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Sample records for altered smooth pursuit

  1. Doing smooth pursuit paradigms in Windows 7

    DEFF Research Database (Denmark)

    Wilms, Inge Linda

    Smooth pursuit eye movements are interesting to study as they reflect the subject’s ability to predict movement of external targets, keep focus and move the eyes appropriately. The process of smooth pursuit requires collaboration between several systems in the brain and the resulting action may p...... in Windows 7 with live capturing of eye movements using a Tobii TX300 eye tracker. In particular, the poster describes the challenges and limitations created by the hardware and the software...

  2. Are altered smooth pursuit eye movements related to chronic pain and disability following whiplash injuries? A prospective trial with one-year follow-up

    DEFF Research Database (Denmark)

    Kongsted, Alice; Jørgensen, Lars Vincents; Leboeuf-Yde, Charlotte

    2008-01-01

    OBJECTIVE: To evaluate the ability of early smooth pursuit testing to predict chronic whiplash-associated disorders, and to study whether the presence of abnormal smooth pursuit eye movements at one-year follow-up is associated with symptoms at that time. DESIGN: Prospective cohort study with one...... collision were determined. RESULTS: Results of early eye movement tests were not associated with the prognosis. Reduced smooth pursuit performance when tested in static cervical rotation at the one-year follow-up was significantly associated with higher neck pain intensity at that time (regression...

  3. Smooth Pursuit of Flicker-Defined Motion

    Science.gov (United States)

    Mulligan, Jeffrey B.; Stevenson, Scott B.

    2014-01-01

    We examined the pursuit response to stimuli defined by space-variant flicker of a dense random dot carrier pattern. On each frame, every element of the pattern could change polarity, with a probability given by a two-dimensional Gaussian distribution. A normal distribution produces a circular region of twinkle, while inverting the distribution results in a spot of static texture in a twinkling surround. In this latter case, the carrier texture could be stationary, or could move with the twinkle modulator, thereby producing first-order motion in the region of the spot. While the twinkle-defined spot produces a strong sensation of motion, the complementary stimulus defined by the absence of twinkle does not, when viewed peripherally, it appears to move in steps even when the generating distribution moves smoothly. We examined pursuit responses to these stimuli using two techniques: 1) the eye movement correlogram, obtained by cross-correlating eye velocity with the velocity of a randomly-moving stimulus; and 2) delayed visual feedback, where transient stabilization of a target can produce spontaneous oscillations of the eye, with a period empirically observed to vary linearly with the applied delay. Both techniques provide an estimate of the internal processing time, which can be as short as 100 milliseconds for a first-order target. Assessed by the correlogram method, the response to flicker-defined motion is delayed by more than 100 milliseconds, and significantly weaker (especially in the vertical dimension). When initially presented in the delayed feedback condition, purely saccadic oscillation is observed. One subject eventually developed smooth oscillations (albeit with significant saccadic intrusions), showing a period-versus-delay slope similar to that observed for first-order targets. This result is somewhat surprising, given that we interpret the slope of the period-versus-delay-function as reflecting the balance between position- and velocity

  4. Accuracy of eye position for saccades and smooth pursuit

    OpenAIRE

    Shanidze, Natela; Ghahghaei, Saeideh; Verghese, Preeti

    2016-01-01

    In this study, we address the question of whether a target is foveated during smooth pursuit. Specifically, we examine whether smooth pursuit eye movements land near the center-of-mass of the target, as is the case for saccades. To that end, we instructed eight untrained, healthy participants to follow moving targets, presented monocularly in a scanning laser ophthalmoscope. Stimuli moved either in a modified step-ramp (smooth pursuit), or made a single step (saccade), stepping 6? from the ce...

  5. The effects of smooth pursuit adaptation on the gain of visuomotor transmission in monkeys

    Directory of Open Access Journals (Sweden)

    Seiji eOno

    2013-12-01

    Full Text Available Smooth pursuit eye movements are supported by visual-motor systems, where visual motion information is transformed into eye movement commands. Adaptation of the visuomotor systems for smooth pursuit is an important factor to maintain pursuit accuracy and high acuity vision. Short-term adaptation of initial pursuit gain can be produced experimentally using by repeated trials of a step-ramp tracking with two different velocities (double-step paradigm that step-up (10–30 °/s or step-down (20–5 °/s. It is also known that visuomotor gain during smooth pursuit is regulated by a dynamic gain control mechanism by showing that eye velocity evoked by a target perturbation during pursuit increases bidirectionally when ongoing pursuit velocity is higher. However, it remains uncertain how smooth pursuit adaptation alters the gain of visuomotor transmission. Therefore, a single cycle of sinusoidal motion (2.5 Hz, ± 10 °/s was introduced during step-ramp tracking pre- and post-adaptation to determine whether smooth pursuit adaptation affects the perturbation response. The results showed that pursuit adaptation had a significant effect on the perturbation response that was specific to the adapted direction. These results indicate that there might be different visuomotor mechanisms between adaptation and dynamic gain control. Furthermore, smooth pursuit adaptation altered not only the gain of the perturbation response, but also the gain slope (regression curve at different target velocities (5, 10 and 15 °/s. Therefore, pursuit adaptation could affect the dynamic regulation of the visuomotor gain at different pursuit velocities.

  6. Smooth pursuit eye movements and schizophrenia: literature review.

    Science.gov (United States)

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

    2014-09-01

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

  7. The effects of dividing attention on smooth pursuit eye tracking.

    Science.gov (United States)

    Hutton, S B; Tegally, D

    2005-06-01

    Attentional processes have traditionally been closely linked to the production of saccadic eye movements, but their role in the control of smooth pursuit eye movements remains unclear. In two experiments we used dual task paradigms to vary the attentional resources available for pursuit eye tracking. In both experiments we found that attentionally demanding secondary tasks impaired smooth pursuit performance, resulting in decreased velocity and increased position error. These findings suggest that attention is important for the maintenance of accurate smooth pursuit, and do not support the hypothesis that pursuit is a relatively automatic function that proceeds optimally in the absence of attentional control. These results add weight to the suggestion that a similar functional architecture underlies both pursuit and saccadic eye movements.

  8. Accuracy of eye position for saccades and smooth pursuit.

    Science.gov (United States)

    Shanidze, Natela; Ghahghaei, Saeideh; Verghese, Preeti

    2016-12-01

    In this study, we address the question of whether a target is foveated during smooth pursuit. Specifically, we examine whether smooth pursuit eye movements land near the center-of-mass of the target, as is the case for saccades. To that end, we instructed eight untrained, healthy participants to follow moving targets, presented monocularly in a scanning laser ophthalmoscope. Stimuli moved either in a modified step-ramp (smooth pursuit), or made a single step (saccade), stepping 6° from the center. Targets were ring-shaped and either 0.6° or 1.7° in diameter. In an additional set of experiments, two participants collected more extensive data on smooth pursuit and saccades for a larger range of target sizes (0.6°, 1.7°, or 4.3°). During pursuit, eyes were rarely placed at target center, even when participants' fixational stability was taken into account. Furthermore, there was a clear tendency for distance from target center to increase with target size. This outcome was in contrast to saccades, where there was no effect of target size across participants. The difference in foveal placement between the two types of eye movements is consistent with their different purposes: closer inspection of the target for saccades versus maintenance of the target in the visual field for smooth pursuit.

  9. Enhanced brain responses to color during smooth-pursuit eye movements.

    Science.gov (United States)

    Chen, Jing; Valsecchi, Matteo; Gegenfurtner, Karl R

    2017-08-01

    Eye movements alter visual perceptions in a number of ways. During smooth-pursuit eye movements, previous studies reported decreased detection threshold for colored stimuli and for high-spatial-frequency luminance stimuli, suggesting a boost in the parvocellular system. The present study investigated the underlying neural mechanism using EEG in human participants. Participants followed a moving target with smooth-pursuit eye movements while steady-state visually evoked potentials (SSVEPs) were elicited by equiluminant red-green flickering gratings in the background. SSVEP responses to colored gratings were 18.9% higher during smooth pursuit than during fixation. There was no enhancement of SSVEPs by smooth pursuit when the flickering grating was defined by luminance instead of color. This result provides physiological evidence that the chromatic response in the visual system is boosted by the execution of smooth-pursuit eye movements in humans. Because the response improvement is thought to be the result of an improved response in the parvocellular system, SSVEPs to equiluminant stimuli could provide a direct test of parvocellular signaling, especially in populations where collecting an explicit behavioral response from the participant is not feasible. NEW & NOTEWORTHY We constantly move our eyes when we explore the world. Eye movements alter visual perception in various ways. The smooth-pursuit eye movements have been shown to boost color sensitivity. We recorded steady-state visually evoked potentials to equiluminant chromatic flickering stimuli and observed increased steady-state visually evoked potentials when participants smoothly pursued a moving target compared with when they maintained fixation. This work provides direct neurophysiological evidence for the parvocellular boost by smooth-pursuit eye movements in humans. Copyright © 2017 the American Physiological Society.

  10. Monocular and binocular smooth pursuit in central field loss.

    Science.gov (United States)

    Shanidze, Natela; Heinen, Stephen; Verghese, Preeti

    2017-12-01

    Macular degeneration results in heterogeneous central field loss (CFL) and often has asymmetrical effects in the two eyes. As such, it is not clear to what degree the movements of the two eyes are coordinated. To address this issue, we examined smooth pursuit quantitatively in CFL participants during binocular viewing and compared it to the monocular viewing case. We also examined coordination of the two eyes during smooth pursuit and how this coordination was affected by interocular ratios of acuity and contrast, as well as CFL-specific interocular differences, such as scotoma sizes and degree of binocular overlap. We hypothesized that the coordination of eye movements would depend on the binocularity of the two eyes. To test our hypotheses, we used a modified step-ramp paradigm, and measured pursuit in both eyes while viewing was binocular, or monocular with the dominant or non-dominant eye. Data for CFL participants and age-matched controls were examined at the group, within-group, and individual levels. We found that CFL participants had a broader range of smooth pursuit gains and a significantly lower correlation between the two eyes, as compared to controls. Across both CFL and control groups, smooth pursuit gain and correlation between the eyes are best predicted by the ratio of contrast sensitivity between the eyes. For the subgroup of participants with measurable stereopsis, both smooth pursuit gain and correlation are best predicted by stereoacuity. Therefore, our results suggest that coordination between the eyes during smooth pursuit depends on binocular cooperation between the eyes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. The Initiation of Smooth Pursuit is Delayed in Anisometropic Amblyopia.

    Science.gov (United States)

    Raashid, Rana Arham; Liu, Ivy Ziqian; Blakeman, Alan; Goltz, Herbert C; Wong, Agnes M F

    2016-04-01

    Several behavioral studies have shown that the reaction times of visually guided movements are slower in people with amblyopia, particularly during amblyopic eye viewing. Here, we tested the hypothesis that the initiation of smooth pursuit eye movements, which are responsible for accurately keeping moving objects on the fovea, is delayed in people with anisometropic amblyopia. Eleven participants with anisometropic amblyopia and 14 visually normal observers were asked to track a step-ramp target moving at ±15°/s horizontally as quickly and as accurately as possible. The experiment was conducted under three viewing conditions: amblyopic/nondominant eye, binocular, and fellow/dominant eye viewing. Outcome measures were smooth pursuit latency, open-loop gain, steady state gain, and catch-up saccade frequency. Participants with anisometropic amblyopia initiated smooth pursuit significantly slower during amblyopic eye viewing (206 ± 20 ms) than visually normal observers viewing with their nondominant eye (183 ± 17 ms, P = 0.002). However, mean pursuit latency in the anisometropic amblyopia group during binocular and monocular fellow eye viewing was comparable to the visually normal group. Mean open-loop gain, steady state gain, and catch-up saccade frequency were similar between the two groups, but participants with anisometropic amblyopia exhibited more variable steady state gain (P = 0.045). This study provides evidence of temporally delayed smooth pursuit initiation in anisometropic amblyopia. After initiation, the smooth pursuit velocity profile in anisometropic amblyopia participants is similar to visually normal controls. This finding differs from what has been observed previously in participants with strabismic amblyopia who exhibit reduced smooth pursuit velocity gains with more catch-up saccades.

  12. Smooth pursuit eye movements in patients with macular degeneration

    OpenAIRE

    Shanidze, Natela; Fusco, Giovanni; Potapchuk, Elena; Heinen, Stephen; Verghese, Preeti

    2016-01-01

    Currently, there are no quantitative studies of smooth pursuit, a behavior attributed to the fovea, in individuals with macular degeneration (MD). We hypothesize that pursuit in MD patients depends on the relative positions of the scotoma and target trajectory. We tested this hypothesis with a scanning laser ophthalmoscope (SLO), which allows for direct visualization of the target on the damaged retina. Monocular microperimetry and eye movements were assessed in eleven individuals with differ...

  13. Smooth pursuit eye movements in patients with macular degeneration.

    Science.gov (United States)

    Shanidze, Natela; Fusco, Giovanni; Potapchuk, Elena; Heinen, Stephen; Verghese, Preeti

    2016-01-01

    Currently, there are no quantitative studies of smooth pursuit, a behavior attributed to the fovea, in individuals with macular degeneration (MD). We hypothesize that pursuit in MD patients depends on the relative positions of the scotoma and target trajectory. We tested this hypothesis with a scanning laser ophthalmoscope (SLO), which allows for direct visualization of the target on the damaged retina. Monocular microperimetry and eye movements were assessed in eleven individuals with differing degrees of MD. Observers were asked to visually track a 1.7° target that moved in one of eight radial directions at 5°/s-6°/s. Consistent with our hypothesis, pursuit metrics depended on whether the target moved into or out of scotoma. Pursuit gains decreased with increasing scotoma extent in the target's heading direction (p = 0.017). Latencies were higher when the scotoma was present along the target trajectory (in either starting or heading directions, p < 0.001). Furthermore, an analysis of retinal position shows that targets fell on the fixational locus nearly 50% of the time. The results suggest that MD patients are capable of smooth pursuit eye movements, but are limited by target trajectory and scotoma characteristics.

  14. The Neural Basis of Smooth Pursuit Eye Movements in the Rhesus Monkey Brain

    Science.gov (United States)

    Ilg, Uwe J.; Thier, Peter

    2008-01-01

    Smooth pursuit eye movements are performed in order to prevent retinal image blur of a moving object. Rhesus monkeys are able to perform smooth pursuit eye movements quite similar as humans, even if the pursuit target does not consist in a simple moving dot. Therefore, the study of the neuronal responses as well as the consequences of…

  15. Anticipatory smooth pursuit eye movements evoked by probabilistic cues.

    Science.gov (United States)

    Santos, Elio M; Kowler, Eileen

    2017-11-01

    Anticipatory smooth eye movements (ASEM; smooth eye movements in the direction of anticipated target motion) are elicited by cues that signal the direction of future target motion with high levels of certainty. Natural cues, however, rarely convey information with perfect certainty, and responses to uncertainty provide insights about how predictive behaviors are generated. Subjects smoothly pursued targets that moved to the right or left with varying cued probabilities. ASEM strength in a given direction increased with the probability level. The type of cue also played a role. ASEM elicited by symbolic visual cues tended to underweight low probabilities and overweight high probabilities. Cues based on memory (varying the proportion of trials with left or right motion) produced the opposite pattern, overweighting low probabilities and underweighting high probabilities. Finally, cues whose perceptual structure depicted the motion path produced a bias in ASEM in the depicted direction that was maintained across levels of cue congruency. The results show that the smooth pursuit system relies on a combination of signals, including memory for recent target motions, interpretation of cues, and prior beliefs about the relationship between the perceptual configuration and the motion path to determine the anticipatory response in the presence of uncertainty.

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

    Science.gov (United States)

    de Brouwer, S; Missal, M; Lefèvre, P

    2001-08-01

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

  17. Smooth Pursuit Saccade Amplitude Modulation During Exposure to Microgravity

    Science.gov (United States)

    Reschke, M. F.; Kozlovskaya, I. B.; Sayenko, D. G.; Sayenko, I.; Somers, J. T.; Paloski, W. H.

    2002-01-01

    Russian investigators have reported changes in pursuit tracking of a vertically moving point stimulus during space flight. Early in microgravity, changes were manifested by decreased eye movement amplitude (undershooting) and the appearance of correction saccades. As the flight progressed, pursuit of the moving point stimulus deteriorated while associated saccadic movements were unchanged. Immediately postflight there was an improved execution of active head movements indicating that the deficiencies in pursuit function noted in microgravity may be of central origin. In contrast, tests of two cosmonauts showed that horizontal and vertical smooth pursuit were unchanged inflight. However, results of corresponding saccadic tasks showed a tendency toward the overshooting of a horizontal target early inflight with high accuracy developing later inflight, accompanied by an increased saccade velocity and a trend toward decreased saccade latency. Based on these equivocal results, we have further investigated the effects of space flight on the smooth pursuit mechanism during and after short duration flight, and postflight on returning MIR crewmembers. Sinusoidal target movement was presented horizontally at frequencies of 0.33 and 1.0 Hz. Subjects were asked to perform two trials for each stimulus combination: (1) moving eyes-only (EO) and (2) moving eyes and head (EH) with the target motion. Peak amplitude was 30 deg for 0.33 Hz trials and 15 deg for the 1.0 Hz trials. The relationship between saccade amplitude and peak velocity were plotted as a main sequence for each phase of flight, and linear regression analysis allowed us to determine the slope of each main sequence plot. The linear slopes were then combined for each flight phase for each individual subject. The main sequence for both EO and EH trials at both the 0.33 and 1.0 Hz frequencies during flight for the short duration flyers showed a reduction in saccade velocity and amplitude when compared to the preflight

  18. Attention is allocated closely ahead of the target during smooth pursuit eye movements: Evidence from EEG frequency tagging.

    Science.gov (United States)

    Chen, Jing; Valsecchi, Matteo; Gegenfurtner, Karl R

    2017-07-28

    It is under debate whether attention during smooth pursuit is centered right on the pursuit target or allocated preferentially ahead of it. Attentional deployment was previously probed using a secondary task, which might have altered attention allocation and led to inconsistent findings. We measured frequency-tagged steady-state visual evoked potentials (SSVEP) to measure attention allocation in the absence of any secondary probing task. The observers pursued a moving dot while stimuli flickering at different frequencies were presented at various locations ahead or behind the pursuit target. We observed a significant increase in EEG power at the flicker frequency of the stimulus in front of the pursuit target, compared to the frequency of the stimulus behind. When testing many different locations, we found that the enhancement was detectable up to about 1.5° ahead during pursuit, but vanished by 3.5°. In a control condition using attentional cueing during fixation, we did observe an enhanced EEG response to stimuli at this eccentricity, indicating that the focus of attention during pursuit is narrower than allowed for by the resolution of the attentional system. In a third experiment, we ruled out the possibility that the SSVEP enhancement was a byproduct of the catch-up saccades occurring during pursuit. Overall, we showed that attention is on average allocated ahead of the pursuit target during smooth pursuit. EEG frequency tagging seems to be a powerful technique that allows for the investigation of attention/perception implicitly when an overt task would be confounding. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. [The comparison of characteristics of smooth pursuit in left-handed and right-handed persons].

    Science.gov (United States)

    Bozhkova, V P; Surovicheva, N S; Nikolaev, D P

    2010-01-01

    The estimation of the smooth pursuit efficiency in healthy young adults by method based on stroboscopic stimulation is given. The influence of manual function asymmetry on smooth pursuit was tested. Subjects were classified as left-handed or right-handed under a well known handedness questionnaire of Annett supplemented by Luria's tests. It was shown that the strong right-handed persons have a high quality of smooth pursuit of stimuli moving horizontally in rightward and leftward directions with the velocities 20 degrees/s and 25 degrees/s. Left-handed persons track similar stimuli, on the average, worse than the strong right-handed ones. It haven't been observed the influence of manual function asymmetry on the dependence of the smooth pursuit efficiency from the moving stimuli direction (left to right or right to left).

  20. Smooth pursuit adaptation (SPA exhibits features useful to compensate changes in the properties of the smooth pursuit eye movement system due to usage.

    Directory of Open Access Journals (Sweden)

    Suryadeep eDash

    2013-10-01

    Full Text Available Smooth-pursuit adaptation (SPA refers to the fact that pursuit gain in the early, still open-loop response phase of the pursuit eye movement can be adjusted based on experience. For instance, if the target moves initially at a constant velocity for approximately 100-200ms and then steps to a higher velocity, subjects learn to up-regulate the pursuit gain associated with the initial target velocity (gain-increase SPA in order to reduce the retinal error resulting from the velocity step. Correspondingly, a step to a lower target velocity leads to a decrease in gain (gain-decrease SPA. In this study we demonstrate that the increase in peak eye velocity during gain-increase SPA is a consequence of expanding the duration of the eye acceleration profile while the decrease in peak velocity during gain-decrease SPA results from reduced peak eye acceleration but unaltered duration. Furthermore, we show that carrying out stereotypical smooth pursuit eye movements elicited by constant velocity target ramps for several hundred trials (= test of pursuit resilience leads to a clear drop in initial peak acceleration, a reflection of oculomotor and/ or cognitive fatigue. However, this drop in acceleration gets compensated by an increase in the duration of the acceleration profile, thereby keeping initial pursuit gain constant. The compensatory expansion of the acceleration profile in the pursuit resilience experiment is reminiscent of the one leading to gain-increase SPA, suggesting that both processes tap one and the same neuronal mechanism warranting a precise acceleration/ duration trade-off. Finally, we show that the ability to adjust acceleration duration during pursuit resilience depends on the integrity of the oculomotor vermis (OMV as indicated by the complete loss of the duration adjustment following a surgical lesion of the OMV in one rhesus monkey we could study.

  1. Vestibular-related frontal cortical areas and their roles in smooth-pursuit eye movements: representation of neck velocity, neck-vestibular interactions and memory-based smooth-pursuit

    Directory of Open Access Journals (Sweden)

    Kikuro eFukushima

    2011-12-01

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

  2. Illusory motion reveals velocity matching, not foveation, drives smooth pursuit of large objects.

    Science.gov (United States)

    Ma, Zheng; Watamaniuk, Scott N J; Heinen, Stephen J

    2017-10-01

    When small objects move in a scene, we keep them foveated with smooth pursuit eye movements. Although large objects such as people and animals are common, it is nonetheless unknown how we pursue them since they cannot be foveated. It might be that the brain calculates an object's centroid, and then centers the eyes on it during pursuit as a foveation mechanism might. Alternatively, the brain merely matches the velocity by motion integration. We test these alternatives with an illusory motion stimulus that translates at a speed different from its retinal motion. The stimulus was a Gabor array that translated at a fixed velocity, with component Gabors that drifted with motion consistent or inconsistent with the translation. Velocity matching predicts different pursuit behaviors across drift conditions, while centroid matching predicts no difference. We also tested whether pursuit can segregate and ignore irrelevant local drifts when motion and centroid information are consistent by surrounding the Gabors with solid frames. Finally, observers judged the global translational speed of the Gabors to determine whether smooth pursuit and motion perception share mechanisms. We found that consistent Gabor motion enhanced pursuit gain while inconsistent, opposite motion diminished it, drawing the eyes away from the center of the stimulus and supporting a motion-based pursuit drive. Catch-up saccades tended to counter the position offset, directing the eyes opposite to the deviation caused by the pursuit gain change. Surrounding the Gabors with visible frames canceled both the gain increase and the compensatory saccades. Perceived speed was modulated analogous to pursuit gain. The results suggest that smooth pursuit of large stimuli depends on the magnitude of integrated retinal motion information, not its retinal location, and that the position system might be unnecessary for generating smooth velocity to large pursuit targets.

  3. Effects of stimulus size and velocity on steady-state smooth pursuit induced by realistic images

    Science.gov (United States)

    Li, Feng; Pelz, Jeff B.; Daly, Scott J.

    2010-02-01

    Smooth pursuit eye movements align the retina with moving targets, ideally stabilizing the retinal image. At a steadystate, eye movements typically reach an approximately constant velocity which depends on, and is usually lower than the target velocity. Experiment 1 investigated the effect of target size and velocity on smooth pursuit induced by realistic images (color photographs of an apple and flower subtending 2° and 17°, respectively), in comparison with a small dot subtending a fraction of a degree. The extended stimuli were found to enhance smooth pursuit gain. Experiment 2 examined the absolute velocity limit of smooth pursuit elicited by the small dot and the effect of the extended targets on the velocity limit. The eye velocity for tracking the dot was found to be saturated at about 63 deg/sec while the saturation velocity occurred at higher velocities for the extended images. The difference in gain due to target size was significant between dot and the two extended stimuli, while no statistical difference exists between an apple and flower stimuli of wider angular extent. Detailed knowledge of the smooth pursuit eye movements is important for several areas of electronic imaging, in particular, assessing perceived motion blur of displayed objects.

  4. Expansion of direction space around the cardinal axes revealed by smooth pursuit eye movements

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    Krukowski, Anton E.; Stone, Leland S.

    2005-01-01

    It is well established that perceptual direction discrimination shows an oblique effect; thresholds are higher for motion along diagonal directions than for motion along cardinal directions. Here, we compare simultaneous direction judgments and pursuit responses for the same motion stimuli and find that both pursuit and perceptual thresholds show similar anisotropies. The pursuit oblique effect is robust under a wide range of experimental manipulations, being largely resistant to changes in trajectory (radial versus tangential motion), speed (10 versus 25 deg/s), directional uncertainty (blocked versus randomly interleaved), and cognitive state (tracking alone versus concurrent tracking and perceptual tasks). Our data show that the pursuit oblique effect is caused by an effective expansion of direction space surrounding the cardinal directions and the requisite compression of space for other directions. This expansion suggests that the directions around the cardinal directions are in some way overrepresented in the visual cortical pathways that drive both smooth pursuit and perception.

  5. A Model of the Smooth Pursuit Eye Movement with Prediction and Learning

    Directory of Open Access Journals (Sweden)

    Davide Zambrano

    2010-01-01

    Full Text Available Smooth pursuit is one of the five main eye movements in humans, consisting of tracking a steadily moving visual target. Smooth pursuit is a good example of a sensory-motor task that is deeply based on prediction: tracking a visual target is not possible by correcting the error between the eye and the target position or velocity with a feedback loop, but it is only possible by predicting the trajectory of the target. This paper presents a model of smooth pursuit based on prediction and learning. It starts from amodel of the neuro-physiological system proposed by Shibata and Schaal (Shibata et al., Neural Networks, vol. 18, pp. 213-224, 2005. The learning component added here decreases the prediction time in the case of target dynamics already experienced by the system. In the implementation described here, the convergence time is, after the learning phase, 0.8 s.

  6. Premotor neurons encode torsional eye velocity during smooth-pursuit eye movements

    Science.gov (United States)

    Angelaki, Dora E.; Dickman, J. David

    2003-01-01

    Responses to horizontal and vertical ocular pursuit and head and body rotation in multiple planes were recorded in eye movement-sensitive neurons in the rostral vestibular nuclei (VN) of two rhesus monkeys. When tested during pursuit through primary eye position, the majority of the cells preferred either horizontal or vertical target motion. During pursuit of targets that moved horizontally at different vertical eccentricities or vertically at different horizontal eccentricities, eye angular velocity has been shown to include a torsional component the amplitude of which is proportional to half the gaze angle ("half-angle rule" of Listing's law). Approximately half of the neurons, the majority of which were characterized as "vertical" during pursuit through primary position, exhibited significant changes in their response gain and/or phase as a function of gaze eccentricity during pursuit, as if they were also sensitive to torsional eye velocity. Multiple linear regression analysis revealed a significant contribution of torsional eye movement sensitivity to the responsiveness of the cells. These findings suggest that many VN neurons encode three-dimensional angular velocity, rather than the two-dimensional derivative of eye position, during smooth-pursuit eye movements. Although no clear clustering of pursuit preferred-direction vectors along the semicircular canal axes was observed, the sensitivity of VN neurons to torsional eye movements might reflect a preservation of similar premotor coding of visual and vestibular-driven slow eye movements for both lateral-eyed and foveate species.

  7. Vertical and horizontal smooth pursuit eye movements in children with developmental coordination disorder.

    Science.gov (United States)

    Robert, Matthieu P; Ingster-Moati, Isabelle; Albuisson, Eliane; Cabrol, Dominique; Golse, Bernard; Vaivre-Douret, Laurence

    2014-06-01

    Our aim was to study horizontal and vertical smooth pursuit eye movements in children with developmental coordination disorder (DCD). Horizontal and vertical smooth pursuit eye movements of 91 children were studied using electro-oculography: 27 children with DCD (23 males, four females), according to the DSM-IV-TR criteria, and 64 comparison children (26 males, 38 females). All children were 7 to 12 years old (mean 9y, SD 1.5y). Among the group of children with DCD, eight had received intervention. Intervention exercised static and dynamic fixation, saccades, visual strategies, visuospatial abilities, and eye-hand coordination. A smooth pursuit gain index was calculated and statistical comparisons were made between the two groups of children. Horizontal pursuit gain was similar in both populations, but vertical pursuit gain was significantly impaired (page as covariate), i.e. more saccadic in children with DCD (18-99%; n=27, mean 51.6%, median 48.5%, SD 23.2%) than in comparison participants (35-97%; n=63, mean 66.4%, median 65.0%, SD 15.4%). Among the DCD group, the vertical pursuit index was also significantly higher (p=0.009) in the intervention subgroup (29-99%; n=8, mean 69.4%, median 75.5%, SD 28.7%) than in the non-intervention subgroup (18-74%; n=19, mean 44.1%, median 42.5%, SD 15.9%). These results suggest a delay in the maturation of the pursuit system in children with DCD. © 2014 Mac Keith Press.

  8. Alcohol impairment of saccadic and smooth pursuit eye movements: impact of risk factors for alcohol dependence.

    Science.gov (United States)

    Roche, Daniel J O; King, Andrea C

    2010-09-01

    While persons at risk for alcohol dependence by virtue of heavy drinking patterns or family history (FH) of alcohol use disorders have exhibited differential alcohol responses on a variety of measures, few studies have examined alcohol's effects on eye movements in these subgroups. The purpose of this study was to (1) conduct a placebo-controlled, dose-ranging study of alcohol's effects on eye movements and (2) examine the impact of these risk factors on oculomotor response to alcohol. A within-subject, double-blind laboratory study was conducted in N = 138 heavy (HD; n = 78) and light social drinkers (LD; n = 60) with self-reported positive (FH+) or negative (FH-) family history. Subjects participated in three laboratory sessions in which they consumed a beverage containing a high (0.8 g/kg) or low (0.4 g/kg) dose of alcohol or placebo. Smooth pursuit, pro-saccadic, and anti-saccadic eye movements were recorded before and at two intervals after alcohol consumption. Alcohol significantly impaired smooth pursuit gain and pro- and anti-saccade latency, velocity, and accuracy in a dose and time specific matter. HD and LD showed similar impairment on smooth pursuit gain and anti-saccade measures, but HD were less impaired in pro-saccade latency, velocity, and accuracy. FH+ and FH- subjects were equally impaired in nearly all pro- and anti-saccade measures, but FH+ were less impaired in smooth pursuit gain. In sum, alcohol produced systematic impairment on oculomotor functioning, even at a non-intoxicating dose. Furthermore, high- and low-risk drinkers may be vulnerable to select performance deficits relative to eye movement task.

  9. Smooth Pursuit Eye Movement Deficits in Patients With Whiplash and Neck Pain are Modulated by Target Predictability.

    Science.gov (United States)

    Janssen, Malou; Ischebeck, Britta K; de Vries, Jurryt; Kleinrensink, Gert-Jan; Frens, Maarten A; van der Geest, Jos N

    2015-10-01

    This is a cross-sectional study. The purpose of this study is to support and extend previous observations on oculomotor disturbances in patients with neck pain and whiplash-associated disorders (WADs) by systematically investigating the effect of static neck torsion on smooth pursuit in response to both predictably and unpredictably moving targets using video-oculography. Previous studies showed that in patients with neck complaints, for instance due to WAD, extreme static neck torsion deteriorates smooth pursuit eye movements in response to predictably moving targets compared with healthy controls. Eye movements in response to a smoothly moving target were recorded with video-oculography in a heterogeneous group of 55 patients with neck pain (including 11 patients with WAD) and 20 healthy controls. Smooth pursuit performance was determined while the trunk was fixed in 7 static rotations relative to the head (from 45° to the left to 45° to right), using both predictably and unpredictably moving stimuli. Patients had reduced smooth pursuit gains and smooth pursuit gain decreased due to neck torsion. Healthy controls showed higher gains for predictably moving targets compared with unpredictably moving targets, whereas patients with neck pain had similar gains in response to both types of target movements. In 11 patients with WAD, increased neck torsion decreased smooth pursuit performance, but only for predictably moving targets. Smooth pursuit of patients with neck pain is affected. The previously reported WAD-specific decline in smooth pursuit due to increased neck torsion seems to be modulated by the predictability of the movement of the target. The observed oculomotor disturbances in patients with WAD are therefore unlikely to be induced by impaired neck proprioception alone. 3.

  10. Pursuit

    Directory of Open Access Journals (Sweden)

    Brian M. Wood

    2015-12-01

    Full Text Available This article describes a software tool called “Pursuit” that is intended to be used for both research and teaching on the topic of optimal foraging theory. The tool provides a dynamic graphical and auditory interface in which users encounter different prey animals and then must decide whether to pursue or ignore the encountered prey. Based on the characteristics of the prey in the foraging environment and the decisions of the player, each user harvests a set of prey per round and achieves a corresponding foraging return rate. Administrators of Pursuit specify the environmental parameters that determine what prey users will encounter. All environmental parameters and user decisions are tracked and logged for analysis. We created this tool for laboratory experiments, but we believe Pursuit could also be an engaging and effective teaching tool, whereby students adopt the role of forager, and through such play, experience a simulated foraging context and learn about foraging theory. Pursuit is freely available and can run on any platform that supports Java, including Mac OS, Windows, and Linux.

  11. Cognitive processes involved in smooth pursuit eye movements: behavioral evidence, neural substrate and clinical correlation

    Directory of Open Access Journals (Sweden)

    Kikuro eFukushima

    2013-03-01

    Full Text Available Smooth-pursuit eye movements allow primates to track moving objects. Efficient pursuit requires appropriate target selection and predictive compensation for inherent processing delays. Prediction depends on expectation of future object motion, storage of motion information and use of extra-retinal mechanisms in addition to visual feedback. We present behavioural evidence of how cognitive processes are involved in predictive pursuit in normal humans and then describe neuronal responses in monkeys and behavioural responses in patients using a new technique to test these cognitive controls. The new technique examines the neural substrate of working memory and movement preparation for predictive pursuit by using a memory-based task in macaque monkeys trained to pursue (go or not pursue (no-go according to a go/no-go cue, in a direction based on memory of a previously presented visual motion display. Single-unit task-related neuronal activity was examined in medial superior temporal cortex (MST, supplementary eye fields (SEF, caudal frontal eye fields (FEF, cerebellar dorsal vermis lobules VI-VII, caudal fastigial nuclei (cFN, and floccular region. Neuronal activity reflecting working memory of visual motion direction and go/no-go selection was found predominantly in SEF, cerebellar dorsal vermis and cFN, whereas movement preparation related signals were found predominantly in caudal FEF and the same cerebellar areas. Chemical inactivation produced effects consistent with differences in signals represented in each area. When applied to patients with Parkinson's disease, the task revealed deficits in movement preparation but not working memory. In contrast, patients with frontal cortical or cerebellar dysfunction had high error rates, suggesting impaired working memory. We show how neuronal activity may be explained by models of retinal and extra-retinal interaction in target selection and predictive control and thus aid understanding of underlying

  12. Smooth pursuit eye movement preferentially facilitates motor-evoked potential elicited by anterior-posterior current in the brain.

    Science.gov (United States)

    Hiraoka, Koichi; Ae, Minori; Ogura, Nana; Komuratani, Sayo; Sano, Chisa; Shiomi, Keigo; Morita, Yuji; Yokoyama, Haruka

    2014-03-26

    Neural interaction between the eye and hand movement centers must be a critical part of the mechanism underlying eye-hand coordination. One of the previous findings supporting this view is smooth pursuit eye movement-induced suppression of motor-evoked potential (MEP) in the hand muscles. The purpose of this study was to determine which descending volleys contributing to MEP are preferentially modulated by smooth pursuit eye movement. MEP in the first dorsal interosseous muscle was elicited by different directions of current in the brain during the steady-state phase of smooth pursuit eye movement. Smooth pursuit eye movement facilitated MEP elicited by anterior-posterior (AP) current, but this effect was not seen in MEP elicited by lateromedial or posterior-anterior current. Latency of MEP elicited by AP current was significantly longer than latencies of MEPs elicited by other directions of current, indicating that AP current in the brain predominantly elicited later I-waves. We conclude that smooth pursuit eye movement in the steady-state phase preferentially facilitates MEP predominantly elicited by later I-waves generated by AP current in the brain.

  13. Normal aging affects movement execution but not visual motion working memory and decision-making delay during cue-dependent memory-based smooth-pursuit.

    Science.gov (United States)

    Fukushima, Kikuro; Barnes, Graham R; Ito, Norie; Olley, Peter M; Warabi, Tateo

    2014-07-01

    Aging affects virtually all functions including sensory/motor and cognitive activities. While retinal image motion is the primary input for smooth-pursuit, its efficiency/accuracy depends on cognitive processes. Elderly subjects exhibit gain decrease during initial and steady-state pursuit, but reports on latencies are conflicting. Using a cue-dependent memory-based smooth-pursuit task, we identified important extra-retinal mechanisms for initial pursuit in young adults including cue information priming and extra-retinal drive components (Ito et al. in Exp Brain Res 229:23-35, 2013). We examined aging effects on parameters for smooth-pursuit using the same tasks. Elderly subjects were tested during three task conditions as previously described: memory-based pursuit, simple ramp-pursuit just to follow motion of a single spot, and popping-out of the correct spot during memory-based pursuit to enhance retinal image motion. Simple ramp-pursuit was used as a task that did not require visual motion working memory. To clarify aging effects, we then compared the results with the previous young subject data. During memory-based pursuit, elderly subjects exhibited normal working memory of cue information. Most movement-parameters including pursuit latencies differed significantly between memory-based pursuit and simple ramp-pursuit and also between young and elderly subjects. Popping-out of the correct spot motion was ineffective for enhancing initial pursuit in elderly subjects. However, the latency difference between memory-based pursuit and simple ramp-pursuit in individual subjects, which includes decision-making delay in the memory task, was similar between the two groups. Our results suggest that smooth-pursuit latencies depend on task conditions and that, although the extra-retinal mechanisms were functional for initial pursuit in elderly subjects, they were less effective.

  14. Effects of ketamine on brain function during smooth pursuit eye movements.

    Science.gov (United States)

    Steffens, M; Becker, B; Neumann, C; Kasparbauer, A M; Meyhöfer, I; Weber, B; Mehta, M A; Hurlemann, R; Ettinger, U

    2016-11-01

    The uncompetitive NMDA receptor antagonist ketamine has been proposed to model symptoms of psychosis. Smooth pursuit eye movements (SPEM) are an established biomarker of schizophrenia. SPEM performance has been shown to be impaired in the schizophrenia spectrum and during ketamine administration in healthy volunteers. However, the neural mechanisms mediating SPEM impairments during ketamine administration are unknown. In a counter-balanced, placebo-controlled, double-blind, within-subjects design, 27 healthy participants received intravenous racemic ketamine (100 ng/mL target plasma concentration) on one of two assessment days and placebo (intravenous saline) on the other. Participants performed a block-design SPEM task during functional magnetic resonance imaging (fMRI) at 3 Tesla field strength. Self-ratings of psychosis-like experiences were obtained using the Psychotomimetic States Inventory (PSI). Ketamine administration induced psychosis-like symptoms, during ketamine infusion, participants showed increased ratings on the PSI dimensions cognitive disorganization, delusional thinking, perceptual distortion and mania. Ketamine led to robust deficits in SPEM performance, which were accompanied by reduced blood oxygen level dependent (BOLD) signal in the SPEM network including primary visual cortex, area V5 and the right frontal eye field (FEF), compared to placebo. A measure of connectivity with V5 and FEF as seed regions, however, was not significantly affected by ketamine. These results are similar to the deviations found in schizophrenia patients. Our findings support the role of glutamate dysfunction in impaired smooth pursuit performance and the use of ketamine as a pharmacological model of psychosis, especially when combined with oculomotor biomarkers. Hum Brain Mapp 37:4047-4060, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. Increased Saccadic Rate during Smooth Pursuit Eye Movements in Patients at Ultra High Risk for Developing a Psychosis

    Science.gov (United States)

    van Tricht, M. J.; Nieman, D. H.; Bour, L. J.; Boeree, T.; Koelman, J. H. T. M.; de Haan, L.; Linszen, D. H.

    2010-01-01

    Abnormalities in eye tracking are consistently observed in schizophrenia patients and their relatives and have been proposed as an endophenotype of the disease. The aim of this study was to investigate the performance of patients at Ultra High Risk (UHR) for developing psychosis on a task of smooth pursuit eye movement (SPEM). Forty-six UHR…

  16. Superior colliculus responses to attended, unattended, and remembered saccade targets during smooth pursuit eye movements.

    Directory of Open Access Journals (Sweden)

    Suryadeep eDash

    2016-04-01

    Full Text Available In realistic environments, keeping track of multiple visual targets during eye movements likely involves an interaction between vision,top-down spatial attention, memory, and self-motion information. Recently we found that the superior colliculus (SC visual memory response is attention-sensitive and continuously updated relative to gaze direction. In that study,animals were trained to remember the location of a saccade target across an intervening smooth pursuit (SP eye movement (Dash et al. 2015. Here, we modified this paradigm to directly compare the properties of visual and memory updating responsesto attended and unattended targets.Our analysis shows that during SP, active SC visual vs. memory updating responses share similar gaze-centered spatio-temporal profiles (suggesting a common mechanism, but updating was weaker by ~25%, delayed by ~55ms, and far more dependent on attention. Further, during SP the sum of passive visual responses (to distracter stimuli and memory updating responses (to saccade targets closely resembled the responses for active attentional tracking of visible saccade targets. These results suggest that SP updating signals provide a damped, delayed estimate of attended location that contributes to the gaze-centered tracking of both remembered and visible saccade targets.

  17. Short-term adaptation of saccades does not affect smooth pursuit eye movement initiation.

    Science.gov (United States)

    Sun, Zongpeng; Smilgin, Aleksandra; Junker, Marc; Dicke, Peter W; Thier, Peter

    2017-08-01

    Scrutiny of the visual environment requires saccades that shift gaze to objects of interest. In case the object should be moving, smooth pursuit eye movements (SPEM) try to keep the image of the object within the confines of the fovea in order to ensure sufficient time for its analysis. Both saccades and SPEM can be adaptively changed by the experience of insufficiencies, compromising the precision of saccades or the minimization of object image slip in the case of SPEM. As both forms of adaptation rely on the cerebellar oculomotor vermis (OMV), most probably deploying a shared neuronal machinery, one might expect that the adaptation of one type of eye movement should affect the kinematics of the other. In order to test this expectation, we subjected two monkeys to a standard saccadic adaption paradigm with SPEM test trials at the end and, alternatively, the same two monkeys plus a third one to a random saccadic adaptation paradigm with interleaved trials of SPEM. In contrast to our expectation, we observed at best marginal transfer which, moreover, had little consistency across experiments and subjects. The lack of consistent transfer of saccadic adaptation decisively constrains models of the implementation of oculomotor learning in the OMV, suggesting an extensive separation of saccade- and SPEM-related synapses on P-cell dendritic trees.

  18. The mindful eye: Smooth pursuit and saccadic eye movements in meditators and non-meditators.

    Science.gov (United States)

    Kumari, Veena; Antonova, Elena; Wright, Bernice; Hamid, Aseel; Hernandez, Eva Machado; Schmechtig, Anne; Ettinger, Ulrich

    2017-02-01

    This study examined the effects of cultivated (i.e. developed through training) and dispositional (trait) mindfulness on smooth pursuit (SPEM) and antisaccade (AS) tasks known to engage the fronto-parietal network implicated in attentional and motion detection processes, and the fronto-striatal network implicated in cognitive control, respectively. Sixty healthy men (19-59years), of whom 30 were experienced mindfulness practitioners and 30 meditation-naïve, underwent infrared oculographic assessment of SPEM and AS performance. Trait mindfulness was assessed using the self-report Five Facet Mindfulness Questionnaire (FFMQ). Meditators, relative to meditation-naïve individuals, made significantly fewer catch-up and anticipatory saccades during the SPEM task, and had significantly lower intra-individual variability in gain and spatial error during the AS task. No SPEM or AS measure correlated significantly with FFMQ scores in meditation-naïve individuals. Cultivated, but not dispositional, mindfulness is associated with improved attention and sensorimotor control as indexed by SPEM and AS tasks. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Sleep deprivation as an experimental model system for psychosis: Effects on smooth pursuit, prosaccades, and antisaccades.

    Science.gov (United States)

    Meyhöfer, Inga; Kumari, Veena; Hill, Antje; Petrovsky, Nadine; Ettinger, Ulrich

    2017-04-01

    Current antipsychotic medications fail to satisfactorily reduce negative and cognitive symptoms and produce many unwanted side effects, necessitating the development of new compounds. Cross-species, experimental behavioural model systems can be valuable to inform the development of such drugs. The aim of the current study was to further test the hypothesis that controlled sleep deprivation is a safe and effective model system for psychosis when combined with oculomotor biomarkers of schizophrenia. Using a randomized counterbalanced within-subjects design, we investigated the effects of 1 night of total sleep deprivation in 32 healthy participants on smooth pursuit eye movements (SPEM), prosaccades (PS), antisaccades (AS), and self-ratings of psychosis-like states. Compared with a normal sleep control night, sleep deprivation was associated with reduced SPEM velocity gain, higher saccadic frequency at 0.2 Hz, elevated PS spatial error, and an increase in AS direction errors. Sleep deprivation also increased intra-individual variability of SPEM, PS, and AS measures. In addition, sleep deprivation induced psychosis-like experiences mimicking hallucinations, cognitive disorganization, and negative symptoms, which in turn had moderate associations with AS direction errors. Taken together, sleep deprivation resulted in psychosis-like impairments in SPEM and AS performance. However, diverging somewhat from the schizophrenia literature, sleep deprivation additionally disrupted PS control. Sleep deprivation thus represents a promising but possibly unspecific experimental model that may be helpful to further improve our understanding of the underlying mechanisms in the pathophysiology of psychosis and aid the development of antipsychotic and pro-cognitive drugs.

  20. Context effects on smooth pursuit and manual interception of a disappearing target.

    Science.gov (United States)

    Kreyenmeier, Philipp; Fooken, Jolande; Spering, Miriam

    2017-07-01

    In our natural environment, we interact with moving objects that are surrounded by richly textured, dynamic visual contexts. Yet most laboratory studies on vision and movement show visual objects in front of uniform gray backgrounds. Context effects on eye movements have been widely studied, but it is less well known how visual contexts affect hand movements. Here we ask whether eye and hand movements integrate motion signals from target and context similarly or differently, and whether context effects on eye and hand change over time. We developed a track-intercept task requiring participants to track the initial launch of a moving object ("ball") with smooth pursuit eye movements. The ball disappeared after a brief presentation, and participants had to intercept it in a designated "hit zone." In two experiments ( n = 18 human observers each), the ball was shown in front of a uniform or a textured background that either was stationary or moved along with the target. Eye and hand movement latencies and speeds were similarly affected by the visual context, but eye and hand interception (eye position at time of interception, and hand interception timing error) did not differ significantly between context conditions. Eye and hand interception timing errors were strongly correlated on a trial-by-trial basis across all context conditions, highlighting the close relation between these responses in manual interception tasks. Our results indicate that visual contexts similarly affect eye and hand movements but that these effects may be short-lasting, affecting movement trajectories more than movement end points. NEW & NOTEWORTHY In a novel track-intercept paradigm, human observers tracked a briefly shown object moving across a textured, dynamic context and intercepted it with their finger after it had disappeared. Context motion significantly affected eye and hand movement latency and speed, but not interception accuracy; eye and hand position at interception were

  1. Altered extracellular magnesium and variations in vascular smooth ...

    African Journals Online (AJOL)

    Altered extracellular magnesium and variations in vascular smooth muscle responses to agonists. ... (5-HT) were examined on 2mm ring segments of the arteries which were suspended in 20 ml organ baths containing physiological salt solution (PSS), for measurement of isometric contractions, at 37oC and pH 7.4.

  2. The effect of apomorphine administration on smooth pursuit ocular movements in early Parkinsonian patients

    Czech Academy of Sciences Publication Activity Database

    Bareš, M.; Brázdil, M.; Kaňovský, P.; Jurák, Pavel; Daniel, P.; Kukleta, M.; Rektor, I.

    2003-01-01

    Roč. 9, č. 3 (2003), s. 139 - 144 ISSN 1353-8020 Institutional research plan: CEZ:AV0Z2065902 Keywords : supplementary eye field * smooth eye movements * Parkinson's disease Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 2.143, year: 2003

  3. Control of the strength of visual-motor transmission as the mechanism of rapid adaptation of priors for Bayesian inference in smooth pursuit eye movements.

    Science.gov (United States)

    Darlington, Timothy R; Tokiyama, Stefanie; Lisberger, Stephen G

    2017-08-01

    Bayesian inference provides a cogent account of how the brain combines sensory information with "priors" based on past experience to guide many behaviors, including smooth pursuit eye movements. We now demonstrate very rapid adaptation of the pursuit system's priors for target direction and speed. We go on to leverage that adaptation to outline possible neural mechanisms that could cause pursuit to show features consistent with Bayesian inference. Adaptation of the prior causes changes in the eye speed and direction at the initiation of pursuit. The adaptation appears after a single trial and accumulates over repeated exposure to a given history of target speeds and directions. The influence of the priors depends on the reliability of visual motion signals: priors are more effective against the visual motion signals provided by low-contrast vs. high-contrast targets. Adaptation of the direction prior generalizes to eye speed and vice versa, suggesting that both priors could be controlled by a single neural mechanism. We conclude that the pursuit system can learn the statistics of visual motion rapidly and use those statistics to guide future behavior. Furthermore, a model that adjusts the gain of visual-motor transmission predicts the effects of recent experience on pursuit direction and speed, as well as the specifics of the generalization between the priors for speed and direction. We suggest that Bayesian inference in pursuit behavior is implemented by distinctly non-Bayesian internal mechanisms that use the smooth eye movement region of the frontal eye fields to control of the gain of visual-motor transmission. NEW & NOTEWORTHY Bayesian inference can account for the interaction between sensory data and past experience in many behaviors. Here, we show, using smooth pursuit eye movements, that the priors based on past experience can be adapted over a very short time frame. We also show that a single model based on direction-specific adaptation of the strength of

  4. Simulated Hypergravity Alters Vascular Smooth Muscle Cell Proliferation and Motility

    Science.gov (United States)

    Hunt, Shameka; Bettis, Barika; Harris-Hooker, Sandra; Sanford, Gary L.

    1997-01-01

    The cellular effects of gravity are poorly understood due to its constancy and nonavailability of altered gravitational models. Such an understanding is crucial for prolonged space flights. In these studies, we assessed the influence of centrifugation at 6G (HGrav) on vascular smooth muscle (SMC) mobility and proliferation. Cells were: (a) plated at low density and subjected to HGrav for 24-72 hr for proliferation studies, or (b) grown to confluency, subjected to HGrav, mechanically denuded and monitored for cell movement into the denuded area. Controls were maintained under normogravity. SMC showed a 50% inhibition of growth under HGrav and 10% serum; HGrav and low serum resulted in greater growth inhibition. The rate of movement of SMC into the denuded area was 2-3-fold higher under HGrav in low serum compared to controls, but similar in 10% serum. These studies show that HGrav has significant effects on SMC growth and mobility, which are dependent on serum levels.

  5. Cyclic GMP alters Ca exchange in vascular smooth muscle

    International Nuclear Information System (INIS)

    Magliola, L.; Bailey, B.; Jones, A.W.

    1986-01-01

    Contraction and 42 K efflux from vascular smooth muscle stimulated either by norepinephrine (NE) or by K-depolarization is dependent on an increase in cytosolic Ca concentration. The purpose of this study was to determine if cyclic GMP (cGMP) inhibited these processes and if inhibition was secondary to the action of cGMP on Ca movements. Basal cGMP content of rat aorta was 1.2 fmol/mg wet wt. Sodium nitroprusside (NP) increased cGMP ∼2-fold at 1 nM and ∼750-fold at 1 μM with no effect on cAMP levels. A 5 min pretreatment with NP (1 μM) completely prevented tension development induced by 3 μM NE. The same concentration of NP also inhibited NE-stimulated 42 K and 45 Ca efflux > 90 and > 80%, respectively. Removal of NP in the continued presence of NE (3 μM) caused recovery of the 42 K efflux response to ∼75% of control with a half-time of ∼2.5 min. NP (1 μM) also caused a rapid relaxation of aorta contracted with 3 μM NE and a loss of the 42 K efflux response with half-times of 2-3 min. In contrast, 100 μM NP produced only a 50% inhibition of contraction induced by high K (55 mM). Also, NP (1 μM) inhibited K-stimulated 42 K efflux only ∼25%. These results demonstrate both a concentration- and a time-dependent relationship between increases in cGMP induced by NP and decreases in NE-stimulated contraction, 42 K and 45 Ca effluxes. They also indicate that the sensitivity of NE-induced contraction and 42 K efflux to NP is greater than that induced by high K. These studies suggest that cGMP modulates the control sites for Ca exchange in the plasma membrane and sarcoplasmic reticulum

  6. EMDR effects on pursuit eye movements.

    Science.gov (United States)

    Kapoula, Zoi; Yang, Qing; Bonnet, Audrey; Bourtoire, Pauline; Sandretto, Jean

    2010-05-21

    This study aimed to objectivize the quality of smooth pursuit eye movements in a standard laboratory task before and after an Eye Movement Desensitization and Reprocessing (EMDR) session run on seven healthy volunteers. EMDR was applied on autobiographic worries causing moderate distress. The EMDR session was complete in 5 out of the 7 cases; distress measured by SUDS (Subjective Units of Discomfort Scale) decreased to a near zero value. Smooth pursuit eye movements were recorded by an Eyelink II video system before and after EMDR. For the five complete sessions, pursuit eye movement improved after their EMDR session. Notably, the number of saccade intrusions-catch-up saccades (CUS)-decreased and, reciprocally, there was an increase in the smooth components of the pursuit. Such an increase in the smoothness of the pursuit presumably reflects an improvement in the use of visual attention needed to follow the target accurately. Perhaps EMDR reduces distress thereby activating a cholinergic effect known to improve ocular pursuit.

  7. Aging-induced alterations in female rat colon smooth muscle: the protective effects of hormonal therapy.

    Science.gov (United States)

    Pascua, P; Camello-Almaraz, C; Pozo, M J; Martin-Cano, F E; Vara, E; Fernández-Tresguerres, J A; Camello, P J

    2012-06-01

    Aging is associated to oxidative damage and alterations in inflammatory and apoptotic pathways. Aging impairs secretion of several hormones, including melatonin and estrogens. However, the mechanisms involved in aging of smooth muscle are poorly known. We have studied the changes induced by aging in the colonic smooth muscle layer of female rats and the protective effect of hormonal therapy. We used young, aged, and ovariectomized aged female rats. Two groups of ovariectomized rats (22 months old) were treated either with melatonin or with estrogen for 10 weeks before sacrifice. Aging induced oxidative imbalance, evidenced by H(2)O(2) accumulation, lipid peroxidation, and decreased catalase activity. The oxidative damage was enhanced by ovariectomy. In addition, aged colonic muscle showed enhanced expression of the pro-inflammatory enzyme cyclooxygenase 2. Expression of the activated forms of caspases 3 and 9 was also enhanced in aged colon. Melatonin and estrogen treatment prevented the oxidative damage and the activation of caspases. In conclusion, aging of colonic smooth muscle induces oxidative imbalance and activation of apoptotic and pro-inflammatory pathways. Hormonal therapy has beneficial effects on the oxidative and apoptotic changes associated to aging in this model.

  8. Mitochondrial Morphofunctional Alterations in Smooth Muscle Cells of Aorta in Rats

    Science.gov (United States)

    Tarán, Mariana; Llorens, Candelaria; Balceda, Ariel; Scribano, María de La Paz; Pons, Patricia; Moya, Mónica

    2014-01-01

    In an experimental model of atherogenesis induced by hyperfibrinogenemia (HF), the pharmacological response of vitamin E was studied in order to assess its antioxidant effect on the mitochondrial morphofunctional alterations in aortic smooth muscle cells. Three groups of male rats were used: (Ctr) control, (AI) atherogenesis induced for 120 days, and (AIE) atherogenesis induced for 120 days and treated with vitamin E. HF was induced by adrenalin injection (0.1 mg/day/rat) for 120 days. AIE group was treated with the administration of 3.42 mg/day/rat of vitamin E for 105 days after the first induction. Mitochondria morphology was analyzed by electronic microscopy (EM) and mitochondrial complexes (MC) by spectrophotometry. In group AI the total and mean number of mitochondria reduced significantly, the intermembranous matrix increased, and swelling was observed with respect to Ctr and AIE (P < 0.01). These damages were related to a significant decrease in the activity of citrate synthase and complexes I, II, III, and IV in group AI in comparison to Ctr (P < 0.001). Similar behavior was presented by group AI compared to AIE (P < 0.001). These results show that vitamin E produces a significative regression of inflammatory and oxidative stress process and it resolved the morphofunctional mitochondrial alterations in this experimental model of atherogenic disease. PMID:24653842

  9. Low androgen induced penile maldevelopment involves altered gene expression of biomarkers of smooth muscle differentiation and a key enzyme regulating cavernous smooth muscle cell tone.

    Science.gov (United States)

    Okumu, Lilian A; Braden, Tim D; Vail, Krystal; Simon, Liz; Goyal, Hari Om

    2014-07-01

    We determined the effects of low androgens in the neonatal period on biomarkers of smooth muscle cell differentiation, Myh11 and Acta2, and on Pde5A expression in the penis. One-day-old pups were treated daily with the gonadotropin-releasing hormone antagonist antide with or without dihydrotestosterone for 1 to 6 days. Tissues were collected at age day 7 and at adulthood at age 120 days. Penes were examined by quantitative reverse transcriptase-polymerase chain reaction, Western blot and immunohistochemistry. Testes were assayed for the intratesticular testosterone and steroidogenic enzymes Cyp17α1 and StAR. Gonadotropin-releasing hormone antagonist exposure suppressed the neonatal testicular testosterone surge 70% to 80%. Quantitative reverse transcriptase-polymerase chain reaction revealed 80% to 90% reductions in Cyp17α1 and StAR protein, and 40% to 60% reductions in Myh11 and ACTA2 as a result of gonadotropin-releasing hormone antagonist compared to controls. Dihydrotestosterone co-administration mitigated these decreases. Western blot confirmed the Myh11 decrease at the protein level. Immunohistochemistry of Acta2 confirmed cavernous smooth muscle cell loss at the tissue level. Also, gonadotropin-releasing hormone antagonist exposure decreased Pde5a expression and dihydrotestosterone co-administration mitigated the decrease. Comparison of data between 2 parts of the penis body (corpora cavernosa and corpus spongiosum) showed that antagonist induced decreases in Myh11, Acta2 and Pde5a expression occurred only in the corpora cavernosa, implying that the latter is the target site of low androgen action. As evidenced by gonadotropin-releasing hormone antagonist induced suppression of the neonatal testosterone surge and reduced steroidogenesis, low androgens in the neonatal period altered gene expression of biomarkers of smooth muscle cell differentiation. This led to loss of cavernous smooth muscle cells and consequently to penile maldevelopment. Copyright

  10. EMDR effects on pursuit eye movements.

    Directory of Open Access Journals (Sweden)

    Zoi Kapoula

    Full Text Available This study aimed to objectivize the quality of smooth pursuit eye movements in a standard laboratory task before and after an Eye Movement Desensitization and Reprocessing (EMDR session run on seven healthy volunteers. EMDR was applied on autobiographic worries causing moderate distress. The EMDR session was complete in 5 out of the 7 cases; distress measured by SUDS (Subjective Units of Discomfort Scale decreased to a near zero value. Smooth pursuit eye movements were recorded by an Eyelink II video system before and after EMDR. For the five complete sessions, pursuit eye movement improved after their EMDR session. Notably, the number of saccade intrusions-catch-up saccades (CUS-decreased and, reciprocally, there was an increase in the smooth components of the pursuit. Such an increase in the smoothness of the pursuit presumably reflects an improvement in the use of visual attention needed to follow the target accurately. Perhaps EMDR reduces distress thereby activating a cholinergic effect known to improve ocular pursuit.

  11. Architecture of a gain controller in the pursuit system.

    Science.gov (United States)

    Keating, E G; Pierre, A

    1996-11-01

    A monkey can pursue faster target oscillations if they appear during ongoing smooth pursuit than if they appear while the monkey is fixating a stationary target. Others have proposed a switch in the pursuit circuit to account for this bistable sensitivity to high frequency targets. It is hypothesized that the switch is closed only during pursuit, permitting the retinal motion signal to pass through the circuit at full gain. Losses in pursuit gain caused by certain cortical lesions do mimic the effect of a switch jammed open. To explore this gain adjustment mechanism further, we measured in monkeys the smooth eye movements in response to a high frequency sinusoidal target (called 'humm') presented under a variety of testing conditions. Pursuit gain measured in response to this humm was not merely bistable. Rather, a graded gain modulation of the pursuit system was possible. Furthermore, the gain adjustment had some directional sensitivity to it, enhancing the response to humm along one axis more than the other. In exploring the factors which gated the gain adjustment, it appeared that the movement of the eyes and not the image motion that occurs during pursuit was paramount for enhancing pursuit gain. Gain was not enhanced by saccadic but only by smooth pursuit tracking movements. Finally, gain could be modulated somewhat by covert signals such as the expectation of future smooth pursuit movements.

  12. Transforming growth factor-beta 3 alters intestinal smooth muscle function: implications for gastroschisis-related intestinal dysfunction.

    Science.gov (United States)

    Moore-Olufemi, S D; Olsen, A B; Hook-Dufresne, D M; Bandla, V; Cox, C S

    2015-05-01

    Gastroschisis (GS) is a congenital abdominal wall defect that results in the development of GS-related intestinal dysfunction (GRID). Transforming growth factor-β, a pro-inflammatory cytokine, has been shown to cause organ dysfunction through alterations in vascular and airway smooth muscle. The purpose of this study was to evaluate the effects of TGF-β3 on intestinal smooth muscle function and contractile gene expression. Archived human intestinal tissue was analyzed using immunohistochemistry and RT-PCR for TGF-β isoforms and markers of smooth muscle gene and micro-RNA contractile phenotype. Intestinal motility was measured in neonatal rats ± TGF-β3 (0.2 and 1 mg/kg). Human intestinal smooth muscle cells (hiSMCs) were incubated with fetal bovine serum ± 100 ng/ml of TGF-β 3 isoforms for 6, 24 and 72 h. The effects of TGF-β3 on motility, hiSMC contractility and hiSMC contractile phenotype gene and micro-RNA expression were measured using transit, collagen gel contraction assay and RT-PCR analysis. Data are expressed as mean ± SEM, ANOVA (n = 6-7/group). GS infants had increased immunostaining of TGF-β3 and elevated levels of micro-RNA 143 & 145 in the intestinal smooth muscle. Rats had significantly decreased intestinal transit when exposed to TGF-β3 in a dose-dependent manner compared with Sham animals. TGF-β3 significantly increased hiSMC gel contraction and contractile protein gene and micro-RNA expression. TGF-β3 contributed to intestinal dysfunction at the organ level, increased contraction at the cellular level and elevated contractile gene expression at the molecular level. A hyper-contractile response may play a role in the persistent intestinal dysfunction seen in GRID.

  13. Montelukast prevents microparticle-induced inflammatory and functional alterations in human bronchial smooth muscle cells.

    Science.gov (United States)

    Fogli, Stefano; Stefanelli, Fabio; Neri, Tommaso; Bardelli, Claudio; Amoruso, Angela; Brunelleschi, Sandra; Celi, Alessandro; Breschi, Maria Cristina

    2013-10-01

    Microparticles (MPs) are membrane fragments that may play a role in the pathogenesis of chronic respiratory diseases. We aimed to investigate whether human monocytes/macrophage-derived MPs could induce a pro-inflammatory phenotype in human bronchial smooth muscle cells (BSMC) and the effect of montelukast in this setting. Experimental methods included isolation of human monocytes/macrophages and generation of monocyte-derived MPs, RT-PCR analysis of gene expression, immunoenzymatic determination of pro-inflammatory factor release, bioluminescent assay of intracellular cAMP levels and electromobility shift assay analysis of NF-κB nuclear translocation. Stimulation of human BSMC with monocyte-derived MPs induced a pro-inflammatory switch in human BSMC by inducing gene expression (COX-2 and IL-8), protein release in the supernatant (PGE2 and IL-8), and heterologous β2-adrenoceptor desensitization. The latter effect was most likely related to autocrine PGE2 since pre-treatment with COX inhibitors restored the ability of salbutamol to induce cAMP synthesis in desensitized cells. Challenge with MPs induced nuclear translocation of NF-κB and selective NF-κB inhibition decreased MP-induced cytokine release in the supernatant. Montelukast treatment prevented IL-8 release and heterologous β2-adrenoceptor desensitization in human BSMC exposed to monocyte-derived MPs by blocking NF-κB nuclear translocation. These findings provide evidence on the role of human monocyte-derived MPs in the airway smooth muscle phenotype switch as a novel potential mechanism in the progression of chronic respiratory diseases and on the protective effects by montelukast in this setting. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Altered Pulmonary Artery Endothelial - Smooth Muscle Cell Interactions in Experimental Congenital Diaphragmatic Hernia

    Science.gov (United States)

    Acker, Shannon N.; Seedorf, Gregory J.; Abman, Steven H.; Nozik-Grayck, Eva; Kuhn, Katherine; Partrick, David A.; Gien, Jason

    2014-01-01

    Background Pulmonary hypertension (PH) secondary to vascular remodeling contributes to poor outcomes in congenital diaphragmatic hernia (CDH), however mechanisms responsible are unknown. We hypothesized that pulmonary artery endothelial cell (PAEC) dysfunction contributes to smooth muscle cell (SMC) hyperplasia in experimental CDH. Methods PAEC and SMC were isolated from fetal sheep with experimental CDH and controls. SMC growth was assessed alone and with SOD plus catalase and during co-culture with control or CDH PAEC with and without ET-1 siRNA transfection. ET-1 protein was measured in PAEC and PASMC lysates and supernatant. ROS production was measured in normal and CDH PAECs with and without ET-1 siRNA. PAEC growth and tube formation were measured with SOD plus catalase. Results CDH SMC growth was decreased and and increased with co-culture with CDH PAEC more than control PAEC. Treatment of CDH PAEC with SOD plus catalase or ET-1 siRNA prevented the increase in SMC growth seen with co-culture. ET-1 protein was increased in CDH PAEC and SMC. ROS production was increased in CDH PAEC and decreased with ET-1 SiRNA. SOD plus catalase restored CDH PAEC growth and tube formation. Conclusions PAEC dysfunction in experimental CDH increases SMC proliferation via ET-1 induced ROS production by PAEC. PMID:25580737

  15. Bitter taste receptor agonists alter mitochondrial function and induce autophagy in airway smooth muscle cells.

    Science.gov (United States)

    Pan, Shi; Sharma, Pawan; Shah, Sushrut D; Deshpande, Deepak A

    2017-07-01

    Airway remodeling, including increased airway smooth muscle (ASM) mass, is a hallmark feature of asthma and COPD. We previously identified the expression of bitter taste receptors (TAS2Rs) on human ASM cells and demonstrated that known TAS2R agonists could promote ASM relaxation and bronchodilation and inhibit mitogen-induced ASM growth. In this study, we explored cellular mechanisms mediating the antimitogenic effect of TAS2R agonists on human ASM cells. Pretreatment of ASM cells with TAS2R agonists chloroquine and quinine resulted in inhibition of cell survival, which was largely reversed by bafilomycin A1, an autophagy inhibitor. Transmission electron microscope studies demonstrated the presence of double-membrane autophagosomes and deformed mitochondria. In ASM cells, TAS2R agonists decreased mitochondrial membrane potential and increased mitochondrial ROS and mitochondrial fragmentation. Inhibiting dynamin-like protein 1 (DLP1) reversed TAS2R agonist-induced mitochondrial membrane potential change and attenuated mitochondrial fragmentation and cell death. Furthermore, the expression of mitochondrial protein BCL2/adenovirus E1B 19-kDa protein-interacting protein 3 (Bnip3) and mitochondrial localization of DLP1 were significantly upregulated by TAS2R agonists. More importantly, inhibiting Bnip3 mitochondrial localization by dominant-negative Bnip3 significantly attenuated cell death induced by TAS2R agonist. Collectively the TAS2R agonists chloroquine and quinine modulate mitochondrial structure and function, resulting in ASM cell death. Furthermore, Bnip3 plays a central role in TAS2R agonist-induced ASM functional changes via a mitochondrial pathway. These findings further establish the cellular mechanisms of antimitogenic effects of TAS2R agonists and identify a novel class of receptors and pathways that can be targeted to mitigate airway remodeling as well as bronchoconstriction in obstructive airway diseases. Copyright © 2017 the American Physiological

  16. Alterations in /sup 28/Mg binding in rabbit aortic smooth muscle

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, G.B.; Shetty, S.S.

    1986-03-01

    The effects of various cations and drugs on /sup 28/Mg movements in the media-intimal layer of rabbit aorta were measured. Muscles were incubated with /sup 28/Mg for at least 90 min to assure sufficient accumulation. The /sup 28/Mg tissue/medium ratio was reduced by two-thirds in the presence of 1.5 mM (added) Mg/sup + +/. The rate of efflux of /sup 28/Mg was not altered by addition of non-radioactive Mg/sup + +/, Ca/sup + +/, Ga/sup + +/ or La/sup + + +/ during washout, but was increased by 0.5 mM EDTA. Uptake of /sup 28/Mg was inhibited substantially by added K/sup +/ (60 mM), neomycin (7 mM), genamicin (4.08 mg/ml), lidocaine (1 mM), Tris (substituted for Na/sup +/) and La/sup + + +/ (1.5 and 15 mM). Substitution of up to 75% of the NaCl present with sucrose resulted in a concentration-dependent increase in /sup 28/Mg uptake (up to more than 7-fold). A transient increase in /sup 28/Mg efflux rate was observed when muscles incubated in sucrose-substituted (for NaCl) Tris solution were exposed to Na/sup +/ (but not when Mg/sup + +/, Ca/sup + +/ or Ga/sup + +/ were added). The results indicate that cellular /sup 28/Mg is slowly accumulated and not readily exchanged. The interactions between NaCl and /sup 28/Mg may involve either an inhibition of Mg/sup + +/ uptake or an enhancement of Mg/sup + +/ efflux in the presence of extracellular NaCl.

  17. Altered expression pattern of molecular factors involved in colonic smooth muscle functions: an immunohistochemical study in patients with diverticular disease.

    Directory of Open Access Journals (Sweden)

    Letizia Mattii

    Full Text Available The pathogenesis of diverticular disease (DD is thought to result from complex interactions among dietary habits, genetic factors and coexistence of other bowel abnormalities. These conditions lead to alterations in colonic pressure and motility, facilitating the formation of diverticula. Although electrophysiological studies on smooth muscle cells (SMCs have investigated colonic motor dysfunctions, scarce attention has been paid to their molecular abnormalities, and data on SMCs in DD are lacking. Accordingly, the main purpose of this study was to evaluate the expression patterns of molecular factors involved in the contractile functions of SMCs in the tunica muscularis of colonic specimens from patients with DD.By means of immunohistochemistry and image analysis, we examined the expression of Cx26 and Cx43, which are prominent components of gap junctions in human colonic SMCs, as well as pS368-Cx43, PKCps, RhoA and αSMA, all known to regulate the functions of gap junctions and the contractile activity of SMCs. The immunohistochemical analysis revealed significant abnormalities in DD samples, concerning both the expression and distribution patterns of most of the investigated molecular factors.This study demonstrates, for the first time, that an altered pattern of factors involved in SMC contractility is present at level of the tunica muscularis of DD patients. Moreover, considering that our analysis was conducted on colonic tissues not directly affected by diverticular lesions or inflammatory reactions, it is conceivable that these molecular alterations may precede and predispose to the formation of diverticula, rather than being mere consequences of the disease.

  18. Altered Expression Pattern of Molecular Factors Involved in Colonic Smooth Muscle Functions: An Immunohistochemical Study in Patients with Diverticular Disease

    Science.gov (United States)

    Mattii, Letizia; Ippolito, Chiara; Segnani, Cristina; Battolla, Barbara; Colucci, Rocchina; Dolfi, Amelio; Bassotti, Gabrio; Blandizzi, Corrado; Bernardini, Nunzia

    2013-01-01

    Background The pathogenesis of diverticular disease (DD) is thought to result from complex interactions among dietary habits, genetic factors and coexistence of other bowel abnormalities. These conditions lead to alterations in colonic pressure and motility, facilitating the formation of diverticula. Although electrophysiological studies on smooth muscle cells (SMCs) have investigated colonic motor dysfunctions, scarce attention has been paid to their molecular abnormalities, and data on SMCs in DD are lacking. Accordingly, the main purpose of this study was to evaluate the expression patterns of molecular factors involved in the contractile functions of SMCs in the tunica muscularis of colonic specimens from patients with DD. Methods and Findings By means of immunohistochemistry and image analysis, we examined the expression of Cx26 and Cx43, which are prominent components of gap junctions in human colonic SMCs, as well as pS368-Cx43, PKCps, RhoA and αSMA, all known to regulate the functions of gap junctions and the contractile activity of SMCs. The immunohistochemical analysis revealed significant abnormalities in DD samples, concerning both the expression and distribution patterns of most of the investigated molecular factors. Conclusion This study demonstrates, for the first time, that an altered pattern of factors involved in SMC contractility is present at level of the tunica muscularis of DD patients. Moreover, considering that our analysis was conducted on colonic tissues not directly affected by diverticular lesions or inflammatory reactions, it is conceivable that these molecular alterations may precede and predispose to the formation of diverticula, rather than being mere consequences of the disease. PMID:23437299

  19. Obesity Induces Artery-Specific Alterations: Evaluation of Vascular Function and Inflammatory and Smooth Muscle Phenotypic Markers

    Directory of Open Access Journals (Sweden)

    Antonio Garcia Soares

    2017-01-01

    Full Text Available Vascular alterations are expected to occur in obese individuals but the impact of obesity could be different depending on the artery type. We aimed to evaluate the obesity effects on the relaxing and contractile responses and inflammatory and smooth muscle (SM phenotypic markers in two vascular beds. Obesity was induced in C57Bl/6 mice by 16-week high-fat diet and vascular reactivity, mRNA expression of inflammatory and SM phenotypic markers, and collagen deposition were evaluated in small mesenteric arteries (SMA and thoracic aorta (TA. Endothelium-dependent relaxation in SMA and TA was not modified by obesity. In contrast, contraction induced by depolarization and contractile agonists was reduced in SMA, whereas only contraction induced by adrenergic agonist was reduced in TA of obese mice. Obesity increased the mRNA expression of pro- and anti-inflammatory cytokines in SMA and TA. The expression of genes necessary for maintaining contractile ability was increased by obesity, but the increase was more pronounced in TA. Collagen deposition was increased in SMA, but not in TA, of obese mice. Although the endothelial function was still preserved, the SM of the two artery types was impaired by obesity, but the impairment was higher in SMA, which could be associated with SM phenotypic changes.

  20. Augmented agonist-induced Ca(2+)-sensitization of coronary artery contraction in genetically hypertensive rats. Evidence for altered signal transduction in the coronary smooth muscle cells.

    Science.gov (United States)

    Satoh, S; Kreutz, R; Wilm, C; Ganten, D; Pfitzer, G

    1994-01-01

    The Ca2+ responsiveness of vascular smooth muscle myofilaments is not unique: it is increased during neuro-humoral activation and decreased during beta-adrenergic stimulation. In this study we tested whether an augmented Ca2+ responsiveness of smooth muscle myofilaments may contribute to the increased coronary tone observed in hypertension using beta-escin-permeabilized coronary arteries from 3-mo-old stroke-prone spontaneously hypertensive rats (SHRSP) and their age matched normotensive reference strain (WKY rats). In intact coronary arteries, the response to 5-hydroxytryptamine (5-HT) but not to KCl was larger in SHRSP than in WKY rats. In beta-escin permeabilized coronary arteries in which the receptor effector coupling is still intact, 5-HT enhanced force at constant submaximal (Ca2+) (pCa 6.38) to a greater extent in SHRSP. The Ca2+ sensitizing effect of 5-HT was mimicked by GTP gamma S (0.01-10 microM); again this effect was larger in SHRSP. In the absence of 5-HT or GTP gamma S the Ca2+ force relation was similar in both groups. Forskolin induced relaxation at constant submaximal (Ca2+). This desensitizing effect was smaller in SHRSP than in WKY rats. In conclusion, this study shows that intracellular signalling pathways involved in modulating the Ca2+ responsiveness of coronary smooth muscle myofilaments are altered in the genetically hypertensive animals favoring a hypercontractile state in the coronary circulation. PMID:7929815

  1. NADPH oxidase 1 deficiency alters caveolin phosphorylation and angiotensin II-receptor localization in vascular smooth muscle.

    Science.gov (United States)

    Basset, Olivier; Deffert, Christine; Foti, Michelangelo; Bedard, Karen; Jaquet, Vincent; Ogier-Denis, Eric; Krause, Karl-Heinz

    2009-10-01

    The superoxide-generating NADPH oxidase NOX1 is thought to be involved in signaling by the angiotensin II-receptor AT1R. However, underlying signaling steps are poorly understood. In this study, we investigated the effect of AngII on aortic smooth muscle from wild-type and NOX1-deficient mice. NOX1-deficient cells showed decreased basal ROS generation and did not produce ROS in response to AngII. Unexpectedly, AngII-dependent Ca(2+) signaling was markedly decreased in NOX1-deficient cells. Immunostaining demonstrated that AT1R was localized on the plasma membrane in wild-type, but intracellularly in NOX1-deficient cells. Immunohistochemistry and immunoblotting showed a decreased expression of AT1R in the aorta of NOX1-deficient mice. To investigate the basis of the abnormal AT1R targeting, we studied caveolin expression and phosphorylation. The amounts of total caveolin and of caveolae were not different in NOX1-deficient mice, but a marked decrease occurred in the phosphorylated form of caveolin. Exogenous H(2)O(2) or transfection of a NOX1 plasmid restored AngII responses in NOX1-deficient cells. Based on these findings, we propose that NOX1-derived reactive oxygen species regulate cell-surface expression of AT1R through mechanisms including caveolin phosphorylation. The lack cell-surface AT1R expression in smooth muscle could be involved in the decreased blood pressure in NOX1-deficient mice.

  2. Fetuin-A and albumin alter cytotoxic effects of calcium phosphate nanoparticles on human vascular smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    Yana Dautova

    Full Text Available Calcification is a detrimental process in vascular ageing and in diseases such as atherosclerosis and arthritis. In particular, small calcium phosphate (CaP crystal deposits are associated with inflammation and atherosclerotic plaque de-stabilisation. We previously reported that CaP particles caused human vascular smooth muscle cell (VSMC death and that serum reduced the toxic effects of the particles. Here, we found that the serum proteins fetuin-A and albumin (≥ 1 µM reduced intracellular Ca2+ elevations and cell death in VSMCs in response to CaP particles. In addition, CaP particles functionalised with fetuin-A, but not albumin, were less toxic than naked CaP particles. Electron microscopic studies revealed that CaP particles were internalised in different ways; via macropinocytosis, membrane invagination or plasma membrane damage, which occurred within 10 minutes of exposure to particles. However, cell death did not occur until approximately 30 minutes, suggesting that plasma membrane repair and survival mechanisms were activated. In the presence of fetuin-A, CaP particle-induced damage was inhibited and CaP/plasma membrane interactions and particle uptake were delayed. Fetuin-A also reduced dissolution of CaP particles under acidic conditions, which may contribute to its cytoprotective effects after CaP particle exposure to VSMCs. These studies are particularly relevant to the calcification observed in blood vessels in patients with kidney disease, where circulating levels of fetuin-A and albumin are low, and in pathological situations where CaP crystal formation outweighs calcification-inhibitory mechanisms.

  3. Whole animal knockout of smooth muscle alpha-actin does not alter excisional wound healing or the fibroblast-to-myofibroblast transition.

    Science.gov (United States)

    Tomasek, James J; Haaksma, Carol J; Schwartz, Robert J; Howard, Eric W

    2013-01-01

    The contractile phenotype and function of myofibroblasts have been proposed to play a critical role in wound closure. It has been hypothesized that smooth muscle α-actin expressed in myofibroblasts is critical for its formation and function. We have used smooth muscle α-actin-null mice to test this hypothesis. Full-thickness excisional wounds closed at a similar rate in smooth muscle α-actin-null and wild-type mice. In addition, fibroblasts in smooth muscle α-actin-null granulation tissue when immunostained with a monoclonal antibody that recognizes all muscle actin isoforms exhibited a myofibroblast-like distribution and a stress fiber-like pattern, showing that these cells acquired the myofibroblast phenotype. Dermal fibroblasts from smooth muscle α-actin-null and wild-type mice formed stress fibers and supermature focal adhesions, and generated similar amounts of contractile force in response to transforming growth factor-β1. Smooth muscle γ-actin and skeletal muscle α-actin were expressed in smooth muscle α-actin-null myofibroblasts, as shown by immunostaining, real-time polymerase chain reaction, and mass spectrometry. These results show that smooth muscle α-actin is not necessary for myofibroblast formation and function and for wound closure, and that smooth muscle γ-actin and skeletal muscle α-actin may be able to functionally compensate for the lack of smooth muscle α-actin in myofibroblasts. © 2012 by the Wound Healing Society.

  4. Up-down asymmetry of cerebellar activation during vertical pursuit eye movements.

    Science.gov (United States)

    Glasauer, Stefan; Stephan, Thomas; Kalla, Roger; Marti, Sarah; Straumann, Dominik

    2009-09-01

    Animal experiments have demonstrated that the vast majority of vertical gaze-velocity Purkinje cells in the cerebellar floccular lobe, whose firing rate is modulated during vertical smooth pursuit eye movements, show a preference for downward pursuit. Here we validate the functional vertical asymmetry of the cerebellar flocculus in humans using functional magnetic resonance imaging by demonstrating a significantly higher activation of the floccular lobe for downward than for upward pursuit. The findings corroborate our recent hypothesis on the pathogenesis of cerebellar downbeat nystagmus.

  5. The Role of Dopamine in Anticipatory Pursuit Eye Movements: Insights from Genetic Polymorphisms in Healthy Adults.

    Science.gov (United States)

    Billino, Jutta; Hennig, Jürgen; Gegenfurtner, Karl R

    2016-01-01

    There is a long history of eye movement research in patients with psychiatric diseases for which dysfunctions of neurotransmission are considered to be the major pathologic mechanism. However, neuromodulation of oculomotor control is still hardly understood. We aimed to investigate in particular the impact of dopamine on smooth pursuit eye movements. Systematic variability in dopaminergic transmission due to genetic polymorphisms in healthy subjects offers a noninvasive opportunity to determine functional associations. We measured smooth pursuit in 110 healthy subjects genotyped for two well-documented polymorphisms, the COMT Val 158 Met polymorphism and the SLC6A3 3'-UTR-VNTR polymorphism. Pursuit paradigms were chosen to particularly assess the ability of the pursuit system to initiate tracking when target motion onset is blanked, reflecting the impact of extraretinal signals. In contrast, when following a fully visible target sensory, retinal signals are available. Our results highlight the crucial functional role of dopamine for anticipatory, but not for sensory-driven, pursuit processes. We found the COMT Val 158 Met polymorphism specifically associated with anticipatory pursuit parameters, emphasizing the dominant impact of prefrontal dopamine activity on complex oculomotor control. In contrast, modulation of striatal dopamine activity by the SLC6A3 3'-UTR-VNTR polymorphism had no significant functional effect. Though often neglected so far, individual differences in healthy subjects provide a promising approach to uncovering functional mechanisms and can be used as a bridge to understanding deficits in patients.

  6. Smooth approximations

    Czech Academy of Sciences Publication Activity Database

    Hájek, Petr Pavel; Johanis, M.

    2010-01-01

    Roč. 259, č. 3 (2010), s. 561-582 ISSN 0022-1236 R&D Projects: GA AV ČR IAA100190801 Institutional research plan: CEZ:AV0Z10190503 Keywords : C-P-smooth * Banach spaces * Lipschitz Subject RIV: BA - General Mathematics Impact factor: 1.196, year: 2010 http://www.sciencedirect.com/science/article/pii/S0022123610001795

  7. Pursuit-evasion differential games

    CERN Document Server

    Yavin, Y

    1987-01-01

    Twenty papers are devoted to the treatment of a wide spectrum of problems in the theory and applications of dynamic games with the emphasis on pursuit-evasion differential games. The problem of capturability is thoroughly investigated, also the problem of noise-corrupted (state) measurements. Attention is given to aerial combat problems and their attendant modelling issues, such as variable speed of the combatants, the three-dimensionality of physical space, and the combat problem, i.e. problems related to 'role determination'.

  8. Highly Scalable Matching Pursuit Signal Decomposition Algorithm

    Data.gov (United States)

    National Aeronautics and Space Administration — In this research, we propose a variant of the classical Matching Pursuit Decomposition (MPD) algorithm with significantly improved scalability and computational...

  9. Multiple predictor smoothing methods for sensitivity analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Helton, Jon Craig; Storlie, Curtis B.

    2006-08-01

    The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described: (1) locally weighted regression (LOESS), (2) additive models, (3) projection pursuit regression, and (4) recursive partitioning regression. The indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present.

  10. The knockout of miR-143 and -145 alters smooth muscle cell maintenance and vascular homeostasis in mice: correlates with human disease

    Science.gov (United States)

    Elia, Leonardo; Quintavalle, Manuela; Zhang, Jianlin; Contu, Riccardo; Cossu, Luca; Latronico, Michael V. G.; Peterson, Kirk L.; Indolfi, Ciro; Catalucci, Daniele; Chen, Ju; Courtneidge, Sara A.; Condorelli, Gianluigi

    2010-01-01

    Mechanisms controlling vascular smooth muscle cell (VSMC) plasticity and renewal still remain to be completely elucidated. A class of small RNAs called microRNAs (miRs) regulate gene expression at the post-transcriptional level. Here we demonstrate a critical role of the miR-143/145 cluster in SMC differentiation and vascular pathogenesis, also through the generation of a mouse model of miR-143 and -145 knockout. We determined that the expression of miR-143 and -145 is decreased in acute and chronic vascular stress (transverse aortic constriction and in aortas of the ApoE knockout mouse). In human aortic aneurysms, the expression of miR-143 and -145 was significantly decreased compared to control aortas. In addition, overexpression of miR-143 and -145 decreased neointimal formation in a rat model of acute vascular injury. An in-depth analysis of the miR-143/145 knockout mouse model demonstrated that this miR cluster is expressed mostly in the SMC compartment, both during development and post-natally, in vessels and SMC-containing organs. Loss of miR-143 and miR-145 expression induces structural modifications of the aorta, due to an incomplete differentiation of VSMCs. In conclusion, our results demonstrate that the miR-143/145 gene cluster plays a critical role during SMC differentiation and strongly suggest its involvement in the reversion of the VSMC differentiation phenotype that occurs during vascular disease. PMID:19816508

  11. Nutritional B vitamin deficiency alters the expression of key proteins associated with vascular smooth muscle cell proliferation and migration in the aorta of atherosclerotic apolipoprotein E null mice.

    Science.gov (United States)

    Duthie, Susan J; Beattie, John H; Gordon, Margaret-J; Pirie, Lynn P; Nicol, Fergus; Reid, Martin D; Duncan, Gary J; Cantlay, Louise; Horgan, Graham; McNeil, Christopher J

    2015-01-01

    Low B vitamin status is linked with human vascular disease. We employed a proteomic and biochemical approach to determine whether nutritional folate deficiency and/or hyperhomocysteinemia altered metabolic processes linked with atherosclerosis in ApoE null mice. Animals were fed either a control fat (C; 4 % w/w lard) or a high-fat [HF; 21 % w/w lard and cholesterol (0/15 % w/w)] diet with different B vitamin compositions for 16 weeks. Aorta tissue was prepared and global protein expression, B vitamin, homocysteine and lipoprotein status measured. Changes in the expression of aorta proteins were detected in response to multiple B vitamin deficiency combined with a high-fat diet (P e.g., fibrinogen, moesin, transgelin, vimentin). Combined B vitamin deficiency induced striking quantitative changes in the expression of aorta proteins in atherosclerotic ApoE null mice. Deregulated expression of these proteins is associated with human atherosclerosis. Cellular pathways altered by B vitamin status included cytoskeletal organisation, cell differentiation and migration, oxidative stress and chronic inflammation. These findings provide new insight into the molecular mechanisms through which B vitamin deficiency may accelerate atherosclerosis.

  12. The pursuit of perfect packing

    CERN Document Server

    Weaire, Denis

    2000-01-01

    In 1998 Thomas Hales dramatically announced the solution of a problem that has long teased eminent mathematicians: what is the densest possible arrangement of identical spheres? The Pursuit of Perfect Packing recounts the story of this problem and many others that have to do with packing things together. The examples are taken from mathematics, physics, biology, and engineering, including the arrangement of soap bubbles in foam, atoms in a crystal, the architecture of the bee''s honeycomb, and the structure of the Giant''s Causeway. Using an informal style and with key references, the book also includes brief accounts of the lives of many of the scientists who devoted themselves to problems of packing over many centuries, together with wry comments on their efforts. It is an entertaining introduction to the field for both specialists and the more general public.

  13. The pursuit of perfect packing

    CERN Document Server

    Weaire, Denis

    2008-01-01

    Coauthored by one of the creators of the most efficient space packing solution, the Weaire-Phelan structure, The Pursuit of Perfect Packing, Second Edition explores a problem of importance in physics, mathematics, chemistry, biology, and engineering: the packing of structures. Maintaining its mathematical core, this edition continues and revises some of the stories from its predecessor while adding several new examples and applications. The book focuses on both scientific and everyday problems ranging from atoms to honeycombs. It describes packing models, such as the Kepler conjecture, Voronoï decomposition, and Delaunay decomposition, as well as actual structure models, such as the Kelvin cell and the Weaire-Phelan structure. The authors discuss numerous historical aspects and provide biographical details on influential contributors to the field, including emails from Thomas Hales and Ken Brakke. With examples from physics, crystallography, engineering, and biology, this accessible and whimsical bo...

  14. Altered energy state reversibly controls smooth muscle contractile function in human saphenous vein during acute hypoxia-reoxygenation: Role of glycogen, AMP-activated protein kinase, and insulin-independent glucose uptake.

    Science.gov (United States)

    Pyla, Rajkumar; Pichavaram, Prahalathan; Fairaq, Arwa; Park, Mary Anne; Kozak, Mark; Kamath, Vinayak; Patel, Vijay S; Segar, Lakshman

    2015-09-01

    Hypoxia is known to promote vasodilation of coronary vessels through several mediators including cardiac-derived adenosine and endothelium-derived prostanoids and nitric oxide. To date, the impact of endogenous glycogen depletion in vascular smooth muscle and the resultant alterations in cellular energy state (e.g., AMP-activated protein kinase, AMPK) on the contractile response to G protein-coupled receptor agonists (e.g., serotonin, 5-HT) has not yet been studied. In the present study, ex vivo exposure of endothelium-denuded human saphenous vein rings to hypoxic and glucose-deprived conditions during KCl-induced contractions for 30 min resulted in a marked depletion of endogenous glycogen by ∼80% (from ∼1.78 μmol/g under normoxia to ∼0.36 μmol/g under hypoxia). Importantly, glycogen-depleted HSV rings, which were maintained under hypoxia/reoxygenation and glucose-deprived conditions, exhibited significant increases in basal AMPK phosphorylation (∼6-fold ↑) and 5-HT-induced AMPK phosphorylation (∼19-fold ↑) with an accompanying suppression of 5-HT-induced maximal contractile response (∼68% ↓), compared with respective controls. Exposure of glycogen-depleted HSV rings to exogenous D-glucose, but not the inactive glucose analogs, prevented the exaggerated increase in 5-HT-induced AMPK phosphorylation and restored 5-HT-induced maximal contractile response. In addition, the ability of exogenous D-glucose to rescue cellular stress and impaired contractile function occurred through GLUT1-mediated but insulin/GLUT4-independent mechanisms. Together, the present findings from clinically-relevant human saphenous vein suggest that the loss of endogenous glycogen in vascular smooth muscle and the resultant accentuation of AMPK phosphorylation by GPCR agonists may constitute a yet another mechanism of metabolic vasodilation of coronary vessels in ischemic heart disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Goal Pursuit in Youth with Chronic Pain

    Directory of Open Access Journals (Sweden)

    Emma Fisher

    2016-11-01

    Full Text Available Children and adolescents frequently experience chronic pain that can disrupt their usual activities and lead to poor physical and emotional functioning. The fear avoidance model of pain with an emphasis on the maladaptive behaviors that lead to activity avoidance has guided research and clinical practice. However, this model does not take into consideration variability in responses to pain, in particular the active pursuit of goals despite pain. This review aims to introduce a novel conceptualization of children’s activity engagement versus avoidance using the framework of goal pursuit. We propose a new model of Goal Pursuit in Pediatric Chronic Pain, which proposes that the child’s experience of pain is modified by child factors (e.g., goal salience, motivation/energy, pain-related anxiety/fear, and self-efficacy and parent factors (e.g., parent expectations for pain, protectiveness behaviors, and parent anxiety, which lead to specific goal pursuit behaviors. Goal pursuit is framed as engagement or avoidance of valued goals when in pain. Next, we recommend that research in youth with chronic pain should be reframed to account for the pursuit of valued goals within the context of pain and suggest directions for future research.

  16. Archie Mafeje and the Pursuit of Endogeny: Against Alterity and ...

    African Journals Online (AJOL)

    seriane.camara

    2009-05-14

    May 14, 2009 ... The Kalela Dance (Mitchell 1956) and Epstein's Politics in an Urban African. Community (Epstein 1958), which both point to ..... (read 'tribes') and venomous beasts… As a matter of fact, I like black mambas lethal as they are and wish Africans could ..... land or watering hole. Significantly, Wolpe misread the ...

  17. Mediators on human airway smooth muscle.

    Science.gov (United States)

    Armour, C; Johnson, P; Anticevich, S; Ammit, A; McKay, K; Hughes, M; Black, J

    1997-01-01

    1. Bronchial hyperresponsiveness in asthma may be due to several abnormalities, but must include alterations in the airway smooth muscle responsiveness and/or volume. 2. Increased responsiveness of airway smooth muscle in vitro can be induced by certain inflammatory cell products and by induction of sensitization (atopy). 3. Increased airway smooth muscle growth can also be induced by inflammatory cell products and atopic serum. 4. Mast cell numbers are increased in the airways of asthmatics and, in our studies, in airway smooth muscle that is sensitized and hyperresponsive. 5. We propose that there is a relationship between mast cells and airway smooth muscle cells which, once an allergic process has been initiated, results in the development of critical features in the lungs in asthma.

  18. Role of Smooth Muscle in Intestinal Inflammation

    Directory of Open Access Journals (Sweden)

    Stephen M Collins

    1996-01-01

    Full Text Available The notion that smooth muscle function is altered in inflammation is prompted by clinical observations of altered motility in patients with inflammatory bowel disease (IBD. While altered motility may reflect inflammation-induced changes in intrinsic or extrinsic nerves to the gut, changes in gut hormone release and changes in muscle function, recent studies have provided in vitro evidence of altered muscle contractility in muscle resected from patients with ulcerative colitis or Crohn’s disease. In addition, the observation that smooth muscle cells are more numerous and prominent in the strictured bowel of IBD patients compared with controls suggests that inflammation may alter the growth of intestinal smooth muscle. Thus, inflammation is associated with changes in smooth muscle growth and contractility that, in turn, contribute to important symptoms of IBD including diarrhea (from altered motility and pain (via either altered motility or stricture formation. The involvement of smooth muscle in this context may be as an innocent bystander, where cells and products of the inflammatory process induce alterations in muscle contractility and growth. However, it is likely that intestinal muscle cells play a more active role in the inflammatory process via the elaboration of mediators and trophic factors, including cytokines, and via the production of collagen. The concept of muscle cells as active participants in the intestinal inflammatory process is a new concept that is under intense study. This report summarizes current knowledge as it relates to these two aspects of altered muscle function (growth and contractility in the inflamed intestine, and will focus on mechanisms underlying these changes, based on data obtained from animal models of intestinal inflammation.

  19. Comparison of Orthogonal Matching Pursuit Implementations

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Christensen, Mads Græsbøll

    2012-01-01

    We study the numerical and computational performance of three implementations of orthogonal matching pursuit: one using the QR matrix decomposition, one using the Cholesky matrix decomposition, and one using the matrix inversion lemma. We find that none of these implementations suffer from numeri...

  20. The Pursuit of Science: Its Motivations

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 4. The Pursuit of Science : Its Motivations. S Chandrasekhar. Reflections Volume 2 Issue 4 April 1997 pp 82-95. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/04/0082-0095. Author Affiliations.

  1. In Pursuit of Land Tenure Security

    NARCIS (Netherlands)

    Dekker, Henri

    2006-01-01

    In Pursuit of Land Tenure Security is a unique book that takes the reader on an international tour of perceptions of land tenure security. It contains an anthology of essays based on contacts with people during assignments in various parts of the world over a period of several years. The essays

  2. The Pursuit of Excellence through Education.

    Science.gov (United States)

    Ferrari, Michel, Ed.

    In this book theorists and researchers present a range of perspectives on how to promote excellence in education, providing an opportunity for expression to those who stress transformation of educational practice and those who emphasize individual abilities. In part 1, The Individual Pursuit of Excellence, the chapters are: (1) Learning from…

  3. Smoothed square well potential

    Energy Technology Data Exchange (ETDEWEB)

    Salamon, P. [Institute for Nuclear Research Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary); Vertse, T. [Institute for Nuclear Research Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary); University of Debrecen, Faculty of Informatics, Debrecen (Hungary)

    2017-07-15

    The classical square well potential is smoothed with a finite range smoothing function in order to get a new simple strictly finite range form for the phenomenological nuclear potential. The smoothed square well form becomes exactly zero smoothly at a finite distance, in contrast to the Woods-Saxon form. If the smoothing range is four times the diffuseness of the Woods-Saxon shape both the central and the spin-orbit terms of the Woods-Saxon shape are reproduced reasonably well. The bound single-particle energies in a Woods-Saxon potential can be well reproduced with those in the smoothed square well potential. The same is true for the complex energies of the narrow resonances. (orig.)

  4. Smoothness of limit functors

    Indian Academy of Sciences (India)

    We show that X is representable by a smooth closed subscheme of X . This result generalizes a theorem of Conrad et al. (Pseudo-reductive groups (2010) Cambridge Univ. Press) where the case when X is an affine smooth group and G G m , S acts as a group automorphisms of X is considered. It also occurs as a special ...

  5. Smoothness of limit functors

    Indian Academy of Sciences (India)

    We show that Xλ is representable by a smooth closed subscheme of X. This result generalizes a theorem of Conrad et al. (Pseudo-reductive groups. (2010) Cambridge Univ. Press) where the case when X is an affine smooth group and. Gm,S acts as a group automorphisms of X is considered. It also occurs as a special case.

  6. Quantum State Smoothing.

    Science.gov (United States)

    Guevara, Ivonne; Wiseman, Howard

    2015-10-30

    Smoothing is an estimation method whereby a classical state (probability distribution for classical variables) at a given time is conditioned on all-time (both earlier and later) observations. Here we define a smoothed quantum state for a partially monitored open quantum system, conditioned on an all-time monitoring-derived record. We calculate the smoothed distribution for a hypothetical unobserved record which, when added to the real record, would complete the monitoring, yielding a pure-state "quantum trajectory." Averaging the pure state over this smoothed distribution yields the (mixed) smoothed quantum state. We study how the choice of actual unraveling affects the purity increase over that of the conventional (filtered) state conditioned only on the past record.

  7. Smooth polyhedral surfaces

    KAUST Repository

    Günther, Felix

    2017-03-15

    Polyhedral surfaces are fundamental objects in architectural geometry and industrial design. Whereas closeness of a given mesh to a smooth reference surface and its suitability for numerical simulations were already studied extensively, the aim of our work is to find and to discuss suitable assessments of smoothness of polyhedral surfaces that only take the geometry of the polyhedral surface itself into account. Motivated by analogies to classical differential geometry, we propose a theory of smoothness of polyhedral surfaces including suitable notions of normal vectors, tangent planes, asymptotic directions, and parabolic curves that are invariant under projective transformations. It is remarkable that seemingly mild conditions significantly limit the shapes of faces of a smooth polyhedral surface. Besides being of theoretical interest, we believe that smoothness of polyhedral surfaces is of interest in the architectural context, where vertices and edges of polyhedral surfaces are highly visible.

  8. Multiple predictor smoothing methods for sensitivity analysis: Description of techniques

    International Nuclear Information System (INIS)

    Storlie, Curtis B.; Helton, Jon C.

    2008-01-01

    The use of multiple predictor smoothing methods in sampling-based sensitivity analyses of complex models is investigated. Specifically, sensitivity analysis procedures based on smoothing methods employing the stepwise application of the following nonparametric regression techniques are described: (i) locally weighted regression (LOESS), (ii) additive models, (iii) projection pursuit regression, and (iv) recursive partitioning regression. Then, in the second and concluding part of this presentation, the indicated procedures are illustrated with both simple test problems and results from a performance assessment for a radioactive waste disposal facility (i.e., the Waste Isolation Pilot Plant). As shown by the example illustrations, the use of smoothing procedures based on nonparametric regression techniques can yield more informative sensitivity analysis results than can be obtained with more traditional sensitivity analysis procedures based on linear regression, rank regression or quadratic regression when nonlinear relationships between model inputs and model predictions are present

  9. Illegitimacy Improves Goal Pursuit in Powerless Individuals

    OpenAIRE

    Willis , Guillermo B.; Guinote , Ana; Rodríguez-Bailón , Rosa

    2009-01-01

    Abstract The effects of power legitimacy on self-regulation during goal pursuit were examined. Study 1 focused on goal-setting and goal-striving. Specifically, it examined how much time legitimate and illegitimate powerless individuals needed to set goals, and how many means they generated to pursue these goals. Study 2 examined persistence in the face of difficulties. Consistently across these studies illegitimacy improved self-regulation in powerless individuals. Illegitimate pow...

  10. Reframing our pursuit of life balance.

    Science.gov (United States)

    Fuentes, David G; Ogden, Rachel R; Ryan-Haddad, Ann; Strang, Aimee F

    2015-04-25

    During our time in the 2013 Academic Leadership Fellows Program, we explored what it takes to achieve life balance through a framework presented in a Harvard Business Review article. In this Statement, we describe 5 different areas from the article that provide infrastructure for reflecting on how we have learned to approach life balance in academia. We also provide brief messages based on this reading and others to help academics' pursuit of life balance.

  11. Sharpen customer service skills with PCRAFT Pursuit.

    Science.gov (United States)

    Dologite, Kimberly A; Willner, Kathleen C; Klepeiss, Debra J; York, Susan A; Cericola, Lisa M

    2003-01-01

    Traditional approaches to teaching customer service skills do not involve participant interaction, nor do they provide a fun and relaxed atmosphere for learning. This article describes the development of PCRAFT Pursuit, an innovative game used to teach customer service skills. The development process began with concerns identified through patient satisfaction surveys. The implementation of this game became an integral component of education to improve customer service skills of staff throughout the hospital network.

  12. Grouping pursuit through a regularization solution surface.

    Science.gov (United States)

    Shen, Xiaotong; Huang, Hsin-Cheng

    2010-06-01

    Extracting grouping structure or identifying homogenous subgroups of predictors in regression is crucial for high-dimensional data analysis. A low-dimensional structure in particular-grouping, when captured in a regression model, enables to enhance predictive performance and to facilitate a model's interpretability Grouping pursuit extracts homogenous subgroups of predictors most responsible for outcomes of a response. This is the case in gene network analysis, where grouping reveals gene functionalities with regard to progression of a disease. To address challenges in grouping pursuit, we introduce a novel homotopy method for computing an entire solution surface through regularization involving a piecewise linear penalty. This nonconvex and overcomplete penalty permits adaptive grouping and nearly unbiased estimation, which is treated with a novel concept of grouped subdifferentials and difference convex programming for efficient computation. Finally, the proposed method not only achieves high performance as suggested by numerical analysis, but also has the desired optimality with regard to grouping pursuit and prediction as showed by our theoretical results.

  13. Human airway smooth muscle

    NARCIS (Netherlands)

    J.C. de Jongste (Johan)

    1987-01-01

    textabstractThe function of airway smooth muscle in normal subjects is not evident. Possible physiological roles include maintenance of optimal regional ventilation/perfusion ratios, reduction of anatomic dead space, stabilisation of cartilaginous bronchi, defense against impurities and, less

  14. Laplacians on smooth distributions

    Science.gov (United States)

    Kordyukov, Yu. A.

    2017-10-01

    Let M be a compact smooth manifold equipped with a positive smooth density μ and let H be a smooth distribution endowed with a fibrewise inner product g. We define the Laplacian Δ_H associated with (H,μ,g) and prove that it gives rise to an unbounded self-adjoint operator in L^2(M,μ). Then, assuming that H generates a singular foliation \\mathscr F, we prove that, for any function \\varphi in the Schwartz space \\mathscr S( R), the operator \\varphi(Δ_H) is a smoothing operator in the scale of longitudinal Sobolev spaces associated with \\mathscr F. The proofs are based on pseudodifferential calculus on singular foliations, which was developed by Androulidakis and Skandalis, and on subelliptic estimates for Δ_H. Bibliography: 35 titles.

  15. Human airway smooth muscle

    OpenAIRE

    Jongste, Johan

    1987-01-01

    textabstractThe function of airway smooth muscle in normal subjects is not evident. Possible physiological roles include maintenance of optimal regional ventilation/perfusion ratios, reduction of anatomic dead space, stabilisation of cartilaginous bronchi, defense against impurities and, less likely, squeezing mucus out of mucous glands and pulling open the alveoli next to the airways1 . Any role of airway smooth muscle is necessarily limited, because an important degree of contraction will l...

  16. Motion perception in motion : how we perceive object motion during smooth pursuit eye movements

    NARCIS (Netherlands)

    Souman, J.L.

    2005-01-01

    Eye movements change the retinal image motion of objects in the visual field. When we make an eye movement, the image of a stationary object will move across the retinae, while the retinal image of an object that we follow with the eyes is approximately stationary. To enable us to perceive motion in

  17. John Hejduk's Pursuit of an Architectural Ethos

    DEFF Research Database (Denmark)

    Søberg, Martin

    2012-01-01

    of architectural drawing; a method which, when approached on a more general and conceptual level, might even have the potential to inform design-based architectural research today. The author argues that the conceptual framework of such a method is not a theoretical pursuit of logos, but more a matter of character......Reflected, artistic practices and design-based research are drastically expanding fields within architectural academia. However, the interest in uniting theory and practice is not entirely new. Just a few decades ago, before a ‘death of theory’ was proclaimed, questions of architectural...

  18. Contributions to Pursuit-Evasion Game Theory

    Science.gov (United States)

    Oyler, Dave Wilson

    This dissertation studies adversarial conflicts among a group of agents moving in the plane, possibly among obstacles, where some agents are pursuers and others are evaders. The goal of the pursuers is to capture the evaders, where capture requires a pursuer to be either co-located with an evader, or in close proximity. The goal of the evaders is to avoid capture. These scenarios, where different groups compete to accomplish conflicting goals, are referred to as pursuit-evasion games, and the agents are called players. Games featuring one pursuer and one evader are analyzed using dominance, where a point in the plane is said to be dominated by a player if that player is able to reach the point before the opposing players, regardless of the opposing players' actions. Two generalizations of the Apollonius circle are provided. One solves games with environments containing obstacles, and the other provides an alternative solution method for the Homicidal Chauffeur game. Optimal pursuit and evasion strategies based on dominance are provided. One benefit of dominance analysis is that it extends to games with many players. Two foundational games are studied; one features multiple pursuers against a single evader, and the other features a single pursuer against multiple evaders. Both are solved using dominance through a reduction to single pursuer, single evader games. Another game featuring competing teams of pursuers is introduced, where an evader cooperates with friendly pursuers to rendezvous before being captured by adversaries. Next, the assumption of complete and perfect information is relaxed, and uncertainties in player speeds, player positions, obstacle locations, and cost functions are studied. The sensitivity of the dominance boundary to perturbations in parameters is provided, and probabilistic dominance is introduced. The effect of information is studied by comparing solutions of games with perfect information to games with uncertainty. Finally, a pursuit law

  19. Pursuit of excellence: A forgotten quest?

    Directory of Open Access Journals (Sweden)

    Mark B Wertheimer

    2018-01-01

    Full Text Available The article explores the current orthodontic landscape with respect to the challenges that affect the pursuit of excellence in the specialty. These challenges include marketing by manufacturing companies, financial pressures, marketplace competition, attaining practice efficiency, new product introduction with limited supporting evidence, attributing greater importance to patient experience than the best approach to treatment, and lack of public education regarding their best interests. Home or DIY treatment, bypassing office visits and the practitioner, have also emerged as a concerning trend with the public not clearly understanding the detrimental consequences that may ensue. An over reliance on technology may override individualized treatment and further compromise treatment results.

  20. High dimensional feature reduction via projection pursuit

    Science.gov (United States)

    Jimenez, Luis; Landgrebe, David

    1994-01-01

    The recent development of more sophisticated remote sensing systems enables the measurement of radiation in many more spectral intervals than previously possible. An example of that technology is the AVIRIS system, which collects image data in 220 bands. As a result of this, new algorithms must be developed in order to analyze the more complex data effectively. Data in a high dimensional space presents a substantial challenge, since intuitive concepts valid in a 2-3 dimensional space to not necessarily apply in higher dimensional spaces. For example, high dimensional space is mostly empty. This results from the concentration of data in the corners of hypercubes. Other examples may be cited. Such observations suggest the need to project data to a subspace of a much lower dimension on a problem specific basis in such a manner that information is not lost. Projection Pursuit is a technique that will accomplish such a goal. Since it processes data in lower dimensions, it should avoid many of the difficulties of high dimensional spaces. In this paper, we begin the investigation of some of the properties of Projection Pursuit for this purpose.

  1. Robust Matching Pursuit Extreme Learning Machines

    Directory of Open Access Journals (Sweden)

    Zejian Yuan

    2018-01-01

    Full Text Available Extreme learning machine (ELM is a popular learning algorithm for single hidden layer feedforward networks (SLFNs. It was originally proposed with the inspiration from biological learning and has attracted massive attentions due to its adaptability to various tasks with a fast learning ability and efficient computation cost. As an effective sparse representation method, orthogonal matching pursuit (OMP method can be embedded into ELM to overcome the singularity problem and improve the stability. Usually OMP recovers a sparse vector by minimizing a least squares (LS loss, which is efficient for Gaussian distributed data, but may suffer performance deterioration in presence of non-Gaussian data. To address this problem, a robust matching pursuit method based on a novel kernel risk-sensitive loss (in short KRSLMP is first proposed in this paper. The KRSLMP is then applied to ELM to solve the sparse output weight vector, and the new method named the KRSLMP-ELM is developed for SLFN learning. Experimental results on synthetic and real-world data sets confirm the effectiveness and superiority of the proposed method.

  2. Generalizing smooth transition autoregressions

    DEFF Research Database (Denmark)

    Chini, Emilio Zanetti

    We introduce a variant of the smooth transition autoregression - the GSTAR model - capable to parametrize the asymmetry in the tails of the transition equation by using a particular generalization of the logistic function. A General-to-Specific modelling strategy is discussed in detail...

  3. Smoothed Complexity Theory

    NARCIS (Netherlands)

    Bläser, Markus; Manthey, Bodo

    Smoothed analysis is a new way of analyzing algorithms introduced by Spielman and Teng. Classical methods like worst-case or average-case analysis have accompanying complexity classes, such as P and Avg-P, respectively. Whereas worst-case or average-case analysis give us a means to talk about the

  4. Aspects of random geometric graphs : Pursuit-evasion and treewidth

    NARCIS (Netherlands)

    Li, A.

    2015-01-01

    In this thesis, we studied two aspects of random geometric graphs: pursuit-evasion and treewidth. We first studied one pursuit-evasion game: Cops and Robbers. This game, which dates back to 1970s, are studied extensively in recent years. We investigate this game on random geometric graphs, and get

  5. Relational consequences of personal goal pursuits.

    Science.gov (United States)

    VanderDrift, Laura E; Agnew, Christopher R

    2014-06-01

    Individuals balance tasks necessary to fulfill personal goals and to maintain their interpersonal relationships. In the current studies, we examined the impact of personal goal pursuits on how individuals process and respond to events in their romantic relationships. In 5 experiments, we examined consequences of motivationally active personal goals for relationships. Results indicated that when individuals focused on pursuing a personal goal, they processed relationship information in an evaluatively polarized (Study 1), one-sided (Study 2) fashion. Relative to those deliberating about a personal goal, those focused on a personal goal reported less willingness to engage in some kinds of pro-relationship behaviors (Study 3) and were more likely to forego an opportunity to improve their relationship (Study 4). We attribute this pattern of findings to processing that shielded the personal goal from goal-irrelevant influence (Study 5). These findings provide a greater understanding of how pursuing a personal goal can undermine relationships.

  6. Revealed smooth nontransitive preferences

    DEFF Research Database (Denmark)

    Keiding, Hans; Tvede, Mich

    2013-01-01

    In the present paper, we are concerned with the behavioural consequences of consumers having nontransitive preference relations. Data sets consist of finitely many observations of price vectors and consumption bundles. A preference relation rationalizes a data set provided that for every observed...... many observations of price vectors, lists of individual incomes and aggregate demands. We apply our main result to characterize market data sets consistent with equilibrium behaviour of pure-exchange economies with smooth nontransitive consumers....... consumption bundle, all strictly preferred bundles are more expensive than the observed bundle. Our main result is that data sets can be rationalized by a smooth nontransitive preference relation if and only if prices can normalized such that the law of demand is satisfied. Market data sets consist of finitely...

  7. Smooth Phase Interpolated Keying

    Science.gov (United States)

    Borah, Deva K.

    2007-01-01

    Smooth phase interpolated keying (SPIK) is an improved method of computing smooth phase-modulation waveforms for radio communication systems that convey digital information. SPIK is applicable to a variety of phase-shift-keying (PSK) modulation schemes, including quaternary PSK (QPSK), octonary PSK (8PSK), and 16PSK. In comparison with a related prior method, SPIK offers advantages of better performance and less complexity of implementation. In a PSK scheme, the underlying information waveform that one seeks to convey consists of discrete rectangular steps, but the spectral width of such a waveform is excessive for practical radio communication. Therefore, the problem is to smooth the step phase waveform in such a manner as to maintain power and bandwidth efficiency without incurring an unacceptably large error rate and without introducing undesired variations in the amplitude of the affected radio signal. Although the ideal constellation of PSK phasor points does not cause amplitude variations, filtering of the modulation waveform (in which, typically, a rectangular pulse is converted to a square-root raised cosine pulse) causes amplitude fluctuations. If a power-efficient nonlinear amplifier is used in the radio communication system, the fluctuating-amplitude signal can undergo significant spectral regrowth, thus compromising the bandwidth efficiency of the system. In the related prior method, one seeks to solve the problem in a procedure that comprises two major steps: phase-value generation and phase interpolation. SPIK follows the two-step approach of the related prior method, but the details of the steps are different. In the phase-value-generation step, the phase values of symbols in the PSK constellation are determined by a phase function that is said to be maximally smooth and that is chosen to minimize the spectral spread of the modulated signal. In this step, the constellation is divided into two groups by assigning, to information symbols, phase values

  8. Smooth functors vs. differential forms

    NARCIS (Netherlands)

    Schreiber, U.; Waldorf, K.

    2011-01-01

    We establish a relation between smooth 2-functors defined on the path 2-groupoid of a smooth manifold and differential forms on this manifold. This relation can be understood as a part of a dictionary between fundamental notions from category theory and differential geometry. We show that smooth

  9. Smoothly Varying Bright Blazars

    Science.gov (United States)

    Van Alfen, Nicholas; Hindman, Lauren; Moody, Joseph Ward; Biancardi, Rochelle; Whipple, Parkes; Gaunt, Caleb

    2018-01-01

    It is becoming increasingly apparent that blazar light can vary sinusoidally with periods of hundreds of days to tens of years. Such behavior is expected of, among other things, jets coming from binary black holes. To look for general variability in lesser-known blazars and AGN, in 2015-2016 we monitored 182 objects with Johnson V-band magnitudes reported as being < 16. In all, this campaign generated 22,000 frames from 2,000 unique pointings. We find that approximately one dozen of these objects show evidence of smooth variability consistent with sinusoidal periods. We report on the entire survey sample, highlighting those that show sinusoidal variations.

  10. Sparse Signal Recovery via ECME Thresholding Pursuits

    Directory of Open Access Journals (Sweden)

    Heping Song

    2012-01-01

    Full Text Available The emerging theory of compressive sensing (CS provides a new sparse signal processing paradigm for reconstructing sparse signals from the undersampled linear measurements. Recently, numerous algorithms have been developed to solve convex optimization problems for CS sparse signal recovery. However, in some certain circumstances, greedy algorithms exhibit superior performance than convex methods. This paper is a followup to the recent paper of Wang and Yin (2010, who refine BP reconstructions via iterative support detection (ISD. The heuristic idea of ISD was applied to greedy algorithms. We developed two approaches for accelerating the ECME iteration. The described algorithms, named ECME thresholding pursuits (EMTP, introduced two greedy strategies that each iteration detects a support set I by thresholding the result of the ECME iteration and estimates the reconstructed signal by solving a truncated least-squares problem on the support set I. Two effective support detection strategies are devised for the sparse signals with components having a fast decaying distribution of nonzero components. The experimental studies are presented to demonstrate that EMTP offers an appealing alternative to state-of-the-art algorithms for sparse signal recovery.

  11. Projection pursuit-based dimensionality reduction

    Science.gov (United States)

    Safavi, Haleh; Chang, Chein-I.

    2008-04-01

    Dimensionality Reduction (DR) has found many applications in hyperspectral image processing, e.g., data compression, endmember extraction. This paper investigates Projection Pursuit (PP)-based data dimensionality reduction where three approaches are developed. One is to use a Projection Index (PI) to produce projection vectors that can be used to generate Projection Index Components (PICs). It is a common practice that PP generally uses random initial conditions to produce PICs. As a result, when the same PP is performed in different times or different users at the same time, the resulting PICs are generally not the same. In order to resolve this issue, two approaches are proposed. One is referred to as PI-based PRioritized PP (PI-PRPP) which uses a PI as a criterion to prioritize PICs that are produced by any component analysis, for example, Principal Components Analysis (PCA) or Independent Component Analysis. The other approach is called Initialization-Driven PP (ID-PP) which specifies an appropriate set of initial conditions that allows PP to not only produce PICs in the same order but also the same PICs regardless of how many times PP is run or who runs the PP.

  12. Mixed projection pursuit-based dimensionality reduction

    Science.gov (United States)

    Safavi, Haleh; Chang, Chein-I.

    2009-05-01

    Projection Pursuit (PP) is a component transform technique which seeks a component whose projection vector points to a direction of interestingness in data space which can be specified by a Projection Index (PI). Two most popular component analysis-based techniques, Principal Components Analysis (PCA), Independent Component Analysis (ICA) can be considered as special cases with their PIs specified by data variance and statistical independency respectively. Despite the fact that various component analysis-based techniques have been used for Dimensionality Reduction (DR) the components are generally generated by a specific technique. Even in the case of PP, the same PI has been used to generate project components. This paper explores the utility of PP in DR where various projection indexes are used for DR in context of PP. It further lays out a general setting for PP-based DR and develops algorithms to perform one dimension reduction at a time by using different PIs. In order to substantiate our findings, experiments are conducted to demonstrate advantages of the PP with mixed PIs-based DR over traditional PCA-based, ICA-based and PP-based DR techniques.

  13. Smooth functions statistics

    International Nuclear Information System (INIS)

    Arnold, V.I.

    2006-03-01

    To describe the topological structure of a real smooth function one associates to it the graph, formed by the topological variety, whose points are the connected components of the level hypersurface of the function. For a Morse function, such a graph is a tree. Generically, it has T triple vertices, T + 2 endpoints, 2T + 2 vertices and 2T + 1 arrows. The main goal of the present paper is to study the statistics of the graphs, corresponding to T triple points: what is the growth rate of the number φ(T) of different graphs? Which part of these graphs is representable by the polynomial functions of corresponding degree? A generic polynomial of degree n has at most (n - 1) 2 critical points on R 2 , corresponding to 2T + 2 = (n - 1) 2 + 1, that is to T = 2k(k - 1) saddle-points for degree n = 2k

  14. Scaling of smooth anticipatory eye velocity in response to sequences of discrete target movements in humans.

    Science.gov (United States)

    Collins, C J S; Barnes, G R

    2005-12-01

    We investigated the ability to generate anticipatory smooth pursuit to sequences of constant velocity (ramp) stimuli of increasing complexity. Previously, it was shown that repeated presentation of sequences composed of four ramps with two speeds in two directions, evoked anticipatory smooth pursuit after only one or two presentations. Here, sequences of four or six ramps, each having a choice of four speeds and either one or two directions (uni- or bi-directional) were examined. The components of each sequence were presented as discrete ramps (duration: 400 ms; randomised velocity: 10-40 degrees/s), each starting from the centre with 1,200 ms periods of central fixation between ramps, allowing anticipatory activity to be segregated from prior eye movement. Auditory warning cues occurred 600 ms prior to each target presentation. Anticipatory smooth eye velocity was assessed by calculating eye velocity 50 ms after target onset (V 50), prior to the availability of visual feedback. Despite being required to re-fixate centre during inter-ramp gaps, subjects could still generate anticipatory smooth pursuit with V 50 comparable to single speed control sequences, but with less accuracy. In the steady state V 50 was appropriately scaled in proportion to upcoming target velocity for each ramp component and thus truly predictive. Only one to two repetitions were required to attain a steady-state for unidirectional sequences (four or six ramps), but three or four repeats were required for bi-directional sequences. Results suggest working memory can be used to acquire multiple levels of velocity information for prediction, but its use in rapid prediction is compromised when direction as well as speed must be retained.

  15. Smoothness in Binomial Edge Ideals

    Directory of Open Access Journals (Sweden)

    Hamid Damadi

    2016-06-01

    Full Text Available In this paper we study some geometric properties of the algebraic set associated to the binomial edge ideal of a graph. We study the singularity and smoothness of the algebraic set associated to the binomial edge ideal of a graph. Some of these algebraic sets are irreducible and some of them are reducible. If every irreducible component of the algebraic set is smooth we call the graph an edge smooth graph, otherwise it is called an edge singular graph. We show that complete graphs are edge smooth and introduce two conditions such that the graph G is edge singular if and only if it satisfies these conditions. Then, it is shown that cycles and most of trees are edge singular. In addition, it is proved that complete bipartite graphs are edge smooth.

  16. Multiagent Cooperative Learning Strategies for Pursuit-Evasion Games

    Directory of Open Access Journals (Sweden)

    Jong Yih Kuo

    2015-01-01

    Full Text Available This study examines the pursuit-evasion problem for coordinating multiple robotic pursuers to locate and track a nonadversarial mobile evader in a dynamic environment. Two kinds of pursuit strategies are proposed, one for agents that cooperate with each other and the other for agents that operate independently. This work further employs the probabilistic theory to analyze the uncertain state information about the pursuers and the evaders and uses case-based reasoning to equip agents with memories and learning abilities. According to the concepts of assimilation and accommodation, both positive-angle and bevel-angle strategies are developed to assist agents in adapting to their environment effectively. The case study analysis uses the Recursive Porous Agent Simulation Toolkit (REPAST to implement a multiagent system and demonstrates superior performance of the proposed approaches to the pursuit-evasion game.

  17. Relative Effects of Forward and Backward Planning on Goal Pursuit.

    Science.gov (United States)

    Park, Jooyoung; Lu, Fang-Chi; Hedgcock, William M

    2017-11-01

    Considerable research has shown that planning plays an important role in goal pursuit. But how does the way people plan affect goal pursuit? Research on this question is scarce. In the current research, we examined how planning the steps required for goal attainment in chronological order (i.e., forward planning) and reverse chronological order (i.e., backward planning) influences individuals' motivation for and perceptions of goal pursuit. Compared with forward planning, backward planning not only led to greater motivation, higher goal expectancy, and less time pressure but also resulted in better goal-relevant performance. We further demonstrated that this motivational effect occurred because backward planning allowed people to think of tasks required to reach their goals more clearly, especially when goals were complex to plan. These findings suggest that the way people plan matters just as much as whether or not they plan.

  18. Nearly Cyclic Pursuit and its Hierarchical variant for Multi-agent Systems

    DEFF Research Database (Denmark)

    Iqbal, Muhammad; Leth, John-Josef; Ngo, Trung Dung

    2015-01-01

    The rendezvous problem for multiple agents under nearly cyclic pursuit and hierarchical nearly cyclic pursuit is discussed in this paper. The control law designed under nearly cyclic pursuit strategy enables the agents to converge at a point dictated by a beacon. A hierarchical version of the nea......The rendezvous problem for multiple agents under nearly cyclic pursuit and hierarchical nearly cyclic pursuit is discussed in this paper. The control law designed under nearly cyclic pursuit strategy enables the agents to converge at a point dictated by a beacon. A hierarchical version...

  19. Innovation Pursuit: A New Approach to Subspace Clustering

    Science.gov (United States)

    Rahmani, Mostafa; Atia, George K.

    2017-12-01

    In subspace clustering, a group of data points belonging to a union of subspaces are assigned membership to their respective subspaces. This paper presents a new approach dubbed Innovation Pursuit (iPursuit) to the problem of subspace clustering using a new geometrical idea whereby subspaces are identified based on their relative novelties. We present two frameworks in which the idea of innovation pursuit is used to distinguish the subspaces. Underlying the first framework is an iterative method that finds the subspaces consecutively by solving a series of simple linear optimization problems, each searching for a direction of innovation in the span of the data potentially orthogonal to all subspaces except for the one to be identified in one step of the algorithm. A detailed mathematical analysis is provided establishing sufficient conditions for iPursuit to correctly cluster the data. The proposed approach can provably yield exact clustering even when the subspaces have significant intersections. It is shown that the complexity of the iterative approach scales only linearly in the number of data points and subspaces, and quadratically in the dimension of the subspaces. The second framework integrates iPursuit with spectral clustering to yield a new variant of spectral-clustering-based algorithms. The numerical simulations with both real and synthetic data demonstrate that iPursuit can often outperform the state-of-the-art subspace clustering algorithms, more so for subspaces with significant intersections, and that it significantly improves the state-of-the-art result for subspace-segmentation-based face clustering.

  20. Feature extraction of hyperspectral images using wavelet and matching pursuit

    Science.gov (United States)

    Hsu, Pai-Hui

    Since hyperspectral images contain rich and fine spectral information, an improvement of land use/cover classification accuracy is highly expected from the utilization of such images. However, the traditional statistics-based classification methods which have been successfully applied to multispectral data in the past are not as effective as to hyperspectral data. One major reason is that the number of spectral bands is too large relative to the number of training samples. This problem is caused by curse of dimensionality, which refers to the fact that the sample size required for training a specific classifier grows exponentially with the number of spectral bands. A simple but sometimes very effective way to overcome this problem is to reduce the dimensionality of hyperspectral images. This can be done by feature extraction that a small number of salient features are extracted from the hyperspectral data when confronted with a limited size of training samples. In this paper, a new feature extraction method based on the matching pursuit (MP) is proposed to extract useful features for the classification of hyperspectral images. The matching pursuit algorithm uses a greedy strategy to find an adaptive and optimal representation of the hyperspectral data iteratively from a highly redundant wavelet packets dictionary. An AVIRIS data set was tested to illustrate the classification performance after matching pursuit method was applied. In addition, some existing feature extraction methods based on the wavelet transform are also compared with the matching pursuit method in terms of the classification accuracies. The experiment results showed that the wavelet and matching pursuit method exactly provide an effective tool for feature extraction. The classification problem caused by curse of dimensionality can be avoided by matching pursuit and wavelet-based dimensionality reduction.

  1. Chases and escapes the mathematics of pursuit and evasion

    CERN Document Server

    Nahin, Paul J

    2012-01-01

    We all played tag when we were kids. What most of us don't realize is that this simple chase game is in fact an application of pursuit theory, and that the same principles of games like tag, dodgeball, and hide-and-seek are also at play in military strategy, high-seas chases by the Coast Guard, and even romantic pursuits. In Chases and Escapes, Paul Nahin gives us the first complete history of this fascinating area of mathematics, from its classical analytical beginnings to the present day. Drawing on game theory, geometry, linear algebra, target-tracking algorithms, and much

  2. Very smooth points of spaces of operators

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    ball has a very smooth point then the space has the Radon–Nikodým property. We give an example of a smooth Banach space without any very smooth points. Keywords. Very smooth points; spaces of operators; M-ideals. 1. Introduction. A Banach space X is said to be very smooth if every unit vector has a unique norming.

  3. Smooth analysis in Banach spaces

    CERN Document Server

    Hájek, Petr

    2014-01-01

    This bookis aboutthe subject of higher smoothness in separable real Banach spaces.It brings together several angles of view on polynomials, both in finite and infinite setting.Also a rather thorough and systematic view of the more recent results, and the authors work is given. The book revolves around two main broad questions: What is the best smoothness of a given Banach space, and its structural consequences? How large is a supply of smooth functions in the sense of approximating continuous functions in the uniform topology, i.e. how does the Stone-Weierstrass theorem generalize into in

  4. Comparison of Predictable Smooth Ocular and Combined Eye-Head Tracking Behaviour in Patients with Lesions Affecting the Brainstem and Cerebellum

    Science.gov (United States)

    Grant, Michael P.; Leigh, R. John; Seidman, Scott H.; Riley, David E.; Hanna, Joseph P.

    1992-01-01

    We compared the ability of eight normal subjects and 15 patients with brainstem or cerebellar disease to follow a moving visual stimulus smoothly with either the eyes alone or with combined eye-head tracking. The visual stimulus was either a laser spot (horizontal and vertical planes) or a large rotating disc (torsional plane), which moved at one sinusoidal frequency for each subject. The visually enhanced Vestibulo-Ocular Reflex (VOR) was also measured in each plane. In the horizontal and vertical planes, we found that if tracking gain (gaze velocity/target velocity) for smooth pursuit was close to 1, the gain of combined eye-hand tracking was similar. If the tracking gain during smooth pursuit was less than about 0.7, combined eye-head tracking was usually superior. Most patients, irrespective of diagnosis, showed combined eye-head tracking that was superior to smooth pursuit; only two patients showed the converse. In the torsional plane, in which optokinetic responses were weak, combined eye-head tracking was much superior, and this was the case in both subjects and patients. We found that a linear model, in which an internal ocular tracking signal cancelled the VOR, could account for our findings in most normal subjects in the horizontal and vertical planes, but not in the torsional plane. The model failed to account for tracking behaviour in most patients in any plane, and suggested that the brain may use additional mechanisms to reduce the internal gain of the VOR during combined eye-head tracking. Our results confirm that certain patients who show impairment of smooth-pursuit eye movements preserve their ability to smoothly track a moving target with combined eye-head tracking.

  5. Automatic Epileptic Seizure Onset Detection Using Matching Pursuit

    DEFF Research Database (Denmark)

    Sorensen, Thomas Lynggaard; Olsen, Ulrich L.; Conradsen, Isa

    2010-01-01

    An automatic alarm system for detecting epileptic seizure onsets could be of great assistance to patients and medical staff. A novel approach is proposed using the Matching Pursuit algorithm as a feature extractor combined with the Support Vector Machine (SVM) as a classifier for this purpose...

  6. Avoidance goal pursuit depletes self-regulatory resources

    NARCIS (Netherlands)

    Oertig, Daniela; Schüler, Julia; Schnelle, Jessica; Brandstätter, Veronika; Roskes, Marieke; Elliot, Andrew J.

    Objective: Research on the strength model of self-regulation is burgeoning, but little empirical work has focused on the link between distinct types of daily goal pursuit and the depletion of self-regulatory resources. The authors conducted two studies on the link between avoidance goals and

  7. Avoidance goal pursuit depletes self-regulatory resources

    NARCIS (Netherlands)

    Oertig, D.; Schüler, J.; Schnelle, J.; Brandstätter, V.; Roskes, M.; Elliot, A.J.

    2013-01-01

    Objective: Research on the strength model of self-regulation is burgeoning, but little empirical work has focused on the link between distinct types of daily goal pursuit and the depletion of self-regulatory resources. Here we conducted two studies on the link between avoidance goals and resource

  8. Exercise participation and diet monitoring in pursuit of healthy aging ...

    African Journals Online (AJOL)

    This study examined the level of exercise participation and diet monitoring in pursuit of healthy aging. Descriptive survey research design and self-structured questionnaire was used to elicit information from the respondents. Proportionate stratified and simple random sampling techniques were used to select two hundred ...

  9. Judicial Reform Pursuits in Ethiopia, 2002-2015: Steady Concrete ...

    African Journals Online (AJOL)

    As these problems still persist, I argue that future judicial reform pursuits require a new path which facilitates court-level and institution-level reform through grassroots empowerment including enhanced independence and resource allocation. Subject to justice sector reform harmonization, there should be an independent ...

  10. Narcissism and the Strategic Pursuit of Short-Term Mating

    DEFF Research Database (Denmark)

    Schmitt, David P.; Alcalay, Lidia; Allik, Jüri

    2017-01-01

    Previous studies have documented links between sub-clinical narcissism and the active pursuit of short-term mating strategies (e.g., unrestricted sociosexuality, marital infidelity, mate poaching). Nearly all of these investigations have relied solely on samples from Western cultures. In the curr...

  11. Visual and Kinesthetic Components of Pursuit-Tracking Performance.

    Science.gov (United States)

    Thorsheim, Howard I.; And Others

    Seventy-five subjects were trained on a pursuit rotor for 10 trials, with ambient illumination from a strobe light flashing at frequencies of either 2,5,10,15, or 20 per second. A transfer trial followed, with a strobe flashing frequency of 10 per second for all subjects. Results supported hypotheses derived from Adams' closed-loop theory of motor…

  12. Sparsely-Packetized Predictive Control by Orthogonal Matching Pursuit

    DEFF Research Database (Denmark)

    Nagahara, Masaaki; Quevedo, Daniel; Østergaard, Jan

    2012-01-01

    We study packetized predictive control, known to be robust against packet dropouts in networked systems. To obtain sparse packets for rate-limited networks, we design control packets via an ℓ0 optimization, which can be eectively solved by orthogonal matching pursuit. Our formulation ensures asym...

  13. The unconscious and conscious foundations of human reward pursuit

    NARCIS (Netherlands)

    Bijleveld, E.

    2012-01-01

    Human reward pursuit is often found to be governed by conscious assessments of expected value and required effort. Yet, research also indicates that rewards are initially valuated and processed outside awareness, using rudimentary brain structures. Building on both findings, a new framework is

  14. In Pursuit of Excellence in Teaching: An ESL Educator's Narrative

    Science.gov (United States)

    Barr, Sheldon; Clark, M. Carolyn

    2012-01-01

    This is an educator's story about the pursuit of excellence in teaching. The narrative of an ESL teacher is examined using the analysis tool, Burke's Pentad (Burke 1945). This qualitative examination considers contributing factors of teacher self-efficacy and agency connected with the development, implementation, and sustenance of exemplary…

  15. Responsible Action Research for the Pursuit of Justice

    Science.gov (United States)

    Feldman, Allan; Bennett, Kory; Vernaza-Hernández, Vanessa

    2015-01-01

    The pursuit of justice has concerned human beings for centuries and, despite its importance, often remains outside the boundaries of our educational systems. This article reports on a study of an action research seminar for a group of teacher leaders in a position to instigate positive change within their educational context, and make their…

  16. Positive affect as informational feedback in goal pursuit

    NARCIS (Netherlands)

    Orehek, Edward; Bessarabova, Elena; Chen, Xiaoyan; Kruglanski, Arie W.

    Two studies investigated the cognitive activation of a goal following a promise to complete it. Current theorizing about the impact of positive affect as informational feedback in goal pursuit suggests two contradictory conclusions: (1) positive affect can signal that sufficient progress towards a

  17. Sense of place in outdoor-pursuits trip groups

    Science.gov (United States)

    Sharon L. Todd; Anderson B. Young; Lynn S. Anderson; Timothy S. O' Connell; Mary Breunig

    2009-01-01

    Studies have revealed that sense of community and group cohesion increase significantly over time in outdoor-pursuits trip groups. This study sought to understand similar development of sense of place. Do people simultaneously become more attached to or dependent on the natural environment as they grow closer to each other? Results from a study of college students...

  18. On the Significance of Demand and Inventory Smoothing Interventions in Supply Chain

    NARCIS (Netherlands)

    Cannella, S.; Ciancimino, E.; Ashayeri, J.

    2010-01-01

    The aim of this paper is to quantify the benefit of demand and inventory smoothing in contrasting the extreme volatility and impetuous alteration of the market produced by the current economic recession. To do so we model a traditional supply chain and we test five settings of order smoothing under

  19. Chaotic behaviour from smooth and non-smooth optical solitons ...

    Indian Academy of Sciences (India)

    2016-07-14

    Jul 14, 2016 ... obtain the preferable media to reduce the influ- ence of perturbation of solitons in optical fibre propagation. This paper is organized as follows. In §2, we give the smooth and compacton solitons of the perturbation system by phase diagram analysis. In §3, we discuss the chaotic behaviour of the perturbed ...

  20. Smoothing quadratic and cubic splines

    OpenAIRE

    Oukropcová, Kateřina

    2014-01-01

    Title: Smoothing quadratic and cubic splines Author: Kateřina Oukropcová Department: Department of Numerical Mathematics Supervisor: RNDr. Václav Kučera, Ph.D., Department of Numerical Mathematics Abstract: The aim of this bachelor thesis is to study the topic of smoothing quadratic and cubic splines on uniform partitions. First, we define the basic con- cepts in the field of splines, next we introduce interpolating splines with a focus on their minimizing properties for odd degree and quadra...

  1. Landmine detection using two-tapped joint orthogonal matching pursuits

    Science.gov (United States)

    Goldberg, Sean; Glenn, Taylor; Wilson, Joseph N.; Gader, Paul D.

    2012-06-01

    Joint Orthogonal Matching Pursuits (JOMP) is used here in the context of landmine detection using data obtained from an electromagnetic induction (EMI) sensor. The response from an object containing metal can be decomposed into a discrete spectrum of relaxation frequencies (DSRF) from which we construct a dictionary. A greedy iterative algorithm is proposed for computing successive residuals of a signal by subtracting away the highest matching dictionary element at each step. The nal condence of a particular signal is a combination of the reciprocal of this residual and the mean of the complex component. A two-tap approach comparing signals on opposite sides of the geometric location of the sensor is examined and found to produce better classication. It is found that using only a single pursuit does a comparable job, reducing complexity and allowing for real-time implementation in automated target recognition systems. JOMP is particularly highlighted in comparison with a previous EMI detection algorithm known as String Match.

  2. Independent histogram pursuit for segmentation of skin lesions

    DEFF Research Database (Denmark)

    Gomez, D.D.; Butakoff, C.; Ersbøll, Bjarne Kjær

    2008-01-01

    In this paper, an unsupervised algorithm, called the Independent Histogram Pursuit (HIP), for segmenting dermatological lesions is proposed. The algorithm estimates a set of linear combinations of image bands that enhance different structures embedded in the image. In particular, the first estima...... to deal with different types of dermatological lesions. The boundary detection precision using k-means segmentation was close to 97%. The proposed algorithm can be easily combined with the majority of classification algorithms....

  3. RHIC AND THE PURSUIT OF THE QUARK-GLUON PLASMA.

    Energy Technology Data Exchange (ETDEWEB)

    MITCHELL,J.T.

    2001-07-25

    There is a fugitive on the loose. Its name is Quark-Gluon Plasma, alias the QGP. The QGP is a known informant with knowledge about the fundamental building blocks of nature that we wish to extract. This briefing will outline the status of the pursuit of the elusive QGP. We will cover what makes the QGP tick, its modus operandi, details on how we plan to hunt the fugitive down, and our level of success thus far.

  4. RHIC and the pursuit of the quark-gluon plasma

    International Nuclear Information System (INIS)

    Mitchell, J.T.

    2001-01-01

    There is a fugitive on the loose. Its name is Quark-Gluon Plasma, alias the QGP. The QGP is a known informant with knowledge about the fundamental building blocks of nature that we wish to extract. This briefing will outline the status of the pursuit of the elusive QGP. We will cover what makes the QGP tick, its modus operandi, details on how we plan to hunt the fugitive down, and our level of success thus far

  5. The Change in Smooth Pursuit Eye Movements in L-dopa- naive Parkinsonian Patients Following Administration of Subcutaneous Apomorphine

    Czech Academy of Sciences Publication Activity Database

    Bareš, M.; Brázdil, M.; Jurák, Pavel; Kaňovský, P.; Daniel, P.

    1998-01-01

    Roč. 13, 2-Suppl. (1998), s. 181 ISSN 0885-3185. [Parkinson's Disease and Movement Disorders /5./. 10.10.1998-14.10.1998, New York] Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

  6. Mixed Emotions Within the Context of Goal Pursuit.

    Science.gov (United States)

    Mejía, Shannon T; Hooker, Karen

    2017-06-01

    Development in adulthood occurs through the process of setting and working toward goals. Emotions link experiences to goals and action, and as such are integral to goal setting, evaluation of goal progress, and goal pursuit. When viewed in the context of goals, the simultaneous experience of positive and negative or "mixed" emotions coheres with the complexity of goal pursuit within the context of competing demands in daily life. Mixed emotions may be experienced as uncertainty in which goal to prioritize, ambiguity in whether an event served or impeded goal progress, or poignancy in a bittersweet moment of recognizing the losses that accompany gains. Mixed emotions therefore represent a problem that must be resolved-through either prioritization of conflicting goals, down-playing negative affective response, or goal disengagement-before goal pursuit can continue. Because mixed emotions must be resolved before they can be translated to action, the experience of mixed emotions may evoke a new awareness of priorities and available options that leads to better goal outcomes. Over time, openness to mixed emotions could result in outcomes such as better health and self-actualization.

  7. Constants, context, and change: the pursuit of purpose*

    Science.gov (United States)

    Lemkau, Henry L.

    2008-01-01

    Purpose: This lecture addresses the history and philosophy of librarianship, in general, and medical librarianship, in particular. The author discusses the profession and attempts to set its place in the context of the social and cultural worlds in which we function and in the context of the professions which we serve. Discussion: Goals are identified that are common and immutable. Examined are the changing methods by which we meet these ends, particularly the impact of technology and other factors on how we function now and in the future. Change itself is identified as the one constant of which we can be certain. That we strive and achieve is because of a sense of purpose that has guided so many of our profession's leaders. Acknowledging an embarrassment of riches, I point to the achievements of some of the most notable of my colleagues and friends, as examples of what such an extraordinary dedication to the pursuit of purpose makes possible. Conclusions: So long as we maintain this pursuit of purpose, which is, as Estelle Brodman said of the pursuit of excellence, a statement of faith in ourselves, our future is secure. PMID:18219376

  8. Constants, context, and change: the pursuit of purpose.

    Science.gov (United States)

    Lemkau, Henry L

    2008-01-01

    This lecture addresses the history and philosophy of librarianship, in general, and medical librarianship, in particular. The author discusses the profession and attempts to set its place in the context of the social and cultural worlds in which we function and in the context of the professions which we serve. Goals are identified that are common and immutable. Examined are the changing methods by which we meet these ends, particularly the impact of technology and other factors on how we function now and in the future. Change itself is identified as the one constant of which we can be certain. That we strive and achieve is because of a sense of purpose that has guided so many of our profession's leaders. Acknowledging an embarrassment of riches, I point to the achievements of some of the most notable of my colleagues and friends, as examples of what such an extraordinary dedication to the pursuit of purpose makes possible. So long as we maintain this pursuit of purpose, which is, as Estelle Brodman said of the pursuit of excellence, a statement of faith in ourselves, our future is secure.

  9. Hierarchical brain networks active in approach and avoidance goal pursuit

    Directory of Open Access Journals (Sweden)

    Jeffrey Martin Spielberg

    2013-06-01

    Full Text Available Effective approach/avoidance goal pursuit is critical for attaining long-term health and well-being. Research on the neural correlates of key goal pursuit processes (e.g., motivation has long been of interest, with lateralization in prefrontal cortex being a particularly fruitful target of investigation. However, this literature has often been limited by a lack of spatial specificity and has not delineated the precise aspects of approach/avoidance motivation involved. Additionally, the relationships among brain regions (i.e., network connectivity vital to goal pursuit remain largely unexplored. Specificity in location, process, and network relationship is vital for moving beyond gross characterizations of function and identifying the precise cortical mechanisms involved in motivation. The present paper integrates research using more spatially specific methodologies (e.g., functional magnetic resonance imaging with the rich psychological literature on approach/avoidance to propose an integrative network model that takes advantage of the strengths of each of these literatures.

  10. Nonlinear smoothing for random fields

    NARCIS (Netherlands)

    Aihara, ShinIchi; Bagchi, Arunabha

    1995-01-01

    Stochastic nonlinear elliptic partial differential equations with white noise disturbances are studied in the countably additive measure set up. Introducing the Onsager-Machlup function to the system model, the smoothing problem for maximizing the modified likelihood functional is solved and the

  11. The sweetness of successful goal pursuit: Approach-motivated pregoal states enhance the reward positivity during goal pursuit.

    Science.gov (United States)

    Threadgill, A Hunter; Gable, Philip A

    2017-12-21

    Traditionally, the reward positivity (RewP) is thought to index a binary performance monitoring system sensitive to approach motivation. However, recent theoretical models have argued that feedback processing extends beyond simple "good" vs. "bad" associations, such that performance monitoring incorporates the complex, multi-step sequence of behaviors often necessary to attain rewards. The present study sought to go beyond simple stimulus-response paradigms to examine how approach-motivated states occurring in multi-step goal pursuit impacts the RewP. Additionally, outcome frequency was varied to examine how the P3, a neural marker of expectancy, influences the RewP. Using a modified monetary incentive delay paradigm, participants played a reaction time game where multiple correct responses were required to attain a reward. Additionally, each trial had the potential for a reward (approach-motivated state) or no reward (neutral state). Results revealed that RewP amplitudes were larger after reward trial win feedback than after reward trial no-win feedback across multiple stages of goal pursuit. Additionally, after for controlling outcome frequency via the P3, RewP amplitudes were larger in reward trials than in neutral trials across incremental stages of goal pursuit. The RewP appears to be sensitive to feedback indicating successfully completing sub-goals during pursuit of a goal, even when no immediate reward is given. Approach motivation enhances performance monitoring when multiple steps are needed to attain a desired outcome, which may increase the likelihood of goal acquisition and attainment. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Smooth paths of conditional expectations

    OpenAIRE

    Andruchow, Esteban; Larotonda, Gabriel

    2010-01-01

    Let A be a von Neumann algebra with a finite trace $\\tau$, represented in $H=L^2(A,\\tau)$, and let $B_t\\subset A$ be sub-algebras, for $t$ in an interval $I$. Let $E_t:A\\to B_t$ be the unique $\\tau$-preserving conditional expectation. We say that the path $t\\mapsto E_t$ is smooth if for every $a\\in A$ and $v \\in H$, the map $$ I\

  13. Application of Projection Pursuit Model in Soilevaluation of Conservation Tillage

    Science.gov (United States)

    Yuan, Junjing; Li, Hongwen

    This paper established a conservation tillage evaluation model based on projection pursuit to evaluate the soil composite achievement of conservation tillage. After optimizing the project direction, the multi-dimension data of the seven evaluation indices are synthesized to one dimension, and the author could evaluate each item with the projection data easily, which avoided the jamming of weight matrix. The results of the evaluation mode in Linfen, Shouyang and Linghai are accordant with the production, which indicated that the model was available and provided a new method or thought to evaluate the composite achievement of conservation tillage.

  14. The Pursuit of Chronically Reliable Neural Interfaces: A Materials Perspective.

    Science.gov (United States)

    Guo, Liang

    2016-01-01

    Brain-computer interfaces represent one of the most astonishing technologies in our era. However, the grand challenge of chronic instability and limited throughput of the electrode-tissue interface has significantly hindered the further development and ultimate deployment of such exciting technologies. A multidisciplinary research workforce has been called upon to respond to this engineering need. In this paper, I briefly review this multidisciplinary pursuit of chronically reliable neural interfaces from a materials perspective by analyzing the problem, abstracting the engineering principles, and summarizing the corresponding engineering strategies. I further draw my future perspectives by extending the proposed engineering principles.

  15. Fixed Duration Pursuit-Evasion Differential Game with Integral Constraints

    International Nuclear Information System (INIS)

    Ibragimov G I; Kuchkarov A Sh

    2013-01-01

    We investigate a pursuit-evasion differential game of countably many pursuers and one evader. Integral constraints are imposed on control functions of the players. Duration of the game is fixed and the payoff of the game is infimum of the distances between the evader and pursuers when the game is completed. Purpose of the pursuers is to minimize the payoff and that of the evader is to maximize it. Optimal strategies of the players are constructed, and the value of the game is found. It should be noted that energy resource of any pursuer may be less than that of the evader.

  16. In Pursuit of Happiness, Bhutan Opens to Globalization and Business

    Directory of Open Access Journals (Sweden)

    Kimberly A. Freeman, Ph.D.

    2013-07-01

    Full Text Available The Kingdom of Bhutan, a small country situated on the border between China and India, has in recent years become a constitutional democratic monarchy. As part of its 2008 constitution, Bhutan committed to promote conditions that would enable the pursuit of Gross National Happiness. The countrythus initiated an effort to improve the quality of life and happiness for its citizens and has embraced globalization far more than previouslythrough attracting business, tourism, and communications. The author’s hereinaddress some of the initiatives provide the context within which these efforts have arisen.

  17. Polygonal approximation and energy of smooth knots

    OpenAIRE

    Rawdon, Eric J.; Simon, Jonathan K.

    2003-01-01

    We establish a fundamental connection between smooth and polygonal knot energies, showing that the Minimum Distance Energy for polygons inscribed in a smooth knot converges to the Moebius Energy of the smooth knot as the polygons converge to the smooth knot. However, the polygons must converge in a ``nice'' way, and the energies must be correctly regularized. We determine an explicit error bound between the energies in terms of the number of the edges of the polygon and the Ropelength of the ...

  18. Cerenkov luminescence tomography based on preconditioning orthogonal matching pursuit

    Science.gov (United States)

    Liu, Haixiao; Hu, Zhenhua; Wang, Kun; Tian, Jie; Yang, Xin

    2015-03-01

    Cerenkov luminescence imaging (CLI) is a novel optical imaging method and has been proved to be a potential substitute of the traditional radionuclide imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). This imaging method inherits the high sensitivity of nuclear medicine and low cost of optical molecular imaging. To obtain the depth information of the radioactive isotope, Cerenkov luminescence tomography (CLT) is established and the 3D distribution of the isotope is reconstructed. However, because of the strong absorption and scatter, the reconstruction of the CLT sources is always converted to an ill-posed linear system which is hard to be solved. In this work, the sparse nature of the light source was taken into account and the preconditioning orthogonal matching pursuit (POMP) method was established to effectively reduce the ill-posedness and obtain better reconstruction accuracy. To prove the accuracy and speed of this algorithm, a heterogeneous numerical phantom experiment and an in vivo mouse experiment were conducted. Both the simulation result and the mouse experiment showed that our reconstruction method can provide more accurate reconstruction result compared with the traditional Tikhonov regularization method and the ordinary orthogonal matching pursuit (OMP) method. Our reconstruction method will provide technical support for the biological application for Cerenkov luminescence.

  19. The Role of Visibility in Pursuit/Evasion Games

    Directory of Open Access Journals (Sweden)

    Athanasios Kehagias

    2014-12-01

    Full Text Available The cops-and-robber (CR game has been used in mobile robotics as a discretized model (played on a graph G of pursuit/evasion problems. The “classic” CR version is a perfect information game: the cops’ (pursuer’s location is always known to the robber (evader and vice versa. Many variants of the classic game can be defined: the robber can be invisible and also the robber can be either adversarial (tries to avoid capture or drunk (performs a random walk. Furthermore, the cops and robber can reside in either nodes or edges of G. Several of these variants are relevant as models or robotic pursuit/evasion. In this paper, we first define carefully several of the variants mentioned above and related quantities such as the cop number and the capture time. Then we introduce and study the cost of visibility (COV, a quantitative measure of the increase in difficulty (from the cops’ point of view when the robber is invisible. In addition to our theoretical results, we present algorithms which can be used to compute capture times and COV of graphs which are analytically intractable. Finally, we present the results of applying these algorithms to the numerical computation of COV.

  20. Hybrid Video Coding Based on Bidimensional Matching Pursuit

    Directory of Open Access Journals (Sweden)

    Lorenzo Granai

    2004-12-01

    Full Text Available Hybrid video coding combines together two stages: first, motion estimation and compensation predict each frame from the neighboring frames, then the prediction error is coded, reducing the correlation in the spatial domain. In this work, we focus on the latter stage, presenting a scheme that profits from some of the features introduced by the standard H.264/AVC for motion estimation and replaces the transform in the spatial domain. The prediction error is so coded using the matching pursuit algorithm which decomposes the signal over an appositely designed bidimensional, anisotropic, redundant dictionary. Comparisons are made among the proposed technique, H.264, and a DCT-based coding scheme. Moreover, we introduce fast techniques for atom selection, which exploit the spatial localization of the atoms. An adaptive coding scheme aimed at optimizing the resource allocation is also presented, together with a rate-distortion study for the matching pursuit algorithm. Results show that the proposed scheme outperforms the standard DCT, especially at very low bit rates.

  1. Income and Consumption Smoothing among US States

    DEFF Research Database (Denmark)

    Sørensen, Bent; Yosha, Oved

    We quantify the amount of cross-sectional income and consumption smoothing achieved within subgroups of states, such as regions or clubs, e.g. the club of rich states. We find that there is much income smoothing between as well as within regions. By contrast, consumption smoothing occurs mainly...... states. The fraction of a shock to gross state products smoothed by the federal tax-transfer system is the same for various regions and other clubs of states. We calculate the scope for consumption smoothing within various regions and clubs, finding that most gains from risk sharing can be achieved...... within US regions. Since a considerable fraction of shocks to gross state product are smoothed within regions, we conclude that existing markets achieve a substantial fraction of the potential welfare gains from interstate income and consumption smoothing. Nonetheless, non-negligible welfare gains may...

  2. Electron histochemical and autoradiographic studies of vascular smooth muscle cell

    International Nuclear Information System (INIS)

    Kameyama, Kohji; Aida, Takeo; Asano, Goro

    1982-01-01

    The authors have studied the vascular smooth muscle cell in the aorta and the arteries of brain, heart in autopsied cases, cholesterol fed rabbits and canine through electron histochemical and autoradiographic methods, using 3 H-proline and 3 H-thymidine. The vascular changes are variable presumably due to the functional and morphological difference of vessels. Aging, pathological condition and physiological requirement induce the disturbances of vascular functions as contractility. According to various pathological conditions, the smooth muscle cell altered their shape, surface properties and arrangement of subcellular organelles including changes in number. The morphological features of arteries during aging is characterized by the thickening of endothelium and media. Decreasing cellularity and increasing collagen contents in media. The autoradiographic and histochemical observations using periodic acid methenamine silver (PAM) and ruthenium red stains demonstrated that the smooth muscle cell is a connective tissue synthetic cell. The PAM impregnation have proved that the small bundle of microfilaments become associated with small conglomerate of collagen and elastic fibers. Cytochemical examination will provide sufficient evidence to establish the contribution of subcellular structure. The acid phosphatase play an important role in vascular disease and they are directly involved in cellular lipid metabolism in cholesterol fed animals, and the activity of Na-K ATPase on the plasma membrane may contribute to the regulation of vascular blood flow and vasospasms. Direct injury and subsequent abnormal contraction of smooth muscle cell may initiate increased permeability of plasma protein and lipid in the media layer and eventually may developed and enhance arteriosclerosis. (author)

  3. Metaphorical Mirror: Reflecting on Our Personal Pursuits to Discover and Challenge Our Teaching Practice Assumptions

    Science.gov (United States)

    Wagenheim, Gary; Clark, Robert; Crispo, Alexander W.

    2009-01-01

    The goal of this paper is to examine how our personal pursuits--hobbies, activities, interests, and sports--can serve as a metaphor to reflect who we are in our teaching practice. This paper explores the notion that our favorite personal pursuits serve as metaphorical mirrors to reveal deeper assumptions we hold about the skills, values, and…

  4. Smooth muscle physiology and effect of bladder and urethra muscle length/tension on response to stimulation. Part I. Review.

    Science.gov (United States)

    Bissada, N K; Finkbeiner, A E

    1980-09-01

    With particular reference to the lower urinary tract, a review of basic anatomy and physiology of smooth muscle is presented. The relationship as altered by electrica and pharmacologic stimulation is discussed.

  5. Sparse reconstruction using distribution agnostic bayesian matching pursuit

    KAUST Repository

    Masood, Mudassir

    2013-11-01

    A fast matching pursuit method using a Bayesian approach is introduced for sparse signal recovery. This method performs Bayesian estimates of sparse signals even when the signal prior is non-Gaussian or unknown. It is agnostic on signal statistics and utilizes a priori statistics of additive noise and the sparsity rate of the signal, which are shown to be easily estimated from data if not available. The method utilizes a greedy approach and order-recursive updates of its metrics to find the most dominant sparse supports to determine the approximate minimum mean-square error (MMSE) estimate of the sparse signal. Simulation results demonstrate the power and robustness of our proposed estimator. © 2013 IEEE.

  6. Compressed Sensing Image Processing Based on Stagewise Orthogonal Matching Pursuit

    Directory of Open Access Journals (Sweden)

    Kuangfeng Ning

    2014-10-01

    Full Text Available This paper studies the compressed sensing image processing based on Stagewise Orthogonal Matching Pursuit, the relative error, matching degree, and the running time of StOMP algorithm have been researched from the perspective of two-dimensional compressible signals. A simulation platform is built for StOMP algorithm simulation. Further, the performance and complexity are compared for several typical greedy algorithms such as SP, OMP, CosaMP, and StOMP. StOMP is significantly better than SP, OMP and CosaMP algorithm. Image sparsity K must be known by OMP, SP, and CosaMP algorithm, and the original signal can be gradually approached by StOMP, and its step K is unknown. StOMP algorithm can take into account the reconstruction time and reconstruction quality.

  7. Support agnostic Bayesian matching pursuit for block sparse signals

    KAUST Repository

    Masood, Mudassir

    2013-05-01

    A fast matching pursuit method using a Bayesian approach is introduced for block-sparse signal recovery. This method performs Bayesian estimates of block-sparse signals even when the distribution of active blocks is non-Gaussian or unknown. It is agnostic to the distribution of active blocks in the signal and utilizes a priori statistics of additive noise and the sparsity rate of the signal, which are shown to be easily estimated from data and no user intervention is required. The method requires a priori knowledge of block partition and utilizes a greedy approach and order-recursive updates of its metrics to find the most dominant sparse supports to determine the approximate minimum mean square error (MMSE) estimate of the block-sparse signal. Simulation results demonstrate the power and robustness of our proposed estimator. © 2013 IEEE.

  8. Radial smoothing and closed orbit

    International Nuclear Information System (INIS)

    Burnod, L.; Cornacchia, M.; Wilson, E.

    1983-11-01

    A complete simulation leading to a description of one of the error curves must involve four phases: (1) random drawing of the six set-up points within a normal population having a standard deviation of 1.3 mm; (b) random drawing of the six vertices of the curve in the sextant mode within a normal population having a standard deviation of 1.2 mm. These vertices are to be set with respect to the axis of the error lunes, while this axis has as its origins the positions defined by the preceding drawing; (c) mathematical definition of six parabolic curves and their junctions. These latter may be curves with very slight curvatures, or segments of a straight line passing through the set-up point and having lengths no longer than one LSS. Thus one gets a mean curve for the absolute errors; (d) plotting of the actually observed radial positions with respect to the mean curve (results of smoothing)

  9. Evolution on a smooth landscape

    Science.gov (United States)

    Kessler, David A.; Levine, Herbert; Ridgway, Douglas; Tsimring, Lev

    1997-05-01

    We study in detail a recently proposed simple discrete model for evolution on smooth landscapes. An asymptotic solution of this model for long times is constructed. We find that the dynamics of the population is governed by correlation functions that although being formally down by powers of N (the population size), nonetheless control the evolution process after a very short transient. The long-time behavior can be found analytically since only one of these higher order correlators (the two-point function) is relevant. We compare and contrast the exact findings derived herein with a previously proposed phenomenological treatment employing mean-field theory supplemented with a cutoff at small population density. Finally, we relate our results to the recently studied case of mutation on a totally flat landscape.

  10. Mechanics of Vascular Smooth Muscle.

    Science.gov (United States)

    Ratz, Paul H

    2015-12-15

    Vascular smooth muscle (VSM; see Table 1 for a list of abbreviations) is a heterogeneous biomaterial comprised of cells and extracellular matrix. By surrounding tubes of endothelial cells, VSM forms a regulated network, the vasculature, through which oxygenated blood supplies specialized organs, permitting the development of large multicellular organisms. VSM cells, the engine of the vasculature, house a set of regulated nanomotors that permit rapid stress-development, sustained stress-maintenance and vessel constriction. Viscoelastic materials within, surrounding and attached to VSM cells, comprised largely of polymeric proteins with complex mechanical characteristics, assist the engine with countering loads imposed by the heart pump, and with control of relengthening after constriction. The complexity of this smart material can be reduced by classical mechanical studies combined with circuit modeling using spring and dashpot elements. Evaluation of the mechanical characteristics of VSM requires a more complete understanding of the mechanics and regulation of its biochemical parts, and ultimately, an understanding of how these parts work together to form the machinery of the vascular tree. Current molecular studies provide detailed mechanical data about single polymeric molecules, revealing viscoelasticity and plasticity at the protein domain level, the unique biological slip-catch bond, and a regulated two-step actomyosin power stroke. At the tissue level, new insight into acutely dynamic stress-strain behavior reveals smooth muscle to exhibit adaptive plasticity. At its core, physiology aims to describe the complex interactions of molecular systems, clarifying structure-function relationships and regulation of biological machines. The intent of this review is to provide a comprehensive presentation of one biomachine, VSM. Copyright © 2015 John Wiley & Sons, Inc.

  11. Very smooth points of spaces of operators

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Our notation and terminology is standard and can be found in [HWW]. For a Banach space X by ∂eX1 we denote the set of extreme points. 2. Very smooth points. Let M ⊂ X be a closed subspace. It was observed in [MR] that if x ∈ M is a smooth point of X then it is a smooth point of M. It is easy to see that if every continuous.

  12. Smooth GERBS, orthogonal systems and energy minimization

    Energy Technology Data Exchange (ETDEWEB)

    Dechevsky, Lubomir T., E-mail: ltd@hin.no, E-mail: pza@hin.no; Zanaty, Peter, E-mail: ltd@hin.no, E-mail: pza@hin.no [Faculty of Technology, Narvik University College, 2 Lodve Lange' s St., P.O.Box 385, Narvik N-8505 (Norway)

    2013-12-18

    New results are obtained in three mutually related directions of the rapidly developing theory of generalized expo-rational B-splines (GERBS) [7, 6]: closed-form computability of C{sup ∞}-smooth GERBS in terms of elementary and special functions, Hermite interpolation and least-squares best approximation via smooth GERBS, energy minimizing properties of smooth GERBS similar to those of the classical cubic polynomial B-splines.

  13. Smoothed analysis of complex conic condition numbers

    OpenAIRE

    Buergisser, Peter; Cucker, Felipe; Lotz, Martin

    2006-01-01

    Smoothed analysis of complexity bounds and condition numbers has been done, so far, on a case by case basis. In this paper we consider a reasonably large class of condition numbers for problems over the complex numbers and we obtain smoothed analysis estimates for elements in this class depending only on geometric invariants of the corresponding sets of ill-posed inputs. These estimates are for a version of smoothed analysis proposed in this paper which, to the best of our knowledge, appears ...

  14. Income and Consumption Smoothing among US States

    DEFF Research Database (Denmark)

    Sørensen, Bent; Yosha, Oved

    within regions but not between regions. This suggests that capital markets transcend regional barriers while credit markets are regional in their nature. Smoothing within the club of rich states is accomplished mainly via capital markets whereas consumption smoothing is dominant within the club of poor...... states. The fraction of a shock to gross state products smoothed by the federal tax-transfer system is the same for various regions and other clubs of states. We calculate the scope for consumption smoothing within various regions and clubs, finding that most gains from risk sharing can be achieved...

  15. Energy metabolism and transduction in smooth muscle.

    Science.gov (United States)

    Lynch, R M; Paul, R J

    1985-08-15

    Early investigations into the nature of the coupling between energy transduction and metabolism in smooth muscle, particularly from the laboratories of Bülbring and Lundholm, suggested that specific metabolic pathways could independently supply energy for ion transport and actin-myosin interactions. Subsequent work has solidified the concept that oxidative phosphorylation is specifically coupled to tension generation and maintenance, whereas, aerobic glycolysis is not only a vital characteristic of smooth muscle metabolism, but also is likely to be independently coupled to Na-K transport at the plasmalemma. The independence of oxidative and glycolytic metabolism is reflected as a compartmentation of carbohydrate metabolism in the porcine carotid artery. The coupling of these independent metabolic pathways with specific energy utilizing processes, indicates a means by which energy production and transduction can be closely and efficiently regulated. The coupling of glycogenolysis to mitochondrial respiration may have evolved as a direct response to the energetic needs of VSM. That is, the large glycogenolytic response in the initial minutes of stimulation may be necessary to maximize the cellular production of ATP during the presteady state. Likewise, the coupling between aerobic glycolysis and Na-K transport indicates a sensitive and efficient means of coordinating energy metabolism with ion transport at the membrane level. Additionally, the regulation of substrate supply, i.e. glucose transport, also may be closely coordinated with changes in ion transport. One may speculate that alterations in the microenvironment of each compartment can independently regulate intermediary metabolism and therefore allow the cell to quickly and efficiently respond to localized stimuli. Thus, stimulation of Na-K transport could effectively regulate energy production at the membrane level without mobilizing or competing with the energy transduction of other cellular processes. This

  16. Local Transfer Coefficient, Smooth Channel

    Directory of Open Access Journals (Sweden)

    R. T. Kukreja

    1998-01-01

    Full Text Available Naphthalene sublimation technique and the heat/mass transfer analogy are used to determine the detailed local heat/mass transfer distributions on the leading and trailing walls of a twopass square channel with smooth walls that rotates about a perpendicular axis. Since the variation of density is small in the flow through the channel, buoyancy effect is negligible. Results show that, in both the stationary and rotating channel cases, very large spanwise variations of the mass transfer exist in he turn and in the region immediately downstream of the turn in the second straight pass. In the first straight pass, the rotation-induced Coriolis forces reduce the mass transfer on the leading wall and increase the mass transfer on the trailing wall. In the turn, rotation significantly increases the mass transfer on the leading wall, especially in the upstream half of the turn. Rotation also increases the mass transfer on the trailing wall, more in the downstream half of the turn than in the upstream half of the turn. Immediately downstream of the turn, rotation causes the mass transfer to be much higher on the trailing wall near the downstream corner of the tip of the inner wall than on the opposite leading wall. The mass transfer in the second pass is higher on the leading wall than on the trailing wall. A slower flow causes higher mass transfer enhancement in the turn on both the leading and trailing walls.

  17. Excitation of Mytilus smooth muscle.

    Science.gov (United States)

    Twarog, B M

    1967-10-01

    1. Membrane potentials and tension were recorded during nerve stimulation and direct stimulation of smooth muscle cells of the anterior byssus retractor muscle of Mytilus edulis L.2. The resting potential averaged 65 mV (range 55-72 mV).3. Junction potentials reached 25 mV and decayed to one half maximum amplitude in 500 msec. Spatial summation and facilitation of junction potentials were observed.4. Action potentials, 50 msec in duration and up to 50 mV in amplitude were fired at a membrane potential of 35-40 mV. No overshoot was observed.5. Contraction in response to neural stimulation was associated with spike discharge. Measurement of tension and depolarization in muscle bundles at high K(+) indicated that tension is only produced at membrane potentials similar to those achieved by spike discharge.6. Blocking of junction potentials, spike discharge and contraction by methantheline, an acetylcholine antagonist, supports the hypothesis that the muscle is excited by cholinergic nerves. However, evidence of a presynaptic action of methantheline complicates this argument.

  18. Smooth horizons and quantum ripples

    International Nuclear Information System (INIS)

    Golovnev, Alexey

    2015-01-01

    Black holes are unique objects which allow for meaningful theoretical studies of strong gravity and even quantum gravity effects. An infalling and a distant observer would have very different views on the structure of the world. However, a careful analysis has shown that it entails no genuine contradictions for physics, and the paradigm of observer complementarity has been coined. Recently this picture was put into doubt. In particular, it was argued that in old black holes a firewall must form in order to protect the basic principles of quantum mechanics. This AMPS paradox has already been discussed in a vast number of papers with different attitudes and conclusions. Here we want to argue that a possible source of confusion is the neglect of quantum gravity effects. Contrary to widespread perception, it does not necessarily mean that effective field theory is inapplicable in rather smooth neighbourhoods of large black hole horizons. The real offender might be an attempt to consistently use it over the huge distances from the near-horizon zone of old black holes to the early radiation. We give simple estimates to support this viewpoint and show how the Page time and (somewhat more speculative) scrambling time do appear. (orig.)

  19. Experimental evaluation of user performance in a pursuit tracking task with multimodal feedback

    Directory of Open Access Journals (Sweden)

    Obrenović Željko

    2004-01-01

    Full Text Available In this paper we describe the results of experimental evaluation of user performance in a pursuit-tracking task with multimodal feedback. Our experimental results indicate that audio can significantly improve the accuracy of pursuit tracking. Experiments with 19 participants have shown that addition of acoustic modalities reduces the error during pursuit tracking for up to 19%. Moreover, experiments indicated the existence of perceptual boundaries of multimodal HCI for different scene complexity and target speeds. We have also shown that the most appealing paradigms are not the most effective ones, which necessitates a careful quantitative analysis of proposed multimodal HCI paradigms.

  20. Very smooth points of spaces of operators

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 113; Issue 1 ... We show that when the space of compact operators is an -ideal in the space of bounded operators, a very smooth operator attains its norm at a unique vector (up to a constant multiple) and ( ) is a very smooth point of the range space.

  1. Adams operations in smooth K-theory

    OpenAIRE

    Bunke, Ulrich

    2009-01-01

    We show that the Adams operations in complex K-theory lift to operations in smooth K-theory. The main result is a Riemann-Roch type theorem about the compatibility of the Adams operations and the integration in smooth K-theory.

  2. Smoothed Analysis of Local Search Algorithms

    NARCIS (Netherlands)

    Manthey, Bodo; Dehne, Frank; Sack, Jörg-Rüdiger; Stege, Ulrike

    2015-01-01

    Smoothed analysis is a method for analyzing the performance of algorithms for which classical worst-case analysis fails to explain the performance observed in practice. Smoothed analysis has been applied to explain the performance of a variety of algorithms in the last years. One particular class of

  3. Smoothing a Piecewise-Smooth: An Example from Plankton Population Dynamics

    DEFF Research Database (Denmark)

    Piltz, Sofia Helena

    2016-01-01

    In this work we discuss a piecewise-smooth dynamical system inspired by plankton observations and constructed for one predator switching its diet between two different types of prey. We then discuss two smooth formulations of the piecewise-smooth model obtained by using a hyperbolic tangent funct...

  4. Ca2+ sparks act as potent regulators of excitation-contraction coupling in airway smooth muscle.

    Science.gov (United States)

    Zhuge, Ronghua; Bao, Rongfeng; Fogarty, Kevin E; Lifshitz, Lawrence M

    2010-01-15

    Ca2+ sparks are short lived and localized Ca2+ transients resulting from the opening of ryanodine receptors in sarcoplasmic reticulum. These events relax certain types of smooth muscle by activating big conductance Ca2+-activated K+ channels to produce spontaneous transient outward currents (STOCs) and the resultant closure of voltage-dependent Ca2+ channels. But in many smooth muscles from a variety of organs, Ca2+ sparks can additionally activate Ca2+-activated Cl(-) channels to generate spontaneous transient inward current (STICs). To date, the physiological roles of Ca2+ sparks in this latter group of smooth muscle remain elusive. Here, we show that in airway smooth muscle, Ca2+ sparks under physiological conditions, activating STOCs and STICs, induce biphasic membrane potential transients (BiMPTs), leading to membrane potential oscillations. Paradoxically, BiMPTs stabilize the membrane potential by clamping it within a negative range and prevent the generation of action potentials. Moreover, blocking either Ca2+ sparks or hyperpolarization components of BiMPTs activates voltage-dependent Ca2+ channels, resulting in an increase in global [Ca2+](i) and cell contraction. Therefore, Ca2+ sparks in smooth muscle presenting both STICs and STOCs act as a stabilizer of membrane potential, and altering the balance can profoundly alter the status of excitability and contractility. These results reveal a novel mechanism underlying the control of excitability and contractility in smooth muscle.

  5. Action and pursuit of the summit of the earth

    International Nuclear Information System (INIS)

    Saavedra, Sandra; Guerrero, Juan Carlos

    1996-01-01

    The effect to guarantee the execution and of the commitments and activities to materialize the agreements and the program 21 emanated of the summit of the earth, the international community gathered in Rio called in that program to conform a Commission of Sustainable Development (CSD) through the United Nations (UN) In its session number forty seven of 1992, the general assembly of the UN defined, by means of the resolution 471 191, the composition of the CSD, the bases for the participation of the non government organizations (ONG) in her and its relationship with other organisms of the UN. Today the commission has an own secretary and it is attributed to the Economic and Social Council (ECOSOC) The CSD should carry out an effective pursuit on the world execution of all the commitments acquired in the conference of Rio, evaluating, mainly, the progressive application of the program 21 to national, regional and international scale. It also promotes the development of the international cooperation and it contributes to rationalize the process of taking of intergovernmental decisions as regards sustainable development

  6. Procrustes rotation as a diagnostic tool for projection pursuit analysis.

    Science.gov (United States)

    Wentzell, Peter D; Hou, Siyuan; Silva, Carolina Santos; Wicks, Chelsi C; Pimentel, Maria Fernanda

    2015-06-02

    Projection pursuit (PP) is an effective exploratory data analysis tool because it optimizes the projection of high dimensional data using distributional characteristics rather than variance or distance metrics. The recent development of fast and simple PP algorithms based on minimization of kurtosis for clustering data has made this powerful tool more accessible, but under conditions where the sample-to-variable ratio is small, PP fails due to opportunistic overfitting of random correlations to limiting distributional targets. Therefore, some kind of variable compression or data regularization is required in these cases. However, this introduces an additional parameter whose optimization is manually time consuming and subject to bias. The present work describes the use of Procrustes analysis as diagnostic tool that can be used to evaluate the results of PP analysis in an efficient manner. Through Procrustes rotation, the similarity of different PP projections can be examined in an automated fashion with "Procrustes maps" to establish regions of stable projections as a function of the parameter to be optimized. The application of this diagnostic is demonstrated using principal components analysis to compress FTIR spectra from ink samples of ten different brands of pen, and also in conjunction with regularized PP for soybean disease classification. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Reinforced Intrusion Detection Using Pursuit Reinforcement Competitive Learning

    Directory of Open Access Journals (Sweden)

    Indah Yulia Prafitaning Tiyas

    2014-06-01

    Full Text Available Today, information technology is growing rapidly,all information can be obtainedmuch easier. It raises some new problems; one of them is unauthorized access to the system. We need a reliable network security system that is resistant to a variety of attacks against the system. Therefore, Intrusion Detection System (IDS required to overcome the problems of intrusions. Many researches have been done on intrusion detection using classification methods. Classification methodshave high precision, but it takes efforts to determine an appropriate classification model to the classification problem. In this paper, we propose a new reinforced approach to detect intrusion with On-line Clustering using Reinforcement Learning. Reinforcement Learning is a new paradigm in machine learning which involves interaction with the environment.It works with reward and punishment mechanism to achieve solution. We apply the Reinforcement Learning to the intrusion detection problem with considering competitive learning using Pursuit Reinforcement Competitive Learning (PRCL. Based on the experimental result, PRCL can detect intrusions in real time with high accuracy (99.816% for DoS, 95.015% for Probe, 94.731% for R2L and 99.373% for U2R and high speed (44 ms.The proposed approach can help network administrators to detect intrusion, so the computer network security systembecome reliable. Keywords: Intrusion Detection System, On-Line Clustering, Reinforcement Learning, Unsupervised Learning.

  8. Implicit sequence learning in a continuous pursuit-tracking task.

    Science.gov (United States)

    Lang, Alexandre; Gapenne, Olivier; Aubert, Dominique; Ferrel-Chapus, Carole

    2013-09-01

    Assessing implicit learning in the continuous pursuit-tracking task usually concerns a repeated segment of target displacements masked by two random segments, as referred to as Pew's paradigm. Evidence for segment learning in this paradigm is scanty and contrasts with robust sequence learning in discrete tracking tasks. The present study investigates this issue with two experiments in which participants (N = 56) performed a continuous tracking task. Contrary to Pew's paradigm, participants were presented with a training sequence that was continuously cycled during 14 blocks of practice, but Block 12 in which a transfer sequence was introduced. Results demonstrate sequence learning in several conditions except in the condition that was obviously the most similar to previous studies failing to induce segment learning. Specifically, it is shown here that a target moving too slowly combined with variable time at which target reversal occurs prevents sequence learning. In addition, data from a post-experimental recognition test indicate that sequence learning was associated with explicit perceptual knowledge about the repetitive structure. We propose that learning repetition in a continuous tracking task is conditional on its capacity to (1) allow participants to detect the repeated regularities and (2) restrict feedback-based tracking strategies.

  9. Research on Multirobot Pursuit Task Allocation Algorithm Based on Emotional Cooperation Factor

    Directory of Open Access Journals (Sweden)

    Baofu Fang

    2014-01-01

    Full Text Available Multirobot task allocation is a hot issue in the field of robot research. A new emotional model is used with the self-interested robot, which gives a new way to measure self-interested robots’ individual cooperative willingness in the problem of multirobot task allocation. Emotional cooperation factor is introduced into self-interested robot; it is updated based on emotional attenuation and external stimuli. Then a multirobot pursuit task allocation algorithm is proposed, which is based on emotional cooperation factor. Combined with the two-step auction algorithm recruiting team leaders and team collaborators, set up pursuit teams, and finally use certain strategies to complete the pursuit task. In order to verify the effectiveness of this algorithm, some comparing experiments have been done with the instantaneous greedy optimal auction algorithm; the results of experiments show that the total pursuit time and total team revenue can be optimized by using this algorithm.

  10. Differential games a mathematical theory with applications to warfare and pursuit, control and optimization

    CERN Document Server

    Isaacs, Rufus

    1999-01-01

    Definitive work draws on game theory, calculus of variations, and control theory to solve an array of problems: military, pursuit and evasion, athletic contests, many more. Detailed examples, formal calculations. 1965 edition.

  11. A Model of the Effects of Acceleration on a Pursuit Tracking Task

    National Research Council Canada - National Science Library

    McKinley, Richard A; Fullerton, Kathy L; Tripp, Jr., Lloyd D; Esken, Robert L; Goodyear, Chuck

    2004-01-01

    .... A mathematical model of this task could become useful when planning air combat missions. Eight subjects performed a 2-D manual pursuit tracking task during four different Gz conditions in a human centrifuge simulator...

  12. Toward Simulating Realistic Pursuit-Evasion Using a Roadmap-Based Approach

    KAUST Repository

    Rodriguez, Samuel

    2010-01-01

    In this work, we describe an approach for modeling and simulating group behaviors for pursuit-evasion that uses a graph-based representation of the environment and integrates multi-agent simulation with roadmap-based path planning. We demonstrate the utility of this approach for a variety of scenarios including pursuit-evasion on terrains, in multi-level buildings, and in crowds. © 2010 Springer-Verlag Berlin Heidelberg.

  13. Racing cyclist power requirements in the 4000-m individual and team pursuits.

    Science.gov (United States)

    Broker, J P; Kyle, C R; Burke, E R

    1999-11-01

    The purpose of this paper is: 1) to present field test data describing the power requirements of internationally competitive individual and team pursuiters, and 2) to develop a theoretical model for pursuit power based upon on these tests. In preparing U.S. cycling's pursuit team for the 1996 Atlanta Olympics, U.S. team scientists measured cycling power of seven subjects on the Atlanta track using a crank dynamometer (SRM) at speeds from 57 to 60 kph. By using these field data and other tests, mathematical models were devised which predict both individual and team pursuit performance. The field data indicate the power within a pace line at 60 kph averages 607 W in lead position (100%), 430 W in second position (70.8%), 389 W in third position (64.1%), and 389 W in fourth position (64.0%). A team member requires about 75% of the energy necessary for cyclists riding alone at the same speed. These results compare well with field measurements from a British pursuit team, to recent wind tunnel tests, and to earlier bicycle coast down tests. The theoretical models predict performance with reasonable accuracy when the average power potential of an individual or team is known, or they may be used to estimate the power of pursuit competitors knowing race times. The model estimates that Christopher Boardman averaged about 520 W when setting his 1996, 4000-m individual pursuit record of 4 min 11.114 s and the Italian 4000-m pursuit team averaged about 480 W in setting their record of 4:00.958. Both used the "Superman" cycling position. These records would be very difficult to break using less aerodynamic riding positions, due to the extraordinarily high power requirements.

  14. Smooth halos in the cosmic web

    International Nuclear Information System (INIS)

    Gaite, José

    2015-01-01

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

  15. An artificial bee colony optimization based matching pursuit approach for ultrasonic echo estimation.

    Science.gov (United States)

    Qi, Ai-Ling; Zhang, Guang-Ming; Dong, Ming; Ma, Hong-Wei; Harvey, David M

    2018-03-07

    Ultrasonic echo estimation is important in ultrasonic non-destructive evaluation and material characterization. Matching pursuit is one of the most popular methods for the purpose of estimating ultrasonic echoes. In this paper, an artificial bee colony optimization based matching pursuit approach (ABC-MP) is proposed specifically for ultrasonic signal decomposition by integrating the artificial bee colony algorithm into the matching pursuit method. The optimal atoms are searched from a continuous parameter space over a tailored Gabor dictionary in ABC-MP instead of a discrete parameter space in matching pursuit. As a result, echoes characterized by a set of physical parameters can be estimated accurately and efficiently. The performance of ABC-MP is tested using both simulated signals and real ultrasonic signals, and compared with matching pursuit. Results clearly demonstrate the superior performance of the proposed ABC-MP approach over matching pursuit in ultrasonic echo estimation in terms of the shape and amplitude of the recovered echoes and the reconstructed signal, and the residue signal. Copyright © 2018. Published by Elsevier B.V.

  16. Bifurcations of non-smooth systems

    Science.gov (United States)

    Angulo, Fabiola; Olivar, Gerard; Osorio, Gustavo A.; Escobar, Carlos M.; Ferreira, Jocirei D.; Redondo, Johan M.

    2012-12-01

    Non-smooth systems (namely piecewise-smooth systems) have received much attention in the last decade. Many contributions in this area show that theory and applications (to electronic circuits, mechanical systems, …) are relevant to problems in science and engineering. Specially, new bifurcations have been reported in the literature, and this was the topic of this minisymposium. Thus both bifurcation theory and its applications were included. Several contributions from different fields show that non-smooth bifurcations are a hot topic in research. Thus in this paper the reader can find contributions from electronics, energy markets and population dynamics. Also, a carefully-written specific algebraic software tool is presented.

  17. Effect of pharmacologically induced smooth muscle activation on permeability in murine colitis

    NARCIS (Netherlands)

    F.J. Zijlstra (Freek); M.E. van Meeteren (Marieke); I.M. Garrelds (Ingrid); M.A.C. Meijssen (Maarten)

    2003-01-01

    textabstractBACKGROUND: Both intestinal permeability and contractility are altered in inflammatory bowel disease. Little is known about their mutual relation. Therefore, an in vitro organ bath technique was developed to investigate the simultaneous effects of inflammation on permeability and smooth

  18. Current economic downturn and supply chain : The significance of demand and inventory smoothing

    NARCIS (Netherlands)

    Cannella, S.; Ashayeri, J.; Miranda, P.A.; Bruccoleri, M.

    2014-01-01

    The aim of this article is to analyse and quantify the effects of demand and inventory smoothing into supply-chain performance, facing the extreme volatility and impetuous alteration of the market produced by the current economic recession. To do so, we model a traditional serial three-stage supply

  19. Extracellular matrix in airway smooth muscle is associated with dynamics of airway function in asthma

    NARCIS (Netherlands)

    Yick, C. Y.; Ferreira, D. S.; Annoni, R.; von der Thüsen, J. H.; Kunst, P. W.; Bel, E. H.; Lutter, R.; Mauad, T.; Sterk, P. J.

    2012-01-01

    Background: Altered deposition of extracellular matrix (ECM) in the airway smooth muscle (ASM) layer as observed in asthma may influence ASM mechanical properties. We hypothesized that ECM in ASM is associated with airway function in asthma. First, we investigated the difference in ECM expression in

  20. Lessons learned in the pursuit of a dream.

    Science.gov (United States)

    Reznick, Richard

    2014-08-01

    The author describes a career in which he combined clinical surgery with the formal study of medical education. In the 1980s, when the author embarked on this career track, it was an uncommon pathway. Over the last 30 years there has been an exponential increase in the number of individuals who have made medical education their principal academic focus. This paper provides examples from the author's personal story and lessons derived from that experience. The author outlines his experience of attaining formal training in education and concludes that this training was a foundational element in his pursuit of a career in health education research. The author describes his involvement in the transition from paper and pencil-based tests to performance-based testing in high-stakes examinations. He describes the development of a research centre in health professions education and the establishment of a simulation centre. The author's experiences in the development of an examination intended to measure technical skills, in the adoption of surgical safety checklists and in the elaboration of a programme in competency-based education are discussed. The author describes several of the lessons learned in the course of his career in medical education. He argues that successful enterprises in scholarship in medicine are almost invariably the product of interdisciplinarity. He describes the power of a joint venture between a university and an academic hospital. He argues that the geographical footprint of an emerging centre is critical. He discusses the importance of graduate studentship in an emerging discipline and enterprise. © 2014 John Wiley & Sons Ltd.

  1. Smooth School Transitions: Tips for Military Families

    Science.gov (United States)

    ... Life Listen Text Size Email Print Share Smooth School Transitions: Tips for Military Families Page Content Article ... Internet is a great resource for this. District & School Web sites Parents and children can visit the ...

  2. Cardiac, Skeletal, and smooth muscle mitochondrial respiration

    DEFF Research Database (Denmark)

    Park, Song-Young; Gifford, Jayson R; Andtbacka, Robert H I

    2014-01-01

    in cardiac, skeletal, and smooth muscle suggest all mitochondria are created equal, the contrasting RCR and non-phosphorylating respiration highlight the existence of intrinsic functional differences between these muscle mitochondria. This likely influences the efficiency of oxidative phosphorylation...

  3. Smooth surfaces from rational bilinear patches

    KAUST Repository

    Shi, Ling

    2014-01-01

    Smooth freeform skins from simple panels constitute a challenging topic arising in contemporary architecture. We contribute to this problem area by showing how to approximate a negatively curved surface by smoothly joined rational bilinear patches. The approximation problem is solved with help of a new computational approach to the hyperbolic nets of Huhnen-Venedey and Rörig and optimization algorithms based on it. We also discuss its limits which lie in the topology of the input surface. Finally, freeform deformations based on Darboux transformations are used to generate smooth surfaces from smoothly joined Darboux cyclide patches; in this way we eliminate the restriction to surfaces with negative Gaussian curvature. © 2013 Elsevier B.V.

  4. Some splines produced by smooth interpolation

    Czech Academy of Sciences Publication Activity Database

    Segeth, Karel

    2018-01-01

    Roč. 319, 15 February (2018), s. 387-394 ISSN 0096-3003 R&D Projects: GA ČR GA14-02067S Institutional support: RVO:67985840 Keywords : smooth data approximation * smooth data interpolation * cubic spline Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 1.738, year: 2016 http://www. science direct.com/ science /article/pii/S0096300317302746?via%3Dihub

  5. Some splines produced by smooth interpolation

    Czech Academy of Sciences Publication Activity Database

    Segeth, Karel

    2018-01-01

    Roč. 319, 15 February (2018), s. 387-394 ISSN 0096-3003 R&D Projects: GA ČR GA14-02067S Institutional support: RVO:67985840 Keywords : smooth data approximation * smooth data interpolation * cubic spline Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 1.738, year: 2016 http://www.sciencedirect.com/science/article/pii/S0096300317302746?via%3Dihub

  6. Smooth embeddings with Stein surface images

    OpenAIRE

    Gompf, Robert E.

    2011-01-01

    A simple characterization is given of open subsets of a complex surface that smoothly perturb to Stein open subsets. As applications, complex 2-space C^2 contains domains of holomorphy (Stein open subsets) that are exotic R^4's, and others homotopy equivalent to the 2-sphere but cut out by smooth, compact 3-manifolds. Pseudoconvex embeddings of Brieskorn spheres and other 3-manifolds into complex surfaces are constructed, as are pseudoconcave holomorphic fillings (with disagreeing contact and...

  7. Optimal Smooth Consumption and Annuity Design

    DEFF Research Database (Denmark)

    Bruhn, Kenneth; Steffensen, Mogens

    2013-01-01

    We propose an optimization criterion that yields extraordinary consumption smoothing compared to the well known results of the life-cycle model. Under this criterion we solve the related consumption and investment optimization problem faced by individuals with preferences for intertemporal stabil...... stability in consumption. We find that the consumption and investment patterns demanded under the optimization criterion is in general offered as annuity benefits from products in the class of ‘Formula Based Smoothed Investment-Linked Annuities’....

  8. Aging impairs Ca2+ sensitization pathways in gallbladder smooth muscle.

    Science.gov (United States)

    Macias, Beatriz; Gomez-Pinilla, Pedro J; Camello-Almaraz, Cristina; Pascua, Patricia; Tresguerres, Jesus Af; Camello, Pedro J; Pozo, Maria J

    2012-08-01

    Calcium sensitization is an important physiological process in agonist-induced contraction of smooth muscle. In brief, calcium sensitization is a pathway that leads to smooth muscle contraction independently of changes in [Ca(2+)](i) by mean of inhibition of myosin light chain phosphatase. Aging has negative impacts on gallbladder contractile response due to partial impairment in calcium signaling and alterations in the contractile machinery. However, information regarding aging-induced alterations in calcium sensitization is scanty. We hypothesized that the calcium sensitization system is negatively affected by age. To investigate this, gallbladders were collected from adult (4 months old) and aged (22-24 months old) guinea pigs. To evaluate the contribution of calcium sensitization pathways we assayed the effect of the specific inhibitors Y-27632 and GF109203X on the "in vitro" isometric gallbladder contractions induced by agonist challenges. In addition, expression and phosphorylation (as activation index) of proteins participating in the calcium sensitization pathways were quantified by Western blotting. Aging reduced bethanechol- and cholecystokinin-evoked contractions, an effect associated with a reduction in MLC20 phosphorylation and in the effects of both Y-27632 and GF109203X. In addition, there was a drop in ROCK I, ROCK II, MYPT-1 and PKC expression and in the activation/phosphorylation of MYPT-1, PKC and CPI-17 in response to agonists. Interestingly, melatonin treatment for 4 weeks restored gallbladder contractile responses due to re-establishment of calcium sensitization pathways. These results demonstrate that age-related gallbladder hypocontractility is associated to alterations of calcium sensitization pathways and that melatonin treatment exerts beneficial effects in the recovery of gallbladder contractility.

  9. Smooth Muscle Endothelin B Receptors Regulate Blood Pressure but Not Vascular Function or Neointimal Remodeling.

    Science.gov (United States)

    Miller, Eileen; Czopek, Alicja; Duthie, Karolina M; Kirkby, Nicholas S; van de Putte, Elisabeth E Fransen; Christen, Sibylle; Kimmitt, Robert A; Moorhouse, Rebecca; Castellan, Raphael F P; Kotelevtsev, Yuri V; Kuc, Rhoda E; Davenport, Anthony P; Dhaun, Neeraj; Webb, David J; Hadoke, Patrick W F

    2017-02-01

    The role of smooth muscle endothelin B (ET B ) receptors in regulating vascular function, blood pressure (BP), and neointimal remodeling has not been established. Selective knockout mice were generated to address the hypothesis that loss of smooth muscle ET B receptors would reduce BP, alter vascular contractility, and inhibit neointimal remodeling. ET B receptors were selectively deleted from smooth muscle by crossing floxed ET B mice with those expressing cre-recombinase controlled by the transgelin promoter. Functional consequences of ET B deletion were assessed using myography. BP was measured by telemetry, and neointimal lesion formation induced by femoral artery injury. Lesion size and composition (day 28) were analyzed using optical projection tomography, histology, and immunohistochemistry. Selective deletion of ET B was confirmed by genotyping, autoradiography, polymerase chain reaction, and immunohistochemistry. ET B -mediated contraction was reduced in trachea, but abolished from mesenteric veins, of knockout mice. Induction of ET B -mediated contraction in mesenteric arteries was also abolished in these mice. Femoral artery function was unaltered, and baseline BP modestly elevated in smooth muscle ET B knockout compared with controls (+4.2±0.2 mm Hg; P<0.0001), but salt-induced and ET B blockade-mediated hypertension were unaltered. Circulating endothelin-1 was not altered in knockout mice. ET B -mediated contraction was not induced in femoral arteries by incubation in culture medium or lesion formation, and lesion size was not altered in smooth muscle ET B knockout mice. In the absence of other pathology, ET B receptors in vascular smooth muscle make a small but significant contribution to ET B -dependent regulation of BP. These ET B receptors have no effect on vascular contraction or neointimal remodeling. © 2016 The Authors.

  10. A Pursuit Theory Account for the Perception of Common Motion in Motion Parallax.

    Science.gov (United States)

    Ratzlaff, Michael; Nawrot, Mark

    2016-09-01

    The visual system uses an extraretinal pursuit eye movement signal to disambiguate the perception of depth from motion parallax. Visual motion in the same direction as the pursuit is perceived nearer in depth while visual motion in the opposite direction as pursuit is perceived farther in depth. This explanation of depth sign applies to either an allocentric frame of reference centered on the fixation point or an egocentric frame of reference centered on the observer. A related problem is that of depth order when two stimuli have a common direction of motion. The first psychophysical study determined whether perception of egocentric depth order is adequately explained by a model employing an allocentric framework, especially when the motion parallax stimuli have common rather than divergent motion. A second study determined whether a reversal in perceived depth order, produced by a reduction in pursuit velocity, is also explained by this model employing this allocentric framework. The results show than an allocentric model can explain both the egocentric perception of depth order with common motion and the perceptual depth order reversal created by a reduction in pursuit velocity. We conclude that an egocentric model is not the only explanation for perceived depth order in these common motion conditions. © The Author(s) 2016.

  11. Simple Motion Pursuit and Evasion Differential Games with Many Pursuers on Manifolds with Euclidean Metric

    Directory of Open Access Journals (Sweden)

    Atamurat Kuchkarov

    2016-01-01

    Full Text Available We consider pursuit and evasion differential games of a group of m pursuers and one evader on manifolds with Euclidean metric. The motions of all players are simple, and maximal speeds of all players are equal. If the state of a pursuer coincides with that of the evader at some time, we say that pursuit is completed. We establish that each of the differential games (pursuit or evasion is equivalent to a differential game of m groups of countably many pursuers and one group of countably many evaders in Euclidean space. All the players in any of these groups are controlled by one controlled parameter. We find a condition under which pursuit can be completed, and if this condition is not satisfied, then evasion is possible. We construct strategies for the pursuers in pursuit game which ensure completion the game for a finite time and give a formula for this time. In the case of evasion game, we construct a strategy for the evader.

  12. TAX SMOOTHING: TESTS ON INDONESIAN DATA

    Directory of Open Access Journals (Sweden)

    Rudi Kurniawan

    2011-01-01

    Full Text Available This paper contributes to the literature of public debt management by testing for tax smoothing behaviour in Indonesia. Tax smoothing means that the government smooths the tax rate across all future time periods to minimize the distortionary costs of taxation over time for a given path of government spending. In a stochastic economy with an incomplete bond market, tax smoothing implies that the tax rate approximates a random walk and changes in the tax rate are nearly unpredictable. For that purpose, two tests were performed. First, random walk behaviour of the tax rate was examined by undertaking unit root tests. The null hypothesis of unit root cannot be rejected, indicating that the tax rate is nonstationary and, hence, it follows a random walk. Second, the predictability of the tax rate was examined by regressing changes in the tax rate on its own lagged values and also on lagged values of changes in the goverment expenditure ratio, and growth of real output. They are found to be not significant in predicting changes in the tax rate. Taken together, the present evidence seems to be consistent with the tax smoothing, therefore provides support to this theory.

  13. Voltage dependent potassium channel remodeling in murine intestinal smooth muscle hypertrophy induced by partial obstruction.

    Science.gov (United States)

    Liu, Dong-Hai; Huang, Xu; Guo, Xin; Meng, Xiang-Min; Wu, Yi-Song; Lu, Hong-Li; Zhang, Chun-Mei; Kim, Young-chul; Xu, Wen-Xie

    2014-01-01

    Partial obstruction of the small intestine causes obvious hypertrophy of smooth muscle cells and motility disorder in the bowel proximate to the obstruction. To identify electric remodeling of hypertrophic smooth muscles in partially obstructed murine small intestine, the patch-clamp and intracellular microelectrode recording methods were used to identify the possible electric remodeling and Western blot, immunofluorescence and immunoprecipitation were utilized to examine the channel protein expression and phosphorylation level changes in this research. After 14 days of obstruction, partial obstruction caused obvious smooth muscle hypertrophy in the proximally located intestine. The slow waves of intestinal smooth muscles in the dilated region were significantly suppressed, their amplitude and frequency were reduced, whilst the resting membrane potentials were depolarized compared with normal and sham animals. The current density of voltage dependent potassium channel (KV) was significantly decreased in the hypertrophic smooth muscle cells and the voltage sensitivity of KV activation was altered. The sensitivity of KV currents (IKV) to TEA, a nonselective potassium channel blocker, increased significantly, but the sensitivity of IKv to 4-AP, a KV blocker, stays the same. The protein levels of KV4.3 and KV2.2 were up-regulated in the hypertrophic smooth muscle cell membrane. The serine and threonine phosphorylation levels of KV4.3 and KV2.2 were significantly increased in the hypertrophic smooth muscle cells. Thus this study represents the first identification of KV channel remodeling in murine small intestinal smooth muscle hypertrophy induced by partial obstruction. The enhanced phosphorylations of KV4.3 and KV2.2 may be involved in this process.

  14. Voltage dependent potassium channel remodeling in murine intestinal smooth muscle hypertrophy induced by partial obstruction.

    Directory of Open Access Journals (Sweden)

    Dong-Hai Liu

    Full Text Available Partial obstruction of the small intestine causes obvious hypertrophy of smooth muscle cells and motility disorder in the bowel proximate to the obstruction. To identify electric remodeling of hypertrophic smooth muscles in partially obstructed murine small intestine, the patch-clamp and intracellular microelectrode recording methods were used to identify the possible electric remodeling and Western blot, immunofluorescence and immunoprecipitation were utilized to examine the channel protein expression and phosphorylation level changes in this research. After 14 days of obstruction, partial obstruction caused obvious smooth muscle hypertrophy in the proximally located intestine. The slow waves of intestinal smooth muscles in the dilated region were significantly suppressed, their amplitude and frequency were reduced, whilst the resting membrane potentials were depolarized compared with normal and sham animals. The current density of voltage dependent potassium channel (KV was significantly decreased in the hypertrophic smooth muscle cells and the voltage sensitivity of KV activation was altered. The sensitivity of KV currents (IKV to TEA, a nonselective potassium channel blocker, increased significantly, but the sensitivity of IKv to 4-AP, a KV blocker, stays the same. The protein levels of KV4.3 and KV2.2 were up-regulated in the hypertrophic smooth muscle cell membrane. The serine and threonine phosphorylation levels of KV4.3 and KV2.2 were significantly increased in the hypertrophic smooth muscle cells. Thus this study represents the first identification of KV channel remodeling in murine small intestinal smooth muscle hypertrophy induced by partial obstruction. The enhanced phosphorylations of KV4.3 and KV2.2 may be involved in this process.

  15. Smooth muscle actin and myosin expression in cultured airway smooth muscle cells.

    Science.gov (United States)

    Wong, J Z; Woodcock-Mitchell, J; Mitchell, J; Rippetoe, P; White, S; Absher, M; Baldor, L; Evans, J; McHugh, K M; Low, R B

    1998-05-01

    In this study, the expression of smooth muscle actin and myosin was examined in cultures of rat tracheal smooth muscle cells. Protein and mRNA analyses demonstrated that these cells express alpha- and gamma-smooth muscle actin and smooth muscle myosin and nonmuscle myosin-B heavy chains. The expression of the smooth muscle specific actin and myosin isoforms was regulated in the same direction when growth conditions were changed. Thus, at confluency in 1 or 10% serum-containing medium as well as for low-density cells (50-60% confluent) deprived of serum, the expression of the smooth muscle forms of actin and myosin was relatively high. Conversely, in rapidly proliferating cultures at low density in 10% serum, smooth muscle contractile protein expression was low. The expression of nonmuscle myosin-B mRNA and protein was more stable and was upregulated only to a small degree in growing cells. Our results provide new insight into the molecular basis of differentiation and contractile function in airway smooth muscle cells.

  16. Effects of slope smoothing in river channel modeling

    Science.gov (United States)

    Kim, Kyungmin; Liu, Frank; Hodges, Ben R.

    2017-04-01

    In extending dynamic river modeling with the 1D Saint-Venant equations from a single reach to a large watershed there are critical questions as to how much bathymetric knowledge is necessary and how it should be represented parsimoniously. The ideal model will include the detail necessary to provide realism, but not include extraneous detail that should not exert a control on a 1D (cross-section averaged) solution. In a Saint-Venant model, the overall complexity of the river channel morphometry is typically abstracted into metrics for the channel slope, cross-sectional area, hydraulic radius, and roughness. In stream segments where cross-section surveys are closely spaced, it is not uncommon to have sharp changes in slope or even negative values (where a positive slope is the downstream direction). However, solving river flow with the Saint-Venant equations requires a degree of smoothness in the equation parameters or the equation set with the directly measured channel slopes may not be Lipschitz continuous. The results of non-smoothness are typically extended computational time to converge solutions (or complete failure to converge) and/or numerical instabilities under transient conditions. We have investigated using cubic splines to smooth the bottom slope and ensure always positive reference slopes within a 1D model. This method has been implemented in the Simulation Program for River Networks (SPRNT) and is compared to the standard HEC-RAS river solver. It is shown that the reformulation of the reference slope is both in keeping with the underlying derivation of the Saint-Venant equations and provides practical numerical stability without altering the realism of the simulation. This research was supported in part by the National Science Foundation under grant number CCF-1331610.

  17. Local smoothness for global optical flow

    DEFF Research Database (Denmark)

    Rakêt, Lars Lau

    2012-01-01

    We consider the problem of estimating the “smoothness parameter” that controls the tradeoff between data fidelity and regularity in optical flow estimation. We start by reviewing the problem of global estimation using the Optimal Prediction Principle (OPP) by Zimmer et al. Inspired...... by this technique and work on local-global optical flow we propose a simple method for fusing optical flow estimates of different smoothness by evaluating interpolation quality locally by means of L1 block match on the corresponding set of gradient images. We illustrate the method in a setting where optical flows...... are estimated by a TV-L1 energy. On average this procedure reduces the average endpoint error by 15% over flows estimated using the OPP, and gives flow fields that are consistently better than the single best flows with a fixed smoothness parameter....

  18. Sparsity Adaptive Matching Pursuit Detection Algorithm Based on Compressed Sensing for Radar Signals.

    Science.gov (United States)

    Wei, Yanbo; Lu, Zhizhong; Yuan, Gannan; Fang, Zhao; Huang, Yu

    2017-05-13

    In this paper, the application of the emerging compressed sensing (CS) theory and the geometric characteristics of the targets in radar images are investigated. Currently, the signal detection algorithms based on the CS theory require knowing the prior knowledge of the sparsity of target signals. However, in practice, it is often impossible to know the sparsity in advance. To solve this problem, a novel sparsity adaptive matching pursuit (SAMP) detection algorithm is proposed. This algorithm executes the detection task by updating the support set and gradually increasing the sparsity to approximate the original signal. To verify the effectiveness of the proposed algorithm, the data collected in 2010 at Pingtan, which located on the coast of the East China Sea, were applied. Experiment results illustrate that the proposed method adaptively completes the detection task without knowing the signal sparsity, and the similar detection performance is close to the matching pursuit (MP) and orthogonal matching pursuit (OMP) detection algorithms.

  19. Life, liberty, and the pursuit of happiness: reframing inequities experienced by people with severe mental illness.

    Science.gov (United States)

    Whitley, Rob; Henwood, Benjamin F

    2014-03-01

    In the Declaration of Independence, Thomas Jefferson stated that citizens of the new republic had fundamental and inalienable rights to "life, liberty and the pursuit of happiness." The purpose of this article is to reframe inequities experienced by people living with severe mental illnesses in terms of violations of Jeffersonian rights to "life, liberty and the pursuit of happiness." We simultaneously consider governmental and clinical efforts to address identified inequities and uphold these rights. The broad research literature on severe mental illnesses was examined. People with severe mental illnesses experience numerous inequities regarding "life, liberty and the pursuit of happiness." These inequities include diminished life expectancy, excessive involuntary commitment and elevated rates of unemployment and homelessness. Governmental and clinical responses to such inequities include the Affordable Care Act and the Olmstead Decision, as well as recovery-oriented interventions such as Supported Employment and Supported Housing.

  20. Correntropy Matching Pursuit With Application to Robust Digit and Face Recognition.

    Science.gov (United States)

    Wang, Yulong; Tang, Yuan Yan; Li, Luoqing

    2017-06-01

    As an efficient sparse representation algorithm, orthogonal matching pursuit (OMP) has attracted massive attention in recent years. However, OMP and most of its variants estimate the sparse vector using the mean square error criterion, which depends on the Gaussianity assumption of the error distribution. A violation of this assumption, e.g., non-Gaussian noise, may lead to performance degradation. In this paper, a correntropy matching pursuit (CMP) method is proposed to alleviate this problem of OMP. Unlike many other matching pursuit methods, our method is independent of the error distribution. We show that CMP can adaptively assign small weights on severely corrupted entries of data and large weights on clean ones, thus reducing the effect of large noise. Our another contribution is to develop a robust sparse representation-based recognition method based on CMP. Experiments on synthetic and real data show the effectiveness of our method for both sparse approximation and pattern recognition, especially for noisy, corrupted, and incomplete data.

  1. Smoothing-norm preconditioning for GMRES

    DEFF Research Database (Denmark)

    Hansen, Per Christian; Jensen, Toke Koldborg

    2004-01-01

    When GMRES is applied to a discrete ill-posed problem with a square matrix, then the iterates can be considered as regularized solutions. We show how to precondition GMRES in such a way that the iterations take into account a smoothing norm for the solution. This technique is well established...... for CGLS, but it does not apply directly to GMRES. We develop a similar technique that works for GMRES, without the need for modifications of the smoothing norm, and which preserves symmetry if the coefficient matrix is symmetric. We also discuss the efficient implementation of our algorithm, and we...

  2. Reduction of snapshots for MIMO radar detection by block/group orthogonal matching pursuit

    KAUST Repository

    Ali, Hussain El Hosiny

    2014-10-01

    Multiple-input multiple-output (MIMO) radar works on the principle of transmission of independent waveforms at each element of its antenna array and is widely used for surveillance purposes. In this work, we investigate MIMO radar target localization problem with compressive sensing. Specifically, we try to solve the problem of estimation of target location in MIMO radar by group and block sparsity algorithms. It will lead us to a reduced number of snapshots required and also we can achieve better radar resolution. We will use group orthogonal matching pursuit (GOMP) and block orthogonal matching pursuit (BOMP) for our problem. © 2014 IEEE.

  3. Cinematographic analysis of vascular smooth muscle cell interactions with extracellular matrix.

    Science.gov (United States)

    Absher, M; Baldor, L

    1991-01-01

    The interactions of vascular smooth muscle cells with growth modulators and extracellular matrix molecules may play a role in the proliferation and migration of these cells after vascular injury and during the development of atherosclerosis. Time-lapse cinematographic techniques have been used to study cell division and migration of bovine carotid artery smooth muscle cells in response to matrix molecules consisting of solubilized basement membrane (Matrigel) and type I collagen. When cells were grown adjacent to Matrigel, both migration and cell proliferation were increased and interdivision time was shortened. Cells grown in Matrigel or in type I collagen had markedly reduced migration rates but interdivision time was not altered. Further, diffusible components of the Matrigel were found to stimulate proliferation of the smooth muscle cells.

  4. PHANTOM: Smoothed particle hydrodynamics and magnetohydrodynamics code

    Science.gov (United States)

    Price, Daniel J.; Wurster, James; Nixon, Chris; Tricco, Terrence S.; Toupin, Stéven; Pettitt, Alex; Chan, Conrad; Laibe, Guillaume; Glover, Simon; Dobbs, Clare; Nealon, Rebecca; Liptai, David; Worpel, Hauke; Bonnerot, Clément; Dipierro, Giovanni; Ragusa, Enrico; Federrath, Christoph; Iaconi, Roberto; Reichardt, Thomas; Forgan, Duncan; Hutchison, Mark; Constantino, Thomas; Ayliffe, Ben; Mentiplay, Daniel; Hirsh, Kieran; Lodato, Giuseppe

    2017-09-01

    Phantom is a smoothed particle hydrodynamics and magnetohydrodynamics code focused on stellar, galactic, planetary, and high energy astrophysics. It is modular, and handles sink particles, self-gravity, two fluid and one fluid dust, ISM chemistry and cooling, physical viscosity, non-ideal MHD, and more. Its modular structure makes it easy to add new physics to the code.

  5. Autophagic regulation of smooth muscle cell biology

    Directory of Open Access Journals (Sweden)

    Joshua K. Salabei

    2015-04-01

    Full Text Available Autophagy regulates the metabolism, survival, and function of numerous cell types, including those comprising the cardiovascular system. In the vasculature, changes in autophagy have been documented in atherosclerotic and restenotic lesions and in hypertensive vessels. The biology of vascular smooth muscle cells appears particularly sensitive to changes in the autophagic program. Recent evidence indicates that stimuli or stressors evoked during the course of vascular disease can regulate autophagic activity, resulting in modulation of VSMC phenotype and viability. In particular, certain growth factors and cytokines, oxygen tension, and pharmacological drugs have been shown to trigger autophagy in smooth muscle cells. Importantly, each of these stimuli has a redox component, typically associated with changes in the abundance of reactive oxygen, nitrogen, or lipid species. Collective findings support the hypothesis that autophagy plays a critical role in vascular remodeling by regulating smooth muscle cell phenotype transitions and by influencing the cellular response to stress. In this graphical review, we summarize current knowledge on the role of autophagy in the biology of the smooth muscle cell in (pathophysiology.

  6. Interval Forecast for Smooth Transition Autoregressive Model ...

    African Journals Online (AJOL)

    In this paper, we propose a simple method for constructing interval forecast for smooth transition autoregressive (STAR) model. This interval forecast is based on bootstrapping the residual error of the estimated STAR model for each forecast horizon and computing various Akaike information criterion (AIC) function. This new ...

  7. Data driven smooth tests for composite hypotheses

    NARCIS (Netherlands)

    Inglot, Tadeusz; Kallenberg, W.C.M.; Ledwina, Teresa

    1997-01-01

    The classical problem of testing goodness-of-fit of a parametric family is reconsidered. A new test for this problem is proposed and investigated. The new test statistic is a combination of the smooth test statistic and Schwarz's selection rule. More precisely, as the sample size increases, an

  8. The Koch curve as a smooth manifold

    International Nuclear Information System (INIS)

    Epstein, Marcelo; Sniatycki, Jedrzej

    2008-01-01

    We show that there exists a homeomorphism between the closed interval [0,1] is contained in R and the Koch curve endowed with the subset topology of R 2 . We use this homeomorphism to endow the Koch curve with the structure of a smooth manifold with boundary

  9. Modified Artificial Viscosity in Smooth Particle Hydrodynamics

    OpenAIRE

    Selhammar, Magnus

    1996-01-01

    Artificial viscosity is needed in Smooth Particle Hydrodynamics to prevent interparticle penetration, to allow shocks to form and to damp post shock oscillations. Artificial viscosity may, however, lead to problems such as unwanted heating and unphysical solutions. A modification of the standard artificial viscosity recipe is proposed which reduces these problems. Some test cases discussed.

  10. Smoothness in Banach spaces. Selected problems

    Czech Academy of Sciences Publication Activity Database

    Fabian, Marián; Montesinos, V.; Zizler, Václav

    2006-01-01

    Roč. 100, č. 2 (2006), s. 101-125 ISSN 1578-7303 R&D Projects: GA ČR(CZ) GA201/04/0090; GA AV ČR(CZ) IAA100190610 Institutional research plan: CEZ:AV0Z10190503 Keywords : smooth norm * renorming * weakly compactly generated space Subject RIV: BA - General Mathematics

  11. Full Waveform Inversion Using Nonlinearly Smoothed Wavefields

    KAUST Repository

    Li, Y.

    2017-05-26

    The lack of low frequency information in the acquired data makes full waveform inversion (FWI) conditionally converge to the accurate solution. An initial velocity model that results in data with events within a half cycle of their location in the observed data was required to converge. The multiplication of wavefields with slightly different frequencies generates artificial low frequency components. This can be effectively utilized by multiplying the wavefield with itself, which is nonlinear operation, followed by a smoothing operator to extract the artificially produced low frequency information. We construct the objective function using the nonlinearly smoothed wavefields with a global-correlation norm to properly handle the energy imbalance in the nonlinearly smoothed wavefield. Similar to the multi-scale strategy, we progressively reduce the smoothing width applied to the multiplied wavefield to welcome higher resolution. We calculate the gradient of the objective function using the adjoint-state technique, which is similar to the conventional FWI except for the adjoint source. Examples on the Marmousi 2 model demonstrate the feasibility of the proposed FWI method to mitigate the cycle-skipping problem in the case of a lack of low frequency information.

  12. On the theory of smooth structures. 2

    International Nuclear Information System (INIS)

    Shafei Deh Abad, A.

    1992-09-01

    In this paper we continue by introducing the concepts of substructures, quotient structures and tensor product, and examine some of their properties. By using the concept of tensor product, in the next paper, we will give another product for smooth structures which is a characterization of integral domains which are not fields. (author). 2 refs

  13. multiscale smoothing in supervised statistical learning

    Indian Academy of Sciences (India)

    Examples of supervised learning. Diabetes data : Measurements are taken on fasting plasma glucose ... and uses the training data to estimate its parameters. Linear Discriminant Analysis (LDA). Quadratic Discriminant Analysis ... Standard methods for smoothing parameter selection. Maximization of the likelihood function ( ...

  14. The social costs of extrinsic relative to intrinsic goal pursuits: their relation with social dominance and racial and ethnic prejudice.

    Science.gov (United States)

    Duriez, Bart; Vansteenkiste, Maarten; Soenens, Bart; De Witte, Hans

    2007-08-01

    Self-determination theory's distinction between extrinsic and intrinsic goal pursuits offers a possible explanation for ethnic and racial prejudice. Because extrinsic relative to intrinsic goal pursuits (E/I) stimulate interpersonal competition, they were expected to predict social dominance orientation (SDO), which, in turn, would predict racial and ethnic prejudice. Results of a first cross-sectional study showed that E/I goal pursuits are positively associated with prejudice and that SDO partially mediates this association. In a second longitudinal study, we replicated these results. In addition, however, we found evidence for a reciprocal relationship between E/I goal pursuit and SDO. Moreover, both E/I goal pursuit and SDO had an independent effect on increases in prejudice. Implications of these findings are discussed.

  15. Effects of Bronchial Thermoplasty on Airway Smooth Muscle and Collagen Deposition in Asthma.

    Science.gov (United States)

    Chakir, Jamila; Haj-Salem, Ikhlass; Gras, Delphine; Joubert, Philippe; Beaudoin, Ève-Léa; Biardel, Sabrina; Lampron, Noel; Martel, Simon; Chanez, Pascal; Boulet, Louis-Philippe; Laviolette, Michel

    2015-11-01

    The aim of bronchial thermoplasty is to improve asthma symptoms by reducing central airway smooth muscle mass. Up to now, the reduction of smooth muscle mass has been documented for only 1 group of 10 patients who had 15% or more of their pretreatment total bronchial biopsy area occupied by smooth muscle. To evaluate the effects of bronchial thermoplasty on airway smooth muscle mass and airway collagen deposition in adult patients with asthma, regardless of pretreatment smooth muscle area. Seventeen patients with asthma underwent bronchial thermoplasty over the course of three visits. At Visit 1, bronchial biopsies were taken from the lower lobe that was not treated during this session. At Visit 2 (3-14 wk after the first visit), all 17 patients underwent biopsy of the lower lobe treated during the first procedure. At Visit 3 (7-22 wk after the first visit), nine patients agreed to undergo biopsy of the same lower lobe. Histological and immunohistochemical analyses were performed on the biopsy specimens. Bronchial thermoplasty decreased airway smooth muscle from 12.9 ± 1.2% of the total biopsy surface at Visit 1 to 4.6 ± 0.8% at Visit 2 (P Bronchial thermoplasty also decreased Type I collagen deposition underneath the basement membrane from 6.8 ± 0.3 μm at Visit 1 to 4.3 ± 0.2 μm at Visit 2 (P bronchial thermoplasty reduced the smooth muscle mass of treated airway segments, regardless of the baseline level of muscle mass. Treatment also altered the deposition of collagen. At follow-up, bronchial thermoplasty improved asthma control; however, the limited number of subjects did not allow us to evaluate possible correlations between these improvements and the studied histological parameters. Further studies are needed to confirm these results and evaluate their persistence.

  16. Captopril augments acetylcholine-induced bronchial smooth muscle contractions in vitro via kinin-dependent mechanisms.

    Science.gov (United States)

    Agrawal, Naman; Akella, Aparna; Deshpande, Shripad B

    2016-06-01

    Angiotensin converting enzyme (ACE) inhibitors therapy is aassociated with bothersome dry cough as an adverse effect. The mechanisms underlying this adverse effect are not clear. Therefore, influence of captopril (an ACE inhibitor) on acetylcholine (ACh)-induced bronchial smooth muscle contractions was investigated. Further, the mechanisms underlying the captopril-induced changes were also explored. In vitro contractions of rat bronchial smooth muscle to cumulative concentrations of ACh were recorded before and after exposure to captopril. Further, the involvement of kinin and inositol triphosphate (IP₃) pathways for captopril-induced alterations were explored. ACh produced concentration-dependent (5-500 µM) increase in bronchial smooth muscle contractions. Pre-treatment with captopril augmented the ACh-induced contractions at each concentration significantly. Pre-treatment with aprotinin (kinin synthesis inhibitor) or heparin (inositol triphosphate, IP₃-inhibitor), blocked the captopril-induced augmentation of bronchial smooth muscle contractions evoked by ACh. Further, captopril-induced augmentation was absent in calcium-free medium. These results suggest that captopril sensitizes bronchial smooth muscles to ACh-induced contractions. This sensitization may be responsible for dry cough associated with captopril therapy.

  17. In Pursuit of the Primitive: Van der Post's Lost World | Klopper ...

    African Journals Online (AJOL)

    I begin by looking at the genre of travel writing in the context of ethnographic writing, and suggest that the guiding trope of the text, the pursuit of the primitive in the face of its imminent disappearance by the mid-twentieth century, is characteristic of much travel writing of the period. I ask whether it is possible, from the ...

  18. Dynamics of the echolocation beam during prey pursuit in aerial hawking bats.

    Science.gov (United States)

    Jakobsen, Lasse; Olsen, Mads Nedergaard; Surlykke, Annemarie

    2015-06-30

    In the evolutionary arms race between prey and predator, measures and countermeasures continuously evolve to increase survival on both sides. Bats and moths are prime examples. When exposed to intense ultrasound, eared moths perform dramatic escape behaviors. Vespertilionid and rhinolophid bats broaden their echolocation beam in the final stage of pursuit, presumably as a countermeasure to keep evading moths within their "acoustic field of view." In this study, we investigated if dynamic beam broadening is a general property of echolocation when catching moving prey. We recorded three species of emballonurid bats, Saccopteryx bilineata, Saccopteryx leptura, and Rhynchonycteris naso, catching airborne insects in the field. The study shows that S. bilineata and S. leptura maintain a constant beam shape during the entire prey pursuit, whereas R. naso broadens the beam by lowering the peak call frequency from 100 kHz during search and approach to 67 kHz in the buzz. Surprisingly, both Saccopteryx bats emit calls with very high energy throughout the pursuit, up to 60 times more than R. naso and Myotis daubentonii (a similar sized vespertilionid), providing them with as much, or more, peripheral "vision" than the vespertilionids, but ensonifying objects far ahead suggesting more clutter. Thus, beam broadening is not a fundamental property of the echolocation system. However, based on the results, we hypothesize that increased peripheral detection is crucial to all aerial hawking bats in the final stages of prey pursuit and speculate that beam broadening is a feature characterizing more advanced echolocation.

  19. A Biopsychosocial Model of Disordered Eating and the Pursuit of Muscularity in Adolescent Boys

    Science.gov (United States)

    Ricciardelli, Lina A.; McCabe, Marita P.

    2004-01-01

    This review provides an evaluation of the correlates and/or risk factors associated with disordered eating and the pursuit of muscularity among adolescent boys. One of the main conclusions is that similar factors and processes are associated with both behavioral problems. Several factors found to be consistently associated with disordered eating…

  20. Users manual. Pursuit program of use licenses of radioactive material or generator equipment of ionizing radiations

    International Nuclear Information System (INIS)

    Becerril M, V.M.; Villarreal, J.E.

    1992-05-01

    The objective of the program 'Databases for the pursuit of licenses of use of radioactive material', it consists on the application of a computer system carried out in dbase IV that it allows the control of the all the information related with those licenses for use, possession and storage of radioactive material or generator equipment of ionizing radiations. (Author)

  1. In Pursuit of a Connected Way of Knowing: The Case of One Mathematics Teacher

    Science.gov (United States)

    Agudelo-Valderrama, Cecilia; Martínez, Diana

    2016-01-01

    In this paper, we offer illustrations of a mathematics teacher's difficulties with content knowledge when trying to find connections between school mathematics and science; we do so by describing the development of this teacher's thinking and learning in her pursuit of connections between the concepts of slope of a line and density of matter. The…

  2. In Pursuit of Ethical Research: Studying Hybrid Communities Using Online and Face-to-Face Communications

    Science.gov (United States)

    Busher, Hugh; James, Nalita

    2015-01-01

    Hybrid communities using online and face-to-face communications to construct their practices are increasingly part of everyday life amongst people who have easy access to the internet. Researching these communities raises a number of challenges for researchers in the pursuit of ethical research. The paper begins by exploring what is understood by…

  3. Regional environmental law : Transregional comparative lessons in pursuit of sustainable development

    NARCIS (Netherlands)

    Scholtz, Werner; Verschuuren, Jonathan

    This perceptive work presents a unique comparative legal analysis, ascertaining how regional environmental law can contribute to the prevailing pursuit of global sustainable development. The book provides an introduction to and analysis of the environmental law adhered by each regional organisation

  4. PURSUIT ROTOR PERFORMANCE, 1. EFFECTS OF REINFORCING THE LONGER INTERVALS OF CONTINUOUS TRACKING WITHIN EACH TRIAL.

    Science.gov (United States)

    BJORKLUND, JOHN F.; SHELDON, RICHARD W.

    TO DETERMINE WHETHER SELECTIVE REINFORCEMENT OF PURSUIT ROTOR PERFORMANCE FACILITATES ACQUISITION OF SKILL AND PROMOTES ITS RETENTION, FIVE GROUPS OF SUBJECTS WERE INDIVIDUALLY TRAINED FOR TEN SESSIONS OF 15 TRIALS EACH. SELECTIVE REINFORCEMENT OF LONGER THAN AVERAGE TARGET CONTACTS WAS INTRODUCED FOR ONE GROUP OF SUBJECTS DURING SESSIONS SIX AND…

  5. Home and Motivational Factors Related to Science-Career Pursuit: Gender Differences and Gender Similarities

    Science.gov (United States)

    Shin, Jongho; Lee, Hyunjoo; McCarthy-Donovan, Alexander; Hwang, Hyeyoung; Yim, Sonyoung; Seo, EunJin

    2015-01-01

    The purpose of the study was to examine whether gender differences exist in the mean levels of and relations between adolescents' home environments (parents' view of science, socio-economic status (SES)), motivations (intrinsic and instrumental motivations, self-beliefs), and pursuit of science careers. For the purpose, the Programmed for…

  6. The Role of Intrinsic Motivation in the Academic Pursuits of Nontraditional Students

    Science.gov (United States)

    Shillingford, Shani; Karlin, Nancy J.

    2013-01-01

    This article examines the role of intrinsic motivation in the academic pursuits of nontraditional students. The Academic Motivational Scale (AMS) was administered to 35 undergraduate students, 6 males and 29 females, aged 25 to 49 to explore their motivational orientations in choosing to attend college. The results of the study show that…

  7. Intellectual Pursuits of Young Children through Picture Book Literacy, Focusing on Italian Preschools

    Science.gov (United States)

    Beltchenko, Laura

    2016-01-01

    In this article, I will examine the use of picture books as a means of supporting the intellectual pursuits of young children. Theoretical frameworks will be discussed as they pertain to the integration of these books in the Municipal Infant Toddler Centers and Preschools of Reggio Emilia and Pistoia, Italy. The pedagogical framework of these…

  8. Career Pursuit Pathways among Emerging Adult Men and Women: Psychosocial Correlates and Precursors

    Science.gov (United States)

    Shulman, Shmuel; Barr, Tamuz; Livneh, Yaara; Nurmi, Jari-Erik; Vasalampi, Kati; Pratt, Michael

    2015-01-01

    The present study examined career pursuit pathways in 100 Israeli emerging adults (54 men) who were followed from age 22 to 29. Employing a semi-structured interview at the age of 29, participants were asked about current work and educational status, work and educational goals and status changes in recent years, and to reflect on the meaning of…

  9. Coping with spinal cord injury: Tenacious goal pursuit and flexible goal adjustment.

    NARCIS (Netherlands)

    van Lankveld, Wim; van Diemen, Tijn; van Nes, Ilse J. W.

    2011-01-01

    Objective: To investigate the correlation of higher-order coping strategies of tenacious goal pursuit and flexible goal adjustment with adjustment after rehabilitation in spinal cordinjury. Design: Cross-sectional correlational study.Subjects/patients: All 397 eligible patients entered for spinal

  10. Extrinsic relative to intrinsic goal pursuits and peer dynamics: selection and influence processes among adolescents.

    Science.gov (United States)

    Duriez, Bart; Giletta, Matteo; Kuppens, Peter; Vansteenkiste, Maarten

    2013-10-01

    Self-Determination Theory discerns goals and values in terms of whether they are intrinsic or extrinsic in nature. Although research substantiates the importance of goal preferences for a host of outcomes, few studies examined how such preferences develop, and studies that did pay attention to this focused on parental influence processes. The present study focuses on the role of peers. Social network analyses on longitudinal data gathered among senior high-school students (N = 695) confirm that peer similarity in goal pursuit exists, and that, although this similarity partly originates from adolescents selecting friends on the basis of perceived goal pursuit similarity, it also results from peers actively influencing each other. Hence, friends tend to become more alike in terms of goal pursuit over time. Data also suggest that, although changes in goal pursuit at this age can be predicted from peer dynamics, they cannot be attributed to parental goal promotion efforts. Copyright © 2013 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  11. Singapore Primary Students' Pursuit of Multiple Achievement Goals: A Latent Profile Analysis

    Science.gov (United States)

    Ning, Hoi Kwan

    2018-01-01

    Based on measures of approach and avoidance mastery and performance goals delineated in the 2 × 2 achievement goal framework, this study utilized a person-centered approach to examine Singapore primary students' (N = 819) multiple goals pursuit in the general school context. Latent profile analysis identified six types of students with distinct…

  12. Pursuit of Excellence in a Networked Society. : Theoretical and Practical Approaches.

    NARCIS (Netherlands)

    J. J.J.M. Volker; Dr. Marca Wolfensberger; Drs. L. Drayer

    2014-01-01

    Pursuit of Excellence in a Networked Society gives an overview of research and practice, describing and exploring efforts toward continuous improvement in programming to promote excellence. The talent development of students and teachers is a hot topic in today’s knowledge-based society which

  13. The Role of an Epistemology of Inclusivity on the Pursuit of Social Justice: A Case Study

    Science.gov (United States)

    Scanlan, Martin

    2012-01-01

    Social justice education emphasizes how schools can better serve traditionally marginalized students. This case study examines the pursuit of social justice education in an unlikely setting: a Catholic elementary school that both espouses inclusion of all children and effectively includes children with a wide range of disabilities. The article…

  14. School factors affecting postsecondary career pursuits of high-achieving girls in mathematics and science

    Science.gov (United States)

    Yoo, Hyunsil

    This study examined the influences of secondary school experiences of high-achieving girls in math and science on their postsecondary career pursuits in science fields. Specifically, using the National Education Longitudinal Study of 1988 (NELS:88), the study investigated how science class experiences in high school affect science career persistence of high-achieving girls over and above personal and family factors. Selecting the top 10% on the 8 th grade math and science achievement tests from two panel samples of 1988--1994 and 1988--2000, this study examined which science instructional experiences (i.e., lecture-oriented, experiment-oriented, and student-oriented) best predicted college major choices and postsecondary degree attainments in the fields of science after controlling for personal and family factors. A two-stage test was employed for the analysis of each panel sample. The first test examined the dichotomous career pursuits between science careers and non-science careers and the second test examined the dichotomous pursuits within science careers: "hard" science and "soft" science. Logistic regression procedures were used with consideration of panel weights and design effects. This study identified that experiment-oriented and student-oriented instructional practices seem to positively affect science career pursuits of high-achieving females, while lecture-oriented instruction negatively affected their science career pursuits, and that the longitudinal effects of the two positive instructional contributors to science career pursuits appear to be differential between major choice and degree attainment. This study also found that the influences of instructional practices seem to be slight for general females, while those for high-achieving females were highly considerable, regardless of whether negative or positive. Another result of the study found that only student-oriented instruction seemed to have positive effects for high-achieving males. In

  15. When hawks attack: animal-borne video studies of goshawk pursuit and prey-evasion strategies.

    Science.gov (United States)

    Kane, Suzanne Amador; Fulton, Andrew H; Rosenthal, Lee J

    2015-01-15

    Video filmed by a camera mounted on the head of a Northern Goshawk (Accipiter gentilis) was used to study how the raptor used visual guidance to pursue prey and land on perches. A combination of novel image analysis methods and numerical simulations of mathematical pursuit models was used to determine the goshawk's pursuit strategy. The goshawk flew to intercept targets by fixing the prey at a constant visual angle, using classical pursuit for stationary prey, lures or perches, and usually using constant absolute target direction (CATD) for moving prey. Visual fixation was better maintained along the horizontal than vertical direction. In some cases, we observed oscillations in the visual fix on the prey, suggesting that the goshawk used finite-feedback steering. Video filmed from the ground gave similar results. In most cases, it showed goshawks intercepting prey using a trajectory consistent with CATD, then turning rapidly to attack by classical pursuit; in a few cases, it showed them using curving non-CATD trajectories. Analysis of the prey's evasive tactics indicated that only sharp sideways turns caused the goshawk to lose visual fixation on the prey, supporting a sensory basis for the surprising frequency and effectiveness of this tactic found by previous studies. The dynamics of the prey's looming image also suggested that the goshawk used a tau-based interception strategy. We interpret these results in the context of a concise review of pursuit-evasion in biology, and conjecture that some prey deimatic 'startle' displays may exploit tau-based interception. © 2015. Published by The Company of Biologists Ltd.

  16. Single Image Super-Resolution via L0 Image Smoothing

    OpenAIRE

    Liu, Zhang; Huang, Qi; Li, Jian; Wang, Qi

    2014-01-01

    We propose a single image super-resolution method based on a L0 smoothing approach. We consider a low-resolution image as two parts: one is the smooth image generated by the L0 smoothing method and the other is the error image between the low-resolution image and the smoothing image. We get an intermediate high-resolution image via a classical interpolation and then generate a high-resolution smoothing image with sharp edges by the L0 smoothing method. For the error image, a...

  17. Inhibition of extracellular matrix production and remodeling by doxycycline in smooth muscle cells

    OpenAIRE

    Rogelio Palomino-Morales; Carolina Torres; Sonia Perales; Ana Linares; Maria Jose Alejandre

    2016-01-01

    Alterations in the extracellular matrix (ECM) production and remodeling of smooth muscle cells (SMCs) have been implicated in processes related to the differentiation in atherosclerosis. Due to the anti-atherosclerotic properties of the tetracyclines, we aimed to investigate whether cholesterol supplementation changes the effect of doxycycline over the ECM proteins synthesis and whether isoprenylated proteins and Rho A protein activation are affected. SMC primary culture isolated from chicks ...

  18. Single Locus Maintains Large Variation of Sex Reversal in Half-Smooth Tongue Sole (Cynoglossus semilaevis)

    OpenAIRE

    Jiang, Li; Li, Hengde

    2016-01-01

    Sex determination is a fundamental biological process for individual sex development and population sex ratios. However, for some species, the primary sex might be altered during development, and individuals can develop into the opposite sex. Sex reversal may happen in insects, reptiles, amphibians, and fishes. In half-smooth tongue sole (Cynoglossus semilaevis), some genetically female fish irreversibly reverse to pseudomales, resulting in higher costs in aquaculture owing to a lower growth ...

  19. S100A12 and the Airway Smooth Muscle: Beyond Inflammation and Constriction

    OpenAIRE

    Camoretti-Mercado, Blanca; Karrar, Eltayeb; Nu?ez, Luis; Bowman, Marion A Hofmann

    2012-01-01

    Airway inflammation, lung remodeling, and Airway Hyperresponsiveness (AHR) are major features of asthma and Chronic Obstructive Pulmonary Disease (COPD). The inflammatory response to allergens, air pollutants, and other insults is likely to play a key role in promoting structural changes in the lung including the overabundance of Airway Smooth Muscle (ASM) seen in asthmatics. These alterations or remodeling could, in turn, impact the immunmodulatory actions of the ASM, the ASM's contractile p...

  20. Smectite alteration

    International Nuclear Information System (INIS)

    Anderson, D.M.

    1984-11-01

    This report contains the proceedings of a second workshop in Washington DC December 8-9, 1983 on the alteration of smectites intended for use as buffer materials in the long-term containment of nuclear wastes. It includes extended summaries of all presentations and a transcript of the detailed scientific discussion. The discussions centered on three main questions: What is the prerequisite for and what is the precise mechanism by which smectite clays may be altered to illite. What are likly sources of potassium with respect to the KBS project. Is it likely that the conversion of smectite to illite will be of importance in the 10 5 to the 10 6 year time frame. The workshop was convened to review considerations and conclusions in connection to these questions and also to broaden the discussion to consider the use of smectite clays as buffer materials for similar applications in different geographical and geological settings. SKBF/KBS technical report 83-03 contains the proceedings from the first workshop on these matters that was held at the State University of New York, Buffalo May 26-27, 1982. (Author)

  1. A smoothing algorithm using cubic spline functions

    Science.gov (United States)

    Smith, R. E., Jr.; Price, J. M.; Howser, L. M.

    1974-01-01

    Two algorithms are presented for smoothing arbitrary sets of data. They are the explicit variable algorithm and the parametric variable algorithm. The former would be used where large gradients are not encountered because of the smaller amount of calculation required. The latter would be used if the data being smoothed were double valued or experienced large gradients. Both algorithms use a least-squares technique to obtain a cubic spline fit to the data. The advantage of the spline fit is that the first and second derivatives are continuous. This method is best used in an interactive graphics environment so that the junction values for the spline curve can be manipulated to improve the fit.

  2. The Smooth Muscle of the Artery

    Science.gov (United States)

    1975-01-01

    experiments which we carried out showed that a]- though the overall aminoacid composition of the structural glycc- proteins isolated from-various...H., Baudouin-Legros, K1.: Cal- cium antagonism of sodium nitronrusside in vascular smooth muscle. Pflugers Arch. 339, 56, 1973. 192. Krut, L.H...Wall Glycoproteis, and Streptococcus A Cll 1M4brane. Tramplant. Proc. 4: 415-418, 1972. -- I1 286. Robert, L., Coote, P.: Aminoacid Composition of

  3. Does responsive pricing smooth demand shocks?

    OpenAIRE

    Pascal, Courty; Mario, Pagliero

    2011-01-01

    Using data from a unique pricing experiment, we investigate Vickrey’s conjecture that responsive pricing can be used to smooth both predictable and unpredictable demand shocks. Our evidence shows that increasing the responsiveness of price to demand conditions reduces the magnitude of deviations in capacity utilization rates from a pre-determined target level. A 10 percent increase in price variability leads to a decrease in the variability of capacity utilization rates between...

  4. Equivariant embeddings into smooth toric varieties

    OpenAIRE

    Hausen, Juergen

    2000-01-01

    We characterize embeddability of algebraic varieties into smooth toric varieties and prevarieties. Our embedding results hold also in an equivariant context and thus generalize a well known embedding theorem of Sumihiro on quasiprojective G-varieties. The main idea is to reduce the embedding problem to the affine case. This is done by constructing equivariant affine conoids, a tool which extends the concept of an equivariant affine cone over a projective G-variety to a more general framework.

  5. Smooth Nb surfaces fabricated by buffered electropolishing

    International Nuclear Information System (INIS)

    Wu, Andy T.; Mammosser, John; Phillips, Larry; Delayen, Jean; Reece, Charles; Wilkerson, Amy; Smith, David; Ike, Robert

    2007-01-01

    It was demonstrated that smooth Nb surfaces could be obtained through buffered electropolishing (BEP) employing an electrolyte consisting of lactic, sulfuric, and hydrofluoric acids. Parameters that control the polishing process were optimized to achieve a smooth surface finish. The polishing rate of BEP was determined to be 0.646 μm/min which was much higher than 0.381 μm/min achieved by the conventional electropolishing (EP) process widely used in the superconducting radio frequency (SRF) community. Root mean square measurements using a 3D profilometer revealed that Nb surfaces treated by BEP were an order of magnitude smoother than those treated by the optimized EP process. The chemical composition of the Nb surfaces after BEP was analyzed by static and dynamic secondary ion mass spectrometry (SIMS) systems. SIMS results implied that the surface oxide structure of Nb might be more complicated than what usually believed and could be inhomogeneous. Preliminary results of BEP on Nb SRF single cell cavities and half-cells were reported. It was shown that smooth and bright surfaces could be obtained in 1800 s when the electric field inside a SRF cavity was uniform during a BEP process. This study showed that BEP is a promising technique for surface treatment on Nb SRF cavities to be used in particle accelerators

  6. Log canonical thresholds of smooth Fano threefolds

    International Nuclear Information System (INIS)

    Cheltsov, Ivan A; Shramov, Konstantin A

    2008-01-01

    The complex singularity exponent is a local invariant of a holomorphic function determined by the integrability of fractional powers of the function. The log canonical thresholds of effective Q-divisors on normal algebraic varieties are algebraic counterparts of complex singularity exponents. For a Fano variety, these invariants have global analogues. In the former case, it is the so-called α-invariant of Tian; in the latter case, it is the global log canonical threshold of the Fano variety, which is the infimum of log canonical thresholds of all effective Q-divisors numerically equivalent to the anticanonical divisor. An appendix to this paper contains a proof that the global log canonical threshold of a smooth Fano variety coincides with its α-invariant of Tian. The purpose of the paper is to compute the global log canonical thresholds of smooth Fano threefolds (altogether, there are 105 deformation families of such threefolds). The global log canonical thresholds are computed for every smooth threefold in 64 deformation families, and the global log canonical thresholds are computed for a general threefold in 20 deformation families. Some bounds for the global log canonical thresholds are computed for 14 deformation families. Appendix A is due to J.-P. Demailly.

  7. Nodular smooth muscle metaplasia in multiple peritoneal endometriosis

    OpenAIRE

    Kim, Hyun-Soo; Yoon, Gun; Ha, Sang Yun; Song, Sang Yong

    2015-01-01

    We report here an unusual presentation of peritoneal endometriosis with smooth muscle metaplasia as multiple protruding masses on the lateral pelvic wall. Smooth muscle metaplasia is a common finding in rectovaginal endometriosis, whereas in peritoneal endometriosis, smooth muscle metaplasia is uncommon and its nodular presentation on the pelvic wall is even rarer. To the best of our knowledge, this is the first case of nodular smooth muscle metaplasia occurring in peritoneal endometriosis. A...

  8. Moving least-squares corrections for smoothed particle hydrodynamics

    OpenAIRE

    Bilotta, G.; Russo, G.; Herault, A.; Del Negro, C.

    2011-01-01

    First-order moving least-squares are typically used in conjunction with smoothed particle hydrodynamics in the form of post-processing filters for density fields, to smooth out noise that develops in most applications of smoothed particle hydrodynamics. We show how an approach based on higher-order moving least-squares can be used to correct some of the main limitations in gradient and second-order derivative computation in classic smoothed particle hydrodynamics formulations. With a small in...

  9. Hypoxic contraction of cultured pulmonary vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Murray, T.R.; Chen, L.; Marshall, B.E.; Macarak, E.J.

    1990-01-01

    The cellular events involved in generating the hypoxic pulmonary vasoconstriction response are not clearly understood, in part because of the multitude of factors that alter pulmonary vascular tone. The goal of the present studies was to determine if a cell culture preparation containing vascular smooth muscle (VSM) cells could be made to contract when exposed to a hypoxic atmosphere. Cultures containing only fetal bovine pulmonary artery VSM cells were assessed for contractile responses to hypoxic stimuli by two methods. In the first, tension forces generated by cells grown on a flexible growth surface (polymerized polydimethyl siloxane) were manifested as wrinkles and distortions of the surface under the cells. Wrinkling of the surface was noted to progressively increase with time as the culture medium bathing the cells was made hypoxic (PO2 approximately 25 mmHg). The changes were sometimes reversible upon return to normoxic conditions and appeared to be enhanced in cells already exhibiting evidence of some baseline tone. Repeated passage in culture did not diminish the hypoxic response. Evidence for contractile responses to hypoxia was also obtained from measurements of myosin light chain (MLC) phosphorylation. Conversion of MLC to the phosphorylated species is an early step in the activation of smooth muscle contraction. Lowering the PO2 in the culture medium to 59 mmHg caused a 45% increase in the proportion of MLC in the phosphorylated form as determined by two-dimensional gel electrophoresis. Similarly, cultures preincubated for 4 h with 32P and then exposed to normoxia or hypoxia for a 5-min experimental period showed more than twice as much of the label in MLCs of the hypoxic cells

  10. Alternative Smoothing and Scaling Strategies for Weighted Composite Scores

    Science.gov (United States)

    Moses, Tim

    2014-01-01

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

  11. Smoothing-Norm Preconditioning for Regularizing Minimum-Residual Methods

    DEFF Research Database (Denmark)

    Hansen, Per Christian; Jensen, Toke Koldborg

    2006-01-01

    take into account a smoothing norm for the solution. This technique is well established for CGLS, but it does not immediately carry over to minimum-residual methods when the smoothing norm is a seminorm or a Sobolev norm. We develop a new technique which works for any smoothing norm of the form $\\|L...

  12. Breakpoint identification and smoothing of array comparative genomic hybridization data

    NARCIS (Netherlands)

    Jong, C.; Marchiori, E.; Meijer, G.J.; van der Vaart, A.W.; Ylstra, B.

    2004-01-01

    Summary: We describe a tool, called aCGH-Smooth, for the automated identification of breakpoints and smoothing of microarray comparative genomic hybridization (array CGH) data. aCGH-Smooth is written in visual C++, has a user-friendly interface including a visualization of the results and

  13. Smooth Fano polytopes can not be inductively constructed

    DEFF Research Database (Denmark)

    Øbro, Mikkel

    2008-01-01

    We examine a concrete smooth Fano 5-polytope $P$ with 8 vertices with the following properties: There does not exist a smooth Fano 5-polytope $Q$ with 7 vertices such that $P$ contains $Q$, and there does not exist a smooth Fano 5-polytope $R$ with 9 vertices such that $R$ contains $P$. As the po...

  14. Cardiac, skeletal, and smooth muscle mitochondrial respiration: are all mitochondria created equal?

    Science.gov (United States)

    Park, Song-Young; Gifford, Jayson R; Andtbacka, Robert H I; Trinity, Joel D; Hyngstrom, John R; Garten, Ryan S; Diakos, Nikolaos A; Ives, Stephen J; Dela, Flemming; Larsen, Steen; Drakos, Stavros; Richardson, Russell S

    2014-08-01

    Unlike cardiac and skeletal muscle, little is known about vascular smooth muscle mitochondrial respiration. Therefore, the present study examined mitochondrial respiratory rates in smooth muscle of healthy human feed arteries and compared with that of healthy cardiac and skeletal muscles. Cardiac, skeletal, and smooth muscles were harvested from a total of 22 subjects (53 ± 6 yr), and mitochondrial respiration was assessed in permeabilized fibers. Complex I + II, state 3 respiration, an index of oxidative phosphorylation capacity, fell progressively from cardiac to skeletal to smooth muscles (54 ± 1, 39 ± 4, and 15 ± 1 pmol·s(-1)·mg(-1), P muscles (222 ± 13, 115 ± 2, and 48 ± 2 μmol·g(-1)·min(-1), P respiration rates were normalized by CS (respiration per mitochondrial content), oxidative phosphorylation capacity was no longer different between the three muscle types. Interestingly, complex I state 2 normalized for CS activity, an index of nonphosphorylating respiration per mitochondrial content, increased progressively from cardiac to skeletal to smooth muscles, such that the respiratory control ratio, state 3/state 2 respiration, fell progressively from cardiac to skeletal to smooth muscles (5.3 ± 0.7, 3.2 ± 0.4, and 1.6 ± 0.3 pmol·s(-1)·mg(-1), P muscles suggest all mitochondria are created equal, the contrasting respiratory control ratio and nonphosphorylating respiration highlight the existence of intrinsic functional differences between these muscle mitochondria. This likely influences the efficiency of oxidative phosphorylation and could potentially alter ROS production.

  15. Vascular smooth muscle cell phenotypic changes in patients with Marfan syndrome.

    Science.gov (United States)

    Crosas-Molist, Eva; Meirelles, Thayna; López-Luque, Judit; Serra-Peinado, Carla; Selva, Javier; Caja, Laia; Gorbenko Del Blanco, Darya; Uriarte, Juan José; Bertran, Esther; Mendizábal, Yolanda; Hernández, Vanessa; García-Calero, Carolina; Busnadiego, Oscar; Condom, Enric; Toral, David; Castellà, Manel; Forteza, Alberto; Navajas, Daniel; Sarri, Elisabet; Rodríguez-Pascual, Fernando; Dietz, Harry C; Fabregat, Isabel; Egea, Gustavo

    2015-04-01

    Marfan's syndrome is characterized by the formation of ascending aortic aneurysms resulting from altered assembly of extracellular matrix microfibrils and chronic tissue growth factor (TGF)-β signaling. TGF-β is a potent regulator of the vascular smooth muscle cell (VSMC) phenotype. We hypothesized that as a result of the chronic TGF-β signaling, VSMC would alter their basal differentiation phenotype, which could facilitate the formation of aneurysms. This study explores whether Marfan's syndrome entails phenotypic alterations of VSMC and possible mechanisms at the subcellular level. Immunohistochemical and Western blotting analyses of dilated aortas from Marfan patients showed overexpression of contractile protein markers (α-smooth muscle actin, smoothelin, smooth muscle protein 22 alpha, and calponin-1) and collagen I in comparison with healthy aortas. VSMC explanted from Marfan aortic aneurysms showed increased in vitro expression of these phenotypic markers and also of myocardin, a transcription factor essential for VSMC-specific differentiation. These alterations were generally reduced after pharmacological inhibition of the TGF-β pathway. Marfan VSMC in culture showed more robust actin stress fibers and enhanced RhoA-GTP levels, which was accompanied by increased focal adhesion components and higher nuclear localization of myosin-related transcription factor A. Marfan VSMC and extracellular matrix measured by atomic force microscopy were both stiffer than their respective controls. In Marfan VSMC, both in tissue and in culture, there are variable TGF-β-dependent phenotypic changes affecting contractile proteins and collagen I, leading to greater cellular and extracellular matrix stiffness. Altogether, these alterations may contribute to the known aortic rigidity that precedes or accompanies Marfan's syndrome aneurysm formation. © 2015 American Heart Association, Inc.

  16. In the Pursuit of Sons: Additional Births or Sex-Selective Abortion in Pakistan?

    Science.gov (United States)

    Zaidi, Batool; Morgan, S Philip

    2016-12-01

    Even though Pakistan is a highly patriarchal society, it has not featured prominently in studies focusing on sex-selective abortion and sex ratios at birth. But with fertility declining and existing strong son preference-Pakistan has one of the highest desired sex ratios in the world-how will Pakistani families respond? In the pursuit of sons, will they have additional children or resort to sex-selective abortions? Or is there evidence that the pursuit of sons is weakening? Using data from three rounds of the demographic and health survey, we show clear evidence of son preference in fertility intentions, patterns of contraceptive use and parity progression ratios. More specifically, we find pervasive evidence that Pakistanis continue childbearing to have a son, to have more than one son and to have at least one daughter. We do not find consistent and convincing evidence that sex ratios at birth (which indicate sex-selective abortion) are increasing.

  17. Biomechanical justification of the choice of optimum mode for passing the individual pursuit race

    Directory of Open Access Journals (Sweden)

    A.N. Kolumbet

    2018-04-01

    Full Text Available Purpose : biomechanical justification of the choice of optimum mode of passing competitive distance of 4 km individual pursuit on track. Material : The qualified cyclists (n=14 participated in researches. The modified stationary cycle Monark was used. Cyclists performed work in two modes - A and B. Results : The mode B is physiologically more favorable. The mode B should be considered as a model of passing a distance in preliminary races of individual pursuit. Work in the mode A demands terminal mobilization of organism functions. Work in the mode A is more effective in the achievement of sports result. It can be used only once in the final race of competitions. Conclusions : The received data should be considered as a demonstration of specific features of passing a distance in the competitive modes. The tactical variant of competitive program creation is defined by the individual functional state.

  18. Research on rolling element bearing fault diagnosis based on genetic algorithm matching pursuit

    Science.gov (United States)

    Rong, R. W.; Ming, T. F.

    2017-12-01

    In order to solve the problem of slow computation speed, matching pursuit algorithm is applied to rolling bearing fault diagnosis, and the improvement are conducted from two aspects that are the construction of dictionary and the way to search for atoms. To be specific, Gabor function which can reflect time-frequency localization characteristic well is used to construct the dictionary, and the genetic algorithm to improve the searching speed. A time-frequency analysis method based on genetic algorithm matching pursuit (GAMP) algorithm is proposed. The way to set property parameters for the improvement of the decomposition results is studied. Simulation and experimental results illustrate that the weak fault feature of rolling bearing can be extracted effectively by this proposed method, at the same time, the computation speed increases obviously.

  19. Dynamics of the echolocation beam during prey pursuit in aerial hawking bats

    DEFF Research Database (Denmark)

    Jakobsen, Lasse; Olsen, Mads Nedergaard; Surlykke, Annemarie

    2015-01-01

    In the evolutionary arms race between prey and predator, measures and countermeasures continuously evolve to increase survival on both sides. Bats and moths are prime examples. When exposed to intense ultrasound, eared moths perform dramatic escape behaviors. Vespertilionid and rhinolophid bats...... of emballonurid bats, Saccopteryx bilineata, Saccopteryx leptura, and Rhynchonycteris naso, catching airborne insects in the field. The study shows that S. bilineata and S. leptura maintain a constant beam shape during the entire prey pursuit, whereas R. naso broadens the beam by lowering the peak call frequency...... from 100 kHz during search and approach to 67 kHz in the buzz. Surprisingly, both Saccopteryx bats emit calls with very high energy throughout the pursuit, up to 60 times more than R. naso and Myotis daubentonii (a similar sized vespertilionid), providing them with as much, or more, peripheral "vision...

  20. Stigmatizing materialism: on stereotypes and impressions of materialistic and experiential pursuits.

    Science.gov (United States)

    Van Boven, Leaf; Campbell, Margaret C; Gilovich, Thomas

    2010-04-01

    Five studies examined the stigmatization of materialism. Participants expressed negative stereotypes of materialistic people, considering them to be more selfish and self-centered than experiential people (Study 1). Participants also viewed materialistic pursuits as more extrinsically motivated than experiential pursuits (Study 2). These stereotypes led respondents from varied demographic backgrounds to form less favorable impressions of individuals who were associated with prototypically materialistic versus experiential purchases, a result that was statistically mediated by impressions that materialistic purchases were more extrinsically motivated (Study 3). These differential impressions are primarily attributable to the denigration of materialistic people rather than the admiration of experiential people (Study 4). The stigmatization of materialism led participants to like less and enjoy interacting less with their conversation partners when discussing materialistic rather than experiential purchases (Study 5). The authors discuss these findings' implications for self-perception, accurate social perception, and well-being.

  1. Matching-pursuit/split-operator Fourier-transform simulations of nonadiabatic quantum dynamics

    Science.gov (United States)

    Wu, Yinghua; Herman, Michael F.; Batista, Victor S.

    2005-03-01

    A rigorous and practical approach for simulations of nonadiabatic quantum dynamics is introduced. The algorithm involves a natural extension of the matching-pursuit/split-operator Fourier-transform (MP/SOFT) method [Y. Wu and V. S. Batista, J. Chem. Phys. 121, 1676 (2004)] recently developed for simulations of adiabatic quantum dynamics in multidimensional systems. The MP/SOFT propagation scheme, extended to nonadiabatic dynamics, recursively applies the time-evolution operator as defined by the standard perturbation expansion to first-, or second-order, accuracy. The expansion is implemented in dynamically adaptive coherent-state representations, generated by an approach that combines the matching-pursuit algorithm with a gradient-based optimization method. The accuracy and efficiency of the resulting propagation method are demonstrated as applied to the canonical model systems introduced by Tully for testing simulations of dual curve-crossing nonadiabatic dynamics.

  2. Culture, cognition and behavior in the pursuit of self-esteem

    DEFF Research Database (Denmark)

    Strandell, Jacob

    2016-01-01

    Self-esteem research, arguably the largest field of research in the history of social science, has devoted much of its efforts to the idea that self-esteem causes a broad range of behavioral and social problems, but has failed to produce strong consistent evidence for most claims. However......, this research has conceptual and methodological problems, including a limited understanding of the role of culture, and the assumption that global levels of self-esteem are the main causal mechanism of interest. This paper argues that self-esteem motivated behavior may be better understood as socio......-culturally contextualized pursuits of valued identities, which are difficult to understand without considering their social and cultural conditions. Self-esteem is therefore at the intersection of culture and cognition, and it is argued that an interdisciplinary approach to self-esteem pursuits could be beneficial. A way...

  3. Matching pursuit and source deflation for sparse EEG/MEG dipole moment estimation.

    Science.gov (United States)

    Wu, Shun Chi; Swindlehurst, A Lee

    2013-08-01

    In this paper, we propose novel matching pursuit (MP)-based algorithms for EEG/MEG dipole source localization and parameter estimation for multiple measurement vectors with constant sparsity. The algorithms combine the ideas of MP for sparse signal recovery and source deflation, as employed in estimation via alternating projections. The source-deflated matching pursuit (SDMP) approach mitigates the problem of residual interference inherent in sequential MP-based methods or recursively applied (RAP)-MUSIC. Furthermore, unlike prior methods based on alternating projection, SDMP allows one to efficiently estimate the dipole orientation in addition to its location. Simulations show that the proposed algorithms outperform existing techniques under various conditions, including those with highly correlated sources. Results using real EEG data from auditory experiments are also presented to illustrate the performance of these algorithms.

  4. [Eco-value level classification model of forest ecosystem based on modified projection pursuit technique].

    Science.gov (United States)

    Wu, Chengzhen; Hong, Wei; Hong, Tao

    2006-03-01

    To optimize the projection function and direction of projection pursuit technique, predigest its realization process, and overcome the shortcomings in long time calculation and in the difficulty of optimizing projection direction and computer programming, this paper presented a modified simplex method (MSM), and based on it, brought forward the eco-value level classification model (EVLCM) of forest ecosystem, which could integrate the multidimensional classification index into one-dimensional projection value, with high projection value denoting high ecosystem services value. Examples of forest ecosystem could be reasonably classified by the new model according to their projection value, suggesting that EVLCM driven directly by samples data of forest ecosystem was simple and feasible, applicable, and maneuverable. The calculating time and value of projection function were 34% and 143% of those with the traditional projection pursuit technique, respectively. This model could be applied extensively to classify and estimate all kinds of non-linear and multidimensional data in ecology, biology, and regional sustainable development.

  5. Toward realistic pursuit-evasion using a roadmap-based approach

    KAUST Repository

    Rodriguez, Samuel

    2011-05-01

    In this work, we describe an approach for modeling and simulating group behaviors for pursuit-evasion that uses a graph-based representation of the environment and integrates multi-agent simulation with roadmap-based path planning. Our approach can be applied to more realistic scenarios than are typically studied in most previous work, including agents moving in 3D environments such as terrains, multi-story buildings, and dynamic environments. We also support more realistic three-dimensional visibility computations that allow evading agents to hide in crowds or behind hills. We demonstrate the utility of this approach on mobile robots and in simulation for a variety of scenarios including pursuit-evasion and tag on terrains, in multi-level buildings, and in crowds. © 2011 IEEE.

  6. Workshop on advances in smooth particle hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Wingate, C.A.; Miller, W.A.

    1993-12-31

    This proceedings contains viewgraphs presented at the 1993 workshop held at Los Alamos National Laboratory. Discussed topics include: negative stress, reactive flow calculations, interface problems, boundaries and interfaces, energy conservation in viscous flows, linked penetration calculations, stability and consistency of the SPH method, instabilities, wall heating and conservative smoothing, tensors, tidal disruption of stars, breaking the 10,000,000 particle limit, modelling relativistic collapse, SPH without H, relativistic KSPH avoidance of velocity based kernels, tidal compression and disruption of stars near a supermassive rotation black hole, and finally relativistic SPH viscosity and energy.

  7. Smooth Nanowire/Polymer Composite Transparent Electrodes

    KAUST Repository

    Gaynor, Whitney

    2011-04-29

    Smooth composite transparent electrodes are fabricated via lamination of silver nanowires into the polymer poly-(4,3-ethylene dioxythiophene): poly(styrene-sulfonate) (PEDOT:PSS). The surface roughness is dramatically reduced compared to bare nanowires. High-efficiency P3HT:PCBM organic photovoltaic cells can be fabricated using these composites, reproducing the performance of cells on indium tin oxide (ITO) on glass and improving the performance of cells on ITO on plastic. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. ASIC PROTEINS REGULATE SMOOTH MUSCLE CELL MIGRATION

    OpenAIRE

    Grifoni, Samira C.; Jernigan, Nikki L.; Hamilton, Gina; Drummond, Heather A.

    2007-01-01

    The purpose of the present study was to investigate Acid Sensing Ion Channel (ASIC) protein expression and importance in cellular migration. We recently demonstrated Epithelial Na+ Channel (ENaC) proteins are required for vascular smooth muscle cell (VSMC) migration, however the role of the closely related ASIC proteins has not been addressed. We used RT-PCR and immunolabeling to determine expression of ASIC1, ASIC2, ASIC3 and ASIC4 in A10 cells. We used small interference RNA to silence indi...

  9. On spaces of functions of smoothness zero

    International Nuclear Information System (INIS)

    Besov, Oleg V

    2012-01-01

    The paper is concerned with the new spaces B-bar p,q 0 of functions of smoothness zero defined on the n-dimensional Euclidean space R n or on a subdomain G of R n . These spaces are compared with the spaces B p,q 0 (R n ) and bmo(R n ). The embedding theorems for Sobolev spaces are refined in terms of the space B-bar p,q 0 with the limiting exponent. Bibliography: 8 titles.

  10. Altered medial frontal feedback learning signals in anorexia nervosa

    OpenAIRE

    Bernardoni, Fabio; Geisler, Daniel; King, Joseph A.; Javadi, Amir-Homayoun; Ritschel, Franziska; Murr, Julia; Reiter, Andrea M.F.; Rössner, Veit; Smolka, Michael N.; Kiebel, Stefan; Ehrlich, Stefan

    2017-01-01

    Background\\ud \\ud In their relentless pursuit of thinness, individuals with anorexia nervosa (AN) engage in maladaptive behaviors (restrictive food choices, over-exercising) which may originate in altered decision-making and learning.\\ud \\ud Methods\\ud \\ud In this fMRI study we employed computational modelling to elucidate the neural correlates of feedback learning and value-based decision making in 36 female AN patients and 36 age-matched healthy volunteers (12-24 years). Participants perfor...

  11. Goal pursuit, goal adjustment, and affective well-being following lower limb amputation

    OpenAIRE

    Coffey, Laura; Gallagher, Pamela; Desmond, Deirdre; Ryall, Nicola

    2014-01-01

    Objectives. This study examined the relationships between tenacious goal pursuit (TGP), flexible goal adjustment (FGA), and affective well-being in a sample of individuals with lower limb amputations. Design. Cross-sectional, quantitative. Methods. Ninety-eight patients recently admitted to a primary prosthetic rehabilitation programme completed measures of TGP, FGA, positive affect, and negative affect. Results. Hierarchical regression analyses revealed that TGP and FGA accounted fo...

  12. When hawks attack: animal-borne video studies of goshawk pursuit and prey-evasion strategies

    Science.gov (United States)

    Kane, Suzanne Amador; Fulton, Andrew H.; Rosenthal, Lee J.

    2015-01-01

    Video filmed by a camera mounted on the head of a Northern Goshawk (Accipiter gentilis) was used to study how the raptor used visual guidance to pursue prey and land on perches. A combination of novel image analysis methods and numerical simulations of mathematical pursuit models was used to determine the goshawk's pursuit strategy. The goshawk flew to intercept targets by fixing the prey at a constant visual angle, using classical pursuit for stationary prey, lures or perches, and usually using constant absolute target direction (CATD) for moving prey. Visual fixation was better maintained along the horizontal than vertical direction. In some cases, we observed oscillations in the visual fix on the prey, suggesting that the goshawk used finite-feedback steering. Video filmed from the ground gave similar results. In most cases, it showed goshawks intercepting prey using a trajectory consistent with CATD, then turning rapidly to attack by classical pursuit; in a few cases, it showed them using curving non-CATD trajectories. Analysis of the prey's evasive tactics indicated that only sharp sideways turns caused the goshawk to lose visual fixation on the prey, supporting a sensory basis for the surprising frequency and effectiveness of this tactic found by previous studies. The dynamics of the prey's looming image also suggested that the goshawk used a tau-based interception strategy. We interpret these results in the context of a concise review of pursuit–evasion in biology, and conjecture that some prey deimatic ‘startle’ displays may exploit tau-based interception. PMID:25609783

  13. The Pursuit of a Failed U.S. Drug Policy in Latin America

    Science.gov (United States)

    2015-12-01

    POLICY IN LATIN AMERICA by Daniel R. Hildenbrand December 2015 Thomas C. Bruneau Thesis Co-Advisor: Co-Advisor: Thomas Johnson THIS PAGE...TITLE AND SUBTITLE THE PURSUIT OF A FAILED U.S. DRUG POLICY IN LATIN AMERICA 5. FUNDING NUMBERS 6. AUTHOR(S) Daniel R. Hildenbrand 7. PERFORMING...maximum 200 words) This thesis examines why U.S. counterdrug policy in Latin America focuses primarily on the supply side of the drug trade despite

  14. In-Flight Assessment of a Pursuit Guidance Display Format for Manually Flown Precision Instrument Approaches

    Science.gov (United States)

    Moralez, Ernesto, III; Tucker, George E.; Hindson, William S.; Frost, Chad R.; Hardy, Gordon H.

    2004-01-01

    In-flight evaluations of a pursuit guidance display system for manually flown precision instrument approaches were performed. The guidance system was integrated into the RASCAL JUH-60A Black Hawk helicopter. The applicability of the pursuit guidance disp1aFs to the operation of Runway Independent Aircraft (RIA) is made evident because the displays allow the pilot to fly a complex, multi-segment, descending, decelerating approach trajectory. The complex trajectory chosen for this in-flight assessment began from a downwind abeam position at 110 knots and was hand-flown to a 50 ft decision altitude at 40 knots using a rate-command/attitude-hold plus turn-coordination control system. The elements of the pursuit guidance format displayed on a 10-inch liquid crystal display (LCD) flat panel consisted of a flightpath vector and a "leader" aircraft as the pursuit guidance element. Approach guidance was based primarily on carrier-phase differential Global Positioning System (GPS) navigation, and secondarily on both medium accuracy inertial navigation unit states and air data computer states. Required Navigation Performance (RNP) concepts were applied to the construction of display elements such as lateral/vertical deviation indicators and a tunnel that indicated to the pilot, in real-time, the performance with respect to RNP error bounds. The results of the flight evaluations of the guidance display show that precise path control for operating within tight RNP boundaries (RNP 0.007NM/24ft for initial approach, RNP 0.008NM/19ft for intermediate approach, and RNP 0.002NM/9ft for final approach) is attainable with minimal to moderate pilot workload.

  15. Pursuing the pursuit of happiness: delving into the secret minds of the American founding fathers

    OpenAIRE

    Spier, Fred

    2013-01-01

    Thomas Jefferson's inspiration for including ‘the pursuit of happiness’ in the U.S. Declaration of Independence is usually traced back to the ideas of the English philosophers John Locke and William Wollaston as well as the Swiss philosopher Jean Jacques Burlamaqui. This may well be correct to a considerable extent. In this article, however, based on documentary evidence it is argued that the revolutionary ideas of two radical Enlightenment atheists, Paul-Henri Thiry Baron d'Holbach and Denis...

  16. Utility-value intervention with parents increases students' STEM preparation and career pursuit.

    Science.gov (United States)

    Rozek, Christopher S; Svoboda, Ryan C; Harackiewicz, Judith M; Hulleman, Chris S; Hyde, Janet S

    2017-01-31

    During high school, developing competence in science, technology, engineering, and mathematics (STEM) is critically important as preparation to pursue STEM careers, yet students in the United States lag behind other countries, ranking 35th in mathematics and 27th in science achievement internationally. Given the importance of STEM careers as drivers of modern economies, this deficiency in preparation for STEM careers threatens the United States' continued economic progress. In the present study, we evaluated the long-term effects of a theory-based intervention designed to help parents convey the importance of mathematics and science courses to their high-school-aged children. A prior report on this intervention showed that it promoted STEM course-taking in high school; in the current follow-up study, we found that the intervention improved mathematics and science standardized test scores on a college preparatory examination (ACT) for adolescents by 12 percentile points. Greater high-school STEM preparation (STEM course-taking and ACT scores) was associated with increased STEM career pursuit (i.e., STEM career interest, the number of college STEM courses, and students' attitudes toward STEM) 5 y after the intervention. These results suggest that the intervention can affect STEM career pursuit indirectly by increasing high-school STEM preparation. This finding underscores the importance of targeting high-school STEM preparation to increase STEM career pursuit. Overall, these findings demonstrate that a motivational intervention with parents can have important effects on STEM preparation in high school, as well as downstream effects on STEM career pursuit 5 y later.

  17. Smooth Decomposition of Generalized Fatou Set Explains Smooth Structure in Generalized Mandelbrot Set

    Science.gov (United States)

    Peinke, J.; Parisi, J.; Röhricht, B.; Rössler, O. E.; Metzler, W.

    1988-01-01

    Generalized Mandelbrot sets arise in perturbed (non-analytic) versions of the complex logistic map. Numerically, it contains smooth portions as shown previously. To exclude that this result is specific to particular initial conditions only, the structure of the analogue to the Fatou set is looked at in the region in question. The set of non-divergent points is being "eaten up" by a smooth invading boundary. Therefore, the same type of decomposition applies independent of position in parameter space, in the region in question.

  18. Multi-target consensus circle pursuit for multi-agent systems via a distributed multi-flocking method

    Science.gov (United States)

    Pei, Huiqin; Chen, Shiming; Lai, Qiang

    2016-12-01

    This paper studies the multi-target consensus pursuit problem of multi-agent systems. For solving the problem, a distributed multi-flocking method is designed based on the partial information exchange, which is employed to realise the pursuit of multi-target and the uniform distribution of the number of pursuing agents with the dynamic target. Combining with the proposed circle formation control strategy, agents can adaptively choose the target to form the different circle formation groups accomplishing a multi-target pursuit. The speed state of pursuing agents in each group converges to the same value. A Lyapunov approach is utilised to analyse the stability of multi-agent systems. In addition, a sufficient condition is given for achieving the dynamic target consensus pursuit, and which is then analysed. Finally, simulation results verify the effectiveness of the proposed approaches.

  19. Self-reported goal pursuit and purpose in life among people with dementia.

    Science.gov (United States)

    Mak, Wingyun

    2011-03-01

    Existential aspects of well-being are rarely studied in people with dementia, despite their reported importance. Self-report methods are also rarely used, despite the growing evidence for its use in mild-to-moderate dementia and the lack of concordance between self-reports and proxy reports of well-being. The goal of this study was to examine the relationship between one aspect of well-being, purpose in life, and one of its predictors, goal pursuit, while employing the self-report of individuals with dementia. Questionnaire and experimental methods were used to gauge the relationship between goal pursuit and purpose in life. The experimental portion was structured around creative drawing activities that are often used in adult day service centers. People with mild-to-moderate dementia were able to provide reliable self-report data on their well-being. A strong association between goal pursuit and purpose in life emerged, but dementia severity did not moderate this relationship. People with dementia who engage in goal-directed activity may experience a greater sense of purpose. Results from this study illuminate the experience of psychological well-being in dementia and may inform activity programming for this population.

  20. Close relationships and self-regulation: How relationship satisfaction facilitates momentary goal pursuit.

    Science.gov (United States)

    Hofmann, Wilhelm; Finkel, Eli J; Fitzsimons, Gráinne M

    2015-09-01

    In the new millennium, scholars have built a robust intersection between close-relationships research and self-regulation research. However, virtually no work has investigated how the most basic and broad indicator of relationship quality, relationship satisfaction, affects self-regulation and vice versa. In the present research, we show that higher relationship satisfaction promotes a motivational mind-set that is conducive for effective self-regulation, and thus for goal progress and performance. In Study 1-a large-scale, intensive experience sampling project of 115 couples (total N = 230)-we closely tracked fluctuations in state relationship satisfaction (SRS) and 4 parameters of effective self-regulation according to our conceptual model. Dyadic process analyses showed that individuals experiencing higher SRS than they typically do exhibited higher levels of (a) perceived control, (b) goal focus, (c) perceived partner support, and (d) positive affect during goal pursuit than they typically exhibit. Together, these 4 self-regulation-relevant variables translated into higher rates of daily progress on specific, idiographic goals. In Study 2 (N = 195), we employed a novel experimental manipulation of SRS, replicating the link between SRS and parameters of effective self-regulation. Taken together, these findings suggest that momentary increases in relationship satisfaction may benefit everyday goal pursuit through a combination of cognitive and affective mechanisms, thus further integrating relationship research with social-cognitive research on goal pursuit. (c) 2015 APA, all rights reserved).

  1. Pursuit tracking and higher levels of skill development in the human pilot

    Science.gov (United States)

    Hess, R. A.

    1981-01-01

    A model of the human pilot is offered for pursuit tracking tasks; the model encompasses an existing model for compensatory tracking. The central hypothesis in the development of this model states that those primary structural elements in the compensatory model responsible for the pilot's equalization capabilities remain intact in the pursuit model. In this latter case, effective low-frequency inversion of the controlled-element dynamics occurs by feeding-forward derived input rate through the equalization dynamics, with low-frequency phase droop minimized. The sharp reduction in low-frequency phase lag beyond that associated with the disappearance of phase droop is seen to accompany relatively low-gain feedback of vehicle output. The results of some recent motion cue research are discussed and interpreted in terms of the compensatory-pursuit display dichotomy. Tracking with input preview is discussed in a qualitative way. In terms of the model, preview is shown to demand no fundamental changes in structure or equalization and to allow the pilot to eliminate the effective time delays that accrue in the inversion of the controlled-element dynamics. Precognitive behavior is discussed, and a model that encompasses all the levels of skill development outlined in the successive organizations of perception theory is finally proposed.

  2. Optimizing the Team for Required Power During Track-Cycling Team Pursuit.

    Science.gov (United States)

    Heimans, Levi; Dijkshoorn, Wouter R; Hoozemans, Marco J M; de Koning, Jos J

    2017-11-01

    Since the aim of the men's team pursuit in time-trial track cycling is to accomplish a distance of 4000 m as fast as possible, optimizing aerodynamic drag can contribute to achieving this goal. The aim of this study was to determine the drafting effect in second, third, and fourth position during the team pursuit in track cycling as a function of the team members' individual frontal areas in order to minimize the required power. Eight experienced track cyclists of the Dutch national selection performed 39 trials of 3 km in different teams of 4 cyclists at a constant velocity of 15.75 m/s. Frontal projected areas were determined, and together with field-derived drag coefficients for all 4 positions, the relationships between frontal areas of team members and drag fractions were estimated using generalized estimating equations. The frontal area of both the cyclist directly in front of the drafter and the drafter himself turned out to be significant determinants of the drag fraction at the drafter's position (P team composition. For a team, a maximal difference in team efficiency (1.2%) exists by selecting cyclists in a specific sequence. Estimating required power for a specific team composition gives insight into differences in team efficiency for the team pursuit. Furthermore, required power for individual team members ranges substantially depending on team composition.

  3. A model of the factors affecting international postgraduate students’ pursuit of degrees: A case study

    Directory of Open Access Journals (Sweden)

    Desmond Wesley Govender

    2016-03-01

    Full Text Available The aim of this paper is to present a model of the factors affecting international students’ pursuit of their academic degrees in tertiary institutions. This was achieved by identifying factors that commonly affect international postgraduate students. This was a questionnaire based case study with a sample of 24 post-graduate international students from one university in KwaZulu-Natal. Questionnaires were analysed using SPSS (version 21.0 and WarpPLS (4.0. WarpPLS (4.0 was used to draw up a statistically based model regarding the factors affecting international students in pursuit of their academic degrees. Results from the model show that financial stress, accommodation challenges, cultural shock, loneliness/homesick, communication skills and evaluation of their (previous university experience affect students in their pursuit of their academic degrees in higher education. These findings could be used by students themselves to make them aware of possible challenges that lie ahead as well as by staff in international student offices at higher education institutions.

  4. Airway smooth muscle cell culture: application to studies of airway wall remodelling and phenotype plasticity in asthma.

    Science.gov (United States)

    Hirst, S J

    1996-04-01

    Chronic persistent asthma is characterized by poorly reversible airway obstruction. Histopathological studies of airways removed postmortem from patients with severe asthma reveal marked inflammatory and architectural changes associated with airway wall thickening. Increased airway smooth muscle content, occurring as a result of hyperplastic and/or hypertrophic growth, is believed to be one of the principal contributors to airway wall thickening. Intense interest is building to discover the mechanisms responsible for these long-term structural changes. In vitro cell culture offers a powerful and exacting approach to cellular and molecular studies of the long-term regulation of airway smooth muscle function. This review discusses the methodologies for establishing and maintaining cell cultures of airway smooth muscle. It also describes the characteristics of these cells in culture and addresses the potential importance of phenotype plasticity and its possible relationship to altered smooth muscle function in vivo. Drawing on parallels from vascular studies, this review focuses, in particular, on the synthetic nature of the airway smooth muscle cell, emphasizing its potential to alter the composition of the extracellular matrix environment and orchestrate key events in the process of chronic airway remodelling.

  5. Surface engineering with ion beams: from self-organized nanostructures to ultra-smooth surfaces

    International Nuclear Information System (INIS)

    Frost, F.; Ziberi, B.; Schindler, A.; Rauschenbach, B.

    2008-01-01

    Low-energy ion-beam sputtering, i.e. the removal of atoms from a surface due to the impact of energetic ions or atoms, is an inherent part of numerous surface processing techniques. Besides the actual removal of material, this surface erosion process often results in a pronounced alteration of the surface topography. Under certain conditions, sputtering results in the formation of well-ordered patterns. This self-organized pattern formation is related to a surface instability between curvature-dependent sputtering that roughens the surface and smoothing by different surface relaxation mechanisms. If the evolution of surface topography is dominated by relaxation mechanisms, surface smoothing can occur. In this presentation the current status of self-organized pattern formation and surface smoothing by low-energy ion-beam erosion of Si and Ge is summarized. In detail it will be shown that a multitude of patterns as well as ultra-smooth surfaces can develop, particularly on Si surfaces. Additionally, the most important experimental parameters that control these processes are discussed. Finally, examples are given for the application of low-energy ion beams as a novel approach for passive optical device engineering for many advanced optical applications. (orig.)

  6. Isotropic Growth of Graphene toward Smoothing Stitching.

    Science.gov (United States)

    Zeng, Mengqi; Tan, Lifang; Wang, Lingxiang; Mendes, Rafael G; Qin, Zhihui; Huang, Yaxin; Zhang, Tao; Fang, Liwen; Zhang, Yanfeng; Yue, Shuanglin; Rümmeli, Mark H; Peng, Lianmao; Liu, Zhongfan; Chen, Shengli; Fu, Lei

    2016-07-26

    The quality of graphene grown via chemical vapor deposition still has very great disparity with its theoretical property due to the inevitable formation of grain boundaries. The design of single-crystal substrate with an anisotropic twofold symmetry for the unidirectional alignment of graphene seeds would be a promising way for eliminating the grain boundaries at the wafer scale. However, such a delicate process will be easily terminated by the obstruction of defects or impurities. Here we investigated the isotropic growth behavior of graphene single crystals via melting the growth substrate to obtain an amorphous isotropic surface, which will not offer any specific grain orientation induction or preponderant growth rate toward a certain direction in the graphene growth process. The as-obtained graphene grains are isotropically round with mixed edges that exhibit high activity. The orientation of adjacent grains can be easily self-adjusted to smoothly match each other over a liquid catalyst with facile atom delocalization due to the low rotation steric hindrance of the isotropic grains, thus achieving the smoothing stitching of the adjacent graphene. Therefore, the adverse effects of grain boundaries will be eliminated and the excellent transport performance of graphene will be more guaranteed. What is more, such an isotropic growth mode can be extended to other types of layered nanomaterials such as hexagonal boron nitride and transition metal chalcogenides for obtaining large-size intrinsic film with low defect.

  7. Coupling of smooth particle hydrodynamics with PRONTO

    Energy Technology Data Exchange (ETDEWEB)

    Attaway, S.W.; Heinstein, M.W.; Mello, F.J.; Swegle, J.W.

    1993-08-01

    A gridless numerical technique called smooth particle hydrodynamics (SPH) has been coupled to the transient dynamics finite element code, PRONTO. In this paper, a new weighted residual derivation for the SPH method will be presented, and the methods used to embed SPH within PRONTO will be outlined. Example SPH-PRONTO calculations will also be presented. One major difficulty associated with the Lagrangian finite element method is modeling materials with no shear strength; for example, gases, fluids and explosive bi-products. Typically these materials can be modeled for only a short time with a Lagrangian finite element code. Large distortions cause tangling of the mesh, which will eventually lead to numerical difficulties such as negative element area or ``bow tie`` elements. Remeshing will allow the problem to continue for a short while, but the large distortions can prevent a complete analysis. Smooth particle hydrodynamics is a gridless Lagrangian technique. Requiring no mesh, SPH has the potential to model material fracture, large shear flows, and penetration. SPH computes the strain rate and the stress divergence based on the nearest neighbors of a particle, which are determined using an efficient particle sorting technique. Embedding the SPH method within PRONTO allows part of the problem to be modeled with quadrilateral finite elements while other parts are modeled with the gridless SPH method. SPH elements are coupled to the quadrilateral elements through a contact like algorithm.

  8. Smooth manifold structure for extreme channels

    Science.gov (United States)

    Iten, Raban; Colbeck, Roger

    2018-01-01

    A quantum channel from a system A of dimension dA to a system B of dimension dB is a completely positive trace-preserving map from complex dA × dA to dB × dB matrices, and the set of all such maps with Kraus rank r has the structure of a smooth manifold. We describe this set in two ways. First, as a quotient space of (a subset of) the rdB × dA dimensional Stiefel manifold. Second, as the set of all Choi-states of a fixed rank r. These two descriptions are topologically equivalent. This allows us to show that the set of all Choi-states corresponding to extreme channels from system A to system B of a fixed Kraus rank r is a smooth submanifold of dimension 2 r dAdB-dA2-r2 of the set of all Choi-states of rank r. As an application, we derive a lower bound on the number of parameters required for a quantum circuit topology to be able to approximate all extreme channels from A to B arbitrarily well.

  9. Analytic functions smooth up to the boundary

    CERN Document Server

    1988-01-01

    This research monograph concerns the Nevanlinna factorization of analytic functions smooth, in a sense, up to the boundary. The peculiar properties of such a factorization are investigated for the most common classes of Lipschitz-like analytic functions. The book sets out to create a satisfactory factorization theory as exists for Hardy classes. The reader will find, among other things, the theorem on smoothness for the outer part of a function, the generalization of the theorem of V.P. Havin and F.A. Shamoyan also known in the mathematical lore as the unpublished Carleson-Jacobs theorem, the complete description of the zero-set of analytic functions continuous up to the boundary, generalizing the classical Carleson-Beurling theorem, and the structure of closed ideals in the new wide range of Banach algebras of analytic functions. The first three chapters assume the reader has taken a standard course on one complex variable; the fourth chapter requires supplementary papers cited there. The monograph addresses...

  10. Snap evaporation of droplets on smooth topographies.

    Science.gov (United States)

    Wells, Gary G; Ruiz-Gutiérrez, Élfego; Le Lirzin, Youen; Nourry, Anthony; Orme, Bethany V; Pradas, Marc; Ledesma-Aguilar, Rodrigo

    2018-04-11

    Droplet evaporation on solid surfaces is important in many applications including printing, micro-patterning and cooling. While seemingly simple, the configuration of evaporating droplets on solids is difficult to predict and control. This is because evaporation typically proceeds as a "stick-slip" sequence-a combination of pinning and de-pinning events dominated by static friction or "pinning", caused by microscopic surface roughness. Here we show how smooth, pinning-free, solid surfaces of non-planar topography promote a different process called snap evaporation. During snap evaporation a droplet follows a reproducible sequence of configurations, consisting of a quasi-static phase-change controlled by mass diffusion interrupted by out-of-equilibrium snaps. Snaps are triggered by bifurcations of the equilibrium droplet shape mediated by the underlying non-planar solid. Because the evolution of droplets during snap evaporation is controlled by a smooth topography, and not by surface roughness, our ideas can inspire programmable surfaces that manage liquids in heat- and mass-transfer applications.

  11. Reflex tracheal smooth muscle contraction and bronchial vasodilation evoked by airway cooling in dogs.

    Science.gov (United States)

    Pisarri, T E; Giesbrecht, G G

    1997-05-01

    Cooling intrathoracic airways by filling the pulmonary circulation with cold blood alters pulmonary mechanoreceptor discharge. To determine whether this initiates reflex changes that could contribute to airway obstruction, we measured changes in tracheal smooth muscle tension and bronchial arterial flow evoked by cooling. In nine chloralose-anesthetized open-chest dogs, the right pulmonary artery was cannulated and perfused; the left lung, ventilated separately, provided gas exchange. With the right lung phasically ventilated, filling the right pulmonary circulation with 5 degrees C blood increased smooth muscle tension in an innervated upper tracheal segment by 23 +/- 6 (SE) g from a baseline of 75 g. Contraction began within 10 s of injection and was maximal at approximately 30s. The response was abolished by cervical vagotomy. Bronchial arterial flow increased from 8 +/- 1 to 13 +/- 2 ml/min, with little effect on arterial blood pressure. The time course was similar to that of the tracheal response. This response was greatly attenuated after cervical vagotomy. Blood at 20 degrees C also increased tracheal smooth muscle tension and bronchial flow, whereas 37 degrees C blood had little effect. The results suggested that alteration of airway mechanoreceptor discharge by cooling can initiate reflexes that contribute to airway obstruction.

  12. Potentiation of contraction of rabbit airway smooth muscle by some cyclooxygenase products.

    Science.gov (United States)

    Armour, C L; Johnson, P R; Black, J L

    1988-06-01

    An alteration in smooth muscle sensitivity may be one of the mechanisms of the airway hyperresponsiveness observed in asthma. Indomethacin inhibits experimentally induced airway hyperresponsiveness. We thus examined the effects of the cyclooxygenase products PGD2, PGF2 alpha and a thromboxane A2 analogue U46619 on contractile responses of rabbit airway smooth muscle to histamine, carbachol and electrical field stimulation (EFS). PGD2 did not potentiate any contractile responses. When PGF2 alpha (1 microM) was administered 30 min before cumulative concentration-response curves to histamine and carbachol, no potentiation was observed. However, PGF2 alpha (1 microM) added immediately before EFS and bolus doses of histamine potentiated the contractile responses. U46619 increased the cumulative concentration-responses to both histamine and carbachol. The fact that we could alter smooth muscle sensitivity in vitro with PGF2 alpha and a thromboxane analogue suggests that these mediators may be involved in the airway hyperresponsiveness observed in asthma.

  13. An analysis of smoothed particle hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Swegle, J.W.; Attaway, S.W.; Heinstein, M.W.; Mello, F.J. [Sandia National Labs., Albuquerque, NM (United States); Hicks, D.L. [Michigan Technological Univ., Houghton, MI (United States)

    1994-03-01

    SPH (Smoothed Particle Hydrodynamics) is a gridless Lagrangian technique which is appealing as a possible alternative to numerical techniques currently used to analyze high deformation impulsive loading events. In the present study, the SPH algorithm has been subjected to detailed testing and analysis to determine its applicability in the field of solid dynamics. An important result of the work is a rigorous von Neumann stability analysis which provides a simple criterion for the stability or instability of the method in terms of the stress state and the second derivative of the kernel function. Instability, which typically occurs only for solids in tension, results not from the numerical time integration algorithm, but because the SPH algorithm creates an effective stress with a negative modulus. The analysis provides insight into possible methods for removing the instability. Also, SPH has been coupled into the transient dynamics finite element code PRONTO, and a weighted residual derivation of the SPH equations has been obtained.

  14. Smoothed Particle Hydrodynamics Coupled with Radiation Transfer

    Science.gov (United States)

    Susa, Hajime

    2006-04-01

    We have constructed a brand-new radiation hydrodynamics solver based upon Smoothed Particle Hydrodynamics, which works on a parallel computer system. The code is designed to investigate the formation and evolution of first-generation objects at z ≳ 10, where the radiative feedback from various sources plays important roles. The code can compute the fraction of chemical species e, H+, H, H-, H2, and H+2 by by fully implicit time integration. It also can deal with multiple sources of ionizing radiation, as well as radiation at Lyman-Werner band. We compare the results for a few test calculations with the results of one-dimensional simulations, in which we find good agreements with each other. We also evaluate the speedup by parallelization, which is found to be almost ideal, as long as the number of sources is comparable to the number of processors.

  15. Smooth Teeth: Why Multipoles Are Perfect Gears

    Science.gov (United States)

    Schönke, Johannes

    2015-12-01

    A type of gear is proposed based on the interaction of individual multipoles. The underlying principle relies on previously unknown continuous degenerate ground states for pairs of interacting multipoles which are free to rotate around specific axes. These special rotation axes, in turn, form a one-parameter family of possible configurations. This allows for the construction of magnetic bevel gears with any desired inclination angle between the in- and output axes. Further, the design of gear systems with more than two multipoles is possible and facilitates tailored applications. Ultimately, an analogy between multipoles and mechanical gears is revealed. In contrast to the mechanical case, the multipole "teeth" mesh smoothly. As an illustrative application, the example of a quadrupole-dipole interaction is then used to construct a 1 ∶2 gear ratio.

  16. Diffusion tensor smoothing through weighted Karcher means

    Science.gov (United States)

    Carmichael, Owen; Chen, Jun; Paul, Debashis; Peng, Jie

    2014-01-01

    Diffusion tensor magnetic resonance imaging (MRI) quantifies the spatial distribution of water Diffusion at each voxel on a regular grid of locations in a biological specimen by Diffusion tensors– 3 × 3 positive definite matrices. Removal of noise from DTI is an important problem due to the high scientific relevance of DTI and relatively low signal to noise ratio it provides. Leading approaches to this problem amount to estimation of weighted Karcher means of Diffusion tensors within spatial neighborhoods, under various metrics imposed on the space of tensors. However, it is unclear how the behavior of these estimators varies with the magnitude of DTI sensor noise (the noise resulting from the thermal e!ects of MRI scanning) as well as the geometric structure of the underlying Diffusion tensor neighborhoods. In this paper, we combine theoretical analysis, empirical analysis of simulated DTI data, and empirical analysis of real DTI scans to compare the noise removal performance of three kernel-based DTI smoothers that are based on Euclidean, log-Euclidean, and affine-invariant metrics. The results suggest, contrary to conventional wisdom, that imposing a simplistic Euclidean metric may in fact provide comparable or superior noise removal, especially in relatively unstructured regions and/or in the presence of moderate to high levels of sensor noise. On the contrary, log-Euclidean and affine-invariant metrics may lead to better noise removal in highly structured anatomical regions, especially when the sensor noise is of low magnitude. These findings emphasize the importance of considering the interplay of sensor noise magnitude and tensor field geometric structure when assessing Diffusion tensor smoothing options. They also point to the necessity for continued development of smoothing methods that perform well across a large range of scenarios. PMID:25419264

  17. Impact of spectral smoothing on gamma radiation portal alarm probabilities

    International Nuclear Information System (INIS)

    Burr, T.; Hamada, M.; Hengartner, N.

    2011-01-01

    Gamma detector counts are included in radiation portal monitors (RPM) to screen for illicit nuclear material. Gamma counts are sometimes smoothed to reduce variance in the estimated underlying true mean count rate, which is the 'signal' in our context. Smoothing reduces total error variance in the estimated signal if the bias that smoothing introduces is more than offset by the variance reduction. An empirical RPM study for vehicle screening applications is presented for unsmoothed and smoothed gamma counts in low-resolution plastic scintillator detectors and in medium-resolution NaI detectors. - Highlights: → We evaluate options for smoothing counts from gamma detectors deployed for portal monitoring. → A new multiplicative bias correction (MBC) is shown to reduce bias in peak and valley regions. → Performance is measured using mean squared error and detection probabilities for sources. → Smoothing with the MBC improves detection probabilities and the mean squared error.

  18. Smoothing the wavelet periodogram using the Haar-Fisz transform

    OpenAIRE

    Piotr Fryzlewicz; Guy P. Nason

    2004-01-01

    The wavelet periodogram is hard to smooth because of the low signal-to-noise ratio and non-stationary covariance structure. This article introduces a method for smoothing a local wavelet periodogram by applying a Haar-Fisz transform which approximately Gaussianizes and approximately stabilizes the variance of the periodogram. Consequently, smoothing the transformed periodogram can take advantage of the wide variety of existing techniques suitable for homogeneous Gaussian data. This article de...

  19. A sharp recovery condition for block sparse signals by block orthogonal multi-matching pursuit

    OpenAIRE

    Chen, Wengu; Ge, Huanmin

    2016-01-01

    We consider the block orthogonal multi-matching pursuit (BOMMP) algorithm for the recovery of block sparse signals. A sharp bound is obtained for the exact reconstruction of block $K$-sparse signals via the BOMMP algorithm in the noiseless case, based on the block restricted isometry constant (block-RIC). Moreover, we show that the sharp bound combining with an extra condition on the minimum $\\ell_2$ norm of nonzero blocks of block $K-$sparse signals is sufficient to recover the true support ...

  20. Nostalgia motivates pursuit of important goals by increasing meaning in life

    DEFF Research Database (Denmark)

    Sedikides, Constantine; Cheung, Wing-Yee; Wildschut, Tim

    2018-01-01

    This research focused on existential and motivational implications of the emotion of nostalgia. Nostalgia (relative to control) increased meaning in life, which, in turn, galvanised intentions to pursue one's most important goal (Experiment 1) and to pursue one's most important, but not least...... important, goal (Experiment 2). The basic pattern held in two cultures (British and Danish) independently of positive affect. This is the first evidence that nostalgia has specific motivational consequences (i.e., pursuit of more, but not less, important goals) and transmits these consequences via meaning...

  1. Goodness-of-Fit Tests For Elliptical and Independent Copulas through Projection Pursuit

    Directory of Open Access Journals (Sweden)

    Jacques Touboul

    2011-04-01

    Full Text Available Two goodness-of-fit tests for copulas are being investigated. The first one deals with the case of elliptical copulas and the second one deals with independent copulas. These tests result from the expansion of the projection pursuit methodology that we will introduce in the present article. This method enables us to determine on which axis system these copulas lie as well as the exact value of these very copulas in the basis formed by the axes previously determined irrespective of their value in their canonical basis. Simulations are also presented as well as an application to real datasets.

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

    Science.gov (United States)

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

    2012-03-01

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

  3. A Smoothed Particle Hydrodynamics approach for poroelasticity

    Science.gov (United States)

    Osorno, Maria; Steeb, Holger

    2016-04-01

    Within the framework of the SHynergie project we look to investigate hydraulic fracturing and crack evolving in poroelastic media. We model biphasic media assuming incompressible solid grain and incompressible pore liquid. Modeling evolving fractures and fracture networks in elastic and poroelastic media by mesh-based numerical approaches, like X-FEM, is especially in 3-dim a challenging task. Therefore, we propose a meshless particle method for fractured media based on the Smoothed Particle Hydrodynamics (SPH) approach. SPH is a meshless Lagrangian method highly suitable for the simulation of large deformations including free surfaces and/or interfaces. Within the SPH method, the computational domain is discretized with particles, avoiding the computational expenses of meshing. Our SPH solution is implemented in a parallel computational framework, which allows to simulate large domains more representative of the scale of our study cases. Our implementation is carefully validated against classical mesh-based approaches and compared with classical solutions for consolidation problems. Furthermore, we discuss fracture initiation and propagation in poroelastic rocks at the reservoir scale.

  4. ASIC proteins regulate smooth muscle cell migration.

    Science.gov (United States)

    Grifoni, Samira C; Jernigan, Nikki L; Hamilton, Gina; Drummond, Heather A

    2008-03-01

    The purpose of the present study was to investigate Acid Sensing Ion Channel (ASIC) protein expression and importance in cellular migration. We recently demonstrated that Epithelial Na(+)Channel (ENaC) proteins are required for vascular smooth muscle cell (VSMC) migration; however, the role of the closely related ASIC proteins has not been addressed. We used RT-PCR and immunolabeling to determine expression of ASIC1, ASIC2, ASIC3 and ASIC4 in A10 cells. We used small interference RNA to silence individual ASIC expression and determine the importance of ASIC proteins in wound healing and chemotaxis (PDGF-bb)-initiated migration. We found ASIC1, ASIC2, and ASIC3, but not ASIC4, expression in A10 cells. ASIC1, ASIC2, and ASIC3 siRNA molecules significantly suppressed expression of their respective proteins compared to non-targeting siRNA (RISC) transfected controls by 63%, 44%, and 55%, respectively. Wound healing was inhibited by 10, 20, and 26% compared to RISC controls following suppression of ASIC1, ASIC2, and ASIC3, respectively. Chemotactic migration was inhibited by 30% and 45%, respectively, following suppression of ASIC1 and ASIC3. ASIC2 suppression produced a small, but significant, increase in chemotactic migration (4%). Our data indicate that ASIC expression is required for normal migration and may suggest a novel role for ASIC proteins in cellular migration.

  5. Smooth cubic commensurate oxides on gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Paisley, Elizabeth A.; Gaddy, Benjamin E.; LeBeau, James M.; Shelton, Christopher T.; Losego, Mark D.; Mita, Seiji; Collazo, Ramón; Sitar, Zlatko; Irving, Douglas L.; Maria, Jon-Paul, E-mail: jpmaria@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Biegalski, Michael D.; Christen, Hans M. [Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-02-14

    Smooth, commensurate alloys of 〈111〉-oriented Mg{sub 0.52}Ca{sub 0.48}O (MCO) thin films are demonstrated on Ga-polar, c+ [0001]-oriented GaN by surfactant-assisted molecular beam epitaxy and pulsed laser deposition. These are unique examples of coherent cubic oxide|nitride interfaces with structural and morphological perfection. Metal-insulator-semiconductor capacitor structures were fabricated on n-type GaN. A comparison of leakage current density for conventional and surfactant-assisted growth reveals a nearly 100× reduction in leakage current density for the surfactant-assisted samples. HAADF-STEM images of the MCO|GaN interface show commensurate alignment of atomic planes with minimal defects due to lattice mismatch. STEM and DFT calculations show that GaN c/2 steps create incoherent boundaries in MCO over layers which manifest as two in-plane rotations and determine consequently the density of structural defects in otherwise coherent MCO. This new understanding of interfacial steps between HCP and FCC crystals identifies the steps needed to create globally defect-free heterostructures.

  6. Device Simulation using Symmetric Smoothed Particle Hydrodynamics

    Science.gov (United States)

    Kitayama, K.; Toogoshi, M.; Zempo, Y.

    2017-10-01

    We have applied symmetric smoothed particle hydrodynamics (SSPH) to electronic structure calculations for high electron mobility transistors (HEMTs). In layered structures such as field effect transistors (FETs), and especially HEMTs, the current density is mainly dependent on the electron mobility and the electronic field near the gate, where both can be taken to be constant. The relation between the channel current and the applied gate voltage can be obtained by a one-dimensional calculation. Then, it is easy to apply SSPH to evaluate the simple quantum properties of a device. We mainly focus on the I-V characteristics, which are typical device features. The electronic structure of a HEMT was calculated using both SSPH and finite-difference (FD) methods. The results from SSPH calculations are in good agreement with those from the FD method, and the accuracy of SSPH is similar to that of FD. In a simple example, where three particles are employed in the SSPH domain, we show there is an equivalence to the three-point method in FD.

  7. An implicit Smooth Particle Hydrodynamic code

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, Charles E. [Univ. of New Mexico, Albuquerque, NM (United States)

    2000-05-01

    An implicit version of the Smooth Particle Hydrodynamic (SPH) code SPHINX has been written and is working. In conjunction with the SPHINX code the new implicit code models fluids and solids under a wide range of conditions. SPH codes are Lagrangian, meshless and use particles to model the fluids and solids. The implicit code makes use of the Krylov iterative techniques for solving large linear-systems and a Newton-Raphson method for non-linear corrections. It uses numerical derivatives to construct the Jacobian matrix. It uses sparse techniques to save on memory storage and to reduce the amount of computation. It is believed that this is the first implicit SPH code to use Newton-Krylov techniques, and is also the first implicit SPH code to model solids. A description of SPH and the techniques used in the implicit code are presented. Then, the results of a number of tests cases are discussed, which include a shock tube problem, a Rayleigh-Taylor problem, a breaking dam problem, and a single jet of gas problem. The results are shown to be in very good agreement with analytic solutions, experimental results, and the explicit SPHINX code. In the case of the single jet of gas case it has been demonstrated that the implicit code can do a problem in much shorter time than the explicit code. The problem was, however, very unphysical, but it does demonstrate the potential of the implicit code. It is a first step toward a useful implicit SPH code.

  8. Bandwidth selection in smoothing functions | Kibua | East African ...

    African Journals Online (AJOL)

    ... inexpensive and, hence, worth adopting. We argue that the bandwidth parameter is determined by two factors: the kernel function and the length of the smoothing region. We give an illustrative example of its application using real data. Keywords: Kernel, Smoothing functions, Bandwidth > East African Journal of Statistics ...

  9. Classification of smooth structures on a homotopy complex ...

    Indian Academy of Sciences (India)

    We classify, up to diffeomorphism, all closed smooth manifolds homeomorphic to the complex projective n -space C P n , where n = 3 and 4. Let M 2 n be a closed smooth 2 n -manifold homotopy equivalent to C P n . We show that, up to diffeomorphism, M 6 has a unique differentiable structure and M 8 has at most two ...

  10. Mechanism of kolaviron-induced relaxation of rabbit aortic smooth ...

    African Journals Online (AJOL)

    There is a considerable evidence linking kolaviron (KV), a biflavanoid-complex of Garcinia kola Heckel seed (gKola) to smooth muscle relaxation. The present study was designed to characterize the mechanism of kolaviron-induced relaxation on contractile responses in ring preparations of vascular smooth muscle (VSM) of ...

  11. Data-driven smooth tests when the hypothesis Is composite

    NARCIS (Netherlands)

    Kallenberg, W.C.M.; Ledwina, Teresa

    1997-01-01

    In recent years several authors have recommended smooth tests for testing goodness of fit. However, the number of components in the smooth test statistic should be chosen well; otherwise, considerable loss of power may occur. Schwarz's selection rule provides one such good choice. Earlier results on

  12. On the extension problem between separable smooth Banach ...

    African Journals Online (AJOL)

    In this paper, we study the extension of isometric operators between unit spheres of separable smooth Banach spaces with the Radon-Nikodym property (RNP). We show that if there is a surjective isometric operator between unit spheres of separable smooth Banach spaces with RNP, then there exists a codimension one ...

  13. Acetylcholine : a novel regulator of airway smooth muscle remodelling?

    NARCIS (Netherlands)

    Gosens, R; Zaagsma, J; Bromhaar, MG; Nelemans, A; Meurs, H

    2004-01-01

    Increased airway smooth muscle mass is a pathological feature that asthma and chronic obstructive pulmonary disease (COPD) have in common. This increase has gained renewed interest in view of recent developments showing that airway smooth muscle, instead of solely being a contractile partner, is

  14. Classification of smooth structures on a homotopy complex ...

    Indian Academy of Sciences (India)

    Abstract. We classify, up to diffeomorphism, all closed smooth manifolds homeo- morphic to the complex projective n-space CPn, where n = 3 and 4. Let M2n be a closed smooth 2n-manifold homotopy equivalent to CPn. We show that, up to diffeo- morphism, M6 has a unique differentiable structure and M8 has at most two ...

  15. Three-phase electric drive with modified electronic smoothing inductor

    DEFF Research Database (Denmark)

    Singh, Yash Veer; Rasmussen, Peter Omand; Andersen, Torben Ole

    2010-01-01

    This paper presents a three-phase electric drive with a modified electronic smoothing inductor (MESI) having reduced size of passive components. The classical electronic smoothing inductor (ESI) is able to control a diode bridge output current and also reduce not only mains current harmonics...

  16. Some asymptotic theory for variance function smoothing | Kibua ...

    African Journals Online (AJOL)

    Simple selection of the smoothing parameter is suggested. Both homoscedastic and heteroscedastic regression models are considered. Keywords: Asymptotic, Smoothing, Kernel, Bandwidth, Bias, Variance, Mean squared error, Homoscedastic, Heteroscedastic. > East African Journal of Statistics Vol. 1 (1) 2005: pp. 9-22 ...

  17. Genetic Programming with Smooth Operators for Arithmetic Expressions

    DEFF Research Database (Denmark)

    Ursem, Rasmus Kjær; Krink, Thiemo

    2002-01-01

    This paper introduces the smooth operators for arithmetic expressions as an approach to smoothening the search space in Genetic Programming (GP). Smooth operator GP interpolates between arithmetic operators such as * and /, thereby allowing a gradual adaptation to the problem. The suggested appro...

  18. Smooth surfaces from bilinear patches: Discrete affine minimal surfaces

    KAUST Repository

    Käferböck, Florian

    2013-06-01

    Motivated by applications in freeform architecture, we study surfaces which are composed of smoothly joined bilinear patches. These surfaces turn out to be discrete versions of negatively curved affine minimal surfaces and share many properties with their classical smooth counterparts. We present computational design approaches and study special cases which should be interesting for the architectural application. 2013 Elsevier B.V.

  19. Regeneration and Maintenance of Intestinal Smooth Muscle Phenotypes

    Science.gov (United States)

    Walthers, Christopher M.

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

  20. Time-Frequency Data Reduction for Event Related Potentials: Combining Principal Component Analysis and Matching Pursuit.

    Science.gov (United States)

    Aviyente, Selin; Bernat, Edward M; Malone, Stephen M; Iacono, William G

    2010-01-01

    Joint time-frequency representations offer a rich representation of event related potentials (ERPs) that cannot be obtained through individual time or frequency domain analysis. This representation, however, comes at the expense of increased data volume and the difficulty of interpreting the resulting representations. Therefore, methods that can reduce the large amount of time-frequency data to experimentally relevant components are essential. In this paper, we present a method that reduces the large volume of ERP time-frequency data into a few significant time-frequency parameters. The proposed method is based on applying the widely-used matching pursuit (MP) approach, with a Gabor dictionary, to principal components extracted from the time-frequency domain. The proposed PCA-Gabor decomposition is compared with other time-frequency data reduction methods such as the time-frequency PCA approach alone and standard matching pursuit methods using a Gabor dictionary for both simulated and biological data. The results show that the proposed PCA-Gabor approach performs better than either the PCA alone or the standard MP data reduction methods, by using the smallest amount of ERP data variance to produce the strongest statistical separation between experimental conditions.

  1. Home and Motivational Factors Related to Science-Career Pursuit: Gender differences and gender similarities

    Science.gov (United States)

    Shin, Jongho; Lee, Hyunjoo; McCarthy-Donovan, Alexander; Hwang, Hyeyoung; Yim, Sonyoung; Seo, EunJin

    2015-06-01

    The purpose of the study was to examine whether gender differences exist in the mean levels of and relations between adolescents' home environments (parents' view of science, socio-economic status (SES)), motivations (intrinsic and instrumental motivations, self-beliefs), and pursuit of science careers. For the purpose, the Programmed for International Student Assessment 2006 data of Korean 15-year-old students were analysed. The results of the study showed that girls had lower levels of science intrinsic and instrumental motivations, self-beliefs, and science-career pursuit (SCP) as well as their parents' values in science less than boys. Gender similarities, rather than gender differences, existed in patterns of causal relationship among home environments, motivations, and SCP. The results showed positive effects for parents' higher value in science and SES on motivations, SCP, and for intrinsic and instrumental motivations on SCP for girls and boys. These results provide implications for educational interventions to decrease gender differences in science motivations and SCP, and to decrease adolescents' gender stereotypes.

  2. Impaired motor memory for a pursuit rotor task following Stage 2 sleep loss in college students.

    Science.gov (United States)

    Smith; MacNeill

    1994-12-01

    It has recently been reported that selective REM sleep deprivation (REMD) in college students results in memory impairment of the application of a set of rules in a logic task, but not recall of a paired associate task. The present experiments were designed to examine the effects of Total Sleep Deprivation (TSD) and (REMD) following acquisition of a pure motor task, the pursuit rotor. In Experiment 1, subjects (N = 90) were exposed to TSD for one of several nights following training. Results showed that TSD on the same night as training resulted in poorer performance on retest one week later. In Experiment 2, subjects (N = 42) were exposed to various kinds of sleep deprivation on the night of task acquisition. One group was subjected to REMD. Other groups included a non-REM awakening control group (NREMA), a TSD group, a normally rested Control group and a group allowed the first 4 h of sleep in the night before being subjected to TSD (LH - TSD) for the rest of the night. Results showed the REMD and Control groups to have excellent memory for this task while the TSD and LH - TSD subjects had significantly poorer memory for the task. The NREMA group showed a slight, but not significant deficit. It was concluded that Stage 2 sleep, rather than REM sleep was the important stage of sleep for efficient memory processing of the pursuit rotor task.

  3. Culture shapes whether the pursuit of happiness predicts higher or lower well-being.

    Science.gov (United States)

    Ford, Brett Q; Dmitrieva, Julia O; Heller, Daniel; Chentsova-Dutton, Yulia; Grossmann, Igor; Tamir, Maya; Uchida, Yukiko; Koopmann-Holm, Birgit; Floerke, Victoria A; Uhrig, Meike; Bokhan, Tatiana; Mauss, Iris B

    2015-12-01

    Pursuing happiness can paradoxically impair well-being. Here, the authors propose the potential downsides to pursuing happiness may be specific to individualistic cultures. In collectivistic (vs. individualistic) cultures, pursuing happiness may be more successful because happiness is viewed--and thus pursued--in relatively socially engaged ways. In 4 geographical regions that vary in level of collectivism (United States, Germany, Russia, East Asia), we assessed participants' well-being, motivation to pursue happiness, and to what extent they pursued happiness in socially engaged ways. Motivation to pursue happiness predicted lower well-being in the United States, did not predict well-being in Germany, and predicted higher well-being in Russia and in East Asia. These cultural differences in the link between motivation to pursue happiness and well-being were explained by cultural differences in the socially engaged pursuit of happiness. These findings suggest that culture shapes whether the pursuit of happiness is linked with better or worse well-being, perhaps via how people pursue happiness. (c) 2015 APA, all rights reserved).

  4. Competence over Communion: Implicit Evaluations of Personality Traits During Goal Pursuit

    Directory of Open Access Journals (Sweden)

    Roczniewska Marta

    2014-12-01

    Full Text Available Research shows that goal-relevant objects are rated positively, which results from their functionality towards the aim. In previous studies these objects were always external to the agent. However, relevant knowledge of self is also potentially accessible during goal pursuit, as self-esteem is an indicator of aim’s feasibility. In two experimental studies we tested whether goal activation affects temporal changes in automatic evaluations of personality traits related to the dimensions of agency and communion. We administered affect misattribution procedure where participants rated neutral Chinese hexagrams proceeded by words describing traits (75 ms masked presentation. The list of words comprised agentic (e.g. agile and communal (e.g. trustworthy traits. The rating took place twice - before and after introducing a manual task. In the first study, goal activation led to slightly more positive implicit evaluations of agentic and more negative evaluation of communal traits, which is consistent with empirical data on self-perception depending on agentic knowledge rather than communal one. In the second study we showed that goal activation led to changes only for promotion-, but not prevention-oriented individuals, which is explained by motivation strength. The results indicate that valuation of traits changes temporarily along with goal pursuit.

  5. Multi-stage approach for structural damage detection problem using basis pursuit and particle swarm optimization

    Science.gov (United States)

    Gerist, Saleheh; Maheri, Mahmoud R.

    2016-12-01

    In order to solve structural damage detection problem, a multi-stage method using particle swarm optimization is presented. First, a new spars recovery method, named Basis Pursuit (BP), is utilized to preliminarily identify structural damage locations. The BP method solves a system of equations which relates the damage parameters to the structural modal responses using the sensitivity matrix. Then, the results of this stage are subsequently enhanced to the exact damage locations and extents using the PSO search engine. Finally, the search space is reduced by elimination of some low damage variables using micro search (MS) operator embedded in the PSO algorithm. To overcome the noise present in structural responses, a method known as Basis Pursuit De-Noising (BPDN) is also used. The efficiency of the proposed method is investigated by three numerical examples: a cantilever beam, a plane truss and a portal plane frame. The frequency response is used to detect damage in the examples. The simulation results demonstrate the accuracy and efficiency of the proposed method in detecting multiple damage cases and exhibit its robustness regarding noise and its advantages compared to other reported solution algorithms.

  6. Time-Frequency Data Reduction for Event Related Potentials: Combining Principal Component Analysis and Matching Pursuit

    Directory of Open Access Journals (Sweden)

    Selin Aviyente

    2010-01-01

    Full Text Available Joint time-frequency representations offer a rich representation of event related potentials (ERPs that cannot be obtained through individual time or frequency domain analysis. This representation, however, comes at the expense of increased data volume and the difficulty of interpreting the resulting representations. Therefore, methods that can reduce the large amount of time-frequency data to experimentally relevant components are essential. In this paper, we present a method that reduces the large volume of ERP time-frequency data into a few significant time-frequency parameters. The proposed method is based on applying the widely used matching pursuit (MP approach, with a Gabor dictionary, to principal components extracted from the time-frequency domain. The proposed PCA-Gabor decomposition is compared with other time-frequency data reduction methods such as the time-frequency PCA approach alone and standard matching pursuit methods using a Gabor dictionary for both simulated and biological data. The results show that the proposed PCA-Gabor approach performs better than either the PCA alone or the standard MP data reduction methods, by using the smallest amount of ERP data variance to produce the strongest statistical separation between experimental conditions.

  7. Regularity and Matching Pursuit feature extraction for the detection of epileptic seizures.

    Science.gov (United States)

    Z-Flores, Emigdio; Trujillo, Leonardo; Sotelo, Arturo; Legrand, Pierrick; Coria, Luis N

    2016-06-15

    The neurological disorder known as epilepsy is characterized by involuntary recurrent seizures that diminish a patient's quality of life. Automatic seizure detection can help improve a patient's interaction with her/his environment, and while many approaches have been proposed the problem is still not trivially solved. In this work, we present a novel methodology for feature extraction on EEG signals that allows us to perform a highly accurate classification of epileptic states. Specifically, Hölderian regularity and the Matching Pursuit algorithm are used as the main feature extraction techniques, and are combined with basic statistical features to construct the final feature sets. These sets are then delivered to a Random Forests classification algorithm to differentiate between epileptic and non-epileptic readings. Several versions of the basic problem are tested and statistically validated producing perfect accuracy in most problems and 97.6% accuracy on the most difficult case. A comparison with recent literature, using a well known database, reveals that our proposal achieves state-of-the-art performance. The experimental results show that epileptic states can be accurately detected by combining features extracted through regularity analysis, the Matching Pursuit algorithm and simple time-domain statistical analysis. Therefore, the proposed method should be considered as a promising approach for automatic EEG analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Does Context, Practice or Competition Affect Female Athletes’ Achievement Goal Dominance, Goal Pursuit, Burnout and Motivation?

    Directory of Open Access Journals (Sweden)

    Fernández-Rio Javier

    2017-10-01

    Full Text Available The goal of this study was to assess the effects of two different achievement sport contexts, practice and competition, on the motivational profile of professional/semi-professional athletes. Forty-eight Spanish national/international-level female athletes (basketball = 18; handball = 12; soccer = 11; volleyball = 7, mean age 25.14 ± 3.43 years, agreed to participate in the study. They completed a questionnaire, prior and after training and competition, to assess achievement goals, achievement goal dominance, goal pursuit, motivational climate, motivation, burnout and perceived recovery-exertion. Data analyses revealed that, both in practice and competition, these team-sport athletes overwhelmingly showed a strong mastery-approach achievement goal in dominance as well as in pursuit. A significant finding was that this group of national/international-level, professional/semi-professional athletes not only adopted a mastery-approach achievement goal, but they also actively pursued it. It is also remarkable that this profile remained stable at post-tests, even after a painful defeat in competition, which produced a significant negative effect on the athletes’ burnout (emotional and physical exhaustion and devaluation of sport participation and self-determined motivation. As expected, the difference between total recovery and perceived exertion significantly increased after practice and competition. National/international-level team-sport professional/semi-professional female athletes held and pursue stable mastery-approach goal dominance.

  9. LUM Smoother with Smooth Control for Noisy Image Sequences

    Directory of Open Access Journals (Sweden)

    Lukàč Rastislav

    2001-01-01

    Full Text Available This paper focuses on adaptive structure of LUM (lower-upper-middle smoothers for noisy image sequences. For the balance between noise suppression and signal-detail preservation, the LUM smoothers are widely used in smoothing applications. The amount of smoothing done by LUM smoothers is controlled by tuning parameter. However, the smoothing level is fixed for whole image. Thus, the excessive or insufficient smoothing can be performed. This problem is solved by a new method based on the adaptive controlled level of smoothing. A new method has excellent performance of the noise reduction in the environments corrupted by the impulse noise. In addition, minimal signal-detail and motion blurring can be observed. The performance of proposed method is evaluated through objective criteria and compared with traditional temporal, spatial, and spatiotemporal LUM smoothers.

  10. Moving least-squares corrections for smoothed particle hydrodynamics

    Directory of Open Access Journals (Sweden)

    Ciro Del Negro

    2011-12-01

    Full Text Available First-order moving least-squares are typically used in conjunction with smoothed particle hydrodynamics in the form of post-processing filters for density fields, to smooth out noise that develops in most applications of smoothed particle hydrodynamics. We show how an approach based on higher-order moving least-squares can be used to correct some of the main limitations in gradient and second-order derivative computation in classic smoothed particle hydrodynamics formulations. With a small increase in computational cost, we manage to achieve smooth density distributions without the need for post-processing and with higher accuracy in the computation of the viscous term of the Navier–Stokes equations, thereby reducing the formation of spurious shockwaves or other streaming effects in the evolution of fluid flow. Numerical tests on a classic two-dimensional dam-break problem confirm the improvement of the new approach.

  11. Single Locus Maintains Large Variation of Sex Reversal in Half-Smooth Tongue Sole (Cynoglossus semilaevis).

    Science.gov (United States)

    Jiang, Li; Li, Hengde

    2017-02-09

    Sex determination is a fundamental biological process for individual sex development and population sex ratios. However, for some species, the primary sex might be altered during development, and individuals can develop into the opposite sex. Sex reversal may happen in insects, reptiles, amphibians, and fishes. In half-smooth tongue sole ( Cynoglossus semilaevis ), some genetically female fish irreversibly reverse to pseudomales, resulting in higher costs in aquaculture owing to a lower growth rate of male fish during a 2-yr growth period. Here, we identified a locus with large controlling effect on sex reversal in the half-smooth tongue sole through genome-wide association study with high-density single nucleotide polymorphisms (SNPs). This SNP is located at the third intron of the F-box and leucine rich repeat protein 17 ( FBXL17 ) gene on the Z chromosome, and it has two alleles, A and T. Genetic females with Z A W genotypes will never reverse into phenotypic males, but those with Z T W genotypes can sometimes undergo sex reversal. This SNP explains 82.7% of the genetic variation, or 58.4% of the phenotypic variation. Based on our results, a reproductive management program could be developed to improve the phenotypic female ratio in aquaculture, and elucidate the mechanism of sex reversal in half-smooth tongue sole. We expect that these findings will have a substantial impact on the population management in many harvested species where sex reversal occurs. Copyright © 2017 Jiang and Li.

  12. Single Locus Maintains Large Variation of Sex Reversal in Half-Smooth Tongue Sole (Cynoglossus semilaevis

    Directory of Open Access Journals (Sweden)

    Li Jiang

    2017-02-01

    Full Text Available Sex determination is a fundamental biological process for individual sex development and population sex ratios. However, for some species, the primary sex might be altered during development, and individuals can develop into the opposite sex. Sex reversal may happen in insects, reptiles, amphibians, and fishes. In half-smooth tongue sole (Cynoglossus semilaevis, some genetically female fish irreversibly reverse to pseudomales, resulting in higher costs in aquaculture owing to a lower growth rate of male fish during a 2-yr growth period. Here, we identified a locus with large controlling effect on sex reversal in the half-smooth tongue sole through genome-wide association study with high-density single nucleotide polymorphisms (SNPs. This SNP is located at the third intron of the F-box and leucine rich repeat protein 17 (FBXL17 gene on the Z chromosome, and it has two alleles, A and T. Genetic females with ZAW genotypes will never reverse into phenotypic males, but those with ZTW genotypes can sometimes undergo sex reversal. This SNP explains 82.7% of the genetic variation, or 58.4% of the phenotypic variation. Based on our results, a reproductive management program could be developed to improve the phenotypic female ratio in aquaculture, and elucidate the mechanism of sex reversal in half-smooth tongue sole. We expect that these findings will have a substantial impact on the population management in many harvested species where sex reversal occurs.

  13. Adaptively smoothed seismicity earthquake forecasts for Italy

    Directory of Open Access Journals (Sweden)

    Yan Y. Kagan

    2010-11-01

    Full Text Available We present a model for estimation of the probabilities of future earthquakes of magnitudes m ≥ 4.95 in Italy. This model is a modified version of that proposed for California, USA, by Helmstetter et al. [2007] and Werner et al. [2010a], and it approximates seismicity using a spatially heterogeneous, temporally homogeneous Poisson point process. The temporal, spatial and magnitude dimensions are entirely decoupled. Magnitudes are independently and identically distributed according to a tapered Gutenberg-Richter magnitude distribution. We have estimated the spatial distribution of future seismicity by smoothing the locations of past earthquakes listed in two Italian catalogs: a short instrumental catalog, and a longer instrumental and historic catalog. The bandwidth of the adaptive spatial kernel is estimated by optimizing the predictive power of the kernel estimate of the spatial earthquake density in retrospective forecasts. When available and reliable, we used small earthquakes of m ≥ 2.95 to reveal active fault structures and 29 probable future epicenters. By calibrating the model with these two catalogs of different durations to create two forecasts, we intend to quantify the loss (or gain of predictability incurred when only a short, but recent, data record is available. Both forecasts were scaled to five and ten years, and have been submitted to the Italian prospective forecasting experiment of the global Collaboratory for the Study of Earthquake Predictability (CSEP. An earlier forecast from the model was submitted by Helmstetter et al. [2007] to the Regional Earthquake Likelihood Model (RELM experiment in California, and with more than half of the five-year experimental period over, the forecast has performed better than the others.

  14. CNP-pGC-cGMP-PDE3-cAMP Signal Pathway Upregulated in Gastric Smooth Muscle of Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Ying-Lan Cai

    2015-01-01

    Full Text Available Our previous studies have shown that CNP-NPR-B/pGC-cGMP is upregulated in the diabetic rats. The present study was designed to determine whether the upregulation of CNP-NPR-B/pGC-cGMP signal pathway affects cGMP-PDE3-cAMP signal pathway in diabetic gastric smooth muscle. The gastric smooth muscle motility was observed by using isometric measurement. PDEs expressions in diabetic gastric smooth muscle tissue were observed by using immunohistochemistry, Western blotting, and RT-PCR methods. The results demonstrated that the inhibitory effect of CNP on the spontaneous contraction of gastric antral circular smooth muscle was potentiated in STZ-induced diabetic rat. CNP-induced increase of cGMP and cAMP was much higher in diabetic gastric smooth muscle tissue than in controls. The expression of PDE3 is downregulated while the levels of gene expression of PDE1, PDE2, PDE4, and PDE5 were not altered in the diabetic gastric smooth muscle tissue. The results suggest that the sensitivity of gastric smooth muscle to CNP is potentiated via activation of CNP-pGC-cGMP-PDE3-cAMP signal pathway in STZ-induced diabetic rats, which may be associated with diabetes-induced gastric motility disorder.

  15. Efficient computation of smoothing splines via adaptive basis sampling

    KAUST Repository

    Ma, Ping

    2015-06-24

    © 2015 Biometrika Trust. Smoothing splines provide flexible nonparametric regression estimators. However, the high computational cost of smoothing splines for large datasets has hindered their wide application. In this article, we develop a new method, named adaptive basis sampling, for efficient computation of smoothing splines in super-large samples. Except for the univariate case where the Reinsch algorithm is applicable, a smoothing spline for a regression problem with sample size n can be expressed as a linear combination of n basis functions and its computational complexity is generally O(n3). We achieve a more scalable computation in the multivariate case by evaluating the smoothing spline using a smaller set of basis functions, obtained by an adaptive sampling scheme that uses values of the response variable. Our asymptotic analysis shows that smoothing splines computed via adaptive basis sampling converge to the true function at the same rate as full basis smoothing splines. Using simulation studies and a large-scale deep earth core-mantle boundary imaging study, we show that the proposed method outperforms a sampling method that does not use the values of response variables.

  16. Nodular smooth muscle metaplasia in multiple peritoneal endometriosis.

    Science.gov (United States)

    Kim, Hyun-Soo; Yoon, Gun; Ha, Sang Yun; Song, Sang Yong

    2015-01-01

    We report here an unusual presentation of peritoneal endometriosis with smooth muscle metaplasia as multiple protruding masses on the lateral pelvic wall. Smooth muscle metaplasia is a common finding in rectovaginal endometriosis, whereas in peritoneal endometriosis, smooth muscle metaplasia is uncommon and its nodular presentation on the pelvic wall is even rarer. To the best of our knowledge, this is the first case of nodular smooth muscle metaplasia occurring in peritoneal endometriosis. As observed in this case, when performing laparoscopic surgery in order to excise malignant tumors of intra-abdominal or pelvic organs, it can be difficult for surgeons to distinguish the metastatic tumors from benign nodular pelvic wall lesions, including endometriosis, based on the gross findings only. Therefore, an intraoperative frozen section biopsy of the pelvic wall nodules should be performed to evaluate the peritoneal involvement by malignant tumors. Moreover, this report implies that peritoneal endometriosis, as well as rectovaginal endometriosis, can clinically present as nodular lesions if obvious smooth muscle metaplasia is present. The pathological investigation of smooth muscle cells in peritoneal lesions can contribute not only to the precise diagnosis but also to the structure and function of smooth muscle cells and related cells involved in the histogenesis of peritoneal endometriosis.

  17. The Smoothing Hypothesis, Stock Returns and Risk in Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Lopo Martinez

    2011-01-01

    Full Text Available Income smoothing is defined as the deliberate normalization of income in order to reach a desired trend. If the smoothing causes more information to be reflected in the stock price, it is likely to improve the allocation of resources and can be a critical factor in investment decisions. This study aims to build metrics to determine the degree of smoothing in Brazilian public companies, to classify them as smoothing and non-smoothing companies and additionally to present evidence on the long-term relationship between the smoothing hypothesis and stock return and risk. Using the Economatica and CVM databases, this study focuses on 145 companies in the period 1998-2007. We find that Brazilian smoothers have a smaller degree of systemic risk than non-smoothers. In average terms, the beta of smoothers is significantly lower than non-smoothers. Regarding return, we find that the abnormal annualized returns of smoothers are significantly higher. We confirm differences in the groups by nonparametric and parametric tests in cross section or as time series, indicating that there is a statistically significant difference in performance in the Brazilian market between firms that do and do not engage in smoothing.

  18. Modeling the dispersion effects of contractile fibers in smooth muscles

    Science.gov (United States)

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

    2010-12-01

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

  19. Macrophage secretory products selectively stimulate dermatan sulfate proteoglycan production in cultured arterial smooth muscle cells

    International Nuclear Information System (INIS)

    Edwards, I.J.; Wagner, W.D.; Owens, R.T.

    1990-01-01

    Arterial dermatan sulfate proteoglycan has been shown to increase with atherosclerosis progression, but factors responsible for this increase are unknown. To test the hypothesis that smooth muscle cell proteoglycan synthesis may be modified by macrophage products, pigeon arterial smooth muscle cells were exposed to the media of either cholesteryl ester-loaded pigeon peritoneal macrophages or a macrophage cell line P388D1. Proteoglycans radiolabeled with [35S]sulfate and [3H]serine were isolated from culture media and smooth muscle cells and purified following precipitation with 1-hexadecylpyridinium chloride and chromatography. Increasing concentrations of macrophage-conditioned media were associated with a dose-response increase in [35S]sulfate incorporation into secreted proteoglycans, but there was no change in cell-associated proteoglycans. Incorporation of [3H]serine into total proteoglycan core proteins was not significantly different (5.2 X 10(5) dpm and 5.5 X 10(5) disintegrations per minute (dpm) in control and conditioned media-treated cultures, respectively), but selective effects were observed on individual proteoglycan types. Twofold increases in dermatan sulfate proteoglycan and limited degradation of chondroitin sulfate proteoglycan were apparent based on core proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunoinhibition studies indicated that interleukin-1 was involved in the modulation of proteoglycan synthesis by macrophage-conditioned media. These data provide support for the role of macrophages in alteration of the matrix proteoglycans synthesized by smooth muscle cells and provide a mechanism to account for the reported increased dermatan sulfate/chondroitin sulfate ratios in the developing atherosclerotic lesion

  20. Effects of nitrendipine on growth activity in cultured vascular smooth muscle cells.

    Science.gov (United States)

    Absher, M P; Baldor, L; Warshaw, D M

    1988-01-01

    Proliferation and migration of smooth muscle cells (SMCs) in the arterial wall may play a role in the development of atherosclerosis and hypertension. If cell migration and proliferation are dependent on extracellular calcium, then treatment with calcium channel blockers such as nitrendipine may alter these cellular responses. In the studies reported here, proliferation and migration activities were assessed in cultured bovine carotid artery smooth muscle cells exposed to nitrendipine. SMCs in long-term culture are characterized by periods of either stable or enhanced proliferative activity. During the stable periods, 1 microM nitrendipine has no effect on proliferation, but during periods of enhanced proliferation, 1 microM nitrendipine augments growth by approximately 20%. SMC migration rates and interdivision times were determined from analysis of time-lapse cinematography films. During stable periods of growth, cell migration rate was inversely related to interdivision time (i.e., fast migrating cells had the shortest interdivision times). Treatment with 1 microM nitrendipine abolished the relationship between migration rate and interdivision time and prolonged interdivision times. These data suggest that the ability of nitrendipine to alter SMC proliferation, interdivision time, and migration is dependent upon the overall proliferative state of the culture.

  1. Effect of hypertensive rat plasma on ion transport of cultured vascular smooth muscle

    International Nuclear Information System (INIS)

    Magargal, W.W.; Overbeck, H.W.

    1986-01-01

    We layered fresh, unprocessed plasma from healthy rats with early (less than or equal to 7 days) or benign, chronic (greater than 3 wk) one-kidney, one-clip hypertension and from paired one-kidney normotensive control rats over confluent primary-cultured rat aortic smooth muscle cells. Plasma from all rats increased cellular ouabain-sensitive 86 Rb + uptake and sodium content and decreased ouabain-insensitive 86 Rb + uptake compared with uptakes and content in the presence of balanced salt solution (P less than 0.01). Cells incubated in the presence of plasma from rats with early (P less than 0.02) or chronic hypertension (P less than 0.01) had significantly reduced ouabain-sensitive 86 Rb + uptake when compared with cells incubated in normotensive plasma, but their intracellular Na+ contents were not lower. We no longer detected this uptake difference when chronic hypertensives drank 0.9% NaCl instead of water. Plasma from hypertensive rats also altered ouabain-insensitive 86 Rb + uptake by the cultured cells. These findings of this new, reproducible, and specific assay system support the hypothesis that plasma factors inhibit the membrane sodium-potassium pump in vascular smooth muscle cells in this form of hypertension. The abnormality occurs in both early and chronic stages, but may not be related to sodium intake. The data also provide evidence for plasma factors in hypertension altering membrane K+ permeability

  2. Adaptive Smoothing in fMRI Data Processing Neural Networks

    DEFF Research Database (Denmark)

    Vilamala, Albert; Madsen, Kristoffer Hougaard; Hansen, Lars Kai

    2017-01-01

    Functional Magnetic Resonance Imaging (fMRI) relies on multi-step data processing pipelines to accurately determine brain activity; among them, the crucial step of spatial smoothing. These pipelines are commonly suboptimal, given the local optimisation strategy they use, treating each step...... by defining a smoothing step as a layer in these networks able to adaptively modulate the degree of smoothing required by each brain volume to better accomplish a given data analysis task. The viability is evaluated on real fMRI data where subjects did alternate between left and right finger tapping tasks....

  3. Tobacco constituents are mitogenic for arterial smooth-muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Becker, C.G.; Hajjar, D.P.; Hefton, J.M.

    1985-07-01

    Tobacco glycoprotein (TGP) purified from flue-cured tobacco leaves, tar-derived material (TAR), the water soluble, nondialyzable, delipidized extract of cigarette smoke condensate, rutin-bovine serum albumin conjugates, quercetin, and chlorogenic acid are mitogenic for bovine aortic smooth-muscle cells, but not adventitial fibroblasts. The mitogenicity appears to depend on polyphenol epitopes on carrier molecules. Ellagic acid, another plant polyphenol, inhibited arterial smooth-muscle proliferation. These results suggest that a number of ubiquitous, plant-derived substances may influence smooth-muscle cell proliferation in the arterial wall.

  4. Adaptive Smoothed Finite Elements (ASFEM) for history dependent material models

    International Nuclear Information System (INIS)

    Quak, W.; Boogaard, A. H. van den

    2011-01-01

    A successful simulation of a bulk forming process with finite elements can be difficult due to distortion of the finite elements. Nodal smoothed Finite Elements (NSFEM) are an interesting option for such a process since they show good distortion insensitivity and moreover have locking-free behavior and good computational efficiency. In this paper a method is proposed which takes advantage of the nodally smoothed field. This method, named adaptive smoothed finite elements (ASFEM), revises the mesh for every step of a simulation without mapping the history dependent material parameters. In this paper an updated-Lagrangian implementation is presented. Several examples are given to illustrate the method and to show its properties.

  5. Smooth solutions of the Navier-Stokes equations

    International Nuclear Information System (INIS)

    Pokhozhaev, S I

    2014-01-01

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

  6. Electrochemically replicated smooth aluminum foils for anodic alumina nanochannel arrays

    International Nuclear Information System (INIS)

    Biring, Sajal; Tsai, K-T; Sur, Ujjal Kumar; Wang, Y-L

    2008-01-01

    A fast electrochemical replication technique has been developed to fabricate large-scale ultra-smooth aluminum foils by exploiting readily available large-scale smooth silicon wafers as the masters. Since the adhesion of aluminum on silicon depends on the time of surface pretreatment in water, it is possible to either detach the replicated aluminum from the silicon master without damaging the replicated aluminum and master or integrate the aluminum film to the silicon substrate. Replicated ultra-smooth aluminum foils are used for the growth of both self-organized and lithographically guided long-range ordered arrays of anodic alumina nanochannels without any polishing pretreatment

  7. Smooth invariant densities for random switching on the torus

    Science.gov (United States)

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

    2018-04-01

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

  8. Projection pursuit water quality evaluation model based on chicken swam algorithm

    Science.gov (United States)

    Hu, Zhe

    2018-03-01

    In view of the uncertainty and ambiguity of each index in water quality evaluation, in order to solve the incompatibility of evaluation results of individual water quality indexes, a projection pursuit model based on chicken swam algorithm is proposed. The projection index function which can reflect the water quality condition is constructed, the chicken group algorithm (CSA) is introduced, the projection index function is optimized, the best projection direction of the projection index function is sought, and the best projection value is obtained to realize the water quality evaluation. The comparison between this method and other methods shows that it is reasonable and feasible to provide decision-making basis for water pollution control in the basin.

  9. Orthogonal matching pursuit applied to the deconvolution approach for the mapping of acoustic sources inverse problem.

    Science.gov (United States)

    Padois, Thomas; Berry, Alain

    2015-12-01

    Microphone arrays and beamforming have become a standard method to localize aeroacoustic sources. Deconvolution techniques have been developed to improve spatial resolution of beamforming maps. The deconvolution approach for the mapping of acoustic sources (DAMAS) is a standard deconvolution technique, which has been enhanced via a sparsity approach called sparsity constrained deconvolution approach for the mapping of acoustic sources (SC-DAMAS). In this paper, the DAMAS inverse problem is solved using the orthogonal matching pursuit (OMP) and compared with beamforming and SC-DAMAS. The resulting noise source maps show that OMP-DAMAS is an efficient source localization technique in the case of uncorrelated or correlated acoustic sources. Moreover, the computation time is clearly reduced as compared to SC-DAMAS.

  10. The pursuit of happiness measurement: a psychometric model based on psychophysiological correlates.

    Science.gov (United States)

    Pietro, Cipresso; Silvia, Serino; Giuseppe, Riva

    2014-01-01

    Everyone is interested in the pursuit of happiness, but the real problem for the researchers is how to measure it. Our aim was to deeply investigate happiness measurement through biomedical signals, using psychophysiological methods to objectify the happiness experiences measurements. The classic valence-arousal model of affective states to study happiness has been extensively used in psychophysiology. However, really few studies considered a real combination of these two dimensions and no study further investigated multidimensional models. More, most studies focused mainly on self-report to measure happiness and a deeper psychophysiological investigation on the dimensions of such an experience is still missing. A multidimensional model of happiness is presented and both the dimensions and the measures extracted within each dimension are comprehensively explained. This multidimensional model aims at being a milestone for future systematic study on psychophysiology of happiness and affective states.

  11. Vespertilionid bats control the width of their biosonar sound beam dynamically during prey pursuit

    DEFF Research Database (Denmark)

    Jakobsen, Lasse; Surlykke, Annemarie

    2010-01-01

    Animals using sound for communication emit directional signals, focusing most acoustic energy in one direction. Echolocating bats are listening for soft echoes from insects. Therefore, a directional biosonar sound beam greatly increases detection probability in the forward direction and decreases...... off-axis echoes. However, high directionality has context-specific disadvantages: at close range the detection space will be vastly reduced, making a broad beam favorable. Hence, a flexible system would be very advantageous. We investigated whether bats can dynamically change directionality...... of their biosonar during aerial pursuit of insects. We trained five Myotis daubentonii and one Eptesicus serotinus to capture tethered mealworms and recorded their echolocation signals with a multimicrophone array. The results show that the bats broaden the echolocation beam drastically in the terminal phase...

  12. Perspective: The missing link in academic career planning and development: pursuit of meaningful and aligned work.

    Science.gov (United States)

    Lieff, Susan J

    2009-10-01

    Retention of faculty in academic medicine is a growing challenge. It has been suggested that inattention to the humanistic values of the faculty is contributing to this problem. Professional development should consider faculty members' search for meaning, purpose, and professional fulfillment and should support the development of an ability to reflect on these issues. Ensuring the alignment of academic physicians' inner direction with their outer context is critical to professional fulfillment and effectiveness. Personal reflection on the synergy of one's strengths, passions, and values can help faculty members define meaningful work so as to enable clearer career decision making. The premise of this article is that an awareness of and the pursuit of meaningful work and its alignment with the academic context are important considerations in the professional fulfillment and retention of academic faculty. A conceptual framework for understanding meaningful work and alignment and ways in which that framework can be applied and taught in development programs are presented and discussed.

  13. Studying Islands: On Whose Terms? Some Epistemological and Methodological Challenges to the Pursuit of Island Studies

    Directory of Open Access Journals (Sweden)

    Godfrey Baldacchino

    2008-05-01

    Full Text Available The pursuit of nissology, or island studies, calls for a re-centering of focus from mainland to island, away from the discourse of conquest of mainlanders, giving voice and platform for the expression of island narratives. Yet, studying islands ‘on their own terms’, in spite of its predilection for “authenticity”, is fraught with epistemological and methodological difficulties. The insider/outsider distinction does not work all that well when it comes to islands, where hybridity is the norm. This paper seeks to extend this debate, grappling especially with the contributions of Grant McCall and Peter Hay to the sparse literature. Five dilemmas related to indigenous island geographies are presented and discussed, in a semi-autobiographical style.

  14. Nested Multi- and Many-Objective Optimisation of Team Track Pursuit Cycling

    Directory of Open Access Journals (Sweden)

    Markus Wagner

    2016-10-01

    Full Text Available Team pursuit track cycling is an elite sport that is part of the Summer Olympics. Teams race against each other on special tracks called velodromes. In this article, we create racing strategies that allow the team to complete the race in as little time as possible. In addition to the traditional minimisation of the race times, we consider the amount of energy that the riders have left at the end of the race. For the team coach this extension can have the benefit that a diverse set of trade-off strategies can be considered. For the optimisation approach, the added diversity can help to get over local optima.To solve this problem, we apply different state-of-the-art algorithms with problem-specific variation operators. It turns out that nesting algorithms is beneficial for achieving fast strategies reliably.

  15. An ensemble based nonlinear orthogonal matching pursuit algorithm for sparse history matching of reservoir models

    KAUST Repository

    Fsheikh, Ahmed H.

    2013-01-01

    A nonlinear orthogonal matching pursuit (NOMP) for sparse calibration of reservoir models is presented. Sparse calibration is a challenging problem as the unknowns are both the non-zero components of the solution and their associated weights. NOMP is a greedy algorithm that discovers at each iteration the most correlated components of the basis functions with the residual. The discovered basis (aka support) is augmented across the nonlinear iterations. Once the basis functions are selected from the dictionary, the solution is obtained by applying Tikhonov regularization. The proposed algorithm relies on approximate gradient estimation using an iterative stochastic ensemble method (ISEM). ISEM utilizes an ensemble of directional derivatives to efficiently approximate gradients. In the current study, the search space is parameterized using an overcomplete dictionary of basis functions built using the K-SVD algorithm.

  16. Orthogonal matching pursuit algorithm and power line noise suppression of magnetotelluric signal

    Science.gov (United States)

    Li, Guang; Tang, Jingtian

    2017-11-01

    Power-line noise is mainly comes from power systems and has become one of the most common noises during the acquisition of magnetotelluric (MT) signal, its components including a fundamental frequency signal and a lot of odd harmonics. There are trap circuits designed in most of the acquisition instruments to separate these noise, however, the fundamental frequency of the power line noise will fluctuate with the changing of load current, but the center frequency of the trap circuits are fixed, hence the MT data are still seriously disturbed by the power line noise. To mitigate the disturbance of power line noise, a novel denoising method was proposed based on orthogonal matching pursuit (OMP) algorithm. Semisynthetic experiments and real data obtained from Lu-Zong ore-concentration district illustrate that the proposed method can effectively suppress the power line noise while remain the useful MT signal, the apparent resistivity and phase curves are greatly improved over previous.

  17. Sparse Reconstruction of Regional Gravity Signal Based on Stabilized Orthogonal Matching Pursuit (SOMP)

    Science.gov (United States)

    Saadat, S. A.; Safari, A.; Needell, D.

    2016-06-01

    The main role of gravity field recovery is the study of dynamic processes in the interior of the Earth especially in exploration geophysics. In this paper, the Stabilized Orthogonal Matching Pursuit (SOMP) algorithm is introduced for sparse reconstruction of regional gravity signals of the Earth. In practical applications, ill-posed problems may be encountered regarding unknown parameters that are sensitive to the data perturbations. Therefore, an appropriate regularization method needs to be applied to find a stabilized solution. The SOMP algorithm aims to regularize the norm of the solution vector, while also minimizing the norm of the corresponding residual vector. In this procedure, a convergence point of the algorithm that specifies optimal sparsity-level of the problem is determined. The results show that the SOMP algorithm finds the stabilized solution for the ill-posed problem at the optimal sparsity-level, improving upon existing sparsity based approaches.

  18. Cooperative Surveillance and Pursuit Using Unmanned Aerial Vehicles and Unattended Ground Sensors

    Directory of Open Access Journals (Sweden)

    Jonathan Las Fargeas

    2015-01-01

    Full Text Available This paper considers the problem of path planning for a team of unmanned aerial vehicles performing surveillance near a friendly base. The unmanned aerial vehicles do not possess sensors with automated target recognition capability and, thus, rely on communicating with unattended ground sensors placed on roads to detect and image potential intruders. The problem is motivated by persistent intelligence, surveillance, reconnaissance and base defense missions. The problem is formulated and shown to be intractable. A heuristic algorithm to coordinate the unmanned aerial vehicles during surveillance and pursuit is presented. Revisit deadlines are used to schedule the vehicles’ paths nominally. The algorithm uses detections from the sensors to predict intruders’ locations and selects the vehicles’ paths by minimizing a linear combination of missed deadlines and the probability of not intercepting intruders. An analysis of the algorithm’s completeness and complexity is then provided. The effectiveness of the heuristic is illustrated through simulations in a variety of scenarios.

  19. Cooperative surveillance and pursuit using unmanned aerial vehicles and unattended ground sensors.

    Science.gov (United States)

    Las Fargeas, Jonathan; Kabamba, Pierre; Girard, Anouck

    2015-01-13

    This paper considers the problem of path planning for a team of unmanned aerial vehicles performing surveillance near a friendly base. The unmanned aerial vehicles do not possess sensors with automated target recognition capability and, thus, rely on communicating with unattended ground sensors placed on roads to detect and image potential intruders. The problem is motivated by persistent intelligence, surveillance, reconnaissance and base defense missions. The problem is formulated and shown to be intractable. A heuristic algorithm to coordinate the unmanned aerial vehicles during surveillance and pursuit is presented. Revisit deadlines are used to schedule the vehicles' paths nominally. The algorithm uses detections from the sensors to predict intruders' locations and selects the vehicles' paths by minimizing a linear combination of missed deadlines and the probability of not intercepting intruders. An analysis of the algorithm's completeness and complexity is then provided. The effectiveness of the heuristic is illustrated through simulations in a variety of scenarios.

  20. Conflict Mediation and the Pursuit Of Happiness in the Context of Human Rights

    Directory of Open Access Journals (Sweden)

    Carla Maria Franco Lameira Vitale

    2015-12-01

    Full Text Available This current work aims to contextualize the principle of the pursuit of happiness, institute that is not legalized in the Brazilian system, but it has been used to support important decisions. It is expressly provided in several human rights diplomas and international legislation, which supports the relevance of the subject. The concept of happiness is subjective, but the fact is that the man in his universal essence, search it as a form of satisfaction and pleasure. It also intends to demonstrate that mediation, as an appropriate method of resolving conflicts and guarantor way of access to justice can be an effective instrumet to achieve the desired happiness, to the extent that those involved are encouraged to seek the best solution to satisfies the personal desires and, above all, the dignity of the human person.

  1. Duytsche Mathematique and the Building of a New Society : Pursuits of Mathematics in the Seventeenth-Century Dutch Republic

    NARCIS (Netherlands)

    Dijksterhuis, Fokko J.; Cormack, Lesley B.; Schuster, John A.; Walton, Steven A.

    2017-01-01

    In the seventeenth-century Dutch Republic mathematicians and mathematics acquired notable social and intellectual prestige. They contributed to the establishment of a new state, first through practical projects of fortification, navigation, land management, and later also through learned pursuits in

  2. Users manual for the pursuit of the radiological status of the nuclear and radioactive facilities of the ININ

    International Nuclear Information System (INIS)

    Sotelo B, D.; Villarreal, J.E.

    1992-05-01

    The purpose of this program consists on a database that gives pursuit at the radiation levels in laboratories and facilities users of radioactive material or generators of ionizing radiations, introducing in it mensurations that were made in different departments, for its later analysis. (Author)

  3. Gender and the Dark Side of the Border in Laila Lalami’s Hope and other Dangerous Pursuits

    Directory of Open Access Journals (Sweden)

    Kareem Al-Jayikh Ali

    2016-12-01

    Full Text Available Starting from Arab-American women’s narratives, this study explores to what extent hegemonic history excludes and silences female Arab bodies and their relation to sexuality. It will also address the issue of present day migration, as reflected by Moroccan-American author Laila Lalami in her novel Hope and Other Dangerous Pursuits (2005.

  4. 76 FR 40419 - Culturally Significant Objects Imported for Exhibition Determinations: “Prints and the Pursuit of...

    Science.gov (United States)

    2011-07-08

    ... Modern Europe,'' imported from abroad for temporary exhibition within the United States, are of cultural... Determinations: ``Prints and the Pursuit of Knowledge in Early Modern Europe'' SUMMARY: Notice is hereby given of... also determine that the exhibition or display of the exhibit objects at the Harvard Art Museums...

  5. Recommendations for the successful pursuit of scholarship by pharmacy practice faculty members.

    Science.gov (United States)

    Bosso, John A; Hastings, Jan K; Speedie, Marilyn K; Rodriguez de Bittner, Magaly

    2015-02-17

    Scholarship has long been a basic expectation of faculty members at institutions of higher learning in the United States and elsewhere. This expectation is no less assumed in academic pharmacy. A number of organizations have verbalized and enforced this precept over the years.(1-3) For example, this expectation is spoken to directly in the American Council for Pharmacy Education's Accreditation Standards and Guidelines.(4) This expectation is further emphasized in the draft document of the accreditation standards to be implemented in 2016, in Standard 20. Specifically, Element 20.2 states: "The college or school must create an environment that both requires and promotes scholarship, and must also develop mechanisms to assess both the quantity and quality of faculty scholarly productivity."(5) The successful pursuit of scholarship by clinical faculty members (those engaged in both clinical practice and teaching, without regard to tenure or clinical track status) is challenging. (6-10) Thus, faculty member job descriptions or models should be designed so clinical faculty members can successfully meet all academic job expectations, including productive and meaningful scholarship. In 2012, an AACP Section of Teachers of Pharmacy Practice task force was charged with examining this issue and providing recommendations for models for clinical faculty members that would allow the successful pursuit of scholarship. The task force gathered information relating to the current state of affairs at a number of colleges and reviewed relevant literature. This information, along with personal experiences and much discussion and contemplation, led to some general observations as well as specific recommendations. This paper reiterates the task force's observations and recommendations and provides further detail regarding our interpretation of the findings and basis for the eventual recommendations to the section.

  6. Sex differences in prenatal stress effects on cocaine pursuit in rats.

    Science.gov (United States)

    Thomas, Mark B; Becker, Jill B

    2017-10-18

    Disruption of early-life ontogeny has severe and persistent consequences for the health of the developing organism. Both clinical and preclinical findings indicate that such interference can be caused by maternal stress during the gestation period (prenatal stress [PS]). In rats, PS facilitates the rewarding and neurochemical-stimulating effects of drugs, suggesting that PS may represent a risk factor for drug abuse in humans. Very little, however, is known about its effects in females, even though sex differences in drug susceptibility have been well documented in no PS (NPS) controls. Thus, we tested for independent effects and interactions between maternal restraint stress during the last week of gestation and sex on drug use with an extended regimen of drug self-administration. Male and female rats were provided daily access to a large but controlled amount of cocaine for seven weeks. Drug pursuit during the final week was used to indicate susceptibility to developing an addiction-like phenotype, based on reports that drug use becomes increasingly compulsive-like after weeks of testing. Overall, females satisfied more addiction-like criteria than males, and the same was true for PS rats when compared to NPS controls. In addition, sex and PS interacted to disproportionately promote drug pursuit of females with a history of PS. These results indicate that sex differences in drug susceptibility persist with continued drug exposure, and that PS widens this difference by more severely affecting females. In all, PS may be a risk factor for drug addiction in humans, and to a greater extent in women vs. men. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Is physical activity differentially associated with different types of sedentary pursuits?

    Science.gov (United States)

    Feldman, Debbie Ehrmann; Barnett, Tracie; Shrier, Ian; Rossignol, Michel; Abenhaim, Lucien

    2003-08-01

    To determine whether there is a relationship between the time adolescents spend in physical activity and time they spend in different sedentary pursuits: watching television, playing video games, working on computers, doing homework, and reading, taking into account the effect of part-time work on students' residual time. Cross-sectional cohort design. Seven hundred forty-three high school students from 2 inner-city public schools and 1 private school. Students completed a self-administered questionnaire that addressed time spent in physical activity, time spent in sedentary pursuits, musculoskeletal pain, and psychosocial issues and were also measured for height and weight. Main Outcome Measure Level of physical activity (low, moderate, high). There were more girls than boys in the low and moderate physical activity groups and more boys than girls in the high activity group. Ordinal logistic regression showed that increased time spent in "productive sedentary behavior" (reading or doing homework and working on computers) was associated with increased physical activity (odds ratio, 1.7; 95% confidence interval, 1.2-2.4), as was time spent working (odds ratio, 1.3; 95% confidence interval, 1.2-1.4). Time spent watching television and playing video games was not associated with decreased physical activity. Physical activity was not inversely associated with watching television or playing video games, but was positively associated with productive sedentary behavior and part-time work. Some students appear capable of managing their time better than others. Future studies should explore the ability of students to manage their time and also determine what characteristics are conducive to better time management.

  8. METHODOLOGY AND RESULTS OF MOBILE OBJECT PURSUIT PROBLEM SOLUTION WITH TWO-STAGE DYNAMIC SYSTEM

    Directory of Open Access Journals (Sweden)

    A. Kiselev Mikhail

    2017-01-01

    Full Text Available The experience of developing unmanned fighting vehicles indicates that the main challenge in this field reduces itself to creating the systems which can replace the pilot both as a sensor and as the operator of the flight. This problem can be partial- ly solved by introducing remote control, but there are certain flight segments where it can only be executed under fully inde- pendent control and data support due to various reasons, such as tight time, short duration, lack of robust communication, etc. Such stages also include close-range air combat maneuvering (CRACM - a key flight segment as far as the fighter's purpose is concerned, which also places the highest demands on the fighter's design. Until recently the creation of an unmanned fighter airplane has been a fundamentally impossible task due to the absence of sensors able to provide the necessary data support to control the fighter during CRACM. However, the development prospects of aircraft hardware (passive type flush antennae, op- tico-locating panoramic view stations are indicative of producing possible solutions to this problem in the nearest future. There- fore, presently the only fundamental impediment on the way to developing an unmanned fighting aircraft is the problem of cre- ating algorithms for automatic trajectory control during CRACM. This paper presents the strategy of automatic trajectory con- trol synthesis by a two-stage dynamic system aiming to reach the conditions specified with respect to an object in pursuit. It contains certain results of control algorithm parameters impact assessment in regards to the pursuit mission effectiveness. Based on the obtained results a deduction is drawn pertaining to the efficiency of the offered method and its possible utilization in au- tomated control of an unmanned fighting aerial vehicle as well as organizing group interaction during CRACM.

  9. Community impacts of anthropogenic disturbance: natural enemies exploit multiple routes in pursuit of invading herbivore hosts

    Directory of Open Access Journals (Sweden)

    Tavakoli Majid

    2010-10-01

    Full Text Available Abstract Background Biological invasions provide a window on the process of community assembly. In particular, tracking natural enemy recruitment to invading hosts can reveal the relative roles of co-evolution (including local adaptation and ecological sorting. We use molecular data to examine colonisation of northern Europe by the parasitoid Megastigmus stigmatizans following invasions of its herbivorous oak gallwasp hosts from the Balkans. Local host adaptation predicts that invading gallwasp populations will have been tracked primarily by sympatric Balkan populations of M. stigmatizans (Host Pursuit Hypothesis. Alternatively, ecological sorting allows parasitoid recruitment from geographically distinct populations with no recent experience of the invading hosts (Host Shift Hypothesis. Finally, we test for long-term persistence of parasitoids introduced via human trade of their hosts' galls (Introduction Hypothesis. Results Polymorphism diagnostic of different southern refugial regions was present in both mitochondrial and nuclear microsatellite markers, allowing us to identify the origins of northern European invaded range M. stigmatizans populations. As with their hosts, some invaded range populations showed genetic variation diagnostic of Balkan sources, supporting the Host Pursuit Hypothesis. In contrast, other invading populations had an Iberian origin, unlike their hosts in northern Europe, supporting the Host Shift Hypothesis. Finally, both British and Italian M. stigmatizans populations show signatures compatible with the Introduction Hypothesis from eastern Mediterranean sources. Conclusions These data reveal the continental scale of multi-trophic impacts of anthropogenic disturbance and highlight the fact that herbivores and their natural enemies may face very different constraints on range expansion. The ability of natural enemies to exploit ecologically-similar hosts with which they have had no historical association supports a

  10. Associated reactions during a visual pursuit position tracking task in hemiplegic and quadriplegic cerebral palsy.

    Science.gov (United States)

    Chiu, Hsiu-Ching; Halaki, Mark; O'Dwyer, Nicholas

    2013-04-30

    Most previous studies of associated reactions (ARs) in people with cerebral palsy have used observation scales, such as recording the degree of movement through observation. The sensitive quantitative method can detect ARs that are not amply visible. The aim of this study was to provide quantitative measures of ARs during a visual pursuit position tracking task. Twenty-three hemiplegia (H) (mean +/- SD: 21y 8m +/- 11y 10m), twelve quadriplegia (Q) (21y 5m +/- 10y 3m) and twenty-two subjects with normal development (N) (21y 2m +/- 10y 10m) participated in the study. An upper limb visual pursuit tracking task was used to study ARs. The participants were required to follow a moving target with a response cursor via elbow flexion and extension movements. The occurrence of ARs was quantified by the overall coherence between the movements of tracking and non-tracking limbs and the amount of movement due to ARs was quantified by the amplitude of movement the non-tracking limbs. The amplitude of movement of the non-tracking limb indicated that the amount of ARs was larger in the Q group than the H and N groups with no significant differences between the H and N groups. The amplitude of movement of the non-tracking limb was larger during non-dominant than dominant tracking in all three groups. Some movements in the non-tracking limb were correlated with the tracking limb (correlated ARs) and some movements that were not correlated with the tracking limb (uncorrelated ARs). The correlated ARs comprised less than 40% of the total ARs for all three groups. Correlated ARs were negatively associated with clinical evaluations, but not the uncorrelated ARs. The correlated and uncorrelated ARs appear to have different relationships with clinical evaluations, implying the effect of ARs on upper limb activities could be varied.

  11. Sensor-Based Vibration Signal Feature Extraction Using an Improved Composite Dictionary Matching Pursuit Algorithm

    Directory of Open Access Journals (Sweden)

    Lingli Cui

    2014-09-01

    Full Text Available This paper presents a new method for a composite dictionary matching pursuit algorithm, which is applied to vibration sensor signal feature extraction and fault diagnosis of a gearbox. Three advantages are highlighted in the new method. First, the composite dictionary in the algorithm has been changed from multi-atom matching to single-atom matching. Compared to non-composite dictionary single-atom matching, the original composite dictionary multi-atom matching pursuit (CD-MaMP algorithm can achieve noise reduction in the reconstruction stage, but it cannot dramatically reduce the computational cost and improve the efficiency in the decomposition stage. Therefore, the optimized composite dictionary single-atom matching algorithm (CD-SaMP is proposed. Second, the termination condition of iteration based on the attenuation coefficient is put forward to improve the sparsity and efficiency of the algorithm, which adjusts the parameters of the termination condition constantly in the process of decomposition to avoid noise. Third, composite dictionaries are enriched with the modulation dictionary, which is one of the important structural characteristics of gear fault signals. Meanwhile, the termination condition of iteration settings, sub-feature dictionary selections and operation efficiency between CD-MaMP and CD-SaMP are discussed, aiming at gear simulation vibration signals with noise. The simulation sensor-based vibration signal results show that the termination condition of iteration based on the attenuation coefficient enhances decomposition sparsity greatly and achieves a good effect of noise reduction. Furthermore, the modulation dictionary achieves a better matching effect compared to the Fourier dictionary, and CD-SaMP has a great advantage of sparsity and efficiency compared with the CD-MaMP. The sensor-based vibration signals measured from practical engineering gearbox analyses have further shown that the CD-SaMP decomposition and

  12. Estimate of K-functionals and modulus of smoothness constructed ...

    Indian Academy of Sciences (India)

    2016-08-26

    functional and a modulus of smoothness for the Dunkl transform on Rd. Author Affiliations. M El Hamma1 R Daher1. Department of Mathematics, Faculty of Sciences Aïn Chock, University of Hassan II, Casablanca, Morocco. Dates.

  13. Calcium-sensitivity of smooth muscle contraction in the isolated ...

    African Journals Online (AJOL)

    sensitivity of smooth muscle contraction were studied in the isolated perfused rat tail artery, employing the activators noradrenaline (NA) (3ìM) sand potassium chloride (KC1) (100mM). Experiments were conduced in Ca2+ - buffered saline.

  14. Carrier tracking by smoothing filter improves symbol SNR

    Science.gov (United States)

    Pomalaza-Raez, Carlos A.; Hurd, William J.

    1986-01-01

    The potential benefit of using a smoothing filter to estimate carrier phase over use of phase locked loops (PLL) is determined. Numerical results are presented for the performance of three possible configurations of the deep space network advanced receiver. These are residual carrier PLL, sideband aided residual carrier PLL, and finally sideband aiding with a Kalman smoother. The average symbol signal to noise ratio (SNR) after losses due to carrier phase estimation error is computed for different total power SNRs, symbol rates and symbol SNRs. It is found that smoothing is most beneficial for low symbol SNRs and low symbol rates. Smoothing gains up to 0.4 dB over a sideband aided residual carrier PLL, and the combined benefit of smoothing and sideband aiding relative to a residual carrier loop is often in excess of 1 dB.

  15. Carrier tracking by smoothing filter can improve symbol SNR

    Science.gov (United States)

    Hurd, W. J.; Pomalaza-Raez, C. A.

    1985-01-01

    The potential benefit of using a smoothing filter to estimate carrier phase over use of phase locked loops (PLL) is determined. Numerical results are presented for the performance of three possible configurations of the deep space network advanced receiver. These are residual carrier PLL, sideband aided residual carrier PLL, and finally sideband aiding with a Kalman smoother. The average symbol signal to noise ratio (CNR) after losses due to carrier phase estimation error is computed for different total power SNRs, symbol rates and symbol SNRs. It is found that smoothing is most beneficial for low symbol SNRs and low symbol rates. Smoothing gains up to 0.4 dB over a sideband aided residual carrier PLL, and the combined benefit of smoothing and sideband aiding relative to a residual carrier loop is often in excess of 1 dB.

  16. calcium-sensitivity of smooth muscle contraction in the isolated ...

    African Journals Online (AJOL)

    Dr Olaleye

    sensitivity of smooth muscle contraction were studied in the isolated perfused rat tail artery, employing the activators noradrenaline (NA) (3μM) sand potassium chloride (KC1) (100mM). Experiments were conduced in Ca2+ - buffered saline.

  17. Hospital to Home: Plan for a Smooth Transition

    Science.gov (United States)

    HOSPITAL TO HOME Plan for a Smooth Transition R eturning home from a hospital stay can result in unexpected challenges for many seniors. Finding themselves back at home after a hospital stay, many older adults struggle to manage their ...

  18. Myosin Va Plays a Role in Nitrergic Smooth Muscle Relaxation in Gastric Fundus and Corpora Cavernosa of Penis

    Science.gov (United States)

    Carew, Josephine A.; Goyal, Raj K.; Sullivan, Maryrose P.

    2014-01-01

    The intracellular motor protein myosin Va is involved in nitrergic neurotransmission possibly by trafficking of neuronal nitric oxide synthase (nNOS) within the nerve terminals. In this study, we examined the role of myosin Va in the stomach and penis, proto-typical smooth muscle organs in which nitric oxide (NO) mediated relaxation is critical for function. We used confocal microscopy and co-immunoprecipitation of tissue from the gastric fundus (GF) and penile corpus cavernosum (CCP) to localize myosin Va with nNOS and demonstrate their molecular interaction. We utilized in vitro mechanical studies to test whether smooth muscle relaxations during nitrergic neuromuscular neurotransmission is altered in DBA (dilute, brown, non-agouti) mice which lack functional myosin Va. Myosin Va was localized in nNOS-positive nerve terminals and was co-immunoprecipitated with nNOS in both GF and CCP. In comparison to C57BL/6J wild type (WT) mice, electrical field stimulation (EFS) of precontracted smooth muscles of GF and CCP from DBA animals showed significant impairment of nitrergic relaxation. An NO donor, Sodium nitroprusside (SNP), caused comparable levels of relaxation in smooth muscles of WT and DBA mice. These normal postjunctional responses to SNP in DBA tissues suggest that impairment of smooth muscle relaxation resulted from inhibition of NO synthesis in prejunctional nerve terminals. Our results suggest that normal physiological processes of relaxation of gastric and cavernosal smooth muscles that facilitate food accommodation and penile erection, respectively, may be disrupted under conditions of myosin Va deficiency, resulting in complications like gastroparesis and erectile dysfunction. PMID:24516539

  19. Smoothing the Sample Autocorrelation of Long-Range-Dependent Traffic

    Directory of Open Access Journals (Sweden)

    Ming Li

    2013-01-01

    Full Text Available This paper depicts our work in smoothing the sample autocorrelation function (ACF of traffic. The experimental results exhibit that the sample ACF of traffic may be smoothed by the way of average. In addition, the results imply that the sum of sample ACFs of traffic convergences. Considering that the traffic data used in this research is long-range dependent (LRD, the latter may be meaningful for the theoretical research of LRD traffic.

  20. Global smoothness preservation and the variation-diminishing property

    Directory of Open Access Journals (Sweden)

    Gavrea Ioan

    1999-01-01

    Full Text Available In the center of our paper are two counterexamples showing the independence of the concepts of global smoothness preservation and variation diminution for sequences of approximation operators. Under certain additional assumptions it is shown that the variation-diminishing property is the stronger one. It is also demonstrated, however, that there are positive linear operators giving an optimal pointwise degree of approximation, and which preserve global smoothness, monotonicity and convexity, but are not variation-diminishing.

  1. Some remarks on smooth renormings of Banach spaces

    Czech Academy of Sciences Publication Activity Database

    Hájek, Petr Pavel; Russo, T.

    2017-01-01

    Roč. 455, č. 2 (2017), s. 1272-1284 ISSN 0022-247X R&D Projects: GA ČR GA16-07378S Institutional support: RVO:67985840 Keywords : Fréchet smooth * approximation of norms * Ck-smooth norm Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.064, year: 2016 http://www.sciencedirect.com/science/article/pii/S0022247X17305462?via%3Dihub

  2. Some remarks on smooth renormings of Banach spaces

    Czech Academy of Sciences Publication Activity Database

    Hájek, Petr Pavel; Russo, T.

    2017-01-01

    Roč. 455, č. 2 (2017), s. 1272-1284 ISSN 0022-247X R&D Projects: GA ČR GA16-07378S Institutional support: RVO:67985840 Keywords : Fréchet smooth * approximation of norms * Ck-smooth norm Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.064, year: 2016 http://www. sciencedirect .com/science/article/pii/S0022247X17305462?via%3Dihub

  3. Smooth maps of a foliated manifold in a symplectic manifold

    Indian Academy of Sciences (India)

    Abstract. Let M be a smooth manifold with a regular foliation F and a 2-form ω which induces closed forms on the leaves of F in the leaf topology. A smooth map f : (M, F) −→ (N,σ) in a symplectic manifold (N,σ) is called a foliated symplectic immersion if f restricts to an immersion on each leaf of the foliation and further, the.

  4. Cyclic mechanical strain-induced proliferation and migration of human airway smooth muscle cells: role of EMMPRIN and MMPs.

    Science.gov (United States)

    Hasaneen, Nadia A; Zucker, Stanley; Cao, Jian; Chiarelli, Christian; Panettieri, Reynold A; Foda, Hussein D

    2005-09-01

    Airway smooth muscle (ASM) proliferation and migration are major components of airway remodeling in asthma. Asthmatic airways are exposed to mechanical strain, which contributes to their remodeling. Matrix metalloproteinase (MMP) plays an important role in remodeling. In the present study, we examined if the mechanical strain of human ASM (HASM) cells contributes to their proliferation and migration and the role of MMPs in this process. HASM were exposed to mechanical strain using the FlexCell system. HASM cell proliferation, migration and MMP release, activation, and expression were assessed. Our results show that cyclic strain increased the proliferation and migration of HASM; cyclic strain increased release and activation of MMP-1, -2, and -3 and membrane type 1-MMP; MMP release was preceded by an increase in extracellular MMP inducer; Prinomastat [a MMP inhibitor (MMPI)] significantly decreased cyclic strain-induced proliferation and migration of HASM; and the strain-induced increase in the release of MMPs was accompanied by an increase in tenascin-C release. In conclusion, cyclic mechanical strain plays an important role in HASM cell proliferation and migration. This increase in proliferation and migration is through an increase in MMP release and activation. Pharmacological MMPIs should be considered in the pursuit of therapeutic options for airway remodeling in asthma.

  5. The evolutionary origin of bilaterian smooth and striated myocytes

    Science.gov (United States)

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

    2016-01-01

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

  6. Gastric Smooth Muscle Hamartomas Mimicking Polyps in a Dog: A Case Description and a Review of the Literature

    Directory of Open Access Journals (Sweden)

    Marian A. Taulescu

    2013-01-01

    Full Text Available This report presents a case of two smooth muscle hamartomas of the stomach in a 10-year-old male Boxer. The clinical history of the animal was of chronic vomiting, weight loss, and intermittent gastric distension, and it died because of chronic and congestive heart failure. Gross, histology, and immunohistochemistry (IHC exams were performed. On necropsy, in the pyloric region of the stomach, two closely related polypoid growths between 10 and 15 mm in diameter were identified. On the cut sections, both polyps presented white to gray color, with homogenous architecture and well-defined limits. The thickness of the submucosal layer was seen to be increased to 1 cm. No other gastric alterations were identified by the necropsy exam. Histologically, both masses growth consisted of hyperplastic glands lined by foveolar epithelium, arranged in a papillary or branching pattern, and supported by a core of well-vascularised and marked smooth muscle tissue interspersed between glands. No dysplastic cells and mitotic figures were observed in these lesions. Immunohistochemistry revealed a strong cytoplasm labelling for smooth muscle actin of the bundles around the mucosal glands. To our knowledge, this is the first report of smooth muscle hamartomas mimicking multiple gastric polyps in dogs.

  7. Tetraspanin CD9 regulates cell contraction and actin arrangement via RhoA in human vascular smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    Michael J Herr

    Full Text Available The most prevalent cardiovascular diseases arise from alterations in vascular smooth muscle cell (VSMC morphology and function. Tetraspanin CD9 has been previously implicated in regulating vascular pathologies; however, insight into how CD9 may regulate adverse VSMC phenotypes has not been provided. We utilized a human model of aortic smooth muscle cells to understand the consequences of CD9 deficiency on VSMC phenotypes. Upon knocking down CD9, the cells developed an abnormally small and rounded morphology. We determined that this morphological change was due to a lack of typical parallel actin arrangement. We also found similar total RhoA but decreased GTP-bound (active RhoA levels in CD9 deficient cells. As a result, cells lacking a full complement of CD9 were less contractile than their control treated counterparts. Upon restoration of RhoA activity in the CD9 deficient cells, the phenotype was reversed and cell contraction was restored. Conversely, inhibition of RhoA activity in the control cells mimicked the CD9-deficient cell phenotype. Thus, alteration in CD9 expression was sufficient to profoundly disrupt cellular actin arrangement and endogenous cell contraction by interfering with RhoA signaling. This study provides insight into how CD9 may regulate previously described vascular smooth muscle cell pathophysiology.

  8. Fuzzy Perfect Mappings and Q-Compactness in Smooth Fuzzy Topological Spaces

    Directory of Open Access Journals (Sweden)

    C. Kalaivani

    2014-03-01

    Full Text Available We point out that the product of two fuzzy closed sets of smooth fuzzy topological spaces need not be fuzzy closed with respect to the the existing notion of product smooth fuzzy topology. To get this property, we introduce a new suitable product smooth fuzzy topology. We investigate whether F1×F2 and (F,H are weakly smooth fuzzy continuity whenever F1, F2, F and H are weakly smooth fuzzy continuous. Using this new product smooth fuzzy topology, we define smooth fuzzy perfect mapping and prove that composition of two smooth fuzzy perfect mappings is smooth fuzzy perfect under some additional conditions. We also introduce two new notions of compactness called Q-compactness and Q-α-compactness; and discuss the compactness of the image of a Q-compact set (Q-α-compact set under a weakly smooth fuzzy continuous function ((α,β-weakly smooth fuzzy continuous function.

  9. Intermittent Smoothing Approaches for Wind Power Output: A Review

    Directory of Open Access Journals (Sweden)

    Muhammad Jabir

    2017-10-01

    Full Text Available Wind energy is one of the most common types of renewable energy resource. Due to its sustainability and environmental benefits, it is an emerging source for electric power generation. Rapid and random changes of wind speed makes it an irregular and inconsistent power source when connected to the grid, causing different technical problems in protection, power quality and generation dispatch control. Due to these problems, effective intermittent smoothing approaches for wind power output are crucially needed to minimize such problems. This paper reviews various intermittent smoothing approaches used in smoothing the output power fluctuations caused by wind energy. Problems associated with the inclusion of wind energy resources to grid are also briefly reviewed. From this review, it has been found that battery energy storage system is the most suitable and effective smoothing approach, provided that an effective control strategy is available for optimal utilization of battery energy system. This paper further demonstrates different control strategies built for battery energy storage system to obtain the smooth output wind power.

  10. Goal pursuit, goal adjustment, and affective well-being following lower limb amputation.

    Science.gov (United States)

    Coffey, Laura; Gallagher, Pamela; Desmond, Deirdre; Ryall, Nicola

    2014-05-01

    This study examined the relationships between tenacious goal pursuit (TGP), flexible goal adjustment (FGA), and affective well-being in a sample of individuals with lower limb amputations. Cross-sectional, quantitative. Ninety-eight patients recently admitted to a primary prosthetic rehabilitation programme completed measures of TGP, FGA, positive affect, and negative affect. Hierarchical regression analyses revealed that TGP and FGA accounted for a significant proportion of the variance in both positive and negative affect, controlling for sociodemographic and clinical characteristics. TGP was significantly positively associated with positive affect, while FGA was significantly negatively associated with negative affect. Moderated regression analyses indicated that the beneficial effect of FGA on negative affect was strongest at high levels of amputation-related pain intensity and low levels of TGP. TGP and FGA appear to influence subjective well-being in different ways, with TGP promoting the experience of positive affect and FGA buffering against negative affect. TGP and FGA may prove useful in identifying individuals at risk of poor affective outcomes following lower limb amputation and represent important targets for intervention in this patient group. What is already known on this subject? The loss of a limb has a significant impact on several important life domains. Although some individuals experience emotional distress following amputation, the majority adjust well to their limb loss, with some achieving positive change or growth as a result of their experiences. Theories of self-regulation propose that disruptions in goal attainment have negative affective consequences. The physical, social, and psychological upheaval caused by limb loss is likely to threaten the attainment of valued goals, which may leave individuals vulnerable to negative psychosocial outcomes if they do not regulate their goals in response to these challenges. According to the dual

  11. Corporate entrepreneurship orientation and the pursuit of innovating opportunities in Botswana

    Directory of Open Access Journals (Sweden)

    Melodi Botha

    2011-12-01

    Full Text Available Purpose and objectives: A causal relationship between the independent variable (introduction of innovation and the dependent variable (Corporate Entrepreneurship orientation is explored by addressing the question: Do companies in Botswana have a corporate entrepreneurship (CE orientation that leads them to pursue innovating opportunities? The primary objective is to investigate how CE orientation in companies in Botswana is linked to individual employees' pursuit of innovation within corporate boundaries. Secondary objectives are to identify the prerequisites and factors of CE orientation, individual employees' perceptions and the importance of innovation factors in established companies. Problem investigated: To determine whether existing firms in Botswana represent the concept of an entrepreneurial company within the sphere of corporate entrepreneurship by pursuing innovating opportunities. The intention is to identify the knowledge, attitudes and beliefs of individuals as potential corporate entrepreneurs, their ability to be innovative and how such innovation is brought to fruition. Design and methodology: To obtain quantifiable measures of the link between CE orientation and innovation, a quantitative approach is used: a formalised, cross-sectional research design. The sample consists of 100 individuals at supervisory levels and above in large corporate companies, from eight different provinces in Botswana. A research instrument is used and convenience sampling employed. Factor analysis is performed on the questionnaire to determine its validity and reliability. A Pearson correlation coefficient test is conducted on the three factors identified in factor analysis. The chi-square test and T-test (Mann-Whitney U test are used to illustrate the statistically significant differences between the different variables and factors. Findings and implications: This paper proves the inextricable link between CE orientation and the pursuit of innovation

  12. Design and utilisation of protocols to characterise dynamic PET uptake of two tracers using basis pursuit

    Science.gov (United States)

    Bell, Christopher; Puttick, Simon; Rose, Stephen; Smith, Jye; Thomas, Paul; Dowson, Nicholas

    2017-06-01

    Imaging using more than one biological process using PET could be of great utility, but despite previously proposed approaches to dual-tracer imaging, it is seldom performed. The alternative of performing multiple scans is often infeasible for clinical practice or even in research studies. Dual-tracer PET scanning allows for multiple PET radiotracers to be imaged within the same imaging session. In this paper we describe our approach to utilise the basis pursuit method to aid in the design of dual-tracer PET imaging experiments, and later in separation of the signals. The advantage of this approach is that it does not require a compartment model architecture to be specified or even that both signals are distinguishable in all cases. This means the method for separating dual-tracer signals can be used for many feasible and useful combinations of biology or radiotracer, once an appropriate scanning protocol has been decided upon. Following a demonstration in separating the signals from two consecutively injected radionuclides in a controlled experiment, phantom and list-mode mouse experiments demonstrated the ability to test the feasibility of dual-tracer imaging protocols for multiple injection delays. Increases in variances predicted for kinetic macro-parameters V D and K I in brain and tumoral tissue were obtained when separating the synthetically combined data. These experiments confirmed previous work using other approaches that injections delays of 10-20 min ensured increases in variance were kept minimal for the test tracers used. On this basis, an actual dual-tracer experiment using a 20 min delay was performed using these radio tracers, with the kinetic parameters (V D and K I) extracted for each tracer in agreement with the literature. This study supports previous work that dual-tracer PET imaging can be accomplished provided certain constraints are adhered to. The utilisation of basis pursuit techniques, with its removed need to specify a model

  13. Developmental origins of colon smooth muscle dysfunction in IBS-like rats.

    Science.gov (United States)

    Li, Qingjie; Winston, John H; Sarna, Sushil K

    2013-10-01

    Epidemiological studies show that subsets of adult and pediatric patients with irritable bowel syndrome (IBS) have prior exposures to psychological or inflammatory stress. We investigated the cellular mechanisms of colonic smooth muscle dysfunction in adult rats subjected to neonatal inflammation. Ten-day-old male rat pups received 2,4,6-trinitrobenzene sulfonic acid to induce colonic inflammation. Colonic circular smooth muscle strips were obtained 6 to 8 wk later. We found that about half of the neonate pups subjected to inflammatory insult showed a significant increase in expression of the pore-forming α1C-subunit of Cav1.2b channels in adult life. These were the same rats in whom Vip mRNA increased in the colon muscularis externae. Additional experiments showed reduced interaction of histone deacetylase (HDAC) 3 with α1C1b promoter that increased the acetylation of histone H3 lysine 9 (H3K9) in the core promoter region. Vasoactive intestinal peptide (VIP) treatment of naïve muscularis externae swiftly recruited CREB-binding protein (CBP) to the α1C1b promoter and dissociated HDAC3 from this region to initiate transcription. The CBP interaction with the α1C1b promoter was transient, but the dissociation of HDAC3 persisted to sustain H3K9 hyperacetylation and increase in transcription. Intraperitoneal treatment of adult naïve rats with butyrate mimicked the effects of neonatal colon inflammation. We concluded that neonatal inflammation upregulates VIP in the colon muscularis externae, which modulates epigenetic events at the α1C1b promoter to activate α1C1b gene transcription. Inflammatory insult in early life may be one of the etiologies of smooth muscle dysfunction in adult life, which contributes to the altered motility function in patients with diarrhea-predominant IBS.

  14. The expression of functional postsynaptic α2-adrenoceptors in the corpus cavernosum smooth muscle

    Science.gov (United States)

    Gupta, Sandeep; Moreland, Robert B; Yang, Stone; Gallant, Cynthia M; Goldstein, Irwin; Traish, Abdulmaged

    1998-01-01

    The purpose of this study was to determine if corpus cavernosum smooth muscle expresses functional postsynaptic α2-adrenoceptors (AR).The α2-adrenoceptor agonist UK 14,304 elicited concentration-dependent contractions in rabbit corpus cavernosum smooth muscle (CCSM). The half-maximal response occurred at 0.32±0.03 μM and the maximum contraction at 10 μM UK 14,304.Pretreatment of CCSM strips with selective α2-adrenoceptor antagonists, rauwolscine and RS-15385, produced rightward shifts in the dose-response curves to UK 14,304 (pA2 values 7.1 and 8.5, respectively). In contrast, these antagonists did not alter contraction induced by the α1-adrenoceptor agonist phenylephrine (PE) or oxymetazoline. UK 14,304-induced contractions were also inhibited by prazosin (pA2=9.08).UK 14,304-induced contractions, unlike those to PE, were highly dependent on the presence of extracellular Ca2+.[3H]-rauwolscine bound to CCSM membranes with high affinity (Kd=1.5 nM). [3H]-rauwolscine binding was displaced by unlabelled rauwolscine, RS-15385, UK 14,304 and prazosin, but not by PE.UK 14,304 inhibited forskolin and prostaglandin E1 (PGE1)-induced increases in intracellular cyclic AMP concentration in primary cultures of rabbit CCSM cells.These results demonstrate that CCSM expresses Gi-coupled postsynaptic α2-adrenoceptors, and activation of these receptors causes contraction of trabecular smooth muscle. PMID:9559910

  15. Smoothing the payoff for efficient computation of Basket option prices

    KAUST Repository

    Bayer, Christian

    2017-07-22

    We consider the problem of pricing basket options in a multivariate Black–Scholes or Variance-Gamma model. From a numerical point of view, pricing such options corresponds to moderate and high-dimensional numerical integration problems with non-smooth integrands. Due to this lack of regularity, higher order numerical integration techniques may not be directly available, requiring the use of methods like Monte Carlo specifically designed to work for non-regular problems. We propose to use the inherent smoothing property of the density of the underlying in the above models to mollify the payoff function by means of an exact conditional expectation. The resulting conditional expectation is unbiased and yields a smooth integrand, which is amenable to the efficient use of adaptive sparse-grid cubature. Numerical examples indicate that the high-order method may perform orders of magnitude faster than Monte Carlo or Quasi Monte Carlo methods in dimensions up to 35.

  16. Testing for cubic smoothing splines under dependent data.

    Science.gov (United States)

    Nummi, Tapio; Pan, Jianxin; Siren, Tarja; Liu, Kun

    2011-09-01

    In most research on smoothing splines the focus has been on estimation, while inference, especially hypothesis testing, has received less attention. By defining design matrices for fixed and random effects and the structure of the covariance matrices of random errors in an appropriate way, the cubic smoothing spline admits a mixed model formulation, which places this nonparametric smoother firmly in a parametric setting. Thus nonlinear curves can be included with random effects and random coefficients. The smoothing parameter is the ratio of the random-coefficient and error variances and tests for linear regression reduce to tests for zero random-coefficient variances. We propose an exact F-test for the situation and investigate its performance in a real pine stem data set and by simulation experiments. Under certain conditions the suggested methods can also be applied when the data are dependent. © 2010, The International Biometric Society.

  17. Doppler distortion correction based on microphone array and matching pursuit algorithm for a wayside train bearing monitoring system

    International Nuclear Information System (INIS)

    Liu, Xingchen; Hu, Zhiyong; He, Qingbo; Zhang, Shangbin; Zhu, Jun

    2017-01-01

    Doppler distortion and background noise can reduce the effectiveness of wayside acoustic train bearing monitoring and fault diagnosis. This paper proposes a method of combining a microphone array and matching pursuit algorithm to overcome these difficulties. First, a dictionary is constructed based on the characteristics and mechanism of a far-field assumption. Then, the angle of arrival of the train bearing is acquired when applying matching pursuit to analyze the acoustic array signals. Finally, after obtaining the resampling time series, the Doppler distortion can be corrected, which is convenient for further diagnostic work. Compared with traditional single-microphone Doppler correction methods, the advantages of the presented array method are its robustness to background noise and its barely requiring pre-measuring parameters. Simulation and experimental study show that the proposed method is effective in performing wayside acoustic bearing fault diagnosis. (paper)

  18. A User Guide for Smoothing Air Traffic Radar Data

    Science.gov (United States)

    Bach, Ralph E.; Paielli, Russell A.

    2014-01-01

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

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

    Science.gov (United States)

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

    2008-05-01

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

  20. In pursuit of a science of agriculture: the role of statistics in field experiments.

    Science.gov (United States)

    Parolini, Giuditta

    2015-09-01

    Since the beginning of the twentieth century statistics has reshaped the experimental cultures of agricultural research taking part in the subtle dialectic between the epistemic and the material that is proper to experimental systems. This transformation has become especially relevant in field trials and the paper will examine the British agricultural institution, Rothamsted Experimental Station, where statistical methods nowadays popular in the planning and analysis of field experiments were developed in the 1920s. At Rothamsted statistics promoted randomisation over systematic arrangements, factorisation over one-question trials, and emphasised the importance of the experimental error in assessing field trials. These changes in methodology transformed also the material culture of agricultural science, and a new body, the Field Plots Committee, was created to manage the field research of the agricultural institution. Although successful, the vision of field experimentation proposed by the Rothamsted statisticians was not unproblematic. Experimental scientists closely linked to the farming community questioned it in favour of a field research that could be more easily understood by farmers. The clash between the two agendas reveals how the role attributed to statistics in field experimentation defined different pursuits of agricultural research, alternately conceived of as a scientists' science or as a farmers' science.

  1. Pursuit of communal values in an agentic manner: A way to happiness?

    Directory of Open Access Journals (Sweden)

    Andrea Elisabeth Abele

    2014-11-01

    Full Text Available The present research studies the association between traits, values and life satisfaction. While values should influence the direction of an individual’s goals and behaviour, his/her traits impact effort expenditure, efficiency and persistence in goal-pursuit. We apply the framework of the Big Two of agency and communion (Bakan, 1966 for distinguishing the content of values and traits. While agentic content refers to qualities relevant for goal-attainment, such as assertiveness, competence or persistence, communal content refers to qualities relevant for the establishment and maintenance of social relationships, such as being friendly, helpful, or fair. We predict that high scores on communal values and high scores on agentic traits are associated with life satisfaction. We test these predictions in two studies conducted in different countries (Germany and Russia with different cultural background. The findings support our reasoning: Across both countries we find positive associations of communal values and agentic traits with life satisfaction; and individuals high in communal values and high in agentic traits are most satisfied with their lives. In Russia, the association of communal values with life satisfaction is moderated by agentic traits; in Germany, however, there is a main effect of communal values.

  2. Identification of Non-Stationary Magnetic Field Sources Using the Matching Pursuit Method

    Directory of Open Access Journals (Sweden)

    Beata Palczynska

    2017-05-01

    Full Text Available The measurements of electromagnetic field emissions, performed on board a vessel have showed that, in this specific environment, a high level of non-stationary magnetic fields (MFs is observed. The adaptive time-frequency method can be used successfully to analyze this type of measured signal. It allows one to specify the time interval in which the individual frequency components of the signal occur. In this paper, the method of identification of non-stationary MF sources based on the matching pursuit (MP algorithm is presented. It consists of the decomposition of an examined time-waveform into the linear expansion of chirplet atoms and the analysis of the matrix of their parameters. The main feature of the proposed method is the modification of the chirplet’s matrix in a way that atoms, whose normalized energies are lower than a certain threshold, will be rejected. On the time-frequency planes of the spectrograms, obtained separately for each remaining chirlpet, it can clearly identify the time-frequency structures appearing in the examined signal. The choice of a threshold defines the computing speed and precision of the performed analysis. The method was implemented in the virtual application and used for processing real data, obtained from measurements of time-vary MF emissions onboard a ship.

  3. The Pursuit of Quantum Gravity Memoirs of Bryce DeWitt from 1946 to 2004

    CERN Document Server

    DeWitt-Morette, Cécile

    2011-01-01

    1946 is the year Bryce DeWitt entered Harvard graduate school. Quantum Gravity was his goal and remained his goal throughout his lifetime until the very end. The pursuit of Quantum Gravity requires a profound understanding of Quantum Physics and Gravitation Physics. As G. A. Vilkovisky commented , "Quantum Gravity is a combination of two words, and one should know both. Bryce understood this as nobody else, and this wisdom is completely unknown to many authors of the flux of papers that we see nowadays." Distingished physicist Cecile DeWitt-Morette skillfully blends her personal and scientific account with a wealth of her late husband's often unpublished writings on the subject matter. This volume, through the perspective of the leading researcher on quantum gravity of his generation, will provide an invaluable source of reference for anyone working in the field. "I found the book both instructive and fascinating. Bryce DeWitt and Cécile DeWitt-Morette formed the most creative couple in physics that I have e...

  4. Lamb wave based automatic damage detection using matching pursuit and machine learning

    International Nuclear Information System (INIS)

    Agarwal, Sushant; Mitra, Mira

    2014-01-01

    In this study, matching pursuit (MP) has been tested with machine learning algorithms such as artificial neural networks (ANNs) and support vector machines (SVMs) to automate the process of damage detection in metallic plates. Here, damage detection is done using the Lamb wave response in a thin aluminium plate simulated using a finite element (FE) method. To reduce the complexity of the Lamb wave response, only the A 0 mode is excited and sensed. The procedure adopted for damage detection consists of three major steps, involving signal processing and machine learning (ML). In the first step, MP is used for de-noising and enhancing the sparsity of the database. In the existing literature, MP is used to decompose any signal into a linear combination of waveforms that are selected from a redundant dictionary. In this work, MP is deployed in two stages to make the database sparse as well as to de-noise it. After using MP on the database, it is then passed as input data for ML classifiers. ANN and SVM are used to detect the location of the potential damage from the reduced data. The study demonstrates that the SVM is a robust classifier in the presence of noise and is more efficient than the ANN. Out-of-sample data are used for the validation of the trained and tested classifier. Trained classifiers are found to be successful in the detection of damage with a detection rate of more than 95%. (paper)

  5. The pursuit of longevity - the bringer of peace to the middle East.

    Science.gov (United States)

    Stambler, Ilia

    2014-01-01

    Despite the common apprehensions regarding the aging population, this work aims to argue, on both deontological and utilitarian moral grounds, that any increase in general life-expectancy will be beneficial for the Middle East, countering the common fears associated with this increase. A set of ethical arguments concerning increasing longevity is presented, from both the deontological and utilitarian perspective. A wide selection of economic, psychological, demographic and epidemiological literature and databases is analyzed to determine common correlates of extended longevity. On the deontological grounds, the value of extended longevity is derived from the value of life preservation, regardless of its term. On the utilitarian grounds, the value of extended longevity is demonstrated by its correlation with further human values, such as education level and intellectual activity, economic prosperity, equality, solidarity and peacefulness. With the common apprehensions of stagnation and scarcity due to life extension found wanting, the pursuit of longevity by the population can be seen as a cross-cultural and cross-generational good. Though the current study mainly refers to sources and data relevant to the Middle East, a similar pro-longevity argument can be also made for other cultural contexts. In view of its numerous benefits, normatively, the goal of longevity should be set clearly and openly by the society, and actively pursued, or at least discussed, in academia, the political system and broader public.

  6. Waveguide damage detection by the matching pursuit approach employing the dispersion-based chirp functions.

    Science.gov (United States)

    Hong, Jin-Chul; Sun, Kyung Ho; Kim, Yoon Young

    2006-03-01

    If the wave mode used in guided wave non-destructive inspection is dispersive, reflected pulses from damaged parts may be significantly distorted due to wave dispersion. The main concern, in this case, is how to detect the reflected pulses in noisy signals, and to extract meaningful damage information from the detected pulses. However, current signal processing techniques used for guided wave inspection do not account for pulse dispersion, so the extracted information is often not so accurate. The objective of this study is to develop an efficient technique to deal with dispersed pulses for guided-wave nondestructive evaluation. Our idea is to model dispersed pulses by chirp functions of special form that can simulate up to quadratically varying group delay. To determine the parameters of the chirp functions approximating dispersed, reflected pulses, an adaptive matching pursuit algorithm is employed. Once the characterizing parameters are found, the damage location and extent can be estimated. The proposed method is tested with experimentally measured signals of longitudinal waves in a circular cylinder.

  7. The Pursuit of Happiness Measurement: A Psychometric Model Based on Psychophysiological Correlates

    Science.gov (United States)

    Pietro, Cipresso; Silvia, Serino; Giuseppe, Riva

    2014-01-01

    Everyone is interested in the pursuit of happiness, but the real problem for the researchers is how to measure it. Our aim was to deeply investigate happiness measurement through biomedical signals, using psychophysiological methods to objectify the happiness experiences measurements. The classic valence-arousal model of affective states to study happiness has been extensively used in psychophysiology. However, really few studies considered a real combination of these two dimensions and no study further investigated multidimensional models. More, most studies focused mainly on self-report to measure happiness and a deeper psychophysiological investigation on the dimensions of such an experience is still missing. A multidimensional model of happiness is presented and both the dimensions and the measures extracted within each dimension are comprehensively explained. This multidimensional model aims at being a milestone for future systematic study on psychophysiology of happiness and affective states. It seems everyone has a view on happiness. Joan Collins, theDalai Lama and over 100 others have released new titles on the subject since the beginning of 2001 Richard Tooth “The Psychology of Happiness (2nd Edition)”Michael Argyle, Routledge PMID:24955383

  8. A pursuit of significance of the coarsened gastric rugae in radiologic examination

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ok Dong [Chung Ang University College of Medicine, Seoul (Korea, Republic of)

    1979-06-15

    The radiologic upper G.I. series and gastroscopic examination with gastric biopsies of 230 cases were carried out in Korea General Hospital for the purpose of pursuit of significance of coarsened gastric rugae. Out of the above series the 26 cases showing mere radiologic finding of coarsening of the gastric mucosal rugae were selected, excluding the cases with definite evidence of ulceration, malignancies and others. The correlativity of the coarsened gastric rugae was investigated with clinical pictures, gastroscopic features and biopsy findings. The following results were obtained: 1. There were 24 cases of gastritis, 5 of stomach ulcer and 2 of stomach cancer in the 26 cases with mere finding of mucosal coarsening. 2. There was 5 cases of stomach ulcer disease revealing no radiologic evidence, but there were found tiny ulcers in 4 cases and a large ulcer crater of 1.0 cm by 1.5 cm in diameter in the other case under the gastroscopic study. 3. Two cases of stomach cancer were not detected in neither radiologic nor gastroscopic examination, however, they were found by gastric biopsy. 4. It should be strongly emphasized that the biopsy under the gastroscopic control must be followed when a radiologic evidence of coarsened gastric rugae is demonstrated.

  9. A pursuit of significance of the coarsened gastric rugae in radiologic examination

    International Nuclear Information System (INIS)

    Kim, Ok Dong

    1979-01-01

    The radiologic upper G.I. series and gastroscopic examination with gastric biopsies of 230 cases were carried out in Korea General Hospital for the purpose of pursuit of significance of coarsened gastric rugae. Out of the above series the 26 cases showing mere radiologic finding of coarsening of the gastric mucosal rugae were selected, excluding the cases with definite evidence of ulceration, malignancies and others. The correlativity of the coarsened gastric rugae was investigated with clinical pictures, gastroscopic features and biopsy findings. The following results were obtained: 1. There were 24 cases of gastritis, 5 of stomach ulcer and 2 of stomach cancer in the 26 cases with mere finding of mucosal coarsening. 2. There was 5 cases of stomach ulcer disease revealing no radiologic evidence, but there were found tiny ulcers in 4 cases and a large ulcer crater of 1.0 cm by 1.5 cm in diameter in the other case under the gastroscopic study. 3. Two cases of stomach cancer were not detected in neither radiologic nor gastroscopic examination, however, they were found by gastric biopsy. 4. It should be strongly emphasized that the biopsy under the gastroscopic control must be followed when a radiologic evidence of coarsened gastric rugae is demonstrated.

  10. Succession of hide-seek and pursuit-evasion at heterogeneous locations.

    Science.gov (United States)

    Gal, Shmuel; Casas, Jérôme

    2014-05-06

    Many interactions between searching agents and their elusive targets are composed of a succession of steps, whether in the context of immune systems, predation or counterterrorism. In the simplest case, a two-step process starts with a search-and-hide phase, also called a hide-and-seek phase, followed by a round of pursuit-escape. Our aim is to link these two processes, usually analysed separately and with different models, in a single game theory context. We define a matrix game in which a searcher looks at a fixed number of discrete locations only once each searching for a hider, which can escape with varying probabilities according to its location. The value of the game is the overall probability of capture after k looks. The optimal search and hide strategies are described. If a searcher looks only once into any of the locations, an optimal hider chooses it's hiding place so as to make all locations equally attractive. This optimal strategy remains true as long as the number of looks is below an easily calculated threshold; however, above this threshold, the optimal position for the hider is where it has the highest probability of escaping once spotted.

  11. Composite Plate Phased Array Structural Health Monitoring Signal Reconstruction Based on Orthogonal Matching Pursuit Algorithm

    Directory of Open Access Journals (Sweden)

    Yajie Sun

    2017-01-01

    Full Text Available In order to ensure the safety of composite components, structural health monitoring is needed to detect structural performance in real-time at the early stage of damage occurred. This is difficult to detect complex components with single sensor detection technology, so that ultrasonic phased array technology using multisensor detection will be selected. Ultrasonic phased array technology can scan the structure in all directions and angles without moving or less moving the probe and becomes the first choice of structural health monitoring. However, a large amount of data will be generated when using ultrasonic phased array with Nyquist sampling theorem for structural health monitoring and is difficult to storage, transmission, and processing. Besides, traditional Nyquist sampling cannot satisfy the sampling of large amounts of data without distortion, so a more efficient acquisition technique must be chosen. Compressive sensing theory can ensure that if the signal is sparse, it can be sampled in low sampling rate which is much less than two times of the sampling rate as defined by Nyquist sampling theorem for a large number of data and reconstructed in high probability. Then, the experiment result indicated that the orthogonal matching pursuit algorithm can reconstruct the signal completely and accurately.

  12. Beta Hebbian Learning as a New Method for Exploratory Projection Pursuit.

    Science.gov (United States)

    Quintián, Héctor; Corchado, Emilio

    2017-09-01

    In this research, a novel family of learning rules called Beta Hebbian Learning (BHL) is thoroughly investigated to extract information from high-dimensional datasets by projecting the data onto low-dimensional (typically two dimensional) subspaces, improving the existing exploratory methods by providing a clear representation of data's internal structure. BHL applies a family of learning rules derived from the Probability Density Function (PDF) of the residual based on the beta distribution. This family of rules may be called Hebbian in that all use a simple multiplication of the output of the neural network with some function of the residuals after feedback. The derived learning rules can be linked to an adaptive form of Exploratory Projection Pursuit and with artificial distributions, the networks perform as the theory suggests they should: the use of different learning rules derived from different PDFs allows the identification of "interesting" dimensions (as far from the Gaussian distribution as possible) in high-dimensional datasets. This novel algorithm, BHL, has been tested over seven artificial datasets to study the behavior of BHL parameters, and was later applied successfully over four real datasets, comparing its results, in terms of performance, with other well-known Exploratory and projection models such as Maximum Likelihood Hebbian Learning (MLHL), Locally-Linear Embedding (LLE), Curvilinear Component Analysis (CCA), Isomap and Neural Principal Component Analysis (Neural PCA).

  13. RMP: Reduced-set matching pursuit approach for efficient compressed sensing signal reconstruction

    Directory of Open Access Journals (Sweden)

    Michael M. Abdel-Sayed

    2016-11-01

    Full Text Available Compressed sensing enables the acquisition of sparse signals at a rate that is much lower than the Nyquist rate. Compressed sensing initially adopted ℓ1 minimization for signal reconstruction which is computationally expensive. Several greedy recovery algorithms have been recently proposed for signal reconstruction at a lower computational complexity compared to the optimal ℓ1 minimization, while maintaining a good reconstruction accuracy. In this paper, the Reduced-set Matching Pursuit (RMP greedy recovery algorithm is proposed for compressed sensing. Unlike existing approaches which either select too many or too few values per iteration, RMP aims at selecting the most sufficient number of correlation values per iteration, which improves both the reconstruction time and error. Furthermore, RMP prunes the estimated signal, and hence, excludes the incorrectly selected values. The RMP algorithm achieves a higher reconstruction accuracy at a significantly low computational complexity compared to existing greedy recovery algorithms. It is even superior to ℓ1 minimization in terms of the normalized time-error product, a new metric introduced to measure the trade-off between the reconstruction time and error. RMP superior performance is illustrated with both noiseless and noisy samples.

  14. Spanning boundaries in pursuit of effective knowledge sharing within networks in the NHS.

    Science.gov (United States)

    Currie, Graeme; Finn, Rachael; Martin, Graham

    2007-01-01

    The purpose of this paper is to examine power asymmetries in the delivery of genetics healthcare that inhibit knowledge sharing across sector, organisational and professional boundaries. The paper is a longitudinal comparative case study approach, which encompasses semi-structured interviews and observation. The paper finds politics to be significant in its influence on knowledge sharing across sector, organisational and professional boundaries, but this can be mediated by attending to human and social aspects of the context in which knowledge sharing was expected to take place. The paper encourages research that evaluates the effect of increased emphasis on human and social aspects of organisational change in pursuit of the "dream" of spanning boundaries and improving knowledge sharing within the NHS. The paper shows that structural change appears to be of limited effect in promoting knowledge sharing. Organisational and individual development, career management and performance systems are worthy of attention for the purpose of managing knowledge. The paper exposes this assumption as managerialist. Policy-makers assume that professionals are willing and able to share knowledge when delivering healthcare through networks.

  15. An Analysis and Application of Fast Nonnegative Orthogonal Matching Pursuit for Image Categorization in Deep Networks

    Directory of Open Access Journals (Sweden)

    Bo Wang

    2015-01-01

    Full Text Available Nonnegative orthogonal matching pursuit (NOMP has been proven to be a more stable encoder for unsupervised sparse representation learning. However, previous research has shown that NOMP is suboptimal in terms of computational cost, as the coefficients selection and refinement using nonnegative least squares (NNLS have been divided into two separate steps. It is found that this problem severely reduces the efficiency of encoding for large-scale image patches. In this work, we study fast nonnegative OMP (FNOMP as an efficient encoder which can be accelerated by the implementation of QR factorization and iterations of coefficients in deep networks for full-size image categorization task. It is analyzed and demonstrated that using relatively simple gain-shape vector quantization for training dictionary, FNOMP not only performs more efficiently than NOMP for encoding but also significantly improves the classification accuracy compared to OMP based algorithm. In addition, FNOMP based algorithm is superior to other state-of-the-art methods on several publicly available benchmarks, that is, Oxford Flowers, UIUC-Sports, and Caltech101.

  16. Pursuit of communal values in an agentic manner: a way to happiness?

    Science.gov (United States)

    Abele, Andrea E.

    2014-01-01

    The present research studies the association between traits, values, and life satisfaction. While values should influence the direction of an individual’s goals and behavior, his/her traits impact effort-expenditure, efficiency, and persistence in goal-pursuit. We apply the framework of the “Big Two” of agency and communion (Bakan, 1966) for distinguishing the content of values and traits. While agentic content refers to qualities relevant for goal-attainment, such as assertiveness, competence or persistence, communal content refers to qualities relevant for the establishment and maintenance of social relationships, such as being friendly, helpful, or fair. We predict that high scores on communal values and high scores on agentic traits are associated with life satisfaction. We test these predictions in two studies conducted in different countries (Germany and Russia) with different cultural background. The findings support our reasoning: across both countries we find positive associations of communal values and agentic traits with life satisfaction; and individuals high in communal values and high in agentic traits are most satisfied with their lives. In Russia, the association of communal values with life satisfaction is moderated by agentic traits; in Germany, however, there is a main effect of communal values. PMID:25477843

  17. Sparsely corrupted stimulated scattering signals recovery by iterative reweighted continuous basis pursuit

    International Nuclear Information System (INIS)

    Wang, Kunpeng; Chai, Yi; Su, Chunxiao

    2013-01-01

    In this paper, we consider the problem of extracting the desired signals from noisy measurements. This is a classical problem of signal recovery which is of paramount importance in inertial confinement fusion. To accomplish this task, we develop a tractable algorithm based on continuous basis pursuit and reweighted ℓ 1 -minimization. By modeling the observed signals as superposition of scale time-shifted copies of theoretical waveform, structured noise, and unstructured noise on a finite time interval, a sparse optimization problem is obtained. We propose to solve this problem through an iterative procedure that alternates between convex optimization to estimate the amplitude, and local optimization to estimate the dictionary. The performance of the method was evaluated both numerically and experimentally. Numerically, we recovered theoretical signals embedded in increasing amounts of unstructured noise and compared the results with those obtained through popular denoising methods. We also applied the proposed method to a set of actual experimental data acquired from the Shenguang-II laser whose energy was below the detector noise-equivalent energy. Both simulation and experiments show that the proposed method improves the signal recovery performance and extends the dynamic detection range of detectors

  18. Orthogonal Matching Pursuit for Enhanced Recovery of Sparse Geological Structures With the Ensemble Kalman Filter

    KAUST Repository

    Sana, Furrukh

    2016-02-23

    Estimating the locations and the structures of subsurface channels holds significant importance for forecasting the subsurface flow and reservoir productivity. These channels exhibit high permeability and are easily contrasted from the low-permeability rock formations in their surroundings. This enables formulating the flow channels estimation problem as a sparse field recovery problem. The ensemble Kalman filter (EnKF) is a widely used technique for the estimation and calibration of subsurface reservoir model parameters, such as permeability. However, the conventional EnKF framework does not provide an efficient mechanism to incorporate prior information on the wide varieties of subsurface geological structures, and often fails to recover and preserve flow channel structures. Recent works in the area of compressed sensing (CS) have shown that estimating in a sparse domain, using algorithms such as the orthogonal matching pursuit (OMP), may significantly improve the estimation quality when dealing with such problems. We propose two new, and computationally efficient, algorithms combining OMP with the EnKF to improve the estimation and recovery of the subsurface geological channels. Numerical experiments suggest that the proposed algorithms provide efficient mechanisms to incorporate and preserve structural information in the EnKF and result in significant improvements in recovering flow channel structures.

  19. TH-D-204-00: The Pursuit of Radiation Oncology Performance Excellence

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    The Malcolm Baldrige National Quality Improvement Act was signed into law in 1987 to advance U.S. business competitiveness and economic growth. Administered by the National Institute of Standards and Technology NIST, the Act created the Baldrige National Quality Program, now renamed the Baldrige Performance Excellence Program. The comprehensive analytical approaches referred to as the Baldrige Healthcare Criteria, are very well suited for the evaluation and sustainable improvement of radiation oncology management and operations. A multidisciplinary self-assessment approach is used for radiotherapy program evaluation and development in order to generate a fact based knowledge driven system for improving quality of care, increasing patient satisfaction, building employee engagement, and boosting organizational innovation. The methodology also provides a valuable framework for benchmarking an individual radiation oncology practice against guidelines defined by accreditation and professional organizations and regulatory agencies. Learning Objectives: To gain knowledge of the Baldrige Performance Excellence Program as it relates to Radiation Oncology. To appreciate the value of a multidisciplinary self-assessment approach in the pursuit of Radiation Oncology quality care, patient satisfaction, and workforce commitment. To acquire a set of useful measurement tools with which an individual Radiation Oncology practice can benchmark its performance against guidelines defined by accreditation and professional organizations and regulatory agencies.

  20. TH-D-204-00: The Pursuit of Radiation Oncology Performance Excellence

    International Nuclear Information System (INIS)

    2016-01-01

    The Malcolm Baldrige National Quality Improvement Act was signed into law in 1987 to advance U.S. business competitiveness and economic growth. Administered by the National Institute of Standards and Technology NIST, the Act created the Baldrige National Quality Program, now renamed the Baldrige Performance Excellence Program. The comprehensive analytical approaches referred to as the Baldrige Healthcare Criteria, are very well suited for the evaluation and sustainable improvement of radiation oncology management and operations. A multidisciplinary self-assessment approach is used for radiotherapy program evaluation and development in order to generate a fact based knowledge driven system for improving quality of care, increasing patient satisfaction, building employee engagement, and boosting organizational innovation. The methodology also provides a valuable framework for benchmarking an individual radiation oncology practice against guidelines defined by accreditation and professional organizations and regulatory agencies. Learning Objectives: To gain knowledge of the Baldrige Performance Excellence Program as it relates to Radiation Oncology. To appreciate the value of a multidisciplinary self-assessment approach in the pursuit of Radiation Oncology quality care, patient satisfaction, and workforce commitment. To acquire a set of useful measurement tools with which an individual Radiation Oncology practice can benchmark its performance against guidelines defined by accreditation and professional organizations and regulatory agencies.

  1. TH-D-204-01: The Pursuit of Radiation Oncology Performance Excellence

    Energy Technology Data Exchange (ETDEWEB)

    Sternick, E. [The Warren Alpert Medical School of Brown Univ., Providence, RI (United States)

    2016-06-15

    The Malcolm Baldrige National Quality Improvement Act was signed into law in 1987 to advance U.S. business competitiveness and economic growth. Administered by the National Institute of Standards and Technology NIST, the Act created the Baldrige National Quality Program, now renamed the Baldrige Performance Excellence Program. The comprehensive analytical approaches referred to as the Baldrige Healthcare Criteria, are very well suited for the evaluation and sustainable improvement of radiation oncology management and operations. A multidisciplinary self-assessment approach is used for radiotherapy program evaluation and development in order to generate a fact based knowledge driven system for improving quality of care, increasing patient satisfaction, building employee engagement, and boosting organizational innovation. The methodology also provides a valuable framework for benchmarking an individual radiation oncology practice against guidelines defined by accreditation and professional organizations and regulatory agencies. Learning Objectives: To gain knowledge of the Baldrige Performance Excellence Program as it relates to Radiation Oncology. To appreciate the value of a multidisciplinary self-assessment approach in the pursuit of Radiation Oncology quality care, patient satisfaction, and workforce commitment. To acquire a set of useful measurement tools with which an individual Radiation Oncology practice can benchmark its performance against guidelines defined by accreditation and professional organizations and regulatory agencies.

  2. TH-D-204-01: The Pursuit of Radiation Oncology Performance Excellence

    International Nuclear Information System (INIS)

    Sternick, E.

    2016-01-01

    The Malcolm Baldrige National Quality Improvement Act was signed into law in 1987 to advance U.S. business competitiveness and economic growth. Administered by the National Institute of Standards and Technology NIST, the Act created the Baldrige National Quality Program, now renamed the Baldrige Performance Excellence Program. The comprehensive analytical approaches referred to as the Baldrige Healthcare Criteria, are very well suited for the evaluation and sustainable improvement of radiation oncology management and operations. A multidisciplinary self-assessment approach is used for radiotherapy program evaluation and development in order to generate a fact based knowledge driven system for improving quality of care, increasing patient satisfaction, building employee engagement, and boosting organizational innovation. The methodology also provides a valuable framework for benchmarking an individual radiation oncology practice against guidelines defined by accreditation and professional organizations and regulatory agencies. Learning Objectives: To gain knowledge of the Baldrige Performance Excellence Program as it relates to Radiation Oncology. To appreciate the value of a multidisciplinary self-assessment approach in the pursuit of Radiation Oncology quality care, patient satisfaction, and workforce commitment. To acquire a set of useful measurement tools with which an individual Radiation Oncology practice can benchmark its performance against guidelines defined by accreditation and professional organizations and regulatory agencies.

  3. An orbital emulator for pursuit-evasion game theoretic sensor management

    Science.gov (United States)

    Shen, Dan; Wang, Tao; Wang, Gang; Jia, Bin; Wang, Zhonghai; Chen, Genshe; Blasch, Erik; Pham, Khanh

    2017-05-01

    This paper develops and evaluates an orbital emulator (OE) for space situational awareness (SSA). The OE can produce 3D satellite movements using capabilities generated from omni-wheeled robot and robotic arm motion methods. The 3D motion of a satellite is partitioned into the movements in the equatorial plane and the up-down motions in the vertical plane. The 3D actions are emulated by omni-wheeled robot models while the up-down motions are performed by a stepped-motor-controlled-ball along a rod (robotic arm), which is attached to the robot. For multiple satellites, a fast map-merging algorithm is integrated into the robot operating system (ROS) and simultaneous localization and mapping (SLAM) routines to locate the multiple robots in the scene. The OE is used to demonstrate a pursuit-evasion (PE) game theoretic sensor management algorithm, which models conflicts between a space-based-visible (SBV) satellite (as pursuer) and a geosynchronous (GEO) satellite (as evader). The cost function of the PE game is based on the informational entropy of the SBV-tracking-GEO scenario. GEO can maneuver using a continuous and low thruster. The hard-in-loop space emulator visually illustrates the SSA problem solution based PE game.

  4. Chain rules for smooth min-and max-entropies

    DEFF Research Database (Denmark)

    Vitanov, Alexande; Dupont-Dupuis, Fréderic; Tomamichel, Marco

    2013-01-01

    The chain rule for the Shannon and von Neumann en- tropy, which relates the total entropy of a system to the entropies of its parts, is of central importance to information theory. Here, we consider the chain rule for the more general smooth min- and max-entropies, used in one-shot in formation...... theory. For these en- tropy measures, the chain rule no longer holds as an equality. How- ever, the standard chain rule for the von Neum ann entropy is re- trieved asymptotically when evaluating the smooth entropies for many identical and independently distributed states....

  5. The smooth entropy formalism for von Neumann algebras

    International Nuclear Information System (INIS)

    Berta, Mario; Furrer, Fabian; Scholz, Volkher B.

    2016-01-01

    We discuss information-theoretic concepts on infinite-dimensional quantum systems. In particular, we lift the smooth entropy formalism as introduced by Renner and collaborators for finite-dimensional systems to von Neumann algebras. For the smooth conditional min- and max-entropy, we recover similar characterizing properties and information-theoretic operational interpretations as in the finite-dimensional case. We generalize the entropic uncertainty relation with quantum side information of Tomamichel and Renner and discuss applications to quantum cryptography. In particular, we prove the possibility to perform privacy amplification and classical data compression with quantum side information modeled by a von Neumann algebra

  6. Implementation of mobile ip smooth handoff in wireless networks

    International Nuclear Information System (INIS)

    Kayastha, M.; Chowdhry, B.S.; Memon, A.R.

    2002-01-01

    This paper describes implementation of mobile IP services in two separate wireless LANs based on IEEE 802.11b standards, located in two distant buildings of a university campus. The purpose of the project was to achieve smooth hand-off when a mobile node moves between the two LANs. During our experimentation we have identified some of the limitation of IEEE 802.11b that affects mobile 1P smooth hand off. We have also proposed an algorithm to solve this problem when the mobility is within a limited number of separate wireless LANs. (author)

  7. Peaked and Smooth Solitons for K*(4,1 Equation

    Directory of Open Access Journals (Sweden)

    Yongan Xie

    2013-01-01

    Full Text Available This paper is contributed to explore all possible single peak solutions for the K*(4,1 equation ut=uxu2+2α(uuxxx+2uxuxx. Our procedure shows that the K*(4,1 equation either has peakon, cuspon, and smooth soliton solutions when sitting on a nonzero constant pedestal limξ→±∞u=A≠0 or possesses compacton solutions only when limξ→±∞u=A=0. We present a new smooth soliton solution in an explicit form. Mathematical analysis and numeric graphs are provided for those soliton solutions of the K*(4,1 equation.

  8. The smooth entropy formalism for von Neumann algebras

    Energy Technology Data Exchange (ETDEWEB)

    Berta, Mario, E-mail: berta@caltech.edu [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125 (United States); Furrer, Fabian, E-mail: furrer@eve.phys.s.u-tokyo.ac.jp [Department of Physics, Graduate School of Science, University of Tokyo, Tokyo, Japan and Institute for Theoretical Physics, Leibniz University Hanover, Hanover (Germany); Scholz, Volkher B., E-mail: scholz@phys.ethz.ch [Institute for Theoretical Physics, ETH Zurich, Zurich (Switzerland)

    2016-01-15

    We discuss information-theoretic concepts on infinite-dimensional quantum systems. In particular, we lift the smooth entropy formalism as introduced by Renner and collaborators for finite-dimensional systems to von Neumann algebras. For the smooth conditional min- and max-entropy, we recover similar characterizing properties and information-theoretic operational interpretations as in the finite-dimensional case. We generalize the entropic uncertainty relation with quantum side information of Tomamichel and Renner and discuss applications to quantum cryptography. In particular, we prove the possibility to perform privacy amplification and classical data compression with quantum side information modeled by a von Neumann algebra.

  9. A Non-smooth Newton Method for Multibody Dynamics

    International Nuclear Information System (INIS)

    Erleben, K.; Ortiz, R.

    2008-01-01

    In this paper we deal with the simulation of rigid bodies. Rigid body dynamics have become very important for simulating rigid body motion in interactive applications, such as computer games or virtual reality. We present a novel way of computing contact forces using a Newton method. The contact problem is reformulated as a system of non-linear and non-smooth equations, and we solve this system using a non-smooth version of Newton's method. One of the main contribution of this paper is the reformulation of the complementarity problems, used to model impacts, as a system of equations that can be solved using traditional methods.

  10. Cytotoxic actions of palytoxin on aortic smooth muscle cells in culture.

    Science.gov (United States)

    Sheridan, Robert E; Deshpande, Sharad S; Adler, Michael

    2005-01-01

    Palytoxin (PTX), isolated from a zoanthid of the genus Palythoa, is the most potent marine toxin known. Intoxication by PTX leads to vasoconstriction, hemorrhage, ataxia, muscle weakness, ventricular fibrillation, pulmonary hypertension, ischemia and death. In this study, clonal A7r5 rat aortic smooth muscle cells were used to study the mechanism of PTX-mediated cytotoxicity. A7r5 cells exposed to PTX for > or = 15 min exhibited surface granularities, vacuoles and rounding. These alterations culminated in a loss of viability as indicated by marked increases in the release of lactate dehydrogenase. Electrophysiological recording from A7r5 cells disclosed a profound membrane depolarization and an increase in conductance to Na+ and K+. PTX-mediated cytotoxicity could not be reversed by washout or by the addition of 10 microM verapamil but was antagonized by 100 microM ouabain or by removal of extracellular Na+ or Ca2+. In light of the involvement of vascular smooth muscle in PTX poisoning, A7r5 cells could serve as a useful model to test specific drugs for treatment of PTX intoxication. 2005 John Wiley & Sons, Ltd.

  11. Partially to fully saturated flow through smooth, clean, open fractures: qualitative experimental studies

    Science.gov (United States)

    Jones, Brendon R.; Brouwers, Luke B.; Dippenaar, Matthys A.

    2018-05-01

    Fractures are both rough and irregular but can be expressed by a simple model concept of two smooth parallel plates and the associated cubic law governing discharge through saturated fractures. However, in natural conditions and in the intermediate vadose zone, these assumptions are likely violated. This paper presents a qualitative experimental study investigating the cubic law under variable saturation in initially dry free-draining discrete fractures. The study comprised flow visualisation experiments conducted on transparent replicas of smooth parallel plates with inlet conditions of constant pressure and differing flow rates over both vertical and horizontal inclination. Flow conditions were altered to investigate the influence of intermittent and continuous influx scenarios. Findings from this research proved, for instance, that saturated laminar flow is not likely achieved, especially in nonhorizontal fractures. In vertical fractures, preferential flow occupies the minority of cross-sectional area despite the water supply. Movement of water through the fractured vadose zone therefore becomes a matter of the continuity principle, whereby water should theoretically be transported downward at significantly higher flow rates given the very low degree of water saturation. Current techniques that aim to quantify discrete fracture flow, notably at partial saturation, are questionable. Inspired by the results of this study, it is therefore hypothetically improbable to achieve saturation in vertical fractures under free-draining wetting conditions. It does become possible under extremely excessive water inflows or when not free-draining; however, the converse is not true, as a wet vertical fracture can be drained.

  12. Effect of phototherapy on gastrointestinal smooth muscle activity and oxidative stress.

    Science.gov (United States)

    Soyer, Tutku; Aliefendioğlu, Didem; Aktuna, Zuhal; Cağlayan, Osman; Aydos, Tolga Reşat; Cakmak, Murat

    2011-11-01

    To evaluate the effect of phototherapy on gastrointestinal smooth muscle activity and oxidative stress. Wistar albino rats (n = 18, in the first 7 days of life) weighing 7 ± 2 g with both sexes were included in the study. The animals were randomized into three groups. In control group (CG), median laparotomy was performed to obtain 1 cm of jejunum, terminal ileum and colonic segments. In the phototherapy group (PTG), led phototherapy with a wave density of 40 μw/cm(2)/nm were used (Bilitron 3006, Fanem, Brasil). The efficacy surface of phototherapy was 30-40 cm and the exposure distance was 30 cm. The duration of phototherapy was 24 h. Sham group (SG) received white light with the same wave density and exposure distance. The oxidative stress markers and contraction responses were investigated from intestinal segments obtained from experiments. The jejunum segments showed significantly lowered contraction response to carbachol in SG when compared to CG and PTG (p 0.05). Total sulfhydryl (T-SH) levels were found significantly increased in PTG when compared to CG and SG (p < 0.05). When NO levels were evaluated, NO levels were found decreased in PTG and SG with respect to CG (p < 0.05). PT may cause various alterations in oxidant/antioxidant system in intestinal segments. Unlike to clinical findings, decreased contractile responses were detected in rat gastrointestinal smooth muscles after PT.

  13. Effects of alkaloids of Himatanthus lancifolius (Muell. Arg.) Woodson, Apocynaceae, on smooth muscle responsiveness.

    Science.gov (United States)

    Rattmann, Yanna D; Terluk, Márcia R; Souza, Wesley M; Santos, Cid A M; Biavatti, Maique W; Torres, Luce B; Mesia-Vela, Sonia; Rieck, Lia; da Silva-Santos, José E; Marques, Maria C de A

    2005-09-14

    Himatanthus lancifolius, popularly known as "agoniada" in Brazil, is largely used in folk medicine against asthma, dysmenorrhea and as an emenagogue and abortive. This study reveals the effects of an alkaloid rich fraction (AlkF) obtained from the bark of Himatanthus lancifolius in vascular and non-vascular smooth muscle responsiveness. Incubation of AlkF (3-30 microg/ml) during 15 min generates a concentration-related and fully reversible reduction in maximal contractile responses evoked by acetylcholine and phenylephrine in rat jejune and aorta preparations, respectively. Exposition of endothelium-denuded pre-contracted rat aorta rings to AlkF results in a complete relaxation, with EC(50) of 22.2 (16.2-28.2 microg/ml). AlkF is also able to induce a concentration-related rightward shift of cumulative concentration curves for calcium in uterus and aorta rings maintained in depolarizing nutritive solution. Moreover, addition of AlkF in calcium-free solution also reduces, in a concentration-dependent manner, the ability of caffeine and phenylephrine to contract aorta rings. This study reveals that the bark of Himatanthus lancifolius possesses one or more indole alkaloids able to alter non-vascular and vascular smooth muscle responsiveness, an event that may involve the blocking of calcium entry or changes on intracellular calcium utilization or mobilization.

  14. Partially to fully saturated flow through smooth, clean, open fractures: qualitative experimental studies

    Science.gov (United States)

    Jones, Brendon R.; Brouwers, Luke B.; Dippenaar, Matthys A.

    2017-11-01

    Fractures are both rough and irregular but can be expressed by a simple model concept of two smooth parallel plates and the associated cubic law governing discharge through saturated fractures. However, in natural conditions and in the intermediate vadose zone, these assumptions are likely violated. This paper presents a qualitative experimental study investigating the cubic law under variable saturation in initially dry free-draining discrete fractures. The study comprised flow visualisation experiments conducted on transparent replicas of smooth parallel plates with inlet conditions of constant pressure and differing flow rates over both vertical and horizontal inclination. Flow conditions were altered to investigate the influence of intermittent and continuous influx scenarios. Findings from this research proved, for instance, that saturated laminar flow is not likely achieved, especially in nonhorizontal fractures. In vertical fractures, preferential flow occupies the minority of cross-sectional area despite the water supply. Movement of water through the fractured vadose zone therefore becomes a matter of the continuity principle, whereby water should theoretically be transported downward at significantly higher flow rates given the very low degree of water saturation. Current techniques that aim to quantify discrete fracture flow, notably at partial saturation, are questionable. Inspired by the results of this study, it is therefore hypothetically improbable to achieve saturation in vertical fractures under free-draining wetting conditions. It does become possible under extremely excessive water inflows or when not free-draining; however, the converse is not true, as a wet vertical fracture can be drained.

  15. The Controversy Behind the Air Corps Tactical School's Strategic Bombardment Theory: An Analysis of the Bombardment Versus Pursuit Aviation Data Between 1930-1939

    National Research Council Canada - National Science Library

    Severs, Hugh

    1997-01-01

    ... at the expense of pursuit aviation. The report used primary source data from the Air Force Historical Research Agency and various secondary sources to analyze results of Air Corps training exercises and combat data from overseas conflicts...

  16. Stable schizophrenia patients learn equally well as age-matched controls and better than elderly controls in two sensorimotor Rotary Pursuit tasks

    Directory of Open Access Journals (Sweden)

    Livia J. De Picker

    2014-11-01

    Full Text Available Objective: To compare sensorimotor performance and learning in stable schizophrenia patients, healthy age- and sex-matched controls and elderly controls on two variations of the Rotary Pursuit: Circle Pursuit (true motor learning and Figure Pursuit (motor and sequence learning.Method: In the Circle Pursuit a target circle, rotating with increasing speed along a predictable circular path on the computer screen, must be followed by a cursor controlled by a pen on a writing tablet. In the eight-trial Figure Pursuit, subjects learn to draw a complex figure by pursuing the target circle that moves along an invisible trajectory between and around several goals. Tasks were administered thrice (day 1, day 2, day 7 to 30 patients with stable schizophrenia (S, 30 healthy age- and sex-matched controls (C and 30 elderly participants (>65y; E and recorded with a digitizing tablet and pressure-sensitive pen. The outcome measure accuracy (% of time that cursor is within the target was used to assess performance.Results: We observed significant group differences in accuracy, both in Circle and Figure Pursuit tasks (EPursuit but differed between groups in Figure Pursuit. When corrected for group differences in starting level, the learning gains over the three sessions of schizophrenia patients and age-matched controls were equal and both were larger than those of the elderly controls. Conclusion: Despite the reduced sensorimotor performance that was found in the schizophrenia patients their sensorimotor learning seems to be preserved. The relevance of this finding for the evaluation of procedural learning in schizophrenia is discussed. The better performance and learning rate of the patients compared to the elderly controls was unexpected and deserves further study.

  17. Reactive oxygen species are involved in regulating α1-adrenoceptor-activated vascular smooth muscle contraction

    Directory of Open Access Journals (Sweden)

    Tsai Ming-Ho

    2010-08-01

    Full Text Available Abstract Background Reactive oxygen species (ROS were shown to mediate aberrant contractility in hypertension, yet the physiological roles of ROS in vascular smooth muscle contraction have remained elusive. This study aimed to examine whether ROS regulate α1-adrenoceptor-activated contraction by altering myosin phosphatase activities. Methods Using endothelium-denuded rat tail artery (RTA strips, effects of anti-oxidants on isometric force, ROS production, phosphorylation of the 20-kDa myosin light chain (MLC20, and myosin phosphatase stimulated by α1-adrenoceptor agonist phenylephrine were examined. Results An antioxidant, N-acetyl-L-cysteine (NAC, and two NADPH oxidase inhibitors, apocynin and VAS2870, dose-dependently inhibited contraction activated by phenylephrine. Phenylephrine stimulated superoxide anion production that was diminished by the pretreatment of apocynin, VAS2870, superoxide scavenger tiron or mitochondria inhibitor rotenone, but not by xanthine oxidase inhibitor allopurinol or cyclooxygenase inhibitor indomethacin. Concurrently, NADPH oxidase activity in RTA homogenates increased within 1 min upon phenylephrine stimulation, sustained for 10 min, and was abolished by the co-treatment with apocynin, but not allopurinol or rotenone. Phenylephrine-induced MLC20 phosphorylation was dose-dependently decreased by apocynin. Furthermore, apocynin inhibited phenylephrine-stimulated RhoA translocation to plasma membrane and phosphorylation of both myosin phosphatase regulatory subunit MYPT1Thr855 and myosin phosphatase inhibitor CPI-17Thr38. Conclusions ROS, probably derived from NADPH oxidase and mitochondria, partially regulate α1-adrenoceptor-activated smooth muscle contraction by altering myosin phosphatase-mediated MLC20 phosphorylation through both RhoA/Rho kinase- and CPI-17-dependent pathways.

  18. Biomechanical effects of environmental and engineered particles on human airway smooth muscle cells.

    Science.gov (United States)

    Berntsen, P; Park, C Y; Rothen-Rutishauser, B; Tsuda, A; Sager, T M; Molina, R M; Donaghey, T C; Alencar, A M; Kasahara, D I; Ericsson, T; Millet, E J; Swenson, J; Tschumperlin, D J; Butler, J P; Brain, J D; Fredberg, J J; Gehr, P; Zhou, E H

    2010-06-06

    The past decade has seen significant increases in combustion-generated ambient particles, which contain a nanosized fraction (less than 100 nm), and even greater increases have occurred in engineered nanoparticles (NPs) propelled by the booming nanotechnology industry. Although inhalation of these particulates has become a public health concern, human health effects and mechanisms of action for NPs are not well understood. Focusing on the human airway smooth muscle cell, here we show that the cellular mechanical function is altered by particulate exposure in a manner that is dependent upon particle material, size and dose. We used Alamar Blue assay to measure cell viability and optical magnetic twisting cytometry to measure cell stiffness and agonist-induced contractility. The eight particle species fell into four categories, based on their respective effect on cell viability and on mechanical function. Cell viability was impaired and cell contractility was decreased by (i) zinc oxide (40-100 nm and less than 44 microm) and copper(II) oxide (less than 50 nm); cell contractility was decreased by (ii) fluorescent polystyrene spheres (40 nm), increased by (iii) welding fumes and unchanged by (iv) diesel exhaust particles, titanium dioxide (25 nm) and copper(II) oxide (less than 5 microm), although in none of these cases was cell viability impaired. Treatment with hydrogen peroxide up to 500 microM did not alter viability or cell mechanics, suggesting that the particle effects are unlikely to be mediated by particle-generated reactive oxygen species. Our results highlight the susceptibility of cellular mechanical function to particulate exposures and suggest that direct exposure of the airway smooth muscle cells to particulates may initiate or aggravate respiratory diseases.

  19. Estimate of K-functionals and modulus of smoothness constructed ...

    Indian Academy of Sciences (India)

    Indian Acad. Sci. (Math. Sci.) Vol. 124, No. 2, May 2014, pp. 235–242. c Indian Academy of Sciences. Estimate of K-functionals and modulus of smoothness constructed by generalized spherical mean operator. M EL HAMMA and R DAHER. Department of Mathematics, Faculty of Sciences Aïn Chock, University of Hassan II,.

  20. Asymptotic Theory for Regressions with Smoothly Changing Parameters

    DEFF Research Database (Denmark)

    Hillebrand, Eric Tobias; Medeiros, Marcelo C.; Xu, Junyue

    We derive asymptotic properties of the quasi maximum likelihood estimator of smooth transition regressions when time is the transition variable. The consistency of the estimator and its asymptotic distribution are examined. It is shown that the estimator converges at the usual square-root-of-T ra...

  1. Asymptotic theory for regressions with smoothly changing parameters

    DEFF Research Database (Denmark)

    Hillebrand, Eric; Medeiros, Marcelo; Xu, Junyue

    2013-01-01

    We derive asymptotic properties of the quasi maximum likelihood estimator of smooth transition regressions when time is the transition variable. The consistency of the estimator and its asymptotic distribution are examined. It is shown that the estimator converges at the usual pT-rate and has an ...

  2. Linearity and Misspecification Tests for Vector Smooth Transition Regression Models

    DEFF Research Database (Denmark)

    Teräsvirta, Timo; Yang, Yukai

    The purpose of the paper is to derive Lagrange multiplier and Lagrange multiplier type specification and misspecification tests for vector smooth transition regression models. We report results from simulation studies in which the size and power properties of the proposed asymptotic tests in small...

  3. Smoothed analysis of partitioning algorithms for Euclidean functionals

    NARCIS (Netherlands)

    Bläser, Markus; Manthey, Bodo; Rao, B.V. Raghavendra; Dehne, F.; Iacono, J.; Sack, J.-R.

    2011-01-01

    Euclidean optimization problems such as TSP and minimum-length matching admit fast partitioning algorithms that compute near-optimal solutions on typical instances. We develop a general framework for the application of smoothed analysis to partitioning algorithms for Euclidean optimization problems.

  4. Estimate of K-functionals and modulus of smoothness constructed ...

    Indian Academy of Sciences (India)

    Casablanca, Morocco. E-mail: m_elhamma@yahoo.fr. MS received 17 January 2013. Abstract. Using a generalized spherical mean operator, we define generalized modu- lus of smoothness in the space L2 k. (Rd). Based on the Dunkl operator we define. Sobolev-type space and K-functionals. The main result of the paper ...

  5. Smooth torque speed characteristic of switched reluctance motors

    DEFF Research Database (Denmark)

    Zeng, Hui; Chen, Zhe; Chen, Hao

    2014-01-01

    The torque ripple of switched reluctance motors (SRMs) is the main disadvantage that limits the industrial application of these motors. Although several methods for smooth-toque operation (STO) have been proposed, STO works well only within a certain torque and speed range because...

  6. Water Flow Simulation using Smoothed Particle Hydrodynamics (SPH)

    Science.gov (United States)

    Vu, Bruce; Berg, Jared; Harris, Michael F.

    2014-01-01

    Simulation of water flow from the rainbird nozzles has been accomplished using the Smoothed Particle Hydrodynamics (SPH). The advantage of using SPH is that no meshing is required, thus the grid quality is no longer an issue and accuracy can be improved.

  7. Smoothing identification of systems with small non-linearities

    Czech Academy of Sciences Publication Activity Database

    Kozánek, Jan; Piranda, J.

    2003-01-01

    Roč. 38, č. 1 (2003), s. 71-84 ISSN 0025-6455 R&D Projects: GA ČR GA101/00/1471 Institutional research plan: CEZ:AV0Z2076919 Keywords : identification * small non-linearities * smoothing methods Subject RIV: BI - Acoustics Impact factor: 0.237, year: 2003

  8. education as a means of smooth rural-urban migration

    African Journals Online (AJOL)

    Etsub [ ETSUB

    urban socio-economic problems, can be achieved by making quality education a ... rural surplus labor. This led to a decline in the share of rural population in Western. Europe. Rural-urban migration is believed to help reallocate resources, .... analysis gives a particular emphasis to the role of education in inducing smooth.

  9. Self-organization as an iterative kernel smoothing process.

    Science.gov (United States)

    Mulier, F; Cherkassky, V

    1995-11-01

    Kohonen's self-organizing map, when described in a batch processing mode, can be interpreted as a statistical kernel smoothing problem. The batch SOM algorithm consists of two steps. First, the training data are partitioned according to the Voronoi regions of the map unit locations. Second, the units are updated by taking weighted centroids of the data falling into the Voronoi regions, with the weighing function given by the neighborhood. Then, the neighborhood width is decreased and steps 1, 2 are repeated. The second step can be interpreted as a statistical kernel smoothing problem where the neighborhood function corresponds to the kernel and neighborhood width corresponds to kernel span. To determine the new unit locations, kernel smoothing is applied to the centroids of the Voronoi regions in the topological space. This interpretation leads to some new insights concerning the role of the neighborhood and dimensionality reduction. It also strengthens the algorithm's connection with the Principal Curve algorithm. A generalized self-organizing algorithm is proposed, where the kernel smoothing step is replaced with an arbitrary nonparametric regression method.

  10. Vascular effects of 3-carbomethoxypyridine on rabbit aortic smooth ...

    African Journals Online (AJOL)

    Ach-induced relaxation was observed only in rings with intact endothelium. Also 3-CMP-induced relaxation responses were significantly attenuated in endothelium-denuded rings. Conclusion: The results suggest that 3-CMP elicits relaxation of rabbit aortic smooth muscle activated by depolarization- dependent (high-K+) or ...

  11. Vascular effects of 3-carbomethoxypyridine on rabbit aortic smooth ...

    African Journals Online (AJOL)

    Background: 3-Carbomethoxypyridine (3-CMP) is a methyl nicotinate that has been isolated and characterized from one of the alkaloidal fractions of Pyrenacantha staudtii. No literature is available on its vascular action. The goal of this study was to characterize the mechanism of action of 3-CMP on rabbit aortic smooth ...

  12. Mass transfer from smooth alabaster surfaces in turbulent flows

    Science.gov (United States)

    Opdyke, Bradley N.; Gust, Giselher; Ledwell, James R.

    1987-11-01

    The mass transfer velocity for alabaster plates in smooth-wall turbulent flow is found to vary with the friction velocity according to an analytic solution of the advective diffusion equation. Deployment of alabaster plates on the sea floor can perhaps be used to estimate the viscous stress, and transfer velocities for other species.

  13. Membrane properties of smooth muscle cells in pulmonary hypertensive rats.

    Science.gov (United States)

    Suzuki, H; Twarog, B M

    1982-05-01

    The membrane properties of smooth muscle cells in rat main pulmonary artery (MPA) and small pulmonary artery (SPA) were investigated during chronic normobaric hypoxia and after monocrotaline injection. As chronic pulmonary hypertension developed, pronounced differences between MPA and SPA were observed. These findings may shed light on mechanisms of smooth muscle hypertrophy. 1) The resting membrane potential of smooth muscle in MPA became less negative than the normal (depolarized), whereas the resting membrane potential of smooth muscle in SPA became more negative (hyperpolarized). 2) In MPA, both the length and time constants diminished. 3) In MPA, the maximum membrane depolarization produced by a 10-fold increase in extracellular [K+] decreased. 4) In SPA, the depolarization observed in K+-free solution was more rapid and greater in amplitude, and the transient hyperpolarization following restoration of K+-containing solution increased. 5) In SPA, initial and sustained depolarization evoked by Na+-deficient solutions were increased. 6) Depolarization in MPA was due to increased membrane permeability, perhaps to Cl-, whereas hyperpolarization in SPA could be attributed to increased activity of an electrogenic Na+-K+ pump.

  14. Modulus of smoothness and theorems concerning approximation on compact groups

    Directory of Open Access Journals (Sweden)

    H. Vaezi

    2003-01-01

    Full Text Available We consider the generalized shift operator defined by (Shuf(g=∫Gf(tut−1gdt on a compact group G, and by using this operator, we define “spherical” modulus of smoothness. So, we prove Stechkin and Jackson-type theorems.

  15. Comparative Analysis for Robust Penalized Spline Smoothing Methods

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2014-01-01

    Full Text Available Smoothing noisy data is commonly encountered in engineering domain, and currently robust penalized regression spline models are perceived to be the most promising methods for coping with this issue, due to their flexibilities in capturing the nonlinear trends in the data and effectively alleviating the disturbance from the outliers. Against such a background, this paper conducts a thoroughly comparative analysis of two popular robust smoothing techniques, the M-type estimator and S-estimation for penalized regression splines, both of which are reelaborated starting from their origins, with their derivation process reformulated and the corresponding algorithms reorganized under a unified framework. Performances of these two estimators are thoroughly evaluated from the aspects of fitting accuracy, robustness, and execution time upon the MATLAB platform. Elaborately comparative experiments demonstrate that robust penalized spline smoothing methods possess the capability of resistance to the noise effect compared with the nonrobust penalized LS spline regression method. Furthermore, the M-estimator exerts stable performance only for the observations with moderate perturbation error, whereas the S-estimator behaves fairly well even for heavily contaminated observations, but consuming more execution time. These findings can be served as guidance to the selection of appropriate approach for smoothing the noisy data.

  16. A method of piecewise-smooth numerical branching

    Czech Academy of Sciences Publication Activity Database

    Ligurský, Tomáš; Renard, Y.

    2017-01-01

    Roč. 97, č. 7 (2017), s. 815-827 ISSN 1521-4001 R&D Projects: GA MŠk LQ1602 Institutional support: RVO:68145535 Keywords : numerical branching * piecewise smooth * steady-state problem * contact problem * Coulomb friction Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics http://onlinelibrary.wiley.com/doi/10.1002/zamm.201600219/epdf

  17. Airway smooth muscle cells : regulators of airway inflammation

    NARCIS (Netherlands)

    Zuyderduyn, Suzanne

    2007-01-01

    Airways from asthmatic subjects are more responsive to bronchoconstrictive stimuli than airways from healthy subjects. Airway smooth muscle (ASM) cells mediate contraction of the airways by responding to the bronchoconstrictive stimuli, which was thought to be the primary role of ASM cells. In this

  18. Phenotype modulation of airway smooth muscle in asthma

    NARCIS (Netherlands)

    Wright, David B.; Trian, Thomas; Siddiqui, Sana; Pascoe, Chris D.; Johnson, Jill R.; Dekkers, Bart G. J.; Dakshinamurti, Shyamala; Bagchi, Rushita; Burgess, Janette K.; Kanabar, Varsha; Ojo, Oluwaseun O.

    The biological responses of airway smooth muscle (ASM) are diverse, in part due to ASM phenotype plasticity. ASM phenotype plasticity refers to the ability of ASM cells to change the degree of a variety of functions, including contractility, proliferation, migration and secretion of inflammatory

  19. Smoothing of nanoscale roughness based on the Kelvin effect

    International Nuclear Information System (INIS)

    Yarin, Alexander L; Megaridis, Constantine M; Mattia, Davide; Gogotsi, Yury

    2008-01-01

    A novel method of smoothing surfaces with nanoscale roughness is described, based on the Kelvin effect. The problem of vapor redistribution in cylindrical channels and over rough planar walls with nanoscale texture is posed and solved analytically. Vapor deposition (condensation) on the walls initially produces a deposit emulating the surface landscape. After a saturated state at the deposit surface is reached, the Kelvin effect should result in higher vapor pressure/ concentration near the convex sections of the wall and in lower vapor pressure/ concentration near the concave sections. As a result, local vapor fluxes should arise directed from the locally convex to the locally concave regions. Accordingly, the deposited layer at the wall should vaporize (or sublimate) at the convex sections due to depletion and vapor should condense at the concave sections, thus causing smoothing of physical surface unevenness. This mechanism of smoothing of nanoscale roughness has not been considered in detail or used before, even though the basic physics of the Kelvin effect is well known. In the present work, the smoothing kinetics is predicted and the characteristic timescales are calculated in the general case of axisymmetric and non-axisymmetric perturbations of the cylindrical channel walls, as well as for planar surfaces. In addition, experimental data are presented to show that the theoretically motivated approach is also practically realizable

  20. Classification of smooth structures on a homotopy complex ...

    Indian Academy of Sciences (India)

    c Indian Academy of Sciences. Classification of smooth structures on a homotopy complex projective space. RAMESH KASILINGAM. Theoretical Statistics and ... morphic to the complex projective n-space CPn, where n = 3 and 4. ... is the inclusion map outside of homotopy sphere n and well defined up to topological.

  1. Low-dimensional maps for piecewise smooth oscillators

    Science.gov (United States)

    Pavlovskaia, Ekaterina; Wiercigroch, Marian

    2007-09-01

    Dynamics of the piecewise smooth nonlinear oscillators is considered, for which, general methodology of reducing multidimensional flows to low-dimensional maps is proposed. This includes a definition of piecewise smooth oscillator and creation of a global iterative map providing an exact solution. The global map is comprised of local maps, which are constructed in the smooth sub-regions of phase space. To construct this low-dimensional map, it is proposed to monitor the points of intersections of a chosen boundary between smooth subspaces by a trajectory. The dimension reduction is directly related to the dimension of the chosen boundary, and the lower its dimension is, the larger dimension reduction can be achieved. Full details are given for a drifting impact oscillator, where the five-dimensional flow is reduced to one-dimensional (1D) approximate analytical map. First an exact two-dimensional map has been formulated and analysed. A further reduction to 1D approximate map is introduced and discussed. Standard nonlinear dynamic analysis reveals a complex behaviour ranging from periodic oscillations to chaos, and co-existence of multiple attractors. Accuracy of the constructed maps is examined by comparing with the exact solutions for a wide range of the system parameters.

  2. Adaptive Smoothed Finite Elements (ASFEM) for history dependent material models

    NARCIS (Netherlands)

    Quak, W.; van den Boogaard, Antonius H.; Menary, Gary

    2011-01-01

    A successful simulation of a bulk forming process with finite elements can be difficult due to distortion of the finite elements. Nodal smoothed Finite Elements (NSFEM) are an interesting option for such a process since they show good distortion insensitivity and moreover have locking-free behavior

  3. Smooth Rényi Entropy of Ergodic Quantum Information Sources

    NARCIS (Netherlands)

    Schoenmakers, Berry; Tjoelker, Jilles; Tuyls, Pim; Verbitskiy, Evgeny

    2007-01-01

    We investigate the recently introduced notion of smooth Rényi entropy for the case of ergodic information sources, thereby generalizing previous work which concentrated mainly on i.i.d. information sources. We will actually consider ergodic quantum information sources, of which ergodic classical

  4. Consumption Smoothing And Vulnerability In Four Rural Villages Of ...

    African Journals Online (AJOL)

    Using year long intensive monitoring rural household survey, the study has shown that while covariant shocks lead to change in consumption patterns, idiosyncratic shocks appear to be fully insured using various copying strategies. However, households were less likely sell livestock to smooth income shock during survey ...

  5. Technique for smoothing free-flight oscillation data.

    CSIR Research Space (South Africa)

    Beyers, ME

    1975-01-01

    Full Text Available A technique based on superposition of tricyclic solutions has been proposed for smoothing free-flight angular motion. When incorporated into a conventional tricyclic data reduction program, the method is convenient to use and does not require a...

  6. E-Polytopes in Picard Groups of Smooth Rational Surfaces

    Directory of Open Access Journals (Sweden)

    Jae-Hyouk Lee

    2016-04-01

    Full Text Available In this article, we introduce special divisors (root, line, ruling, exceptional system and rational quartic in smooth rational surfaces and study their correspondences to subpolytopes in Gosset polytopes k 21 . We also show that the sets of rulings and exceptional systems correspond equivariantly to the vertices of 2 k 1 and 1 k 2 via E-type Weyl action.

  7. A method of piecewise-smooth numerical branching

    Czech Academy of Sciences Publication Activity Database

    Ligurský, Tomáš; Renard, Y.

    2017-01-01

    Roč. 97, č. 7 (2017), s. 815-827 ISSN 1521-4001 R&D Projects: GA MŠk LQ1602 Institutional support: RVO:68145535 Keywords : numerical branching * piecewise smooth * steady - state problem * contact problem * Coulomb friction Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics http://onlinelibrary.wiley.com/doi/10.1002/zamm.201600219/epdf

  8. Peptostreptococcus micros smooth and rough genotypes in periodontitis and gingivitis

    NARCIS (Netherlands)

    Kremer, BHA; Loos, BG; van der Velden, U; van Winkelhoff, AJ; Craandijk, J; Bulthuis, HM; Hutter, J; Varoufaki, AS; van Steenbergen, TJM

    Background: Two genotypes can be distinguished within the species Peptostreptococcus micros: a smooth (Sm) and a rough (Rg) type. To date no systematic study has been performed on the prevalence and proportion of both types in untreated periodontitis patients and subjects without destructive

  9. Plasticity of airway smooth muscle phenotype in airway remodeling

    NARCIS (Netherlands)

    Gosens, Reinoud

    2004-01-01

    Isolated smooth muscle cells in culture do not immediately start dividing, even in a medium containing all nutrients required. Before entering the cell cycle, the cells first accomodate their phenotype to their new environment. They lose their contractile properties and modulate to a proliferative

  10. Laser non-uniformity smoothing using gas jets

    Czech Academy of Sciences Publication Activity Database

    Batani, D.; Dezulian, R.; Redaelli, R.; Benocci, R.; Stabile, H.; Canova, F.; Lucchini, G.; Koenig, M.; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Skála, Jiří; Dudžák, Roman; Desai, T.; Tikhonchuk, V.; Faure, B.; Malka, V.

    2008-01-01

    Roč. 112, - (2008), 022045/1-022045/4 ISSN 1742-6588 R&D Projects: GA MŠk(CZ) LC528 EU Projects: European Commission(XE) 506350 - LASER LAB-EUROPE Institutional research plan: CEZ:AV0Z10100523 Keywords : laser smoothing technique * gas jet Subject RIV: BH - Optics, Masers, Laser s

  11. Sharp Embeddings of Besov Spaces with Logarithmic Smoothness

    Czech Academy of Sciences Publication Activity Database

    Gurka, P.; Opic, Bohumír

    2005-01-01

    Roč. 18, č. 1 (2005), s. 81-110 ISSN 1139-1138 R&D Projects: GA ČR(CZ) GA201/01/0333 Institutional research plan: CEZ:AV0Z10190503 Keywords : Besov spaces wirh logarithmic smoothness * Lorentz-Zygmund spaces * sharp embeddings Subject RIV: BA - General Mathematics

  12. A periodic basis system of the smooth approximation space

    Czech Academy of Sciences Publication Activity Database

    Segeth, Karel

    2015-01-01

    Roč. 267, 15 September (2015), s. 436-444 ISSN 0096-3003 R&D Projects: GA ČR GA14-02067S Institutional support: RVO:67985840 Keywords : smooth approximation * data approximation * data interpolation * Fourier transform Subject RIV: BA - General Mathematics Impact factor: 1.345, year: 2015 http://www.sciencedirect.com/science/article/pii/S0096300315001526

  13. Smooth bifurcation for a Signorini problem on a rectangle

    Czech Academy of Sciences Publication Activity Database

    Eisner, J.; Kučera, Milan; Recke, L.

    2012-01-01

    Roč. 137, č. 2 (2012), s. 131-138 ISSN 0862-7959 R&D Projects: GA AV ČR IAA100190805 Institutional research plan: CEZ:AV0Z10190503 Keywords : Signorini problem * smooth bifurcation * variational inequality Subject RIV: BA - General Mathematics http://dml.cz/dmlcz/142859

  14. Suppression of vascular smooth muscle cells' proliferation and ...

    African Journals Online (AJOL)

    This study aimed to determine the effects of valsartan on the proliferation and migration of isolated rat vascular smooth muscle cells (VSMCs) and the expression of phospho-p42/44 mitogen-activated protein kinase (MAPK) promoted by angiotensin II (Ang II). VSMCs from the rat thoracic aorta were cultured by ...

  15. Estimate of K-functionals and modulus of smoothness constructed ...

    Indian Academy of Sciences (India)

    ... and -functionals. The main result of the paper is the proof of the equivalence theorem for a -functional and a modulus of smoothness for the Dunkl transform on R d . Author Affiliations. M El Hamma1 R Daher1. Department of Mathematics, Faculty of Sciences Aïn Chock, University of Hassan II, Casablanca, Morocco ...

  16. HSP20 phosphorylation and airway smooth muscle relaxation

    Directory of Open Access Journals (Sweden)

    Mariam Ba

    2009-06-01

    Full Text Available Mariam Ba1, Cherie A Singer1, Manoj Tyagi2, Colleen Brophy3, Josh E Baker4, Christine Cremo4, Andrew Halayko5, William T Gerthoffer21Department of Pharmacology, University of Nevada School of Medicine, Reno, NV, USA; 2Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL, USA; 3Harrington Department of Biochemistry, Arizona State University, Tempe, AZ, USA; 4Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA; 5Departments of Physiology and Internal Medicine, University of Manitoba, Winnipeg, MB, CanadaAbstract: HSP20 (HSPB6 is a small heat shock protein expressed in smooth muscles that is hypothesized to inhibit contraction when phosphorylated by cAMP-dependent protein kinase. To investigate this hypothesis in airway smooth muscle (ASM we showed that HSP20 was constitutively expressed as well as being inducible in cultured hASM cells by treatment with 1 µM isoproterenol or 10 µM salmeterol. In contrast, a mixture of proinflammatory mediators (interleukin-1β, tumor necrosis factor α, and interferon γ inhibited expression of HSP20 by about 50% in 48 hours. To determine whether phosphorylation of HSP20 is sufficient to induce relaxation, canine tracheal smooth muscle was treated with a cell permeant phosphopeptide that mimics the phosphorylation of HSP20. The HSP20 phosphopeptide antagonized carbacholinduced contraction by 60% with no change in myosin light chain phosphorylation. Recombinant full length HSP20 inhibited skeletal actin binding to smooth muscle myosin subfragment 1 (S1, and recombinant cell permeant TAT-HSP20 S16D mutant reduced F-actin filaments in cultured hASM cells. Carbachol stimulation of canine tracheal smooth muscle tissue caused redistribution of HSP20 from large macromolecular complexes (200–500 kDa to smaller complexes (<60 kDa. The results are consistent with HSP20 expression and macromolecular structure being dynamically regulated in airway

  17. Older Smooth Plains on Mercury Obscured by Impact Features

    Science.gov (United States)

    Byrne, P. K.; Denevi, B. W.; Klimczak, C.; Prockter, L. M.; Solomon, S. C.; Whitten, J.; Head, J. W.

    2012-12-01

    On the basis of morphology and spectral reflectance, the surface of Mercury can be broadly divided into three major terrain types: low-reflectance material, intermediate terrain, and smooth plains. This last terrain type is distinguished morphologically by a comparatively smooth and gently rolling surface, has a lower density of impact craters and basins than other surface units on the planet, and typically occupies low-lying areas. Their smooth texture, embayment of other landforms, and distinctive partial to complete burial of older impact features suggests that most of these plains are probably volcanic in nature. Recent mapping work has shown that smooth plains younger than the end of the late heavy bombardment (LHB) occupy ~30% of Mercury's surface. An outstanding question concerns the distribution and nature of older plains units on the planet, especially those that underlie large impact features and may correspond morphologically to smooth plains but have not yet been mapped accordingly. A preliminary survey of such terrain yielded five exemplar sites: at the Amaral (26.5°S, 117.8°E; 101 km diameter), Mickiewicz (23.2°N, 256.7°E; 103 km), and Vivaldi (13.8°N, 274.1°E; 212 km) basins and at two unnamed features at 53.1°S, 38.6°E (83 km in diameter) and 7.1°N, 38.3°E (118 km). We expect that more thorough mapping will uncover additional candidate areas. In each of the example sites, an extensive continuous ejecta deposit and secondary impact field characterize the proximal and distal facies, respectively, of the impact feature; and in each case, the secondaries field (and impact-sculpted terrain in the case of Vivaldi) is superposed upon patches of plains that otherwise appear smooth and host numerous, flooded antecedent craters tens of kilometers in diameter. Moreover, these smooth patches occur at several ranges of azimuths surrounding each crater or basin, suggesting that they may have formed contiguous units prior to formation of the younger

  18. Smoothed Spectra, Ogives, and Error Estimates for Atmospheric Turbulence Data

    Science.gov (United States)

    Dias, Nelson Luís

    2018-01-01

    A systematic evaluation is conducted of the smoothed spectrum, which is a spectral estimate obtained by averaging over a window of contiguous frequencies. The technique is extended to the ogive, as well as to the cross-spectrum. It is shown that, combined with existing variance estimates for the periodogram, the variance—and therefore the random error—associated with these estimates can be calculated in a straightforward way. The smoothed spectra and ogives are biased estimates; with simple power-law analytical models, correction procedures are devised, as well as a global constraint that enforces Parseval's identity. Several new results are thus obtained: (1) The analytical variance estimates compare well with the sample variance calculated for the Bartlett spectrum and the variance of the inertial subrange of the cospectrum is shown to be relatively much larger than that of the spectrum. (2) Ogives and spectra estimates with reduced bias are calculated. (3) The bias of the smoothed spectrum and ogive is shown to be negligible at the higher frequencies. (4) The ogives and spectra thus calculated have better frequency resolution than the Bartlett spectrum, with (5) gradually increasing variance and relative error towards the low frequencies. (6) Power-law identification and extraction of the rate of dissipation of turbulence kinetic energy are possible directly from the ogive. (7) The smoothed cross-spectrum is a valid inner product and therefore an acceptable candidate for coherence and spectral correlation coefficient estimation by means of the Cauchy-Schwarz inequality. The quadrature, phase function, coherence function and spectral correlation function obtained from the smoothed spectral estimates compare well with the classical ones derived from the Bartlett spectrum.

  19. Full-waveform inversion using a nonlinearly smoothed wavefield

    KAUST Repository

    Li, Yuanyuan

    2017-12-08

    Conventional full-waveform inversion (FWI) based on the least-squares misfit function faces problems in converging to the global minimum when using gradient methods because of the cycle-skipping phenomena. An initial model producing data that are at most a half-cycle away from the observed data is needed for convergence to the global minimum. Low frequencies are helpful in updating low-wavenumber components of the velocity model to avoid cycle skipping. However, low enough frequencies are usually unavailable in field cases. The multiplication of wavefields of slightly different frequencies adds artificial low-frequency components in the data, which can be used for FWI to generate a convergent result and avoid cycle skipping. We generalize this process by multiplying the wavefield with itself and then applying a smoothing operator to the multiplied wavefield or its square to derive the nonlinearly smoothed wavefield, which is rich in low frequencies. The global correlation-norm-based objective function can mitigate the dependence on the amplitude information of the nonlinearly smoothed wavefield. Therefore, we have evaluated the use of this objective function when using the nonlinearly smoothed wavefield. The proposed objective function has much larger convexity than the conventional objective functions. We calculate the gradient of the objective function using the adjoint-state technique, which is similar to that of the conventional FWI except for the adjoint source. We progressively reduce the smoothing width applied to the nonlinear wavefield to naturally adopt the multiscale strategy. Using examples on the Marmousi 2 model, we determine that the proposed FWI helps to generate convergent results without the need for low-frequency information.

  20. Smoothing tautologies, hidden dynamics, and sigmoid asymptotics for piecewise smooth systems

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey, Mike R., E-mail: mike.jeffrey@bristol.ac.uk [Engineering Mathematics, University of Bristol, Merchant Venturer' s Building, Bristol BS8 1UB (United Kingdom)

    2015-10-15

    Switches in real systems take many forms, such as impacts, electronic relays, mitosis, and the implementation of decisions or control strategies. To understand what is lost, and what can be retained, when we model a switch as an instantaneous event, requires a consideration of so-called hidden terms. These are asymptotically vanishing outside the switch, but can be encoded in the form of nonlinear switching terms. A general expression for the switch can be developed in the form of a series of sigmoid functions. We review the key steps in extending Filippov's method of sliding modes to such systems. We show how even slight nonlinear effects can hugely alter the behaviour of an electronic control circuit, and lead to “hidden” attractors inside the switching surface.