DEFF Research Database (Denmark)
Kongsted, Alice; Jørgensen, L V; Bendix, T;
2007-01-01
To evaluate whether smooth pursuit eye movements differed between patients with long-lasting whiplash-associated disorders and controls when using a purely computerized method for the eye movement analysis.......To evaluate whether smooth pursuit eye movements differed between patients with long-lasting whiplash-associated disorders and controls when using a purely computerized method for the eye movement analysis....
DEFF Research Database (Denmark)
Kongsted, Alice; Jørgensen, Lars Vincents; Leboeuf-Yde, Charlotte;
2008-01-01
-year follow-up. SETTING: The study was carried out at a university research centre and participants were recruited from emergency units and general practitioners. SUBJECTS: In all, 262 participants were recruited within 10 days from a whiplash injury. MAIN MEASURES: Smooth pursuit eye movements were tested...... coefficient 0.8, 95% confidence interval (CI) 0.04-1.5), but the association was too weak for the test to discriminate between recovered participants and those with lasting symptoms. CONCLUSIONS: Although reduced smooth pursuit performance at one-year follow-up was associated with persistent neck pain, smooth...
Neurophysiology and Neuroanatomy of Smooth Pursuit in Humans
Lencer, Rebekka; Trillenberg, Peter
2008-01-01
Smooth pursuit eye movements enable us to focus our eyes on moving objects by utilizing well-established mechanisms of visual motion processing, sensorimotor transformation and cognition. Novel smooth pursuit tasks and quantitative measurement techniques can help unravel the different smooth pursuit components and complex neural systems involved…
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.
Neurophysiology and Neuroanatomy of Smooth Pursuit: Lesion Studies
Sharpe, James A.
2008-01-01
Smooth pursuit impairment is recognized clinically by the presence of saccadic tracking of a small object and quantified by reduction in pursuit gain, the ratio of smooth eye movement velocity to the velocity of a foveal target. Correlation of the site of brain lesions, identified by imaging or neuropathological examination, with defective smooth…
Cognitive Processes Involved in Smooth Pursuit Eye Movements
Barnes, G. R.
2008-01-01
Ocular pursuit movements allow moving objects to be tracked with a combination of smooth movements and saccades. The principal objective is to maintain smooth eye velocity close to object velocity, thus minimising retinal image motion and maintaining acuity. Saccadic movements serve to realign the image if it falls outside the fovea, the area of…
Compression of time during smooth pursuit eye movements.
Schütz, Alexander C; Morrone, M Concetta
2010-12-01
Humans have a clear sense for the passage of time, but while implicit motor timing is quite accurate, explicit timing is prone to distortions particularly during action (Wenke & Haggard, 2009) and saccadic eye movements (Morrone, Ross, & Burr, 2005). Here, we investigated whether perceived duration is also affected by the execution of smooth pursuit eye movements, showing a compression of apparent duration similar to that observed during saccades. To this end, we presented two brief bars that marked intervals between 100 and 300 ms and asked subjects to judge their duration during fixation and pursuit. We found a compression of perceived duration for bars modulated in luminance contrast of about 32% and for bars modulated in chromatic contrast of 14% during pursuit compared to fixation. Interestingly, Weber ratios were similar for fixation and pursuit, if they are expressed as ratio between JND and perceived duration. This compression was constant for pursuit speeds from 7 to 14 deg/s and did not occur for intervals marked by auditory events. These results argue for a modality-specific component in the processing of temporal information. PMID:20691204
Smooth ocular pursuit in Chiari type II malformation.
Salman, Michael S; Sharpe, James A; Lillakas, Linda; Steinbach, Martin J; Dennis, Maureen
2007-04-01
Chiari type II malformation (CII) is a congenital anomaly of the cerebellum and brainstem, both important structures for processing smooth ocular pursuit. CII is associated with myelomeningocele and hydrocephalus. We investigated the effects of CII on smooth pursuit (SP) eye movements, and determined the effects of spinal lesion level, number of shunt revisions, nystagmus, and brain dysmorphology on SP. SP was recorded using an infrared eye tracker in 21 participants with CII (11 males, 10 females; age range 8-19y, mean 14y 3mo [SD 3y 2mo]). Thirty-eight healthy children (21 males, 17 females) constituted the comparison group. Participants followed a visual target moving sinusoidally at +/- 10 degrees amplitude, horizontally and vertically at 0.25 or 0.5Hz. SP gains, the ratio of eye to target velocities, were abnormal in the CII group with nystagmus (n= 8). The number of shunt revisions (range 0-10), brain dysmorphology, or spinal lesion level (n= 15 for lower and n= 6 for upper spinal lesion level) did not correlate with SP gains. SP is impaired in children with CII and nystagmus. Abnormal pursuit might be related to the CII dysgenesis or to effects of hydrocephalus. The lack of effect of shunt revisions and abnormal tracking in participants with nystagmus provide evidence that it is related primarily to the cerebellar and brainstem malformation.
The Neural Basis of Smooth Pursuit Eye Movements in the Rhesus Monkey Brain
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…
Target Selection by the Frontal Cortex during Coordinated Saccadic and Smooth Pursuit Eye Movements
Srihasam, Krishna; Bullock, Daniel; Grossberg, Stephen
2009-01-01
Oculomotor tracking of moving objects is an important component of visually based cognition and planning. Such tracking is achieved by a combination of saccades and smooth-pursuit eye movements. In particular, the saccadic and smooth-pursuit systems interact to often choose the same target, and to maximize its visibility through time. How do…
Non-Linearity of Visual Sensitivity and Pursuit Velocity during Smooth Pursuit Eye Movements
Institute of Scientific and Technical Information of China (English)
Xu-Fang Chen; Tao Deng; Hong-Mei Yan
2014-01-01
During pursuit eye movements, whether the relationships among the visual sensitivity, pursuit velocity, and target velocity are linear or non-linear is an old issue. In this study, we reexamined their relationships with seven speeds by a simple character discrimination task using an infrared eye tracker. Our results found that the pursuit velocity and accuracy were non-linearly related with the target velocity. Besides, the perceptual sensitivity was not linearly related with the pursuit velocity either. A significant difference existed between lower (less than 20 deg/s) and higher speeds (greater than 20 deg/s). In addition, we found there was no position bias of visual sensitivity between ahead of and behind the pursuit target, but there was a significant perceptual dissymmetry between horizontal and vertical directions at lower pursuit speeds.
Two distinct visual motion mechanisms for smooth pursuit: evidence from individual differences
Wilmer, Jeremy B.; Nakayama, Ken
2007-01-01
Smooth pursuit eye velocity to a moving target is more accurate after an initial catch-up saccade than before, an enhancement that is poorly understood. We present a novel individual differences based method for identifying mechanisms underlying a physiological response, and use it to test whether visual motion signals driving pursuit differ pre- and postsaccade. Correlating moment-to-moment measurements of pursuit over time with two psychophysical measures of speed estimation during fixation...
COMT val(158)met genotype and smooth pursuit eye movements in schizophrenia
DEFF Research Database (Denmark)
Haraldsson, H Magnus; Ettinger, Ulrich; Magnusdottir, Brynja B;
2009-01-01
The association between the catechol-O-methyltransferase (COMT) val(158)met polymorphism (rs4680) and smooth pursuit eye movements (SPEM) was investigated in 110 schizophrenia patients and 96 controls. Patients had lower steady-state pursuit gain and made more frequent saccades than controls...
[The comparison of characteristics of smooth pursuit in left-handed and right-handed persons].
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).
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
Kalman filtering naturally accounts for visually guided and predictive smooth pursuit dynamics.
Orban de Xivry, Jean-Jacques; Coppe, Sébastien; Blohm, Gunnar; Lefèvre, Philippe
2013-10-30
The brain makes use of noisy sensory inputs to produce eye, head, or arm motion. In most instances, the brain combines this sensory information with predictions about future events. Here, we propose that Kalman filtering can account for the dynamics of both visually guided and predictive motor behaviors within one simple unifying mechanism. Our model relies on two Kalman filters: (1) one processing visual information about retinal input; and (2) one maintaining a dynamic internal memory of target motion. The outputs of both Kalman filters are then combined in a statistically optimal manner, i.e., weighted with respect to their reliability. The model was tested on data from several smooth pursuit experiments and reproduced all major characteristics of visually guided and predictive smooth pursuit. This contrasts with the common belief that anticipatory pursuit, pursuit maintenance during target blanking, and zero-lag pursuit of sinusoidally moving targets all result from different control systems. This is the first instance of a model integrating all aspects of pursuit dynamics within one coherent and simple model and without switching between different parallel mechanisms. Our model suggests that the brain circuitry generating a pursuit command might be simpler than previously believed and only implement the functional equivalents of two Kalman filters whose outputs are optimally combined. It provides a general framework of how the brain can combine continuous sensory information with a dynamic internal memory and transform it into motor commands.
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.
Velocity scaling of cue-induced smooth pursuit acceleration obeys constraints of natural motion.
Ladda, Jennifer; Eggert, Thomas; Glasauer, Stefan; Straube, Andreas
2007-09-01
Information about the future trajectory of a visual target is contained not only in the history of target motion but also in static visual cues, e.g., the street provides information about the car's future trajectory. For most natural moving targets, this information imposes strong constraints on the relation between velocity and acceleration which can be exploited by predictive smooth pursuit mechanisms. We questioned how cue-induced predictive changes in pursuit direction depend on target speed and how cue- and target-induced pursuit interact. Subjects pursued a target entering a +/-90 degrees curve and moving on either a homogeneous background or on a low contrast static band indicating the future trajectory. The cue induced a predictive change of pursuit direction, which occurred before curve onset of the target. The predictive velocity component orthogonal to the initial pursuit direction started later and became faster with increasing target velocity. The predictive eye acceleration increased quadratically with target velocity and was independent of the initial target direction. After curve onset, cue- and target-induced pursuit velocity components were not linearly superimposed. The quadratic increase of eye acceleration with target velocity is consistent with the natural velocity scaling implied by the two-thirds power law, which is a characteristic of biological controlled movements. Comparison with linear pursuit models reveals that the ratio between eye acceleration and actual or expected retinal slip cannot be considered a constant gain factor. To obey a natural velocity scaling, this acceleration gain must linearly increase with target or pursuit velocity. We suggest that gain control mechanisms, which affect target-induced changes of pursuit velocity, act similarly on predictive changes of pursuit induced by static visual cues.
Premotor neurons encode torsional eye velocity during smooth-pursuit eye movements
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.
Information fusion control with time delay for smooth pursuit eye movement.
Zhang, Menghua; Ma, Xin; Qin, Bin; Wang, Guangmao; Guo, Yanan; Xu, Zhigang; Wang, Yafang; Li, Yibin
2016-05-01
Smooth pursuit eye movement depends on prediction and learning, and is subject to time delays in the visual pathways. In this paper, an information fusion control method with time delay is presented, implementing smooth pursuit eye movement with prediction and learning as well as solving the problem of time delays in the visual pathways. By fusing the soft constraint information of the target trajectory of eyes and the ideal control strategy, and the hard constraint information of the eye system state equation and the output equation, optimal estimations of the co-state sequence and the control variable are obtained. The proposed control method can track not only constant velocity, sinusoidal target motion, but also arbitrary moving targets. Moreover, the absolute value of the retinal slip reaches steady state after 0.1 sec. Information fusion control method elegantly describes in a function manner how the brain may deal with arbitrary target velocities, how it implements the smooth pursuit eye movement with prediction, learning, and time delays. These two principles allowed us to accurately describe visually guided, predictive and learning smooth pursuit dynamics observed in a wide variety of tasks within a single theoretical framework. The tracking control performance of the proposed information fusion control with time delays is verified by numerical simulation results.
Information fusion control with time delay for smooth pursuit eye movement.
Zhang, Menghua; Ma, Xin; Qin, Bin; Wang, Guangmao; Guo, Yanan; Xu, Zhigang; Wang, Yafang; Li, Yibin
2016-05-01
Smooth pursuit eye movement depends on prediction and learning, and is subject to time delays in the visual pathways. In this paper, an information fusion control method with time delay is presented, implementing smooth pursuit eye movement with prediction and learning as well as solving the problem of time delays in the visual pathways. By fusing the soft constraint information of the target trajectory of eyes and the ideal control strategy, and the hard constraint information of the eye system state equation and the output equation, optimal estimations of the co-state sequence and the control variable are obtained. The proposed control method can track not only constant velocity, sinusoidal target motion, but also arbitrary moving targets. Moreover, the absolute value of the retinal slip reaches steady state after 0.1 sec. Information fusion control method elegantly describes in a function manner how the brain may deal with arbitrary target velocities, how it implements the smooth pursuit eye movement with prediction, learning, and time delays. These two principles allowed us to accurately describe visually guided, predictive and learning smooth pursuit dynamics observed in a wide variety of tasks within a single theoretical framework. The tracking control performance of the proposed information fusion control with time delays is verified by numerical simulation results. PMID:27230904
Clementz, B A; Farber, R H; Lam, M N; Swerdlow, N. R.
1996-01-01
This study was conducted to evaluate the smooth pursuit system functioning of patients with obsessive-compulsive disorder (OCD). For Study 1, 12 subjects with OCD and 12 nonpsychiatric subjects were administered 9-deg-per-sec ramp stimuli to elicit smooth pursuit eye movements. Consistent with a previous report, patients with OCD did not significantly differ from nonpsychiatric subjects on pursuit gain, or frequency of corrective and intrusive saccades. Patients with OCD, however, had smaller...
Target selection by the frontal cortex during coordinated saccadic and smooth pursuit eye movements.
Srihasam, Krishna; Bullock, Daniel; Grossberg, Stephen
2009-08-01
Oculomotor tracking of moving objects is an important component of visually based cognition and planning. Such tracking is achieved by a combination of saccades and smooth-pursuit eye movements. In particular, the saccadic and smooth-pursuit systems interact to often choose the same target, and to maximize its visibility through time. How do multiple brain regions interact, including frontal cortical areas, to decide the choice of a target among several competing moving stimuli? How is target selection information that is created by a bias (e.g., electrical stimulation) transferred from one movement system to another? These saccade-pursuit interactions are clarified by a new computational neural model, which describes interactions between motion processing areas: the middle temporal area, the middle superior temporal area, the frontal pursuit area, and the dorsal lateral pontine nucleus; saccade specification, selection, and planning areas: the lateral intraparietal area, the frontal eye fields, the substantia nigra pars reticulata, and the superior colliculus; the saccadic generator in the brain stem; and the cerebellum. Model simulations explain a broad range of neuroanatomical and neurophysiological data. These results are in contrast with the simplest parallel model with no interactions between saccades and pursuit other than common-target selection and recruitment of shared motoneurons. Actual tracking episodes in primates reveal multiple systematic deviations from predictions of the simplest parallel model, which are explained by the current model. PMID:18823247
Keep your eyes on the ball: smooth pursuit eye movements enhance prediction of visual motion.
Spering, Miriam; Schütz, Alexander C; Braun, Doris I; Gegenfurtner, Karl R
2011-04-01
Success of motor behavior often depends on the ability to predict the path of moving objects. Here we asked whether tracking a visual object with smooth pursuit eye movements helps to predict its motion direction. We developed a paradigm, "eye soccer," in which observers had to either track or fixate a visual target (ball) and judge whether it would have hit or missed a stationary vertical line segment (goal). Ball and goal were presented briefly for 100-500 ms and disappeared from the screen together before the perceptual judgment was prompted. In pursuit conditions, the ball moved towards the goal; in fixation conditions, the goal moved towards the stationary ball, resulting in similar retinal stimulation during pursuit and fixation. We also tested the condition in which the goal was fixated and the ball moved. Motion direction prediction was significantly better in pursuit than in fixation trials, regardless of whether ball or goal served as fixation target. In both fixation and pursuit trials, prediction performance was better when eye movements were accurate. Performance also increased with shorter ball-goal distance and longer presentation duration. A longer trajectory did not affect performance. During pursuit, an efference copy signal might provide additional motion information, leading to the advantage in motion prediction. PMID:21289135
Human discrimination of visual direction of motion with and without smooth pursuit eye movements
Krukowski, Anton E.; Pirog, Kathleen A.; Beutter, Brent R.; Brooks, Kevin R.; Stone, Leland S.
2003-01-01
It has long been known that ocular pursuit of a moving target has a major influence on its perceived speed (Aubert, 1886; Fleischl, 1882). However, little is known about the effect of smooth pursuit on the perception of target direction. Here we compare the precision of human visual-direction judgments under two oculomotor conditions (pursuit vs. fixation). We also examine the impact of stimulus duration (200 ms vs. 800 ms) and absolute direction (cardinal vs. oblique). Our main finding is that direction discrimination thresholds in the fixation and pursuit conditions are indistinguishable. Furthermore, the two oculomotor conditions showed oblique effects of similar magnitudes. These data suggest that the neural direction signals supporting perception are the same with or without pursuit, despite remarkably different retinal stimulation. During fixation, the stimulus information is restricted to large, purely peripheral retinal motion, while during steady-state pursuit, the stimulus information consists of small, unreliable foveal retinal motion and a large efference-copy signal. A parsimonious explanation of our findings is that the signal limiting the precision of direction judgments is a neural estimate of target motion in head-centered (or world-centered) coordinates (i.e., a combined retinal and eye motion signal) as found in the medial superior temporal area (MST), and not simply an estimate of retinal motion as found in the middle temporal area (MT).
Saccadic and smooth-pursuit eye movements during reading of drifting texts.
Valsecchi, Matteo; Gegenfurtner, Karl R; Schütz, Alexander C
2013-01-01
Reading is a complex visuomotor behavior characterized by an alternation of fixations and saccadic eye movements. Despite the widespread use of drifting texts in various settings, very little is known about eye movements under these conditions. Here we investigated oculomotor behavior during reading of texts which were drifting horizontally or vertically at different speeds. Consistent with previous reports, drifting texts were read by an alternation of smooth-pursuit and saccadic eye movements. Detailed analysis revealed several interactions between smooth pursuit and saccades. On one side, the gain of smooth pursuit was increased after the execution of a saccade. On the other side, the peak velocity of saccades was reduced for the horizontally drifting text, in which saccades and pursuit were executed in opposite directions. In addition, we show that well-known findings from the reading of static texts extend to drifting text, such as the preferred viewing location, the inverted optimal viewing position, and the correlation between saccade amplitude and subsequent pursuit/fixation duration. In general, individual eye-movement parameters such as saccade amplitude and fixation/pursuit durations were correlated across self-paced reading of static text and time-constrained reading of static and drifting texts. These results show that findings from basic oculomotor research also apply to the reading of drifting texts. Similarly, basic reading principles apply to the reading of static and drifting texts in a similar way. This exemplifies the reading of drifting text as a visuomotor behavior which is influenced by low-level eye-movement control as well as by cognitive and linguistic processing.
Murdison, T Scott; Paré-Bingley, Chanel A; Blohm, Gunnar
2013-08-01
To compute spatially correct smooth pursuit eye movements, the brain uses both retinal motion and extraretinal signals about the eyes and head in space (Blohm and Lefèvre 2010). However, when smooth eye movements rely solely on memorized target velocity, such as during anticipatory pursuit, it is unknown if this velocity memory also accounts for extraretinal information, such as head roll and ocular torsion. To answer this question, we used a novel behavioral updating paradigm in which participants pursued a repetitive, spatially constant fixation-gap-ramp stimulus in series of five trials. During the first four trials, participants' heads were rolled toward one shoulder, inducing ocular counterroll (OCR). With each repetition, participants increased their anticipatory pursuit gain, indicating a robust encoding of velocity memory. On the fifth trial, they rolled their heads to the opposite shoulder before pursuit, also inducing changes in ocular torsion. Consequently, for spatially accurate anticipatory pursuit, the velocity memory had to be updated across changes in head roll and ocular torsion. We tested how the velocity memory accounted for head roll and OCR by observing the effects of changes to these signals on anticipatory trajectories of the memory decoding (fifth) trials. We found that anticipatory pursuit was updated for changes in head roll; however, we observed no evidence of compensation for OCR, representing the absence of ocular torsion signals within the velocity memory. This indicated that the directional component of the memory must be coded retinally and updated to account for changes in head roll, but not OCR. PMID:23678014
Model emulates human smooth pursuit system producing zero-latency target tracking.
Bahill, A T; McDonald, J D
1983-01-01
Humans can overcome the 150 ms time delay of the smooth pursuit eye movement system and track smoothly moving visual targets with zero-latency. Our target-selective adaptive control model can also overcome an inherent time delay and produce zero-latency tracking. No other model or man-made system can do this. Our model is physically realizable and physiologically realistic. The technique used in our model should be useful for analyzing other time-delay systems, such as man-machine systems and robots.
Niu, Yu-Qiong; Lisberger, Stephen G.
2011-01-01
We have investigated how visual motion signals are integrated for smooth pursuit eye movements by measuring the initiation of pursuit in monkeys for pairs of moving stimuli of the same or differing luminance. The initiation of pursuit for pairs of stimuli of the same luminance could be accounted for as a vector average of the responses to the two stimuli singly. When stimuli comprised two superimposed patches of moving dot textures, the brighter stimulus suppressed the inputs from the dimmer ...
On the Visual Input Driving Human Smooth-Pursuit Eye Movements
Stone, Leland S.; Beutter, Brent R.; Lorenceau, Jean
1996-01-01
Current computational models of smooth-pursuit eye movements assume that the primary visual input is local retinal-image motion (often referred to as retinal slip). However, we show that humans can pursue object motion with considerable accuracy, even in the presence of conflicting local image motion. This finding indicates that the visual cortical area(s) controlling pursuit must be able to perform a spatio-temporal integration of local image motion into a signal related to object motion. We also provide evidence that the object-motion signal that drives pursuit is related to the signal that supports perception. We conclude that current models of pursuit should be modified to include a visual input that encodes perceived object motion and not merely retinal image motion. Finally, our findings suggest that the measurement of eye movements can be used to monitor visual perception, with particular value in applied settings as this non-intrusive approach would not require interrupting ongoing work or training.
Schrauf, M; Wist, E R; Ehrenstein, W H
2000-04-21
The Scintillating Grid Illusion occurs when small white disks are superimposed onto the intersections of a grey-on-black Hermann grid. As a result illusory dark spots are seen at numerous crossings, flashing with each flick of the eye and changing their location and distribution with each saccade. The illusion is absent with steady fixation. The present study shows that saccadic eye movements are not necessary to produce the illusion. Rather, the illusion was also found to occur (i) during smooth pursuit movements when the grid was stationary, (ii) during smooth displacement of the grid with the gaze kept steady, and (iii) during brief exposures of the stationary grid. It is concluded that, while transient stimulation is essential for generating the illusion, reduction in effective luminance contrast resulting from brief exposure and high stimulus speed are responsible for reductions in its strength.
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…
Leigh, R. J.; Thurston, S. E.; Sharpe, J. A.; Ranalli, P. J.; Hamid, M. A.
1987-01-01
The effects of deficient labyrinthine function on smooth visual tracking with the eyes and head were investigated, using ten patients with bilateral peripheral vestibular disease and ten normal controls. Active, combined eye-head tracking (EHT) was significantly better in patients than smooth pursuit with the eyes alone, whereas normal subjects pursued equally well in both cases. Compensatory eye movements during active head rotation in darkness were always less in patients than in normal subjects. These data were used to examine current hypotheses that postulate central cancellation of the vestibulo-ocular reflex (VOR) during EHT. A model that proposes summation of an integral smooth pursuit command and VOR/compensatory eye movements is consistent with the findings. Observation of passive EHT (visual fixation of a head-fixed target during en bloc rotation) appears to indicate that in this mode parametric gain changes contribute to modulation of the VOR.
Niu, Yu-Qiong; Lisberger, Stephen G
2011-08-01
We have investigated how visual motion signals are integrated for smooth pursuit eye movements by measuring the initiation of pursuit in monkeys for pairs of moving stimuli of the same or differing luminance. The initiation of pursuit for pairs of stimuli of the same luminance could be accounted for as a vector average of the responses to the two stimuli singly. When stimuli comprised two superimposed patches of moving dot textures, the brighter stimulus suppressed the inputs from the dimmer stimulus, so that the initiation of pursuit became winner-take-all when the luminance ratio of the two stimuli was 8 or greater. The dominance of the brighter stimulus could be not attributed to either the latency difference or the ratio of the eye accelerations for the bright and dim stimuli presented singly. When stimuli comprised either spot targets or two patches of dots moving across separate locations in the visual field, the brighter stimulus had a much weaker suppressive influence; the initiation of pursuit could be accounted for by nearly equal vector averaging of the responses to the two stimuli singly. The suppressive effects of the brighter stimulus also appeared in human perceptual judgments, but again only for superimposed stimuli. We conclude that one locus of the interaction of two moving visual stimuli is shared by perception and action and resides in local inhibitory connections in the visual cortex. A second locus resides deeper in sensory-motor processing and may be more closely related to action selection than to stimulus selection. PMID:21593392
Minimization of Retinal Slip Cannot Explain Human Smooth-Pursuit Eye Movements
Stone, Leland S.; Beutter, Brent R.; Null, Cynthia H. (Technical Monitor)
1998-01-01
Existing models assume that pursuit attempts a direct minimization of retinal image motion or "slip" (e.g. Robinson et al., 1986; Krauzlis & Weisberger, 1989). Using occluded line-figure stimuli, we have previously shown that humans can accurately pursue stimuli for which perfect tracking does not zero retinal slip (Neurologic ARCO). These findings are inconsistent with the standard control strategy of matching eye motion to a target-motion signal reconstructed by adding retinal slip and eye motion, but consistent with a visual front-end which estimates target motion via a global spatio-temporal integration for pursuit and perception. Another possible explanation is that pursuit simply attempts to minimize slip perpendicular to the segments (and neglects parallel "sliding" motion). To resolve this, 4 observers (3 naive) were asked to pursue the center of 2 types of stimuli with identical velocity-space descriptions and matched motion energy. The line-figure "diamond" stimulus was viewed through 2 invisible 3 deg-wide vertical apertures (38 cd/m2 equal to background) such that only the sinusoidal motion of 4 oblique line segments (44 cd/m2 was visible. The "cross" was identical except that the segments exchanged positions. Two trajectories (8's and infinity's) with 4 possible initial directions were randomly interleaved (1.25 cycles, 2.5s period, Ax = Ay = 1.4 deg). In 91% of trials, the diamond appeared rigid. Correspondingly, pursuit was vigorous (mean Again: 0.74) with a V/H aspect ratio approx. 1 (mean: 0.9). Despite a valid rigid solution, the cross however appeared rigid in 8% of trials. Correspondingly, pursuit was weaker (mean Hgain: 0.38) with an incorrect aspect ratio (mean: 1.5). If pursuit were just minimizing perpendicular slip, performance would be the same in both conditions.
Ito, Norie; Takei, Hidetoshi; Chiba, Susumu; Inoue, Kiyoharu; Fukushima, Kikuro
2016-01-01
Although impaired smooth-pursuit in Parkinson's disease (PD) is well known, reports are conflicting on the ability to cancel vestibulo-ocular reflex (VOR) when the target moves with head, requiring gaze-pursuit. To compare visual tracking performance with or without passive whole-body rotation, we examined eye movements of 10 PD patients and 6 age-matched controls during sinusoidal horizontal smooth-pursuit and passive whole-body rotation (0.3 Hz, ± 10°). Three tasks were tested: smooth-pursuit, VOR cancellation, and VORx1 while subjects fixated an earth-stationary spot during whole-body rotation. Mean ± SD eye velocity gains (eye velocities/stimulus velocities) of PD patients during the 3 tasks were 0.32 ± 0.24 0.25 ± 0.22, 0.85 ± 0.20, whereas those of controls were 0.91 ± 0.06, 0.14 ± 0.07, 0.94 ± 0.05, respectively. Difference was significant between the two subject groups only during smooth-pursuit. Plotting eye-velocity gains of individual subjects during VOR cancellation against those during smooth-pursuit revealed significant negative linear correlation between the two parameters in the controls, but no correlation was found in PD patients. Based on the regression equation of the controls, we estimated expected eye velocity gains of individual subjects during VOR cancellation from their smooth-pursuit gains. Estimated gains of PD patients during VOR cancellation were significantly different from their actual gains, suggesting that different neural mechanisms operate during VOR cancellation in the controls and PD. PMID:26912226
Ito, Norie; Takei, Hidetoshi; Chiba, Susumu; Inoue, Kiyoharu; Fukushima, Kikuro
2016-01-01
Although impaired smooth-pursuit in Parkinson's disease (PD) is well known, reports are conflicting on the ability to cancel vestibulo-ocular reflex (VOR) when the target moves with head, requiring gaze-pursuit. To compare visual tracking performance with or without passive whole-body rotation, we examined eye movements of 10 PD patients and 6 age-matched controls during sinusoidal horizontal smooth-pursuit and passive whole-body rotation (0.3 Hz, ± 10°). Three tasks were tested: smooth-pursuit, VOR cancellation, and VORx1 while subjects fixated an earth-stationary spot during whole-body rotation. Mean ± SD eye velocity gains (eye velocities/stimulus velocities) of PD patients during the 3 tasks were 0.32 ± 0.24 0.25 ± 0.22, 0.85 ± 0.20, whereas those of controls were 0.91 ± 0.06, 0.14 ± 0.07, 0.94 ± 0.05, respectively. Difference was significant between the two subject groups only during smooth-pursuit. Plotting eye-velocity gains of individual subjects during VOR cancellation against those during smooth-pursuit revealed significant negative linear correlation between the two parameters in the controls, but no correlation was found in PD patients. Based on the regression equation of the controls, we estimated expected eye velocity gains of individual subjects during VOR cancellation from their smooth-pursuit gains. Estimated gains of PD patients during VOR cancellation were significantly different from their actual gains, suggesting that different neural mechanisms operate during VOR cancellation in the controls and PD.
Simulated Hypergravity Alters Vascular Smooth Muscle Cell Proliferation and Motility
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.
M.J. van Tricht; D.H. Nieman; L.J. Bour; T. Boerée; J.H.T.M. Koelman; L. de Haan; D.H. Linszen
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
De Sá Teixeira, Nuno Alexandre
2016-09-01
The memory for the final position of a moving object which suddenly disappears has been found to be displaced forward, in the direction of motion, and downwards, in the direction of gravity. These phenomena were coined, respectively, Representational Momentum and Representational Gravity. Although both these and similar effects have been systematically linked with the functioning of internal representations of physical variables (e.g. momentum and gravity), serious doubts have been raised for a cognitively based interpretation, favouring instead a major role of oculomotor and perceptual factors which, more often than not, were left uncontrolled and even ignored. The present work aims to determine the degree to which Representational Momentum and Representational Gravity are epiphenomenal to smooth pursuit eye movements. Observers were required to indicate the offset locations of targets moving along systematically varied directions after a variable imposed retention interval. Each participant completed the task twice, varying the eye movements' instructions: gaze was either constrained or left free to track the targets. A Fourier decomposition analysis of the localization responses was used to disentangle both phenomena. The results show unambiguously that constraining eye movements significantly eliminates the harmonic components which index Representational Momentum, but have no effect on Representational Gravity or its time course. The found outcomes offer promising prospects for the study of the visual representation of gravity and its neurological substrates. PMID:27106480
Huebner, W. P.; Leigh, R. J.; Seidman, S. H.; Thomas, C. W.; Billian, C.; DiScenna, A. O.; Dell'Osso, L. F.
1992-01-01
1. We used a modeling approach to test the hypothesis that, in humans, the smooth pursuit (SP) system provides the primary signal for cancelling the vestibuloocular reflex (VOR) during combined eye-head tracking (CEHT) of a target moving smoothly in the horizontal plane. Separate models for SP and the VOR were developed. The optimal values of parameters of the two models were calculated using measured responses of four subjects to trials of SP and the visually enhanced VOR. After optimal parameter values were specified, each model generated waveforms that accurately reflected the subjects' responses to SP and vestibular stimuli. The models were then combined into a CEHT model wherein the final eye movement command signal was generated as the linear summation of the signals from the SP and VOR pathways. 2. The SP-VOR superposition hypothesis was tested using two types of CEHT stimuli, both of which involved passive rotation of subjects in a vestibular chair. The first stimulus consisted of a "chair brake" or sudden stop of the subject's head during CEHT; the visual target continued to move. The second stimulus consisted of a sudden change from the visually enhanced VOR to CEHT ("delayed target onset" paradigm); as the vestibular chair rotated past the angular position of the stationary visual stimulus, the latter started to move in synchrony with the chair. Data collected during experiments that employed these stimuli were compared quantitatively with predictions made by the CEHT model. 3. During CEHT, when the chair was suddenly and unexpectedly stopped, the eye promptly began to move in the orbit to track the moving target. Initially, gaze velocity did not completely match target velocity, however; this finally occurred approximately 100 ms after the brake onset. The model did predict the prompt onset of eye-in-orbit motion after the brake, but it did not predict that gaze velocity would initially be only approximately 70% of target velocity. One possible
Kahlon, Maninder; Lisberger, Stephen G.
2000-01-01
We followed simple- and complex-spike firing of Purkinje cells (PCs) in the floccular complex of the cerebellum through learned modifications of the pursuit eye movements of two monkeys. Learning was induced by double steps of target speed in which initially stationary targets move at a “learning” speed for 100 ms and then change to either a higher or lower speed in the same direction. In randomly interleaved control trials, targets moved at the learning speed in the opposite direction. When ...
EMDR Effects on Pursuit Eye Movements
Kapoula, Zoi; Yang, Qing; Bonnet, Audrey; Bourtoire, Pauline; Sandretto, Jean
2010-01-01
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 Eyelin...
Franco, Christopher; Ho, Bernard; Mulholland, Diane; Hou, Guangpei; Islam, Muzharul; Donaldson, Katey; Bendeck, Michelle Patricia
2006-01-01
Remodeling of injured blood vessels is dependent on smooth muscle cells and matrix metalloproteinase activity. Doxycycline is a broad spectrum matrix metalloproteinase inhibitor that is under investigation for the treatment of acute coronary syndromes and aneurysms. In the present study, we examine the mechanisms by which doxycycline inhibits smooth muscle cell responses using a series of in vitro assays that mimic critical steps in pathological vascular remodeling. Doxycycline treatment dram...
EMDR effects on pursuit eye movements.
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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.
von der Thüsen, Jan H; Borensztajn, Keren S.; Moimas, Silvia; van Heiningen, Sandra; Teeling, Peter; Van Berkel, Theo J. C.; Biessen, Erik A. L.
2011-01-01
Insulin-like growth factor-1 (IGF-1) signaling is important for the maintenance of plaque stability in atherosclerosis due to its effects on vascular smooth muscle cell (vSMC) phenotype. To investigate this hypothesis, we studied the effects of the highly inflammatory milieu of the atherosclerotic plaque on IGF-1 signaling and stability-related phenotypic parameters of murine vSMCs in vitro, and the effects of IGF-1 supplementation on plaque phenotype in an atherosclerotic mouse model. M1-pol...
Van Ly, David; Burgess, Janette K.; Brock, Thomas G.; Lee, Tak H.; Black, Judith L.; Oliver, Brian G. G.
2012-01-01
Van Ly D, Burgess JK, Brock TG, Lee TH, Black JL, Oliver BG. Prostaglandins but not leukotrienes alter extracellular matrix protein deposition and cytokine release in primary human airway smooth muscle cells and fibroblasts. Am J Physiol Lung Cell Mol Physiol 303: L239-L250, 2012. First published Ma
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Mohammad Ali Shokrgozar
2010-01-01
Full Text Available Objective: Mesenchymal stem cells (MSCs can be expanded and differentiated intomany mature cell types including smooth muscle cells (SMCs. In addition to growth factor,cyclic stretch contributes to differentiation of stem cells. Mechanical stimuli are criticalto morphological changes, development, regeneration, differentiation and pathology ofmesenchymal tissues. The aim of this study is to investigate effects of cyclic stretch withdiffering amplitudes on morphology and differentiation of mesenchymal stem cells.Materials and Methods: Mesenchymal stem cells are extracted from human bone marrow.Cells are cultured on silicone membrane and exposed to cyclic stretch by a custommade device. Cellular images are captured before and after tests. Effects of 5% and 15%uniaxial strain with 1Hz frequency and 1-8 hour durations on morphology of human mesenchymalstem cells are investigated. It is assumed that environmental factors such asmechanical loading regulate MSCs differentiation to SMCs. Fractal analysis is used toquantify alterations in cellular morphology. An image processing method with a designedcode is used for evaluation of fractal dimension parameter.Results: Results demonstrate statistically significant change in cell morphology due tomechanical stretch. By elevation of strain amplitude and number of load cycles, fractaldimensions of cell images decrease. Such decrease is equivalent to alignment of cells bymechanical stimulus. Cells are differentiated to SMCs purely by cyclic stretch. The initiationand rate of differentiation depend on mechanical conditions.Conclusion: To produce functional SMCs for engineered tissues, MSCs can be exposed to uniaxialcyclic stretch. The functionality of differentiated SMCs depends on loading conditions.
Ca2+-signaling in airway smooth muscle cells is altered in T-bet knock-out mice
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Gamarra Fernando
2006-02-01
Full Text Available Abstract Background Airway smooth muscle cells (ASMC play a key role in bronchial hyperresponsiveness (BHR. A major component of the signaling cascade leading to ASMC contraction is calcium. So far, agonist-induced Ca2+-signaling in asthma has been studied by comparing innate properties of inbred rat or mouse strains, or by using selected mediators known to be involved in asthma. T-bet knock-out (KO mice show key features of allergic asthma such as a shift towards TH2-lymphocytes and display a broad spectrum of asthma-like histological and functional characteristics. In this study, we aimed at investigating whether Ca2+-homeostasis of ASMC is altered in T-bet KO-mice as an experimental model of asthma. Methods Lung slices of 100 to 200 μm thickness were obtained from T-bet KO- and wild-type mice. Airway contraction in response to acetylcholine (ACH was measured by video-microscopy and Ca2+-signaling in single ASMC of lung slices was assessed using two-photon-microscopy. Results Airways from T-bet KO-mice showed increased baseline airway tone (BAT and BHR compared to wild-type mice. This could be mimicked by incubation of lung slices from wild-type mice with IL-13. The increased BAT was correlated with an increased incidence of spontaneous changes in intracellular Ca2+-concentrations, whereas BHR correlated with higher ACH-induced Ca2+-transients and an increased proportion of ASMC showing Ca2+-oscillations. Emptying intracellular Ca2+-stores using caffeine or cyclopiazonic acid induced higher Ca2+-elevations in ASMC from T-bet KO- compared to wild-type mice. Conclusion Altered Ca2+-homeostasis of ASMC contributes to increased BAT and BHR in lung slices from T-bet KO-mice as a murine asthma model. We propose that a higher Ca2+-content of the intracellular Ca2+-stores is involved in the pathophysiology of these changes.
Ca2+-signaling in airway smooth muscle cells is altered in T-bet knock-out mice
Bergner, A; Kellner, J.; da Silva, A. K.; Gamarra, F.; Huber, R M
2006-01-01
Background: Airway smooth muscle cells (ASMC) play a key role in bronchial hyperresponsiveness (BHR). A major component of the signaling cascade leading to ASMC contraction is calcium. So far, agonist-induced Ca2+-signaling in asthma has been studied by comparing innate properties of inbred rat or mouse strains, or by using selected mediators known to be involved in asthma. T-bet knock-out (KO) mice show key features of allergic asthma such as a shift towards T(H)2-lymphocytes and display a b...
Institute of Scientific and Technical Information of China (English)
NOBE Koji; MOMOSE Kazutaka; SAKAI Yasushi
2002-01-01
AIM: To examine the effects of Kampo medicine, Keishi-ka-Shakuyaku-to (TJ-60) on the signal transduction in diabetic gastrointestinal dysfunction. METHODS: Experimental diabetic models were prepared using streptozotocin (STZ)-treated Wistar rats. Randomly selected STZ rats were treated with insulin (12 U@kg-1@d-1) or TJ-60 (1% of food intake). Diacylglycerol (DG) and DG kinase activities were quantified in isolated aortic smooth muscle tissue.RESULTS: One of the key element of the PI-turnover, DG kinase activity in resting state in gastric smooth muscle was significantly increased compared to the control value, and carbachol (CCh)-induced response was not detectable,but it was detected in the control rats. On the other hand resting activity in ileum did not differ from the control, but the CCh-induced responses were suppressed. Treatment with TJ-60 indicated resistant effects for the alteration of DG kinase activities in diabetic intestinal tissues. In order to reveal the mechanism of the effects, total content of DG was measured, because the DG plays important role in the PI-turnover and the DG converted from not only PI but also incorporated glucose under high glucose condition. Patterns of the change in DG levels were similar to those in DG kinase. These results indicate that the effect of TJ-60 occurs at the cellular level of DG. CONCLUSION:Dysfunction of gastrointestinal smooth muscle in diabetes is mediated by an alternation of DG and DG kinase. TJ-60 influences the alteration and relief the dysfunction.
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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.
Jalali, Shirin
2011-01-01
The fast growing field of compressed sensing is founded on the fact that if a signal is 'simple' and has some 'structure', then it can be reconstructed accurately with far fewer samples than its ambient dimension. Many different plausible structures have been explored in this field, ranging from sparsity to low-rankness and to finite rate of innovation. However, there are important abstract questions that are yet to be answered. For instance, what are the general abstract meanings of 'structure' and 'simplicity'? Do there exist universal algorithms for recovering such simple structured objects from fewer samples than their ambient dimension? In this paper, we aim to address these two questions. Using algorithmic information theory tools such as Kolmogorov complexity, we provide a unified method of describing 'simplicity' and 'structure'. We then explore the performance of an algorithm motivated by Ocam's Razor (called MCP for minimum complexity pursuit) and show that it requires $O(k\\log n)$ number of samples...
Veith, Christine; Schermuly, Ralph T; Brandes, Ralf P; Weissmann, Norbert
2016-03-01
Oxygen (O2) is essential for the viability and function of most metazoan organisms and thus is closely monitored at both the organismal and the cellular levels. However, alveoli often encounter decreased O2 levels (hypoxia), leading to activation of physiological or pathophysiological responses in the pulmonary arteries. Such changes are achieved by activation of transcription factors. The hypoxia-inducible factors (HIFs) are the most prominent hypoxia-regulated transcription factors in this regard. HIFs bind to hypoxia-response elements (HREs) in the promoter region of target genes, whose expression and translation allows the organism, amongst other factors, to cope with decreased environmental O2 partial pressure (pO2). However, prolonged HIF activation can contribute to major structural alterations, especially in the lung, resulting in the development of pulmonary hypertension (PH). PH is characterized by a rise in pulmonary arterial pressure associated with pulmonary arterial remodelling, concomitant with a reduced intravascular lumen area. Patients with PH develop right heart hypertrophy and eventually die from right heart failure. Thus, understanding the molecular mechanisms of HIF regulation in PH is critical for the identification of novel therapeutic strategies. This review addresses the relationship of hypoxia and the HIF system with pulmonary arterial dysfunction in PH. We particularly focus on the cellular and molecular mechanisms underlying the HIF-driven pathophysiological processes. PMID:26228924
Stable Principal Component Pursuit
Zhou, Zihan; Wright, John; Candes, Emmanuel; Ma, Yi
2010-01-01
In this paper, we study the problem of recovering a low-rank matrix (the principal components) from a high-dimensional data matrix despite both small entry-wise noise and gross sparse errors. Recently, it has been shown that a convex program, named Principal Component Pursuit (PCP), can recover the low-rank matrix when the data matrix is corrupted by gross sparse errors. We further prove that the solution to a related convex program (a relaxed PCP) gives an estimate of the low-rank matrix that is simultaneously stable to small entrywise noise and robust to gross sparse errors. More precisely, our result shows that the proposed convex program recovers the low-rank matrix even though a positive fraction of its entries are arbitrarily corrupted, with an error bound proportional to the noise level. We present simulation results to support our result and demonstrate that the new convex program accurately recovers the principal components (the low-rank matrix) under quite broad conditions. To our knowledge, this is...
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Guo-Ping Chen
2015-01-01
Full Text Available The proliferation of vascular smooth muscle cells (VSMCs is one of the main features of atherosclerosis induced by high glucose. Mevalonate pathway is an important metabolic pathway that plays a key role in multiple cellular processes. The aim of this study was to define whether the enzyme expression in mevalonate pathway is changed in proliferated VSMCs during atherogenic process in diabetic mice. Diabetes was induced in BALB/c mice with streptozotocin (STZ, 50 mg/kg/day for 5 days. Induction of diabetes with STZ was associated with an increase of lesion area and media thickness after 8 and 16 weeks of diabetes. In aorta, there were overexpressions of some enzymes, including 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR, farnesyl pyrophosphate synthase (FPPS, geranylgeranyl pyrophosphate synthase (GGPPS, farnesyltransferase (FNT, and geranylgeranyltransferase-1 (GGT-1, and unchanged expression of squalene synthase (SQS and phosphor-3-hydroxy-3-methylglutaryl-coenzyme A reductase (P-HMGR in 8 and 16 weeks of diabetes. In vitro, VSMCs were cultured and treated with different glucose concentrations for 48 h. High glucose (22.2 mM induced VSMC proliferation and upregulation of HMGR, FPPS, GGPPS, FNT, and GGT-1 but did not change the expressions of SQS and P-HMGR. In conclusion, altered expression of several key enzymes in the mevalonate pathway may play a potential pathophysiological role in atherogenic process of diabetes macrovascular complication.
Schiffl, H; Fricke, H; Sitter, T
1993-05-01
We have examined cardiovascular pressor responsiveness to infused norepinephrine (NE) as related to endogenous plasma NE and plasma renin and to platelet free cytosolic (Ca2+) in 36 patients with early-stage kidney disease and 27 matched normal subjects. The 27 hypertensive patients and the normal subjects did not differ in blood volume, plasma renin, and NE; however, the hypertensive patients had a higher exchangeable body sodium content. Basal plasma NE levels, the relationship between plasma NE measured during NE infusion and the corresponding NE infusion rate, as well as the total plasma clearance for NE did also not differ significantly between the two study groups. In contrast, the threshold or pressor doses of infused NE significantly decreased in the patients with kidney disease. Antihypertensive pharmacotherapy with (Ca2+) channel blockers and/or loop diuretics normalized blood pressure and cardiovascular NE hyperresponsiveness and reduced blood volume, exchangeable body sodium, and platelet free cytosolic (Ca2+). In contrast, experimental digitalisation as a model for in vivo sodium/potassium adenosine triphosphatase inhibition augmented NE responsiveness and raised platelet free cytosolic (Ca2+). Incubation of platelets from normal subjects with plasma ultrafiltrate from hypertensive patients gave evidence for an endogenous factor capable to raise free cytosolic (Ca2+) and to act synergistically with digoxin. Hypertension secondary to early-stage kidney disease is related to an impairment of sodium excretion leading to an expansion of blood volume and exchangeable body sodium. This may result in increased secretion of endogenous factors, leading to alterations of cytosolic (Ca2+) homeostasis of vascular smooth muscle cells followed by elevated peripheral resistance and thus blood pressure. PMID:8494019
Bhattarai, Yogesh; Fried, David; Gulbransen, Brian; Kadrofske, Mark; Fernandes, Roxanne; Xu, Hui; Galligan, James
2016-08-01
We tested the hypothesis that colonic enteric neurotransmission and smooth muscle cell (SMC) function are altered in mice fed a high-fat diet (HFD). We used wild-type (WT) mice and mice lacking the β1-subunit of the BK channel (BKβ1 (-/-)). WT mice fed a HFD had increased myenteric plexus oxidative stress, a 28% decrease in nitrergic neurons, and a 20% decrease in basal nitric oxide (NO) levels. Circular muscle inhibitory junction potentials (IJPs) were reduced in HFD WT mice. The NO synthase inhibitor nitro-l-arginine (NLA) was less effective at inhibiting relaxations in HFD compared with control diet (CD) WT mice (11 vs. 37%, P < 0.05). SMCs from HFD WT mice had depolarized membrane potentials (-47 ± 2 mV) and continuous action potential firing compared with CD WT mice (-53 ± 2 mV, P < 0.05), which showed rhythmic firing. SMCs from HFD or CD fed BKβ1 (-/-) mice fired action potentials continuously. NLA depolarized membrane potential and caused continuous firing only in SMCs from CD WT mice. Sodium nitroprusside (NO donor) hyperpolarized membrane potential and changed continuous to rhythmic action potential firing in SMCs from HFD WT and BKβ1 (-/-) mice. Migrating motor complexes were disrupted in colons from BKβ1 (-/-) mice and HFD WT mice. BK channel α-subunit protein and β1-subunit mRNA expression were similar in CD and HFD WT mice. We conclude that HFD-induced obesity disrupts inhibitory neuromuscular transmission, SMC excitability, and colonic motility by promoting oxidative stress, loss of nitrergic neurons, and SMC BK channel dysfunction. PMID:27288421
Sinha, Rajnikant
2014-01-01
This book offers an introduction to the theory of smooth manifolds, helping students to familiarize themselves with the tools they will need for mathematical research on smooth manifolds and differential geometry. The book primarily focuses on topics concerning differential manifolds, tangent spaces, multivariable differential calculus, topological properties of smooth manifolds, embedded submanifolds, Sard’s theorem and Whitney embedding theorem. It is clearly structured, amply illustrated and includes solved examples for all concepts discussed. Several difficult theorems have been broken into many lemmas and notes (equivalent to sub-lemmas) to enhance the readability of the book. Further, once a concept has been introduced, it reoccurs throughout the book to ensure comprehension. Rank theorem, a vital aspect of smooth manifolds theory, occurs in many manifestations, including rank theorem for Euclidean space and global rank theorem. Though primarily intended for graduate students of mathematics, the book ...
Campanelli, L
2016-01-01
In the Ratra scenario of inflationary magnetogenesis, the kinematic coupling between the photon and the inflaton undergoes a nonanalytical jump at the end of inflation. Using smooth interpolating analytical forms of the coupling function, we show that such unphysical jump does not invalidate the main prediction of the model, which still represents a viable mechanism for explaining cosmic magnetization. Nevertheless, there is a spurious result associated with the nonanaliticity of the coupling, to wit, the prediction that the spectrum of created photons has a power-law decay in the ultraviolet regime. This issue is discussed using both semiclassical approximation and smooth coupling functions.
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Xianqing Shi
Full Text Available OBJECTIVE: To investigate the changes in the currents of voltage-dependent calcium channels (VDCCs in smooth muscle cells of basilar artery in a rabbit model of subarachnoid hemorrhage (SAH. METHODS: New Zealand white rabbits were randomly divided into five groups: sham (C, normal (N, 24 hours (S1, 48 hours (S2 and 72 hours (S3 after SAH. Non-heparinized autologous arterial blood (1 ml/kg was injected into the cisterna magna to create SAH after intravenous anesthesia, and 1 ml/kg of saline was injected into cisterna magna in the sham group. Rabbits in group N received no injections. Basilar artery in S1, S2, S3 group were isolated at 24, 48, 72 hours after SAH. Basilar artery in group C was isolated at 72 hours after physiological saline injection. Basilar artery smooth muscle cells were isolated for all groups. Whole-cell patch-clamp technique was utilized to record cell membrane capacitance and VDCCs currents. The VDCCs antagonist nifedipine was added to the bath solution to block the Ca(++ channels currents. RESULTS: There were no significant differences in the number of cells isolated, the cell size and membrane capacitance among all the five groups. VDCC currents in the S1-S3 groups had higher amplitudes than those in control and sham groups. The significant change of current amplitude was observed at 72 hours after SAH, which was higher than those of 24 and 48 hours. The VDCCs were shown to expression in human artery smooth muscle cells. CONCLUSIONS: The changes of activation characteristics and voltage-current relationship at 72 hours after SAH might be an important event which leads to a series of molecular events in the microenvironment of the basilar artery smooth muscle cells. This may be the key time point for potential therapeutic intervention against subarachnoid hemorrhage.
Pursuit-evasion differential games
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'.
Dynamics of aerial target pursuit
Pal, S.
2015-12-01
During pursuit and predation, aerial species engage in multitasking behavior that involve simultaneous target detection, tracking, decision-making, approach and capture. The mobility of the pursuer and the target in a three dimensional environment during predation makes the capture task highly complex. Many researchers have studied and analyzed prey capture dynamics in different aerial species such as insects and bats. This article focuses on reviewing the capture strategies adopted by these species while relying on different sensory variables (vision and acoustics) for navigation. In conclusion, the neural basis of these capture strategies and some applications of these strategies in bio-inspired navigation and control of engineered systems are discussed.
The motion/pursuit law for visual depth perception from motion parallax.
Nawrot, Mark; Stroyan, Keith
2009-07-01
One of vision's most important functions is specification of the layout of objects in the 3D world. While the static optical geometry of retinal disparity explains the perception of depth from binocular stereopsis, we propose a new formula to link the pertinent dynamic geometry to the computation of depth from motion parallax. Mathematically, the ratio of retinal image motion (motion) and smooth pursuit of the eye (pursuit) provides the necessary information for the computation of relative depth from motion parallax. We show that this could have been obtained with the approaches of Nakayama and Loomis [Nakayama, K., & Loomis, J. M. (1974). Optical velocity patterns, velocity-sensitive neurons, and space perception: A hypothesis. Perception, 3, 63-80] or Longuet-Higgens and Prazdny [Longuet-Higgens, H. C., & Prazdny, K. (1980). The interpretation of a moving retinal image. Proceedings of the Royal Society of London Series B, 208, 385-397] by adding pursuit to their treatments. Results of a psychophysical experiment show that changes in the motion/pursuit ratio have a much better relationship to changes in the perception of depth from motion parallax than do changes in motion or pursuit alone. The theoretical framework provided by the motion/pursuit law provides the quantitative foundation necessary to study this fundamental visual depth perception ability. PMID:19463848
C Pallus, Adam; G Freedman, Edward
2016-08-01
Gaze pursuit is the coordinated movement of the eyes and head that allows humans and other foveate animals to track moving objects. The control of smooth pursuit eye movements when the head is restrained is relatively well understood, but how the eyes coordinate with concurrent head movements when the head is free remains unresolved. In this study, we describe behavioral tasks that dissociate head and gaze velocity during head-free pursuit in monkeys. Existing models of gaze pursuit propose that both eye and head movements are driven only by the perceived velocity of the visual target and are therefore unable to account for these data. We show that in addition to target velocity, the positions of the eyes in the orbits and the retinal position of the target are important factors for predicting head movement during pursuit. When the eyes are already near their limits, further pursuit in that direction will be accompanied by more head movement than when the eyes are centered in the orbits, even when target velocity is the same. The step-ramp paradigm, often used in pursuit tasks, produces larger or smaller head movements, depending on the direction of the position step, while gaze pursuit velocity is insensitive to this manipulation. Using these tasks, we can reliably evoke head movements with peak velocities much faster than the target's velocity. Under these circumstances, the compensatory eye movements, which are often called counterproductive since they rotate the eyes in the opposite direction, are essential to maintaining accurate gaze velocity.
Highly Scalable Matching Pursuit Signal Decomposition Algorithm
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...
Alterations of Eye Movement Control in Neurodegenerative Movement Disorders
Directory of Open Access Journals (Sweden)
Martin Gorges
2014-01-01
Full Text Available The evolution of the fovea centralis, the most central part of the retina and the area of the highest visual accuracy, requires humans to shift their gaze rapidly (saccades to bring some object of interest within the visual field onto the fovea. In addition, humans are equipped with the ability to rotate the eye ball continuously in a highly predicting manner (smooth pursuit to hold a moving target steadily upon the retina. The functional deficits in neurodegenerative movement disorders (e.g., Parkinsonian syndromes involve the basal ganglia that are critical in all aspects of movement control. Moreover, neocortical structures, the cerebellum, and the midbrain may become affected by the pathological process. A broad spectrum of eye movement alterations may result, comprising smooth pursuit disturbance (e.g., interrupting saccades, saccadic dysfunction (e.g., hypometric saccades, and abnormal attempted fixation (e.g., pathological nystagmus and square wave jerks. On clinical grounds, videooculography is a sensitive noninvasive in vivo technique to classify oculomotion function alterations. Eye movements are a valuable window into the integrity of central nervous system structures and their changes in defined neurodegenerative conditions, that is, the oculomotor nuclei in the brainstem together with their directly activating supranuclear centers and the basal ganglia as well as cortical areas of higher cognitive control of attention.
Orthogonal Matching Pursuit with Replacement
Jain, Prateek; Dhillon, Inderjit S
2011-01-01
In this paper, we consider the problem of compressed sensing where the goal is to recover almost all the sparse vectors using a small number of fixed linear measurements. For this problem, we propose a novel partial hard-thresholding operator that leads to a general family of iterative algorithms. While one extreme of the family yields well known hard thresholding algorithms like ITI (Iterative Thresholding with Inversion) and HTP (Hard Thresholding Pursuit), the other end of the spectrum leads to a novel algorithm that we call Orthogonal Matching Pursuit with Replacement (OMPR). OMPR, like the classic greedy algorithm OMP, adds exactly one coordinate to the support at each iteration, based on the correlation with the current residual. However, unlike OMP, OMPR also removes one coordinate from the support. This simple change allows us to prove that OMPR has the best known guarantees for sparse recovery in terms of the Restricted Isometry Property (a condition on the measurement matrix). In contrast, OMP is kn...
Ca^{2+}-signaling in airway smooth muscle cells is altered in T-bet knock-out mice
Gamarra Fernando; Kemp da Silva Anita; Kellner Julia; Bergner Albrecht; Huber Rudolf M
2006-01-01
Abstract Background Airway smooth muscle cells (ASMC) play a key role in bronchial hyperresponsiveness (BHR). A major component of the signaling cascade leading to ASMC contraction is calcium. So far, agonist-induced Ca2+-signaling in asthma has been studied by comparing innate properties of inbred rat or mouse strains, or by using selected mediators known to be involved in asthma. T-bet knock-out (KO) mice show key features of allergic asthma such as a shift towards TH2-lymphocytes and displ...
Fast First-Order Methods for Stable Principal Component Pursuit
Aybat, Necdet Serhat; Iyengar, Garud
2011-01-01
The stable principal component pursuit (SPCP) problem is a non-smooth convex optimization problem, the solution of which has been shown both in theory and in practice to enable one to recover the low rank and sparse components of a matrix whose elements have been corrupted by Gaussian noise. In this paper, we show how several fast first-order methods can be applied to this problem very efficiently. Specifically, we show that the subproblems that arise when applying optimal gradient methods of Nesterov, alternating linearization methods and alternating direction augmented Lagrangian methods to the SPCP problem either have closed-form solutions or have solutions that can be obtained with very modest effort. All but one of the methods analyzed require at least one of the non-smooth terms in the objective function to be smoothed and obtain an eps-optimal solution to the SPCP problem in O(1/eps) iterations. The method that works directly with the fully non-smooth objective function, is proved to be convergent unde...
The pursuit of perfect packing
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...
The pursuit of perfect packing
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.
Robust PCA via Outlier Pursuit
Xu, Huan; Sanghavi, Sujay
2010-01-01
Singular Value Decomposition (and Principal Component Analysis) is one of the most widely used techniques for dimensionality reduction: successful and efficiently computable, it is nevertheless plagued by a well-known, well-documented sensitivity to outliers. Recent work has considered the setting where each point has a few arbitrarily corrupted components. Yet, in applications of SVD or PCA such as robust collaborative filtering or bioinformatics, malicious agents, defective genes, or simply corrupted or contaminated experiments may effectively yield entire points that are completely corrupted. We present an efficient convex optimization-based algorithm we call Outlier Pursuit, that under some mild assumptions on the uncorrupted points (satisfied, e.g., by the standard generative assumption in PCA problems) recovers the exact optimal low-dimensional subspace, and identifies the corrupted points. Such identification of corrupted points that do not conform to the low-dimensional approximation, is of paramount ...
Peacock, Thomas
2014-11-01
Orders of magnitude larger than surface waves, and so powerful that their generation impacts the lunar orbit, internal waves, propagating disturbances of a density-stratified fluid, are ubiquitous throughout the ocean and atmosphere. Following the discovery of the phenomenon of ``dead water'' by early Arctic explorers and the classic laboratory visualizations of the curious St. Andrew's Cross internal wave pattern, there has been a resurgence of interest in internal waves, inspired by their pivotal roles in local environmental and global climate processes, and their profound impact on ocean and aerospace engineering. We detail our widespread pursuit of internal waves through theoretical modeling, laboratory experiments and field studies, from the Pacific Ocean one thousand miles north and south of Hawaii, to the South China Sea, and on to the Arctic Ocean. We also describe our recent expedition to surf the most striking internal wave phenomenon of them all: the Morning Glory cloud in remote Northwest Australia. This work was supported by the National Science Foundation through a CAREER Grant OCE-064559 and through Grants OCE-1129757 and OCE-1357434, and by the Office of Naval Research through Grants N00014-09-1-0282, N00014-08-1-0390 and N00014-05-1-0575.
Krishna, Nithin; O’Neill, Hugh; Sánchez-Morla, EM; Thaker, Gunvant K.
2014-01-01
Although smooth pursuit eye movement (SPEM) is a reliable endophenotype of schizophrenia., exact underlying cognitive and neural substrates remain unknown. A simple mechanistic model of SPEM assumes an efficient interaction in integrating sensory input from the medial temporal (MT)/ medial superior temporal (MST) brain regions and subsequent motor response through the frontal eye field (FEF). Poor functional connectivity between these two regions could explain impaired motion p...
Pursuit on an Organized Crime Network
Marshak, Charles Z; Bertozzi, Andrea L; D'Orsogña, Maria R
2015-01-01
We model the hierarchical evolution of an organized criminal network via antagonistic recruitment and pursuit processes. Within the recruitment phase, a criminal kingpin enlists new members into the network, who in turn seek out other affiliates. New recruits are linked to established criminals according to a probability distribution that depends on the current network structure. At the same time, law enforcement agents attempt to dismantle the growing organization using pursuit strategies that initiate on the lower level nodes and that unfold as self-avoiding random walks. The global details of the organization are unknown to law enforcement, who must explore the hierarchy node by node. We halt the pursuit when certain local criteria of the network are uncovered, encoding if and when an arrest is made; the criminal network is assumed to be eradicated if the kingpin is arrested. We first analyze recruitment and study the large scale properties of the growing network; later we add pursuit and use numerical sim...
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.
In Pursuit of Land Tenure Security
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 describe the human pursuit for a higher level of land tenure security. Because land tenure security is a perception, the use of stories of human experience introduces the reader to an array of issues a...
Beutter, B. R.; Stone, L. S.
1998-01-01
Although numerous studies have examined the relationship between smooth-pursuit eye movements and motion perception, it remains unresolved whether a common motion-processing system subserves both perception and pursuit. To address this question, we simultaneously recorded perceptual direction judgments and the concomitant smooth eye-movement response to a plaid stimulus that we have previously shown generates systematic perceptual errors. We measured the perceptual direction biases psychophysically and the smooth eye-movement direction biases using two methods (standard averaging and oculometric analysis). We found that the perceptual and oculomotor biases were nearly identical, suggesting that pursuit and perception share a critical motion processing stage, perhaps in area MT or MST of extrastriate visual cortex.
In Pursuit of Land Tenure Security
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 desc
Alphabet: Pursuit of the Fairy Dreams%Alphabet： Pursuit of the Fairy Dreams
Institute of Scientific and Technical Information of China (English)
Wanzy Wang
2012-01-01
On October 26th, 2012, Alphabet, one of the renowned children's wear brands in Chinese domestic markets, released its 2012 Autumn/Winter collections in the city of Ningbo with the theme of "In Pursuit of the Fairy Dreams".
The pursuit flexibility of children with attention-deficit/hyperactive disorder
Directory of Open Access Journals (Sweden)
M-J Chen-Sea
2010-11-01
Full Text Available This research explores the kinematics performance of children with ADHD on the Pursuit Test at four speeds (i.e., 30, 50, 80, 100 millimeters per second to assess their movement flexibility and its quality. The study consists of 23 children with ADHD and 38 normal children. The results have shown that children with ADHD demonstrate a faster speed in movement, along with greater acceleration, and the entire movement process tends to be less smooth. Children with ADHD also demonstrated greater difficulty in motor control while the speeds of pursuit test increased. Discussion regarding children with ADHD had difficulty in implementing close-loop movements, higher-level cognitive processing, and higher-speed activities were proposed. Clinical implications, study limitations and suggestions for future study were provided.
Pursuit and Synchronization in Hydrodynamic Dipoles
Kanso, Eva
2015-01-01
We study theoretically the behavior of a class of hydrodynamic dipoles. This study is motivated by recent experiments on synthetic and biological swimmers in microfluidic \\textit{Hele-Shaw} type geometries. Under such confinement, a swimmer's hydrodynamic signature is that of a potential source dipole, and the long-range interactions among swimmers are obtained from the superposition of dipole singularities. Here, we recall the equations governing the positions and orientations of interacting asymmetric swimmers in doubly-periodic domains, and focus on the dynamics of swimmer pairs. We obtain two families of `relative equilibria'-type solutions that correspond to pursuit and synchronization of the two swimmers, respectively. Interestingly, the pursuit mode is stable for large tail swimmers whereas the synchronization mode is stable for large head swimmers. These results have profound implications on the collective behavior reported in several recent studies on populations of confined microswimmers.
Reframing Our Pursuit of Life Balance
Fuentes, David G.; Ogden, Rachel R.; Ryan-Haddad, Ann; Strang, Aimee F.
2015-01-01
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.
Reframing our pursuit of life balance.
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. PMID:25995509
Extending Korf's ideas on the pursuit problem
Reverte Bernabeu, Juan; Gallego Durán, Francisco; Llorens Largo, Faraón
2008-01-01
The prey-predator pursuit problem is referenced many times in literature. It is a generic multi-agent problem whose solutions could by applied to many particular instances. Solutions proposed usually apply non-supervised learning algorithms to train prey and predators. Most of these solutions criticize the greedy algorithm originally proposed by Korf. However, we believe that the improvement obtained by these new proposals does not pay off with relation to their complexity. The method used...
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...... numerical error accumulation in the inner products or the solution. Furthermore, we empirically compare the computational times of each algorithm over the phase plane....
Comparison of Orthogonal Matching Pursuit Implementations
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 numerical error accumulation in the inner products or the solution. Furthermore, we empirically compare the computational times of each algorithm over the phase plane.
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.
On grey relation projection model based on projection pursuit
Institute of Scientific and Technical Information of China (English)
Wang Shuo; Yang Shanlin; Ma Xijun
2008-01-01
Multidimensional grey relation projection value can be synthesized as one-dimensional projection value by u-sing projection pursuit model.The larger the projection value is,the better the model.Thus,according to the projection value,the best one can be chosen from the model aggregation.Because projection pursuit modeling based on accelera-ting genetic algorithm can simplify the implementation procedure of the projection pursuit technique and overcome its complex calculation as well as the difficulty in implementing its program,a new method can be obtained for choosing the best grey relation projection model based on the projection pursuit technique.
Systematic distortion of perceived 2D shape during smooth pursuit eye movements
Li, HCO; Brenner, E; Cornelissen, FW; Kim, ES
2002-01-01
Even when the retinal image of a static scene is constantly shifting, as occurs when the viewer pursues a small moving object with his or her eyes, the scene is usually correctly perceived to be static. Following early suggestions by von Helmholtz, it is commonly believed that this spatial stability
Learning from Animation: Smooth Pursuits of Synaptic Transmission of an Impulse with Contextual Cues
Directory of Open Access Journals (Sweden)
Pınar Köseoğlu
2013-08-01
Full Text Available Multimedia animations can provide better learning experiences for learners by carrying microscopic science concepts or subjects to macroscopic level. The purpose of this study is to explore how learners with and without prior experience study a multimedia learning material in an only graphically-animated design and in a verbal contextual cue design through eye tracking methodology. A total of 39 undergraduates from the Biology Education Department participated in the study. A three minute animation, describing how the inter-neurons transfer of stimulus happens through synapses, containing two different cue based design (verbal contextual or graphical animated was used to collect data. The animation was transformed to an experiment on an eye tracker to collect eye movements. A repeated measure ANOVA was executed for data analysis. Results showed a significant within subjects’ treatment effect for design types (verbalized cue vs. graphical animation in terms of eye movements while between subjects effects for comparison of prior experience groups were not found being significant. Based on the findings from this study, it is suggested that further studies could be designed with a expert groups as well as expanding the content.
Jarrow, Robert A
2014-01-01
This article reviews the forward rate curve smoothing literature. The key contribution of this review is to link the static curve fitting exercise to the dynamic and arbitrage-free models of the term structure of interest rates. As such, this review introduces more economics to an almost exclusively mathematical exercise, and it identifies new areas for research related to forward rate curve smoothing.
Biswas, Kingshook
2009-01-01
We use techniques of tube-log Riemann surfaces due to R.Perez-Marco to construct a hedgehog containing smooth $C^{\\infty}$ combs. The hedgehog is a common hedgehog for a family of commuting non-linearisable holomorphic maps with a common indifferent fixed point. The comb is made up of smooth curves, and is transversally bi-H\\"older regular.
Vascular smooth muscle cells (SMCs) originate from multiple types of progenitor cells. In the embryo, the most well-studied SMC progenitor is the cardiac neural crest stem cell. Smooth muscle differentiation in the neural crest lineage is controlled by a combination of cell intrinsic factors, includ...
The Pursuit of Identity in Invisible Man
Institute of Scientific and Technical Information of China (English)
谭佳
2013-01-01
Invisible Man is a representative work of black literature in America. In this novel, the writer Ralph Ellison depicts the hero’s growth experience in the white dominated society with his unique narrative techniques. As an individual in a society, the hero in this novel gradually realizes that he is an invisible man in the white dominated society and he doesn ’t have the social sta-tus which can be recognized by the white at all. To change this situation, the hero in this novel suffers many difficulties and hard-ships with an attempt to prove his existence in front of the white and the numerous black fellows and obtain his own identity as a black man which will be recognized by others. This paper tries to explore African American ’s pursuit of identity in Invisible Man by interpreting Ellison’s Invisible Man.
Principal Component Pursuit with Reduced Linear Measurements
Ganesh, Arvind; Wright, John; Ma, Yi
2012-01-01
In this paper, we study the problem of decomposing a superposition of a low-rank matrix and a sparse matrix when a relatively few linear measurements are available. This problem arises in many data processing tasks such as aligning multiple images or rectifying regular texture, where the goal is to recover a low-rank matrix with a large fraction of corrupted entries in the presence of nonlinear domain transformation. We consider a natural convex heuristic to this problem which is a variant to the recently proposed Principal Component Pursuit. We prove that under suitable conditions, this convex program guarantees to recover the correct low-rank and sparse components despite reduced measurements. Our analysis covers both random and deterministic measurement models.
Matching Pursuits with Random Sequential Subdictionaries
Moussallam, Manuel; Richard, Gaël
2011-01-01
Matching pursuits are a family of greedy algorithms widely used in signal processing to solve sparse approximation and recovery problems. They rely on an atom selection step that requires the calculation of numerous projections, which can be computationally costly for big dictionaries and burdens their competitivity in coding applications. Existing bypassing strategies are based on dictionary subsampling and local optimization. We propose to use a non adaptive random sequence of subdictionaries in the decomposition process, thus browsing a larger dictionary space in a probabilistic fashion with no additional projection cost nor parameter estimation. We present some theoretical justifications based on order statistics and experimental evaluation of behavior for sparse approximation and sparse recovery problems. An application to audio signal compression with multiscale time-frequency dictionaries is presented, along with a discussion of the algorithm's complexity and practical implementations.
CF-Pursuit: A Pursuit Method with a Clothoid Fitting and a Fuzzy Controller for Autonomous Vehicles
Directory of Open Access Journals (Sweden)
Yunxiao Shan
2015-09-01
Full Text Available Simple and efficient geometric controllers, like Pure-Pursuit, have been widely used in various types of autonomous vehicles to solve tracking problems. In this paper, we have developed a new pursuit method, named CFPursuit, which has been based on Pure-Pursuit but with certain differences. In CF-Pursuit, in order to reduce fitting errors, we used a clothoid C1 curve to replace the circle employed in Pure-Pursuit. This improvement to the fitting method helps the Pursuit method to decrease tracking errors. As regards the selection of look-ahead distance, we employed a fuzzy system to directly consider the path’s curvature. There are three input variables in this fuzzy system, 6mcurvature, 9mcurvature and 12mcurvature, calculated from the clothoid fit with the current position and the goal position on the defined path. A Sugeno fuzzy model was adapted to output a reasonable look-ahead distance using the experiences of human drivers as well as our own tests. Compared with some other geometric controllers, CF-Pursuit performs better in robustness, cross track errors and stability. The results from field tests have proven the CF-Pursuit is a practical and efficient geometric method for the path tracking problems of autonomous vehicles.
Sebastián MV; Navascués MA
2006-01-01
Fractal methodology provides a general frame for the understanding of real-world phenomena. In particular, the classical methods of real-data interpolation can be generalized by means of fractal techniques. In this paper, we describe a procedure for the construction of smooth fractal functions, with the help of Hermite osculatory polynomials. As a consequence of the process, we generalize any smooth interpolant by means of a family of fractal functions. In particular, the elements of the cla...
Pharmacy Residents’ Pursuit of Academic Positions
Shin, Tiffany R.; Mehta, Bella H.; Rodis, Jennifer L.; Pruchnicki, Maria C.
2015-01-01
Objective. To describe pharmacy residents’ interest in and pursuit of academic positions. Methods. An electronic presurvey and postsurvey were sent to pharmacy residents during the 2011-2012 residency year. The initial survey evaluated residents’ job preferences and interest in academia at the beginning of residency, and the follow-up survey focused on job selection and reasons for pursuing or not pursuing positions in academia. Results. Nine hundred thirty-six residents responded to the initial survey and 630 participated in both the initial and follow-up survey. Forty-eight percent of those responding to both surveys strongly considered a career in academia in the initial survey, 28% applied for an academic position, and 7% accepted a position. Second-year postgraduate residents were more likely than first-year postgraduate residents to apply for and be offered a faculty position. Conclusion. Pharmacy residents are interested in academia. While increasing interest among residents is encouraging for faculty recruitment, the academy should also encourage and develop adequate training experiences to prepare residents to succeed in these positions. PMID:25995513
Asymptotic distributions in the projection pursuit based canonical correlation analysis
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper, associations between two sets of random variables based on the projection pursuit (PP) method are studied. The asymptotic normal distributions of estimators of the PP based canonical correlations and weighting vectors are derived.
The Diasporic Pursuit of Home and Identity: Dynamic Punjabi Transnationalism
Taylor, Steve
2014-01-01
This paper examines the pursuit of home within a diasporic British Indian Punjabi community. It is argued that the British Asian transnational pursuit of home is significantly shaped by the dynamic social context of South Asia as well as social processes within Britain and across the South Asian diaspora. Drawing upon a decade of original, transnational, ethnographic research within the UK and India, I analyze the rapidly changing social context of Punjab, India, and the impact of this upon t...
Divisibility, Smoothness and Cryptographic Applications
Naccache, David; Shparlinski, Igor E.
2008-01-01
This paper deals with products of moderate-size primes, familiarly known as smooth numbers. Smooth numbers play a crucial role in information theory, signal processing and cryptography. We present various properties of smooth numbers relating to their enumeration, distribution and occurrence in various integer sequences. We then turn our attention to cryptographic applications in which smooth numbers play a pivotal role.
Revealed smooth nontransitive preferences
DEFF Research Database (Denmark)
Keiding, Hans; Tvede, Mich
2013-01-01
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...... 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....
Smoothed Particle Hydrodynamic Simulator
Energy Technology Data Exchange (ETDEWEB)
2016-10-05
This code is a highly modular framework for developing smoothed particle hydrodynamic (SPH) simulations running on parallel platforms. The compartmentalization of the code allows for rapid development of new SPH applications and modifications of existing algorithms. The compartmentalization also allows changes in one part of the code used by many applications to instantly be made available to all applications.
Context-specific adaptation of pursuit initiation in humans
Takagi, M.; Abe, H.; Hasegawa, S.; Usui, T.; Hasebe, H.; Miki, A.; Zee, D. S.; Shelhauser, M. (Principal Investigator)
2000-01-01
PURPOSE: To determine if multiple states for the initiation of pursuit, as assessed by acceleration in the "open-loop" period, can be learned and gated by context. METHODS: Four normal subjects were studied. A modified step-ramp paradigm for horizontal pursuit was used to induce adaptation. In an increasing paradigm, target velocity doubled 230 msec after onset; in a decreasing paradigm, it was halved. In the first experiment, vertical eye position (+/-5 degrees ) was used as the context cue, and the training paradigm (increasing or decreasing) changed with vertical eye position. In the second experiment, with vertical position constant, when the target was red, training was decreasing, and when green, increasing. The average eye acceleration in the first 100 msec of tracking was the index of open-loop pursuit performance. RESULTS: With vertical position as the cue, pursuit adaptation differed between up and down gaze. In some cases, the direction of adaptation was in exact accord with the training stimuli. In others, acceleration increased or decreased for both up and down gaze but always in correct relative proportion to the training stimuli. In contrast, multiple adaptive states were not induced with color as the cue. CONCLUSIONS: Multiple values for the relationship between the average eye acceleration during the initiation of pursuit and target velocity could be learned and gated by context. Vertical position was an effective contextual cue but not target color, implying that useful contextual cues must be similar to those occurring naturally, for example, orbital position with eye muscle weakness.
Netherton, Stuart J; Jimmo, Sandra L; Palmer, Daniel; Tilley, Douglas G; Dunkerley, Heather A; Raymond, Daniel R; Russell, James C; Absher, P Marlene; Sage, E Helene; Vernon, Robert B; Maurice, Donald H
2002-04-01
Cardiovascular diseases represent a significant cause of morbidity and mortality in diabetes. Of the many animal models used in the study of non-insulin-dependent (type 2) diabetes, the JCR:LA-cp rat is unique in that it develops insulin resistance in the presence of obesity and manifests both peripheral and coronary vasculopathies. In this animal model, arterial vascular smooth muscle cells (VSMCs) from homozygous obese (cp/cp) rats, but not from age-matched healthy (+/+ or + /cp, collectively defined +/?) littermates, display an " activated" phenotype in vitro and in vivo and have an elevated level of cAMP phosphodiesterase (PDE) activity. In this report, we confirm that cp/cp rat aortic VSMCs have an elevated level of PDE3 activity and show that only particulate PDE3 (PDE3B) activity is elevated. In marked contrast to results obtained in + /? VSMCs, simultaneous activation of adenylyl cyclase and inhibition of PDE3 activity in cp/cp VSMCs synergistically increased cAMP. Although PDE3 inhibition did not potentiate the antimigratory effects of forskolin on +/? VSMCs, PDE3 inhibition did markedly potentiate the forskolin-induced inhibition of migration of cp/cp-derived VSMCs. Although PDE3 activity was elevated in cp/cp rat aortic VSMCs, levels of expression of cytosolic PDE3 (PDE3A) and PDE3B in +/? and cp/cp VSMCs, as well as activation of these enzymes following activation of the cAMP-protein kinase A signaling cascade, were not different. Our data are consistent with an increased role for PDE3 in regulating cAMP-dependent signaling in cp/cp VSMCs and identify PDE3 as a cellular activity potentially responsible for the phenotype of cp/cp VSMCs.
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, with part......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...... forecasting experiment to evaluate its point and density forecasting performances. In all the cases, the dynamic asymmetry in the cycle is efficiently captured by the new model. The GSTAR beats AR and STAR competitors in point forecasting, while this superiority becomes less evident in density forecasting...
Indian Academy of Sciences (India)
Benedictus Margaux
2015-05-01
Let be a scheme. Assume that we are given an action of the one dimensional split torus $\\mathbb{G}_{m,S}$ on a smooth affine -scheme $\\mathfrak{X}$. We consider the limit (also called attractor) subfunctor $\\mathfrak{X}_{}$ consisting of points whose orbit under the given action `admits a limit at 0’. We show that $\\mathfrak{X}_{}$ is representable by a smooth closed subscheme of $\\mathfrak{X}$. This result generalizes a theorem of Conrad et al. (Pseudo-reductive groups (2010) Cambridge Univ. Press) where the case when $\\mathfrak{X}$ is an affine smooth group and $\\mathbb{G}_{m,S}$ acts as a group automorphisms of $\\mathfrak{X}$ is considered. It also occurs as a special case of a recent result by Drinfeld on the action of $\\mathbb{G}_{m,S}$ on algebraic spaces (Proposition 1.4.20 of Drinfeld V, On algebraic spaces with an action of $\\mathfrak{G}_{m}$, preprint 2013) in case is of finite type over a field.
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.
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...
Filtering of Interferometric SAR Phase Images as a Fuzzy Matching-Pursuit Blind Estimation
Directory of Open Access Journals (Sweden)
Luciano Alparone
2005-12-01
Full Text Available We present an original application of fuzzy logic to restoration of phase images from interferometric synthetic aperture radar (InSAR, which are affected by zero-mean uncorrelated noise, whose variance depends on the underlying coherence, thereby yielding a nonstationary random noise process. Spatial filtering of the phase noise is recommended, either before phase unwrapping is accomplished, or simultaneously with it. In fact, phase unwrapping basically relies on a smoothness constraint of the phase field, which is severely hampered by the noise. Space-varying linear MMSE estimation is stated as a problem of matching pursuit, in which the estimator is obtained as an expansion in series of a finite number of prototype estimators, fitting the spatial features of the different statistical classes encountered, for example, fringes and steep slope areas. Such estimators are calculated in a fuzzy fashion through an automatic training procedure. The space-varying coefficients of the expansion are stated as degrees of fuzzy membership of a pixel to each of the estimators. Neither a priori knowledge on the noise variance is required nor particular signal and noise models are assumed. Filtering performances on simulated phase images show a steady SNR improvement over conventional box filtering. Applications of the proposed filter to interferometric phase images demonstrate a superior ability of restoring fringes yet preserving their discontinuities, together with an effective noise smoothing performance, irrespective of locally varying coherence characteristics.
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. The...... combination of Matching Pursuit and SVM for automatic seizure detection has never been tested before, making this a pilot study. Data from red different patients with 6 to 49 seizures are used to test our model. Three patients are recorded with scalp electroencephalography (sEEG) and three with intracranial...
DOPPLERLET BASED TIME-FREQUENCY REPRESENTATION VIA MATCHING PURSUITS
Institute of Scientific and Technical Information of China (English)
Zou Hongxing; Zhou Xiaobo; Dai Qionghai; Li Yanda
2001-01-01
A new time-frequency representation called Dopplerlet transform, which uses the dilated, translated and modulated windowed Doppler signals as its basis functions, is proposed, and the Fourier transform, short-time Fourier transform (including Gabor transform), wavelet transform, and chirplet transform are formulated in one framework of Dopplerlet transform accordingly.It is proved that the matching pursuits based on Dopplerlet basis functions are convergent, and that the energy of residual signals yielded in the decomposition process decays exponentially. Simulation results show that the matching pursuits with Dopplerlet basis functions can characterize compactly a nonstationary signal.
Evolving Pacing Strategies for Team Pursuit Track Cycling
Wagner, Markus; Jordan, Diora; Kroeger, Trent; Neumann, Frank
2011-01-01
Team pursuit track cycling is a bicycle racing sport held on velodromes and is part of the Summer Olympics. It involves the use of strategies to minimize the overall time that a team of cyclists needs to complete a race. We present an optimisation framework for team pursuit track cycling and show how to evolve strategies using metaheuristics for this interesting real-world problem. Our experimental results show that these heuristics lead to significantly better strategies than state-of-art strategies that are currently used by teams of cyclists.
Chases and escapes the mathematics of pursuit and evasion
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
Incompressible smoothed particle hydrodynamics
International Nuclear Information System (INIS)
We present a smoothed particle hydrodynamic model for incompressible fluids. As opposed to solving a pressure Poisson equation in order to get a divergence-free velocity field, here incompressibility is achieved by requiring as a kinematic constraint that the volume of the fluid particles is constant. We use Lagrangian multipliers to enforce this restriction. These Lagrange multipliers play the role of non-thermodynamic pressures whose actual values are fixed through the kinematic restriction. We use the SHAKE methodology familiar in constrained molecular dynamics as an efficient method for finding the non-thermodynamic pressure satisfying the constraints. The model is tested for several flow configurations
Smooth distributions are finitely generated
Drager, Lance D; Park, Efton; Richardson, Ken
2010-01-01
A subbundle of variable dimension inside the tangent bundle of a smooth manifold is called a smooth distribution if it is the pointwise span of a family of smooth vector fields. We prove that all such distributions are finitely generated, meaning that the family may be taken to be a finite collection. Further, we show that the space of smooth sections of such distributions need not be finitely generated as a module over the smooth functions. Our results are valid in greater generality, where the tangent bundle may be replaced by an arbitrary vector bundle.
Multi-target pursuit formation of multi-agent systems
Institute of Scientific and Technical Information of China (English)
Yan Jing; Guan Xin-Ping; Luo Xiao-Yuan
2011-01-01
The main goal of this paper is to design a team of agents that can accomplish multi-target pursuit formation using a developed leader-follower strategy. It is supposed that every target can accept a certain number of agents. First, each agent can automatically choose its target based on the distance from the agent to the target and the number of agents
Is the Study of Happiness a Worthy Scientific Pursuit?
Norrish, Jacolyn M.; Vella-Brodrick, Dianne A.
2008-01-01
This paper critiques the view that the study of happiness is not a worthy scientific pursuit. The happiness set point and hedonic treadmill theories denote the complexity of increasing happiness levels due to genetic limitations and adaptation, however, there is mounting evidence to suggest that with the use of appropriate measures and specific…
Responsible Action Research for the Pursuit of Justice
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…
Approach to Weighted Geometric Evaluation Based on Projection Pursuit
Institute of Scientific and Technical Information of China (English)
Yang Shanlin; Wang Shuo; Gong Daning
2006-01-01
Weighted geometric evaluation approach based on Projection pursuit (PP) model is presented in this paper to optimize the choice of schemes. By using PP model, the multi-dimension evaluation index values of schemes can be synthesized into projection value with one dimension. The scheme with a bigger projection value is much better, so the schemes sample can be an optimized choice according to the projection value of each scheme. The modeling of PP based on accelerating genetic algorithm can predigest the realized process of projection pursuit technique, can overcome the shortcomings of large computation amount and the difficulty of computer programming in traditional projection pursuit methods, and can give a new method for application of projection pursuit technique to optimize choice of schemes by using weighted geometric evaluation. The analysis of an applied sample shows that applying PP model driven directly by samples data to optimize choice of schemes is both simple and feasible, that its projection values are relatively decentralized and profit decision-making, that its applicability and maneuverability are high. It can avoid the shortcoming of subjective weighing method, and its results are scientific and objective.
The Pursuit of Happiness, Stress and Temporomandibular Disorders
Directory of Open Access Journals (Sweden)
D. Marcus
2013-11-01
Full Text Available Mismanaging the pursuit of happiness causes negative psychological effects such as stress and disappointment. The resultant stress often manifests itself as psychological and physical health problems. We explore the problems of measuring happiness according to materialistic wealth and demonstrate that misinterpreting happiness can lead to a stress inducing pursuit. The happiness that human beings pursue is often material-based hedonism whereas eudaimonic happiness has been shown to be a by-product of the pursuit of meaningful activities. Pursuing a predefined happiness, the failure to achieve it and the resistance to it can create stress induced psychosomatic health problems; temporomandibular disorders (TMD are one such example. Masticatory myofascial pain syndrome is a form of TMD that has a strong association to psychological stress. In this paper the research on TMD associated facial pain across different socioeconomic status (SES groups is utilized to compare an objective, stress related physiological disorder with happiness data. We also discuss how the pressures of pursuing socially determined aesthetic happiness such as conforming to society’s expectations of smile and facial aesthetics can drive people to make surgical or orthodontic changes. This review proposes that pursuing happiness has the propensity to cause not only psychological stress but also negative behaviors. We aim to encourage further scientific research that will help to clarify this philosophical pursuit.
Positive affect as informational feedback in goal pursuit
Orehek, Edward; Bessarabova, Elena; Chen, Xiaoyan; Kruglanski, Arie W.
2011-01-01
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 g
Human Reward Pursuit: From Rudimentary to Higher-Level Functions
Bijleveld, E.H.; Custers, R.; Aarts, H.A.G.
2012-01-01
Human reward pursuit is often found to be governed by conscious assessments of expected value and required effort. Yet research has also indicated that rewards are initially valuated and processed outside of awareness by rudimentary brain structures. Building on both of these findings, we propose a
Multiagent pursuit-evasion games: Algorithms and experiments
Kim, Hyounjin
Deployment of intelligent agents has been made possible through advances in control software, microprocessors, sensor/actuator technology, communication technology, and artificial intelligence. Intelligent agents now play important roles in many applications where human operation is too dangerous or inefficient. There is little doubt that the world of the future will be filled with intelligent robotic agents employed to autonomously perform tasks, or embedded in systems all around us, extending our capabilities to perceive, reason and act, and replacing human efforts. There are numerous real-world applications in which a single autonomous agent is not suitable and multiple agents are required. However, after years of active research in multi-agent systems, current technology is still far from achieving many of these real-world applications. Here, we consider the problem of deploying a team of unmanned ground vehicles (UGV) and unmanned aerial vehicles (UAV) to pursue a second team of UGV evaders while concurrently building a map in an unknown environment. This pursuit-evasion game encompasses many of the challenging issues that arise in operations using intelligent multi-agent systems. We cast the problem in a probabilistic game theoretic framework and consider two computationally feasible pursuit policies: greedy and global-max. We also formulate this probabilistic pursuit-evasion game as a partially observable Markov decision process and employ a policy search algorithm to obtain a good pursuit policy from a restricted class of policies. The estimated value of this policy is guaranteed to be uniformly close to the optimal value in the given policy class under mild conditions. To implement this scenario on real UAVs and UGVs, we propose a distributed hierarchical hybrid system architecture which emphasizes the autonomy of each agent yet allows for coordinated team efforts. We then describe our implementation on a fleet of UGVs and UAVs, detailing components such
38 CFR 21.310 - Rate of pursuit of a rehabilitation program.
2010-07-01
... rehabilitation program. 21.310 Section 21.310 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS... 38 U.S.C. Chapter 31 Rate of Pursuit § 21.310 Rate of pursuit of a rehabilitation program. (a... and part-time rate of pursuit of a rehabilitation program by a veteran whose ability to pursue...
Smooth quantum gravity: Exotic smoothness and Quantum gravity
Asselmeyer-Maluga, Torsten
2016-01-01
Over the last two decades, many unexpected relations between exotic smoothness, e.g. exotic $\\mathbb{R}^{4}$, and quantum field theory were found. Some of these relations are rooted in a relation to superstring theory and quantum gravity. Therefore one would expect that exotic smoothness is directly related to the quantization of general relativity. In this article we will support this conjecture and develop a new approach to quantum gravity called \\emph{smooth quantum gravity} by using smoot...
Astrophysical Smooth Particle Hydrodynamics
Rosswog, Stephan
2009-01-01
In this review the basic principles of smooth particle hydrodynamics (SPH) are outlined in a pedagogical fashion. To start, a basic set of SPH equations that is used in many codes throughout the astrophysics community is derived explicitly. Much of SPH's success relies on its excellent conservation properties and therefore the numerical conservation of physical invariants receives much attention throughout this review. The self-consistent derivation of the SPH equations from the Lagrangian of an ideal fluid is the common theme of the remainder of the text. Such a variational approach is applied to derive a modern SPH version of Newtonian hydrodynamics. It accounts for gradients in the local resolution lengths which result in corrective, so-called "grad-h-terms". This strategy naturally carries over to the special-relativistic case for which we derive the corresponding grad-h set of equations. This approach is further generalized to the case of a fluid that evolves on a curved, but fixed background space-time.
Station Keeping through Beacon-referenced Cyclic Pursuit
Galloway, Kevin S.; Dey, Biswadip
2015-01-01
This paper investigates a modification of cyclic constant bearing (CB) pursuit in a multi-agent system in which each agent pays attention to a neighbor and a beacon. The problem admits shape equilibria with collective circling about the beacon, with the circling radius and angular separation of agents determined by choice of parameters in the feedback law. Stability of circling shape equilibria is shown for a 2-agent system, and the results are demonstrated on a collective of mobile robots tr...
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.
Sparse Signals Recovery from Noisy Measurements by Orthogonal Matching Pursuit
Shen, Yi
2011-01-01
Recently, many practical algorithms have been proposed to recover the sparse signal from fewer measurements. Orthogonal matching pursuit (OMP) is one of the most effective algorithm. In this paper, we use the restricted isometry property to analysis the algorithm. We show that, under certain conditions based on the restricted isometry property and the signals, OMP will recover the support of the sparse signal when measurements are corrupted by additive noise.
Wavelet-based multicomponent matching pursuit trace interpolation
Choi, Jihun; Byun, Joongmoo; Seol, Soon Jee; Kim, Young
2016-09-01
Typically, seismic data are sparsely and irregularly sampled due to limitations in the survey environment and these cause problems for key seismic processing steps such as surface-related multiple elimination or wave-equation-based migration. Various interpolation techniques have been developed to alleviate the problems caused by sparse and irregular sampling. Among many interpolation techniques, matching pursuit interpolation is a robust tool to interpolate the regularly sampled data with large receiver separation such as crossline data in marine seismic acquisition when both pressure and particle velocity data are used. Multicomponent matching pursuit methods generally used the sinusoidal basis function, which have shown to be effective for interpolating multicomponent marine seismic data in the crossline direction. In this paper, we report the use of wavelet basis functions which further enhances the performance of matching pursuit methods for de-aliasing than sinusoidal basis functions. We also found that the range of the peak wavenumber of the wavelet is critical to the stability of the interpolation results and the de-aliasing performance and that the range should be determined based on Nyquist criteria. In addition, we reduced the computational cost by adopting the inner product of the wavelet and the input data to find the parameters of the wavelet basis function instead of using L-2 norm minimization. Using synthetic data, we illustrate that for aliased data, wavelet-based matching pursuit interpolation yields more stable results than sinusoidal function-based one when we use not only pressure data only but also both pressure and particle velocity together.
Robust Path-Following for UAV Using Pure Pursuit Guidance
Yamasaki, Takeshi; Takano, Hiroyuki; Baba, Yoriaki
2009-01-01
A robust path-following guidance and control system for a UAV is introduced. Pure pursuit guidance with a receding virtual waypoint is proposed to achieve robust path-following capability for the UAV. The system enables the UAV to recover from huge-tracking-error situations alleviating control saturation. The UAV can be equipped with robustness for any sharply curved path-following and wind turbulence circumstances. An optimal navigation constant according to a given path and a proper recedin...
Multi-target pursuit formation of multi-agent systems
Yan, Jing; Guan, Xin-Ping; Luo, Xiao-Yuan
2011-01-01
The main goal of this paper is to design a team of agents that can accomplish multi-target pursuit formation using a developed leader—follower strategy. It is supposed that every target can accept a certain number of agents. First, each agent can automatically choose its target based on the distance from the agent to the target and the number of agents accepted by the target. In view of the fact that all agents are randomly dispersed in the workplace at the initial time, we present a numbering strategy for them. During the movement of agents, not every agent can always obtain pertinent state information about the targets. So, a developed leader—follower strategy and a pursuit formation algorithm are proposed. Under the proposed method, agents with the same target can maintain a circle formation. Furthermore, it turns out that the pursuit formation algorithm for agents to the desired formation is convergent. Simulation studies are provided to illustrate the effectiveness of the proposed method.
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.
Spatial orientation of optokinetic nystagmus and ocular pursuit during orbital space flight.
Moore, Steven T; Cohen, Bernard; Raphan, Theodore; Berthoz, Alain; Clément, Gilles
2005-01-01
On Earth, eye velocity of horizontal optokinetic nystagmus (OKN) orients to gravito-inertial acceleration (GIA), the sum of linear accelerations acting on the head and body. We determined whether adaptation to micro-gravity altered this orientation and whether ocular pursuit exhibited similar properties. Eye movements of four astronauts were recorded with three-dimensional video-oculography. Optokinetic stimuli were stripes moving horizontally, vertically, and obliquely at 30 degrees/s. Ocular pursuit was produced by a spot moving horizontally or vertically at 20 degrees/s. Subjects were either stationary or were centrifuged during OKN with 1 or 0.5 g of interaural or dorsoventral centripetal linear acceleration. Average eye position during OKN (the beating field) moved into the quick-phase direction by 10 degrees during lateral and upward field movement in all conditions. The beating field did not shift up during downward OKN on Earth, but there was a strong upward movement of the beating field (9 degrees) during downward OKN in the absence of gravity; this likely represents an adaptation to the lack of a vertical 1-g bias in-flight. The horizontal OKN velocity axis tilted 9 degrees in the roll plane toward the GIA during interaural centrifugation, both on Earth and in space. During oblique OKN, the velocity vector tilted towards the GIA in the roll plane when there was a disparity between the direction of stripe motion and the GIA, but not when the two were aligned. In contrast, dorsoventral acceleration tilted the horizontal OKN velocity vector 6 degrees in pitch away from the GIA. Roll tilts of the horizontal OKN velocity vector toward the GIA during interaural centrifugation are consistent with the orientation properties of velocity storage, but pitch tilts away from the GIA when centrifuged while supine are not. We speculate that visual suppression during OKN may have caused the velocity vector to tilt away from the GIA during dorsoventral centrifugation
On the Significance of Demand and Inventory Smoothing Interventions in Supply Chain
S Cannella; 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 two shocks in the market demand, and we measure the effect in term of internal process benefits. Results highlight how a higher level of smoothing can generally improve the operational performance ...
Smooth muscle strips for intestinal tissue engineering.
Directory of Open Access Journals (Sweden)
Christopher M Walthers
Full Text Available Functionally contracting smooth muscle is an essential part of the engineered intestine that has not been replicated in vitro. The purpose of this study is to produce contracting smooth muscle in culture by maintaining the native smooth muscle organization. We employed intact smooth muscle strips and compared them to dissociated smooth muscle cells in culture for 14 days. Cells isolated by enzymatic digestion quickly lost maturity markers for smooth muscle cells and contained few enteric neural and glial cells. Cultured smooth muscle strips exhibited periodic contraction and maintained neural and glial markers. Smooth muscle strips cultured for 14 days also exhibited regular fluctuation of intracellular calcium, whereas cultured smooth muscle cells did not. After implantation in omentum for 14 days on polycaprolactone scaffolds, smooth muscle strip constructs expressed high levels of smooth muscle maturity markers as well as enteric neural and glial cells. Intact smooth muscle strips may be a useful component for engineered intestinal smooth muscle.
Smooth analysis in Banach spaces
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
On the Significance of Demand and Inventory Smoothing Interventions in Supply Chain
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
CD40 and OX40 ligand are increased on stimulated asthmatic airway smooth muscle
Burgess, Janette K; Blake, Anita E; Boustany, Sarah; Johnson, Peter R A; Armour, Carol L; Black, Judith L; Hunt, Nicholas H; Hughes, J Margaret
2005-01-01
BACKGROUND: Severe, persistent asthma is characterized by airway smooth muscle hyperplasia, inflammatory cell infiltration into the smooth muscle, and increased expression of many cytokines, including IL-4, IL-13, IL-1beta, and TNF-alpha. These cytokines have the potential to alter the expression of
SMOOTHING BY CONVEX QUADRATIC PROGRAMMING
Institute of Scientific and Technical Information of China (English)
Bing-sheng He; Yu-mei Wang
2005-01-01
In this paper, we study the relaxed smoothing problems with general closed convex constraints. It is pointed out that such problems can be converted to a convex quadratic minimization problem for which there are good programs in software libraries.
The pursuit of happiness: time, money, and social connection.
Mogilner, Cassie
2010-09-01
Does thinking about time, rather than money, influence how effectively individuals pursue personal happiness? Laboratory and field experiments revealed that implicitly activating the construct of time motivates individuals to spend more time with friends and family and less time working-behaviors that are associated with greater happiness. In contrast, implicitly activating money motivates individuals to work more and socialize less, which (although productive) does not increase happiness. Implications for the relative roles of time versus money in the pursuit of happiness are discussed.
Efficient sensory cortical coding optimizes pursuit eye movements.
Liu, Bing; Macellaio, Matthew V; Osborne, Leslie C
2016-01-01
In the natural world, the statistics of sensory stimuli fluctuate across a wide range. In theory, the brain could maximize information recovery if sensory neurons adaptively rescale their sensitivity to the current range of inputs. Such adaptive coding has been observed in a variety of systems, but the premise that adaptation optimizes behaviour has not been tested. Here we show that adaptation in cortical sensory neurons maximizes information about visual motion in pursuit eye movements guided by that cortical activity. We find that gain adaptation drives a rapid (standard but a description of real sensory computation that manifests in improved behavioural performance. PMID:27611214
The pursuit of happiness: time, money, and social connection.
Mogilner, Cassie
2010-09-01
Does thinking about time, rather than money, influence how effectively individuals pursue personal happiness? Laboratory and field experiments revealed that implicitly activating the construct of time motivates individuals to spend more time with friends and family and less time working-behaviors that are associated with greater happiness. In contrast, implicitly activating money motivates individuals to work more and socialize less, which (although productive) does not increase happiness. Implications for the relative roles of time versus money in the pursuit of happiness are discussed. PMID:20732902
Smooth quantum gravity: Exotic smoothness and Quantum gravity
Asselmeyer-Maluga, Torsten
2016-01-01
Over the last two decades, many unexpected relations between exotic smoothness, e.g. exotic $\\mathbb{R}^{4}$, and quantum field theory were found. Some of these relations are rooted in a relation to superstring theory and quantum gravity. Therefore one would expect that exotic smoothness is directly related to the quantization of general relativity. In this article we will support this conjecture and develop a new approach to quantum gravity called \\emph{smooth quantum gravity} by using smooth 4-manifolds with an exotic smoothness structure. In particular we discuss the appearance of a wildly embedded 3-manifold which we identify with a quantum state. Furthermore, we analyze this quantum state by using foliation theory and relate it to an element in an operator algebra. Then we describe a set of geometric, non-commutative operators, the skein algebra, which can be used to determine the geometry of a 3-manifold. This operator algebra can be understood as a deformation quantization of the classical Poisson alge...
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.
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.
Selective Smoothed Finite Element Method
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The paper examines three selective schemes for the smoothed finite element method (SFEM) which was formulated by incorporating a cell-wise strain smoothing operation into the standard compatible finite element method (FEM). These selective SFEM schemes were formulated based on three selective integration FEM schemes with similar properties found between the number of smoothing cells in the SFEM and the number of Gaussian integration points in the FEM. Both scheme 1 and scheme 2 are free of nearly incompressible locking, but scheme 2 is more general and gives better results than scheme 1. In addition, scheme 2 can be applied to anisotropic and nonlinear situations, while scheme 1 can only be applied to isotropic and linear situations. Scheme 3 is free of shear locking. This scheme can be applied to plate and shell problems. Results of the numerical study show that the selective SFEM schemes give more accurate results than the FEM schemes.
Types, Frequency, and Effectiveness of Responses to Unwanted Pursuit and Stalking
Dutton, Leila B.; Winstead, Barbara A.
2011-01-01
This study investigated the types, frequency, and effectiveness of responses to unwanted pursuit (UP) and stalking after relationship termination. Participants included female and male college students who were either pursued by a former partner or who pursued an ex-partner. Factor analyses of targets' responses to pursuit yielded four factors,…
Autonomous underwater vehicle pursuit of biological specimens in the open ocean
Blanco, Max; Wilson, P.A.
2010-01-01
The pursuit equations in two-dimensional space are examined, and then parametrised in terms of relative velocity and initial range. Several inferences about the behaviour of these equations are drawn. The burst speed of several fish species are tabulated, along with several types of Autonomous Underwater Vehicle. An example pursuit calculation is described.
Smooth halos in the cosmic web
Gaite, Jose
2014-01-01
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 alread...
Smooth maps from clumpy data: Covariance analysis
Lombardi, Marco; Schneider, Peter
2002-01-01
Interpolation techniques play a central role in Astronomy, where one often needs to smooth irregularly sampled data into a smooth map. In a previous article (Lombardi & Schneider 2001), we have considered a widely used smoothing technique and we have evaluated the expectation value of the smoothed map under a number of natural hypotheses. Here we proceed further on this analysis and consider the variance of the smoothed map, represented by a two-point correlation function. We show that two ma...
Deficit of pursuit ocular movements in early Alzheimer's disease
Institute of Scientific and Technical Information of China (English)
Francesco Cordici; Pietro Lanzafame; Silvia Marino; Alessandro Celona; Lilla Bonanno; Annalisa Baglieri; Alessia Bramanti; Placido Bramanti
2010-01-01
Previous studies have demonstrated that advanced Alzheimer's disease(AD)patients have deficiency of eye movements.However,there have been no reports on eye movement in the early stages of AD.The aim of this study was to evaluate pursuit ocular movements(POM)provided by a vision-based non-intrusive eye tracker in patients with early AD.POM values were significantly lower in AD patients than in normal controls(P < 0.01).In AD patients,POM values were not closely correlated with the Mini-Mental State Examination scores(P = 0.3).There was no significant difference in POM values among patients treated with or without anticholinesterase therapy.We used a vision-based method,for non-intrusive eye tracking,which can be proposed as a possible tool for supporting the diagnosis of early AD.
Sparse reconstruction using distribution agnostic bayesian matching pursuit
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.
Pursuit of Optimal Relevance in Guide-interpretation
Institute of Scientific and Technical Information of China (English)
贾俊南; 巨玉红
2013-01-01
Optimal relevance, the core notion of Relevance Theory, has a strong explanatory power in regard to adoption of different interpretation strategies. In terms of Relevance Theory, the whole course of guide-interpretation is the reflection of continuous searching for the related matter, i.e. the optimal relevance. It is proved that the most desirable, or in other words, the optimal guide-interpretation can only be achieved by minimizing foreign tourists＇ processing efforts and maximizing guide-interpretation＇ s contextual effect. This paper attempts to analyze guide-interpretation under the guidance of the principle of relevance, with the purpose of arousing guide-interpreters＇ awareness of maximizing their subjectivity and sparing no effort in pursuit of optimal guide-interpretation, which acts as the key to achieving an unforgettable and meaningful tour.
Support agnostic Bayesian matching pursuit for block sparse signals
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.
The Pivotal Role of Airway Smooth Muscle in Asthma Pathophysiology
Patrick Berger; Roger Marthan; Thomas Trian; Pierre-Olivier Girodet; Benoit Allard; Imane Bara; Annaïg Ozier
2011-01-01
Asthma is characterized by the association of airway hyperresponsiveness (AHR), inflammation, and remodelling. The aim of the present article is to review the pivotal role of airway smooth muscle (ASM) in the pathophysiology of asthma. ASM is the main effector of AHR. The mechanisms of AHR in asthma may involve a larger release of contractile mediators and/or a lower release of relaxant mediators, an improved ASM cell excitation/contraction coupling, and/or an alteration in the contraction/lo...
Very Smooth Points of Spaces of Operators
Indian Academy of Sciences (India)
T S S R K Rao
2003-02-01
In this paper we study very smooth points of Banach spaces with special emphasis on spaces of operators. 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. We show that if for every equivalent norm on a Banach space, the dual unit 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.
Smoothing of mixed complementarity problems
Energy Technology Data Exchange (ETDEWEB)
Gabriel, S.A.; More, J.J. [Argonne National Lab., IL (United States). Mathematics and Computer Science Div.
1995-09-01
The authors introduce a smoothing approach to the mixed complementarity problem, and study the limiting behavior of a path defined by approximate minimizers of a nonlinear least squares problem. The main result guarantees that, under a mild regularity condition, limit points of the iterates are solutions to the mixed complementarity problem. The analysis is applicable to a wide variety of algorithms suitable for large-scale mixed complementarity problems.
Beam smoothing and temporal effects
International Nuclear Information System (INIS)
Until recently, and in spite of the introduction of smoothing methods, direct drive laser fusion received lots of setbacks from experiments, this being due to nonlinear and anomalous phenomena. This report deals with a method of analysis which, as self-generated von-Laue gratings, preventing the propagation of laser radiation through the outermost plasma corona, and preventing energy deposition. (TEC). 36 refs., 5 figs
Subsampling in Smoothed Range Spaces
Phillips, Jeff M.; Zheng, Yan
2015-01-01
We consider smoothed versions of geometric range spaces, so an element of the ground set (e.g. a point) can be contained in a range with a non-binary value in $[0,1]$. Similar notions have been considered for kernels; we extend them to more general types of ranges. We then consider approximations of these range spaces through $\\varepsilon $-nets and $\\varepsilon $-samples (aka $\\varepsilon$-approximations). We characterize when size bounds for $\\varepsilon $-samples on kernels can be extended...
Smooth Optimization with Approximate Gradient
d'Aspremont, Alexandre
2005-01-01
We show that the optimal complexity of Nesterov's smooth first-order optimization algorithm is preserved when the gradient is only computed up to a small, uniformly bounded error. In applications of this method to semidefinite programs, this means in some instances computing only a few leading eigenvalues of the current iterate instead of a full matrix exponential, which significantly reduces the method's computational cost. This also allows sparse problems to be solved efficiently using spar...
Pharmacology of airway smooth muscle proliferation
Gosens, Reinoud; Roscioni, Sara S.; Dekkers, Bart G. J.; Pera, Tonio; Schmidt, Martina; Schaafsma, Dedmer; Zaagsma, Johan; Meurs, Herman
2008-01-01
Airway smooth muscle thickening is a pathological feature that contributes significantly to airflow limitation and airway hyperresponsiveness in asthma. Ongoing research efforts aimed at identifying the mechanisms responsible for the increased airway smooth muscle mass have indicated that hyperplasi
A SAS IML Macro for Loglinear Smoothing
Moses, Tim; von Davier, Alina
2011-01-01
Polynomial loglinear models for one-, two-, and higher-way contingency tables have important applications to measurement and assessment. They are essentially regarded as a smoothing technique, which is commonly referred to as loglinear smoothing. A SAS IML (SAS Institute, 2002a) macro was created to implement loglinear smoothing according to…
Action and pursuit of the summit of the earth
International Nuclear Information System (INIS)
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
Newtonized Orthogonal Matching Pursuit: Frequency Estimation Over the Continuum
Mamandipoor, Babak; Ramasamy, Dinesh; Madhow, Upamanyu
2016-10-01
We propose a fast sequential algorithm for the fundamental problem of estimating frequencies and amplitudes of a noisy mixture of sinusoids. The algorithm is a natural generalization of Orthogonal Matching Pursuit (OMP) to the continuum using Newton refinements, and hence is termed Newtonized OMP (NOMP). Each iteration consists of two phases: detection of a new sinusoid, and sequential Newton refinements of the parameters of already detected sinusoids. The refinements play a critical role in two ways: (1) sidestepping the potential basis mismatch from discretizing a continuous parameter space, (2) providing feedback for locally refining parameters estimated in previous iterations. We characterize convergence, and provide a Constant False Alarm Rate (CFAR) based termination criterion. By benchmarking against the Cramer Rao Bound, we show that NOMP achieves near-optimal performance under a variety of conditions. We compare the performance of NOMP with classical algorithms such as MUSIC and more recent Atomic norm Soft Thresholding (AST) and Lasso algorithms, both in terms of frequency estimation accuracy and run time.
Crack growth sparse pursuit for wind turbine blade
Li, Xiang; Yang, Zhibo; Zhang, Han; Du, Zhaohui; Chen, Xuefeng
2015-01-01
One critical challenge to achieving reliable wind turbine blade structural health monitoring (SHM) is mainly caused by composite laminates with an anisotropy nature and a hard-to-access property. The typical pitch-catch PZTs approach generally detects structural damage with both measured and baseline signals. However, the accuracy of imaging or tomography by delay-and-sum approaches based on these signals requires improvement in practice. Via the model of Lamb wave propagation and the establishment of a dictionary that corresponds to scatters, a robust sparse reconstruction approach for structural health monitoring comes into view for its promising performance. This paper proposes a neighbor dictionary that identifies the first crack location through sparse reconstruction and then presents a growth sparse pursuit algorithm that can precisely pursue the extension of the crack. An experiment with the goal of diagnosing a composite wind turbine blade with an artificial crack is performed, and it validates the proposed approach. The results give competitively accurate crack detection with the correct locations and extension length.
Effects of priming goal pursuit on implicit sequence learning
Gamble, Katherine R.; Lee, Joanna M.; Howard, James H.; Howard, Darlene V.
2016-01-01
Implicit learning, the type of learning that occurs without intent to learn or awareness of what has been learned, has been thought to be insensitive to the effects of priming, but recent studies suggest this is not the case. One study found that learning in the Serial Reaction Time (SRT) task was improved by nonconscious goal pursuit, primed via a word search task (Eitam et al., 2008). In two studies, we used the goal priming word search task from Eitam et al., but with a different version of the SRT, the Alternating Serial Reaction Time task (ASRT). Unlike the SRT, which often results in explicit knowledge and assesses sequence learning at one point in time, the ASRT has been shown to be implicit through sensitive measures of judgment, and it enables sequence learning to be measured continuously. In both studies, we found that implicit learning was superior in the groups that were primed for goal achievement compared to control groups, but the effect was transient. We discuss possible reasons for the observed time course of the positive effects of goal priming, as well as some future areas of investigation to better understand the mechanisms that underlie this effect, which could lead to methods to prolong the positive effects. PMID:25084974
Coal Calorific Value Prediction Based on Projection Pursuit Principle
Directory of Open Access Journals (Sweden)
QI Minfang
2012-10-01
Full Text Available The calorific value of coal is an important factor for the economic operation of coal-fired power plant. However, calorific value is tremendous difference between the different coal, and even if coal is from the same mine. Restricted by the coal market, most of coal fired power plants can not burn the designed-coal by now in China. The properties of coal as received are changing so frequently that pulverized coal firing is always with the unexpected condition. Therefore, the researches on the prediction of calorific value of coal have a profound significance for the economic operation of power plants. Aiming at the problem of uncertainty of coal calorific value, establish a soft measurement model for calorific value of coal based on projection pursuit principle combined with genetic algorithm to optimize parameters, and support vector machine algorithm. It is shown by an example that the model has a stronger objectivity, effective and feasible for avoiding the disadvantage of the artificially decided weights of feature indexes. The model could provide a good guidance for the calculation of the coal calorific value and optimization operation of coal-fired power plants.
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.
Hartman, Rhea; Blustein, Leona; Morel, Diane; Davis, Lisa
2014-01-01
Objective. To design and implement 2 pharmaceutical industry elective courses and assess their impact on students’ selection of advanced pharmacy practice experiences (APPEs) and pursuit of pharmaceutical industry fellowships.
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.
Institute of Scientific and Technical Information of China (English)
XU Zi-rong; ZHANG Yi-fei
2011-01-01
The paper studies on case-based reasoning of uncertain product attributes in configuration design of a product family. Interval numbers characterize uncertain product attributes. By interpolating a number of certain values randomly to replace interval numbers and making projection pursuit analysis on source cases and target cases of expanded numbers, we can get a projection value in the optimal projection direction. Based on projection value, we can construct a case retrieval model of projection pursuit that can handle coexisting certain and uncertain product attributes. The application examples of chainsaw configuration design show that case retrieval is highly sensitive to reliable results.
Toward Simulating Realistic Pursuit-Evasion Using a Roadmap-Based Approach
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.
Total curvature and simple pursuit on domains of curvature bounded above
Alexander, S.; Bishop, R; Ghrist, R.
2009-01-01
We show how circumradius and asymptotic behavior of curves in CAT(0) and CAT(K) spaces(K>0) are controlled by growth rates of total curvature. We apply our results to pursuit and evasion games of capture type with simple pursuit motion, generalizing results that are known for convex Euclidean domains, and obtaining results that are new for convex Euclidean domains and hold on playing fields vastly more general than these.
Comparison of some nonlinear smoothing methods
International Nuclear Information System (INIS)
Due to the poor quality of many nuclear medicine images, computer-driven smoothing procedures are frequently employed to enhance the diagnostic utility of these images. While linear methods were first tried, it was discovered that nonlinear techniques produced superior smoothing with little detail suppression. We have compared four methods: Gaussian smoothing (linear), two-dimensional least-squares smoothing (linear), two-dimensional least-squares bounding (nonlinear), and two-dimensional median smoothing (nonlinear). The two dimensional least-squares procedures have yielded the most satisfactorily enhanced images, with the median smoothers providing quite good images, even in the presence of widely aberrant points
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...
Smooth Adaptation by Sigmoid Shrinkage
Directory of Open Access Journals (Sweden)
Atto AbdourrahmaneM
2009-01-01
Full Text Available This paper addresses the properties of a subclass of sigmoid-based shrinkage functions: the non zeroforcing smooth sigmoid-based shrinkage functions or SigShrink functions. It provides a SURE optimization for the parameters of the SigShrink functions. The optimization is performed on an unbiased estimation risk obtained by using the functions of this subclass. The SURE SigShrink performance measurements are compared to those of the SURELET (SURE linear expansion of thresholds parameterization. It is shown that the SURE SigShrink performs well in comparison to the SURELET parameterization. The relevance of SigShrink is the physical meaning and the flexibility of its parameters. The SigShrink functions performweak attenuation of data with large amplitudes and stronger attenuation of data with small amplitudes, the shrinkage process introducing little variability among data with close amplitudes. In the wavelet domain, SigShrink is particularly suitable for reducing noise without impacting significantly the signal to recover. A remarkable property for this class of sigmoid-based functions is the invertibility of its elements. This propertymakes it possible to smoothly tune contrast (enhancement, reduction.
Pioline, Boris
2015-01-01
In $D=4,N=2$ theories on $R^{3,1}$, the index receives contributions not only from single-particle BPS states, counted by the BPS indices, but also from multi-particle states made of BPS constituents. In a recent work [arXiv:1406.2360], a general formula expressing the index in terms of the BPS indices was proposed, which is smooth across walls of marginal stability and reproduces the expected single-particle contributions. In this note, I analyze the two-particle contributions predicted by this formula, and show agreement with the spectral asymmetry of the continuum of scattering states in the supersymmetric quantum mechanics of two non-relativistic, mutually non-local dyons. This provides a physical justification for the error function profile used in the mathematics literature on indefinite theta series, and in the physics literature on black hole partition functions.
Lensing smoothing of BAO wiggles
Di Dio, Enea
2016-01-01
We study non--perturbatively the effect of the deflection angle on the BAO wiggles of the matter power spectrum in real space. We show that from redshift z~2 this introduces a dispersion of roughly 1 Mpc at BAO scale, which corresponds approximately to a 1% effect. The lensing effect induced by the deflection angle, which is completely geometrical and survey independent, smears out the BAO wiggles. The effect on the power spectrum amplitude at BAO scale is about 0.1% for z~2 and 0.2% for z~4. We compare the smoothing effects induced by the lensing potential and non--linear structure formation, showing that the two effects become comparable at z~4, while the lensing effect dominates for sources at higher redshifts. We note that this effect is not accounted through BAO reconstruction techniques.
Learning Smooth Pattern Transformation Manifolds
Vural, Elif
2011-01-01
Manifold models provide low-dimensional representations that are useful for processing and analyzing data in a transformation-invariant way. In this paper, we study the problem of learning smooth pattern transformation manifolds from image sets that represent observations of geometrically transformed signals. In order to construct a manifold, we build a representative pattern whose transformations accurately fit various input images. We examine two objectives of the manifold building problem, namely, approximation and classification. For the approximation problem, we propose a greedy method that constructs a representative pattern by selecting analytic atoms from a continuous dictionary manifold. We present a DC (Difference-of-Convex) optimization scheme that is applicable to a wide range of transformation and dictionary models, and demonstrate its application to transformation manifolds generated by rotation, translation and anisotropic scaling of a reference pattern. Then, we generalize this approach to a s...
Smoothed Particle Hydrodynamics in Astrophysics
Springel, Volker
2011-01-01
This review discusses Smoothed Particle Hydrodynamics (SPH) in the astrophysical context, with a focus on inviscid gas dynamics. The particle-based SPH technique allows an intuitive and simple formulation of hydrodynamics that has excellent conservation properties and can be coupled to self-gravity easily and highly accurately. The Lagrangian character of SPH allows it to automatically adjust its resolution to the clumping of matter, a property that makes the scheme ideal for many applications in astrophysics, where often a large dynamic range in density is encountered. We discuss the derivation of the basic SPH equations in their modern formulation, and give an overview about extensions of SPH developed to treat physics such as radiative transfer, thermal conduction, relativistic dynamics or magnetic fields. We also briefly describe some of the most important applications areas of SPH in astrophysical research. Finally, we provide a critical discussion of the accuracy of SPH for different hydrodynamical prob...
Resolution of smooth group actions
Albin, Pierre
2010-01-01
A refined form of the `Folk Theorem' that a smooth action by a compact Lie group can be (canonically) resolved, by iterated blow up, to have unique isotropy type is proved in the context of manifolds with corners. This procedure is shown to capture the simultaneous resolution of all isotropy types in a `resolution structure' consisting of equivariant iterated fibrations of the boundary faces. This structure projects to give a similar resolution structure for the quotient. In particular these results apply to give a canonical resolution of the radial compactification, to a ball, of any finite dimensional representation of a compact Lie group; such resolutions of the normal action of the isotropy groups appear in the boundary fibers in the general case.
Radial smoothing and closed orbit
International Nuclear Information System (INIS)
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)
Smooth halos in the cosmic web
Gaite, Jose
2014-01-01
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 equality 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 $N$-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.
Smooth Crossed Products of Rieffel's Deformations
Neshveyev, Sergey
2014-03-01
Assume is a Fréchet algebra equipped with a smooth isometric action of a vector group V, and consider Rieffel's deformation of . We construct an explicit isomorphism between the smooth crossed products and . When combined with the Elliott-Natsume-Nest isomorphism, this immediately implies that the periodic cyclic cohomology is invariant under deformation. Specializing to the case of smooth subalgebras of C*-algebras, we also get a simple proof of equivalence of Rieffel's and Kasprzak's approaches to deformation.
Exponential smoothing methods in pension funding
Owadally, M. I; Haberman, S
2003-01-01
'Smoothed-market' methods are used by actuaries, when they value pension plan assets, in order to dampen the volatility in contribution rates recommended to plan sponsors. A method involving exponential smoothing is considered. The dynamics of the pension funding process is investigated in the context of a simple model where asset gains and losses emerge as a result of random rates of investment return and where the gains and losses are spread. It is shown that smoothing market values up to a...
Families in the future: the pursuit of personal autonomy.
Mcdonald, P
1988-12-01
There have been substantial changes in the demography of the family since the early 1970s in Australia. Age at 1st marriage has risen substantially. In 1986, 6.1% of heterosexual couples in Australia were living together. In 1 in 3 marriages today, 1 or both partners have been married before. The percentage of marriages ending in divorce based on annual data increased from 14% in 1971 to 35% in 1986. The birth rate has declined substantially since 1971. In 1986,, 77% of all households were family households, 4% were group households, and 19% were 1-person households. Over 1 in 3 Australian children being born today will spend some time in a 1-parent family before they reach majority. The important measure, however, may not be family structure but the extent of support, both economic and emotional, that the child receives from his or her parents. Similar arguments may be applied to the aged. A 1982 survey showed that among persons aged 15-64 years who had a parent living elsewhere, over 50% had contact with that parent at least once a week. The same survey showed that among aged people requiring help, they were 5 times more likely to receive that help from a family member than from a government agency or from a voluntary agency. A focus on how families function draws attention to the changes in the lives of married women. Labor force participation rates for married women have been steadily increasing for over 50 years. Even in couple families with a child under 5 years old, 40% of the women were in the labor force in 1986. The family changes described above can all be interpreted in terms of the movement to personal autonomy which has characterized the last 20 years. This is especially the case with the increase in age at marriage, the decline of teenage pregnancy, and the rise in the divorce rate. The trend for young couples to live together rather than marry can be seen as an experiment in the pursuit of personal autonomy. The author hypothesizes that people
Smoothing techniques for macromolecular global optimization
Energy Technology Data Exchange (ETDEWEB)
More, J.J.; Wu, Zhijun
1995-09-01
We study global optimization problems that arise in macromolecular modeling, and the solution of these problems via continuation and smoothing. Our results unify and extend the theory associated with the use of the Gaussian transform for smoothing. We show that the, Gaussian transform can be viewed as a special case of a generalized transform and that these generalized transforms share many of the properties of the Gaussian transform. We also show that the smoothing behavior of the generalized transform can be studied in terms of the Fourier transform and that these results indicate that the Gaussian transform has superior smoothing properties.
Predator-prey pursuit-evasion games in structurally complex environments.
Morice, Sylvie; Pincebourde, Sylvain; Darboux, Frédéric; Kaiser, Wilfried; Casas, Jérôme
2013-11-01
Pursuit and evasion behaviors in many predator-prey encounters occur in a geometrically structured environment. The physical structures in the environment impose strong constraints on the perception and behavioral responses of both antagonists. Nevertheless, no experimental or theoretical study has tackled the issue of quantifying the role of the habitat's architecture on the joint trajectories during a predator-prey encounter. In this study, we report the influence of microtopography of forest leaf litter on the pursuit-evasion trajectories of wolf spiders Pardosa sp. attacking the wood cricket Nemobius sylvestris. Fourteen intact leaf litter samples of 1 m × 0.5 m were extracted from an oak-beech forest floor in summer and winter, with later samples having the most recently fallen leaves. Elevation was mapped at a spatial resolution of 0.5 mm using a laser scanner. Litter structuring patterns were identified by height transects and experimental semi-variograms. Detailed analysis of all visible leaf-fragments of one sample enabled us to relate the observed statistical patterns to the underlying geometry of individual elements. Video recording of pursuit-evasion sequences in arenas with flat paper or leaf litter enabled us to estimate attack and fleeing distances as a function of substrate. The compaction index, the length of contiguous flat surfaces, and the experimental variograms showed that the leaf litter was smoother in summer than in winter. Thus, weathering as well as biotic activities compacted and flattened the litter over time. We found good agreement between the size of the structuring unit of leaf litter and the distance over which attack and escape behaviors both were initiated (both ∼3 cm). There was a four-fold topographical effect on pursuit-escape sequences; compared with a flat surface, leaf litter (1) greatly reduced the likelihood of launching a pursuit, (2) reduced pursuit and escape distances by half, (3) put prey and predator on par in
A Pursuit Theory Account for the Perception of Common Motion in Motion Parallax.
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.
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.
Smooth horizons and quantum ripples
Energy Technology Data Exchange (ETDEWEB)
Golovnev, Alexey [Saint Petersburg State University, High Energy Physics Department, Saint-Petersburg (Russian Federation)
2015-05-15
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.)
Smooth horizons and quantum ripples
Golovnev, Alexey
2014-01-01
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 neglection 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 di...
Smoothing of physiological signals. JLIS 01, parabolic smoothing module in real time
International Nuclear Information System (INIS)
In biomedical engineering, signal analysis is generally made after a preliminary software processing called smoothing. This process has the disadvantage of requiring a relatively long processing time. The CAMAC JLIS 01 module gives either the smoothed signal, or the derivative after smoothing, from the digitized signal. The smoothing type is parabolic (seven points) and is carried out in 400ns; the information is defined by eight bits plus sign. The CAMAC module including the DATAWAY connection requires 80 integrated circuits
Mechanotransduction in colonic smooth muscle cells.
Young, S H; Ennes, H S; Mayer, E A
1997-11-15
We evaluated mechanisms which mediate alterations in intracellular biochemical events in response to transient mechanical stimulation of colonic smooth muscle cells. Cultured myocytes from the circular muscle layer of the rabbit distal colon responded to brief focal mechanical deformation of the plasma membrane with a transient increase in intracellular calcium concentration ([Ca2+]i) with peak of 422.7 +/- 43.8 nm above an average resting [Ca2+]i of 104.8 +/- 10.9 nM (n = 57) followed by both rapid and prolonged recovery phases. The peak [Ca2+]i increase was reduced by 50% in the absence of extracellular Ca2+, while the prolonged [Ca2+]i recovery was either abolished or reduced to less than or = 15% of control values. In contrast, no significant effect of gadolinium chloride (100 microM) or lanthanum chloride (25 microM) on either peak transient or prolonged [Ca2+]i recovery was observed. Pretreatment of cells with thapsigargin (1 microM) resulted in a 25% reduction of the mechanically induced peak [Ca2+]i response, while the phospholipase C inhibitor U-73122 had no effect on the [Ca2+]i transient peak. [Ca2+]i transients were abolished when cells previously treated with thapsigargin were mechanically stimulated in Ca2+-free solution, or when Ca2+ stores were depleted by thapsigargin in Ca2+-free solution. Pretreatment with the microfilament disrupting drug cytochalasin D (10 microM) or microinjection of myocytes with an intracellular saline resulted in complete inhibition of the transient. The effect of cytochalasin D was reversible and did not prevent the [Ca2+]i increases in response to thapsigargin. These results suggest a communication, which may be mediated by direct mechanical link via actin filaments, between the plasma membrane and an internal Ca2+ store.
The Pivotal Role of Airway Smooth Muscle in Asthma Pathophysiology
Directory of Open Access Journals (Sweden)
Annaïg Ozier
2011-01-01
Full Text Available Asthma is characterized by the association of airway hyperresponsiveness (AHR, inflammation, and remodelling. The aim of the present article is to review the pivotal role of airway smooth muscle (ASM in the pathophysiology of asthma. ASM is the main effector of AHR. The mechanisms of AHR in asthma may involve a larger release of contractile mediators and/or a lower release of relaxant mediators, an improved ASM cell excitation/contraction coupling, and/or an alteration in the contraction/load coupling. Beyond its contractile function, ASM is also involved in bronchial inflammation and remodelling. Whereas ASM is a target of the inflammatory process, it can also display proinflammatory and immunomodulatory functions, through its synthetic properties and the expression of a wide range of cell surface molecules. ASM remodelling represents a key feature of asthmatic bronchial remodelling. ASM also plays a role in promoting complementary airway structural alterations, in particular by its synthetic function.
Thermal smoothing of rough surfaces in vacuo
Wahl, G.
1986-01-01
The derivation of equations governing the smoothing of rough surfaces, based on Mullins' (1957, 1960, and 1963) theories of thermal grooving and of capillarity-governed solid surface morphology is presented. As an example, the smoothing of a one-dimensional sine-shaped surface is discussed.
Nonparametric (smoothed) likelihood and integral equations
Groeneboom, Piet
2012-01-01
We show that there is an intimate connection between the theory of nonparametric (smoothed) maximum likelihood estimators for certain inverse problems and integral equations. This is illustrated by estimators for interval censoring and deconvolution problems. We also discuss the asymptotic efficiency of the MLE for smooth functionals in these models.
Improved Edge Awareness in Discontinuity Preserving Smoothing
Heinrich, Stuart B
2011-01-01
Discontinuity preserving smoothing is a fundamentally important procedure that is useful in a wide variety of image processing contexts. It is directly useful for noise reduction, and frequently used as an intermediate step in higher level algorithms. For example, it can be particularly useful in edge detection and segmentation. Three well known algorithms for discontinuity preserving smoothing are nonlinear anisotropic diffusion, bilateral filtering, and mean shift filtering. Although slight differences make them each better suited to different tasks, all are designed to preserve discontinuities while smoothing. However, none of them satisfy this goal perfectly: they each have exception cases in which smoothing may occur across hard edges. The principal contribution of this paper is the identification of a property we call edge awareness that should be satisfied by any discontinuity preserving smoothing algorithm. This constraint can be incorporated into existing algorithms to improve quality, and usually ha...
Smoothed dynamics in the central field problem
Santoprete, Manuele
2009-01-01
Consider the motion of a material point of unit mass in a central field determined by a homogeneous potential of the form $(-1/r^{\\alpha})$, $\\alpha>0,$ where $r$ being the distance to the centre of the field. Due to the singularity at $r=0,$ in computer-based simulations, usually, the potential is replaced by a similar potential that is smooth, or at least continuous. In this paper, we compare the global flows given by the smoothed and non-smoothed potentials. It is shown that the two flows are topologically equivalent for $\\alpha < 2,$ while for $\\alpha \\geq 2,$ smoothing introduces fake orbits. Further, we argue that for $\\alpha\\geq 2,$ smoothing should be applied to the amended potential $c/(2r^2)-1/r^{\\alpha},$ where $c$ denotes the angular momentum constant.
Cardiac, Skeletal, and smooth muscle mitochondrial respiration
DEFF Research Database (Denmark)
Park, Song-Young; Gifford, Jayson R; Andtbacka, Robert H I;
2014-01-01
Unlike cardiac and skeletal muscle, little is known about vascular smooth muscle mitochondrial function. Therefore, this study examined mitochondrial respiratory rates in the smooth muscle of healthy human feed arteries and compared with that of healthy cardiac and skeletal muscle. Cardiac......, skeletal, and smooth muscle was harvested from a total of 22 subjects (53±6 yrs) and mitochondrial respiration assessed in permeabilized fibers. Complex I+II, state 3 respiration, an index of oxidative phosphorylation capacity, fell progressively from cardiac, skeletal, to smooth muscle (54±1; 39±4; 15......±1 pmol•s(-1)•mg (-1), pmitochondrial density, also fell progressively from cardiac, skeletal, to smooth muscle (222±13; 115±2; 48±2 umol•g(-1)•min(-1), p
Smooth maps from clumpy data Covariance analysis
Lombardi, M; Lombardi, Marco; Schneider, Peter
2002-01-01
Interpolation techniques play a central role in Astronomy, where one often needs to smooth irregularly sampled data into a smooth map. In a previous article (Lombardi & Schneider 2001), we have considered a widely used smoothing technique and we have evaluated the expectation value of the smoothed map under a number of natural hypotheses. Here we proceed further on this analysis and consider the variance of the smoothed map, represented by a two-point correlation function. We show that two main sources of noise contribute to the total error budget and we show several interesting properties of these two noise terms. The expressions obtained are also specialized to the limiting cases of low and high densities of measurements. A number of examples are used to show in practice some of the results obtained.
Benefit Evaluation Model of Small Watershed Control Based on Projection Pursuit
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
A projection pursuit model is presented in this paper for comprehensive evaluation of benefits of small watershed control. By using the model ,small watershed control samples with many benefit evaluation indexes can be synthesized projective values with one dimension. The samples can be naturally evaluated according to the projective values. The parameters of the model is optimized by using real coding beased accelerating genetic aglrothm,which overcomes the shortcomings of large computation amount and difficulty of computer programming in traditional projection prusuit methods,and provides a new way for wide applications of projection pursuit technique to different evaluation problems in agricultural systems engineering.
Institute of Scientific and Technical Information of China (English)
Zhao Ruizhen; Ren Xiaoxin; Han Xuelian; Hu Shaohai
2012-01-01
Sparsity Adaptive Matching Pursuit (SAMP) algorithm is a widely used reconstruction algorithm for compressive sensing in the case that the sparsity is unknown.In order to match the sparsity more accurately,we presented an improved SAMP algorithm based on Regularized Backtracking (SAMP-RB).By adapting a regularized backtracking step to SAMP algorithm in each iteration stage,the proposed algorithm can flexibly remove the inappropriate atoms.The experimental results show that SAMP-RB reconstruction algorithm greatly improves SAMP algorithm both in reconstruction quality and computational time.It has better reconstruction efficiency than most of the available matching pursuit algorithms.
Reduction of snapshots for MIMO radar detection by block/group orthogonal matching pursuit
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.
Current economic downturn and supply chain : The significance of demand and inventory smoothing
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
Johnson, Peter R A; Burgess, Janette K; Underwood, P Anne; Au, Wendy; Poniris, Maree H; Tamm, Michael; Ge, Qi; Roth, Michael; Black, Judith L
2004-01-01
BACKGROUND: Airway remodeling is a key feature of persistent asthma and includes alterations in the extracellular matrix protein profile around the airway smooth muscle (ASM) and hyperplasia of the ASM. We have previously shown that nonasthmatic ASM cells in culture produce a range of extracellular
International Nuclear Information System (INIS)
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)
Hyvonen, Katriina; Feldt, Taru; Tolvanen, Asko; Kinnunen, Ulla
2010-01-01
The relation of the core components of the Effort-Reward Imbalance model (ERI; Siegrist, 1996) to goal pursuit was investigated. Goal pursuit was studied through categories of goal contents--competency, progression, well-being, job change, job security, organization, finance, or no work goal--based on the personal work goals of managers (Hyvonen,…
In pursuit of resilience: stress, epigenetics, and brain plasticity.
McEwen, Bruce S
2016-06-01
The brain is the central organ for adaptation to experiences, including stressors, which are capable of changing brain architecture as well as altering systemic function through neuroendocrine, autonomic, immune, and metabolic systems. Because the brain is the master regulator of these systems, as well as of behavior, alterations in brain function by chronic stress can have direct and indirect effects on cumulative allostatic overload, which refers to the cost of adaptation. There is much new knowledge on the neural control of systemic physiology and the feedback actions of physiologic mediators on brain regions regulating higher cognitive function, emotional regulation, and self-regulation. The healthy brain has a considerable capacity for resilience, based upon its ability to respond to interventions designed to open "windows of plasticity" and redirect its function toward better health. As a result, plasticity-facilitating treatments should be given within the framework of a positive behavioral intervention; negative experiences during this window may even make matters worse. Indeed, there are no magic bullets and drugs cannot substitute for targeted interventions that help an individual become resilient, of which mindfulness-based stress reduction and meditation are emerging as useful tools. PMID:26919273
Dual-support Smoothed Particle Hydrodynamics
Ren, Huilong; Zhuang, Xiaoying; Rabczuk, Timon
2016-01-01
In this paper we develop a dual-support smoothed particle hydrodynamics (DS-SPH) that naturally satisfies the conservation of momentum, angular momentum and energy when the varying smoothing length is utilized. The DS-SPH is based on the concept of dual-support, which is introduced to consider the unbalanced interactions between the particles with different smoothing lengths. Our DS-SPH formulation can be implemented in traditional SPH with little changes and improve the computational efficiency. Several numerical examples are presented to demonstrate the capability of the method.
Bifurcations of non-smooth systems
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.
Smoothed dynamics in the central field problem
Santoprete, Manuele; Stoica, Cristina
2009-01-01
Consider the motion of a material point of unit mass in a central field determined by a homogeneous potential of the form $(-1/r^{\\alpha})$, $\\alpha>0,$ where $r$ being the distance to the centre of the field. Due to the singularity at $r=0,$ in computer-based simulations, usually, the potential is replaced by a similar potential that is smooth, or at least continuous. In this paper, we compare the global flows given by the smoothed and non-smoothed potentials. It is shown that the two flows ...
Kong, Xiaoqing; Chakraverty, Devasmita; Jeffe, Donna B.; Andriole, Dorothy A.; Wathington, Heather D.; Tai, Robert H.
2013-01-01
This exploratory qualitative study investigated how doctoral students reported their personal and professional interaction experiences that they believed might facilitate or impede their academic pursuits in biomedical research. We collected 19 in-depth interviews with doctoral students in biomedical research from eight universities, and we based…
The "Negotiated Space" of University Researchers' Pursuit of a Research Agenda
Luukkonen, Terttu; Thomas, Duncan A.
2016-01-01
The paper introduces a concept of a "negotiated space" to describe university researchers' attempts to balance pragmatically, continually and dynamically over time, their own agency and autonomy in the selection of research topics and pursuit of scientific research to filter out the explicit steering and tacit signals of external…
The Tenacious Goal Pursuit and Flexible Goal Adjustment Scales : A Validation Study
Henselmans, Inge; Fleer, Joke; van Sonderen, Eric; Smink, Ans; Sanderman, Robbert; Ranchor, Adelita V.
2011-01-01
The flexible goal adjustment (FLEX) and tenacious goal pursuit (TEN) scales are used regularly in aging research. The current study examined their validity in a sample of 517 women (30-75 years) in multiple ways. Overall, the findings show that the scales do not clearly distinguish between FLEX and
Dynamics of the echolocation beam during prey pursuit in aerial hawking bats.
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. PMID:26080398
38 CFR 21.314 - Pursuit of training under special conditions.
2010-07-01
... is required to pursue a rehabilitation program at a rate which meets the requirement for full- or... rehabilitation program at a lesser rate, if such pursuit is a part of the veteran's plan. Subsistence allowance... AFFAIRS (CONTINUED) VOCATIONAL REHABILITATION AND EDUCATION Vocational Rehabilitation and Employment...
Curry, Marnie W.
2012-01-01
In the ideal, reciprocity in qualitative inquiry occurs when there is give-and-take between researchers and the researched; however, the demands of the academy and resource constraints often make the pursuit of reciprocity difficult. Drawing on two video-based, qualitative studies in which researchers utilized video records as resources to enhance…
Hardman, Randy K.; Berrett, Michael E.; Richards, P. Scott
2003-01-01
Authors describe ten false beliefs that women with eating disorders may hold. They explain how the pursuit of these beliefs can prevent the women from connecting with God and with others in genuine ways. They also suggest some therapeutic strategies that may help women with eating disorders find a healing and helpful spiritual perspective.…
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…
A* Orthogonal Matching Pursuit: Best-First Search for Compressed Sensing Signal Recovery
Karahanoglu, Nazim Burak
2010-01-01
Compressed sensing is a recently developing area which is interested in reconstruction of sparse signals acquired in reduced dimensions. Acquiring the data with a small number of samples makes the reconstruction problem under-determined. The required solution is the one with minimum $l_0$ norm due to sparsity, however it is not practical to solve the $l_0$ minimization problem. Some methods, such as Basis Pursuit (BP) propose casting the problem as an $l_1$ minimization. Greedy pursuit algorithms, such as Orthogonal Matching Pursuit (OMP) and Subspace Pursuit (SP), perform a greedy search among the vectors in the basis with the goal of stagewise constrained minimization of the residual error. This manuscript proposes a new semi-greedy algorithm which employs a best-first search technique, the A* search. This approach searches for the solution on several paths of a search tree, where the paths are evaluated and extended according to some cost function, which should be carefully selected to compensate for paths...
Bijleveld, E.H.; Custers, R.; Aarts, H.A.G.
2012-01-01
When in pursuit of rewards, humans weigh the value of potential rewards against the amount of effort that is required to attain them. Although previous research has generally conceptualized this process as a deliberate calculation, recent work suggests that rudimentary mechanisms operating without c
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…
The Role of Intrinsic Motivation in the Academic Pursuits of Nontraditional Students
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…
When goal pursuit fails: The functions of counterfactual thought in intention formation
Epstude, K.; Roese, N.J.
2011-01-01
Counterfactual thoughts predominantly occur in response to failed goal pursuit. The primary function of self-related counterfactuals seems to be correction of specific behaviors and preparation for future successful goal attainment. In the present article we describe a model that outlines this view
The Role of an Epistemology of Inclusivity on the Pursuit of Social Justice: A Case Study
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…
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
Estimations of the smoothing operator response characteristics
Yatskiv, Y. S.
1974-01-01
The mean response characteristic of the graphical smoothing method is discussed. The method is illustrated by analysis of latitude observations at Washington from 1915.9 to 1941.0. Spectral density, frequency distribution, and distribution functions are also discussed.
Fractional Smoothness of Some Stochastic Integrals
Institute of Scientific and Technical Information of China (English)
Peng XIE; Xi Cheng ZHANG
2007-01-01
We study the fractional smoothness in the sense of Malliavin calculus of stochastic integralsof the form ∫10 φ(Xs)d Xs,where Xs is a semimartingale and φ belongs to some fractional Sobolev spaceover R.
Integrated Groups and Smooth Distribution Groups
Institute of Scientific and Technical Information of China (English)
Pedro J. MIANA
2007-01-01
In this paper, we prove directly that α-times integrated groups define algebra homo-morphisms. We also give a theorem of equivalence between smooth distribution groups and α-times integrated groups.
Smooth surfaces from rational bilinear patches
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.
Asphericity structures, smooth functors, and fibrations
Maltsiniotis, G
2009-01-01
The aim of this paper is to generalize Grothendieck's theory of smooth functors in order to include within this framework the theory of fibered categories. We obtain in particular a new characterization of fibered categories.
Spectral sequences in smooth generalized cohomology
Grady, Daniel
2016-01-01
We consider spectral sequences in smooth generalized cohomology theories, including differential generalized cohomology theories. The main differential spectral sequences will be of the Atiyah-Hirzebruch (AHSS) type, where we provide a filtration by the Cech resolution of smooth manifolds. This allows for systematic study of torsion in differential cohomology. We apply this in detail to smooth Deligne cohomology, differential topological complex K-theory, and to a smooth extension of integral Morava K-theory that we introduce. In each case we explicitly identify the differentials in the corresponding spectral sequences, which exhibit an interesting and systematic interplay between (refinement of) classical cohomology operations, operations involving differential forms, and operations on cohomology with U(1) coefficients.
Kalman Filter Desing, Smoothing and Analysis
2001-01-01
Thesis is based on three different aspects of Kalman filtering. >Kalman filters for navigation. Investigate the difference between a Extended Kalman Filter and a Linearized Kalman Filter with feedback. And show how different system models relate to these Kalman Filters when implemented in a filter. >Smoothing. Investigate how much there is to be gained from smoothing. We will only look at the fixed-interval smoother, using the method of forward and backward filtering. ...
Rubber friction on (apparently) smooth lubricated surfaces
Energy Technology Data Exchange (ETDEWEB)
Mofidi, M; Prakash, B [Division of Machine Elements, Luleaa University of Technology, Luleaa SE-97187 (Sweden); Persson, B N J [IFF, FZ-Juelich, 52425 Juelich (Germany); Albohr, O [Pirelli Deutschland AG, 64733 Hoechst/Odenwald, Postfach 1120 (Germany)
2008-02-27
We study rubber sliding friction on hard lubricated surfaces. We show that even if the hard surface appears smooth to the naked eye, it may exhibit short-wavelength roughness, which may make the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the counterface surface asperities. The results presented are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.
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...... 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’....
Function spaces of variable smoothness and integrability
Diening, Lars; Hästö, Peter; Roudenko, Svetlana
2007-01-01
In this article we introduce Triebel--Lizorkin spaces with variable smoothness and integrability. Our new scale covers spaces with variable exponent as well as spaces of variable smoothness that have been studied in recent years. Vector-valued maximal inequalities do not work in the generality which we pursue, and an alternate approach is thus developed. Applying it, we give molecular and atomic decomposition results and show that our space is well-defined, i.e., independent of the choice of ...
Lennart Hilbert; Genevieve Bates; Roman, Horia N.; Jenna L Blumenthal; Zitouni, Nedjma B.; Apolinary Sobieszek; Mackey, Michael C.; Anne-Marie Lauzon
2013-01-01
The proteins involved in smooth muscle's molecular contractile mechanism - the anti-parallel motion of actin and myosin filaments driven by myosin heads interacting with actin - are found as different isoforms. While their expression levels are altered in disease states, their relevance to the mechanical interaction of myosin with actin is not sufficiently understood. Here, we analyzed in vitro actin filament propulsion by smooth muscle myosin for [Formula: see text]-actin ([Formula: see text...
Beam-smoothing investigation on Heaven I
Xiang, Yi-huai; Gao, Zhi-xing; Tong, Xiao-hui; Dai, Hui; Tang, Xiu-zhang; Shan, Yu-sheng
2007-01-01
Directly driven targets for inertial confinement fusion (ICF) require laser beams with extremely smooth irradiance profiles to prevent hydrodynamic instabilities that destroy the spherical symmetry of the target during implosion. Such instabilities can break up and mix together the target's wall and fuel material, preventing it from reaching the density and temperature required for fusion ignition. 1,2 Measurements in the equation of state (EOS) experiments require laser beams with flat-roofed profiles to generate uniform shockwave 3. Some method for beam smooth, is thus needed. A technique called echelon-free induced spatial incoherence (EFISI) is proposed for producing smooth target beam profiles with large KrF lasers. The idea is basically an image projection technique that projects the desired time-averaged spatial profile onto the target via the laser system, using partially coherent broadband lighe. Utilize the technique, we developing beam- smoothing investigation on "Heaven I". At China Institute of Atomic Energy , a new angular multiplexing providing with beam-smoothing function has been developed, the total energy is 158J, the stability of energy is 4%, the pulse duration is 25ns, the effective diameter of focusing spot is 400um, and the ununiformity is about 1.6%, the power density on the target is about 3.7×10 12W/cm2. At present, the system have provided steady and smooth laser irradiation for EOS experiments.
Nonequilibrium flows with smooth particle applied mechanics
Energy Technology Data Exchange (ETDEWEB)
Kum, O.
1995-07-01
Smooth particle methods are relatively new methods for simulating solid and fluid flows through they have a 20-year history of solving complex hydrodynamic problems in astrophysics, such as colliding planets and stars, for which correct answers are unknown. The results presented in this thesis evaluate the adaptability or fitness of the method for typical hydrocode production problems. For finite hydrodynamic systems, boundary conditions are important. A reflective boundary condition with image particles is a good way to prevent a density anomaly at the boundary and to keep the fluxes continuous there. Boundary values of temperature and velocity can be separately controlled. The gradient algorithm, based on differentiating the smooth particle expression for (u{rho}) and (T{rho}), does not show numerical instabilities for the stress tensor and heat flux vector quantities which require second derivatives in space when Fourier`s heat-flow law and Newton`s viscous force law are used. Smooth particle methods show an interesting parallel linking to them to molecular dynamics. For the inviscid Euler equation, with an isentropic ideal gas equation of state, the smooth particle algorithm generates trajectories isomorphic to those generated by molecular dynamics. The shear moduli were evaluated based on molecular dynamics calculations for the three weighting functions, B spline, Lucy, and Cusp functions. The accuracy and applicability of the methods were estimated by comparing a set of smooth particle Rayleigh-Benard problems, all in the laminar regime, to corresponding highly-accurate grid-based numerical solutions of continuum equations. Both transient and stationary smooth particle solutions reproduce the grid-based data with velocity errors on the order of 5%. The smooth particle method still provides robust solutions at high Rayleigh number where grid-based methods fails.
Turbulent flow in smooth and rough pipes.
Allen, J J; Shockling, M A; Kunkel, G J; Smits, A J
2007-03-15
Recent experiments at Princeton University have revealed aspects of smooth pipe flow behaviour that suggest a more complex scaling than previously noted. In particular, the pressure gradient results yield a new friction factor relationship for smooth pipes, and the velocity profiles indicate the presence of a power-law region near the wall and, for Reynolds numbers greater than about 400x103 (R+>9x103), a logarithmic region further out. New experiments on a rough pipe with a honed surface finish with krms/D=19.4x10-6, over a Reynolds number range of 57x103-21x106, show that in the transitionally rough regime this surface follows an inflectional friction factor relationship rather than the monotonic relationship given in the Moody diagram. Outer-layer scaling of the mean velocity data and streamwise turbulence intensities for the rough pipe show excellent collapse and provide strong support for Townsend's outer-layer similarity hypothesis for rough-walled flows. The streamwise rough-wall spectra also agree well with the corresponding smooth-wall data. The pipe exhibited smooth behaviour for ks+ < or =3.5, which supports the suggestion that the original smooth pipe was indeed hydraulically smooth for ReD< or =24x106. The relationship between the velocity shift, DeltaU/utau, and the roughness Reynolds number, ks+, has been used to generalize the form of the transition from smooth to fully rough flow for an arbitrary relative roughness krms/D. These predictions apply for honed pipes when the separation of pipe diameter to roughness height is large, and they differ significantly from the traditional Moody curves.
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.
Smoothing methods in biometry: a historic review
Directory of Open Access Journals (Sweden)
Schimek, Michael G.
2005-06-01
Full Text Available In Germany around 25 years ago nonparametric smoothing methods have found their way into statistics and with some delay also into biometry. In the early 1980's there has been what one might call a boom in theoretical and soon after also in computational statistics. The focus was on univariate nonparametric methods for density and curve estimation. For biometry however smoothing methods became really interesting in their multivariate version. This 'change of dimensionality' is still raising open methodological questions. No wonder that the simplifying paradigm of additive regression, realized in the generalized additive models (GAM, has initiated the success story of smoothing techniques starting in the early 1990's. In parallel there have been new algorithms and important software developments, primarily in the statistical programming languages S and R. Recent developments of smoothing techniques can be found in survival analysis, longitudinal analysis, mixed models and functional data analysis, partly integrating Bayesian concepts. All new are smoothing related statistical methods in bioinformatics. In this article we aim not only at a general historical overview but also try to sketch activities in the German-speaking world. Moreover, the current situation is critically examined. Finally a large number of relevant references is given.
Turbulent flow in smooth and rough pipes.
Allen, J J; Shockling, M A; Kunkel, G J; Smits, A J
2007-03-15
Recent experiments at Princeton University have revealed aspects of smooth pipe flow behaviour that suggest a more complex scaling than previously noted. In particular, the pressure gradient results yield a new friction factor relationship for smooth pipes, and the velocity profiles indicate the presence of a power-law region near the wall and, for Reynolds numbers greater than about 400x103 (R+>9x103), a logarithmic region further out. New experiments on a rough pipe with a honed surface finish with krms/D=19.4x10-6, over a Reynolds number range of 57x103-21x106, show that in the transitionally rough regime this surface follows an inflectional friction factor relationship rather than the monotonic relationship given in the Moody diagram. Outer-layer scaling of the mean velocity data and streamwise turbulence intensities for the rough pipe show excellent collapse and provide strong support for Townsend's outer-layer similarity hypothesis for rough-walled flows. The streamwise rough-wall spectra also agree well with the corresponding smooth-wall data. The pipe exhibited smooth behaviour for ks+ pipe was indeed hydraulically smooth for ReDpipes when the separation of pipe diameter to roughness height is large, and they differ significantly from the traditional Moody curves. PMID:17244585
Smooth muscle actin and myosin expression in cultured airway smooth muscle cells.
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.
Archetypal oscillator for smooth and discontinuous dynamics
Cao, Qingjie; Wiercigroch, Marian; Pavlovskaia, Ekaterina E.; Grebogi, Celso; T. Thompson, J. Michael
2006-10-01
We propose an archetypal system to investigate transitions from smooth to discontinuous dynamics. In the smooth regime, the system bears significant similarities to the Duffing oscillator, exhibiting the standard dynamics governed by the hyperbolic structure associated with the stationary state of the double well. At the discontinuous limit, however, there is a substantial departure in the dynamics from the standard one. In particular, the velocity flow suffers a jump in crossing from one well to another, caused by the loss of local hyperbolicity due to the collapse of the stable and unstable manifolds of the stationary state. In the presence of damping and external excitation, the system has coexisting attractors and also a chaotic saddle which becomes a chaotic attractor when a smoothness parameter drops to zero. This attractor can bifurcate to a high-period periodic attractor or a chaotic sea with islands of quasiperiodic attractors depending on the strength of damping.
Adsorption on smooth electrodes: A radiotracer study
International Nuclear Information System (INIS)
Adsorption on solids is a complicated process and in most cases, occurs as the early stage of other more complicated processes, i.e. chemical reactions, electrooxidation, electroreduction. The research reported here combines the electroanalytical method, cyclic voltammetry, and the use of radio-labeled isotopes, soft beta emitters, to study adsorption processes at smooth electrodes. The in-situ radiotracer method is highly anion (molecule) specific and provides information on the structure and composition of the electric double layer. The emphasis of this research was on studying adsorption processes at smooth electrodes of copper, gold, and platinum. The application of the radiotracer method to these smooth surfaces have led to direct in-situ measurements from which surface coverage was determined; anions and molecules were identified; and weak interactions of adsorbates with the surface of the electrodes were readily monitored. 179 refs
Institute of Scientific and Technical Information of China (English)
Lin Wei; Tian Zheng; Wen Xianbin
2003-01-01
The Wavelet-Domain Projection Pursuit Learning Network (WDPPLN) is proposedfor restoring degraded image. The new network combines the advantages of both projectionpursuit and wavelet shrinkage. Restoring image is very difficult when little is known about apriori knowledge for multisource degraded factors. WDPPLN successfully resolves this problemby separately processing wavelet coefficients and scale coefficients. Parameters in WDPPLN,which are used to simulate degraded factors, are estimated via WDPPLN training, using scalecoefficients. Also, WDPPLN uses soft-threshold of wavelet shrinkage technique to suppress noisein three high frequency subbands. The new method is compared with the traditional methodsand the Projection Pursuit Learning Network (PPLN) method. Experimental results demonstratethat it is an effective method for unsupervised restoring degraded image.
Matching pursuit and source deflation for sparse EEG/MEG dipole moment estimation.
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. PMID:23529074
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...
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...
Mass enhances speed but diminishes turn capacity in terrestrial pursuit predators.
Wilson, Rory P; Griffiths, Iwan W; Mills, Michael G L; Carbone, Chris; Wilson, John W; Scantlebury, David M
2015-08-07
The dynamics of predator-prey pursuit appears complex, making the development of a framework explaining predator and prey strategies problematic. We develop a model for terrestrial, cursorial predators to examine how animal mass modulates predator and prey trajectories and affects best strategies for both parties. We incorporated the maximum speed-mass relationship with an explanation of why larger animals should have greater turn radii; the forces needed to turn scale linearly with mass whereas the maximum forces an animal can exert scale to a 2/3 power law. This clarifies why in a meta-analysis, we found a preponderance of predator/prey mass ratios that minimized the turn radii of predators compared to their prey. It also explained why acceleration data from wild cheetahs pursuing different prey showed different cornering behaviour with prey type. The outcome of predator prey pursuits thus depends critically on mass effects and the ability of animals to time turns precisely.
Toward realistic pursuit-evasion using a roadmap-based approach
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.
Cinematographic analysis of vascular smooth muscle cell interactions with extracellular matrix.
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.
The Pursuit of Sustainable Competitive Advantage : A Profile of the Starbucks Corporation
White, Benjamin; Moraschinelli, Ettore
2009-01-01
Title: The Pursuit of Sustainable Competitive Advantage – A Profile of the Starbucks Corporation Authors: Benjamin Adam White & Ettore Moraschinelli Advisor: Jean-Charles Languilaire Date: 2009 May 29 Program: International Business and Entrepreneurship Purpose: To study sustainable competitive advantages using Starbucks as a case study. Methods: The qualitative method was utilized to collect the secondary data used in this type of thesis, being a case study. This approach applied to both...
In Pursuit of Excellence: A Student Guide to Elite Sports Development
Michael Hill
2007-01-01
DESCRIPTION This book is about how it is possible to achieve the excellence in sport in modern times. PURPOSE To cover the past of competitive sport of today as well as discussing current issues in sport such as drugs. The comparison of elite sporting methods in leading sport countries is also included. AUDIENCE Students in the field and anybody interested in modern sports especially in the history of it. FEATURES A comprehensive introduction about the pursuit of excellence in sport, covering...
A BRIEF TALK ON AMERICAN CULTURAL VALUES: REFLECTED ON THE MOVIE THE PURSUIT OF HAPPINESS
Directory of Open Access Journals (Sweden)
Temmy Temmy
2009-05-01
Full Text Available America as one of world’s biggest developed countries has a very strong influence on globaleconomy, politics, education, science, and military. America is also one of teaching Chinese as aforeign language destinations, therefore understanding American cultural values is very important.Article represents American cultural values based on a true story movie "The pursuit of Happiness".Research method applied was library research. It can be concluded that the characters, setting, andconflicts really presented the characteristics of American society.
Money and the Pursuit of Happiness: In Good Times and Bad
Erika Rasure
2012-01-01
Money and the Pursuit of Happiness: In Good Times and Bad is a consumer’s introductory guide of personal reflection with money. The book’s author discusses how to develop a foundational relationship with one’s financial self in an effort to establish ongoing happiness and life satisfaction. The book can be an effective resource recommended by financial and mental health practitioners to clients. The book can help introduce or guide ongoing discussions about who an individual is in relati...
Pursuit of communal values in an agentic manner: a way to happiness?
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, competenc...
PROJECTION-PURSUIT BASED PRINCIPAL COMPONENT ANALYSIS: A LARGE SAMPLE THEORY
Institute of Scientific and Technical Information of China (English)
Jian ZHANG
2006-01-01
The principal component analysis (PCA) is one of the most celebrated methods in analysing multivariate data. An effort of extending PCA is projection pursuit (PP), a more general class of dimension-reduction techniques. However, the application of this extended procedure is often hampered by its complexity in computation and by lack of some appropriate theory. In this paper, by use of the empirical processes we established a large sample theory for the robust PP estimators of the principal components and dispersion matrix.
A New Performance Guarantee for Orthogonal Matching Pursuit Using Mutual Coherence
Emadi, Mohammad; Miandji, Ehsan; Unger, Jonas; Afshari, Ehsan
2016-01-01
In this paper we present a new coherence-based performance guarantee for the Orthogonal Matching Pursuit (OMP) algorithm. An upper bound for the probability of correctly identifying the support of a sparse signal with additive white Gaussian noise is derived. Compared to previous work, the new bound takes into account the signal parameters such as dynamic range, noise variance, and sparsity. Numerical simulations show significant improvements over previous work.
Smoothness, Low-Noise and Fast Rates
Srebro, Nathan; Tewari, Ambuj
2010-01-01
We establish am excess risk bound of order $H \\Rad_n^2 + \\sqrt{H L^*}\\Rad_n$ for ERM with an H-smooth loss function and a hypothesis class with Rademacher complexity $\\Rad_n$, where $L^*$ is the best risk achievable by the hypothesis class. For typical hypothesis classes where $\\Rad_n = \\sqrt{R/n}$, this translates to a learning rate of order $RH/n$ in the separable ($L^*=0$) case and $RH/n + \\sqrt{L^* RH/n}$ more generally. We also provide similar guarantees for online and stochastic convex optimization of a smooth non-negative objective.
Production of super-smooth articles
Energy Technology Data Exchange (ETDEWEB)
Duchane, D.V.
1981-05-29
Super-smooth rounded or formed articles made of thermoplastic materials including various poly(methyl methacrylate) or acrylonitrile-butadiene-styrene copolymers are produced by immersing the articles into a bath, the composition of which is slowly changed with time. The starting composition of the bath is made up of at least one solvent for the polymer and a diluent made up of at least one nonsolvent for the polymer and optional materials which are soluble in the bath. The resulting extremely smooth articles are useful as mandrels for laser fusion and should be useful for a wide variety of other purposes, for example lenses.
Smooth models for the Coulomb potential
González-Espinoza, Cristina E; Karwowski, Jacek; Savin, Andreas
2016-01-01
Smooth model potentials with parameters selected to reproduce the spectrum of one-electron atoms are used to approximate the singular Coulomb potential. Even when the potentials do not mimic the Coulomb singularity, much of the spectrum is reproduced within the chemical accuracy. For the Hydrogen atom, the smooth approximations to the Coulomb potential are more accurate for higher angular momentum states. The transferability of the model potentials from an attractive interaction (Hydrogen atom) to a repulsive one (Harmonium and the uniform electron gas) is discussed.
Steve Wolverton
2010-01-01
Review of The Pursuit of Ecotopia: Lessons from Indigenous and Traditional Societies for the Human Ecology of Our Modern World. Eugene N. Anderson. 2010. Praeger Publishers, Santa Barbara. Pp. 251. $44.95 (Hardcover). ISBN 0313381305.
Research on evaluating water resource resilience based on projection pursuit classification model
Liu, Dong; Zhao, Dan; Liang, Xu; Wu, Qiuchen
2016-03-01
Water is a fundamental natural resource while agriculture water guarantees the grain output, which shows that the utilization and management of water resource have a significant practical meaning. Regional agricultural water resource system features with unpredictable, self-organization, and non-linear which lays a certain difficulty on the evaluation of regional agriculture water resource resilience. The current research on water resource resilience remains to focus on qualitative analysis and the quantitative analysis is still in the primary stage, thus, according to the above issues, projection pursuit classification model is brought forward. With the help of artificial fish-swarm algorithm (AFSA), it optimizes the projection index function, seeks for the optimal projection direction, and improves AFSA with the application of self-adaptive artificial fish step and crowding factor. Taking Hongxinglong Administration of Heilongjiang as the research base and on the basis of improving AFSA, it established the evaluation of projection pursuit classification model to agriculture water resource system resilience besides the proceeding analysis of projection pursuit classification model on accelerating genetic algorithm. The research shows that the water resource resilience of Hongxinglong is the best than Raohe Farm, and the last 597 Farm. And the further analysis shows that the key driving factors influencing agricultural water resource resilience are precipitation and agriculture water consumption. The research result reveals the restoring situation of the local water resource system, providing foundation for agriculture water resource management.
Smooth structures on Eschenburg spaces: numerical computations
Butler, Leo T
2009-01-01
This paper numerically computes the topological and smooth invariants of Eschenburg spaces with small fourth cohomology group, following Kruggel's determination of the Kreck-Stolz invariants of Eschenburg spaces that satisfy condition C. The GNU GMP arbitrary-precision library is utilised.
Smooth rank one perturbations of selfadjoint operators
Hassi, Seppo; Snoo, H.S.V. de; Willemsma, A.D.I.
1998-01-01
Let A be a selfadjoint operator in a Hilbert space aleph with inner product [.,.]. The rank one perturbations of A have the form A+tau [.,omega]omega, tau epsilon R, for some element omega epsilon aleph. In this paper we consider smooth perturbations, i.e. we consider omega epsilon dom \\A\\(k/2) for
Autophagic regulation of smooth muscle cell biology
Salabei, Joshua K.; Hill, Bradford G.
2014-01-01
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 (patho)physiology. PMID:25544597
Optimal Point Placement for Mesh Smoothing
Amenta, Nina; Bern, Marshall; Eppstein, David
1998-01-01
We study the problem of moving a vertex in an unstructured mesh of triangular, quadrilateral, or tetrahedral elements to optimize the shapes of adjacent elements. We show that many such problems can be solved in linear time using generalized linear programming. We also give efficient algorithms for some mesh smoothing problems that do not fit into the generalized linear programming paradigm.
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.
Smoothing-norm preconditioning for GMRES
DEFF Research Database (Denmark)
Hansen, Per Christian; Jensen, Toke Koldborg
2004-01-01
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...
Autonomic Modification of Intestinal Smooth Muscle Contractility
Montgomery, Laura E. A.; Tansey, Etain A.; Johnson, Chris D.; Roe, Sean M.; Quinn, Joe G.
2016-01-01
Intestinal smooth muscle contracts rhythmically in the absence of nerve and hormonal stimulation because of the activity of pacemaker cells between and within the muscle layers. This means that the autonomic nervous system modifies rather than initiates intestinal contractions. The practical described here gives students an opportunity to observe…
Evaluating the smoothness of color transformations
Aristova, Anna; Wang, Zhaohui; Hardeberg, Jon Y.
2011-01-01
Multi-dimensional look up tables (LUTs) are widely employed for color transformations due to its high accuracy and general applicability. Using the LUT model generally involves the color measurement of a large number of samples. The precision and uncertainty of the color measurement will be mainly represented in the LUTs, and will affect the smoothness of the color transformation. This, in turn, strongly influences the quality of the reproduced color images. To achieve high quality color image reproduction, the color transformation is required to be relatively smooth. In this study, we have investigated the inherent characteristics of LUTs' transformation from color measurement and their effects on the quality of reproduced images. We propose an algorithm to evaluate the smoothness of 3D LUT based color transformations quantitatively, which is based on the analysis of 3D LUTs transformation from RGB to CIELAB and the second derivative of the differences between adjacent points in vertical and horizontal ramps of each LUT entry. The performance of the proposed algorithm was compared with a those proposed in two recent studies on smoothness, and a better performance is reached by the proposed method.
Elliot, S J; Zorn, B H; McLeod, D G; Moul, J W; Nyberg, L; Striker, L J; Striker, G E
2003-01-01
Benign prostatic hyperplasia (BPH) involves proliferation of smooth muscle cells and increased deposition of extracellular matrix (ECM). We recently found that pentosan polysulfate (PPS) has marked effects on growth and ECM of smooth muscle cells derived from vascular tissues. We examined smooth muscle cells cultured from human prostates and the effects of PPS on their growth and ECM production. Fragments of surgical prostatectomy specimens were diced, digested with collagenase (0.01%), and placed in culture medium supplemented with 20% fetal bovine serum. Outgrowths of elongated cells were characterized by light microscopic examination and immunohistochemical techniques by the presence of F-actin, alpha-smooth muscle actin, and myosin, which is a characteristic of smooth muscle cells. Two independent isolates were propagated, and growth curves and ECM production were assessed in the presence and absence of PPS (10 or 100 microg/ml). PPS decreased cell number beginning at day 1 and throughout the incubation period, up to 4 days. The amount of the ECM degradative enzymes, metallo-proteinases MMP-9 and MMP-2, was examined by zymography. PPS did not alter the amount of MMP-2 in the supernatants but MMP-9 was increased 234.4 +/- 17.23-fold over control cells. Tissue inhibitor of MMP (TIMPS), examined by reverse zymography, increased 200% over control. The amount of alpha I type (IV) and alpha I type (I) collagen released in the supernatant, measured by ELISA, significantly decreased in PPS-treated cultures. In conclusion, we found that the administration of PPS decreased proliferation as well as ECM production in prostate smooth muscle. Since smooth muscle proliferation and ECM are involved in the pathophysiology of BPH, PPS may have therapeutic potential.
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. PMID:27468462
Single Image Super-Resolution via L0 Image Smoothing
Zhang Liu; Qi Huang; Jian Li; Qi Wang
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...
Smoothing analysis of HLSII storage ring magnets
Wang, Wei; Tang, Zheng; Yao, Qiu-Yang
2016-01-01
In order to improve the quality and stability of synchrotron light, Hefei Light Source has a major upgrade. Higher accuracy is necessary for installation and alignment of the storage ring magnets. It is not necessarily essential that the magnets are positioned exactly. In fact, the aim is to adjust neighboring magnets with a high accuracy to one another; in other words, these neighboring magnets are positioned on a smoothing curve. The paper presents an attempt to develop a reliable smoothing method based on curve fitting of least squares and iteration according to the structure characteristics of HLSII. The method significantly reduces the adjusting amount and range of the storage ring magnets. It improves productivity by a factor of one times.
Smooth embeddings with Stein surface images
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 boundary orientations). Pseudoconcave complex structures on Milnor fibers are found. A byproduct of this construction is a simple polynomial expression for the signature of the (p,q,npq-1) Milnor fiber. Akbulut corks in complex surfaces can always be chosen to be pseudoconvex or pseudoconcave submanifods. The main theorem is expressed via Stein handlebodies (possibly infinite), which are defined holomorphically in all dimensions by extending Stein theory to manifolds with noncompact boundary.
Quantum state smoothing for classical mixtures
Tan, D; Mølmer, K; Murch, K W
2016-01-01
In quantum mechanics, wave functions and density matrices represent our knowledge about a quantum system and give probabilities for the outcomes of measurements. If the combined dynamics and measurements on a system lead to a density matrix $\\rho(t)$ with only diagonal elements in a given basis $\\{|n\\rangle\\}$, it may be treated as a classical mixture, i.e., a system which randomly occupies the basis states $|n\\rangle$ with probabilities $\\rho_{nn}(t)$. Fully equivalent to so-called smoothing in classical probability theory, subsequent probing of the occupation of the states $|n\\rangle$ improves our ability to retrodict what was the outcome of a projective state measurement at time $t$. Here, we show with experiments on a superconducting qubit that the smoothed probabilities do not, in the same way as the diagonal elements of $\\rho$, permit a classical mixture interpretation of the state of the system at the past time $t$.
Protostellar outflows with Smoothed Particle Magnetohydrodynamics (SPMHD)
Bürzle, Florian; Stasyszyn, Federico; Dolag, Klaus; Klessen, Ralf S
2011-01-01
The protostellar collapse of a molecular cloud core is usually accompanied by outflow phenomena. The latter are thought to be driven by magnetorotational processes from the central parts of the protostellar disc. While several 3D AMR/nested grid studies of outflow phenomena in collapsing magnetically supercritical dense cores have been reported in the literature, so far no such simulation has been performed using the Smoothed Particle Hydrodynamics (SPH) method. This is mainly due to intrinsic numerical difficulties in handling magnetohydrodynamics within SPH, which only recently were partly resolved. In this work, we use an approach where we evolve the magnetic field via the induction equation, augmented with stability correction and divergence cleaning schemes. We consider the collapse of a rotating core of one solar mass, threaded by a weak magnetic field initially parallel to the rotation axis so that the core is magnetically supercritical. We show, that Smoothed Particle Magnetohydrodynamics (SPMHD) is a...
Smooth homogeneous structures in operator theory
Beltita, Daniel
2005-01-01
Geometric ideas and techniques play an important role in operator theory and the theory of operator algebras. Smooth Homogeneous Structures in Operator Theory builds the background needed to understand this circle of ideas and reports on recent developments in this fruitful field of research. Requiring only a moderate familiarity with functional analysis and general topology, the author begins with an introduction to infinite dimensional Lie theory with emphasis on the relationship between Lie groups and Lie algebras. A detailed examination of smooth homogeneous spaces follows. This study is illustrated by familiar examples from operator theory and develops methods that allow endowing such spaces with structures of complex manifolds. The final section of the book explores equivariant monotone operators and Kähler structures. It examines certain symmetry properties of abstract reproducing kernels and arrives at a very general version of the construction of restricted Grassmann manifolds from the theory of loo...
Compensating for estimation smoothing in kriging
Olea, R.A.; Pawlowsky, Vera
1996-01-01
Smoothing is a characteristic inherent to all minimum mean-square-error spatial estimators such as kriging. Cross-validation can be used to detect and model such smoothing. Inversion of the model produces a new estimator-compensated kriging. A numerical comparison based on an exhaustive permeability sampling of a 4-fr2 slab of Berea Sandstone shows that the estimation surface generated by compensated kriging has properties intermediate between those generated by ordinary kriging and stochastic realizations resulting from simulated annealing and sequential Gaussian simulation. The frequency distribution is well reproduced by the compensated kriging surface, which also approximates the experimental semivariogram well - better than ordinary kriging, but not as well as stochastic realizations. Compensated kriging produces surfaces that are more accurate than stochastic realizations, but not as accurate as ordinary kriging. ?? 1996 International Association for Mathematical Geology.
SPHGR: Smoothed-Particle Hydrodynamics Galaxy Reduction
Thompson, Robert
2015-02-01
SPHGR (Smoothed-Particle Hydrodynamics Galaxy Reduction) is a python based open-source framework for analyzing smoothed-particle hydrodynamic simulations. Its basic form can run a baryonic group finder to identify galaxies and a halo finder to identify dark matter halos; it can also assign said galaxies to their respective halos, calculate halo & galaxy global properties, and iterate through previous time steps to identify the most-massive progenitors of each halo and galaxy. Data about each individual halo and galaxy is collated and easy to access. SPHGR supports a wide range of simulations types including N-body, full cosmological volumes, and zoom-in runs. Support for multiple SPH code outputs is provided by pyGadgetReader (ascl:1411.001), mainly Gadget (ascl:0003.001) and TIPSY (ascl:1111.015).
Relativistic point interactions: Approximation by smooth potentials
Hughes, Rhonda J.
1997-06-01
We show that the four-parameter family of one-dimensional relativistic point interactions studied by Benvegnu and Dąbrowski may be approximated in the strong resolvent sense by smooth, local, short-range perturbations of the Dirac Hamiltonian. In addition, we prove that the nonrelativistic limits correspond to the Schrödinger point interactions studied extensively by the author and Paul Chernoff.
Homotopy type of smooth weighted complete intersections
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
If the total degree d has no prime divisors less than(n+3)/2,then we prove that the homotopy type of complex odd dimensional smooth weighted complete intersection Xn(d;w) is determined by the dimension n,the total degree d,the Euler characteristic and the Kervaire invariant,provided that the weights w =(ω0,...,ωn+r) is pairwise relatively prime.
Ground state energy in smooth background fields
International Nuclear Information System (INIS)
We consider the backreaction problem for a smooth background field depending on one coordinate. We give a reformulation so that the scattering data of the corresponding Schroedinger equation become the independent variables. Using knowledge from the inverse scattering method it is shown that the problem can be reduced to an algebraic one within an arbitrary good approximation. For the simplest case an explicit example is given. (orig.)
Continuation model predictive control on smooth manifolds
Knyazev, Andrew; Malyshev, Alexander,
2015-01-01
Model predictive control (MPC) anticipates future events to take appropriate control actions. Nonlinear MPC (NMPC) describes systems with nonlinear models and/or constraints. Continuation MPC, suggested by T.~Ohtsuka in 2004, uses Krylov-Newton iterations. Continuation MPC is suitable for nonlinear problems and has been recently adopted for minimum time problems. We extend the continuation MPC approach to a case where the state is implicitly constrained to a smooth manifold. We propose an alg...
The Consumption Smoothing Benefits of Unemployment Insurance
Jonathan Gruber
1994-01-01
Previous research on unemployment insurance (UI) has focused on the costs of the program, in terms of the distorting effects of generous UI benefits on worker and firm behavior. For assessing the optimal size of an unemployment insurance program, however, it is also important to gauge the benefits of increased UI generosity, in terms of smoothing consumption across periods of joblessness. I do so through a reduced form approach which directly measures the effect of legislated variations in UI...
On Benzofuroindole Analogues as Smooth Muscle Relaxants
Ike dela Peña; Jae Hoon Cheong
2011-01-01
At least two laboratories have independently reported the synthesis of benzofuroindole compounds having potential therapeutic implications in many disease states including those that involve smooth muscle hyperactivity. Through a series of in vitro screenings, they demonstrated the efficacy (and selectivity) of these compounds to potentiate large conductance calcium- (Ca2+-) activated K+ (BKCa) channels, by far, the most characterized of all Ca2+-dependent K+ channels. Interestingly, promisin...
Smoothed Particle Magnetohydrodynamics (some shocking results...)
Price, D. J.; Monaghan, J. J.
2003-01-01
There have been some issues in the past in attempts to simulate magnetic fields using the Smoothed Particle Hydrodynamics (SPH) method. SPH is well suited to star formation problems because of its Lagrangian nature. We present new, stable and conservative methods for magnetohydrodynamics (MHD) in SPH and present numerical tests on both waves and shocks in one dimension to show that it gives robust and accurate results.
Demosaicing by Smoothing along 1D Features
Ajdin, Boris; Hullin, Matthias B.; Fuchs, Christian; Seidel, Hans-Peter; Lensch, Hendrik P. A.
2008-01-01
Most digital cameras capture color pictures in the form of an image mosaic, recording only one color channel at each pixel position. Therefore, an interpolation algorithm needs to be applied to reconstruct the missing color information. In this paper we present a novel Bayer pattern demosaicing approach, employing stochastic global optimization performed on a pixel neighborhood. We are minimizing a newly developed cost function that increases smoothness along one-dimen...
Gates, Henry Louis, Jr.
1994-01-01
Proposes that English studies is not a privileged route to addressing and redressing social ills. Questions whether literary studies is now or has ever been a "serious" enterprise or whether those who engage in it are overly self-serious. (HB)
On the thermodynamics of smooth muscle contraction
Stålhand, Jonas; McMeeking, Robert M.; Holzapfel, Gerhard A.
2016-09-01
Cell function is based on many dynamically complex networks of interacting biochemical reactions. Enzymes may increase the rate of only those reactions that are thermodynamically consistent. In this paper we specifically treat the contraction of smooth muscle cells from the continuum thermodynamics point of view by considering them as an open system where matter passes through the cell membrane. We systematically set up a well-known four-state kinetic model for the cross-bridge interaction of actin and myosin in smooth muscle, where the transition between each state is driven by forward and reverse reactions. Chemical, mechanical and energy balance laws are provided in local forms, while energy balance is also formulated in the more convenient temperature form. We derive the local (non-negative) production of entropy from which we deduce the reduced entropy inequality and the constitutive equations for the first Piola-Kirchhoff stress tensor, the heat flux, the ion and molecular flux and the entropy. One example for smooth muscle contraction is analyzed in more detail in order to provide orientation within the established general thermodynamic framework. In particular the stress evolution, heat generation, muscle shorting rate and a condition for muscle cooling are derived.
Coordinating with Humans by Adjustable-Autonomy for Multirobot Pursuit (CHAMP)
Dumond, Danielle; Ayers, Jeanine; Schurr, Nathan; Carlin, Alan; Burke, Dustin; Rousseau, Jeffrey
2012-06-01
One of the primary challenges facing the modern small-unit tactical team is the ability of the unit to safely and effectively search, explore, clear and hold urbanized terrain that includes buildings, streets, and subterranean dwellings. Buildings provide cover and concealment to an enemy and restrict the movement of forces while diminishing their ability to engage the adversary. The use of robots has significant potential to reduce the risk to tactical teams and dramatically force multiply the small unit's footprint. Despite advances in robotic mobility, sensing capabilities, and human-robot interaction, the use of robots in room clearing operations remains nascent. CHAMP is a software system in development that integrates with a team of robotic platforms to enable them to coordinate with a human operator performing a search and pursuit task. In this way, the human operator can either give control to the robots to search autonomously, or can retain control and direct the robots where needed. CHAMP's autonomy is built upon a combination of adversarial pursuit algorithms and dynamic function allocation strategies that maximize the team's resources. Multi-modal interaction with CHAMP is achieved using novel gesture-recognition based capabilities to reduce the need for heads-down tele-operation. The Champ Coordination Algorithm addresses dynamic and limited team sizes, generates a novel map of the area, and takes into account mission goals, user preferences and team roles. In this paper we show results from preliminary simulated experiments and find that the CHAMP system performs faster than traditional search and pursuit algorithms.
Existence of Hierarchies and Human's Pursuit of Top Hierarchy Lead to Power Law
Yu, Shuiyuan; Liu, Haitao
2016-01-01
The power law is ubiquitous in natural and social phenomena, and is considered as a universal relationship between the frequency and its rank for diverse social systems. However, a general model is still lacking to interpret why these seemingly unrelated systems share great similarity. Through a detailed analysis of natural language texts and simulation experiments based on the proposed 'Hierarchical Selection Model', we found that the existence of hierarchies and human's pursuit of top hierarchy lead to the power law. Further, the power law is a statistical and emergent performance of hierarchies, and it is the universality of hierarchies that contributes to the ubiquity of the power law.
The universal values of science and China’s Nobel Prize pursuit
Cao, Cong
2014-01-01
China does not seem to believe the existence of universally acknowledged values in science and fails to promote the observation of such values that also should be applied to every member of the scientific community and at all times. Or, there is a separation between the practice of science in China and the values represented by modern science. In this context, science, including the pursuit of the Nobel Prize, is more a pragmatic means to achieve the end of the political leadership – the nati...
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.
Recovery of Block-Sparse Representations from Noisy Observations via Orthogonal Matching Pursuit
Fang, Jun
2011-01-01
We study the problem of recovering the sparsity pattern of block-sparse signals from noise-corrupted measurements. A simple, efficient recovery method, namely, a block-version of the orthogonal matching pursuit (OMP) method, is considered in this paper and its behavior for recovering the block-sparsity pattern is analyzed. We provide sufficient conditions under which the block-version of the OMP can successfully recover the block-sparse representations in the presence of noise. Our analysis reveals that exploiting block-sparsity can improve the recovery ability and lead to a guaranteed recovery for a higher sparsity level. Numerical results are presented to corroborate our theoretical claim.
The Pursuit Behind the Escape——The Analysis of Harry Angstrom in Rabbit,Run
Institute of Scientific and Technical Information of China (English)
贾娜
2008-01-01
<正>The author John Updike illustrates the various contradictions between Middle-class American couples,the old and the young,the father and the son,the urban and the suburb,the rich and the poor,the soul and the body,peace and war,the God and the secular in his works.In 1960, Updike earned his fame through the publishing of Rabbit,Run and introduced one of his most unforgettable characters,the small town basketball star,Harry "Rabbit" Angstrom.This paper aims to explore Harry Angstrom’s pursuit behind his four "runs".
Research on Tool Wear Monitoring Method based on Project Pursuit Regression for a CNC Machine Tool
Directory of Open Access Journals (Sweden)
Qianjian Guo
2014-01-01
Full Text Available Tool wear is a major contributor to machining errors of a workpiece. Tool wear prediction is an effective way to estimate the wear loss in precision machining. In this study, all kinds of machining conditions are treated as the input variables, the wear loss of the tool is treated as the output variable, and Projection Pursuit Regression (PPR algorithm is proposed to mapping the tool wear loss. Finally, a real-time prediction device is presented based on the proposed PPR algorithm, and the prediction and measurement results are found to be in satisfied agreement with average error lower than 5%.
Airway hyperresponsiveness; smooth muscle as the principal actor.
Lauzon, Anne-Marie; Martin, James G
2016-01-01
Airway hyperresponsiveness (AHR) is a defining characteristic of asthma that refers to the capacity of the airways to undergo exaggerated narrowing in response to stimuli that do not result in comparable degrees of airway narrowing in healthy subjects. Airway smooth muscle (ASM) contraction mediates airway narrowing, but it remains uncertain as to whether the smooth muscle is intrinsically altered in asthmatic subjects or is responding abnormally as a result of the milieu in which it sits. ASM in the trachea or major bronchi does not differ in its contractile characteristics in asthmatics, but the more pertinent peripheral airways await complete exploration. The mass of ASM is increased in many but not all asthmatics and therefore cannot be a unifying hypothesis for AHR, although when increased in mass it may contribute to AHR. The inability of a deep breath to reverse or prevent bronchial narrowing in asthma may reflect an intrinsic difference in the mechanisms that lead to softening of contracted ASM when subjected to stretch. Cytokines such as interleukin-13 and tumor necrosis factor-α promote a more contractile ASM phenotype. The composition and increased stiffness of the matrix in which ASM is embedded promotes a more proliferative and pro-inflammatory ASM phenotype, but the expected dedifferentiation and loss of contractility have not been shown. Airway epithelium may drive ASM proliferation and/or molecular remodeling in ways that may lead to AHR. In conclusion, AHR is likely multifactorial in origin, reflecting the plasticity of ASM properties in the inflammatory environment of the asthmatic airway. PMID:26998246
Smoothing problems in nuclear and particle physics
International Nuclear Information System (INIS)
Complete text of publication follows. Mathematics is the universal language of all natural sciences, in particular, of theoretical physics. Thus, the same mathematical problem, e.g. the smoothing can appear in various fields, namely in Nuclear and Particle physics. A new type of smoothing of the nuclear level density was introduced in Ref. [1]. The weight function of the new smoothing function was also used in a new phenomenological nuclear potential the so called Salamon-Vertse (SV) potential, which becomes zero smoothly at finite distance. The use of the same weight function of the smoothing of the level density seems to be a good idea in particle physics too. At the heart of every quantum field theory there is the need for renormalization. This procedure is required to obtain measurable physical quantities. Renormalization is usually performed perturbatively, however, in some cases a non-perturbative treatment is a necessity which can be realized by e.g. the functional renormalization group (RG) method by using approximations. The approximated RG flow depends on the choice of the so called regulator function, i.e. on the renormalization scheme and physical results could become scheme-dependent. Therefore, a general issue is the comparison of results obtained by various RG schemes (i.e. various types of regulator functions). In order to optimize the scheme dependence an optimization procedure has already been worked out and in the leading order of the derivative expansion, an explicit form for the optimized regulator was provided, ropt(y) = a (1/yb - 1) θ(1 - y) (4) where θ(y) is the Heaviside step function. It was also shown that this simple form of the optimized regulator does not support a derivative expansion beyond second order because it is a function of class C0 with compact support thus it is a continuous function and it has a finite range but it is not differentiable. It was argued the general criterion for optimization has to meet the necessary
Institute of Scientific and Technical Information of China (English)
WEN Shao-jun; ZHAO Li-min; WANG Shen-guo; LI Jing-xing; CHEN Hua-ying; LIU Jie-lin; LIU Ya; LUO Yi; Roo Changizi
2007-01-01
Background Current prosthetic, small diameter vascular grafts showing poor long term patency rates have led to the pursuit of other biological materials. Biomaterials that successfully integrate into surrounding tissue should match not only the mechanical properties of tissues, but also topography. Polyglycolic acid (70/30) has been used as synthetic grafts to determine whether human vascular smooth muscle cells and endothelial cells attach, survive and secrete endothelin and 6-keto-prostaglandin F1α (6-keto-PGF1α).Methods Endothelial cells and smooth muscle cells were isolated from adult human great saphenous vein. They were seeded on polyglycolic acid scaffold in vitro separately to grow vascular patch (Groups A and B respectively) and cocultured in vitro to grow into vascular patch (Group C). Smooth muscle cells and endothelial cells were identified by immunohistochemical analysis and growth of cells on polyglycolic acid was investigated using scanning electron microscopy. The levels of endothelin and 6-keto-PGF1α in the culturing solutions were examined by radioimmunology to measure endothelial function.Results Seed smooth muscle cells adhered to polyglycolic acid scaffold and over 28 days grew in the interstices to form a uniform cell distribution throughout the scaffold. Then seed endothelial cells formed a complete endothelial layer on the smooth muscle cells. The levels of endothelin and 6-keto-prostaglandin F1 alpha in the culturing solution were (234±29) pg/ml and (428+98) pg/ml respectively in Group C and (196+30) pg/ml and (346±120) pg/ml in Group B; both significantly higher than in Groups A and D (blank control group, all P＜0.05 ).Conclusions Cells could be grown successfully on polyglycolic acid and retain functions of secretion. Our next step is to use human saphenous vein smooth muscle cells and endothelial cells to grow tubular vascular grafts in vitro.
Transforming Growth Factor-β Induces Airway Smooth Muscle Hypertrophy
Goldsmith, Adam M.; Bentley, J. Kelley; Zhou, Limei; Jia, Yue; Bitar, Khalil N; Fingar, Diane C.; Hershenson, Marc B.
2005-01-01
Although smooth muscle hypertrophy is present in asthmatic airways, little is known about the biochemical pathways regulating airway smooth muscle protein synthesis, cell size, or accumulation of contractile apparatus proteins. We sought to develop a model of airway smooth muscle hypertrophy in primary cells using a physiologically relevant stimulus. We hypothesized that transforming growth factor (TGF)-β induces hypertrophy in primary bronchial smooth muscle cells. Primary human bronchial sm...
Airway Smooth Muscle Growth in Asthma: Proliferation, Hypertrophy, and Migration
Bentley, J. Kelley; Hershenson, Marc B.
2008-01-01
Increased airway smooth muscle mass is present in fatal and non-fatal asthma. However, little information is available regarding the cellular mechanism (i.e., hyperplasia vs. hypertrophy). Even less information exists regarding the functional consequences of airway smooth muscle remodeling. It would appear that increased airway smooth muscle mass would tend to increase airway narrowing and airflow obstruction. However, the precise effects of increased airway smooth muscle mass on airway narro...
MortalitySmooth: An R Package for Smoothing Poisson Counts with P-Splines
Directory of Open Access Journals (Sweden)
Carlo G. Camarda
2012-07-01
Full Text Available The MortalitySmooth package provides a framework for smoothing count data in both one- and two-dimensional settings. Although general in its purposes, the package is specifically tailored to demographers, actuaries, epidemiologists, and geneticists who may be interested in using a practical tool for smoothing mortality data over ages and/or years. The total number of deaths over a specified age- and year-interval is assumed to be Poisson-distributed, and P-splines and generalized linear array models are employed as a suitable regression methodology. Extra-Poisson variation can also be accommodated.Structured in an S3 object orientation system, MortalitySmooth has two main functions which t the data and dene two classes of objects:Mort1Dsmooth and Mort2Dsmooth. The methods for these classes (print, summary, plot, predict, and residuals are also included. These features make it easy for users to extract and manipulate the outputs.In addition, a collection of mortality data is provided. This paper provides an overview of the design, aims, and principles of MortalitySmooth, as well as strategies for applying it and extending its use.
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...
Exponential smoothing for financial time series data forecasting
Directory of Open Access Journals (Sweden)
Kuzhda, Tetyana Ivanivna
2014-05-01
Full Text Available The article begins with the formulation for predictive learning called exponential smoothing forecasting. The exponential smoothing is commonly applied to financial markets such as stock or bond, foreign exchange, insurance, credit, primary and secondary markets. The exponential smoothing models are useful in providing the valuable decision information for investors. Simple and double exponential smoothing models are two basic types of exponential smoothing method. The simple exponential smoothing method is suitable for financial time series forecasting for the specified time period. The simple exponential smoothing weights past observations with exponentially decreasing weights to forecast future values. The double exponential smoothing is a refinement of the simple exponential smoothing model but adds another component which takes into account any trend in the data. The double exponential smoothing is designed to address this type of data series by taking into account any trend in the data. Measurement of the forecast accuracy is described in this article. Finally, the quantitative value of the price per common share forecast using simple exponential smoothing is calculated. The applied recommendations concerning determination of the price per common share forecast using double exponential smoothing are shown in the article.
NEWTON METHOD FOR SOLVING A CLASS OF SMOOTH CONVEX PROGRAMMING
Institute of Scientific and Technical Information of China (English)
YAO Yi-rong; ZHANG Lian-sheng; HAN Bo-shun
2005-01-01
An algorithm for solving a class of smooth convex programming is given. Using smooth exact multiplier penalty function,a smooth convex programming is minimized to a minimizing strongly convex function on the compact set was reduced. Then the strongly convex function with a Newton method on the given compact set was minimized.
Alternative Smoothing and Scaling Strategies for Weighted Composite Scores
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…
Directory of Open Access Journals (Sweden)
Sara Casella
2015-10-01
Full Text Available Type 2 diabetes mellitus (T2DM is a disease reaching a pandemic proportion in developed countries and a major risk factor for almost all cardiovascular diseases and their adverse clinical manifestations. T2DM leads to several macrovascular and microvascular alterations that influence the progression of cardiovascular diseases. Vascular smooth muscle cells (VSMCs are fundamental players in macrovascular alterations of T2DM patients. VSMCs display phenotypic and functional alterations that reflect an altered intracellular biomolecular scenario of great vessels of T2DM patients. Hyperglycemia itself and through intraparietal accumulation of advanced glycation-end products (AGEs activate different pathways, in particular nuclear factor-κB and MAPKs, while insulin and insulin growth-factor receptors (IGFR are implicated in the activation of Akt and extracellular-signal-regulated kinases (ERK 1/2. Nuclear factor-κB is also responsible of increased susceptibility of VSMCs to pro-apoptotic stimuli. Down-regulation of insulin growth-factor 1 receptors (IGFR-1R activity in diabetic vessels also influences negatively miR-133a levels, so increasing apoptotic susceptibility of VSMCs. Alterations of those bimolecular pathways and related genes associate to the prevalence of a synthetic phenotype of VSMCs induces extracellular matrix alterations of great vessels. A better knowledge of those biomolecular pathways and related genes in VSMCs will help to understand the mechanisms leading to macrovascular alterations in T2DM patients and to suggest new targeted therapies.
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.
IN PURSUIT OF EXCELLENCE: A STUDENT GUIDE TO ELITE SPORTS DEVELOPMENT
Directory of Open Access Journals (Sweden)
Michael Hill
2007-09-01
Full Text Available DESCRIPTION This book is about how it is possible to achieve the excellence in sport in modern times. PURPOSE To cover the past of competitive sport of today as well as discussing current issues in sport such as drugs. The comparison of elite sporting methods in leading sport countries is also included. AUDIENCE Students in the field and anybody interested in modern sports especially in the history of it. FEATURES A comprehensive introduction about the pursuit of excellence in sport, covering the key issues such as the history and tradition of sporting excellence; comparisons of elite high-performance sport programmes in Australia, the USA, East Germany and France; the historical, social, political and economic impacts of sporting excellence in the UK; current issues and debates, including drugs in sport; and the future for high-performance sport. ASSESSMENT Having a clear framework for understanding and exploring key issues, questions for discussion, websites and suggestions for further reading, "In Pursuit of Excellence" is a helpful source for students and for any person interested in sport and sport-relevant issues
Culture shapes whether the pursuit of happiness predicts higher or lower well-being.
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.
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.
Projection pursuit cluster model and its application in water quality assessment
Institute of Scientific and Technical Information of China (English)
WANG Shun-jiu; YANG Zhi-feng; DING Jing
2004-01-01
One of the difficulties frequently encountered in water quality assessment is that there are many factors and they cannot be assessed according to one factor, all the effect factors associated with water quality must be used. In order to overcome this issues the projection pursuit principle is introduced into water quality assessment, and projection pursuit cluster(PPC) model is developed in this study. The PPC model makes the transition from high dimension to one-dimension. In other words, based on the PPC model, multifactor problem can be converted to one factor problem. The application of PPC model can be divided into four parts: (1) to estimate projection index function ; (2) to find the right projection direction; (3) to calculate projection characteristic value of the sample , and (4) to draw comprehensive analysis on the basis of . On the other hand, the empirical formula of cutoff radius is developed, which is benefit for the model to be used in practice. Finally, a case study of water quality assessment is proposed in this paper. The results showed that the PPC model is reasonable, and it is more objective and less subjective in water quality assessment. It is a new method for multivariate problem comprehensive analysis.
Impaired motor memory for a pursuit rotor task following Stage 2 sleep loss in college students.
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. PMID:10607127
Abrams, Joshua; Einhorn, Zev; Seiler, Christoph; Zong, Alan B; Sweeney, H Lee; Pack, Michael
2016-05-01
Smooth muscle contraction is controlled by the regulated activity of the myosin heavy chain ATPase (Myh11). Myh11 mutations have diverse effects in the cardiovascular, digestive and genitourinary systems in humans and animal models. We previously reported a recessive missense mutation, meltdown (mlt), which converts a highly conserved tryptophan to arginine (W512R) in the rigid relay loop of zebrafish Myh11. The mlt mutation disrupts myosin regulation and non-autonomously induces invasive expansion of the intestinal epithelium. Here, we report two newly identified missense mutations in the switch-1 (S237Y) and coil-coiled (L1287M) domains of Myh11 that fail to complement mlt Cell invasion was not detected in either homozygous mutant but could be induced by oxidative stress and activation of oncogenic signaling pathways. The smooth muscle defect imparted by the mlt and S237Y mutations also delayed intestinal transit, and altered vascular function, as measured by blood flow in the dorsal aorta. The cell-invasion phenotype induced by the three myh11 mutants correlated with the degree of myosin deregulation. These findings suggest that the vertebrate intestinal epithelium is tuned to the physical state of the surrounding stroma, which, in turn, governs its response to physiologic and pathologic stimuli. Genetic variants that alter the regulation of smooth muscle myosin might be risk factors for diseases affecting the intestine, vasculature, and other tissues that contain smooth muscle or contractile cells that express smooth muscle proteins, particularly in the setting of redox stress. PMID:26893369
Directory of Open Access Journals (Sweden)
Ahmad Nazim Aimran
2014-09-01
Full Text Available This research develops techniques which are helpful in forecasting univariate time series data. The techniques used in this study are Single Exponential Smoothing (SES, Double Exponential Smoothing (DES, Holt’s (Brown and Adaptive Response Rate Exponential Smoothing (ARRES Techniques. For the purpose of this study, secondary data of Malaysia Population covering the period 1957 up to 2013 was obtained from the Department of Statistics Malaysia. From the result obtained, Holt’s method was found to be the best method to forecast the Malaysia population since it produces the lowest Mean Square Error (MSE value which is 38,273.3 compared to 210,480.29 for SES, 38,827.7 for DEB and 209,835.8 for ARRES techniques. Keywords: Univariate, Forecasting, Single Exponential Smoothing, Double Exponential Smoothing, And Adaptive Response Rate Exponential Smoothing, Holt’s (Brown.
Quijano, J C; Raynaud, F; Nguyen, D; Piacentini, N; Meister, J J
2016-01-01
Vascular smooth muscle cells exhibit intercellular Ca(2+) waves in response to local mechanical or KCl stimulation. Recently, a new type of intercellular Ca(2+) wave was observed in vitro in a linear arrangement of smooth muscle cells. The intercellular wave was denominated ultrafast Ca(2+) wave and it was suggested to be the result of the interplay between membrane potential and Ca(2+) dynamics which depended on influx of extracellular Ca(2+), cell membrane depolarization and its intercel- lular propagation. In the present study we measured experimentally the conduction velocity of the membrane depolarization and performed simulations of the ultrafast Ca(2+) wave along coupled smooth muscle cells. Numerical results reproduced a wide spectrum of experimental observations, including Ca(2+) wave velocity, electrotonic membrane depolarization along the network, effects of inhibitors and independence of the Ca(2+) wave speed on the intracellular stores. The numerical data also provided new physiological insights suggesting ranges of crucial model parameters that may be altered experimentally and that could significantly affect wave kinetics allowing the modulation of the wave characteristics experimentally. Numerical and experimental results supported the hypothesis that the propagation of membrane depolarization acts as an intercellular messenger mediating intercellular ultrafast Ca(2+) waves in smooth muscle cells. PMID:27507785
Intercellular ultrafast Ca2+ wave in vascular smooth muscle cells: numerical and experimental study
Quijano, J. C.; Raynaud, F.; Nguyen, D.; Piacentini, N.; Meister, J. J.
2016-01-01
Vascular smooth muscle cells exhibit intercellular Ca2+ waves in response to local mechanical or KCl stimulation. Recently, a new type of intercellular Ca2+ wave was observed in vitro in a linear arrangement of smooth muscle cells. The intercellular wave was denominated ultrafast Ca2+ wave and it was suggested to be the result of the interplay between membrane potential and Ca2+ dynamics which depended on influx of extracellular Ca2+, cell membrane depolarization and its intercel- lular propagation. In the present study we measured experimentally the conduction velocity of the membrane depolarization and performed simulations of the ultrafast Ca2+ wave along coupled smooth muscle cells. Numerical results reproduced a wide spectrum of experimental observations, including Ca2+ wave velocity, electrotonic membrane depolarization along the network, effects of inhibitors and independence of the Ca2+ wave speed on the intracellular stores. The numerical data also provided new physiological insights suggesting ranges of crucial model parameters that may be altered experimentally and that could significantly affect wave kinetics allowing the modulation of the wave characteristics experimentally. Numerical and experimental results supported the hypothesis that the propagation of membrane depolarization acts as an intercellular messenger mediating intercellular ultrafast Ca2+ waves in smooth muscle cells. PMID:27507785
Smooth Nanowire/Polymer Composite Transparent Electrodes
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.
Compressive Sensing via Nonlocal Smoothed Rank Function.
Fan, Ya-Ru; Huang, Ting-Zhu; Liu, Jun; Zhao, Xi-Le
2016-01-01
Compressive sensing (CS) theory asserts that we can reconstruct signals and images with only a small number of samples or measurements. Recent works exploiting the nonlocal similarity have led to better results in various CS studies. To better exploit the nonlocal similarity, in this paper, we propose a non-convex smoothed rank function based model for CS image reconstruction. We also propose an efficient alternating minimization method to solve the proposed model, which reduces a difficult and coupled problem to two tractable subproblems. Experimental results have shown that the proposed method performs better than several existing state-of-the-art CS methods for image reconstruction.
Compressive Sensing via Nonlocal Smoothed Rank Function
Fan, Ya-Ru; Liu, Jun; Zhao, Xi-Le
2016-01-01
Compressive sensing (CS) theory asserts that we can reconstruct signals and images with only a small number of samples or measurements. Recent works exploiting the nonlocal similarity have led to better results in various CS studies. To better exploit the nonlocal similarity, in this paper, we propose a non-convex smoothed rank function based model for CS image reconstruction. We also propose an efficient alternating minimization method to solve the proposed model, which reduces a difficult and coupled problem to two tractable subproblems. Experimental results have shown that the proposed method performs better than several existing state-of-the-art CS methods for image reconstruction. PMID:27583683
Method for producing smooth inner surfaces
Energy Technology Data Exchange (ETDEWEB)
Cooper, Charles A.
2016-05-17
The invention provides a method for preparing superconducting cavities, the method comprising causing polishing media to tumble by centrifugal barrel polishing within the cavities for a time sufficient to attain a surface smoothness of less than 15 nm root mean square roughness over approximately a 1 mm.sup.2 scan area. The method also provides for a method for preparing superconducting cavities, the method comprising causing polishing media bound to a carrier to tumble within the cavities. The method also provides for a method for preparing superconducting cavities, the method comprising causing polishing media in a slurry to tumble within the cavities.
Impact modeling with Smooth Particle Hydrodynamics
Energy Technology Data Exchange (ETDEWEB)
Stellingwerf, R.F.; Wingate, C.A.
1993-07-01
Smooth Particle Hydrodynamics (SPH) can be used to model hypervelocity impact phenomena via the addition of a strength of materials treatment. SPH is the only technique that can model such problems efficiently due to the combination of 3-dimensional geometry, large translations of material, large deformations, and large void fractions for most problems of interest. This makes SPH an ideal candidate for modeling of asteroid impact, spacecraft shield modeling, and planetary accretion. In this paper we describe the derivation of the strength equations in SPH, show several basic code tests, and present several impact test cases with experimental comparisons.
Contruction of a smoothed DEA frontier
João Carlos Correia Baptista Soares de Mello; Marcos Pereira Estellita Lins; Eliane Gonçalves Gomes
2002-01-01
It is known that the DEA multipliers model does not allow a unique solution for the weights. This is due to the absence of unique derivatives in the extreme-efficient points, which is a consequence of the piecewise linear nature of the frontier. In this paper we propose a method to solve this problem, consisting of changing the original DEA frontier for a new one, smooth (with continuous derivatives at every point) and closest to the original frontier. We present the theoretical development f...
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.
A new smoothing scheme for mathematical programs with complementarity constraints
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper, we consider a mathematical program with complementarity constraints (MPCC). We present a new smoothing scheme for this problem, which makes the primal structure of the complementarity part unchanged mostly. For the new smoothing problem, we show that the linear independence constraint qualification (LICQ) holds under some conditions. We also analyze the convergence behavior of the smoothing problem, and get some sufficient conditions such that an accumulation point of stationary points of the smoothing problems is C (M, B)-stationarity respectively. Based on the smoothing problem, we establish an algorithm to solve the primal MPCC problem. Some numerical experiments are given in the paper.
Energy Technology Data Exchange (ETDEWEB)
Reutter, B.W.; Algazi, V.R.; Huesman, R.H.
2000-10-11
Nonlinear edge preserving smoothing often is performed prior to medical image segmentation. The goal of the nonlinear smoothing is to improve the accuracy of the segmentation by preserving changes in image intensity at the boundaries of structures of interest, while smoothing random variations due to noise in the interiors of the structures. Methods include median filtering and morphology operations such as gray scale erosion and dilation, as well as spatially varying smoothing driven by local contrast measures. Rather than irreversibly altering the image data prior to segmentation, the approach described here has the potential to unify nonlinear edge preserving smoothing with segmentation based on differential edge detection at multiple scales. The analysis of n-D image data is decomposed into independent 1-D problems that can be solved quickly. Smoothing in various directions along 1-D profiles through the n-D data is driven by a measure of local structure separation, rather than by a local contrast measure. Isolated edges are preserved independent of their contrast, given an adequate contrast to noise ratio.
Smooth Tubercle Bacilli: Neglected Opportunistic Tropical Pathogens
Directory of Open Access Journals (Sweden)
Djaltou eAboubaker
2016-01-01
Full Text Available Smooth tubercle bacilli (STB including ‘‘Mycobacterium canettii’’ are members of the Mycobacterium tuberculosis complex (MTBC which cause non-contagious tuberculosis in human. This group comprises less than one hundred isolates characterized by smooth colonies and cordless organisms. Most STB isolates have been obtained from patients exposed to the Republic of Djibouti but seven isolates, including the three seminal ones obtained by Georges Canetti between 1968 and 1970, were recovered from patients in France, Madagascar, Sub-Sahara East Africa and French Polynesia. STB form a genetically heterogeneous group of MTBC organisms with large 4.48 ± 0.05 Mb genomes which may link Mycobacterium kansasii to MTBC organisms. Lack of inter-human transmission suggested a yet unknown environmental reservoir. Clinical data indicate a respiratory tract route of contamination and the digestive tract as an alternative route of contamination. Further epidemiological and clinical studies are warranted to elucidate areas of uncertainty regarding these unusual mycobacteria and the tuberculosis they cause.
Cortex phellodendri Extract Relaxes Airway Smooth Muscle.
Jiang, Qiu-Ju; Chen, Weiwei; Dan, Hong; Tan, Li; Zhu, He; Yang, Guangzhong; Shen, Jinhua; Peng, Yong-Bo; Zhao, Ping; Xue, Lu; Yu, Meng-Fei; Ma, Liqun; Si, Xiao-Tang; Wang, Zhuo; Dai, Jiapei; Qin, Gangjian; Zou, Chunbin; Liu, Qing-Hua
2016-01-01
Cortex phellodendri is used to reduce fever and remove dampness and toxin. Berberine is an active ingredient of C. phellodendri. Berberine from Argemone ochroleuca can relax airway smooth muscle (ASM); however, whether the nonberberine component of C. phellodendri has similar relaxant action was unclear. An n-butyl alcohol extract of C. phellodendri (NBAECP, nonberberine component) was prepared, which completely inhibits high K(+)- and acetylcholine- (ACH-) induced precontraction of airway smooth muscle in tracheal rings and lung slices from control and asthmatic mice, respectively. The contraction induced by high K(+) was also blocked by nifedipine, a selective blocker of L-type Ca(2+) channels. The ACH-induced contraction was partially inhibited by nifedipine and pyrazole 3, an inhibitor of TRPC3 and STIM/Orai channels. Taken together, our data demonstrate that NBAECP can relax ASM by inhibiting L-type Ca(2+) channels and TRPC3 and/or STIM/Orai channels, suggesting that NBAECP could be developed to a new drug for relieving bronchospasm. PMID:27239213
Cortex phellodendri Extract Relaxes Airway Smooth Muscle
Directory of Open Access Journals (Sweden)
Qiu-Ju Jiang
2016-01-01
Full Text Available Cortex phellodendri is used to reduce fever and remove dampness and toxin. Berberine is an active ingredient of C. phellodendri. Berberine from Argemone ochroleuca can relax airway smooth muscle (ASM; however, whether the nonberberine component of C. phellodendri has similar relaxant action was unclear. An n-butyl alcohol extract of C. phellodendri (NBAECP, nonberberine component was prepared, which completely inhibits high K+- and acetylcholine- (ACH- induced precontraction of airway smooth muscle in tracheal rings and lung slices from control and asthmatic mice, respectively. The contraction induced by high K+ was also blocked by nifedipine, a selective blocker of L-type Ca2+ channels. The ACH-induced contraction was partially inhibited by nifedipine and pyrazole 3, an inhibitor of TRPC3 and STIM/Orai channels. Taken together, our data demonstrate that NBAECP can relax ASM by inhibiting L-type Ca2+ channels and TRPC3 and/or STIM/Orai channels, suggesting that NBAECP could be developed to a new drug for relieving bronchospasm.
Analytic functions smooth up to the boundary
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...
On Benzofuroindole Analogues as Smooth Muscle Relaxants
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Ike dela Peña
2011-01-01
Full Text Available At least two laboratories have independently reported the synthesis of benzofuroindole compounds having potential therapeutic implications in many disease states including those that involve smooth muscle hyperactivity. Through a series of in vitro screenings, they demonstrated the efficacy (and selectivity of these compounds to potentiate large conductance calcium- (Ca2+- activated K+ (BKCa channels, by far, the most characterized of all Ca2+-dependent K+ channels. Interestingly, promising benzofuroindole derivatives such as compound 7 (10H-benzo[4,5]furo[3,2-b]indole and compound 22 (4-chloro-7-trifluoromethyl-10H-benzo[4,5]furo[3,2-b]indole-1-carboxylic acid both exhibited high bladder (versus aorta selectivity, making them attractive alternative treatments for bladder overactivity. In recent reports, compound 22 (LDD175 or TBIC also showed inhibition of ileum and uterine contractions, indicating multiple target tissues, which is not surprising as BKCa channels are ubiquitously expressed in the animal and human tissues. In this paper, the authors discuss the value of benzofuroindole compounds and the challenges that need to be overcome if they were considered as smooth muscle relaxants.
Isotropic Growth of Graphene toward Smoothing Stitching.
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. PMID:27403842
Isotropic Growth of Graphene toward Smoothing Stitching.
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.
Directory of Open Access Journals (Sweden)
Rajeev D S Raizada
Full Text Available Spatial smoothness is helpful when averaging fMRI signals across multiple subjects, as it allows different subjects' corresponding brain areas to be pooled together even if they are slightly misaligned. However, smoothing is usually not applied when performing multivoxel pattern-based analyses (MVPA, as it runs the risk of blurring away the information that fine-grained spatial patterns contain. It would therefore be desirable, if possible, to carry out pattern-based analyses which take unsmoothed data as their input but which produce smooth images as output. We show here that the Gaussian Naive Bayes (GNB classifier does precisely this, when it is used in "searchlight" pattern-based analyses. We explain why this occurs, and illustrate the effect in real fMRI data. Moreover, we show that analyses using GNBs produce results at the multi-subject level which are statistically robust, neurally plausible, and which replicate across two independent data sets. By contrast, SVM classifiers applied to the same data do not generate a replication, even if the SVM-derived searchlight maps have smoothing applied to them. An additional advantage of GNB classifiers for searchlight analyses is that they are orders of magnitude faster to compute than more complex alternatives such as SVMs. Collectively, these results suggest that Gaussian Naive Bayes classifiers may be a highly non-naive choice for multi-subject pattern-based fMRI studies.
Strain history and TGF-β1 induce urinary bladder wall smooth muscle remodeling and elastogenesis.
Heise, Rebecca L; Parekh, Aron; Joyce, Erinn M; Chancellor, Michael B; Sacks, Michael S
2012-01-01
Mechanical cues that trigger pathological remodeling in smooth muscle tissues remain largely unknown and are thought to be pivotal triggers for strain-induced remodeling. Thus, an understanding of the effects mechanical stimulation is important to elucidate underlying mechanisms of disease states and in the development of methods for smooth muscle tissue regeneration. For example, the urinary bladder wall (UBW) adaptation to spinal cord injury (SCI) includes extensive hypertrophy as well as increased collagen and elastin, all of which profoundly alter its mechanical response. In addition, the pro-fibrotic growth factor TGF-β1 is upregulated in pathologies of other smooth muscle tissues and may contribute to pathological remodeling outcomes. In the present study, we utilized an ex vivo organ culture system to investigate the response of UBW tissue under various strain-based mechanical stimuli and exogenous TGF-β1 to assess extracellular matrix (ECM) synthesis, mechanical responses, and bladder smooth muscle cell (BSMC) phenotype. Results indicated that a 0.5-Hz strain frequency triangular waveform stimulation at 15% strain resulted in fibrillar elastin production, collagen turnover, and a more compliant ECM. Further, this stretch regime induced changes in cell phenotype while the addition of TGF-β1 altered this phenotype. This phenotypic shift was further confirmed by passive strip biomechanical testing, whereby the bladder groups treated with TGF-β1 were more compliant than all other groups. TGF-β1 increased soluble collagen production in the cultured bladders. Overall, the 0.5-Hz strain-induced remodeling caused increased compliance due to elastogenesis, similar to that seen in early SCI bladders. Thus, organ culture of bladder strips can be used as an experimental model to examine ECM remodeling and cellular phenotypic shift and potentially elucidate BMSCs ability to produce fibrillar elastin using mechanical stretch either alone or in combination with
Structure Analysis of Network Traffic Matrix Based on Relaxed Principal Component Pursuit
Wang, Zhe; Xu, Ke; Yin, Baolin
2011-01-01
The network traffic matrix is a kind of flow-level Internet traffic data and is widely applied to network operation and management. It is a crucial problem to analyze the composition and structure of traffic matrix; some mathematical approaches such as Principal Component Analysis (PCA) were used to handle that problem. In this paper, we first argue that PCA performs poorly for analyzing traffic matrixes polluted by large volume anomalies, then propose a new composition model of the network traffic matrix. According to our model, structure analysis can be formally defined as decomposing a traffic matrix into low-rank, sparse, and noise sub-matrixes, which is equal to the Robust Principal Component Analysis (RPCA) problem defined in [13]. Based on the Relaxed Principal Component Pursuit (Relaxed PCP) method and the Accelerated Proximal Gradient (APG) algorithm, an iterative algorithm for decomposing a traffic matrix is presented, and our experiment results demonstrate its efficiency and flexibility. At last, f...
Consensus pursuit of heterogeneous multi-agent systems under a directed acyclic graph
Institute of Scientific and Technical Information of China (English)
Yan Jing; Guan Xin-Ping; Luo Xiao-Yuan
2011-01-01
This paper is concerned with the cooperative target pursuit problem by multiple agents based on directed acyclic graph. The target appears at a random location and moves only when sensed by the agents, and agents will pursue the target once they detect its existence. Since the ability of each agent may be different, we consider the heterogeneous multi-agent systems.According to the topology of the multi-agent systems, a novel consensus-based control law is proposed, where the target and agents are modeled as a leader and followers, respectively. Based on Mason's rule and signal flow graph analysis, the convergence conditions are provided to show that the agents can catch the target in a finite time. Finally, simulation studies are provided to verify the effectiveness of the proposed approach.
Head Pursuit Variable Structure Guidance Law for Three-dimensional Space Interception
Institute of Scientific and Technical Information of China (English)
Ge Lianzheng; Shen Yi; Gao Yunfeng; Zhao Lijun
2008-01-01
This article aims to develop a head pursuit (HP) guidance law for three-dimensional hypervelocity interception,so that the effect of the perturbation induced by seeker detection can be reduced.On the basis of a novel I-IP three-dimensional guidance model,a nonlinear variable structure guidance law is presented by using Lyapunov stability theory.The guidance law positions the interceptor ahead of the target on its flight trajectory,and the speed of the interceptor is required to be lower than that of the target.A numerical example of maneuvering ballistic target interception verifies the rightness of the guidance model and the effectiveness of the proposed method.
Simultaneous Greedy Analysis Pursuit for compressive sensing of multi-channel ECG signals.
Avonds, Yurrit; Liu, Yipeng; Van Huffel, Sabine
2014-01-01
This paper addresses compressive sensing for multi-channel ECG. Compared to the traditional sparse signal recovery approach which decomposes the signal into the product of a dictionary and a sparse vector, the recently developed cosparse approach exploits sparsity of the product of an analysis matrix and the original signal. We apply the cosparse Greedy Analysis Pursuit (GAP) algorithm for compressive sensing of ECG signals. Moreover, to reduce processing time, classical signal-channel GAP is generalized to the multi-channel GAP algorithm, which simultaneously reconstructs multiple signals with similar support. Numerical experiments show that the proposed method outperforms the classical sparse multi-channel greedy algorithms in terms of accuracy and the single-channel cosparse approach in terms of processing speed.
Kling, Johanna; Rodgers, Rachel F; Frisén, Ann
2016-03-01
Appearance investment has been proposed as a risk factor for the development of body dissatisfaction. Despite this, few studies have explored men's investment in their appearance. The aim of the present study was therefore to examine appearance investment as a prospective predictor of young men's endorsement and pursuit of appearance ideals. A community sample of 187 young men participated in a study at ages 21 and 24. Hierarchical multiple regressions revealed that appearance investment, as hypothesized, was a prospective predictor of increases in leanness orientation, media-ideal internalization, and muscularity behaviors. However, appearance investment did not predict increases in muscularity dissatisfaction. The present findings highlight the importance of including appearance investment in sociocultural models of the development of men's body image, and suggest that appearance investment may be an important target variable to consider when designing body dissatisfaction prevention and intervention programs tailored to young men. PMID:26523688
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.
The pursuit of happiness measurement: a psychometric model based on psychophysiological correlates.
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.
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.
The pursuit of excellence is not optional in the voluntary sector, it is essential.
Dunn, B; Mathews, S
2001-01-01
This paper outlines the continuous improvement journey of a voluntary organisation. The significant level of organisational growth and improving quality of services described is clearly linked to the organisation's commitment to improvement. One of the approaches used in adopting a total quality culture was the EFQM model, specifically interpreted for the voluntary sector. Until recently such an approach would have been considered alien to the sector, not least because of its origins in the business community. This article contradicts this assumption. Issues addressed include how the improvement process is driven, the use of performance measurement, external verification and the difficulties in accessing sector appropriate benchmark data. It is suggested that the pursuit of excellence is no longer optional for the voluntary sector, it is essential.
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. PMID:19881426
Money and the Pursuit of Happiness: In Good Times and Bad
Directory of Open Access Journals (Sweden)
Erika Rasure
2012-01-01
Full Text Available Money and the Pursuit of Happiness: In Good Times and Bad is a consumer’s introductory guide of personal reflection with money. The book’s author discusses how to develop a foundational relationship with one’s financial self in an effort to establish ongoing happiness and life satisfaction. The book can be an effective resource recommended by financial and mental health practitioners to clients. The book can help introduce or guide ongoing discussions about who an individual is in relation to money. In addition, this book offers a variety of real-life examples and exercises for readers, providing an opportunity to gain insight into their financial personalities.
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.
Cooperative Surveillance and Pursuit Using Unmanned Aerial Vehicles and Unattended Ground Sensors
Las Fargeas, Jonathan; Kabamba, Pierre; Girard, Anouck
2015-01-01
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. PMID:25591168
Dr.Arrowsmith's Defiance of Commercialism and His Pursuit of Scientific Truth
Institute of Scientific and Technical Information of China (English)
魏红丽
2005-01-01
Arrowsmith, the most widely reader of Sinclair Lewis's novel, is the dramatic portrayal of a man, Martin Arrowsmith, who passionately devoted to science. Destined to become a physician and a researcher, he discovers that societal forces of commercialism, ignorance, corruption, and greed can be life-threatening obstacles. But he perseveres in his pursuit of scientific truth---even in the face of personal tragedy.Cherishing a spiritual ideal. Through the description o the characteristics of Martin Arrowsmith, Sinclair Lewis greatly attacks the American social reality by singing high praise of the spirits of seeking scientific truth and high medical virtues, while at the same time sharply satiring the commercialism and bureaucratism which dominate most people's minds.
Electrical properties of purinergic transmission in smooth muscle of the guinea-pig prostate.
Lam, Michelle; Mitsui, Retsu; Hashitani, Hikaru
2016-01-01
Prostatic smooth muscle develops spontaneous myogenic tone which is modulated by autonomic neuromuscular transmission. This study aimed to investigate the role of purinergic transmission in regulating electrical activity of prostate smooth muscle and whether its contribution may be altered with age. Intracellular recordings were simultaneously made with isometric tension recordings in smooth muscle preparations of the guinea-pig prostate. Immunostaining for P2X1 receptors on whole mount preparations was also performed. In prostate preparations which generated spontaneous slow waves, electrical field stimulation (EFS)-evoked excitatory junction potentials (EJPs) which were abolished by guanethidine (10 μM), α-β-methylene ATP (10 μM) or pyridoxal phosphate-6-azophenyl-2,4-disulfonic acid (PPADS, 10 μM) but not phentolamine (1 μM). Consistently, immunostaining revealed the expression of P2X1 receptors on prostatic smooth muscle. EJPs themselves did not cause contractions, but EJPs could sum to trigger a slow wave and associated contraction. Yohimbine (1 μM) and 3,7-dimethyl-1-propargylxanthine (DMPX, 10 μM) but not propranolol (1 μM) potentiated EJPs. Although properties of EJPs were not different between young and aging guinea-pig prostates, ectoATPase inhibitor ARL 67156 (100 μM) augmented EJP amplitudes by 64.2 ± 29.6% in aging animals, compared to 22.1 ± 19.9% in young animals. These results suggest that ATP released from sympathetic nerves acts on P2X1 purinoceptors located on prostate smooth muscle to evoke EJPs, while pre-junctional α2-adrenergic and adenosine A2 receptors may play a role in preventing excessive transmitter release. Age-related up-regulation of enzymatic ATP breakdown may be a compensatory mechanism for the enhanced purinergic transmission which would cause hypercontractility arising from increased ATP release in older animals.
Airway smooth muscle NOX4 is upregulated and modulates ROS generation in COPD.
Hollins, Fay; Sutcliffe, Amanda; Gomez, Edith; Berair, Rachid; Russell, Richard; Szyndralewiez, Cédric; Saunders, Ruth; Brightling, Christopher
2016-01-01
The burden of oxidative stress is increased in chronic obstructive pulmonary disease (COPD). However, whether the intra-cellular mechanisms controlling the oxidant/anti-oxidant balance in structural airway cells such as airway smooth muscle in COPD is altered is unclear. We sought to determine whether the expression of the NADPH oxidase (NOX)-4 is increased in airway smooth muscle in COPD both in vivo and primary cells in vitro and its role in hydrogen peroxide-induced reactive oxygen species generation. We found that in vivo NOX4 expression was up-regulated in the airway smooth muscle bundle in COPD (n = 9) and healthy controls with >20 pack year history (n = 4) compared to control subjects without a significant smoking history (n = 6). In vitro NOX4 expression was increased in airway smooth muscle cells from subjects with COPD (n = 5) compared to asthma (n = 7) and upregulated following TNF-α stimulation. Hydrogen peroxide-induced reactive oxygen species generation by airway smooth muscle cells in COPD (n = 5) was comparable to healthy controls (n = 9) but lower than asthma (n = 5); and was markedly attenuated by NOX4 inhibition. Our findings demonstrate that NOX4 expression is increased in vivo and in vitro in COPD and although we did not observe an intrinsic increase in oxidant-induced reactive oxygen species generation in COPD, it was reduced markedly by NOX4 inhibition supporting a potential therapeutic role for NOX4 in COPD. PMID:27435477
International Nuclear Information System (INIS)
The spatial aliasing of seismic data is usually serious because of the sub-sampling rate of the acquisition system. It induces amplitude artifacts or blurs the migration result when the spatial aliasing is not removed before migration. The compressed sensing (CS) method has been proven to be an effective tool to restore a sub-sampled signal which is compressible in another domain. Since the wave-fronts of seismic data are sparse and linear in a local spatiotemporal window, they can be significantly compressed by linear Radon transform or Fourier transform. Therefore, seismic data interpolation can be considered as a CS problem. The approximate solution of a CS problem using L0-norm can be achieved by matching pursuit (MP) algorithm. MP becomes intractable due to the high computing cost induced by the increasing dimension of the problem. In order to tackle this issue, a variant of MP—weighted matching pursuit (WMP)—is presented in this paper. Since there is little spatial aliasing in the data of low frequency and the events are supposed to be linear, the linear Radon spectrogram of the interpolated data of low frequency can be used to predict the energy distribution of data of high frequency in a frequency-wavenumber (FK) domain. The predicted energy distribution is then utilized to form the weighted factor of WMP. With this factor, WMP possesses the ability to distinguish the linear events from the spatial aliasing in the FK domain. WMP is also proven to be an efficient algorithm. Since projection onto convex sets (POCS) is another common sparsity-based method, we use Fourier POCS and WMP to realize high-dimension interpolation in numerical examples. The numerical examples show that the interpolation result of WMP significantly improves the quality of seismic data, and the quality of the migration result is also improved by the interpolation. (paper)
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
International Nuclear Information System (INIS)
The Helmholtz Gemeinschaft groups 15 german research centers to pursuit long dated research objectives in the six following domains: energy, earth, environment, health technology, material structure, transport and aerospace. This document presents the different research programs and their financing. (A.L.B.)
Anderson, James D.
2015-01-01
This article examines the historical relationship between political power and the pursuit of education and social equality from the Reconstruction era to the present. The chief argument is that education equality is historically linked to and even predicated on equal political power, specifically, equal access to the franchise and instruments of…
Cerven, Christine
2013-01-01
Drawing on a case study of 60 low-income single mothers in California, I present a grounded account of the barriers and supports single mothers encounter in their pursuit of postsecondary education (PSE) and detail what the women themselves attributed to their success. I highlight the role both significant others (peers, family, friends) and…
Adaptively Smoothed Seismicity Earthquake Forecasts for Italy
Werner, M J; Jackson, D D; Kagan, Y Y; Wiemer, S
2010-01-01
We present a model for estimating the probabilities of future earthquakes of magnitudes m > 4.95 in Italy. The model, a slightly modified version of the one proposed for California by Helmstetter et al. (2007) and Werner et al. (2010), approximates seismicity by 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 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 historical 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 trustworthy, we used small earthquakes m>2.95 to illuminate active fault structur...
Chemical mixing in smoothed particle hydrodynamics simulations
Greif, Thomas H; Bromm, Volker; Klessen, Ralf S
2008-01-01
We introduce a simple and efficient algorithm for diffusion in smoothed particle hydrodynamics (SPH) simulations and apply it to the problem of chemical mixing. Based on the concept of turbulent diffusion, we link the diffusivity of a pollutant to the local physical conditions and can thus resolve mixing in space and time. We apply our prescription to the evolution of an idealized supernova remnant and find that we can model the distribution of heavy elements without having to explicitly resolve hydrodynamic instabilities in the post-shock gas. Instead, the dispersal of the pollutant is implicitly modeled through its dependence on the local velocity dispersion. Our method can thus be used in any SPH simulation that investigates chemical mixing but lacks the necessary resolution on small scales. Potential applications include the enrichment of the interstellar medium in present-day galaxies, as well as the intergalactic medium at high redshifts.
Chemical mixing in smoothed particle hydrodynamics simulations
Greif, Thomas H.; Glover, Simon C. O.; Bromm, Volker; Klessen, Ralf S.
2009-02-01
We introduce a simple and efficient algorithm for diffusion in smoothed particle hydrodynamics (SPH) simulations and apply it to the problem of chemical mixing. Based on the concept of turbulent diffusion, we link the diffusivity of a pollutant to the local physical conditions and can thus resolve mixing in space and time. We apply our prescription to the evolution of an idealized supernova remnant and find that we can model the distribution of heavy elements without having to explicitly resolve hydrodynamic instabilities in the post-shock gas. Instead, the dispersal of the pollutant is implicitly modelled through its dependence on the local velocity dispersion. Our method can thus be used in any SPH simulation that investigates chemical mixing but lacks the necessary resolution on small scales. Potential applications include the enrichment of the interstellar medium in present-day galaxies, as well as the intergalactic medium at high redshifts.
Contruction of a smoothed DEA frontier
Directory of Open Access Journals (Sweden)
Mello João Carlos Correia Baptista Soares de
2002-01-01
Full Text Available It is known that the DEA multipliers model does not allow a unique solution for the weights. This is due to the absence of unique derivatives in the extreme-efficient points, which is a consequence of the piecewise linear nature of the frontier. In this paper we propose a method to solve this problem, consisting of changing the original DEA frontier for a new one, smooth (with continuous derivatives at every point and closest to the original frontier. We present the theoretical development for the general case, exemplified with the particular case of the BCC model with one input and one output. The 3-dimensional problem is briefly discussed. Some uses of the model are summarised, and one of them, a new Cross-Evaluation model, is presented.
The Smooth-Coated Otter in Nepal
Directory of Open Access Journals (Sweden)
Houghton S.J.
1987-03-01
Full Text Available This study has shown that the Smooth-coated otter is common along the length of the Naryani river and that it relies heavily on fish. It also suggests their feeding habits are sufficiently flexible to adapt to local variations in their food supply. A comparison of river banks suggests human activities decrease the availability of suitable habitat and over-fishing decreases food supply. Extensive deforestation in the hills causes flooding and increases the turbidity of the lowland changing both the aquatic environment and the river's topography. Pollution, resulting from chemical discharge is increasingly an important problem in Nepal. Without an effective management plan controlling these, those animal species dependent on the riverine system may rapidly decrease in number or even disappear permanently.
Resolving mixing in Smoothed Particle Hydrodynamics
Read, J I; Agertz, O
2009-01-01
Standard formulations of smoothed particle hydrodynamics (SPH) are unable to resolve mixing at fluid boundaries. We use an error and stability analysis of the generalised SPH equations of motion to prove that this is due to two distinct problems. The first is a leading order error in the momentum equation. This should decrease with increasing neighbour number, but does not because numerical instabilities cause the kernel to be irregularly sampled. We identify two important instabilities: the clumping instability and the banding instability, and we show that both are cured by a suitable choice of kernel. The second problem is the local mixing instability (LMI). This occurs as particles attempt to mix on the kernel scale, but are unable to due to entropy conservation. The result is a pressure discontinuity at boundaries that pushes fluids of different entropy apart. We cure the LMI by using a temperature weighted density estimate that both reduces errors in the continuity equation and allows individual particle...
PV output smoothing with energy storage.
Energy Technology Data Exchange (ETDEWEB)
Ellis, Abraham; Schoenwald, David Alan
2012-03-01
This report describes an algorithm, implemented in Matlab/Simulink, designed to reduce the variability of photovoltaic (PV) power output by using a battery. The purpose of the battery is to add power to the PV output (or subtract) to smooth out the high frequency components of the PV power that that occur during periods with transient cloud shadows on the PV array. The control system is challenged with the task of reducing short-term PV output variability while avoiding overworking the battery both in terms of capacity and ramp capability. The algorithm proposed by Sandia is purposely very simple to facilitate implementation in a real-time controller. The control structure has two additional inputs to which the battery can respond. For example, the battery could respond to PV variability, load variability or area control error (ACE) or a combination of the three.
Ragot, Hélène; Monfort, Astrid; Baudet, Mathilde; Azibani, Fériel; Fazal, Loubina; Merval, Régine; Polidano, Evelyne; Cohen-Solal, Alain; Delcayre, Claude; Vodovar, Nicolas; Chatziantoniou, Christos; Samuel, Jane-Lise
2016-08-01
Hypertension, which is a risk factor of heart failure, provokes adaptive changes at the vasculature and cardiac levels. Notch3 signaling plays an important role in resistance arteries by controlling the maturation of vascular smooth muscle cells. Notch3 deletion is protective in pulmonary hypertension while deleterious in arterial hypertension. Although this latter phenotype was attributed to renal and cardiac alterations, the underlying mechanisms remained unknown. To investigate the role of Notch3 signaling in the cardiac adaptation to hypertension, we used mice with either constitutive Notch3 or smooth muscle cell-specific conditional RBPJκ knockout. At baseline, both genotypes exhibited a cardiac arteriolar rarefaction associated with oxidative stress. In response to angiotensin II-induced hypertension, the heart of Notch3 knockout and SM-RBPJκ knockout mice did not adapt to pressure overload and developed heart failure, which could lead to an early and fatal acute decompensation of heart failure. This cardiac maladaptation was characterized by an absence of media hypertrophy of the media arteries, the transition of smooth muscle cells toward a synthetic phenotype, and an alteration of angiogenic pathways. A subset of mice exhibited an early fatal acute decompensated heart failure, in which the same alterations were observed, although in a more rapid timeframe. Altogether, these observations indicate that Notch3 plays a major role in coronary adaptation to pressure overload. These data also show that the hypertrophy of coronary arterial media on pressure overload is mandatory to initially maintain a normal cardiac function and is regulated by the Notch3/RBPJκ pathway. PMID:27296994
Adams, Rick A; Bauer, Markus; Pinotsis, Dimitris; Friston, Karl J
2016-05-15
This paper shows that it is possible to estimate the subjective precision (inverse variance) of Bayesian beliefs during oculomotor pursuit. Subjects viewed a sinusoidal target, with or without random fluctuations in its motion. Eye trajectories and magnetoencephalographic (MEG) data were recorded concurrently. The target was periodically occluded, such that its reappearance caused a visual evoked response field (ERF). Dynamic causal modelling (DCM) was used to fit models of eye trajectories and the ERFs. The DCM for pursuit was based on predictive coding and active inference, and predicts subjects' eye movements based on their (subjective) Bayesian beliefs about target (and eye) motion. The precisions of these hierarchical beliefs can be inferred from behavioural (pursuit) data. The DCM for MEG data used an established biophysical model of neuronal activity that includes parameters for the gain of superficial pyramidal cells, which is thought to encode precision at the neuronal level. Previous studies (using DCM of pursuit data) suggest that noisy target motion increases subjective precision at the sensory level: i.e., subjects attend more to the target's sensory attributes. We compared (noisy motion-induced) changes in the synaptic gain based on the modelling of MEG data to changes in subjective precision estimated using the pursuit data. We demonstrate that imprecise target motion increases the gain of superficial pyramidal cells in V1 (across subjects). Furthermore, increases in sensory precision - inferred by our behavioural DCM - correlate with the increase in gain in V1, across subjects. This is a step towards a fully integrated model of brain computations, cortical responses and behaviour that may provide a useful clinical tool in conditions like schizophrenia. PMID:26921713
MATLAB programs for smoothing X-ray spectra
International Nuclear Information System (INIS)
Two MATLAB 4.0 programs for smoothing X-ray spectra: wekskl.m - using polynomial regression splines and wekfft.m - using the fast Fourier transform are presented. The wekskl.m accomplishes smoothing for optimal distances between the knots, whereas the wekff.m uses an optimal spectral window width. The smoothed spectra are available in the form of vectors and are presented in a graphical form as well. (author)
Conjugate Gradient Acceleration of Non-Linear Smoothing Filters
Knyazev, Andrew; Malyshev, Alexander,
2015-01-01
The most efficient signal edge-preserving smoothing filters, e.g., for denoising, are non-linear. Thus, their acceleration is challenging and is often performed in practice by tuning filter parameters, such as by increasing the width of the local smoothing neighborhood, resulting in more aggressive smoothing of a single sweep at the cost of increased edge blurring. We propose an alternative technology, accelerating the original filters without tuning, by running them through a special conjuga...
Retinoic Acid Inhibits Airway Smooth Muscle Cell Migration
Day, Regina M.; Lee, Young H.; Park, Ah-Mee; Suzuki, Yuichiro J.
2006-01-01
Airway remodeling in chronic asthma is characterized by increased smooth muscle mass that is associated with the reduction of the bronchial lumen as well as airway hyperresponsiveness. The development of agents that inhibit smooth muscle growth is therefore of interest for therapy to prevent asthma-associated airway remodeling. All-trans retinoic acid (ATRA) suppresses growth of vascular smooth muscle cells (SMCs) from the systemic and pulmonary circulation. The present study investigated the...
Caveolin-3 promotes a vascular smooth muscle contractile phenotype
Directory of Open Access Journals (Sweden)
Jorge L. Gutierrez-Pajares
2015-06-01
Full Text Available Epidemiological studies have demonstrated the importance of cardiovascular diseases in Western countries. Among the cell types associated with a dysfunctional vasculature, smooth muscle cells are believed to play an essential role in the development of these illnesses. Vascular smooth muscle cells are key regulators of the vascular tone and also have an important function in the development of atherosclerosis and restenosis. While in the normal vasculature contractile smooth muscle cells are predominant, in atherosclerotic vascular lesions, synthetic cells migrate toward the neointima, proliferate, and synthetize extracellular matrix proteins. In the present study, we have examined the role of caveolin-3 in the regulation of smooth muscle cell phenotype. Caveolin-3 is expressed in vivo in normal arterial smooth muscle cells, but its expression appears to be lost in cultured smooth muscle cells. Our data show that caveolin-3 expression in the A7r5 smooth muscle cell line is associated with increased expression of contractility markers such as smooth muscle actin, smooth muscle myosin heavy chain but decreased expression of the synthetic phenotype markers such as p-Elk and Klf4. Moreover, we also show that caveolin-3 expression can reduce proliferation upon treatment with LDL or PDGF. Finally, we show that caveolin-3-expressing smooth muscle cells are less sensitive to apoptosis than control cells upon treatment with oxidized LDL. Taken together, our data suggest that caveolin-3 can regulate the phenotypic switch between contractile and synthetic smooth muscle cells. A better understanding of the factors regulating caveolin-3 expression and function in this cell type will permit the development of a better comprehension of the factors regulating smooth muscle function in atherosclerosis and restenosis.
Smooth muscle myosin: a high force-generating molecular motor.
VanBuren, P; Guilford, W. H.; Kennedy, G.; Wu, J.; Warshaw, D.M.
1995-01-01
Smooth muscle generates as much force per cross sectional area of muscle as skeletal muscle with only one-fifth the myosin content. Although this apparent difference could be explained at the tissue or cellular level, it is possible that at the molecular level smooth muscle cross-bridges generate greater average force than skeletal muscle cross-bridges. To test this hypothesis, we used an in vitro motility assay (VanBuren et al., 1994) in which either chicken thiophosphorylated gizzard smooth...
Six-term exact sequences for smooth generalized crossed products
DEFF Research Database (Denmark)
Gabriel, Olivier; Grensing, Martin
2013-01-01
We define smooth generalized crossed products and prove six-term exact sequences of Pimsner–Voiculescu type. This sequence may, in particular, be applied to smooth subalgebras of the quantum Heisenberg manifolds in order to compute the generators of their cyclic cohomology. Further, our results...... include the known results for smooth crossed products. Our proof is based on a combination of arguments from the setting of (Cuntz–)Pimsner algebras and the Toeplitz proof of Bott periodicity....
Chaotic behaviour from smooth and non-smooth optical solitons under external perturbation
Indian Academy of Sciences (India)
LIUWEI ZHAO; JIULI YIN
2016-08-01
Smooth and non-smooth optical solitons in the nonlinearly dispersive Schrödinger equation are given by phase portraits. The Melnikov technique is used to detect conditions for chaotic motion of this deterministic system and to analyse conditions for the suppression of chaos. Our results show that the system is in a state of Melnikov chaos by external disturbances. After the implementation of the controlled system, the optical solitons can transmit in a stable station for a long time. Numerical simulation also shows that maximum interference frequency of the system enables the dynamic behaviour to be more complex. The effect of controller parameter on phase portraits as well as on the numerical simulations of bifurcation diagram and maximum Lyapunov exponents are also investigated.
Baur, Benedict; Grothaus, Martin
2010-01-01
We prove two assumptions made in an article by Ya.A. Butko, M. Grothaus, O.G. Smolyanov concerning the existence of a strongly continuous operator semigroup solving a Cauchy-Dirichlet problem for an elliptic differential operator in a bounded domain and the existence of a smooth contractive embedding of a core of the generator of the semigroup into the space $C_c^{2,\\alpha}(\\R^n)$. Based on these assumptions a Feynman formula for the solution of the Cauchy-Dirichlet problem is constructed in the article mentioned above. In this article we show that the assumptions are fulfilled for domains with $C^{4,\\alpha}$-smooth boundary and coefficients in $C^{2,\\alpha}$.
Iterated smoothed bootstrap confidence intervals for population quantiles
Lee, SMS; Ho, YHS
2005-01-01
This paper investigates the effects of smoothed bootstrap iterations on coverage probabilities of smoothed bootstrap and bootstrap-t confidence intervals for population quantiles, and establishes the optimal kernel bandwidths at various stages of the smoothing procedures. The conventional smoothed bootstrap and bootstrap-t methods have been known to yield one-sided coverage errors of orders O(n−1/2) and o(n−2/3), respectively, for intervals based on the sample quantile of a random sample of s...
Changes of smooth muscle contractile filaments in small bowel atresia
Institute of Scientific and Technical Information of China (English)
Stefan Gfroerer; Henning Fiegel; Priya Ramachandran; Udo Rolle; Roman Metzger
2012-01-01
AIM:To investigate morphological changes of intestinal smooth muscle contractile fibres in small bowel atresia patients.METHODS:Resected small bowel specimens from small bowel atresia patients (n =12) were divided into three sections (proximal,atretic and distal).Standard histology hematoxylin-eosin staining and enzyme immunohistochemistry was performed to visualize smooth muscle contractile markers α-smooth muscle actin (SMA) and desmin using conventional paraffin sections of the proximal and distal bowel.Small bowel from agematched patients (n =2) undergoing Meckel's diverticulum resection served as controls.RESULTS:The smooth muscle coat in the proximal bowel of small bowel atresia patients was thickened compared with control tissue,but the distal bowel was unchanged.Expression of smooth muscle contractile fibres SMA and desmin within the proximal bowel was slightly reduced compared with the distal bowel and control tissue.There were no major differences in the architecture of the smooth muscle within the proximal bowel and the distal bowel.The proximal and distal bowel in small bowel atresia patients revealed only minimal differences regarding smooth muscle morphology and the presence of smooth muscle contractile filament markers.CONCLUSION:Changes in smooth muscle contractile filaments do not appear to play a major role in postoperative motility disorders in small bowel atresia.
Airway Smooth Muscle Hypercontractility in Asthma
Directory of Open Access Journals (Sweden)
Rachid Berair
2013-01-01
Full Text Available In recent years, asthma has been defined primarily as an inflammatory disorder with emphasis on inflammation being the principle underlying pathophysiological characteristic driving airway obstruction and remodelling. Morphological abnormalities of asthmatic airway smooth muscle (ASM, the primary structure responsible for airway obstruction seen in asthma, have long been described, but surprisingly, until recently, relatively small number of studies investigated whether asthmatic ASM was also fundamentally different in its functional properties. Evidence from recent studies done on single ASM cells and on ASM-impregnated gel cultures have shown that asthmatic ASM is intrinsically hypercontractile. Several elements of the ASM contraction apparatus in asthmatics and in animal models of asthma have been found to be different from nonasthmatics. These differences include some regulatory contractile proteins and also some components of both the calcium-dependent and calcium-independent contraction signalling pathways. Furthermore, oxidative stress was also found to be heightened in asthmatic ASM and contributes to hypercontractility. Understanding the abnormalities and mechanisms driving asthmatic ASM hypercontractility provides a great potential for the development of new targeted drugs, other than the conventional current anti-inflammatory and bronchodilator therapies, to address the desperate unmet need especially in patients with severe and persistent asthma.
A Smoothed Particle Hydrodynamics approach for poroelasticity
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.
Endoscopic management of gastrointestinal smooth muscle tumor
Institute of Scientific and Technical Information of China (English)
Xiao-Dong Zhou; Nong-Hua Lv; Hong-Xia Chen; Chong-Wen Wang; Xuan Zhu; Ping Xu; You-Xiang Chen
2007-01-01
AIM: To systematically evaluate the efficacy and safety of endoscopic resection of gastrointestinal smooth muscle tumors (SMTs, including leiomyoma and leiomyosarcoma) and to review our preliminary experiences on endoscopic diagnosis of gastrointestinal SMTs.METHODS: A total of 69 patients with gastrointestinal SMT underwent routine endoscopy in our department.Endoscopic ultrasonography (EUS) was also performed in 9 cases of gastrointestinal SMT. The sessile submucosal gastrointestinal SMTs with the base smaller than 2 cm in diameter were resected by "pushing" technique or "grasping and pushing" technique while the pedunculated SMTs were resected by polypectomy. For those SMTs originating from muscularis propria or with the base size ≥ 2 cm, ordinary biopsy technique was performed in tumors with ulcers while the "Digging" technique was performed in those without ulcers.RESULTS: 54 cases of leiomyoma and 15 cases of leiomyosarcoma were identified. In them, 19 cases of submucosal leiomyoma were resected by "pushing"technique and 10 cases were removed by "grasping and pushing" technique. Three cases pedunculated submucosal leiomyoma were resected by polypectomy.No severe complications developed during or after the procedure. No recurrence was observed. The diagnostic accuracy of ordinary and the "Digging" biopsy technique was 90.0% and 94.1%, respectively.CONCLUSION: Endoscopic resection is a safe and effective treatment for leiomyomas with the base size ≤2 cm. The "digging" biopsy technique would be a good option for histologic diagnosis of SMTs.
Ambipolar diffusion in smoothed particle magnetohydrodynamics
Wurster, James; Ayliffe, Ben A
2014-01-01
In partially ionised plasmas, the magnetic field can become decoupled from the neutral gas and diffuse through it in a process known as ambipolar diffusion. Although ambipolar diffusion has been implemented in several grid codes, we here provide an implementation in smoothed particle magnetohydrodynamics (SPMHD). We use the strong coupling approximation in which the ion density is negligible, allowing a single fluid approach. The equations are derived to conserve energy, and to provide a positive definite contribution to the entropy. We test the implementation in both a simple 1D SPMHD code and the fully 3D code PHANTOM. The wave damping test yields agreement within 0.03-2 per cent of the analytical result, depending on the value of the collisional coupling constant. The oblique C-shocks test yields results that typically agree within 4 per cent of the semi-analytical result. Our algorithm is therefore suitable for exploring the effect ambipolar diffusion has on physical processes, such as the formation of st...
An implicit Smooth Particle Hydrodynamic code
Energy Technology Data Exchange (ETDEWEB)
Charles E. Knapp
2000-04-01
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.
Smoothing Rotation Curves and Mass Profiles
Berrier, Joel C
2014-01-01
We show that spiral activity can erase pronounced features in disk galaxy rotation curves. We present simulations of growing disks, in which the added material has a physically motivated distribution, as well as other examples of physically less realistic accretion. In all cases, attempts to create unrealistic rotation curves were unsuccessful because spiral activity rapidly smoothed away features in the disk mass profile. The added material was redistributed radially by the spiral activity, which was itself provoked by the density feature. In the case of a ridge-like feature in the surface density profile, we show that two unstable spiral modes develop, and the associated angular momentum changes in horseshoe orbits remove particles from the ridge and spread them both inwards and outwards. This process rapidly erases the density feature from the disk. We also find that the lack of a feature when transitioning from disk to halo dominance in the rotation curves of disk galaxies, the so called "disk-halo conspi...
SMOOTHING ROTATION CURVES AND MASS PROFILES
Energy Technology Data Exchange (ETDEWEB)
Berrier, Joel C.; Sellwood, J. A. [Department of Physics and Astronomy, Rutgers the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States)
2015-02-01
We show that spiral activity can erase pronounced features in disk galaxy rotation curves. We present simulations of growing disks, in which the added material has a physically motivated distribution, as well as other examples of physically less realistic accretion. In all cases, attempts to create unrealistic rotation curves were unsuccessful because spiral activity rapidly smoothed away features in the disk mass profile. The added material was redistributed radially by the spiral activity, which was itself provoked by the density feature. In the case of a ridge-like feature in the surface density profile, we show that two unstable spiral modes develop, and the associated angular momentum changes in horseshoe orbits remove particles from the ridge and spread them both inward and outward. This process rapidly erases the density feature from the disk. We also find that the lack of a feature when transitioning from disk to halo dominance in the rotation curves of disk galaxies, the so called ''disk-halo conspiracy'', could also be accounted for by this mechanism. We do not create perfectly exponential mass profiles in the disk, but suggest that this mechanism contributes to their creation.
Drop splash on a smooth, dry surface
Riboux, Guillaume; Gordillo, Jose Manuel; Korobkin, Alexander
2013-11-01
It is our purpose here to determine the conditions under which a drop of a given liquid with a known radius R impacting against a smooth impermeable surface at a velocity V, will either spread axisymmetrically onto the substrate or will create a splash, giving rise to usually undesired star-shaped patterns. In our experimental setup, drops are generated injecting low viscosity liquids falling under the action of gravity from a stainless steel hypodermic needle. The experimental observations using two high speed cameras operating simultaneously and placed perpendicularly to each other reveal that, initially, the drop deforms axisymmetrically, with A (T) the radius of the wetted area. For high enough values of the drop impact velocity, a thin sheet of liquid starts to be ejected from A (T) at a velocity Vjet > V for instants of time such that T >=Tc . If Vjet is above a certain threshold, which depends on the solid wetting properties as well as on the material properties of both the liquid and the atmospheric gas, the rim of the lamella dewets the solid to finally break into drops. Using Wagner's theory we demonstrate that A (T) =√{ 3 RVT } and our results also reveal that Tc We - 1 / 2 =(ρV2 R / σ) - 1 / 2 and Vjet We 1 / 4 .
Coarctation induces alterations in basement membranes in the cardiovascular system
DEFF Research Database (Denmark)
Lipke, D W; McCarthy, K J; Elton, T S;
1993-01-01
ventricular hypertrophy was maximal within 5 days. In immunohistochemical studies, fibronectin and laminin were increased and the basement membrane chondroitin sulfate proteoglycan decreased in both the subendothelial space and smooth muscle cell basement membranes of the aorta above the clip compared...... membrane components in the heart and vasculature peaked before maximal cardiac hypertrophy (5 days). These studies indicate that alterations in basement membrane component deposition in the hypertrophied vasculature occur at both transcriptional and translational levels and suggest that the cell attachment...
Origin-Destination Flow Data Smoothing and Mapping.
Guo, Diansheng; Zhu, Xi
2014-12-01
This paper presents a new approach to flow mapping that extracts inherent patterns from massive geographic mobility data and constructs effective visual representations of the data for the understanding of complex flow trends. This approach involves a new method for origin-destination flow density estimation and a new method for flow map generalization, which together can remove spurious data variance, normalize flows with control population, and detect high-level patterns that are not discernable with existing approaches. The approach achieves three main objectives in addressing the challenges for analyzing and mapping massive flow data. First, it removes the effect of size differences among spatial units via kernel-based density estimation, which produces a measurement of flow volume between each pair of origin and destination. Second, it extracts major flow patterns in massive flow data through a new flow sampling method, which filters out duplicate information in the smoothed flows. Third, it enables effective flow mapping and allows intuitive perception of flow patterns among origins and destinations without bundling or altering flow paths. The approach can work with both point-based flow data (such as taxi trips with GPS locations) and area-based flow data (such as county-to-county migration). Moreover, the approach can be used to detect and compare flow patterns at different scales or in relatively sparse flow datasets, such as migration for each age group. We evaluate and demonstrate the new approach with case studies of U.S. migration data and experiments with synthetic data. PMID:26356918
Ilagan, Bernadette G; Amsden, Brian G
2009-09-01
Photocrosslinked, biodegradable elastomers based on aliphatic polyesters have many desirable features as scaffolds for smooth muscle tissue engineering. However, they lack cell adhesion motifs. To address this shortcoming, two different modification procedures were studied utilizing a high and a low crosslink density elastomer: base etching and the incorporation of acryloyl-poly(ethylene glycol) (PEG)-Gly-Arg-Gly-Asp-Ser (GRGDS) into the elastomer network during photocrosslinking. Base etching improved surface hydrophilicity without altering surface topography, but did not improve bovine aortic smooth muscle cell adhesion. Incorporation of PEG-GRGDS into the elastomer network significantly improved cell adhesion for both high and low crosslink density elastomers, with a greater effect with the higher crosslink density elastomer. Incorporation of GRGDS into the high crosslink density elastomer also enhanced smooth muscle cell proliferation, while proliferation on the low crosslink density unmodified, base etched, and PEG-GRGDS incorporated elastomers was significantly greater than on the high crosslink density unmodified and base etched elastomer. PMID:19375999
International Nuclear Information System (INIS)
Alteration in the extracellular matrix produced by smooth muscle cells may play a role in the development of atherosclerotic lesions. Consequently the authors have initiated studies on the structural organization of the extracellular matrix produced by cultured smooth muscle cells. Immunohisotological examination of this matrix using well-characterized mono- and polyclonal antibodies showed a partial codistribution of heparan sulfate (HS) proteoglycans with a number of different matrix components including collagen types I, III, IV, V and VI, laminin and fibronectin. Subsequent binding studies between isolated matrix proteins and HS showed that the polysaccharide interacts strongly with type V collagen and to a lesser extent with fibronectin as well as collagen types III and VI. The interaction between type V and HS was readily inhibited by heparin and highly sulfated HS but not be dermatan sulfate, chondroitin sulfate or HS with a low sulfate content. Furthermore, [35S]-HS proteoglycans isolated from cultured smooth muscle cells could be adsorbed on a column of sepharose conjugated with native type V collagen and eluted in a salt gradient. Hence, the interaction between type V and HS may play a major part in stabilizing the extracellular matrix of the vessel wall
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
Smoothing Newton Algorithm for Solving Generalized Complementarity Problem
Institute of Scientific and Technical Information of China (English)
刘晓红; 倪铁
2010-01-01
The generalized complementarity problem includes the well-known nonlinear complementarity problem and linear complementarity problem as special cases.In this paper, based on a class of smoothing functions, a smoothing Newton-type algorithm is proposed for solving the generalized complementarity problem.Under suitable assumptions, the proposed algorithm is well-defined and global convergent.
Smooth surfaces from bilinear patches: Discrete affine minimal surfaces
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.
THE DIFFERENTIAL INTEGRAL EQUATIONS ON SMOOTH CLOSED ORIENTABLE MANIFOLDS
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Using integration by parts and Stokes' formula, the authors give a new definition of Hadamard principal value of higher order singular integrals with Bochner-Martinelli kernel on smooth closed orientable manifolds in Cn. The Plemelj formula and composite formula of higher order singular integral arc obtained. Differential integral equations on smooth closed orientable manifolds are treated by using the composite formula.
Weak Convergence of Smoothed and Nonsmoothed Bootstrap Quantile Estimates
Falk, M; Reiss, R.-D.
1989-01-01
Under fairly general assumptions on the underlying distribution function, the bootstrap process, pertaining to the sample $q$-quantile, converges weakly in $D_\\mathbb{R}$ to the standard Brownian motion. Furthermore, weak convergence of a smoothed bootstrap quantile estimate is proved which entails that in this particular case the smoothed bootstrap estimate outperforms the nonsmoothed one.
Treating asthma means treating airway smooth muscle cells
Zuyderduyn, S; Sukkar, M B; Fust, A; Dhaliwal, S; Burgess, J K
2008-01-01
Asthma is characterised by airway hyperresponsiveness, airway inflammation and airway remodelling. Airway smooth muscle cells are known to be the main effector cells of airway narrowing. In the present paper, studies will be discussed that have led to a novel view of the role of airway smooth muscle
Uterine endometrial stromal sarcoma with rhabdoid and smooth muscle differentiation.
Kim, Y.H.(Center for Underground Physics, Institute for Basic Science (IBS), Daejon, 305-811, Korea); Cho, H; Kyeom-Kim, H.; Kim, I
1996-01-01
Uterine and extrauterine tumors composed of cells featuring endometrial stromal cells often show ovarian sex cord-like structures and smooth muscle differentiation. A few cases of endometrial stromal tumors showing rhabdoid differentiation have been reported. The present case is a 20-year-old woman with endometrial stromal sarcoma that had sex cord-like structures, smooth muscle components and rhabdoid differentiation.
Norm Continuous Unitary Representations of Lie Algebras of Smooth Sections
Neeb, Karl-Hermann; Janssens, Bas
2015-01-01
Let K→X be a smooth Lie algebra bundle over a σ-compact manifold X whose typical fiber is the compact Lie algebra k. We give a complete description of the irreducible bounded (i.e., norm continuous) unitary representations of the Frechet–Lie algebra Γ(K) of all smooth sections of K, and of the LF-Li
Smooth muscle cells largely develop independently of functional hemogenic endothelium
Directory of Open Access Journals (Sweden)
Monika Stefanska
2014-01-01
Full Text Available Vascular smooth muscle cells represent a major component of the cardiovascular system. In vitro studies have shown that FLK1+ cells derived from embryonic stem (ES cells can differentiate into both endothelial and smooth muscle cells. These FLK1+ cells also contain a mesodermal precursor, the hemangioblast, able to produce endothelial, blood and smooth muscle cells. The generation of blood precursors from the hemangioblast was recently shown to occur through a transient cell population of specialised endothelium, a hemogenic endothelium. To date, the lineage relationship between this cell population and smooth muscle cell progenitors has not been investigated. In this study, we generated a reporter ES cell line in which expression of the fluorescent protein H2B-VENUS is driven by the α-smooth muscle actin (α-SMA regulatory sequences. We demonstrated that this reporter cell line efficiently trace smooth muscle development during ES cell differentiation. Although some smooth muscle cells are associated with broad endothelial development, we established that smooth muscle cells are mostly generated independently from a specialised functional hemogenic endothelium. This study provides new and important insights into hematopoietic and vascular development, which may help in driving further progress towards the development of bioengineered vascular grafts for regenerative medicine.
Smooth Quantum Hydrodynamic Model Simulation of the Resonant Tunneling Diode
Carl L. Gardner; Christian Ringhofer
1998-01-01
Smooth quantum hydrodynamic (QHD) model simulations of the resonant tunneling diode are presented which exhibit enhanced negative differential resistance (NDR) when compared to simulations using the original O(ℏ2) QHD model. At both 300 K and 77 K, the smooth QHD simulations predict significant NDR even when the original QHD model simulations predict no NDR.
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 but ...
Smoothing Newton Algorithm for Linear Programming over Symmetric Cones
Institute of Scientific and Technical Information of China (English)
LIU Xiaohong; NI Tie
2009-01-01
By using the theory of Euclidean Jordan algebras,based on a new class of smoothing functions,the QiSun-Zhou's smoothing Newton algorithm is extended to solve linear programming over symmetric cones (SCLP).The algorithm is globally convergent under suitable assumptions.
Data-driven smooth tests when the hypothesis Is composite
Kallenberg, Wilbert 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
Regeneration and Maintenance of Intestinal Smooth Muscle Phenotypes
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
Slope of smooth rational curves in a Fano manifold
Hwang, Jun-Muk; Lee, Yongnam
2010-01-01
Ross and Thomas introduced the concept of slope stability to study K-stability, which has conjectural relation with the existence of constant scalar curvature metric. This paper presents a study of slope stability of Fano manifolds with respect to smooth curves. The question turns out to be easy for curves of genus $\\geq 1$ and the interest lies in the case of smooth rational curves. Our main result says that a Fano manifold $X$ with the anticanonical polarization is slope semistable with respect to any free smooth rational curve, and slope stable with respect to any smooth rational curve $Z$ of anticanonical degree $\\geq 3$, unless $X$ is the projective space and $Z$ is a line. Also we prove that a Fano threefold $X$ with Picard number 1 is slope stable with respect to any smooth rational curve unless $X$ is the projective space.
Reduction of noise in diffusion tensor images using anisotropic smoothing.
Ding, Zhaohua; Gore, John C; Anderson, Adam W
2005-02-01
To improve the accuracy of tissue structural and architectural characterization with diffusion tensor imaging, a novel smoothing technique is developed for reducing noise in diffusion tensor images. The technique extends the traditional anisotropic diffusion filtering method by allowing isotropic smoothing within homogeneous regions and anisotropic smoothing along structure boundaries. This is particularly useful for smoothing diffusion tensor images in which direction information contained in the tensor needs to be restored following noise corruption and preserved around tissue boundaries. The effectiveness of this technique is quantitatively studied with experiments on simulated and human in vivo diffusion tensor data. Illustrative results demonstrate that the anisotropic smoothing technique developed can significantly reduce the impact of noise on the direction as well as anisotropy measures of the diffusion tensor images.
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.
A smoothness constraint on the development of object recognition.
Wood, Justin N
2016-08-01
Understanding how the brain learns to recognize objects is one of the ultimate goals in the cognitive sciences. To date, however, we have not yet characterized the environmental factors that cause object recognition to emerge in the newborn brain. Here, I present the results of a high-throughput controlled-rearing experiment that examined whether the development of object recognition requires experience with temporally smooth visual objects. When newborn chicks (Gallus gallus) were raised with virtual objects that moved smoothly over time, the chicks developed accurate color recognition, shape recognition, and color-shape binding abilities. In contrast, when newborn chicks were raised with virtual objects that moved non-smoothly over time, the chicks' object recognition abilities were severely impaired. These results provide evidence for a "smoothness constraint" on newborn object recognition. Experience with temporally smooth objects facilitates the development of object recognition. PMID:27208825
Filtering of Interferometric SAR Phase Images as a Fuzzy Matching-Pursuit Blind Estimation
Bianchini Massimo; Mori Alessandro; Alparone Luciano; Aiazzi Bruno; Baronti Stefano
2005-01-01
We present an original application of fuzzy logic to restoration of phase images from interferometric synthetic aperture radar (InSAR), which are affected by zero-mean uncorrelated noise, whose variance depends on the underlying coherence, thereby yielding a nonstationary random noise process. Spatial filtering of the phase noise is recommended, either before phase unwrapping is accomplished, or simultaneously with it. In fact, phase unwrapping basically relies on a smoothness constraint of ...
ON THE DERIVATIVE OF SMOOTH MEANINGFUL FUNCTIONS
Directory of Open Access Journals (Sweden)
Sanjo Zlobec
2011-02-01
Full Text Available The derivative of a function f in n variables at a point x* is one of the most important tools in mathematical modelling. If this object exists, it is represented by the row n-tuple f(x* = [∂f/∂xi(x*] called the gradient of f at x*, abbreviated: “the gradient”. The evaluation of f(x* is usually done in two stages, first by calculating the n partials and then their values at x = x*. In this talk we give an alternative approach. We show that one can characterize the gradient without differentiation! The idea is to fix an arbitrary row n-tuple G and answer the following question: What is a necessary and sufficient condition such that G is the gradient of a given f at a given x*? The answer is given after adjusting the quadratic envelope property introduced in [3]. We work with smooth, i.e., continuously differentiable, functions with a Lipschitz derivative on a compact convex set with a non-empty interior. Working with this class of functions is not a serious restriction. In fact, loosely speaking, “almost all” smooth meaningful functions used in modelling of real life situations are expected to have a bounded “acceleration” hence they belong to this class. In particular, the class contains all twice differentiable functions [1]. An important property of the functions from this class is that every f can be represented as the difference of some convex function and a convex quadratic function. This decomposition was used in [3] to characterize the zero derivative points. There we obtained reformulations and augmentations of some well known classic results on optimality such as Fermats extreme value theorem (known from high school and the Lagrange multiplier theorem from calculus [2, 3]. In this talk we extend the results on zero derivative points to characterize the relation G = f(x*, where G is an arbitrary n-tuple. Some special cases: If G = O, we recover the results on zero derivative points. For functions of a single
Neptune's Orbital Migration Was Grainy, Not Smooth
Nesvorný, David; Vokrouhlický, David
2016-07-01
The Kuiper Belt is a population of icy bodies beyond the orbit of Neptune. The complex orbital structure of the Kuiper Belt, including several categories of objects inside and outside of resonances with Neptune, emerged as a result of Neptune’s migration into an outer planetesimal disk. An outstanding problem with the existing migration models is that they invariably predict excessively large resonant populations, while observations show that the non-resonant orbits are in fact common (e.g., the main belt population is ≃2–4 times larger than Plutinos in the 3:2 resonance). Here we show that this problem can be resolved if it is assumed that Neptune’s migration was grainy, as expected from scattering encounters of Neptune with massive planetesimals. The grainy migration acts to destabilize resonant bodies with large libration amplitudes, a fraction of which ends up on stable non-resonant orbits. Thus, the non-resonant-to-resonant ratio obtained with the grainy migration is higher, up to ˜10 times higher for the range of parameters investigated here, than in a model with smooth migration. In addition, the grainy migration leads to a narrower distribution of the libration amplitudes in the 3:2 resonance. The best fit to observations is obtained when it is assumed that the outer planetesimal disk below 30 au contained 1000–4000 Plutos. We estimate that the combined mass of Pluto-class objects in the original disk represented 10%–40% of the estimated disk mass ({M}{{disk}}≃ 20 {M}{{Earth}}). This constraint can be used to better understand the accretion processes in the outer solar system.
Neptune's Orbital Migration Was Grainy, Not Smooth
Nesvorný, David; Vokrouhlický, David
2016-07-01
The Kuiper Belt is a population of icy bodies beyond the orbit of Neptune. The complex orbital structure of the Kuiper Belt, including several categories of objects inside and outside of resonances with Neptune, emerged as a result of Neptune’s migration into an outer planetesimal disk. An outstanding problem with the existing migration models is that they invariably predict excessively large resonant populations, while observations show that the non-resonant orbits are in fact common (e.g., the main belt population is ≃2–4 times larger than Plutinos in the 3:2 resonance). Here we show that this problem can be resolved if it is assumed that Neptune’s migration was grainy, as expected from scattering encounters of Neptune with massive planetesimals. The grainy migration acts to destabilize resonant bodies with large libration amplitudes, a fraction of which ends up on stable non-resonant orbits. Thus, the non-resonant-to-resonant ratio obtained with the grainy migration is higher, up to ∼10 times higher for the range of parameters investigated here, than in a model with smooth migration. In addition, the grainy migration leads to a narrower distribution of the libration amplitudes in the 3:2 resonance. The best fit to observations is obtained when it is assumed that the outer planetesimal disk below 30 au contained 1000–4000 Plutos. We estimate that the combined mass of Pluto-class objects in the original disk represented 10%–40% of the estimated disk mass ({M}{{disk}}≃ 20 {M}{{Earth}}). This constraint can be used to better understand the accretion processes in the outer solar system.
Simulating frictional contact in smoothed particle hydrodynamics
Institute of Scientific and Technical Information of China (English)
WANG; Jian; WU; Hao; GU; ChongShi; HUA; Hui
2013-01-01
Smoothed Particle Hydrodynamics (SPH) is a powerful tool for large deformation computation of soil flow. However, the method to simulate frictional contact in the framework of SPH is still absent and needs to be developed. This paper presents an algorithm to simulate frictional contact between soil and rigid or deformable structure in the framework of SPH. In this algo-rithm, the computational domain is divided into several sub-domains according to the existing contact boundaries, and contact forces are used as bridges of these sub-domains to fulfill problem solving. In the process of the SPH discretization for govern-ing equation of each sub-domain, the inherent problem of boundary deficiency of SPH is handled properly. Therefore, the par-ticles located at contact boundary can have precise acceleration, which is critical for contact detection. Then, based on the as-sumption that the SPH particle of soil can slightly penetrate into the structure, the contact forces along normal and tangential directions of the contact surface are computed by momentum principle, and the frictional force is modified if sliding occurs.Compared with previous methods, in which only particle-to-particle contact is considered or frictional sliding is just ignored,the method proposed in this study is more efficient and accurate, and is suitable for simulating interaction between soft materi-als and rigid or deformable structures, which are very common in geotechnical engineering. A number of numerical tests have been carried out to verify the accuracy and stability of the proposed algorithm, and the results have been compared with ana-lytical solutions or FEM results. The consistency obtained from these comparisons indicates that the algorithm is robust and can enhance the computing capability of SPH.
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.
Baur, Benedict; Conrad, Florian; Grothaus, Martin
2010-01-01
We prove two assumptions made in an article by Ya.A. Butko, M. Grothaus, O.G. Smolyanov concerning the existence of a strongly continuous operator semigroup solving a Cauchy-Dirichlet problem for an elliptic differential operator in a bounded domain and the existence of a smooth contractive embedding of a core of the generator of the semigroup into the space $C_c^{2,\\alpha}(\\R^n)$. Based on these assumptions a Feynman formula for the solution of the Cauchy-Dirichlet problem is constructed in ...
Effects of nitrendipine on growth activity in cultured vascular smooth muscle cells.
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.
Pressure Distribution Over the Fuselage of a PW-9 Pursuit Airplane in Flight
Rhode, Richard V; Lundquist, Eugene E
1932-01-01
This report presents the results obtained from pressure distribution tests on the fuselage of a PW-9 pursuit airplane in a number of conditions of flight. The investigation was made to determine the contribution of the fuselage to the total lift in conditions considered critical for the wing structure, and also to determine whether the fuselage loads acting simultaneously with the maximum tail loads were of such a character as to be of concern with respect to the structural design of other parts of the airplane. The results show that the contribution of the fuselage toward the total lift is small on this airplane. Aerodynamic loads on the fuselage are, in general, unimportant from the structural viewpoint, and in most cases they are of such character that, if neglected, a conservative design results. In spins, aerodynamic forces on the fuselage produce diving moments of appreciable magnitude and yawing moments of small magnitude, but opposing the rotation of the airplane. A table of cowling pressures for various maneuvers is included in the report.
The Pursuit of Quantum Gravity Memoirs of Bryce DeWitt from 1946 to 2004
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...
In pursuit of the ab initio limit for conformational energy prototypes
Császár, Attila G.; Allen, Wesley D.; Schaefer, Henry F.
1998-06-01
The convergence of ab initio predictions to the one- and n-particle limits has been systematically explored for several conformational energy prototypes: the inversion barriers of ammonia, water, and isocyanic acid, the torsional barrier of ethane, the E/Z rotamer separation of formic acid, and the barrier to linearity of silicon dicarbide. Explicit ab initio results were obtained with atomic-orbital basis sets as large as [7s6p5d4f3g2h1i/6s5p4d3f2g1h] and electron correlation treatments as extensive as fifth-order Møller-Plesset perturbation theory (MP5), the full coupled-cluster method through triple excitations (CCSDT), and Brueckner doubles theory including perturbational corrections for both triple and quadruple excitations [BD(TQ)]. Subsequently, basis set and electron correlation extrapolation schemes were invoked to gauge any further variations in arriving at the ab initio limit. Physical effects which are tacitly neglected in most theoretical work have also been quantified by computations of non-Born-Oppenheimer (BODC), relativistic, and core correlation shifts of relative energies. Instructive conclusions are drawn for the pursuit of spectroscopic accuracy in theoretical conformational analyses, and precise predictions for the key energetic quantities of the molecular prototypes are advanced.
Lamb wave based automatic damage detection using matching pursuit and machine learning
International Nuclear Information System (INIS)
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 A0 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)
Exploring the Pursuit of Doctoral Education by Nurses Seeking or Intending to Stay in Faculty Roles.
Dreifuerst, Kristina Thomas; McNelis, Angela M; Weaver, Michael T; Broome, Marion E; Draucker, Claire Burke; Fedko, Andrea S
2016-01-01
The purpose of this study was to describe the factors influencing the pursuit and completion of doctoral education by nurses intending to seek or retain faculty roles. Traditionally, doctoral education evolved to focus on the preparation of nurses to conduct scientific research, primarily through the doctor of philosophy programs. Most recently, the doctor of nursing practice degree emerged and was designed for advanced practice nurses to be clinical leaders who translate research into practice and policy. Nurses who pursue doctoral education in order to assume or maintain faculty roles must choose between these degrees if they desire a doctorate within the discipline; however, factors influencing their decisions and the intended outcomes of their choice are not clear. During this study, 548 nurses (current students or recent graduates of doctoral programs) completed a comprehensive survey to generate critical evidence about the factors influencing the choices made. Principal findings are related to the issues of time, money, and program selection. These findings can be used to develop strategies to increase enrollment and, therefore, the number of doctorally prepared faculty who are specifically prepared to excel as nursing faculty. PMID:27216128
Eddington, Kari M; Majestic, Catherine; Silvia, Paul J
2012-08-01
This study examined the moderating effects of motivational orientation on daily affect and goal pursuit. Based on recent revisions to Reinforcement Sensitivity Theory, measures of BIS (BIS-r and Fight-Flight-Freeze System or FFFS), BAS, and regulatory focus (Promotion and Prevention) were administered to 84 college students who participated in a 14-day diary study. Diary items assessed goal-directed activities and positive and negative affect (PA and NA). Results showed that higher FFFS and Promotion were consistently associated with higher NA and PA, respectively, and FFFS was also associated with avoidance of responsibilities. Higher Promotion predicted greater daily goal progress and tendencies to rate goals as more promotion- and prevention-focused. Relationships between daily goal-directed activities and both sadness and satisfaction were moderated by BIS-r. Inconsistent with our hypothesis, low BAS Reward Responsiveness predicted increased enthusiasm with greater goal progress. A trend in the data showed evidence of regulatory fit in daily activities predicted by both Promotion and Prevention. Implications for the theoretical and practical distinctions between measures of motivational orientation are discussed. PMID:22736878
Patterned fabric defect detection via convolutional matching pursuit dual-dictionary
Jing, Junfeng; Fan, Xiaoting; Li, Pengfei
2016-05-01
Automatic patterned fabric defect detection is a promising technique for textile manufacturing due to its low cost and high efficiency. The applicability of most existing algorithms, however, is limited by their intensive computation. To overcome or alleviate the problem, this paper presents a convolutional matching pursuit (CMP) dual-dictionary algorithm for patterned fabric defect detection. A preprocessing with mean sampling is performed to eliminate the influence of background texture of fabric defects. Subsequently, a set of defect-free image blocks are selected as a sample set by sliding window. Dual-dictionary and sparse coefficiencies of the defect-free sample set are obtained via CMP and the K-singular value decomposition (K-SVD) based on a Gabor filter. Then we employ the defect-free and defective fabric image's projections onto the dual-dictionary as features for defect detection. Finally, the test results are determined by comparing the distance between the features to be measured. Experimental results reveal that the proposed algorithm is effective for patterned fabric defect detection and an acceptable average detection rate reaches by 94.2%.
Pursuit-and-Evasion Reaction-Diffusion Waves in Microreactors with Tailored Geometry.
Zambrano, A; Zadorin, A S; Rondelez, Y; Estévez-Torres, A; Galas, J-C
2015-04-30
Out-of-equilibrium chemical systems may self-organize into structures displaying spatiotemporal order, such as traveling waves and Turing patterns. Because of its predictable chemistry, DNA has recently appeared as an interesting candidate to engineer these spatiotemporal structures. However, in addition to the intrinsic chemical parameters, initial and boundary conditions have a major impact on the final structure. Here we take advantage of microfluidics to design controlled reactors and investigate pursuit-and-evasion chemical waves generated by a DNA-based reaction network with Predator-Prey dynamics. We first propose two complementary microfabrication strategies to either control the initial condition or the two-dimensional geometry of the reactor where the waves develop. We subsequently use them to investigate the effect of curvature in wave propagation. We finally show that DNA-based waves can compute the optimal path within a maze. We thus suggest that coupling configurable microfluidics to programmable DNA-based dissipative reaction networks is a powerful route to investigate spatiotemporal order formation in chemistry. PMID:25839240
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.
Directory of Open Access Journals (Sweden)
Renée Kool
2014-11-01
Full Text Available Since contemporary victims’ policy features the pursuit of procedural justice, the criminal justice authorities have introduced procedural arrangements to serve victims’ voice. Western states use (some form of Victim Impact Statements, providing crime victims with room to inform the courts about the consequences of the crime. Nevertheless, victim voice is contested since it creates an imagery of bias and might cause repeated victimisaton. Indeed, victimologists point at the heterogeneity of victims’ needs, stating that the topical focus on victim voice executed during trial proceedings is one-sighted. Notwithstanding this critique, the Dutch legislator has recently lodged a proposal to introduce a so-called adviesrecht, encompassing the full scheme of the court’s decision-making (guilt and truth finding. Since the Dutch use non-bifurcated trial proceedings, the adviesrecht might have serious repercussions for the standard of a fair trial. A comparative (legal perspective on the (use of the Victim Impact Statement and the Victim Statement of Opinion as used in the United Stated of America appears helpful to expose the potential repercussions of extended victim voice in terms of procedural justice.
Linear Quadratic Differential Game Strategies with Two-pursuit Versus Single-evader
Institute of Scientific and Technical Information of China (English)
LIU Yanfang; QI Naiming; TANG Zhiwei
2012-01-01
In order to intercept the future targets that are characterized by high maneuverability,multiple interceptors may be launched and aimed at single target.The scenario of two missiles P and Q intercepting a single target is modeled as a two-pursuit single-evader non-zero-sum linear quadratic differential game.The intercept space is decomposed into three subspaces which are mutually disjoint and their union covers the entire intercept space.The effect of adding the second interceptor arises in the intercept space of both P and Q (PQ-intercept space).A guidance law is derived from the Nash equilibrium strategy set (NESS) of the game.Simulation studies are focused on the PQ-intercept space.It is indicated that 1) increasing the target's maneuverability will enlarge PQ-intercept space; 2) the handover conditions will be released if the initial zero-effort-miss (ZEM) of both interceptors has opposite sign; 3) overvaluation of the target's maneuverability by choosing a small weight coefficient will generate robust performance with respect to the target maneuvering command switch time and decrease the fuel requirement; and 4) cooperation between interceptors increases the interception probability.
Age, Action Orientation, and Self-Regulation during the Pursuit of a Dieting Goal.
Hennecke, Marie; Freund, Alexandra M
2016-03-01
Two studies tested the hypotheses that (1) action orientation (vs. state orientation) is positively correlated with age across adulthood and (2) action orientation aids the self-regulation of one's feelings, thoughts, and behavior during the pursuit of a dieting goal. Hypotheses were partly confirmed. In Study 1, N = 126 overweight women (age: 19-77 years) intended to lose weight by means of a low-calorie diet. In Study 2, N = 322 adults (age: 18-82 years) reported on their action orientation to replicate the association of age and action orientation found in Study 1. Study 2 corroborated only the expected positive association of age and decision-related action orientation. In Study 1, decision-related action orientation predicted higher affective well-being during the diet as well as less self-reported deviations from the diet; failure-related action orientation predicted lower levels of rumination in response to dieting failures. Action orientation partially mediated the negative effects of age on deviations and rumination (see Hennecke & Freund, ). Weight loss was not predicted by action orientation. We discuss action orientation as one factor of increased motivational competence in older adulthood.
Shen, Dan; Jia, Bin; Chen, Genshe; Blasch, Erik; Pham, Khanh
2015-05-01
This paper develops and evaluates a pursuit-evasion (PE) game approach for elusive orbital maneuver and space object tracking. Unlike the PE games in the literature, where the assumption is that either both players have perfect knowledge of the opponents' positions or use primitive sensing models, the proposed PE approach solves the realistic space situation awareness (SSA) problem with imperfect information, where the evaders will exploit the pursuers' sensing and tracking models to confuse their opponents by maneuvering their orbits to increase the uncertainties, which the pursuers perform orbital maneuvers to minimize. In the game setup, each game player P (pursuer) and E (evader) has its own motion equations with a small continuous low-thrust. The magnitude of the low thrust is fixed and the direction can be controlled by the associated game player. The entropic uncertainty is used to generate the cost functions of game players. The Nash or mixed Nash equilibrium is composed of the directional controls of low-thrusts. Numerical simulations are emulated to demonstrate the performance. Simplified perturbations models (SGP4/SDP4) are exploited to calculate the ground truth of the satellite states (position and speed).
[The Hedonic and Eudaimonic Motives for Activities (HEMA) in Japan: the pursuit of well-being].
Asano, Ryosuke; Igarashi, Tasuku; Tsukamoto, Saori
2014-04-01
Hedonia (seeking pleasure and relaxation) and eudaimonia (seeking to improve oneself in congruence with one's values) uniquely contribute to well-being. The authors developed and tested the construct validity of a Japanese version of the Hedonic and Eudaimonic Motives for Activities (HEMA) scale that had been originally developed in North America. Drawing on the theoretical and empirical evidence from research on emotion, we proposed that people would pursue well-being in three different directions: pleasure, relaxation, and eudaimonia. In Study 1, we used the original HEMA scale to examine the Japanese attainment of well-being. The results supported the hypothesized three-factor model. Study 2 revealed that the Japanese version of the HEMA scale measured pleasure, relaxation, and eudaimonia. Each of these subscales showed statistically sufficient internal consistency. There was no gender difference in any of these measures. Scores on the scale systematically corresponded with external criterion variables, such as life satisfaction, affect, Ryff's psychological well-being, social support, and lifestyle. Implications for psychological research and public policies that cover the topic of the pursuit of well-being are discussed. PMID:24804432
Applying matching pursuit decomposition time-frequency processing to UGS footstep classification
Larsen, Brett W.; Chung, Hugh; Dominguez, Alfonso; Sciacca, Jacob; Kovvali, Narayan; Papandreou-Suppappola, Antonia; Allee, David R.
2013-06-01
The challenge of rapid footstep detection and classification in remote locations has long been an important area of study for defense technology and national security. Also, as the military seeks to create effective and disposable unattended ground sensors (UGS), computational complexity and power consumption have become essential considerations in the development of classification techniques. In response to these issues, a research project at the Flexible Display Center at Arizona State University (ASU) has experimented with footstep classification using the matching pursuit decomposition (MPD) time-frequency analysis method. The MPD provides a parsimonious signal representation by iteratively selecting matched signal components from a pre-determined dictionary. The resulting time-frequency representation of the decomposed signal provides distinctive features for different types of footsteps, including footsteps during walking or running activities. The MPD features were used in a Bayesian classification method to successfully distinguish between the different activities. The computational cost of the iterative MPD algorithm was reduced, without significant loss in performance, using a modified MPD with a dictionary consisting of signals matched to cadence temporal gait patterns obtained from real seismic measurements. The classification results were demonstrated with real data from footsteps under various conditions recorded using a low-cost seismic sensor.
The pursuit of longevity - the bringer of peace to the middle East.
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.
International Nuclear Information System (INIS)
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
Adams, R. A.; Bauer, M.; Pinotsis, D; Friston, K J
2016-01-01
This paper shows that it is possible to estimate the subjective precision (inverse variance) of Bayesian beliefs during oculomotor pursuit. Subjects viewed a sinusoidal target, with or without random fluctuations in its motion. Eye trajectories and magnetoencephalographic (MEG) data were recorded concurrently. The target was periodically occluded, such that its reappearance caused a visual evoked response field (ERF). Dynamic causal modelling (DCM) was used to fit models of eye trajectories a...
Junge, Benjamin; Quiñones, Catherine; Kakietek, Jakub; Teodorescu, Daniel; Marsteller, Pat
2010-01-01
We report on an outcomes assessment of the Summer Undergraduate Research Experience (SURE) Program at Emory University in Atlanta, GA. Using follow-up survey data and academic transcripts, we gauge SURE's impact on levels of interest in, preparedness for, and actual pursuit of graduate study and professional careers in the sciences for the program's first 15 summer cohorts (1990–2004). Our follow-up survey indicated significant increases in all research preparedness skills considered, notably...
Costs and Benefits of Marginal Reallocation of Tax Agency Resources in Pursuit of the Hard-to-Tax
Dimitri Romanov
2003-01-01
As a public sector project carried out by the tax administering agency, pursuit of the hard-to-tax is subject to a cost-benefit analysis. However, considerable intrinsic uncertainty of this project and endogenous dynamic relationship between costs and benefits make the standard model of cost-benefit analysis cumbersome and barely applicable. Two handy techniques may be used instead. One, encompassed by the concept of Marginal Efficiency Cost of Funds, is built around the expected return on th...
Kohls, Gregor; Perino, Michael T.; Taylor, James M.; Madva, Elizabeth N.; Cayless, Sarah J.; Troiani, Vanessa; Price, Elinora; Faja, Susan; Herrington, John D.; Schultz, Robert T.
2013-01-01
Human social motivation is characterized by the pursuit of social reward and the avoidance of social punishment. The ventral striatum/nucleus accumbens (VS/Nacc), in particular, has been implicated in the reward component of social motivation, i.e., the ‘wanting’ of social incentives like approval. However, it is unclear to what extent the VS/Nacc is involved in avoiding social punishment like disapproval, an intrinsically pleasant outcome. Thus, we conducted an event-related functional magne...
Kleiman, Neal; Cokkinos, Dennis; Simoons, Maarten; Harrington, Robert Alex; Califf, Robert; Topol, Eric; Lincoff, Michael; Flaker, G.C.; Pieper, Karen; Wilcox, Robert; Berdan, Lisa; Lorenz, T.J.; Boersma, Eric
2000-01-01
textabstractBACKGROUND: Platelet glycoprotein (GP) IIb/IIIa antagonists prevent the composite end point of death or myocardial infarction (MI) in patients with acute coronary syndromes. There is uncertainty about whether this effect is confined to patients who have percutaneous coronary interventions (PCIs) and whether PCIs further prevent death or MI in patients already treated with GP IIb/IIIa antagonists. METHODS AND RESULTS: PURSUIT patients were treated with the GP IIb/IIIa antagonist ep...
Yarrow, David
2006-01-01
The pursuit of "excellence" is a preoccupation for leaders and change agents who wish their organisations to be the best that they can be. "How do we achieve excellence?", they ask. "Is there a formula, a roadmap?" There is no shortage of offerings: total quality management, business excellence, process redesign, lean thinking... the list seems endless. Advocates of the latest offering trumpet its efficacious properties, sceptics see reinvented wheels, scholars bemoan hype that threatens to d...
Directory of Open Access Journals (Sweden)
Joshua Abrams
2016-05-01
Full Text Available Smooth muscle contraction is controlled by the regulated activity of the myosin heavy chain ATPase (Myh11. Myh11 mutations have diverse effects in the cardiovascular, digestive and genitourinary systems in humans and animal models. We previously reported a recessive missense mutation, meltdown (mlt, which converts a highly conserved tryptophan to arginine (W512R in the rigid relay loop of zebrafish Myh11. The mlt mutation disrupts myosin regulation and non-autonomously induces invasive expansion of the intestinal epithelium. Here, we report two newly identified missense mutations in the switch-1 (S237Y and coil-coiled (L1287M domains of Myh11 that fail to complement mlt. Cell invasion was not detected in either homozygous mutant but could be induced by oxidative stress and activation of oncogenic signaling pathways. The smooth muscle defect imparted by the mlt and S237Y mutations also delayed intestinal transit, and altered vascular function, as measured by blood flow in the dorsal aorta. The cell-invasion phenotype induced by the three myh11 mutants correlated with the degree of myosin deregulation. These findings suggest that the vertebrate intestinal epithelium is tuned to the physical state of the surrounding stroma, which, in turn, governs its response to physiologic and pathologic stimuli. Genetic variants that alter the regulation of smooth muscle myosin might be risk factors for diseases affecting the intestine, vasculature, and other tissues that contain smooth muscle or contractile cells that express smooth muscle proteins, particularly in the setting of redox stress.
KernSmoothIRT: An R Package for Kernel Smoothing in Item Response Theory
Directory of Open Access Journals (Sweden)
Angelo Mazza
2014-06-01
Full Text Available Item response theory (IRT models are a class of statistical models used to describe the response behaviors of individuals to a set of items having a certain number of options. They are adopted by researchers in social science, particularly in the analysis of performance or attitudinal data, in psychology, education, medicine, marketing and other fields where the aim is to measure latent constructs. Most IRT analyses use parametric models that rely on assumptions that often are not satisfied. In such cases, a nonparametric approach might be preferable; nevertheless, there are not many software implementations allowing to use that. To address this gap, this paper presents the R package KernSmoothIRT . It implements kernel smoothing for the estimation of option characteristic curves, and adds several plotting and analytical tools to evaluate the whole test/questionnaire, the items, and the subjects. In order to show the package's capabilities, two real datasets are used, one employing multiple-choice responses, and the other scaled responses.
Efficient computation of smoothing splines via adaptive basis sampling
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(n^{3}). 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.
Separated flow past smooth slender bodies
Williams, Ann Louise
1991-02-01
This dissertation describes an investigation of the separated flow past slender bodies at high angles of attack. Flows of this type occur on aircraft and missile forebodies and can develop large forces which are important when considering stability and control of the vehicle. The objective of this work is to extend the vortex sheet model, which has previously been implemented for slender wings and circular and elliptic cones, to cones of more general cross-section and to non-conical bodies. The cross-sections of the bodies studied here are basically square or triangular, but with rounded corners. The model is inviscid, so the separation positions must be prescribed. Two distinct families of solutions have been identified. For laterally symmetric configurations with symmetric separation positions and no yaw, the first family solutions are symmetric, whereas the second family solutions are asymmetric. For elliptic cones, it is known that cross-section thickness affects the degree of asymmetry of the flow and this represents a mechanism for the control of side forces. Square or triangular cross-sections with rounded corners are of interest to aerodynamicists and have been investigated to assess the effect on asymmetry of making a circular cross-section 'square' or 'triangular'. For 'square' and 'triangular' cones placed either side, or corner on to the flow, results are obtained which enable the effect of cross-section shape on the degree of asymmetry to be assessed. A non-conical vortex sheet model has been developed for the first time for separation from a smooth body. Previously a non-conical line-vortex model was implemented, however lack of representation of vorticity near the separation line limits the applicability of the results. The solution procedure for the non-conical problem consists of a downstream-marching scheme starting from a known solution at the nose. Starting solutions are available if the flow at the nose is assumed conical. With symmetry
AnL1 smoothing spline algorithm with cross validation
Bosworth, Ken W.; Lall, Upmanu
1993-08-01
We propose an algorithm for the computation ofL1 (LAD) smoothing splines in the spacesWM(D), with . We assume one is given data of the formyiD(f(ti) +ɛi, iD1,...,N with {itti}iD1N ⊂D, theɛi are errors withE(ɛi)D0, andf is assumed to be inWM. The LAD smoothing spline, for fixed smoothing parameterλ?;0, is defined as the solution,sλ, of the optimization problem (1/N)∑iD1N yi-g(ti +λJM(g), whereJM(g) is the seminorm consisting of the sum of the squaredL2 norms of theMth partial derivatives ofg. Such an LAD smoothing spline,sλ, would be expected to give robust smoothed estimates off in situations where theɛi are from a distribution with heavy tails. The solution to such a problem is a "thin plate spline" of known form. An algorithm for computingsλ is given which is based on considering a sequence of quadratic programming problems whose structure is guided by the optimality conditions for the above convex minimization problem, and which are solved readily, if a good initial point is available. The "data driven" selection of the smoothing parameter is achieved by minimizing aCV(λ) score of the form .The combined LAD-CV smoothing spline algorithm is a continuation scheme in λ↘0 taken on the above SQPs parametrized inλ, with the optimal smoothing parameter taken to be that value ofλ at which theCV(λ) score first begins to increase. The feasibility of constructing the LAD-CV smoothing spline is illustrated by an application to a problem in environment data interpretation.
Stabilizing S.P.H. with conservative smoothing
Energy Technology Data Exchange (ETDEWEB)
Wen, Y.; Hicks, D.L. [Michigan Tech. Univ., Houghton, MI (United States); Swegle, J.W. [Sandia National Labs., Albuquerque, NM (United States)
1994-08-01
There is an instability in certain S.P.H. (Smoothed Particle Hydrodynamics method) material dynamics computations. Evidence from analyses and experiments suggests that the instabilities in S.P.H. are not removable with artificial viscosities. However, the analysis shows that a type of conservative smoothing does remove the instability. Also, numerical experiments, on certain test problems, show that SPHCS, and S.P.H. code with conservative smoothing, compares well in accuracy with computations based on the von Neumann-Richtmyer method.
Comparison of Two Mesh Smoothing Techniques for Unstructured Grids
International Nuclear Information System (INIS)
In this paper two mesh smoothing techniques are applied to unstructured grids. These are based on the solution of elliptic equations, Laplace and Winslow. In the first case, the equations are solved by a barycentric averaging procedure, and a finite volume scheme is used for the second operator. The comparison of these two techniques are based on two quality measures, shape factor and minimum angle which both are local criteria. Also, a global quality smoothness criterion is introduced and used to assess global smoothing characteristics of these methods
MOTION VELOCITY SMOOTH LINK IN HIGH SPEED MACHINING
Institute of Scientific and Technical Information of China (English)
REN Kun; FU Jianzhong; CHEN Zichen
2007-01-01
To deal with over-shooting and gouging in high speed machining, a novel approach for velocity smooth link is proposed. Considering discrete tool path, cubic spline curve fitting is used to find dangerous points, and according to spatial geometric properties of tool path and the kinematics theory, maximum optimal velocities at dangerous points are obtained. Based on method of velocity control characteristics stored in control system, a fast algorithm for velocity smooth link is analyzed and formulated. On-line implementation results show that the proposed approach makes velocity changing more smoothly compared with traditional velocity control methods and improves productivity greatly.
Smoothed Analysis of Interior-Point Algorithms: Termination
Spielman, Daniel A.; Teng, Shang-Hua
2003-01-01
We perform a smoothed analysis of the termination phase of an interior-point method. By combining this analysis with the smoothed analysis of Renegar's interior-point algorithm by Dunagan, Spielman and Teng, we show that the smoothed complexity of an interior-point algorithm for linear programming is $O (m^{3} \\log (m/\\sigma))$. In contrast, the best known bound on the worst-case complexity of linear programming is $O (m^{3} L)$, where $L$ could be as large as $m$. We include an introduction ...
SMOOTH AFFINE SURFACES WITH NON-UNIQUE C*-ACTIONS
Flenner, Hubert; Kaliman, Shulim; ZAIDENBERG, MIKHAIL
2008-01-01
In this paper we complete the classification of effective C*-actions on smooth affine surfaces up to conjugation in the full automorphism group and up to inversion of C*. If a smooth affine surface V admits more than one C*-action then it is known to be Gizatullin i.e., it can be completed by a linear chain of smooth rational curves. In our previous paper we gave a sufficient condition, in terms of the Dolgachev- Pinkham-Demazure (or DPD) presentation, for the uniqueness of a C*-action on a G...
A Smoothing Inexact Newton Method for Generalized Nonlinear Complementarity Problem
Directory of Open Access Journals (Sweden)
Meixia Li
2012-01-01
Full Text Available Based on the smoothing function of penalized Fischer-Burmeister NCP-function, we propose a new smoothing inexact Newton algorithm with non-monotone line search for solving the generalized nonlinear complementarity problem. We view the smoothing parameter as an independent variable. Under suitable conditions, we show that any accumulation point of the generated sequence is a solution of the generalized nonlinear complementarity problem. We also establish the local superlinear (quadratic convergence of the proposed algorithm under the BD-regular assumption. Preliminary numerical experiments indicate the feasibility and efficiency of the proposed algorithm.
A Brief Analysis Of The Tax Smoothing Hypothesis In Turkey
Directory of Open Access Journals (Sweden)
Mesut KARAKAS
2014-06-01
Full Text Available This study examines the existence of tax smoothing in the case of Turkey using data for the time period between 1923 and 2011. Unit root tests, auto-regression and vector auto-regression (VAR models are applied to tax rates, government expenditures and real output data. Unit root tests and auto-regression results initially point out the existence of tax smoothing in Turkey. However, further in-depth analyses by means of the vector auto-regression model provide strong evidence against the tax smoothing hypothesis for the Turkish case as contemporary tax rates can be predicted with using lagged values of tax rates and government spending rates.
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. PMID:16014803
On rivalry and goal pursuit: Shared competitive history, legacy concerns, and strategy selection.
Converse, Benjamin A; Reinhard, David A
2016-02-01
Seven studies converge to show that prompting people to think about a rival versus a nonrival competitor causes them to view current competitions as more connected to past ones, to be more concerned with long-term legacy, and to pursue personal goals in a more eager, less cautious manner. These results are consistent with a social-cognitive view of rivalry that defines it as a competitive relational schema. A preliminary analysis revealed that people were more likely to appeal to past competitions to explain the importance of current rivalry than nonrivalry contests. Experiment 1 showed that people view rivalry versus nonrivalry competitions as more embedded in an ongoing competitive narrative and that this perception increases legacy concerns. The next 2 experiments used a causal chain approach to examine the possibility of legacy concerns acting as a mediator between rivalry and eagerness. Experiment 2a demonstrated that longer (vs. shorter) competitive histories are associated with increased legacy concerns. Experiment 2b manipulated legacy concerns and found that this shifted regulatory focus toward eagerness. Finally, 3 experiments tested the direct effect of thinking about a rival on eager strategy selection: Thinking about rivals (vs. nonrivals) led people to be more interested in offensive than defensive strategies (Experiment 3), to initiate rather than delay their goal pursuit (Experiment 4), and to rely on spontaneous rather than deliberative reasoning (Experiment 5). We suggest that rivalries affect how people view their goals and the strategies they use for pursuing them, and that these effects are at least partially attributable to the shared history between individuals and their rivals.
On rivalry and goal pursuit: Shared competitive history, legacy concerns, and strategy selection.
Converse, Benjamin A; Reinhard, David A
2016-02-01
Seven studies converge to show that prompting people to think about a rival versus a nonrival competitor causes them to view current competitions as more connected to past ones, to be more concerned with long-term legacy, and to pursue personal goals in a more eager, less cautious manner. These results are consistent with a social-cognitive view of rivalry that defines it as a competitive relational schema. A preliminary analysis revealed that people were more likely to appeal to past competitions to explain the importance of current rivalry than nonrivalry contests. Experiment 1 showed that people view rivalry versus nonrivalry competitions as more embedded in an ongoing competitive narrative and that this perception increases legacy concerns. The next 2 experiments used a causal chain approach to examine the possibility of legacy concerns acting as a mediator between rivalry and eagerness. Experiment 2a demonstrated that longer (vs. shorter) competitive histories are associated with increased legacy concerns. Experiment 2b manipulated legacy concerns and found that this shifted regulatory focus toward eagerness. Finally, 3 experiments tested the direct effect of thinking about a rival on eager strategy selection: Thinking about rivals (vs. nonrivals) led people to be more interested in offensive than defensive strategies (Experiment 3), to initiate rather than delay their goal pursuit (Experiment 4), and to rely on spontaneous rather than deliberative reasoning (Experiment 5). We suggest that rivalries affect how people view their goals and the strategies they use for pursuing them, and that these effects are at least partially attributable to the shared history between individuals and their rivals. PMID:26479360
Bright-field cell image segmentation by principal component pursuit with an Ncut penalization
Chen, Yuehuan; Wan, Justin W. L.
2015-03-01
Segmentation of cells in time-lapse bright-field microscopic images is crucial in understanding cell behaviours for oncological research. However, the complex nature of the cells makes it difficult to segment cells accurately. Furthermore, poor contrast, broken cell boundaries and the halo artifact pose additional challenges to this problem. Standard segmentation techniques such as edged-based methods, watershed, or active contours result in poor segmentation. Other existing methods for bright-field images cannot provide good results without localized segmentation steps. In this paper, we present two robust mathematical models to segment bright-field cells automatically for the entire image. These models treat cell image segmentation as a background subtraction problem, which can be formulated as a Principal Component Pursuit (PCP) problem. Our first segmentation model is formulated as a PCP with nonnegative constraints. We exploit the sparse component of the PCP solution for identifying the cell pixels. However, there is no control on the quality of the sparse component and the nonzero entries can scatter all over the image, resulting in a noisy segmentation. The second model is an improvement of the first model by combining PCP with spectral clustering. Seemingly unrelated approaches, we combine the two techniques by incorporating normalized-cut in the PCP as a measure for the quality of the segmentation. These two models have been applied to a set of C2C12 cells obtained from bright-field microscopy. Experimental results demonstrate that the proposed models are effective in segmenting cells from bright-field images.
At what stage of neural processing does cocaine act to boost pursuit of rewards?
Directory of Open Access Journals (Sweden)
Giovanni Hernandez
Full Text Available Dopamine-containing neurons have been implicated in reward and decision making. One element of the supporting evidence is that cocaine, like other drugs that increase dopaminergic neurotransmission, powerfully potentiates reward seeking. We analyze this phenomenon from a novel perspective, introducing a new conceptual framework and new methodology for determining the stage(s of neural processing at which drugs, lesions and physiological manipulations act to influence reward-seeking behavior. Cocaine strongly boosts the proclivity of rats to work for rewarding electrical brain stimulation. We show that the conventional conceptual framework and methods do not distinguish between three conflicting accounts of how the drug produces this effect: increased sensitivity of brain reward circuitry, increased gain, or decreased subjective reward costs. Sensitivity determines the stimulation strength required to produce a reward of a given intensity (a measure analogous to the KM of an enzyme whereas gain determines the maximum intensity attainable (a measure analogous to the vmax of an enzyme-catalyzed reaction. To distinguish sensitivity changes from the other determinants, we measured and modeled reward seeking as a function of both stimulation strength and opportunity cost. The principal effect of cocaine was a two-fourfold increase in willingness to pay for the electrical reward, an effect consistent with increased gain or decreased subjective cost. This finding challenges the long-standing view that cocaine increases the sensitivity of brain reward circuitry. We discuss the implications of the results and the analytic approach for theories of how dopaminergic neurons and other diffuse modulatory brain systems contribute to reward pursuit, and we explore the implications of the conceptual framework for the study of natural rewards, drug reward, and mood.
Stable smoothed particle magnetohydrodynamics in very steep density gradients
Lewis, Benjamin T; Monaghan, Joseph J; Price, Daniel J
2015-01-01
The equations of smoothed particle magnetohydrodynamics (SPMHD), even with the various corrections to instabilities so far proposed, have been observed to be unstable when a very steep density gradient is necessarily combined with a variable smoothing length formalism. Here we consider in more detail the modifications made to the SPMHD equations in LBP2015 that resolve this instability by replacing the smoothing length in the induction and anisotropic force equations with an average smoothing length term. We then explore the choice of average used and compare the effects on a test `cylinder-in-a-box' problem and the collapse of a magnetised molecular cloud core. We find that, aside from some benign numerical effects at low resolutions for the quadratic mean, the formalism is robust as to the choice of average but that in complicated models it is essential to apply the average to both equations; in particular, all four averages considered exhibit similar conservation properties. This improved formalism allows ...
Hospital to Home: Plan for a Smooth Transition
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 ...
Grey Smoothing Model for Predicting Mine Gas Emission
Institute of Scientific and Technical Information of China (English)
潘结南; 孟召平; 刘亚川
2003-01-01
A grey smoothing model for predicting mine gas emission was presented by combining the grey system theory with the smoothing prediction technique. First of all, according to the variable sequence, GM(1,1) model was set up to predict the general development trend of variable as first fitted values, then the smoothing prediction technique was used to revise the fitted values so as to improve the accuracy of prediction. The results of application in the No.6 Coal Mine in Pingdingshan mining area show that the grey smoothing model has higher accuracy than that of GM(1,1) in predicting the variable sequence with strong fluctuation. The research provides a new scientific method for predicting mine gas emission.
Global smooth solutions of MHD equations with large data
Lin, Yurui; Zhang, Huali; Zhou, Yi
2016-07-01
In this paper, we establish the global existence of smooth solutions of the three-dimensional MHD system for a class of large initial data. Both the initial velocity and magnetic field can be arbitrarily large in the critical norm.
Piecewise-smooth circle homeomorphisms with several break points
International Nuclear Information System (INIS)
We prove that the invariant probability measure of an ergodic piecewise-smooth circle homeomorphism with several break points and the product of the jumps at break points non-trivial is singular with respect to Lebesgue measure.
Origins of increased airway smooth muscle mass in asthma.
Berair, Rachid; Saunders, Ruth; Brightling, Christopher E
2013-01-01
Asthma is characterized by both chronic inflammation and airway remodeling. Remodeling--the structural changes seen in asthmatic airways--is pivotal in the pathogenesis of the disease. Although significant advances have been made recently in understanding the different aspects of airway remodeling, the exact biology governing these changes remains poorly understood. There is broad agreement that, in asthma, increased airway smooth muscle mass, in part due to smooth muscle hyperplasia, is a very significant component of airway remodeling. However, significant debate persists on the origins of these airway smooth muscle cells. In this review article we will explore the natural history of airway remodeling in asthma and we will discuss the possible contribution of progenitors, stem cells and epithelial cells in mesenchymal cell changes, namely airway smooth muscle hyperplasia seen in the asthmatic airways. PMID:23742314
Local Existence of Smooth Solutions to the FENE Dumbbell Model
Institute of Scientific and Technical Information of China (English)
Ge YANG
2012-01-01
The author proves the local existence of smooth solutions to the finite extensible nonlinear elasticity (FENE) dumbbell model of polymeric flows in some weighted spaces if the non-dimensional parameter b ＞ 2.
Smooth sailing through board meetings: practical hints for new chairpersons.
Harney, M K
1983-11-01
The author has some practical and useful suggestions for chairpersons to help keep board meetings running smoothly and efficiently, from the physical arrangement of the room to the formulation of and adherence to agendas.
MATHEMATICAL PROGRAMMING WITH A CLASS OF NON-SMOOTH FUNCTIONS
Institute of Scientific and Technical Information of China (English)
J. DUTTA; V. VETRIVEL
2002-01-01
This is a continuation of a recent work(J. Dutta) on a class of non-smooth functions and their subdifferentials. In this note, necessary optimality conditions are derived for the inequality constrained mathematical programming problems involving such non-smooth functions by employing Gordan's Alternative Theorem. This new approach is simpler than the earlier work of Yang and Craven. Mond-Weir type duality theorems are also obtained.
Conforming restricted Delaunay mesh generation for piecewise smooth complexes
Engwirda, Darren
2016-01-01
A Frontal-Delaunay refinement algorithm for mesh generation in piecewise smooth domains is described. Built using a restricted Delaunay framework, this new algorithm combines a number of novel features, including: (i) a consistent, conforming restricted Delaunay representation for domains specified as a (non-manifold) collection of piecewise smooth surface patches and curve constraints, (ii) a `protection' strategy for domains containing 1-dimensional features that meet at sharply acute angle...
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.
A SMOOTHING CONJUGATE GRADIENT ALGORITHM FOR NONLINEAR COMPLEMENTARITY PROBLEMS
Institute of Scientific and Technical Information of China (English)
Caiying WU; Guoqing CHEN
2008-01-01
A PRP-type smoothing conjugate gradient method for solving large scale nonlinearcomplementarity problems (NCP( F )) is proposed. At each iteration, two Armijo line searches are performed, which guarantees the positive property of the smoothing parameter and minimizes the merit function formed by Fischer-Burmeister function, respectively. Global convergence is studied when F : Rn→Rn is a continuously differentiable P0 + R0 function. Numerical results show that the method is efficient.
MATHEMATICAL PROGRAMMING WITH A CKLASS OF NON－SMOOTH FUNCTIONS
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
This is a continuation of a recent work(J.Dutta)on a class of non-smooth functions and their subdifferentials.In this note,necessary optimality conditions are derived for the inequality constrained mathematical programming problems involving such non-smooth functions by employing Gordan's Alternative Theorem.This new approach is simpler than the earlier work of Yang and Craven.Mond-Weir type duality theorems are also obtained.
Plasma-Spraying Ceramics Onto Smooth Metallic Substrates
Miller, Robert A.; Brindley, William J.; Rouge, Carl J.; Leissler, George
1992-01-01
In fabrication process, plasma-sprayed ceramic coats bonded strongly to smooth metallic surfaces. Principal use of such coats in protecting metal parts in hot-gas paths of advanced gas turbine engines. Process consists of application of initial thin layer of ceramic on smooth surface by low-pressure-plasma spraying followed by application of layer of conventional, low-thermal-conductivity atmospheric-pressure plasma-sprayed ceramic.
Silhouette smoothing for real-time rendering of mesh surfaces
Wang, L.; Tu, C.; W. Wang; Meng, X.; Chan, B; Yan, D.
2008-01-01
Coarse piecewise linear approximation of surfaces causes undesirable polygonal appearance of silhouettes. We present an efficient method for smoothing the silhouettes of coarse triangle meshes using efficient 3D curve reconstruction and simple local re-meshing. It does not assume the availability of a fine mesh and generates only moderate amount of additional data at run time. Furthermore, polygonal feature edges are also smoothed in a unified framework. Our method is based on a novel interpo...
Smoothed universal correlations in the two-dimensional Anderson model
Uski, V.; Mehlig, B.; R.A. Romer; Schreiber, M.
1998-01-01
We report on calculations of smoothed spectral correlations in the two-dimensional Anderson model for weak disorder. As pointed out in (M. Wilkinson, J. Phys. A: Math. Gen. 21, 1173 (1988)), an analysis of the smoothing dependence of the correlation functions provides a sensitive means of establishing consistency with random matrix theory. We use a semiclassical approach to describe these fluctuations and offer a detailed comparison between numerical and analytical calculations for an exhaust...
Managing risks: what Russian households do to smooth consumption?
Notten, Geranda; Neubourg, Chris de
2007-01-01
The increasing availability of rich (panel) data provides many opportunities to test theories on consumption smoothing behaviour. At the same time, the informational requirements in terms of data and modelling are high and very context specific, thus requiring a filtering of essential explanatory ingredients. In this paper we show how conceptual and exploratory empirical analysis can contribute to this filtering process. We develop a conceptual framework to analyze possible smoothing arrangem...
Ureter smooth muscle cell orientation in rat is predominantly longitudinal.
Directory of Open Access Journals (Sweden)
Bart Spronck
Full Text Available In ureter peristalsis, the orientation of the contracting smooth muscle cells is essential, yet current descriptions of orientation and composition of the smooth muscle layer in human as well as in rat ureter are inconsistent. The present study aims to improve quantification of smooth muscle orientation in rat ureters as a basis for mechanistic understanding of peristalsis. A crucial step in our approach is to use two-photon laser scanning microscopy and image analysis providing objective, quantitative data on smooth muscle cell orientation in intact ureters, avoiding the usual sectioning artifacts. In 36 rat ureter segments, originating from a proximal, middle or distal site and from a left or right ureter, we found close to the adventitia a well-defined longitudinal smooth muscle orientation. Towards the lamina propria, the orientation gradually became slightly more disperse, yet the main orientation remained longitudinal. We conclude that smooth muscle cell orientation in rat ureter is predominantly longitudinal, though the orientation gradually becomes more disperse towards the proprial side. These findings do not support identification of separate layers. The observed longitudinal orientation suggests that smooth muscle contraction would rather cause local shortening of the ureter, than cause luminal constriction. However, the net-like connective tissue of the ureter wall may translate local longitudinal shortening into co-local luminal constriction, facilitating peristalsis. Our quantitative, minimally invasive approach is a crucial step towards more mechanistic insight into ureter peristalsis, and may also be used to study smooth muscle cell orientation in other tube-like structures like gut and blood vessels.
Attention Alters Perceived Attractiveness.
Störmer, Viola S; Alvarez, George A
2016-04-01
Can attention alter the impression of a face? Previous studies showed that attention modulates the appearance of lower-level visual features. For instance, attention can make a simple stimulus appear to have higher contrast than it actually does. We tested whether attention can also alter the perception of a higher-order property-namely, facial attractiveness. We asked participants to judge the relative attractiveness of two faces after summoning their attention to one of the faces using a briefly presented visual cue. Across trials, participants judged the attended face to be more attractive than the same face when it was unattended. This effect was not due to decision or response biases, but rather was due to changes in perceptual processing of the faces. These results show that attention alters perceived facial attractiveness, and broadly demonstrate that attention can influence higher-level perception and may affect people's initial impressions of one another. PMID:26966228
Quintic spline smooth semi-supervised support vector classification machine
Institute of Scientific and Technical Information of China (English)
Xiaodan Zhang; Jinggai Ma; Aihua Li; Ang Li
2015-01-01
A semi-supervised vector machine is a relatively new learning method using both labeled and unlabeled data in classifi-cation. Since the objective function of the model for an unstrained semi-supervised vector machine is not smooth, many fast opti-mization algorithms cannot be applied to solve the model. In order to overcome the difficulty of dealing with non-smooth objective functions, new methods that can solve the semi-supervised vector machine with desired classification accuracy are in great demand. A quintic spline function with three-times differentiability at the ori-gin is constructed by a general three-moment method, which can be used to approximate the symmetric hinge loss function. The approximate accuracy of the quintic spline function is estimated. Moreover, a quintic spline smooth semi-support vector machine is obtained and the convergence accuracy of the smooth model to the non-smooth one is analyzed. Three experiments are performed to test the efficiency of the model. The experimental results show that the new model outperforms other smooth models, in terms of classification performance. Furthermore, the new model is not sensitive to the increasing number of the labeled samples, which means that the new model is more efficient.
Delaying natural transition of a boundary layer using smooth steps
Xu, Hui; Sherwin, Spencer J
2015-01-01
The boundary layer flow over a smooth forward-facing stepped plate is studied with particular emphasis on the delay of the transition to turbulence. The interaction between the Tollmien-Schlichting (T-S) waves and the base flow over a single/two forward facing smooth steps is conducted by linear analysis indicating the amplitude of the T-S waves are attenuated in the boundary layer over a single smooth plate. Furthermore, we show that two smooth forward facing steps give rise to a further reduction of the amplitude of the T-S waves. A direct numerical simulation (DNS) is performed for the two smooth forward steps correlating favourably with the linear analysis and showing that for the investigated parameters, the K-type transition is inhibited whereas the turbulence onset of the H-type transition is postponed albeit not suppressed. Transition is indeed delayed and drag reduced for both these transition scenarios suggesting smooth forward facing steps could be leveraged as a passive flow control strategy to de...
The Relationship Between Board Interlocking and Income Smoothing Practices
Directory of Open Access Journals (Sweden)
Flávio Ribeiro
2016-04-01
Full Text Available This study aims to investigate the influence of board interlocking in income smoothing practices in public companies with shares traded on the BM&FBOVESPA. To achieve this objective we adopted a sample comprised of 58 Brazilian companies included in the Bovespa index. The study is classified as empirical and analytical and uses as a proxy for income smoothing a metric called the "smoothing factor" (SF, obtained through the factor analysis technique using the metrics EM1 and EM3 from Leuz, Nanda and Wysocki (2003. As independent variables we employed indicators of social network analysis. From a theoretical point of view, the study is relevant and innovates in making the connection between the resource dependence theory, the agency theory and board interlocking. In practical terms, the study shows the effects of the constitutive elements of corporate social networks, arising from the board interlocking structure, on income smoothing accounting practices. Regression with panel data using fixed effects showed that the constituent elements of corporate social networks tend to influence the practice of smoothing in the sample used. The results of the study show that companies that share board members with other organizations which smooth their results tend to adopt this organizational practice more easily, which can be explained by: (i companies causing variations in performance due to operational decisions or financial reporting choices; and (ii managers making use of discretionary practices in the reporting of profits.
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.
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.
Pires, Carlos A. L.; Ribeiro, Andreia F. S.
2016-04-01
We develop an expansion of space-distributed time series into statistically independent uncorrelated subspaces (statistical sources) of low-dimension and exhibiting enhanced non-Gaussian probability distributions with geometrically simple chosen shapes (projection pursuit rationale). The method relies upon a generalization of the principal component analysis that is optimal for Gaussian mixed signals and of the independent component analysis (ICA), optimized to split non-Gaussian scalar sources. The proposed method, supported by information theory concepts and methods, is the independent subspace analysis (ISA) that looks for multi-dimensional, intrinsically synergetic subspaces such as dyads (2D) and triads (3D), not separable by ICA. Basically, we optimize rotated variables maximizing certain nonlinear correlations (contrast functions) coming from the non-Gaussianity of the joint distribution. As a by-product, it provides nonlinear variable changes `unfolding' the subspaces into nearly Gaussian scalars of easier post-processing. Moreover, the new variables still work as nonlinear data exploratory indices of the non-Gaussian variability of the analysed climatic and geophysical fields. The method (ISA, followed by nonlinear unfolding) is tested into three datasets. The first one comes from the Lorenz'63 three-dimensional chaotic model, showing a clear separation into a non-Gaussian dyad plus an independent scalar. The second one is a mixture of propagating waves of random correlated phases in which the emergence of triadic wave resonances imprints a statistical signature in terms of a non-Gaussian non-separable triad. Finally the method is applied to the monthly variability of a high-dimensional quasi-geostrophic (QG) atmospheric model, applied to the Northern Hemispheric winter. We find that quite enhanced non-Gaussian dyads of parabolic shape, perform much better than the unrotated variables in which concerns the separation of the four model's centroid regimes
Piperine Congeners as Inhibitors of Vascular Smooth Muscle Cell Proliferation.
Mair, Christina E; Liu, Rongxia; Atanasov, Atanas G; Wimmer, Laurin; Nemetz-Fiedler, Daniel; Sider, Nadine; Heiss, Elke H; Mihovilovic, Marko D; Dirsch, Verena M; Rollinger, Judith M
2015-08-01
Successful vascular healing after percutaneous coronary interventions is related to the inhibition of abnormal vascular smooth muscle cell proliferation and efficient re-endothelialization. In the search for vascular smooth muscle cell anti-proliferative agents from natural sources we identified piperine (1), the main pungent constituent of the fruits from Piper nigrum (black pepper). Piperine inhibited vascular smooth muscle cell proliferation with an IC50 of 21.6 µM, as quantified by a resazurin conversion assay. Investigations of ten piperamides isolated from black pepper fruits and 15 synthesized piperine derivatives resulted in the identification of three potent vascular smooth muscle cell proliferation inhibitors: the natural alkaloid pipertipine (4), and the two synthetic derivatives (2E,4E)-N,N-dibutyl-5-(3,5-dimethoxyphenyl)penta-2,4-dienamide (14) and (E)-N,N-dibutyl-3-(naphtho[2,3-d][1,3]dioxol-5-yl)acrylamide (20). They showed IC50 values of 3.38, 6.00, and 7.85 µM, respectively. Furthermore, the synthetic compound (2E,4E)-5-(4-fluorophenyl)-1-(piperidin-1-yl)penta-2,4-dien-1-one (12) was found to be cell type selective, by inhibiting vascular smooth muscle cell proliferation with an IC50 of 11.8 µM without influencing the growth of human endothelial cells. PMID:26132851
Calibrating an updated smoothed particle hydrodynamics scheme within gcd+
Kawata, D.; Okamoto, T.; Gibson, B. K.; Barnes, D. J.; Cen, R.
2013-01-01
We adapt a modern scheme of smoothed particle hydrodynamics (SPH) to our tree N-body/SPH galactic chemodynamics code gcd+. The applied scheme includes implementations of the artificial viscosity switch and artificial thermal conductivity proposed by Morris & Monaghan, Rosswog & Price and Price to model discontinuities and Kelvin-Helmholtz instabilities more accurately. We first present hydrodynamics test simulations and contrast the results to runs undertaken without artificial viscosity switch or thermal conduction. In addition, we also explore the different levels of smoothing by adopting larger or smaller smoothing lengths, i.e. a larger or smaller number of neighbour particles, Nnb. We demonstrate that the new version of gcd+ is capable of modelling Kelvin-Helmholtz instabilities to a similar level as the mesh code, athena. From the Gresho vortex, point-like explosion and self-similar collapse tests, we conclude that setting the smoothing length to keep Nnb as high as ˜58 is preferable to adopting smaller smoothing lengths. We present our optimized parameter sets from the hydrodynamics tests.
Research of beam smoothing technologies using CPP, SSD, and PS
Zhang, Rui; Su, Jingqin; Hu, Dongxia; Li, Ping; Yuan, Haoyu; Zhou, Wei; Yuan, Qiang; Wang, Yuancheng; Tian, Xiaocheng; Xu, Dangpeng; Dong, Jun; Zhu, Qihua
2015-02-01
Precise physical experiments place strict requirements on target illumination uniformity in Inertial Confinement Fusion. To obtain a smoother focal spot and suppress transverse SBS in large aperture optics, Multi-FM smoothing by spectral dispersion (SSD) was studied combined with continuous phase plate (CPP) and polarization smoothing (PS). New ways of PS are being developed to improve the laser irradiation uniformity and solve LPI problems in indirect-drive laser fusion. The near field and far field properties of beams using polarization smoothing were studied and compared, including birefringent wedge and polarization control array. As more parameters can be manipulated in a combined beam smoothing scheme, quad beam smoothing was also studies. Simulation results indicate through adjusting dispersion directions of one-dimensional (1-D) SSD beams in a quad, two-dimensional SSD can be obtained. Experiments have been done on SG-III laser facility using CPP and Multi-FM SSD. The research provides some theoretical and experimental basis for the application of CPP, SSD and PS on high-power laser facilities.
Institute of Scientific and Technical Information of China (English)
陈亚红; 赵鸣武; 刘秀华; 姚婉贞; 杨军; 张肇康; 唐朝枢
2001-01-01
Objective. To investigate the characteristics of urotensin II (U-II) receptor in the rat airway smooth muscleand the effect and signal transduction pathway of U-II on the proliferation of airway smooth muscle cells.Methods. Using 125-UII binding assay to measure the Bmax and Kd of U-II receptor. Using the 3H-TdRincorporation to deter mine the effect of U-II on the proliferation of airway smooth muscle cells and its signal transduc-tion pathway. Using Fura-2/AM to measure the effect of U-II on the cytosolic free calcium concentration.Results. 1. 125I-UⅡ binding increased with the time and reached saturation at 45min. The Bmax was(ll. 36 +0.37)fmol/mg pr and Kd was (4.46 +0.61)nmol/L. 2. U-II increased 3H-TdR incorporation of theairway smooth muscle cells in a dose-dependent manner. 3. H7, PDg8059 and nicardipine, inhibitors of PKC,MAPK, calcium cha.nnel, respectively, significantly inhibited U-II-stimulated 3H-TdR incorporation of airwaysmooth muscle cells. W7, inhibitor of CaM-PK, had no effect. 4. Cyclosporin A, inhibitor of CaN, inhibited3H-TdRincorporation ofthe airway smooth muscle cells induced by U-Ⅱl in a dose-dependent manner. 5. U-Ⅱlpromot-ed cy-tosolic free calcium concentration increase by 18%.Conclusions. 1. There was U-II receptor in the rat airway smooth muscle. 2. The effect of U-II-stimulated-3H-TdR incorporation of airway smooth muscle cells was mediated by such signal transduction pathway as Ca2 +.PKC, MAPK and Ca.N, etc.``
Effects of piperitenone oxide on the intestinal smooth muscle of the guinea pig
Directory of Open Access Journals (Sweden)
P.J.C. Sousa
1997-06-01
Full Text Available We investigated the effects of piperitenone oxide (PO, a major constituent of the essential oil of Mentha x villosa, on the guinea pig ileum. PO (30 to 740 µg/ml relaxed basal tonus without significantly altering the resting membrane potential. In addition, PO relaxed preparations precontracted with either 60 mM K+ or 5 mM tetraethylammonium in a concentration-dependent manner. At concentrations from 0.1 to 10 µg/ml PO potentiated acetylcholine-induced contractions, while higher concentrations (>30 µg/ml blocked this response. These higher PO concentrations also inhibited contractions induced by 60 mM K+. PO also blocked the components of acetylcholine contraction which are not sensitive to nifedipine or to solutions with nominal zero Ca2+ and EGTA. These results show that PO is a relaxant of intestinal smooth muscle and suggest that this activity may be mediated at least in part by an intracellular effect
RSSI-based smooth localization for indoor environment.
Wang, Yujian; Zhao, Bin; Jiang, Zhaohui
2014-01-01
Radio frequency (RF) technique, for its better penetrability over traditional techniques such as infrared or ultrasound, is widely used for indoor localization and tracking. In this paper, three novel measurements, point decision accuracy, path matching error and wrong jumping ratio, are firstly defined to express the localization efficiency. Then, a novel RSSI-based smooth localization (RSL) algorithm is designed, implemented, and evaluated on the WiFi networks. The tree-based mechanism determines the current position and track of the entity by assigning the weights and accumulative weights for all collected RSSI information of reference points so as to make the localization smooth. The evaluation results indicate that the proposed algorithm brings better localization smoothness of reducing 10% path matching error and 30% wrong jumping ratio over the RADAR system. PMID:25143988
Recovering Epipolar Geometry from Images of Smooth Surfaces
Kupervasser, Oleg
2011-01-01
We present four methods for recovering the epipolar geometry from images of smooth surfaces. Existing methods for recovering epipolar geometry use corresponding feature points that cannot be found in such images. The first method is based on finding corresponding characteristic points created by illumination (ICPM - illumination characteristic points method). The second method is based on correspondent tangency points created by tangents from epipoles to outline of smooth bodies (OTPM - outline tangent points method). These two methods are exact and give correct results for real images, because positions of the corresponding illumination characteristic points and corresponding outline are known with small errors. But the second method is limited either to special type of scenes or to restricted camera motion. We also consider two else methods, termed CCPM (curve characteristic points method) and CTPM (curve tangent points method), for search epipolar geometry for images of smooth bodies based on a set of leve...
Tensor classification of structure in smoothed particle hydrodynamics density fields
Forgan, Duncan; Lucas, William; Rice, Ken
2016-01-01
As hydrodynamic simulations increase in scale and resolution, identifying structures with non-trivial geometries or regions of general interest becomes increasingly challenging. There is a growing need for algorithms that identify a variety of different features in a simulation without requiring a "by-eye" search. We present tensor classification as such a technique for smoothed particle hydrodynamics (SPH). These methods have already been used to great effect in N-Body cosmological simulations, which require smoothing defined as an input free parameter. We show that tensor classification successfully identifies a wide range of structures in SPH density fields using its native smoothing, removing a free parameter from the analysis and preventing the need for tesselation of the density field, as required by some classification algorithms. As examples, we show that tensor classification using the tidal tensor and the velocity shear tensor successfully identifies filaments, shells and sheet structures in giant m...
A novel smooth and discontinuous oscillator with strong irrational nonlinearities
Han, YanWei; Cao, QingJie; Chen, YuShu; Wiercigroch, Marian
2012-10-01
In this paper, we propose a novel nonlinear oscillator with strong irrational nonlinearities having smooth and discontinuous characteristics depending on the values of a smoothness parameter. The oscillator is similar to the SD oscillator, originally introduced in Phys Rev E 69(2006). The equilibrium stability and the complex bifurcations of the unperturbed system are investigated. The bifurcation sets of the equilibria in parameter space are constructed to demonstrate transitions in the multiple well dynamics for both smooth and discontinuous regimes. The Melnikov method is employed to obtain the analytical criteria of chaotic thresholds for the singular closed orbits of homoclinic, homo-heteroclinic, cuspidal heteroclinic and tangent homoclinic orbits of the perturbed system.
Adaptive Optical Phase Estimation Using Time-Symmetric Quantum Smoothing
Wheatley, T A; Yonezawa, H; Nakane, D; Arao, H; Pope, D T; Ralph, T C; Wiseman, H M; Furusawa, A; Huntington, E H
2009-01-01
Quantum parameter estimation has many applications, from gravitational wave detection to quantum key distribution. We present the first experimental demonstration of the time-symmetric technique of quantum smoothing. We consider both adaptive and non-adaptive quantum smoothing, and show that both are better than their well-known time-asymmetric counterparts (quantum filtering). For the problem of estimating a stochastically varying phase shift on a coherent beam, our theory predicts that adaptive quantum smoothing (the best scheme) gives an estimate with a mean-square error up to $2\\sqrt{2}$ times smaller than that from non-adaptive quantum filtering (the standard quantum limit). The experimentally measured improvement is $2.24 \\pm 0.14$.
NON-INTERIOR SMOOTHING ALGORITHM FOR FRICTIONAL CONTACT PROBLEMS
Institute of Scientific and Technical Information of China (English)
张洪武; 何素艳; 李兴斯
2004-01-01
A new algorithm for solving the three-dimensional elastic contact problem with friction is presented. The algorithm is a non-interior smoothing algorithm based on an NCPfunction. The parametric variational principle and parametric quadratic programming method were applied to the analysis of three-dimensional frictional contact problem. The solution of the contact problem was finally reduced to a linear complementarity problem, which was reformulated as a system of nonsmooth equations via an NCP-function. A smoothing approximation to the nonsmooth equations was given by the aggregate function. A Newton method was used to solve the resulting smoothing nonlinear equations. The algorithm presented is easy to understand and implement. The reliability and efficiency of this algorithm are demonstrated both by the numerical experiments of LCP in mathematical way and the examples of contact problems in mechanics.
Particle splitting in smoothed particle hydrodynamics based on Voronoi diagram
Chiaki, Gen
2015-01-01
We present a novel method for particle splitting in smoothed particle hydrodynamics simulations. Our method utilizes the Voronoi diagram for a given particle set to determine the position of fine daughter particles. We perform several test simulations to compare our method with a conventional splitting method in which the daughter particles are placed isotropically over the local smoothing length. We show that, with our method, the density deviation after splitting is reduced by a factor of about two compared with the conventional method. Splitting would smooth out the anisotropic density structure if the daughters are distributed isotropically, but our scheme allows the daughter particles to trace the original density distribution with length scales of the mean separation of their parent. We apply the particle splitting to simulations of the primordial gas cloud collapse. The thermal evolution is accurately followed to the hydrogen number density of 10^12 /cc. With the effective mass resolution of ~10^-4 Msu...