Effect of gyro verticality error on lateral autoland tracking performance for an inertially smoothed control law

NASA Technical Reports Server (NTRS)

Thibodeaux, J. J.

1977-01-01

The results of a simulation study performed to determine the effects of gyro verticality error on lateral autoland tracking and landing performance are presented. A first order vertical gyro error model was used to generate the measurement of the roll attitude feedback signal normally supplied by an inertial navigation system. The lateral autoland law used was an inertially smoothed control design. The effect of initial angular gyro tilt errors (2 deg, 3 deg, 4 deg, and 5 deg), introduced prior to localizer capture, were investigated by use of a small perturbation aircraft simulation. These errors represent the deviations which could occur in the conventional attitude sensor as a result of the maneuver-induced spin-axis misalinement and drift. Results showed that for a 1.05 deg per minute erection rate and a 5 deg initial tilt error, ON COURSE autoland control logic was not satisfied. Failure to attain the ON COURSE mode precluded high control loop gains and localizer beam path integration and resulted in unacceptable beam standoff at touchdown.

Spline-Based Smoothing of Airfoil Curvatures

NASA Technical Reports Server (NTRS)

Li, W.; Krist, S.

2008-01-01

Constrained fitting for airfoil curvature smoothing (CFACS) is a splinebased method of interpolating airfoil surface coordinates (and, concomitantly, airfoil thicknesses) between specified discrete design points so as to obtain smoothing of surface-curvature profiles in addition to basic smoothing of surfaces. CFACS was developed in recognition of the fact that the performance of a transonic airfoil is directly related to both the curvature profile and the smoothness of the airfoil surface. Older methods of interpolation of airfoil surfaces involve various compromises between smoothing of surfaces and exact fitting of surfaces to specified discrete design points. While some of the older methods take curvature profiles into account, they nevertheless sometimes yield unfavorable results, including curvature oscillations near end points and substantial deviations from desired leading-edge shapes. In CFACS as in most of the older methods, one seeks a compromise between smoothing and exact fitting. Unlike in the older methods, the airfoil surface is modified as little as possible from its original specified form and, instead, is smoothed in such a way that the curvature profile becomes a smooth fit of the curvature profile of the original airfoil specification. CFACS involves a combination of rigorous mathematical modeling and knowledge-based heuristics. Rigorous mathematical formulation provides assurance of removal of undesirable curvature oscillations with minimum modification of the airfoil geometry. Knowledge-based heuristics bridge the gap between theory and designers best practices. In CFACS, one of the measures of the deviation of an airfoil surface from smoothness is the sum of squares of the jumps in the third derivatives of a cubicspline interpolation of the airfoil data. This measure is incorporated into a formulation for minimizing an overall deviation- from-smoothness measure of the airfoil data within a specified fitting error tolerance. CFACS has been

Smoothing the Marmousi Model

NASA Astrophysics Data System (ADS)

Žáček, K.

Summary- The only way to make an excessively complex velocity model suitable for application of ray-based methods, such as the Gaussian beam or Gaussian packet methods, is to smooth it. We have smoothed the Marmousi model by choosing a coarser grid and by minimizing the second spatial derivatives of the slowness. This was done by minimizing the relevant Sobolev norm of slowness. We show that minimizing the relevant Sobolev norm of slowness is a suitable technique for preparing the optimum models for asymptotic ray theory methods. However, the price we pay for a model suitable for ray tracing is an increase of the difference between the smoothed and original model. Similarly, the estimated error in the travel time also increases due to the difference between the models. In smoothing the Marmousi model, we have found the estimated error of travel times at the verge of acceptability. Due to the low frequencies in the wavefield of the original Marmousi data set, we have found the Gaussian beams and Gaussian packets at the verge of applicability even in models sufficiently smoothed for ray tracing.

The CACAO Method for Smoothing, Gap Filling, and Characterizing Seasonal Anomalies in Satellite Time Series

NASA Technical Reports Server (NTRS)

Verger, Aleixandre; Baret, F.; Weiss, M.; Kandasamy, S.; Vermote, E.

2013-01-01

Consistent, continuous, and long time series of global biophysical variables derived from satellite data are required for global change research. A novel climatology fitting approach called CACAO (Consistent Adjustment of the Climatology to Actual Observations) is proposed to reduce noise and fill gaps in time series by scaling and shifting the seasonal climatological patterns to the actual observations. The shift and scale CACAO parameters adjusted for each season allow quantifying shifts in the timing of seasonal phenology and inter-annual variations in magnitude as compared to the average climatology. CACAO was assessed first over simulated daily Leaf Area Index (LAI) time series with varying fractions of missing data and noise. Then, performances were analyzed over actual satellite LAI products derived from AVHRR Long-Term Data Record for the 1981-2000 period over the BELMANIP2 globally representative sample of sites. Comparison with two widely used temporal filtering methods-the asymmetric Gaussian (AG) model and the Savitzky-Golay (SG) filter as implemented in TIMESAT-revealed that CACAO achieved better performances for smoothing AVHRR time series characterized by high level of noise and frequent missing observations. The resulting smoothed time series captures well the vegetation dynamics and shows no gaps as compared to the 50-60% of still missing data after AG or SG reconstructions. Results of simulation experiments as well as confrontation with actual AVHRR time series indicate that the proposed CACAO method is more robust to noise and missing data than AG and SG methods for phenology extraction.

Direct evidence for a position input to the smooth pursuit system.

PubMed

Blohm, Gunnar; Missal, Marcus; Lefèvre, Philippe

2005-07-01

When objects move in our environment, the orientation of the visual axis in space requires the coordination of two types of eye movements: saccades and smooth pursuit. The principal input to the saccadic system is position error, whereas it is velocity error for the smooth pursuit system. Recently, it has been shown that catch-up saccades to moving targets are triggered and programmed by using velocity error in addition to position error. Here, we show that, when a visual target is flashed during ongoing smooth pursuit, it evokes a smooth eye movement toward the flash. The velocity of this evoked smooth movement is proportional to the position error of the flash; it is neither influenced by the velocity of the ongoing smooth pursuit eye movement nor by the occurrence of a saccade, but the effect is absent if the flash is ignored by the subject. Furthermore, the response started around 85 ms after the flash presentation and decayed with an average time constant of 276 ms. Thus this is the first direct evidence of a position input to the smooth pursuit system. This study shows further evidence for a coupling between saccadic and smooth pursuit systems. It also suggests that there is an interaction between position and velocity error signals in the control of more complex movements.

A study on suppressing transmittance fluctuations for air-gapped Glan-type polarizing prisms

NASA Astrophysics Data System (ADS)

Zhang, Chuanfa; Li, Dailin; Zhu, Huafeng; Li, Chuanzhi; Jiao, Zhiyong; Wang, Ning; Xu, Zhaopeng; Wang, Xiumin; Song, Lianke

2018-05-01

Light intensity transmittance is a key parameter for the design of polarizing prisms, while sometimes its experimental curves based on spatial incident angle presents periodical fluctuations. Here, we propose a novel method for completely suppressing these fluctuations via setting a glued error angle in the air gap of Glan-Taylor prisms. The proposal consists of: an accurate formula of the intensity transmittance for Glan-Taylor prisms, a numerical simulation and a contrast experiment of Glan-Taylor prisms for analyzing the causes of the fluctuations, and a simple method for accurately measuring the glued error angle. The result indicates that when the setting glued error angle is larger than the critical angle for a certain polarizing prism, the fluctuations can be completely suppressed, and a smooth intensity transmittance curve can be obtained. Besides, the critical angle in the air gap for suppressing the fluctuations is decreased with the increase of beam spot size. This method has the advantage of having less demand for the prism position in optical systems.

NUMERICAL CONVERGENCE IN SMOOTHED PARTICLE HYDRODYNAMICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Qirong; Li, Yuexing; Hernquist, Lars

2015-02-10

We study the convergence properties of smoothed particle hydrodynamics (SPH) using numerical tests and simple analytic considerations. Our analysis shows that formal numerical convergence is possible in SPH only in the joint limit N → ∞, h → 0, and N{sub nb} → ∞, where N is the total number of particles, h is the smoothing length, and N{sub nb} is the number of neighbor particles within the smoothing volume used to compute smoothed estimates. Previous work has generally assumed that the conditions N → ∞ and h → 0 are sufficient to achieve convergence, while holding N{sub nb} fixed.more » We demonstrate that if N{sub nb} is held fixed as the resolution is increased, there will be a residual source of error that does not vanish as N → ∞ and h → 0. Formal numerical convergence in SPH is possible only if N{sub nb} is increased systematically as the resolution is improved. Using analytic arguments, we derive an optimal compromise scaling for N{sub nb} by requiring that this source of error balance that present in the smoothing procedure. For typical choices of the smoothing kernel, we find N{sub nb} ∝N {sup 0.5}. This means that if SPH is to be used as a numerically convergent method, the required computational cost does not scale with particle number as O(N), but rather as O(N {sup 1} {sup +} {sup δ}), where δ ≈ 0.5, with a weak dependence on the form of the smoothing kernel.« less

Corner smoothing of 2D milling toolpath using b-spline curve by optimizing the contour error and the feedrate

NASA Astrophysics Data System (ADS)

Özcan, Abdullah; Rivière-Lorphèvre, Edouard; Ducobu, François

2018-05-01

In part manufacturing, efficient process should minimize the cycle time needed to reach the prescribed quality on the part. In order to optimize it, the machining time needs to be as low as possible and the quality needs to meet some requirements. For a 2D milling toolpath defined by sharp corners, the programmed feedrate is different from the reachable feedrate due to kinematic limits of the motor drives. This phenomena leads to a loss of productivity. Smoothing the toolpath allows to reduce significantly the machining time but the dimensional accuracy should not be neglected. Therefore, a way to address the problem of optimizing a toolpath in part manufacturing is to take into account the manufacturing time and the part quality. On one hand, maximizing the feedrate will minimize the manufacturing time and, on the other hand, the maximum of the contour error needs to be set under a threshold to meet the quality requirements. This paper presents a method to optimize sharp corner smoothing using b-spline curves by adjusting the control points defining the curve. The objective function used in the optimization process is based on the contour error and the difference between the programmed feedrate and an estimation of the reachable feedrate. The estimation of the reachable feedrate is based on geometrical information. Some simulation results are presented in the paper and the machining times are compared in each cases.

Effects of errors and gaps in spatial data sets on assessment of conservation progress.

PubMed

Visconti, P; Di Marco, M; Álvarez-Romero, J G; Januchowski-Hartley, S R; Pressey, R L; Weeks, R; Rondinini, C

2013-10-01

Data on the location and extent of protected areas, ecosystems, and species' distributions are essential for determining gaps in biodiversity protection and identifying future conservation priorities. However, these data sets always come with errors in the maps and associated metadata. Errors are often overlooked in conservation studies, despite their potential negative effects on the reported extent of protection of species and ecosystems. We used 3 case studies to illustrate the implications of 3 sources of errors in reporting progress toward conservation objectives: protected areas with unknown boundaries that are replaced by buffered centroids, propagation of multiple errors in spatial data, and incomplete protected-area data sets. As of 2010, the frequency of protected areas with unknown boundaries in the World Database on Protected Areas (WDPA) caused the estimated extent of protection of 37.1% of the terrestrial Neotropical mammals to be overestimated by an average 402.8% and of 62.6% of species to be underestimated by an average 10.9%. Estimated level of protection of the world's coral reefs was 25% higher when using recent finer-resolution data on coral reefs as opposed to globally available coarse-resolution data. Accounting for additional data sets not yet incorporated into WDPA contributed up to 6.7% of additional protection to marine ecosystems in the Philippines. We suggest ways for data providers to reduce the errors in spatial and ancillary data and ways for data users to mitigate the effects of these errors on biodiversity assessments. © 2013 Society for Conservation Biology.

Utility of a novel error-stepping method to improve gradient-based parameter identification by increasing the smoothness of the local objective surface: a case-study of pulmonary mechanics.

PubMed

Docherty, Paul D; Schranz, Christoph; Chase, J Geoffrey; Chiew, Yeong Shiong; Möller, Knut

2014-05-01

Accurate model parameter identification relies on accurate forward model simulations to guide convergence. However, some forward simulation methodologies lack the precision required to properly define the local objective surface and can cause failed parameter identification. The role of objective surface smoothness in identification of a pulmonary mechanics model was assessed using forward simulation from a novel error-stepping method and a proprietary Runge-Kutta method. The objective surfaces were compared via the identified parameter discrepancy generated in a Monte Carlo simulation and the local smoothness of the objective surfaces they generate. The error-stepping method generated significantly smoother error surfaces in each of the cases tested (p<0.0001) and more accurate model parameter estimates than the Runge-Kutta method in three of the four cases tested (p<0.0001) despite a 75% reduction in computational cost. Of note, parameter discrepancy in most cases was limited to a particular oblique plane, indicating a non-intuitive multi-parameter trade-off was occurring. The error-stepping method consistently improved or equalled the outcomes of the Runge-Kutta time-integration method for forward simulations of the pulmonary mechanics model. This study indicates that accurate parameter identification relies on accurate definition of the local objective function, and that parameter trade-off can occur on oblique planes resulting prematurely halted parameter convergence. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Involvement of connexin 43 phosphorylation and gap junctional communication between smooth muscle cells in vasopressin-induced ROCK-dependent vasoconstriction after hemorrhagic shock.

PubMed

Yang, Guangming; Peng, Xiaoyong; Wu, Yue; Li, Tao; Liu, Liangming

2017-10-01

We examined the roles played by gap junctions (GJs) and the GJ channel protein connexin 43 (Cx43) in arginine vasopressin (AVP)-induced vasoconstriction after hemorrhagic shock and their relationship to Rho kinase (ROCK) and protein kinase C (PKC). The results showed that AVP induced an endothelium-independent contraction in rat superior mesenteric arteries (SMAs). Blocking the GJs significantly decreased the contractile response of SMAs and vascular smooth muscle cells (VSMCs) to AVP after shock and hypoxia. The selective Cx43-mimetic peptide inhibited the vascular contractile effect of AVP after shock and hypoxia. AVP restored hypoxia-induced decrease of Cx43 phosphorylation at Ser 262 and gap junctional communication in VSMCs. Activation of RhoA with U-46619 increased the contractile effect of AVP. This effect was antagonized by the ROCK inhibitor Y27632 and the Cx43-mimetic peptide. In contrast, neither an agonist nor an inhibitor of PKC had significant effects on AVP-induced contraction after hemorrhagic shock. In addition, silencing of Cx43 with siRNA blocked the AVP-induced increase of ROCK activity in hypoxic VSMCs. In conclusion, AVP-mediated vascular contractile effects are endothelium and myoendothelial gap junction independent. Gap junctions between VSMCs, gap junctional communication, and Cx43 phosphorylation at Ser 262 play important roles in the vascular effects of AVP. RhoA/ROCK, but not PKC, is involved in this process. Copyright © 2017 the American Physiological Society.

Organometallic chemical vapor deposition and characterization of ZnGeP2/GaP multiple heterostructures on GaP substrates

NASA Technical Reports Server (NTRS)

Xing, G. C.; Bachmann, Klaus J.

1993-01-01

The growth of ZnGeP2/GaP double and multiple heterostructures on GaP substrates by organometallic chemical vapor deposition is reported. These epitaxial films were deposited at a temperature of 580 C using dimethylzinc, trimethylgallium, germane, and phosphine as source gases. With appropriate deposition conditions, mirror smooth epitaxial GaP/ZnGeP2 multiple heterostructures were obtained on (001) GaP substrates. Transmission electron microscopy (TEM) and secondary ion mass spectroscopy (SIMS) studies of the films showed that the interfaces are sharp and smooth. Etching study of the films showed dislocation density on the order of 5x10(exp 4)cm(sup -2). The growth rates of the GaP layers depend linearly on the flow rates of trimethylgallium. While the GaP layers crystallize in zinc-blende structure, the ZnGeP2 layers crystallize in the chalcopyrite structure as determined by (010) electron diffraction pattern. This is the first time that multiple heterostructures combining these two crystal structures were made.

Error analysis for reducing noisy wide-gap concentric cylinder rheometric data for nonlinear fluids - Theory and applications

NASA Technical Reports Server (NTRS)

Borgia, Andrea; Spera, Frank J.

1990-01-01

This work discusses the propagation of errors for the recovery of the shear rate from wide-gap concentric cylinder viscometric measurements of non-Newtonian fluids. A least-square regression of stress on angular velocity data to a system of arbitrary functions is used to propagate the errors for the series solution to the viscometric flow developed by Krieger and Elrod (1953) and Pawlowski (1953) ('power-law' approximation) and for the first term of the series developed by Krieger (1968). A numerical experiment shows that, for measurements affected by significant errors, the first term of the Krieger-Elrod-Pawlowski series ('infinite radius' approximation) and the power-law approximation may recover the shear rate with equal accuracy as the full Krieger-Elrod-Pawlowski solution. An experiment on a clay slurry indicates that the clay has a larger yield stress at rest than during shearing, and that, for the range of shear rates investigated, a four-parameter constitutive equation approximates reasonably well its rheology. The error analysis presented is useful for studying the rheology of fluids such as particle suspensions, slurries, foams, and magma.

A new parametric method to smooth time-series data of metabolites in metabolic networks.

PubMed

Miyawaki, Atsuko; Sriyudthsak, Kansuporn; Hirai, Masami Yokota; Shiraishi, Fumihide

2016-12-01

Mathematical modeling of large-scale metabolic networks usually requires smoothing of metabolite time-series data to account for measurement or biological errors. Accordingly, the accuracy of smoothing curves strongly affects the subsequent estimation of model parameters. Here, an efficient parametric method is proposed for smoothing metabolite time-series data, and its performance is evaluated. To simplify parameter estimation, the method uses S-system-type equations with simple power law-type efflux terms. Iterative calculation using this method was found to readily converge, because parameters are estimated stepwise. Importantly, smoothing curves are determined so that metabolite concentrations satisfy mass balances. Furthermore, the slopes of smoothing curves are useful in estimating parameters, because they are probably close to their true behaviors regardless of errors that may be present in the actual data. Finally, calculations for each differential equation were found to converge in much less than one second if initial parameters are set at appropriate (guessed) values. Copyright © 2016 Elsevier Inc. All rights reserved.

Smooth extrapolation of unknown anatomy via statistical shape models

NASA Astrophysics Data System (ADS)

Grupp, R. B.; Chiang, H.; Otake, Y.; Murphy, R. J.; Gordon, C. R.; Armand, M.; Taylor, R. H.

2015-03-01

Several methods to perform extrapolation of unknown anatomy were evaluated. The primary application is to enhance surgical procedures that may use partial medical images or medical images of incomplete anatomy. Le Fort-based, face-jaw-teeth transplant is one such procedure. From CT data of 36 skulls and 21 mandibles separate Statistical Shape Models of the anatomical surfaces were created. Using the Statistical Shape Models, incomplete surfaces were projected to obtain complete surface estimates. The surface estimates exhibit non-zero error in regions where the true surface is known; it is desirable to keep the true surface and seamlessly merge the estimated unknown surface. Existing extrapolation techniques produce non-smooth transitions from the true surface to the estimated surface, resulting in additional error and a less aesthetically pleasing result. The three extrapolation techniques evaluated were: copying and pasting of the surface estimate (non-smooth baseline), a feathering between the patient surface and surface estimate, and an estimate generated via a Thin Plate Spline trained from displacements between the surface estimate and corresponding vertices of the known patient surface. Feathering and Thin Plate Spline approaches both yielded smooth transitions. However, feathering corrupted known vertex values. Leave-one-out analyses were conducted, with 5% to 50% of known anatomy removed from the left-out patient and estimated via the proposed approaches. The Thin Plate Spline approach yielded smaller errors than the other two approaches, with an average vertex error improvement of 1.46 mm and 1.38 mm for the skull and mandible respectively, over the baseline approach.

Involvement of gap junctions between smooth muscle cells in sustained hypoxic pulmonary vasoconstriction development: a potential role for 15-HETE and 20-HETE.

PubMed

Kizub, Igor V; Lakhkar, Anand; Dhagia, Vidhi; Joshi, Sachindra R; Jiang, Houli; Wolin, Michael S; Falck, John R; Koduru, Sreenivasulu Reddy; Errabelli, Ramu; Jacobs, Elizabeth R; Schwartzman, Michal L; Gupte, Sachin A

2016-04-15

In response to hypoxia, the pulmonary artery normally constricts to maintain optimal ventilation-perfusion matching in the lung, but chronic hypoxia leads to the development of pulmonary hypertension. The mechanisms of sustained hypoxic pulmonary vasoconstriction (HPV) remain unclear. The aim of this study was to determine the role of gap junctions (GJs) between smooth muscle cells (SMCs) in the sustained HPV development and involvement of arachidonic acid (AA) metabolites in GJ-mediated signaling. Vascular tone was measured in bovine intrapulmonary arteries (BIPAs) using isometric force measurement technique. Expression of contractile proteins was determined by Western blot. AA metabolites in the bath fluid were analyzed by mass spectrometry. Prolonged hypoxia elicited endothelium-independent sustained HPV in BIPAs. Inhibition of GJs by 18β-glycyrrhetinic acid (18β-GA) and heptanol, nonspecific blockers, and Gap-27, a specific blocker, decreased HPV in deendothelized BIPAs. The sustained HPV was not dependent on Ca(2+) entry but decreased by removal of Ca(2+) and by Rho-kinase inhibition with Y-27632. Furthermore, inhibition of GJs decreased smooth muscle myosin heavy chain (SM-MHC) expression and myosin light chain phosphorylation in BIPAs. Interestingly, inhibition of 15- and 20-hydroxyeicosatetraenoic acid (HETE) synthesis decreased HPV in deendothelized BIPAs. 15-HETE- and 20-HETE-stimulated constriction of BIPAs was inhibited by 18β-GA and Gap-27. Application of 15-HETE and 20-HETE to BIPAs increased SM-MHC expression, which was also suppressed by 18β-GA and by inhibitors of lipoxygenase and cytochrome P450 monooxygenases. More interestingly, 15,20-dihydroxyeicosatetraenoic acid and 20-OH-prostaglandin E2, novel derivatives of 20-HETE, were detected in tissue bath fluid and synthesis of these derivatives was almost completely abolished by 18β-GA. Taken together, our novel findings show that GJs between SMCs are involved in the sustained HPV in BIPAs, and

Efficiently characterizing the total error in quantum circuits

NASA Astrophysics Data System (ADS)

Carignan-Dugas, Arnaud; Wallman, Joel J.; Emerson, Joseph

A promising technological advancement meant to enlarge our computational means is the quantum computer. Such a device would harvest the quantum complexity of the physical world in order to unfold concrete mathematical problems more efficiently. However, the errors emerging from the implementation of quantum operations are likewise quantum, and hence share a similar level of intricacy. Fortunately, randomized benchmarking protocols provide an efficient way to characterize the operational noise within quantum devices. The resulting figures of merit, like the fidelity and the unitarity, are typically attached to a set of circuit components. While important, this doesn't fulfill the main goal: determining if the error rate of the total circuit is small enough in order to trust its outcome. In this work, we fill the gap by providing an optimal bound on the total fidelity of a circuit in terms of component-wise figures of merit. Our bound smoothly interpolates between the classical regime, in which the error rate grows linearly in the circuit's length, and the quantum regime, which can naturally allow quadratic growth. Conversely, our analysis substantially improves the bounds on single circuit element fidelities obtained through techniques such as interleaved randomized benchmarking. This research was supported by the U.S. Army Research Office through Grant W911NF- 14-1-0103, CIFAR, the Government of Ontario, and the Government of Canada through NSERC and Industry Canada.

Adaptation of catch-up saccades during the initiation of smooth pursuit eye movements.

PubMed

Schütz, Alexander C; Souto, David

2011-04-01

Reduction of retinal speed and alignment of the line of sight are believed to be the respective primary functions of smooth pursuit and saccadic eye movements. As the eye muscles strength can change in the short-term, continuous adjustments of motor signals are required to achieve constant accuracy. While adaptation of saccade amplitude to systematic position errors has been extensively studied, we know less about the adaptive response to position errors during smooth pursuit initiation, when target motion has to be taken into account to program saccades, and when position errors at the saccade endpoint could also be corrected by increasing pursuit velocity. To study short-term adaptation (250 adaptation trials) of tracking eye movements, we introduced a position error during the first catch-up saccade made during the initiation of smooth pursuit-in a ramp-step-ramp paradigm. The target position was either shifted in the direction of the horizontally moving target (forward step), against it (backward step) or orthogonally to it (vertical step). Results indicate adaptation of catch-up saccade amplitude to back and forward steps. With vertical steps, saccades became oblique, by an inflexion of the early or late saccade trajectory. With a similar time course, post-saccadic pursuit velocity was increased in the step direction, adding further evidence that under some conditions pursuit and saccades can act synergistically to reduce position errors.

Investigation of smoothness-increasing accuracy-conserving filters for improving streamline integration through discontinuous fields.

PubMed

Steffen, Michael; Curtis, Sean; Kirby, Robert M; Ryan, Jennifer K

2008-01-01

Streamline integration of fields produced by computational fluid mechanics simulations is a commonly used tool for the investigation and analysis of fluid flow phenomena. Integration is often accomplished through the application of ordinary differential equation (ODE) integrators--integrators whose error characteristics are predicated on the smoothness of the field through which the streamline is being integrated--smoothness which is not available at the inter-element level of finite volume and finite element data. Adaptive error control techniques are often used to ameliorate the challenge posed by inter-element discontinuities. As the root of the difficulties is the discontinuous nature of the data, we present a complementary approach of applying smoothness-enhancing accuracy-conserving filters to the data prior to streamline integration. We investigate whether such an approach applied to uniform quadrilateral discontinuous Galerkin (high-order finite volume) data can be used to augment current adaptive error control approaches. We discuss and demonstrate through numerical example the computational trade-offs exhibited when one applies such a strategy.

Disclosure of Medical Errors in Oman

PubMed Central

Norrish, Mark I. K.

2015-01-01

Objectives: This study aimed to provide insight into the preferences for and perceptions of medical error disclosure (MED) by members of the public in Oman. Methods: Between January and June 2012, an online survey was used to collect responses from 205 members of the public across five governorates of Oman. Results: A disclosure gap was revealed between the respondents’ preferences for MED and perceived current MED practices in Oman. This disclosure gap extended to both the type of error and the person most likely to disclose the error. Errors resulting in patient harm were found to have a strong influence on individuals’ perceived quality of care. In addition, full disclosure was found to be highly valued by respondents and able to mitigate for a perceived lack of care in cases where medical errors led to damages. Conclusion: The perceived disclosure gap between respondents’ MED preferences and perceptions of current MED practices in Oman needs to be addressed in order to increase public confidence in the national health care system. PMID:26052463

Second-order numerical methods for multi-term fractional differential equations: Smooth and non-smooth solutions

NASA Astrophysics Data System (ADS)

Zeng, Fanhai; Zhang, Zhongqiang; Karniadakis, George Em

2017-12-01

Starting with the asymptotic expansion of the error equation of the shifted Gr\\"{u}nwald--Letnikov formula, we derive a new modified weighted shifted Gr\\"{u}nwald--Letnikov (WSGL) formula by introducing appropriate correction terms. We then apply one special case of the modified WSGL formula to solve multi-term fractional ordinary and partial differential equations, and we prove the linear stability and second-order convergence for both smooth and non-smooth solutions. We show theoretically and numerically that numerical solutions up to certain accuracy can be obtained with only a few correction terms. Moreover, the correction terms can be tuned according to the fractional derivative orders without explicitly knowing the analytical solutions. Numerical simulations verify the theoretical results and demonstrate that the new formula leads to better performance compared to other known numerical approximations with similar resolution.

Stress Recovery and Error Estimation for Shell Structures

NASA Technical Reports Server (NTRS)

Yazdani, A. A.; Riggs, H. R.; Tessler, A.

2000-01-01

The Penalized Discrete Least-Squares (PDLS) stress recovery (smoothing) technique developed for two dimensional linear elliptic problems is adapted here to three-dimensional shell structures. The surfaces are restricted to those which have a 2-D parametric representation, or which can be built-up of such surfaces. The proposed strategy involves mapping the finite element results to the 2-D parametric space which describes the geometry, and smoothing is carried out in the parametric space using the PDLS-based Smoothing Element Analysis (SEA). Numerical results for two well-known shell problems are presented to illustrate the performance of SEA/PDLS for these problems. The recovered stresses are used in the Zienkiewicz-Zhu a posteriori error estimator. The estimated errors are used to demonstrate the performance of SEA-recovered stresses in automated adaptive mesh refinement of shell structures. The numerical results are encouraging. Further testing involving more complex, practical structures is necessary.

Combined fabrication process for high-precision aspheric surface based on smoothing polishing and magnetorheological finishing

NASA Astrophysics Data System (ADS)

Nie, Xuqing; Li, Shengyi; Song, Ci; Hu, Hao

2014-08-01

Due to the different curvature everywhere, the aspheric surface is hard to achieve high-precision accuracy by the traditional polishing process. Controlling of the mid-spatial frequency errors (MSFR), in particular, is almost unapproachable. In this paper, the combined fabrication process based on the smoothing polishing (SP) and magnetorheological finishing (MRF) is proposed. The pressure distribution of the rigid polishing lap and semi-flexible polishing lap is calculated. The shape preserving capacity and smoothing effect are compared. The feasibility of smoothing aspheric surface with the semi-flexible polishing lap is verified, and the key technologies in the SP process are discussed. Then, A K4 parabolic surface with the diameter of 500mm is fabricated based on the combined fabrication process. A Φ150 mm semi-flexible lap is used in the SP process to control the MSFR, and the deterministic MRF process is applied to figure the surface error. The root mean square (RMS) error of the aspheric surface converges from 0.083λ (λ=632.8 nm) to 0.008λ. The power spectral density (PSD) result shows that the MSFR are well restrained while the surface error has a great convergence.

Arima model and exponential smoothing method: A comparison

NASA Astrophysics Data System (ADS)

Wan Ahmad, Wan Kamarul Ariffin; Ahmad, Sabri

2013-04-01

This study shows the comparison between Autoregressive Moving Average (ARIMA) model and Exponential Smoothing Method in making a prediction. The comparison is focused on the ability of both methods in making the forecasts with the different number of data sources and the different length of forecasting period. For this purpose, the data from The Price of Crude Palm Oil (RM/tonne), Exchange Rates of Ringgit Malaysia (RM) in comparison to Great Britain Pound (GBP) and also The Price of SMR 20 Rubber Type (cents/kg) with three different time series are used in the comparison process. Then, forecasting accuracy of each model is measured by examinethe prediction error that producedby using Mean Squared Error (MSE), Mean Absolute Percentage Error (MAPE), and Mean Absolute deviation (MAD). The study shows that the ARIMA model can produce a better prediction for the long-term forecasting with limited data sources, butcannot produce a better prediction for time series with a narrow range of one point to another as in the time series for Exchange Rates. On the contrary, Exponential Smoothing Method can produce a better forecasting for Exchange Rates that has a narrow range of one point to another for its time series, while itcannot produce a better prediction for a longer forecasting period.

Mapping GRACE Accelerometer Error

NASA Astrophysics Data System (ADS)

Sakumura, C.; Harvey, N.; McCullough, C. M.; Bandikova, T.; Kruizinga, G. L. H.

2017-12-01

After more than fifteen years in orbit, instrument noise, and accelerometer noise in particular, remains one of the limiting error sources for the NASA/DLR Gravity Recovery and Climate Experiment mission. The recent V03 Level-1 reprocessing campaign used a Kalman filter approach to produce a high fidelity, smooth attitude solution fusing star camera and angular acceleration data. This process provided an unprecedented method for analysis and error estimation of each instrument. The accelerometer exhibited signal aliasing, differential scale factors between electrode plates, and magnetic effects. By applying the noise model developed for the angular acceleration data to the linear measurements, we explore the magnitude and geophysical pattern of gravity field error due to the electrostatic accelerometer.

Prediction of discretization error using the error transport equation

NASA Astrophysics Data System (ADS)

Celik, Ismail B.; Parsons, Don Roscoe

2017-06-01

This study focuses on an approach to quantify the discretization error associated with numerical solutions of partial differential equations by solving an error transport equation (ETE). The goal is to develop a method that can be used to adequately predict the discretization error using the numerical solution on only one grid/mesh. The primary problem associated with solving the ETE is the formulation of the error source term which is required for accurately predicting the transport of the error. In this study, a novel approach is considered which involves fitting the numerical solution with a series of locally smooth curves and then blending them together with a weighted spline approach. The result is a continuously differentiable analytic expression that can be used to determine the error source term. Once the source term has been developed, the ETE can easily be solved using the same solver that is used to obtain the original numerical solution. The new methodology is applied to the two-dimensional Navier-Stokes equations in the laminar flow regime. A simple unsteady flow case is also considered. The discretization error predictions based on the methodology presented in this study are in good agreement with the 'true error'. While in most cases the error predictions are not quite as accurate as those from Richardson extrapolation, the results are reasonable and only require one numerical grid. The current results indicate that there is much promise going forward with the newly developed error source term evaluation technique and the ETE.

Smoothing spline ANOVA frailty model for recurrent event data.

PubMed

Du, Pang; Jiang, Yihua; Wang, Yuedong

2011-12-01

Gap time hazard estimation is of particular interest in recurrent event data. This article proposes a fully nonparametric approach for estimating the gap time hazard. Smoothing spline analysis of variance (ANOVA) decompositions are used to model the log gap time hazard as a joint function of gap time and covariates, and general frailty is introduced to account for between-subject heterogeneity and within-subject correlation. We estimate the nonparametric gap time hazard function and parameters in the frailty distribution using a combination of the Newton-Raphson procedure, the stochastic approximation algorithm (SAA), and the Markov chain Monte Carlo (MCMC) method. The convergence of the algorithm is guaranteed by decreasing the step size of parameter update and/or increasing the MCMC sample size along iterations. Model selection procedure is also developed to identify negligible components in a functional ANOVA decomposition of the log gap time hazard. We evaluate the proposed methods with simulation studies and illustrate its use through the analysis of bladder tumor data. © 2011, The International Biometric Society.

Gap filling strategies and error in estimating annual soil respiration

USDA-ARS?s Scientific Manuscript database

Soil respiration (Rsoil) is one of the largest CO2 fluxes in the global carbon (C) cycle. Estimation of annual Rsoil requires extrapolation of survey measurements or gap-filling of automated records to produce a complete time series. While many gap-filling methodologies have been employed, there is ...

Compensating for estimation smoothing in kriging

USGS Publications Warehouse

Olea, R.A.; Pawlowsky, Vera

1996-01-01

Smoothing is a characteristic inherent to all minimum mean-square-error spatial estimators such as kriging. Cross-validation can be used to detect and model such smoothing. Inversion of the model produces a new estimator-compensated kriging. A numerical comparison based on an exhaustive permeability sampling of a 4-fr2 slab of Berea Sandstone shows that the estimation surface generated by compensated kriging has properties intermediate between those generated by ordinary kriging and stochastic realizations resulting from simulated annealing and sequential Gaussian simulation. The frequency distribution is well reproduced by the compensated kriging surface, which also approximates the experimental semivariogram well - better than ordinary kriging, but not as well as stochastic realizations. Compensated kriging produces surfaces that are more accurate than stochastic realizations, but not as accurate as ordinary kriging. ?? 1996 International Association for Mathematical Geology.

Proximal-distal differences in movement smoothness reflect differences in biomechanics.

PubMed

Salmond, Layne H; Davidson, Andrew D; Charles, Steven K

2017-03-01

Smoothness is a hallmark of healthy movement. Past research indicates that smoothness may be a side product of a control strategy that minimizes error. However, this is not the only reason for smooth movements. Our musculoskeletal system itself contributes to movement smoothness: the mechanical impedance (inertia, damping, and stiffness) of our limbs and joints resists sudden change, resulting in a natural smoothing effect. How the biomechanics and neural control interact to result in an observed level of smoothness is not clear. The purpose of this study is to 1 ) characterize the smoothness of wrist rotations, 2 ) compare it with the smoothness of planar shoulder-elbow (reaching) movements, and 3 ) determine the cause of observed differences in smoothness. Ten healthy subjects performed wrist and reaching movements involving different targets, directions, and speeds. We found wrist movements to be significantly less smooth than reaching movements and to vary in smoothness with movement direction. To identify the causes underlying these observations, we tested a number of hypotheses involving differences in bandwidth, signal-dependent noise, speed, impedance anisotropy, and movement duration. Our simulations revealed that proximal-distal differences in smoothness reflect proximal-distal differences in biomechanics: the greater impedance of the shoulder-elbow filters neural noise more than the wrist. In contrast, differences in signal-dependent noise and speed were not sufficiently large to recreate the observed differences in smoothness. We also found that the variation in wrist movement smoothness with direction appear to be caused by, or at least correlated with, differences in movement duration, not impedance anisotropy. NEW & NOTEWORTHY This article presents the first thorough characterization of the smoothness of wrist rotations (flexion-extension and radial-ulnar deviation) and comparison with the smoothness of reaching (shoulder-elbow) movements. We found

Nonequilibrium flows with smooth particle applied mechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kum, Oyeon

1995-07-01

Smooth particle methods are relatively new methods for simulating solid and fluid flows through they have a 20-year history of solving complex hydrodynamic problems in astrophysics, such as colliding planets and stars, for which correct answers are unknown. The results presented in this thesis evaluate the adaptability or fitness of the method for typical hydrocode production problems. For finite hydrodynamic systems, boundary conditions are important. A reflective boundary condition with image particles is a good way to prevent a density anomaly at the boundary and to keep the fluxes continuous there. Boundary values of temperature and velocity can be separatelymore » controlled. The gradient algorithm, based on differentiating the smooth particle expression for (uρ) and (Tρ), does not show numerical instabilities for the stress tensor and heat flux vector quantities which require second derivatives in space when Fourier`s heat-flow law and Newton`s viscous force law are used. Smooth particle methods show an interesting parallel linking to them to molecular dynamics. For the inviscid Euler equation, with an isentropic ideal gas equation of state, the smooth particle algorithm generates trajectories isomorphic to those generated by molecular dynamics. The shear moduli were evaluated based on molecular dynamics calculations for the three weighting functions, B spline, Lucy, and Cusp functions. The accuracy and applicability of the methods were estimated by comparing a set of smooth particle Rayleigh-Benard problems, all in the laminar regime, to corresponding highly-accurate grid-based numerical solutions of continuum equations. Both transient and stationary smooth particle solutions reproduce the grid-based data with velocity errors on the order of 5%. The smooth particle method still provides robust solutions at high Rayleigh number where grid-based methods fails.« less

A User Guide for Smoothing Air Traffic Radar Data

NASA Technical Reports Server (NTRS)

Bach, Ralph E.; Paielli, Russell A.

2014-01-01

Matlab software was written to provide smoothing of radar tracking data to simulate ADS-B (Automatic Dependent Surveillance-Broadcast) data in order to test a tactical conflict probe. The probe, called TSAFE (Tactical Separation-Assured Flight Environment), is designed to handle air-traffic conflicts left undetected or unresolved when loss-of-separation is predicted to occur within approximately two minutes. The data stream that is down-linked from an aircraft equipped with an ADS-B system would include accurate GPS-derived position and velocity information at sample rates of 1 Hz. Nation-wide ADS-B equipage (mandated by 2020) should improve surveillance accuracy and TSAFE performance. Currently, position data are provided by Center radar (nominal 12-sec samples) and Terminal radar (nominal 4.8-sec samples). Aircraft ground speed and ground track are estimated using real-time filtering, causing lags up to 60 sec, compromising performance of a tactical resolution tool. Offline smoothing of radar data reduces wild-point errors, provides a sample rate as high as 1 Hz, and yields more accurate and lag-free estimates of ground speed, ground track, and climb rate. Until full ADS-B implementation is available, smoothed radar data should provide reasonable track estimates for testing TSAFE in an ADS-B-like environment. An example illustrates the smoothing of radar data and shows a comparison of smoothed-radar and ADS-B tracking. This document is intended to serve as a guide for using the smoothing software.

Effects of Piecewise Spatial Smoothing in 4-D SPECT Reconstruction

NASA Astrophysics Data System (ADS)

Qi, Wenyuan; Yang, Yongyi; King, Michael A.

2014-02-01

further reduce the error level in the myocardium in 4-D reconstruction along with motion-compensated temporal smoothing. In contrast to quadratic spatial smoothing, TV smoothing could reduce the noise level in the LV at a faster pace than the increase in the bias level, thereby achieving a net decrease in the error level. In particular, at the same noise level, TV smoothing could reduce the bias by about 30% compared to quadratic smoothing. Moreover, the CHO results indicate that TV could also improve the lesion detectability even when the lesion is small. The PAC results show that, at the same noise level, TV smoothing achieved lower temporal bias, which is also consistent with the improved spatial resolution of the LV in reconstruction. The improvement in blurring effects by TV was also observed in the clinical images.

Using Cochran's Z Statistic to Test the Kernel-Smoothed Item Response Function Differences between Focal and Reference Groups

ERIC Educational Resources Information Center

Zheng, Yinggan; Gierl, Mark J.; Cui, Ying

2010-01-01

This study combined the kernel smoothing procedure and a nonparametric differential item functioning statistic--Cochran's Z--to statistically test the difference between the kernel-smoothed item response functions for reference and focal groups. Simulation studies were conducted to investigate the Type I error and power of the proposed…

Verification of micro-scale photogrammetry for smooth three-dimensional object measurement

NASA Astrophysics Data System (ADS)

Sims-Waterhouse, Danny; Piano, Samanta; Leach, Richard

2017-05-01

By using sub-millimetre laser speckle pattern projection we show that photogrammetry systems are able to measure smooth three-dimensional objects with surface height deviations less than 1 μm. The projection of laser speckle patterns allows correspondences on the surface of smooth spheres to be found, and as a result, verification artefacts with low surface height deviations were measured. A combination of VDI/VDE and ISO standards were also utilised to provide a complete verification method, and determine the quality parameters for the system under test. Using the proposed method applied to a photogrammetry system, a 5 mm radius sphere was measured with an expanded uncertainty of 8.5 μm for sizing errors, and 16.6 μm for form errors with a 95 % confidence interval. Sphere spacing lengths between 6 mm and 10 mm were also measured by the photogrammetry system, and were found to have expanded uncertainties of around 20 μm with a 95 % confidence interval.

Movement trajectory smoothness is not associated with the endpoint accuracy of rapid multi-joint arm movements in young and older adults

PubMed Central

Poston, Brach; Van Gemmert, Arend W.A.; Sharma, Siddharth; Chakrabarti, Somesh; Zavaremi, Shahrzad H.; Stelmach, George

2013-01-01

The minimum variance theory proposes that motor commands are corrupted by signal-dependent noise and smooth trajectories with low noise levels are selected to minimize endpoint error and endpoint variability. The purpose of the study was to determine the contribution of trajectory smoothness to the endpoint accuracy and endpoint variability of rapid multi-joint arm movements. Young and older adults performed arm movements (4 blocks of 25 trials) as fast and as accurately as possible to a target with the right (dominant) arm. Endpoint accuracy and endpoint variability along with trajectory smoothness and error were quantified for each block of trials. Endpoint error and endpoint variance were greater in older adults compared with young adults, but decreased at a similar rate with practice for the two age groups. The greater endpoint error and endpoint variance exhibited by older adults were primarily due to impairments in movement extent control and not movement direction control. The normalized jerk was similar for the two age groups, but was not strongly associated with endpoint error or endpoint variance for either group. However, endpoint variance was strongly associated with endpoint error for both the young and older adults. Finally, trajectory error was similar for both groups and was weakly associated with endpoint error for the older adults. The findings are not consistent with the predictions of the minimum variance theory, but support and extend previous observations that movement trajectories and endpoints are planned independently. PMID:23584101

Experimental determination of the navigation error of the 4-D navigation, guidance, and control systems on the NASA B-737 airplane

NASA Technical Reports Server (NTRS)

Knox, C. E.

1978-01-01

Navigation error data from these flights are presented in a format utilizing three independent axes - horizontal, vertical, and time. The navigation position estimate error term and the autopilot flight technical error term are combined to form the total navigation error in each axis. This method of error presentation allows comparisons to be made between other 2-, 3-, or 4-D navigation systems and allows experimental or theoretical determination of the navigation error terms. Position estimate error data are presented with the navigation system position estimate based on dual DME radio updates that are smoothed with inertial velocities, dual DME radio updates that are smoothed with true airspeed and magnetic heading, and inertial velocity updates only. The normal mode of navigation with dual DME updates that are smoothed with inertial velocities resulted in a mean error of 390 m with a standard deviation of 150 m in the horizontal axis; a mean error of 1.5 m low with a standard deviation of less than 11 m in the vertical axis; and a mean error as low as 252 m with a standard deviation of 123 m in the time axis.

Stress Recovery and Error Estimation for 3-D Shell Structures

NASA Technical Reports Server (NTRS)

Riggs, H. R.

2000-01-01

The C1-continuous stress fields obtained from finite element analyses are in general lower- order accurate than are the corresponding displacement fields. Much effort has focussed on increasing their accuracy and/or their continuity, both for improved stress prediction and especially error estimation. A previous project developed a penalized, discrete least squares variational procedure that increases the accuracy and continuity of the stress field. The variational problem is solved by a post-processing, 'finite-element-type' analysis to recover a smooth, more accurate, C1-continuous stress field given the 'raw' finite element stresses. This analysis has been named the SEA/PDLS. The recovered stress field can be used in a posteriori error estimators, such as the Zienkiewicz-Zhu error estimator or equilibrium error estimators. The procedure was well-developed for the two-dimensional (plane) case involving low-order finite elements. It has been demonstrated that, if optimal finite element stresses are used for the post-processing, the recovered stress field is globally superconvergent. Extension of this work to three dimensional solids is straightforward. Attachment: Stress recovery and error estimation for shell structure (abstract only). A 4-node, shear-deformable flat shell element developed via explicit Kirchhoff constraints (abstract only). A novel four-node quadrilateral smoothing element for stress enhancement and error estimation (abstract only).

Smooth Approximation l 0-Norm Constrained Affine Projection Algorithm and Its Applications in Sparse Channel Estimation

PubMed Central

2014-01-01

We propose a smooth approximation l 0-norm constrained affine projection algorithm (SL0-APA) to improve the convergence speed and the steady-state error of affine projection algorithm (APA) for sparse channel estimation. The proposed algorithm ensures improved performance in terms of the convergence speed and the steady-state error via the combination of a smooth approximation l 0-norm (SL0) penalty on the coefficients into the standard APA cost function, which gives rise to a zero attractor that promotes the sparsity of the channel taps in the channel estimation and hence accelerates the convergence speed and reduces the steady-state error when the channel is sparse. The simulation results demonstrate that our proposed SL0-APA is superior to the standard APA and its sparsity-aware algorithms in terms of both the convergence speed and the steady-state behavior in a designated sparse channel. Furthermore, SL0-APA is shown to have smaller steady-state error than the previously proposed sparsity-aware algorithms when the number of nonzero taps in the sparse channel increases. PMID:24790588

Wisps in the outer edge of the Keeler Gap

NASA Astrophysics Data System (ADS)

Tiscareno, Matthew S.; Arnault, Ethan G.

2015-11-01

Superposed upon the relatively smooth outer edge of the Keeler Gap are a system of "wisps," which appear to be ring material protruding inward into the gap, usually with a sharp trailing edge and a smooth gradation back to the background edge location on the leading side (Porco et al. 2005, Science). The radial amplitude of wisps is usually 0.5 to 1 km, and their azimuthal extent is approximately a degree of longitude (~2400 km). Wisps are likely caused by an interplay between Daphnis (and perhaps other moons) and embedded moonlets within the ring, though the details remain unclear.Aside from the wisps, the Keeler Gap outer edge is the only one of the five sharp edges in the outer part of Saturn's A ring that is reasonably smooth in appearance (Tiscareno et al. 2005, DPS), with occultations indicating residuals less than 1 km upon a possibly non-zero eccentricity (R.G. French, personal communication, 2014). The other four (the inner and outer edges of the Encke Gap, the inner edge of the Keeler Gap, and the outer edge of the A ring itself) are characterized by wavy structure at moderate to high spatial frequencies, with amplitudes ranging from 2 to 30 km (Tiscareno et al. 2005, DPS).We will present a catalogue of wisp detections in Cassini images. We carry out repeated gaussian fits of the radial edge location in order to characterize edge structure and visually scan those fitted edges in order to detect wisps. With extensive coverage in longitude and in time, we will report on how wisps evolve and move, both within an orbit period and on longer timescales. We will also report on the frequency and interpretation of wisps that deviate from the standard morphology. We will discuss the implications of our results for the origin and nature of wisps, and for the larger picture of how masses interact within Saturn's rings.

Wisps in the outer edge of the Keeler Gap

NASA Astrophysics Data System (ADS)

Tiscareno, M. S.; Arnault, E. G.

2014-12-01

The outer part of Saturn's A ring contains five sharp edges: the inner and outer edges of the Encke Gap and of the Keeler Gap (which contain the moons Pan and Daphnis, respectively), and the outer edge of the A ring itself. Four of these five edges are characterized by structure at moderate to high spatial frequencies, with amplitudes ranging from 2 to 30 km (Tiscareno et al. 2005, DPS). Only the outer edge of the Keeler Gap is reasonably smooth in appearance (Tiscareno et al. 2005, DPS), with occultations indicating residuals less than 1 km upon a possibly non-zero eccentricity (R.G. French, personal communication, 2014). Superposed upon the relatively smooth outer edge of the Keeler Gap are a system of "wisps," which appear to be ring material protruding inward into the gap, usually with a sharp trailing edge and a smooth gradation back to the background edge location on the leading side (Porco et al. 2005, Science). The radial amplitude of wisps is usually 0.5 to 1 km, and their azimuthal extent is approximately a degree of longitude (~2400 km). Wisps are likely caused by an interplay between Daphnis (and perhaps other moons) and embedded moonlets within the ring, though the details remain unclear. We will present a catalogue of wisp detections in Cassini images. We carry out repeated gaussian fits of the radial edge location in order to characterize edge structure (see Figure, which compares our fitted edge to the figure presented by Porco et al. 2005) and visually scan those fitted edges in order to detect wisps. With extensive coverage in longitude and in time, we will report on how wisps evolve and move, both within an orbit period and on longer timescales. We will also report on the frequency and interpretation of wisps that deviate from the standard morphology. We will discuss the implications of our results for the origin and nature of wisps, and for the larger picture of how masses interact within Saturn's rings.

Implication of adaptive smoothness constraint and Helmert variance component estimation in seismic slip inversion

NASA Astrophysics Data System (ADS)

Fan, Qingbiao; Xu, Caijun; Yi, Lei; Liu, Yang; Wen, Yangmao; Yin, Zhi

2017-10-01

When ill-posed problems are inverted, the regularization process is equivalent to adding constraint equations or prior information from a Bayesian perspective. The veracity of the constraints (or the regularization matrix R) significantly affects the solution, and a smoothness constraint is usually added in seismic slip inversions. In this paper, an adaptive smoothness constraint (ASC) based on the classic Laplacian smoothness constraint (LSC) is proposed. The ASC not only improves the smoothness constraint, but also helps constrain the slip direction. A series of experiments are conducted in which different magnitudes of noise are imposed and different densities of observation are assumed, and the results indicated that the ASC was superior to the LSC. Using the proposed ASC, the Helmert variance component estimation method is highlighted as the best for selecting the regularization parameter compared with other methods, such as generalized cross-validation or the mean squared error criterion method. The ASC may also benefit other ill-posed problems in which a smoothness constraint is required.

Recognizing and managing errors of cognitive underspecification.

PubMed

Duthie, Elizabeth A

2014-03-01

James Reason describes cognitive underspecification as incomplete communication that creates a knowledge gap. Errors occur when an information mismatch occurs in bridging that gap with a resulting lack of shared mental models during the communication process. There is a paucity of studies in health care examining this cognitive error and the role it plays in patient harm. The goal of the following case analyses is to facilitate accurate recognition, identify how it contributes to patient harm, and suggest appropriate management strategies. Reason's human error theory is applied in case analyses of errors of cognitive underspecification. Sidney Dekker's theory of human incident investigation is applied to event investigation to facilitate identification of this little recognized error. Contributory factors leading to errors of cognitive underspecification include workload demands, interruptions, inexperienced practitioners, and lack of a shared mental model. Detecting errors of cognitive underspecification relies on blame-free listening and timely incident investigation. Strategies for interception include two-way interactive communication, standardization of communication processes, and technological support to ensure timely access to documented clinical information. Although errors of cognitive underspecification arise at the sharp end with the care provider, effective management is dependent upon system redesign that mitigates the latent contributory factors. Cognitive underspecification is ubiquitous whenever communication occurs. Accurate identification is essential if effective system redesign is to occur.

Human Motion Perception and Smooth Eye Movements Show Similar Directional Biases for Elongated Apertures

NASA Technical Reports Server (NTRS)

Beutter, Brent R.; Stone, Leland S.

1997-01-01

Although numerous studies have examined the relationship between smooth-pursuit eye movements and motion perception, it remains unresolved whether a common motion-processing system subserves both perception and pursuit. To address this question, we simultaneously recorded perceptual direction judgments and the concomitant smooth eye movement response to a plaid stimulus that we have previously shown generates systematic perceptual errors. We measured the perceptual direction biases psychophysically and the smooth eye-movement direction biases using two methods (standard averaging and oculometric analysis). We found that the perceptual and oculomotor biases were nearly identical suggesting that pursuit and perception share a critical motion processing stage, perhaps in area MT or MST of extrastriate visual cortex.

Human motion perception and smooth eye movements show similar directional biases for elongated apertures

NASA Technical Reports Server (NTRS)

Beutter, B. R.; Stone, L. S.

1998-01-01

Although numerous studies have examined the relationship between smooth-pursuit eye movements and motion perception, it remains unresolved whether a common motion-processing system subserves both perception and pursuit. To address this question, we simultaneously recorded perceptual direction judgments and the concomitant smooth eye-movement response to a plaid stimulus that we have previously shown generates systematic perceptual errors. We measured the perceptual direction biases psychophysically and the smooth eye-movement direction biases using two methods (standard averaging and oculometric analysis). We found that the perceptual and oculomotor biases were nearly identical, suggesting that pursuit and perception share a critical motion processing stage, perhaps in area MT or MST of extrastriate visual cortex.

Ultra-Smooth ZnS Films Grown on Silicon via Pulsed Laser Deposition

NASA Astrophysics Data System (ADS)

Reidy, Christopher; Tate, Janet

2011-10-01

Ultra-smooth, high quality ZnS films were grown on (100) and (111) oriented Si wafers via pulsed laser deposition with a KrF excimer laser in UHV (10-9 Torr). The resultant films were examined with optical spectroscopy, electron diffraction, and electron probe microanalysis. The films have an rms roughness of ˜1.5 nm, and the film stoichiometry is approximately Zn:S :: 1:0.87. Additionally, each film exhibits an optical interference pattern which is not a function of probing location on the sample, indicating excellent film thickness uniformity. Motivation for high-quality ZnS films comes from a proposed experiment to measure carrier amplification via impact ionization at the boundary between a wide-gap and a narrow-gap semiconductor. If excited charge carriers in a sufficiently wide-gap harvester can be extracted into a narrow-gap host material, impact ionization may occur. We seek near-perfect interfaces between ZnS, with a direct gap between 3.3 and 3.7 eV, and Si, with an indirect gap of 1.1 eV.

Foot Structure in Japanese Speech Errors: Normal vs. Pathological

ERIC Educational Resources Information Center

Miyakoda, Haruko

2008-01-01

Although many studies of speech errors have been presented in the literature, most have focused on errors occurring at either the segmental or feature level. Few, if any, studies have dealt with the prosodic structure of errors. This paper aims to fill this gap by taking up the issue of prosodic structure in Japanese speech errors, with a focus on…

Pressure gradient effects on heat transfer to reusable surface insulation tile-array gaps

NASA Technical Reports Server (NTRS)

Throckmorton, D. A.

1975-01-01

An experimental investigation was performed to determine the effect of pressure gradient on the heat transfer within space shuttle reusable surface insulation (RSI) tile-array gaps under thick, turbulent boundary-layer conditions. Heat-transfer and pressure measurements were obtained on a curved array of full-scale simulated RSI tiles in a tunnel-wall boundary layer at a nominal free-stream Mach number and free-stream Reynolds numbers. Transverse pressure gradients of varying degree were induced over the model surface by rotating the curved array with respect to the flow. Definition of the tunnel-wall boundary-layer flow was obtained by measurement of boundary-layer pitot pressure profiles, wall pressure, and heat transfer. Flat-plate heat-transfer data were correlated and a method was derived for prediction of heat transfer to a smooth curved surface in the highly three-dimensional tunnel-wall boundary-layer flow. Pressure on the floor of the RSI tile-array gap followed the trends of the external surface pressure. Heat transfer to the surface immediately downstream of a transverse gap is higher than that for a smooth surface at the same location. Heating to the wall of a transverse gap, and immediately downstream of it, at its intersection with a longitudinal gap is significantly greater than that for the simple transverse gap.

Drop short control of electrode gap

DOEpatents

Fisher, Robert W.; Maroone, James P.; Tipping, Donald W.; Zanner, Frank J.

1986-01-01

During vacuum consumable arc remelting the electrode gap between a consumable electrode and a pool of molten metal is difficult to control. The present invention monitors drop shorts by detecting a decrease in the voltage between the consumable electrode and molten pool. The drop shorts and their associated voltage reductions occur as repetitive pulses which are closely correlated to the electrode gap. Thus, the method and apparatus of the present invention controls electrode gap based upon drop shorts detected from the monitored anode-cathode voltage. The number of drop shorts are accumulated, and each time the number of drop shorts reach a predetermined number, the average period between drop shorts is calculated from this predetermined number and the time in which this number is accumulated. This average drop short period is used in a drop short period electrode gap model which determines the actual electrode gap from the drop short. The actual electrode gap is then compared with a desired electrode gap which is selected to produce optimum operating conditions and the velocity of the consumable error is varied based upon the gap error. The consumable electrode is driven according to any prior art system at this velocity. In the preferred embodiment, a microprocessor system is utilized to perform the necessary calculations and further to monitor the duration of each drop short. If any drop short exceeds a preset duration period, the consumable electrode is rapidly retracted a predetermined distance to prevent bonding of the consumable electrode to the molten remelt.

Convergence Rates for Multivariate Smoothing Spline Functions.

DTIC Science & Technology

1982-10-01

GAI (,T) g (T)dT - g In order to show convergence of the series and obtain bounds on the terms, we need to estimate £ Now (1 + Ay v) AyV ( g ,#V...Cox* Technical Summary Report #2437 October 1982 ABSTRACT Given data z i - g (ti ) + ci, 1 4 i 4 n, where g is the unknown function, the ti are unknown...d-dimensional variables in a domain fl, and the ei are i.i.d. random errors, the smoothing spline estimate g n is defined to be the

Motion compensated shape error concealment.

PubMed

Schuster, Guido M; Katsaggelos, Aggelos K

2006-02-01

The introduction of Video Objects (VOs) is one of the innovations of MPEG-4. The alpha-plane of a VO defines its shape at a given instance in time and hence determines the boundary of its texture. In packet-based networks, shape, motion, and texture are subject to loss. While there has been considerable attention paid to the concealment of texture and motion errors, little has been done in the field of shape error concealment. In this paper we propose a post-processing shape error concealment technique that uses the motion compensated boundary information of the previously received alpha-plane. The proposed approach is based on matching received boundary segments in the current frame to the boundary in the previous frame. This matching is achieved by finding a maximally smooth motion vector field. After the current boundary segments are matched to the previous boundary, the missing boundary pieces are reconstructed by motion compensation. Experimental results demonstrating the performance of the proposed motion compensated shape error concealment method, and comparing it with the previously proposed weighted side matching method are presented.

Visual enhancement of unmixed multispectral imagery using adaptive smoothing

USGS Publications Warehouse

Lemeshewsky, G.P.; Rahman, Z.-U.; Schowengerdt, R.A.; Reichenbach, S.E.

2004-01-01

Adaptive smoothing (AS) has been previously proposed as a method to smooth uniform regions of an image, retain contrast edges, and enhance edge boundaries. The method is an implementation of the anisotropic diffusion process which results in a gray scale image. This paper discusses modifications to the AS method for application to multi-band data which results in a color segmented image. The process was used to visually enhance the three most distinct abundance fraction images produced by the Lagrange constraint neural network learning-based unmixing of Landsat 7 Enhanced Thematic Mapper Plus multispectral sensor data. A mutual information-based method was applied to select the three most distinct fraction images for subsequent visualization as a red, green, and blue composite. A reported image restoration technique (partial restoration) was applied to the multispectral data to reduce unmixing error, although evaluation of the performance of this technique was beyond the scope of this paper. The modified smoothing process resulted in a color segmented image with homogeneous regions separated by sharpened, coregistered multiband edges. There was improved class separation with the segmented image, which has importance to subsequent operations involving data classification.

Robust Smoothing: Smoothing Parameter Selection and Applications to Fluorescence Spectroscopy∂

PubMed Central

Lee, Jong Soo; Cox, Dennis D.

2009-01-01

Fluorescence spectroscopy has emerged in recent years as an effective way to detect cervical cancer. Investigation of the data preprocessing stage uncovered a need for a robust smoothing to extract the signal from the noise. Various robust smoothing methods for estimating fluorescence emission spectra are compared and data driven methods for the selection of smoothing parameter are suggested. The methods currently implemented in R for smoothing parameter selection proved to be unsatisfactory, and a computationally efficient procedure that approximates robust leave-one-out cross validation is presented. PMID:20729976

Mechanism of Contact between a Droplet and an Atomically Smooth Substrate

NASA Astrophysics Data System (ADS)

Lo, Hau Yung; Liu, Yuan; Xu, Lei

2017-04-01

When a droplet gently lands on an atomically smooth substrate, it will most likely contact the underlying surface in about 0.1 s. However, theoretical estimation from fluid mechanics predicts a contact time of 10-100 s. What causes this large discrepancy, and how does nature speed up contact by 2 orders of magnitude? To probe this fundamental question, we prepare atomically smooth substrates by either coating a liquid film on glass or using a freshly cleaved mica surface, and visualize the droplet contact dynamics with 30-nm resolution. Interestingly, we discover two distinct speed-up approaches: (1) droplet skidding due to even minute perturbations breaks rotational symmetry and produces early contact at the thinnest gap location, and (2) for the unperturbed situation with rotational symmetry, a previously unnoticed boundary flow around only 0.1 mm /s expedites air drainage by over 1 order of magnitude. Together, these two mechanisms universally explain general contact phenomena on smooth substrates. The fundamental discoveries shed new light on contact and drainage research.

Diamond Smoothing Tools

NASA Technical Reports Server (NTRS)

Voronov, Oleg

2007-01-01

Diamond smoothing tools have been proposed for use in conjunction with diamond cutting tools that are used in many finish-machining operations. Diamond machining (including finishing) is often used, for example, in fabrication of precise metal mirrors. A diamond smoothing tool according to the proposal would have a smooth spherical surface. For a given finish machining operation, the smoothing tool would be mounted next to the cutting tool. The smoothing tool would slide on the machined surface left behind by the cutting tool, plastically deforming the surface material and thereby reducing the roughness of the surface, closing microcracks and otherwise generally reducing or eliminating microscopic surface and subsurface defects, and increasing the microhardness of the surface layer. It has been estimated that if smoothing tools of this type were used in conjunction with cutting tools on sufficiently precise lathes, it would be possible to reduce the roughness of machined surfaces to as little as 3 nm. A tool according to the proposal would consist of a smoothing insert in a metal holder. The smoothing insert would be made from a diamond/metal functionally graded composite rod preform, which, in turn, would be made by sintering together a bulk single-crystal or polycrystalline diamond, a diamond powder, and a metallic alloy at high pressure. To form the spherical smoothing tip, the diamond end of the preform would be subjected to flat grinding, conical grinding, spherical grinding using diamond wheels, and finally spherical polishing and/or buffing using diamond powders. If the diamond were a single crystal, then it would be crystallographically oriented, relative to the machining motion, to minimize its wear and maximize its hardness. Spherically polished diamonds could also be useful for purposes other than smoothing in finish machining: They would likely also be suitable for use as heat-resistant, wear-resistant, unlubricated sliding-fit bearing inserts.

Critical older driver errors in a national sample of serious U.S. crashes.

PubMed

Cicchino, Jessica B; McCartt, Anne T

2015-07-01

Older drivers are at increased risk of crash involvement per mile traveled. The purpose of this study was to examine older driver errors in serious crashes to determine which errors are most prevalent. The National Highway Traffic Safety Administration's National Motor Vehicle Crash Causation Survey collected in-depth, on-scene data for a nationally representative sample of 5470 U.S. police-reported passenger vehicle crashes during 2005-2007 for which emergency medical services were dispatched. There were 620 crashes involving 647 drivers aged 70 and older, representing 250,504 crash-involved older drivers. The proportion of various critical errors made by drivers aged 70 and older were compared with those made by drivers aged 35-54. Driver error was the critical reason for 97% of crashes involving older drivers. Among older drivers who made critical errors, the most common were inadequate surveillance (33%) and misjudgment of the length of a gap between vehicles or of another vehicle's speed, illegal maneuvers, medical events, and daydreaming (6% each). Inadequate surveillance (33% vs. 22%) and gap or speed misjudgment errors (6% vs. 3%) were more prevalent among older drivers than middle-aged drivers. Seventy-one percent of older drivers' inadequate surveillance errors were due to looking and not seeing another vehicle or failing to see a traffic control rather than failing to look, compared with 40% of inadequate surveillance errors among middle-aged drivers. About two-thirds (66%) of older drivers' inadequate surveillance errors and 77% of their gap or speed misjudgment errors were made when turning left at intersections. When older drivers traveled off the edge of the road or traveled over the lane line, this was most commonly due to non-performance errors such as medical events (51% and 44%, respectively), whereas middle-aged drivers were involved in these crash types for other reasons. Gap or speed misjudgment errors and inadequate surveillance errors were

Standard Errors of Equating for the Percentile Rank-Based Equipercentile Equating with Log-Linear Presmoothing

ERIC Educational Resources Information Center

Wang, Tianyou

2009-01-01

Holland and colleagues derived a formula for analytical standard error of equating using the delta-method for the kernel equating method. Extending their derivation, this article derives an analytical standard error of equating procedure for the conventional percentile rank-based equipercentile equating with log-linear smoothing. This procedure is…

Systematic study of error sources in supersonic skin-friction balance measurements

NASA Technical Reports Server (NTRS)

Allen, J. M.

1976-01-01

An experimental study was performed to investigate potential error sources in data obtained with a self-nulling, moment-measuring, skin-friction balance. The balance was installed in the sidewall of a supersonic wind tunnel, and independent measurements of the three forces contributing to the balance output (skin friction, lip force, and off-center normal force) were made for a range of gap size and element protrusion. The relatively good agreement between the balance data and the sum of these three independently measured forces validated the three-term model used. No advantage to a small gap size was found; in fact, the larger gaps were preferable. Perfect element alignment with the surrounding test surface resulted in very small balance errors. However, if small protrusion errors are unavoidable, no advantage was found in having the element slightly below the surrounding test surface rather than above it.

An opening criterion for dust gaps in protoplanetary discs

NASA Astrophysics Data System (ADS)

Dipierro, Giovanni; Laibe, Guillaume

2017-08-01

We aim to understand under which conditions a low-mass planet can open a gap in viscous dusty protoplanetary discs. For this purpose, we extend the theory of dust radial drift to include the contribution from the tides of an embedded planet and from the gas viscous forces. From this formalism, we derive (I) a grain-size-dependent criterion for dust gap opening in discs, (II) an estimate of the location of the outer edge of the dust gap and (III) an estimate of the minimum Stokes number above which low-mass planets are able to carve gaps that appear only in the dust disc. These analytical estimates are particularly helpful to appraise the minimum mass of a hypothetical planet carving gaps in discs observed at long wavelengths and high resolution. We validate the theory against 3D smoothed particle hydrodynamics simulations of planet-disc interaction in a broad range of dusty protoplanetary discs. We find a remarkable agreement between the theoretical model and the numerical experiments.

A Fast Smoothing Algorithm for Post-Processing of Surface Reflectance Spectra Retrieved from Airborne Imaging Spectrometer Data

PubMed Central

Gao, Bo-Cai; Liu, Ming

2013-01-01

Surface reflectance spectra retrieved from remotely sensed hyperspectral imaging data using radiative transfer models often contain residual atmospheric absorption and scattering effects. The reflectance spectra may also contain minor artifacts due to errors in radiometric and spectral calibrations. We have developed a fast smoothing technique for post-processing of retrieved surface reflectance spectra. In the present spectral smoothing technique, model-derived reflectance spectra are first fit using moving filters derived with a cubic spline smoothing algorithm. A common gain curve, which contains minor artifacts in the model-derived reflectance spectra, is then derived. This gain curve is finally applied to all of the reflectance spectra in a scene to obtain the spectrally smoothed surface reflectance spectra. Results from analysis of hyperspectral imaging data collected with the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data are given. Comparisons between the smoothed spectra and those derived with the empirical line method are also presented. PMID:24129022

Role of pp60(c-src) and p(44/42) MAPK in ANG II-induced contraction of rat tonic gastrointestinal smooth muscles.

PubMed

Puri, Rajinder N; Fan, Ya-Ping; Rattan, Satish

2002-08-01

We examined the role of mitogen-activated protein kinase (p(44/42) MAPK) in ANG II-induced contraction of lower esophageal sphincter (LES) and internal anal sphincter (IAS) smooth muscles. Studies were performed in the isolated smooth muscles and cells (SMC). ANG II-induced changes in the levels of phosphorylation of different signal transduction and effector proteins were determined before and after selective inhibitors. ANG II-induced contraction of the rat LES and IAS SMC was inhibited by genistein, PD-98059 [a specific inhibitor of MAPK kinases (MEK 1/2)], herbimycin A (a pp60(c-src) inhibitor), and antibodies to pp60(c-src) and p(120) ras GTPase-activating protein (p(120) rasGAP). ANG II-induced contraction of the tonic smooth muscles was accompanied by an increase in tyrosine phosphorylation of p(120) rasGAP. These were attenuated by genistein but not by PD-98059. ANG II-induced increase in phosphorylations of p(44/42) MAPKs and caldesmon was attenuated by both genistein and PD-98059. We conclude that pp60(c-src) and p(44/42) MAPKs play an important role in ANG II-induced contraction of LES and IAS smooth muscles.

Voltage-Clamp Studies on Uterine Smooth Muscle

PubMed Central

Anderson, Nels C.

1969-01-01

These studies have developed and tested an experimental approach to the study of membrane ionic conductance mechanisms in strips of uterine smooth muscle. The experimental and theoretical basis for applying the double sucrose-gap technique is described along with the limitations of this system. Nonpropagating membrane action potentials were produced in response to depolarizing current pulses under current-clamp conditions. The stepwise change of membrane potential under voltage-clamp conditions resulted in a family of ionic currents with voltage- and time-dependent characteristics. In sodium-free solution the peak transient current decreased and its equilibrium potential shifted along the voltage axis toward a more negative internal potential. These studies indicate a sodium-dependent, regenerative excitation mechanism. PMID:5796366

Antisaccade and smooth pursuit eye movements in healthy subjects receiving sertraline and lorazepam.

PubMed

Green, J F; King, D J; Trimble, K M

2000-03-01

Patients suffering from some psychiatric and neurological disorders demonstrate abnormally high levels of saccadic distractibility when carrying out the antisaccade task. This has been particularly thoroughly demonstrated in patients with schizophrenia. A large body of evidence has been accumulated from studies of patients which suggests that such eye movement abnormalities may arise from frontal lobe dysfunction. The psychopharmacology of saccadic distractibility is less well understood, but is relevant both to interpreting patient studies and to establishing the neurological basis of their findings. Twenty healthy subjects received lorazepam 0.5 mg, 1 mg and 2 mg, sertraline 50 mg and placebo in a balanced, repeated measures study design. Antisaccade, no-saccade, visually guided saccade and smooth pursuit tasks were carried out and the effects of practice and drugs measured. Lorazepam increased direction errors in the antisaccade and no-saccade tasks in a dose-dependent manner. Sertraline had no effect on these measures. Correlation showed a statistically significant, but rather weak, association between direction errors and smooth pursuit measures. Practice was shown to have a powerful effect on antisaccade direction errors. This study supports our previous work by confirming that lorazepam reliably worsens saccadic distractibility, in contrast to other psychotropic drugs such as sertraline and chlorpromazine. Our results also suggest that other studies in this field, particularly those using parallel groups design, should take account of practice effects.

Bayesian multi-scale smoothing of photon-limited images with applications to astronomy and medicine

NASA Astrophysics Data System (ADS)

White, John

Multi-scale models for smoothing Poisson signals or images have gained much attention over the past decade. A new Bayesian model is developed using the concept of the Chinese restaurant process to find structures in two-dimensional images when performing image reconstruction or smoothing. This new model performs very well when compared to other leading methodologies for the same problem. It is developed and evaluated theoretically and empirically throughout Chapter 2. The newly developed Bayesian model is extended to three-dimensional images in Chapter 3. The third dimension has numerous different applications, such as different energy spectra, another spatial index, or possibly a temporal dimension. Empirically, this method shows promise in reducing error with the use of simulation studies. A further development removes background noise in the image. This removal can further reduce the error and is done using a modeling adjustment and post-processing techniques. These details are given in Chapter 4. Applications to real world problems are given throughout. Photon-based images are common in astronomical imaging due to the collection of different types of energy such as X-Rays. Applications to real astronomical images are given, and these consist of X-ray images from the Chandra X-ray observatory satellite. Diagnostic medicine uses many types of imaging such as magnetic resonance imaging and computed tomography that can also benefit from smoothing techniques such as the one developed here. Reducing the amount of radiation a patient takes will make images more noisy, but this can be mitigated through the use of image smoothing techniques. Both types of images represent the potential real world use for these methods.

Discrete wavelet transform: a tool in smoothing kinematic data.

PubMed

Ismail, A R; Asfour, S S

1999-03-01

Motion analysis systems typically introduce noise to the displacement data recorded. Butterworth digital filters have been used to smooth the displacement data in order to obtain smoothed velocities and accelerations. However, this technique does not yield satisfactory results, especially when dealing with complex kinematic motions that occupy the low- and high-frequency bands. The use of the discrete wavelet transform, as an alternative to digital filters, is presented in this paper. The transform passes the original signal through two complementary low- and high-pass FIR filters and decomposes the signal into an approximation function and a detail function. Further decomposition of the signal results in transforming the signal into a hierarchy set of orthogonal approximation and detail functions. A reverse process is employed to perfectly reconstruct the signal (inverse transform) back from its approximation and detail functions. The discrete wavelet transform was applied to the displacement data recorded by Pezzack et al., 1977. The smoothed displacement data were twice differentiated and compared to Pezzack et al.'s acceleration data in order to choose the most appropriate filter coefficients and decomposition level on the basis of maximizing the percentage of retained energy (PRE) and minimizing the root mean square error (RMSE). Daubechies wavelet of the fourth order (Db4) at the second decomposition level showed better results than both the biorthogonal and Coiflet wavelets (PRE = 97.5%, RMSE = 4.7 rad s-2). The Db4 wavelet was then used to compress complex displacement data obtained from a noisy mathematically generated function. Results clearly indicate superiority of this new smoothing approach over traditional filters.

StreamMap: Smooth Dynamic Visualization of High-Density Streaming Points.

PubMed

Li, Chenhui; Baciu, George; Han, Yu

2018-03-01

Interactive visualization of streaming points for real-time scatterplots and linear blending of correlation patterns is increasingly becoming the dominant mode of visual analytics for both big data and streaming data from active sensors and broadcasting media. To better visualize and interact with inter-stream patterns, it is generally necessary to smooth out gaps or distortions in the streaming data. Previous approaches either animate the points directly or present a sampled static heat-map. We propose a new approach, called StreamMap, to smoothly blend high-density streaming points and create a visual flow that emphasizes the density pattern distributions. In essence, we present three new contributions for the visualization of high-density streaming points. The first contribution is a density-based method called super kernel density estimation that aggregates streaming points using an adaptive kernel to solve the overlapping problem. The second contribution is a robust density morphing algorithm that generates several smooth intermediate frames for a given pair of frames. The third contribution is a trend representation design that can help convey the flow directions of the streaming points. The experimental results on three datasets demonstrate the effectiveness of StreamMap when dynamic visualization and visual analysis of trend patterns on streaming points are required.

Error analysis and correction in wavefront reconstruction from the transport-of-intensity equation

PubMed Central

Barbero, Sergio; Thibos, Larry N.

2007-01-01

Wavefront reconstruction from the transport-of-intensity equation (TIE) is a well-posed inverse problem given smooth signals and appropriate boundary conditions. However, in practice experimental errors lead to an ill-condition problem. A quantitative analysis of the effects of experimental errors is presented in simulations and experimental tests. The relative importance of numerical, misalignment, quantization, and photodetection errors are shown. It is proved that reduction of photodetection noise by wavelet filtering significantly improves the accuracy of wavefront reconstruction from simulated and experimental data. PMID:20052302

Compact disk error measurements

NASA Technical Reports Server (NTRS)

Howe, D.; Harriman, K.; Tehranchi, B.

1993-01-01

The objectives of this project are as follows: provide hardware and software that will perform simple, real-time, high resolution (single-byte) measurement of the error burst and good data gap statistics seen by a photoCD player read channel when recorded CD write-once discs of variable quality (i.e., condition) are being read; extend the above system to enable measurement of the hard decision (i.e., 1-bit error flags) and soft decision (i.e., 2-bit error flags) decoding information that is produced/used by the Cross Interleaved - Reed - Solomon - Code (CIRC) block decoder employed in the photoCD player read channel; construct a model that uses data obtained via the systems described above to produce meaningful estimates of output error rates (due to both uncorrected ECC words and misdecoded ECC words) when a CD disc having specific (measured) error statistics is read (completion date to be determined); and check the hypothesis that current adaptive CIRC block decoders are optimized for pressed (DAD/ROM) CD discs. If warranted, do a conceptual design of an adaptive CIRC decoder that is optimized for write-once CD discs.

Smooth interface effects on the confinement properties of GaSb/Al xGa 1- xSb quantum wells

NASA Astrophysics Data System (ADS)

Adib, Artur B.; de Sousa, Jeanlex S.; Farias, Gil A.; Freire, Valder N.

2000-10-01

A theoretical investigation on the confinement properties of GaSb/Al xGa 1- xSb single quantum wells (QWs) with smooth interfaces is performed. Error function ( erf)-like interfacial aluminum molar fraction variations in the QWs, from which it is possible to obtain the carriers effective masses and confinement potential profiles, are assumed. It is shown that the existence of smooth interfaces blue shifts considerably the confined carriers and exciton energies, an effect which is stronger in thin QWs.

Medication errors in residential aged care facilities: a distributed cognition analysis of the information exchange process.

PubMed

Tariq, Amina; Georgiou, Andrew; Westbrook, Johanna

2013-05-01

Medication safety is a pressing concern for residential aged care facilities (RACFs). Retrospective studies in RACF settings identify inadequate communication between RACFs, doctors, hospitals and community pharmacies as the major cause of medication errors. Existing literature offers limited insight about the gaps in the existing information exchange process that may lead to medication errors. The aim of this research was to explicate the cognitive distribution that underlies RACF medication ordering and delivery to identify gaps in medication-related information exchange which lead to medication errors in RACFs. The study was undertaken in three RACFs in Sydney, Australia. Data were generated through ethnographic field work over a period of five months (May-September 2011). Triangulated analysis of data primarily focused on examining the transformation and exchange of information between different media across the process. The findings of this study highlight the extensive scope and intense nature of information exchange in RACF medication ordering and delivery. Rather than attributing error to individual care providers, the explication of distributed cognition processes enabled the identification of gaps in three information exchange dimensions which potentially contribute to the occurrence of medication errors namely: (1) design of medication charts which complicates order processing and record keeping (2) lack of coordination mechanisms between participants which results in misalignment of local practices (3) reliance on restricted communication bandwidth channels mainly telephone and fax which complicates the information processing requirements. The study demonstrates how the identification of these gaps enhances understanding of medication errors in RACFs. Application of the theoretical lens of distributed cognition can assist in enhancing our understanding of medication errors in RACFs through identification of gaps in information exchange. Understanding

A method to estimate the additional uncertainty in gap-filled NEE resulting from long gaps in the CO2 flux record

Treesearch

Andrew D. Richardson; David Y. Hollinger

2007-01-01

Missing values in any data set create problems for researchers. The process by which missing values are replaced, and the data set is made complete, is generally referred to as imputation. Within the eddy flux community, the term "gap filling" is more commonly applied. A major challenge is that random errors in measured data result in uncertainty in the gap-...

Stimulated Raman and Brillouin scattering of polarization-smoothed and temporally smoothed laser beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, R.L.; Lefebvre, E.; Langdon, A.B.

1999-04-01

Control of filamentation and stimulated Raman and Brillouin scattering is shown to be possible by use of both spatial and temporal smoothing schemes. The spatial smoothing is accomplished by the use of phase plates [Y. Kato and K. Mima, Appl. Phys. {bold 329}, 186 (1982)] and polarization smoothing [Lefebvre {ital et al.}, Phys. Plasmas {bold 5}, 2701 (1998)] in which the plasma is irradiated with two orthogonally polarized, uncorrelated speckle patterns. The temporal smoothing considered here is smoothing by spectral dispersion [Skupsky {ital et al.}, J. Appl. Phys. {bold 66}, 3456 (1989)] in which the speckle pattern changes on themore » laser coherence time scale. At the high instability gains relevant to laser fusion experiments, the effect of smoothing must include the competition among all three instabilities. {copyright} {ital 1999 American Institute of Physics.}« less

Role of retinal slip in the prediction of target motion during smooth and saccadic pursuit.

PubMed

de Brouwer, S; Missal, M; Lefèvre, P

2001-08-01

Visual tracking of moving targets requires the combination of smooth pursuit eye movements with catch-up saccades. In primates, catch-up saccades usually take place only during pursuit initiation because pursuit gain is close to unity. This contrasts with the lower and more variable gain of smooth pursuit in cats, where smooth eye movements are intermingled with catch-up saccades during steady-state pursuit. In this paper, we studied in detail the role of retinal slip in the prediction of target motion during smooth and saccadic pursuit in the cat. We found that the typical pattern of pursuit in the cat was a combination of smooth eye movements with saccades. During smooth pursuit initiation, there was a correlation between peak eye acceleration and target velocity. During pursuit maintenance, eye velocity oscillated at approximately 3 Hz around a steady-state value. The average gain of smooth pursuit was approximately 0.5. Trained cats were able to continue pursuing in the absence of a visible target, suggesting a role of the prediction of future target motion in this species. The analysis of catch-up saccades showed that the smooth-pursuit motor command is added to the saccadic command during catch-up saccades and that both position error and retinal slip are taken into account in their programming. The influence of retinal slip on catch-up saccades showed that prediction about future target motion is used in the programming of catch-up saccades. Altogether, these results suggest that pursuit systems in primates and cats are qualitatively similar, with a lower average gain in the cat and that prediction affects both saccades and smooth eye movements during pursuit.

smoothG

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barker, Andrew T.; Gelever, Stephan A.; Lee, Chak S.

2017-12-12

smoothG is a collection of parallel C++ classes/functions that algebraically constructs reduced models of different resolutions from a given high-fidelity graph model. In addition, smoothG also provides efficient linear solvers for the reduced models. Other than pure graph problem, the software finds its application in subsurface flow and power grid simulations in which graph Laplacians are found

Memory and decision making in the frontal cortex during visual motion processing for smooth pursuit eye movements.

PubMed

Shichinohe, Natsuko; Akao, Teppei; Kurkin, Sergei; Fukushima, Junko; Kaneko, Chris R S; Fukushima, Kikuro

2009-06-11

Cortical motor areas are thought to contribute "higher-order processing," but what that processing might include is unknown. Previous studies of the smooth pursuit-related discharge of supplementary eye field (SEF) neurons have not distinguished activity associated with the preparation for pursuit from discharge related to processing or memory of the target motion signals. Using a memory-based task designed to separate these components, we show that the SEF contains signals coding retinal image-slip-velocity, memory, and assessment of visual motion direction, the decision of whether to pursue, and the preparation for pursuit eye movements. Bilateral muscimol injection into SEF resulted in directional errors in smooth pursuit, errors of whether to pursue, and impairment of initial correct eye movements. These results suggest an important role for the SEF in memory and assessment of visual motion direction and the programming of appropriate pursuit eye movements.

Sources of Error in Substance Use Prevalence Surveys

PubMed Central

Johnson, Timothy P.

2014-01-01

Population-based estimates of substance use patterns have been regularly reported now for several decades. Concerns with the quality of the survey methodologies employed to produce those estimates date back almost as far. Those concerns have led to a considerable body of research specifically focused on understanding the nature and consequences of survey-based errors in substance use epidemiology. This paper reviews and summarizes that empirical research by organizing it within a total survey error model framework that considers multiple types of representation and measurement errors. Gaps in our knowledge of error sources in substance use surveys and areas needing future research are also identified. PMID:27437511

Income Smoothing: Methodology and Models.

DTIC Science & Technology

1986-05-01

studies have all followed a similar research process (Figure 1). All were expost studies and included the following steps: 1. A smoothing technique(s) or...researcher methodological decisions used in past empirical studies of income smoothing (design type, smoothing device norm, and income target) are discussed...behavior. The identification of smoothing, and consequently the conclusions to be drawn from smoothing studies , is found to be sensitive to the three

Does rat granulation tissue maturation involve gap junction communications?

PubMed

Au, Katherine; Ehrlich, H Paul

2007-07-01

Wound healing, a coordinated process, proceeds by sequential changes in cell differentiation and terminates with the deposition of a new connective tissue matrix, a scar. Initially, there is the migratory fibroblast, followed by the proliferative fibroblast, then the synthetic fibroblast, which transforms into the myofibroblast, and finally the apoptotic fibroblast. Gap junction intercellular communications are proposed to coordinate the stringent control of fibroblast phenotypic changes. Does added oleamide, a natural fatty acid that blocks gap junction intercellular communications, alter the phenotypic progression of wound fibroblasts? Pairs of polyvinyl alcohol sponges attached to Alzet pumps, which constantly pumped either oleamide or vehicle solvent, were implanted subcutaneously into three rats. On day 8, implants were harvested and evaluated histologically and biochemically. The capsule of oleamide-treated sponge contained closely packed fibroblasts with little connective tissue between them. The birefringence intensity of that connective tissue was reduced, indicating a reduced density of collagen fiber bundles. Myofibroblasts, identified immunohistologically by alpha-smooth muscle actin-stained stress fibers, were reduced in oleamide-treated implants. Western blot analysis showing less alpha-smooth muscle actin confirmed the reduced density of myofibroblasts. It appears that oleamide retards the progression of wound repair, where less connective tissue is deposited, the collagen is less organized, and the appearance of myofibroblasts is impaired. These findings support the hypothesis that gap junction intercellular communications between wound fibroblasts in granulation tissue play a role in the progression of repair and the maturation of granulation tissue into scar.

Bellman's GAP--a language and compiler for dynamic programming in sequence analysis.

PubMed

Sauthoff, Georg; Möhl, Mathias; Janssen, Stefan; Giegerich, Robert

2013-03-01

Dynamic programming is ubiquitous in bioinformatics. Developing and implementing non-trivial dynamic programming algorithms is often error prone and tedious. Bellman's GAP is a new programming system, designed to ease the development of bioinformatics tools based on the dynamic programming technique. In Bellman's GAP, dynamic programming algorithms are described in a declarative style by tree grammars, evaluation algebras and products formed thereof. This bypasses the design of explicit dynamic programming recurrences and yields programs that are free of subscript errors, modular and easy to modify. The declarative modules are compiled into C++ code that is competitive to carefully hand-crafted implementations. This article introduces the Bellman's GAP system and its language, GAP-L. It then demonstrates the ease of development and the degree of re-use by creating variants of two common bioinformatics algorithms. Finally, it evaluates Bellman's GAP as an implementation platform of 'real-world' bioinformatics tools. Bellman's GAP is available under GPL license from http://bibiserv.cebitec.uni-bielefeld.de/bellmansgap. This Web site includes a repository of re-usable modules for RNA folding based on thermodynamics.

Effect of data gaps on correlation dimension computed from light curves of variable stars

NASA Astrophysics Data System (ADS)

George, Sandip V.; Ambika, G.; Misra, R.

2015-11-01

Observational data, especially astrophysical data, is often limited by gaps in data that arises due to lack of observations for a variety of reasons. Such inadvertent gaps are usually smoothed over using interpolation techniques. However the smoothing techniques can introduce artificial effects, especially when non-linear analysis is undertaken. We investigate how gaps can affect the computed values of correlation dimension of the system, without using any interpolation. For this we introduce gaps artificially in synthetic data derived from standard chaotic systems, like the Rössler and Lorenz, with frequency of occurrence and size of missing data drawn from two Gaussian distributions. Then we study the changes in correlation dimension with change in the distributions of position and size of gaps. We find that for a considerable range of mean gap frequency and size, the value of correlation dimension is not significantly affected, indicating that in such specific cases, the calculated values can still be reliable and acceptable. Thus our study introduces a method of checking the reliability of computed correlation dimension values by calculating the distribution of gaps with respect to its size and position. This is illustrated for the data from light curves of three variable stars, R Scuti, U Monocerotis and SU Tauri. We also demonstrate how a cubic spline interpolation can cause a time series of Gaussian noise with missing data to be misinterpreted as being chaotic in origin. This is demonstrated for the non chaotic light curve of variable star SS Cygni, which gives a saturated D2 value, when interpolated using a cubic spline. In addition we also find that a careful choice of binning, in addition to reducing noise, can help in shifting the gap distribution to the reliable range for D2 values.

A New Filtering and Smoothing Algorithm for Railway Track Surveying Based on Landmark and IMU/Odometer

PubMed Central

Jiang, Qingan; Wu, Wenqi; Jiang, Mingming; Li, Yun

2017-01-01

High-accuracy railway track surveying is essential for railway construction and maintenance. The traditional approaches based on total station equipment are not efficient enough since high precision surveying frequently needs static measurements. This paper proposes a new filtering and smoothing algorithm based on the IMU/odometer and landmarks integration for the railway track surveying. In order to overcome the difficulty of estimating too many error parameters with too few landmark observations, a new model with completely observable error states is established by combining error terms of the system. Based on covariance analysis, the analytical relationship between the railway track surveying accuracy requirements and equivalent gyro drifts including bias instability and random walk noise are established. Experiment results show that the accuracy of the new filtering and smoothing algorithm for railway track surveying can reach 1 mm (1σ) when using a Ring Laser Gyroscope (RLG)-based Inertial Measurement Unit (IMU) with gyro bias instability of 0.03°/h and random walk noise of 0.005°/h while control points of the track control network (CPIII) position observations are provided by the optical total station in about every 60 m interval. The proposed approach can satisfy at the same time the demands of high accuracy and work efficiency for railway track surveying. PMID:28629191

Closing the Achievement Gap as Addressed in Student Support Programs

ERIC Educational Resources Information Center

Gordon, Vincent Hoover Adams, Jr.

2012-01-01

This research will focus on three components: (1) factors contributing to the achievement gap, (2) common errors made by policy makers with regard to school reform, and (3) recommendations to educators, policy makers, and parents on closing the achievement gap through results-based student support programs. Examples of each of the three components…

Porous plug for reducing orifice induced pressure error in airfoils

NASA Technical Reports Server (NTRS)

Plentovich, Elizabeth B. (Inventor); Gloss, Blair B. (Inventor); Eves, John W. (Inventor); Stack, John P. (Inventor)

1988-01-01

A porous plug is provided for the reduction or elimination of positive error caused by the orifice during static pressure measurements of airfoils. The porous plug is press fitted into the orifice, thereby preventing the error caused either by fluid flow turning into the exposed orifice or by the fluid flow stagnating at the downstream edge of the orifice. In addition, the porous plug is made flush with the outer surface of the airfoil, by filing and polishing, to provide a smooth surface which alleviates the error caused by imperfections in the orifice. The porous plug is preferably made of sintered metal, which allows air to pass through the pores, so that the static pressure measurements can be made by remote transducers.

Types of diagnostic errors in neurological emergencies in the emergency department.

PubMed

Dubosh, Nicole M; Edlow, Jonathan A; Lefton, Micah; Pope, Jennifer V

2015-02-01

Neurological emergencies often pose diagnostic challenges for emergency physicians because these patients often present with atypical symptoms and standard imaging tests are imperfect. Misdiagnosis occurs due to a variety of errors. These can be classified as knowledge gaps, cognitive errors, and systems-based errors. The goal of this study was to describe these errors through review of quality assurance (QA) records. This was a retrospective pilot study of patients with neurological emergency diagnoses that were missed or delayed at one urban, tertiary academic emergency department. Cases meeting inclusion criteria were identified through review of QA records. Three emergency physicians independently reviewed each case and determined the type of error that led to the misdiagnosis. Proportions, confidence intervals, and a reliability coefficient were calculated. During the study period, 1168 cases were reviewed. Forty-two cases were found to include a neurological misdiagnosis and twenty-nine were determined to be the result of an error. The distribution of error types was as follows: knowledge gap 45.2% (95% CI 29.2, 62.2), cognitive error 29.0% (95% CI 15.9, 46.8), and systems-based error 25.8% (95% CI 13.5, 43.5). Cerebellar strokes were the most common type of stroke misdiagnosed, accounting for 27.3% of missed strokes. All three error types contributed to the misdiagnosis of neurological emergencies. Misdiagnosis of cerebellar lesions and erroneous radiology resident interpretations of neuroimaging were the most common mistakes. Understanding the types of errors may enable emergency physicians to develop possible solutions and avoid them in the future.

Validity of the two-level model for Viterbi decoder gap-cycle performance

NASA Technical Reports Server (NTRS)

Dolinar, S.; Arnold, S.

1990-01-01

A two-level model has previously been proposed for approximating the performance of a Viterbi decoder which encounters data received with periodically varying signal-to-noise ratio. Such cyclically gapped data is obtained from the Very Large Array (VLA), either operating as a stand-alone system or arrayed with Goldstone. This approximate model predicts that the decoder error rate will vary periodically between two discrete levels with the same period as the gap cycle. It further predicts that the length of the gapped portion of the decoder error cycle for a constraint length K decoder will be about K-1 bits shorter than the actual duration of the gap. The two-level model for Viterbi decoder performance with gapped data is subjected to detailed validation tests. Curves showing the cyclical behavior of the decoder error burst statistics are compared with the simple square-wave cycles predicted by the model. The validity of the model depends on a parameter often considered irrelevant in the analysis of Viterbi decoder performance, the overall scaling of the received signal or the decoder's branch-metrics. Three scaling alternatives are examined: optimum branch-metric scaling and constant branch-metric scaling combined with either constant noise-level scaling or constant signal-level scaling. The simulated decoder error cycle curves roughly verify the accuracy of the two-level model for both the case of optimum branch-metric scaling and the case of constant branch-metric scaling combined with constant noise-level scaling. However, the model is not accurate for the case of constant branch-metric scaling combined with constant signal-level scaling.

Altimeter error sources at the 10-cm performance level

NASA Technical Reports Server (NTRS)

Martin, C. F.

1977-01-01

Error sources affecting the calibration and operational use of a 10 cm altimeter are examined to determine the magnitudes of current errors and the investigations necessary to reduce them to acceptable bounds. Errors considered include those affecting operational data pre-processing, and those affecting altitude bias determination, with error budgets developed for both. The most significant error sources affecting pre-processing are bias calibration, propagation corrections for the ionosphere, and measurement noise. No ionospheric models are currently validated at the required 10-25% accuracy level. The optimum smoothing to reduce the effects of measurement noise is investigated and found to be on the order of one second, based on the TASC model of geoid undulations. The 10 cm calibrations are found to be feasible only through the use of altimeter passes that are very high elevation for a tracking station which tracks very close to the time of altimeter track, such as a high elevation pass across the island of Bermuda. By far the largest error source, based on the current state-of-the-art, is the location of the island tracking station relative to mean sea level in the surrounding ocean areas.

Airway mechanics and methods used to visualize smooth muscle dynamics in vitro.

PubMed

Cooper, P R; McParland, B E; Mitchell, H W; Noble, P B; Politi, A Z; Ressmeyer, A R; West, A R

2009-10-01

Contraction of airway smooth muscle (ASM) is regulated by the physiological, structural and mechanical environment in the lung. We review two in vitro techniques, lung slices and airway segment preparations, that enable in situ ASM contraction and airway narrowing to be visualized. Lung slices and airway segment approaches bridge a gap between cell culture and isolated ASM, and whole animal studies. Imaging techniques enable key upstream events involved in airway narrowing, such as ASM cell signalling and structural and mechanical events impinging on ASM, to be investigated.

Thin film GaP for solar cell application

NASA Astrophysics Data System (ADS)

Morozov, I. A.; Gudovskikh, A. S.; Kudryashov, D. A.; Nikitina, E. V.; Kleider, J.-P.; Myasoedov, A. V.; Levitskiy, V.

2016-08-01

A new approach to the silicon based heterostructures technology consisting of the growth of III-V compounds (GaP) on a silicon substrate by low-temperature plasma enhanced atomic layer deposition (PE-ALD) is proposed. The basic idea of the method is to use a time modulation of the growth process, i.e. time separated stages of atoms or precursors transport to the growing surface, migration over the surface, and crystal lattice relaxation for each monolayer. The GaP layers were grown on Si substrates by PE-ALD at 350°C with phosphine (PH3) and trimethylgallium (TMG) as sources of III and V atoms. Scanning and transmission electron microscopy demonstrate that the grown GaP films have homogeneous amorphous structure, smooth surface and a sharp GaP/Si interface. The GaP/Si heterostructures obtained by PE-ALD compare favourably to that conventionally grown by molecular beam epitaxy (MBE). Indeed, spectroscopic ellipsometry measurements indicate similar interband optical absorption while photoluminescence measurements indicate higher charge carrier effective lifetime. The better passivation properties of GaP layers grown by PE-ALD demonstrate a potential of this technology for new silicon based photovoltaic heterostructure

Enhanced spontaneous Ca2+ events in endothelial cells reflect signalling through myoendothelial gap junctions in pressurized mesenteric arteries.

PubMed

Kansui, Yasuo; Garland, Christopher J; Dora, Kim A

2008-08-01

Increases in global Ca(2+) in the endothelium are a crucial step in releasing relaxing factors to modulate arterial tone. In the present study we investigated spontaneous Ca(2+) events in endothelial cells, and the contribution of smooth muscle cells to these Ca(2+) events, in pressurized rat mesenteric resistance arteries. Spontaneous Ca(2+) events were observed under resting conditions in 34% of cells. These Ca(2+) events were absent in arteries preincubated with either cyclopiazonic acid or U-73122, but were unaffected by ryanodine or nicotinamide. Stimulation of smooth muscle cell depolarization and contraction with either phenylephrine or high concentrations of KCl significantly increased the frequency of endothelial cell Ca(2+) events. The putative gap junction uncouplers carbenoxolone and 18alpha-glycyrrhetinic acid each inhibited spontaneous and evoked Ca(2+) events, and the movement of calcein from endothelial to smooth muscle cells. In addition, spontaneous Ca(2+) events were diminished by nifedipine, lowering extracellular Ca(2+) levels, or by blockers of non-selective Ca(2+) influx pathways. These findings suggest that in pressurized rat mesenteric arteries, spontaneous Ca(2+) events in the endothelial cells appear to originate from endoplasmic reticulum IP(3) receptors, and are subject to regulation by surrounding smooth muscle cells via myoendothelial gap junctions, even under basal conditions.

A New and Fast Method for Smoothing Spectral Imaging Data

NASA Technical Reports Server (NTRS)

Gao, Bo-Cai; Liu, Ming; Davis, Curtiss O.

1998-01-01

The Airborne Visible Infrared Imaging Spectrometer (AVIRIS) acquires spectral imaging data covering the 0.4 - 2.5 micron wavelength range in 224 10-nm-wide channels from a NASA ER-2 aircraft at 20 km. More than half of the spectral region is affected by atmospheric gaseous absorption. Over the past decade, several techniques have been used to remove atmospheric effects from AVIRIS data for the derivation of surface reflectance spectra. An operational atmosphere removal algorithm (ATREM), which is based on theoretical modeling of atmospheric absorption and scattering effects, has been developed and updated for deriving surface reflectance spectra from AVIRIS data. Due to small errors in assumed wavelengths and errors in line parameters compiled on the HITRAN database, small spikes (particularly near the centers of the 0.94- and 1.14-micron water vapor bands) are present in this spectrum. Similar small spikes are systematically present in entire ATREM output cubes. These spikes have distracted geologists who are interested in studying surface mineral features. A method based on the "global" fitting of spectra with low order polynomials or other functions for removing these weak spikes has recently been developed by Boardman (this volume). In this paper, we describe another technique, which fits spectra "locally" based on cubic spline smoothing, for quick post processing of ATREM apparent reflectance spectra derived from AVIRIS data. Results from our analysis of AVIRIS data acquired over Cuprite mining district in Nevada in June of 1995 are given. Comparisons between our smoothed spectra and those derived with the empirical line method are presented.

On using smoothing spline and residual correction to fuse rain gauge observations and remote sensing data

NASA Astrophysics Data System (ADS)

Huang, Chengcheng; Zheng, Xiaogu; Tait, Andrew; Dai, Yongjiu; Yang, Chi; Chen, Zhuoqi; Li, Tao; Wang, Zhonglei

2014-01-01

Partial thin-plate smoothing spline model is used to construct the trend surface.Correction of the spline estimated trend surface is often necessary in practice.Cressman weight is modified and applied in residual correction.The modified Cressman weight performs better than Cressman weight.A method for estimating the error covariance matrix of gridded field is provided.

TU-C-BRE-05: Clinical Implications of AAA Commissioning Errors and Ability of Common Commissioning ' Credentialing Procedures to Detect Them

DOE Office of Scientific and Technical Information (OSTI.GOV)

McVicker, A; Oldham, M; Yin, F

2014-06-15

Purpose: To test the ability of the TG-119 commissioning process and RPC credentialing to detect errors in the commissioning process for a commercial Treatment Planning System (TPS). Methods: We introduced commissioning errors into the commissioning process for the Anisotropic Analytical Algorithm (AAA) within the Eclipse TPS. We included errors in Dosimetric Leaf Gap (DLG), electron contamination, flattening filter material, and beam profile measurement with an inappropriately large farmer chamber (simulated using sliding window smoothing of profiles). We then evaluated the clinical impact of these errors on clinical intensity modulated radiation therapy (IMRT) plans (head and neck, low and intermediate riskmore » prostate, mesothelioma, and scalp) by looking at PTV D99, and mean and max OAR dose. Finally, for errors with substantial clinical impact we determined sensitivity of the RPC IMRT film analysis at the midpoint between PTV and OAR using a 4mm distance to agreement metric, and of a 7% TLD dose comparison. We also determined sensitivity of the 3 dose planes of the TG-119 C-shape IMRT phantom using gamma criteria of 3% 3mm. Results: The largest clinical impact came from large changes in the DLG with a change of 1mm resulting in up to a 5% change in the primary PTV D99. This resulted in a discrepancy in the RPC TLDs in the PTVs and OARs of 7.1% and 13.6% respectively, which would have resulted in detection. While use of incorrect flattening filter caused only subtle errors (<1%) in clinical plans, the effect was most pronounced for the RPC TLDs in the OARs (>6%). Conclusion: The AAA commissioning process within the Eclipse TPS is surprisingly robust to user error. When errors do occur, the RPC and TG-119 commissioning credentialing criteria are effective at detecting them; however OAR TLDs are the most sensitive despite the RPC currently excluding them from analysis.« less

Disclosing harmful medical errors to patients: tackling three tough cases.

PubMed

Gallagher, Thomas H; Bell, Sigall K; Smith, Kelly M; Mello, Michelle M; McDonald, Timothy B

2009-09-01

A gap exists between recommendations to disclose errors to patients and current practice. This gap may reflect important, yet unanswered questions about implementing disclosure principles. We explore some of these unanswered questions by presenting three real cases that pose challenging disclosure dilemmas. The first case involves a pancreas transplant that failed due to the pancreas graft being discarded, an error that was not disclosed partly because the family did not ask clarifying questions. Relying on patient or family questions to determine the content of disclosure is problematic. We propose a standard of materiality that can help clinicians to decide what information to disclose. The second case involves a fatal diagnostic error that the patient's widower was unaware had happened. The error was not disclosed out of concern that disclosure would cause the widower more harm than good. This case highlights how institutions can overlook patients' and families' needs following errors and emphasizes that benevolent deception has little role in disclosure. Institutions should consider whether involving neutral third parties could make disclosures more patient centered. The third case presents an intraoperative cardiac arrest due to a large air embolism where uncertainty around the clinical event was high and complicated the disclosure. Uncertainty is common to many medical errors but should not deter open conversations with patients and families about what is and is not known about the event. Continued discussion within the medical profession about applying disclosure principles to real-world cases can help to better meet patients' and families' needs following medical errors.

Error Correction, Control Systems and Fuzzy Logic

NASA Technical Reports Server (NTRS)

Smith, Earl B.

2004-01-01

This paper will be a discussion on dealing with errors. While error correction and communication is important when dealing with spacecraft vehicles, the issue of control system design is also important. There will be certain commands that one wants a motion device to execute. An adequate control system will be necessary to make sure that the instruments and devices will receive the necessary commands. As it will be discussed later, the actual value will not always be equal to the intended or desired value. Hence, an adequate controller will be necessary so that the gap between the two values will be closed.

Application of Holt exponential smoothing and ARIMA method for data population in West Java

NASA Astrophysics Data System (ADS)

Supriatna, A.; Susanti, D.; Hertini, E.

2017-01-01

One method of time series that is often used to predict data that contains trend is Holt. Holt method using different parameters used in the original data which aims to smooth the trend value. In addition to Holt, ARIMA method can be used on a wide variety of data including data pattern containing a pattern trend. Data actual of population from 1998-2015 contains the trends so can be solved by Holt and ARIMA method to obtain the prediction value of some periods. The best method is measured by looking at the smallest MAPE and MAE error. The result using Holt method is 47.205.749 populations in 2016, 47.535.324 populations in 2017, and 48.041.672 populations in 2018, with MAPE error is 0,469744 and MAE error is 189.731. While the result using ARIMA method is 46.964.682 populations in 2016, 47.342.189 in 2017, and 47.899.696 in 2018, with MAPE error is 0,4380 and MAE is 176.626.

Smooth halos in the cosmic web

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaite, José, E-mail: jose.gaite@upm.es

Dark matter halos can be defined as smooth distributions of dark matter placed in a non-smooth cosmic web structure. This definition of halos demands a precise definition of smoothness and a characterization of the manner in which the transition from smooth halos to the cosmic web takes place. We introduce entropic measures of smoothness, related to measures of inequality previously used in economy and with the advantage of being connected with standard methods of multifractal analysis already used for characterizing the cosmic web structure in cold dark matter N-body simulations. These entropic measures provide us with a quantitative description ofmore » the transition from the small scales portrayed as a distribution of halos to the larger scales portrayed as a cosmic web and, therefore, allow us to assign definite sizes to halos. However, these ''smoothness sizes'' have no direct relation to the virial radii. Finally, we discuss the influence of N-body discreteness parameters on smoothness.« less

Simulations of the kinematic dynamo onset of spherical Couette flows with smooth and rough boundaries.

PubMed

Finke, K; Tilgner, A

2012-07-01

We study numerically the dynamo transition of an incompressible electrically conducting fluid filling the gap between two concentric spheres. In a first series of simulations, the fluid is driven by the rotation of a smooth inner sphere through no-slip boundary conditions, whereas the outer sphere is stationary. In a second series a volume force intended to simulate a rough surface drives the fluid next to the inner sphere within a layer of thickness one-tenth of the gap width. We investigate the effect of the boundary layer thickness on the dynamo threshold in the turbulent regime. The simulations show that the boundary forcing simulating the rough surface lowers the necessary rotation rate, which may help to improve spherical dynamo experiments.

Leiomodin and tropomodulin in smooth muscle

NASA Technical Reports Server (NTRS)

Conley, C. A.

2001-01-01

Evidence is accumulating to suggest that actin filament remodeling is critical for smooth muscle contraction, which implicates actin filament ends as important sites for regulation of contraction. Tropomodulin (Tmod) and smooth muscle leiomodin (SM-Lmod) have been found in many tissues containing smooth muscle by protein immunoblot and immunofluorescence microscopy. Both proteins cofractionate with tropomyosin in the Triton-insoluble cytoskeleton of rabbit stomach smooth muscle and are solubilized by high salt. SM-Lmod binds muscle tropomyosin, a biochemical activity characteristic of Tmod proteins. SM-Lmod staining is present along the length of actin filaments in rat intestinal smooth muscle, while Tmod stains in a punctate pattern distinct from that of actin filaments or the dense body marker alpha-actinin. After smooth muscle is hypercontracted by treatment with 10 mM Ca(2+), both SM-Lmod and Tmod are found near alpha-actinin at the periphery of actin-rich contraction bands. These data suggest that SM-Lmod is a novel component of the smooth muscle actin cytoskeleton and, furthermore, that the pointed ends of actin filaments in smooth muscle may be capped by Tmod in localized clusters.

Reverse engineering the gap gene network of Drosophila melanogaster.

PubMed

Perkins, Theodore J; Jaeger, Johannes; Reinitz, John; Glass, Leon

2006-05-01

A fundamental problem in functional genomics is to determine the structure and dynamics of genetic networks based on expression data. We describe a new strategy for solving this problem and apply it to recently published data on early Drosophila melanogaster development. Our method is orders of magnitude faster than current fitting methods and allows us to fit different types of rules for expressing regulatory relationships. Specifically, we use our approach to fit models using a smooth nonlinear formalism for modeling gene regulation (gene circuits) as well as models using logical rules based on activation and repression thresholds for transcription factors. Our technique also allows us to infer regulatory relationships de novo or to test network structures suggested by the literature. We fit a series of models to test several outstanding questions about gap gene regulation, including regulation of and by hunchback and the role of autoactivation. Based on our modeling results and validation against the experimental literature, we propose a revised network structure for the gap gene system. Interestingly, some relationships in standard textbook models of gap gene regulation appear to be unnecessary for or even inconsistent with the details of gap gene expression during wild-type development.

Aliased tidal errors in TOPEX/POSEIDON sea surface height data

NASA Technical Reports Server (NTRS)

Schlax, Michael G.; Chelton, Dudley B.

1994-01-01

Alias periods and wavelengths for the M(sub 2, S(sub 2), N(sub 2), K(sub 1), O(sub 1), and P(sub 1) tidal constituents are calculated for TOPEX/POSEIDON. Alias wavelenghts calculated in previous studies are shown to be in error, and a correct method is presented. With the exception of the K(sub 1) constituent, all of these tidal aliases for TOPEX/POSEIDON have periods shorter than 90 days and are likely to be confounded with long-period sea surface height signals associated with real ocean processes. In particular, the correspondence between the periods and wavelengths of the M(sub 2) alias and annual baroclinic Rossby waves that plagued Geosat sea surface height data is avoided. The potential for aliasing residual tidal errors in smoothed estimates of sea surface height is calculated for the six tidal constituents. The potential for aliasing the lunar tidal constituents M(sub 2), N(sub 2) and O(sub 1) fluctuates with latitude and is different for estimates made at the crossovers of ascending and descending ground tracks than for estimates at points midway between crossovers. The potential for aliasing the solar tidal constituents S(sub 2), K(sub 1) and P(sub 1) varies smoothly with latitude. S(sub 2) is strongly aliased for latitudes within 50 degress of the equator, while K(sub 1) and P(sub 1) are only weakly aliased in that range. A weighted least squares method for estimating and removing residual tidal errors from TOPEX/POSEIDON sea surface height data is presented. A clear understanding of the nature of aliased tidal error in TOPEX/POSEIDON data aids the unambiguous identification of real propagating sea surface height signals. Unequivocal evidence of annual period, westward propagating waves in the North Atlantic is presented.

7 CFR 51.636 - Smooth texture.

Code of Federal Regulations, 2010 CFR

2010-01-01

... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States...) Definitions § 51.636 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and...

7 CFR 51.698 - Smooth texture.

Code of Federal Regulations, 2010 CFR

2010-01-01

... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States... § 51.698 Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size...

Error reduction, patient safety and institutional ethics committees.

PubMed

Meaney, Mark E

2004-01-01

Institutional ethics committees remain largely absent from the literature on error reduction and patient safety. In this paper, the author endeavors to fill the gap. As noted in the Hastings Center's recent report, "Promoting Patient Safety," the occurrence of medical error involves complex web of multiple factors. Human misstep is certainly one such factor, but not the only one. This paper builds on the Hastings Center's report in arguing that institutional ethics committees ought to play an integral role in the transformation of a "culture of blame" to a "culture of safety" in healthcare delivery.

Mind the Gap: The Effect of Keyboard Key Gap and Pitch on Typing Speed, Accuracy, and Usability, Part 3.

PubMed

Madison, Heather; Pereira, Anna; Korshøj, Mette; Taylor, Laura; Barr, Alan; Rempel, David

2015-11-01

The aim of this study was to evaluate the effects of key gap (distance between edges of keys) on computer keyboards on typing speed, percentage error, preference, and usability. In Parts 1 and 2 of this series, a small key pitch (center-to-center distance between keys) was found to reduce productivity and usability, but the findings were confounded by gap. In this study, key gap was varied while holding key pitch constant. Participants (N = 25) typed on six keyboards, which differed in gap between keys (1, 3, or 5 mm) and pitch (16 or 17 mm; distance between centers of keys), while typing speed, accuracy, usability, and preference were measured. There was no statistical interaction between gap and pitch. Accuracy was better for keyboards with a gap of 5 mm compared to a 1-mm gap (p = .04). Net typing speed (p = .02), accuracy (p = .002), and most usability measures were better for keyboards with a pitch of 17 mm compared to a 16-mm pitch. The study findings support keyboard designs with a gap between keys of 5 mm over 1 mm and a key pitch of 17 mm over 16 mm. These findings may influence keyboard standards and design, especially the design of small keyboards used with portable devices, such as tablets and laptops. © 2015, Human Factors and Ergonomics Society.

7 CFR 51.768 - Smooth texture.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. “Thin” means that the skin thickness does not average more than 3/8 inch (9.5 mm), on a central...

7 CFR 51.768 - Smooth texture.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Smooth texture. Smooth texture means that the skin is thin and smooth for the variety and size of the fruit. “Thin” means that the skin thickness does not average more than 3/8 inch (9.5 mm), on a central...

Enhanced p122RhoGAP/DLC-1 Expression Can Be a Cause of Coronary Spasm

PubMed Central

Kinjo, Takahiko; Tanaka, Makoto; Osanai, Tomohiro; Shibutani, Shuji; Narita, Ikuyo; Tanno, Tomohiro; Nishizaki, Kimitaka; Ichikawa, Hiroaki; Kimura, Yoshihiro; Ishida, Yuji; Yokota, Takashi; Shimada, Michiko; Homma, Yoshimi; Tomita, Hirofumi; Okumura, Ken

2015-01-01

Background We previously showed that phospholipase C (PLC)-δ1 activity was enhanced by 3-fold in patients with coronary spastic angina (CSA). We also reported that p122Rho GTPase-activating protein/deleted in liver cancer-1 (p122RhoGAP/DLC-1) protein, which was discovered as a PLC-δ1 stimulator, was upregulated in CSA patients. We tested the hypothesis that p122RhoGAP/DLC-1 overexpression causes coronary spasm. Methods and Results We generated transgenic (TG) mice with vascular smooth muscle (VSM)-specific overexpression of p122RhoGAP/DLC-1. The gene and protein expressions of p122RhoGAP/DLC-1 were markedly increased in the aorta of homozygous TG mice. Stronger staining with anti-p122RhoGAP/DLC-1 in the coronary artery was found in TG than in WT mice. PLC activities in the plasma membrane fraction and the whole cell were enhanced by 1.43 and 2.38 times, respectively, in cultured aortic vascular smooth muscle cells from homozygous TG compared with those from WT mice. Immediately after ergometrine injection, ST-segment elevation was observed in 1 of 7 WT (14%), 6 of 7 heterozygous TG (84%), and 7 of 7 homozygous TG mice (100%) (p<0.05, WT versus TGs). In the isolated Langendorff hearts, coronary perfusion pressure was increased after ergometrine in TG, but not in WT mice, despite of the similar response to prostaglandin F2α between TG and WT mice (n = 5). Focal narrowing of the coronary artery after ergometrine was documented only in TG mice. Conclusions VSM-specific overexpression of p122RhoGAP/DLC-1 enhanced coronary vasomotility after ergometrine injection in mice, which is relevant to human CSA. PMID:26624289

Multiscale measurement error models for aggregated small area health data.

PubMed

Aregay, Mehreteab; Lawson, Andrew B; Faes, Christel; Kirby, Russell S; Carroll, Rachel; Watjou, Kevin

2016-08-01

Spatial data are often aggregated from a finer (smaller) to a coarser (larger) geographical level. The process of data aggregation induces a scaling effect which smoothes the variation in the data. To address the scaling problem, multiscale models that link the convolution models at different scale levels via the shared random effect have been proposed. One of the main goals in aggregated health data is to investigate the relationship between predictors and an outcome at different geographical levels. In this paper, we extend multiscale models to examine whether a predictor effect at a finer level hold true at a coarser level. To adjust for predictor uncertainty due to aggregation, we applied measurement error models in the framework of multiscale approach. To assess the benefit of using multiscale measurement error models, we compare the performance of multiscale models with and without measurement error in both real and simulated data. We found that ignoring the measurement error in multiscale models underestimates the regression coefficient, while it overestimates the variance of the spatially structured random effect. On the other hand, accounting for the measurement error in multiscale models provides a better model fit and unbiased parameter estimates. © The Author(s) 2016.

Comparison of smoothing methods for the development of a smoothed seismicity model for Alaska and the implications for seismic hazard

NASA Astrophysics Data System (ADS)

Moschetti, M. P.; Mueller, C. S.; Boyd, O. S.; Petersen, M. D.

2013-12-01

In anticipation of the update of the Alaska seismic hazard maps (ASHMs) by the U. S. Geological Survey, we report progress on the comparison of smoothed seismicity models developed using fixed and adaptive smoothing algorithms, and investigate the sensitivity of seismic hazard to the models. While fault-based sources, such as those for great earthquakes in the Alaska-Aleutian subduction zone and for the ~10 shallow crustal faults within Alaska, dominate the seismic hazard estimates for locations near to the sources, smoothed seismicity rates make important contributions to seismic hazard away from fault-based sources and where knowledge of recurrence and magnitude is not sufficient for use in hazard studies. Recent developments in adaptive smoothing methods and statistical tests for evaluating and comparing rate models prompt us to investigate the appropriateness of adaptive smoothing for the ASHMs. We develop smoothed seismicity models for Alaska using fixed and adaptive smoothing methods and compare the resulting models by calculating and evaluating the joint likelihood test. We use the earthquake catalog, and associated completeness levels, developed for the 2007 ASHM to produce fixed-bandwidth-smoothed models with smoothing distances varying from 10 to 100 km and adaptively smoothed models. Adaptive smoothing follows the method of Helmstetter et al. and defines a unique smoothing distance for each earthquake epicenter from the distance to the nth nearest neighbor. The consequence of the adaptive smoothing methods is to reduce smoothing distances, causing locally increased seismicity rates, where seismicity rates are high and to increase smoothing distances where seismicity is sparse. We follow guidance from previous studies to optimize the neighbor number (n-value) by comparing model likelihood values, which estimate the likelihood that the observed earthquake epicenters from the recent catalog are derived from the smoothed rate models. We compare likelihood

Comparison of smoothing methods for the development of a smoothed seismicity model for Alaska and the implications for seismic hazard

USGS Publications Warehouse

Moschetti, Morgan P.; Mueller, Charles S.; Boyd, Oliver S.; Petersen, Mark D.

2014-01-01

In anticipation of the update of the Alaska seismic hazard maps (ASHMs) by the U. S. Geological Survey, we report progress on the comparison of smoothed seismicity models developed using fixed and adaptive smoothing algorithms, and investigate the sensitivity of seismic hazard to the models. While fault-based sources, such as those for great earthquakes in the Alaska-Aleutian subduction zone and for the ~10 shallow crustal faults within Alaska, dominate the seismic hazard estimates for locations near to the sources, smoothed seismicity rates make important contributions to seismic hazard away from fault-based sources and where knowledge of recurrence and magnitude is not sufficient for use in hazard studies. Recent developments in adaptive smoothing methods and statistical tests for evaluating and comparing rate models prompt us to investigate the appropriateness of adaptive smoothing for the ASHMs. We develop smoothed seismicity models for Alaska using fixed and adaptive smoothing methods and compare the resulting models by calculating and evaluating the joint likelihood test. We use the earthquake catalog, and associated completeness levels, developed for the 2007 ASHM to produce fixed-bandwidth-smoothed models with smoothing distances varying from 10 to 100 km and adaptively smoothed models. Adaptive smoothing follows the method of Helmstetter et al. and defines a unique smoothing distance for each earthquake epicenter from the distance to the nth nearest neighbor. The consequence of the adaptive smoothing methods is to reduce smoothing distances, causing locally increased seismicity rates, where seismicity rates are high and to increase smoothing distances where seismicity is sparse. We follow guidance from previous studies to optimize the neighbor number (n-value) by comparing model likelihood values, which estimate the likelihood that the observed earthquake epicenters from the recent catalog are derived from the smoothed rate models. We compare likelihood

Method and apparatus for controlling electrode gap during vacuum consumable arc remelting

DOEpatents

Fisher, R.W.; Maroone, J.P.; Tipping, D.W.; Zanner, F.J.

During vacuum consumable arc remelting the electrode gap between a consumable electrode and a pool of molten metal is difficult to control. The present invention monitors drop shorts by detecting a decrease in the voltage between the consumable electrode and molten pool. The drop shorts and their associated voltage reductions occur as repetitive pulses which are closely correlated to the electrode gap. Thus, the method and apparatus of the present invention controls electrode gap based upon drop shorts detected from the monitored anode-cathode voltage. The number of drop shorts are accumulated, and each time the number of drop shorts reach a predetermined number, the average period between drop shorts is calculated from this predetermined number and the time in which this number is accumulated. This average drop short period is used in a drop short period electrode gap model which determines the actual electrode gap from the drop short. The actual electrode gap is then compared with a desired electrode gap which is selected to produce optimum operating conditions and the velocity of the consumable error is varied based upon the gap error. The consumable electrode is driven according to any prior art system at this velocity. In the preferred embodiment, a microprocessor system is utilized to perform the necessary calculations and further to monitor the duration of each drop short. If any drop short exceeds a preset duration period, the consumable electrode is rapidly retracted a predetermined distance to prevent bonding of the consumable electrode to the molten remelt.

Distortion Representation of Forecast Errors for Model Skill Assessment and Objective Analysis

NASA Technical Reports Server (NTRS)

Hoffman, Ross N.; Nehrkorn, Thomas; Grassotti, Christopher

1996-01-01

We study a novel characterization of errors for numerical weather predictions. In its simplest form we decompose the error into a part attributable to phase errors and a remainder. The phase error is represented in the same fashion as a velocity field and will be required to vary slowly and smoothly with position. A general distortion representation allows for the displacement and a bias correction of forecast anomalies. In brief, the distortion is determined by minimizing the objective function by varying the displacement and bias correction fields. In the present project we use a global or hemispheric domain, and spherical harmonics to represent these fields. In this project we are initially focusing on the assessment application, restricted to a realistic but univariate 2-dimensional situation. Specifically we study the forecast errors of the 500 hPa geopotential height field for forecasts of the short and medium range. The forecasts are those of the Goddard Earth Observing System data assimilation system. Results presented show that the methodology works, that a large part of the total error may be explained by a distortion limited to triangular truncation at wavenumber 10, and that the remaining residual error contains mostly small spatial scales.

The Dynamic Actin Cytoskeleton in Smooth Muscle.

PubMed

Tang, Dale D

2018-01-01

Smooth muscle contraction requires both myosin activation and actin cytoskeletal remodeling. Actin cytoskeletal reorganization facilitates smooth muscle contraction by promoting force transmission between the contractile unit and the extracellular matrix (ECM), and by enhancing intercellular mechanical transduction. Myosin may be viewed to serve as an "engine" for smooth muscle contraction whereas the actin cytoskeleton may function as a "transmission system" in smooth muscle. The actin cytoskeleton in smooth muscle also undergoes restructuring upon activation with growth factors or the ECM, which controls smooth muscle cell proliferation and migration. Abnormal smooth muscle contraction, cell proliferation, and motility contribute to the development of vascular and pulmonary diseases. A number of actin-regulatory proteins including protein kinases have been discovered to orchestrate actin dynamics in smooth muscle. In particular, Abelson tyrosine kinase (c-Abl) is an important molecule that controls actin dynamics, contraction, growth, and motility in smooth muscle. Moreover, c-Abl coordinates the regulation of blood pressure and contributes to the pathogenesis of airway hyperresponsiveness and vascular/airway remodeling in vivo. Thus, c-Abl may be a novel pharmacological target for the development of new therapy to treat smooth muscle diseases such as hypertension and asthma. © 2018 Elsevier Inc. All rights reserved.

Pavement Smoothness and Fuel Efficiency: An Analysis of the Economic Dimensions of the Missouri Smooth Road Initiative.

DOT National Transportation Integrated Search

2006-12-18

This study investigated the affect of pavement smoothness on fuel efficiency, specifically examining the miles per gallon in fuel savings for smooth versus rough pavement. The study found a 53% improvement in smoothness which resulted in over 2.4% im...

Smooth muscle sphincteroplasty in colostomy.

PubMed

Kostov, Daniel V; Temelkov, Temelko D; Dragnev, Nedyalko A; Kobakov, Georgi L; Ivanov, Krasimir D

2004-04-01

The present work elaborated on Schmidt's idea of an effective smooth muscle sphincteroplasty. The aim of the study was to analyze the effects on the patients with a lower quadrant colostomy constructed after abdominoperineal extirpation of a modified smooth muscle sphincteroplasty combined with colon irrigations. Seventy-two rectal cancer patients (39 men and 33 women, median age, 54.5 years) with smooth muscle sphincteroplasty and 20 controls with conventional colostomy using colon irrigations (11 men and 9 women, median age, 63.2 years) were examined. A modified smooth muscle wrap of the colostomy with a free graft of a 4-cm-long colon segment without mucosa was applied. In this precolostomy segment a high intraluminal pressure was achieved. The functional capacity and anatomic integrity of the transplanted smooth muscle graft were examined manometrically, electromyographically, and histomorphologically. The functional activity of the colostomy was assessed by periodic recording of the number of "spontaneous" and "directed" defecations.RESULTS. In the patients with smooth muscle sphincteroplasty, the basal intraluminal pressure of the precolostomy segment two years after operation measured 29.7 mmHg. After dilatation of the transplant, these pressures reached up to 43 mmHg ( P < 0.001). The weekly "spontaneous" stools were 3 to 5 times less frequent than in the controls ( P < 0.001). The modified smooth muscle sphincteroplasty offers operative-technical opportunities for increasing intraluminal pressure in the precolostomy colon segment. Its combination with colonic irrigations facilitates control of the evacuatory rhythm and "spontaneous" stools in colostomy patients, thus improving their quality of life.

Spin Contamination Error in Optimized Geometry of Singlet Carbene (1A1) by Broken-Symmetry Method

NASA Astrophysics Data System (ADS)

Kitagawa, Yasutaka; Saito, Toru; Nakanishi, Yasuyuki; Kataoka, Yusuke; Matsui, Toru; Kawakami, Takashi; Okumura, Mitsutaka; Yamaguchi, Kizashi

2009-10-01

Spin contamination errors of a broken-symmetry (BS) method in optimized structural parameters of the singlet methylene (1A1) molecule are quantitatively estimated for the Hartree-Fock (HF) method, post-HF methods (CID, CCD, MP2, MP3, MP4(SDQ)), and a hybrid DFT (B3LYP) method. For the purpose, the optimized geometry by the BS method is compared with that of an approximate spin projection (AP) method. The difference between the BS and the AP methods is about 10-20° in the HCH angle. In order to examine the basis set dependency of the spin contamination error, calculated results by STO-3G, 6-31G*, and 6-311++G** are compared. The error depends on the basis sets, but the tendencies of each method are classified into two types. Calculated energy splitting values between the triplet and the singlet states (ST gap) indicate that the contamination of the stable triplet state makes the BS singlet solution stable and the ST gap becomes small. The energy order of the spin contamination error in the ST gap is estimated to be 10-1 eV.

On the alleged collisional origin of the Kirkwood Gaps. [in asteroid belt

NASA Technical Reports Server (NTRS)

Heppenheimer, T. A.

1975-01-01

This paper examines two proposed mechanisms whereby asteroidal collisions and close approaches may have given rise to the Kirkwood Gaps. The first hypothesis is that asteroids in near-resonant orbits have markedly increased collision probabilities and so are preferentially destroyed, or suffer decay in population density, within the resonance zones. A simple order-of-magnitude analysis shows that this hypothesis is untenable since it leads to conclusions which are either unrealistic or not in accord with present understanding of asteroidal physics. The second hypothesis is the Brouwer-Jefferys theory that collisions would smooth an asteroidal distribution function, as a function of Jacobi constant, thus forming resonance gaps. This hypothesis is examined by direct numerical integration of 50 asteroid orbits near the 2:1 resonance, with collisions simulated by random variables. No tendency to form a gap was observed.

An optimized method to calculate error correction capability of tool influence function in frequency domain

NASA Astrophysics Data System (ADS)

Wang, Jia; Hou, Xi; Wan, Yongjian; Shi, Chunyan

2017-10-01

An optimized method to calculate error correction capability of tool influence function (TIF) in certain polishing conditions will be proposed based on smoothing spectral function. The basic mathematical model for this method will be established in theory. A set of polishing experimental data with rigid conformal tool is used to validate the optimized method. The calculated results can quantitatively indicate error correction capability of TIF for different spatial frequency errors in certain polishing conditions. The comparative analysis with previous method shows that the optimized method is simpler in form and can get the same accuracy results with less calculating time in contrast to previous method.

Presentation of growth velocities of rural Haitian children using smoothing spline techniques.

PubMed

Waternaux, C; Hebert, J R; Dawson, R; Berggren, G G

1987-01-01

The examination of monthly (or quarterly) increments in weight or length is important for assessing the nutritional and health status of children. Growth velocities are widely thought to be more important than actual weight or length measurements per se. However, there are no standards by which clinicians, researchers, or parents can gauge a child's growth. This paper describes a method for computing growth velocities (monthly increments) for physical growth measurements with substantial measurement error and irregular spacing over time. These features are characteristic of data collected in the field where conditions are less than ideal. The technique of smoothing by splines provides a powerful tool to deal with the variability and irregularity of the measurements. The technique consists of approximating the observed data by a smooth curve as a clinician might have drawn on the child's growth chart. Spline functions are particularly appropriate to describe bio-physical processes such as growth, for which no model can be postulated a priori. This paper describes how the technique was used for the analysis of a large data base collected on pre-school aged children in rural Haiti. The sex-specific length and weight velocities derived from the spline-smoothed data are presented as reference data for researchers and others interested in longitudinal growth of children in the Third World.

Nuclear fusion-independent smooth muscle differentiation of human adipose-derived stem cells induced by a smooth muscle environment.

PubMed

Zhang, Rong; Jack, Gregory S; Rao, Nagesh; Zuk, Patricia; Ignarro, Louis J; Wu, Benjamin; Rodríguez, Larissa V

2012-03-01

Human adipose-derived stem cells hASC have been isolated and were shown to have multilineage differentiation capacity. Although both plasticity and cell fusion have been suggested as mechanisms for cell differentiation in vivo, the effect of the local in vivo environment on the differentiation of adipose-derived stem cells has not been evaluated. We previously reported the in vitro capacity of smooth muscle differentiation of these cells. In this study, we evaluate the effect of an in vivo smooth muscle environment in the differentiation of hASC. We studied this by two experimental designs: (a) in vivo evaluation of smooth muscle differentiation of hASC injected into a smooth muscle environment and (b) in vitro evaluation of smooth muscle differentiation capacity of hASC exposed to bladder smooth muscle cells. Our results indicate a time-dependent differentiation of hASC into mature smooth muscle cells when these cells are injected into the smooth musculature of the urinary bladder. Similar findings were seen when the cells were cocultured in vitro with primary bladder smooth muscle cells. Chromosomal analysis demonstrated that microenvironment cues rather than nuclear fusion are responsible for this differentiation. We conclude that cell plasticity is present in hASCs, and their differentiation is accomplished in the absence of nuclear fusion. Copyright © 2011 AlphaMed Press.

Voltage and pace-capture mapping of linear ablation lesions overestimates chronic ablation gap size.

PubMed

O'Neill, Louisa; Harrison, James; Chubb, Henry; Whitaker, John; Mukherjee, Rahul K; Bloch, Lars Ølgaard; Andersen, Niels Peter; Dam, Høgni; Jensen, Henrik K; Niederer, Steven; Wright, Matthew; O'Neill, Mark; Williams, Steven E

2018-04-26

Conducting gaps in lesion sets are a major reason for failure of ablation procedures. Voltage mapping and pace-capture have been proposed for intra-procedural identification of gaps. We aimed to compare gap size measured acutely and chronically post-ablation to macroscopic gap size in a porcine model. Intercaval linear ablation was performed in eight Göttingen minipigs with a deliberate gap of ∼5 mm left in the ablation line. Gap size was measured by interpolating ablation contact force values between ablation tags and thresholding at a low force cut-off of 5 g. Bipolar voltage mapping and pace-capture mapping along the length of the line were performed immediately, and at 2 months, post-ablation. Animals were euthanized and gap sizes were measured macroscopically. Voltage thresholds to define scar were determined by receiver operating characteristic analysis as <0.56 mV (acutely) and <0.62 mV (chronically). Taking the macroscopic gap size as gold standard, error in gap measurements were determined for voltage, pace-capture, and ablation contact force maps. All modalities overestimated chronic gap size, by 1.4 ± 2.0 mm (ablation contact force map), 5.1 ± 3.4 mm (pace-capture), and 9.5 ± 3.8 mm (voltage mapping). Error on ablation contact force map gap measurements were significantly less than for voltage mapping (P = 0.003, Tukey's multiple comparisons test). Chronically, voltage mapping and pace-capture mapping overestimated macroscopic gap size by 11.9 ± 3.7 and 9.8 ± 3.5 mm, respectively. Bipolar voltage and pace-capture mapping overestimate the size of chronic gap formation in linear ablation lesions. The most accurate estimation of chronic gap size was achieved by analysis of catheter-myocardium contact force during ablation.

Quality Tetrahedral Mesh Smoothing via Boundary-Optimized Delaunay Triangulation

PubMed Central

Gao, Zhanheng; Yu, Zeyun; Holst, Michael

2012-01-01

Despite its great success in improving the quality of a tetrahedral mesh, the original optimal Delaunay triangulation (ODT) is designed to move only inner vertices and thus cannot handle input meshes containing “bad” triangles on boundaries. In the current work, we present an integrated approach called boundary-optimized Delaunay triangulation (B-ODT) to smooth (improve) a tetrahedral mesh. In our method, both inner and boundary vertices are repositioned by analytically minimizing the error between a paraboloid function and its piecewise linear interpolation over the neighborhood of each vertex. In addition to the guaranteed volume-preserving property, the proposed algorithm can be readily adapted to preserve sharp features in the original mesh. A number of experiments are included to demonstrate the performance of our method. PMID:23144522

Smooth conditional distribution function and quantiles under random censorship.

PubMed

Leconte, Eve; Poiraud-Casanova, Sandrine; Thomas-Agnan, Christine

2002-09-01

We consider a nonparametric random design regression model in which the response variable is possibly right censored. The aim of this paper is to estimate the conditional distribution function and the conditional alpha-quantile of the response variable. We restrict attention to the case where the response variable as well as the explanatory variable are unidimensional and continuous. We propose and discuss two classes of estimators which are smooth with respect to the response variable as well as to the covariate. Some simulations demonstrate that the new methods have better mean square error performances than the generalized Kaplan-Meier estimator introduced by Beran (1981) and considered in the literature by Dabrowska (1989, 1992) and Gonzalez-Manteiga and Cadarso-Suarez (1994).

Pavement smoothness indices : research brief.

DOT National Transportation Integrated Search

1998-08-01

Many in the asphalt industry believe that initial pavement smoothness directly relates to : pavement life. Public perception of smoothness is also important. Oregon is interested in : determining the appropriate method of measurement to quantify smoo...

GEOS-C altimeter attitude bias error correction. [gate-tracking radar

NASA Technical Reports Server (NTRS)

Marini, J. W.

1974-01-01

A pulse-limited split-gate-tracking radar altimeter was flown on Skylab and will be used aboard GEOS-C. If such an altimeter were to employ a hypothetical isotropic antenna, the altimeter output would be independent of spacecraft orientation. To reduce power requirements the gain of the altimeter antenna proposed is increased to the point where its beamwidth is only a few degrees. The gain of the antenna consequently varies somewhat over the pulse-limited illuminated region of the ocean below the altimeter, and the altimeter output varies with antenna orientation. The error introduced into the altimeter data is modeled empirically, but close agreements with the expected errors was not realized. The attitude error effects expected with the GEOS-C altimeter are modelled using a form suggested by an analytical derivation. The treatment is restricted to the case of a relatively smooth sea, where the height of the ocean waves are small relative to the spatial length (pulse duration times speed of light) of the transmitted pulse.

A variational technique for smoothing flight-test and accident data

NASA Technical Reports Server (NTRS)

Bach, R. E., Jr.

1980-01-01

The problem of determining aircraft motions along a trajectory is solved using a variational algorithm that generates unmeasured states and forcing functions, and estimates instrument bias and scale-factor errors. The problem is formulated as a nonlinear fixed-interval smoothing problem, and is solved as a sequence of linear two-point boundary value problems, using a sweep method. The algorithm has been implemented for use in flight-test and accident analysis. Aircraft motions are assumed to be governed by a six-degree-of-freedom kinematic model; forcing functions consist of body accelerations and winds, and the measurement model includes aerodynamic and radar data. Examples of the determination of aircraft motions from typical flight-test and accident data are presented.

Error disclosure: a new domain for safety culture assessment.

PubMed

Etchegaray, Jason M; Gallagher, Thomas H; Bell, Sigall K; Dunlap, Ben; Thomas, Eric J

2012-07-01

To (1) develop and test survey items that measure error disclosure culture, (2) examine relationships among error disclosure culture, teamwork culture and safety culture and (3) establish predictive validity for survey items measuring error disclosure culture. All clinical faculty from six health institutions (four medical schools, one cancer centre and one health science centre) in The University of Texas System were invited to anonymously complete an electronic survey containing questions about safety culture and error disclosure. The authors found two factors to measure error disclosure culture: one factor is focused on the general culture of error disclosure and the second factor is focused on trust. Both error disclosure culture factors were unique from safety culture and teamwork culture (correlations were less than r=0.85). Also, error disclosure general culture and error disclosure trust culture predicted intent to disclose a hypothetical error to a patient (r=0.25, p<0.001 and r=0.16, p<0.001, respectively) while teamwork and safety culture did not predict such an intent (r=0.09, p=NS and r=0.12, p=NS). Those who received prior error disclosure training reported significantly higher levels of error disclosure general culture (t=3.7, p<0.05) and error disclosure trust culture (t=2.9, p<0.05). The authors created and validated a new measure of error disclosure culture that predicts intent to disclose an error better than other measures of healthcare culture. This measure fills an existing gap in organisational assessments by assessing transparent communication after medical error, an important aspect of culture.

``Particle traps'' at planet gap edges in disks: effects of grain growth and fragmentation

NASA Astrophysics Data System (ADS)

Gonzalez, J.-F.; Laibe, G.; Maddison, S. T.; Pinte, C.; Ménard, F.

2014-12-01

We model the dust evolution in protoplanetary disks (PPD) with 3D, Smoothed Particle Hydrodynamics (SPH), two-phase (gas+dust) hydrodynamical simulations. The gas+dust dynamics, where aerodynamic drag leads to the vertical settling and radial migration of grains, is consistently treated. In a previous work, we characterized the spatial distribution of non-growing dust grains of different sizes in a disk containing a gap-opening planet and investigated the gap's detectability with ALMA. Here we take into account the effects of grain growth and fragmentation and study their impact on the distribution of solids in the disk. We show that rapid grain growth in the ``particle traps'' at the edges of planet gaps are strongly affected by fragmentation. We discuss the consequences for ALMA and NOEMA observations.

Binary-disk interaction. II. Gap-opening criteria for unequal-mass binaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Del Valle, Luciano; Escala, Andrés, E-mail: ldelvalleb@gmail.com

We study the interaction of an unequal-mass binary with an isothermal circumbinary disk, motivated by the theoretical and observational evidence that after a major merger of gas-rich galaxies, a massive gaseous disk with a supermassive black hole binary will be formed in the nuclear region. We focus on the gravitational torques that the binary exerts on the disk and how these torques can drive the formation of a gap in the disk. This exchange of angular momentum between the binary and the disk is mainly driven by the gravitational interaction between the binary and a strong nonaxisymmetric density perturbation thatmore » is produced in the disk, in response to the presence of the binary. Using smoothed particle hydrodynamics numerical simulations, we test two gap-opening criteria, one that assumes the geometry of the density perturbation is an ellipsoid/thick spiral and another that assumes a flat spiral geometry for the density perturbation. We find that the flat spiral gap-opening criterion successfully predicts which simulations will have a gap in the disk and which will not. We also study the limiting cases predicted by the gap-opening criteria. Since the viscosity in our simulations is considerably smaller than the expected value in the nuclear regions of gas-rich merging galaxies, we conclude that in such environments the formation of a circumbinary gap is unlikely.« less

Bridging the gap between high and low acceleration for planetary escape

NASA Astrophysics Data System (ADS)

Indrikis, Janis; Preble, Jeffrey C.

With the exception of the often time consuming analysis by numerical optimization, no single orbit transfer analysis technique exists that can be applied over a wide range of accelerations. Using the simple planetary escape (parabolic trajectory) mission some of the more common techniques are considered as the limiting bastions at the high and the extremely low acceleration regimes. The brachistochrone, the minimum time of flight path, is proposed as the technique to bridge the gap between the high and low acceleration regions, providing a smooth bridge over the entire acceleration spectrum. A smooth and continuous velocity requirement is established for the planetary escape mission. By using these results, it becomes possible to determine the effect of finite accelerations on mission performance and target propulsion and power system designs which are consistent with a desired mission objective.

Magnetorheological elastic super-smooth finishing for high-efficiency manufacturing of ultraviolet laser resistant optics

NASA Astrophysics Data System (ADS)

Shi, Feng; Shu, Yong; Dai, Yifan; Peng, Xiaoqiang; Li, Shengyi

2013-07-01

Based on the elastic-plastic deformation theory, status between abrasives and workpiece in magnetorheological finishing (MRF) process and the feasibility of elastic polishing are analyzed. The relationship among material removal mechanism and particle force, removal efficiency, and surface topography are revealed through a set of experiments. The chemical dominant elastic super-smooth polishing can be fulfilled by changing the components of magnetorheological (MR) fluid and optimizing polishing parameters. The MR elastic super-smooth finishing technology can be applied in polishing high-power laser-irradiated components with high efficiency, high accuracy, low damage, and high laser-induced damage threshold (LIDT). A 430×430×10 mm fused silica (FS) optic window is polished and surface error is improved from 538.241 nm [peak to valley (PV)], 96.376 nm (rms) to 76.372 nm (PV), 8.295 nm (rms) after 51.6 h rough polishing, 42.6 h fine polishing, and 54.6 h super-smooth polishing. A 50×50×10 mm sample is polished with exactly the same parameters. The roughness is improved from 1.793 nm [roughness average (Ra)] to 0.167 nm (Ra) and LIDT is improved from 9.77 to 19.2 J/cm2 after MRF elastic polishing.

Impact of a smoothness incentive.

DOT National Transportation Integrated Search

2006-01-01

Smoothness, the absence of bumps and dips in the riding surface of a pavement, improves the quality of the ride and is believed to prolong the life of the pavement. This research addressed the impact of potential pay adjustments for smoothness on mai...

Resolution of the Band Gap Prediction Problem for Materials Design

DOE PAGES

Crowley, Jason M.; Tahir-Kheli, Jamil; Goddard, William A.

2016-03-04

An important property with any new material is the band gap. Standard density functional theory methods grossly underestimate band gaps. This is known as the band gap problem. Here in this paper, we show that the hybrid B3PW91 density functional returns band gaps with a mean absolute deviation (MAD) from experiment of 0.22 eV over 64 insulators with gaps spanning a factor of 500 from 0.014 to 7 eV. The MAD is 0.28 eV over 70 compounds with gaps up to 14.2 eV, with a mean error of -0.03 eV. To benchmark the quality of the hybrid method, we comparedmore » the hybrid method to the rigorous GW many-body perturbation theory method. Surprisingly, the MAD for B3PW91 is about 1.5 times smaller than the MAD for GW. Furthermore, B3PW91 is 3-4 orders of magnitude faster computationally. Hence, B3PW91 is a practical tool for predicting band gaps of materials before they are synthesized and represents a solution to the band gap prediction problem.« less

Long-term care physical environments--effect on medication errors.

PubMed

Mahmood, Atiya; Chaudhury, Habib; Gaumont, Alana; Rust, Tiana

2012-01-01

Few studies examine physical environmental factors and their effects on staff health, effectiveness, work errors and job satisfaction. To address this gap, this study aims to examine environmental features and their role in medication and nursing errors in long-term care facilities. A mixed methodological strategy was used. Data were collected via focus groups, observing medication preparation and administration, and a nursing staff survey in four facilities. The paper reveals that, during the medication preparation phase, physical design, such as medication room layout, is a major source of potential errors. During medication administration, social environment is more likely to contribute to errors. Interruptions, noise and staff shortages were particular problems. The survey's relatively small sample size needs to be considered when interpreting the findings. Also, actual error data could not be included as existing records were incomplete. The study offers several relatively low-cost recommendations to help staff reduce medication errors. Physical environmental factors are important when addressing measures to reduce errors. The findings of this study underscore the fact that the physical environment's influence on the possibility of medication errors is often neglected. This study contributes to the scarce empirical literature examining the relationship between physical design and patient safety.

Effect of smoothing on robust chaos.

PubMed

Deshpande, Amogh; Chen, Qingfei; Wang, Yan; Lai, Ying-Cheng; Do, Younghae

2010-08-01

In piecewise-smooth dynamical systems, situations can arise where the asymptotic attractors of the system in an open parameter interval are all chaotic (e.g., no periodic windows). This is the phenomenon of robust chaos. Previous works have established that robust chaos can occur through the mechanism of border-collision bifurcation, where border is the phase-space region where discontinuities in the derivatives of the dynamical equations occur. We investigate the effect of smoothing on robust chaos and find that periodic windows can arise when a small amount of smoothness is present. We introduce a parameter of smoothing and find that the measure of the periodic windows in the parameter space scales linearly with the parameter, regardless of the details of the smoothing function. Numerical support and a heuristic theory are provided to establish the scaling relation. Experimental evidence of periodic windows in a supposedly piecewise linear dynamical system, which has been implemented as an electronic circuit, is also provided.

Does Menstruation Explain Gender Gaps in Work Absenteeism?

ERIC Educational Resources Information Center

Herrmann, Mariesa A.; Rockoff, Jonah E.

2012-01-01

Ichino and Moretti (2009) find that menstruation may contribute to gender gaps in absenteeism and earnings, based on evidence that absences of young female Italian bank employees follow a 28-day cycle. We find this evidence is not robust to the correction of coding errors or small changes in specification, and we find no evidence of increased…

Discrete square root smoothing.

NASA Technical Reports Server (NTRS)

Kaminski, P. G.; Bryson, A. E., Jr.

1972-01-01

The basic techniques applied in the square root least squares and square root filtering solutions are applied to the smoothing problem. Both conventional and square root solutions are obtained by computing the filtered solutions, then modifying the results to include the effect of all measurements. A comparison of computation requirements indicates that the square root information smoother (SRIS) is more efficient than conventional solutions in a large class of fixed interval smoothing problems.

A preliminary taxonomy of medical errors in family practice.

PubMed

Dovey, S M; Meyers, D S; Phillips, R L; Green, L A; Fryer, G E; Galliher, J M; Kappus, J; Grob, P

2002-09-01

To develop a preliminary taxonomy of primary care medical errors. Qualitative analysis to identify categories of error reported during a randomized controlled trial of computer and paper reporting methods. The National Network for Family Practice and Primary Care Research. Family physicians. Medical error category, context, and consequence. Forty two physicians made 344 reports: 284 (82.6%) arose from healthcare systems dysfunction; 46 (13.4%) were errors due to gaps in knowledge or skills; and 14 (4.1%) were reports of adverse events, not errors. The main subcategories were: administrative failure (102; 30.9% of errors), investigation failures (82; 24.8%), treatment delivery lapses (76; 23.0%), miscommunication (19; 5.8%), payment systems problems (4; 1.2%), error in the execution of a clinical task (19; 5.8%), wrong treatment decision (14; 4.2%), and wrong diagnosis (13; 3.9%). Most reports were of errors that were recognized and occurred in reporters' practices. Affected patients ranged in age from 8 months to 100 years, were of both sexes, and represented all major US ethnic groups. Almost half the reports were of events which had adverse consequences. Ten errors resulted in patients being admitted to hospital and one patient died. This medical error taxonomy, developed from self-reports of errors observed by family physicians during their routine clinical practice, emphasizes problems in healthcare processes and acknowledges medical errors arising from shortfalls in clinical knowledge and skills. Patient safety strategies with most effect in primary care settings need to be broader than the current focus on medication errors.

Mind the gap: The impact of missing data on the calculation of phytoplankton phenology metrics

NASA Astrophysics Data System (ADS)

Cole, Harriet; Henson, Stephanie; Martin, Adrian; Yool, Andrew

2012-08-01

Annual phytoplankton blooms are key events in marine ecosystems and interannual variability in bloom timing has important implications for carbon export and the marine food web. The degree of match or mismatch between the timing of phytoplankton and zooplankton annual cycles may impact larval survival with knock-on effects at higher trophic levels. Interannual variability in phytoplankton bloom timing may also be used to monitor changes in the pelagic ecosystem that are either naturally or anthropogenically forced. Seasonality metrics that use satellite ocean color data have been developed to quantify the timing of phenological events which allow for objective comparisons between different regions and over long periods of time. However, satellite data sets are subject to frequent gaps due to clouds and atmospheric aerosols, or persistent data gaps in winter due to low sun angle. Here we quantify the impact of these gaps on determining the start and peak timing of phytoplankton blooms. We use the NASA Ocean Biogeochemical Model that assimilates SeaWiFS data as a gap-free time series and derive an empirical relationship between the percentage of missing data and error in the phenology metric. Applied globally, we find that the majority of subpolar regions have typical errors of 30 days for the bloom initiation date and 15 days for the peak date. The errors introduced by intermittent data must be taken into account in phenological studies.

Mapping forest canopy gaps using air-photo interpretation and ground surveys

USGS Publications Warehouse

Fox, T.J.; Knutson, M.G.; Hines, R.K.

2000-01-01

Canopy gaps are important structural components of forested habitats for many wildlife species. Recent improvements in the spatial accuracy of geographic information system tools facilitate accurate mapping of small canopy features such as gaps. We compared canopy-gap maps generated using ground survey methods with those derived from air-photo interpretation. We found that maps created from high-resolution air photos were more accurate than those created from ground surveys. Errors of omission were 25.6% for the ground-survey method and 4.7% for the air-photo method. One variable of inter est in songbird research is the distance from nests to gap edges. Distances from real and simulated nests to gap edges were longer using the ground-survey maps versus the air-photo maps, indicating that gap omission could potentially bias the assessment of spatial relationships. If research or management goals require location and size of canopy gaps and specific information about vegetation structure, we recommend a 2-fold approach. First, canopy gaps can be located and the perimeters defined using 1:15,000-scale or larger aerial photographs and the methods we describe. Mapped gaps can then be field-surveyed to obtain detailed vegetation data.

Image segmentation on adaptive edge-preserving smoothing

NASA Astrophysics Data System (ADS)

He, Kun; Wang, Dan; Zheng, Xiuqing

2016-09-01

Nowadays, typical active contour models are widely applied in image segmentation. However, they perform badly on real images with inhomogeneous subregions. In order to overcome the drawback, this paper proposes an edge-preserving smoothing image segmentation algorithm. At first, this paper analyzes the edge-preserving smoothing conditions for image segmentation and constructs an edge-preserving smoothing model inspired by total variation. The proposed model has the ability to smooth inhomogeneous subregions and preserve edges. Then, a kind of clustering algorithm, which reasonably trades off edge-preserving and subregion-smoothing according to the local information, is employed to learn the edge-preserving parameter adaptively. At last, according to the confidence level of segmentation subregions, this paper constructs a smoothing convergence condition to avoid oversmoothing. Experiments indicate that the proposed algorithm has superior performance in precision, recall, and F-measure compared with other segmentation algorithms, and it is insensitive to noise and inhomogeneous-regions.

Smoothly deformed light

NASA Technical Reports Server (NTRS)

Stenholm, Stig

1993-01-01

A single mode cavity is deformed smoothly to change its electromagnetic eigenfrequency. The system is modeled as a simple harmonic oscillator with a varying period. The Wigner function of the problem is obtained exactly by starting with a squeezed initial state. The result is evaluated for a linear change of the cavity length. The approach to the adiabatic limit is investigated. The maximum squeezing is found to occur for smooth change lasting only a fraction of the oscillational period. However, only a factor of two improvement over the adiabatic result proves to be possible. The sudden limit cannot be investigated meaningfully within the model.

Ceramic coatings on smooth surfaces

NASA Technical Reports Server (NTRS)

Miller, R. A. (Inventor); Brindley, W. J. (Inventor); Rouge, C. J. (Inventor)

1991-01-01

A metallic coating is plasma sprayed onto a smooth surface of a metal alloy substitute or on a bond coating. An initial thin ceramic layer is low pressure sprayed onto the smooth surface of the substrate or bond coating. Another ceramic layer is atmospheric plasma sprayed onto the initial ceramic layer.

Numerical and Experimental Investigation of Cavitating Characteristics in Centrifugal Pump with Gap Impeller

NASA Astrophysics Data System (ADS)

Zhu, Bing; Chen, Hongxun; Wei, Qun

2014-06-01

This paper is to study the cavitating characteristics in a low specific speed centrifugal pump with gap structure impeller experimentally and numerically. A scalable DES numerical method is proposed and developed by introducing the von Karman scale instead of the local grid scale, which can switch at the RANS and LES region interface smoothly and reasonably. The SDES method can detect and grasp unsteady scale flow structures, which were proved by the flow around a triangular prism and the cavitation flow in a centrifugal pump. Through numerical and experimental research, it's shown that the simulated results match qualitatively with tested cavitation performances and visualization patterns, and we can conclude that the gap structure impeller has a superior feature of cavitation suppression. Its mechanism may be the guiding flow feature of the small vice blade and the pressure auto-balance effect of the gap tunnel.

Sequential Least-Squares Using Orthogonal Transformations. [spacecraft communication/spacecraft tracking-data smoothing

NASA Technical Reports Server (NTRS)

Bierman, G. J.

1975-01-01

Square root information estimation, starting from its beginnings in least-squares parameter estimation, is considered. Special attention is devoted to discussions of sensitivity and perturbation matrices, computed solutions and their formal statistics, consider-parameters and consider-covariances, and the effects of a priori statistics. The constant-parameter model is extended to include time-varying parameters and process noise, and the error analysis capabilities are generalized. Efficient and elegant smoothing results are obtained as easy consequences of the filter formulation. The value of the techniques is demonstrated by the navigation results that were obtained for the Mariner Venus-Mercury (Mariner 10) multiple-planetary space probe and for the Viking Mars space mission.

A SAS IML Macro for Loglinear Smoothing

ERIC Educational Resources Information Center

Moses, Tim; von Davier, Alina

2011-01-01

Polynomial loglinear models for one-, two-, and higher-way contingency tables have important applications to measurement and assessment. They are essentially regarded as a smoothing technique, which is commonly referred to as loglinear smoothing. A SAS IML (SAS Institute, 2002a) macro was created to implement loglinear smoothing according to…

Regeneration and Maintenance of Intestinal Smooth Muscle Phenotypes

NASA Astrophysics Data System (ADS)

Walthers, Christopher M.

Tissue engineering is an emerging field of biomedical engineering that involves growing artificial organs to replace those lost to disease or injury. Within tissue engineering, there is a demand for artificial smooth muscle to repair tissues of the digestive tract, bladder, and vascular systems. Attempts to develop engineered smooth muscle tissues capable of contracting with sufficient strength to be clinically relevant have so far proven unsatisfactory. The goal of this research was to develop and sustain mature, contractile smooth muscle. Survival of implanted SMCs is critical to sustain the benefits of engineered smooth muscle. Survival of implanted smooth muscle cells was studied with layered, electrospun polycaprolactone implants with lasercut holes ranging from 0--25% porosity. It was found that greater angiogenesis was associated with increased survival of implanted cells, with a large increase at a threshold between 20% and 25% porosity. Heparan sulfate coatings improved the speed of blood vessel infiltration after 14 days of implantation. With these considerations, thicker engineered tissues may be possible. An improved smooth muscle tissue culture technique was utilized. Contracting smooth muscle was produced in culture by maintaining the native smooth muscle tissue organization, specifically by sustaining intact smooth muscle strips rather than dissociating tissue in to isolated smooth muscle cells. Isolated cells showed a decrease in maturity and contained fewer enteric neural and glial cells. Muscle strips also exhibited periodic contraction and regular fluctuation of intracellular calclium. The muscle strip maturity persisted after implantation in omentum for 14 days on polycaprolactone scaffolds. A low-cost, disposable bioreactor was developed to further improve maturity of cultured smooth muscle cells in an environment of controlled cyclical stress.The bioreactor consistently applied repeated mechanical strain with controllable inputs for strain

Local error estimates for discontinuous solutions of nonlinear hyperbolic equations

NASA Technical Reports Server (NTRS)

Tadmor, Eitan

1989-01-01

Let u(x,t) be the possibly discontinuous entropy solution of a nonlinear scalar conservation law with smooth initial data. Suppose u sub epsilon(x,t) is the solution of an approximate viscosity regularization, where epsilon greater than 0 is the small viscosity amplitude. It is shown that by post-processing the small viscosity approximation u sub epsilon, pointwise values of u and its derivatives can be recovered with an error as close to epsilon as desired. The analysis relies on the adjoint problem of the forward error equation, which in this case amounts to a backward linear transport with discontinuous coefficients. The novelty of this approach is to use a (generalized) E-condition of the forward problem in order to deduce a W(exp 1,infinity) energy estimate for the discontinuous backward transport equation; this, in turn, leads one to an epsilon-uniform estimate on moments of the error u(sub epsilon) - u. This approach does not follow the characteristics and, therefore, applies mutatis mutandis to other approximate solutions such as E-difference schemes.

An earthquake rate forecast for Europe based on smoothed seismicity and smoothed fault contribution

NASA Astrophysics Data System (ADS)

Hiemer, Stefan; Woessner, Jochen; Basili, Roberto; Wiemer, Stefan

2013-04-01

The main objective of project SHARE (Seismic Hazard Harmonization in Europe) is to develop a community-based seismic hazard model for the Euro-Mediterranean region. The logic tree of earthquake rupture forecasts comprises several methodologies including smoothed seismicity approaches. Smoothed seismicity thus represents an alternative concept to express the degree of spatial stationarity of seismicity and provides results that are more objective, reproducible, and testable. Nonetheless, the smoothed-seismicity approach suffers from the common drawback of being generally based on earthquake catalogs alone, i.e. the wealth of knowledge from geology is completely ignored. We present a model that applies the kernel-smoothing method to both past earthquake locations and slip rates on mapped crustal faults and subductions. The result is mainly driven by the data, being independent of subjective delineation of seismic source zones. The core parts of our model are two distinct location probability densities: The first is computed by smoothing past seismicity (using variable kernel smoothing to account for varying data density). The second is obtained by smoothing fault moment rate contributions. The fault moment rates are calculated by summing the moment rate of each fault patch on a fully parameterized and discretized fault as available from the SHARE fault database. We assume that the regional frequency-magnitude distribution of the entire study area is well known and estimate the a- and b-value of a truncated Gutenberg-Richter magnitude distribution based on a maximum likelihood approach that considers the spatial and temporal completeness history of the seismic catalog. The two location probability densities are linearly weighted as a function of magnitude assuming that (1) the occurrence of past seismicity is a good proxy to forecast occurrence of future seismicity and (2) future large-magnitude events occur more likely in the vicinity of known faults. Consequently

The Higgs transverse momentum distribution at NNLL and its theoretical errors

DOE PAGES

Neill, Duff; Rothstein, Ira Z.; Vaidya, Varun

2015-12-15

In this letter, we present the NNLL-NNLO transverse momentum Higgs distribution arising from gluon fusion. In the regime p ⊥ << m h we include the resummation of the large logs at next to next-to leading order and then match on to the α 2 s fixed order result near p ⊥~m h. By utilizing the rapidity renormalization group (RRG) we are able to smoothly match between the resummed, small p ⊥ regime and the fixed order regime. We give a detailed discussion of the scale dependence of the result including an analysis of the rapidity scale dependence. Our centralmore » value differs from previous results, in the transition region as well as the tail, by an amount which is outside the error band. Lastly, this difference is due to the fact that the RRG profile allows us to smoothly turn off the resummation.« less

Computer programs for smoothing and scaling airfoil coordinates

NASA Technical Reports Server (NTRS)

Morgan, H. L., Jr.

1983-01-01

Detailed descriptions are given of the theoretical methods and associated computer codes of a program to smooth and a program to scale arbitrary airfoil coordinates. The smoothing program utilizes both least-squares polynomial and least-squares cubic spline techniques to smooth interatively the second derivatives of the y-axis airfoil coordinates with respect to a transformed x-axis system which unwraps the airfoil and stretches the nose and trailing-edge regions. The corresponding smooth airfoil coordinates are then determined by solving a tridiagonal matrix of simultaneous cubic-spline equations relating the y-axis coordinates and their corresponding second derivatives. A technique for computing the camber and thickness distribution of the smoothed airfoil is also discussed. The scaling program can then be used to scale the thickness distribution generated by the smoothing program to a specific maximum thickness which is then combined with the camber distribution to obtain the final scaled airfoil contour. Computer listings of the smoothing and scaling programs are included.

A Starshade Petal Error Budget for Exo-Earth Detection and Characterization

NASA Technical Reports Server (NTRS)

Shaklan, Stuart B.; Marchen, Luis; Lisman, P. Douglas; Cady, Eric; Martin, Stefan; Thomson, Mark; Dumont, Philip; Kasdin, N. Jeremy

2011-01-01

We present a starshade error budget with engineering requirements that are well within the current manufacturing and metrology capabilities. The error budget is based on an observational scenario in which the starshade spins about its axis on timescales short relative to the zodi-limited integration time, typically several hours. The scatter from localized petal errors is smoothed into annuli around the center of the image plane, resulting in a large reduction in the background flux variation while reducing thermal gradients caused by structural shadowing. Having identified the performance sensitivity to petal shape errors with spatial periods of 3-4 cycles/petal as the most challenging aspect of the design, we have adopted and modeled a manufacturing approach that mitigates these perturbations with 1-meter-long precision edge segments positioned using commercial metrology that readily meets assembly requirements. We have performed detailed thermal modeling and show that the expected thermal deformations are well within the requirements as well. We compare the requirements for four cases: a 32 meter diameter starshade with a 1.5 meter telescope, analyzed at 75 and 90 milliarcseconds, and a 40 meter diameter starshade with a 4 meter telescope, analyzed at 60 and 75 milliarcseconds.

A preliminary taxonomy of medical errors in family practice

PubMed Central

Dovey, S; Meyers, D; Phillips, R; Green, L; Fryer, G; Galliher, J; Kappus, J; Grob, P

2002-01-01

Objective: To develop a preliminary taxonomy of primary care medical errors. Design: Qualitative analysis to identify categories of error reported during a randomized controlled trial of computer and paper reporting methods. Setting: The National Network for Family Practice and Primary Care Research. Participants: Family physicians. Main outcome measures: Medical error category, context, and consequence. Results: Forty two physicians made 344 reports: 284 (82.6%) arose from healthcare systems dysfunction; 46 (13.4%) were errors due to gaps in knowledge or skills; and 14 (4.1%) were reports of adverse events, not errors. The main subcategories were: administrative failures (102; 30.9% of errors), investigation failures (82; 24.8%), treatment delivery lapses (76; 23.0%), miscommunication (19; 5.8%), payment systems problems (4; 1.2%), error in the execution of a clinical task (19; 5.8%), wrong treatment decision (14; 4.2%), and wrong diagnosis (13; 3.9%). Most reports were of errors that were recognized and occurred in reporters' practices. Affected patients ranged in age from 8 months to 100 years, were of both sexes, and represented all major US ethnic groups. Almost half the reports were of events which had adverse consequences. Ten errors resulted in patients being admitted to hospital and one patient died. Conclusions: This medical error taxonomy, developed from self-reports of errors observed by family physicians during their routine clinical practice, emphasizes problems in healthcare processes and acknowledges medical errors arising from shortfalls in clinical knowledge and skills. Patient safety strategies with most effect in primary care settings need to be broader than the current focus on medication errors. PMID:12486987

Smooth Pursuit Eye Movement of Monkeys Naive to Laboratory Setups With Pictures and Artificial Stimuli.

PubMed

Botschko, Yehudit; Yarkoni, Merav; Joshua, Mati

2018-01-01

When animal behavior is studied in a laboratory environment, the animals are often extensively trained to shape their behavior. A crucial question is whether the behavior observed after training is part of the natural repertoire of the animal or represents an outlier in the animal's natural capabilities. This can be investigated by assessing the extent to which the target behavior is manifested during the initial stages of training and the time course of learning. We explored this issue by examining smooth pursuit eye movements in monkeys naïve to smooth pursuit tasks. We recorded the eye movements of monkeys from the 1st days of training on a step-ramp paradigm. We used bright spots, monkey pictures and scrambled versions of the pictures as moving targets. We found that during the initial stages of training, the pursuit initiation was largest for the monkey pictures and in some direction conditions close to target velocity. When the pursuit initiation was large, the monkeys mostly continued to track the target with smooth pursuit movements while correcting for displacement errors with small saccades. Two weeks of training increased the pursuit eye velocity in all stimulus conditions, whereas further extensive training enhanced pursuit slightly more. The training decreased the coefficient of variation of the eye velocity. Anisotropies that grade pursuit across directions were observed from the 1st day of training and mostly persisted across training. Thus, smooth pursuit in the step-ramp paradigm appears to be part of the natural repertoire of monkeys' behavior and training adjusts monkeys' natural predisposed behavior.

Random Walk Graph Laplacian-Based Smoothness Prior for Soft Decoding of JPEG Images.

PubMed

Liu, Xianming; Cheung, Gene; Wu, Xiaolin; Zhao, Debin

2017-02-01

Given the prevalence of joint photographic experts group (JPEG) compressed images, optimizing image reconstruction from the compressed format remains an important problem. Instead of simply reconstructing a pixel block from the centers of indexed discrete cosine transform (DCT) coefficient quantization bins (hard decoding), soft decoding reconstructs a block by selecting appropriate coefficient values within the indexed bins with the help of signal priors. The challenge thus lies in how to define suitable priors and apply them effectively. In this paper, we combine three image priors-Laplacian prior for DCT coefficients, sparsity prior, and graph-signal smoothness prior for image patches-to construct an efficient JPEG soft decoding algorithm. Specifically, we first use the Laplacian prior to compute a minimum mean square error initial solution for each code block. Next, we show that while the sparsity prior can reduce block artifacts, limiting the size of the overcomplete dictionary (to lower computation) would lead to poor recovery of high DCT frequencies. To alleviate this problem, we design a new graph-signal smoothness prior (desired signal has mainly low graph frequencies) based on the left eigenvectors of the random walk graph Laplacian matrix (LERaG). Compared with the previous graph-signal smoothness priors, LERaG has desirable image filtering properties with low computation overhead. We demonstrate how LERaG can facilitate recovery of high DCT frequencies of a piecewise smooth signal via an interpretation of low graph frequency components as relaxed solutions to normalized cut in spectral clustering. Finally, we construct a soft decoding algorithm using the three signal priors with appropriate prior weights. Experimental results show that our proposal outperforms the state-of-the-art soft decoding algorithms in both objective and subjective evaluations noticeably.

Kernel-Smoothing Estimation of Item Characteristic Functions for Continuous Personality Items: An Empirical Comparison with the Linear and the Continuous-Response Models

ERIC Educational Resources Information Center

Ferrando, Pere J.

2004-01-01

This study used kernel-smoothing procedures to estimate the item characteristic functions (ICFs) of a set of continuous personality items. The nonparametric ICFs were compared with the ICFs estimated (a) by the linear model and (b) by Samejima's continuous-response model. The study was based on a conditioned approach and used an error-in-variables…

Smooth quantile normalization.

PubMed

Hicks, Stephanie C; Okrah, Kwame; Paulson, Joseph N; Quackenbush, John; Irizarry, Rafael A; Bravo, Héctor Corrada

2018-04-01

Between-sample normalization is a critical step in genomic data analysis to remove systematic bias and unwanted technical variation in high-throughput data. Global normalization methods are based on the assumption that observed variability in global properties is due to technical reasons and are unrelated to the biology of interest. For example, some methods correct for differences in sequencing read counts by scaling features to have similar median values across samples, but these fail to reduce other forms of unwanted technical variation. Methods such as quantile normalization transform the statistical distributions across samples to be the same and assume global differences in the distribution are induced by only technical variation. However, it remains unclear how to proceed with normalization if these assumptions are violated, for example, if there are global differences in the statistical distributions between biological conditions or groups, and external information, such as negative or control features, is not available. Here, we introduce a generalization of quantile normalization, referred to as smooth quantile normalization (qsmooth), which is based on the assumption that the statistical distribution of each sample should be the same (or have the same distributional shape) within biological groups or conditions, but allowing that they may differ between groups. We illustrate the advantages of our method on several high-throughput datasets with global differences in distributions corresponding to different biological conditions. We also perform a Monte Carlo simulation study to illustrate the bias-variance tradeoff and root mean squared error of qsmooth compared to other global normalization methods. A software implementation is available from https://github.com/stephaniehicks/qsmooth.

Pavement Smoothness and Fuel Efficiency: An Analysis of the Economic Dimensions of the Missouri Smooth Roads Initiative.

DOT National Transportation Integrated Search

2006-11-01

Its widely accepted that smooth roads provide greater driver comfort and satisfaction, decreased vehicle maintenance costs, and better fuel economy. Now thanks to a recently completed study, the affect of pavement smoothness on fuel efficiency has...

Development of an Abort Gap Monitor for High-Energy Proton Rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beche, J.-F.; Byrd, J.; De Santis, S.

2004-11-10

The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the 'abort gap', and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitormore » based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider.« less

Development of an abort gap monitor for high-energy proton rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beche, Jean-Francois; Byrd, John; De Santis, Stefano

2004-05-03

The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the ''abort gap'' and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitormore » based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider« less

Smooth Sailing.

ERIC Educational Resources Information Center

Price, Beverley; Pincott, Maxine; Rebman, Ashley; Northcutt, Jen; Barsanti, Amy; Silkunas, Betty; Brighton, Susan K.; Reitz, David; Winkler, Maureen

1999-01-01

Presents discipline tips from several teachers to keep classrooms running smoothly all year. Some of the suggestions include the following: a bear-cave warning system, peer mediation, a motivational mystery, problem students acting as the teacher's assistant, a positive-behavior-reward chain, a hallway scavenger hunt (to ensure quiet passage…

What is the epidemiology of medication errors, error-related adverse events and risk factors for errors in adults managed in community care contexts? A systematic review of the international literature.

PubMed

Assiri, Ghadah Asaad; Shebl, Nada Atef; Mahmoud, Mansour Adam; Aloudah, Nouf; Grant, Elizabeth; Aljadhey, Hisham; Sheikh, Aziz

2018-05-05

To investigate the epidemiology of medication errors and error-related adverse events in adults in primary care, ambulatory care and patients' homes. Systematic review. Six international databases were searched for publications between 1 January 2006 and 31 December 2015. Two researchers independently extracted data from eligible studies and assessed the quality of these using established instruments. Synthesis of data was informed by an appreciation of the medicines' management process and the conceptual framework from the International Classification for Patient Safety. 60 studies met the inclusion criteria, of which 53 studies focused on medication errors, 3 on error-related adverse events and 4 on risk factors only. The prevalence of prescribing errors was reported in 46 studies: prevalence estimates ranged widely from 2% to 94%. Inappropriate prescribing was the most common type of error reported. Only one study reported the prevalence of monitoring errors, finding that incomplete therapeutic/safety laboratory-test monitoring occurred in 73% of patients. The incidence of preventable adverse drug events (ADEs) was estimated as 15/1000 person-years, the prevalence of drug-drug interaction-related adverse drug reactions as 7% and the prevalence of preventable ADE as 0.4%. A number of patient, healthcare professional and medication-related risk factors were identified, including the number of medications used by the patient, increased patient age, the number of comorbidities, use of anticoagulants, cases where more than one physician was involved in patients' care and care being provided by family physicians/general practitioners. A very wide variation in the medication error and error-related adverse events rates is reported in the studies, this reflecting heterogeneity in the populations studied, study designs employed and outcomes evaluated. This review has identified important limitations and discrepancies in the methodologies used and gaps in the literature

Smoothed particle hydrodynamics with GRAPE-1A

NASA Technical Reports Server (NTRS)

Umemura, Masayuki; Fukushige, Toshiyuki; Makino, Junichiro; Ebisuzaki, Toshikazu; Sugimoto, Daiichiro; Turner, Edwin L.; Loeb, Abraham

1993-01-01

We describe the implementation of a smoothed particle hydrodynamics (SPH) scheme using GRAPE-1A, a special-purpose processor used for gravitational N-body simulations. The GRAPE-1A calculates the gravitational force exerted on a particle from all other particles in a system, while simultaneously making a list of the nearest neighbors of the particle. It is found that GRAPE-1A accelerates SPH calculations by direct summation by about two orders of magnitudes for a ten thousand-particle simulation. The effective speed is 80 Mflops, which is about 30 percent of the peak speed of GRAPE-1A. Also, in order to investigate the accuracy of GRAPE-SPH, some test simulations were executed. We found that the force and position errors are smaller than those due to representing a fluid by a finite number of particles. The total energy and momentum were conserved within 0.2-0.4 percent and 2-5 x 10 exp -5, respectively, in simulations with several thousand particles. We conclude that GRAPE-SPH is quite effective and sufficiently accurate for self-gravitating hydrodynamics.

Measurement error in environmental epidemiology and the shape of exposure-response curves.

PubMed

Rhomberg, Lorenz R; Chandalia, Juhi K; Long, Christopher M; Goodman, Julie E

2011-09-01

Both classical and Berkson exposure measurement errors as encountered in environmental epidemiology data can result in biases in fitted exposure-response relationships that are large enough to affect the interpretation and use of the apparent exposure-response shapes in risk assessment applications. A variety of sources of potential measurement error exist in the process of estimating individual exposures to environmental contaminants, and the authors review the evaluation in the literature of the magnitudes and patterns of exposure measurement errors that prevail in actual practice. It is well known among statisticians that random errors in the values of independent variables (such as exposure in exposure-response curves) may tend to bias regression results. For increasing curves, this effect tends to flatten and apparently linearize what is in truth a steeper and perhaps more curvilinear or even threshold-bearing relationship. The degree of bias is tied to the magnitude of the measurement error in the independent variables. It has been shown that the degree of bias known to apply to actual studies is sufficient to produce a false linear result, and that although nonparametric smoothing and other error-mitigating techniques may assist in identifying a threshold, they do not guarantee detection of a threshold. The consequences of this could be great, as it could lead to a misallocation of resources towards regulations that do not offer any benefit to public health.

Analysis of Two Advanced Smoothing Algorithms.

DTIC Science & Technology

1985-09-01

59 B. METHODOLOGY . ......... ........... 60 6 C. TESTING AND RESULTS ---- LINEAR UNDERLYING FUNCTION...SMOOTHING ALGORITHMS ...... .................... 94 A. GENERAL ......... ....................... .. 94 B. METHODOLOGY ............................ .95 C...to define succinctly. 59 B. METHODOLOGY There is no established procedure to follow in testing the efficiency and effectiveness of a smoothing

Error suppression and correction for quantum annealing

NASA Astrophysics Data System (ADS)

Lidar, Daniel

While adiabatic quantum computing and quantum annealing enjoy a certain degree of inherent robustness against excitations and control errors, there is no escaping the need for error correction or suppression. In this talk I will give an overview of our work on the development of such error correction and suppression methods. We have experimentally tested one such method combining encoding, energy penalties and decoding, on a D-Wave Two processor, with encouraging results. Mean field theory shows that this can be explained in terms of a softening of the closing of the gap due to the energy penalty, resulting in protection against excitations that occur near the quantum critical point. Decoding recovers population from excited states and enhances the success probability of quantum annealing. Moreover, we have demonstrated that using repetition codes with increasing code distance can lower the effective temperature of the annealer. References: K.L. Pudenz, T. Albash, D.A. Lidar, ``Error corrected quantum annealing with hundreds of qubits'', Nature Commun. 5, 3243 (2014). K.L. Pudenz, T. Albash, D.A. Lidar, ``Quantum annealing correction for random Ising problems'', Phys. Rev. A. 91, 042302 (2015). S. Matsuura, H. Nishimori, T. Albash, D.A. Lidar, ``Mean Field Analysis of Quantum Annealing Correction''. arXiv:1510.07709. W. Vinci et al., in preparation.

Modal Correction Method For Dynamically Induced Errors In Wind-Tunnel Model Attitude Measurements

NASA Technical Reports Server (NTRS)

Buehrle, R. D.; Young, C. P., Jr.

1995-01-01

This paper describes a method for correcting the dynamically induced bias errors in wind tunnel model attitude measurements using measured modal properties of the model system. At NASA Langley Research Center, the predominant instrumentation used to measure model attitude is a servo-accelerometer device that senses the model attitude with respect to the local vertical. Under smooth wind tunnel operating conditions, this inertial device can measure the model attitude with an accuracy of 0.01 degree. During wind tunnel tests when the model is responding at high dynamic amplitudes, the inertial device also senses the centrifugal acceleration associated with model vibration. This centrifugal acceleration results in a bias error in the model attitude measurement. A study of the response of a cantilevered model system to a simulated dynamic environment shows significant bias error in the model attitude measurement can occur and is vibration mode and amplitude dependent. For each vibration mode contributing to the bias error, the error is estimated from the measured modal properties and tangential accelerations at the model attitude device. Linear superposition is used to combine the bias estimates for individual modes to determine the overall bias error as a function of time. The modal correction model predicts the bias error to a high degree of accuracy for the vibration modes characterized in the simulated dynamic environment.

Active controls for ride smoothing

NASA Technical Reports Server (NTRS)

Conner, D. W.; Thompson, G. O.

1976-01-01

Active controls technology offers great promise for significantly smoothing the ride, and thus improving public and air carrier acceptance, of certain types of transport aircraft. Recent findings which support this promise are presented in the following three pertinent areas: (1) Ride quality versus degree of traveler satisfaction; (2) significant findings from a feasibility study of a ride smoothing system; and (3) potential ride problems identified for several advanced transport concepts.

A new smooth robust control design for uncertain nonlinear systems with non-vanishing disturbances

NASA Astrophysics Data System (ADS)

Xian, Bin; Zhang, Yao

2016-06-01

In this paper, we consider the control problem for a general class of nonlinear system subjected to uncertain dynamics and non-varnishing disturbances. A smooth nonlinear control algorithm is presented to tackle these uncertainties and disturbances. The proposed control design employs the integral of a nonlinear sigmoid function to compensate the uncertain dynamics, and achieve a uniformly semi-global practical asymptotic stable tracking control of the system outputs. A novel Lyapunov-based stability analysis is employed to prove the convergence of the tracking errors and the stability of the closed-loop system. Numerical simulation results on a two-link robot manipulator are presented to illustrate the performance of the proposed control algorithm comparing with the layer-boundary sliding mode controller and the robust of integration of sign of error control design. Furthermore, real-time experiment results for the attitude control of a quadrotor helicopter are also included to confirm the effectiveness of the proposed algorithm.

Ridge Polynomial Neural Network with Error Feedback for Time Series Forecasting

PubMed Central

Ghazali, Rozaida; Herawan, Tutut

2016-01-01

Time series forecasting has gained much attention due to its many practical applications. Higher-order neural network with recurrent feedback is a powerful technique that has been used successfully for time series forecasting. It maintains fast learning and the ability to learn the dynamics of the time series over time. Network output feedback is the most common recurrent feedback for many recurrent neural network models. However, not much attention has been paid to the use of network error feedback instead of network output feedback. In this study, we propose a novel model, called Ridge Polynomial Neural Network with Error Feedback (RPNN-EF) that incorporates higher order terms, recurrence and error feedback. To evaluate the performance of RPNN-EF, we used four univariate time series with different forecasting horizons, namely star brightness, monthly smoothed sunspot numbers, daily Euro/Dollar exchange rate, and Mackey-Glass time-delay differential equation. We compared the forecasting performance of RPNN-EF with the ordinary Ridge Polynomial Neural Network (RPNN) and the Dynamic Ridge Polynomial Neural Network (DRPNN). Simulation results showed an average 23.34% improvement in Root Mean Square Error (RMSE) with respect to RPNN and an average 10.74% improvement with respect to DRPNN. That means that using network errors during training helps enhance the overall forecasting performance for the network. PMID:27959927

Ridge Polynomial Neural Network with Error Feedback for Time Series Forecasting.

PubMed

Waheeb, Waddah; Ghazali, Rozaida; Herawan, Tutut

2016-01-01

Time series forecasting has gained much attention due to its many practical applications. Higher-order neural network with recurrent feedback is a powerful technique that has been used successfully for time series forecasting. It maintains fast learning and the ability to learn the dynamics of the time series over time. Network output feedback is the most common recurrent feedback for many recurrent neural network models. However, not much attention has been paid to the use of network error feedback instead of network output feedback. In this study, we propose a novel model, called Ridge Polynomial Neural Network with Error Feedback (RPNN-EF) that incorporates higher order terms, recurrence and error feedback. To evaluate the performance of RPNN-EF, we used four univariate time series with different forecasting horizons, namely star brightness, monthly smoothed sunspot numbers, daily Euro/Dollar exchange rate, and Mackey-Glass time-delay differential equation. We compared the forecasting performance of RPNN-EF with the ordinary Ridge Polynomial Neural Network (RPNN) and the Dynamic Ridge Polynomial Neural Network (DRPNN). Simulation results showed an average 23.34% improvement in Root Mean Square Error (RMSE) with respect to RPNN and an average 10.74% improvement with respect to DRPNN. That means that using network errors during training helps enhance the overall forecasting performance for the network.

A vorticity transport model to restore spatial gaps in velocity data

NASA Astrophysics Data System (ADS)

Ameli, Siavash; Shadden, Shawn

2017-11-01

Often measurements of velocity data do not have full spatial coverage in the probed domain or near boundaries. These gaps can be due to missing measurements or masked regions of corrupted data. These gaps confound interpretation, and are problematic when the data is used to compute Lagrangian or trajectory-based analyses. Various techniques have been proposed to overcome coverage limitations in velocity data such as unweighted least square fitting, empirical orthogonal function analysis, variational interpolation as well as boundary modal analysis. In this talk, we present a vorticity transport PDE to reconstruct regions of missing velocity vectors. The transport model involves both nonlinear anisotropic diffusion and advection. This approach is shown to preserve the main features of the flow even in cases of large gaps, and the reconstructed regions are continuous up to second order. We illustrate results for high-frequency radar (HFR) measurements of the ocean surface currents as this is a common application of limited coverage. We demonstrate that the error of the method is on the same order of the error of the original velocity data. In addition, we have developed a web-based gateway for data restoration, and we will demonstrate a practical application using available data. This work is supported by the NSF Grant No. 1520825.

Neurophysiology and Neuroanatomy of Smooth Pursuit in Humans

ERIC Educational Resources Information Center

Lencer, Rebekka; Trillenberg, Peter

2008-01-01

Smooth pursuit eye movements enable us to focus our eyes on moving objects by utilizing well-established mechanisms of visual motion processing, sensorimotor transformation and cognition. Novel smooth pursuit tasks and quantitative measurement techniques can help unravel the different smooth pursuit components and complex neural systems involved…

Radial Basis Function Based Quadrature over Smooth Surfaces

DTIC Science & Technology

2016-03-24

Radial Basis Functions φ(r) Piecewise Smooth (Conditionally Positive Definite) MN Monomial |r|2m+1 TPS thin plate spline |r|2mln|r| Infinitely Smooth...smooth surfaces using polynomial interpolants, while [27] couples Thin - Plate Spline interpolation (see table 1) with Green’s integral formula [29

Optimizations for optical velocity measurements in narrow gaps

NASA Astrophysics Data System (ADS)

Schlüßler, Raimund; Blechschmidt, Christian; Czarske, Jürgen; Fischer, Andreas

2013-09-01

Measuring the flow velocity in small gaps or near a surface with a nonintrusive optical measurement technique is a challenging measurement task, as disturbing light reflections from the surface appear. However, these measurements are important, e.g., in order to understand and to design the leakage flow in the tip gap between the rotor blade end face and the housing of a turbomachine. Hence, methods to reduce the interfering light power and to correct measurement errors caused by it need to be developed and verified. Different alternatives of minimizing the interfering light power for optical flow measurements in small gaps are presented. By optimizing the beam shape of the applied illumination beam using a numerical diffraction simulation, the interfering light power is reduced by up to a factor of 100. In combination with a decrease of the reflection coefficient of the rotor blade surface, an additional reduction of the interfering light power below the used scattered light power is possible. Furthermore, a correction algorithm to decrease the measurement uncertainty of disturbed measurements is derived. These improvements enable optical three-dimensional three-component flow velocity measurements in submillimeter gaps or near a surface.

Crash testing difference-smoothing algorithm on a large sample of simulated light curves from TDC1

NASA Astrophysics Data System (ADS)

Rathna Kumar, S.

2017-09-01

In this work, we propose refinements to the difference-smoothing algorithm for the measurement of time delay from the light curves of the images of a gravitationally lensed quasar. The refinements mainly consist of a more pragmatic approach to choose the smoothing time-scale free parameter, generation of more realistic synthetic light curves for the estimation of time delay uncertainty and using a plot of normalized χ2 computed over a wide range of trial time delay values to assess the reliability of a measured time delay and also for identifying instances of catastrophic failure. We rigorously tested the difference-smoothing algorithm on a large sample of more than thousand pairs of simulated light curves having known true time delays between them from the two most difficult 'rungs' - rung3 and rung4 - of the first edition of Strong Lens Time Delay Challenge (TDC1) and found an inherent tendency of the algorithm to measure the magnitude of time delay to be higher than the true value of time delay. However, we find that this systematic bias is eliminated by applying a correction to each measured time delay according to the magnitude and sign of the systematic error inferred by applying the time delay estimator on synthetic light curves simulating the measured time delay. Following these refinements, the TDC performance metrics for the difference-smoothing algorithm are found to be competitive with those of the best performing submissions of TDC1 for both the tested 'rungs'. The MATLAB codes used in this work and the detailed results are made publicly available.

Catecholamines release mediators in the opossum oesophageal circular smooth muscle.

PubMed Central

Daniel, E E; Jager, L P; Jury, J

1987-01-01

1. Effects of catecholamines applied exogenously to the circular smooth muscle layer of the body of the oesophagus of the opossum (Didelphis marsupialis) were studied, simultaneously measuring changes in the membrane potential, the membrane conductance and the contractility of the muscle, using the double sucrose-gap technique. 2. Superfusion of the smooth muscle with Krebs solution at 27 degrees C containing dopamine (10(-6)-10(-4) M) dose-dependently caused a hyperpolarization of the smooth muscle cells and an increased membrane resistance followed after gradual repolarization by oscillations of the membrane potential, often accompanied by muscle action potentials. During the hyperpolarization, the tendency for the membrane potential to sag during prolonged application of hyperpolarizing currents was reduced and the 'off' depolarization following such currents was increased. This muscle did not develop active tension prior to treatment; it therefore did not relax during the hyperpolarizations, but contracted following the depolarized phase of oscillations. 3. The non-adrenergic, non-cholinergic nerve-mediated inhibitory junction potential (i.j.p.) showed a small reduction in amplitude during superfusion with dopamine, explicable as a result of the drug-induced hyperpolarization. The 'off' response following the i.j.p., decreased transiently when the membrane potential was hyperpolarized to its maximum value. Then it increased to values larger than control as the membrane repolarized. Vasoactive intestinal polypeptide (VIP, 10(-6) M) produced a similar response but hyperpolarizations were smaller. 4. Of the tested catecholamines, isoprenaline, phenylephrine, butylated hydroxytoluene-920 (BHT-920) and clonidine were ineffective whereas the potency order for other catecholamines was dopamine greater than noradrenaline greater than or equal to adrenaline greater than DOPA. The catecholamine-induced responses were not affected by alpha- or beta

Acquisition of Pragmatic Routines by Learners of L2 English: Investigating Common Errors and Sources of Pragmatic Fossilization

ERIC Educational Resources Information Center

Tajeddin, Zia; Alemi, Minoo; Pashmforoosh, Roya

2017-01-01

Unlike linguistic fossilization, pragmatic fossilization has received scant attention in fossilization research. To bridge this gap, the present study adopted a typical-error method of fossilization research to identify the most frequent errors in pragmatic routines committed by Persian-speaking learners of L2 English and explore the sources of…

Comprehensive comparison of gap filling techniques for eddy covariance net carbon fluxes

NASA Astrophysics Data System (ADS)

Moffat, A. M.; Papale, D.; Reichstein, M.; Hollinger, D. Y.; Richardson, A. D.; Barr, A. G.; Beckstein, C.; Braswell, B. H.; Churkina, G.; Desai, A. R.; Falge, E.; Gove, J. H.; Heimann, M.; Hui, D.; Jarvis, A. J.; Kattge, J.; Noormets, A.; Stauch, V. J.

2007-12-01

Review of fifteen techniques for estimating missing values of net ecosystem CO2 exchange (NEE) in eddy covariance time series and evaluation of their performance for different artificial gap scenarios based on a set of ten benchmark datasets from six forested sites in Europe. The goal of gap filling is the reproduction of the NEE time series and hence this present work focuses on estimating missing NEE values, not on editing or the removal of suspect values in these time series due to systematic errors in the measurements (e.g. nighttime flux, advection). The gap filling was examined by generating fifty secondary datasets with artificial gaps (ranging in length from single half-hours to twelve consecutive days) for each benchmark dataset and evaluating the performance with a variety of statistical metrics. The performance of the gap filling varied among sites and depended on the level of aggregation (native half- hourly time step versus daily), long gaps were more difficult to fill than short gaps, and differences among the techniques were more pronounced during the day than at night. The non-linear regression techniques (NLRs), the look-up table (LUT), marginal distribution sampling (MDS), and the semi-parametric model (SPM) generally showed good overall performance. The artificial neural network based techniques (ANNs) were generally, if only slightly, superior to the other techniques. The simple interpolation technique of mean diurnal variation (MDV) showed a moderate but consistent performance. Several sophisticated techniques, the dual unscented Kalman filter (UKF), the multiple imputation method (MIM), the terrestrial biosphere model (BETHY), but also one of the ANNs and one of the NLRs showed high biases which resulted in a low reliability of the annual sums, indicating that additional development might be needed. An uncertainty analysis comparing the estimated random error in the ten benchmark datasets with the artificial gap residuals suggested that the

Charon's Smooth Plains

NASA Astrophysics Data System (ADS)

Beyer, R. A.; Spencer, J. R.; Nimmo, F.; Beddingfield, C.; Grundy, W. M.; McKinnon, W. B.; Moore, J.; Robbins, S.; Runyon, K.; Schenk, P.; Singer, K.; Weaver, H.; Young, L. A.; Ennico, K.; Olkin, C.; Stern, S. A.; New Horizons Science Team

2018-06-01

We hypothesize that Charon's smooth plains result from its global extension that caused crustal blocks to founder. Then, a viscous cryoflow composed of ammonia-rich mantle material rose up, enveloped the sinking blocks, and produced the plains.

Smooth pursuit eye movements and schizophrenia: literature review.

PubMed

Franco, J G; de Pablo, J; Gaviria, A M; Sepúlveda, E; Vilella, E

2014-09-01

To review the scientific literature about the relationship between impairment on smooth pursuit eye movements and schizophrenia. Narrative review that includes historical articles, reports about basic and clinical investigation, systematic reviews, and meta-analysis on the topic. Up to 80% of schizophrenic patients have impairment of smooth pursuit eye movements. Despite the diversity of test protocols, 65% of patients and controls are correctly classified by their overall performance during this pursuit. The smooth pursuit eye movements depend on the ability to anticipate the target's velocity and the visual feedback, as well as on learning and attention. The neuroanatomy implicated in smooth pursuit overlaps to some extent with certain frontal cortex zones associated with some clinical and neuropsychological characteristics of the schizophrenia, therefore some specific components of smooth pursuit anomalies could serve as biomarkers of the disease. Due to their sedative effect, antipsychotics have a deleterious effect on smooth pursuit eye movements, thus these movements cannot be used to evaluate the efficacy of the currently available treatments. Standardized evaluation of smooth pursuit eye movements on schizophrenia will allow to use specific aspects of that pursuit as biomarkers for the study of its genetics, psychopathology, or neuropsychology. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

Stability of iterative procedures with errors for approximating common fixed points of a couple of q-contractive-like mappings in Banach spaces

NASA Astrophysics Data System (ADS)

Zeng, Lu-Chuan; Yao, Jen-Chih

2006-09-01

Recently, Agarwal, Cho, Li and Huang [R.P. Agarwal, Y.J. Cho, J. Li, N.J. Huang, Stability of iterative procedures with errors approximating common fixed points for a couple of quasi-contractive mappings in q-uniformly smooth Banach spaces, J. Math. Anal. Appl. 272 (2002) 435-447] introduced the new iterative procedures with errors for approximating the common fixed point of a couple of quasi-contractive mappings and showed the stability of these iterative procedures with errors in Banach spaces. In this paper, we introduce a new concept of a couple of q-contractive-like mappings (q>1) in a Banach space and apply these iterative procedures with errors for approximating the common fixed point of the couple of q-contractive-like mappings. The results established in this paper improve, extend and unify the corresponding ones of Agarwal, Cho, Li and Huang [R.P. Agarwal, Y.J. Cho, J. Li, N.J. Huang, Stability of iterative procedures with errors approximating common fixed points for a couple of quasi-contractive mappings in q-uniformly smooth Banach spaces, J. Math. Anal. Appl. 272 (2002) 435-447], Chidume [C.E. Chidume, Approximation of fixed points of quasi-contractive mappings in Lp spaces, Indian J. Pure Appl. Math. 22 (1991) 273-386], Chidume and Osilike [C.E. Chidume, M.O. Osilike, Fixed points iterations for quasi-contractive maps in uniformly smooth Banach spaces, Bull. Korean Math. Soc. 30 (1993) 201-212], Liu [Q.H. Liu, On Naimpally and Singh's open questions, J. Math. Anal. Appl. 124 (1987) 157-164; Q.H. Liu, A convergence theorem of the sequence of Ishikawa iterates for quasi-contractive mappings, J. Math. Anal. Appl. 146 (1990) 301-305], Osilike [M.O. Osilike, A stable iteration procedure for quasi-contractive maps, Indian J. Pure Appl. Math. 27 (1996) 25-34; M.O. Osilike, Stability of the Ishikawa iteration method for quasi-contractive maps, Indian J. Pure Appl. Math. 28 (1997) 1251-1265] and many others in the literature.

Bifurcation theory for finitely smooth planar autonomous differential systems

NASA Astrophysics Data System (ADS)

Han, Maoan; Sheng, Lijuan; Zhang, Xiang

2018-03-01

In this paper we establish bifurcation theory of limit cycles for planar Ck smooth autonomous differential systems, with k ∈ N. The key point is to study the smoothness of bifurcation functions which are basic and important tool on the study of Hopf bifurcation at a fine focus or a center, and of Poincaré bifurcation in a period annulus. We especially study the smoothness of the first order Melnikov function in degenerate Hopf bifurcation at an elementary center. As we know, the smoothness problem was solved for analytic and C∞ differential systems, but it was not tackled for finitely smooth differential systems. Here, we present their optimal regularity of these bifurcation functions and their asymptotic expressions in the finite smooth case.

Does a better model yield a better argument? An info-gap analysis

NASA Astrophysics Data System (ADS)

Ben-Haim, Yakov

2017-04-01

Theories, models and computations underlie reasoned argumentation in many areas. The possibility of error in these arguments, though of low probability, may be highly significant when the argument is used in predicting the probability of rare high-consequence events. This implies that the choice of a theory, model or computational method for predicting rare high-consequence events must account for the probability of error in these components. However, error may result from lack of knowledge or surprises of various sorts, and predicting the probability of error is highly uncertain. We show that the putatively best, most innovative and sophisticated argument may not actually have the lowest probability of error. Innovative arguments may entail greater uncertainty than more standard but less sophisticated methods, creating an innovation dilemma in formulating the argument. We employ info-gap decision theory to characterize and support the resolution of this problem and present several examples.

7 CFR 51.1162 - Fairly smooth texture.

Code of Federal Regulations, 2010 CFR

2010-01-01

... MARKETING ACT OF 1946 FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND... smooth texture. Fairly smooth texture means that the skin is fairly thin and not coarse for the variety...

Error-related brain activity and error awareness in an error classification paradigm.

PubMed

Di Gregorio, Francesco; Steinhauser, Marco; Maier, Martin E

2016-10-01

Error-related brain activity has been linked to error detection enabling adaptive behavioral adjustments. However, it is still unclear which role error awareness plays in this process. Here, we show that the error-related negativity (Ne/ERN), an event-related potential reflecting early error monitoring, is dissociable from the degree of error awareness. Participants responded to a target while ignoring two different incongruent distractors. After responding, they indicated whether they had committed an error, and if so, whether they had responded to one or to the other distractor. This error classification paradigm allowed distinguishing partially aware errors, (i.e., errors that were noticed but misclassified) and fully aware errors (i.e., errors that were correctly classified). The Ne/ERN was larger for partially aware errors than for fully aware errors. Whereas this speaks against the idea that the Ne/ERN foreshadows the degree of error awareness, it confirms the prediction of a computational model, which relates the Ne/ERN to post-response conflict. This model predicts that stronger distractor processing - a prerequisite of error classification in our paradigm - leads to lower post-response conflict and thus a smaller Ne/ERN. This implies that the relationship between Ne/ERN and error awareness depends on how error awareness is related to response conflict in a specific task. Our results further indicate that the Ne/ERN but not the degree of error awareness determines adaptive performance adjustments. Taken together, we conclude that the Ne/ERN is dissociable from error awareness and foreshadows adaptive performance adjustments. Our results suggest that the relationship between the Ne/ERN and error awareness is correlative and mediated by response conflict. Copyright © 2016 Elsevier Inc. All rights reserved.

Coherent errors in quantum error correction

NASA Astrophysics Data System (ADS)

Greenbaum, Daniel; Dutton, Zachary

Analysis of quantum error correcting (QEC) codes is typically done using a stochastic, Pauli channel error model for describing the noise on physical qubits. However, it was recently found that coherent errors (systematic rotations) on physical data qubits result in both physical and logical error rates that differ significantly from those predicted by a Pauli model. We present analytic results for the logical error as a function of concatenation level and code distance for coherent errors under the repetition code. For data-only coherent errors, we find that the logical error is partially coherent and therefore non-Pauli. However, the coherent part of the error is negligible after two or more concatenation levels or at fewer than ɛ - (d - 1) error correction cycles. Here ɛ << 1 is the rotation angle error per cycle for a single physical qubit and d is the code distance. These results support the validity of modeling coherent errors using a Pauli channel under some minimum requirements for code distance and/or concatenation. We discuss extensions to imperfect syndrome extraction and implications for general QEC.

Gender Wage Gap Accounting: The Role of Selection Bias.

PubMed

Bar, Michael; Kim, Seik; Leukhina, Oksana

2015-10-01

Mulligan and Rubinstein (2008) (MR) argued that changing selection of working females on unobservable characteristics, from negative in the 1970s to positive in the 1990s, accounted for nearly the entire closing of the gender wage gap. We argue that their female wage equation estimates are inconsistent. Correcting this error substantially weakens the role of the rising selection bias (39 % versus 78 %) and strengthens the contribution of declining discrimination (42 % versus 7 %). Our findings resonate better with related literature. We also explain why our finding of positive selection in the 1970s provides additional support for MR's main hypothesis that an exogenous rise in the market value of unobservable characteristics contributed to the closing of the gender gap.

Radar data smoothing filter study

NASA Technical Reports Server (NTRS)

White, J. V.

1984-01-01

The accuracy of the current Wallops Flight Facility (WFF) data smoothing techniques for a variety of radars and payloads is examined. Alternative data reduction techniques are given and recommendations are made for improving radar data processing at WFF. A data adaptive algorithm, based on Kalman filtering and smoothing techniques, is also developed for estimating payload trajectories above the atmosphere from noisy time varying radar data. This algorithm is tested and verified using radar tracking data from WFF.

Smooth solutions of the Navier-Stokes equations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pokhozhaev, S I

2014-02-28

We consider smooth solutions of the Cauchy problem for the Navier-Stokes equations on the scale of smooth functions which are periodic with respect to x∈R{sup 3}. We obtain existence theorems for global (with respect to t>0) and local solutions of the Cauchy problem. The statements of these depend on the smoothness and the norm of the initial vector function. Upper bounds for the behaviour of solutions in both classes, which depend on t, are also obtained. Bibliography: 10 titles.

Directionally solidified Al2O3/GAP eutectic ceramics by micro-pulling-down method

NASA Astrophysics Data System (ADS)

Cao, Xue; Su, Haijun; Guo, Fengwei; Tan, Xi; Cao, Lamei

2016-11-01

We reported a novel route to prepare directionally solidified (DS) Al2O3/GAP eutectic ceramics by micro-pulling-down (μ-PD) method. The eutectic crystallizations, microstructure characters and evolutions, and their mechanical properties were investigated in detail. The results showed that the Al2O3/GAP eutectic composites can be successfully fabricated through μ-PD method, possessed smooth surface, full density and large crystal size (the maximal size: φ90 mm × 20 mm). At the process of Diameter, the as-solidified Al2O3/GAP eutectic presented a combination of "Chinese script" and elongated colony microstructure with complex regular structure. Inside the colonies, the rod-type or lamellar-type eutectic microstructures with ultra-fine GAP surrounded by the Al2O3 matrix were observed. At an appropriate solidificational rate, the binary eutectic exhibited a typical DS irregular eutectic structure of "chinese script" consisting of interpenetrating network of α-Al2O3 and GAP phases without any other phases. Therefore, the interphase spacing was refined to 1-2 µm and the irregular microstructure led to an outstanding vickers hardness of 17.04 GPa and fracture toughness of 6.3 MPa × m1/2 at room temperature.

Context Specificity of Post-Error and Post-Conflict Cognitive Control Adjustments

PubMed Central

Forster, Sarah E.; Cho, Raymond Y.

2014-01-01

There has been accumulating evidence that cognitive control can be adaptively regulated by monitoring for processing conflict as an index of online control demands. However, it is not yet known whether top-down control mechanisms respond to processing conflict in a manner specific to the operative task context or confer a more generalized benefit. While previous studies have examined the taskset-specificity of conflict adaptation effects, yielding inconsistent results, control-related performance adjustments following errors have been largely overlooked. This gap in the literature underscores recent debate as to whether post-error performance represents a strategic, control-mediated mechanism or a nonstrategic consequence of attentional orienting. In the present study, evidence of generalized control following both high conflict correct trials and errors was explored in a task-switching paradigm. Conflict adaptation effects were not found to generalize across tasksets, despite a shared response set. In contrast, post-error slowing effects were found to extend to the inactive taskset and were predictive of enhanced post-error accuracy. In addition, post-error performance adjustments were found to persist for several trials and across multiple task switches, a finding inconsistent with attentional orienting accounts of post-error slowing. These findings indicate that error-related control adjustments confer a generalized performance benefit and suggest dissociable mechanisms of post-conflict and post-error control. PMID:24603900

Local band gap measurements by VEELS of thin film solar cells.

PubMed

Keller, Debora; Buecheler, Stephan; Reinhard, Patrick; Pianezzi, Fabian; Pohl, Darius; Surrey, Alexander; Rellinghaus, Bernd; Erni, Rolf; Tiwari, Ayodhya N

2014-08-01

This work presents a systematic study that evaluates the feasibility and reliability of local band gap measurements of Cu(In,Ga)Se2 thin films by valence electron energy-loss spectroscopy (VEELS). The compositional gradients across the Cu(In,Ga)Se2 layer cause variations in the band gap energy, which are experimentally determined using a monochromated scanning transmission electron microscope (STEM). The results reveal the expected band gap variation across the Cu(In,Ga)Se2 layer and therefore confirm the feasibility of local band gap measurements of Cu(In,Ga)Se2 by VEELS. The precision and accuracy of the results are discussed based on the analysis of individual error sources, which leads to the conclusion that the precision of our measurements is most limited by the acquisition reproducibility, if the signal-to-noise ratio of the spectrum is high enough. Furthermore, we simulate the impact of radiation losses on the measured band gap value and propose a thickness-dependent correction. In future work, localized band gap variations will be measured on a more localized length scale to investigate, e.g., the influence of chemical inhomogeneities and dopant accumulations at grain boundaries.

Saccades to remembered targets: the effects of smooth pursuit and illusory stimulus motion

NASA Technical Reports Server (NTRS)

Zivotofsky, A. Z.; Rottach, K. G.; Averbuch-Heller, L.; Kori, A. A.; Thomas, C. W.; Dell'Osso, L. F.; Leigh, R. J.

1996-01-01

1. Measurements were made in four normal human subjects of the accuracy of saccades to remembered locations of targets that were flashed on a 20 x 30 deg random dot display that was either stationary or moving horizontally and sinusoidally at +/-9 deg at 0.3 Hz. During the interval between the target flash and the memory-guided saccade, the "memory period" (1.4 s), subjects either fixated a stationary spot or pursued a spot moving vertically sinusoidally at +/-9 deg at 0.3 Hz. 2. When saccades were made toward the location of targets previously flashed on a stationary background as subjects fixated the stationary spot, median saccadic error was 0.93 deg horizontally and 1.1 deg vertically. These errors were greater than for saccades to visible targets, which had median values of 0.59 deg horizontally and 0.60 deg vertically. 3. When targets were flashed as subjects smoothly pursued a spot that moved vertically across the stationary background, median saccadic error was 1.1 deg horizontally and 1.2 deg vertically, thus being of similar accuracy to when targets were flashed during fixation. In addition, the vertical component of the memory-guided saccade was much more closely correlated with the "spatial error" than with the "retinal error"; this indicated that, when programming the saccade, the brain had taken into account eye movements that occurred during the memory period. 4. When saccades were made to targets flashed during attempted fixation of a stationary spot on a horizontally moving background, a condition that produces a weak Duncker-type illusion of horizontal movement of the primary target, median saccadic error increased horizontally to 3.2 deg but was 1.1 deg vertically. 5. When targets were flashed as subjects smoothly pursued a spot that moved vertically on the horizontally moving background, a condition that induces a strong illusion of diagonal target motion, median saccadic error was 4.0 deg horizontally and 1.5 deg vertically; thus the horizontal

Stereotype susceptibility narrows the gender gap in imagined self-rotation performance.

PubMed

Wraga, Maryjane; Duncan, Lauren; Jacobs, Emily C; Helt, Molly; Church, Jessica

2006-10-01

Three studies examined the impact of stereotype messages on men's and women's performance of a mental rotation task involving imagined self-rotations. Experiment 1 established baseline differences between men and women; women made 12% more errors than did men. Experiment 2 found that exposure to a positive stereotype message enhanced women's performance in comparison with that of another group of women who received neutral information. In Experiment 3, men who were exposed to the same stereotype message emphasizing a female advantage made more errors than did male controls, and the magnitude of error was similar to that for women from Experiment 1. The results suggest that the gender gap in mental rotation performance is partially caused by experiential factors, particularly those induced by sociocultural stereotypes.

Fixed interval smoothing with discrete measurements.

NASA Technical Reports Server (NTRS)

Bierman, G. J.

1972-01-01

Smoothing equations for a linear continuous dynamic system with linear discrete measurements, derived from the discrete results of Rauch, Tung, and Striebel (1965), (R-T-S), are used to extend, through recursive updating, the previously published results of Bryson and Frazier (1963), (B-F), and yield a modified Bryson and Frazier, (M-B-F), algorithm. A comparison of the (M-B-F) and (R-T-S) algorithms leads to the conclusion that the former is to be preferred because it entails less computation, less storage, and less instability. It is felt that the presented (M-B-F) smoothing algorithm is a practical mechanization and should be of value in smoothing discretely observed dynamic linear systems.

Object motion computation for the initiation of smooth pursuit eye movements in humans.

PubMed

Wallace, Julian M; Stone, Leland S; Masson, Guillaume S

2005-04-01

Pursuing an object with smooth eye movements requires an accurate estimate of its two-dimensional (2D) trajectory. This 2D motion computation requires that different local motion measurements are extracted and combined to recover the global object-motion direction and speed. Several combination rules have been proposed such as vector averaging (VA), intersection of constraints (IOC), or 2D feature tracking (2DFT). To examine this computation, we investigated the time course of smooth pursuit eye movements driven by simple objects of different shapes. For type II diamond (where the direction of true object motion is dramatically different from the vector average of the 1-dimensional edge motions, i.e., VA not equal IOC = 2DFT), the ocular tracking is initiated in the vector average direction. Over a period of less than 300 ms, the eye-tracking direction converges on the true object motion. The reduction of the tracking error starts before the closing of the oculomotor loop. For type I diamonds (where the direction of true object motion is identical to the vector average direction, i.e., VA = IOC = 2DFT), there is no such bias. We quantified this effect by calculating the direction error between responses to types I and II and measuring its maximum value and time constant. At low contrast and high speeds, the initial bias in tracking direction is larger and takes longer to converge onto the actual object-motion direction. This effect is attenuated with the introduction of more 2D information to the extent that it was totally obliterated with a texture-filled type II diamond. These results suggest a flexible 2D computation for motion integration, which combines all available one-dimensional (edge) and 2D (feature) motion information to refine the estimate of object-motion direction over time.

Characterizing the impact of model error in hydrologic time series recovery inverse problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Scott K.; He, Jiachuan; Vesselinov, Velimir V.

Hydrologic models are commonly over-smoothed relative to reality, owing to computational limitations and to the difficulty of obtaining accurate high-resolution information. When used in an inversion context, such models may introduce systematic biases which cannot be encapsulated by an unbiased “observation noise” term of the type assumed by standard regularization theory and typical Bayesian formulations. Despite its importance, model error is difficult to encapsulate systematically and is often neglected. In this paper, model error is considered for an important class of inverse problems that includes interpretation of hydraulic transients and contaminant source history inference: reconstruction of a time series thatmore » has been convolved against a transfer function (i.e., impulse response) that is only approximately known. Using established harmonic theory along with two results established here regarding triangular Toeplitz matrices, upper and lower error bounds are derived for the effect of systematic model error on time series recovery for both well-determined and over-determined inverse problems. It is seen that use of additional measurement locations does not improve expected performance in the face of model error. A Monte Carlo study of a realistic hydraulic reconstruction problem is presented, and the lower error bound is seen informative about expected behavior. Finally, a possible diagnostic criterion for blind transfer function characterization is also uncovered.« less

Characterizing the impact of model error in hydrologic time series recovery inverse problems

DOE PAGES

Hansen, Scott K.; He, Jiachuan; Vesselinov, Velimir V.

2017-10-28

Hydrologic models are commonly over-smoothed relative to reality, owing to computational limitations and to the difficulty of obtaining accurate high-resolution information. When used in an inversion context, such models may introduce systematic biases which cannot be encapsulated by an unbiased “observation noise” term of the type assumed by standard regularization theory and typical Bayesian formulations. Despite its importance, model error is difficult to encapsulate systematically and is often neglected. In this paper, model error is considered for an important class of inverse problems that includes interpretation of hydraulic transients and contaminant source history inference: reconstruction of a time series thatmore » has been convolved against a transfer function (i.e., impulse response) that is only approximately known. Using established harmonic theory along with two results established here regarding triangular Toeplitz matrices, upper and lower error bounds are derived for the effect of systematic model error on time series recovery for both well-determined and over-determined inverse problems. It is seen that use of additional measurement locations does not improve expected performance in the face of model error. A Monte Carlo study of a realistic hydraulic reconstruction problem is presented, and the lower error bound is seen informative about expected behavior. Finally, a possible diagnostic criterion for blind transfer function characterization is also uncovered.« less

Combined Uncertainty and A-Posteriori Error Bound Estimates for General CFD Calculations: Theory and Software Implementation

NASA Technical Reports Server (NTRS)

Barth, Timothy J.

2014-01-01

This workshop presentation discusses the design and implementation of numerical methods for the quantification of statistical uncertainty, including a-posteriori error bounds, for output quantities computed using CFD methods. Hydrodynamic realizations often contain numerical error arising from finite-dimensional approximation (e.g. numerical methods using grids, basis functions, particles) and statistical uncertainty arising from incomplete information and/or statistical characterization of model parameters and random fields. The first task at hand is to derive formal error bounds for statistics given realizations containing finite-dimensional numerical error [1]. The error in computed output statistics contains contributions from both realization error and the error resulting from the calculation of statistics integrals using a numerical method. A second task is to devise computable a-posteriori error bounds by numerically approximating all terms arising in the error bound estimates. For the same reason that CFD calculations including error bounds but omitting uncertainty modeling are only of limited value, CFD calculations including uncertainty modeling but omitting error bounds are only of limited value. To gain maximum value from CFD calculations, a general software package for uncertainty quantification with quantified error bounds has been developed at NASA. The package provides implementations for a suite of numerical methods used in uncertainty quantification: Dense tensorization basis methods [3] and a subscale recovery variant [1] for non-smooth data, Sparse tensorization methods[2] utilizing node-nested hierarchies, Sampling methods[4] for high-dimensional random variable spaces.

Nonmuscle myosin is regulated during smooth muscle contraction.

PubMed

Yuen, Samantha L; Ogut, Ozgur; Brozovich, Frank V

2009-07-01

The participation of nonmuscle myosin in force maintenance is controversial. Furthermore, its regulation is difficult to examine in a cellular context, as the light chains of smooth muscle and nonmuscle myosin comigrate under native and denaturing electrophoresis techniques. Therefore, the regulatory light chains of smooth muscle myosin (SM-RLC) and nonmuscle myosin (NM-RLC) were purified, and these proteins were resolved by isoelectric focusing. Using this method, intact mouse aortic smooth muscle homogenates demonstrated four distinct RLC isoelectric variants. These spots were identified as phosphorylated NM-RLC (most acidic), nonphosphorylated NM-RLC, phosphorylated SM-RLC, and nonphosphorylated SM-RLC (most basic). During smooth muscle activation, NM-RLC phosphorylation increased. During depolarization, the increase in NM-RLC phosphorylation was unaffected by inhibition of either Rho kinase or PKC. However, inhibition of Rho kinase blocked the angiotensin II-induced increase in NM-RLC phosphorylation. Additionally, force for angiotensin II stimulation of aortic smooth muscle from heterozygous nonmuscle myosin IIB knockout mice was significantly less than that of wild-type littermates, suggesting that, in smooth muscle, activation of nonmuscle myosin is important for force maintenance. The data also demonstrate that, in smooth muscle, the activation of nonmuscle myosin is regulated by Ca(2+)-calmodulin-activated myosin light chain kinase during depolarization and a Rho kinase-dependent pathway during agonist stimulation.

TGF-beta1 inhibits Cx43 expression and formation of functional syncytia in cultured smooth muscle cells from human detrusor.

PubMed

Neuhaus, Jochen; Heinrich, Marco; Schwalenberg, Thilo; Stolzenburg, Jens-Uwe

2009-02-01

Human detrusor smooth muscle cells (hBSMCs) are coupled by connexin 43 (Cx43)-positive gap junctions to form functional syncytia. Gap junctional communication likely is necessary for synchronised detrusor contractions and is supposed to be altered in voiding disturbances. Other authors have shown that the pleiotropic cytokine TGF-beta1 upregulates Cx43 expression in human aortic smooth muscle cells. In this study, we examined the TGF-beta1 effects on Cx43 expression in cultured hBSMCs. hBSMC cultures, established from patients undergoing cystectomy, were treated with recombinant human TGF-beta1. Cx43 expression was then examined by Western blotting, real-time PCR, and immunocytochemistry. Dye-injection experiments were used to study the size of functional syncytia. Dye-coupling experiments revealed stable formation of functional syncytia in passaged cell cultures (P1-P4). Stimulation with TGF-beta1 led to significant reduction of Cx43 immunoreactivity and coupling. Cx43 protein expression was significantly downregulated and Cx43 mRNA was only 30% of the control level. Interestingly, low phosphorylation species of Cx43 were particularly affected. Our experiments demonstrated a significant down regulation of connexin 43 by TGF-beta1 in cultured hBSMCs. These findings support the view that TGF-beta1 is involved in the pathophysiology of urinary bladder dysfunction.

Length adaptation of airway smooth muscle.

PubMed

Bossé, Ynuk; Sobieszek, Apolinary; Paré, Peter D; Seow, Chun Y

2008-01-01

Many types of smooth muscle, including airway smooth muscle (ASM), are capable of generating maximal force over a large length range due to length adaptation, which is a relatively rapid process in which smooth muscle regains contractility after experiencing a force decrease induced by length fluctuation. Although the underlying mechanism is unclear, it is believed that structural malleability of smooth muscle cells is essential for the adaptation to occur. The process is triggered by strain on the cell cytoskeleton that results in a series of yet undefined biochemical and biophysical events leading to restructuring of the cytoskeleton and contractile apparatus and consequently optimization of the overlap between the myosin and actin filaments. Although length adaptability is an intrinsic property of smooth muscle, maladaptation of ASM could result in excessive constriction of the airways and the inability of deep inspirations to dilate them. In this article, we describe the phenomenon of length adaptation in ASM and some possible underlying mechanisms that involve the myosin filament assembly and disassembly. We discuss a possible role of maladaptation of ASM in the pathogenesis of asthma. We believe that length adaptation in ASM is mediated by specific proteins and their posttranslational regulations involving covalent modifications, such as phosphorylation. The discovery of these molecules and the processes that regulate their activity will greatly enhance our understanding of the basic mechanisms of ASM contraction and will suggest molecular targets to alleviate asthma exacerbation related to excessive constriction of the airways.

7 CFR 51.772 - Fairly smooth texture.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Definitions § 51.772 Fairly smooth texture. Fairly smooth texture means that the skin is fairly thin and not coarse for the variety and size of the fruit. “Fairly thin” means that the skin thickness does not...

7 CFR 51.772 - Fairly smooth texture.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Definitions § 51.772 Fairly smooth texture. Fairly smooth texture means that the skin is fairly thin and not coarse for the variety and size of the fruit. “Fairly thin” means that the skin thickness does not...

Dynamics of binary-disk interaction. 1: Resonances and disk gap sizes

NASA Technical Reports Server (NTRS)

Artymowicz, Pawel; Lubow, Stephen H.

1994-01-01

We investigate the gravitational interaction of a generally eccentric binary star system with circumbinary and circumstellar gaseous disks. The disks are assumed to be coplanar with the binary, geometrically thin, and primarily governed by gas pressure and (turbulent) viscosity but not self-gravity. Both ordinary and eccentric Lindblad resonances are primarily responsible for truncating the disks in binaries with arbitrary eccentricity and nonextreme mass ratio. Starting from a smooth disk configuration, after the gravitational field of the binary truncates the disk on the dynamical timescale, a quasi-equilibrium is achieved, in which the resonant and viscous torques balance each other and any changes in the structure of the disk (e.g., due to global viscous evolution) occur slowly, preserving the average size of the gap. We analytically compute the approximate sizes of disks (or disk gaps) as a function of binary mass ratio and eccentricity in this quasi-equilibrium. Comparing the gap sizes with results of direct simulations using the smoothed particle hydrodynamics (SPH), we obtain a good agreement. As a by-product of the computations, we verify that standard SPH codes can adequately represent the dynamics of disks with moderate viscosity, Reynolds number R approximately 10(exp 3). For typical viscous disk parameters, and with a denoting the binary semimajor axis, the inner edge location of a circumbinary disk varies from 1.8a to 2.6a with binary eccentricity increasing from 0 to 0.25. For eccentricities 0 less than e less than 0.75, the minimum separation between a component star and the circumbinary disk inner edge is greater than a. Our calculations are relevant, among others, to protobinary stars and the recently discovered T Tau pre-main-sequence binaries. We briefly examine the case of a pre-main-sequence spectroscopic binary GW Ori and conclude that circumbinary disk truncation to the size required by one proposed spectroscopic model cannot be due to

Dynamic Maternal Gradients Control Timing and Shift-Rates for Drosophila Gap Gene Expression

PubMed Central

Verd, Berta; Crombach, Anton

2017-01-01

Pattern formation during development is a highly dynamic process. In spite of this, few experimental and modelling approaches take into account the explicit time-dependence of the rules governing regulatory systems. We address this problem by studying dynamic morphogen interpretation by the gap gene network in Drosophila melanogaster. Gap genes are involved in segment determination during early embryogenesis. They are activated by maternal morphogen gradients encoded by bicoid (bcd) and caudal (cad). These gradients decay at the same time-scale as the establishment of the antero-posterior gap gene pattern. We use a reverse-engineering approach, based on data-driven regulatory models called gene circuits, to isolate and characterise the explicitly time-dependent effects of changing morphogen concentrations on gap gene regulation. To achieve this, we simulate the system in the presence and absence of dynamic gradient decay. Comparison between these simulations reveals that maternal morphogen decay controls the timing and limits the rate of gap gene expression. In the anterior of the embyro, it affects peak expression and leads to the establishment of smooth spatial boundaries between gap domains. In the posterior of the embryo, it causes a progressive slow-down in the rate of gap domain shifts, which is necessary to correctly position domain boundaries and to stabilise the spatial gap gene expression pattern. We use a newly developed method for the analysis of transient dynamics in non-autonomous (time-variable) systems to understand the regulatory causes of these effects. By providing a rigorous mechanistic explanation for the role of maternal gradient decay in gap gene regulation, our study demonstrates that such analyses are feasible and reveal important aspects of dynamic gene regulation which would have been missed by a traditional steady-state approach. More generally, it highlights the importance of transient dynamics for understanding complex regulatory

Dynamic Maternal Gradients Control Timing and Shift-Rates for Drosophila Gap Gene Expression.

PubMed

Verd, Berta; Crombach, Anton; Jaeger, Johannes

2017-02-01

Pattern formation during development is a highly dynamic process. In spite of this, few experimental and modelling approaches take into account the explicit time-dependence of the rules governing regulatory systems. We address this problem by studying dynamic morphogen interpretation by the gap gene network in Drosophila melanogaster. Gap genes are involved in segment determination during early embryogenesis. They are activated by maternal morphogen gradients encoded by bicoid (bcd) and caudal (cad). These gradients decay at the same time-scale as the establishment of the antero-posterior gap gene pattern. We use a reverse-engineering approach, based on data-driven regulatory models called gene circuits, to isolate and characterise the explicitly time-dependent effects of changing morphogen concentrations on gap gene regulation. To achieve this, we simulate the system in the presence and absence of dynamic gradient decay. Comparison between these simulations reveals that maternal morphogen decay controls the timing and limits the rate of gap gene expression. In the anterior of the embyro, it affects peak expression and leads to the establishment of smooth spatial boundaries between gap domains. In the posterior of the embryo, it causes a progressive slow-down in the rate of gap domain shifts, which is necessary to correctly position domain boundaries and to stabilise the spatial gap gene expression pattern. We use a newly developed method for the analysis of transient dynamics in non-autonomous (time-variable) systems to understand the regulatory causes of these effects. By providing a rigorous mechanistic explanation for the role of maternal gradient decay in gap gene regulation, our study demonstrates that such analyses are feasible and reveal important aspects of dynamic gene regulation which would have been missed by a traditional steady-state approach. More generally, it highlights the importance of transient dynamics for understanding complex regulatory

Microstructure and Mechanical Properties of Narrow Gap Laser-Arc Hybrid Welded 40 mm Thick Mild Steel.

PubMed

Zhang, Chen; Li, Geng; Gao, Ming; Zeng, XiaoYan

2017-01-26

Both laser-arc hybrid welding and narrow gap welding have potential for the fabrication of thick sections, but their combination has been seldom studied. In this research, 40 mm thick mild steel was welded by narrow gap laser-arc hybrid welding. A weld with smooth layer transition, free of visible defects, was obtained by nine passes at a 6 mm width narrow gap. The lower part of the weld has the lowest mechanical properties because of the lowest amount of acicular ferrite, but its ultimate tensile strength and impact absorbing energy is still 49% and 60% higher than those of base metal, respectively. The microhardness deviation of all filler layers along weld thickness direction is no more than 15 HV 0.2 , indicating that no temper softening appeared during multiple heat cycles. The results provide an alternative technique for improving the efficiency and quality of welding thick sections.

Microstructure and Mechanical Properties of Narrow Gap Laser-Arc Hybrid Welded 40 mm Thick Mild Steel

PubMed Central

Zhang, Chen; Li, Geng; Gao, Ming; Zeng, XiaoYan

2017-01-01

Both laser-arc hybrid welding and narrow gap welding have potential for the fabrication of thick sections, but their combination has been seldom studied. In this research, 40 mm thick mild steel was welded by narrow gap laser-arc hybrid welding. A weld with smooth layer transition, free of visible defects, was obtained by nine passes at a 6 mm width narrow gap. The lower part of the weld has the lowest mechanical properties because of the lowest amount of acicular ferrite, but its ultimate tensile strength and impact absorbing energy is still 49% and 60% higher than those of base metal, respectively. The microhardness deviation of all filler layers along weld thickness direction is no more than 15 HV0.2, indicating that no temper softening appeared during multiple heat cycles. The results provide an alternative technique for improving the efficiency and quality of welding thick sections. PMID:28772469

Smoothing-based compressed state Kalman filter for joint state-parameter estimation: Applications in reservoir characterization and CO2 storage monitoring

NASA Astrophysics Data System (ADS)

Li, Y. J.; Kokkinaki, Amalia; Darve, Eric F.; Kitanidis, Peter K.

2017-08-01

The operation of most engineered hydrogeological systems relies on simulating physical processes using numerical models with uncertain parameters and initial conditions. Predictions by such uncertain models can be greatly improved by Kalman-filter techniques that sequentially assimilate monitoring data. Each assimilation constitutes a nonlinear optimization, which is solved by linearizing an objective function about the model prediction and applying a linear correction to this prediction. However, if model parameters and initial conditions are uncertain, the optimization problem becomes strongly nonlinear and a linear correction may yield unphysical results. In this paper, we investigate the utility of one-step ahead smoothing, a variant of the traditional filtering process, to eliminate nonphysical results and reduce estimation artifacts caused by nonlinearities. We present the smoothing-based compressed state Kalman filter (sCSKF), an algorithm that combines one step ahead smoothing, in which current observations are used to correct the state and parameters one step back in time, with a nonensemble covariance compression scheme, that reduces the computational cost by efficiently exploring the high-dimensional state and parameter space. Numerical experiments show that when model parameters are uncertain and the states exhibit hyperbolic behavior with sharp fronts, as in CO2 storage applications, one-step ahead smoothing reduces overshooting errors and, by design, gives physically consistent state and parameter estimates. We compared sCSKF with commonly used data assimilation methods and showed that for the same computational cost, combining one step ahead smoothing and nonensemble compression is advantageous for real-time characterization and monitoring of large-scale hydrogeological systems with sharp moving fronts.

Differences in time to peak carbachol-induced contractions between circular and longitudinal smooth muscles of mouse ileum.

PubMed

Azuma, Yasu-Taka; Samezawa, Nanako; Nishiyama, Kazuhiro; Nakajima, Hidemitsu; Takeuchi, Tadayoshi

2016-01-01

The muscular layer in the GI tract consists of an inner circular muscular layer and an outer longitudinal muscular layer. Acetylcholine (ACh) is the representative neurotransmitter that causes contractions in the gastrointestinal tracts of most animal species. There are many reports of muscarinic receptor-mediated contraction of longitudinal muscles, but few studies discuss circular muscles. The present study detailed the contractile response in the circular smooth muscles of the mouse ileum. We used small muscle strips (0.2 mm × 1 mm) and large muscle strips (4 × 4 mm) isolated from the circular and longitudinal muscle layers of the mouse ileum to compare contraction responses in circular and longitudinal smooth muscles. The time to peak contractile responses to carbamylcholine (CCh) were later in the small muscle strips (0.2 × 1 mm) of circular muscle (5.7 min) than longitudinal muscles (0.4 min). The time to peak contractile responses to CCh in the large muscle strips (4 × 4 mm) were also later in the circular muscle (3.1 min) than the longitudinal muscle (1.4 min). Furthermore, a muscarinic M2 receptor antagonist and gap junction inhibitor significantly delayed the time to peak contraction of the large muscle strips (4 × 4 mm) from the circular muscular layer. Our findings indicate that muscarinic M2 receptors in the circular muscular layer of mouse ileum exert a previously undocumented function in gut motility via the regulation of gap junctions.

Nonparametric Signal Extraction and Measurement Error in the Analysis of Electroencephalographic Activity During Sleep

PubMed Central

Crainiceanu, Ciprian M.; Caffo, Brian S.; Di, Chong-Zhi; Punjabi, Naresh M.

2009-01-01

We introduce methods for signal and associated variability estimation based on hierarchical nonparametric smoothing with application to the Sleep Heart Health Study (SHHS). SHHS is the largest electroencephalographic (EEG) collection of sleep-related data, which contains, at each visit, two quasi-continuous EEG signals for each subject. The signal features extracted from EEG data are then used in second level analyses to investigate the relation between health, behavioral, or biometric outcomes and sleep. Using subject specific signals estimated with known variability in a second level regression becomes a nonstandard measurement error problem. We propose and implement methods that take into account cross-sectional and longitudinal measurement error. The research presented here forms the basis for EEG signal processing for the SHHS. PMID:20057925

Benzodiazepines impair smooth pursuit eye movements.

PubMed Central

Bittencourt, P R; Wade, P; Smith, A T; Richens, A

1983-01-01

Five healthy male volunteers received single oral doses of 10 mg diazepam, 20 mg temazepam and placebo, in a double-blind, randomised fashion. Smooth pursuit eye movement velocity and serum benzodiazepine concentration were measured before and after at 0.5,1,1.5,2,3,4,6,9 and 12 h after administration of the treatments. Significant decrease in smooth pursuit eye movement velocity as compared to placebo was observed between 0.5-2 h after temazepam, and between 1-2 h after diazepam. Smooth pursuit eye movement velocity was log-linearly correlated with serum temazepam and diazepam concentration. The results demonstrate the relationship between serum benzodiazepine concentration and its effect on an objective measure of oculomotor performance. PMID:6133544

On smoothness of black saturns

NASA Astrophysics Data System (ADS)

Chruściel, Piotr T.; Eckstein, Michał; Szybka, Sebastian J.

2010-11-01

We prove smoothness of the domain of outer communications (d.o.c.) of the Black Saturn solutions of Elvang and Figueras. We show that the metric on the d.o.c. extends smoothly across two disjoint event horizons with topology mathbb{R} × {S^3} and mathbb{R} × {S^1} × {S^2} . We establish stable causality of the d.o.c. when the Komar angular momentum of the spherical component of the horizon vanishes, and present numerical evidence for stable causality in general.

A correction method for systematic error in (1)H-NMR time-course data validated through stochastic cell culture simulation.

PubMed

Sokolenko, Stanislav; Aucoin, Marc G

2015-09-04

The growing ubiquity of metabolomic techniques has facilitated high frequency time-course data collection for an increasing number of applications. While the concentration trends of individual metabolites can be modeled with common curve fitting techniques, a more accurate representation of the data needs to consider effects that act on more than one metabolite in a given sample. To this end, we present a simple algorithm that uses nonparametric smoothing carried out on all observed metabolites at once to identify and correct systematic error from dilution effects. In addition, we develop a simulation of metabolite concentration time-course trends to supplement available data and explore algorithm performance. Although we focus on nuclear magnetic resonance (NMR) analysis in the context of cell culture, a number of possible extensions are discussed. Realistic metabolic data was successfully simulated using a 4-step process. Starting with a set of metabolite concentration time-courses from a metabolomic experiment, each time-course was classified as either increasing, decreasing, concave, or approximately constant. Trend shapes were simulated from generic functions corresponding to each classification. The resulting shapes were then scaled to simulated compound concentrations. Finally, the scaled trends were perturbed using a combination of random and systematic errors. To detect systematic errors, a nonparametric fit was applied to each trend and percent deviations calculated at every timepoint. Systematic errors could be identified at time-points where the median percent deviation exceeded a threshold value, determined by the choice of smoothing model and the number of observed trends. Regardless of model, increasing the number of observations over a time-course resulted in more accurate error estimates, although the improvement was not particularly large between 10 and 20 samples per trend. The presented algorithm was able to identify systematic errors as small

Deformation Time-Series of the Lost-Hills Oil Field using a Multi-Baseline Interferometric SAR Inversion Algorithm with Finite Difference Smoothing Constraints

NASA Astrophysics Data System (ADS)

Werner, C. L.; Wegmüller, U.; Strozzi, T.

2012-12-01

The Lost-Hills oil field located in Kern County,California ranks sixth in total remaining reserves in California. Hundreds of densely packed wells characterize the field with one well every 5000 to 20000 square meters. Subsidence due to oil extraction can be grater than 10 cm/year and is highly variable both in space and time. The RADARSAT-1 SAR satellite collected data over this area with a 24-day repeat during a 2 year period spanning 2002-2004. Relatively high interferometric correlation makes this an excellent region for development and test of deformation time-series inversion algorithms. Errors in deformation time series derived from a stack of differential interferograms are primarily due to errors in the digital terrain model, interferometric baselines, variability in tropospheric delay, thermal noise and phase unwrapping errors. Particularly challenging is separation of non-linear deformation from variations in troposphere delay and phase unwrapping errors. In our algorithm a subset of interferometric pairs is selected from a set of N radar acquisitions based on criteria of connectivity, time interval, and perpendicular baseline. When possible, the subset consists of temporally connected interferograms, otherwise the different groups of interferograms are selected to overlap in time. The maximum time interval is constrained to be less than a threshold value to minimize phase gradients due to deformation as well as minimize temporal decorrelation. Large baselines are also avoided to minimize the consequence of DEM errors on the interferometric phase. Based on an extension of the SVD based inversion described by Lee et al. ( USGS Professional Paper 1769), Schmidt and Burgmann (JGR, 2003), and the earlier work of Berardino (TGRS, 2002), our algorithm combines estimation of the DEM height error with a set of finite difference smoothing constraints. A set of linear equations are formulated for each spatial point that are functions of the deformation velocities

von Kármán swirling flow between a rotating and a stationary smooth disk: Experiment

NASA Astrophysics Data System (ADS)

Mukherjee, Aryesh; Steinberg, Victor

2018-01-01

Precise measurements of the torque in a von Kármán swirling flow between a rotating and a stationary smooth disk in three Newtonian fluids with different dynamic viscosities are reported. From these measurements the dependence of the normalized torque, called the friction coefficient, on Re is found to be of the form Cf=1.17 (±0.03 ) Re-0.46±0.003 where the scaling exponent and coefficient are close to that predicted theoretically for an infinite, unshrouded, and smooth rotating disk which follows from an exact similarity solution of the Navier-Stokes equations, obtained by von Kármán. An error analysis shows that deviations from the theory can be partially caused by background errors. Measurements of the azimuthal Vθ and axial velocity profiles along radial and axial directions reveal that the flow core rotates at Vθ/r Ω ≃0.22 (up to z ≈4 cm from the rotating disk and up to r0/R ≃0.25 in the radial direction) in spite of the small aspect ratio of the vessel. Thus the friction coefficient shows scaling close to that obtained from the von Kármán exact similarity solution, but the observed rotating core provides evidence of the Batchelor-like solution [Q. J. Mech. Appl. Math. 4, 29 (1951), 10.1093/qjmam/4.1.29] different from the von Kármán [Z. Angew. Math. Mech. 1, 233 (1921), 10.1002/zamm.19210010401] or Stewartson [Proc. Camb. Philos. Soc. 49, 333 (1953), 10.1017/S0305004100028437] one.

Graphene-based topological insulator with an intrinsic bulk band gap above room temperature.

PubMed

Kou, Liangzhi; Yan, Binghai; Hu, Feiming; Wu, Shu-Chun; Wehling, Tim O; Felser, Claudia; Chen, Changfeng; Frauenheim, Thomas

2013-01-01

Topological insulators (TIs) represent a new quantum state of matter characterized by robust gapless states inside the insulating bulk gap. The metallic edge states of a two-dimensional (2D) TI, known as the quantum spin Hall (QSH) effect, are immune to backscattering and carry fully spin-polarized dissipationless currents. However, existing 2D TIs realized in HgTe and InAs/GaSb suffer from small bulk gaps (<10 meV) well below room temperature, thus limiting their application in electronic and spintronic devices. Here, we report a new 2D TI comprising a graphene layer sandwiched between two Bi2Se3 slabs that exhibits a large intrinsic bulk band gap of 30-50 meV, making it viable for room-temperature applications. Distinct from previous strategies for enhancing the intrinsic spin-orbit coupling effect of the graphene lattice, the present graphene-based TI operates on a new mechanism of strong inversion between graphene Dirac bands and Bi2Se3 conduction bands. Strain engineering leads to effective control and substantial enhancement of the bulk gap. Recently reported synthesis of smooth graphene/Bi2Se3 interfaces demonstrates the feasibility of experimental realization of this new 2D TI structure, which holds great promise for nanoscale device applications.

Nutrition Smoothing: Can Proximity to Towns and Cities Protect Rural Children against Seasonal Variation in Agroclimatic Conditions at Birth?

PubMed

Darrouzet-Nardi, Amelia F; Masters, William A

2017-01-01

A large literature links early-life environmental shocks to later outcomes. This paper uses seasonal variation across the Democratic Republic of the Congo to test for nutrition smoothing, defined here as attaining similar height, weight and mortality outcomes despite different agroclimatic conditions at birth. We find that gaps between siblings and neighbors born at different times of year are larger in more remote rural areas, farther from the equator where there are greater seasonal differences in rainfall and temperature. For those born at adverse times in places with pronounced seasonality, the gains associated with above-median proximity to nearby towns are similar to rising one quintile in the national distribution of household wealth for mortality, and two quintiles for attained height. Smoothing of outcomes could involve a variety of mechanisms to be addressed in future work, including access to food markets, health services, public assistance and temporary migration to achieve more uniform dietary intake, or less exposure and improved recovery from seasonal diseases.

Thermal smoothing of rough surfaces in vacuo

NASA Technical Reports Server (NTRS)

Wahl, G.

1986-01-01

The derivation of equations governing the smoothing of rough surfaces, based on Mullins' (1957, 1960, and 1963) theories of thermal grooving and of capillarity-governed solid surface morphology is presented. As an example, the smoothing of a one-dimensional sine-shaped surface is discussed.

The evolutionary origin of bilaterian smooth and striated myocytes

PubMed Central

Brunet, Thibaut; Fischer, Antje HL; Steinmetz, Patrick RH; Lauri, Antonella; Bertucci, Paola; Arendt, Detlev

2016-01-01

The dichotomy between smooth and striated myocytes is fundamental for bilaterian musculature, but its evolutionary origin is unsolved. In particular, interrelationships of visceral smooth muscles remain unclear. Absent in fly and nematode, they have not yet been characterized molecularly outside vertebrates. Here, we characterize expression profile, ultrastructure, contractility and innervation of the musculature in the marine annelid Platynereis dumerilii and identify smooth muscles around the midgut, hindgut and heart that resemble their vertebrate counterparts in molecular fingerprint, contraction speed and nervous control. Our data suggest that both visceral smooth and somatic striated myocytes were present in the protostome-deuterostome ancestor and that smooth myocytes later co-opted the striated contractile module repeatedly – for example, in vertebrate heart evolution. During these smooth-to-striated myocyte conversions, the core regulatory complex of transcription factors conveying myocyte identity remained unchanged, reflecting a general principle in cell type evolution. DOI: http://dx.doi.org/10.7554/eLife.19607.001 PMID:27906129

Interstitial Cells: Regulators of Smooth Muscle Function

PubMed Central

Sanders, Kenton M.; Ward, Sean M.; Koh, Sang Don

2014-01-01

Smooth muscles are complex tissues containing a variety of cells in addition to muscle cells. Interstitial cells of mesenchymal origin interact with and form electrical connectivity with smooth muscle cells in many organs, and these cells provide important regulatory functions. For example, in the gastrointestinal tract, interstitial cells of Cajal (ICC) and PDGFRα+ cells have been described, in detail, and represent distinct classes of cells with unique ultrastructure, molecular phenotypes, and functions. Smooth muscle cells are electrically coupled to ICC and PDGFRα+ cells, forming an integrated unit called the SIP syncytium. SIP cells express a variety of receptors and ion channels, and conductance changes in any type of SIP cell affect the excitability and responses of the syncytium. SIP cells are known to provide pacemaker activity, propagation pathways for slow waves, transduction of inputs from motor neurons, and mechanosensitivity. Loss of interstitial cells has been associated with motor disorders of the gut. Interstitial cells are also found in a variety of other smooth muscles; however, in most cases, the physiological and pathophysiological roles for these cells have not been clearly defined. This review describes structural, functional, and molecular features of interstitial cells and discusses their contributions in determining the behaviors of smooth muscle tissues. PMID:24987007

Quantification of residual dose estimation error on log file-based patient dose calculation.

PubMed

Katsuta, Yoshiyuki; Kadoya, Noriyuki; Fujita, Yukio; Shimizu, Eiji; Matsunaga, Kenichi; Matsushita, Haruo; Majima, Kazuhiro; Jingu, Keiichi

2016-05-01

The log file-based patient dose estimation includes a residual dose estimation error caused by leaf miscalibration, which cannot be reflected on the estimated dose. The purpose of this study is to determine this residual dose estimation error. Modified log files for seven head-and-neck and prostate volumetric modulated arc therapy (VMAT) plans simulating leaf miscalibration were generated by shifting both leaf banks (systematic leaf gap errors: ±2.0, ±1.0, and ±0.5mm in opposite directions and systematic leaf shifts: ±1.0mm in the same direction) using MATLAB-based (MathWorks, Natick, MA) in-house software. The generated modified and non-modified log files were imported back into the treatment planning system and recalculated. Subsequently, the generalized equivalent uniform dose (gEUD) was quantified for the definition of the planning target volume (PTV) and organs at risks. For MLC leaves calibrated within ±0.5mm, the quantified residual dose estimation errors that obtained from the slope of the linear regression of gEUD changes between non- and modified log file doses per leaf gap are in head-and-neck plans 1.32±0.27% and 0.82±0.17Gy for PTV and spinal cord, respectively, and in prostate plans 1.22±0.36%, 0.95±0.14Gy, and 0.45±0.08Gy for PTV, rectum, and bladder, respectively. In this work, we determine the residual dose estimation errors for VMAT delivery using the log file-based patient dose calculation according to the MLC calibration accuracy. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

L2CXCV: A Fortran 77 package for least squares convex/concave data smoothing

NASA Astrophysics Data System (ADS)

Demetriou, I. C.

2006-04-01

Fortran 77 software is given for least squares smoothing to data values contaminated by random errors subject to one sign change in the second divided differences of the smoothed values, where the location of the sign change is also unknown of the optimization problem. A highly useful description of the constraints is that they follow from the assumption of initially increasing and subsequently decreasing rates of change, or vice versa, of the process considered. The underlying algorithm partitions the data into two disjoint sets of adjacent data and calculates the required fit by solving a strictly convex quadratic programming problem for each set. The piecewise linear interpolant to the fit is convex on the first set and concave on the other one. The partition into suitable sets is achieved by a finite iterative algorithm, which is made quite efficient because of the interactions of the quadratic programming problems on consecutive data. The algorithm obtains the solution by employing no more quadratic programming calculations over subranges of data than twice the number of the divided differences constraints. The quadratic programming technique makes use of active sets and takes advantage of a B-spline representation of the smoothed values that allows some efficient updating procedures. The entire code required to implement the method is 2920 Fortran lines. The package has been tested on a variety of data sets and it has performed very efficiently, terminating in an overall number of active set changes over subranges of data that is only proportional to the number of data. The results suggest that the package can be used for very large numbers of data values. Some examples with output are provided to help new users and exhibit certain features of the software. Important applications of the smoothing technique may be found in calculating a sigmoid approximation, which is a common topic in various contexts in applications in disciplines like physics, economics

Alternative Smoothing and Scaling Strategies for Weighted Composite Scores

ERIC Educational Resources Information Center

Moses, Tim

2014-01-01

In this study, smoothing and scaling approaches are compared for estimating subscore-to-composite scaling results involving composites computed as rounded and weighted combinations of subscores. The considered smoothing and scaling approaches included those based on raw data, on smoothing the bivariate distribution of the subscores, on smoothing…

Anticipatory Smooth Eye Movements in Autism Spectrum Disorder

PubMed Central

Aitkin, Cordelia D.; Santos, Elio M.; Kowler, Eileen

2013-01-01

Smooth pursuit eye movements are important for vision because they maintain the line of sight on targets that move smoothly within the visual field. Smooth pursuit is driven by neural representations of motion, including a surprisingly strong influence of high-level signals representing expected motion. We studied anticipatory smooth eye movements (defined as smooth eye movements in the direction of expected future motion) produced by salient visual cues in a group of high-functioning observers with Autism Spectrum Disorder (ASD), a condition that has been associated with difficulties in either generating predictions, or translating predictions into effective motor commands. Eye movements were recorded while participants pursued the motion of a disc that moved within an outline drawing of an inverted Y-shaped tube. The cue to the motion path was a visual barrier that blocked the untraveled branch (right or left) of the tube. ASD participants showed strong anticipatory smooth eye movements whose velocity was the same as that of a group of neurotypical participants. Anticipatory smooth eye movements appeared on the very first cued trial, indicating that trial-by-trial learning was not responsible for the responses. These results are significant because they show that anticipatory capacities are intact in high-functioning ASD in cases where the cue to the motion path is highly salient and unambiguous. Once the ability to generate anticipatory pursuit is demonstrated, the study of the anticipatory responses with a variety of types of cues provides a window into the perceptual or cognitive processes that underlie the interpretation of events in natural environments or social situations. PMID:24376667

Anticipatory smooth eye movements in autism spectrum disorder.

PubMed

Aitkin, Cordelia D; Santos, Elio M; Kowler, Eileen

2013-01-01

Smooth pursuit eye movements are important for vision because they maintain the line of sight on targets that move smoothly within the visual field. Smooth pursuit is driven by neural representations of motion, including a surprisingly strong influence of high-level signals representing expected motion. We studied anticipatory smooth eye movements (defined as smooth eye movements in the direction of expected future motion) produced by salient visual cues in a group of high-functioning observers with Autism Spectrum Disorder (ASD), a condition that has been associated with difficulties in either generating predictions, or translating predictions into effective motor commands. Eye movements were recorded while participants pursued the motion of a disc that moved within an outline drawing of an inverted Y-shaped tube. The cue to the motion path was a visual barrier that blocked the untraveled branch (right or left) of the tube. ASD participants showed strong anticipatory smooth eye movements whose velocity was the same as that of a group of neurotypical participants. Anticipatory smooth eye movements appeared on the very first cued trial, indicating that trial-by-trial learning was not responsible for the responses. These results are significant because they show that anticipatory capacities are intact in high-functioning ASD in cases where the cue to the motion path is highly salient and unambiguous. Once the ability to generate anticipatory pursuit is demonstrated, the study of the anticipatory responses with a variety of types of cues provides a window into the perceptual or cognitive processes that underlie the interpretation of events in natural environments or social situations.

Mechanisms of mechanical strain memory in airway smooth muscle.

PubMed

Kim, Hak Rim; Hai, Chi-Ming

2005-10-01

We evaluated the hypothesis that mechanical deformation of airway smooth muscle induces structural remodeling of airway smooth muscle cells, thereby modulating mechanical performance in subsequent contractions. This hypothesis implied that past experience of mechanical deformation was retained (or "memorized") as structural changes in airway smooth muscle cells, which modulated the cell's subsequent contractile responses. We termed this phenomenon mechanical strain memory. Preshortening has been found to induce attenuation of both force and isotonic shortening velocity in cholinergic receptor-activated airway smooth muscle. Rapid stretching of cholinergic receptor-activated airway smooth muscle from an initial length to a final length resulted in post-stretch force and myosin light chain phosphorylation that correlated significantly with initial length. Thus post-stretch muscle strips appeared to retain memory of the initial length prior to rapid stretch (mechanical strain memory). Cytoskeletal recruitment of actin- and integrin-binding proteins and Erk 1/2 MAPK appeared to be important mechanisms of mechanical strain memory. Sinusoidal length oscillation led to force attenuation during oscillation and in subsequent contractions in intact airway smooth muscle, and p38 MAPK appeared to be an important mechanism. In contrast, application of local mechanical strain to cultured airway smooth muscle cells induced local actin polymerization and cytoskeletal stiffening. It is conceivable that deep inspiration-induced bronchoprotection may be a manifestation of mechanical strain memory such that mechanical deformation from past breathing cycles modulated the mechanical performance of airway smooth muscle in subsequent cycles in a continuous and dynamic manner.

Calculation of smooth potential energy surfaces using local electron correlation methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mata, Ricardo A.; Werner, Hans-Joachim

2006-11-14

The geometry dependence of excitation domains in local correlation methods can lead to noncontinuous potential energy surfaces. We propose a simple domain merging procedure which eliminates this problem in many situations. The method is applied to heterolytic bond dissociations of ketene and propadienone, to SN2 reactions of Cl{sup -} with alkylchlorides, and in a quantum mechanical/molecular mechanical study of the chorismate mutase enzyme. It is demonstrated that smooth potentials are obtained in all cases. Furthermore, basis set superposition error effects are reduced in local calculations, and it is found that this leads to better basis set convergence when computing barriermore » heights or weak interactions. When the electronic structure strongly changes between reactants or products and the transition state, the domain merging procedure leads to a balanced description of all structures and accurate barrier heights.« less

Complexity of possibly gapped histogram and analysis of histogram.

PubMed

Fushing, Hsieh; Roy, Tania

2018-02-01

We demonstrate that gaps and distributional patterns embedded within real-valued measurements are inseparable biological and mechanistic information contents of the system. Such patterns are discovered through data-driven possibly gapped histogram, which further leads to the geometry-based analysis of histogram (ANOHT). Constructing a possibly gapped histogram is a complex problem of statistical mechanics due to the ensemble of candidate histograms being captured by a two-layer Ising model. This construction is also a distinctive problem of Information Theory from the perspective of data compression via uniformity. By defining a Hamiltonian (or energy) as a sum of total coding lengths of boundaries and total decoding errors within bins, this issue of computing the minimum energy macroscopic states is surprisingly resolved by applying the hierarchical clustering algorithm. Thus, a possibly gapped histogram corresponds to a macro-state. And then the first phase of ANOHT is developed for simultaneous comparison of multiple treatments, while the second phase of ANOHT is developed based on classical empirical process theory for a tree-geometry that can check the authenticity of branches of the treatment tree. The well-known Iris data are used to illustrate our technical developments. Also, a large baseball pitching dataset and a heavily right-censored divorce data are analysed to showcase the existential gaps and utilities of ANOHT.

Complexity of possibly gapped histogram and analysis of histogram

PubMed Central

Roy, Tania

2018-01-01

We demonstrate that gaps and distributional patterns embedded within real-valued measurements are inseparable biological and mechanistic information contents of the system. Such patterns are discovered through data-driven possibly gapped histogram, which further leads to the geometry-based analysis of histogram (ANOHT). Constructing a possibly gapped histogram is a complex problem of statistical mechanics due to the ensemble of candidate histograms being captured by a two-layer Ising model. This construction is also a distinctive problem of Information Theory from the perspective of data compression via uniformity. By defining a Hamiltonian (or energy) as a sum of total coding lengths of boundaries and total decoding errors within bins, this issue of computing the minimum energy macroscopic states is surprisingly resolved by applying the hierarchical clustering algorithm. Thus, a possibly gapped histogram corresponds to a macro-state. And then the first phase of ANOHT is developed for simultaneous comparison of multiple treatments, while the second phase of ANOHT is developed based on classical empirical process theory for a tree-geometry that can check the authenticity of branches of the treatment tree. The well-known Iris data are used to illustrate our technical developments. Also, a large baseball pitching dataset and a heavily right-censored divorce data are analysed to showcase the existential gaps and utilities of ANOHT. PMID:29515829

Complexity of possibly gapped histogram and analysis of histogram

NASA Astrophysics Data System (ADS)

Fushing, Hsieh; Roy, Tania

2018-02-01

We demonstrate that gaps and distributional patterns embedded within real-valued measurements are inseparable biological and mechanistic information contents of the system. Such patterns are discovered through data-driven possibly gapped histogram, which further leads to the geometry-based analysis of histogram (ANOHT). Constructing a possibly gapped histogram is a complex problem of statistical mechanics due to the ensemble of candidate histograms being captured by a two-layer Ising model. This construction is also a distinctive problem of Information Theory from the perspective of data compression via uniformity. By defining a Hamiltonian (or energy) as a sum of total coding lengths of boundaries and total decoding errors within bins, this issue of computing the minimum energy macroscopic states is surprisingly resolved by applying the hierarchical clustering algorithm. Thus, a possibly gapped histogram corresponds to a macro-state. And then the first phase of ANOHT is developed for simultaneous comparison of multiple treatments, while the second phase of ANOHT is developed based on classical empirical process theory for a tree-geometry that can check the authenticity of branches of the treatment tree. The well-known Iris data are used to illustrate our technical developments. Also, a large baseball pitching dataset and a heavily right-censored divorce data are analysed to showcase the existential gaps and utilities of ANOHT.

Smoluchowski Equation for Networks: Merger Induced Intermittent Giant Node Formation and Degree Gap

NASA Astrophysics Data System (ADS)

Goto, Hayato; Viegas, Eduardo; Jensen, Henrik Jeldtoft; Takayasu, Hideki; Takayasu, Misako

2018-06-01

The dynamical phase diagram of a network undergoing annihilation, creation, and coagulation of nodes is found to exhibit two regimes controlled by the combined effect of preferential attachment for initiator and target nodes during coagulation and for link assignment to new nodes. The first regime exhibits smooth dynamics and power law degree distributions. In the second regime, giant degree nodes and gaps in the degree distribution are formed intermittently. Data for the Japanese firm network in 1994 and 2014 suggests that this network is moving towards the intermittent switching region.

Cost of close the gap for vision of Indigenous Australians: On estimating the extra resources required.

PubMed

Hsueh, Ya-seng Arthur; Brando, Alex; Dunt, David; Anjou, Mitchell D; Boudville, Andrea; Taylor, Hugh

2013-12-01

To estimate the costs of the extra resources required to close the gap of vision between Indigenous and non-Indigenous Australians. Constructing comprehensive eye care pathways for Indigenous Australians with their related probabilities, to capture full eye care usage compared with current usage rate for cataract surgery, refractive error and diabetic retinopathy using the best available data. Urban and remote regions of Australia. The provision of eye care for cataract surgery, refractive error and diabetic retinopathy. Estimated cost needed for full access, estimated current spending and estimated extra cost required to close the gaps of cataract surgery, refractive error and diabetic retinopathy for Indigenous Australians. Total cost needed for full coverage of all three major eye conditions is $45.5 million per year in 2011 Australian dollars. Current annual spending is $17.4 million. Additional yearly cost required to close the gap of vision is $28 million. This includes extra-capped funds of $3 million from the Commonwealth Government and $2 million from the State and Territory Governments. Additional coordination costs per year are $13.3 million. Although available data are limited, this study has produced the first estimates that are indicative of the need for planning and provide equity in eye care. © 2013 The Authors. Australian Journal of Rural Health © National Rural Health Alliance Inc.

Action errors, error management, and learning in organizations.

PubMed

Frese, Michael; Keith, Nina

2015-01-03

Every organization is confronted with errors. Most errors are corrected easily, but some may lead to negative consequences. Organizations often focus on error prevention as a single strategy for dealing with errors. Our review suggests that error prevention needs to be supplemented by error management--an approach directed at effectively dealing with errors after they have occurred, with the goal of minimizing negative and maximizing positive error consequences (examples of the latter are learning and innovations). After defining errors and related concepts, we review research on error-related processes affected by error management (error detection, damage control). Empirical evidence on positive effects of error management in individuals and organizations is then discussed, along with emotional, motivational, cognitive, and behavioral pathways of these effects. Learning from errors is central, but like other positive consequences, learning occurs under certain circumstances--one being the development of a mind-set of acceptance of human error.

Visual Short-Term Memory During Smooth Pursuit Eye Movements

ERIC Educational Resources Information Center

Kerzel, Dirk; Ziegler, Nathalie E.

2005-01-01

Visual short-term memory (VSTM) was probed while observers performed smooth pursuit eye movements. Smooth pursuit keeps a moving object stabilized in the fovea. VSTM capacity for position was reduced during smooth pursuit compared with a condition with eye fixation. There was no difference between a condition in which the items were approximately…

[Phenylephrine dosing error in Intensive Care Unit. Case of the trimester].

PubMed

2013-01-01

A real clinical case reported to SENSAR is presented. A patient admitted to the surgical intensive care unit following a lung resection, suffered arterial hypotension. The nurse was asked to give the patient 1 mL of phenylephrine. A few seconds afterwards, the patient experienced a hypertensive crisis, which resolved spontaneously without damage. Thereafter, the nurse was interviewed and a dosing error was identified: she had mistakenly given the patient 1 mg of phenylephrine (1 mL) instead of 100 mcg (1 mL of the standard dilution, 1mg in 10 mL). The incident analysis revealed latent factors (event triggers) due to the lack of protocols and standard operating procedures, communication errors among team members (physician-nurse), suboptimal training, and underdeveloped safety culture. In order to preempt similar incidents in the future, the following actions were implemented in the surgical intensive care unit: a protocol for bolus and short lived infusions (<30 min) was developed and to close the communication gap through the adoption of communication techniques. The protocol was designed by physicians and nurses to standardize the administration of drugs with high potential for errors. To close the communication gap, repeated checks about saying and understanding was proposed ("closed loop"). Labeling syringes with the drug dilution was also recommended. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

Modeling coherent errors in quantum error correction

NASA Astrophysics Data System (ADS)

Greenbaum, Daniel; Dutton, Zachary

2018-01-01

Analysis of quantum error correcting codes is typically done using a stochastic, Pauli channel error model for describing the noise on physical qubits. However, it was recently found that coherent errors (systematic rotations) on physical data qubits result in both physical and logical error rates that differ significantly from those predicted by a Pauli model. Here we examine the accuracy of the Pauli approximation for noise containing coherent errors (characterized by a rotation angle ɛ) under the repetition code. We derive an analytic expression for the logical error channel as a function of arbitrary code distance d and concatenation level n, in the small error limit. We find that coherent physical errors result in logical errors that are partially coherent and therefore non-Pauli. However, the coherent part of the logical error is negligible at fewer than {ε }-({dn-1)} error correction cycles when the decoder is optimized for independent Pauli errors, thus providing a regime of validity for the Pauli approximation. Above this number of correction cycles, the persistent coherent logical error will cause logical failure more quickly than the Pauli model would predict, and this may need to be combated with coherent suppression methods at the physical level or larger codes.

The biophysics of asthmatic airway smooth muscle.

PubMed

Stephens, Newman L; Li, Weilong; Jiang, He; Unruh, H; Ma, Xuefei

2003-09-16

It is clear that significant advances have been made in the understanding of the physiology, biochemistry and molecular biology of airway smooth muscle (ASM) contraction and how the knowledge obtained from these approaches may be used to elucidate the pathogenesis of asthma. Not to belittle other theories of smooth muscle contraction extant in the field, perhaps the most outstanding development has been the formulation of plasticity theory. This may radically alter our understanding of smooth muscle contraction. Its message is that while shortening velocity and capacity are linear functions of length, active force is length independent. These changes are explained by the ability of thick filament protein to depolymerize at short lengths and to increase numbers of contractile units in series at lengths greater than optimal length or L(ref). Other advances are represented by the report that the major part of ASM shortening is complete within the initial first 20% of contraction time, that the nature and history of loading determine the extent of shortening and that these findings can be explained by the finding that the crossbridges are cycling four times faster than in the remaining time. Another unexpected finding is that late in the course of isotonic relaxation the muscle undergoes spontaneous activation which delays relaxation and smoothes it out; speculatively this could minimize turbulence of airflow. On the applied front evidence now shows the shortening ability of bronchial smooth muscle of human subjects of asthma is significantly increased. Measurements also indicate that increased smooth muscle myosin light chain kinase content, via increased actomyosin ATPase activity could be responsible for the changes in contractility.

A four-component model of the action potential in mouse detrusor smooth muscle cell

PubMed Central

Brain, Keith L.; Young, John S.; Manchanda, Rohit

2018-01-01

Background and hypothesis Detrusor smooth muscle cells (DSMCs) of the urinary bladder are electrically connected to one another via gap junctions and form a three dimensional syncytium. DSMCs exhibit spontaneous electrical activity, including passive depolarizations and action potentials. The shapes of spontaneous action potentials (sAPs) observed from a single DSM cell can vary widely. The biophysical origins of this variability, and the precise components which contribute to the complex shapes observed are not known. To address these questions, the basic components which constitute the sAPs were investigated. We hypothesized that linear combinations of scaled versions of these basic components can produce sAP shapes observed in the syncytium. Methods and results The basic components were identified as spontaneous evoked junction potentials (sEJP), native AP (nAP), slow after hyperpolarization (sAHP) and very slow after hyperpolarization (vsAHP). The experimental recordings were grouped into two sets: a training data set and a testing data set. A training set was used to estimate the components, and a test set to evaluate the efficiency of the estimated components. We found that a linear combination of the identified components when appropriately amplified and time shifted replicated various AP shapes to a high degree of similarity, as quantified by the root mean square error (RMSE) measure. Conclusions We conclude that the four basic components—sEJP, nAP, sAHP, and vsAHP—identified and isolated in this work are necessary and sufficient to replicate all varieties of the sAPs recorded experimentally in DSMCs. This model has the potential to generate testable hypotheses that can help identify the physiological processes underlying various features of the sAPs. Further, this model also provides a means to classify the sAPs into various shape classes. PMID:29351282

A four-component model of the action potential in mouse detrusor smooth muscle cell.

PubMed

Padmakumar, Mithun; Brain, Keith L; Young, John S; Manchanda, Rohit

2018-01-01

Detrusor smooth muscle cells (DSMCs) of the urinary bladder are electrically connected to one another via gap junctions and form a three dimensional syncytium. DSMCs exhibit spontaneous electrical activity, including passive depolarizations and action potentials. The shapes of spontaneous action potentials (sAPs) observed from a single DSM cell can vary widely. The biophysical origins of this variability, and the precise components which contribute to the complex shapes observed are not known. To address these questions, the basic components which constitute the sAPs were investigated. We hypothesized that linear combinations of scaled versions of these basic components can produce sAP shapes observed in the syncytium. The basic components were identified as spontaneous evoked junction potentials (sEJP), native AP (nAP), slow after hyperpolarization (sAHP) and very slow after hyperpolarization (vsAHP). The experimental recordings were grouped into two sets: a training data set and a testing data set. A training set was used to estimate the components, and a test set to evaluate the efficiency of the estimated components. We found that a linear combination of the identified components when appropriately amplified and time shifted replicated various AP shapes to a high degree of similarity, as quantified by the root mean square error (RMSE) measure. We conclude that the four basic components-sEJP, nAP, sAHP, and vsAHP-identified and isolated in this work are necessary and sufficient to replicate all varieties of the sAPs recorded experimentally in DSMCs. This model has the potential to generate testable hypotheses that can help identify the physiological processes underlying various features of the sAPs. Further, this model also provides a means to classify the sAPs into various shape classes.

Soil respiration patterns in root gaps 27 years after small scale experimental disturbance in Pinus contorta forests

NASA Astrophysics Data System (ADS)

Baker, S.; Berryman, E.; Hawbaker, T. J.; Ewers, B. E.

2015-12-01

While much attention has been focused on large scale forest disturbances such as fire, harvesting, drought and insect attacks, small scale forest disturbances that create gaps in forest canopies and below ground root and mycorrhizal networks may accumulate to impact regional scale carbon budgets. In a lodgepole pine (Pinus contorta) forest near Fox Park, WY, clusters of 15 and 30 trees were removed in 1988 to assess the effect of tree gap disturbance on fine root density and nitrogen transformation. Twenty seven years later the gaps remain with limited regeneration present only in the center of the 30 tree plots, beyond the influence of roots from adjacent intact trees. Soil respiration was measured in the summer of 2015 to assess the influence of these disturbances on carbon cycling in Pinus contorta forests. Positions at the centers of experimental disturbances were found to have the lowest respiration rates (mean 2.45 μmol C/m2/s, standard error 0.17 C/m2/s), control plots in the undisturbed forest were highest (mean 4.15 μmol C/m2/s, standard error 0.63 C/m2/s), and positions near the margin of the disturbance were intermediate (mean 3.7 μmol C/m2/s, standard error 0.34 C/m2/s). Fine root densities, soil nitrogen, and microclimate changes were also measured and played an important role in respiration rates of disturbed plots. This demonstrates that a long-term effect on carbon cycling occurs when gaps are created in the canopy and root network of lodgepole forests.

Influence of surface error on electromagnetic performance of reflectors based on Zernike polynomials

NASA Astrophysics Data System (ADS)

Li, Tuanjie; Shi, Jiachen; Tang, Yaqiong

2018-04-01

This paper investigates the influence of surface error distribution on the electromagnetic performance of antennas. The normalized Zernike polynomials are used to describe a smooth and continuous deformation surface. Based on the geometrical optics and piecewise linear fitting method, the electrical performance of reflector described by the Zernike polynomials is derived to reveal the relationship between surface error distribution and electromagnetic performance. Then the relation database between surface figure and electric performance is built for ideal and deformed surfaces to realize rapidly calculation of far-field electric performances. The simulation analysis of the influence of Zernike polynomials on the electrical properties for the axis-symmetrical reflector with the axial mode helical antenna as feed is further conducted to verify the correctness of the proposed method. Finally, the influence rules of surface error distribution on electromagnetic performance are summarized. The simulation results show that some terms of Zernike polynomials may decrease the amplitude of main lobe of antenna pattern, and some may reduce the pointing accuracy. This work extracts a new concept for reflector's shape adjustment in manufacturing process.

Virtual gap element approach for the treatment of non-matching interface using three-dimensional solid elements

NASA Astrophysics Data System (ADS)

Song, Yeo-Ul; Youn, Sung-Kie; Park, K. C.

2017-10-01

A method for three-dimensional non-matching interface treatment with a virtual gap element is developed. When partitioned structures contain curved interfaces and have different brick meshes, the discretized models have gaps along the interfaces. As these gaps bring unexpected errors, special treatments are required to handle the gaps. In the present work, a virtual gap element is introduced to link the frame and surface domain nodes in the frame work of the mortar method. Since the surface of the hexahedron element is quadrilateral, the gap element is pyramidal. The pyramidal gap element consists of four domain nodes and one frame node. Zero-strain condition in the gap element is utilized for the interpolation of frame nodes in terms of the domain nodes. This approach is taken to satisfy the momentum and energy conservation. The present method is applicable not only to curved interfaces with gaps, but also to flat interfaces in three dimensions. Several numerical examples are given to describe the effectiveness and accuracy of the proposed method.

A-type potassium currents in smooth muscle.

PubMed

Amberg, Gregory C; Koh, Sang Don; Imaizumi, Yuji; Ohya, Susumu; Sanders, Kenton M

2003-03-01

A-type currents are voltage-gated, calcium-independent potassium (Kv) currents that undergo rapid activation and inactivation. Commonly associated with neuronal and cardiac cell-types, A-type currents have also been identified and characterized in vascular, genitourinary, and gastrointestinal smooth muscle cells. This review examines the molecular identity, biophysical properties, pharmacology, regulation, and physiological function of smooth muscle A-type currents. In general, this review is intended to facilitate the comparison of A-type currents present in different smooth muscles by providing a comprehensive report of the literature to date. This approach should also aid in the identification of areas of research requiring further attention.

Functional overestimation due to spatial smoothing of fMRI data.

PubMed

Liu, Peng; Calhoun, Vince; Chen, Zikuan

2017-11-01

Pearson correlation (simply correlation) is a basic technique for neuroimage function analysis. It has been observed that the spatial smoothing may cause functional overestimation, which however remains a lack of complete understanding. Herein, we present a theoretical explanation from the perspective of correlation scale invariance. For a task-evoked spatiotemporal functional dataset, we can extract the functional spatial map by calculating the temporal correlations (tcorr) of voxel timecourses against the task timecourse. From the relationship between image noise level (changed through spatial smoothing) and the tcorr map calculation, we show that the spatial smoothing causes a noise reduction, which in turn smooths the tcorr map and leads to a spatial expansion on neuroactivity blob estimation. Through numerical simulations and subject experiments, we show that the spatial smoothing of fMRI data may overestimate activation spots in the correlation functional map. Our results suggest a small spatial smoothing (with a smoothing kernel with a full width at half maximum (FWHM) of no more than two voxels) on fMRI data processing for correlation-based functional mapping COMPARISON WITH EXISTING METHODS: In extreme noiselessness, the correlation of scale-invariance property defines a meaningless binary tcorr map. In reality, a functional activity blob in a tcorr map is shaped due to the spoilage of image noise on correlative responses. We may reduce data noise level by smoothing processing, which poses a smoothing effect on correlation. This logic allows us to understand the noise dependence and the smoothing effect of correlation-based fMRI data analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Errors in causal inference: an organizational schema for systematic error and random error.

PubMed

Suzuki, Etsuji; Tsuda, Toshihide; Mitsuhashi, Toshiharu; Mansournia, Mohammad Ali; Yamamoto, Eiji

2016-11-01

To provide an organizational schema for systematic error and random error in estimating causal measures, aimed at clarifying the concept of errors from the perspective of causal inference. We propose to divide systematic error into structural error and analytic error. With regard to random error, our schema shows its four major sources: nondeterministic counterfactuals, sampling variability, a mechanism that generates exposure events and measurement variability. Structural error is defined from the perspective of counterfactual reasoning and divided into nonexchangeability bias (which comprises confounding bias and selection bias) and measurement bias. Directed acyclic graphs are useful to illustrate this kind of error. Nonexchangeability bias implies a lack of "exchangeability" between the selected exposed and unexposed groups. A lack of exchangeability is not a primary concern of measurement bias, justifying its separation from confounding bias and selection bias. Many forms of analytic errors result from the small-sample properties of the estimator used and vanish asymptotically. Analytic error also results from wrong (misspecified) statistical models and inappropriate statistical methods. Our organizational schema is helpful for understanding the relationship between systematic error and random error from a previously less investigated aspect, enabling us to better understand the relationship between accuracy, validity, and precision. Copyright © 2016 Elsevier Inc. All rights reserved.

Human error identification for laparoscopic surgery: Development of a motion economy perspective.

PubMed

Al-Hakim, Latif; Sevdalis, Nick; Maiping, Tanaphon; Watanachote, Damrongpan; Sengupta, Shomik; Dissaranan, Charuspong

2015-09-01

This study postulates that traditional human error identification techniques fail to consider motion economy principles and, accordingly, their applicability in operating theatres may be limited. This study addresses this gap in the literature with a dual aim. First, it identifies the principles of motion economy that suit the operative environment and second, it develops a new error mode taxonomy for human error identification techniques which recognises motion economy deficiencies affecting the performance of surgeons and predisposing them to errors. A total of 30 principles of motion economy were developed and categorised into five areas. A hierarchical task analysis was used to break down main tasks of a urological laparoscopic surgery (hand-assisted laparoscopic nephrectomy) to their elements and the new taxonomy was used to identify errors and their root causes resulting from violation of motion economy principles. The approach was prospectively tested in 12 observed laparoscopic surgeries performed by 5 experienced surgeons. A total of 86 errors were identified and linked to the motion economy deficiencies. Results indicate the developed methodology is promising. Our methodology allows error prevention in surgery and the developed set of motion economy principles could be useful for training surgeons on motion economy principles. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Production of super-smooth articles

DOEpatents

Duchane, David V.

1983-01-01

Super-smooth rounded or formed articles made of thermoplastic materials including various poly(methyl methacrylate) or acrylonitrile-butadiene-styrene copolymers are produced by immersing the articles into a bath, the composition of which is slowly changed with time. The starting composition of the bath is made up of at least one solvent for the polymer and a diluent made up of at least one nonsolvent for the polymer and optional materials which are soluble in the bath. The resulting extremely smooth articles are useful as mandrels for laser fusion and should be useful for a wide variety of other purposes, for example lenses.

Biometrics encryption combining palmprint with two-layer error correction codes

NASA Astrophysics Data System (ADS)

Li, Hengjian; Qiu, Jian; Dong, Jiwen; Feng, Guang

2017-07-01

To bridge the gap between the fuzziness of biometrics and the exactitude of cryptography, based on combining palmprint with two-layer error correction codes, a novel biometrics encryption method is proposed. Firstly, the randomly generated original keys are encoded by convolutional and cyclic two-layer coding. The first layer uses a convolution code to correct burst errors. The second layer uses cyclic code to correct random errors. Then, the palmprint features are extracted from the palmprint images. Next, they are fused together by XORing operation. The information is stored in a smart card. Finally, the original keys extraction process is the information in the smart card XOR the user's palmprint features and then decoded with convolutional and cyclic two-layer code. The experimental results and security analysis show that it can recover the original keys completely. The proposed method is more secure than a single password factor, and has higher accuracy than a single biometric factor.

Prostaglandins, oxygen tension and smooth muscle tone

PubMed Central

Eckenfels, A.; Vane, J. R.

1972-01-01

1. By using indomethacin to inhibit their intramural synthesis, we have investigated the contribution of prostaglandins to the maintenance of (a) the intrinsic tone of isolated smooth muscle preparations and (b) contractions produced by drugs or high oxygen concentration. 2. When treated with indomethacin, the rat stomach strip and chick rectum preparation slowly relaxed, whether they were bathed in Krebs solution or blood. Although their sensitivity to added prostaglandin was somewhat enhanced, they became insensitive to changes in oxygen or glucose concentration. However, another smooth muscle preparation, the rat colon, was neither relaxed by indomethacin nor contracted by high oxygen concentration. 3. These results support the hypothesis that intramural generation of prostaglandin maintains the tone of some smooth muscle preparations. 4. Contractions of the guinea-pig isolated colon were induced by histamine. These contractions were normally well maintained but in Krebs solution lacking either oxygen or glucose, only the initial spike contraction remained. In the presence of indomethacin the histamine contraction was also poorly sustained, but maintenance was restored by a low concentration of prostaglandin E2. 5. Thus, the effects on smooth muscle of oxygen or glucose lack may also be mediated by reduction in the synthesis or effects of an intramural prostaglandin. Extension of this hypothesis to intestinal and vascular smooth muscle in vivo is discussed. PMID:5072227

How Trainees Would Disclose Medical Errors: Educational Implications for Training Programs

PubMed Central

White, Andrew A.; Bell, Sigall K.; Krauss, Melissa J; Garbutt, Jane; Dunagan, W. Claiborne; Fraser, Victoria J.; Levinson, Wendy; Larson, Eric B.; Gallagher, Thomas H.

2012-01-01

Background Disclosing harmful errors to patients is recommended, but appears to be uncommon. Understanding how trainees disclose errors and how those practices evolve during training could help educators design programs to address this gap. Purpose To determine how trainees would disclose medical errors. Methods A survey of 758 trainees (488 students and 270 residents) in internal medicine at two academic medical centers. Surveys depicted one of two harmful error scenarios that varied by how apparent the error would be to the patient. We measured attitudes and disclosure content using scripted responses. Results Trainees reported their intent to disclose the error as “definitely” (43%) “probably” (47%) “only if asked by patient” (9%), and “definitely not” (1%). Trainees were more likely to disclose obvious errors in comparison with ones patients were unlikely to recognize (55% vs. 30%, P<0.01). Respondents varied widely in what information they would disclose. Fifty percent of trainees chose statements explicitly stating an error occurred rather than only an adverse event. Regarding apologies, trainees were split between a general expression of regret (52%) and an explicit apology (46%). Respondents at higher levels of training were less likely to use explicit apologies (Trend P<0.01). Prior disclosure training was associated with increased willingness to disclose errors (OR 1.40, P=0.03). Conclusions Trainees may not be prepared to disclose medical errors to patients, and worrisome trends in trainee apology practices were observed across levels of training. Medical educators should intensify efforts to enhance trainees’ skills at meeting patients’ expectations for open disclosure of harmful medical errors. PMID:21401685

Profound metabolic acidosis from pyroglutamic acidemia: an underappreciated cause of high anion gap metabolic acidosis.

PubMed

Green, Thomas J; Bijlsma, Jan Jaap; Sweet, David D

2010-09-01

The workup of the emergency patient with a raised anion gap metabolic acidosis includes assessment of the components of “MUDPILES” (methanol; uremia; diabetic ketoacidosis; paraldehyde; isoniazid, iron or inborn errors of metabolism; lactic acid; ethylene glycol; salicylates). This approach is usually sufficient for the majority of cases in the emergency department; however, there are many other etiologies not addressed in this mnemonic. Organic acids including 5-oxoproline (pyroglutamic acid) are rare but important causes of anion gap metabolic acidosis. We present the case of a patient with profound metabolic acidosis with raised anion gap, due to pyroglutamic acid in the setting of malnutrition and chronic ingestion of acetaminophen.

Effects of contrast on smooth pursuit eye movements.

PubMed

Spering, Miriam; Kerzel, Dirk; Braun, Doris I; Hawken, Michael J; Gegenfurtner, Karl R

2005-05-20

It is well known that moving stimuli can appear to move more slowly when contrast is reduced (P. Thompson, 1982). Here we address the question whether changes in stimulus contrast also affect smooth pursuit eye movements. Subjects were asked to smoothly track a moving Gabor patch. Targets varied in velocity (1, 8, and 15 deg/s), spatial frequency (0.1, 1, 4, and 8 c/deg), and contrast, ranging from just below individual thresholds to maximum contrast. Results show that smooth pursuit eye velocity gain rose significantly with increasing contrast. Below a contrast level of two to three times threshold, pursuit gain, acceleration, latency, and positional accuracy were severely impaired. Therefore, the smooth pursuit motor response shows the same kind of slowing at low contrast that was demonstrated in previous studies on perception.

A day in the life of a volunteer incident commander: errors, pressures and mitigating strategies.

PubMed

Bearman, Christopher; Bremner, Peter A

2013-05-01

To meet an identified gap in the literature this paper investigates the tasks that a volunteer incident commander needs to carry out during an incident, the errors that can be made and the way that errors are managed. In addition, pressure from goal seduction and situation aversion were also examined. Volunteer incident commanders participated in a two-part interview consisting of a critical decision method interview and discussions about a hierarchical task analysis constructed by the authors. A SHERPA analysis was conducted to further identify potential errors. The results identified the key tasks, errors with extreme risk, pressures from strong situations and mitigating strategies for errors and pressures. The errors and pressures provide a basic set of issues that need to be managed by both volunteer incident commanders and fire agencies. The mitigating strategies identified here suggest some ways that this can be done. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Mitochondrial motility and vascular smooth muscle proliferation.

PubMed

Chalmers, Susan; Saunter, Christopher; Wilson, Calum; Coats, Paul; Girkin, John M; McCarron, John G

2012-12-01

Mitochondria are widely described as being highly dynamic and adaptable organelles, and their movement is thought to be vital for cell function. Yet, in various native cells, including those of heart and smooth muscle, mitochondria are stationary and rigidly structured. The significance of the differences in mitochondrial behavior to the physiological function of cells is unclear and was studied in single myocytes and intact resistance-sized cerebral arteries. We hypothesized that mitochondrial dynamics is controlled by the proliferative status of the cells. High-speed fluorescence imaging of mitochondria in live vascular smooth muscle cells shows that the organelle undergoes significant reorganization as cells become proliferative. In nonproliferative cells, mitochondria are individual (≈ 2 μm by 0.5 μm), stationary, randomly dispersed, fixed structures. However, on entering the proliferative state, mitochondria take on a more diverse architecture and become small spheres, short rod-shaped structures, long filamentous entities, and networks. When cells proliferate, mitochondria also continuously move and change shape. In the intact pressurized resistance artery, mitochondria are largely immobile structures, except in a small number of cells in which motility occurred. When proliferation of smooth muscle was encouraged in the intact resistance artery, in organ culture, the majority of mitochondria became motile and the majority of smooth muscle cells contained moving mitochondria. Significantly, restriction of mitochondrial motility using the fission blocker mitochondrial division inhibitor prevented vascular smooth muscle proliferation in both single cells and the intact resistance artery. These results show that mitochondria are adaptable and exist in intact tissue as both stationary and highly dynamic entities. This mitochondrial plasticity is an essential mechanism for the development of smooth muscle proliferation and therefore presents a novel therapeutic

Beta-function B-spline smoothing on triangulations

NASA Astrophysics Data System (ADS)

Dechevsky, Lubomir T.; Zanaty, Peter

2013-03-01

In this work we investigate a novel family of Ck-smooth rational basis functions on triangulations for fitting, smoothing, and denoising geometric data. The introduced basis function is closely related to a recently introduced general method introduced in utilizing generalized expo-rational B-splines, which provides Ck-smooth convex resolutions of unity on very general disjoint partitions and overlapping covers of multidimensional domains with complex geometry. One of the major advantages of this new triangular construction is its locality with respect to the star-1 neighborhood of the vertex on which the said base is providing Hermite interpolation. This locality of the basis functions can be in turn utilized in adaptive methods, where, for instance a local refinement of the underlying triangular mesh affects only the refined domain, whereas, in other method one needs to investigate what changes are occurring outside of the refined domain. Both the triangular and the general smooth constructions have the potential to become a new versatile tool of Computer Aided Geometric Design (CAGD), Finite and Boundary Element Analysis (FEA/BEA) and Iso-geometric Analysis (IGA).

A smoothed two- and three-dimensional interface reconstruction method

DOE PAGES

Mosso, Stewart; Garasi, Christopher; Drake, Richard

2008-04-22

The Patterned Interface Reconstruction algorithm reduces the discontinuity between material interfaces in neighboring computational elements. This smoothing improves the accuracy of the reconstruction for smooth bodies. The method can be used in two- and three-dimensional Cartesian and unstructured meshes. Planar interfaces will be returned for planar volume fraction distributions. Finally, the algorithm is second-order accurate for smooth volume fraction distributions.

Children with ADHD Symptoms Are Less Susceptible to Gap-Filling Errors than Typically Developing Children

ERIC Educational Resources Information Center

Mirandola, C.; Paparella, G.; Re, A. M.; Ghetti, S.; Cornoldi, C.

2012-01-01

Enhanced semantic processing is associated with increased false recognition of items consistent with studied material, suggesting that children with poor semantic skills could produce fewer false memories. We examined whether memory errors differed in children with Attention Deficit/Hyperactivity Disorder (ADHD) and controls. Children viewed 18…

Mechanotransduction, asthma, and airway smooth muscle

PubMed Central

Fabry, Ben; Fredberg, Jeffrey J.

2008-01-01

Excessive force generation by airway smooth muscle is the main culprit in excessive airway narrowing during an asthma attack. The maximum force the airway smooth muscle can generate is exquisitely sensitive to muscle length fluctuations during breathing, and is governed by complex mechanotransduction events that can best be studied by a hybrid approach in which the airway wall is modeled in silico so as to set a dynamic muscle load comparable to that experienced in vivo. PMID:18836522

Disclosing Medical Errors to Patients: Attitudes and Practices of Physicians and Trainees

PubMed Central

Jones, Elizabeth W.; Wu, Barry J.; Forman-Hoffman, Valerie L.; Levi, Benjamin H.; Rosenthal, Gary E.

2007-01-01

BACKGROUND Disclosing errors to patients is an important part of patient care, but the prevalence of disclosure, and factors affecting it, are poorly understood. OBJECTIVE To survey physicians and trainees about their practices and attitudes regarding error disclosure to patients. DESIGN AND PARTICIPANTS Survey of faculty physicians, resident physicians, and medical students in Midwest, Mid-Atlantic, and Northeast regions of the United States. MEASUREMENTS Actual error disclosure; hypothetical error disclosure; attitudes toward disclosure; demographic factors. RESULTS Responses were received from 538 participants (response rate = 77%). Almost all faculty and residents responded that they would disclose a hypothetical error resulting in minor (97%) or major (93%) harm to a patient. However, only 41% of faculty and residents had disclosed an actual minor error (resulting in prolonged treatment or discomfort), and only 5% had disclosed an actual major error (resulting in disability or death). Moreover, 19% acknowledged not disclosing an actual minor error and 4% acknowledged not disclosing an actual major error. Experience with malpractice litigation was not associated with less actual or hypothetical error disclosure. Faculty were more likely than residents and students to disclose a hypothetical error and less concerned about possible negative consequences of disclosure. Several attitudes were associated with greater likelihood of hypothetical disclosure, including the belief that disclosure is right even if it comes at a significant personal cost. CONCLUSIONS There appears to be a gap between physicians’ attitudes and practices regarding error disclosure. Willingness to disclose errors was associated with higher training level and a variety of patient-centered attitudes, and it was not lessened by previous exposure to malpractice litigation. PMID:17473944

Aging may negatively impact movement smoothness during stair negotiation.

PubMed

Dixon, P C; Stirling, L; Xu, X; Chang, C C; Dennerlein, J T; Schiffman, J M

2018-05-26

Stairs represent a barrier to safe locomotion for some older adults, potentially leading to the adoption of a cautious gait strategy that may lack fluidity. This strategy may be characterized as unsmooth; however, stair negotiation smoothness has yet to be quantified. The aims of this study were to assess age- and task-related differences in head and body center of mass (COM) acceleration patterns and smoothness during stair negotiation and to determine if smoothness was associated with the timed "Up and Go" (TUG) test of functional movement. Motion data from nineteen older and twenty young adults performing stair ascent, stair descent, and overground straight walking trials were analyzed and used to compute smoothness based on the log-normalized dimensionless jerk (LDJ) and the velocity spectral arc length (SPARC) metrics. The associations between TUG and smoothness measures were evaluated using Pearson's correlation coefficient (r). Stair tasks increased head and body COM acceleration pattern differences across groups, compared to walking (p < 0.05). LDJ smoothness for the head and body COM decreased in older adults during stair descent, compared to young adults (p ≤ 0.015) and worsened with increasing TUG for all tasks (-0.60 ≤ r ≤ -0.43). SPARC smoothness of the head and body COM increased in older adults, regardless of task (p < 0.001), while correlations showed improved SPARC smoothness with increasing TUG for some tasks (0.33 ≤ r ≤ 0.40). The LDJ outperforms SPARC in identifying age-related stair negotiation adaptations and is associated with performance on a clinical test of gait. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of gap detection threshold on consistency of speech in children with speech sound disorder.

PubMed

Sayyahi, Fateme; Soleymani, Zahra; Akbari, Mohammad; Bijankhan, Mahmood; Dolatshahi, Behrooz

2017-02-01

The present study examined the relationship between gap detection threshold and speech error consistency in children with speech sound disorder. The participants were children five to six years of age who were categorized into three groups of typical speech, consistent speech disorder (CSD) and inconsistent speech disorder (ISD).The phonetic gap detection threshold test was used for this study, which is a valid test comprised six syllables with inter-stimulus intervals between 20-300ms. The participants were asked to listen to the recorded stimuli three times and indicate whether they heard one or two sounds. There was no significant difference between the typical and CSD groups (p=0.55), but there were significant differences in performance between the ISD and CSD groups and the ISD and typical groups (p=0.00). The ISD group discriminated between speech sounds at a higher threshold. Children with inconsistent speech errors could not distinguish speech sounds during time-limited phonetic discrimination. It is suggested that inconsistency in speech is a representation of inconsistency in auditory perception, which causes by high gap detection threshold. Copyright © 2016 Elsevier Ltd. All rights reserved.

Vardenafil inhibiting parasympathetic function of tracheal smooth muscle.

PubMed

Lee, Fei-Peng; Chao, Pin-Zhir; Wang, Hsing-Won

2018-07-01

Levitra, a phosphodiesterase-5 (PDE5) inhibitor, is the trade name of vardenafil. Nowadays, it is applied to treatment of erectile dysfunction. PDE5 inhibitors are employed to induce dilatation of the vascular smooth muscle. The effect of Levitra on impotency is well known; however, its effect on the tracheal smooth muscle has rarely been explored. When administered for sexual symptoms via oral intake or inhalation, Levitra might affect the trachea. This study assessed the effects of Levitra on isolated rat tracheal smooth muscle by examining its effect on resting tension of tracheal smooth muscle, contraction caused by 10 -6  M methacholine as a parasympathetic mimetic, and electrically induced tracheal smooth muscle contractions. The results showed that adding methacholine to the incubation medium caused the trachea to contract in a dose-dependent manner. Addition of Levitra at doses of 10 -5  M or above elicited a significant relaxation response to 10 -6  M methacholine-induced contraction. Levitra could inhibit electrical field stimulation-induced spike contraction. It alone had minimal effect on the basal tension of the trachea as the concentration increased. High concentrations of Levitra could inhibit parasympathetic function of the trachea. Levitra when administered via oral intake might reduce asthma attacks in impotent patients because it might inhibit parasympathetic function and reduce methacholine-induced contraction of the tracheal smooth muscle. Copyright © 2018. Published by Elsevier Taiwan LLC.

s-SMOOTH: Sparsity and Smoothness Enhanced EEG Brain Tomography

PubMed Central

Li, Ying; Qin, Jing; Hsin, Yue-Loong; Osher, Stanley; Liu, Wentai

2016-01-01

EEG source imaging enables us to reconstruct current density in the brain from the electrical measurements with excellent temporal resolution (~ ms). The corresponding EEG inverse problem is an ill-posed one that has infinitely many solutions. This is due to the fact that the number of EEG sensors is usually much smaller than that of the potential dipole locations, as well as noise contamination in the recorded signals. To obtain a unique solution, regularizations can be incorporated to impose additional constraints on the solution. An appropriate choice of regularization is critically important for the reconstruction accuracy of a brain image. In this paper, we propose a novel Sparsity and SMOOthness enhanced brain TomograpHy (s-SMOOTH) method to improve the reconstruction accuracy by integrating two recently proposed regularization techniques: Total Generalized Variation (TGV) regularization and ℓ1−2 regularization. TGV is able to preserve the source edge and recover the spatial distribution of the source intensity with high accuracy. Compared to the relevant total variation (TV) regularization, TGV enhances the smoothness of the image and reduces staircasing artifacts. The traditional TGV defined on a 2D image has been widely used in the image processing field. In order to handle 3D EEG source images, we propose a voxel-based Total Generalized Variation (vTGV) regularization that extends the definition of second-order TGV from 2D planar images to 3D irregular surfaces such as cortex surface. In addition, the ℓ1−2 regularization is utilized to promote sparsity on the current density itself. We demonstrate that ℓ1−2 regularization is able to enhance sparsity and accelerate computations than ℓ1 regularization. The proposed model is solved by an efficient and robust algorithm based on the difference of convex functions algorithm (DCA) and the alternating direction method of multipliers (ADMM). Numerical experiments using synthetic data demonstrate the

A meta-analytic review of two modes of learning and the description-experience gap.

PubMed

Wulff, Dirk U; Mergenthaler-Canseco, Max; Hertwig, Ralph

2018-02-01

People can learn about the probabilistic consequences of their actions in two ways: One is by consulting descriptions of an action's consequences and probabilities (e.g., reading up on a medication's side effects). The other is by personally experiencing the probabilistic consequences of an action (e.g., beta testing software). In principle, people taking each route can reach analogous states of knowledge and consequently make analogous decisions. In the last dozen years, however, research has demonstrated systematic discrepancies between description- and experienced-based choices. This description-experience gap has been attributed to factors including reliance on a small set of experience, the impact of recency, and different weighting of probability information in the two decision types. In this meta-analysis focusing on studies using the sampling paradigm of decisions from experience, we evaluated these and other determinants of the decision-experience gap by reference to more than 70,000 choices made by more than 6,000 participants. We found, first, a robust description-experience gap but also a key moderator, namely, problem structure. Second, the largest determinant of the gap was reliance on small samples and the associated sampling error: free to terminate search, individuals explored too little to experience all possible outcomes. Third, the gap persisted when sampling error was basically eliminated, suggesting other determinants. Fourth, the occurrence of recency was contingent on decision makers' autonomy to terminate search, consistent with the notion of optional stopping. Finally, we found indications of different probability weighting in decisions from experience versus decisions from description when the problem structure involved a risky and a safe option. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Mechanisms of Vascular Smooth Muscle Contraction and the Basis for Pharmacologic Treatment of Smooth Muscle Disorders

PubMed Central

Brozovich, F.V.; Nicholson, C.J.; Degen, C.V.; Gao, Yuan Z.; Aggarwal, M.

2016-01-01

The smooth muscle cell directly drives the contraction of the vascular wall and hence regulates the size of the blood vessel lumen. We review here the current understanding of the molecular mechanisms by which agonists, therapeutics, and diseases regulate contractility of the vascular smooth muscle cell and we place this within the context of whole body function. We also discuss the implications for personalized medicine and highlight specific potential target molecules that may provide opportunities for the future development of new therapeutics to regulate vascular function. PMID:27037223

A procedure for removing the effect of response bias errors from waterfowl hunter questionnaire responses

USGS Publications Warehouse

Atwood, E.L.

1958-01-01

Response bias errors are studied by comparing questionnaire responses from waterfowl hunters using four large public hunting areas with actual hunting data from these areas during two hunting seasons. To the extent that the data permit, the sources of the error in the responses were studied and the contribution of each type to the total error was measured. Response bias errors, including both prestige and memory bias, were found to be very large as compared to non-response and sampling errors. Good fits were obtained with the seasonal kill distribution of the actual hunting data and the negative binomial distribution and a good fit was obtained with the distribution of total season hunting activity and the semi-logarithmic curve. A comparison of the actual seasonal distributions with the questionnaire response distributions revealed that the prestige and memory bias errors are both positive. The comparisons also revealed the tendency for memory bias errors to occur at digit frequencies divisible by five and for prestige bias errors to occur at frequencies which are multiples of the legal daily bag limit. A graphical adjustment of the response distributions was carried out by developing a smooth curve from those frequency classes not included in the predictable biased frequency classes referred to above. Group averages were used in constructing the curve, as suggested by Ezekiel [1950]. The efficiency of the technique described for reducing response bias errors in hunter questionnaire responses on seasonal waterfowl kill is high in large samples. The graphical method is not as efficient in removing response bias errors in hunter questionnaire responses on seasonal hunting activity where an average of 60 percent was removed.

Interprofessional communication and medical error: a reframing of research questions and approaches.

PubMed

Varpio, Lara; Hall, Pippa; Lingard, Lorelei; Schryer, Catherine F

2008-10-01

Progress toward understanding the links between interprofessional communication and issues of medical error has been slow. Recent research proposes that this delay may result from overlooking the complexities involved in interprofessional care. Medical education initiatives in this domain tend to simplify the complexities of team membership fluidity, rotation, and use of communication tools. A new theoretically informed research approach is required to take into account these complexities. To generate such an approach, we review two theories from the social sciences: Activity Theory and Knotworking. Using these perspectives, we propose that research into interprofessional communication and medical error can develop better understandings of (1) how and why medical errors are generated and (2) how and why gaps in team defenses occur. Such complexities will have to be investigated if students and practicing clinicians are to be adequately prepared to work safely in interprofessional teams.

Forecasting Inflow and Outflow of Money Currency in East Java Using a Hybrid Exponential Smoothing and Calendar Variation Model

NASA Astrophysics Data System (ADS)

Susanti, Ana; Suhartono; Jati Setyadi, Hario; Taruk, Medi; Haviluddin; Pamilih Widagdo, Putut

2018-03-01

Money currency availability in Bank Indonesia can be examined by inflow and outflow of money currency. The objective of this research is to forecast the inflow and outflow of money currency in each Representative Office (RO) of BI in East Java by using a hybrid exponential smoothing based on state space approach and calendar variation model. Hybrid model is expected to generate more accurate forecast. There are two studies that will be discussed in this research. The first studies about hybrid model using simulation data that contain pattern of trends, seasonal and calendar variation. The second studies about the application of a hybrid model for forecasting the inflow and outflow of money currency in each RO of BI in East Java. The first of results indicate that exponential smoothing model can not capture the pattern calendar variation. It results RMSE values 10 times standard deviation of error. The second of results indicate that hybrid model can capture the pattern of trends, seasonal and calendar variation. It results RMSE values approaching the standard deviation of error. In the applied study, the hybrid model give more accurate forecast for five variables : the inflow of money currency in Surabaya, Malang, Jember and outflow of money currency in Surabaya and Kediri. Otherwise, the time series regression model yields better for three variables : outflow of money currency in Malang, Jember and inflow of money currency in Kediri.

An improved GRACE monthly gravity field solution by modeling the non-conservative acceleration and attitude observation errors

NASA Astrophysics Data System (ADS)

Chen, Qiujie; Shen, Yunzhong; Chen, Wu; Zhang, Xingfu; Hsu, Houze

2016-06-01

The main contribution of this study is to improve the GRACE gravity field solution by taking errors of non-conservative acceleration and attitude observations into account. Unlike previous studies, the errors of the attitude and non-conservative acceleration data, and gravity field parameters, as well as accelerometer biases are estimated by means of weighted least squares adjustment. Then we compute a new time series of monthly gravity field models complete to degree and order 60 covering the period Jan. 2003 to Dec. 2012 from the twin GRACE satellites' data. The derived GRACE solution (called Tongji-GRACE02) is compared in terms of geoid degree variances and temporal mass changes with the other GRACE solutions, namely CSR RL05, GFZ RL05a, and JPL RL05. The results show that (1) the global mass signals of Tongji-GRACE02 are generally consistent with those of CSR RL05, GFZ RL05a, and JPL RL05; (2) compared to CSR RL05, the noise of Tongji-GRACE02 is reduced by about 21 % over ocean when only using 300 km Gaussian smoothing, and 60 % or more over deserts (Australia, Kalahari, Karakum and Thar) without using Gaussian smoothing and decorrelation filtering; and (3) for all examples, the noise reductions are more significant than signal reductions, no matter whether smoothing and filtering are applied or not. The comparison with GLDAS data supports that the signals of Tongji-GRACE02 over St. Lawrence River basin are close to those from CSR RL05, GFZ RL05a and JPL RL05, while the GLDAS result shows the best agreement with the Tongji-GRACE02 result.

Disturbance of smooth muscle regulatory function by Eisenia foetida toxin lysenin: insight into the mechanism of smooth muscle contraction.

PubMed

Czuryło, Edward A; Kulikova, Natalia; Sobota, Andrzej

2008-05-01

Lysenin, a toxin present in the coelomic fluid of the earthworm Eisenia foetida, is known to cause a long-lasting contraction of rat aorta smooth muscle strips. We addressed the mechanisms underlying its action on smooth muscle cells and present the first report demonstrating a completely new property of lysenin unrelated to its basic sphingomyelin-binding ability. Here we report lysenin enhancement effect on smooth muscle actomyosin ATPase activity and the ability of networking the actin filaments. The maximum enhancement of the ATPase activity of actomyosin at 120 mM KCl was observed at a molar ratio of lysenin to actin of about 1:10(5), while at 70 mM KCl at the ratio of about 1:10(6). The effect of lysenin became most pronounced only when both smooth muscle regulatory proteins, tropomyosin and caldesmon, were present. Co-sedimentation experiments indicated that lysenin did not displace neither tropomyosin nor caldesmon from the thin filament. Thus, the lysenin-dependent abolishment of the inhibitory effect of caldesmon on the ATPase activity was related rather to the modification of the filament structure. The ability of the toxin to exert its stimulatory effect at extremely low concentrations (as low as one molecule of lysenin per 10(6) actin molecules) may result from the long-range cooperative transitions in the entire thin filament with an involvement of smooth muscle tropomyosin, while the role of caldesmon may be limited exclusively to the inhibition of ATPase activity.

Further investigations on fixed abrasive diamond pellets used for diminishing mid-spatial frequency errors of optical mirrors.

PubMed

Dong, Zhichao; Cheng, Haobo; Tam, Hon-Yuen

2014-01-20

As further application investigations on fixed abrasive diamond pellets (FADPs), this work exhibits their potential capability for diminishing mid-spatial frequency errors (MSFEs, i.e., periodic small structure) of optical surfaces. Benefitting from its high surficial rigidness, the FADPs tool has a natural smoothing effect to periodic small errors. Compared with the previous design, this proposed new tool employs more compliance to aspherical surfaces due to the pellets being mutually separated and bonded on a steel plate with elastic back of silica rubber adhesive. Moreover, a unicursal Peano-like path is presented for improving MSFEs, which can enhance the multidirectionality and uniformity of the tool's motion. Experiments were conducted to validate the effectiveness of FADPs for diminishing MSFEs. In the lapping of a Φ=420 mm Zerodur paraboloid workpiece, the grinding ripples were quickly diminished (210 min) by both visual inspection and profile metrology, as well as the power spectrum density (PSD) analysis, RMS was reduced from 4.35 to 0.55 μm. In the smoothing of a Φ=101 mm fused silica workpiece, MSFEs were obviously improved from the inspection of surface form maps, interferometric fringe patterns, and PSD analysis. The mid-spatial frequency RMS was diminished from 0.017λ to 0.014λ (λ=632.8 nm).

Multi-PON access network using a coarse AWG for smooth migration from TDM to WDM PON

NASA Astrophysics Data System (ADS)

Shachaf, Y.; Chang, C.-H.; Kourtessis, P.; Senior, J. M.

2007-06-01

An interoperable access network architecture based on a coarse array waveguide grating (AWG) is described, displaying dynamic wavelength assignment to manage the network load across multiple PONs. The multi-PON architecture utilizes coarse Gaussian channels of an AWG to facilitate scalability and smooth migration path between TDM and WDM PONs. Network simulations of a cross-operational protocol platform confirmed successful routing of individual PON clusters through 7 nm-wide passband windows of the AWG. Furthermore, polarization-dependent wavelength shift and phase errors of the device proved not to impose restrain on the routing performance. Optical transmission tests at 2.5 Gbit/s for distances up to 20 km are demonstrated.

Outbreak Column 16: Cognitive errors in outbreak decision making.

PubMed

Curran, Evonne T

2015-01-01

During outbreaks, decisions must be made without all the required information. People, including infection prevention and control teams (IPCTs), who have to make decisions during uncertainty use heuristics to fill the missing data gaps. Heuristics are mental model short cuts that by-and-large enable us to make good decisions quickly. However, these heuristics contain biases and effects that at times lead to cognitive (thinking) errors. These cognitive errors are not made to deliberately misrepresent any given situation; we are subject to heuristic biases when we are trying to perform optimally. The science of decision making is large; there are over 100 different biases recognised and described. Outbreak Column 16 discusses and relates these heuristics and biases to decision making during outbreak prevention, preparedness and management. Insights as to how we might recognise and avoid them are offered.

Error begat error: design error analysis and prevention in social infrastructure projects.

PubMed

Love, Peter E D; Lopez, Robert; Edwards, David J; Goh, Yang M

2012-09-01

Design errors contribute significantly to cost and schedule growth in social infrastructure projects and to engineering failures, which can result in accidents and loss of life. Despite considerable research that has addressed their error causation in construction projects they still remain prevalent. This paper identifies the underlying conditions that contribute to design errors in social infrastructure projects (e.g. hospitals, education, law and order type buildings). A systemic model of error causation is propagated and subsequently used to develop a learning framework for design error prevention. The research suggests that a multitude of strategies should be adopted in congruence to prevent design errors from occurring and so ensure that safety and project performance are ameliorated. Copyright © 2011. Published by Elsevier Ltd.

The Limits of Coding with Joint Constraints on Detected and Undetected Error Rates

NASA Technical Reports Server (NTRS)

Dolinar, Sam; Andrews, Kenneth; Pollara, Fabrizio; Divsalar, Dariush

2008-01-01

We develop a remarkably tight upper bound on the performance of a parameterized family of bounded angle maximum-likelihood (BA-ML) incomplete decoders. The new bound for this class of incomplete decoders is calculated from the code's weight enumerator, and is an extension of Poltyrev-type bounds developed for complete ML decoders. This bound can also be applied to bound the average performance of random code ensembles in terms of an ensemble average weight enumerator. We also formulate conditions defining a parameterized family of optimal incomplete decoders, defined to minimize both the total codeword error probability and the undetected error probability for any fixed capability of the decoder to detect errors. We illustrate the gap between optimal and BA-ML incomplete decoding via simulation of a small code.

Smoothing Polymer Surfaces by Solvent-Vapor Exposure

NASA Astrophysics Data System (ADS)

Anthamatten, Mitchell

2003-03-01

Ultra-smooth polymer surfaces are of great importance in a large body of technical applications such as optical coatings, supermirrors, waveguides, paints, and fusion targets. We are investigating a simple approach to controlling surface roughness: by temporarily swelling the polymer with solvent molecules. As the solvent penetrates into the polymer, its viscosity is lowered, and surface tension forces drive surface flattening. To investigate sorption kinetics and surface-smoothing phenomena, a series of vapor-deposited poly(amic acid) films were exposed to dimethyl sulfoxide vapors. During solvent exposure, the surface topology was continuously monitored using light interference microscopy. The resulting power spectra indicate that high-frequency defects smooth faster than low-frequency defects. This frequency dependence was studied by depositing polymer films onto a series of 2D sinusoidal surfaces and performing smoothing experiments. Results show that the amplitudes of the sinusoidal surfaces decay exponentially with solvent exposure time, and the exponential decay constants are proportional to surface frequency. This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Stimulation of aortic smooth muscle cell mitogenesis by serotonin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nemecek, G.M.; Coughlin, S.R.; Handley, D.A.

1986-02-01

Bovine aortic smooth muscle cells in vitro responded to 1 nM to 10 ..mu..M serotonin with increased incorporation of (/sup 3/H)thymidine into DNA. The mitogenic effect of serotonin was half-maximal at 80 nM and maximal above 1 ..mu..M. At a concentration of 1 ..mu..M, serotonin stimulated smooth muscle cell mitogenesis to the same extent as human platelet-derived growth factor (PDGF) at 12 ng/ml. Tryptamine was approx. = 1/10th as potent as serotonin as a mitogen for smooth muscle cells. Other indoles that are structurally related to serotonin (D- and L-tryptophan, 5-hydroxy-L-tryptophan, N-acetyl-5-hydroxytryptamine, melatonin, 5-hydroxyindoleacetic acid, and 5-hydroxytryptophol) and quipazine weremore » inactive. The stimulatory effect of serotonin on smooth muscle cell DNA synthesis required prolonged (20-24 hr) exposure to the agonist and was attenuated in the presence of serotonin D receptor antagonists. When smooth muscle cells were incubated with submaximal concentrations of serotonin and PDGF, synergistic rather than additive mitogenic responses were observed. These data indicate that serotonin has a significant mitogenic effect on smooth muscle cells in vitro, which appears to be mediated by specific plasma membrane receptors.« less

Optical smoothing of laser imprinting in planar-target experiments on OMEGA EP using multi-FM 1-D smoothing by spectral dispersion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hohenberger, M., E-mail: mhoh@lle.rochester.edu; Shvydky, A.; Marozas, J. A.

Direct-drive ignition on the National Ignition Facility (NIF) requires single-beam smoothing to minimize imprinting of laser nonuniformities that can negatively affect implosion performance. One-dimensional, multi-FM smoothing by spectral dispersion (SSD) has been proposed to provide the required smoothing [Marozas et al., Bull. Am. Phys. Soc. 55, 294 (2010)]. A prototype multi-FM SSD system has been integrated into the NIF-like beamline of the OMEGA EP Laser System. Experiments have been performed to verify the smoothing performance by measuring Rayleigh–Taylor growth rates in planar targets of laser-imprinted and preimposed surface modulations. Multi-FM 1-D SSD has been observed to reduce imprint levels bymore » ∼50% compared to the nominal OMEGA EP SSD system. The experimental results are in agreement with 2-D DRACO simulations using realistic, time-dependent far-field spot-intensity calculations that emulate the effect of SSD.« less

Quasiparticle band gap in the topological insulator Bi2Te3

NASA Astrophysics Data System (ADS)

Nechaev, I. A.; Chulkov, E. V.

2013-10-01

We present a theoretical study of dispersion of states that form the bulk band-gap edges in the three-dimensional topological insulator Bi2Te3. Within density functional theory, we analyze the effect of atomic positions varied within the error range of the available experimental data and approximation chosen for the exchange-correlation functional on the bulk band gap and k-space location of valence- and conduction-band extrema. For each set of the positions with different exchange-correlation functionals, we show how many-body corrections calculated within a one-shot GW approach affect the mentioned characteristics of electronic structure of Bi2Te3. We thus also illustrate to what degree the one-shot GW results are sensitive to the reference one-particle band structure in the case of bismuth telluride. We found that for this topological insulator the GW corrections enlarge the fundamental band gap and for certain atomic positions and reference band structure bring its value in close agreement with experiment.

Interacting multiple model forward filtering and backward smoothing for maneuvering target tracking

NASA Astrophysics Data System (ADS)

Nandakumaran, N.; Sutharsan, S.; Tharmarasa, R.; Lang, Tom; McDonald, Mike; Kirubarajan, T.

2009-08-01

The Interacting Multiple Model (IMM) estimator has been proven to be effective in tracking agile targets. Smoothing or retrodiction, which uses measurements beyond the current estimation time, provides better estimates of target states. Various methods have been proposed for multiple model smoothing in the literature. In this paper, a new smoothing method, which involves forward filtering followed by backward smoothing while maintaining the fundamental spirit of the IMM, is proposed. The forward filtering is performed using the standard IMM recursion, while the backward smoothing is performed using a novel interacting smoothing recursion. This backward recursion mimics the IMM estimator in the backward direction, where each mode conditioned smoother uses standard Kalman smoothing recursion. Resulting algorithm provides improved but delayed estimates of target states. Simulation studies are performed to demonstrate the improved performance with a maneuvering target scenario. The comparison with existing methods confirms the improved smoothing accuracy. This improvement results from avoiding the augmented state vector used by other algorithms. In addition, the new technique to account for model switching in smoothing is a key in improving the performance.

The effect of robot dynamics on smoothness during wrist pointing.

PubMed

Erwin, Andrew; Pezent, Evan; Bradley, Joshua; O'Malley, Marcia K

2017-07-01

The improvement of movement smoothness over the course of therapy is one of the positive outcomes observed during robotic rehabilitation. Although movements are generally robust to disturbances, certain perturbations might disrupt an individual's ability to produce these smooth movements. In this paper, we explore how a rehabilitation robot's inherent dynamics impact movement smoothness during pointing tasks. Able-bodied participants made wrist pointing movements under four different operating conditions. Despite the relative transparency of the device, inherent dynamic characteristics negatively impacted movement smoothness. Active compensation for Coulomb friction effects failed to mitigate the degradation in smoothness. Assessment of movements that involved coupled motions of the robot's joints reduced the bias seen in single degree of freedom movements. When using robotic devices for assessment of movement quality, the impact of the inherent dynamics must be considered.

GAP/CL-20-Based Compound Explosive: A New Booster Formulation Used in a Small-Sized Initiation Network

NASA Astrophysics Data System (ADS)

Yanju, Wei; Jingyu, Wang; Chongwei, An; Hequn, Li; Xiaomu, Wen; Binshuo, Yu

2017-01-01

With ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and glycidyl azide polymer (GAP) as the solid filler and binder, respectively, GAP/CL-20-based compound explosives were designed and prepared. Using micro injection charge technology, the compound explosives were packed into small grooves to explore their application in a small-sized initiation network. The detonation reliability, detonation velocity, mechanical sensitivity, shock sensitivity, and brisance of the explosive were measured and analyzed. The results show that when the solid content of CL-20 is 82 wt%, the explosive charged in the groove has a smooth surface from a macroscopic view. From a microscopic view, a coarse surface is bonded with many CL-20 particles by GAP binder. The GAP/CL-20-based explosive charge successfully generates detonation waves in a groove larger than 0.6 mm × 0.6 mm. When the charge density in the groove is 1.68 g.cm-3 (90% theoretical maximum density), the detonation velocity reaches 7,290 m.s-1. Moreover, this kind of explosive is characterized by low impact and shock sensitivity.

Studies of the Wetting of Gaps in Weightlessness

NASA Astrophysics Data System (ADS)

Collicott, Steven H.; Chen, Yongkang

2010-10-01

The geometry of a thin sheet metal vane terminating near a wall in a surface tension propellant management device (PMD) is common in devices designed by various people. A research program into the capillary fluid physics of the common vane-wall gap began in 1998 with the arrival of the second author at the School of Aeronautics and Astronautics at Purdue University. Drop tower experiments, Surface Evolver computations, and analysis were combined to explore the details of the fluid behavior in the vane-wall gap geometry. Results of four vane-wall gap experiment topics: critical wetting, advance rates, sensitivity to vane orientation, and effect of imperfect initial conditions, are discussed here. This work led to a desire by Weislogel to incorporate this type of geometry into his "Capillary Fluids Experiment" (CFE) that operated flawlessly on the International Space Station in 2006 and 2007. It is found that the wetting of vane-wall gaps is predicted correctly through use of the critical wetting analysis of Concus and Finn. Furthermore, the dynamics of the wetting flows are found to have scaling of flow rates versus time similar to those known for capillary advances in solid corners. In some cases, a seemingly misaligned vane is found to have more rapid capillary advance than for the same vane and gap but with the vane normal to the tank wall. An initial drop tower study of sensitivity to imperfect initial conditions shows that a critical wetting flow is largely immune to small tilts in the initial test orientation but that larger errors can be seen in cases that lack critical wetting and in the measurements of the time history of the meniscus minimum point.

Quantum error suppression with commuting Hamiltonians: two local is too local.

PubMed

Marvian, Iman; Lidar, Daniel A

2014-12-31

We consider error suppression schemes in which quantum information is encoded into the ground subspace of a Hamiltonian comprising a sum of commuting terms. Since such Hamiltonians are gapped, they are considered natural candidates for protection of quantum information and topological or adiabatic quantum computation. However, we prove that they cannot be used to this end in the two-local case. By making the favorable assumption that the gap is infinite, we show that single-site perturbations can generate a degeneracy splitting in the ground subspace of this type of Hamiltonian which is of the same order as the magnitude of the perturbation, and is independent of the number of interacting sites and their Hilbert space dimensions, just as in the absence of the protecting Hamiltonian. This splitting results in decoherence of the ground subspace, and we demonstrate that for natural noise models the coherence time is proportional to the inverse of the degeneracy splitting. Our proof involves a new version of the no-hiding theorem which shows that quantum information cannot be approximately hidden in the correlations between two quantum systems. The main reason that two-local commuting Hamiltonians cannot be used for quantum error suppression is that their ground subspaces have only short-range (two-body) entanglement.

Smoothed-particle hydrodynamics and nonequilibrium molecular dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoover, W. G.; Hoover, C. G.

1993-08-01

Gingold, Lucy, and Monaghan invented a grid-free version of continuum mechanics ``smoothed-particle hydrodynamics,`` in 1977. It is a likely contributor to ``hybrid`` simulations combining atomistic and continuum simulations. We describe applications of this particle-based continuum technique from the closely-related standpoint of nonequilibrium molecular dynamics. We compare chaotic Lyapunov spectra for atomistic solids and fluids with those which characterize a two-dimensional smoothed-particle fluid system.

Optical smoothing of laser imprinting in planar-target experiments on OMEGA EP using multi-FM 1-D smoothing by spectral dispersion

DOE PAGES

Hohenberger, M.; Shvydky, A.; Marozas, J. A.; ...

2016-09-07

Direct-drive ignition on the National Ignition Facility (NIF) requires single-beam smoothing to minimize imprinting of laser nonuniformities that can negatively affect implosion performance. One-dimensional, multi-FM smoothing by spectral dispersion (SSD) has been proposed to provide the required smoothing [J. A. Marozas, J. D. Zuegel, and T. J. B. Collins, Bull. Am. Phys. Soc. 55, 294 (2010)]. A prototype multi-FM SSD system has been integrated into the NIF-like beamline of the OMEGA EP Laser System. Experiments have been performed to verify the smoothing performance by measuring Rayleigh–Taylor growth rates in planar targets of laser-imprinted and preimposed surface modulations. Multi-FM 1-D SSDmore » has been observed to reduce imprint levels by ~50% compared to the nominal OMEGA EP SSD system. In conclusion, the experimental results are in agreement with 2-D DRACO simulations using realistic, time-dependent far-field spot-intensity calculations that emulate the effect of SSD.« less

Optical smoothing of laser imprinting in planar-target experiments on OMEGA EP using multi-FM 1-D smoothing by spectral dispersion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hohenberger, M.; Shvydky, A.; Marozas, J. A.

Direct-drive ignition on the National Ignition Facility (NIF) requires single-beam smoothing to minimize imprinting of laser nonuniformities that can negatively affect implosion performance. One-dimensional, multi-FM smoothing by spectral dispersion (SSD) has been proposed to provide the required smoothing [J. A. Marozas, J. D. Zuegel, and T. J. B. Collins, Bull. Am. Phys. Soc. 55, 294 (2010)]. A prototype multi-FM SSD system has been integrated into the NIF-like beamline of the OMEGA EP Laser System. Experiments have been performed to verify the smoothing performance by measuring Rayleigh–Taylor growth rates in planar targets of laser-imprinted and preimposed surface modulations. Multi-FM 1-D SSDmore » has been observed to reduce imprint levels by ~50% compared to the nominal OMEGA EP SSD system. In conclusion, the experimental results are in agreement with 2-D DRACO simulations using realistic, time-dependent far-field spot-intensity calculations that emulate the effect of SSD.« less

Spatial perseveration error by alpacas (Vicugna pacos) in an A-not-B detour task.

PubMed

Abramson, José Z; Paulina Soto, D; Beatriz Zapata, S; Lloreda, María Victoria Hernández

2018-05-01

Spatial perseveration has been documented for domestic animals such as mules, donkeys, horses and dogs. However, evidence for this spatial cognition behavior among other domestic species is scarce. Alpacas have been domesticated for at least 7000 years yet their cognitive ability has not been officially reported. The present article used an A-not-B detour task to study the spatial problem-solving abilities of alpacas (Vicugna pacos) and to identify the perseveration errors, which refers to a tendency to maintain a learned route, despite having another available path. The study tested 51 alpacas, which had to pass through a gap at one end of a barrier in order to reach a reward. After one, two, three or four repeats (A trials), the gap was moved to the opposite end of the barrier (B trials). In contrast to what has been found in other domestic animals tested with the same task, the present study did not find clear evidence of spatial perseveration. Individuals' performance in the subsequent B trials, following the change of gap location, suggests no error persistence in alpacas. Results suggest that alpacas are more flexible than other domestic animals tested with this same task, which has important implications in planning proper training for experimental designs or productive purposes. These results could contribute toward enhancing alpacas' welfare and our understanding of their cognitive abilities.

Ureter smooth muscle cell orientation in rat is predominantly longitudinal.

PubMed

Spronck, Bart; Merken, Jort J; Reesink, Koen D; Kroon, Wilco; Delhaas, Tammo

2014-01-01

In ureter peristalsis, the orientation of the contracting smooth muscle cells is essential, yet current descriptions of orientation and composition of the smooth muscle layer in human as well as in rat ureter are inconsistent. The present study aims to improve quantification of smooth muscle orientation in rat ureters as a basis for mechanistic understanding of peristalsis. A crucial step in our approach is to use two-photon laser scanning microscopy and image analysis providing objective, quantitative data on smooth muscle cell orientation in intact ureters, avoiding the usual sectioning artifacts. In 36 rat ureter segments, originating from a proximal, middle or distal site and from a left or right ureter, we found close to the adventitia a well-defined longitudinal smooth muscle orientation. Towards the lamina propria, the orientation gradually became slightly more disperse, yet the main orientation remained longitudinal. We conclude that smooth muscle cell orientation in rat ureter is predominantly longitudinal, though the orientation gradually becomes more disperse towards the proprial side. These findings do not support identification of separate layers. The observed longitudinal orientation suggests that smooth muscle contraction would rather cause local shortening of the ureter, than cause luminal constriction. However, the net-like connective tissue of the ureter wall may translate local longitudinal shortening into co-local luminal constriction, facilitating peristalsis. Our quantitative, minimally invasive approach is a crucial step towards more mechanistic insight into ureter peristalsis, and may also be used to study smooth muscle cell orientation in other tube-like structures like gut and blood vessels.

Errors, error detection, error correction and hippocampal-region damage: data and theories.

PubMed

MacKay, Donald G; Johnson, Laura W

2013-11-01

This review and perspective article outlines 15 observational constraints on theories of errors, error detection, and error correction, and their relation to hippocampal-region (HR) damage. The core observations come from 10 studies with H.M., an amnesic with cerebellar and HR damage but virtually no neocortical damage. Three studies examined the detection of errors planted in visual scenes (e.g., a bird flying in a fish bowl in a school classroom) and sentences (e.g., I helped themselves to the birthday cake). In all three experiments, H.M. detected reliably fewer errors than carefully matched memory-normal controls. Other studies examined the detection and correction of self-produced errors, with controls for comprehension of the instructions, impaired visual acuity, temporal factors, motoric slowing, forgetting, excessive memory load, lack of motivation, and deficits in visual scanning or attention. In these studies, H.M. corrected reliably fewer errors than memory-normal and cerebellar controls, and his uncorrected errors in speech, object naming, and reading aloud exhibited two consistent features: omission and anomaly. For example, in sentence production tasks, H.M. omitted one or more words in uncorrected encoding errors that rendered his sentences anomalous (incoherent, incomplete, or ungrammatical) reliably more often than controls. Besides explaining these core findings, the theoretical principles discussed here explain H.M.'s retrograde amnesia for once familiar episodic and semantic information; his anterograde amnesia for novel information; his deficits in visual cognition, sentence comprehension, sentence production, sentence reading, and object naming; and effects of aging on his ability to read isolated low frequency words aloud. These theoretical principles also explain a wide range of other data on error detection and correction and generate new predictions for future test. Copyright © 2013 Elsevier Ltd. All rights reserved.

Symbol Error Rate of Underlay Cognitive Relay Systems over Rayleigh Fading Channel

NASA Astrophysics Data System (ADS)

Ho van, Khuong; Bao, Vo Nguyen Quoc

Underlay cognitive systems allow secondary users (SUs) to access the licensed band allocated to primary users (PUs) for better spectrum utilization with the power constraint imposed on SUs such that their operation does not harm the normal communication of PUs. This constraint, which limits the coverage range of SUs, can be offset by relaying techniques that take advantage of shorter range communication for lower path loss. Symbol error rate (SER) analysis of underlay cognitive relay systems over fading channel has not been reported in the literature. This paper fills this gap. The derived SER expressions are validated by simulations and show that underlay cognitive relay systems suffer a high error floor for any modulation level.

Additional Smooth and Rough Water Trials of SKI-CAT.

DTIC Science & Technology

1981-08-01

REPORT & PERIOD COVERED ADDITIONAL SMOOTH AND ROUGH WATER TRIALS OF FINAL SKI- CAT S. PERFORMING ORO. REPORT NUMSER 7. AUTHOR() I. CONTRACT OR GRANT NUMUr...Identif by bloc membe) ’ " -Further tests of SKI- CAT were made in smooth and rough water. Smooth water results confirmed the performance results of...reductions in the accelerations and motions of SKI- CAT over against the head seasreut DD , +A ,3 1473 EDITION OF I NOVS IS OBSOLETE UNCIbSJFIED SIME 0102-014

A unified framework for spiking and gap-junction interactions in distributed neuronal network simulations.

PubMed

Hahne, Jan; Helias, Moritz; Kunkel, Susanne; Igarashi, Jun; Bolten, Matthias; Frommer, Andreas; Diesmann, Markus

2015-01-01

Contemporary simulators for networks of point and few-compartment model neurons come with a plethora of ready-to-use neuron and synapse models and support complex network topologies. Recent technological advancements have broadened the spectrum of application further to the efficient simulation of brain-scale networks on supercomputers. In distributed network simulations the amount of spike data that accrues per millisecond and process is typically low, such that a common optimization strategy is to communicate spikes at relatively long intervals, where the upper limit is given by the shortest synaptic transmission delay in the network. This approach is well-suited for simulations that employ only chemical synapses but it has so far impeded the incorporation of gap-junction models, which require instantaneous neuronal interactions. Here, we present a numerical algorithm based on a waveform-relaxation technique which allows for network simulations with gap junctions in a way that is compatible with the delayed communication strategy. Using a reference implementation in the NEST simulator, we demonstrate that the algorithm and the required data structures can be smoothly integrated with existing code such that they complement the infrastructure for spiking connections. To show that the unified framework for gap-junction and spiking interactions achieves high performance and delivers high accuracy in the presence of gap junctions, we present benchmarks for workstations, clusters, and supercomputers. Finally, we discuss limitations of the novel technology.

A multi-source precipitation approach to fill gaps over a radar precipitation field

NASA Astrophysics Data System (ADS)

Tesfagiorgis, K. B.; Mahani, S. E.; Khanbilvardi, R.

2012-12-01

Satellite Precipitation Estimates (SPEs) may be the only available source of information for operational hydrologic and flash flood prediction due to spatial limitations of radar and gauge products. The present work develops an approach to seamlessly blend satellite, radar, climatological and gauge precipitation products to fill gaps over ground-based radar precipitation fields. To mix different precipitation products, the bias of any of the products relative to each other should be removed. For bias correction, the study used an ensemble-based method which aims to estimate spatially varying multiplicative biases in SPEs using a radar rainfall product. Bias factors were calculated for a randomly selected sample of rainy pixels in the study area. Spatial fields of estimated bias were generated taking into account spatial variation and random errors in the sampled values. A weighted Successive Correction Method (SCM) is proposed to make the merging between error corrected satellite and radar rainfall estimates. In addition to SCM, we use a Bayesian spatial method for merging the gap free radar with rain gauges, climatological rainfall sources and SPEs. We demonstrate the method using SPE Hydro-Estimator (HE), radar- based Stage-II, a climatological product PRISM and rain gauge dataset for several rain events from 2006 to 2008 over three different geographical locations of the United States. Results show that: the SCM method in combination with the Bayesian spatial model produced a precipitation product in good agreement with independent measurements. The study implies that using the available radar pixels surrounding the gap area, rain gauge, PRISM and satellite products, a radar like product is achievable over radar gap areas that benefits the scientific community.

Measuring, Achieving, And Promoting Smoothness Of Virginia's Asphalt Overlays

DOT National Transportation Integrated Search

1999-04-01

This study was initiated with the goal of identifying the predominant factors affecting the achievable smoothness of asphalt overlays. In addition, the researcher chronicles the evolution of Virginia's innovative special provision for smoothness, whi...

Modeling the dispersion effects of contractile fibers in smooth muscles

NASA Astrophysics Data System (ADS)

Murtada, Sae-Il; Kroon, Martin; Holzapfel, Gerhard A.

2010-12-01

Micro-structurally based models for smooth muscle contraction are crucial for a better understanding of pathological conditions such as atherosclerosis, incontinence and asthma. It is meaningful that models consider the underlying mechanical structure and the biochemical activation. Hence, a simple mechanochemical model is proposed that includes the dispersion of the orientation of smooth muscle myofilaments and that is capable to capture available experimental data on smooth muscle contraction. This allows a refined study of the effects of myofilament dispersion on the smooth muscle contraction. A classical biochemical model is used to describe the cross-bridge interactions with the thin filament in smooth muscles in which calcium-dependent myosin phosphorylation is the only regulatory mechanism. A novel mechanical model considers the dispersion of the contractile fiber orientations in smooth muscle cells by means of a strain-energy function in terms of one dispersion parameter. All model parameters have a biophysical meaning and may be estimated through comparisons with experimental data. The contraction of the middle layer of a carotid artery is studied numerically. Using a tube the relationships between the internal pressure and the stretches are investigated as functions of the dispersion parameter, which implies a strong influence of the orientation of smooth muscle myofilaments on the contraction response. It is straightforward to implement this model in a finite element code to better analyze more complex boundary-value problems.

An effective approach for gap-filling continental scale remotely sensed time-series

PubMed Central

Weiss, Daniel J.; Atkinson, Peter M.; Bhatt, Samir; Mappin, Bonnie; Hay, Simon I.; Gething, Peter W.

2014-01-01

The archives of imagery and modeled data products derived from remote sensing programs with high temporal resolution provide powerful resources for characterizing inter- and intra-annual environmental dynamics. The impressive depth of available time-series from such missions (e.g., MODIS and AVHRR) affords new opportunities for improving data usability by leveraging spatial and temporal information inherent to longitudinal geospatial datasets. In this research we develop an approach for filling gaps in imagery time-series that result primarily from cloud cover, which is particularly problematic in forested equatorial regions. Our approach consists of two, complementary gap-filling algorithms and a variety of run-time options that allow users to balance competing demands of model accuracy and processing time. We applied the gap-filling methodology to MODIS Enhanced Vegetation Index (EVI) and daytime and nighttime Land Surface Temperature (LST) datasets for the African continent for 2000–2012, with a 1 km spatial resolution, and an 8-day temporal resolution. We validated the method by introducing and filling artificial gaps, and then comparing the original data with model predictions. Our approach achieved R2 values above 0.87 even for pixels within 500 km wide introduced gaps. Furthermore, the structure of our approach allows estimation of the error associated with each gap-filled pixel based on the distance to the non-gap pixels used to model its fill value, thus providing a mechanism for including uncertainty associated with the gap-filling process in downstream applications of the resulting datasets. PMID:25642100

Applicability of AgMERRA Forcing Dataset to Fill Gaps in Historical in-situ Meteorological Data

NASA Astrophysics Data System (ADS)

Bannayan, M.; Lashkari, A.; Zare, H.; Asadi, S.; Salehnia, N.

2015-12-01

Integrated assessment studies of food production systems use crop models to simulate the effects of climate and socio-economic changes on food security. Climate forcing data is one of those key inputs of crop models. This study evaluated the performance of AgMERRA climate forcing dataset to fill gaps in historical in-situ meteorological data for different climatic regions of Iran. AgMERRA dataset intercompared with in- situ observational dataset for daily maximum and minimum temperature and precipitation during 1980-2010 periods via Root Mean Square error (RMSE), Mean Absolute Error (MAE) and Mean Bias Error (MBE) for 17 stations in four climatic regions included humid and moderate, cold, dry and arid, hot and humid. Moreover, probability distribution function and cumulative distribution function compared between model and observed data. The results of measures of agreement between AgMERRA data and observed data demonstrated that there are small errors in model data for all stations. Except for stations which are located in cold regions, model data in the other stations illustrated under-prediction for daily maximum temperature and precipitation. However, it was not significant. In addition, probability distribution function and cumulative distribution function showed the same trend for all stations between model and observed data. Therefore, the reliability of AgMERRA dataset is high to fill gaps in historical observations in different climatic regions of Iran as well as it could be applied as a basis for future climate scenarios.

Measuring, achieving and promoting smoothness of Virginia's asphalt overlays.

DOT National Transportation Integrated Search

1999-01-01

This study was initiated with the goal of identifying the predominant factors affecting the achievable smoothness of asphalt overlays. In addition, it chronicles the evolution of Virginia's innovative special provision for smoothness, which was devel...

Neurophysiology and Neuroanatomy of Smooth Pursuit: Lesion Studies

ERIC Educational Resources Information Center

Sharpe, James A.

2008-01-01

Smooth pursuit impairment is recognized clinically by the presence of saccadic tracking of a small object and quantified by reduction in pursuit gain, the ratio of smooth eye movement velocity to the velocity of a foveal target. Correlation of the site of brain lesions, identified by imaging or neuropathological examination, with defective smooth…

GapBlaster-A Graphical Gap Filler for Prokaryote Genomes.

PubMed

de Sá, Pablo H C G; Miranda, Fábio; Veras, Adonney; de Melo, Diego Magalhães; Soares, Siomar; Pinheiro, Kenny; Guimarães, Luis; Azevedo, Vasco; Silva, Artur; Ramos, Rommel T J

2016-01-01

The advent of NGS (Next Generation Sequencing) technologies has resulted in an exponential increase in the number of complete genomes available in biological databases. This advance has allowed the development of several computational tools enabling analyses of large amounts of data in each of the various steps, from processing and quality filtering to gap filling and manual curation. The tools developed for gap closure are very useful as they result in more complete genomes, which will influence downstream analyses of genomic plasticity and comparative genomics. However, the gap filling step remains a challenge for genome assembly, often requiring manual intervention. Here, we present GapBlaster, a graphical application to evaluate and close gaps. GapBlaster was developed via Java programming language. The software uses contigs obtained in the assembly of the genome to perform an alignment against a draft of the genome/scaffold, using BLAST or Mummer to close gaps. Then, all identified alignments of contigs that extend through the gaps in the draft sequence are presented to the user for further evaluation via the GapBlaster graphical interface. GapBlaster presents significant results compared to other similar software and has the advantage of offering a graphical interface for manual curation of the gaps. GapBlaster program, the user guide and the test datasets are freely available at https://sourceforge.net/projects/gapblaster2015/. It requires Sun JDK 8 and Blast or Mummer.

Novel treatment strategies for smooth muscle disorders: Targeting Kv7 potassium channels.

PubMed

Haick, Jennifer M; Byron, Kenneth L

2016-09-01

Smooth muscle cells provide crucial contractile functions in visceral, vascular, and lung tissues. The contractile state of smooth muscle is largely determined by their electrical excitability, which is in turn influenced by the activity of potassium channels. The activity of potassium channels sustains smooth muscle cell membrane hyperpolarization, reducing cellular excitability and thereby promoting smooth muscle relaxation. Research over the past decade has indicated an important role for Kv7 (KCNQ) voltage-gated potassium channels in the regulation of the excitability of smooth muscle cells. Expression of multiple Kv7 channel subtypes has been demonstrated in smooth muscle cells from viscera (gastrointestinal, bladder, myometrial), from the systemic and pulmonary vasculature, and from the airways of the lung, from multiple species, including humans. A number of clinically used drugs, some of which were developed to target Kv7 channels in other tissues, have been found to exert robust effects on smooth muscle Kv7 channels. Functional studies have indicated that Kv7 channel activators and inhibitors have the ability to relax and contact smooth muscle preparations, respectively, suggesting a wide range of novel applications for the pharmacological tool set. This review summarizes recent findings regarding the physiological functions of Kv7 channels in smooth muscle, and highlights potential therapeutic applications based on pharmacological targeting of smooth muscle Kv7 channels throughout the body. Published by Elsevier Inc.

Smoothing of climate time series revisited

NASA Astrophysics Data System (ADS)

Mann, Michael E.

2008-08-01

We present an easily implemented method for smoothing climate time series, generalizing upon an approach previously described by Mann (2004). The method adaptively weights the three lowest order time series boundary constraints to optimize the fit with the raw time series. We apply the method to the instrumental global mean temperature series from 1850-2007 and to various surrogate global mean temperature series from 1850-2100 derived from the CMIP3 multimodel intercomparison project. These applications demonstrate that the adaptive method systematically out-performs certain widely used default smoothing methods, and is more likely to yield accurate assessments of long-term warming trends.

Error analysis of filtering operations in pixel-duplicated images of diabetic retinopathy

NASA Astrophysics Data System (ADS)

Mehrubeoglu, Mehrube; McLauchlan, Lifford

2010-08-01

In this paper, diabetic retinopathy is chosen for a sample target image to demonstrate the effectiveness of image enlargement through pixel duplication in identifying regions of interest. Pixel duplication is presented as a simpler alternative to data interpolation techniques for detecting small structures in the images. A comparative analysis is performed on different image processing schemes applied to both original and pixel-duplicated images. Structures of interest are detected and and classification parameters optimized for minimum false positive detection in the original and enlarged retinal pictures. The error analysis demonstrates the advantages as well as shortcomings of pixel duplication in image enhancement when spatial averaging operations (smoothing filters) are also applied.

Young Craters on Smooth Plains

NASA Image and Video Library

2000-01-15

This image, from NASA Mariner 10 spacecraft which launched in 1974, shows young craters superposed on smooth plains. Larger young craters have central peaks, flat floors, terraced walls, and radial ejecta deposits.

Towards autonomous locomotion: CPG-based control of smooth 3D slithering gait transition of a snake-like robot.

PubMed

Bing, Zhenshan; Cheng, Long; Chen, Guang; Röhrbein, Florian; Huang, Kai; Knoll, Alois

2017-04-04

Snake-like robots with 3D locomotion ability have significant advantages of adaptive travelling in diverse complex terrain over traditional legged or wheeled mobile robots. Despite numerous developed gaits, these snake-like robots suffer from unsmooth gait transitions by changing the locomotion speed, direction, and body shape, which would potentially cause undesired movement and abnormal torque. Hence, there exists a knowledge gap for snake-like robots to achieve autonomous locomotion. To address this problem, this paper presents the smooth slithering gait transition control based on a lightweight central pattern generator (CPG) model for snake-like robots. First, based on the convergence behavior of the gradient system, a lightweight CPG model with fast computing time was designed and compared with other widely adopted CPG models. Then, by reshaping the body into a more stable geometry, the slithering gait was modified, and studied based on the proposed CPG model, including the gait transition of locomotion speed, moving direction, and body shape. In contrast to sinusoid-based method, extensive simulations and prototype experiments finally demonstrated that smooth slithering gait transition can be effectively achieved using the proposed CPG-based control method without generating undesired locomotion and abnormal torque.

Quantum steganography and quantum error-correction

NASA Astrophysics Data System (ADS)

Shaw, Bilal A.

Quantum error-correcting codes have been the cornerstone of research in quantum information science (QIS) for more than a decade. Without their conception, quantum computers would be a footnote in the history of science. When researchers embraced the idea that we live in a world where the effects of a noisy environment cannot completely be stripped away from the operations of a quantum computer, the natural way forward was to think about importing classical coding theory into the quantum arena to give birth to quantum error-correcting codes which could help in mitigating the debilitating effects of decoherence on quantum data. We first talk about the six-qubit quantum error-correcting code and show its connections to entanglement-assisted error-correcting coding theory and then to subsystem codes. This code bridges the gap between the five-qubit (perfect) and Steane codes. We discuss two methods to encode one qubit into six physical qubits. Each of the two examples corrects an arbitrary single-qubit error. The first example is a degenerate six-qubit quantum error-correcting code. We explicitly provide the stabilizer generators, encoding circuits, codewords, logical Pauli operators, and logical CNOT operator for this code. We also show how to convert this code into a non-trivial subsystem code that saturates the subsystem Singleton bound. We then prove that a six-qubit code without entanglement assistance cannot simultaneously possess a Calderbank-Shor-Steane (CSS) stabilizer and correct an arbitrary single-qubit error. A corollary of this result is that the Steane seven-qubit code is the smallest single-error correcting CSS code. Our second example is the construction of a non-degenerate six-qubit CSS entanglement-assisted code. This code uses one bit of entanglement (an ebit) shared between the sender (Alice) and the receiver (Bob) and corrects an arbitrary single-qubit error. The code we obtain is globally equivalent to the Steane seven-qubit code and thus

Learning time-dependent noise to reduce logical errors: real time error rate estimation in quantum error correction

NASA Astrophysics Data System (ADS)

Huo, Ming-Xia; Li, Ying

2017-12-01

Quantum error correction is important to quantum information processing, which allows us to reliably process information encoded in quantum error correction codes. Efficient quantum error correction benefits from the knowledge of error rates. We propose a protocol for monitoring error rates in real time without interrupting the quantum error correction. Any adaptation of the quantum error correction code or its implementation circuit is not required. The protocol can be directly applied to the most advanced quantum error correction techniques, e.g. surface code. A Gaussian processes algorithm is used to estimate and predict error rates based on error correction data in the past. We find that using these estimated error rates, the probability of error correction failures can be significantly reduced by a factor increasing with the code distance.

Detection thresholds for gaps, overlaps, and no-gap-no-overlaps.

PubMed

Heldner, Mattias

2011-07-01

Detection thresholds for gaps and overlaps, that is acoustic and perceived silences and stretches of overlapping speech in speaker changes, were determined. Subliminal gaps and overlaps were categorized as no-gap-no-overlaps. The established gap and overlap detection thresholds both corresponded to the duration of a long vowel, or about 120 ms. These detection thresholds are valuable for mapping the perceptual speaker change categories gaps, overlaps, and no-gap-no-overlaps into the acoustic domain. Furthermore, the detection thresholds allow generation and understanding of gaps, overlaps, and no-gap-no-overlaps in human-like spoken dialogue systems. © 2011 Acoustical Society of America

Non-smooth saddle-node bifurcations III: Strange attractors in continuous time

NASA Astrophysics Data System (ADS)

Fuhrmann, G.

2016-08-01

Non-smooth saddle-node bifurcations give rise to minimal sets of interesting geometry built of so-called strange non-chaotic attractors. We show that certain families of quasiperiodically driven logistic differential equations undergo a non-smooth bifurcation. By a previous result on the occurrence of non-smooth bifurcations in forced discrete time dynamical systems, this yields that within the class of families of quasiperiodically driven differential equations, non-smooth saddle-node bifurcations occur in a set with non-empty C2-interior.

{beta}-Catenin regulates airway smooth muscle contraction.

PubMed

Jansen, Sepp R; Van Ziel, Anna M; Baarsma, Hoeke A; Gosens, Reinoud

2010-08-01

beta-Catenin is an 88-kDa member of the armadillo family of proteins that is associated with the cadherin-catenin complex in the plasma membrane. This complex interacts dynamically with the actin cytoskeleton to stabilize adherens junctions, which play a central role in force transmission by smooth muscle cells. Therefore, in the present study, we hypothesized a role for beta-catenin in the regulation of smooth muscle force production. beta-Catenin colocalized with smooth muscle alpha-actin (sm-alpha-actin) and N-cadherin in plasma membrane fractions and coimmunoprecipitated with sm-alpha-actin and N-cadherin in lysates of bovine tracheal smooth muscle (BTSM) strips. Moreover, immunocytochemistry of cultured BTSM cells revealed clear and specific colocalization of sm-alpha-actin and beta-catenin at the sites of cell-cell contact. Treatment of BTSM strips with the pharmacological beta-catenin/T cell factor-4 (TCF4) inhibitor PKF115-584 (100 nM) reduced beta-catenin expression in BTSM whole tissue lysates and in plasma membrane fractions and reduced maximal KCl- and methacholine-induced force production. These changes in force production were not accompanied by changes in the expression of sm-alpha-actin or sm-myosin heavy chain (MHC). Likewise, small interfering RNA (siRNA) knockdown of beta-catenin in BTSM strips reduced beta-catenin expression and attenuated maximal KCl- and methacholine-induced contractions without affecting sm-alpha-actin or sm-MHC expression. Conversely, pharmacological (SB-216763, LiCl) or insulin-induced inhibition of glycogen synthase kinase-3 (GSK-3) enhanced the expression of beta-catenin and augmented maximal KCl- and methacholine-induced contractions. We conclude that beta-catenin is a plasma membrane-associated protein in airway smooth muscle that regulates active tension development, presumably by stabilizing cell-cell contacts and thereby supporting force transmission between neighboring cells.

Mn/DOT combined smoothness specification.

DOT National Transportation Integrated Search

2010-04-01

This report presents the development of a combined smoothness specification for asphalt and concrete pavements : and associated training for the certification of profiler operators by highway agencies. The report discusses the : analyses conducted to...

Error and Error Mitigation in Low-Coverage Genome Assemblies

PubMed Central

Hubisz, Melissa J.; Lin, Michael F.; Kellis, Manolis; Siepel, Adam

2011-01-01

The recent release of twenty-two new genome sequences has dramatically increased the data available for mammalian comparative genomics, but twenty of these new sequences are currently limited to ∼2× coverage. Here we examine the extent of sequencing error in these 2× assemblies, and its potential impact in downstream analyses. By comparing 2× assemblies with high-quality sequences from the ENCODE regions, we estimate the rate of sequencing error to be 1–4 errors per kilobase. While this error rate is fairly modest, sequencing error can still have surprising effects. For example, an apparent lineage-specific insertion in a coding region is more likely to reflect sequencing error than a true biological event, and the length distribution of coding indels is strongly distorted by error. We find that most errors are contributed by a small fraction of bases with low quality scores, in particular, by the ends of reads in regions of single-read coverage in the assembly. We explore several approaches for automatic sequencing error mitigation (SEM), making use of the localized nature of sequencing error, the fact that it is well predicted by quality scores, and information about errors that comes from comparisons across species. Our automatic methods for error mitigation cannot replace the need for additional sequencing, but they do allow substantial fractions of errors to be masked or eliminated at the cost of modest amounts of over-correction, and they can reduce the impact of error in downstream phylogenomic analyses. Our error-mitigated alignments are available for download. PMID:21340033

Distortion Representation of Forecast Errors for Model Skill Assessment and Objective Analysis. Revision 1.12

NASA Technical Reports Server (NTRS)

Hoffman, Ross N.; Nehrkorn, Thomas; Grassotti, Christopher

1997-01-01

We proposed a novel characterization of errors for numerical weather predictions. In its simplest form we decompose the error into a part attributable to phase errors and a remainder. The phase error is represented in the same fashion as a velocity field and is required to vary slowly and smoothly with position. A general distortion representation allows for the displacement and amplification or bias correction of forecast anomalies. Characterizing and decomposing forecast error in this way has two important applications, which we term the assessment application and the objective analysis application. For the assessment application, our approach results in new objective measures of forecast skill which are more in line with subjective measures of forecast skill and which are useful in validating models and diagnosing their shortcomings. With regard to the objective analysis application, meteorological analysis schemes balance forecast error and observational error to obtain an optimal analysis. Presently, representations of the error covariance matrix used to measure the forecast error are severely limited. For the objective analysis application our approach will improve analyses by providing a more realistic measure of the forecast error. We expect, a priori, that our approach should greatly improve the utility of remotely sensed data which have relatively high horizontal resolution, but which are indirectly related to the conventional atmospheric variables. In this project, we are initially focusing on the assessment application, restricted to a realistic but univariate 2-dimensional situation. Specifically, we study the forecast errors of the sea level pressure (SLP) and 500 hPa geopotential height fields for forecasts of the short and medium range. Since the forecasts are generated by the GEOS (Goddard Earth Observing System) data assimilation system with and without ERS 1 scatterometer data, these preliminary studies serve several purposes. They (1) provide a

The convergence analysis of SpikeProp algorithm with smoothing L1∕2 regularization.

PubMed

Zhao, Junhong; Zurada, Jacek M; Yang, Jie; Wu, Wei

2018-07-01

Unlike the first and the second generation artificial neural networks, spiking neural networks (SNNs) model the human brain by incorporating not only synaptic state but also a temporal component into their operating model. However, their intrinsic properties require expensive computation during training. This paper presents a novel algorithm to SpikeProp for SNN by introducing smoothing L 1∕2 regularization term into the error function. This algorithm makes the network structure sparse, with some smaller weights that can be eventually removed. Meanwhile, the convergence of this algorithm is proved under some reasonable conditions. The proposed algorithms have been tested for the convergence speed, the convergence rate and the generalization on the classical XOR-problem, Iris problem and Wisconsin Breast Cancer classification. Copyright © 2018 Elsevier Ltd. All rights reserved.

Recovery of chemical Estimates by Field Inhomogeneity Neighborhood Error Detection (REFINED): Fat/Water Separation at 7T

PubMed Central

Narayan, Sreenath; Kalhan, Satish C.; Wilson, David L.

2012-01-01

I.Abstract Purpose To reduce swaps in fat-water separation methods, a particular issue on 7T small animal scanners due to field inhomogeneity, using image postprocessing innovations that detect and correct errors in the B0 field map. Materials and Methods Fat-water decompositions and B0 field maps were computed for images of mice acquired on a 7T Bruker BioSpec scanner, using a computationally efficient method for solving the Markov Random Field formulation of the multi-point Dixon model. The B0 field maps were processed with a novel hole-filling method, based on edge strength between regions, and a novel k-means method, based on field-map intensities, which were iteratively applied to automatically detect and reinitialize error regions in the B0 field maps. Errors were manually assessed in the B0 field maps and chemical parameter maps both before and after error correction. Results Partial swaps were found in 6% of images when processed with FLAWLESS. After REFINED correction, only 0.7% of images contained partial swaps, resulting in an 88% decrease in error rate. Complete swaps were not problematic. Conclusion Ex post facto error correction is a viable supplement to a priori techniques for producing globally smooth B0 field maps, without partial swaps. With our processing pipeline, it is possible to process image volumes rapidly, robustly, and almost automatically. PMID:23023815

Recovery of chemical estimates by field inhomogeneity neighborhood error detection (REFINED): fat/water separation at 7 tesla.

PubMed

Narayan, Sreenath; Kalhan, Satish C; Wilson, David L

2013-05-01

To reduce swaps in fat-water separation methods, a particular issue on 7 Tesla (T) small animal scanners due to field inhomogeneity, using image postprocessing innovations that detect and correct errors in the B0 field map. Fat-water decompositions and B0 field maps were computed for images of mice acquired on a 7T Bruker BioSpec scanner, using a computationally efficient method for solving the Markov Random Field formulation of the multi-point Dixon model. The B0 field maps were processed with a novel hole-filling method, based on edge strength between regions, and a novel k-means method, based on field-map intensities, which were iteratively applied to automatically detect and reinitialize error regions in the B0 field maps. Errors were manually assessed in the B0 field maps and chemical parameter maps both before and after error correction. Partial swaps were found in 6% of images when processed with FLAWLESS. After REFINED correction, only 0.7% of images contained partial swaps, resulting in an 88% decrease in error rate. Complete swaps were not problematic. Ex post facto error correction is a viable supplement to a priori techniques for producing globally smooth B0 field maps, without partial swaps. With our processing pipeline, it is possible to process image volumes rapidly, robustly, and almost automatically. Copyright © 2012 Wiley Periodicals, Inc.

Geographic smoothing of solar PV: Results from Gujarat

DOE PAGES

Klima, Kelly; Apt, Jay

2015-09-24

We examine the potential for geographic smoothing of solar photovoltaic (PV) electricity generation using 13 months of observed power production from utility-scale plants in Gujarat, India. To our knowledge, this is the first published analysis of geographic smoothing of solar PV using actual generation data at high time resolution from utility-scale solar PV plants. We use geographic correlation and Fourier transform estimates of the power spectral density (PSD) to characterize the observed variability of operating solar PV plants as a function of time scale. Most plants show a spectrum that is linear in the log–log domain at high frequencies f,more » ranging from f -1.23 to f -1.56 (slopes of -1.23 and -1.56), thus exhibiting more relative variability at high frequencies than exhibited by wind plants. PSDs for large PV plants have a steeper slope than those for small plants, hence more smoothing at short time scales. Interconnecting 20 Gujarat plants yields a f -1.66 spectrum, reducing fluctuations at frequencies corresponding to 6 h and 1 h by 23% and 45%, respectively. Half of this smoothing can be obtained through connecting 4-5 plants; reaching marginal improvement of 1% per added plant occurs at 12-14 plants. The largest plant (322 MW) showed an f -1.76 spectrum. Furthermore, this suggests that in Gujarat the potential for smoothing is limited to that obtained by one large plant.« less

Better band gaps for wide-gap semiconductors from a locally corrected exchange-correlation potential that nearly eliminates self-interaction errors

DOE PAGES

Singh, Prashant; Harbola, Manoj K.; Johnson, Duane D.

2017-09-08

Here, this work constitutes a comprehensive and improved account of electronic-structure and mechanical properties of silicon-nitride (more » $${\\rm Si}_{3}$$ $${\\rm N}_{4}$$ ) polymorphs via van Leeuwen and Baerends (LB) exchange-corrected local density approximation (LDA) that enforces the exact exchange potential asymptotic behavior. The calculated lattice constant, bulk modulus, and electronic band structure of $${\\rm Si}_{3}$$ $${\\rm N}_{4}$$ polymorphs are in good agreement with experimental results. We also show that, for a single electron in a hydrogen atom, spherical well, or harmonic oscillator, the LB-corrected LDA reduces the (self-interaction) error to exact total energy to ~10%, a factor of three to four lower than standard LDA, due to a dramatically improved representation of the exchange-potential.« less

Decreased airway narrowing and smooth muscle contraction in hyperresponsive pigs.

PubMed

Turner, Debra J; Noble, Peter B; Lucas, Matthew P; Mitchell, Howard W

2002-10-01

Increased smooth muscle contractility or reduced smooth muscle mechanical loads could account for the excessive airway narrowing and hyperresponsiveness seen in asthma. These mechanisms were investigated by using an allergen-induced porcine model of airway hyperresponsiveness. Airway narrowing to electric field stimulation was measured in isolated bronchial segments, over a range of transmural pressures (0-20 cmH(2)O). Contractile responses to ACh were measured in bronchial segments and in isolated tracheal smooth muscle strips isolated from control and test (ovalbumin sensitized and challenged) pigs. Test airways narrowed less than controls (P < 0.0001). Test pigs showed reduced contractility to ACh, both in isolated bronchi (P < 0.01) and smooth muscle strips (P < 0.01). Thus isolated airways from pigs exhibiting airway hyperresponsiveness in vivo are hyporesponsive in vitro. The decreased narrowing in bronchi from hyperresponsive pigs may be related to decreased smooth muscle contractility. These data suggest that mechanisms external to the airway wall may be important to the hyperresponsive nature of sensitized lungs.

Cisapride stimulates contraction of idiopathic megacolonic smooth muscle in cats.

PubMed

Hasler, A H; Washabau, R J

1997-01-01

We have previously shown that cisapride, a substituted piperidinyl benzamide, stimulates contraction of healthy feline colonic smooth muscle. The purpose of the present investigation was to determine the effect of cisapride on feline idiopathic megacolonic smooth muscle function. Longitudinal smooth muscle strips from ascending and descending colon were obtained from cats with idiopathic megacolon, suspended in a 1.5 mM Ca(2+)-HEPES buffer solution (37 degrees C, 100% O2, pH 7.4), attached to isometric force transducers, and stretched to optimal muscle length (Lo). Control responses were obtained at each muscle site with acetylcholine (10(-8) to 10(-4) M), substance P (10(-11) to 10(-7) M), or potassium chloride (10 to 80 mM). Muscles were then stimulated with cumulative (10(-9) to 10(-6) M) doses of cisapride in the absence or presence of tetrodotoxin (10(-6) M) and atropine (10(-6) M), or in a 0 calcium HEPES buffer solution. In cats with idiopathic megacolon, cisapride stimulated contractions of longitudinal smooth muscle from both the ascending and the descending colon. Cisapride-induced contractions were similar in magnitude to those induced by substance P and acetylcholine in the ascending colon, but were less than those observed in the descending colon. Cisapride-induced contractions in megacolonic smooth muscle were only partially inhibited by tetrodotoxin and atropine, but were virtually abolished by removal of extracellular calcium. We concluded that cisapride-induced contractions of feline megacolonic smooth muscle are largely smooth muscle mediated and dependent on influx of extracellular calcium. Cisapride-induced contractions in megacolonic smooth muscle are only partially dependent on enteric cholinergic nerves. Thus, cisapride may be useful in the treatment of cats with idiopathic megacolon.

Smoothing Forecasting Methods for Academic Library Circulations: An Evaluation and Recommendation.

ERIC Educational Resources Information Center

Brooks, Terrence A.; Forys, John W., Jr.

1986-01-01

Circulation time-series data from 50 midwest academic libraries were used to test 110 variants of 8 smoothing forecasting methods. Data and methodologies and illustrations of two recommended methods--the single exponential smoothing method and Brown's one-parameter linear exponential smoothing method--are given. Eight references are cited. (EJS)

Fault and Error Latency Under Real Workload: an Experimental Study. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Chillarege, Ram

1986-01-01

A practical methodology for the study of fault and error latency is demonstrated under a real workload. This is the first study that measures and quantifies the latency under real workload and fills a major gap in the current understanding of workload-failure relationships. The methodology is based on low level data gathered on a VAX 11/780 during the normal workload conditions of the installation. Fault occurrence is simulated on the data, and the error generation and discovery process is reconstructed to determine latency. The analysis proceeds to combine the low level activity data with high level machine performance data to yield a better understanding of the phenomena. A strong relationship exists between latency and workload and that relationship is quantified. The sampling and reconstruction techniques used are also validated. Error latency in the memory where the operating system resides was studied using data on the physical memory access. Fault latency in the paged section of memory was determined using data from physical memory scans. Error latency in the microcontrol store was studied using data on the microcode access and usage.

Unforced errors and error reduction in tennis

PubMed Central

Brody, H

2006-01-01

Only at the highest level of tennis is the number of winners comparable to the number of unforced errors. As the average player loses many more points due to unforced errors than due to winners by an opponent, if the rate of unforced errors can be reduced, it should lead to an increase in points won. This article shows how players can improve their game by understanding and applying the laws of physics to reduce the number of unforced errors. PMID:16632568

Porcine Stomach Smooth Muscle Force Depends on History-Effects.

PubMed

Tomalka, André; Borsdorf, Mischa; Böl, Markus; Siebert, Tobias

2017-01-01

The stomach serves as food reservoir, mixing organ and absorption area for certain substances, while continually varying its position and size. Large dimensional changes during ingestion and gastric emptying of the stomach are associated with large changes in smooth muscle length. These length changes might induce history-effects, namely force depression (FD) following active muscle shortening and force enhancement (FE) following active muscle stretch. Both effects have impact on the force generating capacity of the stomach, and thus functional relevance. However, less is known about history-effects and active smooth muscle properties of stomach smooth muscle. Thus, the aim of this study was to investigate biomechanical muscle properties as force-length and force-velocity relations (FVR) of porcine stomach smooth muscle strips, extended by the analysis of history-effects on smooth muscle force. Therefore, in total n = 54 tissue strips were dissected in longitudinal direction from the ventral fundus of porcine stomachs. Different isometric, isotonic, and isokinetic contraction protocols were performed during electrical muscle stimulation. Cross-sectional areas (CSA) of smooth muscles were determined from cryo-histological sections stained with Picrosirius Red. Results revealed that maximum smooth muscle tension was 10.4 ± 2.6 N/cm 2 . Maximum shortening velocity ( V max ) and curvature factor ( curv ) of the FVR were 0.04 ± 0.01 [optimum muscle length/s] and 0.36 ± 0.15, respectively. The findings of the present study demonstrated significant ( P < 0.05) FD [up to 32% maximum muscle force ( F im )] and FE (up to 16% F im ) of gastric muscle tissue, respectively. The FE- and FD-values increased with increasing ramp amplitude. This outstanding muscle behavior is not accounted for in existing models so far and strongly supports the idea of a holistic reflection of distinct stomach structure and function. For the first time this study provides a comprehensive set of

Porcine Stomach Smooth Muscle Force Depends on History-Effects

PubMed Central

Tomalka, André; Borsdorf, Mischa; Böl, Markus; Siebert, Tobias

2017-01-01

The stomach serves as food reservoir, mixing organ and absorption area for certain substances, while continually varying its position and size. Large dimensional changes during ingestion and gastric emptying of the stomach are associated with large changes in smooth muscle length. These length changes might induce history-effects, namely force depression (FD) following active muscle shortening and force enhancement (FE) following active muscle stretch. Both effects have impact on the force generating capacity of the stomach, and thus functional relevance. However, less is known about history-effects and active smooth muscle properties of stomach smooth muscle. Thus, the aim of this study was to investigate biomechanical muscle properties as force-length and force-velocity relations (FVR) of porcine stomach smooth muscle strips, extended by the analysis of history-effects on smooth muscle force. Therefore, in total n = 54 tissue strips were dissected in longitudinal direction from the ventral fundus of porcine stomachs. Different isometric, isotonic, and isokinetic contraction protocols were performed during electrical muscle stimulation. Cross-sectional areas (CSA) of smooth muscles were determined from cryo-histological sections stained with Picrosirius Red. Results revealed that maximum smooth muscle tension was 10.4 ± 2.6 N/cm2. Maximum shortening velocity (Vmax) and curvature factor (curv) of the FVR were 0.04 ± 0.01 [optimum muscle length/s] and 0.36 ± 0.15, respectively. The findings of the present study demonstrated significant (P < 0.05) FD [up to 32% maximum muscle force (Fim)] and FE (up to 16% Fim) of gastric muscle tissue, respectively. The FE- and FD-values increased with increasing ramp amplitude. This outstanding muscle behavior is not accounted for in existing models so far and strongly supports the idea of a holistic reflection of distinct stomach structure and function. For the first time this study provides a comprehensive set of stomach

Nonparametric Model of Smooth Muscle Force Production During Electrical Stimulation.

PubMed

Cole, Marc; Eikenberry, Steffen; Kato, Takahide; Sandler, Roman A; Yamashiro, Stanley M; Marmarelis, Vasilis Z

2017-03-01

A nonparametric model of smooth muscle tension response to electrical stimulation was estimated using the Laguerre expansion technique of nonlinear system kernel estimation. The experimental data consisted of force responses of smooth muscle to energy-matched alternating single pulse and burst current stimuli. The burst stimuli led to at least a 10-fold increase in peak force in smooth muscle from Mytilus edulis, despite the constant energy constraint. A linear model did not fit the data. However, a second-order model fit the data accurately, so the higher-order models were not required to fit the data. Results showed that smooth muscle force response is not linearly related to the stimulation power.

Smooth Constrained Heuristic Optimization of a Combinatorial Chemical Space

DTIC Science & Technology

2015-05-01

ARL-TR-7294•MAY 2015 US Army Research Laboratory Smooth ConstrainedHeuristic Optimization of a Combinatorial Chemical Space by Berend Christopher...7294•MAY 2015 US Army Research Laboratory Smooth ConstrainedHeuristic Optimization of a Combinatorial Chemical Space by Berend Christopher...

Relative properties of smooth terminating bands

NASA Astrophysics Data System (ADS)

Afanasjev, A. V.; Ragnarsson, I.

1998-01-01

The relative properties of smooth terminating bands observed in the A ∼ 110 mass region are studied within the effective alignment approach. Theoretical values of ietf are calculated using the configuration-dependent shell-correction model with the cranked Nilsson potential. Reasonable agreement with experiment shows that previous interpretations of these bands are consistent with the present study. Contrary to the case of superdeformed bands, the effective alignments of these bands deviate significantly from the pure single-particle alignments of the corresponding orbitals. This indicates that in the case of smooth terminating bands, the effects associated with changes in equilibrium deformations contribute significantly to the effective alignment.

Vestibular-Related Frontal Cortical Areas and Their Roles in Smooth-Pursuit Eye Movements: Representation of Neck Velocity, Neck-Vestibular Interactions, and Memory-Based Smooth-Pursuit

PubMed Central

Fukushima, Kikuro; Fukushima, Junko; Warabi, Tateo

2011-01-01

Smooth-pursuit eye movements are voluntary responses to small slow-moving objects in the fronto-parallel plane. They evolved in primates, who possess high-acuity foveae, to ensure clear vision about the moving target. The primate frontal cortex contains two smooth-pursuit related areas; the caudal part of the frontal eye fields (FEF) and the supplementary eye fields (SEF). Both areas receive vestibular inputs. We review functional differences between the two areas in smooth-pursuit. Most FEF pursuit neurons signal pursuit parameters such as eye velocity and gaze-velocity, and are involved in canceling the vestibulo-ocular reflex by linear addition of vestibular and smooth-pursuit responses. In contrast, gaze-velocity signals are rarely represented in the SEF. Most FEF pursuit neurons receive neck velocity inputs, while discharge modulation during pursuit and trunk-on-head rotation adds linearly. Linear addition also occurs between neck velocity responses and vestibular responses during head-on-trunk rotation in a task-dependent manner. During cross-axis pursuit–vestibular interactions, vestibular signals effectively initiate predictive pursuit eye movements. Most FEF pursuit neurons discharge during the interaction training after the onset of pursuit eye velocity, making their involvement unlikely in the initial stages of generating predictive pursuit. Comparison of representative signals in the two areas and the results of chemical inactivation during a memory-based smooth-pursuit task indicate they have different roles; the SEF plans smooth-pursuit including working memory of motion–direction, whereas the caudal FEF generates motor commands for pursuit eye movements. Patients with idiopathic Parkinson’s disease were asked to perform this task, since impaired smooth-pursuit and visual working memory deficit during cognitive tasks have been reported in most patients. Preliminary results suggested specific roles of the basal ganglia in memory-based smooth

Airway smooth muscle responsiveness from dogs with airway hyperresponsiveness after O/sub 3/ inhalation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, G.L.; O'Byrne, P.M.; Pashley, M.

1988-07-01

Airway hyperresponsiveness occurs after inhalation of O3 in dogs. The purpose of this study was to examine the responsiveness of trachealis smooth muscle in vitro to electrical field stimulation, exogenous acetylcholine, and potassium chloride from dogs with airway hyperresponsiveness after inhaled O3 in vivo and to compare this with the responsiveness of trachealis muscle from control dogs. In addition, excitatory junction potentials were measured with the use of single and double sucrose gap techniques in both groups of dogs to determine whether inhaled O3 affects the release of acetylcholine from parasympathetic nerves in trachealis muscle. Airway hyperresponsiveness developed in allmore » dogs after inhaled O3 (3 ppm for 30 min). The acetylcholine provocative concentration decreased from 4.11 mg/ml before O3 inhalation to 0.66 mg/ml after O3 (P less than 0.0001). The acetylcholine provocative concentration increased slightly after control inhalation of dry room air. Airway smooth muscle showed increased responses to both electrical field stimulation and exogenous acetylcholine but not to potassium chloride in preparations from dogs with airway hyperresponsiveness in vivo. The increased response to electrical field stimulation was not associated with a change in excitatory junctional potentials. These results suggest that a postjunctional alteration in trachealis muscle function occurs after inhaled O3 in dogs, which may account for airway hyperresponsiveness after O3 in vivo.« less

Research gaps identified during systematic reviews of clinical trials: glass-ionomer cements.

PubMed

Mickenautsch, Steffen

2012-06-29

To report the results of an audit concerning research gaps in clinical trials that were accepted for appraisal in authored and published systematic reviews regarding the application of glass-ionomer cements (GIC) in dental practice Information concerning research gaps in trial precision was extracted, following a framework that included classification of the research gap reasons: 'imprecision of information (results)', 'biased information', 'inconsistency or unknown consistency' and 'not the right information', as well as research gap characterization using PICOS elements: population (P), intervention (I), comparison (C), outcomes (O) and setting (S). Internal trial validity assessment was based on the understanding that successful control for systematic error cannot be assured on the basis of inclusion of adequate methods alone, but also requires empirical evidence about whether such attempt was successful. A comprehensive and interconnected coverage of GIC-related clinical topics was established. The most common reasons found for gaps in trial precision were lack of sufficient trials and lack of sufficient large sample size. Only a few research gaps were ascribed to 'Lack of information' caused by focus on mainly surrogate trial outcomes. According to the chosen assessment criteria, a lack of adequate randomisation, allocation concealment and blinding/masking in trials covering all reviewed GIC topics was noted (selection- and detection/performance bias risk). Trial results appear to be less affected by loss-to-follow-up (attrition bias risk). This audit represents an adjunct of the systematic review articles it has covered. Its results do not change the systematic review's conclusions but highlight existing research gaps concerning the precision and internal validity of reviewed trials in detail. These gaps should be addressed in future GIC-related clinical research.

Local air gap thickness and contact area models for realistic simulation of human thermo-physiological response

NASA Astrophysics Data System (ADS)

Psikuta, Agnes; Mert, Emel; Annaheim, Simon; Rossi, René M.

2018-02-01

To evaluate the quality of new energy-saving and performance-supporting building and urban settings, the thermal sensation and comfort models are often used. The accuracy of these models is related to accurate prediction of the human thermo-physiological response that, in turn, is highly sensitive to the local effect of clothing. This study aimed at the development of an empirical regression model of the air gap thickness and the contact area in clothing to accurately simulate human thermal and perceptual response. The statistical model predicted reliably both parameters for 14 body regions based on the clothing ease allowances. The effect of the standard error in air gap prediction on the thermo-physiological response was lower than the differences between healthy humans. It was demonstrated that currently used assumptions and methods for determination of the air gap thickness can produce a substantial error for all global, mean, and local physiological parameters, and hence, lead to false estimation of the resultant physiological state of the human body, thermal sensation, and comfort. Thus, this model may help researchers to strive for improvement of human thermal comfort, health, productivity, safety, and overall sense of well-being with simultaneous reduction of energy consumption and costs in built environment.

Smooth invariant densities for random switching on the torus

NASA Astrophysics Data System (ADS)

Bakhtin, Yuri; Hurth, Tobias; Lawley, Sean D.; Mattingly, Jonathan C.

2018-04-01

We consider a random dynamical system obtained by switching between the flows generated by two smooth vector fields on the 2d-torus, with the random switchings happening according to a Poisson process. Assuming that the driving vector fields are transversal to each other at all points of the torus and that each of them allows for a smooth invariant density and no periodic orbits, we prove that the switched system also has a smooth invariant density, for every switching rate. Our approach is based on an integration by parts formula inspired by techniques from Malliavin calculus.

Smoothing optimization of supporting quadratic surfaces with Zernike polynomials

NASA Astrophysics Data System (ADS)

Zhang, Hang; Lu, Jiandong; Liu, Rui; Ma, Peifu

2018-03-01

A new optimization method to get a smooth freeform optical surface from an initial surface generated by the supporting quadratic method (SQM) is proposed. To smooth the initial surface, a 9-vertex system from the neighbor quadratic surface and the Zernike polynomials are employed to establish a linear equation system. A local optimized surface to the 9-vertex system can be build by solving the equations. Finally, a continuous smooth optimization surface is constructed by stitching the above algorithm on the whole initial surface. The spot corresponding to the optimized surface is no longer discrete pixels but a continuous distribution.

Relating the defect band gap and the density functional band gap

NASA Astrophysics Data System (ADS)

Schultz, Peter; Edwards, Arthur

2014-03-01

Density functional theory (DFT) is an important tool to probe the physics of materials. The Kohn-Sham (KS) gap in DFT is typically (much) smaller than the observed band gap for materials in nature, the infamous ``band gap problem.'' Accurate prediction of defect energy levels is often claimed to be a casualty--the band gap defines the energy scale for defect levels. By applying rigorous control of boundary conditions in size-converged supercell calculations, however, we compute defect levels in Si and GaAs with accuracies of ~0.1 eV, across the full gap, unhampered by a band gap problem. Using GaAs as a theoretical laboratory, we show that the defect band gap--the span of computed defect levels--is insensitive to variations in the KS gap (with functional and pseudopotential), these KS gaps ranging from 0.1 to 1.1 eV. The defect gap matches the experimental 1.52 eV gap. The computed defect gaps for several other III-V, II-VI, I-VII, and other compounds also agree with the experimental gap, and show no correlation with the KS gap. Where, then, is the band gap problem? This talk presents these results, discusses why the defect gap and the KS gap are distinct, implying that current understanding of what the ``band gap problem'' means--and how to ``fix'' it--need to be rethought. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy's NNSA under contract DE-AC04-94AL85000.

Recurrent high anion gap metabolic acidosis secondary to 5-oxoproline (pyroglutamic acid).

PubMed

Tailor, Prayus; Raman, Tuhina; Garganta, Cheryl L; Njalsson, Runa; Carlsson, Katarina; Ristoff, Ellinor; Carey, Hugh B

2005-07-01

High anion gap metabolic acidosis in adults is a severe metabolic disorder for which the primary organic acid usually is apparent by clinical history and standard laboratory testing. We report a case of recurrent high anion gap metabolic acidosis in a 48-year-old man who initially presented with anorexia and malaise. Physical examination was unrevealing. Arterial pH was 6.98, P co 2 was 5 mm Hg, and chemistry tests showed a bicarbonate level of 3 mEq/L (3 mmol/L), anion gap of 32 mEq/L (32 mmol/L), and a negative toxicology screen result, except for an acetaminophen (paracetamol) level of 7.5 mug/mL. Metabolic acidosis resolved with administration of intravenous fluids. Subsequently, he experienced 5 more episodes of high anion gap metabolic acidosis during an 8-month span. Methanol, ethylene glycol, acetone, ethanol, d -lactate, and hippuric acid screens were negative. Lactate levels were modestly elevated, and acetaminophen levels were elevated for 5 of 6 admissions. These episodes defied explanation until 3 urinary organic acid screens, obtained on separate admissions, showed striking elevations of 5-oxoproline levels. Inborn errors of metabolism in the gamma-glutamyl cycle causing recurrent 5-oxoprolinuria and high anion gap metabolic acidosis are rare, but well described in children. Recently, there have been several reports of apparent acquired 5-oxoprolinuria and high anion gap metabolic acidosis in adults in association with acetaminophen use. Acetaminophen may, in susceptible individuals, disrupt regulation of the gamma-glutamyl cycle and result in excessive 5-oxoproline production. Suspicion for 5-oxoproline-associated high anion gap metabolic acidosis should be entertained when the cause of high anion gap metabolic acidosis remains poorly defined, the anion gap cannot be explained reasonably by measured organic acids, and there is concomitant acetaminophen use.

Impedance computed tomography using an adaptive smoothing coefficient algorithm.

PubMed

Suzuki, A; Uchiyama, A

2001-01-01

In impedance computed tomography, a fixed coefficient regularization algorithm has been frequently used to improve the ill-conditioning problem of the Newton-Raphson algorithm. However, a lot of experimental data and a long period of computation time are needed to determine a good smoothing coefficient because a good smoothing coefficient has to be manually chosen from a number of coefficients and is a constant for each iteration calculation. Thus, sometimes the fixed coefficient regularization algorithm distorts the information or fails to obtain any effect. In this paper, a new adaptive smoothing coefficient algorithm is proposed. This algorithm automatically calculates the smoothing coefficient from the eigenvalue of the ill-conditioned matrix. Therefore, the effective images can be obtained within a short computation time. Also the smoothing coefficient is automatically adjusted by the information related to the real resistivity distribution and the data collection method. In our impedance system, we have reconstructed the resistivity distributions of two phantoms using this algorithm. As a result, this algorithm only needs one-fifth the computation time compared to the fixed coefficient regularization algorithm. When compared to the fixed coefficient regularization algorithm, it shows that the image is obtained more rapidly and applicable in real-time monitoring of the blood vessel.

The Effect of Spatial Smoothing on Representational Similarity in a Simple Motor Paradigm

PubMed Central

Hendriks, Michelle H. A.; Daniels, Nicky; Pegado, Felipe; Op de Beeck, Hans P.

2017-01-01

Multi-voxel pattern analyses (MVPA) are often performed on unsmoothed data, which is very different from the general practice of large smoothing extents in standard voxel-based analyses. In this report, we studied the effect of smoothing on MVPA results in a motor paradigm. Subjects pressed four buttons with two different fingers of the two hands in response to auditory commands. Overall, independent of the degree of smoothing, correlational MVPA showed distinctive patterns for the different hands in all studied regions of interest (motor cortex, prefrontal cortex, and auditory cortices). With regard to the effect of smoothing, our findings suggest that results from correlational MVPA show a minor sensitivity to smoothing. Moderate amounts of smoothing (in this case, 1−4 times the voxel size) improved MVPA correlations, from a slight improvement to large improvements depending on the region involved. None of the regions showed signs of a detrimental effect of moderate levels of smoothing. Even higher amounts of smoothing sometimes had a positive effect, most clearly in low-level auditory cortex. We conclude that smoothing seems to have a minor positive effect on MVPA results, thus researchers should be mindful about the choices they make regarding the level of smoothing. PMID:28611726

Practical guidance on representing the heteroscedasticity of residual errors of hydrological predictions

NASA Astrophysics Data System (ADS)

McInerney, David; Thyer, Mark; Kavetski, Dmitri; Kuczera, George

2016-04-01

Appropriate representation of residual errors in hydrological modelling is essential for accurate and reliable probabilistic streamflow predictions. In particular, residual errors of hydrological predictions are often heteroscedastic, with large errors associated with high runoff events. Although multiple approaches exist for representing this heteroscedasticity, few if any studies have undertaken a comprehensive evaluation and comparison of these approaches. This study fills this research gap by evaluating a range of approaches for representing heteroscedasticity in residual errors. These approaches include the 'direct' weighted least squares approach and 'transformational' approaches, such as logarithmic, Box-Cox (with and without fitting the transformation parameter), logsinh and the inverse transformation. The study reports (1) theoretical comparison of heteroscedasticity approaches, (2) empirical evaluation of heteroscedasticity approaches using a range of multiple catchments / hydrological models / performance metrics and (3) interpretation of empirical results using theory to provide practical guidance on the selection of heteroscedasticity approaches. Importantly, for hydrological practitioners, the results will simplify the choice of approaches to represent heteroscedasticity. This will enhance their ability to provide hydrological probabilistic predictions with the best reliability and precision for different catchment types (e.g. high/low degree of ephemerality).

Smooth plains on Mercury. A comparison with Vesta.

NASA Astrophysics Data System (ADS)

Zambon, F.; Capaccioni, F.; Carli, C.; De Sanctis, M. C.; Filacchione, G.; Giacomini, L.

Mercury, the closest planet to the Sun, has been visited by the MESSENGER spacecraft \\citet{solomon2007}. After 3 years of orbit around Mercury a global coverage of the surface has been done revealing that ∼27% of Mercury's surface is covered by smooth plains \\citet{denevi2013}. Large part of Mercury's smooth plain (SP) seems to have volcanic origin. Different composition has been observed, most of the SP have a magnesian alkali-basalt-like composition, while some of them have been interpreted as ultramafic. A further 2% of smooth plains have been identified as Odin-type plains and represent the knobby and hummocky plains surrounding the Caloris basin \\citet{denevi2013}. Application of classification methods \\citet{adams2006} applied to color image data of the MESSENGER wide angle camera (MDIS-WAC) \\citet{MDIS} and a spectral analysis of the spec- trometer data (MASCS-VIRS) \\citet{MASCS} are useful to highlight the differences in composition of the smooth planes. A compa rison between Mercury's SP and those of other solar system bodies, such as Vesta \\citet{desanctis2012}, reveals useful to obtain information on the origin and the evolution of this bodies.

Sequence-based model of gap gene regulatory network.

PubMed

Kozlov, Konstantin; Gursky, Vitaly; Kulakovskiy, Ivan; Samsonova, Maria

2014-01-01

The detailed analysis of transcriptional regulation is crucially important for understanding biological processes. The gap gene network in Drosophila attracts large interest among researches studying mechanisms of transcriptional regulation. It implements the most upstream regulatory layer of the segmentation gene network. The knowledge of molecular mechanisms involved in gap gene regulation is far less complete than that of genetics of the system. Mathematical modeling goes beyond insights gained by genetics and molecular approaches. It allows us to reconstruct wild-type gene expression patterns in silico, infer underlying regulatory mechanism and prove its sufficiency. We developed a new model that provides a dynamical description of gap gene regulatory systems, using detailed DNA-based information, as well as spatial transcription factor concentration data at varying time points. We showed that this model correctly reproduces gap gene expression patterns in wild type embryos and is able to predict gap expression patterns in Kr mutants and four reporter constructs. We used four-fold cross validation test and fitting to random dataset to validate the model and proof its sufficiency in data description. The identifiability analysis showed that most model parameters are well identifiable. We reconstructed the gap gene network topology and studied the impact of individual transcription factor binding sites on the model output. We measured this impact by calculating the site regulatory weight as a normalized difference between the residual sum of squares error for the set of all annotated sites and for the set with the site of interest excluded. The reconstructed topology of the gap gene network is in agreement with previous modeling results and data from literature. We showed that 1) the regulatory weights of transcription factor binding sites show very weak correlation with their PWM score; 2) sites with low regulatory weight are important for the model output; 3

Lateral variation in pavement smoothness

DOT National Transportation Integrated Search

2002-12-01

Current performance-based contracting specifications employ International Roughness Index (IRI) to measure the smoothness of a pavement as perceived by the motorist. This parameter is measured in the outer or right-hand traffic lane and requires an u...

GapFiller: a de novo assembly approach to fill the gap within paired reads

PubMed Central

2012-01-01

Background Next Generation Sequencing technologies are able to provide high genome coverages at a relatively low cost. However, due to limited reads' length (from 30 bp up to 200 bp), specific bioinformatics problems have become even more difficult to solve. De novo assembly with short reads, for example, is more complicated at least for two reasons: first, the overall amount of "noisy" data to cope with increased and, second, as the reads' length decreases the number of unsolvable repeats grows. Our work's aim is to go at the root of the problem by providing a pre-processing tool capable to produce (in-silico) longer and highly accurate sequences from a collection of Next Generation Sequencing reads. Results In this paper a seed-and-extend local assembler is presented. The kernel algorithm is a loop that, starting from a read used as seed, keeps extending it using heuristics whose main goal is to produce a collection of error-free and longer sequences. In particular, GapFiller carefully detects reliable overlaps and operates clustering similar reads in order to reconstruct the missing part between the two ends of the same insert. Our tool's output has been validated on 24 experiments using both simulated and real paired reads datasets. The output sequences are declared correct when the seed-mate is found. In the experiments performed, GapFiller was able to extend high percentages of the processed seeds and find their mates, with a false positives rate that turned out to be nearly negligible. Conclusions GapFiller, starting from a sufficiently high short reads coverage, is able to produce high coverages of accurate longer sequences (from 300 bp up to 3500 bp). The procedure to perform safe extensions, together with the mate-found check, turned out to be a powerful criterion to guarantee contigs' correctness. GapFiller has further potential, as it could be applied in a number of different scenarios, including the post-processing validation of insertions

Surface smoothing, decimation, and their effects on 3D biological specimens.

PubMed

Veneziano, Alessio; Landi, Federica; Profico, Antonio

2018-06-01

Smoothing and decimation filters are commonly used to restore the realistic appearance of virtual biological specimens, but they can cause a loss of topological information of unknown extent. In this study, we analyzed the effect of smoothing and decimation on a 3D mesh to highlight the consequences of an inappropriate use of these filters. Topological noise was simulated on four anatomical regions of the virtual reconstruction of an orangutan cranium. Sequential levels of smoothing and decimation were applied, and their effects were analyzed on the overall topology of the 3D mesh and on linear and volumetric measurements. Different smoothing algorithms affected mesh topology and measurements differently, although the influence on the latter was generally low. Decimation always produced detrimental effects on both topology and measurements. The application of smoothing and decimation, both separate and combined, is capable of recovering topological information. Based on the results, objective guidelines are provided to minimize information loss when using smoothing and decimation on 3D meshes. © 2018 Wiley Periodicals, Inc.

Endogenous Cardiac Troponin T Modulates Ca2+-Mediated Smooth Muscle Contraction

PubMed Central

Kajioka, Shunichi; Takahashi-Yanaga, Fumi; Shahab, Nouval; Onimaru, Mitsuho; Matsuda, Miho; Takahashi, Ryosuke; Asano, Haruhiko; Morita, Hiromitsu; Morimoto, Sachio; Yonemitsu, Yoshikazu; Hayashi, Maya; Seki, Narihito; Sasaguri, Toshiuyki; Hirata, Masato; Nakayama, Shinsuke; Naito, Seiji

2012-01-01

Mechanisms linked to actin filaments have long been thought to cooperate in smooth muscle contraction, although key molecules were unclear. We show evidence that cardiac troponin T (cTnT) substantially contributes to Ca2+-mediated contraction in a physiological range of cytosolic Ca2+ concentration ([Ca2+]i). cTnT was detected in various smooth muscles of the aorta, trachea, gut and urinary bladder, including in humans. Also, cTnT was distributed along with tropomyosin in smooth muscle cells, suggesting that these proteins are ready to cause smooth muscle contraction. In chemically permeabilised smooth muscle of cTnT+/− mice in which cTnT reduced to ~50%, the Ca2+-force relationship was shifted toward greater [Ca2+]i, indicating a sizeable contribution of cTnT to smooth muscle contraction at [Ca2+]i < 1 μM. Furthermore, addition of supplemental TnI and TnC reconstructed a troponin system to enhance contraction. The results indicated that a Tn/Tn-like system on actin-filaments cooperates together with the thick-filament pathway. PMID:23248744

The calculation of band gap energy in zinc oxide films

NASA Astrophysics Data System (ADS)

Arif, Ali; Belahssen, Okba; Gareh, Salim; Benramache, Said

2015-01-01

We investigated the optical properties of undoped zinc oxide thin films as the n-type semiconductor; the thin films were deposited at different precursor molarities by ultrasonic spray and spray pyrolysis techniques. The thin films were deposited at different substrate temperatures ranging between 200 and 500 °C. In this paper, we present a new approach to control the optical gap energy of ZnO thin films by concentration of the ZnO solution and substrate temperatures from experimental data, which were published in international journals. The model proposed to calculate the band gap energy with the Urbach energy was investigated. The relation between the experimental data and theoretical calculation suggests that the band gap energies are predominantly estimated by the Urbach energies, film transparency, and concentration of the ZnO solution and substrate temperatures. The measurements by these proposal models are in qualitative agreements with the experimental data; the correlation coefficient values were varied in the range 0.96-0.99999, indicating high quality representation of data based on Equation (2), so that the relative errors of all calculation are smaller than 4%. Thus, one can suppose that the undoped ZnO thin films are chemically purer and have many fewer defects and less disorder owing to an almost complete chemical decomposition and contained higher optical band gap energy.

Optimization of conditions for thermal smoothing GaAs surfaces

NASA Astrophysics Data System (ADS)

Akhundov, I. O.; Kazantsev, D. M.; Kozhuhov, A. S.; Alperovich, V. L.

2018-03-01

GaAs thermal smoothing by annealing in conditions which are close to equilibrium between the surface and vapors of As and Ga was earlier proved to be effective for the step-terraced surface formation on epi-ready substrates with a small root-mean-square roughness (Rq ≤ 0.15 nm). In the present study, this technique is further developed in order to reduce the annealing duration and to smooth GaAs samples with a larger initial roughness. To this end, we proposed a two-stage anneal with the first high-temperature stage aimed at smoothing "coarse" relief features and the second stage focused on "fine" smoothing at a lower temperature. The optimal temperatures and durations of two-stage annealing are found by Monte Carlo simulations and adjusted after experimentation. It is proved that the temperature and duration of the first high-temperature stage are restricted by the surface roughening, which occurs due to deviations from equilibrium conditions.

Smoothed Particle Hydrodynamic Simulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

2016-10-05

This code is a highly modular framework for developing smoothed particle hydrodynamic (SPH) simulations running on parallel platforms. The compartmentalization of the code allows for rapid development of new SPH applications and modifications of existing algorithms. The compartmentalization also allows changes in one part of the code used by many applications to instantly be made available to all applications.

Star Products with Separation of Variables Admitting a Smooth Extension

NASA Astrophysics Data System (ADS)

Karabegov, Alexander

2012-08-01

Given a complex manifold M with an open dense subset Ω endowed with a pseudo-Kähler form ω which cannot be smoothly extended to a larger open subset, we consider various examples where the corresponding Kähler-Poisson structure and a star product with separation of variables on (Ω, ω) admit smooth extensions to M. We give a simple criterion of the existence of a smooth extension of a star product and apply it to these examples.

Vinpocetine Attenuates the Osteoblastic Differentiation of Vascular Smooth Muscle Cells

PubMed Central

Chen, Xiu-Juan; Wang, Na; Yi, Peng-Fei; Song, Min; Zhang, Bo; Wang, Yu-Zhong; Liang, Qiu-Hua

2016-01-01

Vascular calcification is an active process of osteoblastic differentiation of vascular smooth muscle cells; however, its definite mechanism remains unknown. Vinpocetine, a derivative of the alkaloid vincamine, has been demonstrated to inhibit the high glucose-induced proliferation of vascular smooth muscle cells; however, it remains unknown whether vinpocetine can affect the osteoblastic differentiation of vascular smooth muscle cells. We hereby investigated the effect of vinpocetine on vascular calcification using a beta-glycerophosphate-induced cell model. Our results showed that vinpocetine significantly reduced the osteoblast-like phenotypes of vascular smooth muscle cells including ALP activity, osteocalcin, collagen type I, Runx2 and BMP-2 expression as well as the formation of mineralized nodule. Vinpocetine, binding to translocation protein, induced phosphorylation of extracellular signal-related kinase and Akt and thus inhibited the translocation of nuclear factor-kappa B into the nucleus. Silencing of translocator protein significantly attenuated the inhibitory effect of vinpocetine on osteoblastic differentiation of vascular smooth muscle cells. Taken together, vinpocetine may be a promising candidate for the clinical therapy of vascular calcification. PMID:27589055

Vinpocetine Attenuates the Osteoblastic Differentiation of Vascular Smooth Muscle Cells.

PubMed

Ma, Yun-Yun; Sun, Lin; Chen, Xiu-Juan; Wang, Na; Yi, Peng-Fei; Song, Min; Zhang, Bo; Wang, Yu-Zhong; Liang, Qiu-Hua

2016-01-01

Vascular calcification is an active process of osteoblastic differentiation of vascular smooth muscle cells; however, its definite mechanism remains unknown. Vinpocetine, a derivative of the alkaloid vincamine, has been demonstrated to inhibit the high glucose-induced proliferation of vascular smooth muscle cells; however, it remains unknown whether vinpocetine can affect the osteoblastic differentiation of vascular smooth muscle cells. We hereby investigated the effect of vinpocetine on vascular calcification using a beta-glycerophosphate-induced cell model. Our results showed that vinpocetine significantly reduced the osteoblast-like phenotypes of vascular smooth muscle cells including ALP activity, osteocalcin, collagen type I, Runx2 and BMP-2 expression as well as the formation of mineralized nodule. Vinpocetine, binding to translocation protein, induced phosphorylation of extracellular signal-related kinase and Akt and thus inhibited the translocation of nuclear factor-kappa B into the nucleus. Silencing of translocator protein significantly attenuated the inhibitory effect of vinpocetine on osteoblastic differentiation of vascular smooth muscle cells. Taken together, vinpocetine may be a promising candidate for the clinical therapy of vascular calcification.

Effect of critical-band smoothing of musical instrument spectral data

NASA Astrophysics Data System (ADS)

Beauchamp, James W.; Horner, Andrew B.

2005-04-01

It has been found that second-order harmonic smoothing of musical instrument spectral data can have a significant effect on timbral perception, depending on the instrument tested [McAdams et al., J. Acoust. Soc. Am. 102, 882-897 (1999)]. With critical-band smoothing, the lower harmonics, since they are in different critical bands, retain their individual amplitudes and temporal envelopes. Thus, it is hypothesized that critical-band smoothing has a lesser perceptual effect on most instrument tones than harmonic smoothing. On the other hand, upper critical bands consist of groups of harmonics. It is hypothesized that it is difficult to hear out individual harmonics within critical bands. Thus, for each band the independent harmonic temporal envelopes can be replaced by a composite rms-amplitude envelope. Spectra within bands can be replaced by time-averaged spectra. Alternatively, time-dependent amplitude versus Bark-frequency spectral envelopes can be smoothed for each individual analysis frame. Further, amplitudes can be averaged in dB or linear units. Results for various processing combinations and various musical instrument sounds will be given and demonstrated.

Research of beam smoothing technologies using CPP, SSD, and PS

NASA Astrophysics Data System (ADS)

Zhang, Rui; Su, Jingqin; Hu, Dongxia; Li, Ping; Yuan, Haoyu; Zhou, Wei; Yuan, Qiang; Wang, Yuancheng; Tian, Xiaocheng; Xu, Dangpeng; Dong, Jun; Zhu, Qihua

2015-02-01

Precise physical experiments place strict requirements on target illumination uniformity in Inertial Confinement Fusion. To obtain a smoother focal spot and suppress transverse SBS in large aperture optics, Multi-FM smoothing by spectral dispersion (SSD) was studied combined with continuous phase plate (CPP) and polarization smoothing (PS). New ways of PS are being developed to improve the laser irradiation uniformity and solve LPI problems in indirect-drive laser fusion. The near field and far field properties of beams using polarization smoothing were studied and compared, including birefringent wedge and polarization control array. As more parameters can be manipulated in a combined beam smoothing scheme, quad beam smoothing was also studies. Simulation results indicate through adjusting dispersion directions of one-dimensional (1-D) SSD beams in a quad, two-dimensional SSD can be obtained. Experiments have been done on SG-III laser facility using CPP and Multi-FM SSD. The research provides some theoretical and experimental basis for the application of CPP, SSD and PS on high-power laser facilities.

A unified framework for spiking and gap-junction interactions in distributed neuronal network simulations

PubMed Central

Hahne, Jan; Helias, Moritz; Kunkel, Susanne; Igarashi, Jun; Bolten, Matthias; Frommer, Andreas; Diesmann, Markus

2015-01-01

Contemporary simulators for networks of point and few-compartment model neurons come with a plethora of ready-to-use neuron and synapse models and support complex network topologies. Recent technological advancements have broadened the spectrum of application further to the efficient simulation of brain-scale networks on supercomputers. In distributed network simulations the amount of spike data that accrues per millisecond and process is typically low, such that a common optimization strategy is to communicate spikes at relatively long intervals, where the upper limit is given by the shortest synaptic transmission delay in the network. This approach is well-suited for simulations that employ only chemical synapses but it has so far impeded the incorporation of gap-junction models, which require instantaneous neuronal interactions. Here, we present a numerical algorithm based on a waveform-relaxation technique which allows for network simulations with gap junctions in a way that is compatible with the delayed communication strategy. Using a reference implementation in the NEST simulator, we demonstrate that the algorithm and the required data structures can be smoothly integrated with existing code such that they complement the infrastructure for spiking connections. To show that the unified framework for gap-junction and spiking interactions achieves high performance and delivers high accuracy in the presence of gap junctions, we present benchmarks for workstations, clusters, and supercomputers. Finally, we discuss limitations of the novel technology. PMID:26441628

A GPU accelerated and error-controlled solver for the unbounded Poisson equation in three dimensions

NASA Astrophysics Data System (ADS)

Exl, Lukas

2017-12-01

An efficient solver for the three dimensional free-space Poisson equation is presented. The underlying numerical method is based on finite Fourier series approximation. While the error of all involved approximations can be fully controlled, the overall computation error is driven by the convergence of the finite Fourier series of the density. For smooth and fast-decaying densities the proposed method will be spectrally accurate. The method scales with O(N log N) operations, where N is the total number of discretization points in the Cartesian grid. The majority of the computational costs come from fast Fourier transforms (FFT), which makes it ideal for GPU computation. Several numerical computations on CPU and GPU validate the method and show efficiency and convergence behavior. Tests are performed using the Vienna Scientific Cluster 3 (VSC3). A free MATLAB implementation for CPU and GPU is provided to the interested community.

Effective Algorithm for Detection and Correction of the Wave Reconstruction Errors Caused by the Tilt of Reference Wave in Phase-shifting Interferometry

NASA Astrophysics Data System (ADS)

Xu, Xianfeng; Cai, Luzhong; Li, Dailin; Mao, Jieying

2010-04-01

In phase-shifting interferometry (PSI) the reference wave is usually supposed to be an on-axis plane wave. But in practice a slight tilt of reference wave often occurs, and this tilt will introduce unexpected errors of the reconstructed object wave-front. Usually the least-square method with iterations, which is time consuming, is employed to analyze the phase errors caused by the tilt of reference wave. Here a simple effective algorithm is suggested to detect and then correct this kind of errors. In this method, only some simple mathematic operation is used, avoiding using least-square equations as needed in most methods reported before. It can be used for generalized phase-shifting interferometry with two or more frames for both smooth and diffusing objects, and the excellent performance has been verified by computer simulations. The numerical simulations show that the wave reconstruction errors can be reduced by 2 orders of magnitude.

Evaluation of gap filling skills and reading mistakes of cochlear implanted and normally hearing students.

PubMed

Çizmeci, Hülya; Çiprut, Ayça

2018-06-01

This study aimed to (1) evaluate the gap filling skills and reading mistakes of students with cochlear implants, and to (2) compare their results with those of their normal-hearing peers. The effects of implantation age and total time of cochlear implant use were analyzed in relation to the subjects' reading skills development. The study included 19 students who underwent cochlear implantation and 20 students with normal hearing, who were enrolled at the 6th to 8th grades. The subjects' ages ranged between 12 and 14 years old. Their reading skills were evaluated by using the Informal Reading Inventory. A significant relationship were found between implanted and normal-hearing students in terms of the percentages of reading error and the percentages of gap filling scores. The average order of the reading errors of students using cochlear implants was higher than that of normal-hearing students. As for the gap filling, the performances of implanted students in the passage are lower than those of their normal-hearing peers. No significant relationship was found between the variables tested in terms of age and duration of implantation on the reading performances of implanted students. Even if they were early implanted, there were significant differences in the reading performances of implanted students compared with those of their normal-hearing peers in older classes. Copyright © 2018 Elsevier B.V. All rights reserved.

The R-factor gap in macromolecular crystallography: an untapped potential for insights on accurate structures.

PubMed

Holton, James M; Classen, Scott; Frankel, Kenneth A; Tainer, John A

2014-09-01

In macromolecular crystallography, the agreement between observed and predicted structure factors (Rcryst and Rfree ) is seldom better than 20%. This is much larger than the estimate of experimental error (Rmerge ). The difference between Rcryst and Rmerge is the R-factor gap. There is no such gap in small-molecule crystallography, for which calculated structure factors are generally considered more accurate than the experimental measurements. Perhaps the true noise level of macromolecular data is higher than expected? Or is the gap caused by inaccurate phases that trap refined models in local minima? By generating simulated diffraction patterns using the program MLFSOM, and including every conceivable source of experimental error, we show that neither is the case. Processing our simulated data yielded values that were indistinguishable from those of real data for all crystallographic statistics except the final Rcryst and Rfree . These values decreased to 3.8% and 5.5% for simulated data, suggesting that the reason for high R-factors in macromolecular crystallography is neither experimental error nor phase bias, but rather an underlying inadequacy in the models used to explain our observations. The present inability to accurately represent the entire macromolecule with both its flexibility and its protein-solvent interface may be improved by synergies between small-angle X-ray scattering, computational chemistry and crystallography. The exciting implication of our finding is that macromolecular data contain substantial hidden and untapped potential to resolve ambiguities in the true nature of the nanoscale, a task that the second century of crystallography promises to fulfill. Coordinates and structure factors for the real data have been submitted to the Protein Data Bank under accession 4tws. © 2014 The Authors. FEBS Journal published by John Wiley & Sons Ltd on behalf of FEBS.

Challenge and Error: Critical Events and Attention-Related Errors

ERIC Educational Resources Information Center

Cheyne, James Allan; Carriere, Jonathan S. A.; Solman, Grayden J. F.; Smilek, Daniel

2011-01-01

Attention lapses resulting from reactivity to task challenges and their consequences constitute a pervasive factor affecting everyday performance errors and accidents. A bidirectional model of attention lapses (error [image omitted] attention-lapse: Cheyne, Solman, Carriere, & Smilek, 2009) argues that errors beget errors by generating attention…

An adaptive segment method for smoothing lidar signal based on noise estimation

NASA Astrophysics Data System (ADS)

Wang, Yuzhao; Luo, Pingping

2014-10-01

An adaptive segmentation smoothing method (ASSM) is introduced in the paper to smooth the signal and suppress the noise. In the ASSM, the noise is defined as the 3σ of the background signal. An integer number N is defined for finding the changing positions in the signal curve. If the difference of adjacent two points is greater than 3Nσ, the position is recorded as an end point of the smoothing segment. All the end points detected as above are recorded and the curves between them will be smoothed separately. In the traditional method, the end points of the smoothing windows in the signals are fixed. The ASSM creates changing end points in different signals and the smoothing windows could be set adaptively. The windows are always set as the half of the segmentations and then the average smoothing method will be applied in the segmentations. The Iterative process is required for reducing the end-point aberration effect in the average smoothing method and two or three times are enough. In ASSM, the signals are smoothed in the spacial area nor frequent area, that means the frequent disturbance will be avoided. A lidar echo was simulated in the experimental work. The echo was supposed to be created by a space-born lidar (e.g. CALIOP). And white Gaussian noise was added to the echo to act as the random noise resulted from environment and the detector. The novel method, ASSM, was applied to the noisy echo to filter the noise. In the test, N was set to 3 and the Iteration time is two. The results show that, the signal could be smoothed adaptively by the ASSM, but the N and the Iteration time might be optimized when the ASSM is applied in a different lidar.

Distinct eye movement patterns enhance dynamic visual acuity.

PubMed

Palidis, Dimitrios J; Wyder-Hodge, Pearson A; Fooken, Jolande; Spering, Miriam

2017-01-01

Dynamic visual acuity (DVA) is the ability to resolve fine spatial detail in dynamic objects during head fixation, or in static objects during head or body rotation. This ability is important for many activities such as ball sports, and a close relation has been shown between DVA and sports expertise. DVA tasks involve eye movements, yet, it is unclear which aspects of eye movements contribute to successful performance. Here we examined the relation between DVA and the kinematics of smooth pursuit and saccadic eye movements in a cohort of 23 varsity baseball players. In a computerized dynamic-object DVA test, observers reported the location of the gap in a small Landolt-C ring moving at various speeds while eye movements were recorded. Smooth pursuit kinematics-eye latency, acceleration, velocity gain, position error-and the direction and amplitude of saccadic eye movements were linked to perceptual performance. Results reveal that distinct eye movement patterns-minimizing eye position error, tracking smoothly, and inhibiting reverse saccades-were related to dynamic visual acuity. The close link between eye movement quality and DVA performance has important implications for the development of perceptual training programs to improve DVA.

Reliable and efficient a posteriori error estimation for adaptive IGA boundary element methods for weakly-singular integral equations

PubMed Central

Feischl, Michael; Gantner, Gregor; Praetorius, Dirk

2015-01-01

We consider the Galerkin boundary element method (BEM) for weakly-singular integral equations of the first-kind in 2D. We analyze some residual-type a posteriori error estimator which provides a lower as well as an upper bound for the unknown Galerkin BEM error. The required assumptions are weak and allow for piecewise smooth parametrizations of the boundary, local mesh-refinement, and related standard piecewise polynomials as well as NURBS. In particular, our analysis gives a first contribution to adaptive BEM in the frame of isogeometric analysis (IGABEM), for which we formulate an adaptive algorithm which steers the local mesh-refinement and the multiplicity of the knots. Numerical experiments underline the theoretical findings and show that the proposed adaptive strategy leads to optimal convergence. PMID:26085698

West Antarctic Balance Fluxes: Impact of Smoothing, Algorithm and Topography.

NASA Astrophysics Data System (ADS)

Le Brocq, A.; Payne, A. J.; Siegert, M. J.; Bamber, J. L.

2004-12-01

Grid-based calculations of balance flux and velocity have been widely used to understand the large-scale dynamics of ice masses and as indicators of their state of balance. This research investigates a number of issues relating to their calculation for the West Antarctic Ice Sheet (see below for further details): 1) different topography smoothing techniques; 2) different grid based flow-apportioning algorithms; 3) the source of the flow direction, whether from smoothed topography, or smoothed gravitational driving stress; 4) different flux routing techniques and 5) the impact of different topographic datasets. The different algorithms described below lead to significant differences in both ice stream margins and values of fluxes within them. This encourages caution in the use of grid-based balance flux/velocity distributions and values, especially when considering the state of balance of individual ice streams. 1) Most previous calculations have used the same numerical scheme (Budd and Warner, 1996) applied to a smoothed topography in order to incorporate the longitudinal stresses that smooth ice flow. There are two options to consider when smoothing the topography, the size of the averaging filter and the shape of the averaging function. However, this is not a physically-based approach to incorporating smoothed ice flow and also introduces significant flow artefacts when using a variable weighting function. 2) Different algorithms to apportion flow are investigated; using 4 or 8 neighbours, and apportioning flow to all down-slope cells or only 2 (based on derived flow direction). 3) A theoretically more acceptable approach of incorporating smoothed ice flow is to use the smoothed gravitational driving stress in x and y components to derive a flow direction. The flux can then be apportioned using the flow direction approach used above. 4) The original scheme (Budd and Warner, 1996) uses an elevation sort technique to calculate the balance flux contribution from all

Myosin Light Chain Kinase Is Necessary for Tonic Airway Smooth Muscle Contraction*

PubMed Central

Zhang, Wen-Cheng; Peng, Ya-Jing; Zhang, Gen-Sheng; He, Wei-Qi; Qiao, Yan-Ning; Dong, Ying-Ying; Gao, Yun-Qian; Chen, Chen; Zhang, Cheng-Hai; Li, Wen; Shen, Hua-Hao; Ning, Wen; Kamm, Kristine E.; Stull, James T.; Gao, Xiang; Zhu, Min-Sheng

2010-01-01

Different interacting signaling modules involving Ca2+/calmodulin-dependent myosin light chain kinase, Ca2+-independent regulatory light chain phosphorylation, myosin phosphatase inhibition, and actin filament-based proteins are proposed as specific cellular mechanisms involved in the regulation of smooth muscle contraction. However, the relative importance of specific modules is not well defined. By using tamoxifen-activated and smooth muscle-specific knock-out of myosin light chain kinase in mice, we analyzed its role in tonic airway smooth muscle contraction. Knock-out of the kinase in both tracheal and bronchial smooth muscle significantly reduced contraction and myosin phosphorylation responses to K+-depolarization and acetylcholine. Kinase-deficient mice lacked bronchial constrictions in normal and asthmatic airways, whereas the asthmatic inflammation response was not affected. These results indicate that myosin light chain kinase acts as a central participant in the contractile signaling module of tonic smooth muscle. Importantly, contractile airway smooth muscles are necessary for physiological and asthmatic airway resistance. PMID:20018858

How Do Simulated Error Experiences Impact Attitudes Related to Error Prevention?

PubMed

Breitkreuz, Karen R; Dougal, Renae L; Wright, Melanie C

2016-10-01

The objective of this project was to determine whether simulated exposure to error situations changes attitudes in a way that may have a positive impact on error prevention behaviors. Using a stratified quasi-randomized experiment design, we compared risk perception attitudes of a control group of nursing students who received standard error education (reviewed medication error content and watched movies about error experiences) to an experimental group of students who reviewed medication error content and participated in simulated error experiences. Dependent measures included perceived memorability of the educational experience, perceived frequency of errors, and perceived caution with respect to preventing errors. Experienced nursing students perceived the simulated error experiences to be more memorable than movies. Less experienced students perceived both simulated error experiences and movies to be highly memorable. After the intervention, compared with movie participants, simulation participants believed errors occurred more frequently. Both types of education increased the participants' intentions to be more cautious and reported caution remained higher than baseline for medication errors 6 months after the intervention. This study provides limited evidence of an advantage of simulation over watching movies describing actual errors with respect to manipulating attitudes related to error prevention. Both interventions resulted in long-term impacts on perceived caution in medication administration. Simulated error experiences made participants more aware of how easily errors can occur, and the movie education made participants more aware of the devastating consequences of errors.

A Note on the Definition of a Smooth Curve

ERIC Educational Resources Information Center

Euler, Russell; Sadek, Jawad

2005-01-01

In many elementary calculus textbooks in use today, the definition of a "smooth curve" is slightly ambiguous from the students' perspective. Even when smoothness is defined carefully, there is a shortage of relevant exercises that would serve to elaborate on related subtle points which many students may find confusing. In this article, the authors…

An approach for spherical harmonic analysis of non-smooth data

NASA Astrophysics Data System (ADS)

Wang, Hansheng; Wu, Patrick; Wang, Zhiyong

2006-12-01

A method is proposed to evaluate the spherical harmonic coefficients of a global or regional, non-smooth, observable dataset sampled on an equiangular grid. The method is based on an integration strategy using new recursion relations. Because a bilinear function is used to interpolate points within the grid cells, this method is suitable for non-smooth data; the slope of the data may be piecewise continuous, with extreme changes at the boundaries. In order to validate the method, the coefficients of an axisymmetric model are computed, and compared with the derived analytical expressions. Numerical results show that this method is indeed reasonable for non-smooth models, and that the maximum degree for spherical harmonic analysis should be empirically determined by several factors including the model resolution and the degree of non-smoothness in the dataset, and it can be several times larger than the total number of latitudinal grid points. It is also shown that this method is appropriate for the approximate analysis of a smooth dataset. Moreover, this paper provides the program flowchart and an internet address where the FORTRAN code with program specifications are made available.

Effect of the plate surface characteristics and gap height on yield stresses of a magnetorheological fluid

NASA Astrophysics Data System (ADS)

Jonkkari, I.; Kostamo, E.; Kostamo, J.; Syrjala, S.; Pietola, M.

2012-07-01

Effects of the plate material, surface roughness and measuring gap height on static and dynamic yield stresses of a magnetorheological (MR) fluid were investigated with a commercial plate-plate magnetorheometer. Magnetic and non-magnetic plates with smooth (Ra ˜ 0.3 μm) and rough (Ra ˜ 10 μm) surface finishes were used. It was shown by Hall probe measurements and finite element simulations that the use of magnetic plates or higher gap heights increases the level of magnetic flux density and changes the shape of the radial flux density profile. The yield stress increase caused by these factors was determined and subtracted from the measured values in order to examine only the effect of the wall characteristics or the gap height. Roughening of the surfaces offered a significant increase in the yield stresses for non-magnetic plates. With magnetic plates the yield stresses were higher to start with, but roughening did not increase them further. A significant part of the difference in measured stresses between rough non-magnetic and magnetic plates was caused by changes in magnetic flux density rather than by better contact of the particles to the plate surfaces. In a similar manner, an increase in gap height from 0.25 to 1.00 mm can lead to over 20% increase in measured stresses due to changes in the flux density profile. When these changes were compensated the dynamic yield stresses generally remained independent of the gap height, even in the cases where it was obvious that the wall slip was present. This suggests that with MR fluids the wall slip cannot be reliably detected by comparison of flow curves measured at different gap heights.

Exponential smoothing weighted correlations

NASA Astrophysics Data System (ADS)

Pozzi, F.; Di Matteo, T.; Aste, T.

2012-06-01

In many practical applications, correlation matrices might be affected by the "curse of dimensionality" and by an excessive sensitiveness to outliers and remote observations. These shortcomings can cause problems of statistical robustness especially accentuated when a system of dynamic correlations over a running window is concerned. These drawbacks can be partially mitigated by assigning a structure of weights to observational events. In this paper, we discuss Pearson's ρ and Kendall's τ correlation matrices, weighted with an exponential smoothing, computed on moving windows using a data-set of daily returns for 300 NYSE highly capitalized companies in the period between 2001 and 2003. Criteria for jointly determining optimal weights together with the optimal length of the running window are proposed. We find that the exponential smoothing can provide more robust and reliable dynamic measures and we discuss that a careful choice of the parameters can reduce the autocorrelation of dynamic correlations whilst keeping significance and robustness of the measure. Weighted correlations are found to be smoother and recovering faster from market turbulence than their unweighted counterparts, helping also to discriminate more effectively genuine from spurious correlations.

Gap Resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Labutti, Kurt; Foster, Brian; Lapidus, Alla

Gap Resolution is a software package that was developed to improve Newbler genome assemblies by automating the closure of sequence gaps caused by repetitive regions in the DNA. This is done by performing the follow steps:1) Identify and distribute the data for each gap in sub-projects. 2) Assemble the data associated with each sub-project using a secondary assembler, such as Newbler or PGA. 3) Determine if any gaps are closed after reassembly, and either design fakes (consensus of closed gap) for those that closed or lab experiments for those that require additional data. The software requires as input a genomemore » assembly produce by the Newbler assembler provided by Roche and 454 data containing paired-end reads.« less

Establishment of the Dual Whole Cell Recording Patch Clamp Configuration for the Measurement of Gap Junction Conductance.

PubMed

Veenstra, Richard D

2016-01-01

The development of the patch clamp technique has enabled investigators to directly measure gap junction conductance between isolated pairs of small cells with resolution to the single channel level. The dual patch clamp recording technique requires specialized equipment and the acquired skill to reliably establish gigaohm seals and the whole cell recording configuration with high efficiency. This chapter describes the equipment needed and methods required to achieve accurate measurement of macroscopic and single gap junction channel conductances. Inherent limitations with the dual whole cell recording technique and methods to correct for series access resistance errors are defined as well as basic procedures to determine the essential electrical parameters necessary to evaluate the accuracy of gap junction conductance measurements using this approach.

Induction of apoptosis by pyrrolidinedithiocarbamate and N-acetylcysteine in vascular smooth muscle cells.

PubMed

Tsai, J C; Jain, M; Hsieh, C M; Lee, W S; Yoshizumi, M; Patterson, C; Perrella, M A; Cooke, C; Wang, H; Haber, E; Schlegel, R; Lee, M E

1996-02-16

Pyrrolidinedithiocarbamate (PDTC) and N-acetylcysteine (NAC) have been used as antioxidants to prevent apoptosis in lymphocytes, neurons, and vascular endothelial cells. We report here that PDTC and NAC induce apoptosis in rat and human smooth muscle cells. In rat aortic smooth muscle cells, PDTC induced cell shrinkage, chromatin condensation, and DNA strand breaks consistent with apoptosis. In addition, overexpression of Bcl-2 suppressed vascular smooth muscle cell death caused by PDTC and NAC. The viability of rat aortic smooth muscle cells decreased within 3 h of treatment with PDTC and was reduced to 30% at 12 h. The effect of PDTC and NAC on smooth muscle cells was not species specific because PDTC and NAC both caused dose-dependent reductions in viability in rat and human aortic smooth muscle cells. In contrast, neither PDTC nor NAC reduced viability in human aortic endothelial cells. The use of antioxidants to induce apoptosis in vascular smooth muscle cells may help prevent their proliferation in arteriosclerotic lesions.

[Biomechanics and bio-energetics of smooth muscle contraction. Relation to bronchial hyperreactivity].

PubMed

Coirault, C; Blanc, F X; Chemla, D; Salmeron, S; Lecarpentier, Y

2000-06-01

Mechanical studies of isolated muscle and analysis of molecular actomyosin interactions have improved our understanding of the pathophysiology of airway smooth muscle. Mechanical properties of airway smooth muscle are similar to those of other smooth muscles. Airway smooth muscle exhibits spontaneous intrinsic tone and its maximum shortening velocity (Vmax) is 10-30 fold lower than in striated muscle. Smooth muscle myosin generates step size and elementary force per crossbridge interaction approximately similar to those of skeletal muscle myosin. Special slow cycling crossbridges, termed latch-bridges, have been attributed to myosin light chain dephosphorylation. From a mechanical point of view, it has been shown that airway hyperresponsiveness is characterized by an increased Vmax and an increased shortening capacity, with no significant change in the force-generating capacity.

Walking smoothness is associated with self-reported function after accounting for gait speed.

PubMed

Lowry, Kristin A; Vanswearingen, Jessie M; Perera, Subashan; Studenski, Stephanie A; Brach, Jennifer S

2013-10-01

Gait speed has shown to be an indicator of functional status in older adults; however, there may be aspects of physical function not represented by speed but by the quality of movement. The purpose of this study was to determine the relations between walking smoothness, an indicator of the quality of movement based on trunk accelerations, and physical function. Thirty older adults (mean age, 77.7±5.1 years) participated. Usual gait speed was measured using an instrumented walkway. Walking smoothness was quantified by harmonic ratios derived from anteroposterior, vertical, and mediolateral trunk accelerations recorded during overground walking. Self-reported physical function was recorded using the function subscales of the Late-Life Function and Disability Instrument. Anteroposterior smoothness was positively associated with all function components of the Late-Life Function and Disability Instrument, whereas mediolateral smoothness exhibited negative associations. Adjusting for gait speed, anteroposterior smoothness remained associated with the overall and lower extremity function subscales, whereas mediolateral smoothness remained associated with only the advanced lower extremity subscale. These findings indicate that walking smoothness, particularly the smoothness of forward progression, represents aspects of the motor control of walking important for physical function not represented by gait speed alone.

Research on the effects of geometrical and material uncertainties on the band gap of the undulated beam

NASA Astrophysics Data System (ADS)

Li, Yi; Xu, Yanlong

2017-09-01

Considering uncertain geometrical and material parameters, the lower and upper bounds of the band gap of an undulated beam with periodically arched shape are studied by the Monte Carlo Simulation (MCS) and interval analysis based on the Taylor series. Given the random variations of the overall uncertain variables, scatter plots from the MCS are used to analyze the qualitative sensitivities of the band gap respect to these uncertainties. We find that the influence of uncertainty of the geometrical parameter on the band gap of the undulated beam is stronger than that of the material parameter. And this conclusion is also proved by the interval analysis based on the Taylor series. Our methodology can give a strategy to reduce the errors between the design and practical values of the band gaps by improving the accuracy of the specially selected uncertain design variables of the periodical structures.

Smooth muscle tumors of soft tissue and non-uterine viscera: biology and prognosis.

PubMed

Miettinen, Markku

2014-01-01

Smooth muscle tumors are here considered an essentially dichotomous group composed of benign leiomyomas and malignant leiomyosarcomas. Soft tissue smooth muscle tumors with both atypia and mitotic activity are generally diagnosed leiomyosarcomas acknowledging potential for metastasis. However, lesions exist that cannot be comfortably placed in either category, and in such cases the designation 'smooth muscle tumor of uncertain biologic potential' is appropriate. The use of this category is often necessary with limited sampling, such as needle core biopsies. Benign smooth muscle tumors include smooth muscle hamartoma and angioleiomyoma. A specific category of leiomyomas are estrogen-receptor positive ones in women. These are similar to uterine leiomyomas and can occur anywhere in the abdomen and abdominal wall. Leiomyosarcomas can occur at any site, although are more frequent in the retroperitoneum and proximal extremities. They are recognized by likeness to smooth muscle cells but can undergo pleomorphic evolution ('dedifferentiation'). Presence of smooth muscle actin is nearly uniform and desmin-positivity usual. This and the lack of KIT expression separate leiomyosarcoma from GIST, an important problem in abdominal soft tissues. EBV-associated smooth muscle tumors are a specific subcategory occurring in AIDS or post-transplant patients. These tumors can have incomplete smooth muscle differentiation but show nuclear EBER as a diagnostic feature. In contrast to many other soft tissue tumors, genetics of smooth muscle tumors are poorly understood and such diagnostic testing is not yet generally applicable in this histogenetic group. Leiomyosarcomas are known to be genetically complex, often showing 'chaotic' karyotypes including aneuploidy or polyploidy, and no recurrent tumor-specific translocations have been detected.

Laxity Profiles in the Native and Replaced Knee-Application to Robotic-Assisted Gap-Balancing Total Knee Arthroplasty.

PubMed

Shalhoub, Sami; Moschetti, Wayne E; Dabuzhsky, Leonid; Jevsevar, David S; Keggi, John M; Plaskos, Christopher

2018-05-14

The traditional goal of the gap-balancing method in total knee arthroplasty is to create equal and symmetric knee laxity throughout the arc of flexion. The purpose of this study was to (1) quantify the laxity in the native and the replaced knee throughout the range of flexion in gap-balancing total knee arthroplasty (TKA) and (2) quantify the precision in achieving a targeted gap profile throughout flexion using a robotic-assisted technique with active ligament tensioning. Robotic-assisted, gap-balancing TKA was performed in 14 cadaver specimens. The proximal tibia was resected, and the native tibiofemoral gaps were measured using a robotic tensioner that dynamically tensioned the soft-tissue envelope throughout the arc of flexion. The femoral implant was then aligned to balance the gaps at 0° and 90° of flexion. The postoperative gaps were then measured during final trialing with the robotic tensioner and compared with the planned gaps. The native gaps increased by 3.4 ± 1.7 mm medially and 3.7 ± 2.1 mm laterally from full extension to 20° of flexion (P < .001) and then remained consistent through the remaining arc of flexion. Gap balancing after TKA produced equal gaps at 0° and 90° of flexion, but the gap laxity in midflexion was 2-4 mm greater than at 0° and 90° (P < .001). The root mean square error between the planned gaps and actual measured postoperative gaps was 1.6 mm medially and 1.7 mm laterally throughout the range of motion. Aiming for equal gaps at 0° and 90° of flexion produced equal gaps in extension and flexion with larger gaps in midflexion. Consistent soft-tissue balance to a planned gap profile could be achieved by using controlled ligament tensioning in robotic-assisted TKA. Copyright © 2018 Elsevier Inc. All rights reserved.

Calcium signaling in smooth muscle.

PubMed

Hill-Eubanks, David C; Werner, Matthias E; Heppner, Thomas J; Nelson, Mark T

2011-09-01

Changes in intracellular Ca(2+) are central to the function of smooth muscle, which lines the walls of all hollow organs. These changes take a variety of forms, from sustained, cell-wide increases to temporally varying, localized changes. The nature of the Ca(2+) signal is a reflection of the source of Ca(2+) (extracellular or intracellular) and the molecular entity responsible for generating it. Depending on the specific channel involved and the detection technology employed, extracellular Ca(2+) entry may be detected optically as graded elevations in intracellular Ca(2+), junctional Ca(2+) transients, Ca(2+) flashes, or Ca(2+) sparklets, whereas release of Ca(2+) from intracellular stores may manifest as Ca(2+) sparks, Ca(2+) puffs, or Ca(2+) waves. These diverse Ca(2+) signals collectively regulate a variety of functions. Some functions, such as contractility, are unique to smooth muscle; others are common to other excitable cells (e.g., modulation of membrane potential) and nonexcitable cells (e.g., regulation of gene expression).

Role of ROCK expression in gallbladder smooth muscle contraction.

PubMed

Wang, Bin; Ding, You-Ming; Wang, Chun-Tao; Wang, Wei-Xing

2015-08-01

Cholelithiasis is a common medical condition whose incidence rate is increasing yearly, while its pathogenesis has yet to be elucidated. The present study assessed the expression of Rho-kinase (ROCK) in gallbladder smooth muscles and its effect on the contractile function of gallbladder smooth muscles during gallstone formation. Thirty male guinea pigs were randomly divided into three groups: The control group, the gallstone model group and the fasudil interference group. The fasting volume (FV) and bile capacity of the gallbladder (FB) as well as the total cholesterol (TC) and triglyceride (TG) contents of the gallbladder bile were determined. In addition, the gallbladder was dissected to identify whether any gallstones had formed. Part of the gallbladder tissue specimens were used for immunohistochemical analysis of ROCK expression in gallbladder smooth muscles. The results showed that four guinea pigs in the model group and eight in the fasudil group displayed gallstone formation, while there was no gallstone formation in the control group. The FV and FB were significantly increased in the model and fasudil groups. Similarly, the TC and TG contents of gallbladder bile were increased in these groups. The positive expression rate of ROCK in gallbladder smooth muscles in the model and fasudil groups was significantly reduced compared with that in the control group (P<0.05). The results of the present study indicated that the reduction of ROCK expression in guinea pig gallbladder smooth muscles weakened gallbladder contraction and thereby promoted gallstone formation.

Neutrophilic infiltration within the airway smooth muscle in patients with COPD

PubMed Central

Baraldo, S; Turato, G; Badin, C; Bazzan, E; Beghe, B; Zuin, R; Calabrese, F; Casoni, G; Maestrelli, P; Papi, A; Fabbri, L; Saetta, M

2004-01-01

Background: COPD is an inflammatory disorder characterised by chronic airflow limitation, but the extent to which airway inflammation is related to functional abnormalities is still uncertain. The interaction between inflammatory cells and airway smooth muscle may have a crucial role. Methods: To investigate the microlocalisation of inflammatory cells within the airway smooth muscle in COPD, surgical specimens obtained from 26 subjects undergoing thoracotomy (eight smokers with COPD, 10 smokers with normal lung function, and eight non-smoking controls) were examined. Immunohistochemical analysis was used to quantify the number of neutrophils, macrophages, mast cells, CD4+ and CD8+ cells localised within the smooth muscle of peripheral airways. Results: Smokers with COPD had an increased number of neutrophils and CD8+ cells in the airway smooth muscle compared with non-smokers. Smokers with normal lung function also had a neutrophilic infiltration in the airway smooth muscle, but to a lesser extent. When all the subjects were analysed as one group, neutrophilic infiltration was inversely related to forced expiratory volume in 1 second (% predicted). Conclusions: Microlocalisation of neutrophils and CD8+ cells in the airway smooth muscle in smokers with COPD suggests a possible role for these cells in the pathogenesis of smoking induced airflow limitation. PMID:15047950

Decadal-scale sensitivity of Northeast Greenland ice flow to errors in surface mass balance using ISSM

NASA Astrophysics Data System (ADS)

Schlegel, N.-J.; Larour, E.; Seroussi, H.; Morlighem, M.; Box, J. E.

2013-06-01

The behavior of the Greenland Ice Sheet, which is considered a major contributor to sea level changes, is best understood on century and longer time scales. However, on decadal time scales, its response is less predictable due to the difficulty of modeling surface climate, as well as incomplete understanding of the dynamic processes responsible for ice flow. Therefore, it is imperative to understand how modeling advancements, such as increased spatial resolution or more comprehensive ice flow equations, might improve projections of ice sheet response to climatic trends. Here we examine how a finely resolved climate forcing influences a high-resolution ice stream model that considers longitudinal stresses. We simulate ice flow using a two-dimensional Shelfy-Stream Approximation implemented within the Ice Sheet System Model (ISSM) and use uncertainty quantification tools embedded within the model to calculate the sensitivity of ice flow within the Northeast Greenland Ice Stream to errors in surface mass balance (SMB) forcing. Our results suggest that the model tends to smooth ice velocities even when forced with extreme errors in SMB. Indeed, errors propagate linearly through the model, resulting in discharge uncertainty of 16% or 1.9 Gt/yr. We find that mass flux is most sensitive to local errors but is also affected by errors hundreds of kilometers away; thus, an accurate SMB map of the entire basin is critical for realistic simulation. Furthermore, sensitivity analyses indicate that SMB forcing needs to be provided at a resolution of at least 40 km.

Gap junction blockade induces apoptosis in human endometrial stromal cells.

PubMed

Yu, Jie; Berga, Sarah L; Zou, Wei; Sun, He-Ying; Johnston-MacAnanny, Erika; Yalcinkaya, Tamer; Sidell, Neil; Bagchi, Indrani C; Bagchi, Milan K; Taylor, Robert N

2014-07-01

One of the most dynamic adult human tissues is the endometrium. Through coordinated, cyclical proliferation, differentiation, leukocyte recruitment, apoptosis, and desquamation, the uterine lining is expanded and shed monthly, unless pregnancy is established. Errors in these steps potentially cause endometrial dysfunction, abnormal uterine bleeding, failed embryonic implantation, infertility, or endometrial carcinoma. Our prior studies showed that gap junctions comprised of Gap junction alpha-1 (GJA1) protein, also known as connexin 43 (CX43), subunits are critical to endometrial stromal cell differentiation. The current studies were undertaken to explore the mechanism of endometrial dysfunction when gap junction intercellular communication (GJIC) is disrupted. Gap junction blockade by two distinct GJIC inhibitors, 18α-glycyrrhetinic acid (AGA) and octanol (OcOH), suppressed proliferation and induced apoptosis in endometrial stromal cells, as manifested by reduced biomarkers of cell viability, increased TUNEL staining, caspase-3 activation, sub-G1 chromosomal DNA complement, as well as shortened telomere length. Unexpectedly, we also observed that the chemical inhibitors blocked CX43 gene expression. Moreover, when endometrial stromal cells were induced to undergo hormonal decidualization, following a 7-day exposure to 10 nM 17β-estradiol + 100 nM progesterone + 0.5 mM dibutyryl cAMP, characteristic epithelioid changes in cell shape and secretion of prolactin were blunted in the presence of AGA or OcOH, recapitulating effects of RNA interference of CX43. Our findings indicate that endometrial stromal cell proliferation and maintenance of decidualized endometrial function are GJIC-dependent, and that disruption of gap junctions induces endometrial stromal cell apoptosis. These observations may have important implications for several common clinical endometrial pathologies. © 2014 Wiley Periodicals, Inc.

Computer-enhanced laparoscopic training system (CELTS): bridging the gap.

PubMed

Stylopoulos, N; Cotin, S; Maithel, S K; Ottensmeye, M; Jackson, P G; Bardsley, R S; Neumann, P F; Rattner, D W; Dawson, S L

2004-05-01

There is a large and growing gap between the need for better surgical training methodologies and the systems currently available for such training. In an effort to bridge this gap and overcome the disadvantages of the training simulators now in use, we developed the Computer-Enhanced Laparoscopic Training System (CELTS). CELTS is a computer-based system capable of tracking the motion of laparoscopic instruments and providing feedback about performance in real time. CELTS consists of a mechanical interface, a customizable set of tasks, and an Internet-based software interface. The special cognitive and psychomotor skills a laparoscopic surgeon should master were explicitly defined and transformed into quantitative metrics based on kinematics analysis theory. A single global standardized and task-independent scoring system utilizing a z-score statistic was developed. Validation exercises were performed. The scoring system clearly revealed a gap between experts and trainees, irrespective of the task performed; none of the trainees obtained a score above the threshold that distinguishes the two groups. Moreover, CELTS provided educational feedback by identifying the key factors that contributed to the overall score. Among the defined metrics, depth perception, smoothness of motion, instrument orientation, and the outcome of the task are major indicators of performance and key parameters that distinguish experts from trainees. Time and path length alone, which are the most commonly used metrics in currently available systems, are not considered good indicators of performance. CELTS is a novel and standardized skills trainer that combines the advantages of computer simulation with the features of the traditional and popular training boxes. CELTS can easily be used with a wide array of tasks and ensures comparability across different training conditions. This report further shows that a set of appropriate and clinically relevant performance metrics can be defined and a

Determining the Optimal Values of Exponential Smoothing Constants--Does Solver Really Work?

ERIC Educational Resources Information Center

Ravinder, Handanhal V.

2013-01-01

A key issue in exponential smoothing is the choice of the values of the smoothing constants used. One approach that is becoming increasingly popular in introductory management science and operations management textbooks is the use of Solver, an Excel-based non-linear optimizer, to identify values of the smoothing constants that minimize a measure…

Errors in clinical laboratories or errors in laboratory medicine?

PubMed

Plebani, Mario

2006-01-01

Laboratory testing is a highly complex process and, although laboratory services are relatively safe, they are not as safe as they could or should be. Clinical laboratories have long focused their attention on quality control methods and quality assessment programs dealing with analytical aspects of testing. However, a growing body of evidence accumulated in recent decades demonstrates that quality in clinical laboratories cannot be assured by merely focusing on purely analytical aspects. The more recent surveys on errors in laboratory medicine conclude that in the delivery of laboratory testing, mistakes occur more frequently before (pre-analytical) and after (post-analytical) the test has been performed. Most errors are due to pre-analytical factors (46-68.2% of total errors), while a high error rate (18.5-47% of total errors) has also been found in the post-analytical phase. Errors due to analytical problems have been significantly reduced over time, but there is evidence that, particularly for immunoassays, interference may have a serious impact on patients. A description of the most frequent and risky pre-, intra- and post-analytical errors and advice on practical steps for measuring and reducing the risk of errors is therefore given in the present paper. Many mistakes in the Total Testing Process are called "laboratory errors", although these may be due to poor communication, action taken by others involved in the testing process (e.g., physicians, nurses and phlebotomists), or poorly designed processes, all of which are beyond the laboratory's control. Likewise, there is evidence that laboratory information is only partially utilized. A recent document from the International Organization for Standardization (ISO) recommends a new, broader definition of the term "laboratory error" and a classification of errors according to different criteria. In a modern approach to total quality, centered on patients' needs and satisfaction, the risk of errors and mistakes

Evolution of errors in the altimetric bathymetry model used by Google Earth and GEBCO

NASA Astrophysics Data System (ADS)

Marks, K. M.; Smith, W. H. F.; Sandwell, D. T.

2010-09-01

We analyze errors in the global bathymetry models of Smith and Sandwell that combine satellite altimetry with acoustic soundings and shorelines to estimate depths. Versions of these models have been incorporated into Google Earth and the General Bathymetric Chart of the Oceans (GEBCO). We use Japan Agency for Marine-Earth Science and Technology (JAMSTEC) multibeam surveys not previously incorporated into the models as "ground truth" to compare against model versions 7.2 through 12.1, defining vertical differences as "errors." Overall error statistics improve over time: 50th percentile errors declined from 57 to 55 to 49 m, and 90th percentile errors declined from 257 to 235 to 219 m, in versions 8.2, 11.1 and 12.1. This improvement is partly due to an increasing number of soundings incorporated into successive models, and partly to improvements in the satellite gravity model. Inspection of specific sites reveals that changes in the algorithms used to interpolate across survey gaps with altimetry have affected some errors. Versions 9.1 through 11.1 show a bias in the scaling from gravity in milliGals to topography in meters that affected the 15-160 km wavelength band. Regionally averaged (>160 km wavelength) depths have accumulated error over successive versions 9 through 11. These problems have been mitigated in version 12.1, which shows no systematic variation of errors with depth. Even so, version 12.1 is in some respects not as good as version 8.2, which employed a different algorithm.

On the thermodynamics of smooth muscle contraction

NASA Astrophysics Data System (ADS)

Stålhand, Jonas; McMeeking, Robert M.; Holzapfel, Gerhard A.

2016-09-01

Cell function is based on many dynamically complex networks of interacting biochemical reactions. Enzymes may increase the rate of only those reactions that are thermodynamically consistent. In this paper we specifically treat the contraction of smooth muscle cells from the continuum thermodynamics point of view by considering them as an open system where matter passes through the cell membrane. We systematically set up a well-known four-state kinetic model for the cross-bridge interaction of actin and myosin in smooth muscle, where the transition between each state is driven by forward and reverse reactions. Chemical, mechanical and energy balance laws are provided in local forms, while energy balance is also formulated in the more convenient temperature form. We derive the local (non-negative) production of entropy from which we deduce the reduced entropy inequality and the constitutive equations for the first Piola-Kirchhoff stress tensor, the heat flux, the ion and molecular flux and the entropy. One example for smooth muscle contraction is analyzed in more detail in order to provide orientation within the established general thermodynamic framework. In particular the stress evolution, heat generation, muscle shorting rate and a condition for muscle cooling are derived.

Notch Signaling in Vascular Smooth Muscle Cells

PubMed Central

Baeten, J.T.; Lilly, B.

2018-01-01

The Notch signaling pathway is a highly conserved pathway involved in cell fate determination in embryonic development and also functions in the regulation of physiological processes in several systems. It plays an especially important role in vascular development and physiology by influencing angiogenesis, vessel patterning, arterial/venous specification, and vascular smooth muscle biology. Aberrant or dysregulated Notch signaling is the cause of or a contributing factor to many vascular disorders, including inherited vascular diseases, such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, associated with degeneration of the smooth muscle layer in cerebral arteries. Like most signaling pathways, the Notch signaling axis is influenced by complex interactions with mediators of other signaling pathways. This complexity is also compounded by different members of the Notch family having both overlapping and unique functions. Thus, it is vital to fully understand the roles and interactions of each Notch family member in order to effectively and specifically target their exact contributions to vascular disease. In this chapter, we will review the Notch signaling pathway in vascular smooth muscle cells as it relates to vascular development and human disease. PMID:28212801

Smooth Muscle-Mediated Connective Tissue Remodeling in Pulmonary Hypertension

NASA Astrophysics Data System (ADS)

Mecham, Robert P.; Whitehouse, Loren A.; Wrenn, David S.; Parks, William C.; Griffin, Gail L.; Senior, Robert M.; Crouch, Edmond C.; Stenmark, Kurt R.; Voelkel, Norbert F.

1987-07-01

Abnormal accumulation of connective tissue in blood vessels contributes to alterations in vascular physiology associated with disease states such as hypertension and atherosclerosis. Elastin synthesis was studied in blood vessels from newborn calves with severe pulmonary hypertension induced by alveolar hypoxia in order to investigate the cellular stimuli that elicit changes in pulmonary arterial connective tissue production. A two- to fourfold increase in elastin production was observed in pulmonary artery tissue and medial smooth muscle cells from hypertensive calves. This stimulation of elastin production was accompanied by a corresponding increase in elastin messenger RNA consistent with regulation at the transcriptional level. Conditioned serum harvested from cultures of pulmonary artery smooth muscle cells isolated from hypertensive animals contained one or more low molecular weight elastogenic factors that stimulated the production of elastin in both fibroblasts and smooth muscle cells and altered the chemotactic responsiveness of fibroblasts to elastin peptides. These results suggest that connective tissue changes in the pulmonary vasculature in response to pulmonary hypertension are orchestrated by the medial smooth muscle cell through the generation of specific differentiation factors that alter both the secretory phenotype and responsive properties of surrounding cells.

Smoothed Particle Inference Analysis of SNR RCW 103

NASA Astrophysics Data System (ADS)

Frank, Kari A.; Burrows, David N.; Dwarkadas, Vikram

2016-04-01

We present preliminary results of applying a novel analysis method, Smoothed Particle Inference (SPI), to an XMM-Newton observation of SNR RCW 103. SPI is a Bayesian modeling process that fits a population of gas blobs ("smoothed particles") such that their superposed emission reproduces the observed spatial and spectral distribution of photons. Emission-weighted distributions of plasma properties, such as abundances and temperatures, are then extracted from the properties of the individual blobs. This technique has important advantages over analysis techniques which implicitly assume that remnants are two-dimensional objects in which each line of sight encompasses a single plasma. By contrast, SPI allows superposition of as many blobs of plasma as are needed to match the spectrum observed in each direction, without the need to bin the data spatially. This RCW 103 analysis is part of a pilot study for the larger SPIES (Smoothed Particle Inference Exploration of SNRs) project, in which SPI will be applied to a sample of 12 bright SNRs.

Modelling vertical error in LiDAR-derived digital elevation models

NASA Astrophysics Data System (ADS)

Aguilar, Fernando J.; Mills, Jon P.; Delgado, Jorge; Aguilar, Manuel A.; Negreiros, J. G.; Pérez, José L.

2010-01-01

A hybrid theoretical-empirical model has been developed for modelling the error in LiDAR-derived digital elevation models (DEMs) of non-open terrain. The theoretical component seeks to model the propagation of the sample data error (SDE), i.e. the error from light detection and ranging (LiDAR) data capture of ground sampled points in open terrain, towards interpolated points. The interpolation methods used for infilling gaps may produce a non-negligible error that is referred to as gridding error. In this case, interpolation is performed using an inverse distance weighting (IDW) method with the local support of the five closest neighbours, although it would be possible to utilize other interpolation methods. The empirical component refers to what is known as "information loss". This is the error purely due to modelling the continuous terrain surface from only a discrete number of points plus the error arising from the interpolation process. The SDE must be previously calculated from a suitable number of check points located in open terrain and assumes that the LiDAR point density was sufficiently high to neglect the gridding error. For model calibration, data for 29 study sites, 200×200 m in size, belonging to different areas around Almeria province, south-east Spain, were acquired by means of stereo photogrammetric methods. The developed methodology was validated against two different LiDAR datasets. The first dataset used was an Ordnance Survey (OS) LiDAR survey carried out over a region of Bristol in the UK. The second dataset was an area located at Gador mountain range, south of Almería province, Spain. Both terrain slope and sampling density were incorporated in the empirical component through the calibration phase, resulting in a very good agreement between predicted and observed data (R2 = 0.9856 ; p < 0.001). In validation, Bristol observed vertical errors, corresponding to different LiDAR point densities, offered a reasonably good fit to the predicted

Fibronectin Matrix Polymerization Regulates Smooth Muscle Cell Phenotype through a Rac1 Dependent Mechanism

PubMed Central

Shi, Feng; Long, Xiaochun; Hendershot, Allison; Miano, Joseph M.; Sottile, Jane

2014-01-01

Smooth muscle cells are maintained in a differentiated state in the vessel wall, but can be modulated to a synthetic phenotype following injury. Smooth muscle phenotypic modulation is thought to play an important role in the pathology of vascular occlusive diseases. Phenotypically modulated smooth muscle cells exhibit increased proliferative and migratory properties that accompany the downregulation of smooth muscle cell marker proteins. Extracellular matrix proteins, including fibronectin, can regulate the smooth muscle phenotype when used as adhesive substrates. However, cells produce and organize a 3-dimensional fibrillar extracellular matrix, which can affect cell behavior in distinct ways from the protomeric 2-dimensional matrix proteins that are used as adhesive substrates. We previously showed that the deposition/polymerization of fibronectin into the extracellular matrix can regulate the deposition and organization of other extracellular matrix molecules in vitro. Further, our published data show that the presence of a fibronectin polymerization inhibitor results in increased expression of smooth muscle cell differentiation proteins and inhibits vascular remodeling in vivo. In this manuscript, we used an in vitro cell culture system to determine the mechanism by which fibronectin polymerization affects smooth muscle phenotypic modulation. Our data show that fibronectin polymerization decreases the mRNA levels of multiple smooth muscle differentiation genes, and downregulates the levels of smooth muscle α-actin and calponin proteins by a Rac1-dependent mechanism. The expression of smooth muscle genes is transcriptionally regulated by fibronectin polymerization, as evidenced by the increased activity of luciferase reporter constructs in the presence of a fibronectin polymerization inhibitor. Fibronectin polymerization also promotes smooth muscle cell growth, and decreases the levels of actin stress fibers. These data define a Rac1-dependent pathway wherein

A methodology for translating positional error into measures of attribute error, and combining the two error sources

Treesearch

Yohay Carmel; Curtis Flather; Denis Dean

2006-01-01

This paper summarizes our efforts to investigate the nature, behavior, and implications of positional error and attribute error in spatiotemporal datasets. Estimating the combined influence of these errors on map analysis has been hindered by the fact that these two error types are traditionally expressed in different units (distance units, and categorical units,...

Estimating error statistics for Chambon-la-Forêt observatory definitive data

NASA Astrophysics Data System (ADS)

Lesur, Vincent; Heumez, Benoît; Telali, Abdelkader; Lalanne, Xavier; Soloviev, Anatoly

2017-08-01

We propose a new algorithm for calibrating definitive observatory data with the goal of providing users with estimates of the data error standard deviations (SDs). The algorithm has been implemented and tested using Chambon-la-Forêt observatory (CLF) data. The calibration process uses all available data. It is set as a large, weakly non-linear, inverse problem that ultimately provides estimates of baseline values in three orthogonal directions, together with their expected standard deviations. For this inverse problem, absolute data error statistics are estimated from two series of absolute measurements made within a day. Similarly, variometer data error statistics are derived by comparing variometer data time series between different pairs of instruments over few years. The comparisons of these time series led us to use an autoregressive process of order 1 (AR1 process) as a prior for the baselines. Therefore the obtained baselines do not vary smoothly in time. They have relatively small SDs, well below 300 pT when absolute data are recorded twice a week - i.e. within the daily to weekly measures recommended by INTERMAGNET. The algorithm was tested against the process traditionally used to derive baselines at CLF observatory, suggesting that statistics are less favourable when this latter process is used. Finally, two sets of definitive data were calibrated using the new algorithm. Their comparison shows that the definitive data SDs are less than 400 pT and may be slightly overestimated by our process: an indication that more work is required to have proper estimates of absolute data error statistics. For magnetic field modelling, the results show that even on isolated sites like CLF observatory, there are very localised signals over a large span of temporal frequencies that can be as large as 1 nT. The SDs reported here encompass signals of a few hundred metres and less than a day wavelengths.

Histone deacetylase 8 regulates cortactin deacetylation and contraction in smooth muscle tissues

PubMed Central

Li, Jia; Chen, Shu; Cleary, Rachel A.; Wang, Ruping; Gannon, Olivia J.; Seto, Edward

2014-01-01

Histone deacetylases (HDACs) are a family of enzymes that mediate nucleosomal histone deacetylation and gene expression. Some members of the HDAC family have also been implicated in nonhistone protein deacetylation, which modulates cell-cycle control, differentiation, and cell migration. However, the role of HDACs in smooth muscle contraction is largely unknown. Here, HDAC8 was localized both in the cytoplasm and the nucleus of mouse and human smooth muscle cells. Knockdown of HDAC8 by lentivirus-encoding HDAC8 shRNA inhibited force development in response to acetylcholine. Treatment of smooth muscle tissues with HDAC8 inhibitor XXIV (OSU-HDAC-44) induced relaxation of precontracted smooth muscle tissues. In addition, cortactin is an actin-regulatory protein that undergoes deacetylation during migration of NIH 3T3 cells. In this study, acetylcholine stimulation induced cortactin deacetylation in mouse and human smooth muscle tissues, as evidenced by immunoblot analysis using antibody against acetylated lysine. Knockdown of HDAC8 by RNAi or treatment with the inhibitor attenuated cortactin deacetylation and actin polymerization without affecting myosin activation. Furthermore, expression of a charge-neutralizing cortactin mutant inhibited contraction and actin dynamics during contractile activation. These results suggest a novel mechanism for the regulation of smooth muscle contraction. In response to contractile stimulation, HDAC8 may mediate cortactin deacetylation, which subsequently promotes actin filament polymerization and smooth muscle contraction. PMID:24920679

Efficiency and Fidelity of Human DNA Polymerases λ and β during Gap-Filling DNA Synthesis

PubMed Central

Brown, Jessica A.; Pack, Lindsey R.; Sanman, Laura E.; Suo, Zucai

2010-01-01

The base excision repair (BER) pathway coordinates the replacement of 1 to 10 nucleotides at sites of single-base lesions. This process generates DNA substrates with various gap sizes which can alter the catalytic efficiency and fidelity of a DNA polymerase during gap-filling DNA synthesis. Here, we quantitatively determined the substrate specificity and base substitution fidelity of human DNA polymerase λ (Pol λ), an enzyme proposed to support the known BER DNA polymerase β (Pol β), as it filled 1- to 10-nucleotide gaps at 1-nucleotide intervals. Pol λ incorporated a correct nucleotide with relatively high efficiency until the gap size exceeded 9 nucleotides. Unlike Pol λ, Pol β did not have an absolute threshold on gap size as the catalytic efficiency for a correct dNTP gradually decreased as the gap size increased from 2 to 10 nucleotides and then recovered for non-gapped DNA. Surprisingly, an increase in gap size resulted in lower polymerase fidelity for Pol λ, and this downregulation of fidelity was controlled by its non-enzymatic N-terminal domains. Overall, Pol λ was up to 160-fold more error-prone than Pol β, thereby suggesting Pol λ would be more mutagenic during long gap-filling DNA synthesis. In addition, dCTP was the preferred misincorporation for Pol λ and its N-terminal domain truncation mutants. This nucleotide preference was shown to be dependent upon the identity of the adjacent 5′-template base. Our results suggested that both Pol λ and Pol β would catalyze nucleotide incorporation with the highest combination of efficiency and accuracy when the DNA substrate contains a single-nucleotide gap. Thus, Pol λ, like Pol β, is better suited to catalyze gap-filling DNA synthesis during short-patch BER in vivo, although, Pol λ may play a role in long-patch BER. PMID:20961817

Quantum error correction for continuously detected errors with any number of error channels per qubit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, Charlene; Wiseman, Howard; Jacobs, Kurt

2004-08-01

It was shown by Ahn, Wiseman, and Milburn [Phys. Rev. A 67, 052310 (2003)] that feedback control could be used as a quantum error correction process for errors induced by weak continuous measurement, given one perfectly measured error channel per qubit. Here we point out that this method can be easily extended to an arbitrary number of error channels per qubit. We show that the feedback protocols generated by our method encode n-2 logical qubits in n physical qubits, thus requiring just one more physical qubit than in the previous case.

Restoring a smooth function from its noisy integrals

NASA Astrophysics Data System (ADS)

Goulko, Olga; Prokof'ev, Nikolay; Svistunov, Boris

2018-05-01

Numerical (and experimental) data analysis often requires the restoration of a smooth function from a set of sampled integrals over finite bins. We present the bin hierarchy method that efficiently computes the maximally smooth function from the sampled integrals using essentially all the information contained in the data. We perform extensive tests with different classes of functions and levels of data quality, including Monte Carlo data suffering from a severe sign problem and physical data for the Green's function of the Fröhlich polaron.

The association of cortactin with profilin-1 is critical for smooth muscle contraction.

PubMed

Wang, Ruping; Cleary, Rachel A; Wang, Tao; Li, Jia; Tang, Dale D

2014-05-16

Profilin-1 (Pfn-1) is an actin-regulatory protein that has a role in modulating smooth muscle contraction. However, the mechanisms that regulate Pfn-1 in smooth muscle are not fully understood. Here, stimulation with acetylcholine induced an increase in the association of the adapter protein cortactin with Pfn-1 in smooth muscle cells/tissues. Furthermore, disruption of the protein/protein interaction by a cell-permeable peptide (CTTN-I peptide) attenuated actin polymerization and smooth muscle contraction without affecting myosin light chain phosphorylation at Ser-19. Knockdown of cortactin by lentivirus-mediated RNAi also diminished actin polymerization and smooth muscle force development. However, cortactin knockdown did not affect myosin activation. In addition, cortactin phosphorylation has been implicated in nonmuscle cell migration. In this study, acetylcholine stimulation induced cortactin phosphorylation at Tyr-421 in smooth muscle cells. Phenylalanine substitution at this position impaired cortactin/Pfn-1 interaction in response to contractile activation. c-Abl is a tyrosine kinase that is necessary for actin dynamics and contraction in smooth muscle. Here, c-Abl silencing inhibited the agonist-induced cortactin phosphorylation and the association of cortactin with Pfn-1. Finally, treatment with CTTN-I peptide reduced airway resistance and smooth muscle hyperreactivity in a murine model of asthma. These results suggest that the interaction of cortactin with Pfn-1 plays a pivotal role in regulating actin dynamics, smooth muscle contraction, and airway hyperresponsiveness in asthma. The association of cortactin with Pfn-1 is regulated by c-Abl-mediated cortactin phosphorylation. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

The Association of Cortactin with Profilin-1 Is Critical for Smooth Muscle Contraction*

PubMed Central

Wang, Ruping; Cleary, Rachel A.; Wang, Tao; Li, Jia; Tang, Dale D.

2014-01-01

Profilin-1 (Pfn-1) is an actin-regulatory protein that has a role in modulating smooth muscle contraction. However, the mechanisms that regulate Pfn-1 in smooth muscle are not fully understood. Here, stimulation with acetylcholine induced an increase in the association of the adapter protein cortactin with Pfn-1 in smooth muscle cells/tissues. Furthermore, disruption of the protein/protein interaction by a cell-permeable peptide (CTTN-I peptide) attenuated actin polymerization and smooth muscle contraction without affecting myosin light chain phosphorylation at Ser-19. Knockdown of cortactin by lentivirus-mediated RNAi also diminished actin polymerization and smooth muscle force development. However, cortactin knockdown did not affect myosin activation. In addition, cortactin phosphorylation has been implicated in nonmuscle cell migration. In this study, acetylcholine stimulation induced cortactin phosphorylation at Tyr-421 in smooth muscle cells. Phenylalanine substitution at this position impaired cortactin/Pfn-1 interaction in response to contractile activation. c-Abl is a tyrosine kinase that is necessary for actin dynamics and contraction in smooth muscle. Here, c-Abl silencing inhibited the agonist-induced cortactin phosphorylation and the association of cortactin with Pfn-1. Finally, treatment with CTTN-I peptide reduced airway resistance and smooth muscle hyperreactivity in a murine model of asthma. These results suggest that the interaction of cortactin with Pfn-1 plays a pivotal role in regulating actin dynamics, smooth muscle contraction, and airway hyperresponsiveness in asthma. The association of cortactin with Pfn-1 is regulated by c-Abl-mediated cortactin phosphorylation. PMID:24700464

The Initiation of Smooth Pursuit is Delayed in Anisometropic Amblyopia.

PubMed

Raashid, Rana Arham; Liu, Ivy Ziqian; Blakeman, Alan; Goltz, Herbert C; Wong, Agnes M F

2016-04-01

Several behavioral studies have shown that the reaction times of visually guided movements are slower in people with amblyopia, particularly during amblyopic eye viewing. Here, we tested the hypothesis that the initiation of smooth pursuit eye movements, which are responsible for accurately keeping moving objects on the fovea, is delayed in people with anisometropic amblyopia. Eleven participants with anisometropic amblyopia and 14 visually normal observers were asked to track a step-ramp target moving at ±15°/s horizontally as quickly and as accurately as possible. The experiment was conducted under three viewing conditions: amblyopic/nondominant eye, binocular, and fellow/dominant eye viewing. Outcome measures were smooth pursuit latency, open-loop gain, steady state gain, and catch-up saccade frequency. Participants with anisometropic amblyopia initiated smooth pursuit significantly slower during amblyopic eye viewing (206 ± 20 ms) than visually normal observers viewing with their nondominant eye (183 ± 17 ms, P = 0.002). However, mean pursuit latency in the anisometropic amblyopia group during binocular and monocular fellow eye viewing was comparable to the visually normal group. Mean open-loop gain, steady state gain, and catch-up saccade frequency were similar between the two groups, but participants with anisometropic amblyopia exhibited more variable steady state gain (P = 0.045). This study provides evidence of temporally delayed smooth pursuit initiation in anisometropic amblyopia. After initiation, the smooth pursuit velocity profile in anisometropic amblyopia participants is similar to visually normal controls. This finding differs from what has been observed previously in participants with strabismic amblyopia who exhibit reduced smooth pursuit velocity gains with more catch-up saccades.

The Initiation of Smooth Pursuit is Delayed in Anisometropic Amblyopia

PubMed Central

Raashid, Rana Arham; Liu, Ivy Ziqian; Blakeman, Alan; Goltz, Herbert C.; Wong, Agnes M. F.

2016-01-01

Purpose Several behavioral studies have shown that the reaction times of visually guided movements are slower in people with amblyopia, particularly during amblyopic eye viewing. Here, we tested the hypothesis that the initiation of smooth pursuit eye movements, which are responsible for accurately keeping moving objects on the fovea, is delayed in people with anisometropic amblyopia. Methods Eleven participants with anisometropic amblyopia and 14 visually normal observers were asked to track a step-ramp target moving at ±15°/s horizontally as quickly and as accurately as possible. The experiment was conducted under three viewing conditions: amblyopic/nondominant eye, binocular, and fellow/dominant eye viewing. Outcome measures were smooth pursuit latency, open-loop gain, steady state gain, and catch-up saccade frequency. Results Participants with anisometropic amblyopia initiated smooth pursuit significantly slower during amblyopic eye viewing (206 ± 20 ms) than visually normal observers viewing with their nondominant eye (183 ± 17 ms, P = 0.002). However, mean pursuit latency in the anisometropic amblyopia group during binocular and monocular fellow eye viewing was comparable to the visually normal group. Mean open-loop gain, steady state gain, and catch-up saccade frequency were similar between the two groups, but participants with anisometropic amblyopia exhibited more variable steady state gain (P = 0.045). Conclusions This study provides evidence of temporally delayed smooth pursuit initiation in anisometropic amblyopia. After initiation, the smooth pursuit velocity profile in anisometropic amblyopia participants is similar to visually normal controls. This finding differs from what has been observed previously in participants with strabismic amblyopia who exhibit reduced smooth pursuit velocity gains with more catch-up saccades. PMID:27070109

[Research progress of larger flexion gap than extension gap in total knee arthroplasty].

PubMed

Zhang, Weisong; Hao, Dingjun

2017-05-01

To summarize the progress of larger flexion gap than extension gap in total knee arthro-plasty (TKA). The domestic and foreign related literature about larger flexion gap than extension gap in TKA, and its impact factors, biomechanical and kinematic features, and clinical results were summarized. During TKA, to adjust the relations of flexion gap and extension gap is one of the key factors of successful operation. The biomechanical, kinematic, and clinical researches show that properly larger flexion gap than extension gap can improve both the postoperative knee range of motion and the satisfaction of patients, but does not affect the stability of the knee joint. However, there are also contrary findings. So adjustment of flexion gap and extension gap during TKA is still in dispute. Larger flexion gap than extension gap in TKA is a new joint space theory, and long-term clinical efficacy, operation skills, and related complications still need further study.

A Real-Time Orbit Determination Method for Smooth Transition from Optical Tracking to Laser Ranging of Debris

PubMed Central

Li, Bin; Sang, Jizhang; Zhang, Zhongping

2016-01-01

A critical requirement to achieve high efficiency of debris laser tracking is to have sufficiently accurate orbit predictions (OP) in both the pointing direction (better than 20 arc seconds) and distance from the tracking station to the debris objects, with the former more important than the latter because of the narrow laser beam. When the two line element (TLE) is used to provide the orbit predictions, the resultant pointing errors are usually on the order of tens to hundreds of arc seconds. In practice, therefore, angular observations of debris objects are first collected using an optical tracking sensor, and then used to guide the laser beam pointing to the objects. The manual guidance may cause interrupts to the laser tracking, and consequently loss of valuable laser tracking data. This paper presents a real-time orbit determination (OD) and prediction method to realize smooth and efficient debris laser tracking. The method uses TLE-computed positions and angles over a short-arc of less than 2 min as observations in an OD process where simplified force models are considered. After the OD convergence, the OP is performed from the last observation epoch to the end of the tracking pass. Simulation and real tracking data processing results show that the pointing prediction errors are usually less than 10″, and the distance errors less than 100 m, therefore, the prediction accuracy is sufficient for the blind laser tracking. PMID:27347958

Gap Junctions

PubMed Central

Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L.; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

2013-01-01

Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1981-2035, 2012. PMID:23723031

Reprocessing the GRACE-derived gravity field time series based on data-driven method for ocean tide alias error mitigation

NASA Astrophysics Data System (ADS)

Liu, Wei; Sneeuw, Nico; Jiang, Weiping

2017-04-01

GRACE mission has contributed greatly to the temporal gravity field monitoring in the past few years. However, ocean tides cause notable alias errors for single-pair spaceborne gravimetry missions like GRACE in two ways. First, undersampling from satellite orbit induces the aliasing of high-frequency tidal signals into the gravity signal. Second, ocean tide models used for de-aliasing in the gravity field retrieval carry errors, which will directly alias into the recovered gravity field. GRACE satellites are in non-repeat orbit, disabling the alias error spectral estimation based on the repeat period. Moreover, the gravity field recovery is conducted in non-strictly monthly interval and has occasional gaps, which result in an unevenly sampled time series. In view of the two aspects above, we investigate the data-driven method to mitigate the ocean tide alias error in a post-processing mode.

Rapid Structured Volume Grid Smoothing and Adaption Technique

NASA Technical Reports Server (NTRS)

Alter, Stephen J.

2006-01-01

A rapid, structured volume grid smoothing and adaption technique, based on signal processing methods, was developed and applied to the Shuttle Orbiter at hypervelocity flight conditions in support of the Columbia Accident Investigation. Because of the fast pace of the investigation, computational aerothermodynamicists, applying hypersonic viscous flow solving computational fluid dynamic (CFD) codes, refined and enhanced a grid for an undamaged baseline vehicle to assess a variety of damage scenarios. Of the many methods available to modify a structured grid, most are time-consuming and require significant user interaction. By casting the grid data into different coordinate systems, specifically two computational coordinates with arclength as the third coordinate, signal processing methods are used for filtering the data [Taubin, CG v/29 1995]. Using a reverse transformation, the processed data are used to smooth the Cartesian coordinates of the structured grids. By coupling the signal processing method with existing grid operations within the Volume Grid Manipulator tool, problems related to grid smoothing are solved efficiently and with minimal user interaction. Examples of these smoothing operations are illustrated for reductions in grid stretching and volume grid adaptation. In each of these examples, other techniques existed at the time of the Columbia accident, but the incorporation of signal processing techniques reduced the time to perform the corrections by nearly 60%. This reduction in time to perform the corrections therefore enabled the assessment of approximately twice the number of damage scenarios than previously possible during the allocated investigation time.

Rapid Structured Volume Grid Smoothing and Adaption Technique

NASA Technical Reports Server (NTRS)

Alter, Stephen J.

2004-01-01

A rapid, structured volume grid smoothing and adaption technique, based on signal processing methods, was developed and applied to the Shuttle Orbiter at hypervelocity flight conditions in support of the Columbia Accident Investigation. Because of the fast pace of the investigation, computational aerothermodynamicists, applying hypersonic viscous flow solving computational fluid dynamic (CFD) codes, refined and enhanced a grid for an undamaged baseline vehicle to assess a variety of damage scenarios. Of the many methods available to modify a structured grid, most are time-consuming and require significant user interaction. By casting the grid data into different coordinate systems, specifically two computational coordinates with arclength as the third coordinate, signal processing methods are used for filtering the data [Taubin, CG v/29 1995]. Using a reverse transformation, the processed data are used to smooth the Cartesian coordinates of the structured grids. By coupling the signal processing method with existing grid operations within the Volume Grid Manipulator tool, problems related to grid smoothing are solved efficiently and with minimal user interaction. Examples of these smoothing operations are illustrated for reduction in grid stretching and volume grid adaptation. In each of these examples, other techniques existed at the time of the Columbia accident, but the incorporation of signal processing techniques reduced the time to perform the corrections by nearly 60%. This reduction in time to perform the corrections therefore enabled the assessment of approximately twice the number of damage scenarios than previously possible during the allocated investigation time.

Smooth random change point models.

PubMed

van den Hout, Ardo; Muniz-Terrera, Graciela; Matthews, Fiona E

2011-03-15

Change point models are used to describe processes over time that show a change in direction. An example of such a process is cognitive ability, where a decline a few years before death is sometimes observed. A broken-stick model consists of two linear parts and a breakpoint where the two lines intersect. Alternatively, models can be formulated that imply a smooth change between the two linear parts. Change point models can be extended by adding random effects to account for variability between subjects. A new smooth change point model is introduced and examples are presented that show how change point models can be estimated using functions in R for mixed-effects models. The Bayesian inference using WinBUGS is also discussed. The methods are illustrated using data from a population-based longitudinal study of ageing, the Cambridge City over 75 Cohort Study. The aim is to identify how many years before death individuals experience a change in the rate of decline of their cognitive ability. Copyright © 2010 John Wiley & Sons, Ltd.

Small Craters Engulfed by Smooth Plains

NASA Image and Video Library

2000-08-05

This double ring basin top center of image was photographed during NASA Mariner 10 second encounter and shows two craters about 30 km in diameter which have been engulfed by smooth plains on the floor of the inner ring.

Quantum error-correction failure distributions: Comparison of coherent and stochastic error models

NASA Astrophysics Data System (ADS)

Barnes, Jeff P.; Trout, Colin J.; Lucarelli, Dennis; Clader, B. D.

2017-06-01

We compare failure distributions of quantum error correction circuits for stochastic errors and coherent errors. We utilize a fully coherent simulation of a fault-tolerant quantum error correcting circuit for a d =3 Steane and surface code. We find that the output distributions are markedly different for the two error models, showing that no simple mapping between the two error models exists. Coherent errors create very broad and heavy-tailed failure distributions. This suggests that they are susceptible to outlier events and that mean statistics, such as pseudothreshold estimates, may not provide the key figure of merit. This provides further statistical insight into why coherent errors can be so harmful for quantum error correction. These output probability distributions may also provide a useful metric that can be utilized when optimizing quantum error correcting codes and decoding procedures for purely coherent errors.

Sleep deprivation as an experimental model system for psychosis: Effects on smooth pursuit, prosaccades, and antisaccades.

PubMed

Meyhöfer, Inga; Kumari, Veena; Hill, Antje; Petrovsky, Nadine; Ettinger, Ulrich

2017-04-01

Current antipsychotic medications fail to satisfactorily reduce negative and cognitive symptoms and produce many unwanted side effects, necessitating the development of new compounds. Cross-species, experimental behavioural model systems can be valuable to inform the development of such drugs. The aim of the current study was to further test the hypothesis that controlled sleep deprivation is a safe and effective model system for psychosis when combined with oculomotor biomarkers of schizophrenia. Using a randomized counterbalanced within-subjects design, we investigated the effects of 1 night of total sleep deprivation in 32 healthy participants on smooth pursuit eye movements (SPEM), prosaccades (PS), antisaccades (AS), and self-ratings of psychosis-like states. Compared with a normal sleep control night, sleep deprivation was associated with reduced SPEM velocity gain, higher saccadic frequency at 0.2 Hz, elevated PS spatial error, and an increase in AS direction errors. Sleep deprivation also increased intra-individual variability of SPEM, PS, and AS measures. In addition, sleep deprivation induced psychosis-like experiences mimicking hallucinations, cognitive disorganization, and negative symptoms, which in turn had moderate associations with AS direction errors. Taken together, sleep deprivation resulted in psychosis-like impairments in SPEM and AS performance. However, diverging somewhat from the schizophrenia literature, sleep deprivation additionally disrupted PS control. Sleep deprivation thus represents a promising but possibly unspecific experimental model that may be helpful to further improve our understanding of the underlying mechanisms in the pathophysiology of psychosis and aid the development of antipsychotic and pro-cognitive drugs.

Matrix Metalloproteinase-1 Activation Contributes to Airway Smooth Muscle Growth and Asthma Severity

PubMed Central

Naveed, Shams-un-nisa; Clements, Debbie; Jackson, David J.; Philp, Christopher; Billington, Charlotte K.; Soomro, Irshad; Reynolds, Catherine; Harrison, Timothy W.; Johnston, Sebastian L.; Shaw, Dominick E.

2017-01-01

Rationale: Matrix metalloproteinase-1 (MMP-1) and mast cells are present in the airways of people with asthma. Objectives: To investigate whether MMP-1 could be activated by mast cells and increase asthma severity. Methods: Patients with stable asthma and healthy control subjects underwent spirometry, methacholine challenge, and bronchoscopy, and their airway smooth muscle cells were grown in culture. A second asthma group and control subjects had symptom scores, spirometry, and bronchoalveolar lavage before and after rhinovirus-induced asthma exacerbations. Extracellular matrix was prepared from decellularized airway smooth muscle cultures. MMP-1 protein and activity were assessed. Measurements and Main Results: Airway smooth muscle cells generated pro–MMP-1, which was proteolytically activated by mast cell tryptase. Airway smooth muscle treated with activated mast cell supernatants produced extracellular matrix, which enhanced subsequent airway smooth muscle growth by 1.5-fold (P < 0.05), which was dependent on MMP-1 activation. In asthma, airway pro–MMP-1 was 5.4-fold higher than control subjects (P = 0.002). Mast cell numbers were associated with airway smooth muscle proliferation and MMP-1 protein associated with bronchial hyperresponsiveness. During exacerbations, MMP-1 activity increased and was associated with fall in FEV1 and worsening asthma symptoms. Conclusions: MMP-1 is activated by mast cell tryptase resulting in a proproliferative extracellular matrix. In asthma, mast cells are associated with airway smooth muscle growth, MMP-1 levels are associated with bronchial hyperresponsiveness, and MMP-1 activation are associated with exacerbation severity. Our findings suggest that airway smooth muscle/mast cell interactions contribute to asthma severity by transiently increasing MMP activation, airway smooth muscle growth, and airway responsiveness. PMID:27967204

A smoothing algorithm using cubic spline functions

NASA Technical Reports Server (NTRS)

Smith, R. E., Jr.; Price, J. M.; Howser, L. M.

1974-01-01

Two algorithms are presented for smoothing arbitrary sets of data. They are the explicit variable algorithm and the parametric variable algorithm. The former would be used where large gradients are not encountered because of the smaller amount of calculation required. The latter would be used if the data being smoothed were double valued or experienced large gradients. Both algorithms use a least-squares technique to obtain a cubic spline fit to the data. The advantage of the spline fit is that the first and second derivatives are continuous. This method is best used in an interactive graphics environment so that the junction values for the spline curve can be manipulated to improve the fit.

[Relaxant effects of protopine on smooth muscles].

PubMed

Huang, Y H; Zhang, Z Z; Jiang, J X

1991-01-01

The relaxant effects of protopine (Pro) on smooth muscles were studied by recording isotonic contraction and radioimmunoassay. Pro relaxed the contraction of rabbit thoracic aorta, mesenteric artery, portal vein and guinea pig ileum and taenia colon induced by high K+ (70 mmol.L-1). Pro also inhibited the contraction of rabbit thoracic aorta, mesenteric artery, portal vein induced by NE (0.3 mumol.L-1) and guinea pig taenia colon induced by BaCl2 (1 mmol.L-1). Pro inhibited the intracellular Ca2+ release, but did not inhibit Ca2+ influx induced by NE. These results suggested that the smooth muscle relaxant mechanism of action of Pro may be the inhibition of intracellular Ca2+ release.

Potential roles for BMP and Pax genes in the development of iris smooth muscle.

PubMed

Jensen, Abbie M

2005-02-01

The embryonic optic cup generates four types of tissue: neural retina, pigmented epithelium, ciliary epithelium, and iris smooth muscle. Remarkably little attention has focused on the development of the iris smooth muscle since Lewis ([1903] J. Am. Anat. 2:405-416) described its origins from the anterior rim of the optic cup neuroepithelium. As an initial step toward understanding iris smooth muscle development, I first determined the spatial and temporal pattern of the development of the iris smooth muscle in the chick by using the HNK1 antibody, which labels developing iris smooth muscle. HNK1 labeling shows that iris smooth muscle development is correlated in time and space with the development of the ciliary epithelial folds. Second, because neural crest is the only other neural tissue that has been shown to generate smooth muscle (Le Lievre and Le Douarin [1975] J. Embryo. Exp. Morphol. 34:125-154), I sought to determine whether iris smooth muscle development shares similarities with neural crest development. Two members of the BMP superfamily, BMP4 and BMP7, which may regulate neural crest development, are highly expressed by cells at the site of iris smooth muscle generation. Third, because humans and mice that are heterozygous for Pax6 mutations have no irides (Hill et al. [1991] Nature 354:522-525; Hanson et al. [1994] Nat. Genet. 6:168-173), I determined the expression of Pax6. I also examined the expression of Pax3 in the developing anterior optic cup. The developing iris smooth muscle coexpresses Pax6 and Pax3. I suggest that some of the eye defects caused by mutations in Pax6, BMP4, and BMP7 may be due to abnormal iris smooth muscle. Copyright 2004 Wiley-Liss, Inc.

Error coding simulations

NASA Technical Reports Server (NTRS)

Noble, Viveca K.

1993-01-01

There are various elements such as radio frequency interference (RFI) which may induce errors in data being transmitted via a satellite communication link. When a transmission is affected by interference or other error-causing elements, the transmitted data becomes indecipherable. It becomes necessary to implement techniques to recover from these disturbances. The objective of this research is to develop software which simulates error control circuits and evaluate the performance of these modules in various bit error rate environments. The results of the evaluation provide the engineer with information which helps determine the optimal error control scheme. The Consultative Committee for Space Data Systems (CCSDS) recommends the use of Reed-Solomon (RS) and convolutional encoders and Viterbi and RS decoders for error correction. The use of forward error correction techniques greatly reduces the received signal to noise needed for a certain desired bit error rate. The use of concatenated coding, e.g. inner convolutional code and outer RS code, provides even greater coding gain. The 16-bit cyclic redundancy check (CRC) code is recommended by CCSDS for error detection.

Registration of 'Newell' Smooth Bromegrass

USDA-ARS?s Scientific Manuscript database

‘Newell’ (Reg. No. CV-xxxx, PI 671851) smooth bromegrass (Bromus inermis Leyss.) is a steppe or southern type cultivar that is primarily adapted in the USA to areas north of 40o N lat. and east of 100o W long. that have 500 mm or more annual precipitation or in areas that have similar climate cond...