with the temperature dependence of site density and the kinetic coefficient for homogeneously nucleated pits (E(b-homogeneous )= 2.59 × 10(-16 )mJ K(-1)) were lower than the pits nucleated at defects (E(b-defect assisted )= 8.44 × 10(-16 )mJ K(-1))

    A cluster randomized trial to improve adherence to evidence-based guidelines on diabetes and reduce clinical inertia in primary care physicians in Belgium: study protocol [NTR 1369]

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    Contains fulltext : 70617.pdf (publisher's version ) (Open Access)ABSTRACT: BACKGROUND: Most quality improvement programs in diabetes care incorporate aspects of clinician education, performance feedback, patient education, care management, and diabetes care teams to support primary care physicians. Few studies have applied all of these dimensions to address clinical inertia. AIM: To evaluate interventions to improve adherence to evidence-based guidelines for diabetes and reduce clinical inertia in primary care physicians. DESIGN: Two-arm cluster randomized controlled trial. PARTICIPANTS: Primary care physicians in Belgium. INTERVENTIONS: Primary care physicians will be randomly allocated to 'Usual' (UQIP) or 'Advanced' (AQIP) Quality Improvement Programs. Physicians in the UQIP will receive interventions addressing the main physician, patient, and office system factors that contribute to clinical inertia. Physicians in the AQIP will receive additional interventions that focus on sustainable behavior changes in patients and providers. OUTCOMES: Primary endpoints are the proportions of patients within targets for three clinical outcomes: 1) glycosylated hemoglobin < 7%; 2) systolic blood pressure differences </=130 mmHg; and 3) low density lipoprotein/cholesterol < 100 mg/dl. Secondary endpoints are individual improvements in 12 validated parameters: glycosylated hemoglobin, low and high density lipoprotein/cholesterol, total cholesterol, systolic blood pressure, diastolic blood pressure, weight, physical exercise, healthy diet, smoking status, and statin and anti-platelet therapy. PRIMARY AND SECONDARY ANALYSIS: Statistical analyses will be performed using an intent-to-treat approach with a multilevel model. Linear and generalized linear mixed models will be used to account for the clustered nature of the data, i.e., patients clustered withinimary care physicians, and repeated assessments clustered within patients. To compare patient characteristics at baseline and between the intervention arms, the generalized estimating equations (GEE) approach will be used, taking the clustered nature of the data within physicians into account. We will also use the GEE approach to test for differences in evolution of the primary and secondary endpoints for all patients, and for patients in the two interventions arms, accounting for within-patient clustering. TRIAL REGISTRATION: number: NTR 1369

    Implementing a guideline for the treatment of type 2 diabetics: results of a Cluster- Randomized Controlled Trial (C-RCT)

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    <p>Abstract</p> <p>Background</p> <p>In Italy many diabetics still lack adequate care in general practice. We assessed the effectiveness of different strategies for the implementation of an evidence-based guideline for the management of non-complicated type 2 diabetes among General Practitioners (GPs) of Lazio region.</p> <p>Methods</p> <p>Three-arm cluster-randomised controlled trial with GPs as units of randomisation (clusters). 252 GPs were randomised either to an active strategy (training module with administration of the guideline), or to a passive dissemination (administration of the guideline only), or to usual care (control). Data on prescriptions of tests and drugs were collected by existing information systems, whereas patients' data came from GPs' databases. Process outcomes were measured at the cluster level one year after the intervention. Primary outcomes concerned the measurement of glycosilated haemoglobin and the commissioning of micro- and macrovascular complications assessment tests. In order to assess the physicians' drug prescribing behaviour secondary outcomes were also calculated.</p> <p>Results</p> <p>GPs identified 6395 uncomplicated type 2 patients with a high prevalence of cardiovascular risk factors. Data on GPs baseline performance show low proportions of glycosilated haemoglobin assessments. Results of the C-RCT analysis indicate that the active implementation strategy was ineffective relating to all primary outcomes (respectively, OR 1.06 [95% IC: 0.76–1.46]; OR 1.07 [95% IC: 0.80–1.43]; OR 1.4 [95% IC:0.91–2.16]. Similarly, passive dissemination of the guideline showed no effect.</p> <p>Conclusion</p> <p>In our region compliance of GPs with guidelines was not enhanced by a structured learning programme. Implementation through organizational measures appears to be essential to induce behavioural changes.</p> <p>Trial registration</p> <p>ISRCTN80116232</p

    Promotion of a healthy lifestyle among 5-year-old overweight children: Health behavior outcomes of the 'Be active, eat right' study

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    Background: This study evaluates the effects of an intervention performed by youth health care professionals on child health behaviors. The intervention consisted of offering healthy lifestyle counseling to parents of overweight (not obese) 5-year-old children. Effects of the intervention on the child having breakfast, drinking sweet beverages, watching television and playing outside were evaluated. Methods. Data were collected with the 'Be active, eat right' study, a cluster randomized controlled trial among nine youth health care centers in the Netherlands. Parents of overweight children received lifestyle counseling according to the intervention protocol in the intervention condition (n = 349) and usual care in the control condition (n = 288). Parents completed questionnaires regarding demographic characteristics, health behaviors and the home environment at baseline and at 2-year follow-up. Cluster adjusted regression models were applied; interaction terms were explored. Results: The population for analysis consisted of 38.1% boys; mean age 5.8 [sd 0.4] years; mean BMI SDS 1.9 [sd 0.4]. There were no significant differences in the number of minutes of outside play or television viewing a day between children in the intervention and the control condition. Also, the odds ratio for having breakfast daily or drinking two or less glasses of sweet beverages a day showed no significant differences between the two conditions. Additional analyses showed that the odds ratio for drinking less than two glasses of sweet beverages at follow-up compared with baseline was significantly higher for children in both the intervention (p < 0.001) and the control condition (p = 0.029). Conclusions: Comparison of the children in the two conditions showed that the intervention does not contribute to a change in health behaviors. Further studies are needed to investigate opportunities to adjust the intervention protocol, such as integration of elements in the regular well-child visit. The intervention protocol for youth health care may become part of a broader approach to tackle childhood overweight and obesity. Trial registration. Current Controlled Trials ISRCTN04965410

    Quality of interaction between primary health-care providers and patients with type 2 diabetes in Muscat, Oman: an observational study

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    BACKGROUND: A good patient-physician interaction is particularly important in chronic diseases like diabetes. There are so far no published data regarding the interaction between the primary health-care providers and patients with type 2 diabetes in Oman, where diabetes is a major and growing health problem. This study aimed at exploring how health-care providers interact with patients with type 2 diabetes at primary health-care level in Muscat, Oman, focusing on the consultation environment, and some aspects of care and information. METHODS: Direct observations of 90 consultations between 23 doctors and 13 diabetes nurses concerned with diabetes management during their consultations with type 2 diabetes patients in six primary health-care centres in the Muscat region, using checklists developed from the National Diabetes Guidelines. Consultations were assessed as optimal if more than 75% of observed aspects were fulfilled and sub-optimal if less than 50% were fulfilled. RESULTS: Overall 52% of the doctors' consultations were not optimal. Some important aspects for a positive consultation environment were fulfilled in only about half of the doctors' consultations: ensuring privacy of consultation (49%), eye contact (49%), good attention (52%), encouraging asking questions (47%), and emphasizing on the patients' understanding of the provided information (52%). The doctors enquired about adverse effects of anti-diabetes drugs in less than 10% of consultations. The quality of the nurses' consultations was sub-optimal in about 75% of 85 consultations regarding aspects of consultation environment, care and information. CONCLUSION: The performance of the primary health-care doctors and diabetes nurses needs to be improved. The role of the diabetes nurses and the teamwork should be enhanced. We suggest a multidisciplinary team approach, training and education to the providers to upgrade their skills regarding communication and care. Barriers to compliance with the guidelines need to be further explored. Improving the work situation mainly for the diabetes nurses and further improvement in the organizational efficiency of diabetes services such as lowering the number of patients in diabetes clinic, are suggested

    Calculation of the visible-UV absorption spectra of hydrogen sulfide, bisulfide, polysulfides, and As and Sb sulfides, in aqueous solution

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    Recently we showed that visible-UV spectra in aqueous solution can be accurately calculated for arsenic (III) bisulfides, such as As(SH)(3), As(SH)(2)S(- )and their oligomers. The calculated lowest energy transitions for these species were diagnostic of their protonation and oligomerization state. We here extend these studies to As and Sb oxidation state III and v sulfides and to polysulfides S(n)(2-), n = 2–6, the bisulfide anion, SH(-), hydrogen sulfide, H(2)S and the sulfanes, S(n)H(2), n = 2–5. Many of these calculations are more difficult than those performed for the As(iii) bisulfides, since the As and Sb(v) species are more acidic and therefore exist as highly charged anions in neutral and basic solutions. In general, small and/or highly charged anions are more difficult to describe computationally than larger, monovalent anions or neutral molecules. We have used both Hartree-Fock based (CI Singles and Time-Dependent HF) and density functional based (TD B3LYP) techniques for the calculations of absorption energy and intensity and have used both explicit water molecules and a polarizable continuum to describe the effects of hydration. We correctly reproduce the general trends observed experimentally, with absorption energies increasing from polysulfides to As, Sb sulfides to SH(- )to H(2)S. As and Sb(v) species, both monomers and dimers, also absorb at characteristically higher energies than do the analogous As and Sb(III)species. There is also a small reduction in absorption energy from monomeric to dimeric species, for both As and Sb III and v. The polysufides, on the other hand, show no simple systematic changes in UV spectra with chain length, n, or with protonation state. Our results indicate that for the As and Sb sulfides, the oxidation state, degree of protonation and degree of oligomerization can all be determined from the visible-UV absorption spectrum. We have also calculated the aqueous phase energetics for the reaction of S(8 )with SH(- )to produce the polysulfides, S(n)H(-), n = 2–6. Our results are in excellent agreement with available experimental data, and support the existence of a S(6 )species
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