6,275 research outputs found

    Estimation of Kalman filter model parameters from an ensemble of tests

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    A methodology for estimating initial mean and covariance parameters in a Kalman filter model from an ensemble of nonidentical tests is presented. In addition, the problem of estimating time constants and process noise levels is addressed. Practical problems such as developing and validating inertial instrument error models from laboratory test data or developing error models of individual phases of a test are generally considered

    Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation. Volume 2, Part 2: Appendixes B, C, D and E

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    The derivation of the equations is presented, the rate control algorithm described, and simulation methodologies summarized. A set of dynamics equations that can be used recursively to calculate forces and torques acting at the joints of an n link manipulator given the manipulator joint rates are derived. The equations are valid for any n link manipulator system with any kind of joints connected in any sequence. The equations of motion for the class of manipulators consisting of n rigid links interconnected by rotary joints are derived. A technique is outlined for reducing the system of equations to eliminate contraint torques. The linearized dynamics equations for an n link manipulator system are derived. The general n link linearized equations are then applied to a two link configuration. The coordinated rate control algorithm used to compute individual joint rates when given end effector rates is described. A short discussion of simulation methodologies is presented

    Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation, volume 2, part 1. Appendix A: Software documentation

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    Documentation of the preliminary software developed as a framework for a generalized integrated robotic system simulation is presented. The program structure is composed of three major functions controlled by a program executive. The three major functions are: system definition, analysis tools, and post processing. The system definition function handles user input of system parameters and definition of the manipulator configuration. The analysis tools function handles the computational requirements of the program. The post processing function allows for more detailed study of the results of analysis tool function executions. Also documented is the manipulator joint model software to be used as the basis of the manipulator simulation which will be part of the analysis tools capability

    Are non-allergic drug reactions commonly documented as medication “allergies”? A national cohort of Veterans\u27 admissions from 2000 to 2014

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    Purpose: Adverse drug reactions (ADRs) including medication allergies are not well-described among large national cohorts. This study described the most common documented medication allergies and their reactions among a national cohort of Veterans Affairs (VA) inpatients. Methods: We evaluated inpatient admissions in any VA Medical Center from 1 January 2000 to 31 December 2014. Each admission was linked with allergy history preceding or upon admission. Individual drugs were aggregated into drug class category including: penicillins, sulfonamides, angiotensin converting enzyme (ACE) inhibitors, opiates, HMG-CoA reductase inhibitors (“statins”) and non-steroidal anti-inflammatory inhibitors (NSAID). Results were reported in aggregate and over time. Results: Approximately ~10.8 million inpatient admissions occurred from 2000 to 2014. We found the most commonly reported allergy drug classes were penicillins (13%, n = 1 410 080), opiates (9.1%, n = 984 978), ACE inhibitors (5.7%, n = 618 075) sulfonamides (5.1%, n = 558 653), NSAIDs (5.1%, n = 551 216) and statins (3.6%, n  = 391 983). Several allergy histories increased over time including opiates (6.2 to 11.2%), ACE inhibitors (1.3 to 10.2%), statins (0.3 to 7.3%) and NSAIDs (3.9 to 6.0%). Rash was the most commonly documented reaction on reports for penicillins (25.5%, n = 371 825), sulfonamides (25.6%, n = 165 954) and NSAIDs (10.3%, n = 65 741). The most common reaction for opiates was nausea/vomiting (17.9%, n = 211 864), cough/coughing for ACE inhibitors (41.0%, n = 270 537) and muscle pain/myalgia for statins (34.1%, n = 186 565). Conclusions: We report that penicillins and opiates are the most commonly documented drug allergies among VA inpatients, but other drug classes such as ACE inhibitors, statins and NSAIDs are becoming increasingly common. Clinicians also commonly document non-allergic ADRs in the allergy section such as cough or myalgia. Copyright © 2016 John Wiley & Sons, Ltd

    A pseudo-spectral approach to inverse problems in interface dynamics

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    An improved scheme for computing coupling parameters of the Kardar-Parisi-Zhang equation from a collection of successive interface profiles, is presented. The approach hinges on a spectral representation of this equation. An appropriate discretization based on a Fourier representation, is discussed as a by-product of the above scheme. Our method is first tested on profiles generated by a one-dimensional Kardar-Parisi-Zhang equation where it is shown to reproduce the input parameters very accurately. When applied to microscopic models of growth, it provides the values of the coupling parameters associated with the corresponding continuum equations. This technique favorably compares with previous methods based on real space schemes.Comment: 12 pages, 9 figures, revtex 3.0 with epsf style, to appear in Phys. Rev.

    Physician decision making in selection of second-line treatments in immune thrombocytopenia in children.

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    Immune thrombocytopenia (ITP) is an acquired autoimmune bleeding disorder which presents with isolated thrombocytopenia and risk of hemorrhage. While most children with ITP promptly recover with or without drug therapy, ITP is persistent or chronic in others. When needed, how to select second-line therapies is not clear. ICON1, conducted within the Pediatric ITP Consortium of North America (ICON), is a prospective, observational, longitudinal cohort study of 120 children from 21 centers starting second-line treatments for ITP which examined treatment decisions. Treating physicians reported reasons for selecting therapies, ranking the top three. In a propensity weighted model, the most important factors were patient/parental preference (53%) and treatment-related factors: side effect profile (58%), long-term toxicity (54%), ease of administration (46%), possibility of remission (45%), and perceived efficacy (30%). Physician, health system, and clinical factors rarely influenced decision-making. Patient/parent preferences were selected as reasons more often in chronic ITP (85.7%) than in newly diagnosed (0%) or persistent ITP (14.3%, P = .003). Splenectomy and rituximab were chosen for the possibility of inducing long-term remission (P < .001). Oral agents, such as eltrombopag and immunosuppressants, were chosen for ease of administration and expected adherence (P < .001). Physicians chose rituximab in patients with lower expected adherence (P = .017). Treatment choice showed some physician and treatment center bias. This study illustrates the complexity and many factors involved in decision-making in selecting second-line ITP treatments, given the absence of comparative trials. It highlights shared decision-making and the need for well-conducted, comparative effectiveness studies to allow for informed discussion between patients and clinicians

    Interplay of superconductivity and magnetism in strong coupling

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    A model is introduced describing the interplay between superconductivity and spin-ordering. It is characterized by on-site repulsive electron-electron interactions, causing antiferromagnetism, and nearest-neighbor attractive interactions, giving rise to d-wave superconductivity. Due to a special choice for the lattice, this model has a strong-coupling limit where the superconductivity can be described by a bosonic theory, similar to the strongly coupled negative U Hubbard model. This limit is analyzed in the present paper. A rich mean-field phase diagram is found and the leading quantum corrections to the mean-field results are calculated. The first-order line between the antiferromagnetic- and the superconducting phase is found to terminate at a tricritical point, where two second-order lines originate. At these lines, the system undergoes a transition to- and from a phase exhibiting both antiferromagnetic order and superconductivity. At finite temperatures above the spin-disordering line, quantum-critical behavior is found. For specific values of the model parameters, it is possible to obtain SO(5) symmetry involving the spin- and the phase-sector at the tricritical point. Although this symmetry is explicitly broken by the projection to the lower Hubbard band, it survives on the mean-field level, and modes related to a spontaneously broken SO(5) symmetry are present on the level of the random phase approximation in the superconducting phase.Comment: 16 pages Revtex, 5 figure
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