Science.gov

Sample records for adjustable time step

  1. Elderly Fallers Enhance Dynamic Stability Through Anticipatory Postural Adjustments during a Choice Stepping Reaction Time

    PubMed Central

    Tisserand, Romain; Robert, Thomas; Chabaud, Pascal; Bonnefoy, Marc; Chèze, Laurence

    2016-01-01

    In the case of disequilibrium, the capacity to step quickly is critical to avoid falling in elderly. This capacity can be simply assessed through the choice stepping reaction time test (CSRT), where elderly fallers (F) take longer to step than elderly non-fallers (NF). However, the reasons why elderly F elongate their stepping time remain unclear. The purpose of this study is to assess the characteristics of anticipated postural adjustments (APA) that elderly F develop in a stepping context and their consequences on the dynamic stability. Forty-four community-dwelling elderly subjects (20 F and 24 NF) performed a CSRT where kinematics and ground reaction forces were collected. Variables were analyzed using two-way repeated measures ANOVAs. Results for F compared to NF showed that stepping time is elongated, due to a longer APA phase. During APA, they seem to use two distinct balance strategies, depending on the axis: in the anteroposterior direction, we measured a smaller backward movement and slower peak velocity of the center of pressure (CoP); in the mediolateral direction, the CoP movement was similar in amplitude and peak velocity between groups but lasted longer. The biomechanical consequence of both strategies was an increased margin of stability (MoS) at foot-off, in the respective direction. By elongating their APA, elderly F use a safer balance strategy that prioritizes dynamic stability conditions instead of the objective of the task. Such a choice in balance strategy probably comes from muscular limitations and/or a higher fear of falling and paradoxically indicates an increased risk of fall. PMID:27965561

  2. The supplementary motor area contributes to the timing of the anticipatory postural adjustment during step initiation in participants with and without Parkinson’s disease

    PubMed Central

    Jacobs, Jesse V.; Lou, Jau-Shin; Kraakevik, Jeff A.; Horak, Fay B.

    2009-01-01

    The supplementary motor area is thought to contribute to the generation of anticipatory postural adjustments (which act to stabilize supporting body segments prior to movement), but its precise role remains unclear. In addition, participants with Parkinson’s disease (PD) exhibit impaired function of the supplementary motor area as well as decreased amplitudes and altered timing of the anticipatory postural adjustment during step initiation, but the contribution of the supplementary motor area to these impairments also remains unclear. To determine how the supplementary motor area contributes to generating the anticipatory postural adjustment and to the impaired anticipatory postural adjustments of participants with PD, we examined the voluntary steps of 8 participants with PD and 8 participants without PD, before and after disrupting the supplementary motor area and dorsolateral premotor cortex, in separate sessions, with 1-Hz repetitive transcranial magnetic stimulation. Both groups exhibited decreased durations of their anticipatory postural adjustments after repetitive transcranial magnetic stimulation over the supplementary motor area but not over the dorsolateral premotor cortex. Peak amplitudes of the anticipatory postural adjustments were unaffected by repetitive transcranial magnetic stimulation to either site. The symptom severity of the participants with PD positively correlated with the extent that repetitive transcranial magnetic stimulation over the supplementary motor area affected the durations of their anticipatory postural adjustments. The results suggest that the supplementary motor area contributes to the timing of the anticipatory postural adjustment and that participants with PD exhibit impaired timing of their anticipatory postural adjustments, in part, due to progressive dysfunction of circuits associated with the supplementary motor area. PMID:19665521

  3. Cortical control of anticipatory postural adjustments prior to stepping.

    PubMed

    Varghese, J P; Merino, D M; Beyer, K B; McIlroy, W E

    2016-01-28

    Human bipedal balance control is achieved either reactively or predictively by a distributed network of neural areas within the central nervous system with a potential role for cerebral cortex. While the role of the cortex in reactive balance has been widely explored, only few studies have addressed the cortical activations related to predictive balance control. The present study investigated the cortical activations related to the preparation and execution of anticipatory postural adjustment (APA) that precede a step. This study also examined whether the preparatory cortical activations related to a specific movement is dependent on the context of control (postural component vs. focal component). Ground reaction forces and electroencephalographic (EEG) data were recorded from 14 healthy adults while they performed lateral weight shift and lateral stepping with and without initially preloading their weight to the stance leg. EEG analysis revealed that there were distinct movement-related potentials (MRPs) with concurrent event-related desynchronization (ERD) of mu and beta rhythms prior to the onset of APA and also to the onset of foot-off during lateral stepping in the fronto-central cortical areas. Also, the MRPs and ERD prior to the onset of APA and onset of lateral weight shift were not significantly different suggesting the comparable cortical activations for the generation of postural and focal movements. The present study reveals the occurrence of cortical activation prior to the execution of an APA that precedes a step. Importantly, this cortical activity appears independent of the context of the movement.

  4. Retroactive Adjustment of Perceived Time

    ERIC Educational Resources Information Center

    Patel, Minal; Chait, Maria

    2011-01-01

    Accurately timing acoustic events in dynamic scenes is fundamental to scene analysis. To detect events in busy scenes, listeners must often identify a change in the "pattern" of ongoing fluctuation, resulting in many ubiquitous events being detected later than when they occurred. This raises the question of how delayed detection time affects the…

  5. Postural adjustment errors during lateral step initiation in older and younger adults.

    PubMed

    Sparto, Patrick J; Fuhrman, Susan I; Redfern, Mark S; Perera, Subashan; Richard Jennings, J; Alghwiri, Alia A; Furman, Joseph M

    2014-12-01

    The purpose was to examine age differences and varying levels of step response inhibition on the performance of a voluntary lateral step initiation task. Seventy older adults (70-94 years) and twenty younger adults (21-58 years) performed visually cued step initiation conditions based on direction and spatial location of arrows, ranging from a simple choice reaction time task to a perceptual inhibition task that included incongruous cues about which direction to step (e.g., a left pointing arrow appearing on the right side of a monitor). Evidence of postural adjustment errors and step latencies were recorded from vertical ground reaction forces exerted by the stepping leg. Compared with younger adults, older adults demonstrated greater variability in step behavior, generated more postural adjustment errors during conditions requiring inhibition, and had greater step initiation latencies that increased more than younger adults as the inhibition requirements of the condition became greater. Step task performance was related to clinical balance test performance more than executive function task performance.

  6. Anticipatory postural adjustments contribute to age-related changes in compensatory steps associated with unilateral perturbations.

    PubMed

    Hyodo, Masaki; Saito, Mayumi; Ushiba, Junichi; Tomita, Yutaka; Minami, Mihoko; Masakado, Yoshihisa

    2012-07-01

    Compensatory steps are essential for preventing falls following perturbations. This study aimed to explore age-related changes in compensatory steps to unilateral perturbations, specifically in terms of whether anticipatory postural adjustments (APAs) play a role in stabilizing lateral balance. Five young and five elderly male adults participated. The split-belt treadmill was used to provide bi- and unilateral perturbations, as forward or backward transitions, applied 10 times in random order. Backward steps evoked by unilateral forward perturbations were evaluated. We measured temporal characteristics, mediolateral (ML) center of mass (COM) motion, and ML step length of compensatory steps. Compensatory steps to unexpected perturbations showed delayed onset of foot-off (FO) and expanded lateral swing length in elderly compared to young subjects. Differences in COM motions and step width arose related to APAs. Elderly subjects showing APAs exhibited no significant differences in ML COM, ML COM velocity, or ML swing length compared to young subjects. However, elderly subjects without APAs showed significant changes toward instability in these parameters. The fact that APAs play a notable role, particularly in the elderly, in stability offers a new insight into preventing falls. However, APAs occurred in 29% of the steps of young and 35% of the steps of elderly subjects. If the occurrence of APAs in elderly people in response to compensatory steps was more frequent, fall risk would be reduced. Further studies, particularly into APA frequency, might contribute to improved intervention to prevent falls.

  7. The posterior shift anticipatory postural adjustment in choice reaction step initiation.

    PubMed

    Sun, Ruopeng; Guerra, Richard; Shea, John B

    2015-05-01

    The ability to step quickly in response to a perturbation has been shown to be critical for prevention of falls. The cognitive processing, weight shifting, and locomotion must be well timed to execute a successful step. The purpose of this study was to compare the response preparation and response execution processes between a simple (SRST) and a choice reaction stepping task (CRST). Nine healthy young subjects were recruited to participate in this study. Subjects were required to stand on a forceplate and maintain their balance, and step forward on a second forceplate with either the left or right foot after hearing an auditory tone. The center of pressure (COP) was analyzed to determine the types of anticipatory postural adjustment (APA) prior to a step. The APA phase and stepping phase timing was calculated based on the COP trajectory. Findings showed that reaction time (RT), APA phase and overall stepping latency were slower for CRST than for SRST. We also identified an intermediate type of APA response (posterior shift APA) in addition to the correct and error APA response, and found the posterior shift APA response had the fastest execution time for CRST, and may be beneficial for falls prevention.

  8. Optimal time step for incompressible SPH

    NASA Astrophysics Data System (ADS)

    Violeau, Damien; Leroy, Agnès

    2015-05-01

    A classical incompressible algorithm for Smoothed Particle Hydrodynamics (ISPH) is analyzed in terms of critical time step for numerical stability. For this purpose, a theoretical linear stability analysis is conducted for unbounded homogeneous flows, leading to an analytical formula for the maximum CFL (Courant-Friedrichs-Lewy) number as a function of the Fourier number. This gives the maximum time step as a function of the fluid viscosity, the flow velocity scale and the SPH discretization size (kernel standard deviation). Importantly, the maximum CFL number at large Reynolds number appears twice smaller than with the traditional Weakly Compressible (WCSPH) approach. As a consequence, the optimal time step for ISPH is only five times larger than with WCSPH. The theory agrees very well with numerical data for two usual kernels in a 2-D periodic flow. On the other hand, numerical experiments in a plane Poiseuille flow show that the theory overestimates the maximum allowed time step for small Reynolds numbers.

  9. Optimization Integrator for Large Time Steps.

    PubMed

    Gast, Theodore F; Schroeder, Craig; Stomakhin, Alexey; Jiang, Chenfanfu; Teran, Joseph M

    2015-10-01

    Practical time steps in today's state-of-the-art simulators typically rely on Newton's method to solve large systems of nonlinear equations. In practice, this works well for small time steps but is unreliable at large time steps at or near the frame rate, particularly for difficult or stiff simulations. We show that recasting backward Euler as a minimization problem allows Newton's method to be stabilized by standard optimization techniques with some novel improvements of our own. The resulting solver is capable of solving even the toughest simulations at the [Formula: see text] frame rate and beyond. We show how simple collisions can be incorporated directly into the solver through constrained minimization without sacrificing efficiency. We also present novel penalty collision formulations for self collisions and collisions against scripted bodies designed for the unique demands of this solver. Finally, we show that these techniques improve the behavior of Material Point Method (MPM) simulations by recasting it as an optimization problem.

  10. Discontinuation of data processing step: Salt adjustment on designated foods likely to be home prepared

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this report is to describe (a) the basis for and implementation of a data processing step called salt adjustment that was performed on designated foods in USDA dietary intake surveys from 1985 through 2008, (b) the rationale for discontinuing the step, and (c) the impact and implica...

  11. An automatic step adjustment method for average power analysis technique used in fiber amplifiers

    NASA Astrophysics Data System (ADS)

    Liu, Xue-Ming

    2006-04-01

    An automatic step adjustment (ASA) method for average power analysis (APA) technique used in fiber amplifiers is proposed in this paper for the first time. In comparison with the traditional APA technique, the proposed method has suggested two unique merits such as a higher order accuracy and an ASA mechanism, so that it can significantly shorten the computing time and improve the solution accuracy. A test example demonstrates that, by comparing to the APA technique, the proposed method increases the computing speed by more than a hundredfold under the same errors. By computing the model equations of erbium-doped fiber amplifiers, the numerical results show that our method can improve the solution accuracy by over two orders of magnitude at the same amplifying section number. The proposed method has the capacity to rapidly and effectively compute the model equations of fiber Raman amplifiers and semiconductor lasers.

  12. Fuel injection pump with adjustable timing

    SciTech Connect

    Nakamura, H.; Abe, N.

    1987-04-28

    A fuel injection pump is described comprising: a pump body; a plunger disposed in the pump body for reciprocating within the pump body; and a pre-stroke adjusting mechanism disposed in the pump body and operatively connected with the plunger for adjusting an effective pre-stroke of the plunger.

  13. Do centrally programmed anticipatory postural adjustments in fast stepping affect performance of an associated "touche" movement?

    PubMed

    Do, M C; Yiou, E

    1999-12-01

    Ensuring maximum speed in executing a sequence of two voluntary movements requires the second movement to be triggered only after some delay. This is due to the existence of a "relative refractory period." If the second movement is initiated during the refractory period, its speed decreases (movement time increases). In the present study we tested the existence of a refractory period during the execution of a sequence of movements involving both the upper and the lower limbs. More precisely, we examined whether the maximal speed of the touche fencing movement is affected by the anticipatory postural adjustments (APA) preceding a voluntary lunge. The touche and the lunge are similar to a pointing task and a stepping forward movement, respectively. touche consists of hitting a target with a foil at maximal velocity. The results show that (a) when the touche was initiated prior to the onset of the APA of the lunge, the maximal foil velocity remains similar to that of an isolated touche, and (b) when the touche is initiated during the development of the APA of the lunge, the maximal foil velocity is lower than in the isolated touche. Furthermore, the maximal foil velocity decreases with the temporal progression of the APA and reaches its minimal value when initiated at the time of voluntary lunge execution ('foot off'). The discussion suggests that the centrally programmed APA that are elicited in the stepping forward movement induces a refractory period which affects performance of the pointing task.

  14. Modulation of proprioceptive inflow when initiating a step influences postural adjustments.

    PubMed

    Ruget, Hélène; Blouin, Jean; Coyle, Thelma; Mouchnino, Laurence

    2010-03-01

    A synergistic inclination of the whole body towards the supporting leg is required when producing a stepping movement. It serves to shift the centre of mass towards the stance foot. While the importance of sensory information in the setting of this postural adjustment is undisputed, it is currently unknown the extent to which proprioceptive afferences (Ia) give rise to postural regulation during stepping movement when the availability of other sensory information relying on static linear acceleration (gravity) is no longer sensed in microgravity. We tested this possibility asking subjects to step forward with their eyes closed in normo- and microgravity environments. At the onset of the stepping movement, we vibrated the ankle muscles acting in the lateral direction to induce modification of the afferent inflow (Ia fibres). Vibration-evoked movement (perceived movement) was in the same direction as the forthcoming body shift towards the supporting side (current movement). A control condition was performed without vibration. In both environments, when vibration was applied, the hip shift towards the supporting side decreased. These postural modifications occurred, however, earlier in normogravity before initiating the stepping movement than in microgravity (i.e. during the completion of the stepping movement). Our results suggest that proprioceptive information induced by vibration and afferent inflow related to body movement exaggerated sense of movement. This biased perception led to the postural adjustment decrease. We propose that in both environments, proprioceptive inflow enables the subject to scale the postural adjustments, provided that body motion-induced afferences are present to activate this postural control.

  15. A ’Smart’ Molecular Sieve Oxygen Concentrator with Continuous Cycle Time Adjustment.

    DTIC Science & Technology

    1996-04-01

    A ’smart’ molecular sieve oxygen concentrator (MSOC) is controlled by a set of computer algorithms . The ’smart’ system automatically adjusts...determine if concentrator performance could be controlled by computer algorithms which continuously adjust concentrator cycle time. A two-bed... Computer algorithms or decision process were developed which allowed the software to control concentrator cycle time. Step changes in product flow from 5

  16. Time to pause before the next step

    SciTech Connect

    Siemon, R.E.

    1998-12-31

    Many scientists, who have staunchly supported ITER for years, are coming to realize it is time to further rethink fusion energy`s development strategy. Specifically, as was suggested by Grant Logan and Dale Meade, and in keeping with the restructuring of 1996, a theme of better, cheaper, faster fusion would serve the program more effectively than ``demonstrating controlled ignition...and integrated testing of the high-heat-flux and nuclear components required to utilize fusion energy...`` which are the important ingredients of ITER`s objectives. The author has personally shifted his view for a mixture of technical and political reasons. On the technical side, he senses that through advanced tokamak research, spherical tokamak research, and advanced stellarator work, scientists are coming to a new understanding that might make a burning-plasma device significantly smaller and less expensive. Thus waiting for a few years, even ten years, seems prudent. Scientifically, there is fascinating physics to be learned through studies of burning plasma on a tokamak. And clearly if one wishes to study burning plasma physics in a sustained plasma, there is no other configuration with an adequate database on which to proceed. But what is the urgency of moving towards an ITER-like step focused on burning plasma? Some of the arguments put forward and the counter arguments are discussed here.

  17. Adjustable microstep-driven system of the step motor controlled by a single-chip computer

    NASA Astrophysics Data System (ADS)

    Wang, Jinghui; Mei, Anhua

    1994-03-01

    This paper presents the frequency-fixing pulse width modulation and adjustable microstep- driven system of a step motor controlled by the MCS-51 single-chip computer. The system uses single-voltage driving. The proprietary software is configured in the system. On the same supporting hardware, the numbers of the microstep can be changed from zero to 255 by operating the keyboard. The rotating speed, direction, and displacement can be controlled directly. The system applies the technology of the digital frequency-fixing PWM and the feedback control, of the microcurrent for electromagnetic noise elimination and low power losses. The curve of the experiment proves that the system has good quality.

  18. Insect–computer hybrid legged robot with user-adjustable speed, step length and walking gait

    PubMed Central

    Cao, Feng; Zhang, Chao; Choo, Hao Yu

    2016-01-01

    We have constructed an insect–computer hybrid legged robot using a living beetle (Mecynorrhina torquata; Coleoptera). The protraction/retraction and levation/depression motions in both forelegs of the beetle were elicited by electrically stimulating eight corresponding leg muscles via eight pairs of implanted electrodes. To perform a defined walking gait (e.g. gallop), different muscles were individually stimulated in a predefined sequence using a microcontroller. Different walking gaits were performed by reordering the applied stimulation signals (i.e. applying different sequences). By varying the duration of the stimulation sequences, we successfully controlled the step frequency and hence the beetle's walking speed. To the best of our knowledge, this paper presents the first demonstration of living insect locomotion control with a user-adjustable walking gait, step length and walking speed. PMID:27030043

  19. Insect-computer hybrid legged robot with user-adjustable speed, step length and walking gait.

    PubMed

    Cao, Feng; Zhang, Chao; Choo, Hao Yu; Sato, Hirotaka

    2016-03-01

    We have constructed an insect-computer hybrid legged robot using a living beetle (Mecynorrhina torquata; Coleoptera). The protraction/retraction and levation/depression motions in both forelegs of the beetle were elicited by electrically stimulating eight corresponding leg muscles via eight pairs of implanted electrodes. To perform a defined walking gait (e.g., gallop), different muscles were individually stimulated in a predefined sequence using a microcontroller. Different walking gaits were performed by reordering the applied stimulation signals (i.e., applying different sequences). By varying the duration of the stimulation sequences, we successfully controlled the step frequency and hence the beetle's walking speed. To the best of our knowledge, this paper presents the first demonstration of living insect locomotion control with a user-adjustable walking gait, step length and walking speed.

  20. Discontinuous Galerkin Methods and Local Time Stepping for Wave Propagation

    SciTech Connect

    Grote, M. J.; Mitkova, T.

    2010-09-30

    Locally refined meshes impose severe stability constraints on explicit time-stepping methods for the numerical simulation of time dependent wave phenomena. To overcome that stability restriction, local time-stepping methods are developed, which allow arbitrarily small time steps precisely where small elements in the mesh are located. When combined with a discontinuous Galerkin finite element discretization in space, which inherently leads to a diagonal mass matrix, the resulting numerical schemes are fully explicit. Starting from the classical Adams-Bashforth multi-step methods, local time stepping schemes of arbitrarily high accuracy are derived. Numerical experiments validate the theory and illustrate the usefulness of the proposed time integration schemes.

  1. Anticipatory postural adjustments during lateral step motion in patients with hip osteoarthritis.

    PubMed

    Tateuchi, Hiroshige; Ichihashi, Noriaki; Shinya, Masahiro; Oda, Shingo

    2011-02-01

    Patients with hip osteoarthritis (OA) have difficulty with mediolateral postural control. Since the symptom of hip OA includes joint pain, which mostly occurs upon initial movement, patients with hip OA might have disabling problems with movement initiation. This study aimed to identify the movement strategy during the anticipatory postural adjustments in the lateral step motion in patients with hip OA. We studied 18 female subjects with unilateral hip OA and 10 healthy subjects, and measured temporal, kinetic, and kinematic variables. Patients with hip OA required a longer duration of anticipation phase than the control subjects, the total duration of lateral stepping was not different between the groups. Displacement of the center of mass to the supporting (affected) side during the anticipation phase was not different between the two groups. These findings suggest that, in patients with hip OA, the center of mass slowly moved to the affected side. Furthermore, patients with hip OA showed greater shift of the trunk to the supporting side than did the control subjects. These movement characteristics might contribute to the achievement of both protection of the affected hip joint and quickness in the subsequent lateral step in patients with hip OA.

  2. Collocation and Galerkin Time-Stepping Methods

    NASA Technical Reports Server (NTRS)

    Huynh, H. T.

    2011-01-01

    We study the numerical solutions of ordinary differential equations by one-step methods where the solution at tn is known and that at t(sub n+1) is to be calculated. The approaches employed are collocation, continuous Galerkin (CG) and discontinuous Galerkin (DG). Relations among these three approaches are established. A quadrature formula using s evaluation points is employed for the Galerkin formulations. We show that with such a quadrature, the CG method is identical to the collocation method using quadrature points as collocation points. Furthermore, if the quadrature formula is the right Radau one (including t(sub n+1)), then the DG and CG methods also become identical, and they reduce to the Radau IIA collocation method. In addition, we present a generalization of DG that yields a method identical to CG and collocation with arbitrary collocation points. Thus, the collocation, CG, and generalized DG methods are equivalent, and the latter two methods can be formulated using the differential instead of integral equation. Finally, all schemes discussed can be cast as s-stage implicit Runge-Kutta methods.

  3. Neural Basis of Adaptive Response Time Adjustment during Saccade Countermanding

    PubMed Central

    Pouget, Pierre; Logan, Gordon D.; Palmeri, Thomas J.; Boucher, Leanne; Paré, Martin; Schall, Jeffrey D.

    2011-01-01

    Humans and macaque monkeys adjust their response time adaptively in stop signal (countermanding) tasks, responding slower after stop-signal trials than after control trials with no stop signal. We investigated the neural mechanism underlying this adaptive response time adjustment in macaque monkeys performing a saccade countermanding task. Earlier research showed that movements are initiated when the random accumulation of presaccadic movement-related activity reaches a fixed threshold. We found that a systematic delay in response time after stop signal trials was accomplished not through a change of threshold, baseline, or accumulation rate, but instead through a change in the time when activity first began to accumulate. The neurons underlying movement initiation have been identified with mathematical accumulator models of response time performance. Therefore, this new result provides surprising new insights into the neural instantiation of stochastic accumulator models and the mechanisms through which executive control can be exerted. PMID:21880921

  4. A Robust Diffusion Estimation Algorithm with Self-Adjusting Step-Size in WSNs.

    PubMed

    Shao, Xiaodan; Chen, Feng; Ye, Qing; Duan, Shukai

    2017-04-10

    In wireless sensor networks (WSNs), each sensor node can estimate the global parameter from the local data in a distributed manner. This paper proposed a robust diffusion estimation algorithm based on a minimum error entropy criterion with a self-adjusting step-size, which are referred to as the diffusion MEE-SAS (DMEE-SAS) algorithm. The DMEE-SAS algorithm has a fast speed of convergence and is robust against non-Gaussian noise in the measurements. The detailed performance analysis of the DMEE-SAS algorithm is performed. By combining the DMEE-SAS algorithm with the diffusion minimum error entropy (DMEE) algorithm, an Improving DMEE-SAS algorithm is proposed for a non-stationary environment where tracking is very important. The Improving DMEE-SAS algorithm can avoid insensitivity of the DMEE-SAS algorithm due to the small effective step-size near the optimal estimator and obtain a fast convergence speed. Numerical simulations are given to verify the effectiveness and advantages of these proposed algorithms.

  5. Reciprocal Relations between Children's Sleep and Their Adjustment over Time

    ERIC Educational Resources Information Center

    Kelly, Ryan J.; El-Sheikh, Mona

    2014-01-01

    Child sleep and adjustment research with community samples is on the rise with a recognized need of explicating this association. We examined reciprocal relations between children's sleep and their internalizing and externalizing symptoms using 3 waves of data spanning 5 years. Participants included 176 children at Time 1 (M = 8.68 years; 69%…

  6. Hydrologic consistency analysed through modeling at multiple time steps: does hydrological model performance benefit from finer time step information?

    NASA Astrophysics Data System (ADS)

    Ficchi, Andrea; Perrin, Charles; Andréassian, Vazken

    2015-04-01

    We investigate the operational utility of fine time step hydro-climatic information using a large catchment data set. The originality of this data set lies in the availability of precipitation data from the 6-minute rain gauges of Météo-France, and in the size of the catchment set (217 French catchments in total). The rainfall-runoff model used (GR4) has been adapted to hourly and sub-hourly time steps (up to 6-minute) from the daily time step version (Perrin et al., 2003). The model is applied at different time steps ranging from 6-minute to 1 day (6-, 12-, 30-minute, 1-, 3-, 6-, 12-hour and 1 day) and the evolution of model performance for each catchment is evaluated at the daily time step by aggregation of model outputs. Three classes of behavior are found according to the trend of model performance as the time step becomes finer: (i) catchments presenting an improvement of model performance; (ii) catchments with a model performance insensitive to the time step; (iii) catchments for which the performance even deteriorates as the time step becomes finer. The reasons behind these different trends are investigated from a hydrological point of view, by relating the model sensitivity to data at finer time step to catchment descriptors. References: Perrin, C., C. Michel and V. Andréassian (2003), "Improvement of a parsimonious model for streamflow simulation", Journal of Hydrology, 279(1-4): 275-289.

  7. Diesel engine fuel injection pump capable of injection timing adjustment

    SciTech Connect

    Wakasa, S.; Okazaki, T.

    1987-12-15

    A diesel engine fuel injection pump capable of injection timing adjustment is described comprising: (a) housing means; (b) a plunger assembly reciprocably mounted within the housing means and defining a pumping chamber therein; (c) the housing means having defined therein a fuel inlet port to the pumping chamber in a predetermined position in the longitudinal direction of the pumping chamber; (d) drive means for reciprocably moving the plunger assembly within the pumping chamber between a first extreme position; (e) the plunger assembly being formed of at least two transversely split segments movable toward and away from each other within limits and including resilient means biasing the segments of the plunger assembly toward each other; and (f) the housing means further including a timing fluid inlet port for introduction of a timing fluid under variable pressure between the segments of the plunger assembly to move the plunger assembly segments away from each other to an extent that timing fluid pressure is counterbalanced by force of the resilient means for controllably varying the distance therebetween and, in consequence, for varying the prestroke of the plunger assembly solely in response to variation of the timing fluid pressure to effect adjustment of injection timing.

  8. Effect of Time Step On Atmospheric Model Systematic Errors

    NASA Astrophysics Data System (ADS)

    Williamson, D. L.

    Semi-Lagrangian approximations are becoming more common in operational Numer- ical Weather Prediction models because of the efficiency allowed by their long time steps. The early work that demonstrated that semi-Lagrangian forecasts were compa- rable to Eulerian in accuracy were based on mid-latitude short-range forecasts which were dominated by dynamical processes. These indicated no significant loss of accu- racy with semi-Lagrangian approximations and long time steps. Today, subgrid-scale parameterizations play a larger role in even short range forecasts. While not ignored, the effect of a longer time step on the parameterizations has been less thoroughly stud- ied. We present results from the NCAR CCM3 that indicate that the systematic errors in tropical precipitation patterns can depend on the time step. The actual dependency depends on the parameterization suite of the model. We identify the dependency in aqua-planet integrations. With the CCM3 parameterization suite, longer time steps re- sult in double precipitation maxima straddling the SST maximum while shorter time steps result in a single precipitation maximum over the SST maximum. Other param- eterization suites behave differently. The cause of the dependency will be discussed.

  9. Long-term planetary integration with individual time steps

    NASA Astrophysics Data System (ADS)

    Saha, Prasenjit; Tremaine, Scott

    1994-11-01

    We describe an algorithm for long-term planetary orbit integrations, including the dominant post-Newtonian effects, that employs individual time steps for each planet. The algorithm is symplectic and exhibits short-term errors that are O(epsilon(Omega2)(tau 2) where tau is the time step, Omega is a typical orbital frequency, and epsilon much less than 1 is a typical planetary mass in solar units. By a special starting procedure long-term errors over an integration interval T can be reduced to O(epsilon2(Omega3)(tau2)T. A sample 0.8 Myr integration of the nine planets illustrates that Pluto can have a time step more than 100 times Mercury's, without dominating the positional error. Our algorithm is applicable to other N-body systems.

  10. Newmark local time stepping on high-performance computing architectures

    NASA Astrophysics Data System (ADS)

    Rietmann, Max; Grote, Marcus; Peter, Daniel; Schenk, Olaf

    2017-04-01

    In multi-scale complex media, finite element meshes often require areas of local refinement, creating small elements that can dramatically reduce the global time-step for wave-propagation problems due to the CFL condition. Local time stepping (LTS) algorithms allow an explicit time-stepping scheme to adapt the time-step to the element size, allowing near-optimal time-steps everywhere in the mesh. We develop an efficient multilevel LTS-Newmark scheme and implement it in a widely used continuous finite element seismic wave-propagation package. In particular, we extend the standard LTS formulation with adaptations to continuous finite element methods that can be implemented very efficiently with very strong element-size contrasts (more than 100x). Capable of running on large CPU and GPU clusters, we present both synthetic validation examples and large scale, realistic application examples to demonstrate the performance and applicability of the method and implementation on thousands of CPU cores and hundreds of GPUs.

  11. A properly adjusted forage harvester can save time and money

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A properly adjusted forage harvester can save fuel and increase the realizable milk per ton of your silage. This article details the adjustments necessary to minimize energy while maximizing productivity and forage quality....

  12. Manual for implementing a Shared Time Engineering Program (STEP) September 1980 through September 1983

    NASA Astrophysics Data System (ADS)

    Aronoff, H. I.; Leslie, J. J.; Mittleman, A. N.; Holt, S.

    1983-11-01

    This manual describes a Shared Time Engineering Program (STEP) conducted by the New England Apparel Manufacturers Association (NEAMA) headquartered in Fall River Massachusetts, and funded by the Office of Trade Adjustment Assistance of the U.S. Department of Commerce. It is addressed to industry association executives, industrial engineers and others interested in examining an innovative model of industrial engineering assistance to small plants which might be adapted to their particular needs.

  13. Smart phone as a tool for measuring anticipatory postural adjustments in healthy subjects, a step toward more personalized healthcare.

    PubMed

    Rigoberto, Martinez M; Toshiyo, Tamura; Masaki, Sekine

    2010-01-01

    We present a study on using a smart phone as a tool to evaluate anticipatory postural adjustments (APA) before the beginning of normal gait in healthy subjects. The results show a significantly lower amplitude of anticipatory postural adjustments in the mediolateral axis (ML) when subjects used the non-dominant leg for the first step compared with the amplitude when using the dominant leg. The use of smart phones as a tool for measuring APA enables more personalized and active healthcare for the population without the necessity of their buying or carrying other devices.

  14. A step in time: Changes in standard-frequency and time-signal broadcasts, 1 January 1972

    NASA Technical Reports Server (NTRS)

    Chi, A. R.; Fosque, H. S.

    1973-01-01

    An improved coordinated universal time (UTC) system has been adopted by the International Radio Consultative Committee. It was implemented internationally by the standard-frequency and time-broadcast stations on 1 Jan. 1972. The new UTC system eliminates the frequency offset of 300 parts in 10 to the 10th power between the old UTC and atomic time, thus making the broadcast time interval (the UTC second) constant and defined by the resonant frequency of cesium atoms. The new time scale is kept in synchronism with the rotation of the Earth within plus or minus 0.7 s by step-time adjustments of exactly 1 s, when needed. A time code has been added to the disseminated time signals to permit universal time to be obtained from the broadcasts to the nearest 0.1 s for users requiring such precision. The texts of the International Radio Consultative Committee recommendation and report to implement the new UTC system are given. The coding formats used by various standard time broadcast services to transmit the difference between the universal time (UT1) and the UTC are also given. For users' convenience, worldwide primary VLF and HF transmissions stations, frequencies, and schedules of time emissions are also included. Actual time-step adjustments made by various stations on 1 Jan. 1972, are provided for future reference.

  15. Split-Step Timing of Professional and Junior Tennis Players

    PubMed Central

    Leskosek, Bojan; Filipcic, Tjasa

    2017-01-01

    Abstract The purpose of the study was to determine the timing of a split-step in three categories of tennis players in four groups of strokes. Subjects were divided into three groups: male and female junior, and male professional tennis players. During two tournaments, all matches were recorded with two fixed video cameras. For every stroke, the timing of the split-step between the opponent’s impact point when hitting the ball and the player’s split-step was measured. A two-way analysis of variance (ANOVA) was used to determine the differences between groups of strokes, players and the interaction Player x Stroke Group. A Tukey post-hoc test was employed to determine specific differences. The results revealed differences between players in detecting the opponent’s movement, stroke and ball flight, which were reflected in different split-step timings. Each tennis player has his/her own timing mechanism which they adapt to various game situations. Response times differ significantly depending on the game situation. On average, they are the lowest in the serve, and then gradually rise from the return of the serve to baseline game, reaching the highest values in specific game situations. Players react faster in the first serve than in the second one and in the return of the serve, the response times are lower after the return of the second serve PMID:28210342

  16. Short‐term time step convergence in a climate model

    PubMed Central

    Rasch, Philip J.; Taylor, Mark A.; Jablonowski, Christiane

    2015-01-01

    Abstract This paper evaluates the numerical convergence of very short (1 h) simulations carried out with a spectral‐element (SE) configuration of the Community Atmosphere Model version 5 (CAM5). While the horizontal grid spacing is fixed at approximately 110 km, the process‐coupling time step is varied between 1800 and 1 s to reveal the convergence rate with respect to the temporal resolution. Special attention is paid to the behavior of the parameterized subgrid‐scale physics. First, a dynamical core test with reduced dynamics time steps is presented. The results demonstrate that the experimental setup is able to correctly assess the convergence rate of the discrete solutions to the adiabatic equations of atmospheric motion. Second, results from full‐physics CAM5 simulations with reduced physics and dynamics time steps are discussed. It is shown that the convergence rate is 0.4—considerably slower than the expected rate of 1.0. Sensitivity experiments indicate that, among the various subgrid‐scale physical parameterizations, the stratiform cloud schemes are associated with the largest time‐stepping errors, and are the primary cause of slow time step convergence. While the details of our findings are model specific, the general test procedure is applicable to any atmospheric general circulation model. The need for more accurate numerical treatments of physical parameterizations, especially the representation of stratiform clouds, is likely common in many models. The suggested test technique can help quantify the time‐stepping errors and identify the related model sensitivities. PMID:27660669

  17. Accuracy of Pedometer Steps and Time for Youth with Disabilities

    ERIC Educational Resources Information Center

    Beets, Michael W.; Combs, Cindy; Pitetti, Kenneth H.; Morgan, Melinda; Bryan, Rebecca R.; Foley, John T.

    2007-01-01

    The purpose of the study was to examine the accuracy of pedometer steps and activity time (Walk4Life, WL) for youth with developmental disabilities. Eighteen youth (11 girls, 7 boys) 4-14 years completed six 80-meter self-paced walking trials while wearing a pedometer at five waist locations (front right, front left, back right, back left, middle…

  18. Accurate and stable time stepping in ice sheet modeling

    NASA Astrophysics Data System (ADS)

    Cheng, Gong; Lötstedt, Per; von Sydow, Lina

    2017-01-01

    In this paper we introduce adaptive time step control for simulation of the evolution of ice sheets. The discretization error in the approximations is estimated using "Milne's device" by comparing the result from two different methods in a predictor-corrector pair. Using a predictor-corrector pair the expensive part of the procedure, the solution of the velocity and pressure equations, is performed only once per time step and an estimate of the local error is easily obtained. The stability of the numerical solution is maintained and the accuracy is controlled by keeping the local error below a given threshold using PI-control. Depending on the threshold, the time step Δt is bound by stability requirements or accuracy requirements. Our method takes a shorter Δt than an implicit method but with less work in each time step and the solver is simpler. The method is analyzed theoretically with respect to stability and applied to the simulation of a 2D ice slab and a 3D circular ice sheet. The stability bounds in the experiments are explained by and agree well with the theoretical results.

  19. Adaptive time steps in trajectory surface hopping simulations

    NASA Astrophysics Data System (ADS)

    Spörkel, Lasse; Thiel, Walter

    2016-05-01

    Trajectory surface hopping (TSH) simulations are often performed in combination with active-space multi-reference configuration interaction (MRCI) treatments. Technical problems may arise in such simulations if active and inactive orbitals strongly mix and switch in some particular regions. We propose to use adaptive time steps when such regions are encountered in TSH simulations. For this purpose, we present a computational protocol that is easy to implement and increases the computational effort only in the critical regions. We test this procedure through TSH simulations of a GFP chromophore model (OHBI) and a light-driven rotary molecular motor (F-NAIBP) on semiempirical MRCI potential energy surfaces, by comparing the results from simulations with adaptive time steps to analogous ones with constant time steps. For both test molecules, the number of successful trajectories without technical failures rises significantly, from 53% to 95% for OHBI and from 25% to 96% for F-NAIBP. The computed excited-state lifetime remains essentially the same for OHBI and increases somewhat for F-NAIBP, and there is almost no change in the computed quantum efficiency for internal rotation in F-NAIBP. We recommend the general use of adaptive time steps in TSH simulations with active-space CI methods because this will help to avoid technical problems, increase the overall efficiency and robustness of the simulations, and allow for a more complete sampling.

  20. 4 Steps for Redesigning Time for Student and Teacher Learning

    ERIC Educational Resources Information Center

    Nazareno, Lori

    2017-01-01

    Everybody complains about a lack of time in school, but few are prepared to do anything about it. Laying the foundation before making such a shift is essential to the success of the change. Once a broad-based team has been chosen to do the work, they can follow a process explained in four steps with the apt acronym of T.I.M.E.: Taking stock,…

  1. Incremental Real-Time Bundle Adjustment for Multi-Camera Systems with Points at Infinity

    NASA Astrophysics Data System (ADS)

    Schneider, J.; Läbe, T.; Förstner, W.

    2013-08-01

    This paper presents a concept and first experiments on a keyframe-based incremental bundle adjustment for real-time structure and motion estimation in an unknown scene. In order to avoid periodic batch steps, we use the software iSAM2 for sparse nonlinear incremental optimization, which is highly efficient through incremental variable reordering and fluid relinearization. We adapted the software to allow for (1) multi-view cameras by taking the rigid transformation between the cameras into account, (2) omnidirectional cameras as it can handle arbitrary bundles of rays and (3) scene points at infinity, which improve the estimation of the camera orientation as points at the horizon can be observed over long periods of time. The real-time bundle adjustment refers to sets of keyframes, consisting of frames, one per camera, taken in a synchronized way, that are initiated if a minimal geometric distance to the last keyframe set is exceeded. It uses interest points in the keyframes as observations, which are tracked in the synchronized video streams of the individual cameras and matched across the cameras, if possible. First experiments show the potential of the incremental bundle adjustment w.r.t. time requirements. Our experiments are based on a multi-camera system with four fisheye cameras, which are mounted on a UAV as two stereo pairs, one looking ahead and one looking backwards, providing a large field of view.

  2. Speech perception at positive signal-to-noise ratios using adaptive adjustment of time compression.

    PubMed

    Schlueter, Anne; Brand, Thomas; Lemke, Ulrike; Nitzschner, Stefan; Kollmeier, Birger; Holube, Inga

    2015-11-01

    Positive signal-to-noise ratios (SNRs) characterize listening situations most relevant for hearing-impaired listeners in daily life and should therefore be considered when evaluating hearing aid algorithms. For this, a speech-in-noise test was developed and evaluated, in which the background noise is presented at fixed positive SNRs and the speech rate (i.e., the time compression of the speech material) is adaptively adjusted. In total, 29 younger and 12 older normal-hearing, as well as 24 older hearing-impaired listeners took part in repeated measurements. Younger normal-hearing and older hearing-impaired listeners conducted one of two adaptive methods which differed in adaptive procedure and step size. Analysis of the measurements with regard to list length and estimation strategy for thresholds resulted in a practical method measuring the time compression for 50% recognition. This method uses time-compression adjustment and step sizes according to Versfeld and Dreschler [(2002). J. Acoust. Soc. Am. 111, 401-408], with sentence scoring, lists of 30 sentences, and a maximum likelihood method for threshold estimation. Evaluation of the procedure showed that older participants obtained higher test-retest reliability compared to younger participants. Depending on the group of listeners, one or two lists are required for training prior to data collection.

  3. Multiple time step integrators in ab initio molecular dynamics

    SciTech Connect

    Luehr, Nathan; Martínez, Todd J.; Markland, Thomas E.

    2014-02-28

    Multiple time-scale algorithms exploit the natural separation of time-scales in chemical systems to greatly accelerate the efficiency of molecular dynamics simulations. Although the utility of these methods in systems where the interactions are described by empirical potentials is now well established, their application to ab initio molecular dynamics calculations has been limited by difficulties associated with splitting the ab initio potential into fast and slowly varying components. Here we present two schemes that enable efficient time-scale separation in ab initio calculations: one based on fragment decomposition and the other on range separation of the Coulomb operator in the electronic Hamiltonian. We demonstrate for both water clusters and a solvated hydroxide ion that multiple time-scale molecular dynamics allows for outer time steps of 2.5 fs, which are as large as those obtained when such schemes are applied to empirical potentials, while still allowing for bonds to be broken and reformed throughout the dynamics. This permits computational speedups of up to 4.4x, compared to standard Born-Oppenheimer ab initio molecular dynamics with a 0.5 fs time step, while maintaining the same energy conservation and accuracy.

  4. A shorter time step for eco-friendly reservoir operation does not always produce better water availability and ecosystem benefits

    NASA Astrophysics Data System (ADS)

    Yu, Chunxue; Yin, Xin'an; Yang, Zhifeng; Cai, Yanpeng; Sun, Tao

    2016-09-01

    The time step used in the operation of eco-friendly reservoirs has decreased from monthly to daily, and even sub-daily. The shorter time step is considered a better choice for satisfying downstream environmental requirements because it more closely resembles the natural flow regime. However, little consideration has been given to the influence of different time steps on the ability to simultaneously meet human and environmental flow requirements. To analyze this influence, we used an optimization model to explore the relationships among the time step, environmental flow (e-flow) requirements, and human water needs for a wide range of time steps and e-flow scenarios. We used the degree of hydrologic alteration to evaluate the regime's ability to satisfy the e-flow requirements of riverine ecosystems, and used water supply reliability to evaluate the ability to satisfy human needs. We then applied the model to a case study of China's Tanghe Reservoir. We found four efficient time steps (2, 3, 4, and 5 days), with a remarkably high water supply reliability (around 80%) and a low alteration of the flow regime (<35%). Our analysis of the hydrologic alteration revealed the smallest alteration at time steps ranging from 1 to 7 days. However, longer time steps led to higher water supply reliability to meet human needs under several e-flow scenarios. Our results show that adjusting the time step is a simple way to improve reservoir operation performance to balance human and e-flow needs.

  5. A method for improving time-stepping numerics

    NASA Astrophysics Data System (ADS)

    Williams, P. D.

    2012-04-01

    In contemporary numerical simulations of the atmosphere, evidence suggests that time-stepping errors may be a significant component of total model error, on both weather and climate time-scales. This presentation will review the available evidence, and will then suggest a simple but effective method for substantially improving the time-stepping numerics at no extra computational expense. The most common time-stepping method is the leapfrog scheme combined with the Robert-Asselin (RA) filter. This method is used in the following atmospheric models (and many more): ECHAM, MAECHAM, MM5, CAM, MESO-NH, HIRLAM, KMCM, LIMA, SPEEDY, IGCM, PUMA, COSMO, FSU-GSM, FSU-NRSM, NCEP-GFS, NCEP-RSM, NSEAM, NOGAPS, RAMS, and CCSR/NIES-AGCM. Although the RA filter controls the time-splitting instability in these models, it also introduces non-physical damping and reduces the accuracy. This presentation proposes a simple modification to the RA filter. The modification has become known as the RAW filter (Williams 2011). When used in conjunction with the leapfrog scheme, the RAW filter eliminates the non-physical damping and increases the amplitude accuracy by two orders, yielding third-order accuracy. (The phase accuracy remains second-order.) The RAW filter can easily be incorporated into existing models, typically via the insertion of just a single line of code. Better simulations are obtained at no extra computational expense. Results will be shown from recent implementations of the RAW filter in various atmospheric models, including SPEEDY and COSMO. For example, in SPEEDY, the skill of weather forecasts is found to be significantly improved. In particular, in tropical surface pressure predictions, five-day forecasts made using the RAW filter have approximately the same skill as four-day forecasts made using the RA filter (Amezcua, Kalnay & Williams 2011). These improvements are encouraging for the use of the RAW filter in other models.

  6. Efficient multiple time-stepping algorithms of higher order

    NASA Astrophysics Data System (ADS)

    Demirel, Abdullah; Niegemann, Jens; Busch, Kurt; Hochbruck, Marlis

    2015-03-01

    Multiple time-stepping (MTS) algorithms allow to efficiently integrate large systems of ordinary differential equations, where a few stiff terms restrict the timestep of an otherwise non-stiff system. In this work, we discuss a flexible class of MTS techniques, based on multistep methods. Our approach contains several popular methods as special cases and it allows for the easy construction of novel and efficient higher-order MTS schemes. In addition, we demonstrate how to adapt the stability contour of the non-stiff time-integration to the physical system at hand. This allows significantly larger timesteps when compared to previously known multistep MTS approaches. As an example, we derive novel predictor-corrector (PCMTS) schemes specifically optimized for the time-integration of damped wave equations on locally refined meshes. In a set of numerical experiments, we demonstrate the performance of our scheme on discontinuous Galerkin time-domain (DGTD) simulations of Maxwell's equations.

  7. On the maximum time step in weakly compressible SPH

    NASA Astrophysics Data System (ADS)

    Violeau, Damien; Leroy, Agnès

    2014-01-01

    In the SPH method for viscous fluids, the time step is subject to empirical stability criteria. We proceed to a stability analysis of the Weakly Compressible SPH equations using the von Neumann approach in arbitrary space dimension for unbounded flow. Considering the continuous SPH interpolant based on integrals, we obtain a theoretical stability criterion for the time step, depending on the kernel standard deviation, the speed of sound and the viscosity. The stability domain appears to be almost independent of the kernel choice for a given space discretisation. Numerical tests show that the theory is very accurate, despite the approximations made. We then extend the theory in order to study the influence of the method used to compute the density, of the gradient and divergence SPH operators, of background pressure, of the model used for viscous forces and of a constant velocity gradient. The influence of time integration scheme is also studied, and proved to be prominent. All of the above theoretical developments give excellent agreement against numerical results. It is found that velocity gradients almost do not affect stability, provided some background pressure is used. Finally, the case of bounded flows is briefly addressed from numerical tests in three cases: a laminar Poiseuille flow in a pipe, a lid-driven cavity and the collapse of a water column on a wedge.

  8. A new adaptive time step method for unsteady flow simulations in a human lung.

    PubMed

    Fenández-Tena, Ana; Marcos, Alfonso C; Martínez, Cristina; Keith Walters, D

    2017-04-07

    The innovation presented is a method for adaptive time-stepping that allows clustering of time steps in portions of the cycle for which flow variables are rapidly changing, based on the concept of using a uniform step in a relevant dependent variable rather than a uniform step in the independent variable time. A user-defined function was developed to adapt the magnitude of the time step (adaptive time step) to a defined rate of change in inlet velocity. Quantitative comparison indicates that the new adaptive time stepping method significantly improves accuracy for simulations using an equivalent number of time steps per cycle.

  9. Time-resolved detection probe for homogeneous nucleic acid analyses in one-step format.

    PubMed

    Laitala, Ville; Ylikoski, Alice; Raussi, Hanna-Mari; Ollikka, Pia; Hemmilä, Ilkka

    2007-02-01

    We report here an extension of homogeneous assays based on fluorescence intensity and lifetime measuring on DNA hybridization. A novel decay probe that allows simple one-step nucleic acid detection with subnanomolar sensitivity, and is suitable for closed-tube applications, is introduced. The decay probe uses fluorescence resonance energy transfer (FRET) between a europium chelate donor and an organic fluorophore acceptor. The substantial change in the acceptor emission decay time on hybridization with the target sequence allows the direct separation of the hybridized and unhybridized probe populations in a time-resolved measurement. No additional sample manipulation or self-hybridization of the probes is required. The wavelength and decay time of a decay probe can be adjusted according to the selection of probe length and acceptor fluorophore, thereby making the probes applicable to multiplexed assays. Here we demonstrate the decay probe principle and decay probe-based, one-step, dual DNA assay using celiac disease-related target oligonucleotides (single-nucleotide polymorphisms [SNPs]) as model analytes. Decay probes showed specific response for their complementary DNA target and allowed good signal deconvolution based on simultaneous optical and temporal filtering. This technique potentially could be used to further increase the number of simultaneously detected DNA targets in a simple one-step homogeneous assay.

  10. Multiple-time-stepping generalized hybrid Monte Carlo methods

    SciTech Connect

    Escribano, Bruno; Akhmatskaya, Elena; Reich, Sebastian; Azpiroz, Jon M.

    2015-01-01

    Performance of the generalized shadow hybrid Monte Carlo (GSHMC) method [1], which proved to be superior in sampling efficiency over its predecessors [2–4], molecular dynamics and hybrid Monte Carlo, can be further improved by combining it with multi-time-stepping (MTS) and mollification of slow forces. We demonstrate that the comparatively simple modifications of the method not only lead to better performance of GSHMC itself but also allow for beating the best performed methods, which use the similar force splitting schemes. In addition we show that the same ideas can be successfully applied to the conventional generalized hybrid Monte Carlo method (GHMC). The resulting methods, MTS-GHMC and MTS-GSHMC, provide accurate reproduction of thermodynamic and dynamical properties, exact temperature control during simulation and computational robustness and efficiency. MTS-GHMC uses a generalized momentum update to achieve weak stochastic stabilization to the molecular dynamics (MD) integrator. MTS-GSHMC adds the use of a shadow (modified) Hamiltonian to filter the MD trajectories in the HMC scheme. We introduce a new shadow Hamiltonian formulation adapted to force-splitting methods. The use of such Hamiltonians improves the acceptance rate of trajectories and has a strong impact on the sampling efficiency of the method. Both methods were implemented in the open-source MD package ProtoMol and were tested on a water and a protein systems. Results were compared to those obtained using a Langevin Molly (LM) method [5] on the same systems. The test results demonstrate the superiority of the new methods over LM in terms of stability, accuracy and sampling efficiency. This suggests that putting the MTS approach in the framework of hybrid Monte Carlo and using the natural stochasticity offered by the generalized hybrid Monte Carlo lead to improving stability of MTS and allow for achieving larger step sizes in the simulation of complex systems.

  11. Stepping motor controller

    DOEpatents

    Bourret, Steven C.; Swansen, James E.

    1984-01-01

    A stepping motor is microprocessingly controlled by digital circuitry which monitors the output of a shaft encoder adjustably secured to the stepping motor and generates a subsequent stepping pulse only after the preceding step has occurred and a fixed delay has expired. The fixed delay is variable on a real-time basis to provide for smooth and controlled deceleration.

  12. Stepping motor controller

    DOEpatents

    Bourret, S.C.; Swansen, J.E.

    1982-07-02

    A stepping motor is microprocessor controlled by digital circuitry which monitors the output of a shaft encoder adjustably secured to the stepping motor and generates a subsequent stepping pulse only after the preceding step has occurred and a fixed delay has expired. The fixed delay is variable on a real-time basis to provide for smooth and controlled deceleration.

  13. Daily Time Step Refinement of Optimized Flood Control Rule Curves for a Global Warming Scenario

    NASA Astrophysics Data System (ADS)

    Lee, S.; Fitzgerald, C.; Hamlet, A. F.; Burges, S. J.

    2009-12-01

    Pacific Northwest temperatures have warmed by 0.8 °C since 1920 and are predicted to further increase in the 21st century. Simulated streamflow timing shifts associated with climate change have been found in past research to degrade water resources system performance in the Columbia River Basin when using existing system operating policies. To adapt to these hydrologic changes, optimized flood control operating rule curves were developed in a previous study using a hybrid optimization-simulation approach which rebalanced flood control and reservoir refill at a monthly time step. For the climate change scenario, use of the optimized flood control curves restored reservoir refill capability without increasing flood risk. Here we extend the earlier studies using a detailed daily time step simulation model applied over a somewhat smaller portion of the domain (encompassing Libby, Duncan, and Corra Linn dams, and Kootenai Lake) to evaluate and refine the optimized flood control curves derived from monthly time step analysis. Moving from a monthly to daily analysis, we found that the timing of flood control evacuation needed adjustment to avoid unintended outcomes affecting Kootenai Lake. We refined the flood rule curves derived from monthly analysis by creating a more gradual evacuation schedule, but kept the timing and magnitude of maximum evacuation the same as in the monthly analysis. After these refinements, the performance at monthly time scales reported in our previous study proved robust at daily time scales. Due to a decrease in July storage deficits, additional benefits such as more revenue from hydropower generation and more July and August outflow for fish augmentation were observed when the optimized flood control curves were used for the climate change scenario.

  14. Thermodynamics and kinetics of large-time-step molecular dynamics.

    PubMed

    Rao, Francesco; Spichty, Martin

    2012-02-15

    Molecular dynamics (MD) simulations provide essential information about the thermodynamics and kinetics of proteins. Technological advances in both hardware and algorithms have seen this method accessing timescales that used to be unreachable only few years ago. The quest to simulate slow, biologically relevant macromolecular conformational changes, is still open. Here, we present an approximate approach to increase the speed of MD simulations by a factor of ∼4.5. This is achieved by using a large integration time step of 7 fs, in combination with frozen covalent bonds and look-up tables for nonbonded interactions of the solvent. Extensive atomistic MD simulations for a flexible peptide in water show that the approach reproduces the peptide's equilibrium conformational changes, preserving the essential properties of both thermodynamics and kinetics. Comparison of this approximate method with state-of-the-art implicit solvation simulations indicates that the former provides a better description of the underlying free-energy surface. Finally, simulations of a 33-residue peptide show that these fast MD settings are readily applicable to investigate biologically relevant systems.

  15. Effects of Timing of Adversity on Adolescent and Young Adult Adjustment.

    PubMed

    Kiff, Cara J; Cortes, Rebecca; Lengua, Lilana; Kosterman, Rick; Hawkins, J David; Mason, W Alex

    2012-06-01

    Effects of Timing of Adversity on Adolescent and Young Adult Adjustment Abstract Exposure to adversity during childhood and adolescence predicts adjustment across development. Further, adolescent adjustment problems persist into young adulthood. This study examined relations of contextual adversity with concurrent adolescent adjustment and prospective mental health and health outcomes in young adulthood. A longitudinal sample (N = 808) was followed from age 10 through 27. Perceptions of neighborhood in childhood predicted depression, alcohol use disorders, and HIV risk in young adulthood. Further, the timing of adversity was important in determining the type of problem experienced in adulthood. Youth adjustment predicted adult outcomes, and in some cases, mediated the relation between adversity and outcomes. These findings support the importance of adversity in predicting adjustment and elucidate factors that affect outcomes into young adulthood.

  16. Coherent Risk-Adjusted Decisions Over Time: a Bilevel Programming Approach

    DTIC Science & Technology

    2015-03-23

    AFRL-AFOSR-VA-TR-2015-0310 Coherent Risk -Adjusted Decisions Over Time: a Bilevel Programming Approach Jonathan Eckstein RUTGERS THE STATE UNIVERSITY...14/2015 4. TITLE AND SUBTITLE Final Project Report: Coherent Risk -Adjusted Decisions over Time: a Bilevel Programming Approach 5a. CONTRACT NUMBER...tested two techniques for approximating a time-inconsistent risk -averse objective function with a time-consistent one. We also investigated rolling

  17. The IERS and Adjustments to Coordinated Universal Time

    DTIC Science & Technology

    2014-01-01

    is formulated by the Bureau International des Poids et Mesures (BIPM) using time comparisons obtained from atomic clocks and is the standard for...5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...U.S. Naval Observatory, ,Washington,,DC, 20392 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES

  18. Analysis of one-step and two-step real-time RT-PCR using SuperScript III.

    PubMed

    Wacker, Michael J; Godard, Michael P

    2005-09-01

    Real-time reverse transcription polymerase chain reaction (RT-PCR) is a commonly used technique to analyze gene expression. There has been little research conducted to test if SuperScript III quantitative one-step (reverse transcription carried out in the same tube as PCR) and two-step (reverse transcription carried out in a separate reaction) RT-PCR systems provide similar real-time results. In this study, real-time reactions were set up using the housekeeping genes glyceraldehyde phosphate dehydrogenase (GAPDH), beta2-microglobulin (B2M), and RNA polymerase 2 subunit A (PolR2A). Reaction efficiencies were determined by generating standard curves using total RNA isolated from human skeletal muscle and brain. Reaction efficiencies ranged from 97.7+/-0.9% to 99.4+/-1.8% for one-step and 98.0+/-0.2% to 102.6+/-1.3% for two-step RT-PCR (R2 values for all reactions>or=0.995). The sensitivities of one-step and two-step methods, as measured by cycle threshold values, were similar for GAPDH and B2M. However, for the lesser expressed PolR2A mRNA there was a 5 cycle lower threshold for one-step. In summary, both SuperScript III one-step and two-step methods yield reaction efficiencies close to 100% and produce similar, accurate, linear standard curves. However, using the one-step method with gene-specific priming may be more sensitive for quantification of certain genes such as PolR2A.

  19. Effects of the computational time step on numerical solutions for turbulent flow

    NASA Technical Reports Server (NTRS)

    Choi, Haecheon; Moin, Parviz

    1994-01-01

    Effects of large computational time steps on the computed turbulence were investigated using a fully implicit method. In turbulent channel flow computations the largest computational time step in wall units which led to accurate prediction of turbulence statistics was determined. Turbulence fluctuations could not be sustained if the computational time step was near or larger than the Kolmogorov time scale.

  20. Lean Software Development: One Step at a Time

    DTIC Science & Technology

    2010-04-01

    NVAN Types of Waste L SW A first step in implementing Lean software development is learning to Lean Manufacturing ean Development Defects Defects...move on… COPYRIGHT © 2008 THE BOEING COMPANY Principle 2: Build Quality In Key insight from Lean manufacturing : • You cannot inspect quality into a

  1. Automatic multirate methods for ordinary differential equations. [Adaptive time steps

    SciTech Connect

    Gear, C.W.

    1980-01-01

    A study is made of the application of integration methods in which different step sizes are used for different members of a system of equations. Such methods can result in savings if the cost of derivative evaluation is high or if a system is sparse; however, the estimation and control of errors is very difficult and can lead to high overheads. Three approaches are discussed, and it is shown that the least intuitive is the most promising. 2 figures.

  2. The prevalence of upright non-stepping time in comparison to stepping time in 11-13 year old school children across seasons.

    PubMed

    McCrorie, P Rw; Duncan, E; Granat, M H; Stansfield, B W

    2012-11-01

    Evidence suggests that behaviours such as standing are beneficial for our health. Unfortunately, little is known of the prevalence of this state, its importance in relation to time spent stepping or variation across seasons. The aim of this study was to quantify, in young adolescents, the prevalence and seasonal changes in time spent upright and not stepping (UNSt(time)) as well as time spent upright and stepping (USt(time)), and their contribution to overall upright time (U(time)). Thirty-three adolescents (12.2 ± 0.3 y) wore the activPAL activity monitor during four school days on two occasions: November/December (winter) and May/June (summer). UNSt(time) contributed 60% of daily U(time) at winter (Mean = 196 min) and 53% at summer (Mean = 171 min); a significant seasonal effect, p < 0.001. USt(time) was significantly greater in summer compared to winter (153 min versus 131 min, p < 0.001). The effects in UNSt(time) could be explained through significant seasonal differences during the school hours (09:00-16:00), whereas the effects in USt(time) could be explained through significant seasonal differences in the evening period (16:00-22:00). Adolescents spent a greater amount of time upright and not stepping than they did stepping, in both winter and summer. The observed seasonal effects for both UNSt(time) and USt(time) provide important information for behaviour change intervention programs.

  3. Error and timing analysis of multiple time-step integration methods for molecular dynamics

    NASA Astrophysics Data System (ADS)

    Han, Guowen; Deng, Yuefan; Glimm, James; Martyna, Glenn

    2007-02-01

    Molecular dynamics simulations of biomolecules performed using multiple time-step integration methods are hampered by resonance instabilities. We analyze the properties of a simple 1D linear system integrated with the symplectic reference system propagator MTS (r-RESPA) technique following earlier work by others. A closed form expression for the time step dependent Hamiltonian which corresponds to r-RESPA integration of the model is derived. This permits us to present an analytic formula for the dependence of the integration accuracy on short-range force cutoff range. A detailed analysis of the force decomposition for the standard Ewald summation method is then given as the Ewald method is a good candidate to achieve high scaling on modern massively parallel machines. We test the new analysis on a realistic system, a protein in water. Under Langevin dynamics with a weak friction coefficient ( ζ=1 ps) to maintain temperature control and using the SHAKE algorithm to freeze out high frequency vibrations, we show that the 5 fs resonance barrier present when all degrees of freedom are unconstrained is postponed to ≈12 fs. An iso-error boundary with respect to the short-range cutoff range and multiple time step size agrees well with the analytical results which are valid due to dominance of the high frequency modes in determining integrator accuracy. Using r-RESPA to treat the long range interactions results in a 6× increase in efficiency for the decomposition described in the text.

  4. Its Time to Step into Science at Medgar Evers College.

    PubMed

    Carroll, Margaret A; Skeete, Dereck; Catapane, Edward J

    2008-01-01

    Over the next decade, demand and job opportunities in science and engineering (S&E) are expected to grow. With so many S&E "baby-boomers" retiring, questions arise as to whether America will be able to attract enough young people into Science, Technology, Engineering and Mathematics (STEM) to maintain a S&E workforce that keeps up with what is becoming a more globally technologically and scientifically advancing society. Furthermore, considering recent projections of a nation more racially and ethnically diverse by mid-century, will America's future STEM workforce reflect the diversity projected for our growing U.S. population? In 2006, the authors received an award from the National Science Foundation (NSF) to direct a new initiative titled "STEP into Science." Funded under the Science, Technology, Engineering and Mathematics Talent Expansion Program (STEP) of the NSF Division of Undergraduate Education, the main goal of the project is to increase the number of STEM majors that graduate with baccalaureate degree, specifically B.S. degrees in Biology or Environmental Science. The program has had great success implementing the use of "peer recruiters" to attract more high school, transfer, and non-science college students into STEM majors and places emphasis on the role of undergraduate research experiences as a successful strategy to increase the quality and retention of science majors through their baccalaureate degree. Since the inception of the program, total STEM enrollment has more than doubled and the number of majors actively engaged in research has risen 38% with a concurrent increase in student research presentations at scientific conference, and the number of students receiving external research internships and travel awards to attend national conferences. The number of STEM graduates (both A.S. and B.S.) has also increased and the program anticipates that these and future STEP into Science graduates will continue on to Masters and Doctoral programs in

  5. A Step-by-Step Picture of Pulsed (Time-Domain) NMR.

    ERIC Educational Resources Information Center

    Schwartz, Leslie J.

    1988-01-01

    Discusses a method for teaching time pulsed NMR principals that are as simple and pictorial as possible. Uses xyz coordinate figures and presents theoretical explanations using a Fourier transformation spectrum. Assumes no previous knowledge of quantum mechanics for students. Usable for undergraduates. (MVL)

  6. Lateral root initiation: one step at a time.

    PubMed

    De Smet, Ive

    2012-03-01

    Plant growth relies heavily on a root system that is hidden belowground, which develops post-embryonically through the formation of lateral roots. The de novo formation of lateral root organs requires tightly coordinated asymmetric cell division of a limited number of pericycle cells located at the xylem pole. This typically involves the formation of founder cells, followed by a number of cellular changes until the cells divide and give rise to two unequally sized daughter cells. Over the past few years, our knowledge of the regulatory mechanisms behind lateral root initiation has increased dramatically. Here, I will summarize these recent advances, focusing on the prominent role of auxin and cell cycle activity, and elaborating on the three key steps of pericycle cell priming, founder cell establishment and asymmetric cell division. Taken together, recent findings suggest a tentative model in which successive auxin response modules are crucial for lateral root initiation, and additional factors provide more layers of control.

  7. Estimating Child Sleep From Parent Report of Time in Bed: Development and Evaluation of Adjustment Approaches

    PubMed Central

    Lundahl, Alyssa; Molfese, Dennis L.; Waford, Rachel N.; Roman, Adrienne; Gozal, David; Molfese, Victoria J.; Ferguson, Melissa C.

    2014-01-01

    Objective To develop and evaluate adjustment factors to convert parent-reported time in bed to an estimate of child sleep time consistent with objective measurement. Methods A community sample of 217 children aged 4–9 years (mean age = 6.6 years) wore actigraph wristwatches to objectively measure sleep for 7 days while parents completed reports of child sleep each night. After examining the moderators of the discrepancy between parent reports and actigraphy, 3 adjustment factors were evaluated. Results Parent report of child sleep overestimated nightly sleep duration by ∼24 min per night relative to actigraphy. Child age, gender, and sleep quality all had small or nonsignificant associations with correspondence between parent report and actigraph. Empirically derived adjustment factors significantly reduced the discrepancy between parent report and objective measurement. Conclusions Simple adjustment factors can enhance the correspondence and utility of parent reports of child sleep duration for clinical and research purposes. PMID:24781412

  8. Association Between Sitting Time and Cardiometabolic Risk Factors After Adjustment for Cardiorespiratory Fitness, Cooper Center Longitudinal Study, 2010–2013

    PubMed Central

    Shuval, Kerem; Balasubramanian, Bijal A.; Kendzor, Darla E.; Radford, Nina B.; DeFina, Laura F.; Gabriel, Kelley Pettee

    2016-01-01

    Introduction Objective estimates, based on waist-worn accelerometers, indicate that adults spend over half their day (55%) in sedentary behaviors. Our study examined the association between sitting time and cardiometabolic risk factors after adjustment for cardiorespiratory fitness (CRF). Methods A cross-sectional analysis was conducted with 4,486 men and 1,845 women who reported daily estimated sitting time, had measures for adiposity, blood lipids, glucose, and blood pressure, and underwent maximal stress testing. We used a modeling strategy using logistic regression analysis to assess CRF as a potential effect modifier and to control for potential confounding effects of CRF. Results Men who sat almost all of the time (about 100%) were more likely to be obese whether defined by waist girth (OR, 2.61; 95% CI, 1.25–5.47) or percentage of body fat (OR, 3.33; 95% CI, 1.35–8.20) than were men who sat almost none of the time (about 0%). Sitting time was not significantly associated with other cardiometabolic risk factors after adjustment for CRF level. For women, no significant associations between sitting time and cardiometabolic risk factors were observed after adjustment for CRF and other covariates. Conclusion As health professionals struggle to find ways to combat obesity and its health effects, reducing sitting time can be an initial step in a total physical activity plan that includes strategies to reduce sedentary time through increases in physical activity among men. In addition, further research is needed to elucidate the relationships between sitting time and CRF for women as well as the underlying mechanisms involved in these relationships. PMID:28033088

  9. Finite element/finite volume approaches with adaptive time stepping strategies for transient thermal problems

    NASA Technical Reports Server (NTRS)

    Mohan, Ram V.; Tamma, Kumar K.

    1993-01-01

    An adaptive time stepping strategy for transient thermal analysis of engineering systems is described which computes the time step based on the local truncation error with a good global error control and obtains optimal time steps to be used during the analysis. Combined mesh partitionings involving FEM/FVM meshes based on physical situations to obtain numerically improved physical representations are also proposed. Numerical test cases are described and comparative pros and cons are identified for practical situations.

  10. Time-step limits for a Monte Carlo Compton-scattering method

    SciTech Connect

    Densmore, Jeffery D; Warsa, James S; Lowrie, Robert B

    2009-01-01

    We perform a stability analysis of a Monte Carlo method for simulating the Compton scattering of photons by free electron in high energy density applications and develop time-step limits that avoid unstable and oscillatory solutions. Implementing this Monte Carlo technique in multi physics problems typically requires evaluating the material temperature at its beginning-of-time-step value, which can lead to this undesirable behavior. With a set of numerical examples, we demonstrate the efficacy of our time-step limits.

  11. Formulation of an explicit-multiple-time-step time integration method for use in a global primitive equation grid model

    NASA Technical Reports Server (NTRS)

    Chao, W. C.

    1982-01-01

    With appropriate modifications, a recently proposed explicit-multiple-time-step scheme (EMTSS) is incorporated into the UCLA model. In this scheme, the linearized terms in the governing equations that generate the gravity waves are split into different vertical modes. Each mode is integrated with an optimal time step, and at periodic intervals these modes are recombined. The other terms are integrated with a time step dictated by the CFL condition for low-frequency waves. This large time step requires a special modification of the advective terms in the polar region to maintain stability. Test runs for 72 h show that EMTSS is a stable, efficient and accurate scheme.

  12. IMPROVEMENTS TO THE TIME STEPPING ALGORITHM OF RELAP5-3D

    SciTech Connect

    Cumberland, R.; Mesina, G.

    2009-01-01

    The RELAP5-3D time step method is used to perform thermo-hydraulic and neutronic simulations of nuclear reactors and other devices. It discretizes time and space by numerically solving several differential equations. Previously, time step size was controlled by halving or doubling the size of a previous time step. This process caused the code to run slower than it potentially could. In this research project, the RELAP5-3D time step method was modifi ed to allow a new method of changing time steps to improve execution speed and to control error. The new RELAP5-3D time step method being studied involves making the time step proportional to the material courant limit (MCL), while insuring that the time step does not increase by more than a factor of two between advancements. As before, if a step fails or mass error is excessive, the time step is cut in half. To examine performance of the new method, a measure of run time and a measure of error were plotted against a changing MCL proportionality constant (m) in seven test cases. The removal of the upper time step limit produced a small increase in error, but a large decrease in execution time. The best value of m was found to be 0.9. The new algorithm is capable of producing a signifi cant increase in execution speed, with a relatively small increase in mass error. The improvements made are now under consideration for inclusion as a special option in the RELAP5-3D production code.

  13. Convergence Acceleration for Multistage Time-Stepping Schemes

    NASA Technical Reports Server (NTRS)

    Swanson, R. C.; Turkel, Eli L.; Rossow, C-C; Vasta, V. N.

    2006-01-01

    The convergence of a Runge-Kutta (RK) scheme with multigrid is accelerated by preconditioning with a fully implicit operator. With the extended stability of the Runge-Kutta scheme, CFL numbers as high as 1000 could be used. The implicit preconditioner addresses the stiffness in the discrete equations associated with stretched meshes. Numerical dissipation operators (based on the Roe scheme, a matrix formulation, and the CUSP scheme) as well as the number of RK stages are considered in evaluating the RK/implicit scheme. Both the numerical and computational efficiency of the scheme with the different dissipation operators are discussed. The RK/implicit scheme is used to solve the two-dimensional (2-D) and three-dimensional (3-D) compressible, Reynolds-averaged Navier-Stokes equations. In two dimensions, turbulent flows over an airfoil at subsonic and transonic conditions are computed. The effects of mesh cell aspect ratio on convergence are investigated for Reynolds numbers between 5.7 x 10(exp 6) and 100.0 x 10(exp 6). Results are also obtained for a transonic wing flow. For both 2-D and 3-D problems, the computational time of a well-tuned standard RK scheme is reduced at least a factor of four.

  14. Operational flood control of a low-lying delta system using large time step Model Predictive Control

    NASA Astrophysics Data System (ADS)

    Tian, Xin; van Overloop, Peter-Jules; Negenborn, Rudy R.; van de Giesen, Nick

    2015-01-01

    The safety of low-lying deltas is threatened not only by riverine flooding but by storm-induced coastal flooding as well. For the purpose of flood control, these deltas are mostly protected in a man-made environment, where dikes, dams and other adjustable infrastructures, such as gates, barriers and pumps are widely constructed. Instead of always reinforcing and heightening these structures, it is worth considering making the most of the existing infrastructure to reduce the damage and manage the delta in an operational and overall way. In this study, an advanced real-time control approach, Model Predictive Control, is proposed to operate these structures in the Dutch delta system (the Rhine-Meuse delta). The application covers non-linearity in the dynamic behavior of the water system and the structures. To deal with the non-linearity, a linearization scheme is applied which directly uses the gate height instead of the structure flow as the control variable. Given the fact that MPC needs to compute control actions in real-time, we address issues regarding computational time. A new large time step scheme is proposed in order to save computation time, in which different control variables can have different control time steps. Simulation experiments demonstrate that Model Predictive Control with the large time step setting is able to control a delta system better and much more efficiently than the conventional operational schemes.

  15. Family and Center Contributions to the Adjustment of Infants in Full-Time Day Care.

    ERIC Educational Resources Information Center

    Ainslie, Ricardo C.

    1990-01-01

    Two studies examine moderators of adjustment in children who have been in full-time day care since infancy. Results suggest that, for children in child care of reasonably good quality, home variables may be more important than center variables in moderating security of attachment. (BB)

  16. Shyness-Sensitivity, Aggression, and Adjustment in Urban Chinese Adolescents at Different Historical Times

    ERIC Educational Resources Information Center

    Liu, Junsheng; Chen, Xinyin; Li, Dan; French, Doran

    2012-01-01

    The market-oriented economic reform in China over the past two decades has resulted in considerable changes in social attitudes regarding youth's behaviors. This study examined the relations of shyness and aggression to adjustment in Chinese adolescents at different historical times. Participants came from two cohorts (1994 and 2008) of…

  17. Adjustment of sleep and the circadian temperature rhythm after flights across nine time zones

    NASA Technical Reports Server (NTRS)

    Gander, Philippa H.; Myhre, Grete; Graeber, R. Curtis; Lauber, John K.; Andersen, Harald T.

    1989-01-01

    The adjustment of sleep-wake patterns and the circadian temperature rhythm was monitored in nine Royal Norwegian Airforce volunteers operating P-3 aircraft during a westward training deployment across nine time zones. Subjects recorded all sleep and nap times, rated nightly sleep quality, and completed personality inventories. Rectal temperature, heart rate, and wrist activity were continuously monitored. Adjustment was slower after the return eastward flight than after the outbound westward flight. The eastward flight produced slower readjustment of sleep timing to local time and greater interindividual variability in the patterns of adjustment of sleep and temperature. One subject apparently exhibited resynchronization by partition, with the temperature rhythm undergoing the reciprocal 15-h delay. In contrast, average heart rates during sleep were significantly elevated only after westward flight. Interindividual differences in adjustment of the temperature rhythm were correlated with some of the personality measures. Larger phase delays in the overall temperature waveform (as measured on the 5th day after westward flight) were exhibited by extraverts, and less consistently by evening types.

  18. Comparing an annual and daily time-step model for predicting field-scale phosphorus loss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous models exist for describing phosphorus (P) losses from agricultural fields. The complexity of these models varies considerably ranging from simple empirically-based annual time-step models to more complex process-based daily time step models. While better accuracy is often assumed with more...

  19. Controlling Discrete Time T-S Fuzzy Chaotic Systems via Adaptive Adjustment

    NASA Astrophysics Data System (ADS)

    Nian, Yibei; Zheng, Yongai

    In order to overcome typical drawbacks of the OGY control, i.e. the long waiting time for control to be applied and the accessible turning system parameter in advance, this paper presents a new chaos control method based on Takagi- Sugeno (T-S) fuzzy model and adaptive adjustment. This method represents a chaotic system by linear models in different state space regions based on T-S fuzzy model and then stabilize the linear models in different state space regions by the adaptive adjustment mechanism. An example for the Henon map is given to demonstrate the effectiveness of the proposed method.

  20. How to Keep a Spring in Your Step with Daylight Saving Time

    MedlinePlus

    ... a Spring in Your Step With Daylight Saving Time Expert advice on ways to weather the lost ... Clocks will spring ahead one hour with the time change on Sunday morning, but medical experts have ...

  1. An adaptive time-stepping strategy for solving the phase field crystal model

    SciTech Connect

    Zhang, Zhengru; Ma, Yuan; Qiao, Zhonghua

    2013-09-15

    In this work, we will propose an adaptive time step method for simulating the dynamics of the phase field crystal (PFC) model. The numerical simulation of the PFC model needs long time to reach steady state, and then large time-stepping method is necessary. Unconditionally energy stable schemes are used to solve the PFC model. The time steps are adaptively determined based on the time derivative of the corresponding energy. It is found that the use of the proposed time step adaptivity cannot only resolve the steady state solution, but also the dynamical development of the solution efficiently and accurately. The numerical experiments demonstrate that the CPU time is significantly saved for long time simulations.

  2. Using a detailed uncertainty analysis to adjust mapped rates of forest disturbance derived from Landsat time series data (Invited)

    NASA Astrophysics Data System (ADS)

    Cohen, W. B.; Yang, Z.; Stehman, S.; Huang, C.; Healey, S. P.

    2013-12-01

    Forest ecosystem process models require spatially and temporally detailed disturbance data to accurately predict fluxes of carbon or changes in biodiversity over time. A variety of new mapping algorithms using dense Landsat time series show great promise for providing disturbance characterizations at an annual time step. These algorithms provide unprecedented detail with respect to timing, magnitude, and duration of individual disturbance events, and causal agent. But all maps have error and disturbance maps in particular can have significant omission error because many disturbances are relatively subtle. Because disturbance, although ubiquitous, can be a relatively rare event spatially in any given year, omission errors can have a great impact on mapped rates. Using a high quality reference disturbance dataset, it is possible to not only characterize map errors but also to adjust mapped disturbance rates to provide unbiased rate estimates with confidence intervals. We present results from a national-level disturbance mapping project (the North American Forest Dynamics project) based on the Vegetation Change Tracker (VCT) with annual Landsat time series and uncertainty analyses that consist of three basic components: response design, statistical design, and analyses. The response design describes the reference data collection, in terms of the tool used (TimeSync), a formal description of interpretations, and the approach for data collection. The statistical design defines the selection of plot samples to be interpreted, whether stratification is used, and the sample size. Analyses involve derivation of standard agreement matrices between the map and the reference data, and use of inclusion probabilities and post-stratification to adjust mapped disturbance rates. Because for NAFD we use annual time series, both mapped and adjusted rates are provided at an annual time step from ~1985-present. Preliminary evaluations indicate that VCT captures most of the higher

  3. Effect of time-activity adjustment on exposure assessment for traffic-related ultrafine particles.

    PubMed

    Lane, Kevin J; Levy, Jonathan I; Scammell, Madeleine Kangsen; Patton, Allison P; Durant, John L; Mwamburi, Mkaya; Zamore, Wig; Brugge, Doug

    2015-01-01

    Exposures to ultrafine particles (<100 nm, estimated as particle number concentration, PNC) differ from ambient concentrations because of the spatial and temporal variability of both PNC and people. Our goal was to evaluate the influence of time-activity adjustment on exposure assignment and associations with blood biomarkers for a near-highway population. A regression model based on mobile monitoring and spatial and temporal variables was used to generate hourly ambient residential PNC for a full year for a subset of participants (n=140) in the Community Assessment of Freeway Exposure and Health study. We modified the ambient estimates for each hour using personal estimates of hourly time spent in five micro-environments (inside home, outside home, at work, commuting, other) as well as particle infiltration. Time-activity adjusted (TAA)-PNC values differed from residential ambient annual average (RAA)-PNC, with lower exposures predicted for participants who spent more time away from home. Employment status and distance to highway had a differential effect on TAA-PNC. We found associations of RAA-PNC with high sensitivity C-reactive protein and Interleukin-6, although exposure-response functions were non-monotonic. TAA-PNC associations had larger effect estimates and linear exposure-response functions. Our findings suggest that time-activity adjustment improves exposure assessment for air pollutants that vary greatly in space and time.

  4. Effect of time-activity adjustment on exposure assessment for traffic-related ultrafine particles

    PubMed Central

    Lane, Kevin J; Levy, Jonathan I; Scammell, Madeleine Kangsen; Patton, Allison P; Durant, John L; Mwamburi, Mkaya; Zamore, Wig; Brugge, Doug

    2015-01-01

    Exposures to ultrafine particles (<100 nm, estimated as particle number concentration, PNC) differ from ambient concentrations because of the spatial and temporal variability of both PNC and people. Our goal was to evaluate the influence of time-activity adjustment on exposure assignment and associations with blood biomarkers for a near-highway population. A regression model based on mobile monitoring and spatial and temporal variables was used to generate hourly ambient residential PNC for a full year for a subset of participants (n=140) in the Community Assessment of Freeway Exposure and Health study. We modified the ambient estimates for each hour using personal estimates of hourly time spent in five micro-environments (inside home, outside home, at work, commuting, other) as well as particle infiltration. Time-activity adjusted (TAA)-PNC values differed from residential ambient annual average (RAA)-PNC, with lower exposures predicted for participants who spent more time away from home. Employment status and distance to highway had a differential effect on TAA-PNC. We found associations of RAA-PNC with high sensitivity C-reactive protein and Interleukin-6, although exposure-response functions were non-monotonic. TAA-PNC associations had larger effect estimates and linear exposure-response functions. Our findings suggest that time-activity adjustment improves exposure assessment for air pollutants that vary greatly in space and time. PMID:25827314

  5. Sensitivity of a thermodynamic sea ice model with leads to time step size

    NASA Technical Reports Server (NTRS)

    Ledley, T. S.

    1985-01-01

    The characteristics of sea ice models, developed to study the physics of the growth and melt of ice at the ocean surface and the variations in ice extent, depend on the size of the time step. Thus, to study longer-term variations within a reasonable computer budget, a model with a scheme allowing longer time steps has been constructed. However, the results produced by the model can definitely depend on the length of the time step. The sensitivity of a model to time-step size can be reduced by appropriate approaches. The present investigation is concerned with experiments which use a formulation of a lead parameterization that can be considered as a first step toward the development of a lead parameterization suitable for a use in long-term climate studies.

  6. Multirate time-stepping least squares shadowing method for unsteady turbulent flow

    NASA Astrophysics Data System (ADS)

    Bae, Hyunji Jane; Moin, Parviz

    2014-11-01

    The recently developed least squares shadowing (LSS) method reformulates unsteady turbulent flow simulations to be well-conditioned time domain boundary value problems. The reformulation can enable scalable parallel-in-time simulation of turbulent flows (Wang et al. Phys. Fluid [2013]). A LSS method with multirate time-stepping was implemented to avoid the necessity of taking small global time-steps (restricted by the largest value of the Courant number on the grid) and therefore result in a more efficient algorithm. We will present the results of the multirate time-stepping LSS compared to a single rate time-stepping LSS and discuss the computational savings. Hyunji Jane Bae acknowledges support from the Stanford Graduate Fellowship.

  7. GOTHIC: Gravitational oct-tree code accelerated by hierarchical time step controlling

    NASA Astrophysics Data System (ADS)

    Miki, Yohei; Umemura, Masayuki

    2017-04-01

    The tree method is a widely implemented algorithm for collisionless N-body simulations in astrophysics well suited for GPU(s). Adopting hierarchical time stepping can accelerate N-body simulations; however, it is infrequently implemented and its potential remains untested in GPU implementations. We have developed a Gravitational Oct-Tree code accelerated by HIerarchical time step Controlling named GOTHIC, which adopts both the tree method and the hierarchical time step. The code adopts some adaptive optimizations by monitoring the execution time of each function on-the-fly and minimizes the time-to-solution by balancing the measured time of multiple functions. Results of performance measurements with realistic particle distribution performed on NVIDIA Tesla M2090, K20X, and GeForce GTX TITAN X, which are representative GPUs of the Fermi, Kepler, and Maxwell generation of GPUs, show that the hierarchical time step achieves a speedup by a factor of around 3-5 times compared to the shared time step. The measured elapsed time per step of GOTHIC is 0.30 s or 0.44 s on GTX TITAN X when the particle distribution represents the Andromeda galaxy or the NFW sphere, respectively, with 224 = 16,777,216 particles. The averaged performance of the code corresponds to 10-30% of the theoretical single precision peak performance of the GPU.

  8. Consistency of internal fluxes in a hydrological model running at multiple time steps

    NASA Astrophysics Data System (ADS)

    Ficchi, Andrea; Perrin, Charles; Andréassian, Vazken

    2016-04-01

    Improving hydrological models remains a difficult task and many ways can be explored, among which one can find the improvement of spatial representation, the search for more robust parametrization, the better formulation of some processes or the modification of model structures by trial-and-error procedure. Several past works indicate that model parameters and structure can be dependent on the modelling time step, and there is thus some rationale in investigating how a model behaves across various modelling time steps, to find solutions for improvements. Here we analyse the impact of data time step on the consistency of the internal fluxes of a rainfall-runoff model run at various time steps, by using a large data set of 240 catchments. To this end, fine time step hydro-climatic information at sub-hourly resolution is used as input of a parsimonious rainfall-runoff model (GR) that is run at eight different model time steps (from 6 minutes to one day). The initial structure of the tested model (i.e. the baseline) corresponds to the daily model GR4J (Perrin et al., 2003), adapted to be run at variable sub-daily time steps. The modelled fluxes considered are interception, actual evapotranspiration and intercatchment groundwater flows. Observations of these fluxes are not available, but the comparison of modelled fluxes at multiple time steps gives additional information for model identification. The joint analysis of flow simulation performance and consistency of internal fluxes at different time steps provides guidance to the identification of the model components that should be improved. Our analysis indicates that the baseline model structure is to be modified at sub-daily time steps to warrant the consistency and realism of the modelled fluxes. For the baseline model improvement, particular attention is devoted to the interception model component, whose output flux showed the strongest sensitivity to modelling time step. The dependency of the optimal model

  9. Automatic Time Stepping with Global Error Control for Groundwater Flow Models

    SciTech Connect

    Tang, Guoping

    2008-09-01

    An automatic time stepping with global error control is proposed for the time integration of the diffusion equation to simulate groundwater flow in confined aquifers. The scheme is based on an a posteriori error estimate for the discontinuous Galerkin (dG) finite element methods. A stability factor is involved in the error estimate and it is used to adapt the time step and control the global temporal error for the backward difference method. The stability factor can be estimated by solving a dual problem. The stability factor is not sensitive to the accuracy of the dual solution and the overhead computational cost can be minimized by solving the dual problem using large time steps. Numerical experiments are conducted to show the application and the performance of the automatic time stepping scheme. Implementation of the scheme can lead to improvement in accuracy and efficiency for groundwater flow models.

  10. Time warp edit distance with stiffness adjustment for time series matching.

    PubMed

    Marteau, Pierre-François

    2009-02-01

    In a way similar to the string-to-string correction problem, we address discrete time series similarity in light of a time-series-to-time-series-correction problem for which the similarity between two time series is measured as the minimum cost sequence of edit operations needed to transform one time series into another. To define the edit operations, we use the paradigm of a graphical editing process and end up with a dynamic programming algorithm that we call Time Warp Edit Distance (TWED). TWED is slightly different in form from Dynamic Time Warping (DTW), Longest Common Subsequence (LCSS), or Edit Distance with Real Penalty (ERP) algorithms. In particular, it highlights a parameter that controls a kind of stiffness of the elastic measure along the time axis. We show that the similarity provided by TWED is a potentially useful metric in time series retrieval applications since it could benefit from the triangular inequality property to speed up the retrieval process while tuning the parameters of the elastic measure. In that context, a lower bound is derived to link the matching of time series into downsampled representation spaces to the matching into the original space. The empiric quality of the TWED distance is evaluated on a simple classification task. Compared to Edit Distance, DTW, LCSS, and ERP, TWED has proved to be quite effective on the considered experimental task.

  11. Valve timing adjusting mechanism for internal combustion engine for adjusting timing of intake valve and/or exhaust valve corresponding to engine operating conditions

    SciTech Connect

    Akassaka, A.; Suga, S.; Sawada, T.

    1989-03-14

    A valve timing adjusting mechanism for an internal combustion engine is described, comprising: a camshaft carrying a cam for driving one of an intake valve and an exhaust valve, the camshaft having a section formed with first helical gear teeth; a cam pulley engaging a timing belt driven by the engine for rotation in synchronism with engine revolution, the cam pulley having second helical gear teeth; a ring gear having inner and outer helical gear teeth engageable with the first and second gear teeth of the camshaft and the cam pulley; first means for defining an enclosed chamber facing one planar face of the ring gear and connected with a fluid pressure source to receive pressurized fluid therefrom; a spring means associated with the other planar face of the ring gear for exerting an initial biasing force on the ring gear in opposition to the force due to the pressure on the ring gear from the enclosed chamber; and second means for controlling the fluid pressure introduced into the enclosed chamber in accordance with engine operating conditions so as to shift the ring gear between two positions.

  12. An Adaptive Fourier Filter for Relaxing Time Stepping Constraints for Explicit Solvers

    SciTech Connect

    Gelb, Anne; Archibald, Richard K

    2015-01-01

    Filtering is necessary to stabilize piecewise smooth solutions. The resulting diffusion stabilizes the method, but may fail to resolve the solution near discontinuities. Moreover, high order filtering still requires cost prohibitive time stepping. This paper introduces an adaptive filter that controls spurious modes of the solution, but is not unnecessarily diffusive. Consequently we are able to stabilize the solution with larger time steps, but also take advantage of the accuracy of a high order filter.

  13. Time with Peers from Middle Childhood to Late Adolescence: Developmental Course and Adjustment Correlates

    PubMed Central

    Lam, Chun Bun; McHale, Susan M.; Crouter, Ann C.

    2014-01-01

    This study examined the developmental course and adjustment correlates of time with peers from age 8 to 18. On 7 occasions over 8 years, the two eldest siblings from 201 European American, working- and middle-class families provided questionnaire and/or phone diary data. Multilevel models revealed that girls’ time with mixed/opposite-sex peers increased beginning in middle childhood, but boys’ time increased beginning in early adolescence. For both girls and boys, time with same-sex peers peaked in mid-adolescence. At the within-person level, unsupervised time with mixed/opposite-sex peers longitudinally predicted problem behaviors and depressive symptoms, and supervised time with mixed/opposite-sex peers longitudinally predicted better school performance. Findings highlight the importance of social context in understanding peer involvement and its implications for youth development. PMID:24673293

  14. Step detection in single-molecule real time trajectories embedded in correlated noise.

    PubMed

    Arunajadai, Srikesh G; Cheng, Wei

    2013-01-01

    Single-molecule real time trajectories are embedded in high noise. To extract kinetic or dynamic information of the molecules from these trajectories often requires idealization of the data in steps and dwells. One major premise behind the existing single-molecule data analysis algorithms is the gaussian 'white' noise, which displays no correlation in time and whose amplitude is independent on data sampling frequency. This so-called 'white' noise is widely assumed but its validity has not been critically evaluated. We show that correlated noise exists in single-molecule real time trajectories collected from optical tweezers. The assumption of white noise during analysis of these data can lead to serious over- or underestimation of the number of steps depending on the algorithms employed. We present a statistical method that quantitatively evaluates the structure of the underlying noise, takes the noise structure into account, and identifies steps and dwells in a single-molecule trajectory. Unlike existing data analysis algorithms, this method uses Generalized Least Squares (GLS) to detect steps and dwells. Under the GLS framework, the optimal number of steps is chosen using model selection criteria such as Bayesian Information Criterion (BIC). Comparison with existing step detection algorithms showed that this GLS method can detect step locations with highest accuracy in the presence of correlated noise. Because this method is automated, and directly works with high bandwidth data without pre-filtering or assumption of gaussian noise, it may be broadly useful for analysis of single-molecule real time trajectories.

  15. Controlling Time-Dependent Confounding by Health Status and Frailty: Restriction Versus Statistical Adjustment.

    PubMed

    McGrath, Leah J; Ellis, Alan R; Brookhart, M Alan

    2015-07-01

    Nonexperimental studies of preventive interventions are often biased because of the healthy-user effect and, in frail populations, because of confounding by functional status. Bias is evident when estimating influenza vaccine effectiveness, even after adjustment for claims-based indicators of illness. We explored bias reduction methods while estimating vaccine effectiveness in a cohort of adult hemodialysis patients. Using the United States Renal Data System and linked data from a commercial dialysis provider, we estimated vaccine effectiveness using a Cox proportional hazards marginal structural model of all-cause mortality before and during 3 influenza seasons in 2005/2006 through 2007/2008. To improve confounding control, we added frailty indicators to the model, measured time-varying confounders at different time intervals, and restricted the sample in multiple ways. Crude and baseline-adjusted marginal structural models remained strongly biased. Restricting to a healthier population removed some unmeasured confounding; however, this reduced the sample size, resulting in wide confidence intervals. We estimated an influenza vaccine effectiveness of 9% (hazard ratio = 0.91, 95% confidence interval: 0.72, 1.15) when bias was minimized through cohort restriction. In this study, the healthy-user bias could not be controlled through statistical adjustment; however, sample restriction reduced much of the bias.

  16. Adjustment errors of sunstones in the first step of sky-polarimetric Viking navigation: studies with dichroic cordierite/ tourmaline and birefringent calcite crystals

    PubMed Central

    Száz, Dénes; Farkas, Alexandra; Blahó, Miklós; Barta, András; Egri, Ádám; Kretzer, Balázs; Hegedüs, Tibor; Jäger, Zoltán; Horváth, Gábor

    2016-01-01

    According to an old but still unproven theory, Viking navigators analysed the skylight polarization with dichroic cordierite or tourmaline, or birefringent calcite sunstones in cloudy/foggy weather. Combining these sunstones with their sun-dial, they could determine the position of the occluded sun, from which the geographical northern direction could be guessed. In psychophysical laboratory experiments, we studied the accuracy of the first step of this sky-polarimetric Viking navigation. We measured the adjustment error e of rotatable cordierite, tourmaline and calcite crystals when the task was to determine the direction of polarization of white light as a function of the degree of linear polarization p. From the obtained error functions e(p), the thresholds p* above which the first step can still function (i.e. when the intensity change seen through the rotating analyser can be sensed) were derived. Cordierite is about twice as reliable as tourmaline. Calcite sunstones have smaller adjustment errors if the navigator looks for that orientation of the crystal where the intensity difference between the two spots seen in the crystal is maximal, rather than minimal. For higher p (greater than pcrit) of incident light, the adjustment errors of calcite are larger than those of the dichroic cordierite (pcrit=20%) and tourmaline (pcrit=45%), while for lower p (less than pcrit) calcite usually has lower adjustment errors than dichroic sunstones. We showed that real calcite crystals are not as ideal sunstones as it was believed earlier, because they usually contain scratches, impurities and crystal defects which increase considerably their adjustment errors. Thus, cordierite and tourmaline can also be at least as good sunstones as calcite. Using the psychophysical e(p) functions and the patterns of the degree of skylight polarization measured by full-sky imaging polarimetry, we computed how accurately the northern direction can be determined with the use of the Viking sun

  17. Adjustment errors of sunstones in the first step of sky-polarimetric Viking navigation: studies with dichroic cordierite/ tourmaline and birefringent calcite crystals.

    PubMed

    Száz, Dénes; Farkas, Alexandra; Blahó, Miklós; Barta, András; Egri, Ádám; Kretzer, Balázs; Hegedüs, Tibor; Jäger, Zoltán; Horváth, Gábor

    2016-01-01

    According to an old but still unproven theory, Viking navigators analysed the skylight polarization with dichroic cordierite or tourmaline, or birefringent calcite sunstones in cloudy/foggy weather. Combining these sunstones with their sun-dial, they could determine the position of the occluded sun, from which the geographical northern direction could be guessed. In psychophysical laboratory experiments, we studied the accuracy of the first step of this sky-polarimetric Viking navigation. We measured the adjustment error e of rotatable cordierite, tourmaline and calcite crystals when the task was to determine the direction of polarization of white light as a function of the degree of linear polarization p. From the obtained error functions e(p), the thresholds p* above which the first step can still function (i.e. when the intensity change seen through the rotating analyser can be sensed) were derived. Cordierite is about twice as reliable as tourmaline. Calcite sunstones have smaller adjustment errors if the navigator looks for that orientation of the crystal where the intensity difference between the two spots seen in the crystal is maximal, rather than minimal. For higher p (greater than p crit) of incident light, the adjustment errors of calcite are larger than those of the dichroic cordierite (p crit=20%) and tourmaline (p crit=45%), while for lower p (less than p crit) calcite usually has lower adjustment errors than dichroic sunstones. We showed that real calcite crystals are not as ideal sunstones as it was believed earlier, because they usually contain scratches, impurities and crystal defects which increase considerably their adjustment errors. Thus, cordierite and tourmaline can also be at least as good sunstones as calcite. Using the psychophysical e(p) functions and the patterns of the degree of skylight polarization measured by full-sky imaging polarimetry, we computed how accurately the northern direction can be determined with the use of the Viking

  18. 26 CFR 1.754-1 - Time and manner of making election to adjust basis of partnership property.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Time and manner of making election to adjust..., Subchapter K, Chapter 1 of the Code § 1.754-1 Time and manner of making election to adjust basis of... sections 734(b) and 743(b) if it files an election in accordance with the rules set forth in paragraph...

  19. Effects of priming exercise on the speed of adjustment of muscle oxidative metabolism at the onset of moderate-intensity step transitions in older adults.

    PubMed

    De Roia, Gabriela; Pogliaghi, Silvia; Adami, Alessandra; Papadopoulou, Christina; Capelli, Carlo

    2012-05-15

    Aging is associated with a functional decline of the oxidative metabolism due to progressive limitations of both O(2) delivery and utilization. Priming exercise (PE) increases the speed of adjustment of oxidative metabolism during successive moderate-intensity transitions. We tested the hypothesis that such improvement is due to a better matching of O(2) delivery to utilization within the working muscles. In 21 healthy older adults (65.7 ± 5 yr), we measured contemporaneously noninvasive indexes of the overall speed of adjustment of the oxidative metabolism (i.e., pulmonary Vo(2) kinetics), of the bulk O(2) delivery (i.e., cardiac output), and of the rate of muscle deoxygenation (i.e., deoxygenated hemoglobin, HHb) during moderate-intensity step transitions, either with (ModB) or without (ModA) prior PE. The local matching of O(2) delivery to utilization was evaluated by the ΔHHb/ΔVo(2) ratio index. The overall speed of adjustment of the Vo(2) kinetics was significantly increased in ModB compared with ModA (P < 0.05). On the contrary, the kinetics of cardiac output was unaffected by PE. At the muscle level, ModB was associated with a significant reduction of the "overshoot" in the ΔHHb/ΔVo(2) ratio compared with ModA (P < 0.05), suggesting an improved O(2) delivery. Our data are compatible with the hypothesis that, in older adults, PE, prior to moderate-intensity exercise, beneficially affects the speed of adjustment of oxidative metabolism due to an acute improvement of the local matching of O(2) delivery to utilization.

  20. Calculating disability-adjusted-life-years lost (DALYs) in discrete-time.

    PubMed

    Larson, Bruce A

    2013-08-08

    Disability-adjusted-life-years lost (DALYs) is a common outcome metric for cost-effectiveness analyses, and the equations used for such calculations have been presented previously by Fox-Rushby and Hanson (see, e.g., "Health Policy and Planning 16:326-331, 2001"). While the equations are clear, the logic behind them is opaque at best for a large share of public health practitioners and students. The objective of this paper is to show how to calculate DALYs using a discrete time formulation that is easy to teach to students and public health practitioners, is easy to apply for those with basic discounting skills, and is consistent with the discounting methods typically included on the costing side of cost-effectiveness analysis. A continuous-time adjustment factor is derived that can be used to ensure exact consistency between the continuous and discrete time approaches, but this level of precision is typically unnecessary for cost-effectiveness analyses. To illustrate the approach, both a new, simple example and the same example presented in Fox-Rushby and Hanson are used throughout the paper.

  1. Multi time-step wavefront reconstruction for tomographic adaptive-optics systems.

    PubMed

    Ono, Yoshito H; Akiyama, Masayuki; Oya, Shin; Lardiére, Olivier; Andersen, David R; Correia, Carlos; Jackson, Kate; Bradley, Colin

    2016-04-01

    In tomographic adaptive-optics (AO) systems, errors due to tomographic wavefront reconstruction limit the performance and angular size of the scientific field of view (FoV), where AO correction is effective. We propose a multi time-step tomographic wavefront reconstruction method to reduce the tomographic error by using measurements from both the current and previous time steps simultaneously. We further outline the method to feed the reconstructor with both wind speed and direction of each turbulence layer. An end-to-end numerical simulation, assuming a multi-object AO (MOAO) system on a 30 m aperture telescope, shows that the multi time-step reconstruction increases the Strehl ratio (SR) over a scientific FoV of 10 arc min in diameter by a factor of 1.5-1.8 when compared to the classical tomographic reconstructor, depending on the guide star asterism and with perfect knowledge of wind speeds and directions. We also evaluate the multi time-step reconstruction method and the wind estimation method on the RAVEN demonstrator under laboratory setting conditions. The wind speeds and directions at multiple atmospheric layers are measured successfully in the laboratory experiment by our wind estimation method with errors below 2  ms-1. With these wind estimates, the multi time-step reconstructor increases the SR value by a factor of 1.2-1.5, which is consistent with a prediction from the end-to-end numerical simulation.

  2. Time Step Rescaling Recovers Continuous-Time Dynamical Properties for Discrete-Time Langevin Integration of Nonequilibrium Systems

    PubMed Central

    2015-01-01

    When simulating molecular systems using deterministic equations of motion (e.g., Newtonian dynamics), such equations are generally numerically integrated according to a well-developed set of algorithms that share commonly agreed-upon desirable properties. However, for stochastic equations of motion (e.g., Langevin dynamics), there is still broad disagreement over which integration algorithms are most appropriate. While multiple desiderata have been proposed throughout the literature, consensus on which criteria are important is absent, and no published integration scheme satisfies all desiderata simultaneously. Additional nontrivial complications stem from simulating systems driven out of equilibrium using existing stochastic integration schemes in conjunction with recently developed nonequilibrium fluctuation theorems. Here, we examine a family of discrete time integration schemes for Langevin dynamics, assessing how each member satisfies a variety of desiderata that have been enumerated in prior efforts to construct suitable Langevin integrators. We show that the incorporation of a novel time step rescaling in the deterministic updates of position and velocity can correct a number of dynamical defects in these integrators. Finally, we identify a particular splitting (related to the velocity Verlet discretization) that has essentially universally appropriate properties for the simulation of Langevin dynamics for molecular systems in equilibrium, nonequilibrium, and path sampling contexts. PMID:24555448

  3. Resuscitator’s perceptions and time for corrective ventilation steps during neonatal resuscitation☆

    PubMed Central

    Sharma, Vinay; Lakshminrusimha, Satyan; Carrion, Vivien; Mathew, Bobby

    2016-01-01

    Background The 2010 neonatal resuscitation program (NRP) guidelines incorporate ventilation corrective steps (using the mnemonic – MRSOPA) into the resuscitation algorithm. The perception of neonatal providers, time taken to perform these maneuvers or the effectiveness of these additional steps has not been evaluated. Methods Using two simulated clinical scenarios of varying degrees of cardiovascular compromise –perinatal asphyxia with (i) bradycardia (heart rate – 40 min−1) and (ii) cardiac arrest, 35 NRP certified providers were evaluated for preference to performing these corrective measures, the time taken for performing these steps and time to onset of chest compressions. Results The average time taken to perform ventilation corrective steps (MRSOPA) was 48.9 ± 21.4 s. Providers were less likely to perform corrective steps and proceed directly to endotracheal intubation in the scenario of cardiac arrest as compared to a state of bradycardia. Cardiac compressions were initiated significantly sooner in the scenario of cardiac arrest 89 ± 24 s as compared to severe bradycardia 122 ± 23 s, p < 0.0001. There were no differences in the time taken to initiation of chest compressions between physicians or mid-level care providers or with the level of experience of the provider. Conclusions Effective ventilation of the lungs with corrective steps using a mask is important in most cases of neonatal resuscitation. Neonatal resuscitators prefer early endotracheal intubation and initiation of chest compressions in the presence of asystolic cardiac arrest. Corrective ventilation steps can potentially postpone initiation of chest compressions and may delay return of spontaneous circulation in the presence of severe cardiovascular compromise. PMID:25796996

  4. The hyperbolic step potential: Anti-bound states, SUSY partners and Wigner time delays

    NASA Astrophysics Data System (ADS)

    Gadella, M.; Kuru, Ş.; Negro, J.

    2017-04-01

    We study the scattering produced by a one dimensional hyperbolic step potential, which is exactly solvable and shows an unusual interest because of its asymmetric character. The analytic continuation of the scattering matrix in the momentum representation has a branch cut and an infinite number of simple poles on the negative imaginary axis which are related with the so called anti-bound states. This model does not show resonances. Using the wave functions of the anti-bound states, we obtain supersymmetric (SUSY) partners which are the series of Rosen-Morse II potentials. We have computed the Wigner reflection and transmission time delays for the hyperbolic step and such SUSY partners. Our results show that the more bound states a partner Hamiltonian has the smaller is the time delay. We also have evaluated time delays for the hyperbolic step potential in the classical case and have obtained striking similitudes with the quantum case.

  5. Enabling fast, stable and accurate peridynamic computations using multi-time-step integration

    SciTech Connect

    Lindsay, P.; Parks, M. L.; Prakash, A.

    2016-04-13

    Peridynamics is a nonlocal extension of classical continuum mechanics that is well-suited for solving problems with discontinuities such as cracks. This paper extends the peridynamic formulation to decompose a problem domain into a number of smaller overlapping subdomains and to enable the use of different time steps in different subdomains. This approach allows regions of interest to be isolated and solved at a small time step for increased accuracy while the rest of the problem domain can be solved at a larger time step for greater computational efficiency. Lastly, performance of the proposed method in terms of stability, accuracy, and computational cost is examined and several numerical examples are presented to corroborate the findings.

  6. Boosting the accuracy and speed of quantum Monte Carlo: Size consistency and time step

    NASA Astrophysics Data System (ADS)

    Zen, Andrea; Sorella, Sandro; Gillan, Michael J.; Michaelides, Angelos; Alfè, Dario

    2016-06-01

    Diffusion Monte Carlo (DMC) simulations for fermions are becoming the standard for providing high-quality reference data in systems that are too large to be investigated via quantum chemical approaches. DMC with the fixed-node approximation relies on modifications of the Green's function to avoid singularities near the nodal surface of the trial wave function. Here we show that these modifications affect the DMC energies in a way that is not size consistent, resulting in large time-step errors. Building on the modifications of Umrigar et al. and DePasquale et al. we propose a simple Green's function modification that restores size consistency to large values of the time step, which substantially reduces time-step errors. This algorithm also yields remarkable speedups of up to two orders of magnitude in the calculation of molecule-molecule binding energies and crystal cohesive energies, thus extending the horizons of what is possible with DMC.

  7. Enabling fast, stable and accurate peridynamic computations using multi-time-step integration

    DOE PAGES

    Lindsay, P.; Parks, M. L.; Prakash, A.

    2016-04-13

    Peridynamics is a nonlocal extension of classical continuum mechanics that is well-suited for solving problems with discontinuities such as cracks. This paper extends the peridynamic formulation to decompose a problem domain into a number of smaller overlapping subdomains and to enable the use of different time steps in different subdomains. This approach allows regions of interest to be isolated and solved at a small time step for increased accuracy while the rest of the problem domain can be solved at a larger time step for greater computational efficiency. Lastly, performance of the proposed method in terms of stability, accuracy, andmore » computational cost is examined and several numerical examples are presented to corroborate the findings.« less

  8. Exponential time-differencing with embedded Runge–Kutta adaptive step control

    SciTech Connect

    Whalen, P.; Brio, M.; Moloney, J.V.

    2015-01-01

    We have presented the first embedded Runge–Kutta exponential time-differencing (RKETD) methods of fourth order with third order embedding and fifth order with third order embedding for non-Rosenbrock type nonlinear systems. A procedure for constructing RKETD methods that accounts for both order conditions and stability is outlined. In our stability analysis, the fast time scale is represented by a full linear operator in contrast to particular scalar cases considered before. An effective time-stepping strategy based on reducing both ETD function evaluations and rejected steps is described. Comparisons of performance with adaptive-stepping integrating factor (IF) are carried out on a set of canonical partial differential equations: the shock-fronts of Burgers equation, interacting KdV solitons, KS controlled chaos, and critical collapse of two-dimensional NLS.

  9. A self-adjusting compliant bilateral control scheme for time-delay teleoperation in constrained environment

    NASA Astrophysics Data System (ADS)

    Chen, Zhang; Liang, Bin; Zhang, Tao

    2016-05-01

    When teleoperations are implemented in the constrained environment, the lack of environment information would lead to contacts and undesired excessive contact forces, which are more evident with the existence of time delays. In this paper, a hybrid compliant bilateral controller is proposed to deal with this problem. The controller adopts a self-adjusting selecting scheme to divide the subspaces online. The master and slave manipulators are synchronized in the position subspace through an adaptive bilateral control scheme. At the same time, the slave manipulator is controlled by a local sliding mode impedance controller in order to achieve the desired compliant motion when contacting with the environment. Theoretical analysis proves the stability of the hybrid bilateral controller and concludes the transient performance of the teleoperators. Simulations are carried out to verify the effectiveness of the proposed approach. The results show that the control goals are all achieved.

  10. Sampling-time effects for persistence and survival in step structural fluctuations.

    PubMed

    Dougherty, D B; Tao, C; Bondarchuk, O; Cullen, W G; Williams, E D; Constantin, M; Dasgupta, C; Das Sarma, S

    2005-02-01

    The effects of sampling rate and total measurement time have been determined for single-point measurements of step fluctuations within the context of first-passage properties. Time dependent scanning tunneling microscopy has been used to evaluate step fluctuations on Ag(111) films grown on mica as a function of temperature (300-410 K) , on screw dislocations on the facets of Pb crystallites at 320 K , and on Al-terminated Si(111) over the temperature range 770-970 K . Although the fundamental time constant for step fluctuations on Ag and Al/Si varies by orders of magnitude over the temperature ranges of measurement, no dependence of the persistence amplitude on temperature is observed. Instead, the persistence probability is found to scale directly with t/delta t where delta t is the time interval used for sampling. Survival probabilities show a more complex scaling dependence, which includes both the sampling interval and the total measurement time t(m) . Scaling with t/delta t occurs only when delta t/ t(m) is a constant. We show that this observation is equivalent to theoretical predictions that the survival probability will scale as delta t/ L(z) , where L is the effective length of a step. This implies that the survival probability for large systems, when measured with fixed values of t(m) or delta t , should also show little or no temperature dependence.

  11. Time-step Considerations in Particle Simulation Algorithms for Coulomb Collisions in Plasmas

    SciTech Connect

    Cohen, B I; Dimits, A; Friedman, A; Caflisch, R

    2009-10-29

    The accuracy of first-order Euler and higher-order time-integration algorithms for grid-based Langevin equations collision models in a specific relaxation test problem is assessed. We show that statistical noise errors can overshadow time-step errors and argue that statistical noise errors can be conflated with time-step effects. Using a higher-order integration scheme may not achieve any benefit in accuracy for examples of practical interest. We also investigate the collisional relaxation of an initial electron-ion relative drift and the collisional relaxation to a resistive steady-state in which a quasi-steady current is driven by a constant applied electric field, as functions of the time step used to resolve the collision processes using binary and grid-based, test-particle Langevin equations models. We compare results from two grid-based Langevin equations collision algorithms to results from a binary collision algorithm for modeling electronion collisions. Some guidance is provided regarding how large a time step can be used compared to the inverse of the characteristic collision frequency for specific relaxation processes.

  12. The large discretization step method for time-dependent partial differential equations

    NASA Technical Reports Server (NTRS)

    Haras, Zigo; Taasan, Shlomo

    1995-01-01

    A new method for the acceleration of linear and nonlinear time dependent calculations is presented. It is based on the Large Discretization Step (LDS) approximation, defined in this work, which employs an extended system of low accuracy schemes to approximate a high accuracy discrete approximation to a time dependent differential operator. Error bounds on such approximations are derived. These approximations are efficiently implemented in the LDS methods for linear and nonlinear hyperbolic equations, presented here. In these algorithms the high and low accuracy schemes are interpreted as the same discretization of a time dependent operator on fine and coarse grids, respectively. Thus, a system of correction terms and corresponding equations are derived and solved on the coarse grid to yield the fine grid accuracy. These terms are initialized by visiting the fine grid once in many coarse grid time steps. The resulting methods are very general, simple to implement and may be used to accelerate many existing time marching schemes.

  13. Effects of Timing of Adversity on Adolescent and Young Adult Adjustment

    ERIC Educational Resources Information Center

    Kiff, Cara J.; Cortes, Rebecca C.; Lengua, Liliana J.; Kosterman, Rick; Hawkins, J. David; Mason, W. Alex

    2012-01-01

    Exposure to adversity during childhood and adolescence predicts adjustment across development. Furthermore, adolescent adjustment problems persist into young adulthood. This study examined relations of contextual adversity with concurrent adolescent adjustment and prospective mental health and health outcomes in young adulthood. A longitudinal…

  14. Use of age-adjusted rates of suicide in time series studies in Israel.

    PubMed

    Bridges, F Stephen; Tankersley, William B

    2009-01-01

    Durkheim's modified theory of suicide was examined to explore how consistent it was in predicting Israeli rates of suicide from 1965 to 1997 when using age-adjusted rates rather than crude ones. In this time-series study, Israeli male and female rates of suicide increased and decreased, respectively, between 1965 and 1997. Conforming to Durkheim's modified theory, the Israeli male rate of suicide was lower in years when rates of marriage and birth are higher, while rates of suicide are higher in years when rates of divorce are higher, the opposite to that of Israeli women. The corrected regression coefficients suggest that the Israeli female rate of suicide remained lower in years when rate of divorce is higher, again the opposite suggested by Durkheim's modified theory. These results may indicate that divorce affects the mental health of Israeli women as suggested by their lower rate of suicide. Perhaps the "multiple roles held by Israeli females creates suicidogenic stress" and divorce provides some sense of stress relief, mentally speaking. The results were not as consistent with predictions suggested by Durkheim's modified theory of suicide as were rates from the United States for the same period nor were they consistent with rates based on "crude" suicide data. Thus, using age-adjusted rates of suicide had an influence on the prediction of the Israeli rate of suicide during this period.

  15. Validation and comparison of shank and lumbar-worn IMUs for step time estimation.

    PubMed

    Johnston, William; Patterson, Matthew; O'Mahony, Niamh; Caulfield, Brian

    2016-12-21

    Gait assessment is frequently used as an outcome measure to determine changes in an individual's mobility and disease processes. Inertial measurement units (IMUs) are quickly becoming commonplace in gait analysis. The purpose of this study was to determine and compare the validity of shank and lumbar IMU mounting locations in the estimation of temporal gait features. Thirty-seven adults performed 20 walking trials each over a gold standard force platform while wearing shank and lumbar-mounted IMUs. Data from the IMUs were used to estimate step times using previously published algorithms and were compared with those derived from the force platform. There was an excellent level of correlation between the force platform and shank (r=0.95) and lumbar-mounted (r=0.99) IMUs. Bland-Altman analysis demonstrated high levels of agreement between the IMU and the force platform step times. Confidence interval widths were 0.0782 s for the shank and 0.0367 s for the lumbar. Both IMU mounting locations provided accurate step time estimations, with the lumbar demonstrating a marginally superior level of agreement with the force platform. This validation indicates that the IMU system is capable of providing step time estimates within 2% of the gold standard force platform measurement.

  16. Time-Delayed Two-Step Selective Laser Photodamage of Dye-Biomolecule Complexes

    NASA Astrophysics Data System (ADS)

    Andreoni, A.; Cubeddu, R.; de Silvestri, S.; Laporta, P.; Svelto, O.

    1980-08-01

    A scheme is proposed for laser-selective photodamage of biological molecules, based on time-delayed two-step photoionization of a dye molecule bound to the biomolecule. The validity of the scheme is experimentally demonstrated in the case of the dye Proflavine, bound to synthetic polynucleotides.

  17. Making Progress in Mental Health Policy in Conservative Times: One Step at a Time

    PubMed Central

    Goldman, Howard H.

    2006-01-01

    Progress in mental health services has been made incrementally in a sequence of policy steps. In recent years, in spite of political conservatism, progressive changes have advanced new principles of service delivery. Reports from the surgeon general and the President's New Freedom Commission on Mental Health advanced these principles, including recovery and evidence-based practices. Both of these high-level reports were influenced by the findings of the Schizophrenia Patient Outcomes Research Team (PORT). The Schizophrenia PORT established the effectiveness of mental health treatments and supports, which provided a scientific foundation for the optimistic focus on recovery and its expectation of improved outcomes for individuals with severe mental disorders. The PORT study also established the gap between treatment recommendations and actual services. Concern about this gap has motivated efforts to transform services by implementing evidence-based practices. Advances in broad mental health and social policy, coupled with continued advances in science, have the potential to improve the care of individuals who experience severe mental disorders, such as schizophrenia. PMID:16436626

  18. TACImager: a high frame rate 320 x 256 SPAD time to amplitude converter array with adjustable time zoom

    NASA Astrophysics Data System (ADS)

    Finlayson, Neil; Parmesan, Luca; Dutton, Neale A. W.; Calder, Neil J.; Henderson, Robert K.

    2016-10-01

    Single-photon avalanche diodes (SPADs) in the form of high-resolution imaging pixel arrays are used in 3D cameras, motion-tracking, biomedical and time-correlated single photon counting (TCSPC) applications. Rapid spatial and temporal zoom onto objects of interest is an attractive feature. We present here novel high-speed time-zoom functionality achieved with the digital readout mode of the TACImager, a 256 x 256 TCSPC image sensor array based on sample and hold Time to Amplitude Converter (TAC) pixels. A column-parallel flash Analogue to Digital Converter (ADC) is implemented in the TACImager to support fast digital readout, allowing per-pixel, 3-bin TCSPC histogramming at frame rates of 4 kfps. New results related to this high-speed mode of operation are presented. The TACImager utilises a global ramp voltage as a timing reference, allowing time-zoom to be achieved through dynamic adjustment of comparator voltages, ramp offset voltages and ramp waveforms. We demonstrate the influence of fixed pattern noise in the pixels and column parallel ADCs on the results.

  19. Promoting rest using a quiet time innovation in an adult neuroscience step down unit.

    PubMed

    Bergner, Tara

    2014-01-01

    Sleep and rest are fundamental for the restoration of energy needed to recuperate from illness, trauma and surgery. At present hospitals are too noisy to promote rest for patients. A literature search produced research that described how quiet time interventions addressing noise levels have met with positive patient and staff satisfaction, as well as creating a more peaceful and healing environment. In this paper, a description of the importance of quiet time and how a small butfeasible innovation was carried out in an adult neuroscience step down unit in a large tertiary health care facility in Canada is provided. Anecdotal evidence from patients, families, and staff suggests that quiet time may have positive effects for patients, their families, and the adult neuroscience step down unit staff Future research examining the effect of quiet time on patient, family and staff satisfaction and patient healing is necessary.

  20. A multiple time stepping algorithm for efficient multiscale modeling of platelets flowing in blood plasma

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Zhang, Na; Deng, Yuefan; Bluestein, Danny

    2015-03-01

    We developed a multiple time-stepping (MTS) algorithm for multiscale modeling of the dynamics of platelets flowing in viscous blood plasma. This MTS algorithm improves considerably the computational efficiency without significant loss of accuracy. This study of the dynamic properties of flowing platelets employs a combination of the dissipative particle dynamics (DPD) and the coarse-grained molecular dynamics (CGMD) methods to describe the dynamic microstructures of deformable platelets in response to extracellular flow-induced stresses. The disparate spatial scales between the two methods are handled by a hybrid force field interface. However, the disparity in temporal scales between the DPD and CGMD that requires time stepping at microseconds and nanoseconds respectively, represents a computational challenge that may become prohibitive. Classical MTS algorithms manage to improve computing efficiency by multi-stepping within DPD or CGMD for up to one order of magnitude of scale differential. In order to handle 3-4 orders of magnitude disparity in the temporal scales between DPD and CGMD, we introduce a new MTS scheme hybridizing DPD and CGMD by utilizing four different time stepping sizes. We advance the fluid system at the largest time step, the fluid-platelet interface at a middle timestep size, and the nonbonded and bonded potentials of the platelet structural system at two smallest timestep sizes. Additionally, we introduce parameters to study the relationship of accuracy versus computational complexities. The numerical experiments demonstrated 3000x reduction in computing time over standard MTS methods for solving the multiscale model. This MTS algorithm establishes a computationally feasible approach for solving a particle-based system at multiple scales for performing efficient multiscale simulations.

  1. A Multiple Time Stepping Algorithm for Efficient Multiscale Modeling of Platelets Flowing in Blood Plasma.

    PubMed

    Zhang, Peng; Zhang, Na; Deng, Yuefan; Bluestein, Danny

    2015-03-01

    We developed a multiple time-stepping (MTS) algorithm for multiscale modeling of the dynamics of platelets flowing in viscous blood plasma. This MTS algorithm improves considerably the computational efficiency without significant loss of accuracy. This study of the dynamic properties of flowing platelets employs a combination of the dissipative particle dynamics (DPD) and the coarse-grained molecular dynamics (CGMD) methods to describe the dynamic microstructures of deformable platelets in response to extracellular flow-induced stresses. The disparate spatial scales between the two methods are handled by a hybrid force field interface. However, the disparity in temporal scales between the DPD and CGMD that requires time stepping at microseconds and nanoseconds respectively, represents a computational challenge that may become prohibitive. Classical MTS algorithms manage to improve computing efficiency by multi-stepping within DPD or CGMD for up to one order of magnitude of scale differential. In order to handle 3-4 orders of magnitude disparity in the temporal scales between DPD and CGMD, we introduce a new MTS scheme hybridizing DPD and CGMD by utilizing four different time stepping sizes. We advance the fluid system at the largest time step, the fluid-platelet interface at a middle timestep size, and the nonbonded and bonded potentials of the platelet structural system at two smallest timestep sizes. Additionally, we introduce parameters to study the relationship of accuracy versus computational complexities. The numerical experiments demonstrated 3000x reduction in computing time over standard MTS methods for solving the multiscale model. This MTS algorithm establishes a computationally feasible approach for solving a particle-based system at multiple scales for performing efficient multiscale simulations.

  2. A Multiple Time Stepping Algorithm for Efficient Multiscale Modeling of Platelets Flowing in Blood Plasma

    PubMed Central

    Zhang, Peng; Zhang, Na; Deng, Yuefan; Bluestein, Danny

    2015-01-01

    We developed a multiple time-stepping (MTS) algorithm for multiscale modeling of the dynamics of platelets flowing in viscous blood plasma. This MTS algorithm improves considerably the computational efficiency without significant loss of accuracy. This study of the dynamic properties of flowing platelets employs a combination of the dissipative particle dynamics (DPD) and the coarse-grained molecular dynamics (CGMD) methods to describe the dynamic microstructures of deformable platelets in response to extracellular flow-induced stresses. The disparate spatial scales between the two methods are handled by a hybrid force field interface. However, the disparity in temporal scales between the DPD and CGMD that requires time stepping at microseconds and nanoseconds respectively, represents a computational challenge that may become prohibitive. Classical MTS algorithms manage to improve computing efficiency by multi-stepping within DPD or CGMD for up to one order of magnitude of scale differential. In order to handle 3–4 orders of magnitude disparity in the temporal scales between DPD and CGMD, we introduce a new MTS scheme hybridizing DPD and CGMD by utilizing four different time stepping sizes. We advance the fluid system at the largest time step, the fluid-platelet interface at a middle timestep size, and the nonbonded and bonded potentials of the platelet structural system at two smallest timestep sizes. Additionally, we introduce parameters to study the relationship of accuracy versus computational complexities. The numerical experiments demonstrated 3000x reduction in computing time over standard MTS methods for solving the multiscale model. This MTS algorithm establishes a computationally feasible approach for solving a particle-based system at multiple scales for performing efficient multiscale simulations. PMID:25641983

  3. Dynamic Adjustment of Stimuli in Real Time Functional Magnetic Resonance Imaging

    PubMed Central

    Feng, I. Jung; Jack, Anthony I.; Tatsuoka, Curtis

    2015-01-01

    The conventional fMRI image analysis approach to associating stimuli to brain activation is performed by carrying out a massive number of parallel univariate regression analyses. fMRI blood-oxygen-level dependent (BOLD) signal, the basis of these analyses, is known for its low signal-noise-ratio and high spatial and temporal signal correlation. In order to ensure accurate localization of brain activity, stimulus administration in an fMRI session is often lengthy and repetitive. Real-time fMRI BOLD signal analysis is carried out as the signal is observed. This method allows for dynamic, real-time adjustment of stimuli through sequential experimental designs. We have developed a voxel-wise sequential probability ratio test (SPRT) approach for dynamically determining localization, as well as decision rules for stopping stimulus administration. SPRT methods and general linear model (GLM) approaches are combined to identify brain regions that are activated by specific elements of stimuli. Stimulus administration is dynamically stopped when sufficient statistical evidence is collected to determine activation status across regions of interest, following predetermined statistical error thresholds. Simulation experiments and an example based on real fMRI data show that scan volumes can be substantially reduced when compared with pre-determined, fixed designs while achieving similar or better accuracy in detecting activated voxels. Moreover, the proposed approach is also able to accurately detect differentially activated areas, and other comparisons between task-related GLM parameters that can be formulated in a hypothesis-testing framework. Finally, we give a demonstration of SPRT being employed in conjunction with a halving algorithm to dynamically adjust stimuli. PMID:25785856

  4. An implicit time-stepping scheme for rigid body dynamics with Coulomb friction

    SciTech Connect

    STEWART,DAVID; TRINKLE,JEFFREY C.

    2000-02-15

    In this paper a new time-stepping method for simulating systems of rigid bodies is given. Unlike methods which take an instantaneous point of view, the method is based on impulse-momentum equations, and so does not need to explicitly resolve impulsive forces. On the other hand, the method is distinct from previous impulsive methods in that it does not require explicit collision checking and it can handle simultaneous impacts. Numerical results are given for one planar and one three-dimensional example, which demonstrate the practicality of the method, and its convergence as the step size becomes small.

  5. Cortical delta activity reflects reward prediction error and related behavioral adjustments, but at different times.

    PubMed

    Cavanagh, James F

    2015-04-15

    Recent work has suggested that reward prediction errors elicit a positive voltage deflection in the scalp-recorded electroencephalogram (EEG); an event sometimes termed a reward positivity. However, a strong test of this proposed relationship remains to be defined. Other important questions remain unaddressed: such as the role of the reward positivity in predicting future behavioral adjustments that maximize reward. To answer these questions, a three-armed bandit task was used to investigate the role of positive prediction errors during trial-by-trial exploration and task-set based exploitation. The feedback-locked reward positivity was characterized by delta band activities, and these related EEG features scaled with the degree of a computationally derived positive prediction error. However, these phenomena were also dissociated: the computational model predicted exploitative action selection and related response time speeding whereas the feedback-locked EEG features did not. Compellingly, delta band dynamics time-locked to the subsequent bandit (the P3) successfully predicted these behaviors. These bandit-locked findings included an enhanced parietal to motor cortex delta phase lag that correlated with the degree of response time speeding, suggesting a mechanistic role for delta band activities in motivating action selection. This dissociation in feedback vs. bandit locked EEG signals is interpreted as a differentiation in hierarchically distinct types of prediction error, yielding novel predictions about these dissociable delta band phenomena during reinforcement learning and decision making.

  6. Development of a real time activity monitoring Android application utilizing SmartStep.

    PubMed

    Hegde, Nagaraj; Melanson, Edward; Sazonov, Edward

    2016-08-01

    Footwear based activity monitoring systems are becoming popular in academic research as well as consumer industry segments. In our previous work, we had presented developmental aspects of an insole based activity and gait monitoring system-SmartStep, which is a socially acceptable, fully wireless and versatile insole. The present work describes the development of an Android application that captures the SmartStep data wirelessly over Bluetooth Low energy (BLE), computes features on the received data, runs activity classification algorithms and provides real time feedback. The development of activity classification methods was based on the the data from a human study involving 4 participants. Participants were asked to perform activities of sitting, standing, walking, and cycling while they wore SmartStep insole system. Multinomial Logistic Discrimination (MLD) was utilized in the development of machine learning model for activity prediction. The resulting classification model was implemented in an Android Smartphone. The Android application was benchmarked for power consumption and CPU loading. Leave one out cross validation resulted in average accuracy of 96.9% during model training phase. The Android application for real time activity classification was tested on a human subject wearing SmartStep resulting in testing accuracy of 95.4%.

  7. Stance time variability during stair stepping before and after total knee arthroplasty: a pilot study

    PubMed Central

    Smith, Jessica W.; Marcus, Robin L.; Tracy, Brian L.; Foreman, K. Bo; Christensen, Jesse C.; LaStayo, Paul C.

    2015-01-01

    The main objectives of this pilot study were to: 1) investigate stance time variability (STV) during stair stepping in older adults with osteoarthritis (OA) before and after total knee arthroplasty (TKA), and compare to an age- and sex-matched group of healthy controls with native knees and 2) evaluate the relationship between quadriceps strength and STV during stair stepping before and after TKA. A prospective, observational, pilot study was carried out on 13 individuals (15% male, mean age 62.71 ± 6.84 years) before and after TKA using an instrumented stairway, patient-reported outcomes, timed stair stepping test, and quadriceps strength measures. At 6-months post-operatively, STV during stair descent was significantly greater in the TKA-GROUP compared to the CONTROL-GROUP, but was not significantly different at 12-months compared to controls. There were no significant differences in STV for stair ascent between the pre- and post-operative visits, or compared to controls. There was a trend toward significance for the relationship between quadriceps strength and STV during stair ascent (P=0.059) and descent (P=0.073). Variability during stair stepping may provide an important, short-term rehabilitation target for individuals following TKA and may represent another parameter to predict declines in functional mobility. PMID:26590484

  8. High-Order Implicit-Explicit Multi-Block Time-stepping Method for Hyperbolic PDEs

    NASA Technical Reports Server (NTRS)

    Nielsen, Tanner B.; Carpenter, Mark H.; Fisher, Travis C.; Frankel, Steven H.

    2014-01-01

    This work seeks to explore and improve the current time-stepping schemes used in computational fluid dynamics (CFD) in order to reduce overall computational time. A high-order scheme has been developed using a combination of implicit and explicit (IMEX) time-stepping Runge-Kutta (RK) schemes which increases numerical stability with respect to the time step size, resulting in decreased computational time. The IMEX scheme alone does not yield the desired increase in numerical stability, but when used in conjunction with an overlapping partitioned (multi-block) domain significant increase in stability is observed. To show this, the Overlapping-Partition IMEX (OP IMEX) scheme is applied to both one-dimensional (1D) and two-dimensional (2D) problems, the nonlinear viscous Burger's equation and 2D advection equation, respectively. The method uses two different summation by parts (SBP) derivative approximations, second-order and fourth-order accurate. The Dirichlet boundary conditions are imposed using the Simultaneous Approximation Term (SAT) penalty method. The 6-stage additive Runge-Kutta IMEX time integration schemes are fourth-order accurate in time. An increase in numerical stability 65 times greater than the fully explicit scheme is demonstrated to be achievable with the OP IMEX method applied to 1D Burger's equation. Results from the 2D, purely convective, advection equation show stability increases on the order of 10 times the explicit scheme using the OP IMEX method. Also, the domain partitioning method in this work shows potential for breaking the computational domain into manageable sizes such that implicit solutions for full three-dimensional CFD simulations can be computed using direct solving methods rather than the standard iterative methods currently used.

  9. The Semi-implicit Time-stepping Algorithm in MH4D

    NASA Astrophysics Data System (ADS)

    Vadlamani, Srinath; Shumlak, Uri; Marklin, George; Meier, Eric; Lionello, Roberto

    2006-10-01

    The Plasma Science and Innovation Center (PSI Center) at the University of Washington is developing MHD codes to accurately model Emerging Concept (EC) devices. Examination of the semi-implicit time stepping algorithm implemented in the tetrahedral mesh MHD simulation code, MH4D, is presented. The time steps for standard explicit methods, which are constrained by the Courant-Friedrichs-Lewy (CFL) condition, are typically small for simulations of EC experiments due to the large Alfven speed. The CFL constraint is more severe with a tetrahedral mesh because of the irregular cell geometry. The semi-implicit algorithm [1] removes the fast waves constraint, thus allowing for larger time steps. We will present the implementation method of this algorithm, and numerical results for test problems in simple geometry. Also, we will present the effectiveness in simulations of complex geometry, similar to the ZaP [2] experiment at the University of Washington. References: [1]Douglas S. Harned and D. D. Schnack, Semi-implicit method for long time scale magnetohy drodynamic computations in three dimensions, JCP, Volume 65, Issue 1, July 1986, Pages 57-70. [2]U. Shumlak, B. A. Nelson, R. P. Golingo, S. L. Jackson, E. A. Crawford, and D. J. Den Hartog, Sheared flow stabilization experiments in the ZaP flow Zpinch, Phys. Plasmas 10, 1683 (2003).

  10. On large time step TVD scheme for hyperbolic conservation laws and its efficiency evaluation

    NASA Astrophysics Data System (ADS)

    Qian, ZhanSen; Lee, Chun-Hian

    2012-08-01

    A large time step (LTS) TVD scheme originally proposed by Harten is modified and further developed in the present paper and applied to Euler equations in multidimensional problems. By firstly revealing the drawbacks of Harten's original LTS TVD scheme, and reasoning the occurrence of the spurious oscillations, a modified formulation of its characteristic transformation is proposed and a high resolution, strongly robust LTS TVD scheme is formulated. The modified scheme is proven to be capable of taking larger number of time steps than the original one. Following the modified strategy, the LTS TVD schemes for Yee's upwind TVD scheme and Yee-Roe-Davis's symmetric TVD scheme are constructed. The family of the LTS schemes is then extended to multidimensional by time splitting procedure, and the associated boundary condition treatment suitable for the LTS scheme is also imposed. The numerical experiments on Sod's shock tube problem, inviscid flows over NACA0012 airfoil and ONERA M6 wing are performed to validate the developed schemes. Computational efficiencies for the respective schemes under different CFL numbers are also evaluated and compared. The results reveal that the improvement is sizable as compared to the respective single time step schemes, especially for the CFL number ranging from 1.0 to 4.0.

  11. Rapid Adjustment of Circadian Clocks to Simulated Travel to Time Zones across the Globe.

    PubMed

    Harrison, Elizabeth M; Gorman, Michael R

    2015-12-01

    Daily rhythms in mammalian physiology and behavior are generated by a central pacemaker located in the hypothalamic suprachiasmatic nuclei (SCN), the timing of which is set by light from the environment. When the ambient light-dark cycle is shifted, as occurs with travel across time zones, the SCN and its output rhythms must reset or re-entrain their phases to match the new schedule-a sluggish process requiring about 1 day per hour shift. Using a global assay of circadian resetting to 6 equidistant time-zone meridians, we document this characteristically slow and distance-dependent resetting of Syrian hamsters under typical laboratory lighting conditions, which mimic summer day lengths. The circadian pacemaker, however, is additionally entrainable with respect to its waveform (i.e., the shape of the 24-h oscillation) allowing for tracking of seasonally varying day lengths. We here demonstrate an unprecedented, light exposure-based acceleration in phase resetting following 2 manipulations of circadian waveform. Adaptation of circadian waveforms to long winter nights (8 h light, 16 h dark) doubled the shift response in the first 3 days after the shift. Moreover, a bifurcated waveform induced by exposure to a novel 24-h light-dark-light-dark cycle permitted nearly instant resetting to phase shifts from 4 to 12 h in magnitude, representing a 71% reduction in the mismatch between the activity rhythm and the new photocycle. Thus, a marked enhancement of phase shifting can be induced via nonpharmacological, noninvasive manipulation of the circadian pacemaker waveform in a model species for mammalian circadian rhythmicity. Given the evidence of conserved flexibility in the human pacemaker waveform, these findings raise the promise of flexible resetting applicable to circadian disruption in shift workers, frequent time-zone travelers, and any individual forced to adjust to challenging schedules.

  12. Error correction in short time steps during the application of quantum gates

    SciTech Connect

    Castro, L.A. de Napolitano, R.D.J.

    2016-04-15

    We propose a modification of the standard quantum error-correction method to enable the correction of errors that occur due to the interaction with a noisy environment during quantum gates without modifying the codification used for memory qubits. Using a perturbation treatment of the noise that allows us to separate it from the ideal evolution of the quantum gate, we demonstrate that in certain cases it is necessary to divide the logical operation in short time steps intercalated by correction procedures. A prescription of how these gates can be constructed is provided, as well as a proof that, even for the cases when the division of the quantum gate in short time steps is not necessary, this method may be advantageous for reducing the total duration of the computation.

  13. Explicit large time-step schemes for the shallow water equations

    NASA Technical Reports Server (NTRS)

    Turkel, E.; Zwas, G.

    1979-01-01

    Modifications to explicit finite difference schemes for solving the shallow water equations for meteorological applications by increasing the time step for the fast gravity waves are analyzed. Terms associated with the gravity waves in the shallow water equations are treated on a coarser grid than those associated with the slow Rossby waves, which contain much more of the available energy and must be treated with higher accuracy, enabling a several-fold increase in time step without degrading the accuracy of the solution. The method is presented in Cartesian and spherical coordinates for a rotating earth, using generalized leapfrog, frozen coefficient, and Fourier filtering finite difference schemes. Computational results verify the numerical stability of the approach.

  14. Implementation of variable time step stochastic dynamics for electronically inelastic gas-surface collisions

    NASA Technical Reports Server (NTRS)

    Garrett, Bruce C.; Swaminathan, P. K.; Murthy, C. S.; Redmon, Michael J.

    1987-01-01

    A variable time step algorithm has been implemented for solving the stochastic equations of motion for gas-surface collisions. It has been tested for a simple model of electronically inelastic collisions with an insulator surface in which the phonon manifold acts as a heat bath and electronic states are localized. In addition to reproducing the accurate nuclear dynamics of the surface atoms, numerical calculations have shown the algorithm to yield accurate ensemble averages of physical observables such as electronic transition probabilities and total energy loss of the gas atom to the surface. This new algorithm offers a gain in efficieny of up to an order of magnitude compared to fixed time step integration.

  15. Accuracy of Pedometer Steps and Time for Youth with Intellectual Disabilities during Dynamic Movements

    ERIC Educational Resources Information Center

    Pitetti, Kenneth H.; Beets, Michael W.; Flaming, Judy

    2009-01-01

    Pedometer accuracy for steps and activity time during dynamic movement for youth with intellectual disabilities (ID) were examined. Twenty-four youth with ID (13 girls, 13.1 [plus or minus] 3.2 yrs; 11 boys, 14.7 [plus or minus] 2.7 yrs) were videotaped during adapted physical education class while wearing a Walk4Life 2505 pedometer in five…

  16. Multiple Time-Step Dual-Hamiltonian Hybrid Molecular Dynamics — Monte Carlo Canonical Propagation Algorithm

    PubMed Central

    Weare, Jonathan; Dinner, Aaron R.; Roux, Benoît

    2016-01-01

    A multiple time-step integrator based on a dual Hamiltonian and a hybrid method combining molecular dynamics (MD) and Monte Carlo (MC) is proposed to sample systems in the canonical ensemble. The Dual Hamiltonian Multiple Time-Step (DHMTS) algorithm is based on two similar Hamiltonians: a computationally expensive one that serves as a reference and a computationally inexpensive one to which the workload is shifted. The central assumption is that the difference between the two Hamiltonians is slowly varying. Earlier work has shown that such dual Hamiltonian multiple time-step schemes effectively precondition nonlinear differential equations for dynamics by reformulating them into a recursive root finding problem that can be solved by propagating a correction term through an internal loop, analogous to RESPA. Of special interest in the present context, a hybrid MD-MC version of the DHMTS algorithm is introduced to enforce detailed balance via a Metropolis acceptance criterion and ensure consistency with the Boltzmann distribution. The Metropolis criterion suppresses the discretization errors normally associated with the propagation according to the computationally inexpensive Hamiltonian, treating the discretization error as an external work. Illustrative tests are carried out to demonstrate the effectiveness of the method. PMID:26918826

  17. A chaos detectable and time step-size adaptive numerical scheme for nonlinear dynamical systems

    NASA Astrophysics Data System (ADS)

    Chen, Yung-Wei; Liu, Chein-Shan; Chang, Jiang-Ren

    2007-02-01

    The first step in investigation the dynamics of a continuous time system described by ordinary differential equations is to integrate them to obtain trajectories. In this paper, we convert the group-preserving scheme (GPS) developed by Liu [International Journal of Non-Linear Mechanics 36 (2001) 1047-1068] to a time step-size adaptive scheme, x=x+hf(x,t), where x∈R is the system variables we are concerned with, and f(x,t)∈R is a time-varying vector field. The scheme has the form similar to the Euler scheme, x=x+Δtf(x,t), but our step-size h is adaptive automatically. Very interestingly, the ratio h/Δt, which we call the adaptive factor, can forecast the appearance of chaos if the considered dynamical system becomes chaotical. The numerical examples of the Duffing equation, the Lorenz equation and the Rossler equation, which may exhibit chaotic behaviors under certain parameters values, are used to demonstrate these phenomena. Two other non-chaotic examples are included to compare the performance of the GPS and the adaptive one.

  18. Variable time-stepping in the pathwise numerical solution of the chemical Langevin equation.

    PubMed

    Ilie, Silvana

    2012-12-21

    Stochastic modeling is essential for an accurate description of the biochemical network dynamics at the level of a single cell. Biochemically reacting systems often evolve on multiple time-scales, thus their stochastic mathematical models manifest stiffness. Stochastic models which, in addition, are stiff and computationally very challenging, therefore the need for developing effective and accurate numerical methods for approximating their solution. An important stochastic model of well-stirred biochemical systems is the chemical Langevin Equation. The chemical Langevin equation is a system of stochastic differential equation with multidimensional non-commutative noise. This model is valid in the regime of large molecular populations, far from the thermodynamic limit. In this paper, we propose a variable time-stepping strategy for the numerical solution of a general chemical Langevin equation, which applies for any level of randomness in the system. Our variable stepsize method allows arbitrary values of the time-step. Numerical results on several models arising in applications show significant improvement in accuracy and efficiency of the proposed adaptive scheme over the existing methods, the strategies based on halving/doubling of the stepsize and the fixed step-size ones.

  19. A conservative finite volume scheme with time-accurate local time stepping for scalar transport on unstructured grids

    NASA Astrophysics Data System (ADS)

    Cavalcanti, José Rafael; Dumbser, Michael; Motta-Marques, David da; Fragoso Junior, Carlos Ruberto

    2015-12-01

    In this article we propose a new conservative high resolution TVD (total variation diminishing) finite volume scheme with time-accurate local time stepping (LTS) on unstructured grids for the solution of scalar transport problems, which are typical in the context of water quality simulations. To keep the presentation of the new method as simple as possible, the algorithm is only derived in two space dimensions and for purely convective transport problems, hence neglecting diffusion and reaction terms. The new numerical method for the solution of the scalar transport is directly coupled to the hydrodynamic model of Casulli and Walters (2000) that provides the dynamics of the free surface and the velocity vector field based on a semi-implicit discretization of the shallow water equations. Wetting and drying is handled rigorously by the nonlinear algorithm proposed by Casulli (2009). The new time-accurate LTS algorithm allows a different time step size for each element of the unstructured grid, based on an element-local Courant-Friedrichs-Lewy (CFL) stability condition. The proposed method does not need any synchronization between different time steps of different elements and is by construction locally and globally conservative. The LTS scheme is based on a piecewise linear polynomial reconstruction in space-time using the MUSCL-Hancock method, to obtain second order of accuracy in both space and time. The new algorithm is first validated on some classical test cases for pure advection problems, for which exact solutions are known. In all cases we obtain a very good level of accuracy, showing also numerical convergence results; we furthermore confirm mass conservation up to machine precision and observe an improved computational efficiency compared to a standard second order TVD scheme for scalar transport with global time stepping (GTS). Then, the new LTS method is applied to some more complex problems, where the new scalar transport scheme has also been coupled to

  20. The forward and adjoint sensitivity methods of glacial isostatic adjustment: Existence, uniqueness and time-differencing scheme

    NASA Astrophysics Data System (ADS)

    Martinec, Zdenek; Sasgen, Ingo; Velimsky, Jakub

    2014-05-01

    In this study, two new methods for computing the sensitivity of the glacial isostatic adjustment (GIA) forward solution with respect to the Earth's mantle viscosity are presented: the forward sensitivity method (FSM) and the adjoint sensitivity method (ASM). These advanced formal methods are based on the time-domain,spectral-finite element method for modelling the GIA response of laterally heterogeneous earth models developed by Martinec (2000). There are many similarities between the forward method and the FSM and ASM for a general physical system. However, in the case of GIA, there are also important differences between the forward and sensitivity methods. The analysis carried out in this study results in the following findings. First, the forward method of GIA is unconditionally solvable, regardless of whether or not a combined ice and ocean-water load contains the first-degree spherical harmonics. This is also the case for the FSM, however, the ASM must in addition be supplemented by nine conditions on the misfit between the given GIA-related data and the forward model predictions to guarantee the existence of a solution. This constrains the definition of data least-squares misfit. Second, the forward method of GIA implements an ocean load as a free boundary-value function over an ocean area with a free geometry. That is, an ocean load and the shape of ocean, the so-called ocean function, are being sought, in addition to deformation and gravity-increment fields, by solving the forward method. The FSM and ASM also apply the adjoint ocean load as a free boundary-value function, but instead over an ocean area with the fixed geometry given by the ocean function determined by the forward method. In other words, a boundary-value problem for the forward method of GIA is free with respect to determining (i) the boundary-value data over an ocean area and (ii) the ocean function itself, while the boundary-value problems for the FSM and ASM are free only with respect to

  1. Real-time, single-step bioassay using nanoplasmonic resonator with ultra-high sensitivity

    DOEpatents

    Zhang, Xiang; Ellman, Jonathan A; Chen, Fanqing Frank; Su, Kai-Hang; Wei, Qi-Huo; Sun, Cheng

    2014-04-01

    A nanoplasmonic resonator (NPR) comprising a metallic nanodisk with alternating shielding layer(s), having a tagged biomolecule conjugated or tethered to the surface of the nanoplasmonic resonator for highly sensitive measurement of enzymatic activity. NPRs enhance Raman signals in a highly reproducible manner, enabling fast detection of protease and enzyme activity, such as Prostate Specific Antigen (paPSA), in real-time, at picomolar sensitivity levels. Experiments on extracellular fluid (ECF) from paPSA-positive cells demonstrate specific detection in a complex bio-fluid background in real-time single-step detection in very small sample volumes.

  2. Real-Time, Single-Step Bioassay Using Nanoplasmonic Resonator With Ultra-High Sensitivity

    NASA Technical Reports Server (NTRS)

    Zhang, Xiang (Inventor); Ellman, Jonathan A. (Inventor); Chen, Fanqing Frank (Inventor); Su, Kai-Hang (Inventor); Wei, Qi-Huo (Inventor); Sun, Cheng (Inventor)

    2014-01-01

    A nanoplasmonic resonator (NPR) comprising a metallic nanodisk with alternating shielding layer(s), having a tagged biomolecule conjugated or tethered to the surface of the nanoplasmonic resonator for highly sensitive measurement of enzymatic activity. NPRs enhance Raman signals in a highly reproducible manner, enabling fast detection of protease and enzyme activity, such as Prostate Specific Antigen (paPSA), in real-time, at picomolar sensitivity levels. Experiments on extracellular fluid (ECF) from paPSA-positive cells demonstrate specific detection in a complex bio-fluid background in real-time single-step detection in very small sample volumes.

  3. The timing of the Black Sea flood event: Insights from modeling of glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    Goldberg, Samuel L.; Lau, Harriet C. P.; Mitrovica, Jerry X.; Latychev, Konstantin

    2016-10-01

    We present a suite of gravitationally self-consistent predictions of sea-level change since Last Glacial Maximum (LGM) in the vicinity of the Bosphorus and Dardanelles straits that combine signals associated with glacial isostatic adjustment (GIA) and the flooding of the Black Sea. Our predictions are tuned to fit a relative sea level (RSL) record at the island of Samothrace in the north Aegean Sea and they include realistic 3-D variations in viscoelastic structure, including lateral variations in mantle viscosity and the elastic thickness of the lithosphere, as well as weak plate boundary zones. We demonstrate that 3-D Earth structure and the magnitude of the flood event (which depends on the pre-flood level of the lake) both have significant impact on the predicted RSL change at the location of the Bosphorus sill, and therefore on the inferred timing of the marine incursion. We summarize our results in a plot showing the predicted RSL change at the Bosphorus sill as a function of the timing of the flood event for different flood magnitudes up to 100 m. These results suggest, for example, that a flood event at 9 ka implies that the elevation of the sill was lowered through erosion by ∼14-21 m during, and after, the flood. In contrast, a flood event at 7 ka suggests erosion of ∼24-31 m at the sill since the flood. More generally, our results will be useful for future research aimed at constraining the details of this controversial, and widely debated geological event.

  4. NONINDEPENDENT AND NONSTATIONARY RESPONSE TIMES IN STOPPING AND STEPPING SACCADE TASKS

    PubMed Central

    Nelson, Matthew J.; Boucher, Leanne; Logan, Gordon D.; Palmeri, Thomas J.; Schall, Jeffrey D.

    2011-01-01

    Saccade stop-signal and target-step tasks are used to investigate the mechanisms of cognitive control. Performance of these tasks can be explained as the outcome of a race between stochastic GO and STOP processes. The race-model analyses assume that response times (RTs) measured throughout an experimental session are independent samples from stationary stochastic processes. This article demonstrates that RTs are neither independent nor stationary for humans and monkeys performing saccade stopping and target-step tasks. We investigate the consequences this has on analyses of these data. Nonindependent and nonstationary RTs artificially flatten inhibition functions and account for some of the systematic differences in RTs following different types of trials. However, nonindependent and nonstationary RTs do not bias the estimation of the stop-signal RT. These results demonstrate the robustness of the race model to some aspects of nonindependence and nonstationarity, and point to useful extensions of the model. PMID:20952788

  5. Real‐time monitoring and control of the load phase of a protein A capture step

    PubMed Central

    Rüdt, Matthias; Brestrich, Nina; Rolinger, Laura

    2016-01-01

    ABSTRACT The load phase in preparative Protein A capture steps is commonly not controlled in real‐time. The load volume is generally based on an offline quantification of the monoclonal antibody (mAb) prior to loading and on a conservative column capacity determined by resin‐life time studies. While this results in a reduced productivity in batch mode, the bottleneck of suitable real‐time analytics has to be overcome in order to enable continuous mAb purification. In this study, Partial Least Squares Regression (PLS) modeling on UV/Vis absorption spectra was applied to quantify mAb in the effluent of a Protein A capture step during the load phase. A PLS model based on several breakthrough curves with variable mAb titers in the HCCF was successfully calibrated. The PLS model predicted the mAb concentrations in the effluent of a validation experiment with a root mean square error (RMSE) of 0.06 mg/mL. The information was applied to automatically terminate the load phase, when a product breakthrough of 1.5 mg/mL was reached. In a second part of the study, the sensitivity of the method was further increased by only considering small mAb concentrations in the calibration and by subtracting an impurity background signal. The resulting PLS model exhibited a RMSE of prediction of 0.01 mg/mL and was successfully applied to terminate the load phase, when a product breakthrough of 0.15 mg/mL was achieved. The proposed method has hence potential for the real‐time monitoring and control of capture steps at large scale production. This might enhance the resin capacity utilization, eliminate time‐consuming offline analytics, and contribute to the realization of continuous processing. Biotechnol. Bioeng. 2017;114: 368–373. © 2016 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals, Inc. PMID:27543789

  6. Predictive wall adjustment strategy for two-dimensional flexible walled adaptive wind tunnel: A detailed description of the first one-step method

    NASA Technical Reports Server (NTRS)

    Wolf, Stephen W. D.; Goodyer, Michael J.

    1988-01-01

    Following the realization that a simple iterative strategy for bringing the flexible walls of two-dimensional test sections to streamline contours was too slow for practical use, Judd proposed, developed, and placed into service what was the first Predictive Strategy. The Predictive Strategy reduced by 75 percent or more the number of iterations of wall shapes, and therefore the tunnel run-time overhead attributable to the streamlining process, required to reach satisfactory streamlines. The procedures of the Strategy are embodied in the FORTRAN subroutine WAS (standing for Wall Adjustment Strategy) which is written in general form. The essentials of the test section hardware, followed by the underlying aerodynamic theory which forms the basis of the Strategy, are briefly described. The subroutine is then presented as the Appendix, broken down into segments with descriptions of the numerical operations underway in each, with definitions of variables.

  7. Sensitivity of The High-resolution Wam Model With Respect To Time Step

    NASA Astrophysics Data System (ADS)

    Kasemets, K.; Soomere, T.

    The northern part of the Baltic Proper and its subbasins (Bothnian Sea, the Gulf of Finland, Moonsund) serve as a challenge for wave modellers. In difference from the southern and the eastern parts of the Baltic Sea, their coasts are highly irregular and contain many peculiarities with the characteristic horizontal scale of the order of a few kilometres. For example, the northern coast of the Gulf of Finland is extremely ragged and contains a huge number of small islands. Its southern coast is more or less regular but has up to 50m high cliff that is frequently covered by high forests. The area also contains numerous banks that have water depth a couple of meters and that may essentially modify wave properties near the banks owing to topographical effects. This feature suggests that a high-resolution wave model should be applied for the region in question, with a horizontal resolution of an order of 1 km or even less. According to the Courant-Friedrich-Lewy criterion, the integration time step for such models must be of the order of a few tens of seconds. A high-resolution WAM model turns out to be fairly sensitive with respect to the particular choice of the time step. In our experiments, a medium-resolution model for the whole Baltic Sea was used, with the horizontal resolution 3 miles (3' along latitudes and 6' along longitudes) and the angular resolution 12 directions. The model was run with steady wind blowing 20 m/s from different directions and with two time steps (1 and 3 minutes). For most of the wind directions, the rms. difference of significant wave heights calculated with differ- ent time steps did not exceed 10 cm and typically was of the order of a few per cents. The difference arose within a few tens of minutes and generally did not increase in further computations. However, in the case of the north wind, the difference increased nearly monotonously and reached 25-35 cm (10-15%) within three hours of integra- tion whereas mean of significant wave

  8. Positive change following adversity and psychological adjustment over time in abused foster youth.

    PubMed

    Valdez, Christine E; Lim, Ban Hong Phylice; Parker, Christopher P

    2015-10-01

    Many foster youth experience maltreatment in their family-of-origin and additional maltreatment while in foster care. Not surprisingly, rates of depression are higher in foster youth than the general population, and peak during ages 17-19 during the stressful transition into adulthood. However, no known studies have reported on whether foster youth perceive positive changes following such adversity, and whether positive change facilitates psychological adjustment over time. The current study examined components of positive change (i.e., compassion for others and self-efficacy) with depression severity from age 17 to 18 as youth prepared to exit foster care. Participants were youth from the Mental Health Service Use of Youth Leaving Foster Care study who endorsed child maltreatment. Components of positive change and severity of abuse were measured initially. Depression was measured initially and every three months over the following year. Latent growth curve modeling was used to examine the course of depression as a function of initial levels of positive change and severity of abuse. Results revealed that decreases in depression followed an inverse quadratic function in which the steepest declines occurred in the first three months and leveled off after that. Severity of abuse was positively correlated with higher initial levels of depression and negatively correlated with decreases in depression. Greater self-efficacy was negatively associated with initial levels of depression and predicted decreases in depression over the year, whereas compassion for others was neither associated with initial depression nor changes in depression. Implications for intervention, theory, and research are discussed.

  9. Large time-step stability of explicit one-dimensional advection schemes

    NASA Technical Reports Server (NTRS)

    Leonard, B. P.

    1993-01-01

    There is a wide-spread belief that most explicit one-dimensional advection schemes need to satisfy the so-called 'CFL condition' - that the Courant number, c = udelta(t)/delta(x), must be less than or equal to one, for stability in the von Neumann sense. This puts severe limitations on the time-step in high-speed, fine-grid calculations and is an impetus for the development of implicit schemes, which often require less restrictive time-step conditions for stability, but are more expensive per time-step. However, it turns out that, at least in one dimension, if explicit schemes are formulated in a consistent flux-based conservative finite-volume form, von Neumann stability analysis does not place any restriction on the allowable Courant number. Any explicit scheme that is stable for c is less than 1, with a complex amplitude ratio, G(c), can be easily extended to arbitrarily large c. The complex amplitude ratio is then given by exp(- (Iota)(Nu)(Theta)) G(delta(c)), where N is the integer part of c, and delta(c) = c - N (less than 1); this is clearly stable. The CFL condition is, in fact, not a stability condition at all, but, rather, a 'range restriction' on the 'pieces' in a piece-wise polynomial interpolation. When a global view is taken of the interpolation, the need for a CFL condition evaporates. A number of well-known explicit advection schemes are considered and thus extended to large delta(t). The analysis also includes a simple interpretation of (large delta(t)) total-variation-diminishing (TVD) constraints.

  10. A class of large time step Godunov schemes for hyperbolic conservation laws and applications

    NASA Astrophysics Data System (ADS)

    Qian, ZhanSen; Lee, Chun-Hian

    2011-08-01

    A large time step (LTS) Godunov scheme firstly proposed by LeVeque is further developed in the present work and applied to Euler equations. Based on the analysis of the computational performances of LeVeque's linear approximation on wave interactions, a multi-wave approximation on rarefaction fan is proposed to avoid the occurrences of rarefaction shocks in computations. The developed LTS scheme is validated using 1-D test cases, manifesting high resolution for discontinuities and the capability of maintaining computational stability when large CFL numbers are imposed. The scheme is then extended to multidimensional problems using dimensional splitting technique; the treatment of boundary condition for this multidimensional LTS scheme is also proposed. As for demonstration problems, inviscid flows over NACA0012 airfoil and ONERA M6 wing with given swept angle are simulated using the developed LTS scheme. The numerical results reveal the high resolution nature of the scheme, where the shock can be captured within 1-2 grid points. The resolution of the scheme would improve gradually along with the increasing of CFL number under an upper bound where the solution becomes severely oscillating across the shock. Computational efficiency comparisons show that the developed scheme is capable of reducing the computational time effectively with increasing the time step (CFL number).

  11. Imaginary Time Step Method to Solve the Dirac Equation with Nonlocal Potential

    SciTech Connect

    Zhang Ying; Liang Haozhao; Meng Jie

    2009-08-26

    The imaginary time step (ITS) method is applied to solve the Dirac equation with nonlocal potentials in coordinate space. Taking the nucleus {sup 12}C as an example, even with nonlocal potentials, the direct ITS evolution for the Dirac equation still meets the disaster of the Dirac sea. However, following the recipe in our former investigation, the disaster can be avoided by the ITS evolution for the corresponding Schroedinger-like equation without localization, which gives the convergent results exactly the same with those obtained iteratively by the shooting method with localized effective potentials.

  12. A simple method for improving the time-stepping accuracy in atmosphere and ocean models

    NASA Astrophysics Data System (ADS)

    Williams, P. D.

    2012-12-01

    In contemporary numerical simulations of the atmosphere and ocean, evidence suggests that time-stepping errors may be a significant component of total model error, on both weather and climate time-scales. This presentation will review the available evidence, and will then suggest a simple but effective method for substantially improving the time-stepping numerics at no extra computational expense. A common time-stepping method in atmosphere and ocean models is the leapfrog scheme combined with the Robert-Asselin (RA) filter. This method is used in the following models (and many more): ECHAM, MAECHAM, MM5, CAM, MESO-NH, HIRLAM, KMCM, LIMA, SPEEDY, IGCM, PUMA, COSMO, FSU-GSM, FSU-NRSM, NCEP-GFS, NCEP-RSM, NSEAM, NOGAPS, RAMS, and CCSR/NIES-AGCM. Although the RA filter controls the time-splitting instability, it also introduces non-physical damping and reduces the accuracy. This presentation proposes a simple modification to the RA filter, which has become known as the RAW filter (Williams 2009, 2011). When used in conjunction with the leapfrog scheme, the RAW filter eliminates the non-physical damping and increases the amplitude accuracy by two orders, yielding third-order accuracy. (The phase accuracy remains second-order.) The RAW filter can easily be incorporated into existing models, typically via the insertion of just a single line of code. Better simulations are obtained at no extra computational expense. Results will be shown from recent implementations of the RAW filter in various models, including SPEEDY and COSMO. For example, in SPEEDY, the skill of weather forecasts is found to be significantly improved. In particular, in tropical surface pressure predictions, five-day forecasts made using the RAW filter have approximately the same skill as four-day forecasts made using the RA filter (Amezcua, Kalnay & Williams 2011). These improvements are encouraging for the use of the RAW filter in other atmosphere and ocean models. References PD Williams (2009) A

  13. One-Step Direct Aeroacoustic Simulation Using Space-Time Conservation Element and Solution Element Method

    NASA Astrophysics Data System (ADS)

    Ho, C. Y.; Leung, R. C. K.; Zhou, K.; Lam, G. C. Y.; Jiang, Z.

    2011-09-01

    One-step direct aeroacoustic simulation (DAS) has received attention from aerospace and mechanical high-pressure fluid-moving system manufacturers for quite some time. They aim to simulate the unsteady flow and acoustic field in the duct simultaneously in order to investigate the aeroacoustic generation mechanisms. Because of the large length and energy scale disparities between the acoustic far field and the aerodynamic near field, highly accurate and high-resolution simulation scheme is required. This involves the use of high order compact finite difference and time advancement schemes in simulation. However, in this situation, large buffer zones are always needed to suppress the spurious numerical waves emanating from computational boundaries. This further increases the computational resources to yield accurate results. On the other hand, for such problem as supersonic jet noise, the numerical scheme should be able to resolve both strong shock waves and weak acoustic waves simultaneously. Usually numerical aeroa-coustic scheme that is good for low Mach number flow is not able to give satisfactory simulation results for shock wave. Therefore, the aeroacoustic research community has been looking for a more efficient one-step DAS scheme that has the comparable accuracy to the finite-difference approach with smaller buffer regions, yet is able to give accurate solutions from subsonic to supersonic flows. The conservation element and solution element (CE/SE) scheme is one of the possible schemes satisfying the above requirements. This paper aims to report the development of a CE/SE scheme for one-step DAS and illustrate its robustness and effectiveness with two selected benchmark problems.

  14. Different Patterns of Sexual Identity Development over Time: Implications for the Psychological Adjustment of Lesbian, Gay, and Bisexual Youths

    PubMed Central

    Rosario, Margaret; Schrimshaw, Eric W.; Hunter, Joyce

    2010-01-01

    Despite research documenting variability in the sexual identity development of lesbian, gay, and bisexual (LGB) youths, it remains unclear whether different developmental patterns have implications for the psychological adjustment of LGB youths. The current report longitudinally examines whether different patterns of LGB identity formation and integration are associated with indicators of psychological adjustment among an ethnically diverse sample of 156 LGB youths (ages 14 – 21) in New York City. Although differences in the timing of identity formation were not associated with psychological adjustment, greater identity integration was related to less depressive and anxious symptoms, fewer conduct problems, and higher self-esteem both cross-sectionally and longitudinally. Individual changes in identity integration over time were associated with all four aspects of psychological adjustment, even after controlling for rival hypotheses concerning family and friend support, gay-related stress, negative social relationships, and other covariates. These findings suggest that difficulties in developing an integrated LGB identity may have negative implications for the psychological adjustment of LGB youths and that efforts to reduce distress among LGB youths should address the youths’ identity integration. PMID:19916104

  15. Pseudo-time stepping methods for space time discontinuous Galerkin discretizations of the compressible Navier Stokes equations

    NASA Astrophysics Data System (ADS)

    Klaij, C. M.; van der Vegt, J. J. W.; van der Ven, H.

    2006-12-01

    The space-time discontinuous Galerkin discretization of the compressible Navier-Stokes equations results in a non-linear system of algebraic equations, which we solve with pseudo-time stepping methods. We show that explicit Runge-Kutta methods developed for the Euler equations suffer from a severe stability constraint linked to the viscous part of the equations and propose an alternative to relieve this constraint while preserving locality. To evaluate its effectiveness, we compare with an implicit-explicit Runge-Kutta method which does not suffer from the viscous stability constraint. We analyze the stability of the methods and illustrate their performance by computing the flow around a 2D airfoil and a 3D delta wing at low and moderate Reynolds numbers.

  16. Detection of Zika virus by SYBR green one-step real-time RT-PCR.

    PubMed

    Xu, Ming-Yue; Liu, Si-Qing; Deng, Cheng-Lin; Zhang, Qiu-Yan; Zhang, Bo

    2016-10-01

    The ongoing Zika virus (ZIKV) outbreak has rapidly spread to new areas of Americas, which were the first transmissions outside its traditional endemic areas in Africa and Asia. Due to the link with newborn defects and neurological disorder, numerous infected cases throughout the world and various mosquito vectors, the virus has been considered to be an international public health emergency. In the present study, we developed a SYBR Green based one-step real-time RT-PCR assay for rapid detection of ZIKV. Our results revealed that the real-time assay is highly specific and sensitive in detection of ZIKV in cell samples. Importantly, the replication of ZIKV at different time points in infected cells could be rapidly monitored by the real-time RT-PCR assay. Specifically, the real-time RT-PCR showed acceptable performance in measurement of infectious ZIKV RNA. This assay could detect ZIKV at a titer as low as 1PFU/mL. The real-time RT-PCR assay could be a useful tool for further virology surveillance and diagnosis of ZIKV.

  17. Mentoring, Competencies, and Adjustment in Adolescents: American Part-Time Employment and European Apprenticeships

    ERIC Educational Resources Information Center

    Vazsonyi, Alexander T.; Snider, J. Blake

    2008-01-01

    Based on the conceptual argument that the European apprenticeship might explain cross-national variability in adolescent adjustment, the current investigation tested the relationships between mentoring experiences, namely joint activities with mentors as well as perceived mentoring behaviors by unrelated adults in the work setting, and measures of…

  18. Covariate Adjustment Strategy Increases Power in the Randomized Controlled Trial With Discrete-Time Survival Endpoints

    ERIC Educational Resources Information Center

    Safarkhani, Maryam; Moerbeek, Mirjam

    2013-01-01

    In a randomized controlled trial, a decision needs to be made about the total number of subjects for adequate statistical power. One way to increase the power of a trial is by including a predictive covariate in the model. In this article, the effects of various covariate adjustment strategies on increasing the power is studied for discrete-time…

  19. A matter of timing: developmental theories of romantic involvement and psychosocial adjustment.

    PubMed

    Furman, Wyndol; Collibee, Charlene

    2014-11-01

    The present study compared two theories of the association between romantic involvement and adjustment: a social timetable theory and a developmental task theory. We examined seven waves of longitudinal data on a community based sample of 200 participants (Wave 1 mean age = 15 years, 10 months). In each wave, multiple measures of substance use, externalizing symptoms, and internalizing symptoms were gathered, typically from multiple reporters. Multilevel modeling revealed that greater levels of romantic involvement in adolescence were associated with higher levels of substance use and externalizing symptoms but became associated with lower levels in adulthood. Having a romantic partner was associated with greater levels of substance use, externalizing symptoms, and internalizing symptoms in adolescence but was associated with lower levels in young adulthood. The findings were not consistent with a social timetable theory, which predicts that nonnormative involvement is associated with poor adjustment. Instead, the findings are consistent with a developmental task theory, which predicts that precocious romantic involvement undermines development and adaptation, but when romantic involvement becomes a salient developmental task in adulthood, it is associated with positive adjustment. Discussion focuses on the processes that may underlie the changing nature of the association between romantic involvement and adjustment.

  20. Multi-rate time stepping schemes for hydro-geomechanical model for subsurface methane hydrate reservoirs

    NASA Astrophysics Data System (ADS)

    Gupta, Shubhangi; Wohlmuth, Barbara; Helmig, Rainer

    2016-05-01

    We present an extrapolation-based semi-implicit multi-rate time stepping (MRT) scheme and a compound-fast MRT scheme for a naturally partitioned, multi-time-scale hydro-geomechanical hydrate reservoir model. We evaluate the performance of the two MRT methods compared to an iteratively coupled solution scheme and discuss their advantages and disadvantages. The performance of the two MRT methods is evaluated in terms of speed-up and accuracy by comparison to an iteratively coupled solution scheme. We observe that the extrapolation-based semi-implicit method gives a higher speed-up but is strongly dependent on the relative time scales of the latent (slow) and active (fast) components. On the other hand, the compound-fast method is more robust and less sensitive to the relative time scales, but gives lower speed up as compared to the semi-implicit method, especially when the relative time scales of the active and latent components are comparable.

  1. Nonparametric randomization-based covariate adjustment for stratified analysis of time-to-event or dichotomous outcomes.

    PubMed

    Hussey, Michael A; Koch, Gary G; Preisser, John S; Saville, Benjamin R

    2016-01-01

    Time-to-event or dichotomous outcomes in randomized clinical trials often have analyses using the Cox proportional hazards model or conditional logistic regression, respectively, to obtain covariate-adjusted log hazard (or odds) ratios. Nonparametric Randomization-Based Analysis of Covariance (NPANCOVA) can be applied to unadjusted log hazard (or odds) ratios estimated from a model containing treatment as the only explanatory variable. These adjusted estimates are stratified population-averaged treatment effects and only require a valid randomization to the two treatment groups and avoid key modeling assumptions (e.g., proportional hazards in the case of a Cox model) for the adjustment variables. The methodology has application in the regulatory environment where such assumptions cannot be verified a priori. Application of the methodology is illustrated through three examples on real data from two randomized trials.

  2. Antecedents of maternal parenting stress: the role of attachment style, prenatal attachment, and dyadic adjustment in first-time mothers

    PubMed Central

    Mazzeschi, Claudia; Pazzagli, Chiara; Radi, Giulia; Raspa, Veronica; Buratta, Livia

    2015-01-01

    The transition to parenthood is widely considered a period of increased vulnerability often accompanied by stress. Abidin conceived parenting stress as referring to specific difficulties in adjusting to the parenting role. Most studies of psychological distress arising from the demands of parenting have investigated the impact of stress on the development of dysfunctional parent–child relationships and on adult and child psychopathology. Studies have largely focused on mothers’ postnatal experience; less attention has been devoted to maternal prenatal characteristics associated with subsequent parental stress and studies of maternal prenatal predictors are few. Furthermore, no studies have examined that association exclusively with samples of first-time mothers. With an observational prospective study design with two time periods, the aim of this study was to investigate the role of mothers’ attachment style, maternal prenatal attachment to the fetus and dyadic adjustment during pregnancy (7th months of gestation) and their potential unique contribution to parenting stress 3 months after childbirth in a sample of nulliparous women. Results showed significant correlations between antenatal measures. Maternal attachment style (especially relationship anxiety) was negatively correlated with prenatal attachment and with dyadic adjustment; positive correlations resulted between prenatal attachment and dyadic adjustment. Each of the investigated variables was also good predictor of parenting stress 3 months after childbirth. Findings suggested how these dimensions could be considered as risk factors in the transition to motherhood and in the very beginning of the emergence of the caregiving system, especially with first-time mothers. PMID:26441808

  3. Time-Accurate Local Time Stepping and High-Order Time CESE Methods for Multi-Dimensional Flows Using Unstructured Meshes

    NASA Technical Reports Server (NTRS)

    Chang, Chau-Lyan; Venkatachari, Balaji Shankar; Cheng, Gary

    2013-01-01

    With the wide availability of affordable multiple-core parallel supercomputers, next generation numerical simulations of flow physics are being focused on unsteady computations for problems involving multiple time scales and multiple physics. These simulations require higher solution accuracy than most algorithms and computational fluid dynamics codes currently available. This paper focuses on the developmental effort for high-fidelity multi-dimensional, unstructured-mesh flow solvers using the space-time conservation element, solution element (CESE) framework. Two approaches have been investigated in this research in order to provide high-accuracy, cross-cutting numerical simulations for a variety of flow regimes: 1) time-accurate local time stepping and 2) highorder CESE method. The first approach utilizes consistent numerical formulations in the space-time flux integration to preserve temporal conservation across the cells with different marching time steps. Such approach relieves the stringent time step constraint associated with the smallest time step in the computational domain while preserving temporal accuracy for all the cells. For flows involving multiple scales, both numerical accuracy and efficiency can be significantly enhanced. The second approach extends the current CESE solver to higher-order accuracy. Unlike other existing explicit high-order methods for unstructured meshes, the CESE framework maintains a CFL condition of one for arbitrarily high-order formulations while retaining the same compact stencil as its second-order counterpart. For large-scale unsteady computations, this feature substantially enhances numerical efficiency. Numerical formulations and validations using benchmark problems are discussed in this paper along with realistic examples.

  4. Towards a comprehensive framework for cosimulation of dynamic models with an emphasis on time stepping

    NASA Astrophysics Data System (ADS)

    Hoepfer, Matthias

    co-simulation approach to modeling and simulation. It lays out the general approach to dynamic system co-simulation, and gives a comprehensive overview of what co-simulation is and what it is not. It creates a taxonomy of the requirements and limits of co-simulation, and the issues arising with co-simulating sub-models. Possible solutions towards resolving the stated problems are investigated to a certain depth. A particular focus is given to the issue of time stepping. It will be shown that for dynamic models, the selection of the simulation time step is a crucial issue with respect to computational expense, simulation accuracy, and error control. The reasons for this are discussed in depth, and a time stepping algorithm for co-simulation with unknown dynamic sub-models is proposed. Motivations and suggestions for the further treatment of selected issues are presented.

  5. [Photodissociation of Acetylene and Acetone using Step-Scan Time-Resolved FTIR Emission Spectroscopy

    NASA Technical Reports Server (NTRS)

    McLaren, Ian A.; Wrobel, Jacek D.

    1997-01-01

    The photodissociation of acetylene and acetone was investigated as a function of added quenching gas pressures using step-scan time-resolved FTIR emission spectroscopy. Its main components consist of Bruker IFS88, step-scan Fourier Transform Infrared (FTIR) spectrometer coupled to a flow cell equipped with Welsh collection optics. Vibrationally excited C2H radicals were produced from the photodissociation of acetylene in the unfocused experiments. The infrared (IR) emission from these excited C2H radicals was investigated as a function of added argon pressure. Argon quenching rate constants for all C2H emission bands are of the order of 10(exp -13)cc/molecule.sec. Quenching of these radicals by acetylene is efficient, with a rate constant in the range of 10(exp -11) cc/molecule.sec. The relative intensity of the different C2H emission bands did not change with the increasing argon or acetylene pressure. However, the overall IR emission intensity decreased, for example, by more than 50% when the argon partial pressure was raised from 0.2 to 2 Torr at fixed precursor pressure of 160mTorr. These observations provide evidence for the formation of a metastable C2H2 species, which are collisionally quenched by argon or acetylene. Problems encountered in the course of the experimental work are also described.

  6. Two step transfer entropy - An estimator of delayed directional couplings between multivariate EEG time series.

    PubMed

    Songhorzadeh, Maryam; Ansari-Asl, Karim; Mahmoudi, Alimorad

    2016-12-01

    Quantifying delayed directional couplings between electroencephalographic (EEG) time series requires an efficient method of causal network inference. This is especially due to the limited knowledge about the underlying dynamics of the brain activity. Recent methods based on information theoretic measures such as Transfer Entropy (TE) made significant progress on this issue by providing a model-free framework for causality detection. However, TE estimation from observed data is not a trivial task, especially when the number of variables is large which is the case in a highly complex system like human brain. Here we propose a computationally efficient procedure for TE estimation based on using sets of the Most Informative Variables that effectively contribute to resolving the uncertainty of the destination. In the first step of this method, some conditioning sets are determined through a nonlinear state space reconstruction; then in the second step, optimal estimation of TE is done based on these sets. Validation of the proposed method using synthetic data and neurophysiological signals demonstrates computational efficiency in quantifying delayed directional couplings compared with the common TE analysis.

  7. Adolescents’ relationship with God and internalizing adjustment over time: The moderating role of maternal religious coping

    PubMed Central

    Goeke-Morey, Marcie C.; Taylor, Laura K.; Merrilees, Christine E.; Shirlow, Peter; Cummings, E. Mark

    2015-01-01

    A growing literature supports the importance of understanding the link between religiosity and youths’ adjustment and development, but in the absence of rigorous, longitudinal designs, questions remain about the direction of effect and the role of family factors. This paper investigates the bi-directional association between adolescents’ relationship with God and their internalizing adjustment. Results from two-wave, SEM cross-lag analyses of data from 667 mother/adolescent dyads in Belfast, Northern Ireland (50% male, M age = 15.75 years old) supports a risk model suggesting that greater internalizing problems predicts a weaker relationship with God one year later. Significant moderation analyses suggest that a stronger relationship with God predicted fewer depression and anxiety symptoms for youth whose mothers used more religious coping. PMID:24955590

  8. Adolescents' relationship with God and internalizing adjustment over time: the moderating role of maternal religious coping.

    PubMed

    Goeke-Morey, Marcie C; Taylor, Laura K; Merrilees, Christine E; Shirlow, Peter; Cummings, E Mark

    2014-12-01

    A growing literature supports the importance of understanding the link between religiosity and youths' adjustment and development, but in the absence of rigorous, longitudinal designs, questions remain about the direction of effect and the role of family factors. This paper investigates the bidirectional association between adolescents' relationship with God and their internalizing adjustment. Results from 2-wave, SEM cross-lag analyses of data from 667 mother/adolescent dyads in Belfast, Northern Ireland (50% male, M age = 15.75 years old) supports a risk model suggesting that greater internalizing problems predict a weaker relationship with God 1 year later. Significant moderation analyses suggest that a stronger relationship with God predicted fewer depression and anxiety symptoms for youth whose mothers used more religious coping.

  9. Incorporating system latency associated with real-time target tracking radiotherapy in the dose prediction step

    NASA Astrophysics Data System (ADS)

    Roland, Teboh; Mavroidis, Panayiotis; Shi, Chengyu; Papanikolaou, Nikos

    2010-05-01

    System latency introduces geometric errors in the course of real-time target tracking radiotherapy. This effect can be minimized, for example by the use of predictive filters, but cannot be completely avoided. In this work, we present a convolution technique that can incorporate the effect as part of the treatment planning process. The method can be applied independently or in conjunction with the predictive filters to compensate for residual latency effects. The implementation was performed on TrackBeam (Initia Ltd, Israel), a prototype real-time target tracking system assembled and evaluated at our Cancer Institute. For the experimental system settings examined, a Gaussian distribution attributable to the TrackBeam latency was derived with σ = 3.7 mm. The TrackBeam latency, expressed as an average response time, was deduced to be 172 ms. Phantom investigations were further performed to verify the convolution technique. In addition, patient studies involving 4DCT volumes of previously treated lung cancer patients were performed to incorporate the latency effect in the dose prediction step. This also enabled us to effectively quantify the dosimetric and radiobiological impact of the TrackBeam and other higher latency effects on the clinical outcome of a real-time target tracking delivery.

  10. Simulations of precipitation using the Community Earth System Model (CESM): Sensitivity to microphysics time step

    NASA Astrophysics Data System (ADS)

    Murthi, A.; Menon, S.; Sednev, I.

    2011-12-01

    An inherent difficulty in the ability of global climate models to accurately simulate precipitation lies in the use of a large time step, Δt (usually 30 minutes), to solve the governing equations. Since microphysical processes are characterized by small time scales compared to Δt, finite difference approximations used to advance microphysics equations suffer from numerical instability and large time truncation errors. With this in mind, the sensitivity of precipitation simulated by the atmospheric component of CESM, namely the Community Atmosphere Model (CAM 5.1), to the microphysics time step (τ) is investigated. Model integrations are carried out for a period of five years with a spin up time of about six months for a horizontal resolution of 2.5 × 1.9 degrees and 30 levels in the vertical, with Δt = 1800 s. The control simulation with τ = 900 s is compared with one using τ = 300 s for accumulated precipitation and radi- ation budgets at the surface and top of the atmosphere (TOA), while keeping Δt fixed. Our choice of τ = 300 s is motivated by previous work on warm rain processes wherein it was shown that a value of τ around 300 s was necessary, but not sufficient, to ensure positive definiteness and numerical stability of the explicit time integration scheme used to integrate the microphysical equations. However, since the entire suite of microphysical processes are represented in our case, we suspect that this might impose additional restrictions on τ. The τ = 300 s case produces differences in large-scale accumulated rainfall from the τ = 900 s case by as large as 200 mm, over certain regions of the globe. The spatial patterns of total accumulated precipitation using τ = 300 s are in closer agreement with satellite observed precipitation, when compared to the τ = 900 s case. Differences are also seen in the radiation budget with the τ = 300 (900) s cases producing surpluses that range between 1-3 W/m2 at both the TOA and surface in the global

  11. Comparison of Fixed and Variable Time Step Trajectory Integration Methods for Cislunar Trajectories

    NASA Technical Reports Server (NTRS)

    Weeks, ichael W.; Thrasher, Stephen W.

    2007-01-01

    Due to the nonlinear nature of the Earth-Moon-Sun three-body problem and non-spherical gravity, CEV cislunar targeting algorithms will require many propagations in their search for a desired trajectory. For on-board targeting especially, the algorithm must have a simple, fast, and accurate propagator to calculate a trajectory with reasonable computation time, and still be robust enough to remain stable in the various flight regimes that the CEV will experience. This paper compares Cowell s method with a fourth-order Runge- Kutta integrator (RK4), Encke s method with a fourth-order Runge-Kutta- Nystr m integrator (RKN4), and a method known as Multi-Conic. Additionally, the study includes the Bond-Gottlieb 14-element method (BG14) and extends the investigation of Encke-Nystrom methods to integrators of higher order and with variable step size.

  12. Detection and Correction of Step Discontinuities in Kepler Flux Time Series

    NASA Technical Reports Server (NTRS)

    Kolodziejczak, J. J.; Morris, R. L.

    2011-01-01

    PDC 8.0 includes an implementation of a new algorithm to detect and correct step discontinuities appearing in roughly one of every 20 stellar light curves during a given quarter. The majority of such discontinuities are believed to result from high-energy particles (either cosmic or solar in origin) striking the photometer and causing permanent local changes (typically -0.5%) in quantum efficiency, though a partial exponential recovery is often observed [1]. Since these features, dubbed sudden pixel sensitivity dropouts (SPSDs), are uncorrelated across targets they cannot be properly accounted for by the current detrending algorithm. PDC detrending is based on the assumption that features in flux time series are due either to intrinsic stellar phenomena or to systematic errors and that systematics will exhibit measurable correlations across targets. SPSD events violate these assumptions and their successful removal not only rectifies the flux values of affected targets, but demonstrably improves the overall performance of PDC detrending [1].

  13. Effect of the processing steps on compositions of table olive since harvesting time to pasteurization.

    PubMed

    Nikzad, Nasim; Sahari, Mohammad A; Vanak, Zahra Piravi; Safafar, Hamed; Boland-nazar, Seyed A

    2013-08-01

    Weight, oil, fatty acids, tocopherol, polyphenol, and sterol properties of 5 olive cultivars (Zard, Fishomi, Ascolana, Amigdalolia, and Conservalia) during crude, lye treatment, washing, fermentation, and pasteurization steps were studied. Results showed: oil percent was higher and lower in Ascolana (crude step) and in Fishomi (pasteurization step), respectively; during processing steps, in all cultivars, oleic, palmitic, linoleic, and stearic acids were higher; the highest changes in saturated and unsaturated fatty acids were in fermentation step; the highest and the lowest ratios of ω3 / ω6 were in Ascolana (washing step) and in Zard (pasteurization step), respectively; the highest and the lowest tocopherol were in Amigdalolia and Fishomi, respectively, and major damage occurred in lye step; the highest and the lowest polyphenols were in Ascolana (crude step) and in Zard and Ascolana (pasteurization step), respectively; the major damage among cultivars occurred during lye step, in which the polyphenol reduced to 1/10 of first content; sterol did not undergo changes during steps. Reviewing of olive patents shows that many compositions of fruits such as oil quality, fatty acids, quantity and its fraction can be changed by alteration in cultivar and process.

  14. Security: Step by Step

    ERIC Educational Resources Information Center

    Svetcov, Eric

    2005-01-01

    This article provides a list of the essential steps to keeping a school's or district's network safe and sound. It describes how to establish a security architecture and approach that will continually evolve as the threat environment changes over time. The article discusses the methodology for implementing this approach and then discusses the…

  15. Introducing conjoint analysis method into delayed lotteries studies: its validity and time stability are higher than in adjusting

    PubMed Central

    Białek, Michał; Markiewicz, Łukasz; Sawicki, Przemysław

    2015-01-01

    The delayed lotteries are much more common in everyday life than are pure lotteries. Usually, we need to wait to find out the outcome of the risky decision (e.g., investing in a stock market, engaging in a relationship). However, most research has studied the time discounting and probability discounting in isolation using the methodologies designed specifically to track changes in one parameter. Most commonly used method is adjusting, but its reported validity and time stability in research on discounting are suboptimal. The goal of this study was to introduce the novel method for analyzing delayed lotteries—conjoint analysis—which hypothetically is more suitable for analyzing individual preferences in this area. A set of two studies compared the conjoint analysis with adjusting. The results suggest that individual parameters of discounting strength estimated with conjoint have higher predictive value (Study 1 and 2), and they are more stable over time (Study 2) compared to adjusting. We discuss these findings, despite the exploratory character of reported studies, by suggesting that future research on delayed lotteries should be cross-validated using both methods. PMID:25674069

  16. Children's sleep and adjustment over time: the role of socioeconomic context.

    PubMed

    El-Sheikh, Mona; Kelly, Ryan J; Buckhalt, Joseph A; Benjamin Hinnant, J

    2010-01-01

    Relations were examined between children's sleep and their externalizing and internalizing symptoms. Longitudinal relations were examined when children were in 3rd (T1) and 5th (T2) grades, and cross-sectional relations were assessed at T2. Participants included 176 children at T1 (M = 8.68 years) and 141 children at T2 (M = 10.70 years). Sleep was examined via subjective reports and actigraphy. Children reported on anxiety, self-esteem, and depression symptoms, and parents reported on children's externalizing and internalizing symptoms. Cross-sectionally and longitudinally, sleep problems were associated with worse adjustment outcomes; African American children or those from lower socioeconomic status homes were at particular risk. Findings highlight the importance of adequate sleep for children's optimal development, especially in the context of ecological risk.

  17. Associations of reallocating sitting time into standing or stepping with glucose, insulin and insulin sensitivity: a cross-sectional analysis of adults at risk of type 2 diabetes

    PubMed Central

    Edwardson, Charlotte L; Henson, Joe; Bodicoat, Danielle H; Bakrania, Kishan; Khunti, Kamlesh; Davies, Melanie J; Yates, Thomas

    2017-01-01

    Objective To quantify associations between sitting time and glucose, insulin and insulin sensitivity by considering reallocation of time into standing or stepping. Design Cross-sectional. Setting Leicestershire, UK, 2013. Participants Adults aged 30–75 years at high risk of impaired glucose regulation (IGR) or type 2 diabetes. 435 adults (age 66.8±7.4 years; 61.7% male; 89.2% white European) were included. Methods Participants wore an activPAL3 monitor 24 hours/day for 7 days to capture time spent sitting, standing and stepping. Fasting and 2-hour postchallenge glucose and insulin were assessed; insulin sensitivity was calculated by Homeostasis Model Assessment of Insulin Secretion (HOMA-IS) and Matsuda-Insulin Sensitivity Index (Matsuda-ISI). Isotemporal substitution regression modelling was used to quantify associations of substituting 30 min of waking sitting time (accumulated in prolonged (≥30 min) or short (<30 min) bouts) for standing or stepping on glucose regulation and insulin sensitivity. Interaction terms were fitted to assess whether the associations with measures of glucose regulation and insulin sensitivity was modified by sex or IGR status. Results After adjustment for confounders, including waist circumference, reallocation of prolonged sitting to short sitting time and to standing was associated with 4% lower fasting insulin and 4% higher HOMA-IS; reallocation of prolonged sitting to standing was also associated with a 5% higher Matsuda-ISI. Reallocation to stepping was associated with 5% lower 2-hour glucose, 7% lower fasting insulin, 13% lower 2-hour insulin and a 9% and 16% higher HOMA-IS and Matsuda-ISI, respectively. Reallocation of short sitting time to stepping was associated with 5% and 10% lower 2-hour glucose and 2-hour insulin and 12% higher Matsuda-ISI. Results were not modified by IGR status or sex. Conclusions Reallocating a small amount of short or prolonged sitting time with standing or stepping may improve 2-hour

  18. Outward Bound to the Galaxies--One Step at a Time

    ERIC Educational Resources Information Center

    Ward, R. Bruce; Miller-Friedmann, Jaimie; Sienkiewicz, Frank; Antonucci, Paul

    2012-01-01

    Less than a century ago, astronomers began to unlock the cosmic distances within and beyond the Milky Way. Understanding the size and scale of the universe is a continuing, step-by-step process that began with the remarkably accurate measurement of the distance to the Moon made by early Greeks. In part, the authors have ITEAMS (Innovative…

  19. Write a Research Paper One Step at a Time: Research Writing Guide.

    ERIC Educational Resources Information Center

    Evans, Helen, Ed.

    Intended to supplement the textbook series "Houghton Mifflin English Grammar and Composition" and to offer students and classroom teachers in the secondary schools a review of research writing, this guide outlines a step-by-step process allowing for thorough student comprehension and comfort with the application of basic research and…

  20. Seam-based variable-step Bresenham blending method for real-time video mosaicking

    NASA Astrophysics Data System (ADS)

    Zhang, Hongru; Shi, Zaifeng; Pang, Ke; Cao, Qingjie; Luo, Tao; Yao, Suying

    2016-09-01

    Image blending plays an important role in video mosaicking, which has a high demand for real-time performance and visual quality. This paper proposes a fast blending method based on Bresenham algorithm, which realizes blending by controlling the storing addresses of source pixels. The starting storing location is accurately computed based on the coordinates of the middle pixel of the seam instead of the first pixel's, reducing the accumulated error along the seam significantly. The other storing addresses are acquired using a variable-step Bresenham method, which takes advantage of burst mode operation of a dynamic memory and can achieve a good trade-off between the operation convenience and memory requirement. By the proposed method, complicated calculations of storing addresses are simplified into integer additions and subtractions, which is more suitable for hardware implementation. A hardware architecture based on field programmable gate array is presented to evaluate the proposed method with clock frequency analysis and resource assessment. The experimental results show that the proposed method achieves good performance of high image quality, low computational complexity, and low memory requirement.

  1. Multiple-Time Step Ab Initio Molecular Dynamics Based on Two-Electron Integral Screening.

    PubMed

    Fatehi, Shervin; Steele, Ryan P

    2015-03-10

    A multiple-timestep ab initio molecular dynamics scheme based on varying the two-electron integral screening method used in Hartree-Fock or density functional theory calculations is presented. Although screening is motivated by numerical considerations, it is also related to separations in the length- and timescales characterizing forces in a molecular system: Loose thresholds are sufficient to describe fast motions over short distances, while tight thresholds may be employed for larger length scales and longer times, leading to a practical acceleration of ab initio molecular dynamics simulations. Standard screening approaches can lead, however, to significant discontinuities in (and inconsistencies between) the energy and gradient when the screening threshold is loose, making them inappropriate for use in dynamics. To remedy this problem, a consistent window-screening method that smooths these discontinuities is devised. Further algorithmic improvements reuse electronic-structure information within the dynamics step and enhance efficiency relative to a naı̈ve multiple-timestepping protocol. The resulting scheme is shown to realize meaningful reductions in the cost of Hartree-Fock and B3LYP simulations of a moderately large system, the protonated sarcosine/glycine dipeptide embedded in a 19-water cluster.

  2. Local Discontinuous Galerkin Approximations And Variable Step Size, Variable Order Time Integration For Richards' Equation

    NASA Astrophysics Data System (ADS)

    Li, H.; Farthing, M. W.; Dawson, C. N.; Miller, C. T.

    2004-12-01

    Numerical simulation of Richards' equation continues to be difficult. It is highly nonlinear under common constitutive relations and exhibits sharp fronts in both the pressure head and volume fraction for many problems of interest. For a number of multiphase flow problems, the use of variable order and variable step size temporal discretizations has shown some advantages. However, the spatial discretizations commonly used for variably saturated flow are dominated by nonadaptive, low-order finite difference and finite element methods. Discontinuous Galerkin (DG) finite element methods have received significant attention in a number of fields for hyperbolic PDE's and, more recently, for elliptic and parabolic problems. DG approaches like the local discontinuous Galerkin (LDG) method are appealing for modeling subsurface flow since they can lead to velocity fields that are locally mass-conservative without the need for auxiliary variables or alternative meshes. DG discretizations are also inherently local and so better-suited for unstructured meshes and h-p adaption strategies than traditional methods. While some work has been done recently for multiphase subsurface flow, there are a range of issues related to the performance of DG methods for highly nonlinear parabolic problems like Richards' equation that have not been investigated fully. In this work, we consider the combination of higher order adaptive time integration with an LDG spatial discretization for Richards' equation. We compare this approach to standard low-order methods for a series of test problems and consider a number of issues including the methods' relative accuracy and computational efficiency.

  3. Time-of-Arrival Measurements of X-ray Emission Associated with Dart-Stepped Leader Steps in Natural and Rocket-and-Wire Triggered Lightning

    NASA Astrophysics Data System (ADS)

    Jordan, D. M.; Hill, J. D.; Uman, M. A.; Dwyer, J. R.; Rassoul, H. K.

    2012-12-01

    Time-of-arrival (TOA) techniques were used to determine the three-dimensional locations and emission times of x-ray and dE/dt sources measured at ground level in association with dart-stepped leader steps in natural and rocket-and-wire triggered lightning discharges recorded during summer 2011 at Camp Blanding, FL. The measurement network consisted of ten flat plate dE/dt antennas approximately co-located with eight plastic and two Lanthanum Bromide scintillation detectors arrayed around the launching facility over an area of about 0.25 square kilometers. For two triggered lightning dart-stepped leaders, x-ray sources were emitted from locations separated by average distances of 22.7 m and 29 m, respectively, from the locations of the associated dE/dt pulse peaks. The x-ray sources occurred beneath the dE/dt sources in 88% of the cases. X-rays were emitted from 20 ns to 2.16 μs following the dE/dt pulse peaks, with average temporal separations of 150 ns and 290 ns, respectively, for the two triggered lightning events. For one natural lightning dart-stepped leader, x-ray sources were emitted an average total distance of 39.2 m from the associated dE/dt pulse peak, and occurred beneath the location of the dE/dt source in 86% of the cases. The x-rays were emitted from 10 ns to 1.76 μs following the dE/dt pulse peak with an average temporal separation of 280 ns. In each of the three events, the altitude displacement between the dE/dt and x-ray sources dominated the total separation, accounting for 90%, 63%, and 72%, respectively, of the total separation. X-ray sources were distributed randomly in the lateral directions about the lightning channel in each event. For the triggered lightning events, x-rays were located from 2.5-83.5 μs prior to the return stroke at altitudes ranging from 24-336 m. For the natural lightning event, x-rays were located from 40.4-222.3 μs prior to the return stroke at altitudes ranging from 99-394 m. Cumulatively, 67% of the located x

  4. 31 CFR 501.737 - Adjustments of time, postponements and adjournments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... time, postponements and adjournments. (a) Availability. Except as otherwise provided by law, the Administrative Law Judge or the Secretary's designee, as appropriate, at any time prior to the filing of his or... place ordered, provided that, within the limits provided, the Administrative Law Judge or the...

  5. Stability of the high-order finite elements for acoustic or elastic wave propagation with high-order time stepping

    NASA Astrophysics Data System (ADS)

    De Basabe, Jonás D.; Sen, Mrinal K.

    2010-04-01

    We investigate the stability of some high-order finite element methods, namely the spectral element method and the interior-penalty discontinuous Galerkin method (IP-DGM), for acoustic or elastic wave propagation that have become increasingly popular in the recent past. We consider the Lax-Wendroff method (LWM) for time stepping and show that it allows for a larger time step than the classical leap-frog finite difference method, with higher-order accuracy. In particular the fourth-order LWM allows for a time step 73 per cent larger than that of the leap-frog method; the computational cost is approximately double per time step, but the larger time step partially compensates for this additional cost. Necessary, but not sufficient, stability conditions are given for the mentioned methods for orders up to 10 in space and time. The stability conditions for IP-DGM are approximately 20 and 60 per cent more restrictive than those for SEM in the acoustic and elastic cases, respectively.

  6. The Influence of Time Spent in Outdoor Play on Daily and Aerobic Step Count in Costa Rican Children

    ERIC Educational Resources Information Center

    Morera Castro, Maria del Rocio

    2011-01-01

    The purpose of this study is to examine the influence of time spent in outdoor play (i.e., on weekday and weekend days) on daily (i.e., average step count) and aerobic step count (i.e., average moderate to vigorous physical activity [MVPA] during the weekdays and weekend days) in fifth grade Costa Rican children. It was hypothesized that: (a)…

  7. Kinetic Analysis of Parallel-Consecutive First-Order Reactions with a Reversible Step: Concentration-Time Integrals Method

    ERIC Educational Resources Information Center

    Mucientes, A. E.; de la Pena, M. A.

    2009-01-01

    The concentration-time integrals method has been used to solve kinetic equations of parallel-consecutive first-order reactions with a reversible step. This method involves the determination of the area under the curve for the concentration of a given species against time. Computer techniques are used to integrate experimental curves and the method…

  8. Time-resolved spectral characterization of ring cavity surface emitting and ridge-type distributed feedback quantum cascade lasers by step-scan FT-IR spectroscopy.

    PubMed

    Brandstetter, Markus; Genner, Andreas; Schwarzer, Clemens; Mujagic, Elvis; Strasser, Gottfried; Lendl, Bernhard

    2014-02-10

    We present the time-resolved comparison of pulsed 2nd order ring cavity surface emitting (RCSE) quantum cascade lasers (QCLs) and pulsed 1st order ridge-type distributed feedback (DFB) QCLs using a step-scan Fourier transform infrared (FT-IR) spectrometer. Laser devices were part of QCL arrays and fabricated from the same laser material. Required grating periods were adjusted to account for the grating order. The step-scan technique provided a spectral resolution of 0.1 cm(-1) and a time resolution of 2 ns. As a result, it was possible to gain information about the tuning behavior and potential mode-hops of the investigated lasers. Different cavity-lengths were compared, including 0.9 mm and 3.2 mm long ridge-type and 0.97 mm (circumference) ring-type cavities. RCSE QCLs were found to have improved emission properties in terms of line-stability, tuning rate and maximum emission time compared to ridge-type lasers.

  9. A Step Response Based Mixed-Signal BIST Approach for Continuous-time Linear Circuits

    NASA Technical Reports Server (NTRS)

    Walker, Alvernon; Lala, P. K.

    2001-01-01

    A new Mixed-Signal Built-in self-test approach that is based upon the step response of a reconfigurable (or multifunction) analog block is presented in this paper. The technique requires the overlapping step response of the Circuit Under Test (CUT) for two circuit configurations. Each configuration can be realized by changing the topology of the CUT or by sampling two CUT nodes with differing step responses. The technique can effectively detect both soft and hard faults and does not require an analog-to-digital converter (ADC) and/or digital-to-analog converter(DAC). It also does not require any precision voltage sources or comparators. This approach does not require any additional analog circuits to realize the test signal generator and sample circuits. The paper is concluded with the application of the proposed approach to a circuit found in the work of Epstein et al and two ITC 97 analog benchmark circuits.

  10. Transient Crack Growth Behavior Under Cycle/Time-Dependent Step Loading for Pb-Containing and Pb-Free Solders

    NASA Astrophysics Data System (ADS)

    Fakpan, Kittichai; Otsuka, Yuichi; Miyashita, Yukio; Mutoh, Yoshiharu; Nagata, Kohsoku

    2013-12-01

    In the present study, fatigue crack growth tests of Pb-containing [Sn-37Pb (wt.%)] and Pb-free [Sn-3.0Ag-0.5Cu (wt.%)] solders were performed under cycle/time-dependent step loading at a constant J-integral range (Δ J). The C * parameter was also estimated for discussing time-dependent crack growth behavior. The experimental results indicated that acceleration of the crack growth rate at the beginning of the second loading step was induced when the C * value for the first loading step was high, regardless of time- or cycle-dependent crack growth and for both Sn-37Pb and Sn-3.0Ag-0.5Cu solders. The length of the acceleration region of the crack growth rate for both solders was in good agreement with the creep damage zone size estimated by the creep zone model proposed by Riedel and Rice.

  11. Parent adjustment over time in gay, lesbian, and heterosexual parent families adopting from foster care.

    PubMed

    Lavner, Justin A; Waterman, Jill; Peplau, Letitia Anne

    2014-01-01

    Although increasing numbers of gay and lesbian individuals and couples are adopting children, gay men and lesbian women continue to face increased scrutiny and legal obstacles from the child welfare system. To date, little research has compared the experiences of gay or lesbian and heterosexual adoptive parents over time, limiting conceptual understandings of the similarities they share and the unique challenges that gay and lesbian adoptive parents may face. This study compared the adoption satisfaction, depressive symptoms, parenting stress, and social support at 2, 12, and 24 months postplacement of 82 parents (60 heterosexual, 15 gay, 7 lesbian) adopting children from foster care in Los Angeles County. Few differences were found between heterosexual and gay or lesbian parents at any of the assessments or in their patterns of change over time. On average, parents in both household types reported significant increases in adoption satisfaction and maintained low, nonclinical levels of depressive symptoms and parenting stress over time. Across all family types, greater parenting stress was associated with more depressive symptoms and lower adoption satisfaction. Results indicated many similarities between gay or lesbian and heterosexual adoptive parents, and highlight a need for services to support adoptive parents throughout the transition to parenthood to promote their well-being. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  12. Characterization of Energy Conservation in Primary Knock-On Atom Cascades: Ballistic Phase Effects on Variable Time Steps

    SciTech Connect

    Corrales, Louis R.; Devanathan, Ram

    2006-09-01

    Non-equilibrium molecular dynamics simulation trajectories must in principle conserve energy along the entire path. Processes exist in high-energy primary knock-on atom cascades that can affect the energy conservation, specifically during the ballistic phase where collisions bring atoms into very close proximities. The solution, in general, is to reduce the time step size of the simulation. This work explores the effects of variable time step algorithms and the effects of specifying a maximum displacement. The period of the ballistic phase can be well characterized by methods developed in this work to monitor the kinetic energy dissipation during a high-energy cascade.

  13. Changing Step or Marking Time? Teacher Education Reforms for the Learning and Skills Sector in England

    ERIC Educational Resources Information Center

    Thompson, Ron; Robinson, Denise

    2008-01-01

    The unprecedented degree of attention given to the learning and skills sector in England by successive New Labour governments has led to a significant increase in what is expected of the teaching workforce. To help meet these expectations, a "step change" in the quality of initial teacher training for the sector is promised, alongside…

  14. New Parents' Psychological Adjustment and Trajectories of Early Parental Involvement.

    PubMed

    Jia, Rongfang; Kotila, Letitia E; Schoppe-Sullivan, Sarah J; Kamp Dush, Claire M

    2016-02-01

    Trajectories of parental involvement time (engagement and child care) across 3, 6, and 9 months postpartum and associations with parents' own and their partners' psychological adjustment (dysphoria, anxiety, and empathic personal distress) were examined using a sample of dual-earner couples experiencing first-time parenthood (N = 182 couples). Using time diary measures that captured intensive parenting moments, hierarchical linear modeling analyses revealed that patterns of associations between psychological adjustment and parental involvement time depended on the parenting domain, aspect of psychological adjustment, and parent gender. Psychological adjustment difficulties tended to bias the 2-parent system toward a gendered pattern of "mother step in" and "father step out," as father involvement tended to decrease, and mother involvement either remained unchanged or increased, in response to their own and their partners' psychological adjustment difficulties. In contrast, few significant effects were found in models using parental involvement to predict psychological adjustment.

  15. New Parents’ Psychological Adjustment and Trajectories of Early Parental Involvement

    PubMed Central

    Jia, Rongfang; Kotila, Letitia E.; Schoppe-Sullivan, Sarah J.; Kamp Dush, Claire M.

    2016-01-01

    Trajectories of parental involvement time (engagement and child care) across 3, 6, and 9 months postpartum and associations with parents’ own and their partners’ psychological adjustment (dysphoria, anxiety, and empathic personal distress) were examined using a sample of dual-earner couples experiencing first-time parenthood (N = 182 couples). Using time diary measures that captured intensive parenting moments, hierarchical linear modeling analyses revealed that patterns of associations between psychological adjustment and parental involvement time depended on the parenting domain, aspect of psychological adjustment, and parent gender. Psychological adjustment difficulties tended to bias the 2-parent system toward a gendered pattern of “mother step in” and “father step out,” as father involvement tended to decrease, and mother involvement either remained unchanged or increased, in response to their own and their partners’ psychological adjustment difficulties. In contrast, few significant effects were found in models using parental involvement to predict psychological adjustment. PMID:27397935

  16. BIOMAP A Daily Time Step, Mechanistic Model for the Study of Ecosystem Dynamics

    NASA Astrophysics Data System (ADS)

    Wells, J. R.; Neilson, R. P.; Drapek, R. J.; Pitts, B. S.

    2010-12-01

    of both climate and ecosystems must be done at coarse grid resolutions; smaller domains require higher resolution for the simulation of natural resource processes at the landscape scale and that of on-the-ground management practices. Via a combined multi-agency and private conservation effort we have implemented a Nested Scale Experiment (NeScE) that ranges from 1/2 degree resolution (global, ca. 50 km) to ca. 8km (North America) and 800 m (conterminous U.S.). Our first DGVM, MC1, has been implemented at all 3 scales. We are just beginning to implement BIOMAP into NeScE, with its unique features, and daily time step, as a counterpoint to MC1. We believe it will be more accurate at all resolutions providing better simulations of vegetation distribution, carbon balance, runoff, fire regimes and drought impacts.

  17. The effect of timing electrical stimulation to robotic-assisted stepping on neuromuscular activity and associated kinematics.

    PubMed

    Askari, Sina; Chao, TeKang; de Leon, Ray D; Won, Deborah S

    2013-01-01

    Results of previous studies raise the question of how timing neuromuscular functional electrical stimulation (FES) to limb movements during stepping might alter neuromuscular control differently than patterned stimulation alone. We have developed a prototype FES system for a rodent model of spinal cord injury (SCI) that times FES to robotic treadmill training (RTT). In this study, one group of rats (n = 6) was trained with our FES+RTT system and received stimulation of the ankle flexor (tibialis anterior [TA]) muscle timed according to robot-controlled hind-limb position (FES+RTT group); a second group (n = 5) received a similarly patterned stimulation, randomly timed with respect to the rats' hind-limb movements, while they were in their cages (randomly timed stimulation [RS] group). After 4 wk of training, we tested treadmill stepping ability and compared kinematic measures of hind-limb movement and electromyography (EMG) activity in the TA. The FES+RTT group stepped faster and exhibited TA EMG profiles that better matched the applied stimulation profile during training than the RS group. The shape of the EMG profile was assessed by "gamma," a measure that quantified the concentration of EMG activity during the early swing phase of the gait cycle. This gamma measure was 112% higher for the FES+RTT group than for the RS group. The FES+RTT group exhibited burst-to-step latencies that were 41% shorter and correspondingly exhibited a greater tendency to perform ankle flexion movements during stepping than the RS group, as measured by the percentage of time the hind limb was either dragging or in withdrawal. The results from this study support the hypothesis that locomotor training consisting of FES timed to hind-limb movement improves the activation of hind-limb muscle more so than RS alone. Our rodent FES+RTT system can serve as a tool to help further develop this combined therapy to target appropriate neurophysiological changes for locomotor control.

  18. Adjustment to Subtle Time Constraints and Power Law Learning in Rapid Serial Visual Presentation.

    PubMed

    Shin, Jacqueline C; Chang, Seah; Cho, Yang Seok

    2015-01-01

    We investigated whether attention could be modulated through the implicit learning of temporal information in a rapid serial visual presentation (RSVP) task. Participants identified two target letters among numeral distractors. The stimulus-onset asynchrony immediately following the first target (SOA1) varied at three levels (70, 98, and 126 ms) randomly between trials or fixed within blocks of trials. Practice over 3 consecutive days resulted in a continuous improvement in the identification rate for both targets and attenuation of the attentional blink (AB), a decrement in target (T2) identification when presented 200-400 ms after another target (T1). Blocked SOA1s led to a faster rate of improvement in RSVP performance and more target order reversals relative to random SOA1s, suggesting that the implicit learning of SOA1 positively affected performance. The results also reveal "power law" learning curves for individual target identification as well as the reduction in the AB decrement. These learning curves reflect the spontaneous emergence of skill through subtle attentional modulations rather than general attentional distribution. Together, the results indicate that implicit temporal learning could improve high level and rapid cognitive processing and highlights the sensitivity and adaptability of the attentional system to subtle constraints in stimulus timing.

  19. Throughput increase by adjustment of the BARC drying time with coat track process

    NASA Astrophysics Data System (ADS)

    Brakensiek, Nickolas L.; Long, Ryan

    2005-05-01

    Throughput of a coater module within the coater track is related to the solvent evaporation rate from the material that is being coated. Evaporation rate is controlled by the spin dynamics of the wafer and airflow dynamics over the wafer. Balancing these effects is the key to achieving very uniform coatings across a flat unpatterned wafer. As today"s coat tracks are being pushed to higher throughputs to match the scanner, the coat module throughput must be increased as well. For chemical manufacturers the evaporation rate of the material depends on the solvent used. One measure of relative evaporation rates is to compare flash points of a solvent. The lower the flash point, the quicker the solvent will evaporate. It is possible to formulate products with these volatile solvents although at a price. Shipping and manufacturing a more flammable product increase chances of fire, thereby increasing insurance premiums. Also, the end user of these chemicals will have to take extra precautions in the fab and in storage of these more flammable chemicals. An alternative coat process is possible which would allow higher throughput in a distinct coat module without sacrificing safety. A tradeoff is required for this process, that being a more complicated coat process and a higher viscosity chemical. The coat process uses the fact that evaporation rate depends on the spin dynamics of the wafer by utilizing a series of spin speeds that first would set the thickness of the material followed by a high spin speed to remove the residual solvent. This new process can yield a throughput of over 150 wafers per hour (wph) given two coat modules. The thickness uniformity of less than 2 nm (3 sigma) is still excellent, while drying times are shorter than 10 seconds to achieve the 150 wph throughput targets.

  20. Adaptice-step time integration package for stiff, nonstiff and multi-rate systems of ordinary differential equations (ODEs)

    SciTech Connect

    2014-06-01

    ARKode is part of a software family called SUNDIALS: SUite of Nonlinear and Differential/ALgebraic equation Solvers [1]. The ARKode solver library provides an adaptive-step time integration package for stiff, nonstiff and multi-rate systems of ordinary differential equations (ODEs) using Runge Kutta methods [2].

  1. A stabilized Runge-Kutta-Legendre method for explicit super-time-stepping of parabolic and mixed equations

    NASA Astrophysics Data System (ADS)

    Meyer, Chad D.; Balsara, Dinshaw S.; Aslam, Tariq D.

    2014-01-01

    Parabolic partial differential equations appear in several physical problems, including problems that have a dominant hyperbolic part coupled to a sub-dominant parabolic component. Explicit methods for their solution are easy to implement but have very restrictive time step constraints. Implicit solution methods can be unconditionally stable but have the disadvantage of being computationally costly or difficult to implement. Super-time-stepping methods for treating parabolic terms in mixed type partial differential equations occupy an intermediate position. In such methods each superstep takes “s” explicit Runge-Kutta-like time-steps to advance the parabolic terms by a time-step that is s2 times larger than a single explicit time-step. The expanded stability is usually obtained by mapping the short recursion relation of the explicit Runge-Kutta scheme to the recursion relation of some well-known, stable polynomial. Prior work has built temporally first- and second-order accurate super-time-stepping methods around the recursion relation associated with Chebyshev polynomials. Since their stability is based on the boundedness of the Chebyshev polynomials, these methods have been called RKC1 and RKC2. In this work we build temporally first- and second-order accurate super-time-stepping methods around the recursion relation associated with Legendre polynomials. We call these methods RKL1 and RKL2. The RKL1 method is first-order accurate in time; the RKL2 method is second-order accurate in time. We verify that the newly-designed RKL1 and RKL2 schemes have a very desirable monotonicity preserving property for one-dimensional problems - a solution that is monotone at the beginning of a time step retains that property at the end of that time step. It is shown that RKL1 and RKL2 methods are stable for all values of the diffusion coefficient up to the maximum value. We call this a convex monotonicity preserving property and show by examples that it is very useful in

  2. A stabilized Runge–Kutta–Legendre method for explicit super-time-stepping of parabolic and mixed equations

    SciTech Connect

    Meyer, Chad D.; Balsara, Dinshaw S.; Aslam, Tariq D.

    2014-01-15

    Parabolic partial differential equations appear in several physical problems, including problems that have a dominant hyperbolic part coupled to a sub-dominant parabolic component. Explicit methods for their solution are easy to implement but have very restrictive time step constraints. Implicit solution methods can be unconditionally stable but have the disadvantage of being computationally costly or difficult to implement. Super-time-stepping methods for treating parabolic terms in mixed type partial differential equations occupy an intermediate position. In such methods each superstep takes “s” explicit Runge–Kutta-like time-steps to advance the parabolic terms by a time-step that is s{sup 2} times larger than a single explicit time-step. The expanded stability is usually obtained by mapping the short recursion relation of the explicit Runge–Kutta scheme to the recursion relation of some well-known, stable polynomial. Prior work has built temporally first- and second-order accurate super-time-stepping methods around the recursion relation associated with Chebyshev polynomials. Since their stability is based on the boundedness of the Chebyshev polynomials, these methods have been called RKC1 and RKC2. In this work we build temporally first- and second-order accurate super-time-stepping methods around the recursion relation associated with Legendre polynomials. We call these methods RKL1 and RKL2. The RKL1 method is first-order accurate in time; the RKL2 method is second-order accurate in time. We verify that the newly-designed RKL1 and RKL2 schemes have a very desirable monotonicity preserving property for one-dimensional problems – a solution that is monotone at the beginning of a time step retains that property at the end of that time step. It is shown that RKL1 and RKL2 methods are stable for all values of the diffusion coefficient up to the maximum value. We call this a convex monotonicity preserving property and show by examples that it is very

  3. Real-time, step-wise, electrical detection of protein molecules using dielectrophoretically aligned SWNT-film FET aptasensors.

    PubMed

    An, Taechang; Kim, Ki Su; Hahn, Sei Kwang; Lim, Geunbae

    2010-08-21

    Aptamer functionalized addressable SWNT-film arrays between cantilever electrodes were successfully developed for biosensor applications. Dielectrophoretically aligned SWNT suspended films made possible highly specific and rapid detection of target proteins with a large binding surface area. Thrombin aptamer immobilized SWNT-film FET biosensor resulted in a real-time, label-free, and electrical detection of thrombin molecules down to a concentration of ca. 7 pM with a step-wise rapid response time of several seconds.

  4. Development of a time-dependent incompressible Navier-Stokes solver based on a fractional-step method

    NASA Technical Reports Server (NTRS)

    Rosenfeld, Moshe

    1990-01-01

    The development, validation and application of a fractional step solution method of the time-dependent incompressible Navier-Stokes equations in generalized coordinate systems are discussed. A solution method that combines a finite-volume discretization with a novel choice of the dependent variables and a fractional step splitting to obtain accurate solutions in arbitrary geometries was previously developed for fixed-grids. In the present research effort, this solution method is extended to include more general situations, including cases with moving grids. The numerical techniques are enhanced to gain efficiency and generality.

  5. Issues in measure-preserving three dimensional flow integrators: Self-adjointness, reversibility, and non-uniform time stepping

    SciTech Connect

    Finn, John M.

    2015-03-01

    Properties of integration schemes for solenoidal fields in three dimensions are studied, with a focus on integrating magnetic field lines in a plasma using adaptive time stepping. It is shown that implicit midpoint (IM) and a scheme we call three-dimensional leapfrog (LF) can do a good job (in the sense of preserving KAM tori) of integrating fields that are reversible, or (for LF) have a 'special divergence-free' property. We review the notion of a self-adjoint scheme, showing that such schemes are at least second order accurate and can always be formed by composing an arbitrary scheme with its adjoint. We also review the concept of reversibility, showing that a reversible but not exactly volume-preserving scheme can lead to a fractal invariant measure in a chaotic region, although this property may not often be observable. We also show numerical results indicating that the IM and LF schemes can fail to preserve KAM tori when the reversibility property (and the SDF property for LF) of the field is broken. We discuss extensions to measure preserving flows, the integration of magnetic field lines in a plasma and the integration of rays for several plasma waves. The main new result of this paper relates to non-uniform time stepping for volume-preserving flows. We investigate two potential schemes, both based on the general method of Ref. [11], in which the flow is integrated in split time steps, each Hamiltonian in two dimensions. The first scheme is an extension of the method of extended phase space, a well-proven method of symplectic integration with non-uniform time steps. This method is found not to work, and an explanation is given. The second method investigated is a method based on transformation to canonical variables for the two split-step Hamiltonian systems. This method, which is related to the method of non-canonical generating functions of Ref. [35], appears to work very well.

  6. Vigilance and Activity Time-Budget Adjustments of Wintering Hooded Cranes, Grus monacha, in Human-Dominated Foraging Habitats

    PubMed Central

    Li, Chunlin; Zhou, Lizhi; Xu, Li; Zhao, Niannian; Beauchamp, Guy

    2015-01-01

    Due to loss and degradation of natural wetlands, waterbirds increasingly rely on surrounding human-dominated habitats to obtain food. Quantifying vigilance patterns, investigating the trade-off among various activities, and examining the underlying mechanisms will help us understand how waterbirds adapt to human-caused disturbances. During two successive winters (November-February of 2012–13 and 2013–14), we studied the hooded crane, Grus monacha, in the Shengjin Lake National Nature Reserve (NNR), China, to investigate how the species responds to human disturbances through vigilance and activity time-budget adjustments. Our results showed striking differences in the behavior of the cranes when foraging in the highly disturbed rice paddy fields found in the buffer zone compared with the degraded natural wetlands in the core area of the NNR. Time spent vigilant decreased with flock size and cranes spent more time vigilant in the human-dominated buffer zone. In the rice paddy fields, the birds were more vigilant but also fed more at the expense of locomotion and maintenance activities. Adult cranes spent more time vigilant and foraged less than juveniles. We recommend habitat recovery in natural wetlands and community co-management in the surrounding human-dominated landscape for conservation of the hooded crane and, generally, for the vast numbers of migratory waterbirds wintering in the middle and lower reaches of the Yangtze River floodplain. PMID:25768111

  7. Integrating Rapid Diagnostics and Antimicrobial Stewardship in Two Community Hospitals Improved Process Measures and Antibiotic Adjustment Time.

    PubMed

    Lockwood, Ashley M; Perez, Katherine K; Musick, William L; Ikwuagwu, Judy O; Attia, Engie; Fasoranti, Oyejoke O; Cernoch, Patricia L; Olsen, Randall J; Musser, James M

    2016-04-01

    OBJECTIVE To assess the impact of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry for rapid pathogen identification directly from early-positive blood cultures coupled with an antimicrobial stewardship program (ASP) in two community hospitals. Process measures and outcomes prior and after implementation of MALDI-TOF/ASP were evaluated. DESIGN Multicenter retrospective study. SETTING Two community hospitals in a system setting, Houston Methodist (HM) Sugar Land Hospital (235 beds) or HM Willowbrook Hospital (241 beds). PATIENTS Patients ≥ 18 years of age with culture-proven Gram-negative bacteremia. INTERVENTION Blood cultures from both hospitals were sent to and processed at our central microbiology laboratory. Clinical pharmacists at respective hospitals were notified of pathogen ID and susceptibility results. RESULTS We evaluated 572 patients for possible inclusion. After pre-defined exclusion criteria, 151 patients were included in the pre-intervention group and 242 were included in the intervention group. After MALDI-TOF/ASP implementation, the mean identification time after culture positivity was significantly reduced from 32 hours (±16 hours) to 6.5 hours (±5.4 hours) (P<.001); mean time to susceptibility results was significantly reduced from 48 (±22) hours to 23 (±14) hours (P<.001); and time to therapy adjustment was significantly reduced from 75 (±59) hours to 30 (±30) hours (P<.001). Mean hospital costs per patient were $3,411 less in the intervention group compared with the pre-intervention group ($18,645 vs $15,234; P=.04). CONCLUSION This study is the first to analyze the impact of MALDI-TOF coupled with an ASP in a community hospital setting. Time to results significantly differed with the use of MALDI-TOF, and time to appropriate therapy was significantly improved with the addition of ASP.

  8. PHOEBE - step by step manual

    NASA Astrophysics Data System (ADS)

    Zasche, P.

    2016-03-01

    An easy step-by-step manual of PHOEBE is presented. It should serve as a starting point for the first time users of PHOEBE analyzing the eclipsing binary light curve. It is demonstrated on one particular detached system also with the downloadable data and the whole procedure is described easily till the final trustworthy fit is being reached.

  9. Timing matters: tuning the mechanics of a muscle-tendon unit by adjusting stimulation phase during cyclic contractions.

    PubMed

    Sawicki, Gregory S; Robertson, Benjamin D; Azizi, Emanuel; Roberts, Thomas J

    2015-10-01

    A growing body of research on the mechanics and energetics of terrestrial locomotion has demonstrated that elastic elements acting in series with contracting muscle are critical components of sustained, stable and efficient gait. Far fewer studies have examined how the nervous system modulates muscle-tendon interaction dynamics to optimize 'tuning' or meet varying locomotor demands. To explore the fundamental neuromechanical rules that govern the interactions between series elastic elements (SEEs) and contractile elements (CEs) within a compliant muscle-tendon unit (MTU), we used a novel work loop approach that included implanted sonomicrometry crystals along muscle fascicles. This enabled us to decouple CE and SEE length trajectories when cyclic strain patterns were applied to an isolated plantaris MTU from the bullfrog (Lithobates catesbeianus). Using this approach, we demonstrate that the onset timing of muscle stimulation (i.e. stimulation phase) that involves a symmetrical MTU stretch-shorten cycle during active force production results in net zero mechanical power output, and maximal decoupling of CE and MTU length trajectories. We found it difficult to 'tune' the muscle-tendon system for strut-like isometric force production by adjusting stimulation phase only, as the zero power output condition involved significant positive and negative mechanical work by the CE. A simple neural mechanism - adjusting muscle stimulation phase - could shift an MTU from performing net zero to net positive (energy producing) or net negative (energy absorbing) mechanical work under conditions of changing locomotor demand. Finally, we show that modifications to the classical work loop paradigm better represent in vivo muscle-tendon function during locomotion.

  10. Timing matters: tuning the mechanics of a muscle–tendon unit by adjusting stimulation phase during cyclic contractions

    PubMed Central

    Sawicki, Gregory S.; Robertson, Benjamin D.; Azizi, Emanuel; Roberts, Thomas J.

    2015-01-01

    ABSTRACT A growing body of research on the mechanics and energetics of terrestrial locomotion has demonstrated that elastic elements acting in series with contracting muscle are critical components of sustained, stable and efficient gait. Far fewer studies have examined how the nervous system modulates muscle–tendon interaction dynamics to optimize ‘tuning’ or meet varying locomotor demands. To explore the fundamental neuromechanical rules that govern the interactions between series elastic elements (SEEs) and contractile elements (CEs) within a compliant muscle–tendon unit (MTU), we used a novel work loop approach that included implanted sonomicrometry crystals along muscle fascicles. This enabled us to decouple CE and SEE length trajectories when cyclic strain patterns were applied to an isolated plantaris MTU from the bullfrog (Lithobates catesbeianus). Using this approach, we demonstrate that the onset timing of muscle stimulation (i.e. stimulation phase) that involves a symmetrical MTU stretch–shorten cycle during active force production results in net zero mechanical power output, and maximal decoupling of CE and MTU length trajectories. We found it difficult to ‘tune’ the muscle–tendon system for strut-like isometric force production by adjusting stimulation phase only, as the zero power output condition involved significant positive and negative mechanical work by the CE. A simple neural mechanism – adjusting muscle stimulation phase – could shift an MTU from performing net zero to net positive (energy producing) or net negative (energy absorbing) mechanical work under conditions of changing locomotor demand. Finally, we show that modifications to the classical work loop paradigm better represent in vivo muscle–tendon function during locomotion. PMID:26232413

  11. Convergence of a class of semi-implicit time-stepping schemes for nonsmooth rigid multibody dynamics.

    SciTech Connect

    Gavrea, B. I.; Anitescu, M.; Potra, F. A.; Mathematics and Computer Science; Univ. of Pennsylvania; Univ. of Maryland

    2008-01-01

    In this work we present a framework for the convergence analysis in a measure differential inclusion sense of a class of time-stepping schemes for multibody dynamics with contacts, joints, and friction. This class of methods solves one linear complementarity problem per step and contains the semi-implicit Euler method, as well as trapezoidal-like methods for which second-order convergence was recently proved under certain conditions. By using the concept of a reduced friction cone, the analysis includes, for the first time, a convergence result for the case that includes joints. An unexpected intermediary result is that we are able to define a discrete velocity function of bounded variation, although the natural discrete velocity function produced by our algorithm may have unbounded variation.

  12. Convergence of a Time-Stepping Scheme for Rigid-Body Dynamics and Resolution of Painlevé's Problem

    NASA Astrophysics Data System (ADS)

    Stewart, David E.

    This paper gives convergence theory for a new implicit time-stepping scheme for general rigid-body dynamics with Coulomb friction and purely inelastic collisions and shocks. An important consequence of this work is the proof of existence of solutions of rigid-body problems which include the famous counterexamples of Painlevé. The mathematical basis for this work is the formulation of the rigid-body problem in terms of measure differential inclusions of Moreau and Monteiro Marques. The implicit time-stepping method is based on complementarity problems, and is essentially a particular case of the algorithm described in Anitescu & Potra [2], which in turn is based on the formulation in Stewart & Trinkle [47].

  13. Review of RT-LAB and Steps Involved for Implementation of a Simulink Model from MATLAB to REAL-TIME

    NASA Astrophysics Data System (ADS)

    Mikkili, Suresh; Panda, Anup Kumar

    2013-11-01

    In recent days, every researcher wants to develop his/her model in real-time. Simulation tools have been widely used for the design and improvement of electrical systems since the mid-twentieth century. The evolution of simulation tools has progressed in step with the evolution of computing technologies. Now a days, computing technologies have improved dramatically in performance and become widely available at a steadily decreasing cost. Consequently, simulation tools have also seen dramatic performance gains and steady cost decreases. Researchers and engineers now have access to affordable, high-performance simulation tools that were previously too cost prohibitive, except for the largest manufacturers and utilities.This article has introduced a specific class of digital simulator known as a real-time simulator by answering the questions "What is real-time simulation?" "Why is it needed" and "How it works". The latest trend in real-time simulation consists of exporting simulation models to FPGA. In this article, the steps involved for implementation of a model from MATLAB to REAL-TIME are provided in detail. The detailed real-time results are presented to support the feasibility of real-time digital simulator.

  14. High resolution frequency to time domain transformations applied to the stepped carrier MRIS measurements

    NASA Technical Reports Server (NTRS)

    Ardalan, Sasan H.

    1992-01-01

    Two narrow-band radar systems are developed for high resolution target range estimation in inhomogeneous media. They are reformulations of two presently existing systems such that high resolution target range estimates may be achieved despite the use of narrow bandwidth radar pulses. A double sideband suppressed carrier radar technique originally derived in 1962, and later abandoned due to its inability to accurately measure target range in the presence of an interfering reflection, is rederived to incorporate the presence of an interfering reflection. The new derivation shows that the interfering reflection causes a period perturbation in the measured phase response. A high resolution spectral estimation technique is used to extract the period of this perturbation leading to accurate target range estimates independent of the signal-to-interference ratio. A non-linear optimal signal processing algorithm is derived for a frequency-stepped continuous wave radar system. The resolution enhancement offered by optimal signal processing of the data over the conventional Fourier Transform technique is clearly demonstrated using measured radar data. A method for modeling plane wave propagation in inhomogeneous media based on transmission line theory is derived and studied. Several simulation results including measurement of non-uniform electron plasma densities that develop near the heat tiles of a space re-entry vehicle are presented which verify the validity of the model.

  15. Time-stepping stability of continuous and discontinuous finite-element methods for 3-D wave propagation

    NASA Astrophysics Data System (ADS)

    Mulder, W. A.; Zhebel, E.; Minisini, S.

    2014-02-01

    We analyse the time-stepping stability for the 3-D acoustic wave equation, discretized on tetrahedral meshes. Two types of methods are considered: mass-lumped continuous finite elements and the symmetric interior-penalty discontinuous Galerkin method. Combining the spatial discretization with the leap-frog time-stepping scheme, which is second-order accurate and conditionally stable, leads to a fully explicit scheme. We provide estimates of its stability limit for simple cases, namely, the reference element with Neumann boundary conditions, its distorted version of arbitrary shape, the unit cube that can be partitioned into six tetrahedra with periodic boundary conditions and its distortions. The Courant-Friedrichs-Lewy stability limit contains an element diameter for which we considered different options. The one based on the sum of the eigenvalues of the spatial operator for the first-degree mass-lumped element gives the best results. It resembles the diameter of the inscribed sphere but is slightly easier to compute. The stability estimates show that the mass-lumped continuous and the discontinuous Galerkin finite elements of degree 2 have comparable stability conditions, whereas the mass-lumped elements of degree one and three allow for larger time steps.

  16. Finite time step and spatial grid effects in δf simulation of warm plasmas

    SciTech Connect

    Sturdevant, Benjamin J.; Parker, Scott E.

    2016-01-15

    This paper introduces a technique for analyzing time integration methods used with the particle weight equations in δf method particle-in-cell (PIC) schemes. The analysis applies to the simulation of warm, uniform, periodic or infinite plasmas in the linear regime and considers the collective behavior similar to the analysis performed by Langdon for full-f PIC schemes [1,2]. We perform both a time integration analysis and spatial grid analysis for a kinetic ion, adiabatic electron model of ion acoustic waves. An implicit time integration scheme is studied in detail for δf simulations using our weight equation analysis and for full-f simulations using the method of Langdon. It is found that the δf method exhibits a CFL-like stability condition for low temperature ions, which is independent of the parameter characterizing the implicitness of the scheme. The accuracy of the real frequency and damping rate due to the discrete time and spatial schemes is also derived using a perturbative method. The theoretical analysis of numerical error presented here may be useful for the verification of simulations and for providing intuition for the design of new implicit time integration schemes for the δf method, as well as understanding differences between δf and full-f approaches to plasma simulation.

  17. Finite time step and spatial grid effects in δf simulation of warm plasmas

    NASA Astrophysics Data System (ADS)

    Sturdevant, Benjamin J.; Parker, Scott E.

    2016-01-01

    This paper introduces a technique for analyzing time integration methods used with the particle weight equations in δf method particle-in-cell (PIC) schemes. The analysis applies to the simulation of warm, uniform, periodic or infinite plasmas in the linear regime and considers the collective behavior similar to the analysis performed by Langdon for full-f PIC schemes [1,2]. We perform both a time integration analysis and spatial grid analysis for a kinetic ion, adiabatic electron model of ion acoustic waves. An implicit time integration scheme is studied in detail for δf simulations using our weight equation analysis and for full-f simulations using the method of Langdon. It is found that the δf method exhibits a CFL-like stability condition for low temperature ions, which is independent of the parameter characterizing the implicitness of the scheme. The accuracy of the real frequency and damping rate due to the discrete time and spatial schemes is also derived using a perturbative method. The theoretical analysis of numerical error presented here may be useful for the verification of simulations and for providing intuition for the design of new implicit time integration schemes for the δf method, as well as understanding differences between δf and full-f approaches to plasma simulation.

  18. Pseudo-real-time low-pass filter in ECG, self-adjustable to the frequency spectra of the waves.

    PubMed

    Christov, Ivaylo; Neycheva, Tatyana; Schmid, Ramun; Stoyanov, Todor; Abächerli, Roger

    2017-02-04

    The electrocardiogram (ECG) acquisition is often accompanied by high-frequency electromyographic (EMG) noise. The noise is difficult to be filtered, due to considerable overlapping of its frequency spectrum to the frequency spectrum of the ECG. Today, filters must conform to the new guidelines (2007) for low-pass filtering in ECG with cutoffs of 150 Hz for adolescents and adults, and to 250 Hz for children. We are suggesting a pseudo-real-time low-pass filter, self-adjustable to the frequency spectra of the ECG waves. The filter is based on the approximation procedure of Savitzky-Golay with dynamic change in the cutoff frequency. The filter is implemented pseudo-real-time (real-time with a certain delay). An additional option is the automatic on/off triggering, depending on the presence/absence of EMG noise. The analysis of the proposed filter shows that the low-frequency components of the ECG (low-power P- and T-waves, PQ-, ST- and TP-segments) are filtered with a cutoff of 14 Hz, the high-power P- and T-waves are filtered with a cutoff frequency in the range of 20-30 Hz, and the high-frequency QRS complexes are filtered with cutoff frequency of higher than 100 Hz. The suggested dynamic filter satisfies the conflicting requirements for a strong suppression of EMG noise and at the same time a maximal preservation of the ECG high-frequency components.

  19. Parallel machine scheduling with step-deteriorating jobs and setup times by a hybrid discrete cuckoo search algorithm

    NASA Astrophysics Data System (ADS)

    Guo, Peng; Cheng, Wenming; Wang, Yi

    2015-11-01

    This article considers the parallel machine scheduling problem with step-deteriorating jobs and sequence-dependent setup times. The objective is to minimize the total tardiness by determining the allocation and sequence of jobs on identical parallel machines. In this problem, the processing time of each job is a step function dependent upon its starting time. An individual extended time is penalized when the starting time of a job is later than a specific deterioration date. The possibility of deterioration of a job makes the parallel machine scheduling problem more challenging than ordinary ones. A mixed integer programming model for the optimal solution is derived. Due to its NP-hard nature, a hybrid discrete cuckoo search algorithm is proposed to solve this problem. In order to generate a good initial swarm, a modified Biskup-Hermann-Gupta (BHG) heuristic called MBHG is incorporated into the population initialization. Several discrete operators are proposed in the random walk of Lévy flights and the crossover search. Moreover, a local search procedure based on variable neighbourhood descent is integrated into the algorithm as a hybrid strategy in order to improve the quality of elite solutions. Computational experiments are executed on two sets of randomly generated test instances. The results show that the proposed hybrid algorithm can yield better solutions in comparison with the commercial solver CPLEX® with a one hour time limit, the discrete cuckoo search algorithm and the existing variable neighbourhood search algorithm.

  20. Numerical simulation of diffusion MRI signals using an adaptive time-stepping method

    NASA Astrophysics Data System (ADS)

    Li, Jing-Rebecca; Calhoun, Donna; Poupon, Cyril; Le Bihan, Denis

    2014-01-01

    The effect on the MRI signal of water diffusion in biological tissues in the presence of applied magnetic field gradient pulses can be modelled by a multiple compartment Bloch-Torrey partial differential equation. We present a method for the numerical solution of this equation by coupling a standard Cartesian spatial discretization with an adaptive time discretization. The time discretization is done using the explicit Runge-Kutta-Chebyshev method, which is more efficient than the forward Euler time discretization for diffusive-type problems. We use this approach to simulate the diffusion MRI signal from the extra-cylindrical compartment in a tissue model of the brain gray matter consisting of cylindrical and spherical cells and illustrate the effect of cell membrane permeability.

  1. Improvements to Stepped Frequency Microwave Radiometer Real-time Tropical Cyclone Products

    NASA Astrophysics Data System (ADS)

    Uhlhorn, E. W.; Klotz, B.

    2012-12-01

    With the installation of C-band stepped frequency microwave radiometers (SFMR) on Air Force Reserve Command WC-130J hurricane reconnaissance aircraft, the SFMR has assumed a prominent role for operational measurement of surface winds, and thus, hurricane intensity estimation. The current SFMR wind retrieval algorithm was developed from GPS dropwindsonde surface wind measurements, and has been successfully implemented across all SFMR-equipped aircraft. The algorithm improvements were specifically targeted at improving surface wind accuracy at hurricane force conditions (> 65 kts, 33 m/s), especially within the eyewall, although the SFMR surface wind vs. emissivity geophysical model function was developed over a broad range of wind speeds (10-140 kts, 5-70 m/s) with the expectation that the hurricane wind field could be readily measured in general. Due to the significant microwave absorption by precipitation, a by-product of the wind retrieval process is an estimate of the path-averaged rain rate (in actuality, the rain water content). An SFMR surface wind speed high bias in strong precipitation has recently been quantified and is particularly evident at weak-to-moderate wind speeds (<65 kts, 33 m/s) and large rain rates (>20 mm/hr), which has important implications for identifying tropical systems at the depression and storm stages, and additionally for observing significant outer wind radii. A major reason for this wind bias is due to an inaccurate rain absorption model that was used to develop the current surface emissivity vs. wind speed geophysical model function. Observations now suggest that the rain-induced absorption is significantly overestimated by the model, resulting in underestimated rain rate values. With the wind speed bias identified, the rain absorption component of the SFMR geophysical model function is addressed to provide an improved rain rate product. This new absorption model is developed by relating SFMR excess brightness temperature

  2. An expert system for setting time steps in dynamic finite element programs

    NASA Technical Reports Server (NTRS)

    Ramirez, Martin R.; Belytschko, Ted

    1989-01-01

    An expert system, ETUDES - Expert Time integration control Using Deep and Surface Knowledge System, which addresses the determination of the timestep for time integration of linear structural dynamic equations is described. This timestep may also be applicable for a moderately nonlinear simulation of the same structure. The program also determines whether an explicit or implicit method is most efficient for the particular simulation. A production rule programming system written in OPS5 is used for the implementation of this prototype expert system. Issues relating to the expert system architecture for this application, such as knowledge representation and structure, as well as domain knowledge are discussed. The prototype is evaluated by measuring its performance in various benchmark model problems.

  3. Effect of moisture and drying time on the bond strength of the one-step self-etching adhesive system

    PubMed Central

    Lee, Yoon

    2012-01-01

    Objectives To investigate the effect of dentin moisture degree and air-drying time on dentin-bond strength of two different one-step self-etching adhesive systems. Materials and Methods Twenty-four human third molars were used for microtensile bond strength testing of G-Bond and Clearfil S3 Bond. The dentin surface was either blot-dried or air-dried before applying these adhesive agents. After application of the adhesive agent, three different air drying times were evaluated: 1, 5, and 10 sec. Composite resin was build up to 4 mm thickness and light cured for 40 sec with 2 separate layers. Then the tooth was sectioned and trimmed to measure the microtensile bond strength using a universal testing machine. The measured bond strengths were analyzed with three-way ANOVA and regression analysis was done (p = 0.05). Results All three factors, materials, dentin wetness and air drying time, showed significant effect on the microtensile bond strength. Clearfil S3 Bond, dry dentin surface and 10 sec air drying time showed higher bond strength. Conclusions Within the limitation of this experiment, air drying time after the application of the one-step self-etching adhesive agent was the most significant factor affecting the bond strength, followed by the material difference and dentin moisture before applying the adhesive agent. PMID:23429228

  4. Leap Frog and Time Step Sub-Cycle Scheme for Coupled Neutronics and Thermal-Hydraulic Codes

    SciTech Connect

    Lu, S.

    2002-07-01

    As the result of the advancing TCP/IP based inter-process communication technology, more and more legacy thermal-hydraulic codes have been coupled with neutronics codes to provide best-estimate capabilities for reactivity related reactor transient analysis. Most of the coupling schemes are based on closely coupled serial or parallel approaches. Therefore, the execution of the coupled codes usually requires significant CPU time, when a complicated system is analyzed. Leap Frog scheme has been used to reduce the run time. The extent of the decoupling is usually determined based on a trial and error process for a specific analysis. It is the intent of this paper to develop a set of general criteria, which can be used to invoke the automatic Leap Frog algorithm. The algorithm will not only provide the run time reduction but also preserve the accuracy. The criteria will also serve as the base of an automatic time step sub-cycle scheme when a sudden reactivity change is introduced and the thermal-hydraulic code is marching with a relatively large time step. (authors)

  5. Higher-order hybrid implicit/explicit FDTD time-stepping

    NASA Astrophysics Data System (ADS)

    Tierens, W.

    2016-12-01

    Both partially implicit FDTD methods, and symplectic FDTD methods of high temporal accuracy (3rd or 4th order), are well documented in the literature. In this paper we combine them: we construct a conservative FDTD method which is fourth order accurate in time and is partially implicit. We show that the stability condition for this method depends exclusively on the explicit part, which makes it suitable for use in e.g. modelling wave propagation in plasmas.

  6. Paper Laser: a step towards a time scale generation from an ensemble of optical clocks

    NASA Astrophysics Data System (ADS)

    Ortiz, C. A.; de Carlos, E.; Lopez, J. M.

    2016-06-01

    In this paper a simple and innovative technique to combine n optical frequencies with the aim to produce a virtual laser with superior metrological characteristics is introduced. The algorithms to combine a number of clocks to produce a virtual clock, which is also referred as paper clock, are well known. An example of this is the statistical generation of the UTC time scale by the Bureau International des Poids et Mesures (BIPM) using a recursive algorithm (ALGOS). A similar algorithm to combine n optical frequencies, all of them with same nominal value, to produce a “paper laser” whose frequency is known through its difference with respect to the optical frequencies of the ensemble is proposed here. As a demonstration of this, three optical frequencies stabilized to the D2 Cs-133 line, all of them with similar frequency stability were experimentally combined. A paper laser has been produced during hours whose frequency stability is about 3-1/2 times with respect to the original optical frequencies. This technique can be applied to combine ultra-stable optical frequencies to produce a paper laser that can be materialized by correcting one of the real optical frequencies of the ensemble. The robustness and stability of a paper laser is very attractive to produce a time scale from its operation.

  7. Issues in measure-preserving three dimensional flow integrators: Self-adjointness, reversibility, and non-uniform time stepping

    NASA Astrophysics Data System (ADS)

    Finn, John M.

    2015-03-01

    Properties of integration schemes for solenoidal fields in three dimensions are studied, with a focus on integrating magnetic field lines in a plasma using adaptive time stepping. It is shown that implicit midpoint (IM) and a scheme we call three-dimensional leapfrog (LF) can do a good job (in the sense of preserving KAM tori) of integrating fields that are reversible, or (for LF) have a "special divergence-free" (SDF) property. We review the notion of a self-adjoint scheme, showing that such schemes are at least second order accurate and can always be formed by composing an arbitrary scheme with its adjoint. We also review the concept of reversibility, showing that a reversible but not exactly volume-preserving scheme can lead to a fractal invariant measure in a chaotic region, although this property may not often be observable. We also show numerical results indicating that the IM and LF schemes can fail to preserve KAM tori when the reversibility property (and the SDF property for LF) of the field is broken. We discuss extensions to measure preserving flows, the integration of magnetic field lines in a plasma and the integration of rays for several plasma waves. The main new result of this paper relates to non-uniform time stepping for volume-preserving flows. We investigate two potential schemes, both based on the general method of Feng and Shang [Numer. Math. 71, 451 (1995)], in which the flow is integrated in split time steps, each Hamiltonian in two dimensions. The first scheme is an extension of the method of extended phase space, a well-proven method of symplectic integration with non-uniform time steps. This method is found not to work, and an explanation is given. The second method investigated is a method based on transformation to canonical variables for the two split-step Hamiltonian systems. This method, which is related to the method of non-canonical generating functions of Richardson and Finn [Plasma Phys. Controlled Fusion 54, 014004 (2012

  8. Issues in measure-preserving three dimensional flow integrators: Self-adjointness, reversibility, and non-uniform time stepping

    DOE PAGES

    Finn, John M.

    2015-03-01

    Properties of integration schemes for solenoidal fields in three dimensions are studied, with a focus on integrating magnetic field lines in a plasma using adaptive time stepping. It is shown that implicit midpoint (IM) and a scheme we call three-dimensional leapfrog (LF) can do a good job (in the sense of preserving KAM tori) of integrating fields that are reversible, or (for LF) have a 'special divergence-free' property. We review the notion of a self-adjoint scheme, showing that such schemes are at least second order accurate and can always be formed by composing an arbitrary scheme with its adjoint. Wemore » also review the concept of reversibility, showing that a reversible but not exactly volume-preserving scheme can lead to a fractal invariant measure in a chaotic region, although this property may not often be observable. We also show numerical results indicating that the IM and LF schemes can fail to preserve KAM tori when the reversibility property (and the SDF property for LF) of the field is broken. We discuss extensions to measure preserving flows, the integration of magnetic field lines in a plasma and the integration of rays for several plasma waves. The main new result of this paper relates to non-uniform time stepping for volume-preserving flows. We investigate two potential schemes, both based on the general method of Ref. [11], in which the flow is integrated in split time steps, each Hamiltonian in two dimensions. The first scheme is an extension of the method of extended phase space, a well-proven method of symplectic integration with non-uniform time steps. This method is found not to work, and an explanation is given. The second method investigated is a method based on transformation to canonical variables for the two split-step Hamiltonian systems. This method, which is related to the method of non-canonical generating functions of Ref. [35], appears to work very well.« less

  9. Issues in measure-preserving three dimensional flow integrators: Self-adjointness, reversibility, and non-uniform time stepping

    SciTech Connect

    Finn, John M.

    2015-03-15

    Properties of integration schemes for solenoidal fields in three dimensions are studied, with a focus on integrating magnetic field lines in a plasma using adaptive time stepping. It is shown that implicit midpoint (IM) and a scheme we call three-dimensional leapfrog (LF) can do a good job (in the sense of preserving KAM tori) of integrating fields that are reversible, or (for LF) have a “special divergence-free” (SDF) property. We review the notion of a self-adjoint scheme, showing that such schemes are at least second order accurate and can always be formed by composing an arbitrary scheme with its adjoint. We also review the concept of reversibility, showing that a reversible but not exactly volume-preserving scheme can lead to a fractal invariant measure in a chaotic region, although this property may not often be observable. We also show numerical results indicating that the IM and LF schemes can fail to preserve KAM tori when the reversibility property (and the SDF property for LF) of the field is broken. We discuss extensions to measure preserving flows, the integration of magnetic field lines in a plasma and the integration of rays for several plasma waves. The main new result of this paper relates to non-uniform time stepping for volume-preserving flows. We investigate two potential schemes, both based on the general method of Feng and Shang [Numer. Math. 71, 451 (1995)], in which the flow is integrated in split time steps, each Hamiltonian in two dimensions. The first scheme is an extension of the method of extended phase space, a well-proven method of symplectic integration with non-uniform time steps. This method is found not to work, and an explanation is given. The second method investigated is a method based on transformation to canonical variables for the two split-step Hamiltonian systems. This method, which is related to the method of non-canonical generating functions of Richardson and Finn [Plasma Phys. Controlled Fusion 54, 014004 (2012

  10. NIH and WHI: time for a mea culpa and steps beyond.

    PubMed

    Utian, Wulf H

    2007-01-01

    The termination of the estrogen-progestin arm of the Women's Health Initiative (WHI) 5 years ago was abrupt and poorly planned. It has also become manifestly clear that the reporting at that time of the balance of risk and benefit for perimenopausal and early postmenopausal women was grossly exaggerated. Subsequent WHI publications including subanalyses of original data suggest a persistent pattern of over-reading of results toward a negative bias. The initial 2002 conclusion of the WHI investigators that harm was greater than benefit appears to be the result of several factors. One was the failure to recognize that initiation of therapy by decade of age or time since menopause was highly relevant; the WHI committee aggregated all outcome data into one group, even though in their demographic description they had the ability to investigate by age. An overhanging question is, therefore, what did they know, and when did they know it? Another factor was the utilization of a nonvalidated index termed the "global health index" that inexplicably assumed for comparison sake that all diseases were equivalent, for example, that a stroke was equivalent to a hip fracture in morbidity, mortality, and impact on quality of life. Although not a study about menopause, the data were extrapolated to all peri- and postmenopausal women. Despite the overall positive outcome of their results for women aged 50 to 60 years, most particularly those receiving estrogen-only therapy, the WHI investigators have irrationally maintained a defense of their misinterpretations of 2002. It is time for the National Institutes of Health and the WHI investigators to issue a final overall report that is clear and based on their actual results and not their personal interpretations. There is too much relevant and important information within the WHI to allow the overall study to continue to be perceived as biased to the detriment of both the National Institutes of Health and the study itself.

  11. Phase-adjusted echo time (PATE)-averaging 1H MRS: application for improved glutamine quantification at 2.89 T

    PubMed Central

    Prescot, Andrew P.; Richards, Todd; Dager, Stephen R.; Choi, Changho; Renshaw, Perry F.

    2015-01-01

    1H MRS investigations have reported altered glutamatergic neurotransmission in a variety of psychiatric disorders. The unraveling of glutamate from glutamine resonances is crucial for the interpretation of these observations, although this remains a challenge at clinical static magnetic field strengths. Glutamate resolution can be improved through an approach known as echo time (TE) averaging, which involves the acquisition and subsequent averaging of multiple TE steps. The process of TE averaging retains the central component of the glutamate methylene multiplet at 2.35 ppm, with the simultaneous attenuation of overlapping phase-modulated coupled resonances of glutamine and N-acetylaspartate. We have developed a novel post-processing approach, termed phase-adjusted echo time (PATE) averaging, for the retrieval of glutamine signals from a TE-averaged 1H MRS dataset. The method works by the application of an optimal TE-specific phase term, which is derived from spectral simulation, prior to averaging over TE space. The simulation procedures and preliminary in vivo spectra acquired from the human frontal lobe at 2.89 T are presented. Three metabolite normalization schemes were developed to evaluate the frontal lobe test–retest reliability for glutamine measurement in six subjects, and the resulting values were comparable with previous reports for within-subject (9–14%) and inter-subject (14–20%) measures. Using the acquisition parameters and TE range described, glutamine quantification is possible in approximately 10 min. The post-processing methods described can also be applied retrospectively to extract glutamine and glutamate levels from previously acquired TE-averaged 1H MRS datasets. PMID:22407923

  12. Adjustment of interaural time difference in head related transfer functions based on listeners' anthropometry and its effect on sound localization

    NASA Astrophysics Data System (ADS)

    Suzuki, Yôiti; Watanabe, Kanji; Iwaya, Yukio; Gyoba, Jiro; Takane, Shouichi

    2005-04-01

    Because the transfer functions governing subjective sound localization (HRTFs) show strong individuality, sound localization systems based on synthesis of HRTFs require suitable HRTFs for individual listeners. However, it is impractical to obtain HRTFs for all listeners based on measurements. Improving sound localization by adjusting non-individualized HRTFs to a specific listener based on that listener's anthropometry might be a practical method. This study first developed a new method to estimate interaural time differences (ITDs) using HRTFs. Then correlations between ITDs and anthropometric parameters were analyzed using the canonical correlation method. Results indicated that parameters relating to head size, and shoulder and ear positions are significant. Consequently, it was attempted to express ITDs based on listener's anthropometric data. In this process, the change of ITDs as a function of azimuth angle was parameterized as a sum of sine functions. Then the parameters were analyzed using multiple regression analysis, in which the anthropometric parameters were used as explanatory variables. The predicted or individualized ITDs were installed in the nonindividualized HRTFs to evaluate sound localization performance. Results showed that individualization of ITDs improved horizontal sound localization.

  13. One-step Real-time Food Quality Analysis by Simultaneous DSC-FTIR Microspectroscopy.

    PubMed

    Lin, Shan-Yang; Lin, Chih-Cheng

    2016-01-01

    This review discusses an analytical technique that combines differential scanning calorimetry and Fourier-transform infrared (DSC-FTIR) microspectroscopy, which simulates the accelerated stability test and detects decomposition products simultaneously in real time. We show that the DSC-FTIR technique is a fast, simple and powerful analytical tool with applications in food sciences. This technique has been applied successfully to the simultaneous investigation of: encapsulated squid oil stability; the dehydration and intramolecular condensation of sweetener (aspartame); the dehydration, rehydration and solidification of trehalose; and online monitoring of the Maillard reaction for glucose (Glc)/asparagine (Asn) in the solid state. This technique delivers rapid and appropriate interpretations with food science applications.

  14. Steps Toward Real-Time Atmospheric Phase Fluctuation Correction for a High Resolution Radar System

    NASA Astrophysics Data System (ADS)

    Denn, Grant R.; Geldzahler, Barry; Birr, Rick; Brown, Robert; Hoblitzell, Richard; Grant, Kevin; Miller, Michael; Woods, Gary; Archuleta, Arby; Ciminera, Michael; Cornish, Timothy; davarian, faramaz; kocz, jonathan; lee, dennis; Morabito, David Dominic; Soriano, Melissa; Tsao, Philip; Vilnrotter, Victor; Jakeman-Flores, Hali; Ott, melanie; Thomes, W. Joe; Soloff, Jason; NASA Kennedy Space Center, Jet Propulsion Laboratory, NASA Goddard Space Flight Center, NASA Johnson Space Flight Center, Metropolitan State University of Denver

    2016-01-01

    NASA is pursuing a demonstration of coherent uplink arraying at 7.145-7.190 GHz (X-band) and 30-31 GHz (Ka-band) using three 12m diameter COTS antennas separated by 60m at the Kennedy Space Center in Florida, with the goal of a high-power, high-resolution radar array that employs real-time correction for tropospheric phase fluctuation. The major uses for this array will be (a) observations of Near Earth Objects, (b) detection and tracking of orbital debris, (c) high power emergency uplink capability for spacecraft, and (d) radio science experiments.

  15. Kalman Filtered Daily GRACE Gravity Field Solutions in Near Real-Time- First Steps

    NASA Astrophysics Data System (ADS)

    Kvas, Andreas; Mayer-Gurr, Torsten

    2016-08-01

    As part of the EGSIEM (European Gravity Service for Improved Emergency Management) project, a technology demonstrator for a near real-time (NRT) gravity field service will be established. In preparation of the operational phase, several aspects of the daily gravity field processing chain at Graz University of Technology have been inspected in order to improve the gravity field solutions and move towards NRT. The effect of these adaptions is investigated by comparison with post-processing and forward-only filtered solutions and evaluated using in-situ data.

  16. Steps toward thin film metal thermistors with microsecond time response for shock temperature measurements of polymers

    NASA Astrophysics Data System (ADS)

    Taylor, N. E.; Williamson, D. M.; Jardine, A. P.

    2014-05-01

    Equations of state can be used to predict the relationship between pressure, volume and temperature. However, in shock physics, they are usually only constrained by experimental observations of pressure and volume. Direct observation of temperature in a shock is therefore valuable in constraining equations of state. Bloomquist and Sheffield (1980, 1981) and Rosenberg and Partom (1984) have attempted such observations in poly(methyl methacrylate) (PMMA). However, their results disagree strongly above 2GPa shock pressure. Here we present an improved fabrication technique, to examine this outstanding issue. We make use of the fact that the electrical resistivity of most metals is a known function of both pressure and temperature. If the change in resistance of a thin metal thermistor gauge is measured during a shock experiment of known pressure, the temperature can be calculated directly. The time response is limited by the time taken for the gauge to reach thermal equilibrium with the medium in which it is embedded. Gold gauges of thickness up to 200 nm have been produced by thermal evaporation, and fully embedded in PMMA. These reach thermal equilibrium with the host material in under 1 us, allowing temperature measurement within the duration of a plate impact experiment.

  17. Acceleration of Ab Initio QM/MM Calculations under Periodic Boundary Conditions by Multiscale and Multiple Time Step Approaches.

    PubMed

    Nam, Kwangho

    2014-10-14

    Development of multiscale ab initio quantum mechanical and molecular mechanical (AI-QM/MM) method for periodic boundary molecular dynamics (MD) simulations and their acceleration by multiple time step approach are described. The developed method achieves accuracy and efficiency by integrating the AI-QM/MM level of theory and the previously developed semiempirical (SE) QM/MM-Ewald sum method [J. Chem. Theory Comput. 2005, 1, 2] extended to the smooth particle-mesh Ewald (PME) summation method. In the developed methods, the total energy of the simulated system is evaluated at the SE-QM/MM-PME level of theory to include long-range QM/MM electrostatic interactions, which is then corrected on the fly using the AI-QM/MM level of theory within the real space cutoff. The resulting energy expression enables decomposition of total forces applied to each atom into forces determined at the low-level SE-QM/MM method and correction forces at the AI-QM/MM level, to integrate the system using the reversible reference system propagator algorithm. The resulting method achieves a substantial speed-up of the entire calculation by minimizing the number of time-consuming energy and gradient evaluations at the AI-QM/MM level. Test calculations show that the developed multiple time step AI-QM/MM method yields MD trajectories and potential of mean force profiles comparable to single time step QM/MM results. The developed method, together with message passing interface (MPI) parallelization, accelerates the present AI-QM/MM MD simulations about 30-fold relative to the speed of single-core AI-QM/MM simulations for the molecular systems tested in the present work, making the method less than one order slower than the SE-QM/MM methods under periodic boundary conditions.

  18. In the time of significant generational diversity - surgical leadership must step up!

    PubMed

    Money, Samuel R; O'Donnell, Mark E; Gray, Richard J

    2014-02-01

    The diverse attitudes and motivations of surgeons and surgical trainees within different age groups present an important challenge for surgical leaders and educators. These challenges to surgical leadership are not unique, and other industries have likewise needed to grapple with how best to manage these various age groups. The authors will herein explore management and leadership for surgeons in a time of age diversity, define generational variations within "Baby-Boomer", "Generation X" and "Generation Y" populations, and identify work ethos concepts amongst these three groups. The surgical community must understand and embrace these concepts in order to continue to attract a stellar pool of applicants from medical school. By not accepting the changing attitudes and motivations of young trainees and medical students, we may disenfranchise a high percentage of potential future surgeons. Surgical training programs will fill, but will they contain the highest quality trainees?

  19. Longitudinal associations between personality profile stability and adjustment in college students: distinguishing among overall stability, distinctive stability, and within-time normativeness.

    PubMed

    Klimstra, Theo A; Luyckx, Koen; Hale, William W; Goossens, Luc; Meeus, Wim H J

    2010-08-01

    In the present study, longitudinal associations of 3 aspects of personality profile stability (i.e., overall stability, distinctive stability, and within-time normativeness) with 3 adjustment measures (i.e., depressive symptoms, self-esteem, and delinquency) were examined, using 4 waves of longitudinal data on a Belgian college sample (N=565). Longitudinal path models revealed strong longitudinal associations between adjustment and overall stability. Subsequent analyses showed that it is not the degree to which one's personality profile consistently diverges from the average personality profile within a population (i.e., distinctive stability) that is related to adjustment but the degree to which a personality profile of an individual matches the average personality profile within the sample at a certain point in time (i.e., within-time normativeness). The current study thereby underscores the importance of distinguishing normativeness and distinctiveness when examining personality profile stability.

  20. Changing Safety Culture, One Step at a Time: The Value of the DOE-VPP Program at PNNL

    SciTech Connect

    Wright, Patrick A.; Isern, Nancy G.

    2005-02-01

    The primary value of the Pacific Northwest National Laboratory (PNNL) Voluntary Protection Program (VPP) is the ongoing partnership between management and staff committed to change Laboratory safety culture one step at a time. VPP enables PNNL's safety and health program to transcend a top-down, by-the-book approach to safety, and it also raises grassroots safety consciousness by promoting a commitment to safety and health 24 hours a day, 7 days a week. PNNL VPP is a dynamic, evolving program that fosters innovative approaches to continuous improvement in safety and health performance at the Laboratory.

  1. A quantitative method for evaluating numerical simulation accuracy of time-transient Lamb wave propagation with its applications to selecting appropriate element size and time step.

    PubMed

    Wan, Xiang; Xu, Guanghua; Zhang, Qing; Tse, Peter W; Tan, Haihui

    2016-01-01

    Lamb wave technique has been widely used in non-destructive evaluation (NDE) and structural health monitoring (SHM). However, due to the multi-mode characteristics and dispersive nature, Lamb wave propagation behavior is much more complex than that of bulk waves. Numerous numerical simulations on Lamb wave propagation have been conducted to study its physical principles. However, few quantitative studies on evaluating the accuracy of these numerical simulations were reported. In this paper, a method based on cross correlation analysis for quantitatively evaluating the simulation accuracy of time-transient Lamb waves propagation is proposed. Two kinds of error, affecting the position and shape accuracies are firstly identified. Consequently, two quantitative indices, i.e., the GVE (group velocity error) and MACCC (maximum absolute value of cross correlation coefficient) derived from cross correlation analysis between a simulated signal and a reference waveform, are proposed to assess the position and shape errors of the simulated signal. In this way, the simulation accuracy on the position and shape is quantitatively evaluated. In order to apply this proposed method to select appropriate element size and time step, a specialized 2D-FEM program combined with the proposed method is developed. Then, the proper element size considering different element types and time step considering different time integration schemes are selected. These results proved that the proposed method is feasible and effective, and can be used as an efficient tool for quantitatively evaluating and verifying the simulation accuracy of time-transient Lamb wave propagation.

  2. Review of Real-Time Simulator and the Steps Involved for Implementation of a Model from MATLAB/SIMULINK to Real-Time

    NASA Astrophysics Data System (ADS)

    Mikkili, Suresh; Panda, Anup Kumar; Prattipati, Jayanthi

    2014-07-01

    Nowadays the researchers want to develop their model in real-time environment. Simulation tools have been widely used for the design and improvement of electrical systems since the mid twentieth century. The evolution of simulation tools has progressed in step with the evolution of computing technologies. In recent years, computing technologies have improved dramatically in performance and become widely available at a steadily decreasing cost. Consequently, simulation tools have also seen dramatic performance gains and steady cost decreases. Researchers and engineers now have the access to affordable, high performance simulation tools that were previously too cost prohibitive, except for the largest manufacturers. This work has introduced a specific class of digital simulator known as a real-time simulator by answering the questions "what is real-time simulation", "why is it needed" and "how it works". The latest trend in real-time simulation consists of exporting simulation models to FPGA. In this article, the Steps involved for implementation of a model from MATLAB to REAL-TIME are provided in detail.

  3. Length and time for development of laminar flow in tubes following a step increase of volume flux

    NASA Astrophysics Data System (ADS)

    Chaudhury, Rafeed A.; Herrmann, Marcus; Frakes, David H.; Adrian, Ronald J.

    2015-01-01

    Laminar flows starting up from rest in round tubes are relevant to numerous industrial and biomedical applications. The two most common types are flows driven by an abruptly imposed constant pressure gradient or by an abruptly imposed constant volume flux. Analytical solutions are available for transient, fully developed flows, wherein streamwise development over the entrance length is absent (Szymanski in J de Mathématiques Pures et Appliquées 11:67-107, 1932; Andersson and Tiseth in Chem Eng Commun 112(1):121-133, 1992, respectively). They represent the transient responses of flows in tubes that are very long compared with the entrance length, a condition that is seldom satisfied in biomedical tube networks. This study establishes the entrance (development) length and development time of starting laminar flow in a round tube of finite length driven by a piston pump that produces a step change from zero flow to a constant volume flux for Reynolds numbers between 500 and 3,000. The flows are examined experimentally, using stereographic particle image velocimetry and computationally using computational fluid dynamics, and are then compared with the known analytical solutions for fully developed flow conditions in infinitely long tubes. Results show that step function volume flux start-up flows reach steady state and fully developed flow five times more quickly than those driven by a step function pressure gradient, a 500 % change when compared with existing estimates. Based on these results, we present new, simple guidelines for achieving experimental flows that are fully developed in space and time in realistic (finite) tube geometries. To a first approximation, the time to achieve steady spatially developing flow is nearly equal to the time needed to achieve steady, fully developed flow. Conversely, the entrance length needed to achieve fully developed transient flow is approximately equal to the length needed to achieve fully developed steady flow. Beyond this

  4. Contribution of hind limb flexor muscle afferents to the timing of phase transitions in the cat step cycle.

    PubMed

    Hiebert, G W; Whelan, P J; Prochazka, A; Pearson, K G

    1996-03-01

    1. In this investigation, we tested the hypothesis that muscle spindle afferents signaling the length of hind-leg flexor muscles are involved in terminating extensor activity and initiating flexion during walking. The hip flexor muscle iliopsoas (IP) and the ankle flexors tibialis anterior (TA) and extensor digitorum longus (EDL) were stretched or vibrated at various phases of the step cycle in spontaneously walking decerebrate cats. Changes in electromyogram amplitude, duration, and timing were then examined. The effects of electrically stimulating group I and II afferents in the nerves to TA and EDL also were examined. 2. Stretch of the individual flexor muscles (IP, TA, or EDL) during the stance phase reduced the duration of extensor activity and promoted the onset of flexor burst activity. The contralateral step cycle also was affected by the stretch, the duration of flexor activity being shortened and extensor activity occurring earlier. Therefore, stretch of the flexor muscles during the stance phase reset the locomotor rhythm to flexion ipsilaterally and extension contralaterally. 3. Results of electrically stimulating the afferents from the TA and EDL muscles suggested that different groups of afferents were responsible for the resetting of the step cycle. Stimulation of the TA nerve reset the locomotor step cycle when the stimulus intensity was in the group II range (2-5 xT). By contrast, stimulation of the EDL nerve generated strong resetting of the step cycle in the range of 1.2-1.4 xT, where primarily the group Ia afferents from the muscle spindles would be activated. 4. Vibration of IP or EDL during stance reduced the duration of the extensor activity by similar amounts to that produced by muscle stretch or by electrical stimulation of EDL at group Ia strengths. This suggests that the group Ia afferents from IP and EDL are capable of resetting the locomotor pattern generator. Vibration of TA did not affect the locomotor rhythm. 5. Stretch of IP or

  5. The STEP model: Characterizing simultaneous time effects on practice for flight simulator performance among middle-aged and older pilots.

    PubMed

    Kennedy, Quinn; Taylor, Joy; Noda, Art; Yesavage, Jerome; Lazzeroni, Laura C

    2015-09-01

    Understanding the possible effects of the number of practice sessions (practice) and time between practice sessions (interval) among middle-aged and older adults in real-world tasks has important implications for skill maintenance. Prior training and cognitive ability may impact practice and interval effects on real-world tasks. In this study, we took advantage of existing practice data from 5 simulated flights among 263 middle-aged and older pilots with varying levels of flight expertise (defined by U.S. Federal Aviation Administration proficiency ratings). We developed a new Simultaneous Time Effects on Practice (STEP) model: (a) to model the simultaneous effects of practice and interval on performance of the 5 flights, and (b) to examine the effects of selected covariates (i.e., age, flight expertise, and 3 composite measures of cognitive ability). The STEP model demonstrated consistent positive practice effects, negative interval effects, and predicted covariate effects. Age negatively moderated the beneficial effects of practice. Additionally, cognitive processing speed and intraindividual variability (IIV) in processing speed moderated the benefits of practice and/or the negative influence of interval for particular flight performance measures. Expertise did not interact with practice or interval. Results indicated that practice and interval effects occur in simulated flight tasks. However, processing speed and IIV may influence these effects, even among high-functioning adults. Results have implications for the design and assessment of training interventions targeted at middle-aged and older adults for complex real-world tasks.

  6. The STEP model: Characterizing simultaneous time effects on practice for flight simulator performance among middle-aged and older pilots

    PubMed Central

    Kennedy, Quinn; Taylor, Joy; Noda, Art; Yesavage, Jerome; Lazzeroni, Laura C.

    2015-01-01

    Understanding the possible effects of the number of practice sessions (practice) and time between practice sessions (interval) among middle-aged and older adults in real world tasks has important implications for skill maintenance. Prior training and cognitive ability may impact practice and interval effects on real world tasks. In this study, we took advantage of existing practice data from five simulated flights among 263 middle-aged and older pilots with varying levels of flight expertise (defined by FAA proficiency ratings). We developed a new STEP (Simultaneous Time Effects on Practice) model to: (1) model the simultaneous effects of practice and interval on performance of the five flights, and (2) examine the effects of selected covariates (age, flight expertise, and three composite measures of cognitive ability). The STEP model demonstrated consistent positive practice effects, negative interval effects, and predicted covariate effects. Age negatively moderated the beneficial effects of practice. Additionally, cognitive processing speed and intra-individual variability (IIV) in processing speed moderated the benefits of practice and/or the negative influence of interval for particular flight performance measures. Expertise did not interact with either practice or interval. Results indicate that practice and interval effects occur in simulated flight tasks. However, processing speed and IIV may influence these effects, even among high functioning adults. Results have implications for the design and assessment of training interventions targeted at middle-aged and older adults for complex real world tasks. PMID:26280383

  7. Universal steps in quantum dynamics with time-dependent potential-energy surfaces: Beyond the Born-Oppenheimer picture

    NASA Astrophysics Data System (ADS)

    Albareda, Guillermo; Abedi, Ali; Tavernelli, Ivano; Rubio, Angel

    2016-12-01

    It was recently shown [G. Albareda et al., Phys. Rev. Lett. 113, 083003 (2014)], 10.1103/PhysRevLett.113.083003 that within the conditional decomposition approach to the coupled electron-nuclear dynamics, the electron-nuclear wave function can be exactly decomposed into an ensemble of nuclear wave packets effectively governed by nuclear conditional time-dependent potential-energy surfaces (C-TDPESs). Employing a one-dimensional model system, we show that for strong nonadiabatic couplings the nuclear C-TDPESs exhibit steps that bridge piecewise adiabatic Born-Oppenheimer potential-energy surfaces. The nature of these steps is identified as an effect of electron-nuclear correlation. Furthermore, a direct comparison with similar discontinuities recently reported in the context of the exact factorization framework allows us to draw conclusions about the universality of these discontinuities, viz., they are inherent to all nonadiabatic nuclear dynamics approaches based on (exact) time-dependent potential-energy surfaces.

  8. Effect of different air-drying time on the microleakage of single-step self-etch adhesives

    PubMed Central

    Moosavi, Horieh; Managhebi, Esmatsadat

    2013-01-01

    Objectives This study evaluated the effect of three different air-drying times on microleakage of three self-etch adhesive systems. Materials and Methods Class I cavities were prepared for 108 extracted sound human premolars. The teeth were divided into three main groups based on three different adhesives: Opti Bond All in One (OBAO), Clearfil S3 Bond (CSB), Bond Force (BF). Each main group divided into three subgroups regarding the air-drying time: without application of air stream, following the manufacturer's instruction, for 10 sec more than manufacturer's instruction. After completion of restorations, specimens were thermocycled and then connected to a fluid filtration system to evaluate microleakage. The data were statistically analyzed using two-way ANOVA and Tukey-test (α = 0.05). Results The microleakage of all adhesives decreased when the air-drying time increased from 0 sec to manufacturer's instruction (p < 0.001). The microleakage of BF reached its lowest values after increasing the drying time to 10 sec more than the manufacturer's instruction (p < 0.001). Microleakage of OBAO and CSB was significantly lower compared to BF in all three drying time (p < 0.001). Conclusions Increasing in air-drying time of adhesive layer in one-step self-etch adhesives caused reduction of microleakage, but the amount of this reduction may be dependent on the adhesive components of self-etch adhesives. PMID:23741709

  9. An explicit large time step particle-in-cell scheme for nonlinear gyrokinetic simulations in the electromagnetic regime

    NASA Astrophysics Data System (ADS)

    Kleiber, R.; Hatzky, R.; Könies, A.; Mishchenko, A.; Sonnendrücker, E.

    2016-03-01

    A new algorithm for electromagnetic gyrokinetic simulations, the so called "pullback transformation scheme" proposed by Mishchenko et al. [Phys. Plasmas 21, 092110 (2014)] is motivated as an explicit time integrator reset after each full timestep and investigated in detail. Using a numerical dispersion relation valid in slab geometry, it is shown that the linear properties of the scheme are comparable to those of an implicit v∥ -scheme. A nonlinear extension of the mixed variable formulation, derived consistently from a field Lagrangian, is proposed. The scheme shows excellent numerical properties with a low statistical noise level and a large time step especially for MHD modes. The example of a nonlinear slab tearing mode simulation is used to illustrate the properties of different formulations of the physical model equations.

  10. Extension of an explicit finite volume method to large time steps (CFL>1): application to shallow water flows

    NASA Astrophysics Data System (ADS)

    Murillo, J.; García-Navarro, P.; Brufau, P.; Burguete, J.

    2006-01-01

    In this work, the explicit first order upwind scheme is presented under a formalism that enables the extension of the methodology to large time steps. The number of cells in the stencil of the numerical scheme is related to the allowable size of the CFL number for numerical stability. It is shown how to increase both at the same time. The basic idea is proposed for a 1D scalar equation and extended to 1D and 2D non-linear systems with source terms. The importance of the kind of grid used is highlighted and the method is outlined for irregular grids. The good quality of the results is illustrated by means of several examples including shallow water flow test cases. The bed slope source terms are involved in the method through an upwind discretization.

  11. A simple test of choice stepping reaction time for assessing fall risk in people with multiple sclerosis.

    PubMed

    Tijsma, Mylou; Vister, Eva; Hoang, Phu; Lord, Stephen R

    2017-03-01

    Purpose To determine (a) the discriminant validity for established fall risk factors and (b) the predictive validity for falls of a simple test of choice stepping reaction time (CSRT) in people with multiple sclerosis (MS). Method People with MS (n = 210, 21-74y) performed the CSRT, sensorimotor, balance and neuropsychological tests in a single session. They were then followed up for falls using monthly fall diaries for 6 months. Results The CSRT test had excellent discriminant validity with respect to established fall risk factors. Frequent fallers (≥3 falls) performed significantly worse in the CSRT test than non-frequent fallers (0-2 falls). With the odds of suffering frequent falls increasing 69% with each SD increase in CSRT (OR = 1.69, 95% CI: 1.27-2.26, p = <0.001). In regression analysis, CSRT was best explained by sway, time to complete the 9-Hole Peg test, knee extension strength of the weaker leg, proprioception and the time to complete the Trails B test (multiple R(2  )= ( )0.449, p < 0.001). Conclusions A simple low tech CSRT test has excellent discriminative and predictive validity in relation to falls in people with MS. This test may prove useful in documenting longitudinal changes in fall risk in relation to MS disease progression and effects of interventions. Implications for rehabilitation Good choice stepping reaction time (CSRT) is required for maintaining balance. A simple low-tech CSRT test has excellent discriminative and predictive validity in relation to falls in people with MS. This test may prove useful documenting longitudinal changes in fall risk in relation to MS disease progression and effects of interventions.

  12. Dempster-Shafer regression for multi-step-ahead time-series prediction towards data-driven machinery prognosis

    NASA Astrophysics Data System (ADS)

    Niu, Gang; Yang, Bo-Suk

    2009-04-01

    Predicting a sequence of future values of a time series using the descriptors observed in the past can be regarded as the stand-stone of data-driven machinery prognosis. The purpose of this paper is to develop a novel data-driven machinery prognosis strategy for industry application. First, the collected time-series degradation features are reconstructed based on the theorem of Takens, among which the reconstruction parameters, delay time and embedding dimension are selected by the C-C method and the false nearest neighbor method, respectively. Next, the Dempster-Shafer regression technique is developed to perform the task of time-series prediction. Moreover, the strategy of iterated multi-step-ahead prediction is discussed to keep track with the rapid variation of time-series signals during the data monitoring process in an industrial plant. The proposed scheme is validated using condition monitoring data of a methane compressor to predict the degradation trend. Experimental results show that the proposed methods have a low error rate; hence, it can be regarded as an effective tool for data-driven machinery prognosis applications.

  13. First generic one step real-time Taqman RT-PCR targeting the RNA1 of betanodaviruses.

    PubMed

    Baud, M; Cabon, J; Salomoni, A; Toffan, A; Panzarin, V; Bigarré, L

    2015-01-01

    The detection of betanodavirus genomic components is a major issue for diagnostics and control of viral nervous necrosis (VNN), a devastating disease affecting fish worldwide. Despite a number of published molecular-based tests, most of them targeting the RNA2 molecule of the virus, diagnostics is still a challenge due to the high genetic diversity within this genus. In the present study, a new one-step real-time RT-PCR (rRT-PCR), targeting RNA1 of most genotypes of betanodaviruses, was proposed and validated. The test detected successfully various isolates of betanodavirus representatives of the four species RGNNV, SJNNV, TPNNV and BFNNV, either produced on cell culture or from clinical samples. It was specific as shown by the absence of signal on samples from healthy sea bass or from field samples of six other fish species without clinical signs of VNN. The assay detected reliably 50-100 copies of plasmids containing the targeted cloned RNA1 region, as well as an infectious dose of virus of 10(2.5)-10(2.85) TCID50/ml. A set of samples was tested by two different laboratories, with similar results, demonstrating the robustness of the test. This is the first one step generic rRT-PCR method for betanodaviruses. It is simple to perform and may be used for first intention diagnostics as well as for confirmation in case of doubtful results obtained with other published tests targeting RNA2.

  14. Two-step feature selection for predicting survival time of patients with metastatic castrate resistant prostate cancer

    PubMed Central

    Shiga, Motoki

    2016-01-01

    Metastatic castrate resistant prostate cancer (mCRPC) is the major cause of death in prostate cancer patients. Even though some options for treatment of mCRPC have been developed, the most effective therapies remain unclear. Thus finding key patient clinical variables related with mCRPC is an important issue for understanding the disease progression mechanism of mCRPC and clinical decision making for these patients. The Prostate Cancer DREAM Challenge is a crowd-based competition to tackle this essential challenge using new large clinical datasets. This paper proposes an effective procedure for predicting global risks and survival times of these patients, aimed at sub-challenge 1a and 1b of the Prostate Cancer DREAM challenge. The procedure implements a two-step feature selection procedure, which first implements sparse feature selection for numerical clinical variables and statistical hypothesis testing of differences between survival curves caused by categorical clinical variables, and then implements a forward feature selection to narrow the list of informative features. Using Cox’s proportional hazards model with these selected features, this method predicted global risk and survival time of patients using a linear model whose input is a median time computed from the hazard model. The challenge results demonstrated that the proposed procedure outperforms the state of the art model by correctly selecting more informative features on both the global risk prediction and the survival time prediction. PMID:27990267

  15. Single step multiplex real-time RT-PCR for H5N1 influenza A virus detection.

    PubMed

    Payungporn, Sunchai; Chutinimitkul, Salin; Chaisingh, Arunee; Damrongwantanapokin, Sudarat; Buranathai, Chantanee; Amonsin, Alongkorn; Theamboonlers, Apiradee; Poovorawan, Yong

    2006-02-01

    H5N1 influenza A virus causes a rapidly fatal systemic disease in domestic poultry and spreads directly from poultry to mammalian species such as leopards, tigers and humans. The aim of this study was to develop a multiplex real-time RT-PCR for rapid detection of H5N1 influenza A virus. The selected primers and various labeled TaqMan MGB reporter probes corresponding to M, H5 and N1 were used in a single step multiplex real-time RT-PCR to simultaneously detect triple fluorescent signals. In order to validate the method, 75 clinical specimens infected with H5N1 isolated from both poultry and mammals, as well as various specimens of other subtypes and RNA from other viral pathogens of poultry and human were tested. The results showed that the multiplex real-time RT-PCR assays can be applied to detect virus suspensions of H5N1 influenza A virus from a wide host range and demonstrated the sensitivity of the assay amounted to approximately 10(2)-10(3)copies/mul. In conclusion, the highlights of this particular method lie in its rapidity, specificity and sensitivity thus rendering it feasible and effective for large-scale screening at times of H5N1 influenza A virus outbreaks.

  16. Stepped mirrored structures for generating true time delays in stationary optical delay line proof-of-principle experiments for application to optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Jansz, Paul Vernon; Wild, Graham; Hinckley, Steven

    2008-01-01

    Conventional time domain Optical Coherence Tomography (OCT) relies on the detection of an interference pattern generated by the interference of backscattered light from the sample and a reference Optical Delay Line (ODL). By referencing the sample interference with the scan depth of the ODL, constructive interference indicates depth in the sample of a reflecting structure. Conventional ODLs used in time domain OCT require some physical movement of a mirror to scan a given depth range. This movement results in instrument degradation. Also in some situations it is necessary to have no moving parts. Stationary ODLs (SODLs) include dual Reflective Spatial Light Modulator (SLM) systems (Type I) and single Transmissive SLM with match-arrayed-waveguide systems (Type II). In this paper, the method of fabrication and characterisation of a number of Stepped Mirrored Structures (SMS) is presented. These structures are intended for later use in proof-of-principle experiments that demonstrate Type II SODL: a six step, 2 mm step depth macro-SMS, an eight step 150 um deep micro-SMS with glue between steps, and a six step 150 um deep micro-SMS with no glue between steps. These SMS are characterized in terms of their fabrication, step alignment and step height increment precision. The degree of alignment of each step was verified using half of a bulk Michelson interferometer. Step height was gauged using a pair of vernier callipers measuring each individual step. A change in notch frequency using an in-fibre Mach-Zhender interferometer was used to gauge the average step height and the result compared to the vernier calliper results. The best aligned SMS was the micro-SMS prepared by method B with no glue between steps. It demonstrated a 95% confidence interval variation of 1% in reflected intensity, with the least variation in intensity within steps. This SMS also had the least absolute variation in step height increment: less than 8 um. Though less variation would be ideal, for

  17. Third-order-accurate numerical methods for efficient, large time-step solutions of mixed linear and nonlinear problems

    SciTech Connect

    Cobb, J.W.

    1995-02-01

    There is an increasing need for more accurate numerical methods for large-scale nonlinear magneto-fluid turbulence calculations. These methods should not only increase the current state of the art in terms of accuracy, but should also continue to optimize other desired properties such as simplicity, minimized computation, minimized memory requirements, and robust stability. This includes the ability to stably solve stiff problems with long time-steps. This work discusses a general methodology for deriving higher-order numerical methods. It also discusses how the selection of various choices can affect the desired properties. The explicit discussion focuses on third-order Runge-Kutta methods, including general solutions and five examples. The study investigates the linear numerical analysis of these methods, including their accuracy, general stability, and stiff stability. Additional appendices discuss linear multistep methods, discuss directions for further work, and exhibit numerical analysis results for some other commonly used lower-order methods.

  18. A Novel Molten Salt Reactor Concept to Implement the Multi-Step Time-Scheduled Transmutation Strategy

    SciTech Connect

    Csom, Gyula; Feher, Sandor; Szieberthj, Mate

    2002-07-01

    Nowadays the molten salt reactor (MSR) concept seems to revive as one of the most promising systems for the realization of transmutation. In the molten salt reactors and subcritical systems the fuel and material to be transmuted circulate dissolved in some molten salt. The main advantage of this reactor type is the possibility of the continuous feed and reprocessing of the fuel. In the present paper a novel molten salt reactor concept is introduced and its transmutation capabilities are studied. The goal is the development of a transmutation technique along with a device implementing it, which yield higher transmutation efficiencies than that of the known procedures and thus results in radioactive waste whose load on the environment is reduced both in magnitude and time length. The procedure is the multi-step time-scheduled transmutation, in which transformation is done in several consecutive steps of different neutron flux and spectrum. In the new MSR concept, named 'multi-region' MSR (MRMSR), the primary circuit is made up of a few separate loops, in which salt-fuel mixtures of different compositions are circulated. The loop sections constituting the core region are only neutronically and thermally coupled. This new concept makes possible the utilization of the spatial dependence of spectrum as well as the advantageous features of liquid fuel such as the possibility of continuous chemical processing etc. In order to compare a 'conventional' MSR and a proposed MRMSR in terms of efficiency, preliminary calculational results are shown. Further calculations in order to find the optimal implementation of this new concept and to emphasize its other advantageous features are going on. (authors)

  19. Development of one-step real-time PCR assay for titrating trivalent live attenuated influenza vaccines

    PubMed Central

    Zang, Yang; Du, Dongchuan; Ge, Peng; Xu, Yongqing; Liu, Xintao; Zhang, Yan; Su, Weiheng; Kiseleva, Irina; Rudenko, Larisa; Xu, Fei; Kong, Wei; Jiang, Chunlai

    2014-01-01

    Traditionally, infectivity of a trivalent live attenuated influenza vaccines (LAIVs) is titrated by determining the 50% egg infectious dose assay (EID50) or plaque forming units (PFU), which requires specific monoclonal antibodies to neutralize 2 strains while estimating the titer of the non-neutralized strain. Compared to this time-consuming, laborious, subjective and variable process, reverse transcription-quantitative real-time PCR (RT-qPCR) technology has advantages of rapidity, sensitivity, reproducibility and reduced contamination, thus has been applied widely for detecting pathogens and measuring viral titers. In this study, the critical harvest time was determined to be 18 h post-infection (hpi) for type A influenza and 12 hpi for type B influenza, but no significant difference between titers at 12 hpi and 18 hpi for the type B strain was observed. In conclusion, trivalent LAIVs can be titrated simultaneously within 24 h by this one-step RT-qPCR assay, which yielded titers comparable to those obtained by the traditional EID50 assay. Therefore, the RT-qPCR assay may be used as a highly specific, sensitive, precise and rapid alternative to the EID50 assay for titering LAIVs. PMID:25483696

  20. Global surface mass time variations by using a two-step inversion for cumulating daily satellite gravity information

    NASA Astrophysics Data System (ADS)

    Ramillien, Guillaume; Frappart, Frappart; Seoane, Lucia

    2015-04-01

    We propose a new method to produce time series of global maps of surface mass variations by progressive integration of daily geopotential variations measured by orbiting satellites. In the case of the GRACE mission (2002 - 2012), these geopotential variations can be determined from very accurate inter-satellite K-Band Range Rate (KBRR) measurements of 5-second daily orbits. In particular, the along-track gravity contribution of hydrology is extracted by removing de-aliasing models for static field, atmosphere, oceans mass variations (including periodical tides), as well as polar movements. Our determination of surface mass sources consists of two successive dependent Kalman filter stages. The first one consists of reducing the satellite-based potential anomalies by adjusting the longest spatial wavelengths (i.e., low-degree spherical harmonics less than 5-6). In the second stage, the residual potential anomalies from the previous stage are used to recover surface mass density changes - in terms of Equivalent-Water Height (EWH) - over a global network of juxtaposed triangular elements. These surface tiles of ~40,000 km x km are imposed to be identical and homogeneously-distributed over the terrestrial sphere, however they can be adapted to the local geometry of the surface mass. Our global approach was tested by inverting simulated hydrology-related geopotential data, and successfully applied to estimate time-varying surface mass densities from real GRACE-based residuals. This strategy of combined Kalman filter-type inversions can also be useful for exploring the possibility of reaching better time and space resolutions for hydrology, that would be hopefully brought by future low altitude geodetic missions.

  1. 20 CFR 655.1114 - Element IV-What are the timely and significant steps an H-1C employer must take to recruit and...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... significant steps an H-1C employer must take to recruit and retain U.S. nurses? 655.1114 Section 655.1114... Workers as Registered Nurses? § 655.1114 Element IV—What are the timely and significant steps an H-1C employer must take to recruit and retain U.S. nurses? (a) The fourth attestation element requires that...

  2. 20 CFR 655.1114 - Element IV-What are the timely and significant steps an H-1C employer must take to recruit and...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Workers as Registered Nurses? § 655.1114 Element IV—What are the timely and significant steps an H-1C... retain sufficient registered nurses who are United States citizens or immigrants who are authorized to... facility on nonimmigrant registered nurses.” The facility must take at least two such steps, unless...

  3. 20 CFR 655.1114 - Element IV-What are the timely and significant steps an H-1C employer must take to recruit and...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Workers as Registered Nurses? § 655.1114 Element IV—What are the timely and significant steps an H-1C... retain sufficient registered nurses who are United States citizens or immigrants who are authorized to... facility on nonimmigrant registered nurses.” The facility must take at least two such steps, unless...

  4. Development of real-time diagnostics and feedback algorithms for JET in view of the next step

    NASA Astrophysics Data System (ADS)

    Murari, A.; Joffrin, E.; Felton, R.; Mazon, D.; Zabeo, L.; Albanese, R.; Arena, P.; Ambrosino, G.; Ariola, M.; Barana, O.; Bruno, M.; Laborde, L.; Moreau, D.; Piccolo, F.; Sartori, F.; Crisanti, F.; de la Luna, E.; Sanchez, J.; Contributors, EFDA-JET

    2005-03-01

    Real-time control of many plasma parameters will be an essential aspect in the development of reliable high performance operation of next step tokamaks. The main prerequisites for any feedback scheme are the precise real-time determination of the quantities to be controlled, requiring top quality and highly reliable diagnostics, and the availability of robust control algorithms. A new set of real-time diagnostics was recently implemented on JET to prove the feasibility of determining, with high accuracy and time resolution, the most important plasma quantities. Some of the signals now routinely provided in real time at JET are: (i) the internal inductance and the main confinement quantities obtained by calculating the Shafranov integrals from the pick-up coils with 2 ms time resolution; (ii) the electron temperature profile, from electron cylotron emission every 10 ms; (iii) the ion temperature and plasma toroidal velocity profiles, from charge exchange recombination spectroscopy, provided every 50 ms; and (iv) the safety factor profile, derived from the inversion of the polarimetric line integrals every 2 ms. With regard to feedback algorithms, new model-based controllers were developed to allow a more robust control of several plasma parameters. With these new tools, several real-time schemes were implemented, among which the most significant is the simultaneous control of the safety factor and the plasma pressure profiles using the additional heating systems (LH, NBI, ICRH) as actuators. The control strategy adopted in this case consists of a multi-variable model-based technique, which was implemented as a truncated singular value decomposition of an integral operator. This approach is considered essential for systems like tokamak machines, characterized by a strong mutual dependence of the various parameters and the distributed nature of the quantities, the plasma profiles, to be controlled. First encouraging results were also obtained using non

  5. Electric and magnetic losses modeled by a stable hybrid with explicit-implicit time-stepping for Maxwell's equations

    SciTech Connect

    Halleroed, Tomas Rylander, Thomas

    2008-04-20

    A stable hybridization of the finite-element method (FEM) and the finite-difference time-domain (FDTD) scheme for Maxwell's equations with electric and magnetic losses is presented for two-dimensional problems. The hybrid method combines the flexibility of the FEM with the efficiency of the FDTD scheme and it is based directly on Ampere's and Faraday's law. The electric and magnetic losses can be treated implicitly by the FEM on an unstructured mesh, which allows for local mesh refinement in order to resolve rapid variations in the material parameters and/or the electromagnetic field. It is also feasible to handle larger homogeneous regions with losses by the explicit FDTD scheme connected to an implicitly time-stepped and lossy FEM region. The hybrid method shows second-order convergence for smooth scatterers. The bistatic radar cross section (RCS) for a circular metal cylinder with a lossy coating converges to the analytical solution and an accuracy of 2% is achieved for about 20 points per wavelength. The monostatic RCS for an airfoil that features sharp corners yields a lower order of convergence and it is found to agree well with what can be expected for singular fields at the sharp corners. A careful convergence study with resolutions from 20 to 140 points per wavelength provides accurate extrapolated results for this non-trivial test case, which makes it possible to use as a reference problem for scattering codes that model both electric and magnetic losses.

  6. Webinar Presentation: Environmental Exposures and Health Risks in California Child Care Facilities: First Steps to Improve Environmental Health where Children Spend Time

    EPA Pesticide Factsheets

    This presentation, Environmental Exposures and Health Risks in California Child Care Facilities: First Steps to Improve Environmental Health where Children Spend Time, was given at the NIEHS/EPA Children's Centers 2016 Webinar Series: Exposome.

  7. Multiple time step molecular dynamics in the optimized isokinetic ensemble steered with the molecular theory of solvation: Accelerating with advanced extrapolation of effective solvation forces

    SciTech Connect

    Omelyan, Igor E-mail: omelyan@icmp.lviv.ua; Kovalenko, Andriy

    2013-12-28

    We develop efficient handling of solvation forces in the multiscale method of multiple time step molecular dynamics (MTS-MD) of a biomolecule steered by the solvation free energy (effective solvation forces) obtained from the 3D-RISM-KH molecular theory of solvation (three-dimensional reference interaction site model complemented with the Kovalenko-Hirata closure approximation). To reduce the computational expenses, we calculate the effective solvation forces acting on the biomolecule by using advanced solvation force extrapolation (ASFE) at inner time steps while converging the 3D-RISM-KH integral equations only at large outer time steps. The idea of ASFE consists in developing a discrete non-Eckart rotational transformation of atomic coordinates that minimizes the distances between the atomic positions of the biomolecule at different time moments. The effective solvation forces for the biomolecule in a current conformation at an inner time step are then extrapolated in the transformed subspace of those at outer time steps by using a modified least square fit approach applied to a relatively small number of the best force-coordinate pairs. The latter are selected from an extended set collecting the effective solvation forces obtained from 3D-RISM-KH at outer time steps over a broad time interval. The MTS-MD integration with effective solvation forces obtained by converging 3D-RISM-KH at outer time steps and applying ASFE at inner time steps is stabilized by employing the optimized isokinetic Nosé-Hoover chain (OIN) ensemble. Compared to the previous extrapolation schemes used in combination with the Langevin thermostat, the ASFE approach substantially improves the accuracy of evaluation of effective solvation forces and in combination with the OIN thermostat enables a dramatic increase of outer time steps. We demonstrate on a fully flexible model of alanine dipeptide in aqueous solution that the MTS-MD/OIN/ASFE/3D-RISM-KH multiscale method of molecular dynamics

  8. Multiple time step molecular dynamics in the optimized isokinetic ensemble steered with the molecular theory of solvation: Accelerating with advanced extrapolation of effective solvation forces

    NASA Astrophysics Data System (ADS)

    Omelyan, Igor; Kovalenko, Andriy

    2013-12-01

    We develop efficient handling of solvation forces in the multiscale method of multiple time step molecular dynamics (MTS-MD) of a biomolecule steered by the solvation free energy (effective solvation forces) obtained from the 3D-RISM-KH molecular theory of solvation (three-dimensional reference interaction site model complemented with the Kovalenko-Hirata closure approximation). To reduce the computational expenses, we calculate the effective solvation forces acting on the biomolecule by using advanced solvation force extrapolation (ASFE) at inner time steps while converging the 3D-RISM-KH integral equations only at large outer time steps. The idea of ASFE consists in developing a discrete non-Eckart rotational transformation of atomic coordinates that minimizes the distances between the atomic positions of the biomolecule at different time moments. The effective solvation forces for the biomolecule in a current conformation at an inner time step are then extrapolated in the transformed subspace of those at outer time steps by using a modified least square fit approach applied to a relatively small number of the best force-coordinate pairs. The latter are selected from an extended set collecting the effective solvation forces obtained from 3D-RISM-KH at outer time steps over a broad time interval. The MTS-MD integration with effective solvation forces obtained by converging 3D-RISM-KH at outer time steps and applying ASFE at inner time steps is stabilized by employing the optimized isokinetic Nosé-Hoover chain (OIN) ensemble. Compared to the previous extrapolation schemes used in combination with the Langevin thermostat, the ASFE approach substantially improves the accuracy of evaluation of effective solvation forces and in combination with the OIN thermostat enables a dramatic increase of outer time steps. We demonstrate on a fully flexible model of alanine dipeptide in aqueous solution that the MTS-MD/OIN/ASFE/3D-RISM-KH multiscale method of molecular dynamics

  9. Chiropractic Adjustment

    MedlinePlus

    ... structural alignment and improve your body's physical function. Low back pain, neck pain and headache are the most common ... treated. Chiropractic adjustment can be effective in treating low back pain, although much of the research done shows only ...

  10. Adjustment disorder

    MedlinePlus

    ... from other people Skipped heartbeats and other physical complaints Trembling or twitching To have adjustment disorder, you ... ADAM Health Solutions. About MedlinePlus Site Map FAQs Customer Support Get email updates Subscribe to RSS Follow ...

  11. Invited Commentary: Little Steps Lead to Huge Steps-It's Time to Make Physical Inactivity Our Number 1 Public Health Enemy.

    PubMed

    Church, Timothy S

    2016-11-01

    The analysis plan and article in this issue of the Journal by Evenson et al. (Am J Epidemiol 2016;184(9):621-632) is well-conceived, thoughtfully conducted, and tightly written. The authors utilized the National Health and Nutrition Examination Survey data set to examine the association between accelerometer-measured physical activity level and mortality and found that meeting the 2013 federal Physical Activity Guidelines resulted in a 35% reduction in risk of mortality. The timing of these findings could not be better, given the ubiquitous nature of personal accelerometer devices. The masses are already equipped to routinely quantify their activity, and now we have the opportunity and responsibility to provide evidenced-based, tailored physical activity goals. We have evidenced-based physical activity guidelines, mass distribution of devices to track activity, and now scientific support indicating that meeting the physical activity goal, as assessed by these devices, has substantial health benefits. All of the pieces are in place to make physical inactivity a national priority, and we now have the opportunity to positively affect the health of millions of Americans.

  12. Application of time-resolved step-scan FTIR to the photodynamics of transition metal complexes and heme proteins

    NASA Astrophysics Data System (ADS)

    Palmer, Richard A.; Plunkett, Susan E.; Dyer, R. B.; Schoonover, Jon; Meyer, Thomas J.; Chao, James L.

    1994-01-01

    Time-resolved step-scan FT-IR spectroscopy is used to monitor two distinct photo-induced processes. In the first, the third harmonic of a pulsed Nd:YAG laser (355 nm) is used to initiate a metal-to-ligand charge transfer process (MLCT) in a number of Ru(II) and/or Re(I) polypyridyl complexes. Changes in the position and shape of the vibrational signatures of (pi) -backbonding ligands such as CO and/or CN provide information about the changes in oxidation state of the metal resulting from electronic excitation. Changes in the other ligands vibrational bands indicate which is the electron acceptor (radical anion). In the second example demonstrated here, the second harmonic of the Nd:YAG laser (532 nm) pumps into the (beta) -Visible band of carbonmonoxymyoglobin (MbCO). This dissociates the Fe-CO bond of the heme prosthetic group, and the recombination process is observed as indicated by changes in the amide bands of the polypeptide chain. In both cases, these are some of the very few examples of fast (sub-microsecond(s) ) TR FT-IR in the absorbance mode.

  13. A two-step real-time PCR assay for quantitation and genotyping of human parvovirus 4.

    PubMed

    Väisänen, E; Lahtinen, A; Eis-Hübinger, A M; Lappalainen, M; Hedman, K; Söderlund-Venermo, M

    2014-01-01

    Human parvovirus 4 (PARV4) of the family Parvoviridae was discovered in a plasma sample of a patient with an undiagnosed acute infection in 2005. Currently, three PARV4 genotypes have been identified, however, with an unknown clinical significance. Interestingly, these genotypes seem to differ in epidemiology. In Northern Europe, USA and Asia, genotypes 1 and 2 have been found to occur mainly in persons with a history of injecting drug use or other parenteral exposure. In contrast, genotype 3 appears to be endemic in sub-Saharan Africa, where it infects children and adults without such risk behaviour. In this study, a novel straightforward and cost-efficient molecular assay for both quantitation and genotyping of PARV4 DNA was developed. The two-step method first applies a single-probe pan-PARV4 qPCR for screening and quantitation of this relatively rare virus, and subsequently, only the positive samples undergo a real-time PCR-based multi-probe genotyping. The new qPCR-GT method is highly sensitive and specific regardless of the genotype, and thus being suitable for studying the clinical impact and occurrence of the different PARV4 genotypes.

  14. Capacity planning for electronic waste management facilities under uncertainty: multi-objective multi-time-step model development.

    PubMed

    Poonam Khanijo Ahluwalia; Nema, Arvind K

    2011-07-01

    Selection of optimum locations for locating new facilities and decision regarding capacities at the proposed facilities is a major concern for municipal authorities/managers. The decision as to whether a single facility is preferred over multiple facilities of smaller capacities would vary with varying priorities to cost and associated risks such as environmental or health risk or risk perceived by the society. Currently management of waste streams such as that of computer waste is being done using rudimentary practices and is flourishing as an unorganized sector, mainly as backyard workshops in many cities of developing nations such as India. Uncertainty in the quantification of computer waste generation is another major concern due to the informal setup of present computer waste management scenario. Hence, there is a need to simultaneously address uncertainty in waste generation quantities while analyzing the tradeoffs between cost and associated risks. The present study aimed to address the above-mentioned issues in a multi-time-step, multi-objective decision-support model, which can address multiple objectives of cost, environmental risk, socially perceived risk and health risk, while selecting the optimum configuration of existing and proposed facilities (location and capacities).

  15. Adjustment of Adaptive Gain with Bounded Linear Stability Analysis to Improve Time-Delay Margin for Metrics-Driven Adaptive Control

    NASA Technical Reports Server (NTRS)

    Bakhtiari-Nejad, Maryam; Nguyen, Nhan T.; Krishnakumar, Kalmanje Srinvas

    2009-01-01

    This paper presents the application of Bounded Linear Stability Analysis (BLSA) method for metrics driven adaptive control. The bounded linear stability analysis method is used for analyzing stability of adaptive control models, without linearizing the adaptive laws. Metrics-driven adaptive control introduces a notion that adaptation should be driven by some stability metrics to achieve robustness. By the application of bounded linear stability analysis method the adaptive gain is adjusted during the adaptation in order to meet certain phase margin requirements. Analysis of metrics-driven adaptive control is evaluated for a linear damaged twin-engine generic transport model of aircraft. The analysis shows that the system with the adjusted adaptive gain becomes more robust to unmodeled dynamics or time delay.

  16. Next Step for STEP

    SciTech Connect

    Wood, Claire; Bremner, Brenda

    2013-08-09

    The Siletz Tribal Energy Program (STEP), housed in the Tribe’s Planning Department, will hire a data entry coordinator to collect, enter, analyze and store all the current and future energy efficiency and renewable energy data pertaining to administrative structures the tribe owns and operates and for homes in which tribal members live. The proposed data entry coordinator will conduct an energy options analysis in collaboration with the rest of the Siletz Tribal Energy Program and Planning Department staff. An energy options analysis will result in a thorough understanding of tribal energy resources and consumption, if energy efficiency and conservation measures being implemented are having the desired effect, analysis of tribal energy loads (current and future energy consumption), and evaluation of local and commercial energy supply options. A literature search will also be conducted. In order to educate additional tribal members about renewable energy, we will send four tribal members to be trained to install and maintain solar panels, solar hot water heaters, wind turbines and/or micro-hydro.

  17. Accounting for time- and space-varying changes in the gravity field to improve the network adjustment of relative-gravity data

    NASA Astrophysics Data System (ADS)

    Kennedy, Jeffrey R.; Ferré, Ty P. A.

    2016-02-01

    The relative gravimeter is the primary terrestrial instrument for measuring spatially and temporally varying gravitational fields. The background noise of the instrument-that is, non-linear drift and random tares-typically requires some form of least-squares network adjustment to integrate data collected during a campaign that may take several days to weeks. Here, we present an approach to remove the change in the observed relative-gravity differences caused by hydrologic or other transient processes during a single campaign, so that the adjusted gravity values can be referenced to a single epoch. The conceptual approach is an example of coupled hydrogeophysical inversion, by which a hydrologic model is used to inform and constrain the geophysical forward model. The hydrologic model simulates the spatial variation of the rate of change of gravity as either a linear function of distance from an infiltration source, or using a 3-D numerical groundwater model. The linear function can be included in and solved for as part of the network adjustment. Alternatively, the groundwater model is used to predict the change of gravity at each station through time, from which the accumulated gravity change is calculated and removed from the data prior to the network adjustment. Data from a field experiment conducted at an artificial-recharge facility are used to verify our approach. Maximum gravity change due to hydrology (observed using a superconducting gravimeter) during the relative-gravity field campaigns was up to 2.6 μGal d-1, each campaign was between 4 and 6 d and one month elapsed between campaigns. The maximum absolute difference in the estimated gravity change between two campaigns, two months apart, using the standard network adjustment method and the new approach, was 5.5 μGal. The maximum gravity change between the same two campaigns was 148 μGal, and spatial variation in gravity change revealed zones of preferential infiltration and areas of relatively high

  18. Accounting for time- and space-varying changes in the gravity field to improve the network adjustment of relative-gravity data

    USGS Publications Warehouse

    Kennedy, Jeffrey R.; Ferre, Ty P.A.

    2015-01-01

    The relative gravimeter is the primary terrestrial instrument for measuring spatially and temporally varying gravitational fields. The background noise of the instrument—that is, non-linear drift and random tares—typically requires some form of least-squares network adjustment to integrate data collected during a campaign that may take several days to weeks. Here, we present an approach to remove the change in the observed relative-gravity differences caused by hydrologic or other transient processes during a single campaign, so that the adjusted gravity values can be referenced to a single epoch. The conceptual approach is an example of coupled hydrogeophysical inversion, by which a hydrologic model is used to inform and constrain the geophysical forward model. The hydrologic model simulates the spatial variation of the rate of change of gravity as either a linear function of distance from an infiltration source, or using a 3-D numerical groundwater model. The linear function can be included in and solved for as part of the network adjustment. Alternatively, the groundwater model is used to predict the change of gravity at each station through time, from which the accumulated gravity change is calculated and removed from the data prior to the network adjustment. Data from a field experiment conducted at an artificial-recharge facility are used to verify our approach. Maximum gravity change due to hydrology (observed using a superconducting gravimeter) during the relative-gravity field campaigns was up to 2.6 μGal d−1, each campaign was between 4 and 6 d and one month elapsed between campaigns. The maximum absolute difference in the estimated gravity change between two campaigns, two months apart, using the standard network adjustment method and the new approach, was 5.5 μGal. The maximum gravity change between the same two campaigns was 148 μGal, and spatial variation in gravity change revealed zones of preferential infiltration and areas of relatively

  19. Remedial action and feedback processing in a time-estimation task: evidence for a role of the rostral cingulate zone in behavioral adjustments without learning.

    PubMed

    van der Veen, Frederik M; Röder, Christian H; Mies, Gabry W; van der Lugt, Aad; Smits, Marion

    2011-01-01

    The present study examined the role of the rostral cingulate zone (RCZ) in feedback processing, and especially focused on effects of modality of the feedback stimulus and remedial action. Participants performed a time-estimation task in which they had to estimate a 1-second interval. After the estimation participants received verbal (correct/false) or facial (fearful face/happy face) feedback. Percentage of positive and negative feedback was kept at 50% by dynamically adjusting the interval in which estimations were labeled correct. Contrary to predictions of the reinforcement learning theory, which predicts more RCZ activation when the outcome of behavior is worse than expected, we found that the RCZ was more active after positive feedback than after negative feedback, independent of the modality of the feedback stimulus. More in line with the suggested role of the RCZ in reinforcement learning was the finding that the RCZ was more active after negative feedback that was followed by a correct adjustment as compared to negative feedback followed by an incorrect adjustment. Both findings can be explained in terms of the RCZ being involved in facilitating remedial action as opposed to the suggested signaling function (outcome is worse than expected) proposed by the reinforcement learning theory.

  20. Simplified Two-Time Step Method for Calculating Combustion and Emission Rates of Jet-A and Methane Fuel With and Without Water Injection

    NASA Technical Reports Server (NTRS)

    Molnar, Melissa; Marek, C. John

    2005-01-01

    A simplified kinetic scheme for Jet-A, and methane fuels with water injection was developed to be used in numerical combustion codes, such as the National Combustor Code (NCC) or even simple FORTRAN codes. The two time step method is either an initial time averaged value (step one) or an instantaneous value (step two). The switch is based on the water concentration in moles/cc of 1x10(exp -20). The results presented here results in a correlation that gives the chemical kinetic time as two separate functions. This two time step method is used as opposed to a one step time averaged method previously developed to determine the chemical kinetic time with increased accuracy. The first time averaged step is used at the initial times for smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, initial water to fuel mass ratio, temperature, and pressure. The second instantaneous step, to be used with higher water concentrations, gives the chemical kinetic time as a function of instantaneous fuel and water mole concentration, pressure and temperature (T4). The simple correlations would then be compared to the turbulent mixing times to determine the limiting rates of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. Chemical kinetic time equations for fuel, carbon monoxide and NOx are obtained for Jet-A fuel and methane with and without water injection to water mass loadings of 2/1 water to fuel. A similar correlation was also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium concentrations of carbon monoxide and nitrogen oxide as functions of overall equivalence ratio, water to fuel mass ratio, pressure and temperature (T3). The temperature of the gas entering

  1. Influence of the time-step on the production of free nucleons and pions from heavy-ion collisions around 1 GeV/nucleon

    NASA Astrophysics Data System (ADS)

    Zou, LiYan; Li, Miao; Guo, ChenChen; Wang, YongJia; Li, QingFeng; Liu, Ling

    2016-12-01

    By considering different values of the time-step for the potential updates in the ultra-relativistic quantum molecular dynamics (UrQMD) model, we examine its influence on observables, such as the yield and collective flow of nucleons and pions from heavyion collisions around 1 GeV/nucleon. It is found that these observables are affected to some extent by the choice of the time-step, and the impact of the time-step on the pion-related observables is more visible than that on the nucleon-related ones. However, its effect on the π -/ π + yield ratio and elliptic flow difference between neutrons and protons, which have been taken as sensitive observables for probing the density-dependent nuclear symmetry energy at high densities, is fairly weak.

  2. New Reduced Two-Time Step Method for Calculating Combustion and Emission Rates of Jet-A and Methane Fuel With and Without Water Injection

    NASA Technical Reports Server (NTRS)

    Molnar, Melissa; Marek, C. John

    2004-01-01

    A simplified kinetic scheme for Jet-A, and methane fuels with water injection was developed to be used in numerical combustion codes, such as the National Combustor Code (NCC) or even simple FORTRAN codes that are being developed at Glenn. The two time step method is either an initial time averaged value (step one) or an instantaneous value (step two). The switch is based on the water concentration in moles/cc of 1x10(exp -20). The results presented here results in a correlation that gives the chemical kinetic time as two separate functions. This two step method is used as opposed to a one step time averaged method previously developed to determine the chemical kinetic time with increased accuracy. The first time averaged step is used at the initial times for smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, initial water to fuel mass ratio, temperature, and pressure. The second instantaneous step, to be used with higher water concentrations, gives the chemical kinetic time as a function of instantaneous fuel and water mole concentration, pressure and temperature (T4). The simple correlations would then be compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates were then used to calculate the necessary chemical kinetic times. Chemical kinetic time equations for fuel, carbon monoxide and NOx were obtained for Jet-A fuel and methane with and without water injection to water mass loadings of 2/1 water to fuel. A similar correlation was also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium concentrations of carbon monoxide and nitrogen oxide as functions of overall equivalence ratio, water to fuel mass ratio, pressure and temperature (T3

  3. Gait analysis of slope walking: a study on step length, stride width, time factors and deviation in the center of pressure.

    PubMed

    Kawamura, K; Tokuhiro, A; Takechi, H

    1991-06-01

    Determination was made of step length, stride width, time factors and deviation in the center of pressure during up- and downslope walking in 17 healthy men between the ages of 19 and 34 using a force plate. Slope inclinations were set at 3, 6, 9 and 12 degrees. At 12 degrees, walking speed, the product of step length and cadence, decreased significantly (p less than 0.01) in both up- and downslope walking. The most conspicuous phenomenon in upslope walking was in cadence. The steeper the slope, the smaller was the cadence. The most conspicuous phenomenon in downslope walking was in step length. The steeper the slope, the shorter was the step length.

  4. A high-order solver for unsteady incompressible Navier-Stokes equations using the flux reconstruction method on unstructured grids with implicit dual time stepping

    NASA Astrophysics Data System (ADS)

    Cox, Christopher; Liang, Chunlei; Plesniak, Michael W.

    2016-06-01

    We report development of a high-order compact flux reconstruction method for solving unsteady incompressible flow on unstructured grids with implicit dual time stepping. The method falls under the class of methods now referred to as flux reconstruction/correction procedure via reconstruction. The governing equations employ Chorin's classic artificial compressibility formulation with dual time stepping to solve unsteady flow problems. An implicit non-linear lower-upper symmetric Gauss-Seidel scheme with backward Euler discretization is used to efficiently march the solution in pseudo time, while a second-order backward Euler discretization is used to march in physical time. We verify and validate implementation of the high-order method coupled with our implicit time stepping scheme using both steady and unsteady incompressible flow problems. The current implicit time stepping scheme is proven effective in satisfying the divergence-free constraint on the velocity field in the artificial compressibility formulation within the context of the high-order flux reconstruction method. This compact high-order method is very suitable for parallel computing and can easily be extended to moving and deforming grids.

  5. A high-order solver for unsteady incompressible Navier-Stokes equations using the flux reconstruction method on unstructured grids with implicit dual time stepping

    NASA Astrophysics Data System (ADS)

    Cox, Christopher; Liang, Chunlei; Plesniak, Michael

    2015-11-01

    This paper reports development of a high-order compact method for solving unsteady incompressible flow on unstructured grids with implicit time stepping. The method falls under the class of methods now referred to as flux reconstruction/correction procedure via reconstruction. The governing equations employ the classical artificial compressibility treatment, where dual time stepping is needed to solve unsteady flow problems. An implicit non-linear lower-upper symmetric Gauss-Seidel scheme with backward Euler discretization is used to efficiently march the solution in pseudo time, while a second-order backward Euler discretization is used to march in physical time. We verify and validate implementation of the high-order method coupled with our implicit time-stepping scheme. Three-dimensional results computed on many processing elements will be presented. The high-order method is very suitable for parallel computing and can easily be extended to moving and deforming grids. The current implicit time stepping scheme is proven effective in satisfying the divergence-free constraint on the velocity field in the artificial compressibility formulation within the context of the high-order flux reconstruction method. Financial support provided under the GW Presidential Merit Fellowship.

  6. Revisiting the Impact of Part-Time Work on Adolescent Adjustment: Distinguishing between Selection and Socialization Using Propensity Score Matching

    ERIC Educational Resources Information Center

    Monahan, Kathryn C.; Lee, Joanna M.; Steinberg, Laurence

    2011-01-01

    The impact of part-time employment on adolescent functioning remains unclear because most studies fail to adequately control for differential selection into the workplace. The present study reanalyzes data from L. Steinberg, S. Fegley, and S. M. Dornbusch (1993) using multiple imputation, which minimizes bias in effect size estimation, and 2 types…

  7. Shaft adjuster

    DOEpatents

    Harry, H.H.

    1988-03-11

    Abstract and method for the adjustment and alignment of shafts in high power devices. A plurality of adjacent rotatable angled cylinders are positioned between a base and the shaft to be aligned which when rotated introduce an axial offset. The apparatus is electrically conductive and constructed of a structurally rigid material. The angled cylinders allow the shaft such as the center conductor in a pulse line machine to be offset in any desired alignment position within the range of the apparatus. 3 figs.

  8. Shaft adjuster

    DOEpatents

    Harry, Herbert H.

    1989-01-01

    Apparatus and method for the adjustment and alignment of shafts in high power devices. A plurality of adjacent rotatable angled cylinders are positioned between a base and the shaft to be aligned which when rotated introduce an axial offset. The apparatus is electrically conductive and constructed of a structurally rigid material. The angled cylinders allow the shaft such as the center conductor in a pulse line machine to be offset in any desired alignment position within the range of the apparatus.

  9. Interaction between Purkinje Cells and Inhibitory Interneurons May Create Adjustable Output Waveforms to Generate Timed Cerebellar Output

    PubMed Central

    Hong, Simon; Optican, Lance M.

    2008-01-01

    We develop a new model that explains how the cerebellum may generate the timing in classical delay eyeblink conditioning. Recent studies show that both Purkinje cells (PCs) and inhibitory interneurons (INs) have parallel signal processing streams with two time scales: an AMPA receptor-mediated fast process and a metabotropic glutamate receptor (mGluR)-mediated slow process. Moreover, one consistent finding is an increased excitability of PC dendrites (in Larsell's lobule HVI) in animals when they acquire the classical delay eyeblink conditioning naturally, in contrast to in vitro studies, where learning involves long-term depression (LTD). Our model proposes that the delayed response comes from the slow dynamics of mGluR-mediated IP3 activation, and the ensuing calcium concentration change, and not from LTP/LTD. The conditioned stimulus (tone), arriving on the parallel fibers, triggers this slow activation in INs and PC spines. These excitatory (from PC spines) and inhibitory (from INs) signals then interact at the PC dendrites to generate variable waveforms of PC activation. When the unconditioned stimulus (puff), arriving on the climbing fibers, is coupled frequently with this slow activation the waveform is amplified (due to an increased excitability) and leads to a timed pause in the PC population. The disinhibition of deep cerebellar nuclei by this timed pause causes the delayed conditioned response. This suggested PC-IN interaction emphasizes a richer role of the INs in learning and also conforms to the recent evidence that mGluR in the cerebellar cortex may participate in slow motor execution. We show that the suggested mechanism can endow the cerebellar cortex with the versatility to learn almost any temporal pattern, in addition to those that arise in classical conditioning. PMID:18648667

  10. A semelparous fish continues upstream migration when exposed to alarm cue, but adjusts movement speed and timing

    USGS Publications Warehouse

    Luhring, Thomas M; Meckley, Trevor D.; Johnson, Nicholas S.; Siefkes, Michael J.; Hume, John B.; Wagner, C. Michael

    2016-01-01

    Animals make trade-offs between predation risk and pursuit of opportunities such as foraging and reproduction. Trade-offs between antipredator behaviours and foraging are well suited to manipulation in laboratory and field settings and have generated a vast compendium of knowledge. However, much less is known about how animals manage trade-offs between predation risk and pursuit of reproductive opportunities in the absence of the confounding effects of foraging. In the present study, we investigated how the nonfeeding migratory life stage of sea lamprey, Petromyzon marinus, responds to odour from dead conspecifics (a cue that induces avoidance behaviours in laboratory and field studies). We released groups of PIT-tagged sea lamprey 65 m from the shore of Lake Michigan or 287 m upstream in Carp Lake River and used antennas to detect their movements in the river. As the breeding season progressed, sea lamprey initiated upstream movement earlier and were more likely to enter the river. Sea lamprey that began the night in Lake Michigan entered Carp Lake River at higher rates and accelerated upstream when exposed to high concentrations of alarm cue, consistent with animals attempting to minimize time spent in risky areas. Sea lampreys that began the night in the river delayed upstream movement when exposed to alarm cue, consistent with animals sheltering and gathering information about a source of risk. We attribute this context-specific reaction to alarm cue to differences in perceived vulnerability to predation in sheltered positions in the river versus exposed positions in the lake. Once in the river, the vast majority of sea lamprey moved upstream independent of alarm cue or Julian date. Although life-history-induced time and energy budgets place rigid constraints on the direction of migration, sea lamprey attend to predation risk by modifying movement timing and speed.

  11. The current crisis in human resources for health in Africa: the time to adjust our focus is now.

    PubMed

    Dalton, Simon C

    2014-09-01

    The challenges as we strive towards universal health coverage are many, but the need for an improved health workforce is chief among them. Unfortunately the global deficit in skilled professionals continues to increase. Nevertheless, there are potential solutions, and success stories are well documented when the approach is on system building and sustainability. As we approach 2015 and the Millennium Development Goals, we must shift our focus to a more distant time point in order to achieve the dramatic gains in global health that are possible. However, we must understand that there can be no health without a workforce.

  12. Optical monitor for real time thickness change measurements via lateral-translation induced phase-stepping interferometry

    DOEpatents

    Rushford, Michael C.

    2002-01-01

    An optical monitoring instrument monitors etch depth and etch rate for controlling a wet-etching process. The instrument provides means for viewing through the back side of a thick optic onto a nearly index-matched interface. Optical baffling and the application of a photoresist mask minimize spurious reflections to allow for monitoring with extremely weak signals. A Wollaston prism enables linear translation for phase stepping.

  13. Revisiting the impact of part-time work on adolescent adjustment: distinguishing between selection and socialization using propensity score matching.

    PubMed

    Monahan, Kathryn C; Lee, Joanna M; Steinberg, Laurence

    2011-01-01

    The impact of part-time employment on adolescent functioning remains unclear because most studies fail to adequately control for differential selection into the workplace. The present study reanalyzes data from L. Steinberg, S. Fegley, and S. M. Dornbusch (1993) using multiple imputation, which minimizes bias in effect size estimation, and 2 types of propensity score matching, to account for selection effects. In this sample (N = 1,792; Grades 10-11, M = 16.26), youth who begin working more than 20 hr per week evince declines in school engagement and increases in substance use and delinquency compared with youth who remain unemployed. Conversely, working 20 hr or less a week has negligible effects, positive or negative, on academic, psychological, or behavioral outcomes.

  14. Simplified Two-Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydorgen/Oxygen

    NASA Technical Reports Server (NTRS)

    Molnar, Melissa; Marek, C. John

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two-time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (> 1 x 10(exp -20) moles/cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T4). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/air fuel and for the H2/O2. A similar correlation is also developed using data from NASA s Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T4) as a function of overall fuel/air ratio, pressure and initial temperature (T3). High values of the regression coefficient R2 are obtained.

  15. Summary of Simplified Two Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydrogen/Oxygen

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Molnar, Melissa

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (greater than l x 10(exp -20)) moles per cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T(sub 4)). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/Air fuel and for H2/O2. A similar correlation is also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T(sub 4)) as a function of overall fuel/air ratio, pressure and initial temperature (T(sub 3)). High values of the regression coefficient R squared are obtained.

  16. Using an Adjusted Serfling Regression Model to Improve the Early Warning at the Arrival of Peak Timing of Influenza in Beijing

    PubMed Central

    Wang, Xiaoli; Wu, Shuangsheng; MacIntyre, C. Raina; Zhang, Hongbin; Shi, Weixian; Peng, Xiaomin; Duan, Wei; Yang, Peng; Zhang, Yi; Wang, Quanyi

    2015-01-01

    Serfling-type periodic regression models have been widely used to identify and analyse epidemic of influenza. In these approaches, the baseline is traditionally determined using cleaned historical non-epidemic data. However, we found that the previous exclusion of epidemic seasons was empirical, since year-year variations in the seasonal pattern of activity had been ignored. Therefore, excluding fixed ‘epidemic’ months did not seem reasonable. We made some adjustments in the rule of epidemic-period removal to avoid potentially subjective definition of the start and end of epidemic periods. We fitted the baseline iteratively. Firstly, we established a Serfling regression model based on the actual observations without any removals. After that, instead of manually excluding a predefined ‘epidemic’ period (the traditional method), we excluded observations which exceeded a calculated boundary. We then established Serfling regression once more using the cleaned data and excluded observations which exceeded a calculated boundary. We repeated this process until the R2 value stopped to increase. In addition, the definitions of the onset of influenza epidemic were heterogeneous, which might make it impossible to accurately evaluate the performance of alternative approaches. We then used this modified model to detect the peak timing of influenza instead of the onset of epidemic and compared this model with traditional Serfling models using observed weekly case counts of influenza-like illness (ILIs), in terms of sensitivity, specificity and lead time. A better performance was observed. In summary, we provide an adjusted Serfling model which may have improved performance over traditional models in early warning at arrival of peak timing of influenza. PMID:25756205

  17. Beamforming of aeroacoustic sources in the time domain: An investigation of the intermittency of the noise radiated by a forward-facing step

    NASA Astrophysics Data System (ADS)

    Fischer, J.; Valeau, V.; Brizzi, L.-E.

    2016-11-01

    The present study investigates the intermittency of the broadband aeroacoustic noise produced by a forward-facing step in a flow. The noise source is viewed as a random succession of the so-called intermittent events of short duration distributed spatially in a source region in the flow. An array processing method based on time-domain beamforming has been developed in order to track systematically the intermittent events, both in the time and space domains. Based on a simulated model of the far-field pressure field, the method is validated in terms of event detection and of performance for recovering the pressure spectrum. The method is then applied to experimental array data taken in an anechoic wind-tunnel at low Mach numbers (not exceeding 0.15) for a forward-facing step of height 30 mm. The results show that some very short intermittent events (with a mean duration of the order of 0.15 ms) can be identified from the array data. The spatial distribution of the intermittent events is found to be in agreement with the frequency domain beamform maps. The probability density functions of the events, in terms of widths and apparition times, are shown to be governed by Gamma laws and indicate random phenomena; it is observed that the statistical distributions vary with the streamwise position downstream and upstream of the step, the trends being in agreement with the source behavior as evidenced by using the frequency-domain beamforming methods. The proposed method is then shown to identify, in terms of emission time, location and temporal width, a succession of short acoustic events that participate to the broadband aeroacoustic noise produced by the step; those random events are likely to be linked to the dynamics of the flow interacting with the step.

  18. Accurate molecular dynamics and nuclear quantum effects at low cost by multiple steps in real and imaginary time: Using density functional theory to accelerate wavefunction methods

    NASA Astrophysics Data System (ADS)

    Kapil, V.; VandeVondele, J.; Ceriotti, M.

    2016-02-01

    The development and implementation of increasingly accurate methods for electronic structure calculations mean that, for many atomistic simulation problems, treating light nuclei as classical particles is now one of the most serious approximations. Even though recent developments have significantly reduced the overhead for modeling the quantum nature of the nuclei, the cost is still prohibitive when combined with advanced electronic structure methods. Here we present how multiple time step integrators can be combined with ring-polymer contraction techniques (effectively, multiple time stepping in imaginary time) to reduce virtually to zero the overhead of modelling nuclear quantum effects, while describing inter-atomic forces at high levels of electronic structure theory. This is demonstrated for a combination of MP2 and semi-local DFT applied to the Zundel cation. The approach can be seamlessly combined with other methods to reduce the computational cost of path integral calculations, such as high-order factorizations of the Boltzmann operator or generalized Langevin equation thermostats.

  19. Accurate molecular dynamics and nuclear quantum effects at low cost by multiple steps in real and imaginary time: Using density functional theory to accelerate wavefunction methods

    SciTech Connect

    Kapil, V.; Ceriotti, M.; VandeVondele, J.

    2016-02-07

    The development and implementation of increasingly accurate methods for electronic structure calculations mean that, for many atomistic simulation problems, treating light nuclei as classical particles is now one of the most serious approximations. Even though recent developments have significantly reduced the overhead for modeling the quantum nature of the nuclei, the cost is still prohibitive when combined with advanced electronic structure methods. Here we present how multiple time step integrators can be combined with ring-polymer contraction techniques (effectively, multiple time stepping in imaginary time) to reduce virtually to zero the overhead of modelling nuclear quantum effects, while describing inter-atomic forces at high levels of electronic structure theory. This is demonstrated for a combination of MP2 and semi-local DFT applied to the Zundel cation. The approach can be seamlessly combined with other methods to reduce the computational cost of path integral calculations, such as high-order factorizations of the Boltzmann operator or generalized Langevin equation thermostats.

  20. The effect of large-scale model time step and multiscale coupling frequency on cloud climatology, vertical structure, and rainfall extremes in a superparameterized GCM

    SciTech Connect

    Yu, Sungduk; Pritchard, Michael S.

    2015-12-17

    The effect of global climate model (GCM) time step—which also controls how frequently global and embedded cloud resolving scales are coupled—is examined in the Superparameterized Community Atmosphere Model ver 3.0. Systematic bias reductions of time-mean shortwave cloud forcing (~10 W/m2) and longwave cloud forcing (~5 W/m2) occur as scale coupling frequency increases, but with systematically increasing rainfall variance and extremes throughout the tropics. An overarching change in the vertical structure of deep tropical convection, favoring more bottom-heavy deep convection as a global model time step is reduced may help orchestrate these responses. The weak temperature gradient approximation is more faithfully satisfied when a high scale coupling frequency (a short global model time step) is used. These findings are distinct from the global model time step sensitivities of conventionally parameterized GCMs and have implications for understanding emergent behaviors of multiscale deep convective organization in superparameterized GCMs. Lastly, the results may also be useful for helping to tune them.

  1. The effect of large-scale model time step and multiscale coupling frequency on cloud climatology, vertical structure, and rainfall extremes in a superparameterized GCM

    DOE PAGES

    Yu, Sungduk; Pritchard, Michael S.

    2015-12-17

    The effect of global climate model (GCM) time step—which also controls how frequently global and embedded cloud resolving scales are coupled—is examined in the Superparameterized Community Atmosphere Model ver 3.0. Systematic bias reductions of time-mean shortwave cloud forcing (~10 W/m2) and longwave cloud forcing (~5 W/m2) occur as scale coupling frequency increases, but with systematically increasing rainfall variance and extremes throughout the tropics. An overarching change in the vertical structure of deep tropical convection, favoring more bottom-heavy deep convection as a global model time step is reduced may help orchestrate these responses. The weak temperature gradient approximation is more faithfullymore » satisfied when a high scale coupling frequency (a short global model time step) is used. These findings are distinct from the global model time step sensitivities of conventionally parameterized GCMs and have implications for understanding emergent behaviors of multiscale deep convective organization in superparameterized GCMs. Lastly, the results may also be useful for helping to tune them.« less

  2. Budget Report 2009: Adjustment Time

    ERIC Educational Resources Information Center

    Oder, Norman

    2009-01-01

    This article reports on a 2009 budget survey conducted by "Library Journal" in which a random sample of U.S. public libraries were surveyed via mail or fax in October 2008. Those that answered the survey projected a modest increase in budgets for 2009, just 2%, with less than a 1% increase in funds for materials, a predictable area for cuts. That…

  3. Implementation of Time-Resolved Step-Scan Fourier Transform Infrared (FT-IR) Spectroscopy Using a kHz Repetition Rate Pump Laser

    PubMed Central

    MAGANA, DONNY; PARUL, DZMITRY; DYER, R. BRIAN; SHREVE, ANDREW P.

    2011-01-01

    Time-resolved step-scan Fourier transform infrared (FT-IR) spectroscopy has been shown to be invaluable for studying excited-state structures and dynamics in both biological and inorganic systems. Despite the established utility of this method, technical challenges continue to limit the data quality and more wide ranging applications. A critical problem has been the low laser repetition rate and interferometer stepping rate (both are typically 10 Hz) used for data acquisition. Here we demonstrate significant improvement in the quality of time-resolved spectra through the use of a kHz repetition rate laser to achieve kHz excitation and data collection rates while stepping the spectrometer at 200 Hz. We have studied the metal-to-ligand charge transfer excited state of Ru(bipyridine)3Cl2 in deuterated acetonitrile to test and optimize high repetition rate data collection. Comparison of different interferometer stepping rates reveals an optimum rate of 200 Hz due to minimization of long-term baseline drift. With the improved collection efficiency and signal-to-noise ratio, better assignments of the MLCT excited-state bands can be made. Using optimized parameters, carbonmonoxy myoglobin in deuterated buffer is also studied by observing the infrared signatures of carbon monoxide photolysis upon excitation of the heme. We conclude from these studies that a substantial increase in performance of ss-FT-IR instrumentation is achieved by coupling commercial infrared benches with kHz repetition rate lasers. PMID:21513597

  4. A novel enterovirus and parechovirus multiplex one-step real-time PCR-validation and clinical experience.

    PubMed

    Nielsen, Alex Christian Yde; Böttiger, Blenda; Midgley, Sofie Elisabeth; Nielsen, Lars Peter

    2013-11-01

    As the number of new enteroviruses and human parechoviruses seems ever growing, the necessity for updated diagnostics is relevant. We have updated an enterovirus assay and combined it with a previously published assay for human parechovirus resulting in a multiplex one-step RT-PCR assay. The multiplex assay was validated by analysing the sensitivity and specificity of the assay compared to the respective monoplex assays, and a good concordance was found. Furthermore, the enterovirus assay was able to detect 42 reference strains from all 4 species, and an additional 9 genotypes during panel testing and routine usage. During 15 months of routine use, from October 2008 to December 2009, we received and analysed 2187 samples (stool samples, cerebrospinal fluids, blood samples, respiratory samples and autopsy samples) were tested, from 1546 patients and detected enteroviruses and parechoviruses in 171 (8%) and 66 (3%) of the samples, respectively. 180 of the positive samples could be genotyped by PCR and sequencing and the most common genotypes found were human parechovirus type 3, echovirus 9, enterovirus 71, Coxsackievirus A16, and echovirus 25. During 2009 in Denmark, both enterovirus and human parechovirus type 3 had a similar seasonal pattern with a peak during the summer and autumn. Human parechovirus type 3 was almost invariably found in children less than 4 months of age. In conclusion, a multiplex assay was developed allowing simultaneous detection of 2 viruses, which can cause similar clinical symptoms.

  5. Dynamical Constants and Time Universals: A First Step toward a Metrical Definition of Ordered and Abnormal Cognition

    PubMed Central

    Elliott, Mark A.; du Bois, Naomi

    2017-01-01

    From the point of view of the cognitive dynamicist the organization of brain circuitry into assemblies defined by their synchrony at particular (and precise) oscillation frequencies is important for the correct correlation of all independent cortical responses to the different aspects of a given complex thought or object. From the point of view of anyone operating complex mechanical systems, i.e., those comprising independent components that are required to interact precisely in time, it follows that the precise timing of such a system is essential – not only essential but measurable, and scalable. It must also be reliable over observations to bring about consistent behavior, whatever that behavior is. The catastrophic consequence of an absence of such precision, for instance that required to govern the interference engine in many automobiles, is indicative of how important timing is for the function of dynamical systems at all levels of operation. The dynamics and temporal considerations combined indicate that it is necessary to consider the operating characteristic of any dynamical, cognitive brain system in terms, superficially at least, of oscillation frequencies. These may, themselves, be forensic of an underlying time-related taxonomy. Currently there are only two sets of relevant and necessarily systematic observations in this field: one of these reports the precise dynamical structure of the perceptual systems engaged in dynamical binding across form and time; the second, derived both empirically from perceptual performance data, as well as obtained from theoretical models, demonstrates a timing taxonomy related to a fundamental operator referred to as the time quantum. In this contribution both sets of theory and observations are reviewed and compared for their predictive consistency. Conclusions about direct comparability are discussed for both theories of cognitive dynamics and time quantum models. Finally, a brief review of some experimental data

  6. Extended Follow-up Confirms Early Vaccine-Enhanced Risk of HIV Acquisition and Demonstrates Waning Effect Over Time Among Participants in a Randomized Trial of Recombinant Adenovirus HIV Vaccine (Step Study)

    PubMed Central

    Duerr, Ann; Huang, Yunda; Buchbinder, Susan; Coombs, Robert W.; Sanchez, Jorge; del Rio, Carlos; Casapia, Martin; Santiago, Steven; Gilbert, Peter; Corey, Lawrence; Robertson, Michael N.

    2012-01-01

    Background. The Step Study tested whether an adenovirus serotype 5 (Ad5)–vectored human immunodeficiency virus (HIV) vaccine could prevent HIV acquisition and/or reduce viral load set-point after infection. At the first interim analysis, nonefficacy criteria were met. Vaccinations were halted; participants were unblinded. In post hoc analyses, more HIV infections occurred in vaccinees vs placebo recipients in men who had Ad5-neutralizing antibodies and/or were uncircumcised. Follow-up was extended to assess relative risk of HIV acquisition in vaccinees vs placebo recipients over time. Methods. We used Cox proportional hazard models for analyses of vaccine effect on HIV acquisition and vaccine effect modifiers, and nonparametric and semiparametric methods for analysis of constancy of relative risk over time. Results. One hundred seventy-two of 1836 men were infected. The adjusted vaccinees vs placebo recipients hazard ratio (HR) for all follow-up time was 1.40 (95% confidence interval [CI], 1.03–1.92; P = .03). Vaccine effect differed by baseline Ad5 or circumcision status during first 18 months, but neither was significant for all follow-up time. The HR among uncircumcised and/or Ad5-seropositive men waned with time since vaccination. No significant vaccine-associated risk was seen among circumcised, Ad5-negative men (HR, 0.97; P = 1.0) over all follow-up time. Conclusions. The vaccine-associated risk seen in interim analysis was confirmed but waned with time from vaccination. Clinical Trials Registration. NCT00095576. PMID:22561365

  7. Rapid simultaneous detection of enterovirus and parechovirus RNAs in clinical samples by one-step real-time reverse transcription-PCR assay.

    PubMed

    Bennett, Susan; Harvala, Heli; Witteveldt, Jeroen; McWilliam Leitch, E Carol; McLeish, Nigel; Templeton, Kate; Gunson, Rory; Carman, William F; Simmonds, Peter

    2011-07-01

    Enteroviruses (EVs) are recognized as the major etiological agent in meningitis in children and young adults. The use of molecular techniques, such as PCR, has substantially improved the sensitivity of enterovirus detection compared to that of virus culture methods. PCR-based methods also can detect a much wider range of EV variants, including those within species A, as well as human parechoviruses (HPeVs) that often grow poorly in vitro and which previously have been underdiagnosed by traditional methods. To exploit these developments, we developed a real-time one-step reverse transcription-PCR (RT-PCR) for the rapid and sensitive detection of EV and HPeV in clinical specimens. Two commercially available RT-PCR kits were used (method I, Platinum one-step kit; method II, Express qPCR one-step kit) with primers and probes targeting the EV and HPeV 5'-untranslated regions (5'UTR). Amplification dynamics (threshold cycle [C(T)]values and efficiencies) of absolutely quantified full-length RNA transcripts representative of EV species A to D and HPeV were similar, demonstrating the effectiveness of both assays across the range of currently described human EV and HPeV variants. Probit analysis of multiple endpoint replicates demonstrated comparable sensitivities of the assays for EV and HPeV (method I, approximately 10 copies per reaction for both targets; method II, 20 copies per reaction). C(T) values were highly reproducible on repeat testing of positive controls within assays and between assay runs. Considering the sample turnaround time of less than 3 h, the multiplexed one-step RT-PCR method provides rapid diagnostic testing for EV and HPeV in cases of suspected central nervous system infections in a clinically relevant time frame.

  8. Using a two-step matrix solution to reduce the run time in KULL's magnetic diffusion package

    SciTech Connect

    Brunner, T A; Kolev, T V

    2010-12-17

    Recently a Resistive Magnetohydrodynamics (MHD) package has been added to the KULL code. In order to be compatible with the underlying hydrodynamics algorithm, a new sub-zonal magnetics discretization was developed that supports arbitrary polygonal and polyhedral zones. This flexibility comes at the cost of many more unknowns per zone - approximately ten times more for a hexahedral mesh. We can eliminate some (or all, depending on the dimensionality) of the extra unknowns from the global matrix during assembly by using a Schur complement approach. This trades expensive global work for cache-friendly local work, while still allowing solution for the full system. Significant improvements in the solution time are observed for several test problems.

  9. Development of a time-stepping sediment budget model for assessing land use impacts in large river basins.

    PubMed

    Wilkinson, S N; Dougall, C; Kinsey-Henderson, A E; Searle, R D; Ellis, R J; Bartley, R

    2014-01-15

    The use of river basin modelling to guide mitigation of non-point source pollution of wetlands, estuaries and coastal waters has become widespread. To assess and simulate the impacts of alternate land use or climate scenarios on river washload requires modelling techniques that represent sediment sources and transport at the time scales of system response. Building on the mean-annual SedNet model, we propose a new D-SedNet model which constructs daily budgets of fine sediment sources, transport and deposition for each link in a river network. Erosion rates (hillslope, gully and streambank erosion) and fine sediment sinks (floodplains and reservoirs) are disaggregated from mean annual rates based on daily rainfall and runoff. The model is evaluated in the Burdekin basin in tropical Australia, where policy targets have been set for reducing sediment and nutrient loads to the Great Barrier Reef (GBR) lagoon from grazing and cropping land. D-SedNet predicted annual loads with similar performance to that of a sediment rating curve calibrated to monitored suspended sediment concentrations. Relative to a 22-year reference load time series at the basin outlet derived from a dynamic general additive model based on monitoring data, D-SedNet had a median absolute error of 68% compared with 112% for the rating curve. RMS error was slightly higher for D-SedNet than for the rating curve due to large relative errors on small loads in several drought years. This accuracy is similar to existing agricultural system models used in arable or humid environments. Predicted river loads were sensitive to ground vegetation cover. We conclude that the river network sediment budget model provides some capacity for predicting load time-series independent of monitoring data in ungauged basins, and for evaluating the impact of land management on river sediment load time-series, which is challenging across large regions in data-poor environments.

  10. Timing Is Everything: A Comparative Study of the Adjustment Process of Fall and Mid-Year Community College Transfer Students at a Public Four-Year University

    ERIC Educational Resources Information Center

    Peska, Scott F.

    2009-01-01

    Many four-year institutions accept community college transfer students at mid-year (i.e., second semester) to recuperate declines in fall semester enrollments (Britt & Hirt, 1999). Students entering mid-year may face unique challenges adjusting and find that the institutional support to assist in their adjustment that is available to students…

  11. Gas flushing through hyper-acidic crater lakes: the next steps within a reframed monitoring time window

    NASA Astrophysics Data System (ADS)

    Rouwet, Dmitri

    2016-04-01

    Tracking variations in the chemical composition, water temperature and pH of brines from peak-activity crater lakes is the most obvious way to forecast phreatic activity. Volcano monitoring intrinsically implies a time window of observation that should be synchronised with the kinetics of magmatic processes, such as degassing and magma intrusion. To decipher "how much time ago" a variation in degassing regime actually occurred before eventually being detected in a crater lake is key, and depends on the lake water residence time. The above reasoning assumes that gas is preserved as anions in the lake water (SO4, Cl, F anions), in other words, that scrubbing of acid gases is complete and irreversible. Less is true. Recent work has confirmed, by direct MultiGas measurement from evaporative plumes, that even the strongest acid in liquid medium (i.e. SO2) degasses from hyper-acidic crater lakes. The less strong acid HCl has long been recognised as being more volatile than hydrophyle in extremely acidic solutions (pH near 0), through a long-term steady increase in SO4/Cl ratios in the vigorously evaporating crater lake of Poás volcano. We now know that acidic gases flush through hyper-acidic crater lake brines, but we don't know to which extend (completely or partially?), and with which speed. The chemical composition hence only reflects a transient phase of the gas flushing through the lake. In terms of volcanic surveillance this brings the advantage that the monitoring time window is definitely shorter than defined by the water chemistry, but yet, we do not know how much shorter. Empirical experiments by Capaccioni et al. (in press) have tried to tackle this kinetic problem for HCl degassing from a "lab-lake" on the short-term (2 days). With this state of the art in mind, two new monitoring strategies can be proposed to seek for precursory signals of phreatic eruptions from crater lakes: (1) Tracking variations in gas compositions, fluxes and ratios between species in

  12. Two-step Laser Time-of-Flight Mass Spectrometry to Elucidate Organic Diversity in Planetary Surface Materials.

    NASA Technical Reports Server (NTRS)

    Getty, Stephanie A.; Brinckerhoff, William B.; Cornish, Timothy; Li, Xiang; Floyd, Melissa; Arevalo, Ricardo Jr.; Cook, Jamie Elsila; Callahan, Michael P.

    2013-01-01

    Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) holds promise to be a low-mass, compact in situ analytical capability for future landed missions to planetary surfaces. The ability to analyze a solid sample for both mineralogical and preserved organic content with laser ionization could be compelling as part of a scientific mission pay-load that must be prepared for unanticipated discoveries. Targeted missions for this instrument capability include Mars, Europa, Enceladus, and small icy bodies, such as asteroids and comets.

  13. Detection of Citrus leprosis virus C using specific primers and TaqMan probe in one-step real-time reverse-transcription polymerase chain reaction assays.

    PubMed

    Choudhary, Nandlal; Wei, G; Govindarajulu, A; Roy, Avijit; Li, Wenbin; Picton, Deric D; Nakhla, M K; Levy, L; Brlansky, R H

    2015-11-01

    Citrus leprosis virus C (CiLV-C), a causal agent of the leprosis disease in citrus, is mostly present in the South and Central America and spreading toward the North America. To enable better diagnosis and inhibit the further spread of this re-emerging virus a quantitative (q) real-time reverse transcription polymerase chain reaction (qRT-PCR) assay is needed for early detection of CiLV-C when the virus is present in low titer in citrus leprosis samples. Using the genomic sequence of CiLV-C, specific primers and probe were designed and synthesized to amplify a 73 nt amplicon from the movement protein (MP) gene. A standard curve of the 73 nt amplicon MP gene was developed using known 10(10)-10(1) copies of in vitro synthesized RNA transcript to estimate the copy number of RNA transcript in the citrus leprosis samples. The one-step qRT-PCR detection assays for CiLV-C were determined to be 1000 times more sensitive when compared to the one-step conventional reverse transcription polymerase chain reaction (RT-PCR) CiLV-C detection method. To evaluate the quality of the total RNA extracts, NADH dehydrogenase gene specific primers (nad5) and probe were included in reactions as an internal control. The one-step qRT-PCR specificity was successfully validated by testing for the presence of CiLV-C in the total RNA extracts of the citrus leprosis samples collected from Belize, Costa Rica, Mexico and Panama. Implementation of the one-step qRT-PCR assays for CiLV-C diagnosis should assist regulatory agencies in surveillance activities to monitor the distribution pattern of CiLV-C in countries where it is present and to prevent further dissemination into citrus growing countries where there is no report of CiLV-C presence.

  14. Seven steps of alternating electron and proton transfer in photosystem II water oxidation traced by time-resolved photothermal beam deflection at improved sensitivity.

    PubMed

    Klauss, André; Haumann, Michael; Dau, Holger

    2015-02-12

    The intricate orchestration of electron transfer (ET) and proton transfer (PT) at the Mn4CaOn-cluster of photosystem II (PSII) is mechanistically pivotal but clearly insufficiently understood. Preparations of PSII membrane particles were investigated using a kinetically competent and sensitive method, photothermal beam deflection (PBD), to monitor apparent volume changes of the PSII protein. Driven by nanosecond laser flashes, the PSII was synchronously stepped through its water-oxidation cycle involving four (semi)stable states (S0, S1, S2, and S3) and minimally three additional transiently formed intermediates. The PBD approach was optimized as compared to our previous experiments, resulting in superior signal quality and resolution of more reaction steps. Now seven transitions were detected and attributed, according to the H/D-exchange, temperature, and pH effects on their time constants, to ET or PT events. The ET steps oxidizing the Mn4CaOn cluster in the S2 → S3 and S0 → S1 transitions, a biphasic PT prior to the O2-evolving reaction, as well as the reoxidation of the primary quinone acceptor (QA(-)) at the PSII acceptor side were detected for the first time by PBD. The associated volume changes involve (i) initial formation of charged groups resulting in contraction assignable to electrostriction, (ii) volume contraction explainable by reduced metal-ligand distances upon manganese oxidation, and (iii) charge-compensating proton removal resulting in volume expansion due to electrostriction reversal. These results support a reaction cycle of water oxidation exhibiting alternate ET and PT steps. An extended kinetic scheme for the O2-evolving S3 ⇒ S0 transition is proposed, which includes crucial structural and protonic events.

  15. Photo-activated ionic gelation of alginate hydrogel: real-time rheological monitoring of the two-step crosslinking mechanism.

    PubMed

    Higham, Alina K; Bonino, Christopher A; Raghavan, Srinivasa R; Khan, Saad A

    2014-07-21

    We examine the gelation of alginate undergoing ionic crosslinking upon ultraviolet (UV) irradiation using in situ dynamic rheology. Hydrogels are formed by combining alginate with calcium carbonate (CaCO3) particles and a photoacid generator (PAG). The PAG is photolyzed upon UV irradiation, resulting in the release of free calcium ions for ionic crosslinking. The viscous and elastic moduli during gelation are monitored as a function of the UV irradiation intensity, exposure time, alginate concentration, and the ratio between alginate and calcium carbonate. Gel time decreases as irradiation intensity increases because a larger concentration of PAG is photolyzed. Interestingly, dark curing, the continuing growth of microstructure in the absence of UV light, is observed. In some instances, the sample transitions from a solution to a gel during the dark curing phase. Additionally, when exposed to constant UV irradiation after the dark curing phase, samples reach the same plateau modulus as samples exposed to constant UV without dark curing, implying that dark curing does not affect the gelation mechanism. We believe the presence of dark curing is the result of the acidic environment persisting within the sample, allowing CaCO3 to dissociate, thereby releasing free Ca(2+) ions capable of binding with the available appropriate ionic blocks of the polymer chains. The growth of microstructure is then detected if the activation barrier has been crossed to release sufficient calcium ions. In this regard, we calculate a value of 30 J that represents the activation energy required to initiate gelation.

  16. Nucleoside uptake in macrophages from various murine strains: a short-time and a two-step stimulation model

    SciTech Connect

    Busolo, F.; Conventi, L.; Grigolon, M.; Palu, G. )

    1991-06-28

    Kinetics of (3H)-uridine uptake by murine peritoneal macrophages (pM phi) is early altered after exposure to a variety of stimuli. Alterations caused by Candida albicans, lipopolysaccharide (LPS) and recombinant interferon-gamma (rIFN-gamma) were similar in SAVO, C57BL/6, C3H/HeN and C3H/HeJ mice, and were not correlated with an activation process as shown by the amount of tumor necrosis factor-alpha (TNF-alpha) being released. Short-time exposure to all stimuli resulted in an increased nucleoside uptake by SAVO pM phi, suggesting that the tumoricidal function of this cell either depends from the type of stimulus or the time when the specific interaction with the cell receptor is taking place. Experiments with priming and triggering signals confirmed the above findings, indicating that the increase or the decrease of nucleoside uptake into the cell depends essentially on the chemical nature of the priming stimulus. The triggering stimulus, on the other hand, is only able to amplify the primary response.

  17. A high-order discontinuous Galerkin method for fluid–structure interaction with efficient implicit–explicit time stepping

    SciTech Connect

    Froehle, Bradley Persson, Per-Olof

    2014-09-01

    We present a high-order accurate scheme for coupled fluid–structure interaction problems. The fluid is discretized using a discontinuous Galerkin method on unstructured tetrahedral meshes, and the structure uses a high-order volumetric continuous Galerkin finite element method. Standard radial basis functions are used for the mesh deformation. The time integration is performed using a partitioned approach based on implicit–explicit Runge–Kutta methods. The resulting scheme fully decouples the implicit solution procedures for the fluid and the solid parts, which we perform using two separate efficient parallel solvers. We demonstrate up to fifth order accuracy in time on a non-trivial test problem, on which we also show that additional subiterations are not required. We solve a benchmark problem of a cantilever beam in a shedding flow, and show good agreement with other results in the literature. Finally, we solve for the flow around a thin membrane at a high angle of attack in both 2D and 3D, and compare with the results obtained with a rigid plate.

  18. Development and validation of one-step SYBR green real-time RT-PCR for the rapid detection of newly emerged duck Tembusu virus.

    PubMed

    Liu, Zongliang; Fu, Yuguang; Ji, Yanhong; Wei, Jianzhong; Cai, Xuepeng; Zhu, Qiyun

    2013-09-01

    Duck Tembusu virus (DTMUV) is a single-stranded positive-sense RNA virus that causes disease to emerge in duck flocks and results in huge economic losses to the duck industry. However, no vaccines and control measures are available in China to date. Development of reliable and fast detection methods is necessary to prevent and control this disease. Therefore, a one-step SYBR Green real-time reverse transcription polymerase chain reaction (RT-PCR) method is established here for DTMUV detection. The results show that the method can specifically detect DTMUV without cross-reactions with selected avian pathogens. The sensitivity of the assay was 1000 times greater than that of a conventional RT-PCR and able to test as few as 20 copies from RNA standard samples. The coefficients of variations of inter- and intra-assay values ranged from 0.09% to 0.36% and 0.1% to 0.23%, respectively. Testing 168 field samples and 96 experimentally infected samples by conventional RT-PCR and the one-step SYBR Green real-time RT-PCR, the positive rates were 35.1% and 73.8% from field samples and 30.2% and 64.6% from infected samples. The one-step SYBR Green real-time RT-PCR developed in this study was shown to be a sensitive, specific, high-throughput, cost-effective, and simple diagnostic tool for the rapid detection and epidemiological surveillance of the emerging DTMUV infection.

  19. Parametric study of grid size, time step and turbulence modeling on Navier-Stokes computations over airfoils

    NASA Technical Reports Server (NTRS)

    Rumsey, Christopher L.; Anderson, W. Kyle

    1988-01-01

    An upwind-biased implicit approximate factorization algorithm is applied to several steady and unsteady turbulent flows. The thin layer form of the compressible Navier-Stokes equation is used. Both the flux vector splitting and flux difference splitting methods are used to determine fluxes, and the results are compared. Flux difference splitting predicts results more accurately than flux vector splitting on a given mesh size, but, in its present implementation, is more severely limited by the maximum CFL number for unsteady time accurate flows. Physical aspects of the computations are also examined. An equilibrium turbulent boundary layer model computes generally better steady and unsteady results than a nonequilibrium model when there is little to no boundary layer separation. Conversely, when a significant region of separation exists, the nonequilibrium model performs in better agreement with experiment.

  20. A one-step short-time synthesis of Ag@SiO2 core-shell nanoparticles.

    PubMed

    Lismont, Marjorie; Páez, Carlos A; Dreesen, Laurent

    2015-06-01

    A performance of shell-thickness precise control in silver-silica coating core-shell nanoparticles is presented. 60nm sized citrate-stabilized silver nanoparticles are directly silica coated using a modified Stöber process. Tetraethyl orthosilicate is used as a silica precursor and ammonium hydroxide as catalyst in an alcoholic solvent to promote the seeded silica growth. By simply varying the synthesis reaction time from 4 to 60min, the silica shell thickness is increased from 5.1nm to 76.4nm. This well-controlled synthesis is then transposed to 40, 80 and 100nm sized silver cores in order to show the independence of the silica shell growth on the nanoparticle core size. Optical properties, i.e. localized surface plasmon resonance, of the produced silver-silica core-shell are also investigated.

  1. Determination of wine microbiota using classical method, polymerase chain method and Step One Real-Time PCR during fermentation process.

    PubMed

    Kačániová, Miroslava; Hleba, Lukáš; Pochop, Jaroslav; Kádasi-Horáková, Miriam; Fikselová, Martina; Rovná, Katarína

    2012-01-01

    The aim of our study was the identification of grape, must and wine microbiota during the fermentation process using a classical microbiological method and Real-Time PCR. The changes in different groups of microorganisms were monitored in total counts of bacteria, lactobacilli and yeasts. Microbiological parameters were observed during the current collection and processing of grapes in 2009. Samples were taken during the fermentation process in wine enterprises and a private vineyard. During this period 30 samples of wine among Müller Thurgau, Cabernet Sauvignon, Chardonnay, Tramin and Red Bio-wine were examined. Samples were collected from stages of grape-must unfiltered, grape-must filtered, the beginning of fermentation, fermentation, late fermentation and young wine. The highest total counts of bacteria ranged from 0.00 to 176 ± 15 CFU.mL(-1) in the wine of Müller Thurgau, the highest number of yeast ranged from 0.00 to 150 ± 9 CFU.mL(-1) in the wine of Müller Thurgau and the number of Lactobacillus spp. ranged from 0.00 to 92 ± 5 CFU.mL(-1) in the sample of Cabernet Sauvignon wine. The presence and sensitivity of Gram-positive and Gram-negative bacterial species Enterococcus faecium, Lactobacillus acidophilus, Lactobacillus crispatus and Lactobacillus salivarius were detected using Real-Time PCR (RTQ PCR). Susceptibility of Enterococcus faecium varied in different isolates from 1 to 10(6) CFU.mL(-1), the sensitivity of the species Lactobacillus acidophilus in different isolates of the wine samples ranged from 1 to 10(5) CFU.mL(-1). We also monitored representation of species Lactobacillus crispatus, which were captured by RTQ PCR sensitivity and ranged from 1 to 10(5) CFU.mL(-1). Identification of the species Lactobacillus salivarius in each of isolates by RTQ PCR method showed the presence of these bacteria in the range of 1 to 10(4) CFU.mL(-1).

  2. Detection of Langat virus by TaqMan real-time one-step qRT-PCR method

    PubMed Central

    Muhd Radzi, Siti Fatimah; Rückert, Claudia; Sam, Sing-Sin; Teoh, Boon-Teong; Jee, Pui-Fong; Phoon, Wai-Hong; Abubakar, Sazaly; Zandi, Keivan

    2015-01-01

    Langat virus (LGTV), one of the members of the tick-borne encephalitis virus (TBEV) complex, was firstly isolated from Ixodes granulatus ticks in Malaysia. However, the prevalence of LGTV in ticks in the region remains unknown. Surveillance for LGTV is therefore important and thus a tool for specific detection of LGTV is needed. In the present study, we developed a real-time quantitative reverse-transcription-polymerase chain reaction (qRT-PCR) for rapid detection of LGTV. Our findings showed that the developed qRT-PCR could detect LGTV at a titre as low as 0.1 FFU/ml. The detection limit of the qRT-PCR assay at 95% probability was 0.28 FFU/ml as determined by probit analysis (p ≤ 0.05). Besides, the designed primers and probe did not amplify ORF of the E genes for some closely related and more pathogenic viruses including TBEV, Louping ill virus, Omsk hemorrhagic fever virus (OHFV), Alkhurma virus (ALKV), Kyasanur Forest Disease virus (KFDV) and Powassan virus (POWV) which showed the acceptable specificity of the developed assay. The sensitivity of the developed method also has been confirmed by determining the LGTV in infected tick cell line as well as LGTV- spiked tick tissues. PMID:26360297

  3. Establishment of one-step SYBR green-based real time-PCR assay for rapid detection and quantification of chikungunya virus infection

    PubMed Central

    2010-01-01

    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus and one of the prevalent re-emerging arbovirus in tropical and subtropical regions of Asia, Africa, and Central and South America. It produces a spectrum of illness ranging from inapparent infection to moderate febrile illness as well as severe arthralgia or arthritis affecting multiple joints. In this study, a quantitative, one-step real-time SYBR Green-based RT-PCR system for the non-structural protein 2 (nsP2) of CHIKV that can quantify a wide range of viral RNA concentrations was developed. Comparisons between the conventional semi-quantitative RT-PCR assay, immunofluorescence detection method and the one-step SYBR Green-based RT-PCR assay in the detection of CHIKV infection revealed much rapid and increase sensitivity of the latter method. Furthermore, this newly developed assay was validated by in vitro experiments in which ribavirin, a well-known RNA virus inhibitor, showed a dose-dependent inhibition of virus replication on cells that was assessed by viral infectivity and viral RNA production. Our results demonstrate the potential of this newly developed one-step SYBR Green I-based RT-PCR assay may be a useful tool in rapid detection of CHIKV and monitoring the extent of viral replication possibly in patients' samples. PMID:20092632

  4. Establishment of one-step SYBR green-based real time-PCR assay for rapid detection and quantification of chikungunya virus infection.

    PubMed

    Ho, Phui San; Ng, Mary Mah Lee; Chu, Justin Jang Hann

    2010-01-21

    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus and one of the prevalent re-emerging arbovirus in tropical and subtropical regions of Asia, Africa, and Central and South America. It produces a spectrum of illness ranging from inapparent infection to moderate febrile illness as well as severe arthralgia or arthritis affecting multiple joints. In this study, a quantitative, one-step real-time SYBR Green-based RT-PCR system for the non-structural protein 2 (nsP2) of CHIKV that can quantify a wide range of viral RNA concentrations was developed. Comparisons between the conventional semi-quantitative RT-PCR assay, immunofluorescence detection method and the one-step SYBR Green-based RT-PCR assay in the detection of CHIKV infection revealed much rapid and increase sensitivity of the latter method. Furthermore, this newly developed assay was validated by in vitro experiments in which ribavirin, a well-known RNA virus inhibitor, showed a dose-dependent inhibition of virus replication on cells that was assessed by viral infectivity and viral RNA production. Our results demonstrate the potential of this newly developed one-step SYBR Green I-based RT-PCR assay may be a useful tool in rapid detection of CHIKV and monitoring the extent of viral replication possibly in patients' samples.

  5. A Two-Step Lyssavirus Real-Time Polymerase Chain Reaction Using Degenerate Primers with Superior Sensitivity to the Fluorescent Antigen Test

    PubMed Central

    Nazé, Florence; Francart, Aurélie; Lamoral, Sophie; De Craeye, Stéphane; Kalai, Michael

    2014-01-01

    A generic two-step lyssavirus real-time reverse transcriptase polymerase chain reaction (qRT-PCR), based on a nested PCR strategy, was validated for the detection of different lyssavirus species. Primers with 17 to 30% of degenerate bases were used in both consecutive steps. The assay could accurately detect RABV, LBV, MOKV, DUVV, EBLV-1, EBLV-2, and ABLV. In silico sequence alignment showed a functional match with the remaining lyssavirus species. The diagnostic specificity was 100% and the sensitivity proved to be superior to that of the fluorescent antigen test. The limit of detection was ≤1 50% tissue culture infectious dose. The related vesicular stomatitis virus was not recognized, confirming the selectivity for lyssaviruses. The assay was applied to follow the evolution of rabies virus infection in the brain of mice from 0 to 10 days after intranasal inoculation. The obtained RNA curve corresponded well with the curves obtained by a one-step monospecific RABV-qRT-PCR, the fluorescent antigen test, and virus titration. Despite the presence of degenerate bases, the assay proved to be highly sensitive, specific, and reproducible. PMID:24822188

  6. Linking search space structure, run-time dynamics, and problem difficulty : a step toward demystifying tabu search.

    SciTech Connect

    Whitley, L. Darrell; Howe, Adele E.; Watson, Jean-Paul

    2004-09-01

    Tabu search is one of the most effective heuristics for locating high-quality solutions to a diverse array of NP-hard combinatorial optimization problems. Despite the widespread success of tabu search, researchers have a poor understanding of many key theoretical aspects of this algorithm, including models of the high-level run-time dynamics and identification of those search space features that influence problem difficulty. We consider these questions in the context of the job-shop scheduling problem (JSP), a domain where tabu search algorithms have been shown to be remarkably effective. Previously, we demonstrated that the mean distance between random local optima and the nearest optimal solution is highly correlated with problem difficulty for a well-known tabu search algorithm for the JSP introduced by Taillard. In this paper, we discuss various shortcomings of this measure and develop a new model of problem difficulty that corrects these deficiencies. We show that Taillard's algorithm can be modeled with high fidelity as a simple variant of a straightforward random walk. The random walk model accounts for nearly all of the variability in the cost required to locate both optimal and sub-optimal solutions to random JSPs, and provides an explanation for differences in the difficulty of random versus structured JSPs. Finally, we discuss and empirically substantiate two novel predictions regarding tabu search algorithm behavior. First, the method for constructing the initial solution is highly unlikely to impact the performance of tabu search. Second, tabu tenure should be selected to be as small as possible while simultaneously avoiding search stagnation; values larger than necessary lead to significant degradations in performance.

  7. Evaluating the timing of former glacier expansions in the Tian Shan: A key step towards robust spatial correlations

    NASA Astrophysics Data System (ADS)

    Blomdin, R.; Stroeven, A. P.; Harbor, J. M.; Lifton, N. A.; Heyman, J.; Gribenski, N.; Petrakov, D. A.; Caffee, M. W.; Ivanov, M. N.; Hättestrand, C.; Rogozhina, I.; Usubaliev, R.

    2016-12-01

    The timing of past glaciation across the Tian Shan provides a proxy for past climate change in this critical area. Correlating glacial stages across the region is difficult but cosmogenic exposure ages have considerable potential. A drawback is the large observed scatter in 10Be surface exposure data. To quantify the robustness of the dating, we compile, recalculate, and perform statistical analyses on sets of 10Be surface exposure ages from 25 moraines, consisting of 114 new and previously published ages. We assess boulder age scatter by dividing boulder groups into quality classes and rejecting boulder groups of poor quality. This allows us to distinguish and correlate robustly dated glacier limits, resulting in a more conservative chronology than advanced in previous publications. Our analysis shows that only one regional glacial stage can be reliably correlated across the Tian Shan, with glacier expansions occurring between 15 and 28 ka during marine oxygen isotope stage (MIS) 2. However, there are examples of older more extensive indicators of glacial stages between MIS 3 and MIS 6. Paleoglacier extent during MIS 2 was mainly restricted to valley glaciation. Local deviations occur: in the central Kyrgyz Tian Shan paleoglaciers were more extensive and we propose that the topographic context explains this pattern. Correlation between glacial stages prior to late MIS 2 is less reliable, because of the low number of samples and/or the poor resolution of the dating. With the current resolution and spatial coverage of robustly-dated glacier limits we advise that paleoclimatic implications for the Tian Shan glacial chronology beyond MIS 2 are speculative and that continued work toward robust glacial chronologies is needed to resolve questions regarding drivers of past glaciation in the Tian Shan and Central Asia.

  8. High order finite volume methods on wavelet-adapted grids with local time-stepping on multicore architectures for the simulation of shock-bubble interactions

    NASA Astrophysics Data System (ADS)

    Hejazialhosseini, Babak; Rossinelli, Diego; Bergdorf, Michael; Koumoutsakos, Petros

    2010-11-01

    We present a space-time adaptive solver for single- and multi-phase compressible flows that couples average interpolating wavelets with high-order finite volume schemes. The solver introduces the concept of wavelet blocks, handles large jumps in resolution and employs local time-stepping for efficient time integration. We demonstrate that the inherently sequential wavelet-based adaptivity can be implemented efficiently in multicore computer architectures using task-based parallelism and introducing the concept of wavelet blocks. We validate our computational method on a number of benchmark problems and we present simulations of shock-bubble interaction at different Mach numbers, demonstrating the accuracy and computational performance of the method.

  9. Unconditionally energy stable time stepping scheme for Cahn–Morral equation: Application to multi-component spinodal decomposition and optimal space tiling

    SciTech Connect

    Tavakoli, Rouhollah

    2016-01-01

    An unconditionally energy stable time stepping scheme is introduced to solve Cahn–Morral-like equations in the present study. It is constructed based on the combination of David Eyre's time stepping scheme and Schur complement approach. Although the presented method is general and independent of the choice of homogeneous free energy density function term, logarithmic and polynomial energy functions are specifically considered in this paper. The method is applied to study the spinodal decomposition in multi-component systems and optimal space tiling problems. A penalization strategy is developed, in the case of later problem, to avoid trivial solutions. Extensive numerical experiments demonstrate the success and performance of the presented method. According to the numerical results, the method is convergent and energy stable, independent of the choice of time stepsize. Its MATLAB implementation is included in the appendix for the numerical evaluation of algorithm and reproduction of the presented results. -- Highlights: •Extension of Eyre's convex–concave splitting scheme to multiphase systems. •Efficient solution of spinodal decomposition in multi-component systems. •Efficient solution of least perimeter periodic space partitioning problem. •Developing a penalization strategy to avoid trivial solutions. •Presentation of MATLAB implementation of the introduced algorithm.

  10. Effect of occupational polychlorinated biphenyls exposure on quality-adjusted life years over time at the HELPcB surveillance program.

    PubMed

    Esser, A; Gaum, P M; Schettgen, T; Kraus, T; Gube, M; Lang, J

    2015-01-01

    HELPcB (Health Effects in High-Level Exposure to Polychlorinated Biphenyls [PCB]) is a surveillance program for former PCB-exposed workers of a capacitor recycling company and other concerned individuals. The aim of this study was to examine the influence of polychlorinated biphenyls (PCB) on the health-related quality of life (HRQL) and on quality-adjusted life years (QALY). The EQ-5D-3L questionnaire was used to determine the HRQL. After three cross-sectional examinations at intervals of 1 yr, the longitudinal development of QALY was compared by repeated-measurement analysis of covariance (ANCOVA). The cohort was split at the 95th percentile of the comparison group for each PCB congener; known confounders such as age were taken into account. A significant difference in height and development of QALY over time was shown for the higher chlorinated non-dioxin-like PCB (hcPCB) congeners. A significant between-groups effect was found on PCB 153, PCB 180, and the sum of hcPCB. It was found that QALY decreased in the high-burden group and QALY stabilized after yr 2 in the normal-burden group. Taking the dimensions of the EQ-5D into account, the between-groups effect seems to be based predominantly on the dimension anxiety. The development of the within-group effect, however, seems to be based on the dimension mobility. This study detected a significant influence of hcPCB on the development of HRQL and QALYs over time according to the level of internal PCB burden.

  11. Changes over calendar time in the risk of specific first AIDS-defining events following HIV seroconversion, adjusting for competing risks

    PubMed Central

    Babiker, Abdel; Darbyshire, Janet; Pezzotti, Patrizio; Porter, Kholoud; Rezza, Giovanni; Walker, Sarah A; Beral, Valerie; Coutinho, Roel; Del Amo, Julia; Gill, Noël; Lee, Christine; Meyer, Laurence; Tyrer, Freya; Dabis, François; Thiébaut, Rodolphe; Lawson-Aye, Sylvie; Boufassa, Faroudy; Hamouda, Osamah; Fischer, Klaus; Pezzotti, Patrizio; Touloumi, Giota; Hatzakis, Angelos; Karafoulidou, Anastasia; Katsarou, Olga; Brettle, Ray; Del Romero, Jorge; Prins, Maria; Van Benthem, Birgit; Kirk, Ole; Pederson, Court; Hernández Aguado, Idelfonso; Pérez-Hoyos, Santiago; Eskild, Anne; Bruun, Johan N; Sannes, Mette; Sabin, Caroline; Johnson, Anne M; Phillips, Andrew N; Francioli, Patrick; Vanhems, Philippe; Egger, Mathias; Rickenbach, Martin; Cooper, David; Kaldor, John; Ashton, Lesley; Vizzard, Jeanette; Muga, Roberto; Day, Nicholas E; De Angelis, Daniela

    2002-01-01

    Background Although studies have reported large reductions in the risks of AIDS and death since the introduction of potent anti-retroviral therapies, few have evaluated whether this has been similar for all AIDS-defining diseases. We wished to evaluate changes over time in the risk of specific AIDS-defining diseases, as first events, using data from individuals with known dates of HIV seroconversion. Methods Using a competing risks proportional hazards model on pooled data from 20 cohorts (CASCADE), we evaluated time from HIV seroconversion to each first AIDS-defining disease (16 groups) and to death without AIDS for four calendar periods, adjusting for exposure category, age, sex, acute infection, and stratifying by cohort. We compared results to those obtained from a cause-specific hazards model. Results Of 6941, 2021 (29%) developed AIDS and 437 (6%) died without AIDS. The risk of AIDS or death remained constant to 1996 then reduced; relative hazard = 0.89 (95% CI: 0.77–1.03); 0.90 (95% CI: 0.81–1.01); and 0.32 (95% CI: 0.28–0.37) for 1979–1990, 1991–1993, and 1997–2001, respectively, compared to 1994–1996. Significant risk reductions in 1997–2001 were observed in all but two AIDS-defining groups and death without AIDS in a competing risks model (with similar results from a cause-specific model). There was significant heterogeneity in the risk reduction across events; from 96% for cryptosporidiosis, to 17% for death without AIDS (P < 0.0001). Conclusion These findings suggest that studies reporting a stable trend for particular AIDS diseases over the period 1979–2001 may not have accounted for the competing risks among other events or lack the power to detect smaller trends. PMID:12435766

  12. An application of the time-step topological model for three-phase transformer no-load current calculation considering hysteresis

    NASA Astrophysics Data System (ADS)

    Carrander, Claes; Mousavi, Seyed Ali; Engdahl, G. öran

    2017-02-01

    In many transformer applications, it is necessary to have a core magnetization model that takes into account both magnetic and electrical effects. This becomes particularly important in three-phase transformers, where the zero-sequence impedance is generally high, and therefore affects the magnetization very strongly. In this paper, we demonstrate a time-step topological simulation method that uses a lumped-element approach to accurately model both the electrical and magnetic circuits. The simulation method is independent of the used hysteresis model. In this paper, a hysteresis model based on the first-order reversal-curve has been used.

  13. Balance control in stepping down expected and unexpected level changes.

    PubMed

    van Dieën, Jaap H; Spanjaard, Marcel; Konemann, Reinier; Bron, Lennart; Pijnappels, Mirjam

    2007-01-01

    Stepping down an elevation in ongoing gait is a common task that can cause falls when the level change is unexpected. The aim of this study was to compare expected and unexpected stepping down. We hypothesized that unexpected stepping would lead to loss of control over the movement and potentially falls due to buckling of the leading leg at landing. Ten male subjects repeatedly walked over a platform on which they stepped down an expected 10-cm height difference. In 5 out of 50 trials, the height difference was encountered unexpectedly early. Kinematics and ground reaction forces under both feet were measured during the stride in which the height difference was negotiated. Stepping down involved a substantial increase in forward horizontal and angular momenta (approximately 40 Ns and 20 N ms). In expected stepping down, step length was significantly increased (17%), which allowed control of these forward horizontal and angular momenta immediately following landing. In unexpected stepping down, the time between expected ground contact and actual ground contact (110 ms) appeared too short to substantially adjust leg movement and increase step length. Although buckling of the leg did not occur, presumably due to its more vertical orientation at landing, momentum could not be sufficiently attenuated at landing, but a fall was prevented by a rapid step of the trailing limb. The lack of control of momentum might cause a fall, when the capacity to make such a rapid step falls short, as in the elderly, or when the height difference is larger.

  14. Compact Two-step Laser Time-of-Flight Mass Spectrometer for in Situ Analyses of Aromatic Organics on Planetary Missions

    NASA Technical Reports Server (NTRS)

    Getty, Stephanie; Brickerhoff, William; Cornish, Timothy; Ecelberger, Scott; Floyd, Melissa

    2012-01-01

    RATIONALE A miniature time-of-flight mass spectrometer has been adapted to demonstrate two-step laser desorption-ionization (LOI) in a compact instrument package for enhanced organics detection. Two-step LDI decouples the desorption and ionization processes, relative to traditional laser ionization-desorption, in order to produce low-fragmentation conditions for complex organic analytes. Tuning UV ionization laser energy allowed control ofthe degree of fragmentation, which may enable better identification of constituent species. METHODS A reflectron time-of-flight mass spectrometer prototype measuring 20 cm in length was adapted to a two-laser configuration, with IR (1064 nm) desorption followed by UV (266 nm) postionization. A relatively low ion extraction voltage of 5 kV was applied at the sample inlet. Instrument capabilities and performance were demonstrated with analysis of a model polycyclic aromatic hydrocarbon, representing a class of compounds important to the fields of Earth and planetary science. RESULTS L2MS analysis of a model PAH standard, pyrene, has been demonstrated, including parent mass identification and the onset o(tunable fragmentation as a function of ionizing laser energy. Mass resolution m/llm = 380 at full width at half-maximum was achieved which is notable for gas-phase ionization of desorbed neutrals in a highly-compact mass analyzer. CONCLUSIONS Achieving two-step laser mass spectrometry (L2MS) in a highly-miniature instrument enables a powerful approach to the detection and characterization of aromatic organics in remote terrestrial and planetary applications. Tunable detection of parent and fragment ions with high mass resolution, diagnostic of molecular structure, is possible on such a compact L2MS instrument. Selectivity of L2MS against low-mass inorganic salt interferences is a key advantage when working with unprocessed, natural samples, and a mechanism for the observed selectivity is presented.

  15. Practical aspects of adjusting digital cameras.

    PubMed

    Nordberg, Joshua J; Sluder, Greenfield

    2013-01-01

    This chapter introduces the adjustment of digital camera settings using the tools found within image acquisition software and discusses measuring gray-level information such as (1) the histogram, (2) line scan, and (3) other strategies. The pixel values in an image can be measured within many image capture software programs in two ways. The first is a histogram of pixel gray values and the second is a line-scan plot across a selectable axis of the image. Understanding how to evaluate the information presented by these tools is critical to properly adjusting the camera to maximize the image contrast without losing grayscale information. This chapter discusses the 0-255 grayscale resolution of an 8-bit camera; however, the concepts are the same for cameras of any bit depth. This chapter also describes camera settings, such as exposure time, offset, and gain, and the steps for contrast stretching such as setting the exposure time, adjusting offset and gain, and camera versus image display controls.

  16. A new and inexpensive non-bit-for-bit solution reproducibility test based on time step convergence (TSC1.0)

    NASA Astrophysics Data System (ADS)

    Wan, Hui; Zhang, Kai; Rasch, Philip J.; Singh, Balwinder; Chen, Xingyuan; Edwards, Jim

    2017-02-01

    A test procedure is proposed for identifying numerically significant solution changes in evolution equations used in atmospheric models. The test issues a fail signal when any code modifications or computing environment changes lead to solution differences that exceed the known time step sensitivity of the reference model. Initial evidence is provided using the Community Atmosphere Model (CAM) version 5.3 that the proposed procedure can be used to distinguish rounding-level solution changes from impacts of compiler optimization or parameter perturbation, which are known to cause substantial differences in the simulated climate. The test is not exhaustive since it does not detect issues associated with diagnostic calculations that do not feedback to the model state variables. Nevertheless, it provides a practical and objective way to assess the significance of solution changes. The short simulation length implies low computational cost. The independence between ensemble members allows for parallel execution of all simulations, thus facilitating fast turnaround. The new method is simple to implement since it does not require any code modifications. We expect that the same methodology can be used for any geophysical model to which the concept of time step convergence is applicable.

  17. A broadly reactive one-step SYBR Green I real-time RT-PCR assay for rapid detection of murine norovirus.

    PubMed

    Hanaki, Ken-Ichi; Ike, Fumio; Kajita, Ayako; Yasuno, Wataru; Yanagiba, Misato; Goto, Motoki; Sakai, Kouji; Ami, Yasushi; Kyuwa, Shigeru

    2014-01-01

    A one-step SYBR Green I real-time RT-PCR assay was developed for the detection and quantification of a broad range of murine noroviruses (MNVs). The primer design was based on the multiple sequence alignments of 101 sequences of the open reading frame (ORF)1-ORF2 junction of MNV. The broad reactivity and quantitative capacity of the assay were validated using 7 MNV plasmids. The assay was completed within 1 h, and the reliable detection limit was 10 copies of MNV plasmid or 0.063 median tissue culture infective doses per milliliter of RAW264 cell culture-propagated viruses. The diagnostic performance of the assay was evaluated using 158 mouse fecal samples, 91 of which were confirmed to be positive. The melting curve analysis demonstrated the diversity of MNV in the samples. This is the first report of a broadly reactive one-step SYBR Green I real-time RT-PCR assay for detecting of MNVs. The rapid and sensitive performance of this assay makes it a powerful tool for diagnostic applications.

  18. Development of a one-step SYBR Green I real-time RT-PCR assay for the detection and quantitation of Araraquara and Rio Mamore hantavirus.

    PubMed

    Machado, Alex Martins; de Souza, William Marciel; de Pádua, Michelly; da Silva Rodrigues Machado, Aline Rafaela; Figueiredo, Luiz Tadeu Moraes

    2013-09-19

    Hantaviruses are members of the family Bunyaviridae and are an emerging cause of disease worldwide with high lethality in the Americas. In Brazil, the diagnosis for hantaviruses is based on immunologic techniques associated with conventional RT-PCR. A novel one-step SYBR Green real-time RT-PCR was developed for the detection and quantitation of Araraquara (ARAV) and Rio Mamore hantavirus (RIOMV). The detection limit of assay was 10 copies/μL of RNA in vitro transcribed of segment S. The specificity of assay was evaluated by melting curve analysis, which showed that the Araraquara virus amplified product generated a melt peak at 80.83 ± 0.89 °C without generating primer-dimers or non-specific products. The assay was more sensitive than conventional RT-PCR and we detected two samples undetected by conventional RT-PCR. The one-step SYBR Green real-time quantitative RT-PCR is specific, sensible and reproducible, which makes it a powerful tool in both diagnostic applications and general research of ARAV and RIOMV and possibly other Brazilian hantaviruses.

  19. A new and inexpensive non-bit-for-bit solution reproducibility test based on time step convergence (TSC1.0)

    DOE PAGES

    Wan, Hui; Zhang, Kai; Rasch, Philip J.; ...

    2017-02-03

    A test procedure is proposed for identifying numerically significant solution changes in evolution equations used in atmospheric models. The test issues a fail signal when any code modifications or computing environment changes lead to solution differences that exceed the known time step sensitivity of the reference model. Initial evidence is provided using the Community Atmosphere Model (CAM) version 5.3 that the proposed procedure can be used to distinguish rounding-level solution changes from impacts of compiler optimization or parameter perturbation, which are known to cause substantial differences in the simulated climate. The test is not exhaustive since it does not detect issues associatedmore » with diagnostic calculations that do not feedback to the model state variables. Nevertheless, it provides a practical and objective way to assess the significance of solution changes. The short simulation length implies low computational cost. The independence between ensemble members allows for parallel execution of all simulations, thus facilitating fast turnaround. The new method is simple to implement since it does not require any code modifications. We expect that the same methodology can be used for any geophysical model to which the concept of time step  convergence is applicable.« less

  20. Investigations on polyplex stability during the freezing step of lyophilization using controlled ice nucleation--the importance of residence time in the low-viscosity fluid state.

    PubMed

    Kasper, Julia C; Pikal, Michael J; Friess, Wolfgang

    2013-03-01

    The aim of the study was to comprehensively investigate the influence of the freezing step during lyophilization on the stability of gene-delivery particles in order to better understand particle stabilization during freezing. Particle size of plasmid/linear polyethylenimine (LPEI) polyplexes at two DNA concentrations and at increasing sucrose-DNA ratios was investigated separately as a function of freezing procedure, ice-nucleation temperature, residence time of the particles in a partially frozen state, or incomplete freezing. Using a numerical model, the increase in sucrose concentration and system viscosity and corresponding bimolecular reaction rates were theoretically estimated. Freezing with a temperature-hold step after ice nucleation negatively influenced particle stability. Ice-nucleation temperature had an impact only at low DNA concentrations. Particle stability was highly reduced during the early part of freezing (<-3°C), especially at low shelf-ramp rates. In this phase, bimolecular reaction rates increase greatly at still low system viscosity. Below a critical temperature (≤∼-18°C) and at high system viscosity, no further particle aggregation occurred. In conclusion, the initial sample viscosity rather than the unfrozen volume and the residence time of particles in the low-viscosity state are the predominant factors in particle stabilization, which likely apply to aggregation in any system.

  1. The global burden of injury: incidence, mortality, disability-adjusted life years and time trends from the Global Burden of Disease study 2013

    PubMed Central

    Haagsma, Juanita A; Graetz, Nicholas; Bolliger, Ian; Naghavi, Mohsen; Higashi, Hideki; Mullany, Erin C; Abera, Semaw Ferede; Abraham, Jerry Puthenpurakal; Adofo, Koranteng; Alsharif, Ubai; Ameh, Emmanuel A; Ammar, Walid; Antonio, Carl Abelardo T; Barrero, Lope H; Bekele, Tolesa; Bose, Dipan; Brazinova, Alexandra; Catalá-López, Ferrán; Dandona, Lalit; Dandona, Rakhi; Dargan, Paul I; De Leo, Diego; Degenhardt, Louisa; Derrett, Sarah; Dharmaratne, Samath D; Driscoll, Tim R; Duan, Leilei; Petrovich Ermakov, Sergey; Farzadfar, Farshad; Feigin, Valery L; Gabbe, Belinda; Gosselin, Richard A; Hafezi-Nejad, Nima; Hamadeh, Randah Ribhi; Hijar, Martha; Hu, Guoqing; Jayaraman, Sudha P; Jiang, Guohong; Khader, Yousef Saleh; Khan, Ejaz Ahmad; Krishnaswami, Sanjay; Kulkarni, Chanda; Lecky, Fiona E; Leung, Ricky; Lunevicius, Raimundas; Lyons, Ronan Anthony; Majdan, Marek; Mason-Jones, Amanda J; Matzopoulos, Richard; Meaney, Peter A; Mekonnen, Wubegzier; Miller, Ted R; Mock, Charles N; Norman, Rosana E; Polinder, Suzanne; Pourmalek, Farshad; Rahimi-Movaghar, Vafa; Refaat, Amany; Rojas-Rueda, David; Roy, Nobhojit; Schwebel, David C; Shaheen, Amira; Shahraz, Saeid; Skirbekk, Vegard; Søreide, Kjetil; Soshnikov, Sergey; Stein, Dan J; Sykes, Bryan L; Tabb, Karen M; Temesgen, Awoke Misganaw; Tenkorang, Eric Yeboah; Theadom, Alice M; Tran, Bach Xuan; Vasankari, Tommi J; Vavilala, Monica S; Vlassov, Vasiliy Victorovich; Woldeyohannes, Solomon Meseret; Yip, Paul; Yonemoto, Naohiro; Younis, Mustafa Z; Yu, Chuanhua; Murray, Christopher J L; Vos, Theo

    2016-01-01

    Background The Global Burden of Diseases (GBD), Injuries, and Risk Factors study used the disability-adjusted life year (DALY) to quantify the burden of diseases, injuries, and risk factors. This paper provides an overview of injury estimates from the 2013 update of GBD, with detailed information on incidence, mortality, DALYs and rates of change from 1990 to 2013 for 26 causes of injury, globally, by region and by country. Methods Injury mortality was estimated using the extensive GBD mortality database, corrections for ill-defined cause of death and the cause of death ensemble modelling tool. Morbidity estimation was based on inpatient and outpatient data sets, 26 cause-of-injury and 47 nature-of-injury categories, and seven follow-up studies with patient-reported long-term outcome measures. Results In 2013, 973 million (uncertainty interval (UI) 942 to 993) people sustained injuries that warranted some type of healthcare and 4.8 million (UI 4.5 to 5.1) people died from injuries. Between 1990 and 2013 the global age-standardised injury DALY rate decreased by 31% (UI 26% to 35%). The rate of decline in DALY rates was significant for 22 cause-of-injury categories, including all the major injuries. Conclusions Injuries continue to be an important cause of morbidity and mortality in the developed and developing world. The decline in rates for almost all injuries is so prominent that it warrants a general statement that the world is becoming a safer place to live in. However, the patterns vary widely by cause, age, sex, region and time and there are still large improvements that need to be made. PMID:26635210

  2. Development of a rapid detection method to detect tdh gene in Vibrio parahaemolyticus using 2-step ultrarapid real-time polymerase chain reaction.

    PubMed

    Kang, Min-Hee; Kim, Il-Wook; Lee, Dong-Woo; Yoo, Mi-Sun; Han, Sang-Hoon; Yoon, Byoung-Su

    2011-01-01

    Thermostable direct hemolysin encoded by tdh gene has been considered an important virulence factor in pathogenic Vibrio parahaemolyticus. Two-step ultrarapid real-time polymerase chain reaction (URRT PCR) with a microchip was devised to detect V. parahaemolyticus carrying tdh gene. This novel method has a 6-μL reaction volume and extremely reduces running time since one cycle can be completed in 10 s or less. Consequently, 35 cycles of URRT PCR was successfully able to detect up to 100 fg (18 copies) of genomic DNA from pathogenic V. parahaemolyticus carrying tdh gene in 6 min. These results indicate that this method is at present the most rapid detection method for tdh gene and pathogenic V. parahaemolyticus.

  3. Development of a two-step SYBR Green I based real time RT-PCR assay for detecting and quantifying peste des petits ruminants virus in clinical samples.

    PubMed

    Abera, Tsegalem; Thangavelu, Ardhanary

    2014-12-01

    A two-step SYBR Green I based real time RT-PCR targeting the matrix (M) gene of Peste des petits ruminants virus (PPRV) was developed. The specificity of the assay was assessed against viral nucleic acid extracted from a range of animal viruses of clinical and structural similarities to PPRV including canine distemper virus, measles virus, bluetongue virus and Newcastle disease virus. But none of the viruses and no template control showed an amplification signal. Sensitivity of the same assay was assessed based on plasmid DNA copy number and with respect to infectivity titre. The lower detection limit achieved was 2.88 plasmid DNA copies/μl with corresponding Ct value of 35.93. Based on tissue culture infectivity titre the lower detection limits were 0.0001TCID50/ml and 1TCID50/ml for the SYBR green I based real time RT-PCR and conventional RT-PCR, respectively. The calculated coefficient of variations values for intra- and inter-assay variability were low, ranging from 0.21% to 1.83% and 0.44% to 1.97%, respectively. The performance of newly developed assay was evaluated on a total of 36 clinical samples suspected of PPR and compared with conventional RT-PCR. The SYBR Green I based real time RT-PCR assay detected PPRV in 32 (88.8%) of clinical samples compared to 19 (52.7%) by conventional RT-PCR. Thus, the two-step SYBR Green I based real time RT-PCR assay targeting the M gene of PPRV reported in this study was highly sensitive, specific and reproducible for detection and quantitation of PPRV nucleic acids.

  4. Adjustable Induction-Heating Coil

    NASA Technical Reports Server (NTRS)

    Ellis, Rod; Bartolotta, Paul

    1990-01-01

    Improved design for induction-heating work coil facilitates optimization of heating in different metal specimens. Three segments adjusted independently to obtain desired distribution of temperature. Reduces time needed to achieve required temperature profiles.

  5. Development of novel triplex single-step real-time PCR assay for detection of Hepatitis Virus B and C simultaneously.

    PubMed

    Prakash, Shantanu; Jain, Amita; Jain, Bhawana

    2016-05-01

    Multiplex RT-PCR assays are widely used tools for detection of hepatitis viruses, but none of them provide quality check of sample. In the present study we developed a single-step triplex real-time polymerase chain reaction (PCR) assay for detection of Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) with sample quality check, by using β-actin as housekeeping gene. The primers and probes were self-designed and assay was standardized. Assay was also destined to quantitate copy numbers of HBV and HCV. This novel assay was sensitive, specific, and reproducible for detection of HBV and HCV in serum/plasma. The assay also detected all genotypes of HBV and HCV. The detection limit was 60 IU/mL for HBV and 20 IU/mL for HCV. This assay is the first assay developed on single-step platform for nucleic acid detection of HBV and HCV with an extra edge over all other assays by providing inbuilt check for quality of sample.

  6. [Prediction models for ground surface fuels moisture content of Larix gmelinii stand in Daxing'anling of China based on one-hour time step].

    PubMed

    Yu, Hong-Zhou; Sen, Jin; Di, Xue-Ying

    2013-06-01

    By using the equilibrium moisture content-time lag methods of Nelson and Simard and the meteorological element regression method, this paper studied the dynamics of the moisture content of ground surface fine dead fuels under a Larix gmelinii stand on the sunny slope in Daxing' anling with a time interval of one hour, established the corresponding prediction models, and analyzed the prediction errors under different understory densities. The results showed that the prediction methods of the fuels moisture content based on one-hour time step were applicable for the typical Larix gmelinii stand in Daxing' anling. The mean absolute error and the mean relative error of Simard method was 1.1% and 8.5%, respectively, being lower than those of Nelson method and meteorological element regression method, and close to those of similar studies. On the same slopes and slope positions, the fuel moisture content varied with different understory densities, and thus, it would be necessary to select the appropriate equilibrium moisture content model for specific regional stand and position, or establish the fuel moisture content model based on specific stand when the dynamics of fuel moisture content would be investigated with a time interval of one hour.

  7. Development of a One-Step Immunocapture Real-Time RT-PCR Assay for Detection of Tobacco Mosaic Virus in Soil

    PubMed Central

    Yang, Jin-Guang; Wang, Feng-Long; Chen, De-Xin; Shen, Li-Li; Qian, Yu-Mei; Liang, Zhi-Yong; Zhou, Wen-Chang; Yan, Tai-He

    2012-01-01

    Tobacco mosaic virus (TMV) causes significant losses in many economically important crops. Contaminated soils may play roles as reservoirs and sources of transmission for TMV. In this study we report the development of an immunocapture real-time RT-PCR (IC-real-time RT-PCR) assay for direct detection of TMV in soils without RNA isolation. A series of TMV infected leaf sap dilutions of 1:101, 1:102, 1:103, 1:104, 1:105 and 1:106 (w/v, g/mL) were added to one gram of soil. The reactivity of DAS-ELISA and conventional RT-PCR was in the range of 1:102 and 1:103 dilution in TMV-infested soils, respectively. Meanwhile, the detection limit of IC-real-time RT-PCR sensitivity was up to 1:106 dilution. However, in plant sap infected by TMV, both IC-real-time RT-PCR and real-time RT-PCR were up to 1:106 dilution, DAS-ELISA could detect at least 1:103 dilution. IC-real-time RT-PCR method can use either plant sample extracts or cultivated soils, and show higher sensitivity than RT-PCR and DAS-ELISA for detection of TMV in soils. Therefore, the proposed IC-real-time RT-PCR assay provides an alternative for quick and very sensitive detection of TMV in soils, with the advantage of not requiring a concentration or RNA purification steps while still allowing detection of TMV for disease control. PMID:23211755

  8. Ultra-fast formation control of high-order discrete-time multi-agent systems based on multi-step predictive mechanism.

    PubMed

    Zhang, Wenle; Liu, Jianchang; Wang, Honghai

    2015-09-01

    This paper deals with the ultra-fast formation control problem of high-order discrete-time multi-agent systems. Using the local neighbor-error knowledge, a novel ultra-fast protocol with multi-step predictive information and self-feedback term is proposed. The asymptotic convergence factor is improved by a power of q+1 compared to the routine protocol. To some extent, the ultra-fast algorithm overcomes the influence of communication topology to the convergence speed. Furthermore, some sufficient conditions are given herein. The ones decouple the design of the synchronizing gains from the detailed graph properties, and explicitly reveal how the agent dynamic and the communication graph jointly affect the ultra-fast formationability. Finally, some simulations are worked out to illustrate the effectiveness of our theoretical results.

  9. Nonstandard Finite Difference Schemes: Relations Between Time and Space Step-Sizes in Numerical Schemes for PDE's That Follow from Positivity Condition

    NASA Technical Reports Server (NTRS)

    Mickens, Ronald E.

    1996-01-01

    A large class of physical phenomena can be modeled by evolution and wave type Partial Differential Equations (PDE). Few of these equations have known explicit exact solutions. Finite-difference techniques are a popular method for constructing discrete representations of these equations for the purpose of numerical integration. However, the solutions to the difference equations often contain so called numerical instabilities; these are solutions to the difference equations that do not correspond to any solution of the PDE's. For explicit schemes, the elimination of this behavior requires functional relations to exist between the time and space steps-sizes. We show that such functional relations can be obtained for certain PDE's by use of a positivity condition. The PDE's studied are the Burgers, Fisher, and linearized Euler equations.

  10. A parallel numerical simulation for supersonic flows using zonal overlapped grids and local time steps for common and distributed memory multiprocessors

    SciTech Connect

    Patel, N.R.; Sturek, W.B.; Hiromoto, R.

    1989-01-01

    Parallel Navier-Stokes codes are developed to solve both two- dimensional and three-dimensional flow fields in and around ramjet and nose tip configurations. A multi-zone overlapped grid technique is used to extend an explicit finite-difference method to more complicated geometries. Parallel implementations are developed for execution on both distributed and common-memory multiprocessor architectures. For the steady-state solutions, the use of the local time-step method has the inherent advantage of reducing the communications overhead commonly incurred by parallel implementations. Computational results of the codes are given for a series of test problems. The parallel partitioning of computational zones is also discussed. 5 refs., 18 figs.

  11. A journey of a thousand miles begins with one small step - human agency, hydrological processes and time in socio-hydrology

    NASA Astrophysics Data System (ADS)

    Ertsen, M. W.; Murphy, J. T.; Purdue, L. E.; Zhu, T.

    2013-11-01

    When simulating social action in modeling efforts, as in socio-hydrology, an issue of obvious importance is how to ensure that social action by human agents is well-represented in the analysis and the model. Generally, human decision-making is either modeled on a yearly basis or lumped together as collective social structures. Both responses are problematic, as human decision making is more complex and organizations are the result of human agency and cannot be used as explanatory forces. A way out of the dilemma how to include human agency is to go to the largest societal and environmental clustering possible: society itself and climate, with time steps of years or decades. In the paper, the other way out is developed: to face human agency squarely, and direct the modeling approach to the human agency of individuals and couple this with the lowest appropriate hydrological level and time step. This approach is supported theoretically by the work of Bruno Latour, the French sociologist and philosopher. We discuss irrigation archaeology, as it is in this discipline that the issues of scale and explanatory force are well discussed. The issue is not just what scale to use: it is what scale matters. We argue that understanding the arrangements that permitted the management of irrigation over centuries, requires modeling and understanding the small-scale, day-to-day operations and personal interactions upon which they were built. This effort, however, must be informed by the longer-term dynamics as these provide the context within which human agency, is acted out.

  12. A journey of a thousand miles begins with one small step - human agency, hydrological processes and time in socio-hydrology

    NASA Astrophysics Data System (ADS)

    Ertsen, M. W.; Murphy, J. T.; Purdue, L. E.; Zhu, T.

    2014-04-01

    When simulating social action in modeling efforts, as in socio-hydrology, an issue of obvious importance is how to ensure that social action by human agents is well-represented in the analysis and the model. Generally, human decision-making is either modeled on a yearly basis or lumped together as collective social structures. Both responses are problematic, as human decision-making is more complex and organizations are the result of human agency and cannot be used as explanatory forces. A way out of the dilemma of how to include human agency is to go to the largest societal and environmental clustering possible: society itself and climate, with time steps of years or decades. In the paper, another way out is developed: to face human agency squarely, and direct the modeling approach to the agency of individuals and couple this with the lowest appropriate hydrological level and time step. This approach is supported theoretically by the work of Bruno Latour, the French sociologist and philosopher. We discuss irrigation archaeology, as it is in this discipline that the issues of scale and explanatory force are well discussed. The issue is not just what scale to use: it is what scale matters. We argue that understanding the arrangements that permitted the management of irrigation over centuries requires modeling and understanding the small-scale, day-to-day operations and personal interactions upon which they were built. This effort, however, must be informed by the longer-term dynamics, as these provide the context within which human agency is acted out.

  13. The antibiotic resistance arrow of time: efflux pump induction is a general first step in the evolution of mycobacterial drug resistance.

    PubMed

    Schmalstieg, Aurelia M; Srivastava, Shashikant; Belkaya, Serkan; Deshpande, Devyani; Meek, Claudia; Leff, Richard; van Oers, Nicolai S C; Gumbo, Tawanda

    2012-09-01

    We hypothesize that low-level efflux pump expression is the first step in the development of high-level drug resistance in mycobacteria. We performed 28-day azithromycin dose-effect and dose-scheduling studies in our hollow-fiber model of disseminated Mycobacterium avium-M. intracellulare complex. Both microbial kill and resistance emergence were most closely linked to the within-macrophage area under the concentration-time curve (AUC)/MIC ratio. Quantitative PCR revealed that subtherapeutic azithromycin exposures over 3 days led to a 56-fold increase in expression of MAV_3306, which encodes a putative ABC transporter, and MAV_1406, which encodes a putative major facilitator superfamily pump, in M. avium. By day 7, a subpopulation of M. avium with low-level resistance was encountered and exhibited the classic inverted U curve versus AUC/MIC ratios. The resistance was abolished by an efflux pump inhibitor. While the maximal microbial kill started to decrease after day 7, a population with high-level azithromycin resistance appeared at day 28. This resistance could not be reversed by efflux pump inhibitors. Orthologs of pumps encoded by MAV_3306 and MAV_1406 were identified in Mycobacterium tuberculosis, Mycobacterium leprae, Mycobacterium marinum, Mycobacterium abscessus, and Mycobacterium ulcerans. All had highly conserved protein secondary structures. We propose that induction of several efflux pumps is the first step in a general pathway to drug resistance that eventually leads to high-level chromosomal-mutation-related resistance in mycobacteria as ordered events in an "antibiotic resistance arrow of time."

  14. Using a generational time-step model to simulate dynamics of adaptation to transgenic corn and crop rotation by western corn rootworm (Coleoptera: Chrysomelidae).

    PubMed

    Crowder, D W; Onstad, D W

    2005-04-01

    We expanded a simulation model of the population dynamics and genetics of the western corn rootworm for a landscape of corn, soybean, and other crops to study the simultaneous development of resistance to both crop rotation and transgenic corn. Transgenic corn effective against corn rootworm was recently approved in 2003 and may be a very effective new technology for control of western corn rootworm in areas with or without the rotation-resistant variant. In simulations of areas with rotation-resistant populations, planting transgenic corn to only rotated cornfields was a robust strategy to prevent resistance to both traits. In these areas, planting transgenic corn to only continuous fields was not an effective strategy for preventing adaptation to crop rotation or transgenic corn. In areas without rotation-resistant phenotypes, gene expression of the allele for resistance to transgenic corn was the most important factor affecting the development of resistance to transgenic corn. If the allele for resistance to transgenic corn is recessive, resistance can be delayed longer than 15 yr, but if the resistant allele is dominant then resistance usually developed within 15 yr. In a sensitivity analysis, among the parameters investigated, initial allele frequency and density dependence were the two most important factors affecting the evolution of resistance. We compared the results of this simulation model with a more complicated model and results between the two were similar. This indicates that results from a simpler model with a generational time-step can compare favorably with a more complex model with a daily time-step.

  15. Diagnosis of Cetacean morbillivirus: A sensitive one step real time RT fast-PCR method based on SYBR(®) Green.

    PubMed

    Sacristán, Carlos; Carballo, Matilde; Muñoz, María Jesús; Bellière, Edwige Nina; Neves, Elena; Nogal, Verónica; Esperón, Fernando

    2015-12-15

    Cetacean morbillivirus (CeMV) (family Paramyxoviridae, genus Morbillivirus) is considered the most pathogenic virus of cetaceans. It was first implicated in the bottlenose dolphin (Tursiops truncatus) mass stranding episode along the Northwestern Atlantic coast in the late 1980s, and in several more recent worldwide epizootics in different Odontoceti species. This study describes a new one step real-time reverse transcription fast polymerase chain reaction (real-time RT-fast PCR) method based on SYBR(®) Green to detect a fragment of the CeMV fusion protein gene. This primer set also works for conventional RT-PCR diagnosis. This method detected and identified all three well-characterized strains of CeMV: porpoise morbillivirus (PMV), dolphin morbillivirus (DMV) and pilot whale morbillivirus (PWMV). Relative sensitivity was measured by comparing the results obtained from 10-fold dilution series of PMV and DMV positive controls and a PWMV field sample, to those obtained by the previously described conventional phosphoprotein gene based RT-PCR method. Both the conventional and real-time RT-PCR methods involving the fusion protein gene were 100- to 1000-fold more sensitive than the previously described conventional RT-PCR method.

  16. Adjustable Autonomy Testbed

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Schrenkenghost, Debra K.

    2001-01-01

    The Adjustable Autonomy Testbed (AAT) is a simulation-based testbed located in the Intelligent Systems Laboratory in the Automation, Robotics and Simulation Division at NASA Johnson Space Center. The purpose of the testbed is to support evaluation and validation of prototypes of adjustable autonomous agent software for control and fault management for complex systems. The AA T project has developed prototype adjustable autonomous agent software and human interfaces for cooperative fault management. This software builds on current autonomous agent technology by altering the architecture, components and interfaces for effective teamwork between autonomous systems and human experts. Autonomous agents include a planner, flexible executive, low level control and deductive model-based fault isolation. Adjustable autonomy is intended to increase the flexibility and effectiveness of fault management with an autonomous system. The test domain for this work is control of advanced life support systems for habitats for planetary exploration. The CONFIG hybrid discrete event simulation environment provides flexible and dynamically reconfigurable models of the behavior of components and fluids in the life support systems. Both discrete event and continuous (discrete time) simulation are supported, and flows and pressures are computed globally. This provides fast dynamic simulations of interacting hardware systems in closed loops that can be reconfigured during operations scenarios, producing complex cascading effects of operations and failures. Current object-oriented model libraries support modeling of fluid systems, and models have been developed of physico-chemical and biological subsystems for processing advanced life support gases. In FY01, water recovery system models will be developed.

  17. A time stepping coupled finite element-state space modeling environment for synchronous machine performance and design analysis in the ABC frame of reference

    NASA Astrophysics Data System (ADS)

    Deng, Fang

    This dissertation centers on the development of a modeling environment to predict the performance and operating characteristics of salient-pole synchronous generators. The model basically consists of an algorithm consisting of two sections, a time stepping two-dimensional (2D) magnetostatic field finite element (FE) computation algorithm coupled to a state-space (SS) time-domain model of the winding circuits. Hence the term time stepping Coupled Finite Element-State Space (CFE-SS) modeling environment is adopted for this approach. In the FE section, magnetic vector potential (MVP) based finite element (FE) formulations and computation of two-dimensional (2D) magnetostatic fields are used to get the magnetic field solutions throughout a machine's cross-section at a sequence (samplings) of rotor positions covering a complete (360 deg e) ac cycle. These field solutions yield the winding inductances by means of an energy and current perturbation method. The output of the FE section is the magnetic field solutions and the entire set of phase, field, damper, and sleeve winding inductance profiles versus rotor position, including all space harmonics due to rotor saliency, damper bar slotting, sleeve segmentation, stator slotting, and magnetic saturation. These inductance profiles are decomposed into their harmonic components by Fourier analysis. The magnetic field solutions and resulting winding inductances represent the key input data to the SS portion of the CFE-SS modeling environment. Laminated machine iron core loss calculations, which include the losses in the stator and rotor as well as pole face are subsequently performed using the magnetic field solution data. Conversely, the output of the SS portion is the entire set of phase, field, damper winding (circuit), and sleeve segment currents, which also include all the resulting time harmonics. These winding current results form in turn the key input data to the FE portion of the modeling environment which is

  18. Stepped nozzle

    DOEpatents

    Sutton, George P.

    1998-01-01

    An insert which allows a supersonic nozzle of a rocket propulsion system to operate at two or more different nozzle area ratios. This provides an improved vehicle flight performance or increased payload. The insert has significant advantages over existing devices for increasing nozzle area ratios. The insert is temporarily fastened by a simple retaining mechanism to the aft end of the diverging segment of the nozzle and provides for a multi-step variation of nozzle area ratio. When mounted in place, the insert provides the nozzle with a low nozzle area ratio. During flight, the retaining mechanism is released and the insert ejected thereby providing a high nozzle area ratio in the diverging nozzle segment.

  19. Stepped nozzle

    DOEpatents

    Sutton, G.P.

    1998-07-14

    An insert is described which allows a supersonic nozzle of a rocket propulsion system to operate at two or more different nozzle area ratios. This provides an improved vehicle flight performance or increased payload. The insert has significant advantages over existing devices for increasing nozzle area ratios. The insert is temporarily fastened by a simple retaining mechanism to the aft end of the diverging segment of the nozzle and provides for a multi-step variation of nozzle area ratio. When mounted in place, the insert provides the nozzle with a low nozzle area ratio. During flight, the retaining mechanism is released and the insert ejected thereby providing a high nozzle area ratio in the diverging nozzle segment. 5 figs.

  20. Novel approach for detecting prohibited species-specific central nervous system tissue contamination in meat by one-step real-time reverse transcriptase PCR.

    PubMed

    Nagarajan, M M; Longtin, D; Simard, C

    2009-05-01

    The dissemination of prohibited species-specific central nervous system (CNS) tissue contamination in meat must be tracked to mitigate human health risk associated with bovine spongiform encephalopathy. The efficiency of compliance monitoring and risk control measures taken by concerned regulatory authorities at meat production facilities to avoid such contamination depends on the ability to detect CNS tissue with a reliable and adequately sensitive quantitative method. A rapid and convenient one-step real-time quantitative reverse transcriptase PCR (qRT-PCR) assay was developed based on the absolute quantification of glial fibrillary acidic protein (GFAP) mRNA as a marker for CNS tissue contamination in meat. The GFAP RNA quantity corresponding to a percentage of CNS tissue in artificially spiked meat was determined using an appropriate in vitro transcribed target GFAP RNA as a calibration standard in the assay. The assay had a linear dynamic range of 10(2) to 10(9) copies of target RNA and was able to detect 0.01% CNS contamination in meat. Further evaluation consisted of an analysis of 272 random meat cuts from carcasses and 109 ground meat samples received from a federally inspected abattoir and two meat processing facilities, respectively, over a 5-month period. The analyzed samples were all negative for CNS tissue contamination at an arbitrarily set lower threshold of 0.025%. Overall, the newly developed one-step qRT-PCR may be useful as an objective quantitative compliance monitoring tool and for setting an acceptable low tolerance threshold for such contamination in meat.

  1. A diagnostic one-step real-time reverse transcription polymerase chain reaction method for accurate detection of influenza virus type A

    PubMed Central

    Behzadi, Mohammad Amin; Alborzi, Abdolvahab

    2016-01-01

    Introduction Influenza A is known as a public health concern worldwide. In this study, a novel one-step real-time reverse transcription polymerase chain reaction (rtRT-PCR) assay was designed and optimized for the detection of influenza A viruses. Material and methods The primers and probe were designed based on the analysis of 90 matrix nucleotide sequence data of influenza type A subtypes from the GenBank database of the National Center for Biotechnology Information (NCBI). The influenza virus A/Tehran/5652/2010 (H1N1 pdm09) was used as a reference. The rtRT-PCR assay was optimized, compared with that of the World Health Organization (WHO), and its analytical sensitivity, specificity and reproducibility were evaluated. In total, 64 nasopharyngeal swabs from patients with influenza-like illness (ILI) and 41 samples without ILI symptoms were tested for the virus, using conventional cell culture, direct immunofluorescence antibody (DFA) methods, and one-step rtRT-PCR with the designed primer set and probe and the WHO’s. Results The optimized assay results were similar to the WHO’s. The optimized assay results were similar to WHO’s, with non-significant differences for 10–103 copies of viral RNA/reaction (p > 0.05). It detected 10 copies of viral RNA/reaction with high reproducibility and no cross reactivity with other respiratory viruses. A specific cytopathic effect was observed in 6/64 (9.37%) of the ILI group using conventional culture and DFA staining methods; however, it was not seen in non-ILI. Also, the results of our assay and the WHO’s were similar to those of viral isolation and DFA staining. Conclusions Given the high specificity, sensitivity and reproducibility of this novel assay, it can serve as a reliable diagnostic tool for the detection of influenza A viruses in clinical specimens and lab experiments. PMID:27904520

  2. A One-Step Real-Time RT-PCR Assay for the Detection and Quantitation of Sugarcane Streak Mosaic Virus.

    PubMed

    Fu, Wei-Lin; Sun, Sheng-Ren; Fu, Hua-Ying; Chen, Ru-Kai; Su, Jin-Wei; Gao, San-Ji

    2015-01-01

    Sugarcane mosaic disease is caused by the Sugarcane streak mosaic virus (SCSMV; genus Poacevirus, family Potyviridae) which is common in some Asian countries. Here, we established a protocol of a one-step real-time quantitative reverse transcription PCR (real-time qRT-PCR) using the TaqMan probe for the detection of SCSMV in sugarcane. Primers and probes were designed within the conserved region of the SCSMV coat protein (CP) gene sequences. Standard single-stranded RNA (ssRNA) generated by PCR-based gene transcripts of recombinant pGEM-CP plasmid in vitro and total RNA extracted from SCSMV-infected sugarcane were used as templates of qRT-PCR. We further performed a sensitivity assay to show that the detection limit of the assay was 100 copies of ssRNA and 2 pg of total RNA with good reproducibility. The values obtained were approximately 100-fold more sensitive than those of the conventional RT-PCR. A higher incidence (68.6%) of SCSMV infection was detected by qRT-PCR than that (48.6%) with conventional RT-PCR in samples showing mosaic symptoms. SCSMV-free samples were verified by infection with Sugarcane mosaic virus (SCMV) or Sorghum mosaic virus (SrMV) or a combination of both. The developed qRT-PCR assay may become an alternative molecular tool for an economical, rapid, and efficient detection and quantification of SCSMV.

  3. Golgi-Cox Staining Step by Step

    PubMed Central

    Zaqout, Sami; Kaindl, Angela M.

    2016-01-01

    Golgi staining remains a key method to study neuronal morphology in vivo. Since most protocols delineating modifications of the original staining method lack details on critical steps, establishing this method in a laboratory can be time-consuming and frustrating. Here, we describe the Golgi-Cox staining in such detail that should turn the staining into an easily feasible method for all scientists working in the neuroscience field. PMID:27065817

  4. The Throw-and-Catch Model of Human Gait: Evidence from Coupling of Pre-Step Postural Activity and Step Location

    PubMed Central

    Bancroft, Matthew J.; Day, Brian L.

    2016-01-01

    Postural activity normally precedes the lift of a foot from the ground when taking a step, but its function is unclear. The throw-and-catch hypothesis of human gait proposes that the pre-step activity is organized to generate momentum for the body to fall ballistically along a specific trajectory during the step. The trajectory is appropriate for the stepping foot to land at its intended location while at the same time being optimally placed to catch the body and regain balance. The hypothesis therefore predicts a strong coupling between the pre-step activity and step location. Here we examine this coupling when stepping to visually-presented targets at different locations. Ten healthy, young subjects were instructed to step as accurately as possible onto targets placed in five locations that required either different step directions or different step lengths. In 75% of trials, the target location remained constant throughout the step. In the remaining 25% of trials, the intended step location was changed by making the target jump to a new location 96 ms ± 43 ms after initiation of the pre-step activity, long before foot lift. As predicted by the throw-and-catch hypothesis, when the target location remained constant, the pre-step activity led to body momentum at foot lift that was coupled to the intended step location. When the target location jumped, the pre-step activity was adjusted (median latency 223 ms) and prolonged (on average by 69 ms), which altered the body’s momentum at foot lift according to where the target had moved. We conclude that whenever possible the coupling between the pre-step activity and the step location is maintained. This provides further support for the throw-and-catch hypothesis of human gait. PMID:28066208

  5. Vibration mode shapes visualization in industrial environment by real-time time-averaged phase-stepped electronic speckle pattern interferometry at 10.6 μm and shearography at 532 nm

    NASA Astrophysics Data System (ADS)

    Languy, Fabian; Vandenrijt, Jean-François; Thizy, Cédric; Rochet, Jonathan; Loffet, Christophe; Simon, Daniel; Georges, Marc P.

    2016-12-01

    We present our investigations on two interferometric methods suitable for industrial conditions dedicated to the visualization of vibration modes of aeronautic blades. First, we consider long-wave infrared (LWIR) electronic speckle pattern interferometry (ESPI). The use of long wavelength allows measuring larger amplitudes of vibrations compared with what can be achieved with visible light. Also longer wavelengths allow lower sensitivity to external perturbations. Second, shearography at 532 nm is used as an alternative to LWIR ESPI. Both methods are used in time-averaged mode with the use of phase-stepping. This allows transforming Bessel fringes, typical to time averaging, into phase values that provide higher contrast and improve the visualization of vibration mode shapes. Laboratory experimental results with both techniques allowed comparison of techniques, leading to selection of shearography. Finally a vibration test on electrodynamic shaker is performed in an industrial environment and mode shapes are obtained with good quality by shearography.

  6. Attentional adjustment to conflict strength: evidence from the effects of manipulating flanker-target SOA on response times and prestimulus pupil size.

    PubMed

    Wendt, Mike; Kiesel, Andrea; Geringswald, Franziska; Purmann, Sascha; Fischer, Rico

    2014-01-01

    Current models of cognitive control assume gradual adjustment of processing selectivity to the strength of conflict evoked by distractor stimuli. Using a flanker task, we varied conflict strength by manipulating target and distractor onset. Replicating previous findings, flanker interference effects were larger on trials associated with advance presentation of the flankers compared to simultaneous presentation. Controlling for stimulus and response sequence effects by excluding trials with feature repetitions from stimulus administration (Experiment 1) or from the statistical analyses (Experiment 2), we found a reduction of the flanker interference effect after high-conflict predecessor trials (i.e., trials associated with advance presentation of the flankers) but not after low-conflict predecessor trials (i.e., trials associated with simultaneous presentation of target and flankers). This result supports the assumption of conflict-strength-dependent adjustment of visual attention. The selective adaptation effect after high-conflict trials was associated with an increase in prestimulus pupil diameter, possibly reflecting increased cognitive effort of focusing attention.

  7. The effect of time step, thermostat, and strain rate on ReaxFF simulations of mechanical failure in diamond, graphene, and carbon nanotube.

    PubMed

    Jensen, Benjamin D; Wise, Kristopher E; Odegard, Gregory M

    2015-08-05

    As the sophistication of reactive force fields for molecular modeling continues to increase, their use and applicability has also expanded, sometimes beyond the scope of their original development. Reax Force Field (ReaxFF), for example, was originally developed to model chemical reactions, but is a promising candidate for modeling fracture because of its ability to treat covalent bond cleavage. Performing reliable simulations of a complex process like fracture, however, requires an understanding of the effects that various modeling parameters have on the behavior of the system. This work assesses the effects of time step size, thermostat algorithm and coupling coefficient, and strain rate on the fracture behavior of three carbon-based materials: graphene, diamond, and a carbon nanotube. It is determined that the simulated stress-strain behavior is relatively independent of the thermostat algorithm, so long as coupling coefficients are kept above a certain threshold. Likewise, the stress-strain response of the materials was also independent of the strain rate, if it is kept below a maximum strain rate. Finally, the mechanical properties of the materials predicted by the Chenoweth C/H/O parameterization for ReaxFF are compared with literature values. Some deficiencies in the Chenoweth C/H/O parameterization for predicting mechanical properties of carbon materials are observed.

  8. Static and time-resolved step-scan Fourier transform infrared investigations of the photoreaction of halorhodopsin from Natronobacterium pharaonis: consequences for models of the anion translocation mechanism.

    PubMed Central

    Hackmann, C; Guijarro, J; Chizhov, I; Engelhard, M; Rödig, C; Siebert, F

    2001-01-01

    The molecular changes during the photoreaction of halorhodopsin from Natronobacterium pharaonis have been monitored by low-temperature static and by time-resolved step-scan Fourier transform infrared difference spectroscopy. In the low-temperature L spectrum anions only influence a band around 1650 cm(-1), tentatively assigned to the C=N stretch of the protonated Schiff base of L. The analysis of the time-resolved spectra allows to identify the four states: K, L(1), L(2), and O. Between L(1) and L(2), only the apoprotein undergoes alterations. The O state is characterized by an all-trans chromophore and by rather large amide I spectral changes. Because in our analysis the intermediate containing O is in equilibrium with a state indistinguishable from L(2), we are unable to identify an N-like state. At very high chloride concentrations (>5 M), we observe a branching of the photocycle from L(2) directly back to the dark state, and we provide evidence for direct back-isomerization from L(2). This branching leads to the reported reduction of transport activity at such high chloride concentrations. We interpret the L(1) to L(2) transition as an accessibility change of the anion from the extracellular to the cytosolic side, and the large amide I bands in O as an indication for opening of the cytosolic channel from the Schiff base toward the cytosolic surface and/or as indication for changes of the binding constant of the release site. PMID:11423423

  9. MCCB warm adjustment testing concept

    NASA Astrophysics Data System (ADS)

    Erdei, Z.; Horgos, M.; Grib, A.; Preradović, D. M.; Rodic, V.

    2016-08-01

    This paper presents an experimental investigation in to operating of thermal protection device behavior from an MCCB (Molded Case Circuit Breaker). One of the main functions of the circuit breaker is to assure protection for the circuits where mounted in for possible overloads of the circuit. The tripping mechanism for the overload protection is based on a bimetal movement during a specific time frame. This movement needs to be controlled and as a solution to control this movement we choose the warm adjustment concept. This concept is meant to improve process capability control and final output. The warm adjustment device design will create a unique adjustment of the bimetal position for each individual breaker, determined when the testing current will flow thru a phase which needs to trip in a certain amount of time. This time is predetermined due to scientific calculation for all standard types of amperages and complies with the IEC 60497 standard requirements.

  10. Whole genome alignment based one-step real-time RT-PCR for universal detection of avian orthoreoviruses of chicken, pheasant and turkey origins.

    PubMed

    Tang, Yi; Lu, Huaguang

    2016-04-01

    Newly emerging avian orthoreovirus (ARV) variants have been continuously detected in Pennsylvania poultry since 2011. In this paper, we report our recent diagnostic assay development of one-step real-time RT-PCR (rRT-PCR) for the rapid and universal detection of all ARVs or reference strains of chicken, pheasant and turkey origins and six σC genotypes of the newly emerging field ARV variants in Pennsylvania (PA) poultry. Primers and probes for the rRT-PCR were designed from the conserved region of the M1 genome segment 5' end based on the whole-genome alignment of various ARV strains, including six field variants or novel strains obtained in PA poultry. The detection limit of the newly developed rRT-PCR for ARV was as low as 10 copies/reaction of viral RNA, and 10(0.50)-10(0.88) tissue culture infectious dose (TCID50)/100 μL of viruses. This new rRT-PCR detected all six σC genotypes from the 66 ARV field variant strains and reference strains tested in this study. There were no cross-reactions with other avian viruses. Reproducibility of the assay was confirmed by intra- and inter-assay tests with variability from 0.12% to 2.19%. Sensitivity and specificity of this new rRT-PCR for ARV were achieved at 100% and 88%, respectively, in comparison with virus isolation as the "gold standard" in testing poultry tissue specimen.

  11. Step-changes in the physical, chemical and biological characteristics of the Gulf of Maine, as documented by the GNATS time series

    USGS Publications Warehouse

    Balch, William M.; Drapeau, D.T.; Bowler, B.C.; Huntington, Thomas G.

    2012-01-01

    We identify step-changes in the physical, chemical and biological characteristics of the Gulf of Maine (GoM) using the Gulf of Maine North Atlantic Time Series (GNATS), a series of oceanographic measurements obtained between September 1998 and December 2010 along a transect in the GoM running from Portland, ME, to Yarmouth, NS. GNATS sampled a period of extremes in precipitation and river discharge (4 of the 8 wettest years of the last century occurred between 2005 and 2010). Coincident with increased precipitation, we observed the following shifts: (1) decreased salinity and density within the surface waters of the western GoM; (2) both reduced temperature and vertical temperature gradients in the upper 50 m; (3) increased colored dissolved organic matter (CDOM) concentrations and particle scattering in the western GoM; (4) increased concentrations of nitrate and phosphate across all but the eastern GoM; (5) increased silicate, particularly in the western GoM, with a sharp increase in the ratio of silicate to dissolved inorganic nitrogen; (6) sharply decreased carbon fixation by phytoplankton; (7) moderately decreased chlorophyll, particulate organic carbon (POC) and particulate inorganic carbon (PIC) in the central GoM and (8) decreased POC- and PIC-specific growth rates. Gulf-wide anomaly analyses suggest that (1) the surface density changes were predominantly driven by temperature, (2) dissolved nutrients, as well as POC/PON, varied in Redfield ratios and (3) anomalies for salinity, density, CDOM, particle backscattering and silicate were significantly correlated with river discharge. Precipitation and river discharge appear to be playing a critical role in controlling the long-term productivity of the Gulf of Maine by supplying CDOM and detrital material, which ultimately competes with phytoplankton for light absorption.

  12. Development and Validation of a Quantitative, One-Step, Multiplex, Real-Time Reverse Transcriptase PCR Assay for Detection of Dengue and Chikungunya Viruses

    PubMed Central

    Myers, Todd; Guevara, Carolina; Jungkind, Donald; Williams, Maya; Houng, Huo-Shu

    2016-01-01

    Dengue virus (DENV) and chikungunya virus (CHIKV) are important human pathogens with common transmission vectors and similar clinical presentations. Patient care may be impacted by the misdiagnosis of DENV and CHIKV in areas where both viruses cocirculate. In this study, we have developed and validated a one-step multiplex reverse transcriptase PCR (RT-PCR) to simultaneously detect, quantify, and differentiate between four DENV serotypes (pan-DENV) and chikungunya virus. The assay uses TaqMan technology, employing two forward primers, three reverse primers, and four fluorophore-labeled probes in a single-reaction format. Coextracted and coamplified RNA was used as an internal control (IC), and in vitro-transcribed DENV and CHIKV RNAs were used to generate standard curves for absolute quantification. The diagnostic 95% limits of detection (LOD) within the linear range were 50 and 60 RNA copies/reaction for DENV (serotypes 1 to 4) and CHIKV, respectively. Our assay was able to detect 53 different strains of DENV, representing four serotypes, and six strains of CHIKV. No cross-reactivity was observed with related flaviviruses and alphaviruses, To evaluate diagnostic sensitivity and specificity, 89 clinical samples positive or negative for DENV (serotypes 1 to 4) and CHIKV by the standard virus isolation method were tested in our assay. The multiplex RT-PCR assay showed 95% sensitivity and 100% specificity for DENV and 100% sensitivity and specificity for CHIKV. With an assay turnaround time of less than 2 h, including extraction of RNA, the multiplex quantitative RT-PCR assay provides rapid diagnosis for the differential detection of two clinically indistinguishable diseases, whose geographical occurrence is increasingly overlapping. PMID:27098955

  13. Step-gradient capillary electrochromatography.

    PubMed

    Euerby, M R; Gilligan, D; Johnson, C M; Bartle, K D

    1997-10-01

    The analytical benefits of using a step-gradient in capillary electrochromatography (CEC) are demonstrated. The application of step-gradient CEC to the analysis of six diuretics of widely differing lipophilicities was evaluated and shown to result in a marked reduction in the analysis time and an improvement in the peak shape for later-eluting lipophilic components. When the step-gradient approach was performed in an automated mode, the retention time RSD for repeated injections was below 1%.

  14. Atypical anticipatory postural adjustments during gait initiation among individuals with sub-acute stroke.

    PubMed

    Rajachandrakumar, Roshanth; Fraser, Julia E; Schinkel-Ivy, Alison; Inness, Elizabeth L; Biasin, Lou; Brunton, Karen; McIlroy, William E; Mansfield, Avril

    2017-02-01

    Anticipatory postural adjustments, executed prior to gait initiation, help preserve lateral stability when stepping. Atypical patterns of anticipatory activity prior to gait initiation may occur in individuals with unilateral impairment (e.g., stroke). This study aimed to determine the prevalence, correlates, and consequences of atypical anticipatory postural adjustment patterns prior to gait initiation in a sub-acute stroke population. Forty independently-ambulatory individuals with sub-acute stroke stood on two force plates and initiated gait at a self-selected speed. Medio-lateral centre of pressure displacement was calculated and used to define anticipatory postural adjustments (shift in medio-lateral centre of pressure >10mm from baseline). Stroke severity, motor recovery, and functional balance and mobility status were also obtained. Three patterns were identified: single (typical), absent (atypical), and multiple (atypical) anticipatory postural adjustments. Thirty-five percent of trials had atypical anticipatory postural adjustments (absent and multiple). Frequency of absent anticipatory postural adjustments was negatively correlated with walking speed. Multiple anticipatory postural adjustments were more prevalent when leading with the non-paretic than the paretic limb. Trials with multiple anticipatory postural adjustments had longer duration of anticipatory postural adjustment and time to foot-off, and shorter unloading time than trials with single anticipatory postural adjustments. A high prevalence of atypical anticipatory control prior to gait initiation was found in individuals with stroke. Temporal differences were identified with multiple anticipatory postural adjustments, indicating altered gait initiation. These findings provide insight into postural control during gait initiation in individuals with sub-acute stroke, and may inform interventions to improve ambulation in this population.

  15. Problems of Adjustment to School.

    ERIC Educational Resources Information Center

    Bartolini, Leandro A.

    This paper, one of several written for a comprehensive policy study of early childhood education in Illinois, examines and summarizes the literature on the problems of young children in adjusting to starting school full-time and describes the nature and extent of their difficulties in relation to statewide educational policy. The review of studies…

  16. 49 CFR 393.53 - Automatic brake adjusters and brake adjustment indicators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... indicators. 393.53 Section 393.53 Transportation Other Regulations Relating to Transportation (Continued... brake adjustment indicators. (a) Automatic brake adjusters (hydraulic brake systems). Each commercial... vehicle at the time it was manufactured. (c) Brake adjustment indicator (air brake systems). On...

  17. Religiosity, Emotional Responses, Perceived Pressure, and Start-Time Compliance among Individuals Who Are Court Mandated to Attend 12 Step Groups

    ERIC Educational Resources Information Center

    Tyce, Sue L.

    2009-01-01

    Research findings demonstrate that effective drug treatment often involves AA's 12 Step program. However, AA's religiosity can be seen as an important, perhaps significant emotional stimulus that either hinders or complicates attendance compliance. This study examined the individual's level of religiosity as a predictor of emotional responses,…

  18. Perturbations of ground support alter posture and locomotion coupling during step initiation in Parkinson's disease.

    PubMed

    Rogers, Mark W; Hilliard, Marjorie Johnson; Martinez, Katherine M; Zhang, Yunhui; Simuni, Tanya; Mille, Marie-Laure

    2011-02-01

    During the initiation of stepping, anticipatory postural adjustments (APAs) for lateral weight transfer and propulsion normally precede the onset of locomotion. In Parkinson's disease (PD), impaired step initiation typically involves altered APA ground force production with delayed step onset and deficits in stepping performance. If, as in stance and gait, sensory information about lower limb load is important for the control of stepping, then perturbations influencing loading conditions could affect the step initiation process. This study investigated the influence of changes in lower limb loading during step initiation in patients with PD and healthy control subjects. Participants performed rapid self-triggered step initiation with the impending single stance limb positioned over a pneumatically actuated platform. In perturbation trials, the stance limb ground support surface was either moved vertically downward (DROP) or upward (ELEVATE) by 1.5 cm shortly after the onset of the APA phase. Overall, PD patients demonstrated a longer APA duration, longer time to first step onset, and slower step speed than controls. In both groups, the DROP perturbation reinforced the intended APA kinetic changes for lateral weight transfer and resulted in a significant reduction in APA duration, increase in peak amplitude, and earlier time to first step onset compared with other conditions. During ELEVATE trials that opposed the intended weight transfer forces both groups rapidly adapted their stepping to preserve standing stability by decreasing step length and duration, and increasing step height and foot placement laterally. The findings suggested that sensory information associated with limb load and/or foot pressure modulates the spatial and temporal parameters of posture and locomotion components of step initiation in interaction with a centrally generated feedforward mode of neural control. Moreover, impaired step initiation in PD may at least acutely be enhanced by

  19. Dual field-of-view step-zoom metalens.

    PubMed

    Zheng, Guoxing; Wu, Weibiao; Li, Zile; Zhang, Shuang; Mehmood, Muhammad Qasim; He, Ping'an; Li, Song

    2017-04-01

    A conventional optical zoom system is bulky, expensive, and complicated for real-time adjustment. Recent progress in metasurface research has provided a new solution to achieve innovative compact optical systems. In this Letter, we propose a highly integrated step-zoom lens with dual field of view (FOV) based on double-sided metasurfaces. With silicon nanobrick arrays of spatially varying orientations sitting on both sides of a transparent substrate, this ultrathin step-zoom metalens can be designed to focus an incident circular polarized beam with handedness-dependent FOVs without varying the focal plane, which is important for practical applications. The proposed dual FOV step-zoom metalens, with advantages such as ultracompactness, flexibility, and replicability, can find applications in fields that require ultracompact zoom imaging and beam focusing.

  20. Bio-inspired step-climbing in a hexapod robot.

    PubMed

    Chou, Ya-Cheng; Yu, Wei-Shun; Huang, Ke-Jung; Lin, Pei-Chun

    2012-09-01

    Inspired by the observation that the cockroach changes from a tripod gait to a different gait for climbing high steps, we report on the design and implementation of a novel, fully autonomous step-climbing maneuver, which enables a RHex-style hexapod robot to reliably climb a step up to 230% higher than the length of its leg. Similar to the climbing strategy most used by cockroaches, the proposed maneuver is composed of two stages. The first stage is the 'rearing stage,' inclining the body so the front side of the body is raised and it is easier for the front legs to catch the top of the step, followed by the 'rising stage,' maneuvering the body's center of mass to the top of the step. Two infrared range sensors are installed on the front of the robot to detect the presence of the step and its orientation relative to the robot's heading, so that the robot can perform automatic gait transition, from walking to step-climbing, as well as correct its initial tilt approaching posture. An inclinometer is utilized to measure body inclination and to compute step height, thus enabling the robot to adjust its gait automatically, in real time, and to climb steps of different heights and depths successfully. The algorithm is applicable for the robot to climb various rectangular obstacles, including a narrow bar, a bar and a step (i.e. a bar of infinite width). The performance of the algorithm is evaluated experimentally, and the comparison of climbing strategies and climbing behaviors in biological and robotic systems is discussed.

  1. Knee trembling during freezing of gait represents multiple anticipatory postural adjustments.

    PubMed

    Jacobs, Jesse V; Nutt, John G; Carlson-Kuhta, Patricia; Stephens, Marilee; Horak, Fay B

    2009-02-01

    Freezing of gait (FoG) is an episodic, brief inability to step that delays gait initiation or interrupts ongoing gait. FoG is often associated with an alternating shaking of the knees, clinically referred to as knee trembling or trembling in place. The pathophysiology of FoG and of the concomitant trembling knees is unknown; impaired postural adjustment in preparation for stepping is one hypothesis. We examined anticipatory postural adjustments (APAs) prior to protective steps induced by a forward loss of balance in 10 Parkinson's disease (PD) subjects with marked FoG and in 10 control subjects. The amplitude and timing of the APAs were determined from changes in the vertical ground-reaction forces recorded by a force plate under each foot and were confirmed by electromyographic recordings of bilateral medial gastrocnemius, tibialis anterior and tensor fascia latae muscles. Protective steps were accomplished with a single APA followed by a step for control subjects, whereas PD subjects frequently exhibited multiple, alternating APAs coexistent with the knee trembling commonly observed during FoG as well as delayed, inadequate or no stepping. These multiple APAs were not delayed in onset and were of similar or larger amplitude than the single APAs exhibited by the control subjects. These observations suggest that multiple APAs produce the knee trembling commonly associated with FoG and that FoG associated with a forward loss of balance is caused by an inability to couple a normal APA to the stepping motor pattern.

  2. Micromachine Wedge Stepping Motor

    SciTech Connect

    Allen, J.J.; Schriner, H.K.

    1998-11-04

    A wedge stepping motor, which will index a mechanism, has been designed and fabricated in the surface rnicromachine SUMMiT process. This device has demonstrated the ability to index one gear tooth at a time with speeds up to 205 teeth/see. The wedge stepper motor has the following features, whi:h will be useful in a number of applications. o The ability to precisely position mechanical components. . Simple pulse signals can be used for operation. o Only 2 drive signals are requixed for operation. o Torque and precision capabilities increase with device size . The device to be indexed is restrained at all times by the wedge shaped tooth that is used for actuation. This paper will discuss the theory of operation and desi=m of the wedge stepping motor. The fabrication and testing of I he device will also be presented.

  3. The effect of adjusting model inputs to achieve mass balance on time-dynamic simulations in a food-web model of Lake Huron

    USGS Publications Warehouse

    Langseth, Brian J.; Jones, Michael L.; Riley, Stephen C.

    2014-01-01

    Ecopath with Ecosim (EwE) is a widely used modeling tool in fishery research and management. Ecopath requires a mass-balanced snapshot of a food web at a particular point in time, which Ecosim then uses to simulate changes in biomass over time. Initial inputs to Ecopath, including estimates for biomasses, production to biomass ratios, consumption to biomass ratios, and diets, rarely produce mass balance, and thus ad hoc changes to inputs are required to balance the model. There has been little previous research of whether ad hoc changes to achieve mass balance affect Ecosim simulations. We constructed an EwE model for the offshore community of Lake Huron, and balanced the model using four contrasting but realistic methods. The four balancing methods were based on two contrasting approaches; in the first approach, production of unbalanced groups was increased by increasing either biomass or the production to biomass ratio, while in the second approach, consumption of predators on unbalanced groups was decreased by decreasing either biomass or the consumption to biomass ratio. We compared six simulation scenarios based on three alternative assumptions about the extent to which mortality rates of prey can change in response to changes in predator biomass (i.e., vulnerabilities) under perturbations to either fishing mortality or environmental production. Changes in simulated biomass values over time were used in a principal components analysis to assess the comparative effect of balancing method, vulnerabilities, and perturbation types. Vulnerabilities explained the most variation in biomass, followed by the type of perturbation. Choice of balancing method explained little of the overall variation in biomass. Under scenarios where changes in predator biomass caused large changes in mortality rates of prey (i.e., high vulnerabilities), variation in biomass was greater than when changes in predator biomass caused only small changes in mortality rates of prey (i.e., low

  4. A Compact Tandem Two-Step Laser Time-of-Flight Mass Spectrometer for In Situ Analysis of Non-Volatile Organics on Planetary Surfaces

    NASA Technical Reports Server (NTRS)

    Getty, Stephanie A.; Brinckerhoff, William B.; Li, Xiang; Elsila, Jamie; Cornish, Timothy; Ecelberger, Scott; Wu, Qinghao; Zare, Richard

    2014-01-01

    Two-step laser desorption mass spectrometry is a well suited technique to the analysis of high priority classes of organics, such as polycyclic aromatic hydrocarbons, present in complex samples. The use of decoupled desorption and ionization laser pulses allows for sensitive and selective detection of structurally intact organic species. We have recently demonstrated the implementation of this advancement in laser mass spectrometry in a compact, flight-compatible instrument that could feasibly be the centerpiece of an analytical science payload as part of a future spaceflight mission to a small body or icy moon.

  5. Remotely Adjustable Hydraulic Pump

    NASA Technical Reports Server (NTRS)

    Kouns, H. H.; Gardner, L. D.

    1987-01-01

    Outlet pressure adjusted to match varying loads. Electrohydraulic servo has positioned sleeve in leftmost position, adjusting outlet pressure to maximum value. Sleeve in equilibrium position, with control land covering control port. For lowest pressure setting, sleeve shifted toward right by increased pressure on sleeve shoulder from servovalve. Pump used in aircraft and robots, where hydraulic actuators repeatedly turned on and off, changing pump load frequently and over wide range.

  6. Adjustable Pitot Probe

    NASA Technical Reports Server (NTRS)

    Ashby, George C., Jr.; Robbins, W. Eugene; Horsley, Lewis A.

    1991-01-01

    Probe readily positionable in core of uniform flow in hypersonic wind tunnel. Formed of pair of mating cylindrical housings: transducer housing and pitot-tube housing. Pitot tube supported by adjustable wedge fairing attached to top of pitot-tube housing with semicircular foot. Probe adjusted both radially and circumferentially. In addition, pressure-sensing transducer cooled internally by water or other cooling fluid passing through annulus of cooling system.

  7. Weighted triangulation adjustment

    USGS Publications Warehouse

    Anderson, Walter L.

    1969-01-01

    The variation of coordinates method is employed to perform a weighted least squares adjustment of horizontal survey networks. Geodetic coordinates are required for each fixed and adjustable station. A preliminary inverse geodetic position computation is made for each observed line. Weights associated with each observed equation for direction, azimuth, and distance are applied in the formation of the normal equations in-the least squares adjustment. The number of normal equations that may be solved is twice the number of new stations and less than 150. When the normal equations are solved, shifts are produced at adjustable stations. Previously computed correction factors are applied to the shifts and a most probable geodetic position is found for each adjustable station. Pinal azimuths and distances are computed. These may be written onto magnetic tape for subsequent computation of state plane or grid coordinates. Input consists of punch cards containing project identification, program options, and position and observation information. Results listed include preliminary and final positions, residuals, observation equations, solution of the normal equations showing magnitudes of shifts, and a plot of each adjusted and fixed station. During processing, data sets containing irrecoverable errors are rejected and the type of error is listed. The computer resumes processing of additional data sets.. Other conditions cause warning-errors to be issued, and processing continues with the current data set.

  8. Proton transfer and protein conformation dynamics in photosensitive proteins by time-resolved step-scan Fourier-transform infrared spectroscopy.

    PubMed

    Lórenz-Fonfría, Víctor A; Heberle, Joachim

    2014-06-27

    Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards understanding its mechanism. Protonation and conformational changes affect the vibration pattern of amino acid side chains and of the peptide bond, respectively, both of which can be probed by infrared (IR) difference spectroscopy. For proteins whose function can be repetitively and reproducibly triggered by light, it is possible to obtain infrared difference spectra with (sub)microsecond resolution over a broad spectral range using the step-scan Fourier transform infrared technique. With -10(2)-10(3) repetitions of the photoreaction, the minimum number to complete a scan at reasonable spectral resolution and bandwidth, the noise level in the absorption difference spectra can be as low as -10(-) (4), sufficient to follow the kinetics of protonation changes from a single amino acid. Lower noise levels can be accomplished by more data averaging and/or mathematical processing. The amount of protein required for optimal results is between 5-100 µg, depending on the sampling technique used. Regarding additional requirements, the protein needs to be first concentrated in a low ionic strength buffer and then dried to form a film. The protein film is hydrated prior to the experiment, either with little droplets of water or under controlled atmospheric humidity. The attained hydration level (g of water / g of protein) is gauged from an IR absorption spectrum. To showcase the technique, we studied the photocycle of the light-driven proton-pump bacteriorhodopsin in its native purple membrane environment, and of the light-gated ion channel channelrhodopsin-2 solubilized in detergent.

  9. Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

    PubMed Central

    Lórenz-Fonfría, Víctor A.; Heberle, Joachim

    2014-01-01

    Monitoring the dynamics of protonation and protein backbone conformation changes during the function of a protein is an essential step towards understanding its mechanism. Protonation and conformational changes affect the vibration pattern of amino acid side chains and of the peptide bond, respectively, both of which can be probed by infrared (IR) difference spectroscopy. For proteins whose function can be repetitively and reproducibly triggered by light, it is possible to obtain infrared difference spectra with (sub)microsecond resolution over a broad spectral range using the step-scan Fourier transform infrared technique. With ~102-103 repetitions of the photoreaction, the minimum number to complete a scan at reasonable spectral resolution and bandwidth, the noise level in the absorption difference spectra can be as low as ~10-4, sufficient to follow the kinetics of protonation changes from a single amino acid. Lower noise levels can be accomplished by more data averaging and/or mathematical processing. The amount of protein required for optimal results is between 5-100 µg, depending on the sampling technique used. Regarding additional requirements, the protein needs to be first concentrated in a low ionic strength buffer and then dried to form a film. The protein film is hydrated prior to the experiment, either with little droplets of water or under controlled atmospheric humidity. The attained hydration level (g of water / g of protein) is gauged from an IR absorption spectrum. To showcase the technique, we studied the photocycle of the light-driven proton-pump bacteriorhodopsin in its native purple membrane environment, and of the light-gated ion channel channelrhodopsin-2 solubilized in detergent. PMID:24998200

  10. Examination of a Water-saving Type Sprinkler System with a Variable Time-step Temperature-based Controller for the Protection of Tea Shoots from Frost

    NASA Astrophysics Data System (ADS)

    Tanaka, Toshihiro; Orita, Takaaki; Uezono, Yutaka; Kanno, Masamichi; Kato, Masaaki

    In order to reduce of the amount water used for protection of new shoots from frost,we examined a sprinkler system that could adjust the amount of water supply by choosing from several watering intervals depending on the surface temperature of tea plant canopy. When the temperature of new shoots was lower than the critical level, our sprinkler system continued to supply water, and when the temperature was higher than the critical level, our system reduced the amount of precipitation. In our study area, the temperature of new shoots was higher than the critical level,which was assumed to be -2.4°C during 3 examination seasons (from 2005 to 2007). Further,compared to a fixed interval sprinkler system, our system was found to be more effective in protecting the shoots from frost and in conserving water. During the examination periods, the amount of water used by our system was about 40% of that used by the ordinary continuative sprinkler system, and it was about 80% of that used by the fixed interval sprinkler system.

  11. Stepping off the Dance Floor for a View from the Balcony: Observations for Physical Education Teacher Education Programs in Interesting Times

    ERIC Educational Resources Information Center

    Bulger, Sean M.; Hannon, James C.; Jones, Emily M.

    2016-01-01

    The theme of this article is adopted from the work of leadership experts Heifetz and Linsky, who described the need for organizational leaders to balance their time on the "dance floor" (managing tasks) with time viewing from the "balcony" (understanding the bigger picture). The physical education teacher education doctoral…

  12. Recirculating valve lash adjuster

    SciTech Connect

    Stoody, R.R.

    1987-02-24

    This patent describes an internal combustion engine with a valve assembly of the type including overhead valves supported by a cylinder head for opening and closing movements in a substantially vertical direction and a rotatable overhead camshaft thereabove lubricated by engine oil pumped by an engine oil pump. A hydraulic lash adjuster with an internal reservoir therein is solely supplied with run-off lubricating oil from the camshaft which oil is pumped into the internal reservoir of the lash adjuster by self-pumping operation of the lash adjuster produced by lateral forces thereon by the rotative operation of the camshaft comprising: a housing of the lash adjuster including an axially extending bore therethrough with a lower wall means of the housing closing the lower end thereof; a first plunger member being closely slidably received in the bore of the housing and having wall means defining a fluid filled power chamber with the lower wall means of the housing; and a second plunger member of the lash adjuster having a portion being loosely slidably received and extending into the bore of the housing for reciprocation therein. Another portion extends upwardly from the housing to operatively receive alternating side-to-side force inputs from operation of the camshaft.

  13. Chl- a triplet quenching by peridinin in H-PCP and organic solvent revealed by step-scan FTIR time-resolved spectroscopy

    NASA Astrophysics Data System (ADS)

    Bonetti, C.; Alexandre, M. T. A.; Hiller, R. G.; Kennis, J. T. M.; Grondelle, R. van

    2009-02-01

    Triplet-state dynamics in Chl- a/Per mixtures in organic solvent and in native H-PCP were studied by means of step-scan FTIR spectroscopy. A single decay component of 10 μs was observed for the H-PCP triplet, the spectrum of which closely matches the 13 μs component of A-PCP [Alexandre et al., Biophysical Journal 93 (2007) 2118-2128], implying that in H-PCP, as in A-PCP, the peridinin triplet state is shared with Chl- a. In a mixture of Chl- a and Per in THF, TEET from 3Chl- a to 3Per proceeds in 3.5 μs followed by 3Per decay in 7 μs. Using a target analysis procedure, 3Chl- a and 3Per infrared difference spectra were obtained. The specific carbonyl frequencies of 3Per and 3Chl- a in THF confirm our assignment of their co-existence in the infrared spectra of H-PCP and A-PCP.

  14. 12 CFR 1263.22 - Adjustments in stock holdings.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Adjustments in stock holdings. 1263.22 Section... Stock Requirements § 1263.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required to hold. (b)(1)...

  15. 12 CFR 1263.22 - Adjustments in stock holdings.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Adjustments in stock holdings. 1263.22 Section... Stock Requirements § 1263.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required to hold. (b)(1)...

  16. 12 CFR 925.22 - Adjustments in stock holdings.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Adjustments in stock holdings. 925.22 Section... ASSOCIATES MEMBERS OF THE BANKS Stock Requirements § 925.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required...

  17. 12 CFR 1263.22 - Adjustments in stock holdings.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Adjustments in stock holdings. 1263.22 Section... Stock Requirements § 1263.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required to hold. (b)(1)...

  18. 12 CFR 1263.22 - Adjustments in stock holdings.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Adjustments in stock holdings. 1263.22 Section... Stock Requirements § 1263.22 Adjustments in stock holdings. (a) Adjustment in general. A Bank may from time to time increase or decrease the amount of stock any member is required to hold. (b)(1)...

  19. Capping risk adjustment?

    PubMed

    Eugster, Patrick; Sennhauser, Michèle; Zweifel, Peter

    2010-07-01

    When premiums are community-rated, risk adjustment (RA) serves to mitigate competitive insurers' incentive to select favorable risks. However, unless fully prospective, it also undermines their incentives for efficiency. By capping its volume, one may try to counteract this tendency, exposing insurers to some financial risk. This in term runs counter the quest to refine the RA formula, which would increase RA volume. Specifically, the adjuster, "Hospitalization or living in a nursing home during the previous year" will be added in Switzerland starting 2012. This paper investigates how to minimize the opportunity cost of capping RA in terms of increased incentives for risk selection.

  20. Step-Growth Polymerization.

    ERIC Educational Resources Information Center

    Stille, J. K.

    1981-01-01

    Following a comparison of chain-growth and step-growth polymerization, focuses on the latter process by describing requirements for high molecular weight, step-growth polymerization kinetics, synthesis and molecular weight distribution of some linear step-growth polymers, and three-dimensional network step-growth polymers. (JN)

  1. IDEA MOE Adjustment Act

    THOMAS, 113th Congress

    Rep. Lujan, Ben Ray [D-NM-3

    2013-06-04

    07/08/2013 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  2. Automated working distance adjustment for a handheld OCT-Laryngoscope

    NASA Astrophysics Data System (ADS)

    Donner, Sabine; Bleeker, Sebastian; Ripken, Tammo; Krueger, Alexander

    2014-03-01

    Optical coherence tomography (OCT) is an imaging technique which enables diagnosis of vocal cord tissue structure by non-contact optical biopsies rather than invasive tissue biopsies. For diagnosis on awake patients OCT was adapted to a rigid indirect laryngoscope. The working distance must match the probe-sample distance, which varies from patient to patient. Therefore the endoscopic OCT sample arm has a variable working distance of 40 mm to 80 mm. The current axial position is identified by automated working distance adjustments based on image processing. The OCT reference plane and the focal plane of the sample arm are moved according to position errors. Repeated position adjustment during the whole diagnostic procedure keeps the tissue sample at the optimal axial position. The auto focus identifies and adjusts the working distance within the range of 50 mm within a maximum time of 2.7 s. Continuous image stabilisation reduces axial sample movement within the sampling depth for handheld OCT scanning. Rapid autofocus reduces the duration of the diagnostic procedure and axial position stabilisation eases the use of the OCT laryngoscope. Therefore this work is an important step towards the integration of OCT into indirect laryngoscopes.

  3. Effect of residence time on two-step liquefaction of rice straw in a CO2 atmosphere: Differences between subcritical water and supercritical ethanol.

    PubMed

    Yang, Tianhua; Wang, Jian; Li, Bingshuo; Kai, Xingping; Li, Rundong

    2017-04-01

    This study investigated the influence of temperature and residence time on liquefaction of rice straw in subcritical CO2-subcritical water (subCO2-subH2O) and in subcritical CO2-supercritical ethanol (subCO2-scEtOH), considering the final reaction temperatures (270-345°C) and residence times (15 and 30min). Residence time was identified as a crucial parameter in the subCO2-subH2O liquefaction, whereas residence time had a marginal influence on subCO2-scEtOH liquefaction. When reaction conditions were 320°C and 15min, solvents have weak impact on the quality of bio-oil, HHV 28.57MJ/kg and 28.62MJ/kg, respectively. There was an obvious difference between the subCO2-subH2O and subCO2-scEtOH liquefaction mechanisms. In subCO2-subH2O, CO2 promoted the carbonyl reaction. In subCO2-scEtOH, supercritical ethanol have the function of donating hydrogen and promoting the reaction of hydroxyl-alkylation.

  4. Tough Choices or Tough Times: Bolder Steps for Education Philanthropy? Notes and Resources from the GFE Foundation Leaders Institute (Tamaya, New Mexico, October 19, 2007)

    ERIC Educational Resources Information Center

    Mackinnon, Anne

    2007-01-01

    In late 2006, the National Center on Education and the Economy released "Tough Choices or Tough Times: The Report of the New Commission on the Skills of the American Workforce." With compelling language, the report updated and sharpened the findings of the center's influential 1990 report, "America's Choice: High Skills or Low Wages," which called…

  5. Psychological Adjustment and Homosexuality.

    ERIC Educational Resources Information Center

    Gonsiorek, John C.

    In this paper, the diverse literature bearing on the topic of homosexuality and psychological adjustment is critically reviewed and synthesized. The first chapter discusses the most crucial methodological issue in this area, the problem of sampling. The kinds of samples used to date are critically examined, and some suggestions for improved…

  6. Self Adjusting Sunglasses

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Corning Glass Works' Serengeti Driver sunglasses are unique in that their lenses self-adjust and filter light while suppressing glare. They eliminate more than 99% of the ultraviolet rays in sunlight. The frames are based on the NASA Anthropometric Source Book.

  7. Self adjusting inclinometer

    DOEpatents

    Hunter, Steven L.

    2002-01-01

    An inclinometer utilizing synchronous demodulation for high resolution and electronic offset adjustment provides a wide dynamic range without any moving components. A device encompassing a tiltmeter and accompanying electronic circuitry provides quasi-leveled tilt sensors that detect highly resolved tilt change without signal saturation.

  8. Behavioural Repertoire of Working Donkeys and Consistency of Behaviour over Time, as a Preliminary Step towards Identifying Pain-Related Behaviours

    PubMed Central

    Regan, Fran H.; Hockenhull, Jo; Pritchard, Joy C.; Waterman-Pearson, Avril E.; Whay, Helen R.

    2014-01-01

    Background The donkey has a reputation for stoicism and its behavioural repertoire in clinical contexts is under-reported. Lack of understanding of the norms of donkey behaviour and how it may vary over time can compromise use of behavioural measures as indicators of pain or emotional state. The objective of this study was to find out whether the behaviour of working donkeys was influenced by gender, the time of day or differed between days with a view to assessing how robust these measures are for inclusion in a working donkey ethogram. Methodology/Principal Findings Frequency and consistency of postural and event behaviours were measured in 21 adult working donkeys (12 females; 9 males). Instantaneous (scan) and focal sampling were used to measure maintenance, lying, ingestive and investigative behaviours at hourly intervals for ten sessions on each of two consecutive days. High head carriage and biting were seen more frequently in male donkeys than females (P<0.001). Level head carriage, licking/chewing and head-shaking were observed more frequently in female donkeys (P<0.001). Tail position, ear orientation, foot stamping, rolling/lying and head-shaking behaviours were affected by time of day (P<0.001). However, only two variations in ear orientation were found to be significantly different over the two days of observations (P<0.001). Tail swishing, head shaking, foot stamping, and ears held sideways and downwards were significantly correlated (P<0.001) and are assumed to be behaviours to discourage flies. Conclusions/Significance All donkeys expressed an extensive behavioural repertoire, although some differences in behaviour were evident between genders. While most behaviours were consistent over time, some behaviours were influenced by time of day. Few behaviours differed between the two test days. The findings can be used to inform the development of a robust, evidence-based ethogram for working donkeys. PMID:25076209

  9. Running on uneven ground: leg adjustments to altered ground level.

    PubMed

    Müller, Roy; Blickhan, Reinhard

    2010-08-01

    In locomotion, humans have to deal with changes in ground level like pavement or stairs. When they encounter uneven ground with changes in terrain height, they reduce their angle of attack and leg stiffness on a step. This strategy was found for the single step upward movement. However, are these adjustments the result of a general strategy? In our study we focused on leg adjustments while running up and down, implying permanent adaptation to a new track level. To investigate this, we measured ten healthy participants as they ran along a runway with 10 cm increased and 10 cm lowered steps. We found that ground reaction force, leg length, leg stiffness, and angle of attack were adjusted to the direction of the vertical disturbance (up or down) but also to its length. When running upwards, leg stiffness decreased by about 20.4% on the single step and by about 9.3% on the permanently elevated track step. In addition to that - when running downwards - leg stiffness decreased in preparation for the downward step by about 18.8%. We also observed that the angle of attack diminished on elevated contact from 61 degrees to 59 degrees, and increased on lowered contact from 61 degrees to 65 degrees. The adjustment of leg stiffness seemed to be actively achieved, whereas the angle of attack appeared to be passively adjusted, consistent with a running model that includes leg retraction in late swing phase.

  10. One-step synthesis of silver nanoparticles, nanorods, and nanowires on the surface of DNA network.

    PubMed

    Wei, Gang; Zhou, Hualan; Liu, Zhiguo; Song, Yonghai; Wang, Li; Sun, Lanlan; Li, Zhuang

    2005-05-12

    Here, we describe a one-step synthesis of silver nanoparticles, nanorods, and nanowires on DNA network surface in the absence of surfactant. Silver ions were first adsorbed onto the DNA network and then reduced in sodium borohydride solution. Silver nanoparticles, nanorods, and nanowires were formed by controlling the size of pores of the DNA network. The diameter of the silver nanoparticles and the aspect ratio of the silver nanorods and nanowires can be controlled by adjusting the DNA concentration and reduction time.

  11. Step by Step: Avoiding Spiritual Bypass in 12-Step Work

    ERIC Educational Resources Information Center

    Cashwell, Craig S.; Clarke, Philip B.; Graves, Elizabeth G.

    2009-01-01

    With spirituality as a cornerstone, 12-step groups serve a vital role in the recovery community. It is important for counselors to be mindful, however, of the potential for clients to be in spiritual bypass, which likely will undermine the recovery process.

  12. Simultaneous detection of influenza viruses A, B, and swine origin influenza A using multiplex one-step real-time RT-PCR assay.

    PubMed

    Monavari, S H R; Mollaie, H R; Fazlalipour, M

    2014-01-01

    Every year, seasonal epidemics of influenza viruses are causing considerable morbidity and mortality worldwide. Also infrequent novel and rearranged strains of influenza viruses have caused quick, acute universal pandemics resulting in millions of mortalities. The usage of efficient and accurate detection is superior for infection control, effective treatment, and epidemiological supervision. Therefore, evaluation of useful real-time PCR molecular tests for the detection of pandemic viruses is important before the next wave of the pandemic. A novel quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) assay with specific primers was used successfully for detection and monitoring of the influenza A, B, and swine influenza. The newly designed primers target highly conserved regions in influenza viruses. Our qRT-PCR assay is highly specific for detecting influenza A, B, and swine influenza viruses. The cutoff CT value was determined <38 for domestic human diagnostic test, under conditions of FDA emergency, and the reaction efficiency of the InfA, swInfA, and InfB assays were thereby estimated to be 97.9 % (R2 = 0.998), 98.3 % (R2 = 0.986), and 99.5 % (R2 = 0.995), respectively. Interestingly, based on our finding, there is no cross reactivity of detecting other viruses.

  13. Luminosity progression in dart-stepped leader step formation

    NASA Astrophysics Data System (ADS)

    Wang, D.; Takagi, N.; Uman, M. A.; Jordan, D. M.

    2016-12-01

    Using a high-speed optical imaging system, we have observed the step formation bright pulse discharges occurring at the tip of dart-stepped leaders of rocket triggered lightning with a time resolution of 0.1 µs and a spatial resolution of about 1.4 m. Each of the step formation pulse discharges appeared to initiate at a location immediately below the bottom of its previous pulse discharge and to propagate in bidirectional (upward and downward) waves with a speed on the order of 107 m/s. The downward waves of the pulse discharges tended to slow down significantly after they propagated a distance of about 2 m. Based on the results observed in this study and those published in literatures, we propose a conceptual view of leader step formation.

  14. Anticipatory postural adjustments are unaffected by age and are not absent in patients with the freezing of gait phenomenon.

    PubMed

    Plate, A; Klein, K; Pelykh, O; Singh, A; Bötzel, K

    2016-09-01

    In bipedal gait, the initiation of the first step is preceded by a complex sequence of movements which shift the centre of mass of the body towards the stance foot to allow for a step of the swing foot. These anticipatory postural adjustments (APAs) have been investigated in order to elucidate movement strategies in healthy and diseased persons. We studied the influence of several external parameters (age, type of step initiation) on APAs and investigated whether Parkinsonian patients may have different APAs. As a result, we found that externally elicited steps were preceded by faster and larger APAs than self-timed steps. Parkinsonian patients without the freezing of gait (FOG) phenomenon showed overall slightly reduced APAs but did not clearly differ from patients with FOG. Multiple APAs were seen in up to 25 % of the steps of the patients and in a much lower percentage of the steps of control subjects. The results indicate that APAs are significantly influenced by the timing of a step, i.e. are larger in externally elicited steps. The patients showed an overall preserved APA pattern but slowed movements and amplitude, indicating that increased bradykinesia due to progressive illness is a plausible explanation for these findings. The freezing phenomenon is not explained by a general absence or massive reduction in APA measures.

  15. Training in the step-down inhibitory avoidance task time-dependently increases cAMP-dependent protein kinase activity in the entorhinal cortex.

    PubMed

    Pereira, P; Ardenghi, P; Mello e Souza, T; Medina, J H; Izquierdo, I

    2001-06-01

    The cAMP/cAMP-dependent protein kinase (PKA) signaling pathway has been implicated in synaptic plasticity changes and memory consolidation. Several cortical structures are involved in the consolidation of memory for inhibitory avoidance. The aim of the present work was to observe the effects of training in the inhibitory avoidance task on the levels of PKA activity in the entorhinal, parietal and posterior cingulate cortex (EC, PARIET and PC), and the medial precentral area (Fr2) of the rat, at different post-training times (0, 1.5, 3 and 6h). PKA activity, assayed using [gamma-32P]ATP and kemptide, a selective substrate, increased in the EC 3 h after training, but no changes were observed in PARIET, PC and Fr2. These results suggest that the late phase of memory consolidation of inhibitory avoidance requires a functional PKA signaling pathway in the EC in a way that a 'peak' of PKA activity is observed.

  16. Commissioning of the ArDM experiment at the Canfranc underground laboratory: first steps towards a tonne-scale liquid argon time projection chamber for Dark Matter searches

    NASA Astrophysics Data System (ADS)

    Calvo, J.; Cantini, C.; Crivelli, P.; Daniel, M.; Di Luise, S.; Gendotti, A.; Horikawa, S.; Montes, B.; Mu, W.; Murphy, S.; Natterer, G.; Nguyen, K.; Periale, L.; Quan, Y.; Radics, B.; Regenfus, C.; Romero, L.; Rubbia, A.; Santorelli, R.; Sergiampietri, F.; Viant, T.; Wu, S.

    2017-03-01

    The Argon Dark Matter (ArDM) experiment consists of a liquid argon (LAr) time projection chamber (TPC) sensitive to nuclear recoils, resulting from scattering of hypothetical Weakly Interacting Massive Particles (WIMPs) on argon targets. With an active target mass of 850 kg ArDM represents an important milestone towards developments for large LAr Dark Matter detectors. Here we present the experimental apparatus currently installed underground at the Laboratorio Subterráneo de Canfranc (LSC), Spain. We show data on gaseous or liquid argon targets recorded in 2015 during the commissioning of ArDM in single phase at zero E-field (ArDM Run I). The data confirms the overall good and stable performance of the ArDM tonne-scale LAr detector.

  17. Effect of reaction temperature and time during two-step selenization and sulfurization of Se-Coated CuGa/In precursors

    NASA Astrophysics Data System (ADS)

    Koo, Jaseok; Kwon, Sunmo; Roh, Yong-Suk; Lee, Seok-Jin; Jung, Ki-Young; Shafarman, William N.; Park, Ji-Hyeon; Kim, Do Hoon; Myoung, Jae-Min; Kim, Woo Kyoung

    2016-07-01

    In this work, the selenization of Mo/CuGa/In/Se (Se layer thickness: 1 μm) precursors followed by sulfurization was investigated. Particular emphasis was placed on the effect of the variation of the selenization temperature and sulfurization time on the morphology and compositional depth profiles of the resulting Cu(InGa)(SeS)2 (CIGSS) absorber; in addition, the current-voltage characteristics of the corresponding devices were investigated. The selenization of the precursors was achieved by using a tube-type rapid thermal annealing system at various temperatures (500, 550, and 600 °C). Post-sulfurization of Cu(InGa)Se2 (CIGS) was performed in the same system by flowing H2S/He gas at 600 °C for different periods of time (5, 10, and 15 min). Post-sulfurization can improve the open-circuit voltage of a solar cell by attracting Ga toward the surface region of the light absorber and incorporating S into the absorber to yield quinary CIGSS compounds. In addition, the voids at the Mo/CIGS interface, produced during the selenization of the CuGa/In/Se precursors, were effectively removed after post-sulfurization. Among the process conditions explored in this study, the selenization of Mo/CuGa/In/Se at 550 °C for 7 min followed by sulfurization at 600 °C for 10 min produced the device with the best performance, providing also good material properties in terms of morphology and compositional homogeneity. [Figure not available: see fulltext.

  18. Precision adjustable stage

    DOEpatents

    Cutburth, Ronald W.; Silva, Leonard L.

    1988-01-01

    An improved mounting stage of the type used for the detection of laser beams is disclosed. A stage center block is mounted on each of two opposite sides by a pair of spaced ball bearing tracks which provide stability as well as simplicity. The use of the spaced ball bearing pairs in conjunction with an adjustment screw which also provides support eliminates extraneous stabilization components and permits maximization of the area of the center block laser transmission hole.

  19. Time-Adjusted Internal Target Volume: A Novel Approach Focusing on Heterogeneity of Tumor Motion Based on 4-Dimensional Computed Tomography Imaging for Radiation Therapy Planning of Lung Cancer

    SciTech Connect

    Nishibuchi, Ikuno; Kimura, Tomoki; Nakashima, Takeo; Ochi, Yusuke; Takahashi, Ippei; Doi, Yoshiko; Kenjo, Masahiro; Kaneyasu, Yuko; Ozawa, Syuichi; Murakami, Yuji; Wadasaki, Koichi; Nagata, Yasushi

    2014-08-01

    Purpose: To consider nonuniform tumor motion within the internal target volume (ITV) by defining time-adjusted ITV (TTV), a volume designed to include heterogeneity of tumor existence on the basis of 4-dimensional computed tomography (4D-CT). Methods and Materials: We evaluated 30 lung cancer patients. Breath-hold CT (BH-CT) and free-breathing 4D-CT scans were acquired for each patient. The tumors were manually delineated using a lung CT window setting (window, 1600 HU; level, −300 HU). Tumor in BH-CT images was defined as gross tumor volume (GTV), and the sum of tumors in 4D-CT images was defined as ITV-4D. The TTV images were generated from the 4D-CT datasets, and the tumor existence probability within ITV-4D was calculated. We calculated the TTV{sub 80} value, which is the percentage of the volume with a tumor existence probability that exceeded 80% on ITV-4D. Several factors that affected the TTV{sub 80} value, such as the ITV-4D/GTV ratio or tumor centroid deviation, were evaluated. Results: Time-adjusted ITV images were acquired for all patients, and tumor respiratory motion heterogeneity was visualized. The median (range) ITV-4D/GTV ratio and median tumor centroid deviation were 1.6 (1.0-4.1) and 6.3 mm (0.1-30.3 mm), respectively. The median TTV{sub 80} value was 43.3% (2.9-98.7%). Strong correlations were observed between the TTV{sub 80} value and the ITV-4D/GTV ratio (R=−0.71) and tumor centroid deviation (R=−0.72). The TTV images revealed the tumor motion pattern features within ITV. Conclusions: The TTV images reflected nonuniform tumor motion, and they revealed the tumor motion pattern features, suggesting that the TTV concept may facilitate various aspects of radiation therapy planning of lung cancer while incorporating respiratory motion in the future.

  20. Modelling in-stream temperature and dissolved oxygen at sub-daily time steps: an application to the River Kennet, UK.

    PubMed

    Williams, Richard J; Boorman, David B

    2012-04-15

    The River Kennet in southern England shows a clear diurnal signal in both water temperature and dissolved oxygen concentrations through the summer months. The water quality model QUESTOR was applied in a stepwise manner (adding modelled processes or additional data) to simulate the flow, water temperature and dissolved oxygen concentrations along a 14 km reach. The aim of the stepwise model building was to find the simplest process-based model which simulated the observed behaviour accurately. The upstream boundary used was a diurnal signal of hourly measurements of water temperature and dissolved oxygen. In the initial simulations, the amplitude of the signal quickly reduced to zero as it was routed through the model; a behaviour not seen in the observed data. In order to keep the correct timing and amplitude of water temperature a heating term had to be introduced into the model. For dissolved oxygen, primary production from macrophytes was introduced to better simulate the oxygen pattern. Following the modifications an excellent simulation of both water temperature and dissolved oxygen was possible at an hourly resolution. It is interesting to note that it was not necessary to include nutrient limitation to the primary production model. The resulting model is not sufficiently proven to support river management but suggests that the approach has some validity and merits further development.

  1. Identification of different respiratory viruses, after a cell culture step, by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS)

    PubMed Central

    Calderaro, Adriana; Arcangeletti, Maria Cristina; Rodighiero, Isabella; Buttrini, Mirko; Montecchini, Sara; Vasile Simone, Rosita; Medici, Maria Cristina; Chezzi, Carlo; De Conto, Flora

    2016-01-01

    In this study matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS), a reliable identification method for the diagnosis of bacterial and fungal infections, is presented as an innovative tool to investigate the protein profile of cell cultures infected by the most common viruses causing respiratory tract infections in humans. MALDI-TOF MS was applied to the identification of influenza A and B viruses, adenovirus C species, parainfluenza virus types 1, 2 and 3, respiratory syncytial virus, echovirus, cytomegalovirus and metapneumovirus. In this study MALDI-TOF MS was proposed as a model to be applied to the identification of cultivable respiratory viruses using cell culture as a viral proteins enrichment method to the proteome profiling of virus infected and uninfected cell cultures. The reference virus strains and 58 viruses identified from respiratory samples of subjects with respiratory diseases positive for one of the above mentioned viral agents by cell culture were used for the in vitro infection of suitable cell cultures. The isolated viral particles, concentrated by ultracentrifugation, were used for subsequent protein extraction and their spectra profiles were generated by MALDI-TOF MS analysis. The newly created library allowed us to discriminate between uninfected and respiratory virus infected cell cultures. PMID:27786297

  2. Development and evaluation of a one-step real-time RT-PCR assay for universal detection of influenza A viruses from avian and mammal species.

    PubMed

    Nagy, Alexander; Vostinakova, Veronika; Pirchanova, Zuzana; Cernikova, Lenka; Dirbakova, Zuzana; Mojzis, Miroslav; Jirincova, Helena; Havlickova, Martina; Dan, Adam; Ursu, Krisztina; Vilcek, Stefan; Hornickova, Jitka

    2010-05-01

    The objective of our study was to develop and evaluate a TaqMan real-time RT-PCR (RRT-PCR) assay for universal detection of influenza A (IA) viruses. The primers and LNA-modified octanucleotide probe were selected to correspond to extremely conserved regions of the membrane protein (MP) segment identified by a comprehensive bioinformatics analysis including 10,405 IA viruses MP sequences, i.e., all of the sequences of the Influenza Virus Sequence database collected as of August 20, 2009. The RRT-PCR has a detection limit of approximately five copies of target RNA/reaction and excellent reaction parameters tested in four IA viruses reference laboratories. The inclusivity of the assay was estimated at both the bioinformatic and the experimental level. Our results predicted that this RRT-PCR assay was able to detect 99.5% of known human IA virus strains, 99.84% of pandemic influenza A (H1N1) strains, 99.75% of avian strains, 98.89% of swine strains, 98.15% of equine strains, and 100% of influenza A viruses of other origin.

  3. Stair-stepped Mound

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-429, 22 July 2003

    This April 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a stair-stepped mound of sedimentary rock (right of center) on the floor of a large impact crater in western Arabia Terra near 11.0oN, 4.4oW. Sedimentary rock outcrops are common in the craters of this region. The repeated thickness and uniformity of the layers that make up this mound suggest that their depositional environment was one in which cyclic or episodic events occurred over some period of time. The sediments might have been deposited in a lake, or they may have settled directly out of the atmosphere. Most of the layered material was later eroded away, leaving this circular mound and the other nearby mesas and knobs. The image is illuminated by sunlight from the lower left.

  4. A Step Circuit Program.

    ERIC Educational Resources Information Center

    Herman, Susan

    1995-01-01

    Aerobics instructors can use step aerobics to motivate students. One creative method is to add the step to the circuit workout. By incorporating the step, aerobic instructors can accommodate various fitness levels. The article explains necessary equipment and procedures, describing sample stations for cardiorespiratory fitness, muscular strength,…

  5. Development and evaluation of one-step TaqMan real-time reverse transcription-PCR assays targeting nucleoprotein, matrix, and hemagglutinin genes of equine influenza virus.

    PubMed

    Lu, Zhengchun; Chambers, Thomas M; Boliar, Saikat; Branscum, Adam J; Sturgill, Tracy L; Timoney, Peter J; Reedy, Stephanie E; Tudor, Lynn R; Dubovi, Edward J; Vickers, Mary Lynne; Sells, Stephen; Balasuriya, Udeni B R

    2009-12-01

    The objective of this study was to develop and evaluate new TaqMan real-time reverse transcription-PCR (rRT-PCR) assays by the use of the minor groove binding probe to detect a wide range of equine influenza virus (EIV) strains comprising both subtypes of the virus (H3N8 and H7N7). A total of eight rRT-PCR assays were developed, targeting the nucleoprotein (NP), matrix (M), and hemagglutinin (HA) genes of the two EIV subtypes. None of the eight assays cross-reacted with any of the other known equine respiratory viruses. Three rRT-PCR assays (EqFlu NP, M, and HA3) which can detect strains of the H3N8 subtype were evaluated using nasal swabs received for routine diagnosis and swabs collected from experimentally inoculated horses. All three rRT-PCR assays have greater specificity and sensitivity than virus isolation by egg inoculation (93%, 89%, and 87% sensitivity for EqFlu NP, EqFlu M, and EqFlu HA3 assays, respectively). These assays had analytical sensitivities of >or=10 EIV RNA molecules. Comparison of the sensitivities of rRT-PCR assays targeting the NP and M genes of both subtypes with egg inoculation and the Directigen Flu A test clearly shows that molecular assays provide the highest sensitivity. The EqFlu HA7 assay targeting the H7 HA gene is highly specific for the H7N7 subtype of EIV. It should enable highly reliable surveillance for the H7N7 subtype, which is thought to be extinct or possibly still circulating at a very low level in nature. The assays that we developed provide a fast and reliable means of EIV diagnosis and subtype identification of EIV subtypes.

  6. STEPS: Moving from Welfare to Work.

    ERIC Educational Resources Information Center

    Vail, Ann; Cummings, Merrilyn; Kratzer, Connie; Galindo, Vickie

    Cooperative extension service faculty at New Mexico State University started the Steps to Employment and Personal Success (STEPS) program to help Temporary Assistance for Needy Families (TANF) clients qualify for and maintain full-time employment and strengthen their families for long-term success. Clients are referred to STEPS by New Mexico…

  7. A Future-Oriented Retirement Transition Adjustment Framework

    ERIC Educational Resources Information Center

    Hesketh, Beryl; Griffin, Barbara; Loh, Vanessa

    2011-01-01

    This theoretical paper presents a person-environment fit framework that extends the Minnesota Theory of Work Adjustment to retirement transition and adjustment. The proposed Retirement Transition and Adjustment Framework (RTAF) also accommodates dynamic intra-individual and environment change over time, configural combinations of variables, and an…

  8. Comment on 'Shang S. 2012. Calculating actual crop evapotranspiration under soil water stress conditions with appropriate numerical methods and time step. Hydrological Processes 26: 3338-3343. DOI: 10.1002/hyp.8405'

    NASA Technical Reports Server (NTRS)

    Yatheendradas, Soni; Narapusetty, Balachandrudu; Peters-Lidard, Christa; Funk, Christopher; Verdin, James

    2014-01-01

    A previous study analyzed errors in the numerical calculation of actual crop evapotranspiration (ET(sub a)) under soil water stress. Assuming no irrigation or precipitation, it constructed equations for ET(sub a) over limited soil-water ranges in a root zone drying out due to evapotranspiration. It then used a single crop-soil composite to provide recommendations about the appropriate usage of numerical methods under different values of the time step and the maximum crop evapotranspiration (ET(sub c)). This comment reformulates those ET(sub a) equations for applicability over the full range of soil water values, revealing a dependence of the relative error in numerical ET(sub a) on the initial soil water that was not seen in the previous study. It is shown that the recommendations based on a single crop-soil composite can be invalid for other crop-soil composites. Finally, a consideration of the numerical error in the time-cumulative value of ET(sub a) is discussed besides the existing consideration of that error over individual time steps as done in the previous study. This cumulative ET(sub a) is more relevant to the final crop yield.

  9. Evaluation of the one-step multiplex real-time reverse transcription-PCR ProFlu-1 assay for detection of influenza A and influenza B viruses and respiratory syncytial viruses in children.

    PubMed

    Legoff, Jérôme; Kara, Rachid; Moulin, Florence; Si-Mohamed, Ali; Krivine, Anne; Bélec, Laurent; Lebon, Pierre

    2008-02-01

    We evaluated the one-step multiplex real-time reverse transcription-PCR ProFlu-1 assay for the detection of influenza A and influenza B viruses and respiratory syncytial viruses from 353 pediatric nasopharyngeal aspirates. As assessed by comparison with the results of immunofluorescence testing and cell culture, the specificity and the sensitivity of the ProFlu-1 assay ranged from 97% to 100%. In addition, the ProFlu-1 assay amplified 9% of samples not detected by conventional methods.

  10. Evaluation of the One-Step Multiplex Real-Time Reverse Transcription-PCR ProFlu-1 Assay for Detection of Influenza A and Influenza B Viruses and Respiratory Syncytial Viruses in Children▿

    PubMed Central

    LeGoff, Jérôme; Kara, Rachid; Moulin, Florence; Si-Mohamed, Ali; Krivine, Anne; Bélec, Laurent; Lebon, Pierre

    2008-01-01

    We evaluated the one-step multiplex real-time reverse transcription-PCR ProFlu-1 assay for the detection of influenza A and influenza B viruses and respiratory syncytial viruses from 353 pediatric nasopharyngeal aspirates. As assessed by comparison with the results of immunofluorescence testing and cell culture, the specificity and the sensitivity of the ProFlu-1 assay ranged from 97% to 100%. In addition, the ProFlu-1 assay amplified 9% of samples not detected by conventional methods. PMID:18057126

  11. Adjustable Reeds For Weaving

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1994-01-01

    Local characteristics of fabrics varied to suit special applications. Adjustable reed machinery proposed for use in weaving fabrics in various net shapes, widths, yarn spacings, and yarn angles. Locations of edges of fabric and configuration of warp and filling yarns varied along fabric to obtain specified properties. In machinery, reed wires mounted in groups on sliders, mounted on lengthwise rails in reed frame. Mechanisms incorporated to move sliders lengthwise, parallel to warp yarns, by sliding them along rails; move sliders crosswise by translating reed frame rails perpendicular to warp yarns; and crosswise by spreading reed rails within group. Profile of reed wires in group on each slider changed.

  12. Multi-Scale 7DOF View Adjustment.

    PubMed

    Cho, Isaac; Li, Jialei; Wartell, Zachary

    2017-02-13

    Multi-scale virtual environments contain geometric details ranging over several orders of magnitude and typically employ out-of-core rendering techniques. When displayed in virtual reality systems this entails using a 7 degree-of-freedom (DOF) view model where view scale is a separate 7th DOF in addition to 6DOF view pose. Dynamic adjustment of this and other view parameters become very important to usability. In this paper, we evaluate how two adjustment techniques interact with uni- and bi-manual 7 degree-of-freedom navigation in DesktopVR and a CAVE. The travel task has two stages, an initial targeted zoom and a detailed geometric inspection. The results show benefits of the auto-adjustments on completion time and stereo fusion issues, but only in certain circumstances. Peculiar view configuration examples show the difficulty of creating robust adjustment rules.

  13. Continuously adjustable Pulfrich spectacles

    NASA Astrophysics Data System (ADS)

    Jacobs, Ken; Karpf, Ron

    2011-03-01

    A number of Pulfrich 3-D movies and TV shows have been produced, but the standard implementation has inherent drawbacks. The movie and TV industries have correctly concluded that the standard Pulfrich 3-D implementation is not a useful 3-D technique. Continuously Adjustable Pulfrich Spectacles (CAPS) is a new implementation of the Pulfrich effect that allows any scene containing movement in a standard 2-D movie, which are most scenes, to be optionally viewed in 3-D using inexpensive viewing specs. Recent scientific results in the fields of human perception, optoelectronics, video compression and video format conversion are translated into a new implementation of Pulfrich 3- D. CAPS uses these results to continuously adjust to the movie so that the viewing spectacles always conform to the optical density that optimizes the Pulfrich stereoscopic illusion. CAPS instantly provides 3-D immersion to any moving scene in any 2-D movie. Without the glasses, the movie will appear as a normal 2-D image. CAPS work on any viewing device, and with any distribution medium. CAPS is appropriate for viewing Internet streamed movies in 3-D.

  14. Assignment of IR bands of isolated and protein-bound Peridinin in its fundamental and triplet state by static FTIR, time-resolved step-scan FTIR and DFT calculations

    NASA Astrophysics Data System (ADS)

    Mezzetti, Alberto; Kish, Elizabeth; Robert, Bruno; Spezia, Riccardo

    2015-06-01

    The vibrational properties of Peridinin in its fundamental state and in the excited triplet state have been investigated by DFT calculations and static and time-resolved FTIR spectroscopy. The infrared spectrum of Peridinin in its fundamental state has been explored in the whole 2000-600 cm-1 range, and interpreted in term of molecular vibrations. In particular, new infrared bands have been identified and assigned to specific molecular vibrations. 3Peridinin molecular vibrations have also been investigated by DFT calculations. In addition, putative IR bands belonging to Peridinin and 3Peridinin have been identified in the step-scan FTIR difference spectrum of the Peridinin-Chlorophyll a-Protein from Amphidinium carterae, where light induce formation of a triplet state localized on one or more Peridinins. The exact nature of the triplet state formed in Peridinin-Chlorophyll a-Protein from dinoflagellates, in particular the possible involvement in this triplet state of 3Chlorophyll a, has been largely debated in the last few years (see Carbonera et al., 2014 [3]); time-resolved differential FTIR experiments have played a key role in this debate. Identification of IR marker bands for the main molecule (Peridinin) implicated in this photophysical process is therefore particularly important and makes this study a significant step towards the full understanding of Peridinin-Chlorophyll-a-Proteins photophysics.

  15. Ionic liquid-based one-step micellar extraction of multiclass polar compounds from hawthorn fruits by ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry.

    PubMed

    Hu, Shuai-Shuai; Yi, Ling; Li, Xing-Ying; Cao, Jun; Ye, Li-Hong; Cao, Wan; Da, Jian-Hua; Dai, Han-Bin; Liu, Xiao-Juan

    2014-06-11

    An ionic liquid (IL)-based one-step micellar extraction procedure was developed for the extraction of multiclass polar analytes (protocatechuic acid, chlorogenic acid, epicatechin, hyperoside, isoquercitrin, quercetin) from hawthorn fruits and their determination using ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF/MS). Compared to conventional organic solvent extractions, this newly proposed method was much easier, more sensitive, environmentally friendly, and effective as well. Several important parameters influencing the micellar extraction efficiency are discussed, such as selection of ILs, surfactant concentration, and extraction time. Under the optimal conditions, good linearity was achieved for each analyte with correlation coefficients (r(2)) ranging from 0.9934 to 0.9999, and the recovery values ranged from 89.3 to 106% with relative standard deviations lower than 5.5%. Results suggest that the IL-based one-step micellar extraction could be an alternative and promising means in future food analysis.

  16. Numerical Integration: One Step at a Time

    ERIC Educational Resources Information Center

    Yang, Yajun; Gordon, Sheldon P.

    2016-01-01

    This article looks at the effects that adding a single extra subdivision has on the level of accuracy of some common numerical integration routines. Instead of automatically doubling the number of subdivisions for a numerical integration rule, we investigate what happens with a systematic method of judiciously selecting one extra subdivision for…

  17. PID controller auto-tuning based on process step response and damping optimum criterion.

    PubMed

    Pavković, Danijel; Polak, Siniša; Zorc, Davor

    2014-01-01

    This paper presents a novel method of PID controller tuning suitable for higher-order aperiodic processes and aimed at step response-based auto-tuning applications. The PID controller tuning is based on the identification of so-called n-th order lag (PTn) process model and application of damping optimum criterion, thus facilitating straightforward algebraic rules for the adjustment of both the closed-loop response speed and damping. The PTn model identification is based on the process step response, wherein the PTn model parameters are evaluated in a novel manner from the process step response equivalent dead-time and lag time constant. The effectiveness of the proposed PTn model parameter estimation procedure and the related damping optimum-based PID controller auto-tuning have been verified by means of extensive computer simulations.

  18. Particular adaptations to potentially slippery surfaces: the effects of friction on consecutive postural adjustments (CPA).

    PubMed

    Memari, Sahel; Le Bozec, Serge; Bouisset, Simon

    2014-02-21

    This research deals with the postural adjustments that occur after the end of voluntary movement ("consecutive postural adjustments": CPAs). The influence of a potentially slippery surface on CPA characteristics was considered, with the aim of exploring more deeply the postural component of the task-movement. Seven male adults were asked to perform a single step, as quickly as possible, to their own footprint marked on the ground. A force plate measured the resultant reaction forces along the antero-posterior axis (R(x)) and the centre of pressure (COP) displacements along the antero-posterior and lateral axes (Xp and Yp). The velocity of the centre of gravity (COG) along the antero-posterior axis and the corresponding impulse (∫R(x)dt) were calculated; the peak velocity (termed "progression velocity": V(xG)) was measured. The required coefficient of friction (RCOF) along the progression axis (pμ(x)) was determined. Two materials, differing by their COF, were laid at foot contact (FC), providing a rough foot contact (RoFC), and a smooth foot contact (SmFC) considered to be potentially slippery. Two step lengths were also performed: a short step (SS) and a long step (LS). Finally, the subjects completed four series of ten steps each. These were preceded by preliminary trials, to allow them to acquire the necessary adaptation to experimental conditions. The antero-posterior force time course presented a positive phase, that included APAs ("anticipatory postural adjustments") and step execution (STEP), followed by a negative one, corresponding to CPAs. The backward impulse (CPI) was equal to the forward one (BPI), independently of friction and progression velocity. Moreover, V(xG) did not differ according to friction, but was faster when the step length was greater. Last CPA peak amplitudes (pCPA) were significantly greater and CPA durations (dCPA) shorter for RoFC and conversely for SmFC, contrary to APA. Finally, the results show a particular adaptation to the

  19. Emotion Regulation Profiles, Temperament, and Adjustment Problems in Preadolescents

    ERIC Educational Resources Information Center

    Zalewski, Maureen; Lengua, Liliana J.; Wilson, Anna C.; Trancik, Anika; Bazinet, Alissa

    2011-01-01

    The longitudinal relations of emotion regulation profiles to temperament and adjustment in a community sample of preadolescents (N = 196, 8-11 years at Time 1) were investigated using person-oriented latent profile analysis (LPA). Temperament, emotion regulation, and adjustment were measured at 3 different time points, with each time point…

  20. Information on stepping motors

    NASA Astrophysics Data System (ADS)

    Fongarland, G.

    1982-04-01

    The principles of the stepping motors which are often used in servomechanisms are reviewed. Variable reluctance as well as permanent magnet stepping motors are considered. Their operation is explained which includes permanent rotation, starting, stopping, and resonance effects. Several application examples, drawn from problems in automation, are outlined.

  1. 12 CFR Appendix E to Part 1024 - Arithmetic Steps

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... annual disbursements Settlement: May 15 First Payment: July 1 Step 1—Initial Trial Balance Aggregate pmt... Step 2—Adjusted Trial Balance Aggregate pmt disb bal Jun 0 0 780 Jul 130 500 410 Aug 130 0 540 Sep 130... 520 May 130 0 650 Jun 130 0 780 Step 3—Trial Balance With Cushion Aggregate pmt disb bal Jun 0 0...

  2. 12 CFR Appendix E to Part 1024 - Arithmetic Steps

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... annual disbursements Settlement: May 15 First Payment: July 1 Step 1—Initial Trial Balance Aggregate pmt... Step 2—Adjusted Trial Balance Aggregate pmt disb bal Jun 0 0 780 Jul 130 500 410 Aug 130 0 540 Sep 130... 520 May 130 0 650 Jun 130 0 780 Step 3—Trial Balance With Cushion Aggregate pmt disb bal Jun 0 0...

  3. 12 CFR Appendix E to Part 1024 - Arithmetic Steps

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... annual disbursements Settlement: May 15 First Payment: July 1 Step 1—Initial Trial Balance Aggregate pmt... Step 2—Adjusted Trial Balance Aggregate pmt disb bal Jun 0 0 780 Jul 130 500 410 Aug 130 0 540 Sep 130... 520 May 130 0 650 Jun 130 0 780 Step 3—Trial Balance With Cushion Aggregate pmt disb bal Jun 0 0...

  4. STEP Experiment Requirements

    NASA Technical Reports Server (NTRS)

    Brumfield, M. L. (Compiler)

    1984-01-01

    A plan to develop a space technology experiments platform (STEP) was examined. NASA Langley Research Center held a STEP Experiment Requirements Workshop on June 29 and 30 and July 1, 1983, at which experiment proposers were invited to present more detailed information on their experiment concept and requirements. A feasibility and preliminary definition study was conducted and the preliminary definition of STEP capabilities and experiment concepts and expected requirements for support services are presented. The preliminary definition of STEP capabilities based on detailed review of potential experiment requirements is investigated. Topics discussed include: Shuttle on-orbit dynamics; effects of the space environment on damping materials; erectable beam experiment; technology for development of very large solar array deployers; thermal energy management process experiment; photovoltaic concentrater pointing dynamics and plasma interactions; vibration isolation technology; flight tests of a synthetic aperture radar antenna with use of STEP.

  5. The Stepping Stone Approach

    NASA Astrophysics Data System (ADS)

    Brumfitt, A.

    Education is a profession in its own right. It has its own parameters, passions and language. Having the responsibility both of educare and educere, education has a focus of delivering specific factual knowledge whilst drawing out the creative mind. Space Science is a special vehicle having the properties of both educare and educere. It has a magic and wonder that touches the very essence of an individual and his place in time and space; it offers the "wow" factor that all teachers strive for. Space Science is the wrapping paper for other elements in the curriculum, e.g. cross-curricula and skill-based activities, such as language development, creativity, etc. as well as the pure sciences which comprise of engineering, physics and other natural sciences from astronomy to chemistry to biology. Each of these spheres of influence are relevant from kindergarten to undergraduate studies and complement, and in addition support informal education in museums, science centers and the world of e-learning. ESA Science Education has devised the "Stepping Stone Approach" to maximize the greatest outreach to all education stakeholders in Europe. In this paper we illustrate how to best reach these target groups with very specific activities to trigger and sustain enthusiasm whilst supporting the pedagogical, subject content and skill-based needs of a prescribed curriculum.

  6. Design and validation of an H5 TaqMan real-time one-step reverse transcription-PCR and confirmatory assays for diagnosis and verification of influenza A virus H5 infections in humans.

    PubMed

    Ellis, Joanna S; Smith, Joanne W; Braham, Sharleen; Lock, Matthew; Barlow, Katrina; Zambon, Maria C

    2007-05-01

    Increasing diversity among influenza H5N1 viruses has resulted in the need for sensitive and specific diagnostic assays, fully validated for the detection of H5 viruses belonging to all hemagglutinin (HA) clades, particularly the recently circulating H5N1 viruses of clade 2. In this report, the development and validation of a real-time, one-step TaqMan reverse transcription-PCR (RT-PCR) assay specific for the detection of influenza A H5 viruses from clades 1, 1', 2, and 3 is described. The real-time assay for H5 virus was shown to be highly sensitive, detecting H5 virus levels of <1 PFU from each of the HA clades. Specificity of the H5 RT-PCR for influenza A H5 viruses was demonstrated by using influenza A viruses of different subtypes, clinical samples containing influenza A viruses H1N1, H3N2, and H5N1, influenza B viruses, and other respiratory viruses. The usefulness of the inclusion of a distinguishable assay positive control and of confirmatory assays for the laboratory diagnosis and verification of H5 virus infections was demonstrated. A real-time RT-PCR pyrosequencing assay, a restriction enzyme digestion assay, and direct sequencing of the H5 real-time RT-PCR amplicon were validated for the confirmation of H5 detection by the diagnostic real-time assay. The H5 real-time assay was applied to diagnostic testing for suspected cases of influenza A virus H5 infection in the United Kingdom. Influenza A H5 viruses were not detected in the cases analyzed; however, influenza A H3N2 virus was detected in 57% of the suspected cases of H5. The H5 TaqMan real-time RT-PCR and confirmatory assays will be useful tools for the laboratory surveillance and rapid diagnosis of H5 infections in humans.

  7. Methods for automatic trigger threshold adjustment

    DOEpatents

    Welch, Benjamin J; Partridge, Michael E

    2014-03-18

    Methods are presented for adjusting trigger threshold values to compensate for drift in the quiescent level of a signal monitored for initiating a data recording event, thereby avoiding false triggering conditions. Initial threshold values are periodically adjusted by re-measuring the quiescent signal level, and adjusting the threshold values by an offset computation based upon the measured quiescent signal level drift. Re-computation of the trigger threshold values can be implemented on time based or counter based criteria. Additionally, a qualification width counter can be utilized to implement a requirement that a trigger threshold criterion be met a given number of times prior to initiating a data recording event, further reducing the possibility of a false triggering situation.

  8. Detection of Steps in Single Molecule Data

    PubMed Central

    Aggarwal, Tanuj; Materassi, Donatello; Davison, Robert; Hays, Thomas; Salapaka, Murti

    2013-01-01

    Over the past few decades, single molecule investigations employing optical tweezers, AFM and TIRF microscopy have revealed that molecular behaviors are typically characterized by discrete steps or events that follow changes in protein conformation. These events, that manifest as steps or jumps, are short-lived transitions between otherwise more stable molecular states. A major limiting factor in determining the size and timing of the steps is the noise introduced by the measurement system. To address this impediment to the analysis of single molecule behaviors, step detection algorithms incorporate large records of data and provide objective analysis. However, existing algorithms are mostly based on heuristics that are not reliable and lack objectivity. Most of these step detection methods require the user to supply parameters that inform the search for steps. They work well, only when the signal to noise ratio (SNR) is high and stepping speed is low. In this report, we have developed a novel step detection method that performs an objective analysis on the data without input parameters, and based only on the noise statistics. The noise levels and characteristics can be estimated from the data providing reliable results for much smaller SNR and higher stepping speeds. An iterative learning process drives the optimization of step-size distributions for data that has unimodal step-size distribution, and produces extremely low false positive outcomes and high accuracy in finding true steps. Our novel methodology, also uniquely incorporates compensation for the smoothing affects of probe dynamics. A mechanical measurement probe typically takes a finite time to respond to step changes, and when steps occur faster than the probe response time, the sharp step transitions are smoothed out and can obscure the step events. To address probe dynamics we accept a model for the dynamic behavior of the probe and invert it to reveal the steps. No other existing method addresses

  9. Delay Adjusted Incidence

    Cancer.gov

    This Infographic shows the National Cancer Institute SEER Incidence Trends. The graphs show the Average Annual Percent Change (AAPC) 2002-2011. For Men, Thyroid: 5.3*,Liver & IBD: 3.6*, Melanoma: 2.3*, Kidney: 2.0*, Myeloma: 1.9*, Pancreas: 1.2*, Leukemia: 0.9*, Oral Cavity: 0.5, Non-Hodgkin Lymphoma: 0.3*, Esophagus: -0.1, Brain & ONS: -0.2*, Bladder: -0.6*, All Sites: -1.1*, Stomach: -1.7*, Larynx: -1.9*, Prostate: -2.1*, Lung & Bronchus: -2.4*, and Colon & Rectum: -3/0*. For Women, Thyroid: 5.8*, Liver & IBD: 2.9*, Myeloma: 1.8*, Kidney: 1.6*, Melanoma: 1.5, Corpus & Uterus: 1.3*, Pancreas: 1.1*, Leukemia: 0.6*, Brain & ONS: 0, Non-Hodgkin Lymphoma: -0.1, All Sites: -0.1, Breast: -0.3, Stomach: -0.7*, Oral Cavity: -0.7*, Bladder: -0.9*, Ovary: -0.9*, Lung & Bronchus: -1.0*, Cervix: -2.4*, and Colon & Rectum: -2.7*. * AAPC is significantly different from zero (p<.05). Rates were adjusted for reporting delay in the registry. www.cancer.gov Source: Special section of the Annual Report to the Nation on the Status of Cancer, 1975-2011.

  10. Nonlinear Hydrostatic Adjustment.

    NASA Astrophysics Data System (ADS)

    Bannon, Peter R.

    1996-12-01

    The final equilibrium state of Lamb's hydrostatic adjustment problem is found for finite amplitude heating. Lamb's problem consists of the response of a compressible atmosphere to an instantaneous, horizontally homogeneous heating. Results are presented for both isothermal and nonisothermal atmospheres.As in the linear problem, the fluid displacements are confined to the heated layer and to the region aloft with no displacement of the fluid below the heating. The region above the heating is displaced uniformly upward for heating and downward for cooling. The amplitudes of the displacements are larger for cooling than for warming.Examination of the energetics reveals that the fraction of the heat deposited into the acoustic modes increases linearly with the amplitude of the heating. This fraction is typically small (e.g., 0.06% for a uniform warming of 1 K) and is essentially independent of the lapse rate of the base-state atmosphere. In contrast a fixed fraction of the available energy generated by the heating goes into the acoustic modes. This fraction (e.g., 12% for a standard tropospheric lapse rate) agrees with the linear result and increases with increasing stability of the base-state atmosphere.The compressible results are compared to solutions using various forms of the soundproof equations. None of the soundproof equations predict the finite amplitude solutions accurately. However, in the small amplitude limit, only the equations for deep convection advanced by Dutton and Fichtl predict the thermodynamic state variables accurately for a nonisothermal base-state atmosphere.

  11. Examining changes in relationship adjustment and life satisfaction in marriage.

    PubMed

    Stanley, Scott M; Ragan, Erica P; Rhoades, Galena K; Markman, Howard J

    2012-02-01

    The current study examined the association between relationship adjustment and life satisfaction before marriage to 6 years into marriage in a sample of 126 couples. Results showed that both premarital relationship adjustment and premarital life satisfaction uniquely predicted marital adjustment 6 years into marriage. Premarital life satisfaction, but not premarital relationship adjustment, predicted life satisfaction 6 years into marriage. While premarital relationship adjustment scores were not uniquely associated with future life satisfaction scores, changes in relationship adjustment were positively associated with future life satisfaction. These findings are supportive of the idea that helping people to improve their relationships may increase overall life satisfaction. The findings also suggest that, while an individual's base level of life satisfaction may set some parameters for the course of relationship adjustment, changes in life satisfaction over time impact marital adjustment. Starting marriage with higher life satisfaction may increase chances for a happier marriage. Overall, the findings suggest that life satisfaction plays a role in marital adjustment over time, and that it is important to consider life satisfaction as not only an outcome associated with relationship adjustment but also as a predictor of relationship adjustment.

  12. Timing Is Everything: A Comparative Study of the Adjustment Process of Fall and Mid-Year Community College Transfer Students at a Public Four-Year University. Working Paper Series. Number 1-10

    ERIC Educational Resources Information Center

    Peska, Scott F.

    2009-01-01

    This sequential mixed method study (Creswell, 2003) compared the adjustment process of community college transfer students who began in the fall to those who began mid-year, beginning with a quantitative phase and extending to a qualitative phase of data collection in the fall semester and repeating this same sequence of data gathering with…

  13. The Next Giant Step

    NASA Video Gallery

    Artist Robert McCall painted "The Next Giant Step" in 1979 to commemorate the heroism and courage of spaceflight pioneers. Located in the lobby of Johnson's building 2, the mural depicts America's ...

  14. CEIP Next Steps

    EPA Pesticide Factsheets

    The Clean Energy Incentive Program (CEIP) next steps document details the EPA’s outreach strategy for stakeholder input on the design and implementation of the CEIP. Additionally, this document lists provisions on the CEIP where stakeholder input is sought

  15. Room for Adjustment

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2006-01-01

    In classrooms across the U.S., students spend untold hours sitting at desks and tables working on their lessons or listening to their teachers. That lack of movement might not have been a concern years ago, when children's time away from school typically was spent outdoors playing and exercising. However, as children spend more time in front of a…

  16. Effects of Maternal Depression on Youth Adjustment.

    ERIC Educational Resources Information Center

    Alexander, Jennifer

    Depressive disorders are chronic illnesses affecting women and their families for extended periods of time. This paper summarizes research related to the effects of maternal depression on children's short and long term adjustment. Children of depressed mothers are at risk for internalizing and externalizing disorders. Genetics account for a small…

  17. The African Development Bank, structural adjustment, and child mortality: a cross-national analysis of Sub-Saharan Africa.

    PubMed

    Pandolfelli, Lauren E; Shandra, John M

    2013-01-01

    We conduct a cross-national analysis to test the hypothesis that African Development Bank (AfDB) structural adjustment adversely impacts child mortality in Sub-Saharan Africa. We use generalized least square random effects regression models and two-step Heckman models that correct for selection bias using data on 35 nations with up to four time points (1990, 1995, 2000, and 2005). We find substantial support for our hypothesis, which indicates that Sub-Saharan African nations that receive an AfDB structural adjustment loan tend to have higher levels of child mortality than Sub-Saharan African nations that do not receive such a loan. This finding remains stable even when controlling for selection bias on whether or not a Sub-Saharan African nation receives an AfDB structural adjustment loan. We conclude by discussing the methodological implications of the article, policy suggestions, and possible directions for future research.

  18. Adjustable gastric banding (image)

    MedlinePlus

    ... normal digestive process. In this procedure, a hollow band made of special material is placed around the ... pouch and causes a feeling of fullness. The band can be tightened or loosened over time to ...

  19. Psychosocial adjustment to ALS: a longitudinal study.

    PubMed

    Matuz, Tamara; Birbaumer, Niels; Hautzinger, Martin; Kübler, Andrea

    2015-01-01

    For the current study the Lazarian stress-coping theory and the appendant model of psychosocial adjustment to chronic illness and disabilities (Pakenham, 1999) has shaped the foundation for identifying determinants of adjustment to ALS. We aimed to investigate the evolution of psychosocial adjustment to ALS and to determine its long-term predictors. A longitudinal study design with four measurement time points was therefore, used to assess patients' quality of life, depression, and stress-coping model related aspects, such as illness characteristics, social support, cognitive appraisals, and coping strategies during a period of 2 years. Regression analyses revealed that 55% of the variance of severity of depressive symptoms and 47% of the variance in quality of life at T2 was accounted for by all the T1 predictor variables taken together. On the level of individual contributions, protective buffering, and appraisal of own coping potential accounted for a significant percentage in the variance in severity of depressive symptoms, whereas problem management coping strategies explained variance in quality of life scores. Illness characteristics at T2 did not explain any variance of both adjustment outcomes. Overall, the pattern of the longitudinal results indicated stable depressive symptoms and quality of life indices reflecting a successful adjustment to the disease across four measurement time points during a period of about two years. Empirical evidence is provided for the predictive value of social support, cognitive appraisals, and coping strategies, but not illness parameters such as severity and duration for adaptation to ALS. The current study contributes to a better conceptualization of adjustment, allowing us to provide evidence-based support beyond medical and physical intervention for people with ALS.

  20. Psychosocial adjustment to ALS: a longitudinal study

    PubMed Central

    Matuz, Tamara; Birbaumer, Niels; Hautzinger, Martin; Kübler, Andrea

    2015-01-01

    For the current study the Lazarian stress-coping theory and the appendant model of psychosocial adjustment to chronic illness and disabilities (Pakenham, 1999) has shaped the foundation for identifying determinants of adjustment to ALS. We aimed to investigate the evolution of psychosocial adjustment to ALS and to determine its long-term predictors. A longitudinal study design with four measurement time points was therefore, used to assess patients' quality of life, depression, and stress-coping model related aspects, such as illness characteristics, social support, cognitive appraisals, and coping strategies during a period of 2 years. Regression analyses revealed that 55% of the variance of severity of depressive symptoms and 47% of the variance in quality of life at T2 was accounted for by all the T1 predictor variables taken together. On the level of individual contributions, protective buffering, and appraisal of own coping potential accounted for a significant percentage in the variance in severity of depressive symptoms, whereas problem management coping strategies explained variance in quality of life scores. Illness characteristics at T2 did not explain any variance of both adjustment outcomes. Overall, the pattern of the longitudinal results indicated stable depressive symptoms and quality of life indices reflecting a successful adjustment to the disease across four measurement time points during a period of about two years. Empirical evidence is provided for the predictive value of social support, cognitive appraisals, and coping strategies, but not illness parameters such as severity and duration for adaptation to ALS. The current study contributes to a better conceptualization of adjustment, allowing us to provide evidence-based support beyond medical and physical intervention for people with ALS. PMID:26441696

  1. An improved accrual: reducing medical malpractice year-end adjustments.

    PubMed

    Frese, Richard C

    2012-08-01

    Healthcare organizations can improve their year-end malpractice insurance accruals by taking the following steps: Maintain productive communication. Match accrual and accounting policies. Adjust amount of credit to own historical loss experience. Request more frequent analysis. Obtain a second opinion.

  2. Spousal Adjustment to Myocardial Infarction.

    ERIC Educational Resources Information Center

    Ziglar, Elisa J.

    This paper reviews the literature on the stresses and coping strategies of spouses of patients with myocardial infarction (MI). It attempts to identify specific problem areas of adjustment for the spouse and to explore the effects of spousal adjustment on patient recovery. Chapter one provides an overview of the importance in examining the…

  3. Online mutability of step direction during rapid stepping reactions evoked by postural perturbation.

    PubMed

    Tripp, Bryan P; McIlroy, William E; Maki, Brian E

    2004-03-01

    Stepping reactions are often triggered rapidly in response to loss of balance. It has been unclear whether spatial step parameters are defined at time of step-initiation or whether they can be modulated online, during step execution, in response to sensory feedback about the evolving state of instability. This study explored the capacity to actively alter step direction subsequent to step initiation in six healthy young-adult subjects. To elicit forward-step reactions, subjects were released suddenly from a tethered forward lean. A second perturbation (medio-lateral support-surface translation) was applied at lags of 0-200 ms. Active reaction to the second perturbation was determined primarily through analysis of swing-leg hip-abductor activation. In addition, to gauge the biomechanical consequence of the changes in muscle activation, we compared the measured medio-lateral swing-foot displacement to that predicted by a simple passive mechanical model. Perturbations at 0-100 ms lag evoked active medio-lateral swing-foot deviation, allowing balance to be recovered with a single step. However, when the second perturbation occurred near foot-off (200-ms lag), there was no evidence of active alteration of step direction and subjects typically required additional steps to recover balance. The results suggest that step direction can be reparameterized during early stages of stepping reactions, but that step direction was not actively modulated in response to perturbation arising near start of swing phase.

  4. Trajectories of adjustment to couple relationship separation.

    PubMed

    Halford, W Kim; Sweeper, Susie

    2013-06-01

    To test a stress-diathesis model of adjustment to separation, the current study describes the trajectories of different aspects of separation adjustment in people formerly married or cohabiting, and moderators of those trajectories. A convenience sample of 303 recently separated individuals (169 women; 134 men) completed assessments of their emotional attachment to the former partner, loneliness, psychological distress, and coparenting conflict at two time points 6 months apart. Multilevel modeling of the overlapping multicohort design was used to estimate the trajectories of these different aspects of adjustment as a function of time since separation, marital status, gender, presence of children from the relationship, who initiated separation, social support, and anxious attachment. Attachment to the former partner, loneliness, and psychological distress were initially high but improved markedly across the 2 years after separation, but coparenting conflict was high and stable. Adjustment problems were similar in men and women, and in those formerly married or cohabiting, except that reported coparenting conflict was higher in men than women. Low social support and high anxious attachment predicted persistent attachment to the former partner, loneliness, and psychological distress. Coparenting conflict is a common, chronic problem for many separated individuals, and individuals with certain psychological vulnerabilities also experience chronic personal distress.

  5. Stepped inlet optical panel

    DOEpatents

    Veligdan, James T.

    2001-01-01

    An optical panel includes stacked optical waveguides having stepped inlet facets collectively defining an inlet face for receiving image light, and having beveled outlet faces collectively defining a display screen for displaying the image light channeled through the waveguides by internal reflection.

  6. Development of a Real-Time PCR for a Sensitive One-Step Coprodiagnosis Allowing both the Identification of Carnivore Feces and the Detection of Toxocara spp. and Echinococcus multilocularis

    PubMed Central

    Umhang, Gérald; Poulle, Marie-Lazarine; Millon, Laurence

    2016-01-01

    Studying the environmental occurrence of parasites of concern for humans and animals based on coprosamples is an expanding field of work in epidemiology and the ecology of health. Detecting and quantifying Toxocara spp. and Echinococcus multilocularis, two predominant zoonotic helminths circulating in European carnivores, in feces may help to better target measures for prevention. A rapid, sensitive, and one-step quantitative PCR (qPCR) allowing detection of E. multilocularis and Toxocara spp. was developed in the present study, combined with a host fecal test based on the identification of three carnivores (red fox, dog, and cat) involved in the life cycles of these parasites. A total of 68 coprosamples were collected from identified specimens from Vulpes vulpes, Canis lupus familiaris, Canis lupus, Felis silvestris catus, Meles meles, Martes foina, and Martes martes. With DNA coprosamples, real-time PCR was performed in duplex with a qPCR inhibitor control specifically designed for this study. All the coprosample host identifications were confirmed by qPCR combined with sequencing, and parasites were detected and confirmed (E. multilocularis in red foxes and Toxocara cati in cats; 16% of samples presented inhibition). By combining parasite detection and quantification, the host fecal test, and a new qPCR inhibitor control, we created a technique with a high sensitivity that may considerably improve environmental studies of pathogens. PMID:26969697

  7. Development of a Real-Time PCR for a Sensitive One-Step Coprodiagnosis Allowing both the Identification of Carnivore Feces and the Detection of Toxocara spp. and Echinococcus multilocularis.

    PubMed

    Knapp, Jenny; Umhang, Gérald; Poulle, Marie-Lazarine; Millon, Laurence

    2016-05-15

    Studying the environmental occurrence of parasites of concern for humans and animals based on coprosamples is an expanding field of work in epidemiology and the ecology of health. Detecting and quantifying Toxocara spp. and Echinococcus multilocularis, two predominant zoonotic helminths circulating in European carnivores, in feces may help to better target measures for prevention. A rapid, sensitive, and one-step quantitative PCR (qPCR) allowing detection of E. multilocularis and Toxocara spp. was developed in the present study, combined with a host fecal test based on the identification of three carnivores (red fox, dog, and cat) involved in the life cycles of these parasites. A total of 68 coprosamples were collected from identified specimens from Vulpes vulpes, Canis lupus familiaris, Canis lupus, Felis silvestris catus, Meles meles, Martes foina, and Martes martes With DNA coprosamples, real-time PCR was performed in duplex with a qPCR inhibitor control specifically designed for this study. All the coprosample host identifications were confirmed by qPCR combined with sequencing, and parasites were detected and confirmed (E. multilocularis in red foxes and Toxocara cati in cats; 16% of samples presented inhibition). By combining parasite detection and quantification, the host fecal test, and a new qPCR inhibitor control, we created a technique with a high sensitivity that may considerably improve environmental studies of pathogens.

  8. Exploration adjustment by ant colonies

    PubMed Central

    2016-01-01

    How do animals in groups organize their work? Division of labour, i.e. the process by which individuals within a group choose which tasks to perform, has been extensively studied in social insects. Variability among individuals within a colony seems to underpin both the decision over which tasks to perform and the amount of effort to invest in a task. Studies have focused mainly on discrete tasks, i.e. tasks with a recognizable end. Here, we study the distribution of effort in nest seeking, in the absence of new nest sites. Hence, this task is open-ended and individuals have to decide when to stop searching, even though the task has not been completed. We show that collective search effort declines when colonies inhabit better homes, as a consequence of a reduction in the number of bouts (exploratory events). Furthermore, we show an increase in bout exploration time and a decrease in bout instantaneous speed for colonies inhabiting better homes. The effect of treatment on bout effort is very small; however, we suggest that the organization of work performed within nest searching is achieved both by a process of self-selection of the most hard-working ants and individual effort adjustment. PMID:26909180

  9. Evaluation and application of a one-step duplex real-time reverse transcription polymerase chain reaction assay for the rapid detection of influenza A (H7N9) virus from poultry samples.

    PubMed

    Bao, Hongmei; Ma, Yong; Shi, Jianzhong; Zeng, Xianying; Zhao, Yuhui; Wang, Xiurong; Chen, Hualan

    2015-10-01

    In China, a novel reassortant influenza A (H7N9) virus, which has caused 435 cases of human infection, has recently emerged. Most cases of human infections with the H7N9 virus are known to be associated with a poultry farm and live-poultry markets. In this study, a one-step duplex real-time reverse transcription polymerase chain reaction (RRT-PCR) assay was developed for the simultaneous detection of the hemagglutinin (HA) and neuraminidase (NA) genes of the H7N9 virus for effective surveillance and early diagnosis of cases from clinical samples collected from live-poultry markets or poultry farms. The detection limit of this assay was as low as 0.1 EID50 of H7N9 viruses, which is similar to the detection limit of the real-time RT-PCR assay released by the Word Health Organization. The coefficients of variation (CVs) of both inter-assay and intra-assay reproducibility were less than 1.55 %, showing good reproducibility. No cross-reactivity was observed with RNA of other subtypes of influenza virus or other avian respiratory viruses. The assay can effectively detect H7N9 influenza virus RNA from multiple sources, including chickens, pigeons, ducks, humans, and the environment. Furthermore, the RRT-PCR assay was evaluated with more than 700 clinical samples collected from live-poultry markets and 120 experimentally infected chicken samples. Together, these results indicate that the duplex RRT-PCR assay is a specific, sensitive, and efficient diagnostic method for the epidemiological surveillance and diagnosis of H7N9 virus from different sources, particularly poultry samples.

  10. Undertaking a literature review: a step-by-step approach.

    PubMed

    Cronin, Patricia; Ryan, Frances; Coughlan, Michael

    Nowadays, most nurses, pre- and post-qualification, will be required to undertake a literature review at some point, either as part of a course of study, as a key step in the research process, or as part of clinical practice development or policy. For student nurses and novice researchers it is often seen as a difficult undertaking. It demands a complex range of skills, such as learning how to define topics for exploration, acquiring skills of literature searching and retrieval, developing the ability to analyse and synthesize data as well as becoming adept at writing and reporting, often within a limited time scale. The purpose of this article is to present a step-by-step guide to facilitate understanding by presenting the critical elements of the literature review process. While reference is made to different types of literature reviews, the focus is on the traditional or narrative review that is undertaken, usually either as an academic assignment or part of the research process.

  11. The design and application of a field-transportable time- of-flight mass spectrometer (ATOFMS) and use of two-step laser desorption/ionization (L2MS) to determine PAH in single particles

    NASA Astrophysics Data System (ADS)

    Morrical, Bradley Douglas

    2000-11-01

    In order to improve the ability of aerosol time-of-flight mass spectrometry (ATOFMS) to achieve the complete chemical characterization of single particles, new refinements in instrumentation and techniques have been developed. This thesis describes the design and construction of two field transportable ATOFMS instruments that allows for real-time single particle aerosol measurements for the first time in remote locations. Additionally, this new ATOFMS instrument is capable of obtaining both positive and negative ion spectra simultaneously, enabling easier identification of chemical species on a particle. Improvements to the particle inlet interface, particle sizing, and integration of electronics were also realized by the new design. To demonstrate proof of concept, the field transportable ATOFMS instruments were used to make field measurements in September and October of 1996. From field data collected, heterogeneous chemical reactions were observed for two different types of chemical systems, namely the formation of NaNO3 in sea salt particles in Long Beach, CA and the formation of NH4NO 3 on particles in Riverside, CA. It was found that both chemical systems depended heavily on wind trajectories and the length of time an air parcel remained stagnated over urban areas. Quantitation of NH4 + and NO3- is achieved by calibrating ATOFMS counts and ion signal to measured NH4+ and NO3- concentrations from conventional sampling and analysis. The second part of this thesis describes the development of a new laser ionization technique, two step laser desorption/ionization (L2MS), in order to improve the chemical characterization of organic compounds on single particles. Using L2MS, identification of a large number of polycyclic aromatic hydrocarbons (PAH) is achieved with several common combustion sources. An attempt is made to use selected PAH as markers for different combustion sources. Method of sample collection is also explored to understand the bias that particle

  12. 12 CFR 160.35 - Adjustments to home loans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... property to be occupied by the borrower, adjustments to the interest rate, payment, balance, or term to...) Adjustments to the interest rate shall correspond directly to the movement of an index satisfying the... rate pursuant to a formula or schedule that specifies the amount of the increase, the time at which...

  13. 26 CFR 1.6411-3 - Allowance of adjustments.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... related adjustment, the Commissioner may correct any mathematical error appearing on the application and...) Time prescribed. The Commissioner shall act upon any application for a tentative carryback adjustment... later: (1) The date the application is filed; or (2) The last day of the month in which falls the...

  14. 26 CFR 1.6411-3 - Allowance of adjustments.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... related adjustment, the Commissioner may correct any mathematical error appearing on the application and...) Time prescribed. The Commissioner shall act upon any application for a tentative carryback adjustment... later: (1) The date the application is filed; or (2) The last day of the month in which falls the...

  15. 26 CFR 1.6411-3 - Allowance of adjustments.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... related adjustment, the Commissioner may correct any mathematical error appearing on the application and...) Time prescribed. The Commissioner shall act upon any application for a tentative carryback adjustment... later: (1) The date the application is filed; or (2) The last day of the month in which falls the...

  16. 26 CFR 1.6411-3 - Allowance of adjustments.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... related adjustment, the Commissioner may correct any mathematical error appearing on the application and...) Time prescribed. The Commissioner shall act upon any application for a tentative carryback adjustment... later: (1) The date the application is filed; or (2) The last day of the month in which falls the...

  17. Adolescent Adjustment Before and After HIV-Related Parental Death.

    ERIC Educational Resources Information Center

    Rotheram-Borus, Mary Jane; Weiss, Robert; Alber, Susan; Lester, Patricia

    2005-01-01

    The impact of HIV-related parental death on 414 adolescents was examined over a period of 6 years. The adjustment of bereaved adolescents was compared over 4 time periods relative to parental death and was also compared with the adjustment of nonbereaved adolescents. Bereaved adolescents had significantly more emotional distress, negative life…

  18. Planned Hypothesis Tests Are Not Necessarily Exempt from Multiplicity Adjustment

    ERIC Educational Resources Information Center

    Frane, Andrew V.

    2015-01-01

    Scientific research often involves testing more than one hypothesis at a time, which can inflate the probability that a Type I error (false discovery) will occur. To prevent this Type I error inflation, adjustments can be made to the testing procedure that compensate for the number of tests. Yet many researchers believe that such adjustments are…

  19. 10 CFR 766.104 - Reconciliation, adjustments and appeals.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Reconciliation, adjustments and appeals. (a) A domestic utility requesting an adjustment shall, within 30 days... probative information, DOE will consider utility requests for up to 90 days additional time, providing that... Energy, 1000 Independence Avenue S.W., Washington, DC 20585. Except for the Fiscal Year 1993...

  20. 10 CFR 766.104 - Reconciliation, adjustments and appeals.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Reconciliation, adjustments and appeals. (a) A domestic utility requesting an adjustment shall, within 30 days... probative information, DOE will consider utility requests for up to 90 days additional time, providing that... Energy, 1000 Independence Avenue S.W., Washington, DC 20585. Except for the Fiscal Year 1993...

  1. 10 CFR 766.104 - Reconciliation, adjustments and appeals.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Reconciliation, adjustments and appeals. (a) A domestic utility requesting an adjustment shall, within 30 days... probative information, DOE will consider utility requests for up to 90 days additional time, providing that... Energy, 1000 Independence Avenue S.W., Washington, DC 20585. Except for the Fiscal Year 1993...

  2. Step Prototype Development Status

    NASA Astrophysics Data System (ADS)

    Mehls, C.; Bayart, C.; Bower, J.; Clarke, B.; Cox, C.; Gill, D.; Stricker, D.; Vora, N.; Wang, S.; Zhou, P.; Torii, R.; Worden, P.; Debra, D.; Dittus, H.; Loeffler, F.

    2008-09-01

    STEP, the Satellite Test of the Equivalence Principle [1], proposes to test the Equivalence Principle to a part in 1018 by comparing the free-fall acceleration of cylindrical shaped test masses [2] in Earth orbit. Magnetic bearings constrain the test mass motion to their axis of symmetry [3]. The displacement of the test masses is measured using a DC SQUID and superconducting coils [4], enabling a displacement sensitivity as small as 10-15 m. In combination with a small spring stiffness a differential acceleration sensitivity of 10-18 g is achievable. Residual satellite acceleration is reduced to better than 10-14 g by compensating satellite drag forces with thrust provided by helium gas. We report on recent progress in the development of STEP prototype flight accelerometers, in particular the development of the high precision quartz housing for the engineering inner accelerometer and the testing of SQUID and capacitive readout systems using 'brass board' accelerometer prototypes.

  3. The digital step edge

    NASA Technical Reports Server (NTRS)

    Haralick, R. M.

    1982-01-01

    The facet model was used to accomplish step edge detection. The essence of the facet model is that any analysis made on the basis of the pixel values in some neighborhood has its final authoritative interpretation relative to the underlying grey tone intensity surface of which the neighborhood pixel values are observed noisy samples. Pixels which are part of regions have simple grey tone intensity surfaces over their areas. Pixels which have an edge in them have complex grey tone intensity surfaces over their areas. Specially, an edge moves through a pixel only if there is some point in the pixel's area having a zero crossing of the second directional derivative taken in the direction of a non-zero gradient at the pixel's center. To determine whether or not a pixel should be marked as a step edge pixel, its underlying grey tone intensity surface was estimated on the basis of the pixels in its neighborhood.

  4. Stepped frequency ground penetrating radar

    DOEpatents

    Vadnais, Kenneth G.; Bashforth, Michael B.; Lewallen, Tricia S.; Nammath, Sharyn R.

    1994-01-01

    A stepped frequency ground penetrating radar system is described comprising an RF signal generating section capable of producing stepped frequency signals in spaced and equal increments of time and frequency over a preselected bandwidth which serves as a common RF signal source for both a transmit portion and a receive portion of the system. In the transmit portion of the system the signal is processed into in-phase and quadrature signals which are then amplified and then transmitted toward a target. The reflected signals from the target are then received by a receive antenna and mixed with a reference signal from the common RF signal source in a mixer whose output is then fed through a low pass filter. The DC output, after amplification and demodulation, is digitized and converted into a frequency domain signal by a Fast Fourier Transform. A plot of the frequency domain signals from all of the stepped frequencies broadcast toward and received from the target yields information concerning the range (distance) and cross section (size) of the target.

  5. Rectus muscle plication using an adjustable technique

    PubMed Central

    Velez, Federico G.; Demer, Joseph L.; Pihlblad, Matthew S.; Pineles, Stacy L.

    2013-01-01

    Background Rectus muscle plication is an alternative muscle-strengthening procedure to rectus muscle resection. Possible advantages of rectus muscle plication include a lower risk of “lost” muscles and anterior segment ischemia. Methods This was a retrospective case series describing a surgical procedure for rectus muscle plication using an adjustable suture technique that can be employed on any of the four rectus muscles. Results A total of 5 adult patients underwent adjustable suture plication procedures. Of these, 2 patients required suture adjustment postoperatively. At the final follow-up visit, all of the patients maintained satisfactory ocular alignment within 6Δ of orthotropia for horizontal deviations and 2Δ of orthotropia for vertical deviations. Diplopia was eliminated in all cases with preoperative diplopia. There were no postoperative complications or unexpected shifts in ocular alignment. Conclusions Rectus muscle plication using this adjustable suture technique may serve as an alternative to rectus muscle resection and may be particularly useful in patients who are at risk for anterior segment ischemia or those in whom a shorter anesthesia time is recommended. PMID:24160967

  6. Do Adjusting-Amount and Adjusting-Delay Procedures Produce Equivalent Estimates of Subjective Value in Pigeons?

    ERIC Educational Resources Information Center

    Green, Leonard; Myerson, Joel; Shah, Anuj K.; Estle, Sara J.; Holt, Daniel D.

    2007-01-01

    The current experiment examined whether adjusting-amount and adjusting-delay procedures provide equivalent measures of discounting. Pigeons' discounting on the two procedures was compared using a within-subject yoking technique in which the indifference point (number of pellets or time until reinforcement) obtained with one procedure determined…

  7. 24 CFR Appendix E to Part 3500 - Arithmetic Steps

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Payment: July 1 Step 1—Initial Trial Balance Aggregate pmt disb bal Jun 0 0 0 Jul 130 500 −370 Aug 130 0... 130 0 −390 Apr 130 0 −260 May 130 0 −130 Jun 130 0 0 Step 2—Adjusted Trial Balance Aggregate pmt disb... Balance With Cushion Aggregate pmt disb bal Jun 0 0 1040 Jul 130 500 670 Aug 130 0 800 Sep 130 360 570...

  8. 24 CFR Appendix E to Part 3500 - Arithmetic Steps

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Payment: July 1 Step 1—Initial Trial Balance Aggregate pmt disb bal Jun 0 0 0 Jul 130 500 −370 Aug 130 0... 130 0 −390 Apr 130 0 −260 May 130 0 −130 Jun 130 0 0 Step 2—Adjusted Trial Balance Aggregate pmt disb... Balance With Cushion Aggregate pmt disb bal Jun 0 0 1040 Jul 130 500 670 Aug 130 0 800 Sep 130 360 570...

  9. 24 CFR Appendix E to Part 3500 - Arithmetic Steps

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Payment: July 1 Step 1—Initial Trial Balance Aggregate pmt disb bal Jun 0 0 0 Jul 130 500 −370 Aug 130 0... 130 0 −390 Apr 130 0 −260 May 130 0 −130 Jun 130 0 0 Step 2—Adjusted Trial Balance Aggregate pmt disb... Balance With Cushion Aggregate pmt disb bal Jun 0 0 1040 Jul 130 500 670 Aug 130 0 800 Sep 130 360 570...

  10. 24 CFR Appendix E to Part 3500 - Arithmetic Steps

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Payment: July 1 Step 1—Initial Trial Balance Aggregate pmt disb bal Jun 0 0 0 Jul 130 500 −370 Aug 130 0... 130 0 −390 Apr 130 0 −260 May 130 0 −130 Jun 130 0 0 Step 2—Adjusted Trial Balance Aggregate pmt disb... Balance With Cushion Aggregate pmt disb bal Jun 0 0 1040 Jul 130 500 670 Aug 130 0 800 Sep 130 360 570...

  11. 24 CFR Appendix E to Part 3500 - Arithmetic Steps

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Payment: July 1 Step 1—Initial Trial Balance Aggregate pmt disb bal Jun 0 0 0 Jul 130 500 −370 Aug 130 0... 130 0 −390 Apr 130 0 −260 May 130 0 −130 Jun 130 0 0 Step 2—Adjusted Trial Balance Aggregate pmt disb... Balance With Cushion Aggregate pmt disb bal Jun 0 0 1040 Jul 130 500 670 Aug 130 0 800 Sep 130 360 570...

  12. Four-dimensional dose distributions of step-and-shoot IMRT delivered with real-time tumor tracking for patients with irregular breathing: Constant dose rate vs dose rate regulation

    SciTech Connect

    Yang Xiaocheng; Han-Oh, Sarah; Gui Minzhi; Niu Ying; Yu, Cedric X.; Yi Byongyong

    2012-09-15

    Purpose: Dose-rate-regulated tracking (DRRT) is a tumor tracking strategy that programs the MLC to track the tumor under regular breathing and adapts to breathing irregularities during delivery using dose rate regulation. Constant-dose-rate tracking (CDRT) is a strategy that dynamically repositions the beam to account for intrafractional 3D target motion according to real-time information of target location obtained from an independent position monitoring system. The purpose of this study is to illustrate the differences in the effectiveness and delivery accuracy between these two tracking methods in the presence of breathing irregularities. Methods: Step-and-shoot IMRT plans optimized at a reference phase were extended to remaining phases to generate 10-phased 4D-IMRT plans using segment aperture morphing (SAM) algorithm, where both tumor displacement and deformation were considered. A SAM-based 4D plan has been demonstrated to provide better plan quality than plans not considering target deformation. However, delivering such a plan requires preprogramming of the MLC aperture sequence. Deliveries of the 4D plans using DRRT and CDRT tracking approaches were simulated assuming the breathing period is either shorter or longer than the planning day, for 4 IMRT cases: two lung and two pancreatic cases with maximum GTV centroid motion greater than 1 cm were selected. In DRRT, dose rate was regulated to speed up or slow down delivery as needed such that each planned segment is delivered at the planned breathing phase. In CDRT, MLC is separately controlled to follow the tumor motion, but dose rate was kept constant. In addition to breathing period change, effect of breathing amplitude variation on target and critical tissue dose distribution is also evaluated. Results: Delivery of preprogrammed 4D plans by the CDRT method resulted in an average of 5% increase in target dose and noticeable increase in organs at risk (OAR) dose when patient breathing is either 10% faster or

  13. Capacitor charging FET switcher with controller to adjust pulse width

    DOEpatents

    Mihalka, Alex M.

    1986-01-01

    A switching power supply includes an FET full bridge, a controller to drive the FETs, a programmable controller to dynamically control final output current by adjusting pulse width, and a variety of protective systems, including an overcurrent latch for current control. Power MOSFETS are switched at a variable frequency from 20-50 kHz to charge a capacitor load from 0 to 6 kV. A ferrite transformer steps up the DC input. The transformer primary is a full bridge configuration with the FET switches and the secondary is fed into a high voltage full wave rectifier whose output is connected directly to the energy storage capacitor. The peak current is held constant by varying the pulse width using predetermined timing resistors and counting pulses. The pulse width is increased as the capacitor charges to maintain peak current. A digital ripple counter counts pulses, and after the desired number is reached, an up-counter is clocked. The up-counter output is decoded to choose among different resistors used to discharge a timing capacitor, thereby determining the pulse width. A current latch shuts down the supply on overcurrent due to either excessive pulse width causing transformer saturation or a major bridge fault, i.e., FET or transformer failure, or failure of the drive circuitry.

  14. Capacitor charging FET switcher with controller to adjust pulse width

    NASA Astrophysics Data System (ADS)

    Mihalka, A. M.

    1986-04-01

    A switching power supply includes an FET full bridge, a controller to drive the FETs, a programmable controller to dynamically control final output current by adjusting pulse width, and a variety of protective systems, including an overcurrent latch for current control. Power MOSFETS are switched at a variable frequency from 20 to 50 kHz to charge a capacitor load from 0 to 6 kV. A ferrite transformer steps up the dc input. The transformer primary is a full bridge configuration with the FET switches and the secondary is fed into a high voltage full wave rectifier whose output is connected directly to the energy storage capacitor. The peak current is held constant by varying the pulse width using predetermined timing resistors and counting pulses. The pulse width is increased as the capacitor charges to maintain peak current. A digital ripple counter counts pulses, and after the desired number is reached, an up-counter is clocked. The up-counter output is decoded to choose among different resistors used to discharge a timing capacitor, thereby determining the pulse width. A current latch shuts down the supply on overcurrent due to either excessive pulse width causing transformer saturation or a major bridge fault, i.e., FET or transformer failure, or failure of the drive circuitry.

  15. Evaluation of a real-time two-step RT-PCR assay for quantitation of Chronic bee paralysis virus (CBPV) genome in experimentally-infected bee tissues and in life stages of a symptomatic colony.

    PubMed

    Blanchard, Philippe; Ribière, Magali; Celle, Olivier; Lallemand, Perrine; Schurr, Frank; Olivier, Violaine; Iscache, Anne Laure; Faucon, Jean Paul

    2007-04-01

    A two-step real-time RT-PCR assay, based on TaqMan technology using a fluorescent probe (FAM-TAMRA) was developed to quantify Chronic bee paralysis virus (CBPV) genome in bee samples. Standard curves obtained from a CBPV control RNA and from a plasmid containing a partial sequence of CBPV showed that this assay provided linear detection over a 7-log range (R(2)>0.99) with a limit of detection of 100 copies, and reliable inter-assay and intra-assay reproducibility. Standardisation including RNA purification and cDNAs synthesis was also validated. The CBPV TaqMan methodology was first evaluated by quantifying the CBPV genomic load in bee samples from an experimental infection obtained by topical application. Up to 1.9 x 10(10) CBPV copies per segment of insect body (head, thorax and abdomen) were revealed whereas a lower CBPV genomic load was detected in dissected organs such as mandibular and hypopharyngeal glands, brain and alimentary canal (up to 7.2 x 10(6) CBPV copies). The CBPV genomic loads in different categories of bees from a hive presenting the trembling symptoms typical of Chronic paralysis were then quantified. Significantly higher CBPV loads were found in guard, symptomatic and dead bees (up to 1.9 x 10(13) CBPV copies) than in forager, drones and house bees (up to 3.4 x 10(6) CBPV copies). The results obtained for symptomatic or dead bees support the correlation between high CBPV genomic load and pathology expression. Moreover, the high CBPV genomic load revealed in guard bees highlights the possible pivotal role played by this category of bees in CBPV infection.

  16. Micromachined needles and lancets with design adjustable bevel angles

    NASA Astrophysics Data System (ADS)

    Sparks, Douglas; Hubbard, Timothy

    2004-08-01

    A new method of micromachining hollow needles and two-dimensional needle arrays from single crystal silicon is described. The process involves a combination of fusion bonding, photolithography and anisotropic plasma etching. The cannula produced with this process can have design adjustable bevel angles, wall thickness and channel dimensions. A subset of processing steps can be employed to produce silicon blades and lancets with design adjustable bevel angles and shaft dimensions. Applications for this technology include painless drug infusion, blood diagnosis, glucose monitoring, cellular injection and the manufacture of microkeratomes for ocular, vascular and neural microsurgery.

  17. Step proof mass dynamics

    NASA Astrophysics Data System (ADS)

    Wiegand, M.; Scheithauer, S.; Theil, S.

    2004-05-01

    The Satellite Test of Equivalence Principle (STEP) is a joint European-US project to investigate one of the most fundamental principles in physics, the Equivalence of inertia and passive gravitational mass. As STEP matures into a flight program, the development of a precise spacecraft dynamics simulator becomes crucial. The simulator is primarily needed for design, test and verification of the drag-free control (DFC) system and the flight software. The drag-free concept involves centering the proof mass located inside a satellite. As the proof mass is free of external disturbances (drag free), it follows a purely gravitational orbit. Since the satellite is forced to follow the proof mass, it too follows the same gravitational orbit, canceling all non-gravitational forces. For the STEP Mission, the DFC system is required to attenuate any disturbance forces acting on the spacecraft to achieve residual acceleration at location of the accelerometer of less than 3×10 -14 m/s2 (rms) across the measurement bandwidth. While the simulator is based on a high-fidelity six-degree-of-freedom numerical simulation, a simplified model is used to analyze the proof mass dynamics. The stability analysis of the proof mass motion is performed by transformation of the simplified model into the standard form of the Mathieu differential equation. The stability regions of the solution are applied to choose proper values for parameters like coupling forces between satellite and proof mass as a function of spacecraft rotation. The paper describes the calculation of the spacecraft/payload dynamics and the assumptions used to derive the underlying algorithms with a special emphasis on numerical precision issues.

  18. New photolithography stepping machine

    SciTech Connect

    Hale, L.; Klingmann, J.; Markle, D.

    1995-03-08

    A joint development project to design a new photolithography steeping machine capable of 150 nanometer overlay accuracy was completed by Ultratech Stepper and the Lawrence Livermore National Laboratory. The principal result of the project is a next-generation product that will strengthen the US position in step-and-repeat photolithography. The significant challenges addressed and solved in the project are the subject of this report. Design methods and new devices that have broader application to precision machine design are presented in greater detail while project specific information serves primarily as background and motivation.

  19. Steps to the moon

    USGS Publications Warehouse

    ,; Dale, Alvin E.

    1976-01-01

    On July 20, 1969, man walked on the surface of the Moon and began a new chapter of his studies that will eventually disclose the geologic nature of the Earth's nearest neighbor. Although he has finally reached the Moon and sampled its substance, much work and study remain before he will know the full scientific significance of the first landing. This booklet briefly summarizes the steps man has taken to understand the Moon and what he thinks he has learned to date as a result of his centuries-long speculations and studies.

  20. A Reconfigurable Stepping Motor

    NASA Astrophysics Data System (ADS)

    Rogers, Charles; Selvaggi, Richard

    2009-04-01

    Multiphase brushless actuators, commonly known as the stepper motors, are ubiquitous for many precision control applications. Developments in the microelectronics have lead to their use as efficient drive motors for modern electric vehicles. Understanding the physics and the control logic for interfacing these transducers continues to be important for scientists and engineers. An overview of the stepping motor principles and interfacing requirements is presented and a simple working model used to teach the concepts of stepper motors is described and demonstrated. This model was used to design a much larger stepper motor required to precisely rotate a massive optical system in the undergraduate advanced physics laboratory.